Upgrade V8 to 2.4.2

14 files changed, 5368 insertions, 5218 deletions

diff --git a/deps/v8/src/x64/builtins-x64.cc b/deps/v8/src/x64/builtins-x64.cc
index 4f2d2b9616..85ad63719a 100644
--- a/deps/v8/src/x64/builtins-x64.cc
+++ b/deps/v8/src/x64/builtins-x64.cc
@@ -310,8 +310,7 @@ void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
   __ movsxlq(rbx,
              FieldOperand(rdx,
                           SharedFunctionInfo::kFormalParameterCountOffset));
-  __ movq(rdx, FieldOperand(rdi, JSFunction::kCodeOffset));
-  __ lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
+  __ movq(rdx, FieldOperand(rdi, JSFunction::kCodeEntryOffset));
   __ cmpq(rax, rbx);
   __ j(not_equal,
        Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
@@ -876,6 +875,13 @@ void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
 }
 
 
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // TODO(849): implement custom construct stub.
+  // Generate a copy of the generic stub for now.
+  Generate_JSConstructStubGeneric(masm);
+}
+
+
 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax: number of arguments
@@ -898,10 +904,6 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // rdi: called object
   // rax: number of arguments
   __ bind(&non_function_call);
-  // CALL_NON_FUNCTION expects the non-function constructor as receiver
-  // (instead of the original receiver from the call site).  The receiver is
-  // stack element argc+1.
-  __ movq(Operand(rsp, rax, times_pointer_size, kPointerSize), rdi);
   // Set expected number of arguments to zero (not changing rax).
   __ movq(rbx, Immediate(0));
   __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
diff --git a/deps/v8/src/x64/code-stubs-x64.cc b/deps/v8/src/x64/code-stubs-x64.cc
new file mode 100644
index 0000000000..c75b9455b2
--- /dev/null
+++ b/deps/v8/src/x64/code-stubs-x64.cc
@@ -0,0 +1,4015 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#if defined(V8_TARGET_ARCH_X64)
+
+#include "bootstrapper.h"
+#include "code-stubs.h"
+#include "regexp-macro-assembler.h"
+
+namespace v8 {
+namespace internal {
+
+#define __ ACCESS_MASM(masm)
+void FastNewClosureStub::Generate(MacroAssembler* masm) {
+  // Create a new closure from the given function info in new
+  // space. Set the context to the current context in rsi.
+  Label gc;
+  __ AllocateInNewSpace(JSFunction::kSize, rax, rbx, rcx, &gc, TAG_OBJECT);
+
+  // Get the function info from the stack.
+  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
+
+  // Compute the function map in the current global context and set that
+  // as the map of the allocated object.
+  __ movq(rcx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(rcx, FieldOperand(rcx, GlobalObject::kGlobalContextOffset));
+  __ movq(rcx, Operand(rcx, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
+  __ movq(FieldOperand(rax, JSObject::kMapOffset), rcx);
+
+  // Initialize the rest of the function. We don't have to update the
+  // write barrier because the allocated object is in new space.
+  __ LoadRoot(rbx, Heap::kEmptyFixedArrayRootIndex);
+  __ LoadRoot(rcx, Heap::kTheHoleValueRootIndex);
+  __ movq(FieldOperand(rax, JSObject::kPropertiesOffset), rbx);
+  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rbx);
+  __ movq(FieldOperand(rax, JSFunction::kPrototypeOrInitialMapOffset), rcx);
+  __ movq(FieldOperand(rax, JSFunction::kSharedFunctionInfoOffset), rdx);
+  __ movq(FieldOperand(rax, JSFunction::kContextOffset), rsi);
+  __ movq(FieldOperand(rax, JSFunction::kLiteralsOffset), rbx);
+
+  // Initialize the code pointer in the function to be the one
+  // found in the shared function info object.
+  __ movq(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset));
+  __ lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
+  __ movq(FieldOperand(rax, JSFunction::kCodeEntryOffset), rdx);
+
+
+  // Return and remove the on-stack parameter.
+  __ ret(1 * kPointerSize);
+
+  // Create a new closure through the slower runtime call.
+  __ bind(&gc);
+  __ pop(rcx);  // Temporarily remove return address.
+  __ pop(rdx);
+  __ push(rsi);
+  __ push(rdx);
+  __ push(rcx);  // Restore return address.
+  __ TailCallRuntime(Runtime::kNewClosure, 2, 1);
+}
+
+
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+  // Try to allocate the context in new space.
+  Label gc;
+  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+  __ AllocateInNewSpace((length * kPointerSize) + FixedArray::kHeaderSize,
+                        rax, rbx, rcx, &gc, TAG_OBJECT);
+
+  // Get the function from the stack.
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+
+  // Setup the object header.
+  __ LoadRoot(kScratchRegister, Heap::kContextMapRootIndex);
+  __ movq(FieldOperand(rax, HeapObject::kMapOffset), kScratchRegister);
+  __ Move(FieldOperand(rax, FixedArray::kLengthOffset), Smi::FromInt(length));
+
+  // Setup the fixed slots.
+  __ xor_(rbx, rbx);  // Set to NULL.
+  __ movq(Operand(rax, Context::SlotOffset(Context::CLOSURE_INDEX)), rcx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::FCONTEXT_INDEX)), rax);
+  __ movq(Operand(rax, Context::SlotOffset(Context::PREVIOUS_INDEX)), rbx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::EXTENSION_INDEX)), rbx);
+
+  // Copy the global object from the surrounding context.
+  __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(Operand(rax, Context::SlotOffset(Context::GLOBAL_INDEX)), rbx);
+
+  // Initialize the rest of the slots to undefined.
+  __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
+  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+    __ movq(Operand(rax, Context::SlotOffset(i)), rbx);
+  }
+
+  // Return and remove the on-stack parameter.
+  __ movq(rsi, rax);
+  __ ret(1 * kPointerSize);
+
+  // Need to collect. Call into runtime system.
+  __ bind(&gc);
+  __ TailCallRuntime(Runtime::kNewContext, 1, 1);
+}
+
+
+void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
+  // Stack layout on entry:
+  //
+  // [rsp + kPointerSize]: constant elements.
+  // [rsp + (2 * kPointerSize)]: literal index.
+  // [rsp + (3 * kPointerSize)]: literals array.
+
+  // All sizes here are multiples of kPointerSize.
+  int elements_size = (length_ > 0) ? FixedArray::SizeFor(length_) : 0;
+  int size = JSArray::kSize + elements_size;
+
+  // Load boilerplate object into rcx and check if we need to create a
+  // boilerplate.
+  Label slow_case;
+  __ movq(rcx, Operand(rsp, 3 * kPointerSize));
+  __ movq(rax, Operand(rsp, 2 * kPointerSize));
+  SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
+  __ movq(rcx,
+          FieldOperand(rcx, index.reg, index.scale, FixedArray::kHeaderSize));
+  __ CompareRoot(rcx, Heap::kUndefinedValueRootIndex);
+  __ j(equal, &slow_case);
+
+  if (FLAG_debug_code) {
+    const char* message;
+    Heap::RootListIndex expected_map_index;
+    if (mode_ == CLONE_ELEMENTS) {
+      message = "Expected (writable) fixed array";
+      expected_map_index = Heap::kFixedArrayMapRootIndex;
+    } else {
+      ASSERT(mode_ == COPY_ON_WRITE_ELEMENTS);
+      message = "Expected copy-on-write fixed array";
+      expected_map_index = Heap::kFixedCOWArrayMapRootIndex;
+    }
+    __ push(rcx);
+    __ movq(rcx, FieldOperand(rcx, JSArray::kElementsOffset));
+    __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
+                   expected_map_index);
+    __ Assert(equal, message);
+    __ pop(rcx);
+  }
+
+  // Allocate both the JS array and the elements array in one big
+  // allocation. This avoids multiple limit checks.
+  __ AllocateInNewSpace(size, rax, rbx, rdx, &slow_case, TAG_OBJECT);
+
+  // Copy the JS array part.
+  for (int i = 0; i < JSArray::kSize; i += kPointerSize) {
+    if ((i != JSArray::kElementsOffset) || (length_ == 0)) {
+      __ movq(rbx, FieldOperand(rcx, i));
+      __ movq(FieldOperand(rax, i), rbx);
+    }
+  }
+
+  if (length_ > 0) {
+    // Get hold of the elements array of the boilerplate and setup the
+    // elements pointer in the resulting object.
+    __ movq(rcx, FieldOperand(rcx, JSArray::kElementsOffset));
+    __ lea(rdx, Operand(rax, JSArray::kSize));
+    __ movq(FieldOperand(rax, JSArray::kElementsOffset), rdx);
+
+    // Copy the elements array.
+    for (int i = 0; i < elements_size; i += kPointerSize) {
+      __ movq(rbx, FieldOperand(rcx, i));
+      __ movq(FieldOperand(rdx, i), rbx);
+    }
+  }
+
+  // Return and remove the on-stack parameters.
+  __ ret(3 * kPointerSize);
+
+  __ bind(&slow_case);
+  __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 3, 1);
+}
+
+
+void ToBooleanStub::Generate(MacroAssembler* masm) {
+  Label false_result, true_result, not_string;
+  __ movq(rax, Operand(rsp, 1 * kPointerSize));
+
+  // 'null' => false.
+  __ CompareRoot(rax, Heap::kNullValueRootIndex);
+  __ j(equal, &false_result);
+
+  // Get the map and type of the heap object.
+  // We don't use CmpObjectType because we manipulate the type field.
+  __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+  __ movzxbq(rcx, FieldOperand(rdx, Map::kInstanceTypeOffset));
+
+  // Undetectable => false.
+  __ movzxbq(rbx, FieldOperand(rdx, Map::kBitFieldOffset));
+  __ and_(rbx, Immediate(1 << Map::kIsUndetectable));
+  __ j(not_zero, &false_result);
+
+  // JavaScript object => true.
+  __ cmpq(rcx, Immediate(FIRST_JS_OBJECT_TYPE));
+  __ j(above_equal, &true_result);
+
+  // String value => false iff empty.
+  __ cmpq(rcx, Immediate(FIRST_NONSTRING_TYPE));
+  __ j(above_equal, &not_string);
+  __ movq(rdx, FieldOperand(rax, String::kLengthOffset));
+  __ SmiTest(rdx);
+  __ j(zero, &false_result);
+  __ jmp(&true_result);
+
+  __ bind(&not_string);
+  __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
+  __ j(not_equal, &true_result);
+  // HeapNumber => false iff +0, -0, or NaN.
+  // These three cases set the zero flag when compared to zero using ucomisd.
+  __ xorpd(xmm0, xmm0);
+  __ ucomisd(xmm0, FieldOperand(rax, HeapNumber::kValueOffset));
+  __ j(zero, &false_result);
+  // Fall through to |true_result|.
+
+  // Return 1/0 for true/false in rax.
+  __ bind(&true_result);
+  __ movq(rax, Immediate(1));
+  __ ret(1 * kPointerSize);
+  __ bind(&false_result);
+  __ xor_(rax, rax);
+  __ ret(1 * kPointerSize);
+}
+
+
+const char* GenericBinaryOpStub::GetName() {
+  if (name_ != NULL) return name_;
+  const int kMaxNameLength = 100;
+  name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);
+  if (name_ == NULL) return "OOM";
+  const char* op_name = Token::Name(op_);
+  const char* overwrite_name;
+  switch (mode_) {
+    case NO_OVERWRITE: overwrite_name = "Alloc"; break;
+    case OVERWRITE_RIGHT: overwrite_name = "OverwriteRight"; break;
+    case OVERWRITE_LEFT: overwrite_name = "OverwriteLeft"; break;
+    default: overwrite_name = "UnknownOverwrite"; break;
+  }
+
+  OS::SNPrintF(Vector<char>(name_, kMaxNameLength),
+               "GenericBinaryOpStub_%s_%s%s_%s%s_%s_%s",
+               op_name,
+               overwrite_name,
+               (flags_ & NO_SMI_CODE_IN_STUB) ? "_NoSmiInStub" : "",
+               args_in_registers_ ? "RegArgs" : "StackArgs",
+               args_reversed_ ? "_R" : "",
+               static_operands_type_.ToString(),
+               BinaryOpIC::GetName(runtime_operands_type_));
+  return name_;
+}
+
+
+void GenericBinaryOpStub::GenerateCall(
+    MacroAssembler* masm,
+    Register left,
+    Register right) {
+  if (!ArgsInRegistersSupported()) {
+    // Pass arguments on the stack.
+    __ push(left);
+    __ push(right);
+  } else {
+    // The calling convention with registers is left in rdx and right in rax.
+    Register left_arg = rdx;
+    Register right_arg = rax;
+    if (!(left.is(left_arg) && right.is(right_arg))) {
+      if (left.is(right_arg) && right.is(left_arg)) {
+        if (IsOperationCommutative()) {
+          SetArgsReversed();
+        } else {
+          __ xchg(left, right);
+        }
+      } else if (left.is(left_arg)) {
+        __ movq(right_arg, right);
+      } else if (right.is(right_arg)) {
+        __ movq(left_arg, left);
+      } else if (left.is(right_arg)) {
+        if (IsOperationCommutative()) {
+          __ movq(left_arg, right);
+          SetArgsReversed();
+        } else {
+          // Order of moves important to avoid destroying left argument.
+          __ movq(left_arg, left);
+          __ movq(right_arg, right);
+        }
+      } else if (right.is(left_arg)) {
+        if (IsOperationCommutative()) {
+          __ movq(right_arg, left);
+          SetArgsReversed();
+        } else {
+          // Order of moves important to avoid destroying right argument.
+          __ movq(right_arg, right);
+          __ movq(left_arg, left);
+        }
+      } else {
+        // Order of moves is not important.
+        __ movq(left_arg, left);
+        __ movq(right_arg, right);
+      }
+    }
+
+    // Update flags to indicate that arguments are in registers.
+    SetArgsInRegisters();
+    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
+  }
+
+  // Call the stub.
+  __ CallStub(this);
+}
+
+
+void GenericBinaryOpStub::GenerateCall(
+    MacroAssembler* masm,
+    Register left,
+    Smi* right) {
+  if (!ArgsInRegistersSupported()) {
+    // Pass arguments on the stack.
+    __ push(left);
+    __ Push(right);
+  } else {
+    // The calling convention with registers is left in rdx and right in rax.
+    Register left_arg = rdx;
+    Register right_arg = rax;
+    if (left.is(left_arg)) {
+      __ Move(right_arg, right);
+    } else if (left.is(right_arg) && IsOperationCommutative()) {
+      __ Move(left_arg, right);
+      SetArgsReversed();
+    } else {
+      // For non-commutative operations, left and right_arg might be
+      // the same register.  Therefore, the order of the moves is
+      // important here in order to not overwrite left before moving
+      // it to left_arg.
+      __ movq(left_arg, left);
+      __ Move(right_arg, right);
+    }
+
+    // Update flags to indicate that arguments are in registers.
+    SetArgsInRegisters();
+    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
+  }
+
+  // Call the stub.
+  __ CallStub(this);
+}
+
+
+void GenericBinaryOpStub::GenerateCall(
+    MacroAssembler* masm,
+    Smi* left,
+    Register right) {
+  if (!ArgsInRegistersSupported()) {
+    // Pass arguments on the stack.
+    __ Push(left);
+    __ push(right);
+  } else {
+    // The calling convention with registers is left in rdx and right in rax.
+    Register left_arg = rdx;
+    Register right_arg = rax;
+    if (right.is(right_arg)) {
+      __ Move(left_arg, left);
+    } else if (right.is(left_arg) && IsOperationCommutative()) {
+      __ Move(right_arg, left);
+      SetArgsReversed();
+    } else {
+      // For non-commutative operations, right and left_arg might be
+      // the same register.  Therefore, the order of the moves is
+      // important here in order to not overwrite right before moving
+      // it to right_arg.
+      __ movq(right_arg, right);
+      __ Move(left_arg, left);
+    }
+    // Update flags to indicate that arguments are in registers.
+    SetArgsInRegisters();
+    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
+  }
+
+  // Call the stub.
+  __ CallStub(this);
+}
+
+
+class FloatingPointHelper : public AllStatic {
+ public:
+  // Load the operands from rdx and rax into xmm0 and xmm1, as doubles.
+  // If the operands are not both numbers, jump to not_numbers.
+  // Leaves rdx and rax unchanged.  SmiOperands assumes both are smis.
+  // NumberOperands assumes both are smis or heap numbers.
+  static void LoadSSE2SmiOperands(MacroAssembler* masm);
+  static void LoadSSE2NumberOperands(MacroAssembler* masm);
+  static void LoadSSE2UnknownOperands(MacroAssembler* masm,
+                                      Label* not_numbers);
+
+  // Takes the operands in rdx and rax and loads them as integers in rax
+  // and rcx.
+  static void LoadAsIntegers(MacroAssembler* masm,
+                             Label* operand_conversion_failure,
+                             Register heap_number_map);
+  // As above, but we know the operands to be numbers. In that case,
+  // conversion can't fail.
+  static void LoadNumbersAsIntegers(MacroAssembler* masm);
+};
+
+
+void GenericBinaryOpStub::GenerateSmiCode(MacroAssembler* masm, Label* slow) {
+  // 1. Move arguments into rdx, rax except for DIV and MOD, which need the
+  // dividend in rax and rdx free for the division.  Use rax, rbx for those.
+  Comment load_comment(masm, "-- Load arguments");
+  Register left = rdx;
+  Register right = rax;
+  if (op_ == Token::DIV || op_ == Token::MOD) {
+    left = rax;
+    right = rbx;
+    if (HasArgsInRegisters()) {
+      __ movq(rbx, rax);
+      __ movq(rax, rdx);
+    }
+  }
+  if (!HasArgsInRegisters()) {
+    __ movq(right, Operand(rsp, 1 * kPointerSize));
+    __ movq(left, Operand(rsp, 2 * kPointerSize));
+  }
+
+  Label not_smis;
+  // 2. Smi check both operands.
+  if (static_operands_type_.IsSmi()) {
+    // Skip smi check if we know that both arguments are smis.
+    if (FLAG_debug_code) {
+      __ AbortIfNotSmi(left);
+      __ AbortIfNotSmi(right);
+    }
+    if (op_ == Token::BIT_OR) {
+      // Handle OR here, since we do extra smi-checking in the or code below.
+      __ SmiOr(right, right, left);
+      GenerateReturn(masm);
+      return;
+    }
+  } else {
+    if (op_ != Token::BIT_OR) {
+      // Skip the check for OR as it is better combined with the
+      // actual operation.
+      Comment smi_check_comment(masm, "-- Smi check arguments");
+      __ JumpIfNotBothSmi(left, right, &not_smis);
+    }
+  }
+
+  // 3. Operands are both smis (except for OR), perform the operation leaving
+  // the result in rax and check the result if necessary.
+  Comment perform_smi(masm, "-- Perform smi operation");
+  Label use_fp_on_smis;
+  switch (op_) {
+    case Token::ADD: {
+      ASSERT(right.is(rax));
+      __ SmiAdd(right, right, left, &use_fp_on_smis);  // ADD is commutative.
+      break;
+    }
+
+    case Token::SUB: {
+      __ SmiSub(left, left, right, &use_fp_on_smis);
+      __ movq(rax, left);
+      break;
+    }
+
+    case Token::MUL:
+      ASSERT(right.is(rax));
+      __ SmiMul(right, right, left, &use_fp_on_smis);  // MUL is commutative.
+      break;
+
+    case Token::DIV:
+      ASSERT(left.is(rax));
+      __ SmiDiv(left, left, right, &use_fp_on_smis);
+      break;
+
+    case Token::MOD:
+      ASSERT(left.is(rax));
+      __ SmiMod(left, left, right, slow);
+      break;
+
+    case Token::BIT_OR:
+      ASSERT(right.is(rax));
+      __ movq(rcx, right);  // Save the right operand.
+      __ SmiOr(right, right, left);  // BIT_OR is commutative.
+      __ testb(right, Immediate(kSmiTagMask));
+      __ j(not_zero, &not_smis);
+      break;
+
+    case Token::BIT_AND:
+      ASSERT(right.is(rax));
+      __ SmiAnd(right, right, left);  // BIT_AND is commutative.
+      break;
+
+    case Token::BIT_XOR:
+      ASSERT(right.is(rax));
+      __ SmiXor(right, right, left);  // BIT_XOR is commutative.
+      break;
+
+    case Token::SHL:
+    case Token::SHR:
+    case Token::SAR:
+      switch (op_) {
+        case Token::SAR:
+          __ SmiShiftArithmeticRight(left, left, right);
+          break;
+        case Token::SHR:
+          __ SmiShiftLogicalRight(left, left, right, slow);
+          break;
+        case Token::SHL:
+          __ SmiShiftLeft(left, left, right);
+          break;
+        default:
+          UNREACHABLE();
+      }
+      __ movq(rax, left);
+      break;
+
+    default:
+      UNREACHABLE();
+      break;
+  }
+
+  // 4. Emit return of result in rax.
+  GenerateReturn(masm);
+
+  // 5. For some operations emit inline code to perform floating point
+  // operations on known smis (e.g., if the result of the operation
+  // overflowed the smi range).
+  switch (op_) {
+    case Token::ADD:
+    case Token::SUB:
+    case Token::MUL:
+    case Token::DIV: {
+      ASSERT(use_fp_on_smis.is_linked());
+      __ bind(&use_fp_on_smis);
+      if (op_ == Token::DIV) {
+        __ movq(rdx, rax);
+        __ movq(rax, rbx);
+      }
+      // left is rdx, right is rax.
+      __ AllocateHeapNumber(rbx, rcx, slow);
+      FloatingPointHelper::LoadSSE2SmiOperands(masm);
+      switch (op_) {
+        case Token::ADD: __ addsd(xmm0, xmm1); break;
+        case Token::SUB: __ subsd(xmm0, xmm1); break;
+        case Token::MUL: __ mulsd(xmm0, xmm1); break;
+        case Token::DIV: __ divsd(xmm0, xmm1); break;
+        default: UNREACHABLE();
+      }
+      __ movsd(FieldOperand(rbx, HeapNumber::kValueOffset), xmm0);
+      __ movq(rax, rbx);
+      GenerateReturn(masm);
+    }
+    default:
+      break;
+  }
+
+  // 6. Non-smi operands, fall out to the non-smi code with the operands in
+  // rdx and rax.
+  Comment done_comment(masm, "-- Enter non-smi code");
+  __ bind(&not_smis);
+
+  switch (op_) {
+    case Token::DIV:
+    case Token::MOD:
+      // Operands are in rax, rbx at this point.
+      __ movq(rdx, rax);
+      __ movq(rax, rbx);
+      break;
+
+    case Token::BIT_OR:
+      // Right operand is saved in rcx and rax was destroyed by the smi
+      // operation.
+      __ movq(rax, rcx);
+      break;
+
+    default:
+      break;
+  }
+}
+
+
+void GenericBinaryOpStub::Generate(MacroAssembler* masm) {
+  Label call_runtime;
+
+  if (ShouldGenerateSmiCode()) {
+    GenerateSmiCode(masm, &call_runtime);
+  } else if (op_ != Token::MOD) {
+    if (!HasArgsInRegisters()) {
+      GenerateLoadArguments(masm);
+    }
+  }
+  // Floating point case.
+  if (ShouldGenerateFPCode()) {
+    switch (op_) {
+      case Token::ADD:
+      case Token::SUB:
+      case Token::MUL:
+      case Token::DIV: {
+        if (runtime_operands_type_ == BinaryOpIC::DEFAULT &&
+            HasSmiCodeInStub()) {
+          // Execution reaches this point when the first non-smi argument occurs
+          // (and only if smi code is generated). This is the right moment to
+          // patch to HEAP_NUMBERS state. The transition is attempted only for
+          // the four basic operations. The stub stays in the DEFAULT state
+          // forever for all other operations (also if smi code is skipped).
+          GenerateTypeTransition(masm);
+          break;
+        }
+
+        Label not_floats;
+        // rax: y
+        // rdx: x
+        if (static_operands_type_.IsNumber()) {
+          if (FLAG_debug_code) {
+            // Assert at runtime that inputs are only numbers.
+            __ AbortIfNotNumber(rdx);
+            __ AbortIfNotNumber(rax);
+          }
+          FloatingPointHelper::LoadSSE2NumberOperands(masm);
+        } else {
+          FloatingPointHelper::LoadSSE2UnknownOperands(masm, &call_runtime);
+        }
+
+        switch (op_) {
+          case Token::ADD: __ addsd(xmm0, xmm1); break;
+          case Token::SUB: __ subsd(xmm0, xmm1); break;
+          case Token::MUL: __ mulsd(xmm0, xmm1); break;
+          case Token::DIV: __ divsd(xmm0, xmm1); break;
+          default: UNREACHABLE();
+        }
+        // Allocate a heap number, if needed.
+        Label skip_allocation;
+        OverwriteMode mode = mode_;
+        if (HasArgsReversed()) {
+          if (mode == OVERWRITE_RIGHT) {
+            mode = OVERWRITE_LEFT;
+          } else if (mode == OVERWRITE_LEFT) {
+            mode = OVERWRITE_RIGHT;
+          }
+        }
+        switch (mode) {
+          case OVERWRITE_LEFT:
+            __ JumpIfNotSmi(rdx, &skip_allocation);
+            __ AllocateHeapNumber(rbx, rcx, &call_runtime);
+            __ movq(rdx, rbx);
+            __ bind(&skip_allocation);
+            __ movq(rax, rdx);
+            break;
+          case OVERWRITE_RIGHT:
+            // If the argument in rax is already an object, we skip the
+            // allocation of a heap number.
+            __ JumpIfNotSmi(rax, &skip_allocation);
+            // Fall through!
+          case NO_OVERWRITE:
+            // Allocate a heap number for the result. Keep rax and rdx intact
+            // for the possible runtime call.
+            __ AllocateHeapNumber(rbx, rcx, &call_runtime);
+            __ movq(rax, rbx);
+            __ bind(&skip_allocation);
+            break;
+          default: UNREACHABLE();
+        }
+        __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), xmm0);
+        GenerateReturn(masm);
+        __ bind(&not_floats);
+        if (runtime_operands_type_ == BinaryOpIC::DEFAULT &&
+            !HasSmiCodeInStub()) {
+            // Execution reaches this point when the first non-number argument
+            // occurs (and only if smi code is skipped from the stub, otherwise
+            // the patching has already been done earlier in this case branch).
+            // A perfect moment to try patching to STRINGS for ADD operation.
+            if (op_ == Token::ADD) {
+              GenerateTypeTransition(masm);
+            }
+        }
+        break;
+      }
+      case Token::MOD: {
+        // For MOD we go directly to runtime in the non-smi case.
+        break;
+      }
+      case Token::BIT_OR:
+      case Token::BIT_AND:
+      case Token::BIT_XOR:
+      case Token::SAR:
+      case Token::SHL:
+      case Token::SHR: {
+        Label skip_allocation, non_smi_shr_result;
+        Register heap_number_map = r9;
+        __ LoadRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
+        if (static_operands_type_.IsNumber()) {
+          if (FLAG_debug_code) {
+            // Assert at runtime that inputs are only numbers.
+            __ AbortIfNotNumber(rdx);
+            __ AbortIfNotNumber(rax);
+          }
+          FloatingPointHelper::LoadNumbersAsIntegers(masm);
+        } else {
+          FloatingPointHelper::LoadAsIntegers(masm,
+                                              &call_runtime,
+                                              heap_number_map);
+        }
+        switch (op_) {
+          case Token::BIT_OR:  __ orl(rax, rcx); break;
+          case Token::BIT_AND: __ andl(rax, rcx); break;
+          case Token::BIT_XOR: __ xorl(rax, rcx); break;
+          case Token::SAR: __ sarl_cl(rax); break;
+          case Token::SHL: __ shll_cl(rax); break;
+          case Token::SHR: {
+            __ shrl_cl(rax);
+            // Check if result is negative. This can only happen for a shift
+            // by zero.
+            __ testl(rax, rax);
+            __ j(negative, &non_smi_shr_result);
+            break;
+          }
+          default: UNREACHABLE();
+        }
+
+        STATIC_ASSERT(kSmiValueSize == 32);
+        // Tag smi result and return.
+        __ Integer32ToSmi(rax, rax);
+        GenerateReturn(masm);
+
+        // All bit-ops except SHR return a signed int32 that can be
+        // returned immediately as a smi.
+        // We might need to allocate a HeapNumber if we shift a negative
+        // number right by zero (i.e., convert to UInt32).
+        if (op_ == Token::SHR) {
+          ASSERT(non_smi_shr_result.is_linked());
+          __ bind(&non_smi_shr_result);
+          // Allocate a heap number if needed.
+          __ movl(rbx, rax);  // rbx holds result value (uint32 value as int64).
+          switch (mode_) {
+            case OVERWRITE_LEFT:
+            case OVERWRITE_RIGHT:
+              // If the operand was an object, we skip the
+              // allocation of a heap number.
+              __ movq(rax, Operand(rsp, mode_ == OVERWRITE_RIGHT ?
+                                   1 * kPointerSize : 2 * kPointerSize));
+              __ JumpIfNotSmi(rax, &skip_allocation);
+              // Fall through!
+            case NO_OVERWRITE:
+              // Allocate heap number in new space.
+              // Not using AllocateHeapNumber macro in order to reuse
+              // already loaded heap_number_map.
+              __ AllocateInNewSpace(HeapNumber::kSize,
+                                    rax,
+                                    rcx,
+                                    no_reg,
+                                    &call_runtime,
+                                    TAG_OBJECT);
+              // Set the map.
+              if (FLAG_debug_code) {
+                __ AbortIfNotRootValue(heap_number_map,
+                                       Heap::kHeapNumberMapRootIndex,
+                                       "HeapNumberMap register clobbered.");
+              }
+              __ movq(FieldOperand(rax, HeapObject::kMapOffset),
+                      heap_number_map);
+              __ bind(&skip_allocation);
+              break;
+            default: UNREACHABLE();
+          }
+          // Store the result in the HeapNumber and return.
+          __ cvtqsi2sd(xmm0, rbx);
+          __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), xmm0);
+          GenerateReturn(masm);
+        }
+
+        break;
+      }
+      default: UNREACHABLE(); break;
+    }
+  }
+
+  // If all else fails, use the runtime system to get the correct
+  // result. If arguments was passed in registers now place them on the
+  // stack in the correct order below the return address.
+  __ bind(&call_runtime);
+
+  if (HasArgsInRegisters()) {
+    GenerateRegisterArgsPush(masm);
+  }
+
+  switch (op_) {
+    case Token::ADD: {
+      // Registers containing left and right operands respectively.
+      Register lhs, rhs;
+
+      if (HasArgsReversed()) {
+        lhs = rax;
+        rhs = rdx;
+      } else {
+        lhs = rdx;
+        rhs = rax;
+      }
+
+      // Test for string arguments before calling runtime.
+      Label not_strings, both_strings, not_string1, string1, string1_smi2;
+
+      // If this stub has already generated FP-specific code then the arguments
+      // are already in rdx and rax.
+      if (!ShouldGenerateFPCode() && !HasArgsInRegisters()) {
+        GenerateLoadArguments(masm);
+      }
+
+      Condition is_smi;
+      is_smi = masm->CheckSmi(lhs);
+      __ j(is_smi, &not_string1);
+      __ CmpObjectType(lhs, FIRST_NONSTRING_TYPE, r8);
+      __ j(above_equal, &not_string1);
+
+      // First argument is a a string, test second.
+      is_smi = masm->CheckSmi(rhs);
+      __ j(is_smi, &string1_smi2);
+      __ CmpObjectType(rhs, FIRST_NONSTRING_TYPE, r9);
+      __ j(above_equal, &string1);
+
+      // First and second argument are strings.
+      StringAddStub string_add_stub(NO_STRING_CHECK_IN_STUB);
+      __ TailCallStub(&string_add_stub);
+
+      __ bind(&string1_smi2);
+      // First argument is a string, second is a smi. Try to lookup the number
+      // string for the smi in the number string cache.
+      NumberToStringStub::GenerateLookupNumberStringCache(
+          masm, rhs, rbx, rcx, r8, true, &string1);
+
+      // Replace second argument on stack and tailcall string add stub to make
+      // the result.
+      __ movq(Operand(rsp, 1 * kPointerSize), rbx);
+      __ TailCallStub(&string_add_stub);
+
+      // Only first argument is a string.
+      __ bind(&string1);
+      __ InvokeBuiltin(Builtins::STRING_ADD_LEFT, JUMP_FUNCTION);
+
+      // First argument was not a string, test second.
+      __ bind(&not_string1);
+      is_smi = masm->CheckSmi(rhs);
+      __ j(is_smi, &not_strings);
+      __ CmpObjectType(rhs, FIRST_NONSTRING_TYPE, rhs);
+      __ j(above_equal, &not_strings);
+
+      // Only second argument is a string.
+      __ InvokeBuiltin(Builtins::STRING_ADD_RIGHT, JUMP_FUNCTION);
+
+      __ bind(&not_strings);
+      // Neither argument is a string.
+      __ InvokeBuiltin(Builtins::ADD, JUMP_FUNCTION);
+      break;
+    }
+    case Token::SUB:
+      __ InvokeBuiltin(Builtins::SUB, JUMP_FUNCTION);
+      break;
+    case Token::MUL:
+      __ InvokeBuiltin(Builtins::MUL, JUMP_FUNCTION);
+      break;
+    case Token::DIV:
+      __ InvokeBuiltin(Builtins::DIV, JUMP_FUNCTION);
+      break;
+    case Token::MOD:
+      __ InvokeBuiltin(Builtins::MOD, JUMP_FUNCTION);
+      break;
+    case Token::BIT_OR:
+      __ InvokeBuiltin(Builtins::BIT_OR, JUMP_FUNCTION);
+      break;
+    case Token::BIT_AND:
+      __ InvokeBuiltin(Builtins::BIT_AND, JUMP_FUNCTION);
+      break;
+    case Token::BIT_XOR:
+      __ InvokeBuiltin(Builtins::BIT_XOR, JUMP_FUNCTION);
+      break;
+    case Token::SAR:
+      __ InvokeBuiltin(Builtins::SAR, JUMP_FUNCTION);
+      break;
+    case Token::SHL:
+      __ InvokeBuiltin(Builtins::SHL, JUMP_FUNCTION);
+      break;
+    case Token::SHR:
+      __ InvokeBuiltin(Builtins::SHR, JUMP_FUNCTION);
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void GenericBinaryOpStub::GenerateLoadArguments(MacroAssembler* masm) {
+  ASSERT(!HasArgsInRegisters());
+  __ movq(rax, Operand(rsp, 1 * kPointerSize));
+  __ movq(rdx, Operand(rsp, 2 * kPointerSize));
+}
+
+
+void GenericBinaryOpStub::GenerateReturn(MacroAssembler* masm) {
+  // If arguments are not passed in registers remove them from the stack before
+  // returning.
+  if (!HasArgsInRegisters()) {
+    __ ret(2 * kPointerSize);  // Remove both operands
+  } else {
+    __ ret(0);
+  }
+}
+
+
+void GenericBinaryOpStub::GenerateRegisterArgsPush(MacroAssembler* masm) {
+  ASSERT(HasArgsInRegisters());
+  __ pop(rcx);
+  if (HasArgsReversed()) {
+    __ push(rax);
+    __ push(rdx);
+  } else {
+    __ push(rdx);
+    __ push(rax);
+  }
+  __ push(rcx);
+}
+
+
+void GenericBinaryOpStub::GenerateTypeTransition(MacroAssembler* masm) {
+  Label get_result;
+
+  // Ensure the operands are on the stack.
+  if (HasArgsInRegisters()) {
+    GenerateRegisterArgsPush(masm);
+  }
+
+  // Left and right arguments are already on stack.
+  __ pop(rcx);  // Save the return address.
+
+  // Push this stub's key.
+  __ Push(Smi::FromInt(MinorKey()));
+
+  // Although the operation and the type info are encoded into the key,
+  // the encoding is opaque, so push them too.
+  __ Push(Smi::FromInt(op_));
+
+  __ Push(Smi::FromInt(runtime_operands_type_));
+
+  __ push(rcx);  // The return address.
+
+  // Perform patching to an appropriate fast case and return the result.
+  __ TailCallExternalReference(
+      ExternalReference(IC_Utility(IC::kBinaryOp_Patch)),
+      5,
+      1);
+}
+
+
+Handle<Code> GetBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info) {
+  GenericBinaryOpStub stub(key, type_info);
+  return stub.GetCode();
+}
+
+
+void TranscendentalCacheStub::Generate(MacroAssembler* masm) {
+  // Input on stack:
+  // rsp[8]: argument (should be number).
+  // rsp[0]: return address.
+  Label runtime_call;
+  Label runtime_call_clear_stack;
+  Label input_not_smi;
+  Label loaded;
+  // Test that rax is a number.
+  __ movq(rax, Operand(rsp, kPointerSize));
+  __ JumpIfNotSmi(rax, &input_not_smi);
+  // Input is a smi. Untag and load it onto the FPU stack.
+  // Then load the bits of the double into rbx.
+  __ SmiToInteger32(rax, rax);
+  __ subq(rsp, Immediate(kPointerSize));
+  __ cvtlsi2sd(xmm1, rax);
+  __ movsd(Operand(rsp, 0), xmm1);
+  __ movq(rbx, xmm1);
+  __ movq(rdx, xmm1);
+  __ fld_d(Operand(rsp, 0));
+  __ addq(rsp, Immediate(kPointerSize));
+  __ jmp(&loaded);
+
+  __ bind(&input_not_smi);
+  // Check if input is a HeapNumber.
+  __ Move(rbx, Factory::heap_number_map());
+  __ cmpq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
+  __ j(not_equal, &runtime_call);
+  // Input is a HeapNumber. Push it on the FPU stack and load its
+  // bits into rbx.
+  __ fld_d(FieldOperand(rax, HeapNumber::kValueOffset));
+  __ movq(rbx, FieldOperand(rax, HeapNumber::kValueOffset));
+  __ movq(rdx, rbx);
+  __ bind(&loaded);
+  // ST[0] == double value
+  // rbx = bits of double value.
+  // rdx = also bits of double value.
+  // Compute hash (h is 32 bits, bits are 64 and the shifts are arithmetic):
+  //   h = h0 = bits ^ (bits >> 32);
+  //   h ^= h >> 16;
+  //   h ^= h >> 8;
+  //   h = h & (cacheSize - 1);
+  // or h = (h0 ^ (h0 >> 8) ^ (h0 >> 16) ^ (h0 >> 24)) & (cacheSize - 1)
+  __ sar(rdx, Immediate(32));
+  __ xorl(rdx, rbx);
+  __ movl(rcx, rdx);
+  __ movl(rax, rdx);
+  __ movl(rdi, rdx);
+  __ sarl(rdx, Immediate(8));
+  __ sarl(rcx, Immediate(16));
+  __ sarl(rax, Immediate(24));
+  __ xorl(rcx, rdx);
+  __ xorl(rax, rdi);
+  __ xorl(rcx, rax);
+  ASSERT(IsPowerOf2(TranscendentalCache::kCacheSize));
+  __ andl(rcx, Immediate(TranscendentalCache::kCacheSize - 1));
+
+  // ST[0] == double value.
+  // rbx = bits of double value.
+  // rcx = TranscendentalCache::hash(double value).
+  __ movq(rax, ExternalReference::transcendental_cache_array_address());
+  // rax points to cache array.
+  __ movq(rax, Operand(rax, type_ * sizeof(TranscendentalCache::caches_[0])));
+  // rax points to the cache for the type type_.
+  // If NULL, the cache hasn't been initialized yet, so go through runtime.
+  __ testq(rax, rax);
+  __ j(zero, &runtime_call_clear_stack);
+#ifdef DEBUG
+  // Check that the layout of cache elements match expectations.
+  {  // NOLINT - doesn't like a single brace on a line.
+    TranscendentalCache::Element test_elem[2];
+    char* elem_start = reinterpret_cast<char*>(&test_elem[0]);
+    char* elem2_start = reinterpret_cast<char*>(&test_elem[1]);
+    char* elem_in0  = reinterpret_cast<char*>(&(test_elem[0].in[0]));
+    char* elem_in1  = reinterpret_cast<char*>(&(test_elem[0].in[1]));
+    char* elem_out = reinterpret_cast<char*>(&(test_elem[0].output));
+    // Two uint_32's and a pointer per element.
+    CHECK_EQ(16, static_cast<int>(elem2_start - elem_start));
+    CHECK_EQ(0, static_cast<int>(elem_in0 - elem_start));
+    CHECK_EQ(kIntSize, static_cast<int>(elem_in1 - elem_start));
+    CHECK_EQ(2 * kIntSize, static_cast<int>(elem_out - elem_start));
+  }
+#endif
+  // Find the address of the rcx'th entry in the cache, i.e., &rax[rcx*16].
+  __ addl(rcx, rcx);
+  __ lea(rcx, Operand(rax, rcx, times_8, 0));
+  // Check if cache matches: Double value is stored in uint32_t[2] array.
+  Label cache_miss;
+  __ cmpq(rbx, Operand(rcx, 0));
+  __ j(not_equal, &cache_miss);
+  // Cache hit!
+  __ movq(rax, Operand(rcx, 2 * kIntSize));
+  __ fstp(0);  // Clear FPU stack.
+  __ ret(kPointerSize);
+
+  __ bind(&cache_miss);
+  // Update cache with new value.
+  Label nan_result;
+  GenerateOperation(masm, &nan_result);
+  __ AllocateHeapNumber(rax, rdi, &runtime_call_clear_stack);
+  __ movq(Operand(rcx, 0), rbx);
+  __ movq(Operand(rcx, 2 * kIntSize), rax);
+  __ fstp_d(FieldOperand(rax, HeapNumber::kValueOffset));
+  __ ret(kPointerSize);
+
+  __ bind(&runtime_call_clear_stack);
+  __ fstp(0);
+  __ bind(&runtime_call);
+  __ TailCallExternalReference(ExternalReference(RuntimeFunction()), 1, 1);
+
+  __ bind(&nan_result);
+  __ fstp(0);  // Remove argument from FPU stack.
+  __ LoadRoot(rax, Heap::kNanValueRootIndex);
+  __ movq(Operand(rcx, 0), rbx);
+  __ movq(Operand(rcx, 2 * kIntSize), rax);
+  __ ret(kPointerSize);
+}
+
+
+Runtime::FunctionId TranscendentalCacheStub::RuntimeFunction() {
+  switch (type_) {
+    // Add more cases when necessary.
+    case TranscendentalCache::SIN: return Runtime::kMath_sin;
+    case TranscendentalCache::COS: return Runtime::kMath_cos;
+    default:
+      UNIMPLEMENTED();
+      return Runtime::kAbort;
+  }
+}
+
+
+void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm,
+                                                Label* on_nan_result) {
+  // Registers:
+  // rbx: Bits of input double. Must be preserved.
+  // rcx: Pointer to cache entry. Must be preserved.
+  // st(0): Input double
+  Label done;
+  ASSERT(type_ == TranscendentalCache::SIN ||
+         type_ == TranscendentalCache::COS);
+  // More transcendental types can be added later.
+
+  // Both fsin and fcos require arguments in the range +/-2^63 and
+  // return NaN for infinities and NaN. They can share all code except
+  // the actual fsin/fcos operation.
+  Label in_range;
+  // If argument is outside the range -2^63..2^63, fsin/cos doesn't
+  // work. We must reduce it to the appropriate range.
+  __ movq(rdi, rbx);
+  // Move exponent and sign bits to low bits.
+  __ shr(rdi, Immediate(HeapNumber::kMantissaBits));
+  // Remove sign bit.
+  __ andl(rdi, Immediate((1 << HeapNumber::kExponentBits) - 1));
+  int supported_exponent_limit = (63 + HeapNumber::kExponentBias);
+  __ cmpl(rdi, Immediate(supported_exponent_limit));
+  __ j(below, &in_range);
+  // Check for infinity and NaN. Both return NaN for sin.
+  __ cmpl(rdi, Immediate(0x7ff));
+  __ j(equal, on_nan_result);
+
+  // Use fpmod to restrict argument to the range +/-2*PI.
+  __ fldpi();
+  __ fadd(0);
+  __ fld(1);
+  // FPU Stack: input, 2*pi, input.
+  {
+    Label no_exceptions;
+    __ fwait();
+    __ fnstsw_ax();
+    // Clear if Illegal Operand or Zero Division exceptions are set.
+    __ testl(rax, Immediate(5));  // #IO and #ZD flags of FPU status word.
+    __ j(zero, &no_exceptions);
+    __ fnclex();
+    __ bind(&no_exceptions);
+  }
+
+  // Compute st(0) % st(1)
+  {
+    Label partial_remainder_loop;
+    __ bind(&partial_remainder_loop);
+    __ fprem1();
+    __ fwait();
+    __ fnstsw_ax();
+    __ testl(rax, Immediate(0x400));  // Check C2 bit of FPU status word.
+    // If C2 is set, computation only has partial result. Loop to
+    // continue computation.
+    __ j(not_zero, &partial_remainder_loop);
+  }
+  // FPU Stack: input, 2*pi, input % 2*pi
+  __ fstp(2);
+  // FPU Stack: input % 2*pi, 2*pi,
+  __ fstp(0);
+  // FPU Stack: input % 2*pi
+  __ bind(&in_range);
+  switch (type_) {
+    case TranscendentalCache::SIN:
+      __ fsin();
+      break;
+    case TranscendentalCache::COS:
+      __ fcos();
+      break;
+    default:
+      UNREACHABLE();
+  }
+  __ bind(&done);
+}
+
+
+// Get the integer part of a heap number.
+// Overwrites the contents of rdi, rbx and rcx. Result cannot be rdi or rbx.
+void IntegerConvert(MacroAssembler* masm,
+                    Register result,
+                    Register source) {
+  // Result may be rcx. If result and source are the same register, source will
+  // be overwritten.
+  ASSERT(!result.is(rdi) && !result.is(rbx));
+  // TODO(lrn): When type info reaches here, if value is a 32-bit integer, use
+  // cvttsd2si (32-bit version) directly.
+  Register double_exponent = rbx;
+  Register double_value = rdi;
+  Label done, exponent_63_plus;
+  // Get double and extract exponent.
+  __ movq(double_value, FieldOperand(source, HeapNumber::kValueOffset));
+  // Clear result preemptively, in case we need to return zero.
+  __ xorl(result, result);
+  __ movq(xmm0, double_value);  // Save copy in xmm0 in case we need it there.
+  // Double to remove sign bit, shift exponent down to least significant bits.
+  // and subtract bias to get the unshifted, unbiased exponent.
+  __ lea(double_exponent, Operand(double_value, double_value, times_1, 0));
+  __ shr(double_exponent, Immediate(64 - HeapNumber::kExponentBits));
+  __ subl(double_exponent, Immediate(HeapNumber::kExponentBias));
+  // Check whether the exponent is too big for a 63 bit unsigned integer.
+  __ cmpl(double_exponent, Immediate(63));
+  __ j(above_equal, &exponent_63_plus);
+  // Handle exponent range 0..62.
+  __ cvttsd2siq(result, xmm0);
+  __ jmp(&done);
+
+  __ bind(&exponent_63_plus);
+  // Exponent negative or 63+.
+  __ cmpl(double_exponent, Immediate(83));
+  // If exponent negative or above 83, number contains no significant bits in
+  // the range 0..2^31, so result is zero, and rcx already holds zero.
+  __ j(above, &done);
+
+  // Exponent in rage 63..83.
+  // Mantissa * 2^exponent contains bits in the range 2^0..2^31, namely
+  // the least significant exponent-52 bits.
+
+  // Negate low bits of mantissa if value is negative.
+  __ addq(double_value, double_value);  // Move sign bit to carry.
+  __ sbbl(result, result);  // And convert carry to -1 in result register.
+  // if scratch2 is negative, do (scratch2-1)^-1, otherwise (scratch2-0)^0.
+  __ addl(double_value, result);
+  // Do xor in opposite directions depending on where we want the result
+  // (depending on whether result is rcx or not).
+
+  if (result.is(rcx)) {
+    __ xorl(double_value, result);
+    // Left shift mantissa by (exponent - mantissabits - 1) to save the
+    // bits that have positional values below 2^32 (the extra -1 comes from the
+    // doubling done above to move the sign bit into the carry flag).
+    __ leal(rcx, Operand(double_exponent, -HeapNumber::kMantissaBits - 1));
+    __ shll_cl(double_value);
+    __ movl(result, double_value);
+  } else {
+    // As the then-branch, but move double-value to result before shifting.
+    __ xorl(result, double_value);
+    __ leal(rcx, Operand(double_exponent, -HeapNumber::kMantissaBits - 1));
+    __ shll_cl(result);
+  }
+
+  __ bind(&done);
+}
+
+
+// Input: rdx, rax are the left and right objects of a bit op.
+// Output: rax, rcx are left and right integers for a bit op.
+void FloatingPointHelper::LoadNumbersAsIntegers(MacroAssembler* masm) {
+  // Check float operands.
+  Label done;
+  Label rax_is_smi;
+  Label rax_is_object;
+  Label rdx_is_object;
+
+  __ JumpIfNotSmi(rdx, &rdx_is_object);
+  __ SmiToInteger32(rdx, rdx);
+  __ JumpIfSmi(rax, &rax_is_smi);
+
+  __ bind(&rax_is_object);
+  IntegerConvert(masm, rcx, rax);  // Uses rdi, rcx and rbx.
+  __ jmp(&done);
+
+  __ bind(&rdx_is_object);
+  IntegerConvert(masm, rdx, rdx);  // Uses rdi, rcx and rbx.
+  __ JumpIfNotSmi(rax, &rax_is_object);
+  __ bind(&rax_is_smi);
+  __ SmiToInteger32(rcx, rax);
+
+  __ bind(&done);
+  __ movl(rax, rdx);
+}
+
+
+// Input: rdx, rax are the left and right objects of a bit op.
+// Output: rax, rcx are left and right integers for a bit op.
+void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
+                                         Label* conversion_failure,
+                                         Register heap_number_map) {
+  // Check float operands.
+  Label arg1_is_object, check_undefined_arg1;
+  Label arg2_is_object, check_undefined_arg2;
+  Label load_arg2, done;
+
+  __ JumpIfNotSmi(rdx, &arg1_is_object);
+  __ SmiToInteger32(rdx, rdx);
+  __ jmp(&load_arg2);
+
+  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
+  __ bind(&check_undefined_arg1);
+  __ CompareRoot(rdx, Heap::kUndefinedValueRootIndex);
+  __ j(not_equal, conversion_failure);
+  __ movl(rdx, Immediate(0));
+  __ jmp(&load_arg2);
+
+  __ bind(&arg1_is_object);
+  __ cmpq(FieldOperand(rdx, HeapObject::kMapOffset), heap_number_map);
+  __ j(not_equal, &check_undefined_arg1);
+  // Get the untagged integer version of the edx heap number in rcx.
+  IntegerConvert(masm, rdx, rdx);
+
+  // Here rdx has the untagged integer, rax has a Smi or a heap number.
+  __ bind(&load_arg2);
+  // Test if arg2 is a Smi.
+  __ JumpIfNotSmi(rax, &arg2_is_object);
+  __ SmiToInteger32(rax, rax);
+  __ movl(rcx, rax);
+  __ jmp(&done);
+
+  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
+  __ bind(&check_undefined_arg2);
+  __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
+  __ j(not_equal, conversion_failure);
+  __ movl(rcx, Immediate(0));
+  __ jmp(&done);
+
+  __ bind(&arg2_is_object);
+  __ cmpq(FieldOperand(rax, HeapObject::kMapOffset), heap_number_map);
+  __ j(not_equal, &check_undefined_arg2);
+  // Get the untagged integer version of the rax heap number in rcx.
+  IntegerConvert(masm, rcx, rax);
+  __ bind(&done);
+  __ movl(rax, rdx);
+}
+
+
+void FloatingPointHelper::LoadSSE2SmiOperands(MacroAssembler* masm) {
+  __ SmiToInteger32(kScratchRegister, rdx);
+  __ cvtlsi2sd(xmm0, kScratchRegister);
+  __ SmiToInteger32(kScratchRegister, rax);
+  __ cvtlsi2sd(xmm1, kScratchRegister);
+}
+
+
+void FloatingPointHelper::LoadSSE2NumberOperands(MacroAssembler* masm) {
+  Label load_smi_rdx, load_nonsmi_rax, load_smi_rax, done;
+  // Load operand in rdx into xmm0.
+  __ JumpIfSmi(rdx, &load_smi_rdx);
+  __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+  // Load operand in rax into xmm1.
+  __ JumpIfSmi(rax, &load_smi_rax);
+  __ bind(&load_nonsmi_rax);
+  __ movsd(xmm1, FieldOperand(rax, HeapNumber::kValueOffset));
+  __ jmp(&done);
+
+  __ bind(&load_smi_rdx);
+  __ SmiToInteger32(kScratchRegister, rdx);
+  __ cvtlsi2sd(xmm0, kScratchRegister);
+  __ JumpIfNotSmi(rax, &load_nonsmi_rax);
+
+  __ bind(&load_smi_rax);
+  __ SmiToInteger32(kScratchRegister, rax);
+  __ cvtlsi2sd(xmm1, kScratchRegister);
+
+  __ bind(&done);
+}
+
+
+void FloatingPointHelper::LoadSSE2UnknownOperands(MacroAssembler* masm,
+                                                  Label* not_numbers) {
+  Label load_smi_rdx, load_nonsmi_rax, load_smi_rax, load_float_rax, done;
+  // Load operand in rdx into xmm0, or branch to not_numbers.
+  __ LoadRoot(rcx, Heap::kHeapNumberMapRootIndex);
+  __ JumpIfSmi(rdx, &load_smi_rdx);
+  __ cmpq(FieldOperand(rdx, HeapObject::kMapOffset), rcx);
+  __ j(not_equal, not_numbers);  // Argument in rdx is not a number.
+  __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+  // Load operand in rax into xmm1, or branch to not_numbers.
+  __ JumpIfSmi(rax, &load_smi_rax);
+
+  __ bind(&load_nonsmi_rax);
+  __ cmpq(FieldOperand(rax, HeapObject::kMapOffset), rcx);
+  __ j(not_equal, not_numbers);
+  __ movsd(xmm1, FieldOperand(rax, HeapNumber::kValueOffset));
+  __ jmp(&done);
+
+  __ bind(&load_smi_rdx);
+  __ SmiToInteger32(kScratchRegister, rdx);
+  __ cvtlsi2sd(xmm0, kScratchRegister);
+  __ JumpIfNotSmi(rax, &load_nonsmi_rax);
+
+  __ bind(&load_smi_rax);
+  __ SmiToInteger32(kScratchRegister, rax);
+  __ cvtlsi2sd(xmm1, kScratchRegister);
+  __ bind(&done);
+}
+
+
+void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
+  Label slow, done;
+
+  if (op_ == Token::SUB) {
+    // Check whether the value is a smi.
+    Label try_float;
+    __ JumpIfNotSmi(rax, &try_float);
+
+    if (negative_zero_ == kIgnoreNegativeZero) {
+      __ SmiCompare(rax, Smi::FromInt(0));
+      __ j(equal, &done);
+    }
+
+    // Enter runtime system if the value of the smi is zero
+    // to make sure that we switch between 0 and -0.
+    // Also enter it if the value of the smi is Smi::kMinValue.
+    __ SmiNeg(rax, rax, &done);
+
+    // Either zero or Smi::kMinValue, neither of which become a smi when
+    // negated.
+    if (negative_zero_ == kStrictNegativeZero) {
+      __ SmiCompare(rax, Smi::FromInt(0));
+      __ j(not_equal, &slow);
+      __ Move(rax, Factory::minus_zero_value());
+      __ jmp(&done);
+    } else  {
+      __ jmp(&slow);
+    }
+
+    // Try floating point case.
+    __ bind(&try_float);
+    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
+    __ j(not_equal, &slow);
+    // Operand is a float, negate its value by flipping sign bit.
+    __ movq(rdx, FieldOperand(rax, HeapNumber::kValueOffset));
+    __ movq(kScratchRegister, Immediate(0x01));
+    __ shl(kScratchRegister, Immediate(63));
+    __ xor_(rdx, kScratchRegister);  // Flip sign.
+    // rdx is value to store.
+    if (overwrite_ == UNARY_OVERWRITE) {
+      __ movq(FieldOperand(rax, HeapNumber::kValueOffset), rdx);
+    } else {
+      __ AllocateHeapNumber(rcx, rbx, &slow);
+      // rcx: allocated 'empty' number
+      __ movq(FieldOperand(rcx, HeapNumber::kValueOffset), rdx);
+      __ movq(rax, rcx);
+    }
+  } else if (op_ == Token::BIT_NOT) {
+    // Check if the operand is a heap number.
+    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
+    __ j(not_equal, &slow);
+
+    // Convert the heap number in rax to an untagged integer in rcx.
+    IntegerConvert(masm, rax, rax);
+
+    // Do the bitwise operation and smi tag the result.
+    __ notl(rax);
+    __ Integer32ToSmi(rax, rax);
+  }
+
+  // Return from the stub.
+  __ bind(&done);
+  __ StubReturn(1);
+
+  // Handle the slow case by jumping to the JavaScript builtin.
+  __ bind(&slow);
+  __ pop(rcx);  // pop return address
+  __ push(rax);
+  __ push(rcx);  // push return address
+  switch (op_) {
+    case Token::SUB:
+      __ InvokeBuiltin(Builtins::UNARY_MINUS, JUMP_FUNCTION);
+      break;
+    case Token::BIT_NOT:
+      __ InvokeBuiltin(Builtins::BIT_NOT, JUMP_FUNCTION);
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
+  // The key is in rdx and the parameter count is in rax.
+
+  // The displacement is used for skipping the frame pointer on the
+  // stack. It is the offset of the last parameter (if any) relative
+  // to the frame pointer.
+  static const int kDisplacement = 1 * kPointerSize;
+
+  // Check that the key is a smi.
+  Label slow;
+  __ JumpIfNotSmi(rdx, &slow);
+
+  // Check if the calling frame is an arguments adaptor frame.
+  Label adaptor;
+  __ movq(rbx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+  __ SmiCompare(Operand(rbx, StandardFrameConstants::kContextOffset),
+                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  __ j(equal, &adaptor);
+
+  // Check index against formal parameters count limit passed in
+  // through register rax. Use unsigned comparison to get negative
+  // check for free.
+  __ cmpq(rdx, rax);
+  __ j(above_equal, &slow);
+
+  // Read the argument from the stack and return it.
+  SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
+  __ lea(rbx, Operand(rbp, index.reg, index.scale, 0));
+  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
+  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
+  __ Ret();
+
+  // Arguments adaptor case: Check index against actual arguments
+  // limit found in the arguments adaptor frame. Use unsigned
+  // comparison to get negative check for free.
+  __ bind(&adaptor);
+  __ movq(rcx, Operand(rbx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  __ cmpq(rdx, rcx);
+  __ j(above_equal, &slow);
+
+  // Read the argument from the stack and return it.
+  index = masm->SmiToIndex(rax, rcx, kPointerSizeLog2);
+  __ lea(rbx, Operand(rbx, index.reg, index.scale, 0));
+  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
+  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
+  __ Ret();
+
+  // Slow-case: Handle non-smi or out-of-bounds access to arguments
+  // by calling the runtime system.
+  __ bind(&slow);
+  __ pop(rbx);  // Return address.
+  __ push(rdx);
+  __ push(rbx);
+  __ TailCallRuntime(Runtime::kGetArgumentsProperty, 1, 1);
+}
+
+
+void ArgumentsAccessStub::GenerateNewObject(MacroAssembler* masm) {
+  // rsp[0] : return address
+  // rsp[8] : number of parameters
+  // rsp[16] : receiver displacement
+  // rsp[24] : function
+
+  // The displacement is used for skipping the return address and the
+  // frame pointer on the stack. It is the offset of the last
+  // parameter (if any) relative to the frame pointer.
+  static const int kDisplacement = 2 * kPointerSize;
+
+  // Check if the calling frame is an arguments adaptor frame.
+  Label adaptor_frame, try_allocate, runtime;
+  __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+  __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
+                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  __ j(equal, &adaptor_frame);
+
+  // Get the length from the frame.
+  __ SmiToInteger32(rcx, Operand(rsp, 1 * kPointerSize));
+  __ jmp(&try_allocate);
+
+  // Patch the arguments.length and the parameters pointer.
+  __ bind(&adaptor_frame);
+  __ SmiToInteger32(rcx,
+                    Operand(rdx,
+                            ArgumentsAdaptorFrameConstants::kLengthOffset));
+  // Space on stack must already hold a smi.
+  __ Integer32ToSmiField(Operand(rsp, 1 * kPointerSize), rcx);
+  // Do not clobber the length index for the indexing operation since
+  // it is used compute the size for allocation later.
+  __ lea(rdx, Operand(rdx, rcx, times_pointer_size, kDisplacement));
+  __ movq(Operand(rsp, 2 * kPointerSize), rdx);
+
+  // Try the new space allocation. Start out with computing the size of
+  // the arguments object and the elements array.
+  Label add_arguments_object;
+  __ bind(&try_allocate);
+  __ testl(rcx, rcx);
+  __ j(zero, &add_arguments_object);
+  __ leal(rcx, Operand(rcx, times_pointer_size, FixedArray::kHeaderSize));
+  __ bind(&add_arguments_object);
+  __ addl(rcx, Immediate(Heap::kArgumentsObjectSize));
+
+  // Do the allocation of both objects in one go.
+  __ AllocateInNewSpace(rcx, rax, rdx, rbx, &runtime, TAG_OBJECT);
+
+  // Get the arguments boilerplate from the current (global) context.
+  int offset = Context::SlotOffset(Context::ARGUMENTS_BOILERPLATE_INDEX);
+  __ movq(rdi, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(rdi, FieldOperand(rdi, GlobalObject::kGlobalContextOffset));
+  __ movq(rdi, Operand(rdi, offset));
+
+  // Copy the JS object part.
+  STATIC_ASSERT(JSObject::kHeaderSize == 3 * kPointerSize);
+  __ movq(kScratchRegister, FieldOperand(rdi, 0 * kPointerSize));
+  __ movq(rdx, FieldOperand(rdi, 1 * kPointerSize));
+  __ movq(rbx, FieldOperand(rdi, 2 * kPointerSize));
+  __ movq(FieldOperand(rax, 0 * kPointerSize), kScratchRegister);
+  __ movq(FieldOperand(rax, 1 * kPointerSize), rdx);
+  __ movq(FieldOperand(rax, 2 * kPointerSize), rbx);
+
+  // Setup the callee in-object property.
+  ASSERT(Heap::arguments_callee_index == 0);
+  __ movq(kScratchRegister, Operand(rsp, 3 * kPointerSize));
+  __ movq(FieldOperand(rax, JSObject::kHeaderSize), kScratchRegister);
+
+  // Get the length (smi tagged) and set that as an in-object property too.
+  ASSERT(Heap::arguments_length_index == 1);
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+  __ movq(FieldOperand(rax, JSObject::kHeaderSize + kPointerSize), rcx);
+
+  // If there are no actual arguments, we're done.
+  Label done;
+  __ SmiTest(rcx);
+  __ j(zero, &done);
+
+  // Get the parameters pointer from the stack and untag the length.
+  __ movq(rdx, Operand(rsp, 2 * kPointerSize));
+
+  // Setup the elements pointer in the allocated arguments object and
+  // initialize the header in the elements fixed array.
+  __ lea(rdi, Operand(rax, Heap::kArgumentsObjectSize));
+  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rdi);
+  __ LoadRoot(kScratchRegister, Heap::kFixedArrayMapRootIndex);
+  __ movq(FieldOperand(rdi, FixedArray::kMapOffset), kScratchRegister);
+  __ movq(FieldOperand(rdi, FixedArray::kLengthOffset), rcx);
+  __ SmiToInteger32(rcx, rcx);  // Untag length for the loop below.
+
+  // Copy the fixed array slots.
+  Label loop;
+  __ bind(&loop);
+  __ movq(kScratchRegister, Operand(rdx, -1 * kPointerSize));  // Skip receiver.
+  __ movq(FieldOperand(rdi, FixedArray::kHeaderSize), kScratchRegister);
+  __ addq(rdi, Immediate(kPointerSize));
+  __ subq(rdx, Immediate(kPointerSize));
+  __ decl(rcx);
+  __ j(not_zero, &loop);
+
+  // Return and remove the on-stack parameters.
+  __ bind(&done);
+  __ ret(3 * kPointerSize);
+
+  // Do the runtime call to allocate the arguments object.
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kNewArgumentsFast, 3, 1);
+}
+
+
+void RegExpExecStub::Generate(MacroAssembler* masm) {
+  // Just jump directly to runtime if native RegExp is not selected at compile
+  // time or if regexp entry in generated code is turned off runtime switch or
+  // at compilation.
+#ifdef V8_INTERPRETED_REGEXP
+  __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
+#else  // V8_INTERPRETED_REGEXP
+  if (!FLAG_regexp_entry_native) {
+    __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
+    return;
+  }
+
+  // Stack frame on entry.
+  //  esp[0]: return address
+  //  esp[8]: last_match_info (expected JSArray)
+  //  esp[16]: previous index
+  //  esp[24]: subject string
+  //  esp[32]: JSRegExp object
+
+  static const int kLastMatchInfoOffset = 1 * kPointerSize;
+  static const int kPreviousIndexOffset = 2 * kPointerSize;
+  static const int kSubjectOffset = 3 * kPointerSize;
+  static const int kJSRegExpOffset = 4 * kPointerSize;
+
+  Label runtime;
+
+  // Ensure that a RegExp stack is allocated.
+  ExternalReference address_of_regexp_stack_memory_address =
+      ExternalReference::address_of_regexp_stack_memory_address();
+  ExternalReference address_of_regexp_stack_memory_size =
+      ExternalReference::address_of_regexp_stack_memory_size();
+  __ movq(kScratchRegister, address_of_regexp_stack_memory_size);
+  __ movq(kScratchRegister, Operand(kScratchRegister, 0));
+  __ testq(kScratchRegister, kScratchRegister);
+  __ j(zero, &runtime);
+
+
+  // Check that the first argument is a JSRegExp object.
+  __ movq(rax, Operand(rsp, kJSRegExpOffset));
+  __ JumpIfSmi(rax, &runtime);
+  __ CmpObjectType(rax, JS_REGEXP_TYPE, kScratchRegister);
+  __ j(not_equal, &runtime);
+  // Check that the RegExp has been compiled (data contains a fixed array).
+  __ movq(rcx, FieldOperand(rax, JSRegExp::kDataOffset));
+  if (FLAG_debug_code) {
+    Condition is_smi = masm->CheckSmi(rcx);
+    __ Check(NegateCondition(is_smi),
+        "Unexpected type for RegExp data, FixedArray expected");
+    __ CmpObjectType(rcx, FIXED_ARRAY_TYPE, kScratchRegister);
+    __ Check(equal, "Unexpected type for RegExp data, FixedArray expected");
+  }
+
+  // rcx: RegExp data (FixedArray)
+  // Check the type of the RegExp. Only continue if type is JSRegExp::IRREGEXP.
+  __ SmiToInteger32(rbx, FieldOperand(rcx, JSRegExp::kDataTagOffset));
+  __ cmpl(rbx, Immediate(JSRegExp::IRREGEXP));
+  __ j(not_equal, &runtime);
+
+  // rcx: RegExp data (FixedArray)
+  // Check that the number of captures fit in the static offsets vector buffer.
+  __ SmiToInteger32(rdx,
+                    FieldOperand(rcx, JSRegExp::kIrregexpCaptureCountOffset));
+  // Calculate number of capture registers (number_of_captures + 1) * 2.
+  __ leal(rdx, Operand(rdx, rdx, times_1, 2));
+  // Check that the static offsets vector buffer is large enough.
+  __ cmpl(rdx, Immediate(OffsetsVector::kStaticOffsetsVectorSize));
+  __ j(above, &runtime);
+
+  // rcx: RegExp data (FixedArray)
+  // rdx: Number of capture registers
+  // Check that the second argument is a string.
+  __ movq(rax, Operand(rsp, kSubjectOffset));
+  __ JumpIfSmi(rax, &runtime);
+  Condition is_string = masm->IsObjectStringType(rax, rbx, rbx);
+  __ j(NegateCondition(is_string), &runtime);
+
+  // rax: Subject string.
+  // rcx: RegExp data (FixedArray).
+  // rdx: Number of capture registers.
+  // Check that the third argument is a positive smi less than the string
+  // length. A negative value will be greater (unsigned comparison).
+  __ movq(rbx, Operand(rsp, kPreviousIndexOffset));
+  __ JumpIfNotSmi(rbx, &runtime);
+  __ SmiCompare(rbx, FieldOperand(rax, String::kLengthOffset));
+  __ j(above_equal, &runtime);
+
+  // rcx: RegExp data (FixedArray)
+  // rdx: Number of capture registers
+  // Check that the fourth object is a JSArray object.
+  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
+  __ JumpIfSmi(rax, &runtime);
+  __ CmpObjectType(rax, JS_ARRAY_TYPE, kScratchRegister);
+  __ j(not_equal, &runtime);
+  // Check that the JSArray is in fast case.
+  __ movq(rbx, FieldOperand(rax, JSArray::kElementsOffset));
+  __ movq(rax, FieldOperand(rbx, HeapObject::kMapOffset));
+  __ Cmp(rax, Factory::fixed_array_map());
+  __ j(not_equal, &runtime);
+  // Check that the last match info has space for the capture registers and the
+  // additional information. Ensure no overflow in add.
+  STATIC_ASSERT(FixedArray::kMaxLength < kMaxInt - FixedArray::kLengthOffset);
+  __ SmiToInteger32(rax, FieldOperand(rbx, FixedArray::kLengthOffset));
+  __ addl(rdx, Immediate(RegExpImpl::kLastMatchOverhead));
+  __ cmpl(rdx, rax);
+  __ j(greater, &runtime);
+
+  // rcx: RegExp data (FixedArray)
+  // Check the representation and encoding of the subject string.
+  Label seq_ascii_string, seq_two_byte_string, check_code;
+  __ movq(rax, Operand(rsp, kSubjectOffset));
+  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
+  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
+  // First check for flat two byte string.
+  __ andb(rbx, Immediate(
+      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask));
+  STATIC_ASSERT((kStringTag | kSeqStringTag | kTwoByteStringTag) == 0);
+  __ j(zero, &seq_two_byte_string);
+  // Any other flat string must be a flat ascii string.
+  __ testb(rbx, Immediate(kIsNotStringMask | kStringRepresentationMask));
+  __ j(zero, &seq_ascii_string);
+
+  // Check for flat cons string.
+  // A flat cons string is a cons string where the second part is the empty
+  // string. In that case the subject string is just the first part of the cons
+  // string. Also in this case the first part of the cons string is known to be
+  // a sequential string or an external string.
+  STATIC_ASSERT(kExternalStringTag !=0);
+  STATIC_ASSERT((kConsStringTag & kExternalStringTag) == 0);
+  __ testb(rbx, Immediate(kIsNotStringMask | kExternalStringTag));
+  __ j(not_zero, &runtime);
+  // String is a cons string.
+  __ movq(rdx, FieldOperand(rax, ConsString::kSecondOffset));
+  __ Cmp(rdx, Factory::empty_string());
+  __ j(not_equal, &runtime);
+  __ movq(rax, FieldOperand(rax, ConsString::kFirstOffset));
+  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
+  // String is a cons string with empty second part.
+  // rax: first part of cons string.
+  // rbx: map of first part of cons string.
+  // Is first part a flat two byte string?
+  __ testb(FieldOperand(rbx, Map::kInstanceTypeOffset),
+           Immediate(kStringRepresentationMask | kStringEncodingMask));
+  STATIC_ASSERT((kSeqStringTag | kTwoByteStringTag) == 0);
+  __ j(zero, &seq_two_byte_string);
+  // Any other flat string must be ascii.
+  __ testb(FieldOperand(rbx, Map::kInstanceTypeOffset),
+           Immediate(kStringRepresentationMask));
+  __ j(not_zero, &runtime);
+
+  __ bind(&seq_ascii_string);
+  // rax: subject string (sequential ascii)
+  // rcx: RegExp data (FixedArray)
+  __ movq(r11, FieldOperand(rcx, JSRegExp::kDataAsciiCodeOffset));
+  __ Set(rdi, 1);  // Type is ascii.
+  __ jmp(&check_code);
+
+  __ bind(&seq_two_byte_string);
+  // rax: subject string (flat two-byte)
+  // rcx: RegExp data (FixedArray)
+  __ movq(r11, FieldOperand(rcx, JSRegExp::kDataUC16CodeOffset));
+  __ Set(rdi, 0);  // Type is two byte.
+
+  __ bind(&check_code);
+  // Check that the irregexp code has been generated for the actual string
+  // encoding. If it has, the field contains a code object otherwise it contains
+  // the hole.
+  __ CmpObjectType(r11, CODE_TYPE, kScratchRegister);
+  __ j(not_equal, &runtime);
+
+  // rax: subject string
+  // rdi: encoding of subject string (1 if ascii, 0 if two_byte);
+  // r11: code
+  // Load used arguments before starting to push arguments for call to native
+  // RegExp code to avoid handling changing stack height.
+  __ SmiToInteger64(rbx, Operand(rsp, kPreviousIndexOffset));
+
+  // rax: subject string
+  // rbx: previous index
+  // rdi: encoding of subject string (1 if ascii 0 if two_byte);
+  // r11: code
+  // All checks done. Now push arguments for native regexp code.
+  __ IncrementCounter(&Counters::regexp_entry_native, 1);
+
+  // rsi is caller save on Windows and used to pass parameter on Linux.
+  __ push(rsi);
+
+  static const int kRegExpExecuteArguments = 7;
+  __ PrepareCallCFunction(kRegExpExecuteArguments);
+  int argument_slots_on_stack =
+      masm->ArgumentStackSlotsForCFunctionCall(kRegExpExecuteArguments);
+
+  // Argument 7: Indicate that this is a direct call from JavaScript.
+  __ movq(Operand(rsp, (argument_slots_on_stack - 1) * kPointerSize),
+          Immediate(1));
+
+  // Argument 6: Start (high end) of backtracking stack memory area.
+  __ movq(kScratchRegister, address_of_regexp_stack_memory_address);
+  __ movq(r9, Operand(kScratchRegister, 0));
+  __ movq(kScratchRegister, address_of_regexp_stack_memory_size);
+  __ addq(r9, Operand(kScratchRegister, 0));
+  // Argument 6 passed in r9 on Linux and on the stack on Windows.
+#ifdef _WIN64
+  __ movq(Operand(rsp, (argument_slots_on_stack - 2) * kPointerSize), r9);
+#endif
+
+  // Argument 5: static offsets vector buffer.
+  __ movq(r8, ExternalReference::address_of_static_offsets_vector());
+  // Argument 5 passed in r8 on Linux and on the stack on Windows.
+#ifdef _WIN64
+  __ movq(Operand(rsp, (argument_slots_on_stack - 3) * kPointerSize), r8);
+#endif
+
+  // First four arguments are passed in registers on both Linux and Windows.
+#ifdef _WIN64
+  Register arg4 = r9;
+  Register arg3 = r8;
+  Register arg2 = rdx;
+  Register arg1 = rcx;
+#else
+  Register arg4 = rcx;
+  Register arg3 = rdx;
+  Register arg2 = rsi;
+  Register arg1 = rdi;
+#endif
+
+  // Keep track on aliasing between argX defined above and the registers used.
+  // rax: subject string
+  // rbx: previous index
+  // rdi: encoding of subject string (1 if ascii 0 if two_byte);
+  // r11: code
+
+  // Argument 4: End of string data
+  // Argument 3: Start of string data
+  Label setup_two_byte, setup_rest;
+  __ testb(rdi, rdi);
+  __ j(zero, &setup_two_byte);
+  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
+  __ lea(arg4, FieldOperand(rax, rdi, times_1, SeqAsciiString::kHeaderSize));
+  __ lea(arg3, FieldOperand(rax, rbx, times_1, SeqAsciiString::kHeaderSize));
+  __ jmp(&setup_rest);
+  __ bind(&setup_two_byte);
+  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
+  __ lea(arg4, FieldOperand(rax, rdi, times_2, SeqTwoByteString::kHeaderSize));
+  __ lea(arg3, FieldOperand(rax, rbx, times_2, SeqTwoByteString::kHeaderSize));
+
+  __ bind(&setup_rest);
+  // Argument 2: Previous index.
+  __ movq(arg2, rbx);
+
+  // Argument 1: Subject string.
+  __ movq(arg1, rax);
+
+  // Locate the code entry and call it.
+  __ addq(r11, Immediate(Code::kHeaderSize - kHeapObjectTag));
+  __ CallCFunction(r11, kRegExpExecuteArguments);
+
+  // rsi is caller save, as it is used to pass parameter.
+  __ pop(rsi);
+
+  // Check the result.
+  Label success;
+  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::SUCCESS));
+  __ j(equal, &success);
+  Label failure;
+  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::FAILURE));
+  __ j(equal, &failure);
+  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::EXCEPTION));
+  // If not exception it can only be retry. Handle that in the runtime system.
+  __ j(not_equal, &runtime);
+  // Result must now be exception. If there is no pending exception already a
+  // stack overflow (on the backtrack stack) was detected in RegExp code but
+  // haven't created the exception yet. Handle that in the runtime system.
+  // TODO(592): Rerunning the RegExp to get the stack overflow exception.
+  ExternalReference pending_exception_address(Top::k_pending_exception_address);
+  __ movq(kScratchRegister, pending_exception_address);
+  __ Cmp(kScratchRegister, Factory::the_hole_value());
+  __ j(equal, &runtime);
+  __ bind(&failure);
+  // For failure and exception return null.
+  __ Move(rax, Factory::null_value());
+  __ ret(4 * kPointerSize);
+
+  // Load RegExp data.
+  __ bind(&success);
+  __ movq(rax, Operand(rsp, kJSRegExpOffset));
+  __ movq(rcx, FieldOperand(rax, JSRegExp::kDataOffset));
+  __ SmiToInteger32(rax,
+                    FieldOperand(rcx, JSRegExp::kIrregexpCaptureCountOffset));
+  // Calculate number of capture registers (number_of_captures + 1) * 2.
+  __ leal(rdx, Operand(rax, rax, times_1, 2));
+
+  // rdx: Number of capture registers
+  // Load last_match_info which is still known to be a fast case JSArray.
+  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
+  __ movq(rbx, FieldOperand(rax, JSArray::kElementsOffset));
+
+  // rbx: last_match_info backing store (FixedArray)
+  // rdx: number of capture registers
+  // Store the capture count.
+  __ Integer32ToSmi(kScratchRegister, rdx);
+  __ movq(FieldOperand(rbx, RegExpImpl::kLastCaptureCountOffset),
+          kScratchRegister);
+  // Store last subject and last input.
+  __ movq(rax, Operand(rsp, kSubjectOffset));
+  __ movq(FieldOperand(rbx, RegExpImpl::kLastSubjectOffset), rax);
+  __ movq(rcx, rbx);
+  __ RecordWrite(rcx, RegExpImpl::kLastSubjectOffset, rax, rdi);
+  __ movq(rax, Operand(rsp, kSubjectOffset));
+  __ movq(FieldOperand(rbx, RegExpImpl::kLastInputOffset), rax);
+  __ movq(rcx, rbx);
+  __ RecordWrite(rcx, RegExpImpl::kLastInputOffset, rax, rdi);
+
+  // Get the static offsets vector filled by the native regexp code.
+  __ movq(rcx, ExternalReference::address_of_static_offsets_vector());
+
+  // rbx: last_match_info backing store (FixedArray)
+  // rcx: offsets vector
+  // rdx: number of capture registers
+  Label next_capture, done;
+  // Capture register counter starts from number of capture registers and
+  // counts down until wraping after zero.
+  __ bind(&next_capture);
+  __ subq(rdx, Immediate(1));
+  __ j(negative, &done);
+  // Read the value from the static offsets vector buffer and make it a smi.
+  __ movl(rdi, Operand(rcx, rdx, times_int_size, 0));
+  __ Integer32ToSmi(rdi, rdi, &runtime);
+  // Store the smi value in the last match info.
+  __ movq(FieldOperand(rbx,
+                       rdx,
+                       times_pointer_size,
+                       RegExpImpl::kFirstCaptureOffset),
+          rdi);
+  __ jmp(&next_capture);
+  __ bind(&done);
+
+  // Return last match info.
+  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
+  __ ret(4 * kPointerSize);
+
+  // Do the runtime call to execute the regexp.
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
+#endif  // V8_INTERPRETED_REGEXP
+}
+
+
+void NumberToStringStub::GenerateLookupNumberStringCache(MacroAssembler* masm,
+                                                         Register object,
+                                                         Register result,
+                                                         Register scratch1,
+                                                         Register scratch2,
+                                                         bool object_is_smi,
+                                                         Label* not_found) {
+  // Use of registers. Register result is used as a temporary.
+  Register number_string_cache = result;
+  Register mask = scratch1;
+  Register scratch = scratch2;
+
+  // Load the number string cache.
+  __ LoadRoot(number_string_cache, Heap::kNumberStringCacheRootIndex);
+
+  // Make the hash mask from the length of the number string cache. It
+  // contains two elements (number and string) for each cache entry.
+  __ SmiToInteger32(
+      mask, FieldOperand(number_string_cache, FixedArray::kLengthOffset));
+  __ shrl(mask, Immediate(1));
+  __ subq(mask, Immediate(1));  // Make mask.
+
+  // Calculate the entry in the number string cache. The hash value in the
+  // number string cache for smis is just the smi value, and the hash for
+  // doubles is the xor of the upper and lower words. See
+  // Heap::GetNumberStringCache.
+  Label is_smi;
+  Label load_result_from_cache;
+  if (!object_is_smi) {
+    __ JumpIfSmi(object, &is_smi);
+    __ CheckMap(object, Factory::heap_number_map(), not_found, true);
+
+    STATIC_ASSERT(8 == kDoubleSize);
+    __ movl(scratch, FieldOperand(object, HeapNumber::kValueOffset + 4));
+    __ xor_(scratch, FieldOperand(object, HeapNumber::kValueOffset));
+    GenerateConvertHashCodeToIndex(masm, scratch, mask);
+
+    Register index = scratch;
+    Register probe = mask;
+    __ movq(probe,
+            FieldOperand(number_string_cache,
+                         index,
+                         times_1,
+                         FixedArray::kHeaderSize));
+    __ JumpIfSmi(probe, not_found);
+    ASSERT(CpuFeatures::IsSupported(SSE2));
+    CpuFeatures::Scope fscope(SSE2);
+    __ movsd(xmm0, FieldOperand(object, HeapNumber::kValueOffset));
+    __ movsd(xmm1, FieldOperand(probe, HeapNumber::kValueOffset));
+    __ ucomisd(xmm0, xmm1);
+    __ j(parity_even, not_found);  // Bail out if NaN is involved.
+    __ j(not_equal, not_found);  // The cache did not contain this value.
+    __ jmp(&load_result_from_cache);
+  }
+
+  __ bind(&is_smi);
+  __ SmiToInteger32(scratch, object);
+  GenerateConvertHashCodeToIndex(masm, scratch, mask);
+
+  Register index = scratch;
+  // Check if the entry is the smi we are looking for.
+  __ cmpq(object,
+          FieldOperand(number_string_cache,
+                       index,
+                       times_1,
+                       FixedArray::kHeaderSize));
+  __ j(not_equal, not_found);
+
+  // Get the result from the cache.
+  __ bind(&load_result_from_cache);
+  __ movq(result,
+          FieldOperand(number_string_cache,
+                       index,
+                       times_1,
+                       FixedArray::kHeaderSize + kPointerSize));
+  __ IncrementCounter(&Counters::number_to_string_native, 1);
+}
+
+
+void NumberToStringStub::GenerateConvertHashCodeToIndex(MacroAssembler* masm,
+                                                        Register hash,
+                                                        Register mask) {
+  __ and_(hash, mask);
+  // Each entry in string cache consists of two pointer sized fields,
+  // but times_twice_pointer_size (multiplication by 16) scale factor
+  // is not supported by addrmode on x64 platform.
+  // So we have to premultiply entry index before lookup.
+  __ shl(hash, Immediate(kPointerSizeLog2 + 1));
+}
+
+
+void NumberToStringStub::Generate(MacroAssembler* masm) {
+  Label runtime;
+
+  __ movq(rbx, Operand(rsp, kPointerSize));
+
+  // Generate code to lookup number in the number string cache.
+  GenerateLookupNumberStringCache(masm, rbx, rax, r8, r9, false, &runtime);
+  __ ret(1 * kPointerSize);
+
+  __ bind(&runtime);
+  // Handle number to string in the runtime system if not found in the cache.
+  __ TailCallRuntime(Runtime::kNumberToStringSkipCache, 1, 1);
+}
+
+
+static int NegativeComparisonResult(Condition cc) {
+  ASSERT(cc != equal);
+  ASSERT((cc == less) || (cc == less_equal)
+      || (cc == greater) || (cc == greater_equal));
+  return (cc == greater || cc == greater_equal) ? LESS : GREATER;
+}
+
+
+void CompareStub::Generate(MacroAssembler* masm) {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
+  Label check_unequal_objects, done;
+  // The compare stub returns a positive, negative, or zero 64-bit integer
+  // value in rax, corresponding to result of comparing the two inputs.
+  // NOTICE! This code is only reached after a smi-fast-case check, so
+  // it is certain that at least one operand isn't a smi.
+
+  // Two identical objects are equal unless they are both NaN or undefined.
+  {
+    Label not_identical;
+    __ cmpq(rax, rdx);
+    __ j(not_equal, &not_identical);
+
+    if (cc_ != equal) {
+      // Check for undefined.  undefined OP undefined is false even though
+      // undefined == undefined.
+      Label check_for_nan;
+      __ CompareRoot(rdx, Heap::kUndefinedValueRootIndex);
+      __ j(not_equal, &check_for_nan);
+      __ Set(rax, NegativeComparisonResult(cc_));
+      __ ret(0);
+      __ bind(&check_for_nan);
+    }
+
+    // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
+    // so we do the second best thing - test it ourselves.
+    // Note: if cc_ != equal, never_nan_nan_ is not used.
+    // We cannot set rax to EQUAL until just before return because
+    // rax must be unchanged on jump to not_identical.
+
+    if (never_nan_nan_ && (cc_ == equal)) {
+      __ Set(rax, EQUAL);
+      __ ret(0);
+    } else {
+      Label heap_number;
+      // If it's not a heap number, then return equal for (in)equality operator.
+      __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
+             Factory::heap_number_map());
+      __ j(equal, &heap_number);
+      if (cc_ != equal) {
+        // Call runtime on identical JSObjects.  Otherwise return equal.
+        __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rcx);
+        __ j(above_equal, &not_identical);
+      }
+      __ Set(rax, EQUAL);
+      __ ret(0);
+
+      __ bind(&heap_number);
+      // It is a heap number, so return  equal if it's not NaN.
+      // For NaN, return 1 for every condition except greater and
+      // greater-equal.  Return -1 for them, so the comparison yields
+      // false for all conditions except not-equal.
+      __ Set(rax, EQUAL);
+      __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
+      __ ucomisd(xmm0, xmm0);
+      __ setcc(parity_even, rax);
+      // rax is 0 for equal non-NaN heapnumbers, 1 for NaNs.
+      if (cc_ == greater_equal || cc_ == greater) {
+        __ neg(rax);
+      }
+      __ ret(0);
+    }
+
+    __ bind(&not_identical);
+  }
+
+  if (cc_ == equal) {  // Both strict and non-strict.
+    Label slow;  // Fallthrough label.
+
+    // If we're doing a strict equality comparison, we don't have to do
+    // type conversion, so we generate code to do fast comparison for objects
+    // and oddballs. Non-smi numbers and strings still go through the usual
+    // slow-case code.
+    if (strict_) {
+      // If either is a Smi (we know that not both are), then they can only
+      // be equal if the other is a HeapNumber. If so, use the slow case.
+      {
+        Label not_smis;
+        __ SelectNonSmi(rbx, rax, rdx, &not_smis);
+
+        // Check if the non-smi operand is a heap number.
+        __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
+               Factory::heap_number_map());
+        // If heap number, handle it in the slow case.
+        __ j(equal, &slow);
+        // Return non-equal.  ebx (the lower half of rbx) is not zero.
+        __ movq(rax, rbx);
+        __ ret(0);
+
+        __ bind(&not_smis);
+      }
+
+      // If either operand is a JSObject or an oddball value, then they are not
+      // equal since their pointers are different
+      // There is no test for undetectability in strict equality.
+
+      // If the first object is a JS object, we have done pointer comparison.
+      STATIC_ASSERT(LAST_TYPE == JS_FUNCTION_TYPE);
+      Label first_non_object;
+      __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rcx);
+      __ j(below, &first_non_object);
+      // Return non-zero (eax (not rax) is not zero)
+      Label return_not_equal;
+      STATIC_ASSERT(kHeapObjectTag != 0);
+      __ bind(&return_not_equal);
+      __ ret(0);
+
+      __ bind(&first_non_object);
+      // Check for oddballs: true, false, null, undefined.
+      __ CmpInstanceType(rcx, ODDBALL_TYPE);
+      __ j(equal, &return_not_equal);
+
+      __ CmpObjectType(rdx, FIRST_JS_OBJECT_TYPE, rcx);
+      __ j(above_equal, &return_not_equal);
+
+      // Check for oddballs: true, false, null, undefined.
+      __ CmpInstanceType(rcx, ODDBALL_TYPE);
+      __ j(equal, &return_not_equal);
+
+      // Fall through to the general case.
+    }
+    __ bind(&slow);
+  }
+
+  // Generate the number comparison code.
+  if (include_number_compare_) {
+    Label non_number_comparison;
+    Label unordered;
+    FloatingPointHelper::LoadSSE2UnknownOperands(masm, &non_number_comparison);
+    __ xorl(rax, rax);
+    __ xorl(rcx, rcx);
+    __ ucomisd(xmm0, xmm1);
+
+    // Don't base result on EFLAGS when a NaN is involved.
+    __ j(parity_even, &unordered);
+    // Return a result of -1, 0, or 1, based on EFLAGS.
+    __ setcc(above, rax);
+    __ setcc(below, rcx);
+    __ subq(rax, rcx);
+    __ ret(0);
+
+    // If one of the numbers was NaN, then the result is always false.
+    // The cc is never not-equal.
+    __ bind(&unordered);
+    ASSERT(cc_ != not_equal);
+    if (cc_ == less || cc_ == less_equal) {
+      __ Set(rax, 1);
+    } else {
+      __ Set(rax, -1);
+    }
+    __ ret(0);
+
+    // The number comparison code did not provide a valid result.
+    __ bind(&non_number_comparison);
+  }
+
+  // Fast negative check for symbol-to-symbol equality.
+  Label check_for_strings;
+  if (cc_ == equal) {
+    BranchIfNonSymbol(masm, &check_for_strings, rax, kScratchRegister);
+    BranchIfNonSymbol(masm, &check_for_strings, rdx, kScratchRegister);
+
+    // We've already checked for object identity, so if both operands
+    // are symbols they aren't equal. Register eax (not rax) already holds a
+    // non-zero value, which indicates not equal, so just return.
+    __ ret(0);
+  }
+
+  __ bind(&check_for_strings);
+
+  __ JumpIfNotBothSequentialAsciiStrings(
+      rdx, rax, rcx, rbx, &check_unequal_objects);
+
+  // Inline comparison of ascii strings.
+  StringCompareStub::GenerateCompareFlatAsciiStrings(masm,
+                                                     rdx,
+                                                     rax,
+                                                     rcx,
+                                                     rbx,
+                                                     rdi,
+                                                     r8);
+
+#ifdef DEBUG
+  __ Abort("Unexpected fall-through from string comparison");
+#endif
+
+  __ bind(&check_unequal_objects);
+  if (cc_ == equal && !strict_) {
+    // Not strict equality.  Objects are unequal if
+    // they are both JSObjects and not undetectable,
+    // and their pointers are different.
+    Label not_both_objects, return_unequal;
+    // At most one is a smi, so we can test for smi by adding the two.
+    // A smi plus a heap object has the low bit set, a heap object plus
+    // a heap object has the low bit clear.
+    STATIC_ASSERT(kSmiTag == 0);
+    STATIC_ASSERT(kSmiTagMask == 1);
+    __ lea(rcx, Operand(rax, rdx, times_1, 0));
+    __ testb(rcx, Immediate(kSmiTagMask));
+    __ j(not_zero, &not_both_objects);
+    __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rbx);
+    __ j(below, &not_both_objects);
+    __ CmpObjectType(rdx, FIRST_JS_OBJECT_TYPE, rcx);
+    __ j(below, &not_both_objects);
+    __ testb(FieldOperand(rbx, Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    __ j(zero, &return_unequal);
+    __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    __ j(zero, &return_unequal);
+    // The objects are both undetectable, so they both compare as the value
+    // undefined, and are equal.
+    __ Set(rax, EQUAL);
+    __ bind(&return_unequal);
+    // Return non-equal by returning the non-zero object pointer in eax,
+    // or return equal if we fell through to here.
+    __ ret(0);
+    __ bind(&not_both_objects);
+  }
+
+  // Push arguments below the return address to prepare jump to builtin.
+  __ pop(rcx);
+  __ push(rdx);
+  __ push(rax);
+
+  // Figure out which native to call and setup the arguments.
+  Builtins::JavaScript builtin;
+  if (cc_ == equal) {
+    builtin = strict_ ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
+  } else {
+    builtin = Builtins::COMPARE;
+    __ Push(Smi::FromInt(NegativeComparisonResult(cc_)));
+  }
+
+  // Restore return address on the stack.
+  __ push(rcx);
+
+  // Call the native; it returns -1 (less), 0 (equal), or 1 (greater)
+  // tagged as a small integer.
+  __ InvokeBuiltin(builtin, JUMP_FUNCTION);
+}
+
+
+void CompareStub::BranchIfNonSymbol(MacroAssembler* masm,
+                                    Label* label,
+                                    Register object,
+                                    Register scratch) {
+  __ JumpIfSmi(object, label);
+  __ movq(scratch, FieldOperand(object, HeapObject::kMapOffset));
+  __ movzxbq(scratch,
+             FieldOperand(scratch, Map::kInstanceTypeOffset));
+  // Ensure that no non-strings have the symbol bit set.
+  STATIC_ASSERT(LAST_TYPE < kNotStringTag + kIsSymbolMask);
+  STATIC_ASSERT(kSymbolTag != 0);
+  __ testb(scratch, Immediate(kIsSymbolMask));
+  __ j(zero, label);
+}
+
+
+void StackCheckStub::Generate(MacroAssembler* masm) {
+  // Because builtins always remove the receiver from the stack, we
+  // have to fake one to avoid underflowing the stack. The receiver
+  // must be inserted below the return address on the stack so we
+  // temporarily store that in a register.
+  __ pop(rax);
+  __ Push(Smi::FromInt(0));
+  __ push(rax);
+
+  // Do tail-call to runtime routine.
+  __ TailCallRuntime(Runtime::kStackGuard, 1, 1);
+}
+
+
+void CallFunctionStub::Generate(MacroAssembler* masm) {
+  Label slow;
+
+  // If the receiver might be a value (string, number or boolean) check for this
+  // and box it if it is.
+  if (ReceiverMightBeValue()) {
+    // Get the receiver from the stack.
+    // +1 ~ return address
+    Label receiver_is_value, receiver_is_js_object;
+    __ movq(rax, Operand(rsp, (argc_ + 1) * kPointerSize));
+
+    // Check if receiver is a smi (which is a number value).
+    __ JumpIfSmi(rax, &receiver_is_value);
+
+    // Check if the receiver is a valid JS object.
+    __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rdi);
+    __ j(above_equal, &receiver_is_js_object);
+
+    // Call the runtime to box the value.
+    __ bind(&receiver_is_value);
+    __ EnterInternalFrame();
+    __ push(rax);
+    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+    __ LeaveInternalFrame();
+    __ movq(Operand(rsp, (argc_ + 1) * kPointerSize), rax);
+
+    __ bind(&receiver_is_js_object);
+  }
+
+  // Get the function to call from the stack.
+  // +2 ~ receiver, return address
+  __ movq(rdi, Operand(rsp, (argc_ + 2) * kPointerSize));
+
+  // Check that the function really is a JavaScript function.
+  __ JumpIfSmi(rdi, &slow);
+  // Goto slow case if we do not have a function.
+  __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
+  __ j(not_equal, &slow);
+
+  // Fast-case: Just invoke the function.
+  ParameterCount actual(argc_);
+  __ InvokeFunction(rdi, actual, JUMP_FUNCTION);
+
+  // Slow-case: Non-function called.
+  __ bind(&slow);
+  // CALL_NON_FUNCTION expects the non-function callee as receiver (instead
+  // of the original receiver from the call site).
+  __ movq(Operand(rsp, (argc_ + 1) * kPointerSize), rdi);
+  __ Set(rax, argc_);
+  __ Set(rbx, 0);
+  __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION);
+  Handle<Code> adaptor(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
+  __ Jump(adaptor, RelocInfo::CODE_TARGET);
+}
+
+
+void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
+  // Check that stack should contain next handler, frame pointer, state and
+  // return address in that order.
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset + kPointerSize ==
+            StackHandlerConstants::kStateOffset);
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset + kPointerSize ==
+            StackHandlerConstants::kPCOffset);
+
+  ExternalReference handler_address(Top::k_handler_address);
+  __ movq(kScratchRegister, handler_address);
+  __ movq(rsp, Operand(kScratchRegister, 0));
+  // get next in chain
+  __ pop(rcx);
+  __ movq(Operand(kScratchRegister, 0), rcx);
+  __ pop(rbp);  // pop frame pointer
+  __ pop(rdx);  // remove state
+
+  // Before returning we restore the context from the frame pointer if not NULL.
+  // The frame pointer is NULL in the exception handler of a JS entry frame.
+  __ xor_(rsi, rsi);  // tentatively set context pointer to NULL
+  Label skip;
+  __ cmpq(rbp, Immediate(0));
+  __ j(equal, &skip);
+  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
+  __ bind(&skip);
+  __ ret(0);
+}
+
+
+void ApiGetterEntryStub::Generate(MacroAssembler* masm) {
+  Label empty_result;
+  Label prologue;
+  Label promote_scheduled_exception;
+  __ EnterApiExitFrame(kStackSpace, 0);
+  ASSERT_EQ(kArgc, 4);
+#ifdef _WIN64
+  // All the parameters should be set up by a caller.
+#else
+  // Set 1st parameter register with property name.
+  __ movq(rsi, rdx);
+  // Second parameter register rdi should be set with pointer to AccessorInfo
+  // by a caller.
+#endif
+  // Call the api function!
+  __ movq(rax,
+          reinterpret_cast<int64_t>(fun()->address()),
+          RelocInfo::RUNTIME_ENTRY);
+  __ call(rax);
+  // Check if the function scheduled an exception.
+  ExternalReference scheduled_exception_address =
+      ExternalReference::scheduled_exception_address();
+  __ movq(rsi, scheduled_exception_address);
+  __ Cmp(Operand(rsi, 0), Factory::the_hole_value());
+  __ j(not_equal, &promote_scheduled_exception);
+#ifdef _WIN64
+  // rax keeps a pointer to v8::Handle, unpack it.
+  __ movq(rax, Operand(rax, 0));
+#endif
+  // Check if the result handle holds 0.
+  __ testq(rax, rax);
+  __ j(zero, &empty_result);
+  // It was non-zero.  Dereference to get the result value.
+  __ movq(rax, Operand(rax, 0));
+  __ bind(&prologue);
+  __ LeaveExitFrame();
+  __ ret(0);
+  __ bind(&promote_scheduled_exception);
+  __ TailCallRuntime(Runtime::kPromoteScheduledException, 0, 1);
+  __ bind(&empty_result);
+  // It was zero; the result is undefined.
+  __ Move(rax, Factory::undefined_value());
+  __ jmp(&prologue);
+}
+
+
+void CEntryStub::GenerateCore(MacroAssembler* masm,
+                              Label* throw_normal_exception,
+                              Label* throw_termination_exception,
+                              Label* throw_out_of_memory_exception,
+                              bool do_gc,
+                              bool always_allocate_scope,
+                              int /* alignment_skew */) {
+  // rax: result parameter for PerformGC, if any.
+  // rbx: pointer to C function  (C callee-saved).
+  // rbp: frame pointer  (restored after C call).
+  // rsp: stack pointer  (restored after C call).
+  // r14: number of arguments including receiver (C callee-saved).
+  // r12: pointer to the first argument (C callee-saved).
+  //      This pointer is reused in LeaveExitFrame(), so it is stored in a
+  //      callee-saved register.
+
+  // Simple results returned in rax (both AMD64 and Win64 calling conventions).
+  // Complex results must be written to address passed as first argument.
+  // AMD64 calling convention: a struct of two pointers in rax+rdx
+
+  // Check stack alignment.
+  if (FLAG_debug_code) {
+    __ CheckStackAlignment();
+  }
+
+  if (do_gc) {
+    // Pass failure code returned from last attempt as first argument to
+    // PerformGC. No need to use PrepareCallCFunction/CallCFunction here as the
+    // stack is known to be aligned. This function takes one argument which is
+    // passed in register.
+#ifdef _WIN64
+    __ movq(rcx, rax);
+#else  // _WIN64
+    __ movq(rdi, rax);
+#endif
+    __ movq(kScratchRegister,
+            FUNCTION_ADDR(Runtime::PerformGC),
+            RelocInfo::RUNTIME_ENTRY);
+    __ call(kScratchRegister);
+  }
+
+  ExternalReference scope_depth =
+      ExternalReference::heap_always_allocate_scope_depth();
+  if (always_allocate_scope) {
+    __ movq(kScratchRegister, scope_depth);
+    __ incl(Operand(kScratchRegister, 0));
+  }
+
+  // Call C function.
+#ifdef _WIN64
+  // Windows 64-bit ABI passes arguments in rcx, rdx, r8, r9
+  // Store Arguments object on stack, below the 4 WIN64 ABI parameter slots.
+  __ movq(Operand(rsp, 4 * kPointerSize), r14);  // argc.
+  __ movq(Operand(rsp, 5 * kPointerSize), r12);  // argv.
+  if (result_size_ < 2) {
+    // Pass a pointer to the Arguments object as the first argument.
+    // Return result in single register (rax).
+    __ lea(rcx, Operand(rsp, 4 * kPointerSize));
+  } else {
+    ASSERT_EQ(2, result_size_);
+    // Pass a pointer to the result location as the first argument.
+    __ lea(rcx, Operand(rsp, 6 * kPointerSize));
+    // Pass a pointer to the Arguments object as the second argument.
+    __ lea(rdx, Operand(rsp, 4 * kPointerSize));
+  }
+
+#else  // _WIN64
+  // GCC passes arguments in rdi, rsi, rdx, rcx, r8, r9.
+  __ movq(rdi, r14);  // argc.
+  __ movq(rsi, r12);  // argv.
+#endif
+  __ call(rbx);
+  // Result is in rax - do not destroy this register!
+
+  if (always_allocate_scope) {
+    __ movq(kScratchRegister, scope_depth);
+    __ decl(Operand(kScratchRegister, 0));
+  }
+
+  // Check for failure result.
+  Label failure_returned;
+  STATIC_ASSERT(((kFailureTag + 1) & kFailureTagMask) == 0);
+#ifdef _WIN64
+  // If return value is on the stack, pop it to registers.
+  if (result_size_ > 1) {
+    ASSERT_EQ(2, result_size_);
+    // Read result values stored on stack. Result is stored
+    // above the four argument mirror slots and the two
+    // Arguments object slots.
+    __ movq(rax, Operand(rsp, 6 * kPointerSize));
+    __ movq(rdx, Operand(rsp, 7 * kPointerSize));
+  }
+#endif
+  __ lea(rcx, Operand(rax, 1));
+  // Lower 2 bits of rcx are 0 iff rax has failure tag.
+  __ testl(rcx, Immediate(kFailureTagMask));
+  __ j(zero, &failure_returned);
+
+  // Exit the JavaScript to C++ exit frame.
+  __ LeaveExitFrame(result_size_);
+  __ ret(0);
+
+  // Handling of failure.
+  __ bind(&failure_returned);
+
+  Label retry;
+  // If the returned exception is RETRY_AFTER_GC continue at retry label
+  STATIC_ASSERT(Failure::RETRY_AFTER_GC == 0);
+  __ testl(rax, Immediate(((1 << kFailureTypeTagSize) - 1) << kFailureTagSize));
+  __ j(zero, &retry);
+
+  // Special handling of out of memory exceptions.
+  __ movq(kScratchRegister, Failure::OutOfMemoryException(), RelocInfo::NONE);
+  __ cmpq(rax, kScratchRegister);
+  __ j(equal, throw_out_of_memory_exception);
+
+  // Retrieve the pending exception and clear the variable.
+  ExternalReference pending_exception_address(Top::k_pending_exception_address);
+  __ movq(kScratchRegister, pending_exception_address);
+  __ movq(rax, Operand(kScratchRegister, 0));
+  __ movq(rdx, ExternalReference::the_hole_value_location());
+  __ movq(rdx, Operand(rdx, 0));
+  __ movq(Operand(kScratchRegister, 0), rdx);
+
+  // Special handling of termination exceptions which are uncatchable
+  // by javascript code.
+  __ CompareRoot(rax, Heap::kTerminationExceptionRootIndex);
+  __ j(equal, throw_termination_exception);
+
+  // Handle normal exception.
+  __ jmp(throw_normal_exception);
+
+  // Retry.
+  __ bind(&retry);
+}
+
+
+void CEntryStub::GenerateThrowUncatchable(MacroAssembler* masm,
+                                          UncatchableExceptionType type) {
+  // Fetch top stack handler.
+  ExternalReference handler_address(Top::k_handler_address);
+  __ movq(kScratchRegister, handler_address);
+  __ movq(rsp, Operand(kScratchRegister, 0));
+
+  // Unwind the handlers until the ENTRY handler is found.
+  Label loop, done;
+  __ bind(&loop);
+  // Load the type of the current stack handler.
+  const int kStateOffset = StackHandlerConstants::kStateOffset;
+  __ cmpq(Operand(rsp, kStateOffset), Immediate(StackHandler::ENTRY));
+  __ j(equal, &done);
+  // Fetch the next handler in the list.
+  const int kNextOffset = StackHandlerConstants::kNextOffset;
+  __ movq(rsp, Operand(rsp, kNextOffset));
+  __ jmp(&loop);
+  __ bind(&done);
+
+  // Set the top handler address to next handler past the current ENTRY handler.
+  __ movq(kScratchRegister, handler_address);
+  __ pop(Operand(kScratchRegister, 0));
+
+  if (type == OUT_OF_MEMORY) {
+    // Set external caught exception to false.
+    ExternalReference external_caught(Top::k_external_caught_exception_address);
+    __ movq(rax, Immediate(false));
+    __ store_rax(external_caught);
+
+    // Set pending exception and rax to out of memory exception.
+    ExternalReference pending_exception(Top::k_pending_exception_address);
+    __ movq(rax, Failure::OutOfMemoryException(), RelocInfo::NONE);
+    __ store_rax(pending_exception);
+  }
+
+  // Clear the context pointer.
+  __ xor_(rsi, rsi);
+
+  // Restore registers from handler.
+  STATIC_ASSERT(StackHandlerConstants::kNextOffset + kPointerSize ==
+            StackHandlerConstants::kFPOffset);
+  __ pop(rbp);  // FP
+  STATIC_ASSERT(StackHandlerConstants::kFPOffset + kPointerSize ==
+            StackHandlerConstants::kStateOffset);
+  __ pop(rdx);  // State
+
+  STATIC_ASSERT(StackHandlerConstants::kStateOffset + kPointerSize ==
+            StackHandlerConstants::kPCOffset);
+  __ ret(0);
+}
+
+
+void CEntryStub::Generate(MacroAssembler* masm) {
+  // rax: number of arguments including receiver
+  // rbx: pointer to C function  (C callee-saved)
+  // rbp: frame pointer of calling JS frame (restored after C call)
+  // rsp: stack pointer  (restored after C call)
+  // rsi: current context (restored)
+
+  // NOTE: Invocations of builtins may return failure objects
+  // instead of a proper result. The builtin entry handles
+  // this by performing a garbage collection and retrying the
+  // builtin once.
+
+  // Enter the exit frame that transitions from JavaScript to C++.
+  __ EnterExitFrame(result_size_);
+
+  // rax: Holds the context at this point, but should not be used.
+  //      On entry to code generated by GenerateCore, it must hold
+  //      a failure result if the collect_garbage argument to GenerateCore
+  //      is true.  This failure result can be the result of code
+  //      generated by a previous call to GenerateCore.  The value
+  //      of rax is then passed to Runtime::PerformGC.
+  // rbx: pointer to builtin function  (C callee-saved).
+  // rbp: frame pointer of exit frame  (restored after C call).
+  // rsp: stack pointer (restored after C call).
+  // r14: number of arguments including receiver (C callee-saved).
+  // r12: argv pointer (C callee-saved).
+
+  Label throw_normal_exception;
+  Label throw_termination_exception;
+  Label throw_out_of_memory_exception;
+
+  // Call into the runtime system.
+  GenerateCore(masm,
+               &throw_normal_exception,
+               &throw_termination_exception,
+               &throw_out_of_memory_exception,
+               false,
+               false);
+
+  // Do space-specific GC and retry runtime call.
+  GenerateCore(masm,
+               &throw_normal_exception,
+               &throw_termination_exception,
+               &throw_out_of_memory_exception,
+               true,
+               false);
+
+  // Do full GC and retry runtime call one final time.
+  Failure* failure = Failure::InternalError();
+  __ movq(rax, failure, RelocInfo::NONE);
+  GenerateCore(masm,
+               &throw_normal_exception,
+               &throw_termination_exception,
+               &throw_out_of_memory_exception,
+               true,
+               true);
+
+  __ bind(&throw_out_of_memory_exception);
+  GenerateThrowUncatchable(masm, OUT_OF_MEMORY);
+
+  __ bind(&throw_termination_exception);
+  GenerateThrowUncatchable(masm, TERMINATION);
+
+  __ bind(&throw_normal_exception);
+  GenerateThrowTOS(masm);
+}
+
+
+void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
+  Label invoke, exit;
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  Label not_outermost_js, not_outermost_js_2;
+#endif
+
+  // Setup frame.
+  __ push(rbp);
+  __ movq(rbp, rsp);
+
+  // Push the stack frame type marker twice.
+  int marker = is_construct ? StackFrame::ENTRY_CONSTRUCT : StackFrame::ENTRY;
+  // Scratch register is neither callee-save, nor an argument register on any
+  // platform. It's free to use at this point.
+  // Cannot use smi-register for loading yet.
+  __ movq(kScratchRegister,
+          reinterpret_cast<uint64_t>(Smi::FromInt(marker)),
+          RelocInfo::NONE);
+  __ push(kScratchRegister);  // context slot
+  __ push(kScratchRegister);  // function slot
+  // Save callee-saved registers (X64/Win64 calling conventions).
+  __ push(r12);
+  __ push(r13);
+  __ push(r14);
+  __ push(r15);
+#ifdef _WIN64
+  __ push(rdi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
+  __ push(rsi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
+#endif
+  __ push(rbx);
+  // TODO(X64): On Win64, if we ever use XMM6-XMM15, the low low 64 bits are
+  // callee save as well.
+
+  // Save copies of the top frame descriptor on the stack.
+  ExternalReference c_entry_fp(Top::k_c_entry_fp_address);
+  __ load_rax(c_entry_fp);
+  __ push(rax);
+
+  // Set up the roots and smi constant registers.
+  // Needs to be done before any further smi loads.
+  ExternalReference roots_address = ExternalReference::roots_address();
+  __ movq(kRootRegister, roots_address);
+  __ InitializeSmiConstantRegister();
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // If this is the outermost JS call, set js_entry_sp value.
+  ExternalReference js_entry_sp(Top::k_js_entry_sp_address);
+  __ load_rax(js_entry_sp);
+  __ testq(rax, rax);
+  __ j(not_zero, &not_outermost_js);
+  __ movq(rax, rbp);
+  __ store_rax(js_entry_sp);
+  __ bind(&not_outermost_js);
+#endif
+
+  // Call a faked try-block that does the invoke.
+  __ call(&invoke);
+
+  // Caught exception: Store result (exception) in the pending
+  // exception field in the JSEnv and return a failure sentinel.
+  ExternalReference pending_exception(Top::k_pending_exception_address);
+  __ store_rax(pending_exception);
+  __ movq(rax, Failure::Exception(), RelocInfo::NONE);
+  __ jmp(&exit);
+
+  // Invoke: Link this frame into the handler chain.
+  __ bind(&invoke);
+  __ PushTryHandler(IN_JS_ENTRY, JS_ENTRY_HANDLER);
+
+  // Clear any pending exceptions.
+  __ load_rax(ExternalReference::the_hole_value_location());
+  __ store_rax(pending_exception);
+
+  // Fake a receiver (NULL).
+  __ push(Immediate(0));  // receiver
+
+  // Invoke the function by calling through JS entry trampoline
+  // builtin and pop the faked function when we return. We load the address
+  // from an external reference instead of inlining the call target address
+  // directly in the code, because the builtin stubs may not have been
+  // generated yet at the time this code is generated.
+  if (is_construct) {
+    ExternalReference construct_entry(Builtins::JSConstructEntryTrampoline);
+    __ load_rax(construct_entry);
+  } else {
+    ExternalReference entry(Builtins::JSEntryTrampoline);
+    __ load_rax(entry);
+  }
+  __ lea(kScratchRegister, FieldOperand(rax, Code::kHeaderSize));
+  __ call(kScratchRegister);
+
+  // Unlink this frame from the handler chain.
+  __ movq(kScratchRegister, ExternalReference(Top::k_handler_address));
+  __ pop(Operand(kScratchRegister, 0));
+  // Pop next_sp.
+  __ addq(rsp, Immediate(StackHandlerConstants::kSize - kPointerSize));
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // If current EBP value is the same as js_entry_sp value, it means that
+  // the current function is the outermost.
+  __ movq(kScratchRegister, js_entry_sp);
+  __ cmpq(rbp, Operand(kScratchRegister, 0));
+  __ j(not_equal, &not_outermost_js_2);
+  __ movq(Operand(kScratchRegister, 0), Immediate(0));
+  __ bind(&not_outermost_js_2);
+#endif
+
+  // Restore the top frame descriptor from the stack.
+  __ bind(&exit);
+  __ movq(kScratchRegister, ExternalReference(Top::k_c_entry_fp_address));
+  __ pop(Operand(kScratchRegister, 0));
+
+  // Restore callee-saved registers (X64 conventions).
+  __ pop(rbx);
+#ifdef _WIN64
+  // Callee save on in Win64 ABI, arguments/volatile in AMD64 ABI.
+  __ pop(rsi);
+  __ pop(rdi);
+#endif
+  __ pop(r15);
+  __ pop(r14);
+  __ pop(r13);
+  __ pop(r12);
+  __ addq(rsp, Immediate(2 * kPointerSize));  // remove markers
+
+  // Restore frame pointer and return.
+  __ pop(rbp);
+  __ ret(0);
+}
+
+
+void InstanceofStub::Generate(MacroAssembler* masm) {
+  // Implements "value instanceof function" operator.
+  // Expected input state:
+  //   rsp[0] : return address
+  //   rsp[1] : function pointer
+  //   rsp[2] : value
+  // Returns a bitwise zero to indicate that the value
+  // is and instance of the function and anything else to
+  // indicate that the value is not an instance.
+
+  // Get the object - go slow case if it's a smi.
+  Label slow;
+  __ movq(rax, Operand(rsp, 2 * kPointerSize));
+  __ JumpIfSmi(rax, &slow);
+
+  // Check that the left hand is a JS object. Leave its map in rax.
+  __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rax);
+  __ j(below, &slow);
+  __ CmpInstanceType(rax, LAST_JS_OBJECT_TYPE);
+  __ j(above, &slow);
+
+  // Get the prototype of the function.
+  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
+  // rdx is function, rax is map.
+
+  // Look up the function and the map in the instanceof cache.
+  Label miss;
+  __ CompareRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
+  __ j(not_equal, &miss);
+  __ CompareRoot(rax, Heap::kInstanceofCacheMapRootIndex);
+  __ j(not_equal, &miss);
+  __ LoadRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
+  __ ret(2 * kPointerSize);
+
+  __ bind(&miss);
+  __ TryGetFunctionPrototype(rdx, rbx, &slow);
+
+  // Check that the function prototype is a JS object.
+  __ JumpIfSmi(rbx, &slow);
+  __ CmpObjectType(rbx, FIRST_JS_OBJECT_TYPE, kScratchRegister);
+  __ j(below, &slow);
+  __ CmpInstanceType(kScratchRegister, LAST_JS_OBJECT_TYPE);
+  __ j(above, &slow);
+
+  // Register mapping:
+  //   rax is object map.
+  //   rdx is function.
+  //   rbx is function prototype.
+  __ StoreRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
+  __ StoreRoot(rax, Heap::kInstanceofCacheMapRootIndex);
+
+  __ movq(rcx, FieldOperand(rax, Map::kPrototypeOffset));
+
+  // Loop through the prototype chain looking for the function prototype.
+  Label loop, is_instance, is_not_instance;
+  __ LoadRoot(kScratchRegister, Heap::kNullValueRootIndex);
+  __ bind(&loop);
+  __ cmpq(rcx, rbx);
+  __ j(equal, &is_instance);
+  __ cmpq(rcx, kScratchRegister);
+  // The code at is_not_instance assumes that kScratchRegister contains a
+  // non-zero GCable value (the null object in this case).
+  __ j(equal, &is_not_instance);
+  __ movq(rcx, FieldOperand(rcx, HeapObject::kMapOffset));
+  __ movq(rcx, FieldOperand(rcx, Map::kPrototypeOffset));
+  __ jmp(&loop);
+
+  __ bind(&is_instance);
+  __ xorl(rax, rax);
+  // Store bitwise zero in the cache.  This is a Smi in GC terms.
+  STATIC_ASSERT(kSmiTag == 0);
+  __ StoreRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
+  __ ret(2 * kPointerSize);
+
+  __ bind(&is_not_instance);
+  // We have to store a non-zero value in the cache.
+  __ StoreRoot(kScratchRegister, Heap::kInstanceofCacheAnswerRootIndex);
+  __ ret(2 * kPointerSize);
+
+  // Slow-case: Go through the JavaScript implementation.
+  __ bind(&slow);
+  __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
+}
+
+
+int CompareStub::MinorKey() {
+  // Encode the three parameters in a unique 16 bit value. To avoid duplicate
+  // stubs the never NaN NaN condition is only taken into account if the
+  // condition is equals.
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 12));
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+  return ConditionField::encode(static_cast<unsigned>(cc_))
+         | RegisterField::encode(false)    // lhs_ and rhs_ are not used
+         | StrictField::encode(strict_)
+         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
+         | IncludeNumberCompareField::encode(include_number_compare_);
+}
+
+
+// Unfortunately you have to run without snapshots to see most of these
+// names in the profile since most compare stubs end up in the snapshot.
+const char* CompareStub::GetName() {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
+  if (name_ != NULL) return name_;
+  const int kMaxNameLength = 100;
+  name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);
+  if (name_ == NULL) return "OOM";
+
+  const char* cc_name;
+  switch (cc_) {
+    case less: cc_name = "LT"; break;
+    case greater: cc_name = "GT"; break;
+    case less_equal: cc_name = "LE"; break;
+    case greater_equal: cc_name = "GE"; break;
+    case equal: cc_name = "EQ"; break;
+    case not_equal: cc_name = "NE"; break;
+    default: cc_name = "UnknownCondition"; break;
+  }
+
+  const char* strict_name = "";
+  if (strict_ && (cc_ == equal || cc_ == not_equal)) {
+    strict_name = "_STRICT";
+  }
+
+  const char* never_nan_nan_name = "";
+  if (never_nan_nan_ && (cc_ == equal || cc_ == not_equal)) {
+    never_nan_nan_name = "_NO_NAN";
+  }
+
+  const char* include_number_compare_name = "";
+  if (!include_number_compare_) {
+    include_number_compare_name = "_NO_NUMBER";
+  }
+
+  OS::SNPrintF(Vector<char>(name_, kMaxNameLength),
+               "CompareStub_%s%s%s%s",
+               cc_name,
+               strict_name,
+               never_nan_nan_name,
+               include_number_compare_name);
+  return name_;
+}
+
+
+// -------------------------------------------------------------------------
+// StringCharCodeAtGenerator
+
+void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
+  Label flat_string;
+  Label ascii_string;
+  Label got_char_code;
+
+  // If the receiver is a smi trigger the non-string case.
+  __ JumpIfSmi(object_, receiver_not_string_);
+
+  // Fetch the instance type of the receiver into result register.
+  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
+  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
+  // If the receiver is not a string trigger the non-string case.
+  __ testb(result_, Immediate(kIsNotStringMask));
+  __ j(not_zero, receiver_not_string_);
+
+  // If the index is non-smi trigger the non-smi case.
+  __ JumpIfNotSmi(index_, &index_not_smi_);
+
+  // Put smi-tagged index into scratch register.
+  __ movq(scratch_, index_);
+  __ bind(&got_smi_index_);
+
+  // Check for index out of range.
+  __ SmiCompare(scratch_, FieldOperand(object_, String::kLengthOffset));
+  __ j(above_equal, index_out_of_range_);
+
+  // We need special handling for non-flat strings.
+  STATIC_ASSERT(kSeqStringTag == 0);
+  __ testb(result_, Immediate(kStringRepresentationMask));
+  __ j(zero, &flat_string);
+
+  // Handle non-flat strings.
+  __ testb(result_, Immediate(kIsConsStringMask));
+  __ j(zero, &call_runtime_);
+
+  // ConsString.
+  // Check whether the right hand side is the empty string (i.e. if
+  // this is really a flat string in a cons string). If that is not
+  // the case we would rather go to the runtime system now to flatten
+  // the string.
+  __ CompareRoot(FieldOperand(object_, ConsString::kSecondOffset),
+                 Heap::kEmptyStringRootIndex);
+  __ j(not_equal, &call_runtime_);
+  // Get the first of the two strings and load its instance type.
+  __ movq(object_, FieldOperand(object_, ConsString::kFirstOffset));
+  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
+  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
+  // If the first cons component is also non-flat, then go to runtime.
+  STATIC_ASSERT(kSeqStringTag == 0);
+  __ testb(result_, Immediate(kStringRepresentationMask));
+  __ j(not_zero, &call_runtime_);
+
+  // Check for 1-byte or 2-byte string.
+  __ bind(&flat_string);
+  STATIC_ASSERT(kAsciiStringTag != 0);
+  __ testb(result_, Immediate(kStringEncodingMask));
+  __ j(not_zero, &ascii_string);
+
+  // 2-byte string.
+  // Load the 2-byte character code into the result register.
+  __ SmiToInteger32(scratch_, scratch_);
+  __ movzxwl(result_, FieldOperand(object_,
+                                   scratch_, times_2,
+                                   SeqTwoByteString::kHeaderSize));
+  __ jmp(&got_char_code);
+
+  // ASCII string.
+  // Load the byte into the result register.
+  __ bind(&ascii_string);
+  __ SmiToInteger32(scratch_, scratch_);
+  __ movzxbl(result_, FieldOperand(object_,
+                                   scratch_, times_1,
+                                   SeqAsciiString::kHeaderSize));
+  __ bind(&got_char_code);
+  __ Integer32ToSmi(result_, result_);
+  __ bind(&exit_);
+}
+
+
+void StringCharCodeAtGenerator::GenerateSlow(
+    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
+  __ Abort("Unexpected fallthrough to CharCodeAt slow case");
+
+  // Index is not a smi.
+  __ bind(&index_not_smi_);
+  // If index is a heap number, try converting it to an integer.
+  __ CheckMap(index_, Factory::heap_number_map(), index_not_number_, true);
+  call_helper.BeforeCall(masm);
+  __ push(object_);
+  __ push(index_);
+  __ push(index_);  // Consumed by runtime conversion function.
+  if (index_flags_ == STRING_INDEX_IS_NUMBER) {
+    __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
+  } else {
+    ASSERT(index_flags_ == STRING_INDEX_IS_ARRAY_INDEX);
+    // NumberToSmi discards numbers that are not exact integers.
+    __ CallRuntime(Runtime::kNumberToSmi, 1);
+  }
+  if (!scratch_.is(rax)) {
+    // Save the conversion result before the pop instructions below
+    // have a chance to overwrite it.
+    __ movq(scratch_, rax);
+  }
+  __ pop(index_);
+  __ pop(object_);
+  // Reload the instance type.
+  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
+  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
+  call_helper.AfterCall(masm);
+  // If index is still not a smi, it must be out of range.
+  __ JumpIfNotSmi(scratch_, index_out_of_range_);
+  // Otherwise, return to the fast path.
+  __ jmp(&got_smi_index_);
+
+  // Call runtime. We get here when the receiver is a string and the
+  // index is a number, but the code of getting the actual character
+  // is too complex (e.g., when the string needs to be flattened).
+  __ bind(&call_runtime_);
+  call_helper.BeforeCall(masm);
+  __ push(object_);
+  __ push(index_);
+  __ CallRuntime(Runtime::kStringCharCodeAt, 2);
+  if (!result_.is(rax)) {
+    __ movq(result_, rax);
+  }
+  call_helper.AfterCall(masm);
+  __ jmp(&exit_);
+
+  __ Abort("Unexpected fallthrough from CharCodeAt slow case");
+}
+
+
+// -------------------------------------------------------------------------
+// StringCharFromCodeGenerator
+
+void StringCharFromCodeGenerator::GenerateFast(MacroAssembler* masm) {
+  // Fast case of Heap::LookupSingleCharacterStringFromCode.
+  __ JumpIfNotSmi(code_, &slow_case_);
+  __ SmiCompare(code_, Smi::FromInt(String::kMaxAsciiCharCode));
+  __ j(above, &slow_case_);
+
+  __ LoadRoot(result_, Heap::kSingleCharacterStringCacheRootIndex);
+  SmiIndex index = masm->SmiToIndex(kScratchRegister, code_, kPointerSizeLog2);
+  __ movq(result_, FieldOperand(result_, index.reg, index.scale,
+                                FixedArray::kHeaderSize));
+  __ CompareRoot(result_, Heap::kUndefinedValueRootIndex);
+  __ j(equal, &slow_case_);
+  __ bind(&exit_);
+}
+
+
+void StringCharFromCodeGenerator::GenerateSlow(
+    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
+  __ Abort("Unexpected fallthrough to CharFromCode slow case");
+
+  __ bind(&slow_case_);
+  call_helper.BeforeCall(masm);
+  __ push(code_);
+  __ CallRuntime(Runtime::kCharFromCode, 1);
+  if (!result_.is(rax)) {
+    __ movq(result_, rax);
+  }
+  call_helper.AfterCall(masm);
+  __ jmp(&exit_);
+
+  __ Abort("Unexpected fallthrough from CharFromCode slow case");
+}
+
+
+// -------------------------------------------------------------------------
+// StringCharAtGenerator
+
+void StringCharAtGenerator::GenerateFast(MacroAssembler* masm) {
+  char_code_at_generator_.GenerateFast(masm);
+  char_from_code_generator_.GenerateFast(masm);
+}
+
+
+void StringCharAtGenerator::GenerateSlow(
+    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
+  char_code_at_generator_.GenerateSlow(masm, call_helper);
+  char_from_code_generator_.GenerateSlow(masm, call_helper);
+}
+
+
+void StringAddStub::Generate(MacroAssembler* masm) {
+  Label string_add_runtime;
+
+  // Load the two arguments.
+  __ movq(rax, Operand(rsp, 2 * kPointerSize));  // First argument.
+  __ movq(rdx, Operand(rsp, 1 * kPointerSize));  // Second argument.
+
+  // Make sure that both arguments are strings if not known in advance.
+  if (string_check_) {
+    Condition is_smi;
+    is_smi = masm->CheckSmi(rax);
+    __ j(is_smi, &string_add_runtime);
+    __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, r8);
+    __ j(above_equal, &string_add_runtime);
+
+    // First argument is a a string, test second.
+    is_smi = masm->CheckSmi(rdx);
+    __ j(is_smi, &string_add_runtime);
+    __ CmpObjectType(rdx, FIRST_NONSTRING_TYPE, r9);
+    __ j(above_equal, &string_add_runtime);
+  }
+
+  // Both arguments are strings.
+  // rax: first string
+  // rdx: second string
+  // Check if either of the strings are empty. In that case return the other.
+  Label second_not_zero_length, both_not_zero_length;
+  __ movq(rcx, FieldOperand(rdx, String::kLengthOffset));
+  __ SmiTest(rcx);
+  __ j(not_zero, &second_not_zero_length);
+  // Second string is empty, result is first string which is already in rax.
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+  __ bind(&second_not_zero_length);
+  __ movq(rbx, FieldOperand(rax, String::kLengthOffset));
+  __ SmiTest(rbx);
+  __ j(not_zero, &both_not_zero_length);
+  // First string is empty, result is second string which is in rdx.
+  __ movq(rax, rdx);
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+
+  // Both strings are non-empty.
+  // rax: first string
+  // rbx: length of first string
+  // rcx: length of second string
+  // rdx: second string
+  // r8: map of first string if string check was performed above
+  // r9: map of second string if string check was performed above
+  Label string_add_flat_result, longer_than_two;
+  __ bind(&both_not_zero_length);
+
+  // If arguments where known to be strings, maps are not loaded to r8 and r9
+  // by the code above.
+  if (!string_check_) {
+    __ movq(r8, FieldOperand(rax, HeapObject::kMapOffset));
+    __ movq(r9, FieldOperand(rdx, HeapObject::kMapOffset));
+  }
+  // Get the instance types of the two strings as they will be needed soon.
+  __ movzxbl(r8, FieldOperand(r8, Map::kInstanceTypeOffset));
+  __ movzxbl(r9, FieldOperand(r9, Map::kInstanceTypeOffset));
+
+  // Look at the length of the result of adding the two strings.
+  STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue / 2);
+  __ SmiAdd(rbx, rbx, rcx, NULL);
+  // Use the runtime system when adding two one character strings, as it
+  // contains optimizations for this specific case using the symbol table.
+  __ SmiCompare(rbx, Smi::FromInt(2));
+  __ j(not_equal, &longer_than_two);
+
+  // Check that both strings are non-external ascii strings.
+  __ JumpIfBothInstanceTypesAreNotSequentialAscii(r8, r9, rbx, rcx,
+                                                  &string_add_runtime);
+
+  // Get the two characters forming the sub string.
+  __ movzxbq(rbx, FieldOperand(rax, SeqAsciiString::kHeaderSize));
+  __ movzxbq(rcx, FieldOperand(rdx, SeqAsciiString::kHeaderSize));
+
+  // Try to lookup two character string in symbol table. If it is not found
+  // just allocate a new one.
+  Label make_two_character_string, make_flat_ascii_string;
+  StringHelper::GenerateTwoCharacterSymbolTableProbe(
+      masm, rbx, rcx, r14, r11, rdi, r12, &make_two_character_string);
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+
+  __ bind(&make_two_character_string);
+  __ Set(rbx, 2);
+  __ jmp(&make_flat_ascii_string);
+
+  __ bind(&longer_than_two);
+  // Check if resulting string will be flat.
+  __ SmiCompare(rbx, Smi::FromInt(String::kMinNonFlatLength));
+  __ j(below, &string_add_flat_result);
+  // Handle exceptionally long strings in the runtime system.
+  STATIC_ASSERT((String::kMaxLength & 0x80000000) == 0);
+  __ SmiCompare(rbx, Smi::FromInt(String::kMaxLength));
+  __ j(above, &string_add_runtime);
+
+  // If result is not supposed to be flat, allocate a cons string object. If
+  // both strings are ascii the result is an ascii cons string.
+  // rax: first string
+  // rbx: length of resulting flat string
+  // rdx: second string
+  // r8: instance type of first string
+  // r9: instance type of second string
+  Label non_ascii, allocated, ascii_data;
+  __ movl(rcx, r8);
+  __ and_(rcx, r9);
+  STATIC_ASSERT(kStringEncodingMask == kAsciiStringTag);
+  __ testl(rcx, Immediate(kAsciiStringTag));
+  __ j(zero, &non_ascii);
+  __ bind(&ascii_data);
+  // Allocate an acsii cons string.
+  __ AllocateAsciiConsString(rcx, rdi, no_reg, &string_add_runtime);
+  __ bind(&allocated);
+  // Fill the fields of the cons string.
+  __ movq(FieldOperand(rcx, ConsString::kLengthOffset), rbx);
+  __ movq(FieldOperand(rcx, ConsString::kHashFieldOffset),
+          Immediate(String::kEmptyHashField));
+  __ movq(FieldOperand(rcx, ConsString::kFirstOffset), rax);
+  __ movq(FieldOperand(rcx, ConsString::kSecondOffset), rdx);
+  __ movq(rax, rcx);
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+  __ bind(&non_ascii);
+  // At least one of the strings is two-byte. Check whether it happens
+  // to contain only ascii characters.
+  // rcx: first instance type AND second instance type.
+  // r8: first instance type.
+  // r9: second instance type.
+  __ testb(rcx, Immediate(kAsciiDataHintMask));
+  __ j(not_zero, &ascii_data);
+  __ xor_(r8, r9);
+  STATIC_ASSERT(kAsciiStringTag != 0 && kAsciiDataHintTag != 0);
+  __ andb(r8, Immediate(kAsciiStringTag | kAsciiDataHintTag));
+  __ cmpb(r8, Immediate(kAsciiStringTag | kAsciiDataHintTag));
+  __ j(equal, &ascii_data);
+  // Allocate a two byte cons string.
+  __ AllocateConsString(rcx, rdi, no_reg, &string_add_runtime);
+  __ jmp(&allocated);
+
+  // Handle creating a flat result. First check that both strings are not
+  // external strings.
+  // rax: first string
+  // rbx: length of resulting flat string as smi
+  // rdx: second string
+  // r8: instance type of first string
+  // r9: instance type of first string
+  __ bind(&string_add_flat_result);
+  __ SmiToInteger32(rbx, rbx);
+  __ movl(rcx, r8);
+  __ and_(rcx, Immediate(kStringRepresentationMask));
+  __ cmpl(rcx, Immediate(kExternalStringTag));
+  __ j(equal, &string_add_runtime);
+  __ movl(rcx, r9);
+  __ and_(rcx, Immediate(kStringRepresentationMask));
+  __ cmpl(rcx, Immediate(kExternalStringTag));
+  __ j(equal, &string_add_runtime);
+  // Now check if both strings are ascii strings.
+  // rax: first string
+  // rbx: length of resulting flat string
+  // rdx: second string
+  // r8: instance type of first string
+  // r9: instance type of second string
+  Label non_ascii_string_add_flat_result;
+  STATIC_ASSERT(kStringEncodingMask == kAsciiStringTag);
+  __ testl(r8, Immediate(kAsciiStringTag));
+  __ j(zero, &non_ascii_string_add_flat_result);
+  __ testl(r9, Immediate(kAsciiStringTag));
+  __ j(zero, &string_add_runtime);
+
+  __ bind(&make_flat_ascii_string);
+  // Both strings are ascii strings. As they are short they are both flat.
+  __ AllocateAsciiString(rcx, rbx, rdi, r14, r11, &string_add_runtime);
+  // rcx: result string
+  __ movq(rbx, rcx);
+  // Locate first character of result.
+  __ addq(rcx, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  // Locate first character of first argument
+  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
+  __ addq(rax, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  // rax: first char of first argument
+  // rbx: result string
+  // rcx: first character of result
+  // rdx: second string
+  // rdi: length of first argument
+  StringHelper::GenerateCopyCharacters(masm, rcx, rax, rdi, true);
+  // Locate first character of second argument.
+  __ SmiToInteger32(rdi, FieldOperand(rdx, String::kLengthOffset));
+  __ addq(rdx, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  // rbx: result string
+  // rcx: next character of result
+  // rdx: first char of second argument
+  // rdi: length of second argument
+  StringHelper::GenerateCopyCharacters(masm, rcx, rdx, rdi, true);
+  __ movq(rax, rbx);
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+
+  // Handle creating a flat two byte result.
+  // rax: first string - known to be two byte
+  // rbx: length of resulting flat string
+  // rdx: second string
+  // r8: instance type of first string
+  // r9: instance type of first string
+  __ bind(&non_ascii_string_add_flat_result);
+  __ and_(r9, Immediate(kAsciiStringTag));
+  __ j(not_zero, &string_add_runtime);
+  // Both strings are two byte strings. As they are short they are both
+  // flat.
+  __ AllocateTwoByteString(rcx, rbx, rdi, r14, r11, &string_add_runtime);
+  // rcx: result string
+  __ movq(rbx, rcx);
+  // Locate first character of result.
+  __ addq(rcx, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  // Locate first character of first argument.
+  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
+  __ addq(rax, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  // rax: first char of first argument
+  // rbx: result string
+  // rcx: first character of result
+  // rdx: second argument
+  // rdi: length of first argument
+  StringHelper::GenerateCopyCharacters(masm, rcx, rax, rdi, false);
+  // Locate first character of second argument.
+  __ SmiToInteger32(rdi, FieldOperand(rdx, String::kLengthOffset));
+  __ addq(rdx, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  // rbx: result string
+  // rcx: next character of result
+  // rdx: first char of second argument
+  // rdi: length of second argument
+  StringHelper::GenerateCopyCharacters(masm, rcx, rdx, rdi, false);
+  __ movq(rax, rbx);
+  __ IncrementCounter(&Counters::string_add_native, 1);
+  __ ret(2 * kPointerSize);
+
+  // Just jump to runtime to add the two strings.
+  __ bind(&string_add_runtime);
+  __ TailCallRuntime(Runtime::kStringAdd, 2, 1);
+}
+
+
+void StringHelper::GenerateCopyCharacters(MacroAssembler* masm,
+                                          Register dest,
+                                          Register src,
+                                          Register count,
+                                          bool ascii) {
+  Label loop;
+  __ bind(&loop);
+  // This loop just copies one character at a time, as it is only used for very
+  // short strings.
+  if (ascii) {
+    __ movb(kScratchRegister, Operand(src, 0));
+    __ movb(Operand(dest, 0), kScratchRegister);
+    __ incq(src);
+    __ incq(dest);
+  } else {
+    __ movzxwl(kScratchRegister, Operand(src, 0));
+    __ movw(Operand(dest, 0), kScratchRegister);
+    __ addq(src, Immediate(2));
+    __ addq(dest, Immediate(2));
+  }
+  __ decl(count);
+  __ j(not_zero, &loop);
+}
+
+
+void StringHelper::GenerateCopyCharactersREP(MacroAssembler* masm,
+                                             Register dest,
+                                             Register src,
+                                             Register count,
+                                             bool ascii) {
+  // Copy characters using rep movs of doublewords. Align destination on 4 byte
+  // boundary before starting rep movs. Copy remaining characters after running
+  // rep movs.
+  // Count is positive int32, dest and src are character pointers.
+  ASSERT(dest.is(rdi));  // rep movs destination
+  ASSERT(src.is(rsi));  // rep movs source
+  ASSERT(count.is(rcx));  // rep movs count
+
+  // Nothing to do for zero characters.
+  Label done;
+  __ testl(count, count);
+  __ j(zero, &done);
+
+  // Make count the number of bytes to copy.
+  if (!ascii) {
+    STATIC_ASSERT(2 == sizeof(uc16));
+    __ addl(count, count);
+  }
+
+  // Don't enter the rep movs if there are less than 4 bytes to copy.
+  Label last_bytes;
+  __ testl(count, Immediate(~7));
+  __ j(zero, &last_bytes);
+
+  // Copy from edi to esi using rep movs instruction.
+  __ movl(kScratchRegister, count);
+  __ shr(count, Immediate(3));  // Number of doublewords to copy.
+  __ repmovsq();
+
+  // Find number of bytes left.
+  __ movl(count, kScratchRegister);
+  __ and_(count, Immediate(7));
+
+  // Check if there are more bytes to copy.
+  __ bind(&last_bytes);
+  __ testl(count, count);
+  __ j(zero, &done);
+
+  // Copy remaining characters.
+  Label loop;
+  __ bind(&loop);
+  __ movb(kScratchRegister, Operand(src, 0));
+  __ movb(Operand(dest, 0), kScratchRegister);
+  __ incq(src);
+  __ incq(dest);
+  __ decl(count);
+  __ j(not_zero, &loop);
+
+  __ bind(&done);
+}
+
+void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+                                                        Register c1,
+                                                        Register c2,
+                                                        Register scratch1,
+                                                        Register scratch2,
+                                                        Register scratch3,
+                                                        Register scratch4,
+                                                        Label* not_found) {
+  // Register scratch3 is the general scratch register in this function.
+  Register scratch = scratch3;
+
+  // Make sure that both characters are not digits as such strings has a
+  // different hash algorithm. Don't try to look for these in the symbol table.
+  Label not_array_index;
+  __ leal(scratch, Operand(c1, -'0'));
+  __ cmpl(scratch, Immediate(static_cast<int>('9' - '0')));
+  __ j(above, &not_array_index);
+  __ leal(scratch, Operand(c2, -'0'));
+  __ cmpl(scratch, Immediate(static_cast<int>('9' - '0')));
+  __ j(below_equal, not_found);
+
+  __ bind(&not_array_index);
+  // Calculate the two character string hash.
+  Register hash = scratch1;
+  GenerateHashInit(masm, hash, c1, scratch);
+  GenerateHashAddCharacter(masm, hash, c2, scratch);
+  GenerateHashGetHash(masm, hash, scratch);
+
+  // Collect the two characters in a register.
+  Register chars = c1;
+  __ shl(c2, Immediate(kBitsPerByte));
+  __ orl(chars, c2);
+
+  // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
+  // hash:  hash of two character string.
+
+  // Load the symbol table.
+  Register symbol_table = c2;
+  __ LoadRoot(symbol_table, Heap::kSymbolTableRootIndex);
+
+  // Calculate capacity mask from the symbol table capacity.
+  Register mask = scratch2;
+  __ SmiToInteger32(mask,
+                    FieldOperand(symbol_table, SymbolTable::kCapacityOffset));
+  __ decl(mask);
+
+  Register undefined = scratch4;
+  __ LoadRoot(undefined, Heap::kUndefinedValueRootIndex);
+
+  // Registers
+  // chars:        two character string, char 1 in byte 0 and char 2 in byte 1.
+  // hash:         hash of two character string (32-bit int)
+  // symbol_table: symbol table
+  // mask:         capacity mask (32-bit int)
+  // undefined:    undefined value
+  // scratch:      -
+
+  // Perform a number of probes in the symbol table.
+  static const int kProbes = 4;
+  Label found_in_symbol_table;
+  Label next_probe[kProbes];
+  for (int i = 0; i < kProbes; i++) {
+    // Calculate entry in symbol table.
+    __ movl(scratch, hash);
+    if (i > 0) {
+      __ addl(scratch, Immediate(SymbolTable::GetProbeOffset(i)));
+    }
+    __ andl(scratch, mask);
+
+    // Load the entry from the symble table.
+    Register candidate = scratch;  // Scratch register contains candidate.
+    STATIC_ASSERT(SymbolTable::kEntrySize == 1);
+    __ movq(candidate,
+            FieldOperand(symbol_table,
+                         scratch,
+                         times_pointer_size,
+                         SymbolTable::kElementsStartOffset));
+
+    // If entry is undefined no string with this hash can be found.
+    __ cmpq(candidate, undefined);
+    __ j(equal, not_found);
+
+    // If length is not 2 the string is not a candidate.
+    __ SmiCompare(FieldOperand(candidate, String::kLengthOffset),
+                  Smi::FromInt(2));
+    __ j(not_equal, &next_probe[i]);
+
+    // We use kScratchRegister as a temporary register in assumption that
+    // JumpIfInstanceTypeIsNotSequentialAscii does not use it implicitly
+    Register temp = kScratchRegister;
+
+    // Check that the candidate is a non-external ascii string.
+    __ movq(temp, FieldOperand(candidate, HeapObject::kMapOffset));
+    __ movzxbl(temp, FieldOperand(temp, Map::kInstanceTypeOffset));
+    __ JumpIfInstanceTypeIsNotSequentialAscii(
+        temp, temp, &next_probe[i]);
+
+    // Check if the two characters match.
+    __ movl(temp, FieldOperand(candidate, SeqAsciiString::kHeaderSize));
+    __ andl(temp, Immediate(0x0000ffff));
+    __ cmpl(chars, temp);
+    __ j(equal, &found_in_symbol_table);
+    __ bind(&next_probe[i]);
+  }
+
+  // No matching 2 character string found by probing.
+  __ jmp(not_found);
+
+  // Scratch register contains result when we fall through to here.
+  Register result = scratch;
+  __ bind(&found_in_symbol_table);
+  if (!result.is(rax)) {
+    __ movq(rax, result);
+  }
+}
+
+
+void StringHelper::GenerateHashInit(MacroAssembler* masm,
+                                    Register hash,
+                                    Register character,
+                                    Register scratch) {
+  // hash = character + (character << 10);
+  __ movl(hash, character);
+  __ shll(hash, Immediate(10));
+  __ addl(hash, character);
+  // hash ^= hash >> 6;
+  __ movl(scratch, hash);
+  __ sarl(scratch, Immediate(6));
+  __ xorl(hash, scratch);
+}
+
+
+void StringHelper::GenerateHashAddCharacter(MacroAssembler* masm,
+                                            Register hash,
+                                            Register character,
+                                            Register scratch) {
+  // hash += character;
+  __ addl(hash, character);
+  // hash += hash << 10;
+  __ movl(scratch, hash);
+  __ shll(scratch, Immediate(10));
+  __ addl(hash, scratch);
+  // hash ^= hash >> 6;
+  __ movl(scratch, hash);
+  __ sarl(scratch, Immediate(6));
+  __ xorl(hash, scratch);
+}
+
+
+void StringHelper::GenerateHashGetHash(MacroAssembler* masm,
+                                       Register hash,
+                                       Register scratch) {
+  // hash += hash << 3;
+  __ leal(hash, Operand(hash, hash, times_8, 0));
+  // hash ^= hash >> 11;
+  __ movl(scratch, hash);
+  __ sarl(scratch, Immediate(11));
+  __ xorl(hash, scratch);
+  // hash += hash << 15;
+  __ movl(scratch, hash);
+  __ shll(scratch, Immediate(15));
+  __ addl(hash, scratch);
+
+  // if (hash == 0) hash = 27;
+  Label hash_not_zero;
+  __ j(not_zero, &hash_not_zero);
+  __ movl(hash, Immediate(27));
+  __ bind(&hash_not_zero);
+}
+
+void SubStringStub::Generate(MacroAssembler* masm) {
+  Label runtime;
+
+  // Stack frame on entry.
+  //  rsp[0]: return address
+  //  rsp[8]: to
+  //  rsp[16]: from
+  //  rsp[24]: string
+
+  const int kToOffset = 1 * kPointerSize;
+  const int kFromOffset = kToOffset + kPointerSize;
+  const int kStringOffset = kFromOffset + kPointerSize;
+  const int kArgumentsSize = (kStringOffset + kPointerSize) - kToOffset;
+
+  // Make sure first argument is a string.
+  __ movq(rax, Operand(rsp, kStringOffset));
+  STATIC_ASSERT(kSmiTag == 0);
+  __ testl(rax, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+  Condition is_string = masm->IsObjectStringType(rax, rbx, rbx);
+  __ j(NegateCondition(is_string), &runtime);
+
+  // rax: string
+  // rbx: instance type
+  // Calculate length of sub string using the smi values.
+  Label result_longer_than_two;
+  __ movq(rcx, Operand(rsp, kToOffset));
+  __ movq(rdx, Operand(rsp, kFromOffset));
+  __ JumpIfNotBothPositiveSmi(rcx, rdx, &runtime);
+
+  __ SmiSub(rcx, rcx, rdx, NULL);  // Overflow doesn't happen.
+  __ cmpq(FieldOperand(rax, String::kLengthOffset), rcx);
+  Label return_rax;
+  __ j(equal, &return_rax);
+  // Special handling of sub-strings of length 1 and 2. One character strings
+  // are handled in the runtime system (looked up in the single character
+  // cache). Two character strings are looked for in the symbol cache.
+  __ SmiToInteger32(rcx, rcx);
+  __ cmpl(rcx, Immediate(2));
+  __ j(greater, &result_longer_than_two);
+  __ j(less, &runtime);
+
+  // Sub string of length 2 requested.
+  // rax: string
+  // rbx: instance type
+  // rcx: sub string length (value is 2)
+  // rdx: from index (smi)
+  __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &runtime);
+
+  // Get the two characters forming the sub string.
+  __ SmiToInteger32(rdx, rdx);  // From index is no longer smi.
+  __ movzxbq(rbx, FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize));
+  __ movzxbq(rcx,
+             FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize + 1));
+
+  // Try to lookup two character string in symbol table.
+  Label make_two_character_string;
+  StringHelper::GenerateTwoCharacterSymbolTableProbe(
+      masm, rbx, rcx, rax, rdx, rdi, r14, &make_two_character_string);
+  __ ret(3 * kPointerSize);
+
+  __ bind(&make_two_character_string);
+  // Setup registers for allocating the two character string.
+  __ movq(rax, Operand(rsp, kStringOffset));
+  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
+  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
+  __ Set(rcx, 2);
+
+  __ bind(&result_longer_than_two);
+
+  // rax: string
+  // rbx: instance type
+  // rcx: result string length
+  // Check for flat ascii string
+  Label non_ascii_flat;
+  __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &non_ascii_flat);
+
+  // Allocate the result.
+  __ AllocateAsciiString(rax, rcx, rbx, rdx, rdi, &runtime);
+
+  // rax: result string
+  // rcx: result string length
+  __ movq(rdx, rsi);  // esi used by following code.
+  // Locate first character of result.
+  __ lea(rdi, FieldOperand(rax, SeqAsciiString::kHeaderSize));
+  // Load string argument and locate character of sub string start.
+  __ movq(rsi, Operand(rsp, kStringOffset));
+  __ movq(rbx, Operand(rsp, kFromOffset));
+  {
+    SmiIndex smi_as_index = masm->SmiToIndex(rbx, rbx, times_1);
+    __ lea(rsi, Operand(rsi, smi_as_index.reg, smi_as_index.scale,
+                        SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  }
+
+  // rax: result string
+  // rcx: result length
+  // rdx: original value of rsi
+  // rdi: first character of result
+  // rsi: character of sub string start
+  StringHelper::GenerateCopyCharactersREP(masm, rdi, rsi, rcx, true);
+  __ movq(rsi, rdx);  // Restore rsi.
+  __ IncrementCounter(&Counters::sub_string_native, 1);
+  __ ret(kArgumentsSize);
+
+  __ bind(&non_ascii_flat);
+  // rax: string
+  // rbx: instance type & kStringRepresentationMask | kStringEncodingMask
+  // rcx: result string length
+  // Check for sequential two byte string
+  __ cmpb(rbx, Immediate(kSeqStringTag | kTwoByteStringTag));
+  __ j(not_equal, &runtime);
+
+  // Allocate the result.
+  __ AllocateTwoByteString(rax, rcx, rbx, rdx, rdi, &runtime);
+
+  // rax: result string
+  // rcx: result string length
+  __ movq(rdx, rsi);  // esi used by following code.
+  // Locate first character of result.
+  __ lea(rdi, FieldOperand(rax, SeqTwoByteString::kHeaderSize));
+  // Load string argument and locate character of sub string start.
+  __ movq(rsi, Operand(rsp, kStringOffset));
+  __ movq(rbx, Operand(rsp, kFromOffset));
+  {
+    SmiIndex smi_as_index = masm->SmiToIndex(rbx, rbx, times_2);
+    __ lea(rsi, Operand(rsi, smi_as_index.reg, smi_as_index.scale,
+                        SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  }
+
+  // rax: result string
+  // rcx: result length
+  // rdx: original value of rsi
+  // rdi: first character of result
+  // rsi: character of sub string start
+  StringHelper::GenerateCopyCharactersREP(masm, rdi, rsi, rcx, false);
+  __ movq(rsi, rdx);  // Restore esi.
+
+  __ bind(&return_rax);
+  __ IncrementCounter(&Counters::sub_string_native, 1);
+  __ ret(kArgumentsSize);
+
+  // Just jump to runtime to create the sub string.
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kSubString, 3, 1);
+}
+
+
+void StringCompareStub::GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
+                                                        Register left,
+                                                        Register right,
+                                                        Register scratch1,
+                                                        Register scratch2,
+                                                        Register scratch3,
+                                                        Register scratch4) {
+  // Ensure that you can always subtract a string length from a non-negative
+  // number (e.g. another length).
+  STATIC_ASSERT(String::kMaxLength < 0x7fffffff);
+
+  // Find minimum length and length difference.
+  __ movq(scratch1, FieldOperand(left, String::kLengthOffset));
+  __ movq(scratch4, scratch1);
+  __ SmiSub(scratch4,
+            scratch4,
+            FieldOperand(right, String::kLengthOffset),
+            NULL);
+  // Register scratch4 now holds left.length - right.length.
+  const Register length_difference = scratch4;
+  Label left_shorter;
+  __ j(less, &left_shorter);
+  // The right string isn't longer that the left one.
+  // Get the right string's length by subtracting the (non-negative) difference
+  // from the left string's length.
+  __ SmiSub(scratch1, scratch1, length_difference, NULL);
+  __ bind(&left_shorter);
+  // Register scratch1 now holds Min(left.length, right.length).
+  const Register min_length = scratch1;
+
+  Label compare_lengths;
+  // If min-length is zero, go directly to comparing lengths.
+  __ SmiTest(min_length);
+  __ j(zero, &compare_lengths);
+
+  __ SmiToInteger32(min_length, min_length);
+
+  // Registers scratch2 and scratch3 are free.
+  Label result_not_equal;
+  Label loop;
+  {
+    // Check characters 0 .. min_length - 1 in a loop.
+    // Use scratch3 as loop index, min_length as limit and scratch2
+    // for computation.
+    const Register index = scratch3;
+    __ movl(index, Immediate(0));  // Index into strings.
+    __ bind(&loop);
+    // Compare characters.
+    // TODO(lrn): Could we load more than one character at a time?
+    __ movb(scratch2, FieldOperand(left,
+                                   index,
+                                   times_1,
+                                   SeqAsciiString::kHeaderSize));
+    // Increment index and use -1 modifier on next load to give
+    // the previous load extra time to complete.
+    __ addl(index, Immediate(1));
+    __ cmpb(scratch2, FieldOperand(right,
+                                   index,
+                                   times_1,
+                                   SeqAsciiString::kHeaderSize - 1));
+    __ j(not_equal, &result_not_equal);
+    __ cmpl(index, min_length);
+    __ j(not_equal, &loop);
+  }
+  // Completed loop without finding different characters.
+  // Compare lengths (precomputed).
+  __ bind(&compare_lengths);
+  __ SmiTest(length_difference);
+  __ j(not_zero, &result_not_equal);
+
+  // Result is EQUAL.
+  __ Move(rax, Smi::FromInt(EQUAL));
+  __ ret(0);
+
+  Label result_greater;
+  __ bind(&result_not_equal);
+  // Unequal comparison of left to right, either character or length.
+  __ j(greater, &result_greater);
+
+  // Result is LESS.
+  __ Move(rax, Smi::FromInt(LESS));
+  __ ret(0);
+
+  // Result is GREATER.
+  __ bind(&result_greater);
+  __ Move(rax, Smi::FromInt(GREATER));
+  __ ret(0);
+}
+
+
+void StringCompareStub::Generate(MacroAssembler* masm) {
+  Label runtime;
+
+  // Stack frame on entry.
+  //  rsp[0]: return address
+  //  rsp[8]: right string
+  //  rsp[16]: left string
+
+  __ movq(rdx, Operand(rsp, 2 * kPointerSize));  // left
+  __ movq(rax, Operand(rsp, 1 * kPointerSize));  // right
+
+  // Check for identity.
+  Label not_same;
+  __ cmpq(rdx, rax);
+  __ j(not_equal, &not_same);
+  __ Move(rax, Smi::FromInt(EQUAL));
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  __ ret(2 * kPointerSize);
+
+  __ bind(&not_same);
+
+  // Check that both are sequential ASCII strings.
+  __ JumpIfNotBothSequentialAsciiStrings(rdx, rax, rcx, rbx, &runtime);
+
+  // Inline comparison of ascii strings.
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  // Drop arguments from the stack
+  __ pop(rcx);
+  __ addq(rsp, Immediate(2 * kPointerSize));
+  __ push(rcx);
+  GenerateCompareFlatAsciiStrings(masm, rdx, rax, rcx, rbx, rdi, r8);
+
+  // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
+  // tagged as a small integer.
+  __ bind(&runtime);
+  __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
+}
+
+#undef __
+
+} }  // namespace v8::internal
+
+#endif  // V8_TARGET_ARCH_X64
diff --git a/deps/v8/src/x64/code-stubs-x64.h b/deps/v8/src/x64/code-stubs-x64.h
new file mode 100644
index 0000000000..18213b93e6
--- /dev/null
+++ b/deps/v8/src/x64/code-stubs-x64.h
@@ -0,0 +1,389 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_X64_CODE_STUBS_X64_H_
+#define V8_X64_CODE_STUBS_X64_H_
+
+#include "ic-inl.h"
+#include "type-info.h"
+
+namespace v8 {
+namespace internal {
+
+
+// Compute a transcendental math function natively, or call the
+// TranscendentalCache runtime function.
+class TranscendentalCacheStub: public CodeStub {
+ public:
+  explicit TranscendentalCacheStub(TranscendentalCache::Type type)
+      : type_(type) {}
+  void Generate(MacroAssembler* masm);
+ private:
+  TranscendentalCache::Type type_;
+  Major MajorKey() { return TranscendentalCache; }
+  int MinorKey() { return type_; }
+  Runtime::FunctionId RuntimeFunction();
+  void GenerateOperation(MacroAssembler* masm, Label* on_nan_result);
+};
+
+
+class ToBooleanStub: public CodeStub {
+ public:
+  ToBooleanStub() { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  Major MajorKey() { return ToBoolean; }
+  int MinorKey() { return 0; }
+};
+
+
+// Flag that indicates how to generate code for the stub GenericBinaryOpStub.
+enum GenericBinaryFlags {
+  NO_GENERIC_BINARY_FLAGS = 0,
+  NO_SMI_CODE_IN_STUB = 1 << 0  // Omit smi code in stub.
+};
+
+
+class GenericBinaryOpStub: public CodeStub {
+ public:
+  GenericBinaryOpStub(Token::Value op,
+                      OverwriteMode mode,
+                      GenericBinaryFlags flags,
+                      TypeInfo operands_type = TypeInfo::Unknown())
+      : op_(op),
+        mode_(mode),
+        flags_(flags),
+        args_in_registers_(false),
+        args_reversed_(false),
+        static_operands_type_(operands_type),
+        runtime_operands_type_(BinaryOpIC::DEFAULT),
+        name_(NULL) {
+    ASSERT(OpBits::is_valid(Token::NUM_TOKENS));
+  }
+
+  GenericBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info)
+      : op_(OpBits::decode(key)),
+        mode_(ModeBits::decode(key)),
+        flags_(FlagBits::decode(key)),
+        args_in_registers_(ArgsInRegistersBits::decode(key)),
+        args_reversed_(ArgsReversedBits::decode(key)),
+        static_operands_type_(TypeInfo::ExpandedRepresentation(
+            StaticTypeInfoBits::decode(key))),
+        runtime_operands_type_(type_info),
+        name_(NULL) {
+  }
+
+  // Generate code to call the stub with the supplied arguments. This will add
+  // code at the call site to prepare arguments either in registers or on the
+  // stack together with the actual call.
+  void GenerateCall(MacroAssembler* masm, Register left, Register right);
+  void GenerateCall(MacroAssembler* masm, Register left, Smi* right);
+  void GenerateCall(MacroAssembler* masm, Smi* left, Register right);
+
+  bool ArgsInRegistersSupported() {
+    return (op_ == Token::ADD) || (op_ == Token::SUB)
+        || (op_ == Token::MUL) || (op_ == Token::DIV);
+  }
+
+ private:
+  Token::Value op_;
+  OverwriteMode mode_;
+  GenericBinaryFlags flags_;
+  bool args_in_registers_;  // Arguments passed in registers not on the stack.
+  bool args_reversed_;  // Left and right argument are swapped.
+
+  // Number type information of operands, determined by code generator.
+  TypeInfo static_operands_type_;
+
+  // Operand type information determined at runtime.
+  BinaryOpIC::TypeInfo runtime_operands_type_;
+
+  char* name_;
+
+  const char* GetName();
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("GenericBinaryOpStub %d (op %s), "
+           "(mode %d, flags %d, registers %d, reversed %d, only_numbers %s)\n",
+           MinorKey(),
+           Token::String(op_),
+           static_cast<int>(mode_),
+           static_cast<int>(flags_),
+           static_cast<int>(args_in_registers_),
+           static_cast<int>(args_reversed_),
+           static_operands_type_.ToString());
+  }
+#endif
+
+  // Minor key encoding in 17 bits TTNNNFRAOOOOOOOMM.
+  class ModeBits: public BitField<OverwriteMode, 0, 2> {};
+  class OpBits: public BitField<Token::Value, 2, 7> {};
+  class ArgsInRegistersBits: public BitField<bool, 9, 1> {};
+  class ArgsReversedBits: public BitField<bool, 10, 1> {};
+  class FlagBits: public BitField<GenericBinaryFlags, 11, 1> {};
+  class StaticTypeInfoBits: public BitField<int, 12, 3> {};
+  class RuntimeTypeInfoBits: public BitField<BinaryOpIC::TypeInfo, 15, 2> {};
+
+  Major MajorKey() { return GenericBinaryOp; }
+  int MinorKey() {
+    // Encode the parameters in a unique 18 bit value.
+    return OpBits::encode(op_)
+           | ModeBits::encode(mode_)
+           | FlagBits::encode(flags_)
+           | ArgsInRegistersBits::encode(args_in_registers_)
+           | ArgsReversedBits::encode(args_reversed_)
+           | StaticTypeInfoBits::encode(
+               static_operands_type_.ThreeBitRepresentation())
+           | RuntimeTypeInfoBits::encode(runtime_operands_type_);
+  }
+
+  void Generate(MacroAssembler* masm);
+  void GenerateSmiCode(MacroAssembler* masm, Label* slow);
+  void GenerateLoadArguments(MacroAssembler* masm);
+  void GenerateReturn(MacroAssembler* masm);
+  void GenerateRegisterArgsPush(MacroAssembler* masm);
+  void GenerateTypeTransition(MacroAssembler* masm);
+
+  bool IsOperationCommutative() {
+    return (op_ == Token::ADD) || (op_ == Token::MUL);
+  }
+
+  void SetArgsInRegisters() { args_in_registers_ = true; }
+  void SetArgsReversed() { args_reversed_ = true; }
+  bool HasSmiCodeInStub() { return (flags_ & NO_SMI_CODE_IN_STUB) == 0; }
+  bool HasArgsInRegisters() { return args_in_registers_; }
+  bool HasArgsReversed() { return args_reversed_; }
+
+  bool ShouldGenerateSmiCode() {
+    return HasSmiCodeInStub() &&
+        runtime_operands_type_ != BinaryOpIC::HEAP_NUMBERS &&
+        runtime_operands_type_ != BinaryOpIC::STRINGS;
+  }
+
+  bool ShouldGenerateFPCode() {
+    return runtime_operands_type_ != BinaryOpIC::STRINGS;
+  }
+
+  virtual int GetCodeKind() { return Code::BINARY_OP_IC; }
+
+  virtual InlineCacheState GetICState() {
+    return BinaryOpIC::ToState(runtime_operands_type_);
+  }
+
+  friend class CodeGenerator;
+};
+
+class StringHelper : public AllStatic {
+ public:
+  // Generate code for copying characters using a simple loop. This should only
+  // be used in places where the number of characters is small and the
+  // additional setup and checking in GenerateCopyCharactersREP adds too much
+  // overhead. Copying of overlapping regions is not supported.
+  static void GenerateCopyCharacters(MacroAssembler* masm,
+                                     Register dest,
+                                     Register src,
+                                     Register count,
+                                     bool ascii);
+
+  // Generate code for copying characters using the rep movs instruction.
+  // Copies rcx characters from rsi to rdi. Copying of overlapping regions is
+  // not supported.
+  static void GenerateCopyCharactersREP(MacroAssembler* masm,
+                                        Register dest,     // Must be rdi.
+                                        Register src,      // Must be rsi.
+                                        Register count,    // Must be rcx.
+                                        bool ascii);
+
+
+  // Probe the symbol table for a two character string. If the string is
+  // not found by probing a jump to the label not_found is performed. This jump
+  // does not guarantee that the string is not in the symbol table. If the
+  // string is found the code falls through with the string in register rax.
+  static void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+                                                   Register c1,
+                                                   Register c2,
+                                                   Register scratch1,
+                                                   Register scratch2,
+                                                   Register scratch3,
+                                                   Register scratch4,
+                                                   Label* not_found);
+
+  // Generate string hash.
+  static void GenerateHashInit(MacroAssembler* masm,
+                               Register hash,
+                               Register character,
+                               Register scratch);
+  static void GenerateHashAddCharacter(MacroAssembler* masm,
+                                       Register hash,
+                                       Register character,
+                                       Register scratch);
+  static void GenerateHashGetHash(MacroAssembler* masm,
+                                  Register hash,
+                                  Register scratch);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
+};
+
+
+// Flag that indicates how to generate code for the stub StringAddStub.
+enum StringAddFlags {
+  NO_STRING_ADD_FLAGS = 0,
+  NO_STRING_CHECK_IN_STUB = 1 << 0  // Omit string check in stub.
+};
+
+
+class StringAddStub: public CodeStub {
+ public:
+  explicit StringAddStub(StringAddFlags flags) {
+    string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
+  }
+
+ private:
+  Major MajorKey() { return StringAdd; }
+  int MinorKey() { return string_check_ ? 0 : 1; }
+
+  void Generate(MacroAssembler* masm);
+
+  // Should the stub check whether arguments are strings?
+  bool string_check_;
+};
+
+
+class SubStringStub: public CodeStub {
+ public:
+  SubStringStub() {}
+
+ private:
+  Major MajorKey() { return SubString; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+};
+
+
+class StringCompareStub: public CodeStub {
+ public:
+  explicit StringCompareStub() {}
+
+  // Compare two flat ascii strings and returns result in rax after popping two
+  // arguments from the stack.
+  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
+                                              Register left,
+                                              Register right,
+                                              Register scratch1,
+                                              Register scratch2,
+                                              Register scratch3,
+                                              Register scratch4);
+
+ private:
+  Major MajorKey() { return StringCompare; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+};
+
+
+class NumberToStringStub: public CodeStub {
+ public:
+  NumberToStringStub() { }
+
+  // Generate code to do a lookup in the number string cache. If the number in
+  // the register object is found in the cache the generated code falls through
+  // with the result in the result register. The object and the result register
+  // can be the same. If the number is not found in the cache the code jumps to
+  // the label not_found with only the content of register object unchanged.
+  static void GenerateLookupNumberStringCache(MacroAssembler* masm,
+                                              Register object,
+                                              Register result,
+                                              Register scratch1,
+                                              Register scratch2,
+                                              bool object_is_smi,
+                                              Label* not_found);
+
+ private:
+  static void GenerateConvertHashCodeToIndex(MacroAssembler* masm,
+                                             Register hash,
+                                             Register mask);
+
+  Major MajorKey() { return NumberToString; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+
+  const char* GetName() { return "NumberToStringStub"; }
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("NumberToStringStub\n");
+  }
+#endif
+};
+
+
+class RecordWriteStub : public CodeStub {
+ public:
+  RecordWriteStub(Register object, Register addr, Register scratch)
+      : object_(object), addr_(addr), scratch_(scratch) { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  Register object_;
+  Register addr_;
+  Register scratch_;
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("RecordWriteStub (object reg %d), (addr reg %d), (scratch reg %d)\n",
+           object_.code(), addr_.code(), scratch_.code());
+  }
+#endif
+
+  // Minor key encoding in 12 bits. 4 bits for each of the three
+  // registers (object, address and scratch) OOOOAAAASSSS.
+  class ScratchBits : public BitField<uint32_t, 0, 4> {};
+  class AddressBits : public BitField<uint32_t, 4, 4> {};
+  class ObjectBits : public BitField<uint32_t, 8, 4> {};
+
+  Major MajorKey() { return RecordWrite; }
+
+  int MinorKey() {
+    // Encode the registers.
+    return ObjectBits::encode(object_.code()) |
+           AddressBits::encode(addr_.code()) |
+           ScratchBits::encode(scratch_.code());
+  }
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_X64_CODE_STUBS_X64_H_
diff --git a/deps/v8/src/x64/codegen-x64.cc b/deps/v8/src/x64/codegen-x64.cc
index e545ffa3dc..b1dd45e206 100644
--- a/deps/v8/src/x64/codegen-x64.cc
+++ b/deps/v8/src/x64/codegen-x64.cc
@@ -30,6 +30,7 @@
 #if defined(V8_TARGET_ARCH_X64)
 
 #include "bootstrapper.h"
+#include "code-stubs.h"
 #include "codegen-inl.h"
 #include "compiler.h"
 #include "debug.h"
@@ -807,55 +808,6 @@ void CodeGenerator::ToBoolean(ControlDestination* dest) {
 }
 
 
-class FloatingPointHelper : public AllStatic {
- public:
-  // Load the operands from rdx and rax into xmm0 and xmm1, as doubles.
-  // If the operands are not both numbers, jump to not_numbers.
-  // Leaves rdx and rax unchanged.  SmiOperands assumes both are smis.
-  // NumberOperands assumes both are smis or heap numbers.
-  static void LoadSSE2SmiOperands(MacroAssembler* masm);
-  static void LoadSSE2NumberOperands(MacroAssembler* masm);
-  static void LoadSSE2UnknownOperands(MacroAssembler* masm,
-                                      Label* not_numbers);
-
-  // Takes the operands in rdx and rax and loads them as integers in rax
-  // and rcx.
-  static void LoadAsIntegers(MacroAssembler* masm,
-                             Label* operand_conversion_failure,
-                             Register heap_number_map);
-  // As above, but we know the operands to be numbers. In that case,
-  // conversion can't fail.
-  static void LoadNumbersAsIntegers(MacroAssembler* masm);
-};
-
-
-const char* GenericBinaryOpStub::GetName() {
-  if (name_ != NULL) return name_;
-  const int kMaxNameLength = 100;
-  name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);
-  if (name_ == NULL) return "OOM";
-  const char* op_name = Token::Name(op_);
-  const char* overwrite_name;
-  switch (mode_) {
-    case NO_OVERWRITE: overwrite_name = "Alloc"; break;
-    case OVERWRITE_RIGHT: overwrite_name = "OverwriteRight"; break;
-    case OVERWRITE_LEFT: overwrite_name = "OverwriteLeft"; break;
-    default: overwrite_name = "UnknownOverwrite"; break;
-  }
-
-  OS::SNPrintF(Vector<char>(name_, kMaxNameLength),
-               "GenericBinaryOpStub_%s_%s%s_%s%s_%s_%s",
-               op_name,
-               overwrite_name,
-               (flags_ & NO_SMI_CODE_IN_STUB) ? "_NoSmiInStub" : "",
-               args_in_registers_ ? "RegArgs" : "StackArgs",
-               args_reversed_ ? "_R" : "",
-               static_operands_type_.ToString(),
-               BinaryOpIC::GetName(runtime_operands_type_));
-  return name_;
-}
-
-
 // Call the specialized stub for a binary operation.
 class DeferredInlineBinaryOperation: public DeferredCode {
  public:
@@ -1072,7 +1024,7 @@ void CodeGenerator::GenericBinaryOperation(BinaryOperation* expr,
                              overwrite_mode,
                              NO_SMI_CODE_IN_STUB,
                              operands_type);
-    answer = stub.GenerateCall(masm_, frame_, &left, &right);
+    answer = GenerateGenericBinaryOpStubCall(&stub, &left, &right);
   } else if (right_is_smi_constant) {
     answer = ConstantSmiBinaryOperation(expr, &left, right.handle(),
                                         false, overwrite_mode);
@@ -1095,7 +1047,7 @@ void CodeGenerator::GenericBinaryOperation(BinaryOperation* expr,
                                overwrite_mode,
                                NO_GENERIC_BINARY_FLAGS,
                                operands_type);
-      answer = stub.GenerateCall(masm_, frame_, &left, &right);
+      answer = GenerateGenericBinaryOpStubCall(&stub, &left, &right);
     }
   }
 
@@ -2038,41 +1990,6 @@ void CodeGenerator::Comparison(AstNode* node,
     ConstantSmiComparison(cc, strict, dest, &left_side, &right_side,
                           left_side_constant_smi, right_side_constant_smi,
                           is_loop_condition);
-  } else if (cc == equal &&
-             (left_side_constant_null || right_side_constant_null)) {
-    // To make null checks efficient, we check if either the left side or
-    // the right side is the constant 'null'.
-    // If so, we optimize the code by inlining a null check instead of
-    // calling the (very) general runtime routine for checking equality.
-    Result operand = left_side_constant_null ? right_side : left_side;
-    right_side.Unuse();
-    left_side.Unuse();
-    operand.ToRegister();
-    __ CompareRoot(operand.reg(), Heap::kNullValueRootIndex);
-    if (strict) {
-      operand.Unuse();
-      dest->Split(equal);
-    } else {
-      // The 'null' value is only equal to 'undefined' if using non-strict
-      // comparisons.
-      dest->true_target()->Branch(equal);
-      __ CompareRoot(operand.reg(), Heap::kUndefinedValueRootIndex);
-      dest->true_target()->Branch(equal);
-      Condition is_smi = masm_->CheckSmi(operand.reg());
-      dest->false_target()->Branch(is_smi);
-
-      // It can be an undetectable object.
-      // Use a scratch register in preference to spilling operand.reg().
-      Result temp = allocator()->Allocate();
-      ASSERT(temp.is_valid());
-      __ movq(temp.reg(),
-              FieldOperand(operand.reg(), HeapObject::kMapOffset));
-      __ testb(FieldOperand(temp.reg(), Map::kBitFieldOffset),
-               Immediate(1 << Map::kIsUndetectable));
-      temp.Unuse();
-      operand.Unuse();
-      dest->Split(not_zero);
-    }
   } else if (left_side_constant_1_char_string ||
              right_side_constant_1_char_string) {
     if (left_side_constant_1_char_string && right_side_constant_1_char_string) {
@@ -2616,8 +2533,10 @@ void CodeGenerator::CallApplyLazy(Expression* applicand,
       __ j(is_smi, &build_args);
       __ CmpObjectType(rax, JS_FUNCTION_TYPE, rcx);
       __ j(not_equal, &build_args);
+      __ movq(rcx, FieldOperand(rax, JSFunction::kCodeEntryOffset));
+      __ subq(rcx, Immediate(Code::kHeaderSize - kHeapObjectTag));
       Handle<Code> apply_code(Builtins::builtin(Builtins::FunctionApply));
-      __ Cmp(FieldOperand(rax, JSFunction::kCodeOffset), apply_code);
+      __ Cmp(rcx, apply_code);
       __ j(not_equal, &build_args);
 
       // Check that applicand is a function.
@@ -4800,8 +4719,10 @@ void DeferredRegExpLiteral::Generate() {
 
 class DeferredAllocateInNewSpace: public DeferredCode {
  public:
-  DeferredAllocateInNewSpace(int size, Register target)
-    : size_(size), target_(target) {
+  DeferredAllocateInNewSpace(int size,
+                             Register target,
+                             int registers_to_save = 0)
+    : size_(size), target_(target), registers_to_save_(registers_to_save) {
     ASSERT(size >= kPointerSize && size <= Heap::MaxObjectSizeInNewSpace());
     set_comment("[ DeferredAllocateInNewSpace");
   }
@@ -4810,15 +4731,28 @@ class DeferredAllocateInNewSpace: public DeferredCode {
  private:
   int size_;
   Register target_;
+  int registers_to_save_;
 };
 
 
 void DeferredAllocateInNewSpace::Generate() {
+  for (int i = 0; i < kNumRegs; i++) {
+    if (registers_to_save_ & (1 << i)) {
+      Register save_register = { i };
+      __ push(save_register);
+    }
+  }
   __ Push(Smi::FromInt(size_));
   __ CallRuntime(Runtime::kAllocateInNewSpace, 1);
   if (!target_.is(rax)) {
     __ movq(target_, rax);
   }
+  for (int i = kNumRegs - 1; i >= 0; i--) {
+    if (registers_to_save_ & (1 << i)) {
+      Register save_register = { i };
+      __ pop(save_register);
+    }
+  }
 }
 
 
@@ -4989,12 +4923,18 @@ void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
   frame_->Push(node->constant_elements());
   int length = node->values()->length();
   Result clone;
-  if (node->depth() > 1) {
+  if (node->constant_elements()->map() == Heap::fixed_cow_array_map()) {
+    FastCloneShallowArrayStub stub(
+        FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS, length);
+    clone = frame_->CallStub(&stub, 3);
+    __ IncrementCounter(&Counters::cow_arrays_created_stub, 1);
+  } else if (node->depth() > 1) {
     clone = frame_->CallRuntime(Runtime::kCreateArrayLiteral, 3);
-  } else if (length > FastCloneShallowArrayStub::kMaximumLength) {
+  } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     clone = frame_->CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   } else {
-    FastCloneShallowArrayStub stub(length);
+    FastCloneShallowArrayStub stub(
+        FastCloneShallowArrayStub::CLONE_ELEMENTS, length);
     clone = frame_->CallStub(&stub, 3);
   }
   frame_->Push(&clone);
@@ -5004,12 +4944,9 @@ void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
   for (int i = 0; i < length; i++) {
     Expression* value = node->values()->at(i);
 
-    // If value is a literal the property value is already set in the
-    // boilerplate object.
-    if (value->AsLiteral() != NULL) continue;
-    // If value is a materialized literal the property value is already set
-    // in the boilerplate object if it is simple.
-    if (CompileTimeValue::IsCompileTimeValue(value)) continue;
+    if (!CompileTimeValue::ArrayLiteralElementNeedsInitialization(value)) {
+      continue;
+    }
 
     // The property must be set by generated code.
     Load(value);
@@ -5072,12 +5009,9 @@ void CodeGenerator::EmitSlotAssignment(Assignment* node) {
     Load(node->value());
 
     // Perform the binary operation.
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
     // Construct the implicit binary operation.
-    BinaryOperation expr(node, node->binary_op(), node->target(),
-                         node->value());
+    BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
@@ -5164,12 +5098,9 @@ void CodeGenerator::EmitNamedPropertyAssignment(Assignment* node) {
     frame()->Push(&value);
     Load(node->value());
 
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
     // Construct the implicit binary operation.
-    BinaryOperation expr(node, node->binary_op(), node->target(),
-                         node->value());
+    BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
@@ -5267,11 +5198,8 @@ void CodeGenerator::EmitKeyedPropertyAssignment(Assignment* node) {
     Load(node->value());
 
     // Perform the binary operation.
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
-    BinaryOperation expr(node, node->binary_op(), node->target(),
-                         node->value());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
+    BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
@@ -5674,11 +5602,10 @@ void CodeGenerator::VisitCallNew(CallNew* node) {
   // actual function to call is resolved after the arguments have been
   // evaluated.
 
-  // Compute function to call and use the global object as the
-  // receiver. There is no need to use the global proxy here because
-  // it will always be replaced with a newly allocated object.
+  // Push constructor on the stack.  If it's not a function it's used as
+  // receiver for CALL_NON_FUNCTION, otherwise the value on the stack is
+  // ignored.
   Load(node->expression());
-  LoadGlobal();
 
   // Push the arguments ("left-to-right") on the stack.
   ZoneList<Expression*>* args = node->arguments();
@@ -5691,8 +5618,7 @@ void CodeGenerator::VisitCallNew(CallNew* node) {
   // constructor invocation.
   CodeForSourcePosition(node->position());
   Result result = frame_->CallConstructor(arg_count);
-  // Replace the function on the stack with the result.
-  frame_->SetElementAt(0, &result);
+  frame_->Push(&result);
 }
 
 
@@ -6603,6 +6529,86 @@ void CodeGenerator::GenerateRegExpConstructResult(ZoneList<Expression*>* args) {
 }
 
 
+void CodeGenerator::GenerateRegExpCloneResult(ZoneList<Expression*>* args) {
+  ASSERT_EQ(1, args->length());
+
+  Load(args->at(0));
+  Result object_result = frame_->Pop();
+  object_result.ToRegister(rax);
+  object_result.Unuse();
+  {
+    VirtualFrame::SpilledScope spilled_scope;
+
+    Label done;
+    __ JumpIfSmi(rax, &done);
+
+    // Load JSRegExpResult map into rdx.
+    // Arguments to this function should be results of calling RegExp exec,
+    // which is either an unmodified JSRegExpResult or null. Anything not having
+    // the unmodified JSRegExpResult map is returned unmodified.
+    // This also ensures that elements are fast.
+
+    __ movq(rdx, ContextOperand(rsi, Context::GLOBAL_INDEX));
+    __ movq(rdx, FieldOperand(rdx, GlobalObject::kGlobalContextOffset));
+    __ movq(rdx, ContextOperand(rdx, Context::REGEXP_RESULT_MAP_INDEX));
+    __ cmpq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ j(not_equal, &done);
+
+    if (FLAG_debug_code) {
+      // Check that object really has empty properties array, as the map
+      // should guarantee.
+      __ CompareRoot(FieldOperand(rax, JSObject::kPropertiesOffset),
+                     Heap::kEmptyFixedArrayRootIndex);
+      __ Check(equal, "JSRegExpResult: default map but non-empty properties.");
+    }
+
+    DeferredAllocateInNewSpace* allocate_fallback =
+        new DeferredAllocateInNewSpace(JSRegExpResult::kSize,
+                                       rbx,
+                                       rdx.bit() | rax.bit());
+
+    // All set, copy the contents to a new object.
+    __ AllocateInNewSpace(JSRegExpResult::kSize,
+                          rbx,
+                          no_reg,
+                          no_reg,
+                          allocate_fallback->entry_label(),
+                          TAG_OBJECT);
+    __ bind(allocate_fallback->exit_label());
+
+    STATIC_ASSERT(JSRegExpResult::kSize % (2 * kPointerSize) == 0);
+    // There is an even number of fields, so unroll the loop once
+    // for efficiency.
+    for (int i = 0; i < JSRegExpResult::kSize; i += 2 * kPointerSize) {
+      STATIC_ASSERT(JSObject::kMapOffset % (2 * kPointerSize) == 0);
+      if (i != JSObject::kMapOffset) {
+        // The map was already loaded into edx.
+        __ movq(rdx, FieldOperand(rax, i));
+      }
+      __ movq(rcx, FieldOperand(rax, i + kPointerSize));
+
+      STATIC_ASSERT(JSObject::kElementsOffset % (2 * kPointerSize) == 0);
+      if (i == JSObject::kElementsOffset) {
+        // If the elements array isn't empty, make it copy-on-write
+        // before copying it.
+        Label empty;
+        __ CompareRoot(rdx, Heap::kEmptyFixedArrayRootIndex);
+        __ j(equal, &empty);
+        __ LoadRoot(kScratchRegister, Heap::kFixedCOWArrayMapRootIndex);
+        __ movq(FieldOperand(rdx, HeapObject::kMapOffset), kScratchRegister);
+        __ bind(&empty);
+      }
+      __ movq(FieldOperand(rbx, i), rdx);
+      __ movq(FieldOperand(rbx, i + kPointerSize), rcx);
+    }
+    __ movq(rax, rbx);
+
+    __ bind(&done);
+  }
+  frame_->Push(rax);
+}
+
+
 class DeferredSearchCache: public DeferredCode {
  public:
   DeferredSearchCache(Register dst,
@@ -6875,7 +6881,7 @@ void CodeGenerator::GenerateSwapElements(ZoneList<Expression*>* args) {
            Immediate(KeyedLoadIC::kSlowCaseBitFieldMask));
   deferred->Branch(not_zero);
 
-  // Check the object's elements are in fast case.
+  // Check the object's elements are in fast case and writable.
   __ movq(tmp1.reg(), FieldOperand(object.reg(), JSObject::kElementsOffset));
   __ CompareRoot(FieldOperand(tmp1.reg(), HeapObject::kMapOffset),
                  Heap::kFixedArrayMapRootIndex);
@@ -7217,6 +7223,34 @@ void CodeGenerator::GenerateIsRegExpEquivalent(ZoneList<Expression*>* args) {
 }
 
 
+void CodeGenerator::GenerateHasCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+  Load(args->at(0));
+  Result value = frame_->Pop();
+  value.ToRegister();
+  ASSERT(value.is_valid());
+  __ testl(FieldOperand(value.reg(), String::kHashFieldOffset),
+           Immediate(String::kContainsCachedArrayIndexMask));
+  value.Unuse();
+  destination()->Split(zero);
+}
+
+
+void CodeGenerator::GenerateGetCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+  Load(args->at(0));
+  Result string = frame_->Pop();
+  string.ToRegister();
+
+  Result number = allocator()->Allocate();
+  ASSERT(number.is_valid());
+  __ movl(number.reg(), FieldOperand(string.reg(), String::kHashFieldOffset));
+  __ IndexFromHash(number.reg(), number.reg());
+  string.Unuse();
+  frame_->Push(&number);
+}
+
+
 void CodeGenerator::VisitCallRuntime(CallRuntime* node) {
   if (CheckForInlineRuntimeCall(node)) {
     return;
@@ -7345,9 +7379,7 @@ void CodeGenerator::VisitUnaryOperation(UnaryOperation* node) {
     }
 
   } else {
-    bool can_overwrite =
-      (node->expression()->AsBinaryOperation() != NULL &&
-       node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool can_overwrite = node->expression()->ResultOverwriteAllowed();
     UnaryOverwriteMode overwrite =
         can_overwrite ? UNARY_OVERWRITE : UNARY_NO_OVERWRITE;
     bool no_negative_zero = node->expression()->no_negative_zero();
@@ -7765,11 +7797,9 @@ void CodeGenerator::VisitBinaryOperation(BinaryOperation* node) {
     // NOTE: The code below assumes that the slow cases (calls to runtime)
     // never return a constant/immutable object.
     OverwriteMode overwrite_mode = NO_OVERWRITE;
-    if (node->left()->AsBinaryOperation() != NULL &&
-        node->left()->AsBinaryOperation()->ResultOverwriteAllowed()) {
+    if (node->left()->ResultOverwriteAllowed()) {
       overwrite_mode = OVERWRITE_LEFT;
-    } else if (node->right()->AsBinaryOperation() != NULL &&
-               node->right()->AsBinaryOperation()->ResultOverwriteAllowed()) {
+    } else if (node->right()->ResultOverwriteAllowed()) {
       overwrite_mode = OVERWRITE_RIGHT;
     }
 
@@ -7955,6 +7985,40 @@ void CodeGenerator::VisitCompareOperation(CompareOperation* node) {
 }
 
 
+void CodeGenerator::VisitCompareToNull(CompareToNull* node) {
+  Comment cmnt(masm_, "[ CompareToNull");
+
+  Load(node->expression());
+  Result operand = frame_->Pop();
+  operand.ToRegister();
+  __ CompareRoot(operand.reg(), Heap::kNullValueRootIndex);
+  if (node->is_strict()) {
+    operand.Unuse();
+    destination()->Split(equal);
+  } else {
+    // The 'null' value is only equal to 'undefined' if using non-strict
+    // comparisons.
+    destination()->true_target()->Branch(equal);
+    __ CompareRoot(operand.reg(), Heap::kUndefinedValueRootIndex);
+    destination()->true_target()->Branch(equal);
+    Condition is_smi = masm_->CheckSmi(operand.reg());
+    destination()->false_target()->Branch(is_smi);
+
+    // It can be an undetectable object.
+    // Use a scratch register in preference to spilling operand.reg().
+    Result temp = allocator()->Allocate();
+    ASSERT(temp.is_valid());
+    __ movq(temp.reg(),
+            FieldOperand(operand.reg(), HeapObject::kMapOffset));
+    __ testb(FieldOperand(temp.reg(), Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    temp.Unuse();
+    operand.Unuse();
+    destination()->Split(not_zero);
+  }
+}
+
+
 #ifdef DEBUG
 bool CodeGenerator::HasValidEntryRegisters() {
   return (allocator()->count(rax) == (frame()->is_used(rax) ? 1 : 0))
@@ -8419,15 +8483,10 @@ Result CodeGenerator::EmitKeyedLoad() {
     // Check that the key is a non-negative smi.
     __ JumpIfNotPositiveSmi(key.reg(), deferred->entry_label());
 
-    // Get the elements array from the receiver and check that it
-    // is not a dictionary.
+    // Get the elements array from the receiver.
     __ movq(elements.reg(),
             FieldOperand(receiver.reg(), JSObject::kElementsOffset));
-    if (FLAG_debug_code) {
-      __ Cmp(FieldOperand(elements.reg(), HeapObject::kMapOffset),
-             Factory::fixed_array_map());
-      __ Assert(equal, "JSObject with fast elements map has slow elements");
-    }
+    __ AssertFastElements(elements.reg());
 
     // Check that key is within bounds.
     __ SmiCompare(key.reg(),
@@ -8730,3921 +8789,17 @@ void Reference::SetValue(InitState init_state) {
 }
 
 
-void FastNewClosureStub::Generate(MacroAssembler* masm) {
-  // Create a new closure from the given function info in new
-  // space. Set the context to the current context in rsi.
-  Label gc;
-  __ AllocateInNewSpace(JSFunction::kSize, rax, rbx, rcx, &gc, TAG_OBJECT);
-
-  // Get the function info from the stack.
-  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
-
-  // Compute the function map in the current global context and set that
-  // as the map of the allocated object.
-  __ movq(rcx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-  __ movq(rcx, FieldOperand(rcx, GlobalObject::kGlobalContextOffset));
-  __ movq(rcx, Operand(rcx, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
-  __ movq(FieldOperand(rax, JSObject::kMapOffset), rcx);
-
-  // Initialize the rest of the function. We don't have to update the
-  // write barrier because the allocated object is in new space.
-  __ LoadRoot(rbx, Heap::kEmptyFixedArrayRootIndex);
-  __ LoadRoot(rcx, Heap::kTheHoleValueRootIndex);
-  __ movq(FieldOperand(rax, JSObject::kPropertiesOffset), rbx);
-  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rbx);
-  __ movq(FieldOperand(rax, JSFunction::kPrototypeOrInitialMapOffset), rcx);
-  __ movq(FieldOperand(rax, JSFunction::kSharedFunctionInfoOffset), rdx);
-  __ movq(FieldOperand(rax, JSFunction::kContextOffset), rsi);
-  __ movq(FieldOperand(rax, JSFunction::kLiteralsOffset), rbx);
-
-  // Initialize the code pointer in the function to be the one
-  // found in the shared function info object.
-  __ movq(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset));
-  __ movq(FieldOperand(rax, JSFunction::kCodeOffset), rdx);
-
-
-  // Return and remove the on-stack parameter.
-  __ ret(1 * kPointerSize);
-
-  // Create a new closure through the slower runtime call.
-  __ bind(&gc);
-  __ pop(rcx);  // Temporarily remove return address.
-  __ pop(rdx);
-  __ push(rsi);
-  __ push(rdx);
-  __ push(rcx);  // Restore return address.
-  __ TailCallRuntime(Runtime::kNewClosure, 2, 1);
-}
-
-
-void FastNewContextStub::Generate(MacroAssembler* masm) {
-  // Try to allocate the context in new space.
-  Label gc;
-  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
-  __ AllocateInNewSpace((length * kPointerSize) + FixedArray::kHeaderSize,
-                        rax, rbx, rcx, &gc, TAG_OBJECT);
-
-  // Get the function from the stack.
-  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
-
-  // Setup the object header.
-  __ LoadRoot(kScratchRegister, Heap::kContextMapRootIndex);
-  __ movq(FieldOperand(rax, HeapObject::kMapOffset), kScratchRegister);
-  __ Move(FieldOperand(rax, FixedArray::kLengthOffset), Smi::FromInt(length));
-
-  // Setup the fixed slots.
-  __ xor_(rbx, rbx);  // Set to NULL.
-  __ movq(Operand(rax, Context::SlotOffset(Context::CLOSURE_INDEX)), rcx);
-  __ movq(Operand(rax, Context::SlotOffset(Context::FCONTEXT_INDEX)), rax);
-  __ movq(Operand(rax, Context::SlotOffset(Context::PREVIOUS_INDEX)), rbx);
-  __ movq(Operand(rax, Context::SlotOffset(Context::EXTENSION_INDEX)), rbx);
-
-  // Copy the global object from the surrounding context.
-  __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-  __ movq(Operand(rax, Context::SlotOffset(Context::GLOBAL_INDEX)), rbx);
-
-  // Initialize the rest of the slots to undefined.
-  __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
-  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
-    __ movq(Operand(rax, Context::SlotOffset(i)), rbx);
-  }
-
-  // Return and remove the on-stack parameter.
-  __ movq(rsi, rax);
-  __ ret(1 * kPointerSize);
-
-  // Need to collect. Call into runtime system.
-  __ bind(&gc);
-  __ TailCallRuntime(Runtime::kNewContext, 1, 1);
-}
-
-
-void FastCloneShallowArrayStub::Generate(MacroAssembler* masm) {
-  // Stack layout on entry:
-  //
-  // [rsp + kPointerSize]: constant elements.
-  // [rsp + (2 * kPointerSize)]: literal index.
-  // [rsp + (3 * kPointerSize)]: literals array.
-
-  // All sizes here are multiples of kPointerSize.
-  int elements_size = (length_ > 0) ? FixedArray::SizeFor(length_) : 0;
-  int size = JSArray::kSize + elements_size;
-
-  // Load boilerplate object into rcx and check if we need to create a
-  // boilerplate.
-  Label slow_case;
-  __ movq(rcx, Operand(rsp, 3 * kPointerSize));
-  __ movq(rax, Operand(rsp, 2 * kPointerSize));
-  SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
-  __ movq(rcx,
-          FieldOperand(rcx, index.reg, index.scale, FixedArray::kHeaderSize));
-  __ CompareRoot(rcx, Heap::kUndefinedValueRootIndex);
-  __ j(equal, &slow_case);
-
-  // Allocate both the JS array and the elements array in one big
-  // allocation. This avoids multiple limit checks.
-  __ AllocateInNewSpace(size, rax, rbx, rdx, &slow_case, TAG_OBJECT);
-
-  // Copy the JS array part.
-  for (int i = 0; i < JSArray::kSize; i += kPointerSize) {
-    if ((i != JSArray::kElementsOffset) || (length_ == 0)) {
-      __ movq(rbx, FieldOperand(rcx, i));
-      __ movq(FieldOperand(rax, i), rbx);
-    }
-  }
-
-  if (length_ > 0) {
-    // Get hold of the elements array of the boilerplate and setup the
-    // elements pointer in the resulting object.
-    __ movq(rcx, FieldOperand(rcx, JSArray::kElementsOffset));
-    __ lea(rdx, Operand(rax, JSArray::kSize));
-    __ movq(FieldOperand(rax, JSArray::kElementsOffset), rdx);
-
-    // Copy the elements array.
-    for (int i = 0; i < elements_size; i += kPointerSize) {
-      __ movq(rbx, FieldOperand(rcx, i));
-      __ movq(FieldOperand(rdx, i), rbx);
-    }
-  }
-
-  // Return and remove the on-stack parameters.
-  __ ret(3 * kPointerSize);
-
-  __ bind(&slow_case);
-  __ TailCallRuntime(Runtime::kCreateArrayLiteralShallow, 3, 1);
-}
-
-
-void ToBooleanStub::Generate(MacroAssembler* masm) {
-  Label false_result, true_result, not_string;
-  __ movq(rax, Operand(rsp, 1 * kPointerSize));
-
-  // 'null' => false.
-  __ CompareRoot(rax, Heap::kNullValueRootIndex);
-  __ j(equal, &false_result);
-
-  // Get the map and type of the heap object.
-  // We don't use CmpObjectType because we manipulate the type field.
-  __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
-  __ movzxbq(rcx, FieldOperand(rdx, Map::kInstanceTypeOffset));
-
-  // Undetectable => false.
-  __ movzxbq(rbx, FieldOperand(rdx, Map::kBitFieldOffset));
-  __ and_(rbx, Immediate(1 << Map::kIsUndetectable));
-  __ j(not_zero, &false_result);
-
-  // JavaScript object => true.
-  __ cmpq(rcx, Immediate(FIRST_JS_OBJECT_TYPE));
-  __ j(above_equal, &true_result);
-
-  // String value => false iff empty.
-  __ cmpq(rcx, Immediate(FIRST_NONSTRING_TYPE));
-  __ j(above_equal, &not_string);
-  __ movq(rdx, FieldOperand(rax, String::kLengthOffset));
-  __ SmiTest(rdx);
-  __ j(zero, &false_result);
-  __ jmp(&true_result);
-
-  __ bind(&not_string);
-  __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
-  __ j(not_equal, &true_result);
-  // HeapNumber => false iff +0, -0, or NaN.
-  // These three cases set the zero flag when compared to zero using ucomisd.
-  __ xorpd(xmm0, xmm0);
-  __ ucomisd(xmm0, FieldOperand(rax, HeapNumber::kValueOffset));
-  __ j(zero, &false_result);
-  // Fall through to |true_result|.
-
-  // Return 1/0 for true/false in rax.
-  __ bind(&true_result);
-  __ movq(rax, Immediate(1));
-  __ ret(1 * kPointerSize);
-  __ bind(&false_result);
-  __ xor_(rax, rax);
-  __ ret(1 * kPointerSize);
-}
-
-
-void GenericBinaryOpStub::GenerateCall(
-    MacroAssembler* masm,
-    Register left,
-    Register right) {
-  if (!ArgsInRegistersSupported()) {
-    // Pass arguments on the stack.
-    __ push(left);
-    __ push(right);
-  } else {
-    // The calling convention with registers is left in rdx and right in rax.
-    Register left_arg = rdx;
-    Register right_arg = rax;
-    if (!(left.is(left_arg) && right.is(right_arg))) {
-      if (left.is(right_arg) && right.is(left_arg)) {
-        if (IsOperationCommutative()) {
-          SetArgsReversed();
-        } else {
-          __ xchg(left, right);
-        }
-      } else if (left.is(left_arg)) {
-        __ movq(right_arg, right);
-      } else if (right.is(right_arg)) {
-        __ movq(left_arg, left);
-      } else if (left.is(right_arg)) {
-        if (IsOperationCommutative()) {
-          __ movq(left_arg, right);
-          SetArgsReversed();
-        } else {
-          // Order of moves important to avoid destroying left argument.
-          __ movq(left_arg, left);
-          __ movq(right_arg, right);
-        }
-      } else if (right.is(left_arg)) {
-        if (IsOperationCommutative()) {
-          __ movq(right_arg, left);
-          SetArgsReversed();
-        } else {
-          // Order of moves important to avoid destroying right argument.
-          __ movq(right_arg, right);
-          __ movq(left_arg, left);
-        }
-      } else {
-        // Order of moves is not important.
-        __ movq(left_arg, left);
-        __ movq(right_arg, right);
-      }
-    }
-
-    // Update flags to indicate that arguments are in registers.
-    SetArgsInRegisters();
-    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
-  }
-
-  // Call the stub.
-  __ CallStub(this);
-}
-
-
-void GenericBinaryOpStub::GenerateCall(
-    MacroAssembler* masm,
-    Register left,
-    Smi* right) {
-  if (!ArgsInRegistersSupported()) {
-    // Pass arguments on the stack.
-    __ push(left);
-    __ Push(right);
-  } else {
-    // The calling convention with registers is left in rdx and right in rax.
-    Register left_arg = rdx;
-    Register right_arg = rax;
-    if (left.is(left_arg)) {
-      __ Move(right_arg, right);
-    } else if (left.is(right_arg) && IsOperationCommutative()) {
-      __ Move(left_arg, right);
-      SetArgsReversed();
-    } else {
-      // For non-commutative operations, left and right_arg might be
-      // the same register.  Therefore, the order of the moves is
-      // important here in order to not overwrite left before moving
-      // it to left_arg.
-      __ movq(left_arg, left);
-      __ Move(right_arg, right);
-    }
-
-    // Update flags to indicate that arguments are in registers.
-    SetArgsInRegisters();
-    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
-  }
-
-  // Call the stub.
-  __ CallStub(this);
-}
-
-
-void GenericBinaryOpStub::GenerateCall(
-    MacroAssembler* masm,
-    Smi* left,
-    Register right) {
-  if (!ArgsInRegistersSupported()) {
-    // Pass arguments on the stack.
-    __ Push(left);
-    __ push(right);
-  } else {
-    // The calling convention with registers is left in rdx and right in rax.
-    Register left_arg = rdx;
-    Register right_arg = rax;
-    if (right.is(right_arg)) {
-      __ Move(left_arg, left);
-    } else if (right.is(left_arg) && IsOperationCommutative()) {
-      __ Move(right_arg, left);
-      SetArgsReversed();
-    } else {
-      // For non-commutative operations, right and left_arg might be
-      // the same register.  Therefore, the order of the moves is
-      // important here in order to not overwrite right before moving
-      // it to right_arg.
-      __ movq(right_arg, right);
-      __ Move(left_arg, left);
-    }
-    // Update flags to indicate that arguments are in registers.
-    SetArgsInRegisters();
-    __ IncrementCounter(&Counters::generic_binary_stub_calls_regs, 1);
-  }
-
-  // Call the stub.
-  __ CallStub(this);
-}
-
-
-Result GenericBinaryOpStub::GenerateCall(MacroAssembler* masm,
-                                         VirtualFrame* frame,
-                                         Result* left,
-                                         Result* right) {
-  if (ArgsInRegistersSupported()) {
-    SetArgsInRegisters();
-    return frame->CallStub(this, left, right);
-  } else {
-    frame->Push(left);
-    frame->Push(right);
-    return frame->CallStub(this, 2);
-  }
-}
-
-
-void GenericBinaryOpStub::GenerateSmiCode(MacroAssembler* masm, Label* slow) {
-  // 1. Move arguments into rdx, rax except for DIV and MOD, which need the
-  // dividend in rax and rdx free for the division.  Use rax, rbx for those.
-  Comment load_comment(masm, "-- Load arguments");
-  Register left = rdx;
-  Register right = rax;
-  if (op_ == Token::DIV || op_ == Token::MOD) {
-    left = rax;
-    right = rbx;
-    if (HasArgsInRegisters()) {
-      __ movq(rbx, rax);
-      __ movq(rax, rdx);
-    }
-  }
-  if (!HasArgsInRegisters()) {
-    __ movq(right, Operand(rsp, 1 * kPointerSize));
-    __ movq(left, Operand(rsp, 2 * kPointerSize));
-  }
-
-  Label not_smis;
-  // 2. Smi check both operands.
-  if (static_operands_type_.IsSmi()) {
-    // Skip smi check if we know that both arguments are smis.
-    if (FLAG_debug_code) {
-      __ AbortIfNotSmi(left);
-      __ AbortIfNotSmi(right);
-    }
-    if (op_ == Token::BIT_OR) {
-      // Handle OR here, since we do extra smi-checking in the or code below.
-      __ SmiOr(right, right, left);
-      GenerateReturn(masm);
-      return;
-    }
+Result CodeGenerator::GenerateGenericBinaryOpStubCall(GenericBinaryOpStub* stub,
+                                                      Result* left,
+                                                      Result* right) {
+  if (stub->ArgsInRegistersSupported()) {
+    stub->SetArgsInRegisters();
+    return frame_->CallStub(stub, left, right);
   } else {
-    if (op_ != Token::BIT_OR) {
-      // Skip the check for OR as it is better combined with the
-      // actual operation.
-      Comment smi_check_comment(masm, "-- Smi check arguments");
-      __ JumpIfNotBothSmi(left, right, &not_smis);
-    }
-  }
-
-  // 3. Operands are both smis (except for OR), perform the operation leaving
-  // the result in rax and check the result if necessary.
-  Comment perform_smi(masm, "-- Perform smi operation");
-  Label use_fp_on_smis;
-  switch (op_) {
-    case Token::ADD: {
-      ASSERT(right.is(rax));
-      __ SmiAdd(right, right, left, &use_fp_on_smis);  // ADD is commutative.
-      break;
-    }
-
-    case Token::SUB: {
-      __ SmiSub(left, left, right, &use_fp_on_smis);
-      __ movq(rax, left);
-      break;
-    }
-
-    case Token::MUL:
-      ASSERT(right.is(rax));
-      __ SmiMul(right, right, left, &use_fp_on_smis);  // MUL is commutative.
-      break;
-
-    case Token::DIV:
-      ASSERT(left.is(rax));
-      __ SmiDiv(left, left, right, &use_fp_on_smis);
-      break;
-
-    case Token::MOD:
-      ASSERT(left.is(rax));
-      __ SmiMod(left, left, right, slow);
-      break;
-
-    case Token::BIT_OR:
-      ASSERT(right.is(rax));
-      __ movq(rcx, right);  // Save the right operand.
-      __ SmiOr(right, right, left);  // BIT_OR is commutative.
-      __ testb(right, Immediate(kSmiTagMask));
-      __ j(not_zero, &not_smis);
-      break;
-
-    case Token::BIT_AND:
-      ASSERT(right.is(rax));
-      __ SmiAnd(right, right, left);  // BIT_AND is commutative.
-      break;
-
-    case Token::BIT_XOR:
-      ASSERT(right.is(rax));
-      __ SmiXor(right, right, left);  // BIT_XOR is commutative.
-      break;
-
-    case Token::SHL:
-    case Token::SHR:
-    case Token::SAR:
-      switch (op_) {
-        case Token::SAR:
-          __ SmiShiftArithmeticRight(left, left, right);
-          break;
-        case Token::SHR:
-          __ SmiShiftLogicalRight(left, left, right, slow);
-          break;
-        case Token::SHL:
-          __ SmiShiftLeft(left, left, right);
-          break;
-        default:
-          UNREACHABLE();
-      }
-      __ movq(rax, left);
-      break;
-
-    default:
-      UNREACHABLE();
-      break;
-  }
-
-  // 4. Emit return of result in rax.
-  GenerateReturn(masm);
-
-  // 5. For some operations emit inline code to perform floating point
-  // operations on known smis (e.g., if the result of the operation
-  // overflowed the smi range).
-  switch (op_) {
-    case Token::ADD:
-    case Token::SUB:
-    case Token::MUL:
-    case Token::DIV: {
-      ASSERT(use_fp_on_smis.is_linked());
-      __ bind(&use_fp_on_smis);
-      if (op_ == Token::DIV) {
-        __ movq(rdx, rax);
-        __ movq(rax, rbx);
-      }
-      // left is rdx, right is rax.
-      __ AllocateHeapNumber(rbx, rcx, slow);
-      FloatingPointHelper::LoadSSE2SmiOperands(masm);
-      switch (op_) {
-        case Token::ADD: __ addsd(xmm0, xmm1); break;
-        case Token::SUB: __ subsd(xmm0, xmm1); break;
-        case Token::MUL: __ mulsd(xmm0, xmm1); break;
-        case Token::DIV: __ divsd(xmm0, xmm1); break;
-        default: UNREACHABLE();
-      }
-      __ movsd(FieldOperand(rbx, HeapNumber::kValueOffset), xmm0);
-      __ movq(rax, rbx);
-      GenerateReturn(masm);
-    }
-    default:
-      break;
-  }
-
-  // 6. Non-smi operands, fall out to the non-smi code with the operands in
-  // rdx and rax.
-  Comment done_comment(masm, "-- Enter non-smi code");
-  __ bind(&not_smis);
-
-  switch (op_) {
-    case Token::DIV:
-    case Token::MOD:
-      // Operands are in rax, rbx at this point.
-      __ movq(rdx, rax);
-      __ movq(rax, rbx);
-      break;
-
-    case Token::BIT_OR:
-      // Right operand is saved in rcx and rax was destroyed by the smi
-      // operation.
-      __ movq(rax, rcx);
-      break;
-
-    default:
-      break;
-  }
-}
-
-
-void GenericBinaryOpStub::Generate(MacroAssembler* masm) {
-  Label call_runtime;
-
-  if (ShouldGenerateSmiCode()) {
-    GenerateSmiCode(masm, &call_runtime);
-  } else if (op_ != Token::MOD) {
-    if (!HasArgsInRegisters()) {
-      GenerateLoadArguments(masm);
-    }
-  }
-  // Floating point case.
-  if (ShouldGenerateFPCode()) {
-    switch (op_) {
-      case Token::ADD:
-      case Token::SUB:
-      case Token::MUL:
-      case Token::DIV: {
-        if (runtime_operands_type_ == BinaryOpIC::DEFAULT &&
-            HasSmiCodeInStub()) {
-          // Execution reaches this point when the first non-smi argument occurs
-          // (and only if smi code is generated). This is the right moment to
-          // patch to HEAP_NUMBERS state. The transition is attempted only for
-          // the four basic operations. The stub stays in the DEFAULT state
-          // forever for all other operations (also if smi code is skipped).
-          GenerateTypeTransition(masm);
-          break;
-        }
-
-        Label not_floats;
-        // rax: y
-        // rdx: x
-        if (static_operands_type_.IsNumber()) {
-          if (FLAG_debug_code) {
-            // Assert at runtime that inputs are only numbers.
-            __ AbortIfNotNumber(rdx);
-            __ AbortIfNotNumber(rax);
-          }
-          FloatingPointHelper::LoadSSE2NumberOperands(masm);
-        } else {
-          FloatingPointHelper::LoadSSE2UnknownOperands(masm, &call_runtime);
-        }
-
-        switch (op_) {
-          case Token::ADD: __ addsd(xmm0, xmm1); break;
-          case Token::SUB: __ subsd(xmm0, xmm1); break;
-          case Token::MUL: __ mulsd(xmm0, xmm1); break;
-          case Token::DIV: __ divsd(xmm0, xmm1); break;
-          default: UNREACHABLE();
-        }
-        // Allocate a heap number, if needed.
-        Label skip_allocation;
-        OverwriteMode mode = mode_;
-        if (HasArgsReversed()) {
-          if (mode == OVERWRITE_RIGHT) {
-            mode = OVERWRITE_LEFT;
-          } else if (mode == OVERWRITE_LEFT) {
-            mode = OVERWRITE_RIGHT;
-          }
-        }
-        switch (mode) {
-          case OVERWRITE_LEFT:
-            __ JumpIfNotSmi(rdx, &skip_allocation);
-            __ AllocateHeapNumber(rbx, rcx, &call_runtime);
-            __ movq(rdx, rbx);
-            __ bind(&skip_allocation);
-            __ movq(rax, rdx);
-            break;
-          case OVERWRITE_RIGHT:
-            // If the argument in rax is already an object, we skip the
-            // allocation of a heap number.
-            __ JumpIfNotSmi(rax, &skip_allocation);
-            // Fall through!
-          case NO_OVERWRITE:
-            // Allocate a heap number for the result. Keep rax and rdx intact
-            // for the possible runtime call.
-            __ AllocateHeapNumber(rbx, rcx, &call_runtime);
-            __ movq(rax, rbx);
-            __ bind(&skip_allocation);
-            break;
-          default: UNREACHABLE();
-        }
-        __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), xmm0);
-        GenerateReturn(masm);
-        __ bind(&not_floats);
-        if (runtime_operands_type_ == BinaryOpIC::DEFAULT &&
-            !HasSmiCodeInStub()) {
-            // Execution reaches this point when the first non-number argument
-            // occurs (and only if smi code is skipped from the stub, otherwise
-            // the patching has already been done earlier in this case branch).
-            // A perfect moment to try patching to STRINGS for ADD operation.
-            if (op_ == Token::ADD) {
-              GenerateTypeTransition(masm);
-            }
-        }
-        break;
-      }
-      case Token::MOD: {
-        // For MOD we go directly to runtime in the non-smi case.
-        break;
-      }
-      case Token::BIT_OR:
-      case Token::BIT_AND:
-      case Token::BIT_XOR:
-      case Token::SAR:
-      case Token::SHL:
-      case Token::SHR: {
-        Label skip_allocation, non_smi_shr_result;
-        Register heap_number_map = r9;
-        __ LoadRoot(heap_number_map, Heap::kHeapNumberMapRootIndex);
-        if (static_operands_type_.IsNumber()) {
-          if (FLAG_debug_code) {
-            // Assert at runtime that inputs are only numbers.
-            __ AbortIfNotNumber(rdx);
-            __ AbortIfNotNumber(rax);
-          }
-          FloatingPointHelper::LoadNumbersAsIntegers(masm);
-        } else {
-          FloatingPointHelper::LoadAsIntegers(masm,
-                                              &call_runtime,
-                                              heap_number_map);
-        }
-        switch (op_) {
-          case Token::BIT_OR:  __ orl(rax, rcx); break;
-          case Token::BIT_AND: __ andl(rax, rcx); break;
-          case Token::BIT_XOR: __ xorl(rax, rcx); break;
-          case Token::SAR: __ sarl_cl(rax); break;
-          case Token::SHL: __ shll_cl(rax); break;
-          case Token::SHR: {
-            __ shrl_cl(rax);
-            // Check if result is negative. This can only happen for a shift
-            // by zero.
-            __ testl(rax, rax);
-            __ j(negative, &non_smi_shr_result);
-            break;
-          }
-          default: UNREACHABLE();
-        }
-
-        STATIC_ASSERT(kSmiValueSize == 32);
-        // Tag smi result and return.
-        __ Integer32ToSmi(rax, rax);
-        GenerateReturn(masm);
-
-        // All bit-ops except SHR return a signed int32 that can be
-        // returned immediately as a smi.
-        // We might need to allocate a HeapNumber if we shift a negative
-        // number right by zero (i.e., convert to UInt32).
-        if (op_ == Token::SHR) {
-          ASSERT(non_smi_shr_result.is_linked());
-          __ bind(&non_smi_shr_result);
-          // Allocate a heap number if needed.
-          __ movl(rbx, rax);  // rbx holds result value (uint32 value as int64).
-          switch (mode_) {
-            case OVERWRITE_LEFT:
-            case OVERWRITE_RIGHT:
-              // If the operand was an object, we skip the
-              // allocation of a heap number.
-              __ movq(rax, Operand(rsp, mode_ == OVERWRITE_RIGHT ?
-                                   1 * kPointerSize : 2 * kPointerSize));
-              __ JumpIfNotSmi(rax, &skip_allocation);
-              // Fall through!
-            case NO_OVERWRITE:
-              // Allocate heap number in new space.
-              // Not using AllocateHeapNumber macro in order to reuse
-              // already loaded heap_number_map.
-              __ AllocateInNewSpace(HeapNumber::kSize,
-                                    rax,
-                                    rcx,
-                                    no_reg,
-                                    &call_runtime,
-                                    TAG_OBJECT);
-              // Set the map.
-              if (FLAG_debug_code) {
-                __ AbortIfNotRootValue(heap_number_map,
-                                       Heap::kHeapNumberMapRootIndex,
-                                       "HeapNumberMap register clobbered.");
-              }
-              __ movq(FieldOperand(rax, HeapObject::kMapOffset),
-                      heap_number_map);
-              __ bind(&skip_allocation);
-              break;
-            default: UNREACHABLE();
-          }
-          // Store the result in the HeapNumber and return.
-          __ cvtqsi2sd(xmm0, rbx);
-          __ movsd(FieldOperand(rax, HeapNumber::kValueOffset), xmm0);
-          GenerateReturn(masm);
-        }
-
-        break;
-      }
-      default: UNREACHABLE(); break;
-    }
-  }
-
-  // If all else fails, use the runtime system to get the correct
-  // result. If arguments was passed in registers now place them on the
-  // stack in the correct order below the return address.
-  __ bind(&call_runtime);
-
-  if (HasArgsInRegisters()) {
-    GenerateRegisterArgsPush(masm);
-  }
-
-  switch (op_) {
-    case Token::ADD: {
-      // Registers containing left and right operands respectively.
-      Register lhs, rhs;
-
-      if (HasArgsReversed()) {
-        lhs = rax;
-        rhs = rdx;
-      } else {
-        lhs = rdx;
-        rhs = rax;
-      }
-
-      // Test for string arguments before calling runtime.
-      Label not_strings, both_strings, not_string1, string1, string1_smi2;
-
-      // If this stub has already generated FP-specific code then the arguments
-      // are already in rdx and rax.
-      if (!ShouldGenerateFPCode() && !HasArgsInRegisters()) {
-        GenerateLoadArguments(masm);
-      }
-
-      Condition is_smi;
-      is_smi = masm->CheckSmi(lhs);
-      __ j(is_smi, &not_string1);
-      __ CmpObjectType(lhs, FIRST_NONSTRING_TYPE, r8);
-      __ j(above_equal, &not_string1);
-
-      // First argument is a a string, test second.
-      is_smi = masm->CheckSmi(rhs);
-      __ j(is_smi, &string1_smi2);
-      __ CmpObjectType(rhs, FIRST_NONSTRING_TYPE, r9);
-      __ j(above_equal, &string1);
-
-      // First and second argument are strings.
-      StringAddStub string_add_stub(NO_STRING_CHECK_IN_STUB);
-      __ TailCallStub(&string_add_stub);
-
-      __ bind(&string1_smi2);
-      // First argument is a string, second is a smi. Try to lookup the number
-      // string for the smi in the number string cache.
-      NumberToStringStub::GenerateLookupNumberStringCache(
-          masm, rhs, rbx, rcx, r8, true, &string1);
-
-      // Replace second argument on stack and tailcall string add stub to make
-      // the result.
-      __ movq(Operand(rsp, 1 * kPointerSize), rbx);
-      __ TailCallStub(&string_add_stub);
-
-      // Only first argument is a string.
-      __ bind(&string1);
-      __ InvokeBuiltin(Builtins::STRING_ADD_LEFT, JUMP_FUNCTION);
-
-      // First argument was not a string, test second.
-      __ bind(&not_string1);
-      is_smi = masm->CheckSmi(rhs);
-      __ j(is_smi, &not_strings);
-      __ CmpObjectType(rhs, FIRST_NONSTRING_TYPE, rhs);
-      __ j(above_equal, &not_strings);
-
-      // Only second argument is a string.
-      __ InvokeBuiltin(Builtins::STRING_ADD_RIGHT, JUMP_FUNCTION);
-
-      __ bind(&not_strings);
-      // Neither argument is a string.
-      __ InvokeBuiltin(Builtins::ADD, JUMP_FUNCTION);
-      break;
-    }
-    case Token::SUB:
-      __ InvokeBuiltin(Builtins::SUB, JUMP_FUNCTION);
-      break;
-    case Token::MUL:
-      __ InvokeBuiltin(Builtins::MUL, JUMP_FUNCTION);
-      break;
-    case Token::DIV:
-      __ InvokeBuiltin(Builtins::DIV, JUMP_FUNCTION);
-      break;
-    case Token::MOD:
-      __ InvokeBuiltin(Builtins::MOD, JUMP_FUNCTION);
-      break;
-    case Token::BIT_OR:
-      __ InvokeBuiltin(Builtins::BIT_OR, JUMP_FUNCTION);
-      break;
-    case Token::BIT_AND:
-      __ InvokeBuiltin(Builtins::BIT_AND, JUMP_FUNCTION);
-      break;
-    case Token::BIT_XOR:
-      __ InvokeBuiltin(Builtins::BIT_XOR, JUMP_FUNCTION);
-      break;
-    case Token::SAR:
-      __ InvokeBuiltin(Builtins::SAR, JUMP_FUNCTION);
-      break;
-    case Token::SHL:
-      __ InvokeBuiltin(Builtins::SHL, JUMP_FUNCTION);
-      break;
-    case Token::SHR:
-      __ InvokeBuiltin(Builtins::SHR, JUMP_FUNCTION);
-      break;
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-void GenericBinaryOpStub::GenerateLoadArguments(MacroAssembler* masm) {
-  ASSERT(!HasArgsInRegisters());
-  __ movq(rax, Operand(rsp, 1 * kPointerSize));
-  __ movq(rdx, Operand(rsp, 2 * kPointerSize));
-}
-
-
-void GenericBinaryOpStub::GenerateReturn(MacroAssembler* masm) {
-  // If arguments are not passed in registers remove them from the stack before
-  // returning.
-  if (!HasArgsInRegisters()) {
-    __ ret(2 * kPointerSize);  // Remove both operands
-  } else {
-    __ ret(0);
-  }
-}
-
-
-void GenericBinaryOpStub::GenerateRegisterArgsPush(MacroAssembler* masm) {
-  ASSERT(HasArgsInRegisters());
-  __ pop(rcx);
-  if (HasArgsReversed()) {
-    __ push(rax);
-    __ push(rdx);
-  } else {
-    __ push(rdx);
-    __ push(rax);
-  }
-  __ push(rcx);
-}
-
-
-void GenericBinaryOpStub::GenerateTypeTransition(MacroAssembler* masm) {
-  Label get_result;
-
-  // Ensure the operands are on the stack.
-  if (HasArgsInRegisters()) {
-    GenerateRegisterArgsPush(masm);
-  }
-
-  // Left and right arguments are already on stack.
-  __ pop(rcx);  // Save the return address.
-
-  // Push this stub's key.
-  __ Push(Smi::FromInt(MinorKey()));
-
-  // Although the operation and the type info are encoded into the key,
-  // the encoding is opaque, so push them too.
-  __ Push(Smi::FromInt(op_));
-
-  __ Push(Smi::FromInt(runtime_operands_type_));
-
-  __ push(rcx);  // The return address.
-
-  // Perform patching to an appropriate fast case and return the result.
-  __ TailCallExternalReference(
-      ExternalReference(IC_Utility(IC::kBinaryOp_Patch)),
-      5,
-      1);
-}
-
-
-Handle<Code> GetBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info) {
-  GenericBinaryOpStub stub(key, type_info);
-  return stub.GetCode();
-}
-
-
-void TranscendentalCacheStub::Generate(MacroAssembler* masm) {
-  // Input on stack:
-  // rsp[8]: argument (should be number).
-  // rsp[0]: return address.
-  Label runtime_call;
-  Label runtime_call_clear_stack;
-  Label input_not_smi;
-  Label loaded;
-  // Test that rax is a number.
-  __ movq(rax, Operand(rsp, kPointerSize));
-  __ JumpIfNotSmi(rax, &input_not_smi);
-  // Input is a smi. Untag and load it onto the FPU stack.
-  // Then load the bits of the double into rbx.
-  __ SmiToInteger32(rax, rax);
-  __ subq(rsp, Immediate(kPointerSize));
-  __ cvtlsi2sd(xmm1, rax);
-  __ movsd(Operand(rsp, 0), xmm1);
-  __ movq(rbx, xmm1);
-  __ movq(rdx, xmm1);
-  __ fld_d(Operand(rsp, 0));
-  __ addq(rsp, Immediate(kPointerSize));
-  __ jmp(&loaded);
-
-  __ bind(&input_not_smi);
-  // Check if input is a HeapNumber.
-  __ Move(rbx, Factory::heap_number_map());
-  __ cmpq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
-  __ j(not_equal, &runtime_call);
-  // Input is a HeapNumber. Push it on the FPU stack and load its
-  // bits into rbx.
-  __ fld_d(FieldOperand(rax, HeapNumber::kValueOffset));
-  __ movq(rbx, FieldOperand(rax, HeapNumber::kValueOffset));
-  __ movq(rdx, rbx);
-  __ bind(&loaded);
-  // ST[0] == double value
-  // rbx = bits of double value.
-  // rdx = also bits of double value.
-  // Compute hash (h is 32 bits, bits are 64 and the shifts are arithmetic):
-  //   h = h0 = bits ^ (bits >> 32);
-  //   h ^= h >> 16;
-  //   h ^= h >> 8;
-  //   h = h & (cacheSize - 1);
-  // or h = (h0 ^ (h0 >> 8) ^ (h0 >> 16) ^ (h0 >> 24)) & (cacheSize - 1)
-  __ sar(rdx, Immediate(32));
-  __ xorl(rdx, rbx);
-  __ movl(rcx, rdx);
-  __ movl(rax, rdx);
-  __ movl(rdi, rdx);
-  __ sarl(rdx, Immediate(8));
-  __ sarl(rcx, Immediate(16));
-  __ sarl(rax, Immediate(24));
-  __ xorl(rcx, rdx);
-  __ xorl(rax, rdi);
-  __ xorl(rcx, rax);
-  ASSERT(IsPowerOf2(TranscendentalCache::kCacheSize));
-  __ andl(rcx, Immediate(TranscendentalCache::kCacheSize - 1));
-
-  // ST[0] == double value.
-  // rbx = bits of double value.
-  // rcx = TranscendentalCache::hash(double value).
-  __ movq(rax, ExternalReference::transcendental_cache_array_address());
-  // rax points to cache array.
-  __ movq(rax, Operand(rax, type_ * sizeof(TranscendentalCache::caches_[0])));
-  // rax points to the cache for the type type_.
-  // If NULL, the cache hasn't been initialized yet, so go through runtime.
-  __ testq(rax, rax);
-  __ j(zero, &runtime_call_clear_stack);
-#ifdef DEBUG
-  // Check that the layout of cache elements match expectations.
-  {  // NOLINT - doesn't like a single brace on a line.
-    TranscendentalCache::Element test_elem[2];
-    char* elem_start = reinterpret_cast<char*>(&test_elem[0]);
-    char* elem2_start = reinterpret_cast<char*>(&test_elem[1]);
-    char* elem_in0  = reinterpret_cast<char*>(&(test_elem[0].in[0]));
-    char* elem_in1  = reinterpret_cast<char*>(&(test_elem[0].in[1]));
-    char* elem_out = reinterpret_cast<char*>(&(test_elem[0].output));
-    // Two uint_32's and a pointer per element.
-    CHECK_EQ(16, static_cast<int>(elem2_start - elem_start));
-    CHECK_EQ(0, static_cast<int>(elem_in0 - elem_start));
-    CHECK_EQ(kIntSize, static_cast<int>(elem_in1 - elem_start));
-    CHECK_EQ(2 * kIntSize, static_cast<int>(elem_out - elem_start));
-  }
-#endif
-  // Find the address of the rcx'th entry in the cache, i.e., &rax[rcx*16].
-  __ addl(rcx, rcx);
-  __ lea(rcx, Operand(rax, rcx, times_8, 0));
-  // Check if cache matches: Double value is stored in uint32_t[2] array.
-  Label cache_miss;
-  __ cmpq(rbx, Operand(rcx, 0));
-  __ j(not_equal, &cache_miss);
-  // Cache hit!
-  __ movq(rax, Operand(rcx, 2 * kIntSize));
-  __ fstp(0);  // Clear FPU stack.
-  __ ret(kPointerSize);
-
-  __ bind(&cache_miss);
-  // Update cache with new value.
-  Label nan_result;
-  GenerateOperation(masm, &nan_result);
-  __ AllocateHeapNumber(rax, rdi, &runtime_call_clear_stack);
-  __ movq(Operand(rcx, 0), rbx);
-  __ movq(Operand(rcx, 2 * kIntSize), rax);
-  __ fstp_d(FieldOperand(rax, HeapNumber::kValueOffset));
-  __ ret(kPointerSize);
-
-  __ bind(&runtime_call_clear_stack);
-  __ fstp(0);
-  __ bind(&runtime_call);
-  __ TailCallExternalReference(ExternalReference(RuntimeFunction()), 1, 1);
-
-  __ bind(&nan_result);
-  __ fstp(0);  // Remove argument from FPU stack.
-  __ LoadRoot(rax, Heap::kNanValueRootIndex);
-  __ movq(Operand(rcx, 0), rbx);
-  __ movq(Operand(rcx, 2 * kIntSize), rax);
-  __ ret(kPointerSize);
-}
-
-
-Runtime::FunctionId TranscendentalCacheStub::RuntimeFunction() {
-  switch (type_) {
-    // Add more cases when necessary.
-    case TranscendentalCache::SIN: return Runtime::kMath_sin;
-    case TranscendentalCache::COS: return Runtime::kMath_cos;
-    default:
-      UNIMPLEMENTED();
-      return Runtime::kAbort;
-  }
-}
-
-
-void TranscendentalCacheStub::GenerateOperation(MacroAssembler* masm,
-                                                Label* on_nan_result) {
-  // Registers:
-  // rbx: Bits of input double. Must be preserved.
-  // rcx: Pointer to cache entry. Must be preserved.
-  // st(0): Input double
-  Label done;
-  ASSERT(type_ == TranscendentalCache::SIN ||
-         type_ == TranscendentalCache::COS);
-  // More transcendental types can be added later.
-
-  // Both fsin and fcos require arguments in the range +/-2^63 and
-  // return NaN for infinities and NaN. They can share all code except
-  // the actual fsin/fcos operation.
-  Label in_range;
-  // If argument is outside the range -2^63..2^63, fsin/cos doesn't
-  // work. We must reduce it to the appropriate range.
-  __ movq(rdi, rbx);
-  // Move exponent and sign bits to low bits.
-  __ shr(rdi, Immediate(HeapNumber::kMantissaBits));
-  // Remove sign bit.
-  __ andl(rdi, Immediate((1 << HeapNumber::kExponentBits) - 1));
-  int supported_exponent_limit = (63 + HeapNumber::kExponentBias);
-  __ cmpl(rdi, Immediate(supported_exponent_limit));
-  __ j(below, &in_range);
-  // Check for infinity and NaN. Both return NaN for sin.
-  __ cmpl(rdi, Immediate(0x7ff));
-  __ j(equal, on_nan_result);
-
-  // Use fpmod to restrict argument to the range +/-2*PI.
-  __ fldpi();
-  __ fadd(0);
-  __ fld(1);
-  // FPU Stack: input, 2*pi, input.
-  {
-    Label no_exceptions;
-    __ fwait();
-    __ fnstsw_ax();
-    // Clear if Illegal Operand or Zero Division exceptions are set.
-    __ testl(rax, Immediate(5));  // #IO and #ZD flags of FPU status word.
-    __ j(zero, &no_exceptions);
-    __ fnclex();
-    __ bind(&no_exceptions);
-  }
-
-  // Compute st(0) % st(1)
-  {
-    Label partial_remainder_loop;
-    __ bind(&partial_remainder_loop);
-    __ fprem1();
-    __ fwait();
-    __ fnstsw_ax();
-    __ testl(rax, Immediate(0x400));  // Check C2 bit of FPU status word.
-    // If C2 is set, computation only has partial result. Loop to
-    // continue computation.
-    __ j(not_zero, &partial_remainder_loop);
-  }
-  // FPU Stack: input, 2*pi, input % 2*pi
-  __ fstp(2);
-  // FPU Stack: input % 2*pi, 2*pi,
-  __ fstp(0);
-  // FPU Stack: input % 2*pi
-  __ bind(&in_range);
-  switch (type_) {
-    case TranscendentalCache::SIN:
-      __ fsin();
-      break;
-    case TranscendentalCache::COS:
-      __ fcos();
-      break;
-    default:
-      UNREACHABLE();
-  }
-  __ bind(&done);
-}
-
-
-// Get the integer part of a heap number.
-// Overwrites the contents of rdi, rbx and rcx. Result cannot be rdi or rbx.
-void IntegerConvert(MacroAssembler* masm,
-                    Register result,
-                    Register source) {
-  // Result may be rcx. If result and source are the same register, source will
-  // be overwritten.
-  ASSERT(!result.is(rdi) && !result.is(rbx));
-  // TODO(lrn): When type info reaches here, if value is a 32-bit integer, use
-  // cvttsd2si (32-bit version) directly.
-  Register double_exponent = rbx;
-  Register double_value = rdi;
-  Label done, exponent_63_plus;
-  // Get double and extract exponent.
-  __ movq(double_value, FieldOperand(source, HeapNumber::kValueOffset));
-  // Clear result preemptively, in case we need to return zero.
-  __ xorl(result, result);
-  __ movq(xmm0, double_value);  // Save copy in xmm0 in case we need it there.
-  // Double to remove sign bit, shift exponent down to least significant bits.
-  // and subtract bias to get the unshifted, unbiased exponent.
-  __ lea(double_exponent, Operand(double_value, double_value, times_1, 0));
-  __ shr(double_exponent, Immediate(64 - HeapNumber::kExponentBits));
-  __ subl(double_exponent, Immediate(HeapNumber::kExponentBias));
-  // Check whether the exponent is too big for a 63 bit unsigned integer.
-  __ cmpl(double_exponent, Immediate(63));
-  __ j(above_equal, &exponent_63_plus);
-  // Handle exponent range 0..62.
-  __ cvttsd2siq(result, xmm0);
-  __ jmp(&done);
-
-  __ bind(&exponent_63_plus);
-  // Exponent negative or 63+.
-  __ cmpl(double_exponent, Immediate(83));
-  // If exponent negative or above 83, number contains no significant bits in
-  // the range 0..2^31, so result is zero, and rcx already holds zero.
-  __ j(above, &done);
-
-  // Exponent in rage 63..83.
-  // Mantissa * 2^exponent contains bits in the range 2^0..2^31, namely
-  // the least significant exponent-52 bits.
-
-  // Negate low bits of mantissa if value is negative.
-  __ addq(double_value, double_value);  // Move sign bit to carry.
-  __ sbbl(result, result);  // And convert carry to -1 in result register.
-  // if scratch2 is negative, do (scratch2-1)^-1, otherwise (scratch2-0)^0.
-  __ addl(double_value, result);
-  // Do xor in opposite directions depending on where we want the result
-  // (depending on whether result is rcx or not).
-
-  if (result.is(rcx)) {
-    __ xorl(double_value, result);
-    // Left shift mantissa by (exponent - mantissabits - 1) to save the
-    // bits that have positional values below 2^32 (the extra -1 comes from the
-    // doubling done above to move the sign bit into the carry flag).
-    __ leal(rcx, Operand(double_exponent, -HeapNumber::kMantissaBits - 1));
-    __ shll_cl(double_value);
-    __ movl(result, double_value);
-  } else {
-    // As the then-branch, but move double-value to result before shifting.
-    __ xorl(result, double_value);
-    __ leal(rcx, Operand(double_exponent, -HeapNumber::kMantissaBits - 1));
-    __ shll_cl(result);
-  }
-
-  __ bind(&done);
-}
-
-
-// Input: rdx, rax are the left and right objects of a bit op.
-// Output: rax, rcx are left and right integers for a bit op.
-void FloatingPointHelper::LoadNumbersAsIntegers(MacroAssembler* masm) {
-  // Check float operands.
-  Label done;
-  Label rax_is_smi;
-  Label rax_is_object;
-  Label rdx_is_object;
-
-  __ JumpIfNotSmi(rdx, &rdx_is_object);
-  __ SmiToInteger32(rdx, rdx);
-  __ JumpIfSmi(rax, &rax_is_smi);
-
-  __ bind(&rax_is_object);
-  IntegerConvert(masm, rcx, rax);  // Uses rdi, rcx and rbx.
-  __ jmp(&done);
-
-  __ bind(&rdx_is_object);
-  IntegerConvert(masm, rdx, rdx);  // Uses rdi, rcx and rbx.
-  __ JumpIfNotSmi(rax, &rax_is_object);
-  __ bind(&rax_is_smi);
-  __ SmiToInteger32(rcx, rax);
-
-  __ bind(&done);
-  __ movl(rax, rdx);
-}
-
-
-// Input: rdx, rax are the left and right objects of a bit op.
-// Output: rax, rcx are left and right integers for a bit op.
-void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
-                                         Label* conversion_failure,
-                                         Register heap_number_map) {
-  // Check float operands.
-  Label arg1_is_object, check_undefined_arg1;
-  Label arg2_is_object, check_undefined_arg2;
-  Label load_arg2, done;
-
-  __ JumpIfNotSmi(rdx, &arg1_is_object);
-  __ SmiToInteger32(rdx, rdx);
-  __ jmp(&load_arg2);
-
-  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
-  __ bind(&check_undefined_arg1);
-  __ CompareRoot(rdx, Heap::kUndefinedValueRootIndex);
-  __ j(not_equal, conversion_failure);
-  __ movl(rdx, Immediate(0));
-  __ jmp(&load_arg2);
-
-  __ bind(&arg1_is_object);
-  __ cmpq(FieldOperand(rdx, HeapObject::kMapOffset), heap_number_map);
-  __ j(not_equal, &check_undefined_arg1);
-  // Get the untagged integer version of the edx heap number in rcx.
-  IntegerConvert(masm, rdx, rdx);
-
-  // Here rdx has the untagged integer, rax has a Smi or a heap number.
-  __ bind(&load_arg2);
-  // Test if arg2 is a Smi.
-  __ JumpIfNotSmi(rax, &arg2_is_object);
-  __ SmiToInteger32(rax, rax);
-  __ movl(rcx, rax);
-  __ jmp(&done);
-
-  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
-  __ bind(&check_undefined_arg2);
-  __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
-  __ j(not_equal, conversion_failure);
-  __ movl(rcx, Immediate(0));
-  __ jmp(&done);
-
-  __ bind(&arg2_is_object);
-  __ cmpq(FieldOperand(rax, HeapObject::kMapOffset), heap_number_map);
-  __ j(not_equal, &check_undefined_arg2);
-  // Get the untagged integer version of the rax heap number in rcx.
-  IntegerConvert(masm, rcx, rax);
-  __ bind(&done);
-  __ movl(rax, rdx);
-}
-
-
-void FloatingPointHelper::LoadSSE2SmiOperands(MacroAssembler* masm) {
-  __ SmiToInteger32(kScratchRegister, rdx);
-  __ cvtlsi2sd(xmm0, kScratchRegister);
-  __ SmiToInteger32(kScratchRegister, rax);
-  __ cvtlsi2sd(xmm1, kScratchRegister);
-}
-
-
-void FloatingPointHelper::LoadSSE2NumberOperands(MacroAssembler* masm) {
-  Label load_smi_rdx, load_nonsmi_rax, load_smi_rax, done;
-  // Load operand in rdx into xmm0.
-  __ JumpIfSmi(rdx, &load_smi_rdx);
-  __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
-  // Load operand in rax into xmm1.
-  __ JumpIfSmi(rax, &load_smi_rax);
-  __ bind(&load_nonsmi_rax);
-  __ movsd(xmm1, FieldOperand(rax, HeapNumber::kValueOffset));
-  __ jmp(&done);
-
-  __ bind(&load_smi_rdx);
-  __ SmiToInteger32(kScratchRegister, rdx);
-  __ cvtlsi2sd(xmm0, kScratchRegister);
-  __ JumpIfNotSmi(rax, &load_nonsmi_rax);
-
-  __ bind(&load_smi_rax);
-  __ SmiToInteger32(kScratchRegister, rax);
-  __ cvtlsi2sd(xmm1, kScratchRegister);
-
-  __ bind(&done);
-}
-
-
-void FloatingPointHelper::LoadSSE2UnknownOperands(MacroAssembler* masm,
-                                                  Label* not_numbers) {
-  Label load_smi_rdx, load_nonsmi_rax, load_smi_rax, load_float_rax, done;
-  // Load operand in rdx into xmm0, or branch to not_numbers.
-  __ LoadRoot(rcx, Heap::kHeapNumberMapRootIndex);
-  __ JumpIfSmi(rdx, &load_smi_rdx);
-  __ cmpq(FieldOperand(rdx, HeapObject::kMapOffset), rcx);
-  __ j(not_equal, not_numbers);  // Argument in rdx is not a number.
-  __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
-  // Load operand in rax into xmm1, or branch to not_numbers.
-  __ JumpIfSmi(rax, &load_smi_rax);
-
-  __ bind(&load_nonsmi_rax);
-  __ cmpq(FieldOperand(rax, HeapObject::kMapOffset), rcx);
-  __ j(not_equal, not_numbers);
-  __ movsd(xmm1, FieldOperand(rax, HeapNumber::kValueOffset));
-  __ jmp(&done);
-
-  __ bind(&load_smi_rdx);
-  __ SmiToInteger32(kScratchRegister, rdx);
-  __ cvtlsi2sd(xmm0, kScratchRegister);
-  __ JumpIfNotSmi(rax, &load_nonsmi_rax);
-
-  __ bind(&load_smi_rax);
-  __ SmiToInteger32(kScratchRegister, rax);
-  __ cvtlsi2sd(xmm1, kScratchRegister);
-  __ bind(&done);
-}
-
-
-void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
-  Label slow, done;
-
-  if (op_ == Token::SUB) {
-    // Check whether the value is a smi.
-    Label try_float;
-    __ JumpIfNotSmi(rax, &try_float);
-
-    if (negative_zero_ == kIgnoreNegativeZero) {
-      __ SmiCompare(rax, Smi::FromInt(0));
-      __ j(equal, &done);
-    }
-
-    // Enter runtime system if the value of the smi is zero
-    // to make sure that we switch between 0 and -0.
-    // Also enter it if the value of the smi is Smi::kMinValue.
-    __ SmiNeg(rax, rax, &done);
-
-    // Either zero or Smi::kMinValue, neither of which become a smi when
-    // negated.
-    if (negative_zero_ == kStrictNegativeZero) {
-      __ SmiCompare(rax, Smi::FromInt(0));
-      __ j(not_equal, &slow);
-      __ Move(rax, Factory::minus_zero_value());
-      __ jmp(&done);
-    } else  {
-      __ jmp(&slow);
-    }
-
-    // Try floating point case.
-    __ bind(&try_float);
-    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
-    __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
-    __ j(not_equal, &slow);
-    // Operand is a float, negate its value by flipping sign bit.
-    __ movq(rdx, FieldOperand(rax, HeapNumber::kValueOffset));
-    __ movq(kScratchRegister, Immediate(0x01));
-    __ shl(kScratchRegister, Immediate(63));
-    __ xor_(rdx, kScratchRegister);  // Flip sign.
-    // rdx is value to store.
-    if (overwrite_ == UNARY_OVERWRITE) {
-      __ movq(FieldOperand(rax, HeapNumber::kValueOffset), rdx);
-    } else {
-      __ AllocateHeapNumber(rcx, rbx, &slow);
-      // rcx: allocated 'empty' number
-      __ movq(FieldOperand(rcx, HeapNumber::kValueOffset), rdx);
-      __ movq(rax, rcx);
-    }
-  } else if (op_ == Token::BIT_NOT) {
-    // Check if the operand is a heap number.
-    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
-    __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
-    __ j(not_equal, &slow);
-
-    // Convert the heap number in rax to an untagged integer in rcx.
-    IntegerConvert(masm, rax, rax);
-
-    // Do the bitwise operation and smi tag the result.
-    __ notl(rax);
-    __ Integer32ToSmi(rax, rax);
-  }
-
-  // Return from the stub.
-  __ bind(&done);
-  __ StubReturn(1);
-
-  // Handle the slow case by jumping to the JavaScript builtin.
-  __ bind(&slow);
-  __ pop(rcx);  // pop return address
-  __ push(rax);
-  __ push(rcx);  // push return address
-  switch (op_) {
-    case Token::SUB:
-      __ InvokeBuiltin(Builtins::UNARY_MINUS, JUMP_FUNCTION);
-      break;
-    case Token::BIT_NOT:
-      __ InvokeBuiltin(Builtins::BIT_NOT, JUMP_FUNCTION);
-      break;
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-void ArgumentsAccessStub::GenerateReadElement(MacroAssembler* masm) {
-  // The key is in rdx and the parameter count is in rax.
-
-  // The displacement is used for skipping the frame pointer on the
-  // stack. It is the offset of the last parameter (if any) relative
-  // to the frame pointer.
-  static const int kDisplacement = 1 * kPointerSize;
-
-  // Check that the key is a smi.
-  Label slow;
-  __ JumpIfNotSmi(rdx, &slow);
-
-  // Check if the calling frame is an arguments adaptor frame.
-  Label adaptor;
-  __ movq(rbx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-  __ SmiCompare(Operand(rbx, StandardFrameConstants::kContextOffset),
-                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-  __ j(equal, &adaptor);
-
-  // Check index against formal parameters count limit passed in
-  // through register rax. Use unsigned comparison to get negative
-  // check for free.
-  __ cmpq(rdx, rax);
-  __ j(above_equal, &slow);
-
-  // Read the argument from the stack and return it.
-  SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
-  __ lea(rbx, Operand(rbp, index.reg, index.scale, 0));
-  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
-  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
-  __ Ret();
-
-  // Arguments adaptor case: Check index against actual arguments
-  // limit found in the arguments adaptor frame. Use unsigned
-  // comparison to get negative check for free.
-  __ bind(&adaptor);
-  __ movq(rcx, Operand(rbx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-  __ cmpq(rdx, rcx);
-  __ j(above_equal, &slow);
-
-  // Read the argument from the stack and return it.
-  index = masm->SmiToIndex(rax, rcx, kPointerSizeLog2);
-  __ lea(rbx, Operand(rbx, index.reg, index.scale, 0));
-  index = masm->SmiToNegativeIndex(rdx, rdx, kPointerSizeLog2);
-  __ movq(rax, Operand(rbx, index.reg, index.scale, kDisplacement));
-  __ Ret();
-
-  // Slow-case: Handle non-smi or out-of-bounds access to arguments
-  // by calling the runtime system.
-  __ bind(&slow);
-  __ pop(rbx);  // Return address.
-  __ push(rdx);
-  __ push(rbx);
-  __ TailCallRuntime(Runtime::kGetArgumentsProperty, 1, 1);
-}
-
-
-void ArgumentsAccessStub::GenerateNewObject(MacroAssembler* masm) {
-  // rsp[0] : return address
-  // rsp[8] : number of parameters
-  // rsp[16] : receiver displacement
-  // rsp[24] : function
-
-  // The displacement is used for skipping the return address and the
-  // frame pointer on the stack. It is the offset of the last
-  // parameter (if any) relative to the frame pointer.
-  static const int kDisplacement = 2 * kPointerSize;
-
-  // Check if the calling frame is an arguments adaptor frame.
-  Label adaptor_frame, try_allocate, runtime;
-  __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-  __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
-                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-  __ j(equal, &adaptor_frame);
-
-  // Get the length from the frame.
-  __ SmiToInteger32(rcx, Operand(rsp, 1 * kPointerSize));
-  __ jmp(&try_allocate);
-
-  // Patch the arguments.length and the parameters pointer.
-  __ bind(&adaptor_frame);
-  __ SmiToInteger32(rcx,
-                    Operand(rdx,
-                            ArgumentsAdaptorFrameConstants::kLengthOffset));
-  // Space on stack must already hold a smi.
-  __ Integer32ToSmiField(Operand(rsp, 1 * kPointerSize), rcx);
-  // Do not clobber the length index for the indexing operation since
-  // it is used compute the size for allocation later.
-  __ lea(rdx, Operand(rdx, rcx, times_pointer_size, kDisplacement));
-  __ movq(Operand(rsp, 2 * kPointerSize), rdx);
-
-  // Try the new space allocation. Start out with computing the size of
-  // the arguments object and the elements array.
-  Label add_arguments_object;
-  __ bind(&try_allocate);
-  __ testl(rcx, rcx);
-  __ j(zero, &add_arguments_object);
-  __ leal(rcx, Operand(rcx, times_pointer_size, FixedArray::kHeaderSize));
-  __ bind(&add_arguments_object);
-  __ addl(rcx, Immediate(Heap::kArgumentsObjectSize));
-
-  // Do the allocation of both objects in one go.
-  __ AllocateInNewSpace(rcx, rax, rdx, rbx, &runtime, TAG_OBJECT);
-
-  // Get the arguments boilerplate from the current (global) context.
-  int offset = Context::SlotOffset(Context::ARGUMENTS_BOILERPLATE_INDEX);
-  __ movq(rdi, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
-  __ movq(rdi, FieldOperand(rdi, GlobalObject::kGlobalContextOffset));
-  __ movq(rdi, Operand(rdi, offset));
-
-  // Copy the JS object part.
-  STATIC_ASSERT(JSObject::kHeaderSize == 3 * kPointerSize);
-  __ movq(kScratchRegister, FieldOperand(rdi, 0 * kPointerSize));
-  __ movq(rdx, FieldOperand(rdi, 1 * kPointerSize));
-  __ movq(rbx, FieldOperand(rdi, 2 * kPointerSize));
-  __ movq(FieldOperand(rax, 0 * kPointerSize), kScratchRegister);
-  __ movq(FieldOperand(rax, 1 * kPointerSize), rdx);
-  __ movq(FieldOperand(rax, 2 * kPointerSize), rbx);
-
-  // Setup the callee in-object property.
-  ASSERT(Heap::arguments_callee_index == 0);
-  __ movq(kScratchRegister, Operand(rsp, 3 * kPointerSize));
-  __ movq(FieldOperand(rax, JSObject::kHeaderSize), kScratchRegister);
-
-  // Get the length (smi tagged) and set that as an in-object property too.
-  ASSERT(Heap::arguments_length_index == 1);
-  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
-  __ movq(FieldOperand(rax, JSObject::kHeaderSize + kPointerSize), rcx);
-
-  // If there are no actual arguments, we're done.
-  Label done;
-  __ SmiTest(rcx);
-  __ j(zero, &done);
-
-  // Get the parameters pointer from the stack and untag the length.
-  __ movq(rdx, Operand(rsp, 2 * kPointerSize));
-
-  // Setup the elements pointer in the allocated arguments object and
-  // initialize the header in the elements fixed array.
-  __ lea(rdi, Operand(rax, Heap::kArgumentsObjectSize));
-  __ movq(FieldOperand(rax, JSObject::kElementsOffset), rdi);
-  __ LoadRoot(kScratchRegister, Heap::kFixedArrayMapRootIndex);
-  __ movq(FieldOperand(rdi, FixedArray::kMapOffset), kScratchRegister);
-  __ movq(FieldOperand(rdi, FixedArray::kLengthOffset), rcx);
-  __ SmiToInteger32(rcx, rcx);  // Untag length for the loop below.
-
-  // Copy the fixed array slots.
-  Label loop;
-  __ bind(&loop);
-  __ movq(kScratchRegister, Operand(rdx, -1 * kPointerSize));  // Skip receiver.
-  __ movq(FieldOperand(rdi, FixedArray::kHeaderSize), kScratchRegister);
-  __ addq(rdi, Immediate(kPointerSize));
-  __ subq(rdx, Immediate(kPointerSize));
-  __ decl(rcx);
-  __ j(not_zero, &loop);
-
-  // Return and remove the on-stack parameters.
-  __ bind(&done);
-  __ ret(3 * kPointerSize);
-
-  // Do the runtime call to allocate the arguments object.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kNewArgumentsFast, 3, 1);
-}
-
-
-void RegExpExecStub::Generate(MacroAssembler* masm) {
-  // Just jump directly to runtime if native RegExp is not selected at compile
-  // time or if regexp entry in generated code is turned off runtime switch or
-  // at compilation.
-#ifdef V8_INTERPRETED_REGEXP
-  __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
-#else  // V8_INTERPRETED_REGEXP
-  if (!FLAG_regexp_entry_native) {
-    __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
-    return;
-  }
-
-  // Stack frame on entry.
-  //  esp[0]: return address
-  //  esp[8]: last_match_info (expected JSArray)
-  //  esp[16]: previous index
-  //  esp[24]: subject string
-  //  esp[32]: JSRegExp object
-
-  static const int kLastMatchInfoOffset = 1 * kPointerSize;
-  static const int kPreviousIndexOffset = 2 * kPointerSize;
-  static const int kSubjectOffset = 3 * kPointerSize;
-  static const int kJSRegExpOffset = 4 * kPointerSize;
-
-  Label runtime;
-
-  // Ensure that a RegExp stack is allocated.
-  ExternalReference address_of_regexp_stack_memory_address =
-      ExternalReference::address_of_regexp_stack_memory_address();
-  ExternalReference address_of_regexp_stack_memory_size =
-      ExternalReference::address_of_regexp_stack_memory_size();
-  __ movq(kScratchRegister, address_of_regexp_stack_memory_size);
-  __ movq(kScratchRegister, Operand(kScratchRegister, 0));
-  __ testq(kScratchRegister, kScratchRegister);
-  __ j(zero, &runtime);
-
-
-  // Check that the first argument is a JSRegExp object.
-  __ movq(rax, Operand(rsp, kJSRegExpOffset));
-  __ JumpIfSmi(rax, &runtime);
-  __ CmpObjectType(rax, JS_REGEXP_TYPE, kScratchRegister);
-  __ j(not_equal, &runtime);
-  // Check that the RegExp has been compiled (data contains a fixed array).
-  __ movq(rcx, FieldOperand(rax, JSRegExp::kDataOffset));
-  if (FLAG_debug_code) {
-    Condition is_smi = masm->CheckSmi(rcx);
-    __ Check(NegateCondition(is_smi),
-        "Unexpected type for RegExp data, FixedArray expected");
-    __ CmpObjectType(rcx, FIXED_ARRAY_TYPE, kScratchRegister);
-    __ Check(equal, "Unexpected type for RegExp data, FixedArray expected");
-  }
-
-  // rcx: RegExp data (FixedArray)
-  // Check the type of the RegExp. Only continue if type is JSRegExp::IRREGEXP.
-  __ SmiToInteger32(rbx, FieldOperand(rcx, JSRegExp::kDataTagOffset));
-  __ cmpl(rbx, Immediate(JSRegExp::IRREGEXP));
-  __ j(not_equal, &runtime);
-
-  // rcx: RegExp data (FixedArray)
-  // Check that the number of captures fit in the static offsets vector buffer.
-  __ SmiToInteger32(rdx,
-                    FieldOperand(rcx, JSRegExp::kIrregexpCaptureCountOffset));
-  // Calculate number of capture registers (number_of_captures + 1) * 2.
-  __ leal(rdx, Operand(rdx, rdx, times_1, 2));
-  // Check that the static offsets vector buffer is large enough.
-  __ cmpl(rdx, Immediate(OffsetsVector::kStaticOffsetsVectorSize));
-  __ j(above, &runtime);
-
-  // rcx: RegExp data (FixedArray)
-  // rdx: Number of capture registers
-  // Check that the second argument is a string.
-  __ movq(rax, Operand(rsp, kSubjectOffset));
-  __ JumpIfSmi(rax, &runtime);
-  Condition is_string = masm->IsObjectStringType(rax, rbx, rbx);
-  __ j(NegateCondition(is_string), &runtime);
-
-  // rax: Subject string.
-  // rcx: RegExp data (FixedArray).
-  // rdx: Number of capture registers.
-  // Check that the third argument is a positive smi less than the string
-  // length. A negative value will be greater (unsigned comparison).
-  __ movq(rbx, Operand(rsp, kPreviousIndexOffset));
-  __ JumpIfNotSmi(rbx, &runtime);
-  __ SmiCompare(rbx, FieldOperand(rax, String::kLengthOffset));
-  __ j(above_equal, &runtime);
-
-  // rcx: RegExp data (FixedArray)
-  // rdx: Number of capture registers
-  // Check that the fourth object is a JSArray object.
-  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
-  __ JumpIfSmi(rax, &runtime);
-  __ CmpObjectType(rax, JS_ARRAY_TYPE, kScratchRegister);
-  __ j(not_equal, &runtime);
-  // Check that the JSArray is in fast case.
-  __ movq(rbx, FieldOperand(rax, JSArray::kElementsOffset));
-  __ movq(rax, FieldOperand(rbx, HeapObject::kMapOffset));
-  __ Cmp(rax, Factory::fixed_array_map());
-  __ j(not_equal, &runtime);
-  // Check that the last match info has space for the capture registers and the
-  // additional information. Ensure no overflow in add.
-  STATIC_ASSERT(FixedArray::kMaxLength < kMaxInt - FixedArray::kLengthOffset);
-  __ SmiToInteger32(rax, FieldOperand(rbx, FixedArray::kLengthOffset));
-  __ addl(rdx, Immediate(RegExpImpl::kLastMatchOverhead));
-  __ cmpl(rdx, rax);
-  __ j(greater, &runtime);
-
-  // rcx: RegExp data (FixedArray)
-  // Check the representation and encoding of the subject string.
-  Label seq_ascii_string, seq_two_byte_string, check_code;
-  __ movq(rax, Operand(rsp, kSubjectOffset));
-  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-  // First check for flat two byte string.
-  __ andb(rbx, Immediate(
-      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask));
-  STATIC_ASSERT((kStringTag | kSeqStringTag | kTwoByteStringTag) == 0);
-  __ j(zero, &seq_two_byte_string);
-  // Any other flat string must be a flat ascii string.
-  __ testb(rbx, Immediate(kIsNotStringMask | kStringRepresentationMask));
-  __ j(zero, &seq_ascii_string);
-
-  // Check for flat cons string.
-  // A flat cons string is a cons string where the second part is the empty
-  // string. In that case the subject string is just the first part of the cons
-  // string. Also in this case the first part of the cons string is known to be
-  // a sequential string or an external string.
-  STATIC_ASSERT(kExternalStringTag !=0);
-  STATIC_ASSERT((kConsStringTag & kExternalStringTag) == 0);
-  __ testb(rbx, Immediate(kIsNotStringMask | kExternalStringTag));
-  __ j(not_zero, &runtime);
-  // String is a cons string.
-  __ movq(rdx, FieldOperand(rax, ConsString::kSecondOffset));
-  __ Cmp(rdx, Factory::empty_string());
-  __ j(not_equal, &runtime);
-  __ movq(rax, FieldOperand(rax, ConsString::kFirstOffset));
-  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
-  // String is a cons string with empty second part.
-  // rax: first part of cons string.
-  // rbx: map of first part of cons string.
-  // Is first part a flat two byte string?
-  __ testb(FieldOperand(rbx, Map::kInstanceTypeOffset),
-           Immediate(kStringRepresentationMask | kStringEncodingMask));
-  STATIC_ASSERT((kSeqStringTag | kTwoByteStringTag) == 0);
-  __ j(zero, &seq_two_byte_string);
-  // Any other flat string must be ascii.
-  __ testb(FieldOperand(rbx, Map::kInstanceTypeOffset),
-           Immediate(kStringRepresentationMask));
-  __ j(not_zero, &runtime);
-
-  __ bind(&seq_ascii_string);
-  // rax: subject string (sequential ascii)
-  // rcx: RegExp data (FixedArray)
-  __ movq(r11, FieldOperand(rcx, JSRegExp::kDataAsciiCodeOffset));
-  __ Set(rdi, 1);  // Type is ascii.
-  __ jmp(&check_code);
-
-  __ bind(&seq_two_byte_string);
-  // rax: subject string (flat two-byte)
-  // rcx: RegExp data (FixedArray)
-  __ movq(r11, FieldOperand(rcx, JSRegExp::kDataUC16CodeOffset));
-  __ Set(rdi, 0);  // Type is two byte.
-
-  __ bind(&check_code);
-  // Check that the irregexp code has been generated for the actual string
-  // encoding. If it has, the field contains a code object otherwise it contains
-  // the hole.
-  __ CmpObjectType(r11, CODE_TYPE, kScratchRegister);
-  __ j(not_equal, &runtime);
-
-  // rax: subject string
-  // rdi: encoding of subject string (1 if ascii, 0 if two_byte);
-  // r11: code
-  // Load used arguments before starting to push arguments for call to native
-  // RegExp code to avoid handling changing stack height.
-  __ SmiToInteger64(rbx, Operand(rsp, kPreviousIndexOffset));
-
-  // rax: subject string
-  // rbx: previous index
-  // rdi: encoding of subject string (1 if ascii 0 if two_byte);
-  // r11: code
-  // All checks done. Now push arguments for native regexp code.
-  __ IncrementCounter(&Counters::regexp_entry_native, 1);
-
-  // rsi is caller save on Windows and used to pass parameter on Linux.
-  __ push(rsi);
-
-  static const int kRegExpExecuteArguments = 7;
-  __ PrepareCallCFunction(kRegExpExecuteArguments);
-  int argument_slots_on_stack =
-      masm->ArgumentStackSlotsForCFunctionCall(kRegExpExecuteArguments);
-
-  // Argument 7: Indicate that this is a direct call from JavaScript.
-  __ movq(Operand(rsp, (argument_slots_on_stack - 1) * kPointerSize),
-          Immediate(1));
-
-  // Argument 6: Start (high end) of backtracking stack memory area.
-  __ movq(kScratchRegister, address_of_regexp_stack_memory_address);
-  __ movq(r9, Operand(kScratchRegister, 0));
-  __ movq(kScratchRegister, address_of_regexp_stack_memory_size);
-  __ addq(r9, Operand(kScratchRegister, 0));
-  // Argument 6 passed in r9 on Linux and on the stack on Windows.
-#ifdef _WIN64
-  __ movq(Operand(rsp, (argument_slots_on_stack - 2) * kPointerSize), r9);
-#endif
-
-  // Argument 5: static offsets vector buffer.
-  __ movq(r8, ExternalReference::address_of_static_offsets_vector());
-  // Argument 5 passed in r8 on Linux and on the stack on Windows.
-#ifdef _WIN64
-  __ movq(Operand(rsp, (argument_slots_on_stack - 3) * kPointerSize), r8);
-#endif
-
-  // First four arguments are passed in registers on both Linux and Windows.
-#ifdef _WIN64
-  Register arg4 = r9;
-  Register arg3 = r8;
-  Register arg2 = rdx;
-  Register arg1 = rcx;
-#else
-  Register arg4 = rcx;
-  Register arg3 = rdx;
-  Register arg2 = rsi;
-  Register arg1 = rdi;
-#endif
-
-  // Keep track on aliasing between argX defined above and the registers used.
-  // rax: subject string
-  // rbx: previous index
-  // rdi: encoding of subject string (1 if ascii 0 if two_byte);
-  // r11: code
-
-  // Argument 4: End of string data
-  // Argument 3: Start of string data
-  Label setup_two_byte, setup_rest;
-  __ testb(rdi, rdi);
-  __ j(zero, &setup_two_byte);
-  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
-  __ lea(arg4, FieldOperand(rax, rdi, times_1, SeqAsciiString::kHeaderSize));
-  __ lea(arg3, FieldOperand(rax, rbx, times_1, SeqAsciiString::kHeaderSize));
-  __ jmp(&setup_rest);
-  __ bind(&setup_two_byte);
-  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
-  __ lea(arg4, FieldOperand(rax, rdi, times_2, SeqTwoByteString::kHeaderSize));
-  __ lea(arg3, FieldOperand(rax, rbx, times_2, SeqTwoByteString::kHeaderSize));
-
-  __ bind(&setup_rest);
-  // Argument 2: Previous index.
-  __ movq(arg2, rbx);
-
-  // Argument 1: Subject string.
-  __ movq(arg1, rax);
-
-  // Locate the code entry and call it.
-  __ addq(r11, Immediate(Code::kHeaderSize - kHeapObjectTag));
-  __ CallCFunction(r11, kRegExpExecuteArguments);
-
-  // rsi is caller save, as it is used to pass parameter.
-  __ pop(rsi);
-
-  // Check the result.
-  Label success;
-  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::SUCCESS));
-  __ j(equal, &success);
-  Label failure;
-  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::FAILURE));
-  __ j(equal, &failure);
-  __ cmpl(rax, Immediate(NativeRegExpMacroAssembler::EXCEPTION));
-  // If not exception it can only be retry. Handle that in the runtime system.
-  __ j(not_equal, &runtime);
-  // Result must now be exception. If there is no pending exception already a
-  // stack overflow (on the backtrack stack) was detected in RegExp code but
-  // haven't created the exception yet. Handle that in the runtime system.
-  // TODO(592): Rerunning the RegExp to get the stack overflow exception.
-  ExternalReference pending_exception_address(Top::k_pending_exception_address);
-  __ movq(kScratchRegister, pending_exception_address);
-  __ Cmp(kScratchRegister, Factory::the_hole_value());
-  __ j(equal, &runtime);
-  __ bind(&failure);
-  // For failure and exception return null.
-  __ Move(rax, Factory::null_value());
-  __ ret(4 * kPointerSize);
-
-  // Load RegExp data.
-  __ bind(&success);
-  __ movq(rax, Operand(rsp, kJSRegExpOffset));
-  __ movq(rcx, FieldOperand(rax, JSRegExp::kDataOffset));
-  __ SmiToInteger32(rax,
-                    FieldOperand(rcx, JSRegExp::kIrregexpCaptureCountOffset));
-  // Calculate number of capture registers (number_of_captures + 1) * 2.
-  __ leal(rdx, Operand(rax, rax, times_1, 2));
-
-  // rdx: Number of capture registers
-  // Load last_match_info which is still known to be a fast case JSArray.
-  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
-  __ movq(rbx, FieldOperand(rax, JSArray::kElementsOffset));
-
-  // rbx: last_match_info backing store (FixedArray)
-  // rdx: number of capture registers
-  // Store the capture count.
-  __ Integer32ToSmi(kScratchRegister, rdx);
-  __ movq(FieldOperand(rbx, RegExpImpl::kLastCaptureCountOffset),
-          kScratchRegister);
-  // Store last subject and last input.
-  __ movq(rax, Operand(rsp, kSubjectOffset));
-  __ movq(FieldOperand(rbx, RegExpImpl::kLastSubjectOffset), rax);
-  __ movq(rcx, rbx);
-  __ RecordWrite(rcx, RegExpImpl::kLastSubjectOffset, rax, rdi);
-  __ movq(rax, Operand(rsp, kSubjectOffset));
-  __ movq(FieldOperand(rbx, RegExpImpl::kLastInputOffset), rax);
-  __ movq(rcx, rbx);
-  __ RecordWrite(rcx, RegExpImpl::kLastInputOffset, rax, rdi);
-
-  // Get the static offsets vector filled by the native regexp code.
-  __ movq(rcx, ExternalReference::address_of_static_offsets_vector());
-
-  // rbx: last_match_info backing store (FixedArray)
-  // rcx: offsets vector
-  // rdx: number of capture registers
-  Label next_capture, done;
-  // Capture register counter starts from number of capture registers and
-  // counts down until wraping after zero.
-  __ bind(&next_capture);
-  __ subq(rdx, Immediate(1));
-  __ j(negative, &done);
-  // Read the value from the static offsets vector buffer and make it a smi.
-  __ movl(rdi, Operand(rcx, rdx, times_int_size, 0));
-  __ Integer32ToSmi(rdi, rdi, &runtime);
-  // Store the smi value in the last match info.
-  __ movq(FieldOperand(rbx,
-                       rdx,
-                       times_pointer_size,
-                       RegExpImpl::kFirstCaptureOffset),
-          rdi);
-  __ jmp(&next_capture);
-  __ bind(&done);
-
-  // Return last match info.
-  __ movq(rax, Operand(rsp, kLastMatchInfoOffset));
-  __ ret(4 * kPointerSize);
-
-  // Do the runtime call to execute the regexp.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
-#endif  // V8_INTERPRETED_REGEXP
-}
-
-
-void NumberToStringStub::GenerateLookupNumberStringCache(MacroAssembler* masm,
-                                                         Register object,
-                                                         Register result,
-                                                         Register scratch1,
-                                                         Register scratch2,
-                                                         bool object_is_smi,
-                                                         Label* not_found) {
-  // Use of registers. Register result is used as a temporary.
-  Register number_string_cache = result;
-  Register mask = scratch1;
-  Register scratch = scratch2;
-
-  // Load the number string cache.
-  __ LoadRoot(number_string_cache, Heap::kNumberStringCacheRootIndex);
-
-  // Make the hash mask from the length of the number string cache. It
-  // contains two elements (number and string) for each cache entry.
-  __ SmiToInteger32(
-      mask, FieldOperand(number_string_cache, FixedArray::kLengthOffset));
-  __ shrl(mask, Immediate(1));
-  __ subq(mask, Immediate(1));  // Make mask.
-
-  // Calculate the entry in the number string cache. The hash value in the
-  // number string cache for smis is just the smi value, and the hash for
-  // doubles is the xor of the upper and lower words. See
-  // Heap::GetNumberStringCache.
-  Label is_smi;
-  Label load_result_from_cache;
-  if (!object_is_smi) {
-    __ JumpIfSmi(object, &is_smi);
-    __ CheckMap(object, Factory::heap_number_map(), not_found, true);
-
-    STATIC_ASSERT(8 == kDoubleSize);
-    __ movl(scratch, FieldOperand(object, HeapNumber::kValueOffset + 4));
-    __ xor_(scratch, FieldOperand(object, HeapNumber::kValueOffset));
-    GenerateConvertHashCodeToIndex(masm, scratch, mask);
-
-    Register index = scratch;
-    Register probe = mask;
-    __ movq(probe,
-            FieldOperand(number_string_cache,
-                         index,
-                         times_1,
-                         FixedArray::kHeaderSize));
-    __ JumpIfSmi(probe, not_found);
-    ASSERT(CpuFeatures::IsSupported(SSE2));
-    CpuFeatures::Scope fscope(SSE2);
-    __ movsd(xmm0, FieldOperand(object, HeapNumber::kValueOffset));
-    __ movsd(xmm1, FieldOperand(probe, HeapNumber::kValueOffset));
-    __ ucomisd(xmm0, xmm1);
-    __ j(parity_even, not_found);  // Bail out if NaN is involved.
-    __ j(not_equal, not_found);  // The cache did not contain this value.
-    __ jmp(&load_result_from_cache);
-  }
-
-  __ bind(&is_smi);
-  __ SmiToInteger32(scratch, object);
-  GenerateConvertHashCodeToIndex(masm, scratch, mask);
-
-  Register index = scratch;
-  // Check if the entry is the smi we are looking for.
-  __ cmpq(object,
-          FieldOperand(number_string_cache,
-                       index,
-                       times_1,
-                       FixedArray::kHeaderSize));
-  __ j(not_equal, not_found);
-
-  // Get the result from the cache.
-  __ bind(&load_result_from_cache);
-  __ movq(result,
-          FieldOperand(number_string_cache,
-                       index,
-                       times_1,
-                       FixedArray::kHeaderSize + kPointerSize));
-  __ IncrementCounter(&Counters::number_to_string_native, 1);
-}
-
-
-void NumberToStringStub::GenerateConvertHashCodeToIndex(MacroAssembler* masm,
-                                                        Register hash,
-                                                        Register mask) {
-  __ and_(hash, mask);
-  // Each entry in string cache consists of two pointer sized fields,
-  // but times_twice_pointer_size (multiplication by 16) scale factor
-  // is not supported by addrmode on x64 platform.
-  // So we have to premultiply entry index before lookup.
-  __ shl(hash, Immediate(kPointerSizeLog2 + 1));
-}
-
-
-void NumberToStringStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  __ movq(rbx, Operand(rsp, kPointerSize));
-
-  // Generate code to lookup number in the number string cache.
-  GenerateLookupNumberStringCache(masm, rbx, rax, r8, r9, false, &runtime);
-  __ ret(1 * kPointerSize);
-
-  __ bind(&runtime);
-  // Handle number to string in the runtime system if not found in the cache.
-  __ TailCallRuntime(Runtime::kNumberToStringSkipCache, 1, 1);
-}
-
-
-static int NegativeComparisonResult(Condition cc) {
-  ASSERT(cc != equal);
-  ASSERT((cc == less) || (cc == less_equal)
-      || (cc == greater) || (cc == greater_equal));
-  return (cc == greater || cc == greater_equal) ? LESS : GREATER;
-}
-
-
-void CompareStub::Generate(MacroAssembler* masm) {
-  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
-
-  Label check_unequal_objects, done;
-  // The compare stub returns a positive, negative, or zero 64-bit integer
-  // value in rax, corresponding to result of comparing the two inputs.
-  // NOTICE! This code is only reached after a smi-fast-case check, so
-  // it is certain that at least one operand isn't a smi.
-
-  // Two identical objects are equal unless they are both NaN or undefined.
-  {
-    Label not_identical;
-    __ cmpq(rax, rdx);
-    __ j(not_equal, &not_identical);
-
-    if (cc_ != equal) {
-      // Check for undefined.  undefined OP undefined is false even though
-      // undefined == undefined.
-      Label check_for_nan;
-      __ CompareRoot(rdx, Heap::kUndefinedValueRootIndex);
-      __ j(not_equal, &check_for_nan);
-      __ Set(rax, NegativeComparisonResult(cc_));
-      __ ret(0);
-      __ bind(&check_for_nan);
-    }
-
-    // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
-    // so we do the second best thing - test it ourselves.
-    // Note: if cc_ != equal, never_nan_nan_ is not used.
-    // We cannot set rax to EQUAL until just before return because
-    // rax must be unchanged on jump to not_identical.
-
-    if (never_nan_nan_ && (cc_ == equal)) {
-      __ Set(rax, EQUAL);
-      __ ret(0);
-    } else {
-      Label heap_number;
-      // If it's not a heap number, then return equal for (in)equality operator.
-      __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
-             Factory::heap_number_map());
-      __ j(equal, &heap_number);
-      if (cc_ != equal) {
-        // Call runtime on identical JSObjects.  Otherwise return equal.
-        __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rcx);
-        __ j(above_equal, &not_identical);
-      }
-      __ Set(rax, EQUAL);
-      __ ret(0);
-
-      __ bind(&heap_number);
-      // It is a heap number, so return  equal if it's not NaN.
-      // For NaN, return 1 for every condition except greater and
-      // greater-equal.  Return -1 for them, so the comparison yields
-      // false for all conditions except not-equal.
-      __ Set(rax, EQUAL);
-      __ movsd(xmm0, FieldOperand(rdx, HeapNumber::kValueOffset));
-      __ ucomisd(xmm0, xmm0);
-      __ setcc(parity_even, rax);
-      // rax is 0 for equal non-NaN heapnumbers, 1 for NaNs.
-      if (cc_ == greater_equal || cc_ == greater) {
-        __ neg(rax);
-      }
-      __ ret(0);
-    }
-
-    __ bind(&not_identical);
-  }
-
-  if (cc_ == equal) {  // Both strict and non-strict.
-    Label slow;  // Fallthrough label.
-
-    // If we're doing a strict equality comparison, we don't have to do
-    // type conversion, so we generate code to do fast comparison for objects
-    // and oddballs. Non-smi numbers and strings still go through the usual
-    // slow-case code.
-    if (strict_) {
-      // If either is a Smi (we know that not both are), then they can only
-      // be equal if the other is a HeapNumber. If so, use the slow case.
-      {
-        Label not_smis;
-        __ SelectNonSmi(rbx, rax, rdx, &not_smis);
-
-        // Check if the non-smi operand is a heap number.
-        __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
-               Factory::heap_number_map());
-        // If heap number, handle it in the slow case.
-        __ j(equal, &slow);
-        // Return non-equal.  ebx (the lower half of rbx) is not zero.
-        __ movq(rax, rbx);
-        __ ret(0);
-
-        __ bind(&not_smis);
-      }
-
-      // If either operand is a JSObject or an oddball value, then they are not
-      // equal since their pointers are different
-      // There is no test for undetectability in strict equality.
-
-      // If the first object is a JS object, we have done pointer comparison.
-      STATIC_ASSERT(LAST_TYPE == JS_FUNCTION_TYPE);
-      Label first_non_object;
-      __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rcx);
-      __ j(below, &first_non_object);
-      // Return non-zero (eax (not rax) is not zero)
-      Label return_not_equal;
-      STATIC_ASSERT(kHeapObjectTag != 0);
-      __ bind(&return_not_equal);
-      __ ret(0);
-
-      __ bind(&first_non_object);
-      // Check for oddballs: true, false, null, undefined.
-      __ CmpInstanceType(rcx, ODDBALL_TYPE);
-      __ j(equal, &return_not_equal);
-
-      __ CmpObjectType(rdx, FIRST_JS_OBJECT_TYPE, rcx);
-      __ j(above_equal, &return_not_equal);
-
-      // Check for oddballs: true, false, null, undefined.
-      __ CmpInstanceType(rcx, ODDBALL_TYPE);
-      __ j(equal, &return_not_equal);
-
-      // Fall through to the general case.
-    }
-    __ bind(&slow);
-  }
-
-  // Generate the number comparison code.
-  if (include_number_compare_) {
-    Label non_number_comparison;
-    Label unordered;
-    FloatingPointHelper::LoadSSE2UnknownOperands(masm, &non_number_comparison);
-    __ xorl(rax, rax);
-    __ xorl(rcx, rcx);
-    __ ucomisd(xmm0, xmm1);
-
-    // Don't base result on EFLAGS when a NaN is involved.
-    __ j(parity_even, &unordered);
-    // Return a result of -1, 0, or 1, based on EFLAGS.
-    __ setcc(above, rax);
-    __ setcc(below, rcx);
-    __ subq(rax, rcx);
-    __ ret(0);
-
-    // If one of the numbers was NaN, then the result is always false.
-    // The cc is never not-equal.
-    __ bind(&unordered);
-    ASSERT(cc_ != not_equal);
-    if (cc_ == less || cc_ == less_equal) {
-      __ Set(rax, 1);
-    } else {
-      __ Set(rax, -1);
-    }
-    __ ret(0);
-
-    // The number comparison code did not provide a valid result.
-    __ bind(&non_number_comparison);
-  }
-
-  // Fast negative check for symbol-to-symbol equality.
-  Label check_for_strings;
-  if (cc_ == equal) {
-    BranchIfNonSymbol(masm, &check_for_strings, rax, kScratchRegister);
-    BranchIfNonSymbol(masm, &check_for_strings, rdx, kScratchRegister);
-
-    // We've already checked for object identity, so if both operands
-    // are symbols they aren't equal. Register eax (not rax) already holds a
-    // non-zero value, which indicates not equal, so just return.
-    __ ret(0);
-  }
-
-  __ bind(&check_for_strings);
-
-  __ JumpIfNotBothSequentialAsciiStrings(
-      rdx, rax, rcx, rbx, &check_unequal_objects);
-
-  // Inline comparison of ascii strings.
-  StringCompareStub::GenerateCompareFlatAsciiStrings(masm,
-                                                     rdx,
-                                                     rax,
-                                                     rcx,
-                                                     rbx,
-                                                     rdi,
-                                                     r8);
-
-#ifdef DEBUG
-  __ Abort("Unexpected fall-through from string comparison");
-#endif
-
-  __ bind(&check_unequal_objects);
-  if (cc_ == equal && !strict_) {
-    // Not strict equality.  Objects are unequal if
-    // they are both JSObjects and not undetectable,
-    // and their pointers are different.
-    Label not_both_objects, return_unequal;
-    // At most one is a smi, so we can test for smi by adding the two.
-    // A smi plus a heap object has the low bit set, a heap object plus
-    // a heap object has the low bit clear.
-    STATIC_ASSERT(kSmiTag == 0);
-    STATIC_ASSERT(kSmiTagMask == 1);
-    __ lea(rcx, Operand(rax, rdx, times_1, 0));
-    __ testb(rcx, Immediate(kSmiTagMask));
-    __ j(not_zero, &not_both_objects);
-    __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rbx);
-    __ j(below, &not_both_objects);
-    __ CmpObjectType(rdx, FIRST_JS_OBJECT_TYPE, rcx);
-    __ j(below, &not_both_objects);
-    __ testb(FieldOperand(rbx, Map::kBitFieldOffset),
-             Immediate(1 << Map::kIsUndetectable));
-    __ j(zero, &return_unequal);
-    __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
-             Immediate(1 << Map::kIsUndetectable));
-    __ j(zero, &return_unequal);
-    // The objects are both undetectable, so they both compare as the value
-    // undefined, and are equal.
-    __ Set(rax, EQUAL);
-    __ bind(&return_unequal);
-    // Return non-equal by returning the non-zero object pointer in eax,
-    // or return equal if we fell through to here.
-    __ ret(0);
-    __ bind(&not_both_objects);
-  }
-
-  // Push arguments below the return address to prepare jump to builtin.
-  __ pop(rcx);
-  __ push(rdx);
-  __ push(rax);
-
-  // Figure out which native to call and setup the arguments.
-  Builtins::JavaScript builtin;
-  if (cc_ == equal) {
-    builtin = strict_ ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
-  } else {
-    builtin = Builtins::COMPARE;
-    __ Push(Smi::FromInt(NegativeComparisonResult(cc_)));
-  }
-
-  // Restore return address on the stack.
-  __ push(rcx);
-
-  // Call the native; it returns -1 (less), 0 (equal), or 1 (greater)
-  // tagged as a small integer.
-  __ InvokeBuiltin(builtin, JUMP_FUNCTION);
-}
-
-
-void CompareStub::BranchIfNonSymbol(MacroAssembler* masm,
-                                    Label* label,
-                                    Register object,
-                                    Register scratch) {
-  __ JumpIfSmi(object, label);
-  __ movq(scratch, FieldOperand(object, HeapObject::kMapOffset));
-  __ movzxbq(scratch,
-             FieldOperand(scratch, Map::kInstanceTypeOffset));
-  // Ensure that no non-strings have the symbol bit set.
-  STATIC_ASSERT(LAST_TYPE < kNotStringTag + kIsSymbolMask);
-  STATIC_ASSERT(kSymbolTag != 0);
-  __ testb(scratch, Immediate(kIsSymbolMask));
-  __ j(zero, label);
-}
-
-
-void StackCheckStub::Generate(MacroAssembler* masm) {
-  // Because builtins always remove the receiver from the stack, we
-  // have to fake one to avoid underflowing the stack. The receiver
-  // must be inserted below the return address on the stack so we
-  // temporarily store that in a register.
-  __ pop(rax);
-  __ Push(Smi::FromInt(0));
-  __ push(rax);
-
-  // Do tail-call to runtime routine.
-  __ TailCallRuntime(Runtime::kStackGuard, 1, 1);
-}
-
-
-void CallFunctionStub::Generate(MacroAssembler* masm) {
-  Label slow;
-
-  // If the receiver might be a value (string, number or boolean) check for this
-  // and box it if it is.
-  if (ReceiverMightBeValue()) {
-    // Get the receiver from the stack.
-    // +1 ~ return address
-    Label receiver_is_value, receiver_is_js_object;
-    __ movq(rax, Operand(rsp, (argc_ + 1) * kPointerSize));
-
-    // Check if receiver is a smi (which is a number value).
-    __ JumpIfSmi(rax, &receiver_is_value);
-
-    // Check if the receiver is a valid JS object.
-    __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rdi);
-    __ j(above_equal, &receiver_is_js_object);
-
-    // Call the runtime to box the value.
-    __ bind(&receiver_is_value);
-    __ EnterInternalFrame();
-    __ push(rax);
-    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
-    __ LeaveInternalFrame();
-    __ movq(Operand(rsp, (argc_ + 1) * kPointerSize), rax);
-
-    __ bind(&receiver_is_js_object);
-  }
-
-  // Get the function to call from the stack.
-  // +2 ~ receiver, return address
-  __ movq(rdi, Operand(rsp, (argc_ + 2) * kPointerSize));
-
-  // Check that the function really is a JavaScript function.
-  __ JumpIfSmi(rdi, &slow);
-  // Goto slow case if we do not have a function.
-  __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
-  __ j(not_equal, &slow);
-
-  // Fast-case: Just invoke the function.
-  ParameterCount actual(argc_);
-  __ InvokeFunction(rdi, actual, JUMP_FUNCTION);
-
-  // Slow-case: Non-function called.
-  __ bind(&slow);
-  // CALL_NON_FUNCTION expects the non-function callee as receiver (instead
-  // of the original receiver from the call site).
-  __ movq(Operand(rsp, (argc_ + 1) * kPointerSize), rdi);
-  __ Set(rax, argc_);
-  __ Set(rbx, 0);
-  __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION);
-  Handle<Code> adaptor(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
-  __ Jump(adaptor, RelocInfo::CODE_TARGET);
-}
-
-
-void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
-  // Check that stack should contain next handler, frame pointer, state and
-  // return address in that order.
-  STATIC_ASSERT(StackHandlerConstants::kFPOffset + kPointerSize ==
-            StackHandlerConstants::kStateOffset);
-  STATIC_ASSERT(StackHandlerConstants::kStateOffset + kPointerSize ==
-            StackHandlerConstants::kPCOffset);
-
-  ExternalReference handler_address(Top::k_handler_address);
-  __ movq(kScratchRegister, handler_address);
-  __ movq(rsp, Operand(kScratchRegister, 0));
-  // get next in chain
-  __ pop(rcx);
-  __ movq(Operand(kScratchRegister, 0), rcx);
-  __ pop(rbp);  // pop frame pointer
-  __ pop(rdx);  // remove state
-
-  // Before returning we restore the context from the frame pointer if not NULL.
-  // The frame pointer is NULL in the exception handler of a JS entry frame.
-  __ xor_(rsi, rsi);  // tentatively set context pointer to NULL
-  Label skip;
-  __ cmpq(rbp, Immediate(0));
-  __ j(equal, &skip);
-  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
-  __ bind(&skip);
-  __ ret(0);
-}
-
-
-void ApiGetterEntryStub::Generate(MacroAssembler* masm) {
-  Label empty_result;
-  Label prologue;
-  Label promote_scheduled_exception;
-  __ EnterApiExitFrame(ExitFrame::MODE_NORMAL, kStackSpace, 0);
-  ASSERT_EQ(kArgc, 4);
-#ifdef _WIN64
-  // All the parameters should be set up by a caller.
-#else
-  // Set 1st parameter register with property name.
-  __ movq(rsi, rdx);
-  // Second parameter register rdi should be set with pointer to AccessorInfo
-  // by a caller.
-#endif
-  // Call the api function!
-  __ movq(rax,
-          reinterpret_cast<int64_t>(fun()->address()),
-          RelocInfo::RUNTIME_ENTRY);
-  __ call(rax);
-  // Check if the function scheduled an exception.
-  ExternalReference scheduled_exception_address =
-      ExternalReference::scheduled_exception_address();
-  __ movq(rsi, scheduled_exception_address);
-  __ Cmp(Operand(rsi, 0), Factory::the_hole_value());
-  __ j(not_equal, &promote_scheduled_exception);
-#ifdef _WIN64
-  // rax keeps a pointer to v8::Handle, unpack it.
-  __ movq(rax, Operand(rax, 0));
-#endif
-  // Check if the result handle holds 0.
-  __ testq(rax, rax);
-  __ j(zero, &empty_result);
-  // It was non-zero.  Dereference to get the result value.
-  __ movq(rax, Operand(rax, 0));
-  __ bind(&prologue);
-  __ LeaveExitFrame(ExitFrame::MODE_NORMAL);
-  __ ret(0);
-  __ bind(&promote_scheduled_exception);
-  __ TailCallRuntime(Runtime::kPromoteScheduledException, 0, 1);
-  __ bind(&empty_result);
-  // It was zero; the result is undefined.
-  __ Move(rax, Factory::undefined_value());
-  __ jmp(&prologue);
-}
-
-
-void CEntryStub::GenerateCore(MacroAssembler* masm,
-                              Label* throw_normal_exception,
-                              Label* throw_termination_exception,
-                              Label* throw_out_of_memory_exception,
-                              bool do_gc,
-                              bool always_allocate_scope,
-                              int /* alignment_skew */) {
-  // rax: result parameter for PerformGC, if any.
-  // rbx: pointer to C function  (C callee-saved).
-  // rbp: frame pointer  (restored after C call).
-  // rsp: stack pointer  (restored after C call).
-  // r14: number of arguments including receiver (C callee-saved).
-  // r12: pointer to the first argument (C callee-saved).
-  //      This pointer is reused in LeaveExitFrame(), so it is stored in a
-  //      callee-saved register.
-
-  // Simple results returned in rax (both AMD64 and Win64 calling conventions).
-  // Complex results must be written to address passed as first argument.
-  // AMD64 calling convention: a struct of two pointers in rax+rdx
-
-  // Check stack alignment.
-  if (FLAG_debug_code) {
-    __ CheckStackAlignment();
-  }
-
-  if (do_gc) {
-    // Pass failure code returned from last attempt as first argument to
-    // PerformGC. No need to use PrepareCallCFunction/CallCFunction here as the
-    // stack is known to be aligned. This function takes one argument which is
-    // passed in register.
-#ifdef _WIN64
-    __ movq(rcx, rax);
-#else  // _WIN64
-    __ movq(rdi, rax);
-#endif
-    __ movq(kScratchRegister,
-            FUNCTION_ADDR(Runtime::PerformGC),
-            RelocInfo::RUNTIME_ENTRY);
-    __ call(kScratchRegister);
-  }
-
-  ExternalReference scope_depth =
-      ExternalReference::heap_always_allocate_scope_depth();
-  if (always_allocate_scope) {
-    __ movq(kScratchRegister, scope_depth);
-    __ incl(Operand(kScratchRegister, 0));
-  }
-
-  // Call C function.
-#ifdef _WIN64
-  // Windows 64-bit ABI passes arguments in rcx, rdx, r8, r9
-  // Store Arguments object on stack, below the 4 WIN64 ABI parameter slots.
-  __ movq(Operand(rsp, 4 * kPointerSize), r14);  // argc.
-  __ movq(Operand(rsp, 5 * kPointerSize), r12);  // argv.
-  if (result_size_ < 2) {
-    // Pass a pointer to the Arguments object as the first argument.
-    // Return result in single register (rax).
-    __ lea(rcx, Operand(rsp, 4 * kPointerSize));
-  } else {
-    ASSERT_EQ(2, result_size_);
-    // Pass a pointer to the result location as the first argument.
-    __ lea(rcx, Operand(rsp, 6 * kPointerSize));
-    // Pass a pointer to the Arguments object as the second argument.
-    __ lea(rdx, Operand(rsp, 4 * kPointerSize));
-  }
-
-#else  // _WIN64
-  // GCC passes arguments in rdi, rsi, rdx, rcx, r8, r9.
-  __ movq(rdi, r14);  // argc.
-  __ movq(rsi, r12);  // argv.
-#endif
-  __ call(rbx);
-  // Result is in rax - do not destroy this register!
-
-  if (always_allocate_scope) {
-    __ movq(kScratchRegister, scope_depth);
-    __ decl(Operand(kScratchRegister, 0));
-  }
-
-  // Check for failure result.
-  Label failure_returned;
-  STATIC_ASSERT(((kFailureTag + 1) & kFailureTagMask) == 0);
-#ifdef _WIN64
-  // If return value is on the stack, pop it to registers.
-  if (result_size_ > 1) {
-    ASSERT_EQ(2, result_size_);
-    // Read result values stored on stack. Result is stored
-    // above the four argument mirror slots and the two
-    // Arguments object slots.
-    __ movq(rax, Operand(rsp, 6 * kPointerSize));
-    __ movq(rdx, Operand(rsp, 7 * kPointerSize));
-  }
-#endif
-  __ lea(rcx, Operand(rax, 1));
-  // Lower 2 bits of rcx are 0 iff rax has failure tag.
-  __ testl(rcx, Immediate(kFailureTagMask));
-  __ j(zero, &failure_returned);
-
-  // Exit the JavaScript to C++ exit frame.
-  __ LeaveExitFrame(mode_, result_size_);
-  __ ret(0);
-
-  // Handling of failure.
-  __ bind(&failure_returned);
-
-  Label retry;
-  // If the returned exception is RETRY_AFTER_GC continue at retry label
-  STATIC_ASSERT(Failure::RETRY_AFTER_GC == 0);
-  __ testl(rax, Immediate(((1 << kFailureTypeTagSize) - 1) << kFailureTagSize));
-  __ j(zero, &retry);
-
-  // Special handling of out of memory exceptions.
-  __ movq(kScratchRegister, Failure::OutOfMemoryException(), RelocInfo::NONE);
-  __ cmpq(rax, kScratchRegister);
-  __ j(equal, throw_out_of_memory_exception);
-
-  // Retrieve the pending exception and clear the variable.
-  ExternalReference pending_exception_address(Top::k_pending_exception_address);
-  __ movq(kScratchRegister, pending_exception_address);
-  __ movq(rax, Operand(kScratchRegister, 0));
-  __ movq(rdx, ExternalReference::the_hole_value_location());
-  __ movq(rdx, Operand(rdx, 0));
-  __ movq(Operand(kScratchRegister, 0), rdx);
-
-  // Special handling of termination exceptions which are uncatchable
-  // by javascript code.
-  __ CompareRoot(rax, Heap::kTerminationExceptionRootIndex);
-  __ j(equal, throw_termination_exception);
-
-  // Handle normal exception.
-  __ jmp(throw_normal_exception);
-
-  // Retry.
-  __ bind(&retry);
-}
-
-
-void CEntryStub::GenerateThrowUncatchable(MacroAssembler* masm,
-                                          UncatchableExceptionType type) {
-  // Fetch top stack handler.
-  ExternalReference handler_address(Top::k_handler_address);
-  __ movq(kScratchRegister, handler_address);
-  __ movq(rsp, Operand(kScratchRegister, 0));
-
-  // Unwind the handlers until the ENTRY handler is found.
-  Label loop, done;
-  __ bind(&loop);
-  // Load the type of the current stack handler.
-  const int kStateOffset = StackHandlerConstants::kStateOffset;
-  __ cmpq(Operand(rsp, kStateOffset), Immediate(StackHandler::ENTRY));
-  __ j(equal, &done);
-  // Fetch the next handler in the list.
-  const int kNextOffset = StackHandlerConstants::kNextOffset;
-  __ movq(rsp, Operand(rsp, kNextOffset));
-  __ jmp(&loop);
-  __ bind(&done);
-
-  // Set the top handler address to next handler past the current ENTRY handler.
-  __ movq(kScratchRegister, handler_address);
-  __ pop(Operand(kScratchRegister, 0));
-
-  if (type == OUT_OF_MEMORY) {
-    // Set external caught exception to false.
-    ExternalReference external_caught(Top::k_external_caught_exception_address);
-    __ movq(rax, Immediate(false));
-    __ store_rax(external_caught);
-
-    // Set pending exception and rax to out of memory exception.
-    ExternalReference pending_exception(Top::k_pending_exception_address);
-    __ movq(rax, Failure::OutOfMemoryException(), RelocInfo::NONE);
-    __ store_rax(pending_exception);
-  }
-
-  // Clear the context pointer.
-  __ xor_(rsi, rsi);
-
-  // Restore registers from handler.
-  STATIC_ASSERT(StackHandlerConstants::kNextOffset + kPointerSize ==
-            StackHandlerConstants::kFPOffset);
-  __ pop(rbp);  // FP
-  STATIC_ASSERT(StackHandlerConstants::kFPOffset + kPointerSize ==
-            StackHandlerConstants::kStateOffset);
-  __ pop(rdx);  // State
-
-  STATIC_ASSERT(StackHandlerConstants::kStateOffset + kPointerSize ==
-            StackHandlerConstants::kPCOffset);
-  __ ret(0);
-}
-
-
-void CEntryStub::Generate(MacroAssembler* masm) {
-  // rax: number of arguments including receiver
-  // rbx: pointer to C function  (C callee-saved)
-  // rbp: frame pointer of calling JS frame (restored after C call)
-  // rsp: stack pointer  (restored after C call)
-  // rsi: current context (restored)
-
-  // NOTE: Invocations of builtins may return failure objects
-  // instead of a proper result. The builtin entry handles
-  // this by performing a garbage collection and retrying the
-  // builtin once.
-
-  // Enter the exit frame that transitions from JavaScript to C++.
-  __ EnterExitFrame(mode_, result_size_);
-
-  // rax: Holds the context at this point, but should not be used.
-  //      On entry to code generated by GenerateCore, it must hold
-  //      a failure result if the collect_garbage argument to GenerateCore
-  //      is true.  This failure result can be the result of code
-  //      generated by a previous call to GenerateCore.  The value
-  //      of rax is then passed to Runtime::PerformGC.
-  // rbx: pointer to builtin function  (C callee-saved).
-  // rbp: frame pointer of exit frame  (restored after C call).
-  // rsp: stack pointer (restored after C call).
-  // r14: number of arguments including receiver (C callee-saved).
-  // r12: argv pointer (C callee-saved).
-
-  Label throw_normal_exception;
-  Label throw_termination_exception;
-  Label throw_out_of_memory_exception;
-
-  // Call into the runtime system.
-  GenerateCore(masm,
-               &throw_normal_exception,
-               &throw_termination_exception,
-               &throw_out_of_memory_exception,
-               false,
-               false);
-
-  // Do space-specific GC and retry runtime call.
-  GenerateCore(masm,
-               &throw_normal_exception,
-               &throw_termination_exception,
-               &throw_out_of_memory_exception,
-               true,
-               false);
-
-  // Do full GC and retry runtime call one final time.
-  Failure* failure = Failure::InternalError();
-  __ movq(rax, failure, RelocInfo::NONE);
-  GenerateCore(masm,
-               &throw_normal_exception,
-               &throw_termination_exception,
-               &throw_out_of_memory_exception,
-               true,
-               true);
-
-  __ bind(&throw_out_of_memory_exception);
-  GenerateThrowUncatchable(masm, OUT_OF_MEMORY);
-
-  __ bind(&throw_termination_exception);
-  GenerateThrowUncatchable(masm, TERMINATION);
-
-  __ bind(&throw_normal_exception);
-  GenerateThrowTOS(masm);
-}
-
-
-void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
-  Label invoke, exit;
-#ifdef ENABLE_LOGGING_AND_PROFILING
-  Label not_outermost_js, not_outermost_js_2;
-#endif
-
-  // Setup frame.
-  __ push(rbp);
-  __ movq(rbp, rsp);
-
-  // Push the stack frame type marker twice.
-  int marker = is_construct ? StackFrame::ENTRY_CONSTRUCT : StackFrame::ENTRY;
-  // Scratch register is neither callee-save, nor an argument register on any
-  // platform. It's free to use at this point.
-  // Cannot use smi-register for loading yet.
-  __ movq(kScratchRegister,
-          reinterpret_cast<uint64_t>(Smi::FromInt(marker)),
-          RelocInfo::NONE);
-  __ push(kScratchRegister);  // context slot
-  __ push(kScratchRegister);  // function slot
-  // Save callee-saved registers (X64/Win64 calling conventions).
-  __ push(r12);
-  __ push(r13);
-  __ push(r14);
-  __ push(r15);
-#ifdef _WIN64
-  __ push(rdi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
-  __ push(rsi);  // Only callee save in Win64 ABI, argument in AMD64 ABI.
-#endif
-  __ push(rbx);
-  // TODO(X64): On Win64, if we ever use XMM6-XMM15, the low low 64 bits are
-  // callee save as well.
-
-  // Save copies of the top frame descriptor on the stack.
-  ExternalReference c_entry_fp(Top::k_c_entry_fp_address);
-  __ load_rax(c_entry_fp);
-  __ push(rax);
-
-  // Set up the roots and smi constant registers.
-  // Needs to be done before any further smi loads.
-  ExternalReference roots_address = ExternalReference::roots_address();
-  __ movq(kRootRegister, roots_address);
-  __ InitializeSmiConstantRegister();
-
-#ifdef ENABLE_LOGGING_AND_PROFILING
-  // If this is the outermost JS call, set js_entry_sp value.
-  ExternalReference js_entry_sp(Top::k_js_entry_sp_address);
-  __ load_rax(js_entry_sp);
-  __ testq(rax, rax);
-  __ j(not_zero, &not_outermost_js);
-  __ movq(rax, rbp);
-  __ store_rax(js_entry_sp);
-  __ bind(&not_outermost_js);
-#endif
-
-  // Call a faked try-block that does the invoke.
-  __ call(&invoke);
-
-  // Caught exception: Store result (exception) in the pending
-  // exception field in the JSEnv and return a failure sentinel.
-  ExternalReference pending_exception(Top::k_pending_exception_address);
-  __ store_rax(pending_exception);
-  __ movq(rax, Failure::Exception(), RelocInfo::NONE);
-  __ jmp(&exit);
-
-  // Invoke: Link this frame into the handler chain.
-  __ bind(&invoke);
-  __ PushTryHandler(IN_JS_ENTRY, JS_ENTRY_HANDLER);
-
-  // Clear any pending exceptions.
-  __ load_rax(ExternalReference::the_hole_value_location());
-  __ store_rax(pending_exception);
-
-  // Fake a receiver (NULL).
-  __ push(Immediate(0));  // receiver
-
-  // Invoke the function by calling through JS entry trampoline
-  // builtin and pop the faked function when we return. We load the address
-  // from an external reference instead of inlining the call target address
-  // directly in the code, because the builtin stubs may not have been
-  // generated yet at the time this code is generated.
-  if (is_construct) {
-    ExternalReference construct_entry(Builtins::JSConstructEntryTrampoline);
-    __ load_rax(construct_entry);
-  } else {
-    ExternalReference entry(Builtins::JSEntryTrampoline);
-    __ load_rax(entry);
-  }
-  __ lea(kScratchRegister, FieldOperand(rax, Code::kHeaderSize));
-  __ call(kScratchRegister);
-
-  // Unlink this frame from the handler chain.
-  __ movq(kScratchRegister, ExternalReference(Top::k_handler_address));
-  __ pop(Operand(kScratchRegister, 0));
-  // Pop next_sp.
-  __ addq(rsp, Immediate(StackHandlerConstants::kSize - kPointerSize));
-
-#ifdef ENABLE_LOGGING_AND_PROFILING
-  // If current EBP value is the same as js_entry_sp value, it means that
-  // the current function is the outermost.
-  __ movq(kScratchRegister, js_entry_sp);
-  __ cmpq(rbp, Operand(kScratchRegister, 0));
-  __ j(not_equal, &not_outermost_js_2);
-  __ movq(Operand(kScratchRegister, 0), Immediate(0));
-  __ bind(&not_outermost_js_2);
-#endif
-
-  // Restore the top frame descriptor from the stack.
-  __ bind(&exit);
-  __ movq(kScratchRegister, ExternalReference(Top::k_c_entry_fp_address));
-  __ pop(Operand(kScratchRegister, 0));
-
-  // Restore callee-saved registers (X64 conventions).
-  __ pop(rbx);
-#ifdef _WIN64
-  // Callee save on in Win64 ABI, arguments/volatile in AMD64 ABI.
-  __ pop(rsi);
-  __ pop(rdi);
-#endif
-  __ pop(r15);
-  __ pop(r14);
-  __ pop(r13);
-  __ pop(r12);
-  __ addq(rsp, Immediate(2 * kPointerSize));  // remove markers
-
-  // Restore frame pointer and return.
-  __ pop(rbp);
-  __ ret(0);
-}
-
-
-void InstanceofStub::Generate(MacroAssembler* masm) {
-  // Implements "value instanceof function" operator.
-  // Expected input state:
-  //   rsp[0] : return address
-  //   rsp[1] : function pointer
-  //   rsp[2] : value
-  // Returns a bitwise zero to indicate that the value
-  // is and instance of the function and anything else to
-  // indicate that the value is not an instance.
-
-  // Get the object - go slow case if it's a smi.
-  Label slow;
-  __ movq(rax, Operand(rsp, 2 * kPointerSize));
-  __ JumpIfSmi(rax, &slow);
-
-  // Check that the left hand is a JS object. Leave its map in rax.
-  __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rax);
-  __ j(below, &slow);
-  __ CmpInstanceType(rax, LAST_JS_OBJECT_TYPE);
-  __ j(above, &slow);
-
-  // Get the prototype of the function.
-  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
-  // rdx is function, rax is map.
-
-  // Look up the function and the map in the instanceof cache.
-  Label miss;
-  __ CompareRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
-  __ j(not_equal, &miss);
-  __ CompareRoot(rax, Heap::kInstanceofCacheMapRootIndex);
-  __ j(not_equal, &miss);
-  __ LoadRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
-
-  __ bind(&miss);
-  __ TryGetFunctionPrototype(rdx, rbx, &slow);
-
-  // Check that the function prototype is a JS object.
-  __ JumpIfSmi(rbx, &slow);
-  __ CmpObjectType(rbx, FIRST_JS_OBJECT_TYPE, kScratchRegister);
-  __ j(below, &slow);
-  __ CmpInstanceType(kScratchRegister, LAST_JS_OBJECT_TYPE);
-  __ j(above, &slow);
-
-  // Register mapping:
-  //   rax is object map.
-  //   rdx is function.
-  //   rbx is function prototype.
-  __ StoreRoot(rdx, Heap::kInstanceofCacheFunctionRootIndex);
-  __ StoreRoot(rax, Heap::kInstanceofCacheMapRootIndex);
-
-  __ movq(rcx, FieldOperand(rax, Map::kPrototypeOffset));
-
-  // Loop through the prototype chain looking for the function prototype.
-  Label loop, is_instance, is_not_instance;
-  __ LoadRoot(kScratchRegister, Heap::kNullValueRootIndex);
-  __ bind(&loop);
-  __ cmpq(rcx, rbx);
-  __ j(equal, &is_instance);
-  __ cmpq(rcx, kScratchRegister);
-  // The code at is_not_instance assumes that kScratchRegister contains a
-  // non-zero GCable value (the null object in this case).
-  __ j(equal, &is_not_instance);
-  __ movq(rcx, FieldOperand(rcx, HeapObject::kMapOffset));
-  __ movq(rcx, FieldOperand(rcx, Map::kPrototypeOffset));
-  __ jmp(&loop);
-
-  __ bind(&is_instance);
-  __ xorl(rax, rax);
-  // Store bitwise zero in the cache.  This is a Smi in GC terms.
-  STATIC_ASSERT(kSmiTag == 0);
-  __ StoreRoot(rax, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
-
-  __ bind(&is_not_instance);
-  // We have to store a non-zero value in the cache.
-  __ StoreRoot(kScratchRegister, Heap::kInstanceofCacheAnswerRootIndex);
-  __ ret(2 * kPointerSize);
-
-  // Slow-case: Go through the JavaScript implementation.
-  __ bind(&slow);
-  __ InvokeBuiltin(Builtins::INSTANCE_OF, JUMP_FUNCTION);
-}
-
-
-int CompareStub::MinorKey() {
-  // Encode the three parameters in a unique 16 bit value. To avoid duplicate
-  // stubs the never NaN NaN condition is only taken into account if the
-  // condition is equals.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 12));
-  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
-  return ConditionField::encode(static_cast<unsigned>(cc_))
-         | RegisterField::encode(false)    // lhs_ and rhs_ are not used
-         | StrictField::encode(strict_)
-         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
-         | IncludeNumberCompareField::encode(include_number_compare_);
-}
-
-
-// Unfortunately you have to run without snapshots to see most of these
-// names in the profile since most compare stubs end up in the snapshot.
-const char* CompareStub::GetName() {
-  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
-
-  if (name_ != NULL) return name_;
-  const int kMaxNameLength = 100;
-  name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);
-  if (name_ == NULL) return "OOM";
-
-  const char* cc_name;
-  switch (cc_) {
-    case less: cc_name = "LT"; break;
-    case greater: cc_name = "GT"; break;
-    case less_equal: cc_name = "LE"; break;
-    case greater_equal: cc_name = "GE"; break;
-    case equal: cc_name = "EQ"; break;
-    case not_equal: cc_name = "NE"; break;
-    default: cc_name = "UnknownCondition"; break;
-  }
-
-  const char* strict_name = "";
-  if (strict_ && (cc_ == equal || cc_ == not_equal)) {
-    strict_name = "_STRICT";
-  }
-
-  const char* never_nan_nan_name = "";
-  if (never_nan_nan_ && (cc_ == equal || cc_ == not_equal)) {
-    never_nan_nan_name = "_NO_NAN";
-  }
-
-  const char* include_number_compare_name = "";
-  if (!include_number_compare_) {
-    include_number_compare_name = "_NO_NUMBER";
-  }
-
-  OS::SNPrintF(Vector<char>(name_, kMaxNameLength),
-               "CompareStub_%s%s%s%s",
-               cc_name,
-               strict_name,
-               never_nan_nan_name,
-               include_number_compare_name);
-  return name_;
-}
-
-
-// -------------------------------------------------------------------------
-// StringCharCodeAtGenerator
-
-void StringCharCodeAtGenerator::GenerateFast(MacroAssembler* masm) {
-  Label flat_string;
-  Label ascii_string;
-  Label got_char_code;
-
-  // If the receiver is a smi trigger the non-string case.
-  __ JumpIfSmi(object_, receiver_not_string_);
-
-  // Fetch the instance type of the receiver into result register.
-  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
-  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
-  // If the receiver is not a string trigger the non-string case.
-  __ testb(result_, Immediate(kIsNotStringMask));
-  __ j(not_zero, receiver_not_string_);
-
-  // If the index is non-smi trigger the non-smi case.
-  __ JumpIfNotSmi(index_, &index_not_smi_);
-
-  // Put smi-tagged index into scratch register.
-  __ movq(scratch_, index_);
-  __ bind(&got_smi_index_);
-
-  // Check for index out of range.
-  __ SmiCompare(scratch_, FieldOperand(object_, String::kLengthOffset));
-  __ j(above_equal, index_out_of_range_);
-
-  // We need special handling for non-flat strings.
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(result_, Immediate(kStringRepresentationMask));
-  __ j(zero, &flat_string);
-
-  // Handle non-flat strings.
-  __ testb(result_, Immediate(kIsConsStringMask));
-  __ j(zero, &call_runtime_);
-
-  // ConsString.
-  // Check whether the right hand side is the empty string (i.e. if
-  // this is really a flat string in a cons string). If that is not
-  // the case we would rather go to the runtime system now to flatten
-  // the string.
-  __ CompareRoot(FieldOperand(object_, ConsString::kSecondOffset),
-                 Heap::kEmptyStringRootIndex);
-  __ j(not_equal, &call_runtime_);
-  // Get the first of the two strings and load its instance type.
-  __ movq(object_, FieldOperand(object_, ConsString::kFirstOffset));
-  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
-  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
-  // If the first cons component is also non-flat, then go to runtime.
-  STATIC_ASSERT(kSeqStringTag == 0);
-  __ testb(result_, Immediate(kStringRepresentationMask));
-  __ j(not_zero, &call_runtime_);
-
-  // Check for 1-byte or 2-byte string.
-  __ bind(&flat_string);
-  STATIC_ASSERT(kAsciiStringTag != 0);
-  __ testb(result_, Immediate(kStringEncodingMask));
-  __ j(not_zero, &ascii_string);
-
-  // 2-byte string.
-  // Load the 2-byte character code into the result register.
-  __ SmiToInteger32(scratch_, scratch_);
-  __ movzxwl(result_, FieldOperand(object_,
-                                   scratch_, times_2,
-                                   SeqTwoByteString::kHeaderSize));
-  __ jmp(&got_char_code);
-
-  // ASCII string.
-  // Load the byte into the result register.
-  __ bind(&ascii_string);
-  __ SmiToInteger32(scratch_, scratch_);
-  __ movzxbl(result_, FieldOperand(object_,
-                                   scratch_, times_1,
-                                   SeqAsciiString::kHeaderSize));
-  __ bind(&got_char_code);
-  __ Integer32ToSmi(result_, result_);
-  __ bind(&exit_);
-}
-
-
-void StringCharCodeAtGenerator::GenerateSlow(
-    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
-  __ Abort("Unexpected fallthrough to CharCodeAt slow case");
-
-  // Index is not a smi.
-  __ bind(&index_not_smi_);
-  // If index is a heap number, try converting it to an integer.
-  __ CheckMap(index_, Factory::heap_number_map(), index_not_number_, true);
-  call_helper.BeforeCall(masm);
-  __ push(object_);
-  __ push(index_);
-  __ push(index_);  // Consumed by runtime conversion function.
-  if (index_flags_ == STRING_INDEX_IS_NUMBER) {
-    __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero, 1);
-  } else {
-    ASSERT(index_flags_ == STRING_INDEX_IS_ARRAY_INDEX);
-    // NumberToSmi discards numbers that are not exact integers.
-    __ CallRuntime(Runtime::kNumberToSmi, 1);
-  }
-  if (!scratch_.is(rax)) {
-    // Save the conversion result before the pop instructions below
-    // have a chance to overwrite it.
-    __ movq(scratch_, rax);
-  }
-  __ pop(index_);
-  __ pop(object_);
-  // Reload the instance type.
-  __ movq(result_, FieldOperand(object_, HeapObject::kMapOffset));
-  __ movzxbl(result_, FieldOperand(result_, Map::kInstanceTypeOffset));
-  call_helper.AfterCall(masm);
-  // If index is still not a smi, it must be out of range.
-  __ JumpIfNotSmi(scratch_, index_out_of_range_);
-  // Otherwise, return to the fast path.
-  __ jmp(&got_smi_index_);
-
-  // Call runtime. We get here when the receiver is a string and the
-  // index is a number, but the code of getting the actual character
-  // is too complex (e.g., when the string needs to be flattened).
-  __ bind(&call_runtime_);
-  call_helper.BeforeCall(masm);
-  __ push(object_);
-  __ push(index_);
-  __ CallRuntime(Runtime::kStringCharCodeAt, 2);
-  if (!result_.is(rax)) {
-    __ movq(result_, rax);
-  }
-  call_helper.AfterCall(masm);
-  __ jmp(&exit_);
-
-  __ Abort("Unexpected fallthrough from CharCodeAt slow case");
-}
-
-
-// -------------------------------------------------------------------------
-// StringCharFromCodeGenerator
-
-void StringCharFromCodeGenerator::GenerateFast(MacroAssembler* masm) {
-  // Fast case of Heap::LookupSingleCharacterStringFromCode.
-  __ JumpIfNotSmi(code_, &slow_case_);
-  __ SmiCompare(code_, Smi::FromInt(String::kMaxAsciiCharCode));
-  __ j(above, &slow_case_);
-
-  __ LoadRoot(result_, Heap::kSingleCharacterStringCacheRootIndex);
-  SmiIndex index = masm->SmiToIndex(kScratchRegister, code_, kPointerSizeLog2);
-  __ movq(result_, FieldOperand(result_, index.reg, index.scale,
-                                FixedArray::kHeaderSize));
-  __ CompareRoot(result_, Heap::kUndefinedValueRootIndex);
-  __ j(equal, &slow_case_);
-  __ bind(&exit_);
-}
-
-
-void StringCharFromCodeGenerator::GenerateSlow(
-    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
-  __ Abort("Unexpected fallthrough to CharFromCode slow case");
-
-  __ bind(&slow_case_);
-  call_helper.BeforeCall(masm);
-  __ push(code_);
-  __ CallRuntime(Runtime::kCharFromCode, 1);
-  if (!result_.is(rax)) {
-    __ movq(result_, rax);
-  }
-  call_helper.AfterCall(masm);
-  __ jmp(&exit_);
-
-  __ Abort("Unexpected fallthrough from CharFromCode slow case");
-}
-
-
-// -------------------------------------------------------------------------
-// StringCharAtGenerator
-
-void StringCharAtGenerator::GenerateFast(MacroAssembler* masm) {
-  char_code_at_generator_.GenerateFast(masm);
-  char_from_code_generator_.GenerateFast(masm);
-}
-
-
-void StringCharAtGenerator::GenerateSlow(
-    MacroAssembler* masm, const RuntimeCallHelper& call_helper) {
-  char_code_at_generator_.GenerateSlow(masm, call_helper);
-  char_from_code_generator_.GenerateSlow(masm, call_helper);
-}
-
-
-void StringAddStub::Generate(MacroAssembler* masm) {
-  Label string_add_runtime;
-
-  // Load the two arguments.
-  __ movq(rax, Operand(rsp, 2 * kPointerSize));  // First argument.
-  __ movq(rdx, Operand(rsp, 1 * kPointerSize));  // Second argument.
-
-  // Make sure that both arguments are strings if not known in advance.
-  if (string_check_) {
-    Condition is_smi;
-    is_smi = masm->CheckSmi(rax);
-    __ j(is_smi, &string_add_runtime);
-    __ CmpObjectType(rax, FIRST_NONSTRING_TYPE, r8);
-    __ j(above_equal, &string_add_runtime);
-
-    // First argument is a a string, test second.
-    is_smi = masm->CheckSmi(rdx);
-    __ j(is_smi, &string_add_runtime);
-    __ CmpObjectType(rdx, FIRST_NONSTRING_TYPE, r9);
-    __ j(above_equal, &string_add_runtime);
-  }
-
-  // Both arguments are strings.
-  // rax: first string
-  // rdx: second string
-  // Check if either of the strings are empty. In that case return the other.
-  Label second_not_zero_length, both_not_zero_length;
-  __ movq(rcx, FieldOperand(rdx, String::kLengthOffset));
-  __ SmiTest(rcx);
-  __ j(not_zero, &second_not_zero_length);
-  // Second string is empty, result is first string which is already in rax.
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-  __ bind(&second_not_zero_length);
-  __ movq(rbx, FieldOperand(rax, String::kLengthOffset));
-  __ SmiTest(rbx);
-  __ j(not_zero, &both_not_zero_length);
-  // First string is empty, result is second string which is in rdx.
-  __ movq(rax, rdx);
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-
-  // Both strings are non-empty.
-  // rax: first string
-  // rbx: length of first string
-  // rcx: length of second string
-  // rdx: second string
-  // r8: map of first string if string check was performed above
-  // r9: map of second string if string check was performed above
-  Label string_add_flat_result, longer_than_two;
-  __ bind(&both_not_zero_length);
-
-  // If arguments where known to be strings, maps are not loaded to r8 and r9
-  // by the code above.
-  if (!string_check_) {
-    __ movq(r8, FieldOperand(rax, HeapObject::kMapOffset));
-    __ movq(r9, FieldOperand(rdx, HeapObject::kMapOffset));
-  }
-  // Get the instance types of the two strings as they will be needed soon.
-  __ movzxbl(r8, FieldOperand(r8, Map::kInstanceTypeOffset));
-  __ movzxbl(r9, FieldOperand(r9, Map::kInstanceTypeOffset));
-
-  // Look at the length of the result of adding the two strings.
-  STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue / 2);
-  __ SmiAdd(rbx, rbx, rcx, NULL);
-  // Use the runtime system when adding two one character strings, as it
-  // contains optimizations for this specific case using the symbol table.
-  __ SmiCompare(rbx, Smi::FromInt(2));
-  __ j(not_equal, &longer_than_two);
-
-  // Check that both strings are non-external ascii strings.
-  __ JumpIfBothInstanceTypesAreNotSequentialAscii(r8, r9, rbx, rcx,
-                                                  &string_add_runtime);
-
-  // Get the two characters forming the sub string.
-  __ movzxbq(rbx, FieldOperand(rax, SeqAsciiString::kHeaderSize));
-  __ movzxbq(rcx, FieldOperand(rdx, SeqAsciiString::kHeaderSize));
-
-  // Try to lookup two character string in symbol table. If it is not found
-  // just allocate a new one.
-  Label make_two_character_string, make_flat_ascii_string;
-  StringHelper::GenerateTwoCharacterSymbolTableProbe(
-      masm, rbx, rcx, r14, r11, rdi, r12, &make_two_character_string);
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-
-  __ bind(&make_two_character_string);
-  __ Set(rbx, 2);
-  __ jmp(&make_flat_ascii_string);
-
-  __ bind(&longer_than_two);
-  // Check if resulting string will be flat.
-  __ SmiCompare(rbx, Smi::FromInt(String::kMinNonFlatLength));
-  __ j(below, &string_add_flat_result);
-  // Handle exceptionally long strings in the runtime system.
-  STATIC_ASSERT((String::kMaxLength & 0x80000000) == 0);
-  __ SmiCompare(rbx, Smi::FromInt(String::kMaxLength));
-  __ j(above, &string_add_runtime);
-
-  // If result is not supposed to be flat, allocate a cons string object. If
-  // both strings are ascii the result is an ascii cons string.
-  // rax: first string
-  // rbx: length of resulting flat string
-  // rdx: second string
-  // r8: instance type of first string
-  // r9: instance type of second string
-  Label non_ascii, allocated, ascii_data;
-  __ movl(rcx, r8);
-  __ and_(rcx, r9);
-  STATIC_ASSERT(kStringEncodingMask == kAsciiStringTag);
-  __ testl(rcx, Immediate(kAsciiStringTag));
-  __ j(zero, &non_ascii);
-  __ bind(&ascii_data);
-  // Allocate an acsii cons string.
-  __ AllocateAsciiConsString(rcx, rdi, no_reg, &string_add_runtime);
-  __ bind(&allocated);
-  // Fill the fields of the cons string.
-  __ movq(FieldOperand(rcx, ConsString::kLengthOffset), rbx);
-  __ movq(FieldOperand(rcx, ConsString::kHashFieldOffset),
-          Immediate(String::kEmptyHashField));
-  __ movq(FieldOperand(rcx, ConsString::kFirstOffset), rax);
-  __ movq(FieldOperand(rcx, ConsString::kSecondOffset), rdx);
-  __ movq(rax, rcx);
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-  __ bind(&non_ascii);
-  // At least one of the strings is two-byte. Check whether it happens
-  // to contain only ascii characters.
-  // rcx: first instance type AND second instance type.
-  // r8: first instance type.
-  // r9: second instance type.
-  __ testb(rcx, Immediate(kAsciiDataHintMask));
-  __ j(not_zero, &ascii_data);
-  __ xor_(r8, r9);
-  STATIC_ASSERT(kAsciiStringTag != 0 && kAsciiDataHintTag != 0);
-  __ andb(r8, Immediate(kAsciiStringTag | kAsciiDataHintTag));
-  __ cmpb(r8, Immediate(kAsciiStringTag | kAsciiDataHintTag));
-  __ j(equal, &ascii_data);
-  // Allocate a two byte cons string.
-  __ AllocateConsString(rcx, rdi, no_reg, &string_add_runtime);
-  __ jmp(&allocated);
-
-  // Handle creating a flat result. First check that both strings are not
-  // external strings.
-  // rax: first string
-  // rbx: length of resulting flat string as smi
-  // rdx: second string
-  // r8: instance type of first string
-  // r9: instance type of first string
-  __ bind(&string_add_flat_result);
-  __ SmiToInteger32(rbx, rbx);
-  __ movl(rcx, r8);
-  __ and_(rcx, Immediate(kStringRepresentationMask));
-  __ cmpl(rcx, Immediate(kExternalStringTag));
-  __ j(equal, &string_add_runtime);
-  __ movl(rcx, r9);
-  __ and_(rcx, Immediate(kStringRepresentationMask));
-  __ cmpl(rcx, Immediate(kExternalStringTag));
-  __ j(equal, &string_add_runtime);
-  // Now check if both strings are ascii strings.
-  // rax: first string
-  // rbx: length of resulting flat string
-  // rdx: second string
-  // r8: instance type of first string
-  // r9: instance type of second string
-  Label non_ascii_string_add_flat_result;
-  STATIC_ASSERT(kStringEncodingMask == kAsciiStringTag);
-  __ testl(r8, Immediate(kAsciiStringTag));
-  __ j(zero, &non_ascii_string_add_flat_result);
-  __ testl(r9, Immediate(kAsciiStringTag));
-  __ j(zero, &string_add_runtime);
-
-  __ bind(&make_flat_ascii_string);
-  // Both strings are ascii strings. As they are short they are both flat.
-  __ AllocateAsciiString(rcx, rbx, rdi, r14, r11, &string_add_runtime);
-  // rcx: result string
-  __ movq(rbx, rcx);
-  // Locate first character of result.
-  __ addq(rcx, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  // Locate first character of first argument
-  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
-  __ addq(rax, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  // rax: first char of first argument
-  // rbx: result string
-  // rcx: first character of result
-  // rdx: second string
-  // rdi: length of first argument
-  StringHelper::GenerateCopyCharacters(masm, rcx, rax, rdi, true);
-  // Locate first character of second argument.
-  __ SmiToInteger32(rdi, FieldOperand(rdx, String::kLengthOffset));
-  __ addq(rdx, Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  // rbx: result string
-  // rcx: next character of result
-  // rdx: first char of second argument
-  // rdi: length of second argument
-  StringHelper::GenerateCopyCharacters(masm, rcx, rdx, rdi, true);
-  __ movq(rax, rbx);
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-
-  // Handle creating a flat two byte result.
-  // rax: first string - known to be two byte
-  // rbx: length of resulting flat string
-  // rdx: second string
-  // r8: instance type of first string
-  // r9: instance type of first string
-  __ bind(&non_ascii_string_add_flat_result);
-  __ and_(r9, Immediate(kAsciiStringTag));
-  __ j(not_zero, &string_add_runtime);
-  // Both strings are two byte strings. As they are short they are both
-  // flat.
-  __ AllocateTwoByteString(rcx, rbx, rdi, r14, r11, &string_add_runtime);
-  // rcx: result string
-  __ movq(rbx, rcx);
-  // Locate first character of result.
-  __ addq(rcx, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  // Locate first character of first argument.
-  __ SmiToInteger32(rdi, FieldOperand(rax, String::kLengthOffset));
-  __ addq(rax, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  // rax: first char of first argument
-  // rbx: result string
-  // rcx: first character of result
-  // rdx: second argument
-  // rdi: length of first argument
-  StringHelper::GenerateCopyCharacters(masm, rcx, rax, rdi, false);
-  // Locate first character of second argument.
-  __ SmiToInteger32(rdi, FieldOperand(rdx, String::kLengthOffset));
-  __ addq(rdx, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  // rbx: result string
-  // rcx: next character of result
-  // rdx: first char of second argument
-  // rdi: length of second argument
-  StringHelper::GenerateCopyCharacters(masm, rcx, rdx, rdi, false);
-  __ movq(rax, rbx);
-  __ IncrementCounter(&Counters::string_add_native, 1);
-  __ ret(2 * kPointerSize);
-
-  // Just jump to runtime to add the two strings.
-  __ bind(&string_add_runtime);
-  __ TailCallRuntime(Runtime::kStringAdd, 2, 1);
-}
-
-
-void StringHelper::GenerateCopyCharacters(MacroAssembler* masm,
-                                          Register dest,
-                                          Register src,
-                                          Register count,
-                                          bool ascii) {
-  Label loop;
-  __ bind(&loop);
-  // This loop just copies one character at a time, as it is only used for very
-  // short strings.
-  if (ascii) {
-    __ movb(kScratchRegister, Operand(src, 0));
-    __ movb(Operand(dest, 0), kScratchRegister);
-    __ incq(src);
-    __ incq(dest);
-  } else {
-    __ movzxwl(kScratchRegister, Operand(src, 0));
-    __ movw(Operand(dest, 0), kScratchRegister);
-    __ addq(src, Immediate(2));
-    __ addq(dest, Immediate(2));
-  }
-  __ decl(count);
-  __ j(not_zero, &loop);
-}
-
-
-void StringHelper::GenerateCopyCharactersREP(MacroAssembler* masm,
-                                             Register dest,
-                                             Register src,
-                                             Register count,
-                                             bool ascii) {
-  // Copy characters using rep movs of doublewords. Align destination on 4 byte
-  // boundary before starting rep movs. Copy remaining characters after running
-  // rep movs.
-  // Count is positive int32, dest and src are character pointers.
-  ASSERT(dest.is(rdi));  // rep movs destination
-  ASSERT(src.is(rsi));  // rep movs source
-  ASSERT(count.is(rcx));  // rep movs count
-
-  // Nothing to do for zero characters.
-  Label done;
-  __ testl(count, count);
-  __ j(zero, &done);
-
-  // Make count the number of bytes to copy.
-  if (!ascii) {
-    STATIC_ASSERT(2 == sizeof(uc16));
-    __ addl(count, count);
-  }
-
-  // Don't enter the rep movs if there are less than 4 bytes to copy.
-  Label last_bytes;
-  __ testl(count, Immediate(~7));
-  __ j(zero, &last_bytes);
-
-  // Copy from edi to esi using rep movs instruction.
-  __ movl(kScratchRegister, count);
-  __ shr(count, Immediate(3));  // Number of doublewords to copy.
-  __ repmovsq();
-
-  // Find number of bytes left.
-  __ movl(count, kScratchRegister);
-  __ and_(count, Immediate(7));
-
-  // Check if there are more bytes to copy.
-  __ bind(&last_bytes);
-  __ testl(count, count);
-  __ j(zero, &done);
-
-  // Copy remaining characters.
-  Label loop;
-  __ bind(&loop);
-  __ movb(kScratchRegister, Operand(src, 0));
-  __ movb(Operand(dest, 0), kScratchRegister);
-  __ incq(src);
-  __ incq(dest);
-  __ decl(count);
-  __ j(not_zero, &loop);
-
-  __ bind(&done);
-}
-
-void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
-                                                        Register c1,
-                                                        Register c2,
-                                                        Register scratch1,
-                                                        Register scratch2,
-                                                        Register scratch3,
-                                                        Register scratch4,
-                                                        Label* not_found) {
-  // Register scratch3 is the general scratch register in this function.
-  Register scratch = scratch3;
-
-  // Make sure that both characters are not digits as such strings has a
-  // different hash algorithm. Don't try to look for these in the symbol table.
-  Label not_array_index;
-  __ leal(scratch, Operand(c1, -'0'));
-  __ cmpl(scratch, Immediate(static_cast<int>('9' - '0')));
-  __ j(above, &not_array_index);
-  __ leal(scratch, Operand(c2, -'0'));
-  __ cmpl(scratch, Immediate(static_cast<int>('9' - '0')));
-  __ j(below_equal, not_found);
-
-  __ bind(&not_array_index);
-  // Calculate the two character string hash.
-  Register hash = scratch1;
-  GenerateHashInit(masm, hash, c1, scratch);
-  GenerateHashAddCharacter(masm, hash, c2, scratch);
-  GenerateHashGetHash(masm, hash, scratch);
-
-  // Collect the two characters in a register.
-  Register chars = c1;
-  __ shl(c2, Immediate(kBitsPerByte));
-  __ orl(chars, c2);
-
-  // chars: two character string, char 1 in byte 0 and char 2 in byte 1.
-  // hash:  hash of two character string.
-
-  // Load the symbol table.
-  Register symbol_table = c2;
-  __ LoadRoot(symbol_table, Heap::kSymbolTableRootIndex);
-
-  // Calculate capacity mask from the symbol table capacity.
-  Register mask = scratch2;
-  __ SmiToInteger32(mask,
-                    FieldOperand(symbol_table, SymbolTable::kCapacityOffset));
-  __ decl(mask);
-
-  Register undefined = scratch4;
-  __ LoadRoot(undefined, Heap::kUndefinedValueRootIndex);
-
-  // Registers
-  // chars:        two character string, char 1 in byte 0 and char 2 in byte 1.
-  // hash:         hash of two character string (32-bit int)
-  // symbol_table: symbol table
-  // mask:         capacity mask (32-bit int)
-  // undefined:    undefined value
-  // scratch:      -
-
-  // Perform a number of probes in the symbol table.
-  static const int kProbes = 4;
-  Label found_in_symbol_table;
-  Label next_probe[kProbes];
-  for (int i = 0; i < kProbes; i++) {
-    // Calculate entry in symbol table.
-    __ movl(scratch, hash);
-    if (i > 0) {
-      __ addl(scratch, Immediate(SymbolTable::GetProbeOffset(i)));
-    }
-    __ andl(scratch, mask);
-
-    // Load the entry from the symble table.
-    Register candidate = scratch;  // Scratch register contains candidate.
-    STATIC_ASSERT(SymbolTable::kEntrySize == 1);
-    __ movq(candidate,
-            FieldOperand(symbol_table,
-                         scratch,
-                         times_pointer_size,
-                         SymbolTable::kElementsStartOffset));
-
-    // If entry is undefined no string with this hash can be found.
-    __ cmpq(candidate, undefined);
-    __ j(equal, not_found);
-
-    // If length is not 2 the string is not a candidate.
-    __ SmiCompare(FieldOperand(candidate, String::kLengthOffset),
-                  Smi::FromInt(2));
-    __ j(not_equal, &next_probe[i]);
-
-    // We use kScratchRegister as a temporary register in assumption that
-    // JumpIfInstanceTypeIsNotSequentialAscii does not use it implicitly
-    Register temp = kScratchRegister;
-
-    // Check that the candidate is a non-external ascii string.
-    __ movq(temp, FieldOperand(candidate, HeapObject::kMapOffset));
-    __ movzxbl(temp, FieldOperand(temp, Map::kInstanceTypeOffset));
-    __ JumpIfInstanceTypeIsNotSequentialAscii(
-        temp, temp, &next_probe[i]);
-
-    // Check if the two characters match.
-    __ movl(temp, FieldOperand(candidate, SeqAsciiString::kHeaderSize));
-    __ andl(temp, Immediate(0x0000ffff));
-    __ cmpl(chars, temp);
-    __ j(equal, &found_in_symbol_table);
-    __ bind(&next_probe[i]);
-  }
-
-  // No matching 2 character string found by probing.
-  __ jmp(not_found);
-
-  // Scratch register contains result when we fall through to here.
-  Register result = scratch;
-  __ bind(&found_in_symbol_table);
-  if (!result.is(rax)) {
-    __ movq(rax, result);
-  }
-}
-
-
-void StringHelper::GenerateHashInit(MacroAssembler* masm,
-                                    Register hash,
-                                    Register character,
-                                    Register scratch) {
-  // hash = character + (character << 10);
-  __ movl(hash, character);
-  __ shll(hash, Immediate(10));
-  __ addl(hash, character);
-  // hash ^= hash >> 6;
-  __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(6));
-  __ xorl(hash, scratch);
-}
-
-
-void StringHelper::GenerateHashAddCharacter(MacroAssembler* masm,
-                                            Register hash,
-                                            Register character,
-                                            Register scratch) {
-  // hash += character;
-  __ addl(hash, character);
-  // hash += hash << 10;
-  __ movl(scratch, hash);
-  __ shll(scratch, Immediate(10));
-  __ addl(hash, scratch);
-  // hash ^= hash >> 6;
-  __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(6));
-  __ xorl(hash, scratch);
-}
-
-
-void StringHelper::GenerateHashGetHash(MacroAssembler* masm,
-                                       Register hash,
-                                       Register scratch) {
-  // hash += hash << 3;
-  __ leal(hash, Operand(hash, hash, times_8, 0));
-  // hash ^= hash >> 11;
-  __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(11));
-  __ xorl(hash, scratch);
-  // hash += hash << 15;
-  __ movl(scratch, hash);
-  __ shll(scratch, Immediate(15));
-  __ addl(hash, scratch);
-
-  // if (hash == 0) hash = 27;
-  Label hash_not_zero;
-  __ j(not_zero, &hash_not_zero);
-  __ movl(hash, Immediate(27));
-  __ bind(&hash_not_zero);
-}
-
-void SubStringStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  // Stack frame on entry.
-  //  rsp[0]: return address
-  //  rsp[8]: to
-  //  rsp[16]: from
-  //  rsp[24]: string
-
-  const int kToOffset = 1 * kPointerSize;
-  const int kFromOffset = kToOffset + kPointerSize;
-  const int kStringOffset = kFromOffset + kPointerSize;
-  const int kArgumentsSize = (kStringOffset + kPointerSize) - kToOffset;
-
-  // Make sure first argument is a string.
-  __ movq(rax, Operand(rsp, kStringOffset));
-  STATIC_ASSERT(kSmiTag == 0);
-  __ testl(rax, Immediate(kSmiTagMask));
-  __ j(zero, &runtime);
-  Condition is_string = masm->IsObjectStringType(rax, rbx, rbx);
-  __ j(NegateCondition(is_string), &runtime);
-
-  // rax: string
-  // rbx: instance type
-  // Calculate length of sub string using the smi values.
-  Label result_longer_than_two;
-  __ movq(rcx, Operand(rsp, kToOffset));
-  __ movq(rdx, Operand(rsp, kFromOffset));
-  __ JumpIfNotBothPositiveSmi(rcx, rdx, &runtime);
-
-  __ SmiSub(rcx, rcx, rdx, NULL);  // Overflow doesn't happen.
-  __ cmpq(FieldOperand(rax, String::kLengthOffset), rcx);
-  Label return_rax;
-  __ j(equal, &return_rax);
-  // Special handling of sub-strings of length 1 and 2. One character strings
-  // are handled in the runtime system (looked up in the single character
-  // cache). Two character strings are looked for in the symbol cache.
-  __ SmiToInteger32(rcx, rcx);
-  __ cmpl(rcx, Immediate(2));
-  __ j(greater, &result_longer_than_two);
-  __ j(less, &runtime);
-
-  // Sub string of length 2 requested.
-  // rax: string
-  // rbx: instance type
-  // rcx: sub string length (value is 2)
-  // rdx: from index (smi)
-  __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &runtime);
-
-  // Get the two characters forming the sub string.
-  __ SmiToInteger32(rdx, rdx);  // From index is no longer smi.
-  __ movzxbq(rbx, FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize));
-  __ movzxbq(rcx,
-             FieldOperand(rax, rdx, times_1, SeqAsciiString::kHeaderSize + 1));
-
-  // Try to lookup two character string in symbol table.
-  Label make_two_character_string;
-  StringHelper::GenerateTwoCharacterSymbolTableProbe(
-      masm, rbx, rcx, rax, rdx, rdi, r14, &make_two_character_string);
-  __ ret(3 * kPointerSize);
-
-  __ bind(&make_two_character_string);
-  // Setup registers for allocating the two character string.
-  __ movq(rax, Operand(rsp, kStringOffset));
-  __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
-  __ movzxbl(rbx, FieldOperand(rbx, Map::kInstanceTypeOffset));
-  __ Set(rcx, 2);
-
-  __ bind(&result_longer_than_two);
-
-  // rax: string
-  // rbx: instance type
-  // rcx: result string length
-  // Check for flat ascii string
-  Label non_ascii_flat;
-  __ JumpIfInstanceTypeIsNotSequentialAscii(rbx, rbx, &non_ascii_flat);
-
-  // Allocate the result.
-  __ AllocateAsciiString(rax, rcx, rbx, rdx, rdi, &runtime);
-
-  // rax: result string
-  // rcx: result string length
-  __ movq(rdx, rsi);  // esi used by following code.
-  // Locate first character of result.
-  __ lea(rdi, FieldOperand(rax, SeqAsciiString::kHeaderSize));
-  // Load string argument and locate character of sub string start.
-  __ movq(rsi, Operand(rsp, kStringOffset));
-  __ movq(rbx, Operand(rsp, kFromOffset));
-  {
-    SmiIndex smi_as_index = masm->SmiToIndex(rbx, rbx, times_1);
-    __ lea(rsi, Operand(rsi, smi_as_index.reg, smi_as_index.scale,
-                        SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  }
-
-  // rax: result string
-  // rcx: result length
-  // rdx: original value of rsi
-  // rdi: first character of result
-  // rsi: character of sub string start
-  StringHelper::GenerateCopyCharactersREP(masm, rdi, rsi, rcx, true);
-  __ movq(rsi, rdx);  // Restore rsi.
-  __ IncrementCounter(&Counters::sub_string_native, 1);
-  __ ret(kArgumentsSize);
-
-  __ bind(&non_ascii_flat);
-  // rax: string
-  // rbx: instance type & kStringRepresentationMask | kStringEncodingMask
-  // rcx: result string length
-  // Check for sequential two byte string
-  __ cmpb(rbx, Immediate(kSeqStringTag | kTwoByteStringTag));
-  __ j(not_equal, &runtime);
-
-  // Allocate the result.
-  __ AllocateTwoByteString(rax, rcx, rbx, rdx, rdi, &runtime);
-
-  // rax: result string
-  // rcx: result string length
-  __ movq(rdx, rsi);  // esi used by following code.
-  // Locate first character of result.
-  __ lea(rdi, FieldOperand(rax, SeqTwoByteString::kHeaderSize));
-  // Load string argument and locate character of sub string start.
-  __ movq(rsi, Operand(rsp, kStringOffset));
-  __ movq(rbx, Operand(rsp, kFromOffset));
-  {
-    SmiIndex smi_as_index = masm->SmiToIndex(rbx, rbx, times_2);
-    __ lea(rsi, Operand(rsi, smi_as_index.reg, smi_as_index.scale,
-                        SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  }
-
-  // rax: result string
-  // rcx: result length
-  // rdx: original value of rsi
-  // rdi: first character of result
-  // rsi: character of sub string start
-  StringHelper::GenerateCopyCharactersREP(masm, rdi, rsi, rcx, false);
-  __ movq(rsi, rdx);  // Restore esi.
-
-  __ bind(&return_rax);
-  __ IncrementCounter(&Counters::sub_string_native, 1);
-  __ ret(kArgumentsSize);
-
-  // Just jump to runtime to create the sub string.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kSubString, 3, 1);
-}
-
-
-void StringCompareStub::GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
-                                                        Register left,
-                                                        Register right,
-                                                        Register scratch1,
-                                                        Register scratch2,
-                                                        Register scratch3,
-                                                        Register scratch4) {
-  // Ensure that you can always subtract a string length from a non-negative
-  // number (e.g. another length).
-  STATIC_ASSERT(String::kMaxLength < 0x7fffffff);
-
-  // Find minimum length and length difference.
-  __ movq(scratch1, FieldOperand(left, String::kLengthOffset));
-  __ movq(scratch4, scratch1);
-  __ SmiSub(scratch4,
-            scratch4,
-            FieldOperand(right, String::kLengthOffset),
-            NULL);
-  // Register scratch4 now holds left.length - right.length.
-  const Register length_difference = scratch4;
-  Label left_shorter;
-  __ j(less, &left_shorter);
-  // The right string isn't longer that the left one.
-  // Get the right string's length by subtracting the (non-negative) difference
-  // from the left string's length.
-  __ SmiSub(scratch1, scratch1, length_difference, NULL);
-  __ bind(&left_shorter);
-  // Register scratch1 now holds Min(left.length, right.length).
-  const Register min_length = scratch1;
-
-  Label compare_lengths;
-  // If min-length is zero, go directly to comparing lengths.
-  __ SmiTest(min_length);
-  __ j(zero, &compare_lengths);
-
-  __ SmiToInteger32(min_length, min_length);
-
-  // Registers scratch2 and scratch3 are free.
-  Label result_not_equal;
-  Label loop;
-  {
-    // Check characters 0 .. min_length - 1 in a loop.
-    // Use scratch3 as loop index, min_length as limit and scratch2
-    // for computation.
-    const Register index = scratch3;
-    __ movl(index, Immediate(0));  // Index into strings.
-    __ bind(&loop);
-    // Compare characters.
-    // TODO(lrn): Could we load more than one character at a time?
-    __ movb(scratch2, FieldOperand(left,
-                                   index,
-                                   times_1,
-                                   SeqAsciiString::kHeaderSize));
-    // Increment index and use -1 modifier on next load to give
-    // the previous load extra time to complete.
-    __ addl(index, Immediate(1));
-    __ cmpb(scratch2, FieldOperand(right,
-                                   index,
-                                   times_1,
-                                   SeqAsciiString::kHeaderSize - 1));
-    __ j(not_equal, &result_not_equal);
-    __ cmpl(index, min_length);
-    __ j(not_equal, &loop);
+    frame_->Push(left);
+    frame_->Push(right);
+    return frame_->CallStub(stub, 2);
   }
-  // Completed loop without finding different characters.
-  // Compare lengths (precomputed).
-  __ bind(&compare_lengths);
-  __ SmiTest(length_difference);
-  __ j(not_zero, &result_not_equal);
-
-  // Result is EQUAL.
-  __ Move(rax, Smi::FromInt(EQUAL));
-  __ ret(0);
-
-  Label result_greater;
-  __ bind(&result_not_equal);
-  // Unequal comparison of left to right, either character or length.
-  __ j(greater, &result_greater);
-
-  // Result is LESS.
-  __ Move(rax, Smi::FromInt(LESS));
-  __ ret(0);
-
-  // Result is GREATER.
-  __ bind(&result_greater);
-  __ Move(rax, Smi::FromInt(GREATER));
-  __ ret(0);
-}
-
-
-void StringCompareStub::Generate(MacroAssembler* masm) {
-  Label runtime;
-
-  // Stack frame on entry.
-  //  rsp[0]: return address
-  //  rsp[8]: right string
-  //  rsp[16]: left string
-
-  __ movq(rdx, Operand(rsp, 2 * kPointerSize));  // left
-  __ movq(rax, Operand(rsp, 1 * kPointerSize));  // right
-
-  // Check for identity.
-  Label not_same;
-  __ cmpq(rdx, rax);
-  __ j(not_equal, &not_same);
-  __ Move(rax, Smi::FromInt(EQUAL));
-  __ IncrementCounter(&Counters::string_compare_native, 1);
-  __ ret(2 * kPointerSize);
-
-  __ bind(&not_same);
-
-  // Check that both are sequential ASCII strings.
-  __ JumpIfNotBothSequentialAsciiStrings(rdx, rax, rcx, rbx, &runtime);
-
-  // Inline comparison of ascii strings.
-  __ IncrementCounter(&Counters::string_compare_native, 1);
-  // Drop arguments from the stack
-  __ pop(rcx);
-  __ addq(rsp, Immediate(2 * kPointerSize));
-  __ push(rcx);
-  GenerateCompareFlatAsciiStrings(masm, rdx, rax, rcx, rbx, rdi, r8);
-
-  // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
-  // tagged as a small integer.
-  __ bind(&runtime);
-  __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
 }
 
 #undef __
diff --git a/deps/v8/src/x64/codegen-x64.h b/deps/v8/src/x64/codegen-x64.h
index 14f690eb81..07bdadf9a1 100644
--- a/deps/v8/src/x64/codegen-x64.h
+++ b/deps/v8/src/x64/codegen-x64.h
@@ -492,6 +492,11 @@ class CodeGenerator: public AstVisitor {
   void GenericBinaryOperation(BinaryOperation* expr,
                               OverwriteMode overwrite_mode);
 
+  // Generate a stub call from the virtual frame.
+  Result GenerateGenericBinaryOpStubCall(GenericBinaryOpStub* stub,
+                                         Result* left,
+                                         Result* right);
+
   // Emits code sequence that jumps to a JumpTarget if the inputs
   // are both smis.  Cannot be in MacroAssembler because it takes
   // advantage of TypeInfo to skip unneeded checks.
@@ -586,9 +591,7 @@ class CodeGenerator: public AstVisitor {
   };
   static InlineRuntimeLUT* FindInlineRuntimeLUT(Handle<String> name);
   bool CheckForInlineRuntimeCall(CallRuntime* node);
-  static bool PatchInlineRuntimeEntry(Handle<String> name,
-                                      const InlineRuntimeLUT& new_entry,
-                                      InlineRuntimeLUT* old_entry);
+
   void ProcessDeclarations(ZoneList<Declaration*>* declarations);
 
   static Handle<Code> ComputeCallInitialize(int argc, InLoopFlag in_loop);
@@ -659,6 +662,8 @@ class CodeGenerator: public AstVisitor {
 
   void GenerateRegExpConstructResult(ZoneList<Expression*>* args);
 
+  void GenerateRegExpCloneResult(ZoneList<Expression*>* args);
+
   // Support for fast native caches.
   void GenerateGetFromCache(ZoneList<Expression*>* args);
 
@@ -681,6 +686,9 @@ class CodeGenerator: public AstVisitor {
 
   void GenerateIsRegExpEquivalent(ZoneList<Expression*>* args);
 
+  void GenerateHasCachedArrayIndex(ZoneList<Expression*>* args);
+  void GenerateGetCachedArrayIndex(ZoneList<Expression*>* args);
+
 // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,
@@ -750,357 +758,6 @@ class CodeGenerator: public AstVisitor {
 };
 
 
-// Compute a transcendental math function natively, or call the
-// TranscendentalCache runtime function.
-class TranscendentalCacheStub: public CodeStub {
- public:
-  explicit TranscendentalCacheStub(TranscendentalCache::Type type)
-      : type_(type) {}
-  void Generate(MacroAssembler* masm);
- private:
-  TranscendentalCache::Type type_;
-  Major MajorKey() { return TranscendentalCache; }
-  int MinorKey() { return type_; }
-  Runtime::FunctionId RuntimeFunction();
-  void GenerateOperation(MacroAssembler* masm, Label* on_nan_result);
-};
-
-
-class ToBooleanStub: public CodeStub {
- public:
-  ToBooleanStub() { }
-
-  void Generate(MacroAssembler* masm);
-
- private:
-  Major MajorKey() { return ToBoolean; }
-  int MinorKey() { return 0; }
-};
-
-
-// Flag that indicates how to generate code for the stub GenericBinaryOpStub.
-enum GenericBinaryFlags {
-  NO_GENERIC_BINARY_FLAGS = 0,
-  NO_SMI_CODE_IN_STUB = 1 << 0  // Omit smi code in stub.
-};
-
-
-class GenericBinaryOpStub: public CodeStub {
- public:
-  GenericBinaryOpStub(Token::Value op,
-                      OverwriteMode mode,
-                      GenericBinaryFlags flags,
-                      TypeInfo operands_type = TypeInfo::Unknown())
-      : op_(op),
-        mode_(mode),
-        flags_(flags),
-        args_in_registers_(false),
-        args_reversed_(false),
-        static_operands_type_(operands_type),
-        runtime_operands_type_(BinaryOpIC::DEFAULT),
-        name_(NULL) {
-    ASSERT(OpBits::is_valid(Token::NUM_TOKENS));
-  }
-
-  GenericBinaryOpStub(int key, BinaryOpIC::TypeInfo type_info)
-      : op_(OpBits::decode(key)),
-        mode_(ModeBits::decode(key)),
-        flags_(FlagBits::decode(key)),
-        args_in_registers_(ArgsInRegistersBits::decode(key)),
-        args_reversed_(ArgsReversedBits::decode(key)),
-        static_operands_type_(TypeInfo::ExpandedRepresentation(
-            StaticTypeInfoBits::decode(key))),
-        runtime_operands_type_(type_info),
-        name_(NULL) {
-  }
-
-  // Generate code to call the stub with the supplied arguments. This will add
-  // code at the call site to prepare arguments either in registers or on the
-  // stack together with the actual call.
-  void GenerateCall(MacroAssembler* masm, Register left, Register right);
-  void GenerateCall(MacroAssembler* masm, Register left, Smi* right);
-  void GenerateCall(MacroAssembler* masm, Smi* left, Register right);
-
-  Result GenerateCall(MacroAssembler* masm,
-                      VirtualFrame* frame,
-                      Result* left,
-                      Result* right);
-
- private:
-  Token::Value op_;
-  OverwriteMode mode_;
-  GenericBinaryFlags flags_;
-  bool args_in_registers_;  // Arguments passed in registers not on the stack.
-  bool args_reversed_;  // Left and right argument are swapped.
-
-  // Number type information of operands, determined by code generator.
-  TypeInfo static_operands_type_;
-
-  // Operand type information determined at runtime.
-  BinaryOpIC::TypeInfo runtime_operands_type_;
-
-  char* name_;
-
-  const char* GetName();
-
-#ifdef DEBUG
-  void Print() {
-    PrintF("GenericBinaryOpStub %d (op %s), "
-           "(mode %d, flags %d, registers %d, reversed %d, only_numbers %s)\n",
-           MinorKey(),
-           Token::String(op_),
-           static_cast<int>(mode_),
-           static_cast<int>(flags_),
-           static_cast<int>(args_in_registers_),
-           static_cast<int>(args_reversed_),
-           static_operands_type_.ToString());
-  }
-#endif
-
-  // Minor key encoding in 17 bits TTNNNFRAOOOOOOOMM.
-  class ModeBits: public BitField<OverwriteMode, 0, 2> {};
-  class OpBits: public BitField<Token::Value, 2, 7> {};
-  class ArgsInRegistersBits: public BitField<bool, 9, 1> {};
-  class ArgsReversedBits: public BitField<bool, 10, 1> {};
-  class FlagBits: public BitField<GenericBinaryFlags, 11, 1> {};
-  class StaticTypeInfoBits: public BitField<int, 12, 3> {};
-  class RuntimeTypeInfoBits: public BitField<BinaryOpIC::TypeInfo, 15, 2> {};
-
-  Major MajorKey() { return GenericBinaryOp; }
-  int MinorKey() {
-    // Encode the parameters in a unique 18 bit value.
-    return OpBits::encode(op_)
-           | ModeBits::encode(mode_)
-           | FlagBits::encode(flags_)
-           | ArgsInRegistersBits::encode(args_in_registers_)
-           | ArgsReversedBits::encode(args_reversed_)
-           | StaticTypeInfoBits::encode(
-               static_operands_type_.ThreeBitRepresentation())
-           | RuntimeTypeInfoBits::encode(runtime_operands_type_);
-  }
-
-  void Generate(MacroAssembler* masm);
-  void GenerateSmiCode(MacroAssembler* masm, Label* slow);
-  void GenerateLoadArguments(MacroAssembler* masm);
-  void GenerateReturn(MacroAssembler* masm);
-  void GenerateRegisterArgsPush(MacroAssembler* masm);
-  void GenerateTypeTransition(MacroAssembler* masm);
-
-  bool ArgsInRegistersSupported() {
-    return (op_ == Token::ADD) || (op_ == Token::SUB)
-        || (op_ == Token::MUL) || (op_ == Token::DIV);
-  }
-  bool IsOperationCommutative() {
-    return (op_ == Token::ADD) || (op_ == Token::MUL);
-  }
-
-  void SetArgsInRegisters() { args_in_registers_ = true; }
-  void SetArgsReversed() { args_reversed_ = true; }
-  bool HasSmiCodeInStub() { return (flags_ & NO_SMI_CODE_IN_STUB) == 0; }
-  bool HasArgsInRegisters() { return args_in_registers_; }
-  bool HasArgsReversed() { return args_reversed_; }
-
-  bool ShouldGenerateSmiCode() {
-    return HasSmiCodeInStub() &&
-        runtime_operands_type_ != BinaryOpIC::HEAP_NUMBERS &&
-        runtime_operands_type_ != BinaryOpIC::STRINGS;
-  }
-
-  bool ShouldGenerateFPCode() {
-    return runtime_operands_type_ != BinaryOpIC::STRINGS;
-  }
-
-  virtual int GetCodeKind() { return Code::BINARY_OP_IC; }
-
-  virtual InlineCacheState GetICState() {
-    return BinaryOpIC::ToState(runtime_operands_type_);
-  }
-};
-
-class StringHelper : public AllStatic {
- public:
-  // Generate code for copying characters using a simple loop. This should only
-  // be used in places where the number of characters is small and the
-  // additional setup and checking in GenerateCopyCharactersREP adds too much
-  // overhead. Copying of overlapping regions is not supported.
-  static void GenerateCopyCharacters(MacroAssembler* masm,
-                                     Register dest,
-                                     Register src,
-                                     Register count,
-                                     bool ascii);
-
-  // Generate code for copying characters using the rep movs instruction.
-  // Copies rcx characters from rsi to rdi. Copying of overlapping regions is
-  // not supported.
-  static void GenerateCopyCharactersREP(MacroAssembler* masm,
-                                        Register dest,     // Must be rdi.
-                                        Register src,      // Must be rsi.
-                                        Register count,    // Must be rcx.
-                                        bool ascii);
-
-
-  // Probe the symbol table for a two character string. If the string is
-  // not found by probing a jump to the label not_found is performed. This jump
-  // does not guarantee that the string is not in the symbol table. If the
-  // string is found the code falls through with the string in register rax.
-  static void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
-                                                   Register c1,
-                                                   Register c2,
-                                                   Register scratch1,
-                                                   Register scratch2,
-                                                   Register scratch3,
-                                                   Register scratch4,
-                                                   Label* not_found);
-
-  // Generate string hash.
-  static void GenerateHashInit(MacroAssembler* masm,
-                               Register hash,
-                               Register character,
-                               Register scratch);
-  static void GenerateHashAddCharacter(MacroAssembler* masm,
-                                       Register hash,
-                                       Register character,
-                                       Register scratch);
-  static void GenerateHashGetHash(MacroAssembler* masm,
-                                  Register hash,
-                                  Register scratch);
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
-};
-
-
-// Flag that indicates how to generate code for the stub StringAddStub.
-enum StringAddFlags {
-  NO_STRING_ADD_FLAGS = 0,
-  NO_STRING_CHECK_IN_STUB = 1 << 0  // Omit string check in stub.
-};
-
-
-class StringAddStub: public CodeStub {
- public:
-  explicit StringAddStub(StringAddFlags flags) {
-    string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
-  }
-
- private:
-  Major MajorKey() { return StringAdd; }
-  int MinorKey() { return string_check_ ? 0 : 1; }
-
-  void Generate(MacroAssembler* masm);
-
-  // Should the stub check whether arguments are strings?
-  bool string_check_;
-};
-
-
-class SubStringStub: public CodeStub {
- public:
-  SubStringStub() {}
-
- private:
-  Major MajorKey() { return SubString; }
-  int MinorKey() { return 0; }
-
-  void Generate(MacroAssembler* masm);
-};
-
-
-class StringCompareStub: public CodeStub {
- public:
-  explicit StringCompareStub() {}
-
-  // Compare two flat ascii strings and returns result in rax after popping two
-  // arguments from the stack.
-  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
-                                              Register left,
-                                              Register right,
-                                              Register scratch1,
-                                              Register scratch2,
-                                              Register scratch3,
-                                              Register scratch4);
-
- private:
-  Major MajorKey() { return StringCompare; }
-  int MinorKey() { return 0; }
-
-  void Generate(MacroAssembler* masm);
-};
-
-
-class NumberToStringStub: public CodeStub {
- public:
-  NumberToStringStub() { }
-
-  // Generate code to do a lookup in the number string cache. If the number in
-  // the register object is found in the cache the generated code falls through
-  // with the result in the result register. The object and the result register
-  // can be the same. If the number is not found in the cache the code jumps to
-  // the label not_found with only the content of register object unchanged.
-  static void GenerateLookupNumberStringCache(MacroAssembler* masm,
-                                              Register object,
-                                              Register result,
-                                              Register scratch1,
-                                              Register scratch2,
-                                              bool object_is_smi,
-                                              Label* not_found);
-
- private:
-  static void GenerateConvertHashCodeToIndex(MacroAssembler* masm,
-                                             Register hash,
-                                             Register mask);
-
-  Major MajorKey() { return NumberToString; }
-  int MinorKey() { return 0; }
-
-  void Generate(MacroAssembler* masm);
-
-  const char* GetName() { return "NumberToStringStub"; }
-
-#ifdef DEBUG
-  void Print() {
-    PrintF("NumberToStringStub\n");
-  }
-#endif
-};
-
-
-class RecordWriteStub : public CodeStub {
- public:
-  RecordWriteStub(Register object, Register addr, Register scratch)
-      : object_(object), addr_(addr), scratch_(scratch) { }
-
-  void Generate(MacroAssembler* masm);
-
- private:
-  Register object_;
-  Register addr_;
-  Register scratch_;
-
-#ifdef DEBUG
-  void Print() {
-    PrintF("RecordWriteStub (object reg %d), (addr reg %d), (scratch reg %d)\n",
-           object_.code(), addr_.code(), scratch_.code());
-  }
-#endif
-
-  // Minor key encoding in 12 bits. 4 bits for each of the three
-  // registers (object, address and scratch) OOOOAAAASSSS.
-  class ScratchBits : public BitField<uint32_t, 0, 4> {};
-  class AddressBits : public BitField<uint32_t, 4, 4> {};
-  class ObjectBits : public BitField<uint32_t, 8, 4> {};
-
-  Major MajorKey() { return RecordWrite; }
-
-  int MinorKey() {
-    // Encode the registers.
-    return ObjectBits::encode(object_.code()) |
-           AddressBits::encode(addr_.code()) |
-           ScratchBits::encode(scratch_.code());
-  }
-};
-
-
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODEGEN_X64_H_
diff --git a/deps/v8/src/x64/debug-x64.cc b/deps/v8/src/x64/debug-x64.cc
index d5b7e7768c..2c1056f579 100644
--- a/deps/v8/src/x64/debug-x64.cc
+++ b/deps/v8/src/x64/debug-x64.cc
@@ -47,22 +47,35 @@ bool Debug::IsDebugBreakAtReturn(v8::internal::RelocInfo* rinfo) {
 #define __ ACCESS_MASM(masm)
 
 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
-                                          RegList pointer_regs,
+                                          RegList object_regs,
+                                          RegList non_object_regs,
                                           bool convert_call_to_jmp) {
-  // Save the content of all general purpose registers in memory. This copy in
-  // memory is later pushed onto the JS expression stack for the fake JS frame
-  // generated and also to the C frame generated on top of that. In the JS
-  // frame ONLY the registers containing pointers will be pushed on the
-  // expression stack. This causes the GC to update these pointers so that
-  // they will have the correct value when returning from the debugger.
-  __ SaveRegistersToMemory(kJSCallerSaved);
-
   // Enter an internal frame.
   __ EnterInternalFrame();
 
-  // Store the registers containing object pointers on the expression stack to
-  // make sure that these are correctly updated during GC.
-  __ PushRegistersFromMemory(pointer_regs);
+  // Store the registers containing live values on the expression stack to
+  // make sure that these are correctly updated during GC. Non object values
+  // are stored as as two smi causing it to be untouched by GC.
+  ASSERT((object_regs & ~kJSCallerSaved) == 0);
+  ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
+  ASSERT((object_regs & non_object_regs) == 0);
+  for (int i = 0; i < kNumJSCallerSaved; i++) {
+    int r = JSCallerSavedCode(i);
+    Register reg = { r };
+    ASSERT(!reg.is(kScratchRegister));
+    if ((object_regs & (1 << r)) != 0) {
+      __ push(reg);
+    }
+    // Store the 64-bit value as two smis.
+    if ((non_object_regs & (1 << r)) != 0) {
+      __ movq(kScratchRegister, reg);
+      __ Integer32ToSmi(reg, reg);
+      __ push(reg);
+      __ sar(kScratchRegister, Immediate(32));
+      __ Integer32ToSmi(kScratchRegister, kScratchRegister);
+      __ push(kScratchRegister);
+    }
+  }
 
 #ifdef DEBUG
   __ RecordComment("// Calling from debug break to runtime - come in - over");
@@ -70,12 +83,29 @@ static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
   __ xor_(rax, rax);  // No arguments (argc == 0).
   __ movq(rbx, ExternalReference::debug_break());
 
-  CEntryStub ceb(1, ExitFrame::MODE_DEBUG);
+  CEntryStub ceb(1);
   __ CallStub(&ceb);
 
-  // Restore the register values containing object pointers from the expression
-  // stack in the reverse order as they where pushed.
-  __ PopRegistersToMemory(pointer_regs);
+  // Restore the register values from the expression stack.
+  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+    int r = JSCallerSavedCode(i);
+    Register reg = { r };
+    if (FLAG_debug_code) {
+      __ Set(reg, kDebugZapValue);
+    }
+    if ((object_regs & (1 << r)) != 0) {
+      __ pop(reg);
+    }
+    // Reconstruct the 64-bit value from two smis.
+    if ((non_object_regs & (1 << r)) != 0) {
+      __ pop(kScratchRegister);
+      __ SmiToInteger32(kScratchRegister, kScratchRegister);
+      __ shl(kScratchRegister, Immediate(32));
+      __ pop(reg);
+      __ SmiToInteger32(reg, reg);
+      __ or_(reg, kScratchRegister);
+    }
+  }
 
   // Get rid of the internal frame.
   __ LeaveInternalFrame();
@@ -83,12 +113,9 @@ static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
   // If this call did not replace a call but patched other code then there will
   // be an unwanted return address left on the stack. Here we get rid of that.
   if (convert_call_to_jmp) {
-    __ pop(rax);
+    __ addq(rsp, Immediate(kPointerSize));
   }
 
-  // Finally restore all registers.
-  __ RestoreRegistersFromMemory(kJSCallerSaved);
-
   // Now that the break point has been handled, resume normal execution by
   // jumping to the target address intended by the caller and that was
   // overwritten by the address of DebugBreakXXX.
@@ -100,12 +127,11 @@ static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
 
 
 void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
-  // Register state for keyed IC call call (from ic-x64.cc)
+  // Register state for IC call call (from ic-x64.cc)
   // ----------- S t a t e -------------
-  //  -- rax: number of arguments
+  //  -- rcx: function name
   // -----------------------------------
-  // The number of arguments in rax is not smi encoded.
-  Generate_DebugBreakCallHelper(masm, 0, false);
+  Generate_DebugBreakCallHelper(masm, rcx.bit(), 0, false);
 }
 
 
@@ -117,7 +143,7 @@ void Debug::GenerateConstructCallDebugBreak(MacroAssembler* masm) {
   //  -- rax: number of arguments
   // -----------------------------------
   // The number of arguments in rax is not smi encoded.
-  Generate_DebugBreakCallHelper(masm, 0, false);
+  Generate_DebugBreakCallHelper(masm, rdi.bit(), rax.bit(), false);
 }
 
 
@@ -127,7 +153,7 @@ void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
   //  -- rax     : key
   //  -- rdx     : receiver
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, rax.bit() | rdx.bit(), false);
+  Generate_DebugBreakCallHelper(masm, rax.bit() | rdx.bit(), 0, false);
 }
 
 
@@ -138,7 +164,8 @@ void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
   //  -- rcx    : key
   //  -- rdx    : receiver
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit() | rdx.bit(), false);
+  Generate_DebugBreakCallHelper(
+      masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false);
 }
 
 
@@ -148,7 +175,7 @@ void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
   //  -- rax    : receiver
   //  -- rcx    : name
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit(), false);
+  Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit(), 0, false);
 }
 
 
@@ -157,7 +184,7 @@ void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax: return value
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, rax.bit(), true);
+  Generate_DebugBreakCallHelper(masm, rax.bit(), 0, true);
 }
 
 
@@ -168,7 +195,8 @@ void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
   //  -- rcx    : name
   //  -- rdx    : receiver
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit() | rdx.bit(), false);
+  Generate_DebugBreakCallHelper(
+      masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false);
 }
 
 
@@ -177,7 +205,7 @@ void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  No registers used on entry.
   // -----------------------------------
-  Generate_DebugBreakCallHelper(masm, 0, false);
+  Generate_DebugBreakCallHelper(masm, 0, 0, false);
 }
 
 
@@ -197,7 +225,7 @@ void Debug::GenerateSlot(MacroAssembler* masm) {
 void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
   // In the places where a debug break slot is inserted no registers can contain
   // object pointers.
-  Generate_DebugBreakCallHelper(masm, 0, true);
+  Generate_DebugBreakCallHelper(masm, 0, 0, true);
 }
 
 
diff --git a/deps/v8/src/x64/frames-x64.cc b/deps/v8/src/x64/frames-x64.cc
index 85ebc9586b..fd26535155 100644
--- a/deps/v8/src/x64/frames-x64.cc
+++ b/deps/v8/src/x64/frames-x64.cc
@@ -35,19 +35,6 @@ namespace v8 {
 namespace internal {
 
 
-StackFrame::Type StackFrame::ComputeType(State* state) {
-  ASSERT(state->fp != NULL);
-  if (StandardFrame::IsArgumentsAdaptorFrame(state->fp)) {
-    return ARGUMENTS_ADAPTOR;
-  }
-  // The marker and function offsets overlap. If the marker isn't a
-  // smi then the frame is a JavaScript frame -- and the marker is
-  // really the function.
-  const int offset = StandardFrameConstants::kMarkerOffset;
-  Object* marker = Memory::Object_at(state->fp + offset);
-  if (!marker->IsSmi()) return JAVA_SCRIPT;
-  return static_cast<StackFrame::Type>(Smi::cast(marker)->value());
-}
 
 
 StackFrame::Type ExitFrame::GetStateForFramePointer(Address fp, State* state) {
@@ -58,55 +45,10 @@ StackFrame::Type ExitFrame::GetStateForFramePointer(Address fp, State* state) {
   state->fp = fp;
   state->sp = sp;
   state->pc_address = reinterpret_cast<Address*>(sp - 1 * kPointerSize);
-  // Determine frame type.
+  ASSERT(*state->pc_address != NULL);
   return EXIT;
 }
 
-int JavaScriptFrame::GetProvidedParametersCount() const {
-  return ComputeParametersCount();
-}
-
-
-void ExitFrame::Iterate(ObjectVisitor* v) const {
-  v->VisitPointer(&code_slot());
-  // The arguments are traversed as part of the expression stack of
-  // the calling frame.
-}
-
-byte* InternalFrame::GetCallerStackPointer() const {
-  // Internal frames have no arguments. The stack pointer of the
-  // caller is at a fixed offset from the frame pointer.
-  return fp() + StandardFrameConstants::kCallerSPOffset;
-}
-
-byte* JavaScriptFrame::GetCallerStackPointer() const {
-  int arguments;
-  if (Heap::gc_state() != Heap::NOT_IN_GC || disable_heap_access_) {
-    // The arguments for cooked frames are traversed as if they were
-    // expression stack elements of the calling frame. The reason for
-    // this rather strange decision is that we cannot access the
-    // function during mark-compact GCs when the stack is cooked.
-    // In fact accessing heap objects (like function->shared() below)
-    // at all during GC is problematic.
-    arguments = 0;
-  } else {
-    // Compute the number of arguments by getting the number of formal
-    // parameters of the function. We must remember to take the
-    // receiver into account (+1).
-    JSFunction* function = JSFunction::cast(this->function());
-    arguments = function->shared()->formal_parameter_count() + 1;
-  }
-  const int offset = StandardFrameConstants::kCallerSPOffset;
-  return fp() + offset + (arguments * kPointerSize);
-}
-
-
-byte* ArgumentsAdaptorFrame::GetCallerStackPointer() const {
-  const int arguments = Smi::cast(GetExpression(0))->value();
-  const int offset = StandardFrameConstants::kCallerSPOffset;
-  return fp() + offset + (arguments + 1) * kPointerSize;
-}
-
 
 } }  // namespace v8::internal
 
diff --git a/deps/v8/src/x64/full-codegen-x64.cc b/deps/v8/src/x64/full-codegen-x64.cc
index 725cbb0c58..ccd0392a30 100644
--- a/deps/v8/src/x64/full-codegen-x64.cc
+++ b/deps/v8/src/x64/full-codegen-x64.cc
@@ -29,6 +29,7 @@
 
 #if defined(V8_TARGET_ARCH_X64)
 
+#include "code-stubs.h"
 #include "codegen-inl.h"
 #include "compiler.h"
 #include "debug.h"
@@ -229,6 +230,13 @@ void FullCodeGenerator::EmitReturnSequence() {
 }
 
 
+FullCodeGenerator::ConstantOperand FullCodeGenerator::GetConstantOperand(
+    Token::Value op, Expression* left, Expression* right) {
+  ASSERT(ShouldInlineSmiCase(op));
+  return kNoConstants;
+}
+
+
 void FullCodeGenerator::Apply(Expression::Context context, Register reg) {
   switch (context) {
     case Expression::kUninitialized:
@@ -253,20 +261,7 @@ void FullCodeGenerator::Apply(Expression::Context context, Register reg) {
     case Expression::kTest:
       // For simplicity we always test the accumulator register.
       if (!reg.is(result_register())) __ movq(result_register(), reg);
-      DoTest(context);
-      break;
-
-    case Expression::kValueTest:
-    case Expression::kTestValue:
-      if (!reg.is(result_register())) __ movq(result_register(), reg);
-      switch (location_) {
-        case kAccumulator:
-          break;
-        case kStack:
-          __ push(result_register());
-          break;
-      }
-      DoTest(context);
+      DoTest(true_label_, false_label_, fall_through_);
       break;
   }
 }
@@ -295,20 +290,7 @@ void FullCodeGenerator::Apply(Expression::Context context, Slot* slot) {
 
     case Expression::kTest:
       Move(result_register(), slot);
-      DoTest(context);
-      break;
-
-    case Expression::kValueTest:
-    case Expression::kTestValue:
-      Move(result_register(), slot);
-      switch (location_) {
-        case kAccumulator:
-          break;
-        case kStack:
-          __ push(result_register());
-          break;
-      }
-      DoTest(context);
+      DoTest(true_label_, false_label_, fall_through_);
       break;
   }
 }
@@ -334,20 +316,7 @@ void FullCodeGenerator::Apply(Expression::Context context, Literal* lit) {
 
     case Expression::kTest:
       __ Move(result_register(), lit->handle());
-      DoTest(context);
-      break;
-
-    case Expression::kValueTest:
-    case Expression::kTestValue:
-      __ Move(result_register(), lit->handle());
-      switch (location_) {
-        case kAccumulator:
-          break;
-        case kStack:
-          __ push(result_register());
-          break;
-      }
-      DoTest(context);
+      DoTest(true_label_, false_label_, fall_through_);
       break;
   }
 }
@@ -374,20 +343,7 @@ void FullCodeGenerator::ApplyTOS(Expression::Context context) {
 
     case Expression::kTest:
       __ pop(result_register());
-      DoTest(context);
-      break;
-
-    case Expression::kValueTest:
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          __ pop(result_register());
-          break;
-        case kStack:
-          __ movq(result_register(), Operand(rsp, 0));
-          break;
-      }
-      DoTest(context);
+      DoTest(true_label_, false_label_, fall_through_);
       break;
   }
 }
@@ -422,56 +378,7 @@ void FullCodeGenerator::DropAndApply(int count,
     case Expression::kTest:
       __ Drop(count);
       if (!reg.is(result_register())) __ movq(result_register(), reg);
-      DoTest(context);
-      break;
-
-    case Expression::kValueTest:
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          __ Drop(count);
-          if (!reg.is(result_register())) __ movq(result_register(), reg);
-          break;
-        case kStack:
-          if (count > 1) __ Drop(count - 1);
-          __ movq(result_register(), reg);
-          __ movq(Operand(rsp, 0), result_register());
-          break;
-      }
-      DoTest(context);
-      break;
-  }
-}
-
-
-void FullCodeGenerator::PrepareTest(Label* materialize_true,
-                                    Label* materialize_false,
-                                    Label** if_true,
-                                    Label** if_false) {
-  switch (context_) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-      break;
-    case Expression::kEffect:
-      // In an effect context, the true and the false case branch to the
-      // same label.
-      *if_true = *if_false = materialize_true;
-      break;
-    case Expression::kValue:
-      *if_true = materialize_true;
-      *if_false = materialize_false;
-      break;
-    case Expression::kTest:
-      *if_true = true_label_;
-      *if_false = false_label_;
-      break;
-    case Expression::kValueTest:
-      *if_true = materialize_true;
-      *if_false = false_label_;
-      break;
-    case Expression::kTestValue:
-      *if_true = true_label_;
-      *if_false = materialize_false;
+      DoTest(true_label_, false_label_, fall_through_);
       break;
   }
 }
@@ -512,32 +419,6 @@ void FullCodeGenerator::Apply(Expression::Context context,
 
     case Expression::kTest:
       break;
-
-    case Expression::kValueTest:
-      __ bind(materialize_true);
-      switch (location_) {
-        case kAccumulator:
-          __ Move(result_register(), Factory::true_value());
-          break;
-        case kStack:
-          __ Push(Factory::true_value());
-          break;
-      }
-      __ jmp(true_label_);
-      break;
-
-    case Expression::kTestValue:
-      __ bind(materialize_false);
-      switch (location_) {
-        case kAccumulator:
-          __ Move(result_register(), Factory::false_value());
-          break;
-        case kStack:
-          __ Push(Factory::false_value());
-          break;
-      }
-      __ jmp(false_label_);
-      break;
   }
 }
 
@@ -565,78 +446,19 @@ void FullCodeGenerator::Apply(Expression::Context context, bool flag) {
       break;
     }
     case Expression::kTest:
-      __ jmp(flag ? true_label_ : false_label_);
-      break;
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          // If value is false it's needed.
-          if (!flag) __ LoadRoot(result_register(), Heap::kFalseValueRootIndex);
-          break;
-        case kStack:
-          // If value is false it's needed.
-          if (!flag) __ PushRoot(Heap::kFalseValueRootIndex);
-          break;
-      }
-      __ jmp(flag ? true_label_ : false_label_);
-      break;
-    case Expression::kValueTest:
-      switch (location_) {
-        case kAccumulator:
-          // If value is true it's needed.
-          if (flag) __ LoadRoot(result_register(), Heap::kTrueValueRootIndex);
-          break;
-        case kStack:
-          // If value is true it's needed.
-          if (flag) __ PushRoot(Heap::kTrueValueRootIndex);
-          break;
+      if (flag) {
+        if (true_label_ != fall_through_) __ jmp(true_label_);
+      } else {
+        if (false_label_ != fall_through_) __ jmp(false_label_);
       }
-      __ jmp(flag ? true_label_ : false_label_);
       break;
   }
 }
 
 
-void FullCodeGenerator::DoTest(Expression::Context context) {
-  // The value to test is in the accumulator.  If the value might be needed
-  // on the stack (value/test and test/value contexts with a stack location
-  // desired), then the value is already duplicated on the stack.
-  ASSERT_NE(NULL, true_label_);
-  ASSERT_NE(NULL, false_label_);
-
-  // In value/test and test/value expression contexts with stack as the
-  // desired location, there is already an extra value on the stack.  Use a
-  // label to discard it if unneeded.
-  Label discard;
-  Label* if_true = true_label_;
-  Label* if_false = false_label_;
-  switch (context) {
-    case Expression::kUninitialized:
-    case Expression::kEffect:
-    case Expression::kValue:
-      UNREACHABLE();
-    case Expression::kTest:
-      break;
-    case Expression::kValueTest:
-      switch (location_) {
-        case kAccumulator:
-          break;
-        case kStack:
-          if_false = &discard;
-          break;
-      }
-      break;
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          break;
-        case kStack:
-          if_true = &discard;
-          break;
-      }
-      break;
-  }
-
+void FullCodeGenerator::DoTest(Label* if_true,
+                               Label* if_false,
+                               Label* fall_through) {
   // Emit the inlined tests assumed by the stub.
   __ CompareRoot(result_register(), Heap::kUndefinedValueRootIndex);
   __ j(equal, if_false);
@@ -650,83 +472,28 @@ void FullCodeGenerator::DoTest(Expression::Context context) {
   Condition is_smi = masm_->CheckSmi(result_register());
   __ j(is_smi, if_true);
 
-  // Save a copy of the value if it may be needed and isn't already saved.
-  switch (context) {
-    case Expression::kUninitialized:
-    case Expression::kEffect:
-    case Expression::kValue:
-      UNREACHABLE();
-    case Expression::kTest:
-      break;
-    case Expression::kValueTest:
-      switch (location_) {
-        case kAccumulator:
-          __ push(result_register());
-          break;
-        case kStack:
-          break;
-      }
-      break;
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          __ push(result_register());
-          break;
-        case kStack:
-          break;
-      }
-      break;
-  }
-
   // Call the ToBoolean stub for all other cases.
   ToBooleanStub stub;
   __ push(result_register());
   __ CallStub(&stub);
   __ testq(rax, rax);
 
-  // The stub returns nonzero for true.  Complete based on the context.
-  switch (context) {
-    case Expression::kUninitialized:
-    case Expression::kEffect:
-    case Expression::kValue:
-      UNREACHABLE();
-
-    case Expression::kTest:
-      __ j(not_zero, true_label_);
-      __ jmp(false_label_);
-      break;
+  // The stub returns nonzero for true.
+  Split(not_zero, if_true, if_false, fall_through);
+}
 
-    case Expression::kValueTest:
-      switch (location_) {
-        case kAccumulator:
-          __ j(zero, &discard);
-          __ pop(result_register());
-          __ jmp(true_label_);
-          break;
-        case kStack:
-          __ j(not_zero, true_label_);
-          break;
-      }
-      __ bind(&discard);
-      __ Drop(1);
-      __ jmp(false_label_);
-      break;
 
-    case Expression::kTestValue:
-      switch (location_) {
-        case kAccumulator:
-          __ j(not_zero, &discard);
-          __ pop(result_register());
-          __ jmp(false_label_);
-          break;
-        case kStack:
-          __ j(zero, false_label_);
-          break;
-      }
-      __ bind(&discard);
-      __ Drop(1);
-      __ jmp(true_label_);
-      break;
+void FullCodeGenerator::Split(Condition cc,
+                              Label* if_true,
+                              Label* if_false,
+                              Label* fall_through) {
+  if (if_false == fall_through) {
+    __ j(cc, if_true);
+  } else if (if_true == fall_through) {
+    __ j(NegateCondition(cc), if_false);
+  } else {
+    __ j(cc, if_true);
+    __ jmp(if_false);
   }
 }
 
@@ -912,17 +679,18 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     // Compile the label expression.
     VisitForValue(clause->label(), kAccumulator);
 
-    // Perform the comparison as if via '==='.  The comparison stub expects
-    // the smi vs. smi case to be handled before it is called.
-    Label slow_case;
-    __ movq(rdx, Operand(rsp, 0));  // Switch value.
-    __ JumpIfNotBothSmi(rdx, rax, &slow_case);
-    __ SmiCompare(rdx, rax);
-    __ j(not_equal, &next_test);
-    __ Drop(1);  // Switch value is no longer needed.
-    __ jmp(clause->body_target()->entry_label());
+    // Perform the comparison as if via '==='.
+    if (ShouldInlineSmiCase(Token::EQ_STRICT)) {
+      Label slow_case;
+      __ movq(rdx, Operand(rsp, 0));  // Switch value.
+      __ JumpIfNotBothSmi(rdx, rax, &slow_case);
+      __ SmiCompare(rdx, rax);
+      __ j(not_equal, &next_test);
+      __ Drop(1);  // Switch value is no longer needed.
+      __ jmp(clause->body_target()->entry_label());
+      __ bind(&slow_case);
+    }
 
-    __ bind(&slow_case);
     CompareStub stub(equal, true);
     __ CallStub(&stub);
     __ testq(rax, rax);
@@ -1206,7 +974,7 @@ void FullCodeGenerator::VisitRegExpLiteral(RegExpLiteral* expr) {
   __ movq(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
   __ movq(rcx, FieldOperand(rdi, JSFunction::kLiteralsOffset));
   int literal_offset =
-    FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
+      FixedArray::kHeaderSize + expr->literal_index() * kPointerSize;
   __ movq(rbx, FieldOperand(rcx, literal_offset));
   __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
   __ j(not_equal, &materialized);
@@ -1330,12 +1098,18 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   __ push(FieldOperand(rbx, JSFunction::kLiteralsOffset));
   __ Push(Smi::FromInt(expr->literal_index()));
   __ Push(expr->constant_elements());
-  if (expr->depth() > 1) {
+  if (expr->constant_elements()->map() == Heap::fixed_cow_array_map()) {
+    FastCloneShallowArrayStub stub(
+        FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS, length);
+    __ CallStub(&stub);
+    __ IncrementCounter(&Counters::cow_arrays_created_stub, 1);
+  } else if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateArrayLiteral, 3);
-  } else if (length > FastCloneShallowArrayStub::kMaximumLength) {
+  } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
     __ CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   } else {
-    FastCloneShallowArrayStub stub(length);
+    FastCloneShallowArrayStub stub(
+        FastCloneShallowArrayStub::CLONE_ELEMENTS, length);
     __ CallStub(&stub);
   }
 
@@ -1389,10 +1163,11 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
   // slot. Variables with rewrite to .arguments are treated as KEYED_PROPERTY.
   enum LhsKind { VARIABLE, NAMED_PROPERTY, KEYED_PROPERTY };
   LhsKind assign_type = VARIABLE;
-  Property* prop = expr->target()->AsProperty();
-  if (prop != NULL) {
-    assign_type =
-        (prop->key()->IsPropertyName()) ? NAMED_PROPERTY : KEYED_PROPERTY;
+  Property* property = expr->target()->AsProperty();
+  if (property != NULL) {
+    assign_type = (property->key()->IsPropertyName())
+        ? NAMED_PROPERTY
+        : KEYED_PROPERTY;
   }
 
   // Evaluate LHS expression.
@@ -1403,57 +1178,70 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
     case NAMED_PROPERTY:
       if (expr->is_compound()) {
         // We need the receiver both on the stack and in the accumulator.
-        VisitForValue(prop->obj(), kAccumulator);
+        VisitForValue(property->obj(), kAccumulator);
         __ push(result_register());
       } else {
-        VisitForValue(prop->obj(), kStack);
+        VisitForValue(property->obj(), kStack);
       }
       break;
     case KEYED_PROPERTY:
       if (expr->is_compound()) {
-        VisitForValue(prop->obj(), kStack);
-        VisitForValue(prop->key(), kAccumulator);
+        VisitForValue(property->obj(), kStack);
+        VisitForValue(property->key(), kAccumulator);
         __ movq(rdx, Operand(rsp, 0));
         __ push(rax);
       } else {
-        VisitForValue(prop->obj(), kStack);
-        VisitForValue(prop->key(), kStack);
+        VisitForValue(property->obj(), kStack);
+        VisitForValue(property->key(), kStack);
       }
       break;
   }
 
-  // If we have a compound assignment: Get value of LHS expression and
-  // store in on top of the stack.
   if (expr->is_compound()) {
     Location saved_location = location_;
-    location_ = kStack;
+    location_ = kAccumulator;
     switch (assign_type) {
       case VARIABLE:
         EmitVariableLoad(expr->target()->AsVariableProxy()->var(),
                          Expression::kValue);
         break;
       case NAMED_PROPERTY:
-        EmitNamedPropertyLoad(prop);
-        __ push(result_register());
+        EmitNamedPropertyLoad(property);
         break;
       case KEYED_PROPERTY:
-        EmitKeyedPropertyLoad(prop);
-        __ push(result_register());
+        EmitKeyedPropertyLoad(property);
         break;
     }
-    location_ = saved_location;
-  }
 
-  // Evaluate RHS expression.
-  Expression* rhs = expr->value();
-  VisitForValue(rhs, kAccumulator);
+    Token::Value op = expr->binary_op();
+    ConstantOperand constant = ShouldInlineSmiCase(op)
+        ? GetConstantOperand(op, expr->target(), expr->value())
+        : kNoConstants;
+    ASSERT(constant == kRightConstant || constant == kNoConstants);
+    if (constant == kNoConstants) {
+      __ push(rax);  // Left operand goes on the stack.
+      VisitForValue(expr->value(), kAccumulator);
+    }
 
-  // If we have a compound assignment: Apply operator.
-  if (expr->is_compound()) {
-    Location saved_location = location_;
-    location_ = kAccumulator;
-    EmitBinaryOp(expr->binary_op(), Expression::kValue);
+    OverwriteMode mode = expr->value()->ResultOverwriteAllowed()
+        ? OVERWRITE_RIGHT
+        : NO_OVERWRITE;
+    SetSourcePosition(expr->position() + 1);
+    if (ShouldInlineSmiCase(op)) {
+      EmitInlineSmiBinaryOp(expr,
+                            op,
+                            Expression::kValue,
+                            mode,
+                            expr->target(),
+                            expr->value(),
+                            constant);
+    } else {
+      EmitBinaryOp(op, Expression::kValue, mode);
+    }
     location_ = saved_location;
+
+  } else {
+    VisitForValue(expr->value(), kAccumulator);
   }
 
   // Record source position before possible IC call.
@@ -1494,13 +1282,85 @@ void FullCodeGenerator::EmitKeyedPropertyLoad(Property* prop) {
 }
 
 
+void FullCodeGenerator::EmitInlineSmiBinaryOp(Expression* expr,
+                                              Token::Value op,
+                                              Expression::Context context,
+                                              OverwriteMode mode,
+                                              Expression* left,
+                                              Expression* right,
+                                              ConstantOperand constant) {
+  ASSERT(constant == kNoConstants);  // Only handled case.
+
+  // Do combined smi check of the operands. Left operand is on the
+  // stack (popped into rdx). Right operand is in rax but moved into
+  // rcx to make the shifts easier.
+  Label done, stub_call, smi_case;
+  __ pop(rdx);
+  __ movq(rcx, rax);
+  Condition smi = __ CheckBothSmi(rdx, rax);
+  __ j(smi, &smi_case);
+
+  __ bind(&stub_call);
+  GenericBinaryOpStub stub(op, mode, NO_SMI_CODE_IN_STUB, TypeInfo::Unknown());
+  if (stub.ArgsInRegistersSupported()) {
+    stub.GenerateCall(masm_, rdx, rcx);
+  } else {
+    __ push(rdx);
+    __ push(rcx);
+    __ CallStub(&stub);
+  }
+  __ jmp(&done);
+
+  __ bind(&smi_case);
+  switch (op) {
+    case Token::SAR:
+      __ SmiShiftArithmeticRight(rax, rdx, rcx);
+      break;
+    case Token::SHL:
+      __ SmiShiftLeft(rax, rdx, rcx);
+      break;
+    case Token::SHR:
+      __ SmiShiftLogicalRight(rax, rdx, rcx, &stub_call);
+      break;
+    case Token::ADD:
+      __ SmiAdd(rax, rdx, rcx, &stub_call);
+      break;
+    case Token::SUB:
+      __ SmiSub(rax, rdx, rcx, &stub_call);
+      break;
+    case Token::MUL:
+      __ SmiMul(rax, rdx, rcx, &stub_call);
+      break;
+    case Token::BIT_OR:
+      __ SmiOr(rax, rdx, rcx);
+      break;
+    case Token::BIT_AND:
+      __ SmiAnd(rax, rdx, rcx);
+      break;
+    case Token::BIT_XOR:
+      __ SmiXor(rax, rdx, rcx);
+      break;
+    default:
+      UNREACHABLE();
+      break;
+  }
+
+  __ bind(&done);
+  Apply(context, rax);
+}
+
+
 void FullCodeGenerator::EmitBinaryOp(Token::Value op,
-                                     Expression::Context context) {
-  __ push(result_register());
-  GenericBinaryOpStub stub(op,
-                           NO_OVERWRITE,
-                           NO_GENERIC_BINARY_FLAGS);
-  __ CallStub(&stub);
+                                     Expression::Context context,
+                                     OverwriteMode mode) {
+  GenericBinaryOpStub stub(op, mode, NO_GENERIC_BINARY_FLAGS);
+  if (stub.ArgsInRegistersSupported()) {
+    __ pop(rdx);
+    stub.GenerateCall(masm_, rdx, rax);
+  } else {
+    __ push(result_register());
+    __ CallStub(&stub);
+  }
   Apply(context, rax);
 }
 
@@ -1923,11 +1783,11 @@ void FullCodeGenerator::VisitCallNew(CallNew* expr) {
   // According to ECMA-262, section 11.2.2, page 44, the function
   // expression in new calls must be evaluated before the
   // arguments.
-  // Push function on the stack.
-  VisitForValue(expr->expression(), kStack);
 
-  // Push global object (receiver).
-  __ push(CodeGenerator::GlobalObject());
+  // Push constructor on the stack.  If it's not a function it's used as
+  // receiver for CALL_NON_FUNCTION, otherwise the value on the stack is
+  // ignored.
+  VisitForValue(expr->expression(), kStack);
 
   // Push the arguments ("left-to-right") on the stack.
   ZoneList<Expression*>* args = expr->arguments();
@@ -1940,16 +1800,13 @@ void FullCodeGenerator::VisitCallNew(CallNew* expr) {
   // constructor invocation.
   SetSourcePosition(expr->position());
 
-  // Load function, arg_count into rdi and rax.
+  // Load function and argument count into rdi and rax.
   __ Set(rax, arg_count);
-  // Function is in rsp[arg_count + 1].
-  __ movq(rdi, Operand(rsp, rax, times_pointer_size, kPointerSize));
+  __ movq(rdi, Operand(rsp, arg_count * kPointerSize));
 
   Handle<Code> construct_builtin(Builtins::builtin(Builtins::JSConstructCall));
   __ Call(construct_builtin, RelocInfo::CONSTRUCT_CALL);
-
-  // Replace function on TOS with result in rax, or pop it.
-  DropAndApply(1, context_, rax);
+  Apply(context_, rax);
 }
 
 
@@ -1961,7 +1818,9 @@ void FullCodeGenerator::EmitIsSmi(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_true);
   __ jmp(if_false);
@@ -1978,11 +1837,12 @@ void FullCodeGenerator::EmitIsNonNegativeSmi(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   Condition positive_smi = __ CheckPositiveSmi(rax);
-  __ j(positive_smi, if_true);
-  __ jmp(if_false);
+  Split(positive_smi, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -1996,7 +1856,9 @@ void FullCodeGenerator::EmitIsObject(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ CompareRoot(rax, Heap::kNullValueRootIndex);
@@ -2010,8 +1872,7 @@ void FullCodeGenerator::EmitIsObject(ZoneList<Expression*>* args) {
   __ cmpq(rbx, Immediate(FIRST_JS_OBJECT_TYPE));
   __ j(below, if_false);
   __ cmpq(rbx, Immediate(LAST_JS_OBJECT_TYPE));
-  __ j(below_equal, if_true);
-  __ jmp(if_false);
+  Split(below_equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2025,12 +1886,13 @@ void FullCodeGenerator::EmitIsSpecObject(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ CmpObjectType(rax, FIRST_JS_OBJECT_TYPE, rbx);
-  __ j(above_equal, if_true);
-  __ jmp(if_false);
+  Split(above_equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2044,14 +1906,15 @@ void FullCodeGenerator::EmitIsUndetectableObject(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
   __ testb(FieldOperand(rbx, Map::kBitFieldOffset),
            Immediate(1 << Map::kIsUndetectable));
-  __ j(not_zero, if_true);
-  __ jmp(if_false);
+  Split(not_zero, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2066,7 +1929,9 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   // Just indicate false, as %_IsStringWrapperSafeForDefaultValueOf() is only
   // used in a few functions in runtime.js which should not normally be hit by
@@ -2084,12 +1949,13 @@ void FullCodeGenerator::EmitIsFunction(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ CmpObjectType(rax, JS_FUNCTION_TYPE, rbx);
-  __ j(equal, if_true);
-  __ jmp(if_false);
+  Split(equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2103,12 +1969,13 @@ void FullCodeGenerator::EmitIsArray(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ CmpObjectType(rax, JS_ARRAY_TYPE, rbx);
-  __ j(equal, if_true);
-  __ jmp(if_false);
+  Split(equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2122,12 +1989,13 @@ void FullCodeGenerator::EmitIsRegExp(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ JumpIfSmi(rax, if_false);
   __ CmpObjectType(rax, JS_REGEXP_TYPE, rbx);
-  __ j(equal, if_true);
-  __ jmp(if_false);
+  Split(equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2140,7 +2008,9 @@ void FullCodeGenerator::EmitIsConstructCall(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   // Get the frame pointer for the calling frame.
   __ movq(rax, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
@@ -2156,8 +2026,7 @@ void FullCodeGenerator::EmitIsConstructCall(ZoneList<Expression*>* args) {
   __ bind(&check_frame_marker);
   __ SmiCompare(Operand(rax, StandardFrameConstants::kMarkerOffset),
                 Smi::FromInt(StackFrame::CONSTRUCT));
-  __ j(equal, if_true);
-  __ jmp(if_false);
+  Split(equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2173,12 +2042,13 @@ void FullCodeGenerator::EmitObjectEquals(ZoneList<Expression*>* args) {
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
 
   __ pop(rbx);
   __ cmpq(rax, rbx);
-  __ j(equal, if_true);
-  __ jmp(if_false);
+  Split(equal, if_true, if_false, fall_through);
 
   Apply(context_, if_true, if_false);
 }
@@ -2187,8 +2057,8 @@ void FullCodeGenerator::EmitObjectEquals(ZoneList<Expression*>* args) {
 void FullCodeGenerator::EmitArguments(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
 
-  // ArgumentsAccessStub expects the key in edx and the formal
-  // parameter count in eax.
+  // ArgumentsAccessStub expects the key in rdx and the formal
+  // parameter count in rax.
   VisitForValue(args->at(0), kAccumulator);
   __ movq(rdx, rax);
   __ Move(rax, Smi::FromInt(scope()->num_parameters()));
@@ -2392,7 +2262,7 @@ void FullCodeGenerator::EmitSetValueOf(ZoneList<Expression*>* args) {
 
   VisitForValue(args->at(0), kStack);  // Load the object.
   VisitForValue(args->at(1), kAccumulator);  // Load the value.
-  __ pop(rbx);  // rax = value. ebx = object.
+  __ pop(rbx);  // rax = value. rbx = object.
 
   Label done;
   // If the object is a smi, return the value.
@@ -2727,6 +2597,40 @@ void FullCodeGenerator::EmitIsRegExpEquivalent(ZoneList<Expression*>* args) {
 }
 
 
+void FullCodeGenerator::EmitHasCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+
+  VisitForValue(args->at(0), kAccumulator);
+
+  Label materialize_true, materialize_false;
+  Label* if_true = NULL;
+  Label* if_false = NULL;
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
+
+  __ testl(FieldOperand(rax, String::kHashFieldOffset),
+           Immediate(String::kContainsCachedArrayIndexMask));
+  __ j(zero, if_true);
+  __ jmp(if_false);
+
+  Apply(context_, if_true, if_false);
+}
+
+
+void FullCodeGenerator::EmitGetCachedArrayIndex(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+
+  VisitForValue(args->at(0), kAccumulator);
+
+  __ movl(rax, FieldOperand(rax, String::kHashFieldOffset));
+  ASSERT(String::kHashShift >= kSmiTagSize);
+  __ IndexFromHash(rax, rax);
+
+  Apply(context_, rax);
+}
+
+
 void FullCodeGenerator::VisitCallRuntime(CallRuntime* expr) {
   Handle<String> name = expr->name();
   if (name->length() > 0 && name->Get(0) == '_') {
@@ -2826,19 +2730,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
               break;
           }
           break;
-        case Expression::kTestValue:
-          // Value is false so it's needed.
-          switch (location_) {
-            case kAccumulator:
-              __ LoadRoot(result_register(), Heap::kUndefinedValueRootIndex);
-              break;
-            case kStack:
-              __ PushRoot(Heap::kUndefinedValueRootIndex);
-              break;
-          }
-          // Fall through.
         case Expression::kTest:
-        case Expression::kValueTest:
           __ jmp(false_label_);
           break;
       }
@@ -2850,42 +2742,18 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
       Label materialize_true, materialize_false;
       Label* if_true = NULL;
       Label* if_false = NULL;
-
+      Label* fall_through = NULL;
       // Notice that the labels are swapped.
-      PrepareTest(&materialize_true, &materialize_false, &if_false, &if_true);
-
-      VisitForControl(expr->expression(), if_true, if_false);
-
+      PrepareTest(&materialize_true, &materialize_false,
+                  &if_false, &if_true, &fall_through);
+      VisitForControl(expr->expression(), if_true, if_false, fall_through);
       Apply(context_, if_false, if_true);  // Labels swapped.
       break;
     }
 
     case Token::TYPEOF: {
       Comment cmnt(masm_, "[ UnaryOperation (TYPEOF)");
-      VariableProxy* proxy = expr->expression()->AsVariableProxy();
-      if (proxy != NULL &&
-          !proxy->var()->is_this() &&
-          proxy->var()->is_global()) {
-        Comment cmnt(masm_, "Global variable");
-        __ Move(rcx, proxy->name());
-        __ movq(rax, CodeGenerator::GlobalObject());
-        Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
-        // Use a regular load, not a contextual load, to avoid a reference
-        // error.
-        __ Call(ic, RelocInfo::CODE_TARGET);
-        __ push(rax);
-      } else if (proxy != NULL &&
-                 proxy->var()->slot() != NULL &&
-                 proxy->var()->slot()->type() == Slot::LOOKUP) {
-        __ push(rsi);
-        __ Push(proxy->name());
-        __ CallRuntime(Runtime::kLoadContextSlotNoReferenceError, 2);
-        __ push(rax);
-      } else {
-        // This expression cannot throw a reference error at the top level.
-        VisitForValue(expr->expression(), kStack);
-      }
-
+      VisitForTypeofValue(expr->expression(), kStack);
       __ CallRuntime(Runtime::kTypeof, 1);
       Apply(context_, rax);
       break;
@@ -2906,9 +2774,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
     case Token::SUB: {
       Comment cmt(masm_, "[ UnaryOperation (SUB)");
-      bool can_overwrite =
-          (expr->expression()->AsBinaryOperation() != NULL &&
-           expr->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
+      bool can_overwrite = expr->expression()->ResultOverwriteAllowed();
       UnaryOverwriteMode overwrite =
           can_overwrite ? UNARY_OVERWRITE : UNARY_NO_OVERWRITE;
       GenericUnaryOpStub stub(Token::SUB, overwrite);
@@ -2922,27 +2788,24 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
     case Token::BIT_NOT: {
       Comment cmt(masm_, "[ UnaryOperation (BIT_NOT)");
-      bool can_overwrite =
-          (expr->expression()->AsBinaryOperation() != NULL &&
-           expr->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
-      UnaryOverwriteMode overwrite =
-          can_overwrite ? UNARY_OVERWRITE : UNARY_NO_OVERWRITE;
-      GenericUnaryOpStub stub(Token::BIT_NOT, overwrite);
-      // GenericUnaryOpStub expects the argument to be in the
-      // accumulator register rax.
+      // The generic unary operation stub expects the argument to be
+      // in the accumulator register rax.
       VisitForValue(expr->expression(), kAccumulator);
-      // Avoid calling the stub for Smis.
-      Label smi, done;
-      Condition is_smi = masm_->CheckSmi(result_register());
-      __ j(is_smi, &smi);
-      // Non-smi: call stub leaving result in accumulator register.
+      Label done;
+      if (ShouldInlineSmiCase(expr->op())) {
+        Label call_stub;
+        __ JumpIfNotSmi(rax, &call_stub);
+        __ SmiNot(rax, rax);
+        __ jmp(&done);
+        __ bind(&call_stub);
+      }
+      bool overwrite = expr->expression()->ResultOverwriteAllowed();
+      UnaryOverwriteMode mode =
+          overwrite ? UNARY_OVERWRITE : UNARY_NO_OVERWRITE;
+      GenericUnaryOpStub stub(Token::BIT_NOT, mode);
       __ CallStub(&stub);
-      __ jmp(&done);
-      // Perform operation directly on Smis.
-      __ bind(&smi);
-      __ SmiNot(result_register(), result_register());
       __ bind(&done);
-      Apply(context_, result_register());
+      Apply(context_, rax);
       break;
     }
 
@@ -2954,6 +2817,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
   Comment cmnt(masm_, "[ CountOperation");
+  SetSourcePosition(expr->position());
 
   // Invalid left-hand-sides are rewritten to have a 'throw
   // ReferenceError' as the left-hand side.
@@ -3019,8 +2883,6 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
         break;
       case Expression::kValue:
       case Expression::kTest:
-      case Expression::kValueTest:
-      case Expression::kTestValue:
         // Save the result on the stack. If we have a named or keyed property
         // we store the result under the receiver that is currently on top
         // of the stack.
@@ -3041,7 +2903,7 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
 
   // Inline smi case if we are in a loop.
   Label stub_call, done;
-  if (loop_depth() > 0) {
+  if (ShouldInlineSmiCase(expr->op())) {
     if (expr->op() == Token::INC) {
       __ SmiAddConstant(rax, rax, Smi::FromInt(1));
     } else {
@@ -3124,83 +2986,144 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
   }
 }
 
-void FullCodeGenerator::VisitBinaryOperation(BinaryOperation* expr) {
-  Comment cmnt(masm_, "[ BinaryOperation");
-  switch (expr->op()) {
-    case Token::COMMA:
-      VisitForEffect(expr->left());
-      Visit(expr->right());
-      break;
-
-    case Token::OR:
-    case Token::AND:
-      EmitLogicalOperation(expr);
-      break;
-
-    case Token::ADD:
-    case Token::SUB:
-    case Token::DIV:
-    case Token::MOD:
-    case Token::MUL:
-    case Token::BIT_OR:
-    case Token::BIT_AND:
-    case Token::BIT_XOR:
-    case Token::SHL:
-    case Token::SHR:
-    case Token::SAR:
-      VisitForValue(expr->left(), kStack);
-      VisitForValue(expr->right(), kAccumulator);
-      EmitBinaryOp(expr->op(), context_);
-      break;
-
-    default:
-      UNREACHABLE();
-  }
-}
-
 
-void FullCodeGenerator::EmitNullCompare(bool strict,
-                                        Register obj,
-                                        Register null_const,
-                                        Label* if_true,
-                                        Label* if_false,
-                                        Register scratch) {
-  __ cmpq(obj, null_const);
-  if (strict) {
-    __ j(equal, if_true);
+void FullCodeGenerator::VisitForTypeofValue(Expression* expr, Location where) {
+  VariableProxy* proxy = expr->AsVariableProxy();
+  if (proxy != NULL && !proxy->var()->is_this() && proxy->var()->is_global()) {
+    Comment cmnt(masm_, "Global variable");
+    __ Move(rcx, proxy->name());
+    __ movq(rax, CodeGenerator::GlobalObject());
+    Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
+    // Use a regular load, not a contextual load, to avoid a reference
+    // error.
+    __ Call(ic, RelocInfo::CODE_TARGET);
+    if (where == kStack) __ push(rax);
+  } else if (proxy != NULL &&
+             proxy->var()->slot() != NULL &&
+             proxy->var()->slot()->type() == Slot::LOOKUP) {
+    __ push(rsi);
+    __ Push(proxy->name());
+    __ CallRuntime(Runtime::kLoadContextSlotNoReferenceError, 2);
+    if (where == kStack) __ push(rax);
   } else {
+    // This expression cannot throw a reference error at the top level.
+    VisitForValue(expr, where);
+  }
+}
+
+
+bool FullCodeGenerator::TryLiteralCompare(Token::Value op,
+                                          Expression* left,
+                                          Expression* right,
+                                          Label* if_true,
+                                          Label* if_false,
+                                          Label* fall_through) {
+  if (op != Token::EQ && op != Token::EQ_STRICT) return false;
+
+  // Check for the pattern: typeof <expression> == <string literal>.
+  Literal* right_literal = right->AsLiteral();
+  if (right_literal == NULL) return false;
+  Handle<Object> right_literal_value = right_literal->handle();
+  if (!right_literal_value->IsString()) return false;
+  UnaryOperation* left_unary = left->AsUnaryOperation();
+  if (left_unary == NULL || left_unary->op() != Token::TYPEOF) return false;
+  Handle<String> check = Handle<String>::cast(right_literal_value);
+
+  VisitForTypeofValue(left_unary->expression(), kAccumulator);
+  if (check->Equals(Heap::number_symbol())) {
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_true);
+    __ movq(rax, FieldOperand(rax, HeapObject::kMapOffset));
+    __ CompareRoot(rax, Heap::kHeapNumberMapRootIndex);
+    Split(equal, if_true, if_false, fall_through);
+  } else if (check->Equals(Heap::string_symbol())) {
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_false);
+    // Check for undetectable objects => false.
+    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    __ j(not_zero, if_false);
+    __ CmpInstanceType(rdx, FIRST_NONSTRING_TYPE);
+    Split(below, if_true, if_false, fall_through);
+  } else if (check->Equals(Heap::boolean_symbol())) {
+    __ CompareRoot(rax, Heap::kTrueValueRootIndex);
     __ j(equal, if_true);
-    __ CompareRoot(obj, Heap::kUndefinedValueRootIndex);
+    __ CompareRoot(rax, Heap::kFalseValueRootIndex);
+    Split(equal, if_true, if_false, fall_through);
+  } else if (check->Equals(Heap::undefined_symbol())) {
+    __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
     __ j(equal, if_true);
-    __ JumpIfSmi(obj, if_false);
-    // It can be an undetectable object.
-    __ movq(scratch, FieldOperand(obj, HeapObject::kMapOffset));
-    __ testb(FieldOperand(scratch, Map::kBitFieldOffset),
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_false);
+    // Check for undetectable objects => true.
+    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    Split(not_zero, if_true, if_false, fall_through);
+  } else if (check->Equals(Heap::function_symbol())) {
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_false);
+    __ CmpObjectType(rax, JS_FUNCTION_TYPE, rdx);
+    __ j(equal, if_true);
+    // Regular expressions => 'function' (they are callable).
+    __ CmpInstanceType(rdx, JS_REGEXP_TYPE);
+    Split(equal, if_true, if_false, fall_through);
+  } else if (check->Equals(Heap::object_symbol())) {
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_false);
+    __ CompareRoot(rax, Heap::kNullValueRootIndex);
+    __ j(equal, if_true);
+    // Regular expressions => 'function', not 'object'.
+    __ CmpObjectType(rax, JS_REGEXP_TYPE, rdx);
+    __ j(equal, if_false);
+    // Check for undetectable objects => false.
+    __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
              Immediate(1 << Map::kIsUndetectable));
-    __ j(not_zero, if_true);
+    __ j(not_zero, if_false);
+    // Check for JS objects => true.
+    __ CmpInstanceType(rdx, FIRST_JS_OBJECT_TYPE);
+    __ j(below, if_false);
+    __ CmpInstanceType(rdx, LAST_JS_OBJECT_TYPE);
+    Split(below_equal, if_true, if_false, fall_through);
+  } else {
+    if (if_false != fall_through) __ jmp(if_false);
   }
-  __ jmp(if_false);
+
+  return true;
 }
 
 
 void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
   Comment cmnt(masm_, "[ CompareOperation");
+  SetSourcePosition(expr->position());
 
   // Always perform the comparison for its control flow.  Pack the result
   // into the expression's context after the comparison is performed.
   Label materialize_true, materialize_false;
   Label* if_true = NULL;
   Label* if_false = NULL;
-  PrepareTest(&materialize_true, &materialize_false, &if_true, &if_false);
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
+
+  // First we try a fast inlined version of the compare when one of
+  // the operands is a literal.
+  Token::Value op = expr->op();
+  Expression* left = expr->left();
+  Expression* right = expr->right();
+  if (TryLiteralCompare(op, left, right, if_true, if_false, fall_through)) {
+    Apply(context_, if_true, if_false);
+    return;
+  }
 
   VisitForValue(expr->left(), kStack);
-  switch (expr->op()) {
+  switch (op) {
     case Token::IN:
       VisitForValue(expr->right(), kStack);
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
       __ CompareRoot(rax, Heap::kTrueValueRootIndex);
-      __ j(equal, if_true);
-      __ jmp(if_false);
+      Split(equal, if_true, if_false, fall_through);
       break;
 
     case Token::INSTANCEOF: {
@@ -3208,8 +3131,8 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
       InstanceofStub stub;
       __ CallStub(&stub);
       __ testq(rax, rax);
-      __ j(zero, if_true);  // The stub returns 0 for true.
-      __ jmp(if_false);
+       // The stub returns 0 for true.
+      Split(zero, if_true, if_false, fall_through);
       break;
     }
 
@@ -3217,28 +3140,14 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
       VisitForValue(expr->right(), kAccumulator);
       Condition cc = no_condition;
       bool strict = false;
-      switch (expr->op()) {
+      switch (op) {
         case Token::EQ_STRICT:
           strict = true;
           // Fall through.
-        case Token::EQ: {
+        case Token::EQ:
           cc = equal;
           __ pop(rdx);
-          // If either operand is constant null we do a fast compare
-          // against null.
-          Literal* right_literal = expr->right()->AsLiteral();
-          Literal* left_literal = expr->left()->AsLiteral();
-          if (right_literal != NULL && right_literal->handle()->IsNull()) {
-            EmitNullCompare(strict, rdx, rax, if_true, if_false, rcx);
-            Apply(context_, if_true, if_false);
-            return;
-          } else if (left_literal != NULL && left_literal->handle()->IsNull()) {
-            EmitNullCompare(strict, rax, rdx, if_true, if_false, rcx);
-            Apply(context_, if_true, if_false);
-            return;
-          }
           break;
-        }
         case Token::LT:
           cc = less;
           __ pop(rdx);
@@ -3265,20 +3174,18 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
           UNREACHABLE();
       }
 
-      // The comparison stub expects the smi vs. smi case to be handled
-      // before it is called.
-      Label slow_case;
-      __ JumpIfNotBothSmi(rax, rdx, &slow_case);
-      __ SmiCompare(rdx, rax);
-      __ j(cc, if_true);
-      __ jmp(if_false);
+      if (ShouldInlineSmiCase(op)) {
+        Label slow_case;
+        __ JumpIfNotBothSmi(rax, rdx, &slow_case);
+        __ SmiCompare(rdx, rax);
+        Split(cc, if_true, if_false, NULL);
+        __ bind(&slow_case);
+      }
 
-      __ bind(&slow_case);
       CompareStub stub(cc, strict);
       __ CallStub(&stub);
       __ testq(rax, rax);
-      __ j(cc, if_true);
-      __ jmp(if_false);
+      Split(cc, if_true, if_false, fall_through);
     }
   }
 
@@ -3288,6 +3195,35 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
 }
 
 
+void FullCodeGenerator::VisitCompareToNull(CompareToNull* expr) {
+  Comment cmnt(masm_, "[ CompareToNull");
+  Label materialize_true, materialize_false;
+  Label* if_true = NULL;
+  Label* if_false = NULL;
+  Label* fall_through = NULL;
+  PrepareTest(&materialize_true, &materialize_false,
+              &if_true, &if_false, &fall_through);
+
+  VisitForValue(expr->expression(), kAccumulator);
+  __ CompareRoot(rax, Heap::kNullValueRootIndex);
+  if (expr->is_strict()) {
+    Split(equal, if_true, if_false, fall_through);
+  } else {
+    __ j(equal, if_true);
+    __ CompareRoot(rax, Heap::kUndefinedValueRootIndex);
+    __ j(equal, if_true);
+    Condition is_smi = masm_->CheckSmi(rax);
+    __ j(is_smi, if_false);
+    // It can be an undetectable object.
+    __ movq(rdx, FieldOperand(rax, HeapObject::kMapOffset));
+    __ testb(FieldOperand(rdx, Map::kBitFieldOffset),
+             Immediate(1 << Map::kIsUndetectable));
+    Split(not_zero, if_true, if_false, fall_through);
+  }
+  Apply(context_, if_true, if_false);
+}
+
+
 void FullCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
   Apply(context_, rax);
diff --git a/deps/v8/src/x64/ic-x64.cc b/deps/v8/src/x64/ic-x64.cc
index a8971f5b4a..a74e621e15 100644
--- a/deps/v8/src/x64/ic-x64.cc
+++ b/deps/v8/src/x64/ic-x64.cc
@@ -487,6 +487,7 @@ static void GenerateKeyedLoadReceiverCheck(MacroAssembler* masm,
 
 
 // Loads an indexed element from a fast case array.
+// If not_fast_array is NULL, doesn't perform the elements map check.
 static void GenerateFastArrayLoad(MacroAssembler* masm,
                                   Register receiver,
                                   Register key,
@@ -515,10 +516,14 @@ static void GenerateFastArrayLoad(MacroAssembler* masm,
   //   scratch - used to hold elements of the receiver and the loaded value.
 
   __ movq(elements, FieldOperand(receiver, JSObject::kElementsOffset));
-  // Check that the object is in fast mode (not dictionary).
-  __ CompareRoot(FieldOperand(elements, HeapObject::kMapOffset),
-                 Heap::kFixedArrayMapRootIndex);
-  __ j(not_equal, not_fast_array);
+  if (not_fast_array != NULL) {
+    // Check that the object is in fast mode and writable.
+    __ CompareRoot(FieldOperand(elements, HeapObject::kMapOffset),
+                   Heap::kFixedArrayMapRootIndex);
+    __ j(not_equal, not_fast_array);
+  } else {
+    __ AssertFastElements(elements);
+  }
   // Check that the key (index) is within bounds.
   __ SmiCompare(key, FieldOperand(elements, FixedArray::kLengthOffset));
   // Unsigned comparison rejects negative indices.
@@ -567,31 +572,6 @@ static void GenerateKeyStringCheck(MacroAssembler* masm,
 }
 
 
-// Picks out an array index from the hash field.
-static void GenerateIndexFromHash(MacroAssembler* masm,
-                                  Register key,
-                                  Register hash) {
-  // Register use:
-  //   key - holds the overwritten key on exit.
-  //   hash - holds the key's hash. Clobbered.
-
-  // The assert checks that the constants for the maximum number of digits
-  // for an array index cached in the hash field and the number of bits
-  // reserved for it does not conflict.
-  ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
-         (1 << String::kArrayIndexValueBits));
-  // We want the smi-tagged index in key. Even if we subsequently go to
-  // the slow case, converting the key to a smi is always valid.
-  // key: string key
-  // hash: key's hash field, including its array index value.
-  __ and_(hash, Immediate(String::kArrayIndexValueMask));
-  __ shr(hash, Immediate(String::kHashShift));
-  // Here we actually clobber the key which will be used if calling into
-  // runtime later. However as the new key is the numeric value of a string key
-  // there is no difference in using either key.
-  __ Integer32ToSmi(key, hash);
-}
-
 
 void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
@@ -611,13 +591,19 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   GenerateKeyedLoadReceiverCheck(
       masm, rdx, rcx, Map::kHasIndexedInterceptor, &slow);
 
+  // Check the "has fast elements" bit in the receiver's map which is
+  // now in rcx.
+  __ testb(FieldOperand(rcx, Map::kBitField2Offset),
+           Immediate(1 << Map::kHasFastElements));
+  __ j(zero, &check_pixel_array);
+
   GenerateFastArrayLoad(masm,
                         rdx,
                         rax,
                         rcx,
                         rbx,
                         rax,
-                        &check_pixel_array,
+                        NULL,
                         &slow);
   __ IncrementCounter(&Counters::keyed_load_generic_smi, 1);
   __ ret(0);
@@ -626,7 +612,7 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   // Check whether the elements object is a pixel array.
   // rdx: receiver
   // rax: key
-  // rcx: elements array
+  __ movq(rcx, FieldOperand(rdx, JSObject::kElementsOffset));
   __ SmiToInteger32(rbx, rax);  // Used on both directions of next branch.
   __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
                  Heap::kPixelArrayMapRootIndex);
@@ -732,7 +718,7 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   __ ret(0);
 
   __ bind(&index_string);
-  GenerateIndexFromHash(masm, rax, rbx);
+  __ IndexFromHash(rbx, rax);
   __ jmp(&index_smi);
 }
 
@@ -1012,7 +998,7 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm) {
   // rdx: JSObject
   // rcx: index
   __ movq(rbx, FieldOperand(rdx, JSObject::kElementsOffset));
-  // Check that the object is in fast mode (not dictionary).
+  // Check that the object is in fast mode and writable.
   __ CompareRoot(FieldOperand(rbx, HeapObject::kMapOffset),
                  Heap::kFixedArrayMapRootIndex);
   __ j(not_equal, &check_pixel_array);
@@ -1075,8 +1061,8 @@ void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm) {
   __ jmp(&fast);
 
   // Array case: Get the length and the elements array from the JS
-  // array. Check that the array is in fast mode; if it is the
-  // length is always a smi.
+  // array. Check that the array is in fast mode (and writable); if it
+  // is the length is always a smi.
   __ bind(&array);
   // rax: value
   // rdx: receiver (a JSArray)
@@ -1588,7 +1574,7 @@ void KeyedCallIC::GenerateMegamorphic(MacroAssembler* masm, int argc) {
   GenerateMiss(masm, argc);
 
   __ bind(&index_string);
-  GenerateIndexFromHash(masm, rcx, rbx);
+  __ IndexFromHash(rbx, rcx);
   // Now jump to the place where smi keys are handled.
   __ jmp(&index_smi);
 }
@@ -1862,6 +1848,8 @@ void StoreIC::GenerateArrayLength(MacroAssembler* masm) {
   __ j(not_equal, &miss);
 
   // Check that elements are FixedArray.
+  // We rely on StoreIC_ArrayLength below to deal with all types of
+  // fast elements (including COW).
   __ movq(scratch, FieldOperand(receiver, JSArray::kElementsOffset));
   __ CmpObjectType(scratch, FIXED_ARRAY_TYPE, scratch);
   __ j(not_equal, &miss);
diff --git a/deps/v8/src/x64/macro-assembler-x64.cc b/deps/v8/src/x64/macro-assembler-x64.cc
index c1954a898a..165c51dd27 100644
--- a/deps/v8/src/x64/macro-assembler-x64.cc
+++ b/deps/v8/src/x64/macro-assembler-x64.cc
@@ -262,6 +262,21 @@ void MacroAssembler::Assert(Condition cc, const char* msg) {
 }
 
 
+void MacroAssembler::AssertFastElements(Register elements) {
+  if (FLAG_debug_code) {
+    Label ok;
+    CompareRoot(FieldOperand(elements, HeapObject::kMapOffset),
+                Heap::kFixedArrayMapRootIndex);
+    j(equal, &ok);
+    CompareRoot(FieldOperand(elements, HeapObject::kMapOffset),
+                Heap::kFixedCOWArrayMapRootIndex);
+    j(equal, &ok);
+    Abort("JSObject with fast elements map has slow elements");
+    bind(&ok);
+  }
+}
+
+
 void MacroAssembler::Check(Condition cc, const char* msg) {
   Label L;
   j(cc, &L);
@@ -376,6 +391,25 @@ void MacroAssembler::IllegalOperation(int num_arguments) {
 }
 
 
+void MacroAssembler::IndexFromHash(Register hash, Register index) {
+  // The assert checks that the constants for the maximum number of digits
+  // for an array index cached in the hash field and the number of bits
+  // reserved for it does not conflict.
+  ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
+         (1 << String::kArrayIndexValueBits));
+  // We want the smi-tagged index in key. Even if we subsequently go to
+  // the slow case, converting the key to a smi is always valid.
+  // key: string key
+  // hash: key's hash field, including its array index value.
+  and_(hash, Immediate(String::kArrayIndexValueMask));
+  shr(hash, Immediate(String::kHashShift));
+  // Here we actually clobber the key which will be used if calling into
+  // runtime later. However as the new key is the numeric value of a string key
+  // there is no difference in using either key.
+  Integer32ToSmi(index, hash);
+}
+
+
 void MacroAssembler::CallRuntime(Runtime::FunctionId id, int num_arguments) {
   CallRuntime(Runtime::FunctionForId(id), num_arguments);
 }
@@ -566,28 +600,21 @@ void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag) {
 }
 
 
-void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
-  ASSERT(!target.is(rdi));
-
+void MacroAssembler::GetBuiltinFunction(Register target,
+                                        Builtins::JavaScript id) {
   // Load the builtins object into target register.
   movq(target, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
   movq(target, FieldOperand(target, GlobalObject::kBuiltinsOffset));
+  movq(target, FieldOperand(target,
+                            JSBuiltinsObject::OffsetOfFunctionWithId(id)));
+}
 
-  // Load the JavaScript builtin function from the builtins object.
-  movq(rdi, FieldOperand(target, JSBuiltinsObject::OffsetOfFunctionWithId(id)));
 
-  // Load the code entry point from the builtins object.
-  movq(target, FieldOperand(target, JSBuiltinsObject::OffsetOfCodeWithId(id)));
-  if (FLAG_debug_code) {
-    // Make sure the code objects in the builtins object and in the
-    // builtin function are the same.
-    push(target);
-    movq(target, FieldOperand(rdi, JSFunction::kCodeOffset));
-    cmpq(target, Operand(rsp, 0));
-    Assert(equal, "Builtin code object changed");
-    pop(target);
-  }
-  lea(target, FieldOperand(target, Code::kHeaderSize));
+void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
+  ASSERT(!target.is(rdi));
+  // Load the JavaScript builtin function from the builtins object.
+  GetBuiltinFunction(rdi, id);
+  movq(target, FieldOperand(rdi, JSFunction::kCodeEntryOffset));
 }
 
 
@@ -2094,91 +2121,8 @@ void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
   }
 }
 
-#ifdef ENABLE_DEBUGGER_SUPPORT
-
-void MacroAssembler::PushRegistersFromMemory(RegList regs) {
-  ASSERT((regs & ~kJSCallerSaved) == 0);
-  // Push the content of the memory location to the stack.
-  for (int i = 0; i < kNumJSCallerSaved; i++) {
-    int r = JSCallerSavedCode(i);
-    if ((regs & (1 << r)) != 0) {
-      ExternalReference reg_addr =
-          ExternalReference(Debug_Address::Register(i));
-      movq(kScratchRegister, reg_addr);
-      push(Operand(kScratchRegister, 0));
-    }
-  }
-}
-
-
-void MacroAssembler::SaveRegistersToMemory(RegList regs) {
-  ASSERT((regs & ~kJSCallerSaved) == 0);
-  // Copy the content of registers to memory location.
-  for (int i = 0; i < kNumJSCallerSaved; i++) {
-    int r = JSCallerSavedCode(i);
-    if ((regs & (1 << r)) != 0) {
-      Register reg = { r };
-      ExternalReference reg_addr =
-          ExternalReference(Debug_Address::Register(i));
-      movq(kScratchRegister, reg_addr);
-      movq(Operand(kScratchRegister, 0), reg);
-    }
-  }
-}
-
-
-void MacroAssembler::RestoreRegistersFromMemory(RegList regs) {
-  ASSERT((regs & ~kJSCallerSaved) == 0);
-  // Copy the content of memory location to registers.
-  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
-    int r = JSCallerSavedCode(i);
-    if ((regs & (1 << r)) != 0) {
-      Register reg = { r };
-      ExternalReference reg_addr =
-          ExternalReference(Debug_Address::Register(i));
-      movq(kScratchRegister, reg_addr);
-      movq(reg, Operand(kScratchRegister, 0));
-    }
-  }
-}
-
-
-void MacroAssembler::PopRegistersToMemory(RegList regs) {
-  ASSERT((regs & ~kJSCallerSaved) == 0);
-  // Pop the content from the stack to the memory location.
-  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
-    int r = JSCallerSavedCode(i);
-    if ((regs & (1 << r)) != 0) {
-      ExternalReference reg_addr =
-          ExternalReference(Debug_Address::Register(i));
-      movq(kScratchRegister, reg_addr);
-      pop(Operand(kScratchRegister, 0));
-    }
-  }
-}
-
-
-void MacroAssembler::CopyRegistersFromStackToMemory(Register base,
-                                                    Register scratch,
-                                                    RegList regs) {
-  ASSERT(!scratch.is(kScratchRegister));
-  ASSERT(!base.is(kScratchRegister));
-  ASSERT(!base.is(scratch));
-  ASSERT((regs & ~kJSCallerSaved) == 0);
-  // Copy the content of the stack to the memory location and adjust base.
-  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
-    int r = JSCallerSavedCode(i);
-    if ((regs & (1 << r)) != 0) {
-      movq(scratch, Operand(base, 0));
-      ExternalReference reg_addr =
-          ExternalReference(Debug_Address::Register(i));
-      movq(kScratchRegister, reg_addr);
-      movq(Operand(kScratchRegister, 0), scratch);
-      lea(base, Operand(base, kPointerSize));
-    }
-  }
-}
 
+#ifdef ENABLE_DEBUGGER_SUPPORT
 void MacroAssembler::DebugBreak() {
   ASSERT(allow_stub_calls());
   xor_(rax, rax);  // no arguments
@@ -2296,10 +2240,9 @@ void MacroAssembler::InvokeFunction(Register function,
   movq(rsi, FieldOperand(function, JSFunction::kContextOffset));
   movsxlq(rbx,
           FieldOperand(rdx, SharedFunctionInfo::kFormalParameterCountOffset));
-  movq(rdx, FieldOperand(rdi, JSFunction::kCodeOffset));
   // Advances rdx to the end of the Code object header, to the start of
   // the executable code.
-  lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
+  movq(rdx, FieldOperand(rdi, JSFunction::kCodeEntryOffset));
 
   ParameterCount expected(rbx);
   InvokeCode(rdx, expected, actual, flag);
@@ -2349,8 +2292,7 @@ void MacroAssembler::LeaveFrame(StackFrame::Type type) {
 }
 
 
-void MacroAssembler::EnterExitFramePrologue(ExitFrame::Mode mode,
-                                            bool save_rax) {
+void MacroAssembler::EnterExitFramePrologue(bool save_rax) {
   // Setup the frame structure on the stack.
   // All constants are relative to the frame pointer of the exit frame.
   ASSERT(ExitFrameConstants::kCallerSPDisplacement == +2 * kPointerSize);
@@ -2359,7 +2301,7 @@ void MacroAssembler::EnterExitFramePrologue(ExitFrame::Mode mode,
   push(rbp);
   movq(rbp, rsp);
 
-  // Reserve room for entry stack pointer and push the debug marker.
+  // Reserve room for entry stack pointer and push the code object.
   ASSERT(ExitFrameConstants::kSPOffset == -1 * kPointerSize);
   push(Immediate(0));  // Saved entry sp, patched before call.
   movq(kScratchRegister, CodeObject(), RelocInfo::EMBEDDED_OBJECT);
@@ -2378,23 +2320,8 @@ void MacroAssembler::EnterExitFramePrologue(ExitFrame::Mode mode,
   store_rax(context_address);
 }
 
-void MacroAssembler::EnterExitFrameEpilogue(ExitFrame::Mode mode,
-                                            int result_size,
+void MacroAssembler::EnterExitFrameEpilogue(int result_size,
                                             int argc) {
-#ifdef ENABLE_DEBUGGER_SUPPORT
-  // Save the state of all registers to the stack from the memory
-  // location. This is needed to allow nested break points.
-  if (mode == ExitFrame::MODE_DEBUG) {
-    // TODO(1243899): This should be symmetric to
-    // CopyRegistersFromStackToMemory() but it isn't! esp is assumed
-    // correct here, but computed for the other call. Very error
-    // prone! FIX THIS.  Actually there are deeper problems with
-    // register saving than this asymmetry (see the bug report
-    // associated with this issue).
-    PushRegistersFromMemory(kJSCallerSaved);
-  }
-#endif
-
 #ifdef _WIN64
   // Reserve space on stack for result and argument structures, if necessary.
   int result_stack_space = (result_size < 2) ? 0 : result_size * kPointerSize;
@@ -2423,48 +2350,35 @@ void MacroAssembler::EnterExitFrameEpilogue(ExitFrame::Mode mode,
 }
 
 
-void MacroAssembler::EnterExitFrame(ExitFrame::Mode mode, int result_size) {
-  EnterExitFramePrologue(mode, true);
+void MacroAssembler::EnterExitFrame(int result_size) {
+  EnterExitFramePrologue(true);
 
   // Setup argv in callee-saved register r12. It is reused in LeaveExitFrame,
   // so it must be retained across the C-call.
   int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
   lea(r12, Operand(rbp, r14, times_pointer_size, offset));
 
-  EnterExitFrameEpilogue(mode, result_size, 2);
+  EnterExitFrameEpilogue(result_size, 2);
 }
 
 
-void MacroAssembler::EnterApiExitFrame(ExitFrame::Mode mode,
-                                       int stack_space,
+void MacroAssembler::EnterApiExitFrame(int stack_space,
                                        int argc,
                                        int result_size) {
-  EnterExitFramePrologue(mode, false);
+  EnterExitFramePrologue(false);
 
   // Setup argv in callee-saved register r12. It is reused in LeaveExitFrame,
   // so it must be retained across the C-call.
   int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
   lea(r12, Operand(rbp, (stack_space * kPointerSize) + offset));
 
-  EnterExitFrameEpilogue(mode, result_size, argc);
+  EnterExitFrameEpilogue(result_size, argc);
 }
 
 
-void MacroAssembler::LeaveExitFrame(ExitFrame::Mode mode, int result_size) {
+void MacroAssembler::LeaveExitFrame(int result_size) {
   // Registers:
   // r12 : argv
-#ifdef ENABLE_DEBUGGER_SUPPORT
-  // Restore the memory copy of the registers by digging them out from
-  // the stack. This is needed to allow nested break points.
-  if (mode == ExitFrame::MODE_DEBUG) {
-    // It's okay to clobber register rbx below because we don't need
-    // the function pointer after this.
-    const int kCallerSavedSize = kNumJSCallerSaved * kPointerSize;
-    int kOffset = ExitFrameConstants::kCodeOffset - kCallerSavedSize;
-    lea(rbx, Operand(rbp, kOffset));
-    CopyRegistersFromStackToMemory(rbx, rcx, kJSCallerSaved);
-  }
-#endif
 
   // Get the return address from the stack and restore the frame pointer.
   movq(rcx, Operand(rbp, 1 * kPointerSize));
diff --git a/deps/v8/src/x64/macro-assembler-x64.h b/deps/v8/src/x64/macro-assembler-x64.h
index 7083224bdf..9f5a746581 100644
--- a/deps/v8/src/x64/macro-assembler-x64.h
+++ b/deps/v8/src/x64/macro-assembler-x64.h
@@ -132,13 +132,6 @@ class MacroAssembler: public Assembler {
   // ---------------------------------------------------------------------------
   // Debugger Support
 
-  void SaveRegistersToMemory(RegList regs);
-  void RestoreRegistersFromMemory(RegList regs);
-  void PushRegistersFromMemory(RegList regs);
-  void PopRegistersToMemory(RegList regs);
-  void CopyRegistersFromStackToMemory(Register base,
-                                      Register scratch,
-                                      RegList regs);
   void DebugBreak();
 #endif
 
@@ -161,17 +154,16 @@ class MacroAssembler: public Assembler {
   // debug mode. Expects the number of arguments in register rax and
   // sets up the number of arguments in register rdi and the pointer
   // to the first argument in register rsi.
-  void EnterExitFrame(ExitFrame::Mode mode, int result_size = 1);
+  void EnterExitFrame(int result_size = 1);
 
-  void EnterApiExitFrame(ExitFrame::Mode mode,
-                         int stack_space,
+  void EnterApiExitFrame(int stack_space,
                          int argc,
                          int result_size = 1);
 
   // Leave the current exit frame. Expects/provides the return value in
   // register rax:rdx (untouched) and the pointer to the first
   // argument in register rsi.
-  void LeaveExitFrame(ExitFrame::Mode mode, int result_size = 1);
+  void LeaveExitFrame(int result_size = 1);
 
 
   // ---------------------------------------------------------------------------
@@ -203,6 +195,9 @@ class MacroAssembler: public Assembler {
   // the unresolved list if the name does not resolve.
   void InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag);
 
+  // Store the function for the given builtin in the target register.
+  void GetBuiltinFunction(Register target, Builtins::JavaScript id);
+
   // Store the code object for the given builtin in the target register.
   void GetBuiltinEntry(Register target, Builtins::JavaScript id);
 
@@ -720,6 +715,12 @@ class MacroAssembler: public Assembler {
   // occurred.
   void IllegalOperation(int num_arguments);
 
+  // Picks out an array index from the hash field.
+  // Register use:
+  //   hash - holds the index's hash. Clobbered.
+  //   index - holds the overwritten index on exit.
+  void IndexFromHash(Register hash, Register index);
+
   // Find the function context up the context chain.
   void LoadContext(Register dst, int context_chain_length);
 
@@ -832,6 +833,8 @@ class MacroAssembler: public Assembler {
   // Use --debug_code to enable.
   void Assert(Condition cc, const char* msg);
 
+  void AssertFastElements(Register elements);
+
   // Like Assert(), but always enabled.
   void Check(Condition cc, const char* msg);
 
@@ -873,8 +876,8 @@ class MacroAssembler: public Assembler {
   void EnterFrame(StackFrame::Type type);
   void LeaveFrame(StackFrame::Type type);
 
-  void EnterExitFramePrologue(ExitFrame::Mode mode, bool save_rax);
-  void EnterExitFrameEpilogue(ExitFrame::Mode mode, int result_size, int argc);
+  void EnterExitFramePrologue(bool save_rax);
+  void EnterExitFrameEpilogue(int result_size, int argc);
 
   // Allocation support helpers.
   // Loads the top of new-space into the result register.
diff --git a/deps/v8/src/x64/regexp-macro-assembler-x64.cc b/deps/v8/src/x64/regexp-macro-assembler-x64.cc
index 80318648ea..91e2b449e0 100644
--- a/deps/v8/src/x64/regexp-macro-assembler-x64.cc
+++ b/deps/v8/src/x64/regexp-macro-assembler-x64.cc
@@ -32,11 +32,9 @@
 #include "serialize.h"
 #include "unicode.h"
 #include "log.h"
-#include "ast.h"
 #include "regexp-stack.h"
 #include "macro-assembler.h"
 #include "regexp-macro-assembler.h"
-#include "x64/macro-assembler-x64.h"
 #include "x64/regexp-macro-assembler-x64.h"
 
 namespace v8 {
diff --git a/deps/v8/src/x64/stub-cache-x64.cc b/deps/v8/src/x64/stub-cache-x64.cc
index 7aaeab793d..f500ce647e 100644
--- a/deps/v8/src/x64/stub-cache-x64.cc
+++ b/deps/v8/src/x64/stub-cache-x64.cc
@@ -31,9 +31,10 @@
 #if defined(V8_TARGET_ARCH_X64)
 
 #include "ic-inl.h"
+#include "code-stubs.h"
 #include "codegen-inl.h"
 #include "stub-cache.h"
-#include "macro-assembler-x64.h"
+#include "macro-assembler.h"
 
 namespace v8 {
 namespace internal {
@@ -1084,16 +1085,18 @@ Object* CallStubCompiler::CompileArrayPushCall(Object* object,
     __ movq(rax, FieldOperand(rdx, JSArray::kLengthOffset));
     __ ret((argc + 1) * kPointerSize);
   } else {
+    Label call_builtin;
+
     // Get the elements array of the object.
     __ movq(rbx, FieldOperand(rdx, JSArray::kElementsOffset));
 
-    // Check that the elements are in fast mode (not dictionary).
+    // Check that the elements are in fast mode and writable.
     __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
            Factory::fixed_array_map());
-    __ j(not_equal, &miss);
+    __ j(not_equal, &call_builtin);
 
     if (argc == 1) {  // Otherwise fall through to call builtin.
-      Label call_builtin, exit, with_write_barrier, attempt_to_grow_elements;
+      Label exit, with_write_barrier, attempt_to_grow_elements;
 
       // Get the array's length into rax and calculate new length.
       __ SmiToInteger32(rax, FieldOperand(rdx, JSArray::kLengthOffset));
@@ -1164,7 +1167,7 @@ Object* CallStubCompiler::CompileArrayPushCall(Object* object,
       // Push the argument...
       __ movq(Operand(rdx, 0), rcx);
       // ... and fill the rest with holes.
-      __ Move(kScratchRegister, Factory::the_hole_value());
+      __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
       for (int i = 1; i < kAllocationDelta; i++) {
         __ movq(Operand(rdx, i * kPointerSize), kScratchRegister);
       }
@@ -1175,15 +1178,16 @@ Object* CallStubCompiler::CompileArrayPushCall(Object* object,
       // Increment element's and array's sizes.
       __ SmiAddConstant(FieldOperand(rbx, FixedArray::kLengthOffset),
                         Smi::FromInt(kAllocationDelta));
+
       // Make new length a smi before returning it.
       __ Integer32ToSmi(rax, rax);
       __ movq(FieldOperand(rdx, JSArray::kLengthOffset), rax);
+
       // Elements are in new space, so write barrier is not required.
       __ ret((argc + 1) * kPointerSize);
-
-      __ bind(&call_builtin);
     }
 
+    __ bind(&call_builtin);
     __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPush),
                                  argc + 1,
                                  1);
@@ -1204,11 +1208,11 @@ Object* CallStubCompiler::CompileArrayPopCall(Object* object,
                                               String* name,
                                               CheckType check) {
   // ----------- S t a t e -------------
-  //  -- ecx                 : name
-  //  -- esp[0]              : return address
-  //  -- esp[(argc - n) * 4] : arg[n] (zero-based)
+  //  -- rcx                 : name
+  //  -- rsp[0]              : return address
+  //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
-  //  -- esp[(argc + 1) * 4] : receiver
+  //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
   ASSERT(check == RECEIVER_MAP_CHECK);
 
@@ -1235,9 +1239,10 @@ Object* CallStubCompiler::CompileArrayPopCall(Object* object,
   // Get the elements array of the object.
   __ movq(rbx, FieldOperand(rdx, JSArray::kElementsOffset));
 
-  // Check that the elements are in fast mode (not dictionary).
-  __ Cmp(FieldOperand(rbx, HeapObject::kMapOffset), Factory::fixed_array_map());
-  __ j(not_equal, &miss);
+  // Check that the elements are in fast mode and writable.
+  __ CompareRoot(FieldOperand(rbx, HeapObject::kMapOffset),
+                 Heap::kFixedArrayMapRootIndex);
+  __ j(not_equal, &call_builtin);
 
   // Get the array's length into rcx and calculate new length.
   __ SmiToInteger32(rcx, FieldOperand(rdx, JSArray::kLengthOffset));
@@ -1245,7 +1250,7 @@ Object* CallStubCompiler::CompileArrayPopCall(Object* object,
   __ j(negative, &return_undefined);
 
   // Get the last element.
-  __ Move(r9, Factory::the_hole_value());
+  __ LoadRoot(r9, Heap::kTheHoleValueRootIndex);
   __ movq(rax, FieldOperand(rbx,
                             rcx, times_pointer_size,
                             FixedArray::kHeaderSize));
@@ -1265,14 +1270,14 @@ Object* CallStubCompiler::CompileArrayPopCall(Object* object,
   __ ret((argc + 1) * kPointerSize);
 
   __ bind(&return_undefined);
-
-  __ Move(rax, Factory::undefined_value());
+  __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
   __ ret((argc + 1) * kPointerSize);
 
   __ bind(&call_builtin);
   __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPop),
                                argc + 1,
                                1);
+
   __ bind(&miss);
   Object* obj = GenerateMissBranch();
   if (obj->IsFailure()) return obj;
@@ -1287,8 +1292,69 @@ Object* CallStubCompiler::CompileStringCharAtCall(Object* object,
                                                   JSFunction* function,
                                                   String* name,
                                                   CheckType check) {
-  // TODO(722): implement this.
-  return Heap::undefined_value();
+  // ----------- S t a t e -------------
+  //  -- rcx                 : function name
+  //  -- rsp[0]              : return address
+  //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
+  //  -- ...
+  //  -- rsp[(argc + 1) * 8] : receiver
+  // -----------------------------------
+
+  // If object is not a string, bail out to regular call.
+  if (!object->IsString()) return Heap::undefined_value();
+
+  const int argc = arguments().immediate();
+
+  Label miss;
+  Label index_out_of_range;
+
+  GenerateNameCheck(name, &miss);
+
+  // Check that the maps starting from the prototype haven't changed.
+  GenerateDirectLoadGlobalFunctionPrototype(masm(),
+                                            Context::STRING_FUNCTION_INDEX,
+                                            rax);
+  ASSERT(object != holder);
+  CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
+                  rbx, rdx, rdi, name, &miss);
+
+  Register receiver = rax;
+  Register index = rdi;
+  Register scratch1 = rbx;
+  Register scratch2 = rdx;
+  Register result = rax;
+  __ movq(receiver, Operand(rsp, (argc + 1) * kPointerSize));
+  if (argc > 0) {
+    __ movq(index, Operand(rsp, (argc - 0) * kPointerSize));
+  } else {
+    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
+  }
+
+  StringCharAtGenerator char_at_generator(receiver,
+                                          index,
+                                          scratch1,
+                                          scratch2,
+                                          result,
+                                          &miss,  // When not a string.
+                                          &miss,  // When not a number.
+                                          &index_out_of_range,
+                                          STRING_INDEX_IS_NUMBER);
+  char_at_generator.GenerateFast(masm());
+  __ ret((argc + 1) * kPointerSize);
+
+  ICRuntimeCallHelper call_helper;
+  char_at_generator.GenerateSlow(masm(), call_helper);
+
+  __ bind(&index_out_of_range);
+  __ LoadRoot(rax, Heap::kEmptyStringRootIndex);
+  __ ret((argc + 1) * kPointerSize);
+
+  __ bind(&miss);
+  Object* obj = GenerateMissBranch();
+  if (obj->IsFailure()) return obj;
+
+  // Return the generated code.
+  return GetCode(function);
 }
 
 
@@ -1297,10 +1363,67 @@ Object* CallStubCompiler::CompileStringCharCodeAtCall(Object* object,
                                                       JSFunction* function,
                                                       String* name,
                                                       CheckType check) {
-  // TODO(722): implement this.
-  return Heap::undefined_value();
-}
+  // ----------- S t a t e -------------
+  //  -- rcx                 : function name
+  //  -- rsp[0]              : return address
+  //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
+  //  -- ...
+  //  -- rsp[(argc + 1) * 8] : receiver
+  // -----------------------------------
+
+  // If object is not a string, bail out to regular call.
+  if (!object->IsString()) return Heap::undefined_value();
+
+  const int argc = arguments().immediate();
+
+  Label miss;
+  Label index_out_of_range;
+  GenerateNameCheck(name, &miss);
+
+  // Check that the maps starting from the prototype haven't changed.
+  GenerateDirectLoadGlobalFunctionPrototype(masm(),
+                                            Context::STRING_FUNCTION_INDEX,
+                                            rax);
+  ASSERT(object != holder);
+  CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
+                  rbx, rdx, rdi, name, &miss);
+
+  Register receiver = rbx;
+  Register index = rdi;
+  Register scratch = rdx;
+  Register result = rax;
+  __ movq(receiver, Operand(rsp, (argc + 1) * kPointerSize));
+  if (argc > 0) {
+    __ movq(index, Operand(rsp, (argc - 0) * kPointerSize));
+  } else {
+    __ LoadRoot(index, Heap::kUndefinedValueRootIndex);
+  }
 
+  StringCharCodeAtGenerator char_code_at_generator(receiver,
+                                                   index,
+                                                   scratch,
+                                                   result,
+                                                   &miss,  // When not a string.
+                                                   &miss,  // When not a number.
+                                                   &index_out_of_range,
+                                                   STRING_INDEX_IS_NUMBER);
+  char_code_at_generator.GenerateFast(masm());
+  __ ret((argc + 1) * kPointerSize);
+
+  ICRuntimeCallHelper call_helper;
+  char_code_at_generator.GenerateSlow(masm(), call_helper);
+
+  __ bind(&index_out_of_range);
+  __ LoadRoot(rax, Heap::kNanValueRootIndex);
+  __ ret((argc + 1) * kPointerSize);
+
+  __ bind(&miss);
+  Object* obj = GenerateMissBranch();
+  if (obj->IsFailure()) return obj;
+
+  // Return the generated code.
+  return GetCode(function);
+}
 
 
 Object* CallStubCompiler::CompileCallInterceptor(JSObject* object,
diff --git a/deps/v8/src/x64/virtual-frame-x64.cc b/deps/v8/src/x64/virtual-frame-x64.cc
index b8b008c7a6..88e7cc8811 100644
--- a/deps/v8/src/x64/virtual-frame-x64.cc
+++ b/deps/v8/src/x64/virtual-frame-x64.cc
@@ -1230,9 +1230,9 @@ Result VirtualFrame::CallConstructor(int arg_count) {
   // and receiver on the stack.
   Handle<Code> ic(Builtins::builtin(Builtins::JSConstructCall));
   // Duplicate the function before preparing the frame.
-  PushElementAt(arg_count + 1);
+  PushElementAt(arg_count);
   Result function = Pop();
-  PrepareForCall(arg_count + 1, arg_count + 1);  // Spill args and receiver.
+  PrepareForCall(arg_count + 1, arg_count + 1);  // Spill function and args.
   function.ToRegister(rdi);
 
   // Constructors are called with the number of arguments in register