Upgrade V8 to 3.4.10

1 files changed, 195 insertions, 330 deletions

diff --git a/deps/v8/src/x64/assembler-x64.cc b/deps/v8/src/x64/assembler-x64.cc
index 35c05b3ac3..745fdaeb8f 100644
--- a/deps/v8/src/x64/assembler-x64.cc
+++ b/deps/v8/src/x64/assembler-x64.cc
@@ -38,21 +38,38 @@ namespace internal {
 // -----------------------------------------------------------------------------
 // Implementation of CpuFeatures
 
-// The required user mode extensions in X64 are (from AMD64 ABI Table A.1):
-//   fpu, tsc, cx8, cmov, mmx, sse, sse2, fxsr, syscall
-uint64_t CpuFeatures::supported_ = kDefaultCpuFeatures;
-uint64_t CpuFeatures::enabled_ = 0;
+
+#ifdef DEBUG
+bool CpuFeatures::initialized_ = false;
+#endif
+uint64_t CpuFeatures::supported_ = CpuFeatures::kDefaultCpuFeatures;
 uint64_t CpuFeatures::found_by_runtime_probing_ = 0;
 
-void CpuFeatures::Probe(bool portable)  {
-  ASSERT(Heap::HasBeenSetup());
+
+void CpuFeatures::Probe() {
+  ASSERT(!initialized_);
+#ifdef DEBUG
+  initialized_ = true;
+#endif
   supported_ = kDefaultCpuFeatures;
-  if (portable && Serializer::enabled()) {
+  if (Serializer::enabled()) {
     supported_ |= OS::CpuFeaturesImpliedByPlatform();
     return;  // No features if we might serialize.
   }
 
-  Assembler assm(NULL, 0);
+  const int kBufferSize = 4 * KB;
+  VirtualMemory* memory = new VirtualMemory(kBufferSize);
+  if (!memory->IsReserved()) {
+    delete memory;
+    return;
+  }
+  ASSERT(memory->size() >= static_cast<size_t>(kBufferSize));
+  if (!memory->Commit(memory->address(), kBufferSize, true/*executable*/)) {
+    delete memory;
+    return;
+  }
+
+  Assembler assm(NULL, memory->address(), kBufferSize);
   Label cpuid, done;
 #define __ assm.
   // Save old rsp, since we are going to modify the stack.
@@ -82,7 +99,7 @@ void CpuFeatures::Probe(bool portable)  {
   // ecx:edx. Temporarily enable CPUID support because we know it's
   // safe here.
   __ bind(&cpuid);
-  __ movq(rax, Immediate(1));
+  __ movl(rax, Immediate(1));
   supported_ = kDefaultCpuFeatures | (1 << CPUID);
   { Scope fscope(CPUID);
     __ cpuid();
@@ -116,28 +133,20 @@ void CpuFeatures::Probe(bool portable)  {
   __ ret(0);
 #undef __
 
-  CodeDesc desc;
-  assm.GetCode(&desc);
-  MaybeObject* maybe_code = Heap::CreateCode(desc,
-                                             Code::ComputeFlags(Code::STUB),
-                                             Handle<Object>());
-  Object* code;
-  if (!maybe_code->ToObject(&code)) return;
-  if (!code->IsCode()) return;
-  PROFILE(CodeCreateEvent(Logger::BUILTIN_TAG,
-                          Code::cast(code), "CpuFeatures::Probe"));
   typedef uint64_t (*F0)();
-  F0 probe = FUNCTION_CAST<F0>(Code::cast(code)->entry());
+  F0 probe = FUNCTION_CAST<F0>(reinterpret_cast<Address>(memory->address()));
   supported_ = probe();
   found_by_runtime_probing_ = supported_;
   found_by_runtime_probing_ &= ~kDefaultCpuFeatures;
   uint64_t os_guarantees = OS::CpuFeaturesImpliedByPlatform();
   supported_ |= os_guarantees;
-  found_by_runtime_probing_ &= portable ? ~os_guarantees : 0;
+  found_by_runtime_probing_ &= ~os_guarantees;
   // SSE2 and CMOV must be available on an X64 CPU.
   ASSERT(IsSupported(CPUID));
   ASSERT(IsSupported(SSE2));
   ASSERT(IsSupported(CMOV));
+
+  delete memory;
 }
 
 
@@ -191,12 +200,12 @@ void RelocInfo::PatchCode(byte* instructions, int instruction_count) {
 // Register constants.
 
 const int Register::kRegisterCodeByAllocationIndex[kNumAllocatableRegisters] = {
-  // rax, rbx, rdx, rcx, rdi, r8, r9, r11, r14, r12
-  0, 3, 2, 1, 7, 8, 9, 11, 14, 12
+  // rax, rbx, rdx, rcx, rdi, r8, r9, r11, r14, r15
+  0, 3, 2, 1, 7, 8, 9, 11, 14, 15
 };
 
 const int Register::kAllocationIndexByRegisterCode[kNumRegisters] = {
-  0, 3, 2, 1, -1, -1, -1, 4, 5, 6, -1, 7, 9, -1, 8, -1
+  0, 3, 2, 1, -1, -1, -1, 4, 5, 6, -1, 7, -1, -1, 8, 9
 };
 
 
@@ -335,18 +344,19 @@ bool Operand::AddressUsesRegister(Register reg) const {
 static void InitCoverageLog();
 #endif
 
-byte* Assembler::spare_buffer_ = NULL;
-
-Assembler::Assembler(void* buffer, int buffer_size)
-    : code_targets_(100), positions_recorder_(this) {
+Assembler::Assembler(Isolate* arg_isolate, void* buffer, int buffer_size)
+    : AssemblerBase(arg_isolate),
+      code_targets_(100),
+      positions_recorder_(this),
+      emit_debug_code_(FLAG_debug_code) {
   if (buffer == NULL) {
     // Do our own buffer management.
     if (buffer_size <= kMinimalBufferSize) {
       buffer_size = kMinimalBufferSize;
 
-      if (spare_buffer_ != NULL) {
-        buffer = spare_buffer_;
-        spare_buffer_ = NULL;
+      if (isolate() != NULL && isolate()->assembler_spare_buffer() != NULL) {
+        buffer = isolate()->assembler_spare_buffer();
+        isolate()->set_assembler_spare_buffer(NULL);
       }
     }
     if (buffer == NULL) {
@@ -378,7 +388,6 @@ Assembler::Assembler(void* buffer, int buffer_size)
   pc_ = buffer_;
   reloc_info_writer.Reposition(buffer_ + buffer_size, pc_);
 
-  last_pc_ = NULL;
 
 #ifdef GENERATED_CODE_COVERAGE
   InitCoverageLog();
@@ -388,8 +397,10 @@ Assembler::Assembler(void* buffer, int buffer_size)
 
 Assembler::~Assembler() {
   if (own_buffer_) {
-    if (spare_buffer_ == NULL && buffer_size_ == kMinimalBufferSize) {
-      spare_buffer_ = buffer_;
+    if (isolate() != NULL &&
+        isolate()->assembler_spare_buffer() == NULL &&
+        buffer_size_ == kMinimalBufferSize) {
+      isolate()->set_assembler_spare_buffer(buffer_);
     } else {
       DeleteArray(buffer_);
     }
@@ -409,8 +420,6 @@ void Assembler::GetCode(CodeDesc* desc) {
   desc->reloc_size =
       static_cast<int>((buffer_ + buffer_size_) - reloc_info_writer.pos());
   desc->origin = this;
-
-  Counters::reloc_info_size.Increment(desc->reloc_size);
 }
 
 
@@ -434,7 +443,6 @@ void Assembler::CodeTargetAlign() {
 
 void Assembler::bind_to(Label* L, int pos) {
   ASSERT(!L->is_bound());  // Label may only be bound once.
-  last_pc_ = NULL;
   ASSERT(0 <= pos && pos <= pc_offset());  // Position must be valid.
   if (L->is_linked()) {
     int current = L->pos();
@@ -450,6 +458,20 @@ void Assembler::bind_to(Label* L, int pos) {
     int last_imm32 = pos - (current + sizeof(int32_t));
     long_at_put(current, last_imm32);
   }
+  while (L->is_near_linked()) {
+    int fixup_pos = L->near_link_pos();
+    int offset_to_next =
+        static_cast<int>(*reinterpret_cast<int8_t*>(addr_at(fixup_pos)));
+    ASSERT(offset_to_next <= 0);
+    int disp = pos - (fixup_pos + sizeof(int8_t));
+    ASSERT(is_int8(disp));
+    set_byte_at(fixup_pos, disp);
+    if (offset_to_next < 0) {
+      L->link_to(fixup_pos + offset_to_next, Label::kNear);
+    } else {
+      L->UnuseNear();
+    }
+  }
   L->bind_to(pos);
 }
 
@@ -459,20 +481,6 @@ void Assembler::bind(Label* L) {
 }
 
 
-void Assembler::bind(NearLabel* L) {
-  ASSERT(!L->is_bound());
-  last_pc_ = NULL;
-  while (L->unresolved_branches_ > 0) {
-    int branch_pos = L->unresolved_positions_[L->unresolved_branches_ - 1];
-    int disp = pc_offset() - branch_pos;
-    ASSERT(is_int8(disp));
-    set_byte_at(branch_pos - sizeof(int8_t), disp);
-    L->unresolved_branches_--;
-  }
-  L->bind_to(pc_offset());
-}
-
-
 void Assembler::GrowBuffer() {
   ASSERT(buffer_overflow());
   if (!own_buffer_) FATAL("external code buffer is too small");
@@ -487,7 +495,7 @@ void Assembler::GrowBuffer() {
   // Some internal data structures overflow for very large buffers,
   // they must ensure that kMaximalBufferSize is not too large.
   if ((desc.buffer_size > kMaximalBufferSize) ||
-      (desc.buffer_size > Heap::MaxOldGenerationSize())) {
+      (desc.buffer_size > HEAP->MaxOldGenerationSize())) {
     V8::FatalProcessOutOfMemory("Assembler::GrowBuffer");
   }
 
@@ -512,17 +520,16 @@ void Assembler::GrowBuffer() {
           reloc_info_writer.pos(), desc.reloc_size);
 
   // Switch buffers.
-  if (spare_buffer_ == NULL && buffer_size_ == kMinimalBufferSize) {
-    spare_buffer_ = buffer_;
+  if (isolate() != NULL &&
+      isolate()->assembler_spare_buffer() == NULL &&
+      buffer_size_ == kMinimalBufferSize) {
+    isolate()->set_assembler_spare_buffer(buffer_);
   } else {
     DeleteArray(buffer_);
   }
   buffer_ = desc.buffer;
   buffer_size_ = desc.buffer_size;
   pc_ += pc_delta;
-  if (last_pc_ != NULL) {
-    last_pc_ += pc_delta;
-  }
   reloc_info_writer.Reposition(reloc_info_writer.pos() + rc_delta,
                                reloc_info_writer.last_pc() + pc_delta);
 
@@ -560,7 +567,6 @@ void Assembler::emit_operand(int code, const Operand& adr) {
 
 void Assembler::arithmetic_op(byte opcode, Register reg, const Operand& op) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(reg, op);
   emit(opcode);
   emit_operand(reg, op);
@@ -569,7 +575,6 @@ void Assembler::arithmetic_op(byte opcode, Register reg, const Operand& op) {
 
 void Assembler::arithmetic_op(byte opcode, Register reg, Register rm_reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT((opcode & 0xC6) == 2);
   if (rm_reg.low_bits() == 4)  {  // Forces SIB byte.
     // Swap reg and rm_reg and change opcode operand order.
@@ -586,7 +591,6 @@ void Assembler::arithmetic_op(byte opcode, Register reg, Register rm_reg) {
 
 void Assembler::arithmetic_op_16(byte opcode, Register reg, Register rm_reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT((opcode & 0xC6) == 2);
   if (rm_reg.low_bits() == 4) {  // Forces SIB byte.
     // Swap reg and rm_reg and change opcode operand order.
@@ -607,7 +611,6 @@ void Assembler::arithmetic_op_16(byte opcode,
                                  Register reg,
                                  const Operand& rm_reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(reg, rm_reg);
   emit(opcode);
@@ -617,7 +620,6 @@ void Assembler::arithmetic_op_16(byte opcode,
 
 void Assembler::arithmetic_op_32(byte opcode, Register reg, Register rm_reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT((opcode & 0xC6) == 2);
   if (rm_reg.low_bits() == 4) {  // Forces SIB byte.
     // Swap reg and rm_reg and change opcode operand order.
@@ -636,7 +638,6 @@ void Assembler::arithmetic_op_32(byte opcode,
                                  Register reg,
                                  const Operand& rm_reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(reg, rm_reg);
   emit(opcode);
   emit_operand(reg, rm_reg);
@@ -647,7 +648,6 @@ void Assembler::immediate_arithmetic_op(byte subcode,
                                         Register dst,
                                         Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   if (is_int8(src.value_)) {
     emit(0x83);
@@ -667,7 +667,6 @@ void Assembler::immediate_arithmetic_op(byte subcode,
                                         const Operand& dst,
                                         Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   if (is_int8(src.value_)) {
     emit(0x83);
@@ -685,7 +684,6 @@ void Assembler::immediate_arithmetic_op_16(byte subcode,
                                            Register dst,
                                            Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);  // Operand size override prefix.
   emit_optional_rex_32(dst);
   if (is_int8(src.value_)) {
@@ -707,7 +705,6 @@ void Assembler::immediate_arithmetic_op_16(byte subcode,
                                            const Operand& dst,
                                            Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);  // Operand size override prefix.
   emit_optional_rex_32(dst);
   if (is_int8(src.value_)) {
@@ -726,7 +723,6 @@ void Assembler::immediate_arithmetic_op_32(byte subcode,
                                            Register dst,
                                            Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   if (is_int8(src.value_)) {
     emit(0x83);
@@ -747,7 +743,6 @@ void Assembler::immediate_arithmetic_op_32(byte subcode,
                                            const Operand& dst,
                                            Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   if (is_int8(src.value_)) {
     emit(0x83);
@@ -765,7 +760,6 @@ void Assembler::immediate_arithmetic_op_8(byte subcode,
                                           const Operand& dst,
                                           Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   ASSERT(is_int8(src.value_) || is_uint8(src.value_));
   emit(0x80);
@@ -778,7 +772,6 @@ void Assembler::immediate_arithmetic_op_8(byte subcode,
                                           Register dst,
                                           Immediate src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (dst.code() > 3) {
     // Use 64-bit mode byte registers.
     emit_rex_64(dst);
@@ -792,7 +785,6 @@ void Assembler::immediate_arithmetic_op_8(byte subcode,
 
 void Assembler::shift(Register dst, Immediate shift_amount, int subcode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint6(shift_amount.value_));  // illegal shift count
   if (shift_amount.value_ == 1) {
     emit_rex_64(dst);
@@ -809,7 +801,6 @@ void Assembler::shift(Register dst, Immediate shift_amount, int subcode) {
 
 void Assembler::shift(Register dst, int subcode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xD3);
   emit_modrm(subcode, dst);
@@ -818,7 +809,6 @@ void Assembler::shift(Register dst, int subcode) {
 
 void Assembler::shift_32(Register dst, int subcode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xD3);
   emit_modrm(subcode, dst);
@@ -827,7 +817,6 @@ void Assembler::shift_32(Register dst, int subcode) {
 
 void Assembler::shift_32(Register dst, Immediate shift_amount, int subcode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint5(shift_amount.value_));  // illegal shift count
   if (shift_amount.value_ == 1) {
     emit_optional_rex_32(dst);
@@ -844,7 +833,6 @@ void Assembler::shift_32(Register dst, Immediate shift_amount, int subcode) {
 
 void Assembler::bt(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src, dst);
   emit(0x0F);
   emit(0xA3);
@@ -854,7 +842,6 @@ void Assembler::bt(const Operand& dst, Register src) {
 
 void Assembler::bts(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src, dst);
   emit(0x0F);
   emit(0xAB);
@@ -865,7 +852,6 @@ void Assembler::bts(const Operand& dst, Register src) {
 void Assembler::call(Label* L) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // 1110 1000 #32-bit disp.
   emit(0xE8);
   if (L->is_bound()) {
@@ -884,20 +870,20 @@ void Assembler::call(Label* L) {
 }
 
 
-void Assembler::call(Handle<Code> target, RelocInfo::Mode rmode) {
+void Assembler::call(Handle<Code> target,
+                     RelocInfo::Mode rmode,
+                     unsigned ast_id) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // 1110 1000 #32-bit disp.
   emit(0xE8);
-  emit_code_target(target, rmode);
+  emit_code_target(target, rmode, ast_id);
 }
 
 
 void Assembler::call(Register adr) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: FF /2 r64.
   emit_optional_rex_32(adr);
   emit(0xFF);
@@ -908,7 +894,6 @@ void Assembler::call(Register adr) {
 void Assembler::call(const Operand& op) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: FF /2 m64.
   emit_optional_rex_32(op);
   emit(0xFF);
@@ -923,7 +908,6 @@ void Assembler::call(const Operand& op) {
 void Assembler::call(Address target) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // 1110 1000 #32-bit disp.
   emit(0xE8);
   Address source = pc_ + 4;
@@ -935,13 +919,16 @@ void Assembler::call(Address target) {
 
 void Assembler::clc() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF8);
 }
 
+void Assembler::cld() {
+  EnsureSpace ensure_space(this);
+  emit(0xFC);
+}
+
 void Assembler::cdq() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x99);
 }
 
@@ -956,7 +943,6 @@ void Assembler::cmovq(Condition cc, Register dst, Register src) {
   // 64-bit architecture.
   ASSERT(cc >= 0);  // Use mov for unconditional moves.
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: REX.W 0f 40 + cc /r.
   emit_rex_64(dst, src);
   emit(0x0f);
@@ -973,7 +959,6 @@ void Assembler::cmovq(Condition cc, Register dst, const Operand& src) {
   }
   ASSERT(cc >= 0);
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: REX.W 0f 40 + cc /r.
   emit_rex_64(dst, src);
   emit(0x0f);
@@ -990,7 +975,6 @@ void Assembler::cmovl(Condition cc, Register dst, Register src) {
   }
   ASSERT(cc >= 0);
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: 0f 40 + cc /r.
   emit_optional_rex_32(dst, src);
   emit(0x0f);
@@ -1007,7 +991,6 @@ void Assembler::cmovl(Condition cc, Register dst, const Operand& src) {
   }
   ASSERT(cc >= 0);
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode: 0f 40 + cc /r.
   emit_optional_rex_32(dst, src);
   emit(0x0f);
@@ -1019,7 +1002,6 @@ void Assembler::cmovl(Condition cc, Register dst, const Operand& src) {
 void Assembler::cmpb_al(Immediate imm8) {
   ASSERT(is_int8(imm8.value_) || is_uint8(imm8.value_));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x3c);
   emit(imm8.value_);
 }
@@ -1028,7 +1010,6 @@ void Assembler::cmpb_al(Immediate imm8) {
 void Assembler::cpuid() {
   ASSERT(CpuFeatures::IsEnabled(CPUID));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x0F);
   emit(0xA2);
 }
@@ -1036,7 +1017,6 @@ void Assembler::cpuid() {
 
 void Assembler::cqo() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64();
   emit(0x99);
 }
@@ -1044,7 +1024,6 @@ void Assembler::cqo() {
 
 void Assembler::decq(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xFF);
   emit_modrm(0x1, dst);
@@ -1053,7 +1032,6 @@ void Assembler::decq(Register dst) {
 
 void Assembler::decq(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xFF);
   emit_operand(1, dst);
@@ -1062,7 +1040,6 @@ void Assembler::decq(const Operand& dst) {
 
 void Assembler::decl(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xFF);
   emit_modrm(0x1, dst);
@@ -1071,7 +1048,6 @@ void Assembler::decl(Register dst) {
 
 void Assembler::decl(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xFF);
   emit_operand(1, dst);
@@ -1080,7 +1056,6 @@ void Assembler::decl(const Operand& dst) {
 
 void Assembler::decb(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (dst.code() > 3) {
     // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
     emit_rex_32(dst);
@@ -1092,7 +1067,6 @@ void Assembler::decb(Register dst) {
 
 void Assembler::decb(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xFE);
   emit_operand(1, dst);
@@ -1101,7 +1075,6 @@ void Assembler::decb(const Operand& dst) {
 
 void Assembler::enter(Immediate size) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xC8);
   emitw(size.value_);  // 16 bit operand, always.
   emit(0);
@@ -1110,14 +1083,12 @@ void Assembler::enter(Immediate size) {
 
 void Assembler::hlt() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF4);
 }
 
 
 void Assembler::idivq(Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src);
   emit(0xF7);
   emit_modrm(0x7, src);
@@ -1126,7 +1097,6 @@ void Assembler::idivq(Register src) {
 
 void Assembler::idivl(Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(src);
   emit(0xF7);
   emit_modrm(0x7, src);
@@ -1135,7 +1105,6 @@ void Assembler::idivl(Register src) {
 
 void Assembler::imul(Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src);
   emit(0xF7);
   emit_modrm(0x5, src);
@@ -1144,7 +1113,6 @@ void Assembler::imul(Register src) {
 
 void Assembler::imul(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x0F);
   emit(0xAF);
@@ -1154,7 +1122,6 @@ void Assembler::imul(Register dst, Register src) {
 
 void Assembler::imul(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x0F);
   emit(0xAF);
@@ -1164,7 +1131,6 @@ void Assembler::imul(Register dst, const Operand& src) {
 
 void Assembler::imul(Register dst, Register src, Immediate imm) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   if (is_int8(imm.value_)) {
     emit(0x6B);
@@ -1180,7 +1146,6 @@ void Assembler::imul(Register dst, Register src, Immediate imm) {
 
 void Assembler::imull(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xAF);
@@ -1190,7 +1155,6 @@ void Assembler::imull(Register dst, Register src) {
 
 void Assembler::imull(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xAF);
@@ -1200,7 +1164,6 @@ void Assembler::imull(Register dst, const Operand& src) {
 
 void Assembler::imull(Register dst, Register src, Immediate imm) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   if (is_int8(imm.value_)) {
     emit(0x6B);
@@ -1216,7 +1179,6 @@ void Assembler::imull(Register dst, Register src, Immediate imm) {
 
 void Assembler::incq(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xFF);
   emit_modrm(0x0, dst);
@@ -1225,7 +1187,6 @@ void Assembler::incq(Register dst) {
 
 void Assembler::incq(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xFF);
   emit_operand(0, dst);
@@ -1234,7 +1195,6 @@ void Assembler::incq(const Operand& dst) {
 
 void Assembler::incl(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xFF);
   emit_operand(0, dst);
@@ -1243,7 +1203,6 @@ void Assembler::incl(const Operand& dst) {
 
 void Assembler::incl(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xFF);
   emit_modrm(0, dst);
@@ -1252,12 +1211,11 @@ void Assembler::incl(Register dst) {
 
 void Assembler::int3() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xCC);
 }
 
 
-void Assembler::j(Condition cc, Label* L) {
+void Assembler::j(Condition cc, Label* L, Label::Distance distance) {
   if (cc == always) {
     jmp(L);
     return;
@@ -1265,7 +1223,6 @@ void Assembler::j(Condition cc, Label* L) {
     return;
   }
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint4(cc));
   if (L->is_bound()) {
     const int short_size = 2;
@@ -1282,6 +1239,17 @@ void Assembler::j(Condition cc, Label* L) {
       emit(0x80 | cc);
       emitl(offs - long_size);
     }
+  } else if (distance == Label::kNear) {
+    // 0111 tttn #8-bit disp
+    emit(0x70 | cc);
+    byte disp = 0x00;
+    if (L->is_near_linked()) {
+      int offset = L->near_link_pos() - pc_offset();
+      ASSERT(is_int8(offset));
+      disp = static_cast<byte>(offset & 0xFF);
+    }
+    L->link_to(pc_offset(), Label::kNear);
+    emit(disp);
   } else if (L->is_linked()) {
     // 0000 1111 1000 tttn #32-bit disp.
     emit(0x0F);
@@ -1303,7 +1271,6 @@ void Assembler::j(Condition cc,
                   Handle<Code> target,
                   RelocInfo::Mode rmode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint4(cc));
   // 0000 1111 1000 tttn #32-bit disp.
   emit(0x0F);
@@ -1312,30 +1279,8 @@ void Assembler::j(Condition cc,
 }
 
 
-void Assembler::j(Condition cc, NearLabel* L, Hint hint) {
+void Assembler::jmp(Label* L, Label::Distance distance) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
-  ASSERT(0 <= cc && cc < 16);
-  if (FLAG_emit_branch_hints && hint != no_hint) emit(hint);
-  if (L->is_bound()) {
-    const int short_size = 2;
-    int offs = L->pos() - pc_offset();
-    ASSERT(offs <= 0);
-    ASSERT(is_int8(offs - short_size));
-    // 0111 tttn #8-bit disp
-    emit(0x70 | cc);
-    emit((offs - short_size) & 0xFF);
-  } else {
-    emit(0x70 | cc);
-    emit(0x00);      // The displacement will be resolved later.
-    L->link_to(pc_offset());
-  }
-}
-
-
-void Assembler::jmp(Label* L) {
-  EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   const int short_size = sizeof(int8_t);
   const int long_size = sizeof(int32_t);
   if (L->is_bound()) {
@@ -1350,7 +1295,17 @@ void Assembler::jmp(Label* L) {
       emit(0xE9);
       emitl(offs - long_size);
     }
-  } else  if (L->is_linked()) {
+  } else if (distance == Label::kNear) {
+    emit(0xEB);
+    byte disp = 0x00;
+    if (L->is_near_linked()) {
+      int offset = L->near_link_pos() - pc_offset();
+      ASSERT(is_int8(offset));
+      disp = static_cast<byte>(offset & 0xFF);
+    }
+    L->link_to(pc_offset(), Label::kNear);
+    emit(disp);
+  } else if (L->is_linked()) {
     // 1110 1001 #32-bit disp.
     emit(0xE9);
     emitl(L->pos());
@@ -1368,35 +1323,14 @@ void Assembler::jmp(Label* L) {
 
 void Assembler::jmp(Handle<Code> target, RelocInfo::Mode rmode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // 1110 1001 #32-bit disp.
   emit(0xE9);
   emit_code_target(target, rmode);
 }
 
 
-void Assembler::jmp(NearLabel* L) {
-  EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
-  if (L->is_bound()) {
-    const int short_size = 2;
-    int offs = L->pos() - pc_offset();
-    ASSERT(offs <= 0);
-    ASSERT(is_int8(offs - short_size));
-    // 1110 1011 #8-bit disp.
-    emit(0xEB);
-    emit((offs - short_size) & 0xFF);
-  } else {
-    emit(0xEB);
-    emit(0x00);      // The displacement will be resolved later.
-    L->link_to(pc_offset());
-  }
-}
-
-
 void Assembler::jmp(Register target) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode FF/4 r64.
   emit_optional_rex_32(target);
   emit(0xFF);
@@ -1406,7 +1340,6 @@ void Assembler::jmp(Register target) {
 
 void Assembler::jmp(const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   // Opcode FF/4 m64.
   emit_optional_rex_32(src);
   emit(0xFF);
@@ -1416,7 +1349,6 @@ void Assembler::jmp(const Operand& src) {
 
 void Assembler::lea(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x8D);
   emit_operand(dst, src);
@@ -1425,7 +1357,6 @@ void Assembler::lea(Register dst, const Operand& src) {
 
 void Assembler::leal(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x8D);
   emit_operand(dst, src);
@@ -1434,7 +1365,6 @@ void Assembler::leal(Register dst, const Operand& src) {
 
 void Assembler::load_rax(void* value, RelocInfo::Mode mode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x48);  // REX.W
   emit(0xA1);
   emitq(reinterpret_cast<uintptr_t>(value), mode);
@@ -1448,15 +1378,18 @@ void Assembler::load_rax(ExternalReference ref) {
 
 void Assembler::leave() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xC9);
 }
 
 
 void Assembler::movb(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
-  emit_rex_32(dst, src);
+  if (dst.code() > 3) {
+    // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
+    emit_rex_32(dst, src);
+  } else {
+    emit_optional_rex_32(dst, src);
+  }
   emit(0x8A);
   emit_operand(dst, src);
 }
@@ -1464,18 +1397,21 @@ void Assembler::movb(Register dst, const Operand& src) {
 
 void Assembler::movb(Register dst, Immediate imm) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
-  emit_rex_32(dst);
-  emit(0xC6);
-  emit_modrm(0x0, dst);
+  if (dst.code() > 3) {
+    emit_rex_32(dst);
+  }
+  emit(0xB0 + dst.low_bits());
   emit(imm.value_);
 }
 
 
 void Assembler::movb(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
-  emit_rex_32(src, dst);
+  if (src.code() > 3) {
+    emit_rex_32(src, dst);
+  } else {
+    emit_optional_rex_32(src, dst);
+  }
   emit(0x88);
   emit_operand(src, dst);
 }
@@ -1483,7 +1419,6 @@ void Assembler::movb(const Operand& dst, Register src) {
 
 void Assembler::movw(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(src, dst);
   emit(0x89);
@@ -1493,7 +1428,6 @@ void Assembler::movw(const Operand& dst, Register src) {
 
 void Assembler::movl(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x8B);
   emit_operand(dst, src);
@@ -1502,7 +1436,6 @@ void Assembler::movl(Register dst, const Operand& src) {
 
 void Assembler::movl(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.low_bits() == 4) {
     emit_optional_rex_32(src, dst);
     emit(0x89);
@@ -1517,7 +1450,6 @@ void Assembler::movl(Register dst, Register src) {
 
 void Assembler::movl(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(src, dst);
   emit(0x89);
   emit_operand(src, dst);
@@ -1526,27 +1458,23 @@ void Assembler::movl(const Operand& dst, Register src) {
 
 void Assembler::movl(const Operand& dst, Immediate value) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xC7);
   emit_operand(0x0, dst);
-  emit(value);  // Only 32-bit immediates are possible, not 8-bit immediates.
+  emit(value);
 }
 
 
 void Assembler::movl(Register dst, Immediate value) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
-  emit(0xC7);
-  emit_modrm(0x0, dst);
-  emit(value);  // Only 32-bit immediates are possible, not 8-bit immediates.
+  emit(0xB8 + dst.low_bits());
+  emit(value);
 }
 
 
 void Assembler::movq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x8B);
   emit_operand(dst, src);
@@ -1555,7 +1483,6 @@ void Assembler::movq(Register dst, const Operand& src) {
 
 void Assembler::movq(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.low_bits() == 4) {
     emit_rex_64(src, dst);
     emit(0x89);
@@ -1570,7 +1497,6 @@ void Assembler::movq(Register dst, Register src) {
 
 void Assembler::movq(Register dst, Immediate value) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xC7);
   emit_modrm(0x0, dst);
@@ -1580,7 +1506,6 @@ void Assembler::movq(Register dst, Immediate value) {
 
 void Assembler::movq(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src, dst);
   emit(0x89);
   emit_operand(src, dst);
@@ -1592,7 +1517,6 @@ void Assembler::movq(Register dst, void* value, RelocInfo::Mode rmode) {
   // address is not GC safe. Use the handle version instead.
   ASSERT(rmode > RelocInfo::LAST_GCED_ENUM);
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xB8 | dst.low_bits());
   emitq(reinterpret_cast<uintptr_t>(value), rmode);
@@ -1614,7 +1538,6 @@ void Assembler::movq(Register dst, int64_t value, RelocInfo::Mode rmode) {
     // value.
   }
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xB8 | dst.low_bits());
   emitq(value, rmode);
@@ -1629,7 +1552,6 @@ void Assembler::movq(Register dst, ExternalReference ref) {
 
 void Assembler::movq(const Operand& dst, Immediate value) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xC7);
   emit_operand(0, dst);
@@ -1641,7 +1563,6 @@ void Assembler::movq(const Operand& dst, Immediate value) {
 // (as a 32-bit offset sign extended to 64-bit).
 void Assembler::movl(const Operand& dst, Label* src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xC7);
   emit_operand(0, dst);
@@ -1671,9 +1592,8 @@ void Assembler::movq(Register dst, Handle<Object> value, RelocInfo::Mode mode) {
     movq(dst, reinterpret_cast<int64_t>(*value), RelocInfo::NONE);
   } else {
     EnsureSpace ensure_space(this);
-    last_pc_ = pc_;
     ASSERT(value->IsHeapObject());
-    ASSERT(!Heap::InNewSpace(*value));
+    ASSERT(!HEAP->InNewSpace(*value));
     emit_rex_64(dst);
     emit(0xB8 | dst.low_bits());
     emitq(reinterpret_cast<uintptr_t>(value.location()), mode);
@@ -1683,7 +1603,6 @@ void Assembler::movq(Register dst, Handle<Object> value, RelocInfo::Mode mode) {
 
 void Assembler::movsxbq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x0F);
   emit(0xBE);
@@ -1693,7 +1612,6 @@ void Assembler::movsxbq(Register dst, const Operand& src) {
 
 void Assembler::movsxwq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x0F);
   emit(0xBF);
@@ -1703,7 +1621,6 @@ void Assembler::movsxwq(Register dst, const Operand& src) {
 
 void Assembler::movsxlq(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x63);
   emit_modrm(dst, src);
@@ -1712,7 +1629,6 @@ void Assembler::movsxlq(Register dst, Register src) {
 
 void Assembler::movsxlq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst, src);
   emit(0x63);
   emit_operand(dst, src);
@@ -1721,7 +1637,6 @@ void Assembler::movsxlq(Register dst, const Operand& src) {
 
 void Assembler::movzxbq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xB6);
@@ -1731,7 +1646,6 @@ void Assembler::movzxbq(Register dst, const Operand& src) {
 
 void Assembler::movzxbl(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xB6);
@@ -1741,7 +1655,6 @@ void Assembler::movzxbl(Register dst, const Operand& src) {
 
 void Assembler::movzxwq(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xB7);
@@ -1751,7 +1664,6 @@ void Assembler::movzxwq(Register dst, const Operand& src) {
 
 void Assembler::movzxwl(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xB7);
@@ -1761,7 +1673,6 @@ void Assembler::movzxwl(Register dst, const Operand& src) {
 
 void Assembler::repmovsb() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit(0xA4);
 }
@@ -1769,7 +1680,6 @@ void Assembler::repmovsb() {
 
 void Assembler::repmovsw() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);  // Operand size override.
   emit(0xF3);
   emit(0xA4);
@@ -1778,7 +1688,6 @@ void Assembler::repmovsw() {
 
 void Assembler::repmovsl() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit(0xA5);
 }
@@ -1786,7 +1695,6 @@ void Assembler::repmovsl() {
 
 void Assembler::repmovsq() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_rex_64();
   emit(0xA5);
@@ -1795,7 +1703,6 @@ void Assembler::repmovsq() {
 
 void Assembler::mul(Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src);
   emit(0xF7);
   emit_modrm(0x4, src);
@@ -1804,7 +1711,6 @@ void Assembler::mul(Register src) {
 
 void Assembler::neg(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xF7);
   emit_modrm(0x3, dst);
@@ -1813,7 +1719,6 @@ void Assembler::neg(Register dst) {
 
 void Assembler::negl(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xF7);
   emit_modrm(0x3, dst);
@@ -1822,7 +1727,6 @@ void Assembler::negl(Register dst) {
 
 void Assembler::neg(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xF7);
   emit_operand(3, dst);
@@ -1831,14 +1735,12 @@ void Assembler::neg(const Operand& dst) {
 
 void Assembler::nop() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x90);
 }
 
 
 void Assembler::not_(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xF7);
   emit_modrm(0x2, dst);
@@ -1847,7 +1749,6 @@ void Assembler::not_(Register dst) {
 
 void Assembler::not_(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(dst);
   emit(0xF7);
   emit_operand(2, dst);
@@ -1856,7 +1757,6 @@ void Assembler::not_(const Operand& dst) {
 
 void Assembler::notl(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0xF7);
   emit_modrm(0x2, dst);
@@ -1881,7 +1781,6 @@ void Assembler::nop(int n) {
   ASSERT(1 <= n);
   ASSERT(n <= 9);
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   switch (n) {
   case 1:
     emit(0x90);
@@ -1952,7 +1851,6 @@ void Assembler::nop(int n) {
 
 void Assembler::pop(Register dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0x58 | dst.low_bits());
 }
@@ -1960,7 +1858,6 @@ void Assembler::pop(Register dst) {
 
 void Assembler::pop(const Operand& dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(dst);
   emit(0x8F);
   emit_operand(0, dst);
@@ -1969,14 +1866,12 @@ void Assembler::pop(const Operand& dst) {
 
 void Assembler::popfq() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x9D);
 }
 
 
 void Assembler::push(Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(src);
   emit(0x50 | src.low_bits());
 }
@@ -1984,7 +1879,6 @@ void Assembler::push(Register src) {
 
 void Assembler::push(const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(src);
   emit(0xFF);
   emit_operand(6, src);
@@ -1993,7 +1887,6 @@ void Assembler::push(const Operand& src) {
 
 void Assembler::push(Immediate value) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (is_int8(value.value_)) {
     emit(0x6A);
     emit(value.value_);  // Emit low byte of value.
@@ -2006,7 +1899,6 @@ void Assembler::push(Immediate value) {
 
 void Assembler::push_imm32(int32_t imm32) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x68);
   emitl(imm32);
 }
@@ -2014,14 +1906,12 @@ void Assembler::push_imm32(int32_t imm32) {
 
 void Assembler::pushfq() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x9C);
 }
 
 
 void Assembler::rdtsc() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x0F);
   emit(0x31);
 }
@@ -2029,7 +1919,6 @@ void Assembler::rdtsc() {
 
 void Assembler::ret(int imm16) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint16(imm16));
   if (imm16 == 0) {
     emit(0xC3);
@@ -2047,7 +1936,6 @@ void Assembler::setcc(Condition cc, Register reg) {
     return;
   }
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   ASSERT(is_uint4(cc));
   if (reg.code() > 3) {  // Use x64 byte registers, where different.
     emit_rex_32(reg);
@@ -2060,7 +1948,6 @@ void Assembler::setcc(Condition cc, Register reg) {
 
 void Assembler::shld(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src, dst);
   emit(0x0F);
   emit(0xA5);
@@ -2070,7 +1957,6 @@ void Assembler::shld(Register dst, Register src) {
 
 void Assembler::shrd(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(src, dst);
   emit(0x0F);
   emit(0xAD);
@@ -2080,7 +1966,6 @@ void Assembler::shrd(Register dst, Register src) {
 
 void Assembler::xchg(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.is(rax) || dst.is(rax)) {  // Single-byte encoding
     Register other = src.is(rax) ? dst : src;
     emit_rex_64(other);
@@ -2099,7 +1984,6 @@ void Assembler::xchg(Register dst, Register src) {
 
 void Assembler::store_rax(void* dst, RelocInfo::Mode mode) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x48);  // REX.W
   emit(0xA3);
   emitq(reinterpret_cast<uintptr_t>(dst), mode);
@@ -2113,7 +1997,6 @@ void Assembler::store_rax(ExternalReference ref) {
 
 void Assembler::testb(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.low_bits() == 4) {
     emit_rex_32(src, dst);
     emit(0x84);
@@ -2132,7 +2015,6 @@ void Assembler::testb(Register dst, Register src) {
 void Assembler::testb(Register reg, Immediate mask) {
   ASSERT(is_int8(mask.value_) || is_uint8(mask.value_));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (reg.is(rax)) {
     emit(0xA8);
     emit(mask.value_);  // Low byte emitted.
@@ -2151,7 +2033,6 @@ void Assembler::testb(Register reg, Immediate mask) {
 void Assembler::testb(const Operand& op, Immediate mask) {
   ASSERT(is_int8(mask.value_) || is_uint8(mask.value_));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(rax, op);
   emit(0xF6);
   emit_operand(rax, op);  // Operation code 0
@@ -2161,7 +2042,6 @@ void Assembler::testb(const Operand& op, Immediate mask) {
 
 void Assembler::testb(const Operand& op, Register reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (reg.code() > 3) {
     // Register is not one of al, bl, cl, dl.  Its encoding needs REX.
     emit_rex_32(reg, op);
@@ -2175,7 +2055,6 @@ void Assembler::testb(const Operand& op, Register reg) {
 
 void Assembler::testl(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.low_bits() == 4) {
     emit_optional_rex_32(src, dst);
     emit(0x85);
@@ -2195,7 +2074,6 @@ void Assembler::testl(Register reg, Immediate mask) {
     return;
   }
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (reg.is(rax)) {
     emit(0xA9);
     emit(mask);
@@ -2215,7 +2093,6 @@ void Assembler::testl(const Operand& op, Immediate mask) {
     return;
   }
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(rax, op);
   emit(0xF7);
   emit_operand(rax, op);  // Operation code 0
@@ -2225,7 +2102,6 @@ void Assembler::testl(const Operand& op, Immediate mask) {
 
 void Assembler::testq(const Operand& op, Register reg) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_rex_64(reg, op);
   emit(0x85);
   emit_operand(reg, op);
@@ -2234,7 +2110,6 @@ void Assembler::testq(const Operand& op, Register reg) {
 
 void Assembler::testq(Register dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (src.low_bits() == 4) {
     emit_rex_64(src, dst);
     emit(0x85);
@@ -2249,7 +2124,6 @@ void Assembler::testq(Register dst, Register src) {
 
 void Assembler::testq(Register dst, Immediate mask) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   if (dst.is(rax)) {
     emit_rex_64();
     emit(0xA9);
@@ -2268,14 +2142,12 @@ void Assembler::testq(Register dst, Immediate mask) {
 
 void Assembler::fld(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xD9, 0xC0, i);
 }
 
 
 void Assembler::fld1() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xE8);
 }
@@ -2283,7 +2155,6 @@ void Assembler::fld1() {
 
 void Assembler::fldz() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xEE);
 }
@@ -2291,7 +2162,6 @@ void Assembler::fldz() {
 
 void Assembler::fldpi() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xEB);
 }
@@ -2299,7 +2169,6 @@ void Assembler::fldpi() {
 
 void Assembler::fldln2() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xED);
 }
@@ -2307,7 +2176,6 @@ void Assembler::fldln2() {
 
 void Assembler::fld_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xD9);
   emit_operand(0, adr);
@@ -2316,7 +2184,6 @@ void Assembler::fld_s(const Operand& adr) {
 
 void Assembler::fld_d(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDD);
   emit_operand(0, adr);
@@ -2325,7 +2192,6 @@ void Assembler::fld_d(const Operand& adr) {
 
 void Assembler::fstp_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xD9);
   emit_operand(3, adr);
@@ -2334,7 +2200,6 @@ void Assembler::fstp_s(const Operand& adr) {
 
 void Assembler::fstp_d(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDD);
   emit_operand(3, adr);
@@ -2344,14 +2209,12 @@ void Assembler::fstp_d(const Operand& adr) {
 void Assembler::fstp(int index) {
   ASSERT(is_uint3(index));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDD, 0xD8, index);
 }
 
 
 void Assembler::fild_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(0, adr);
@@ -2360,7 +2223,6 @@ void Assembler::fild_s(const Operand& adr) {
 
 void Assembler::fild_d(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDF);
   emit_operand(5, adr);
@@ -2369,7 +2231,6 @@ void Assembler::fild_d(const Operand& adr) {
 
 void Assembler::fistp_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(3, adr);
@@ -2379,7 +2240,6 @@ void Assembler::fistp_s(const Operand& adr) {
 void Assembler::fisttp_s(const Operand& adr) {
   ASSERT(CpuFeatures::IsEnabled(SSE3));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(1, adr);
@@ -2389,7 +2249,6 @@ void Assembler::fisttp_s(const Operand& adr) {
 void Assembler::fisttp_d(const Operand& adr) {
   ASSERT(CpuFeatures::IsEnabled(SSE3));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDD);
   emit_operand(1, adr);
@@ -2398,7 +2257,6 @@ void Assembler::fisttp_d(const Operand& adr) {
 
 void Assembler::fist_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDB);
   emit_operand(2, adr);
@@ -2407,7 +2265,6 @@ void Assembler::fist_s(const Operand& adr) {
 
 void Assembler::fistp_d(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDF);
   emit_operand(7, adr);
@@ -2416,7 +2273,6 @@ void Assembler::fistp_d(const Operand& adr) {
 
 void Assembler::fabs() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xE1);
 }
@@ -2424,7 +2280,6 @@ void Assembler::fabs() {
 
 void Assembler::fchs() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xE0);
 }
@@ -2432,7 +2287,6 @@ void Assembler::fchs() {
 
 void Assembler::fcos() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xFF);
 }
@@ -2440,7 +2294,6 @@ void Assembler::fcos() {
 
 void Assembler::fsin() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xFE);
 }
@@ -2448,7 +2301,6 @@ void Assembler::fsin() {
 
 void Assembler::fyl2x() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xF1);
 }
@@ -2456,21 +2308,18 @@ void Assembler::fyl2x() {
 
 void Assembler::fadd(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDC, 0xC0, i);
 }
 
 
 void Assembler::fsub(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDC, 0xE8, i);
 }
 
 
 void Assembler::fisub_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_optional_rex_32(adr);
   emit(0xDA);
   emit_operand(4, adr);
@@ -2479,56 +2328,48 @@ void Assembler::fisub_s(const Operand& adr) {
 
 void Assembler::fmul(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDC, 0xC8, i);
 }
 
 
 void Assembler::fdiv(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDC, 0xF8, i);
 }
 
 
 void Assembler::faddp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDE, 0xC0, i);
 }
 
 
 void Assembler::fsubp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDE, 0xE8, i);
 }
 
 
 void Assembler::fsubrp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDE, 0xE0, i);
 }
 
 
 void Assembler::fmulp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDE, 0xC8, i);
 }
 
 
 void Assembler::fdivp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDE, 0xF8, i);
 }
 
 
 void Assembler::fprem() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xF8);
 }
@@ -2536,7 +2377,6 @@ void Assembler::fprem() {
 
 void Assembler::fprem1() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xF5);
 }
@@ -2544,14 +2384,12 @@ void Assembler::fprem1() {
 
 void Assembler::fxch(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xD9, 0xC8, i);
 }
 
 
 void Assembler::fincstp() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xF7);
 }
@@ -2559,14 +2397,12 @@ void Assembler::fincstp() {
 
 void Assembler::ffree(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDD, 0xC0, i);
 }
 
 
 void Assembler::ftst() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xE4);
 }
@@ -2574,14 +2410,12 @@ void Assembler::ftst() {
 
 void Assembler::fucomp(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit_farith(0xDD, 0xE8, i);
 }
 
 
 void Assembler::fucompp() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDA);
   emit(0xE9);
 }
@@ -2589,7 +2423,6 @@ void Assembler::fucompp() {
 
 void Assembler::fucomi(int i) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDB);
   emit(0xE8 + i);
 }
@@ -2597,7 +2430,6 @@ void Assembler::fucomi(int i) {
 
 void Assembler::fucomip() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDF);
   emit(0xE9);
 }
@@ -2605,7 +2437,6 @@ void Assembler::fucomip() {
 
 void Assembler::fcompp() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDE);
   emit(0xD9);
 }
@@ -2613,7 +2444,6 @@ void Assembler::fcompp() {
 
 void Assembler::fnstsw_ax() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDF);
   emit(0xE0);
 }
@@ -2621,14 +2451,12 @@ void Assembler::fnstsw_ax() {
 
 void Assembler::fwait() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x9B);
 }
 
 
 void Assembler::frndint() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xD9);
   emit(0xFC);
 }
@@ -2636,7 +2464,6 @@ void Assembler::frndint() {
 
 void Assembler::fnclex() {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xDB);
   emit(0xE2);
 }
@@ -2646,7 +2473,6 @@ void Assembler::sahf() {
   // TODO(X64): Test for presence. Not all 64-bit intel CPU's have sahf
   // in 64-bit mode. Test CpuID.
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x9E);
 }
 
@@ -2662,7 +2488,6 @@ void Assembler::emit_farith(int b1, int b2, int i) {
 
 void Assembler::movd(XMMRegister dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2673,7 +2498,6 @@ void Assembler::movd(XMMRegister dst, Register src) {
 
 void Assembler::movd(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(src, dst);
   emit(0x0F);
@@ -2684,7 +2508,6 @@ void Assembler::movd(Register dst, XMMRegister src) {
 
 void Assembler::movq(XMMRegister dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_rex_64(dst, src);
   emit(0x0F);
@@ -2695,7 +2518,6 @@ void Assembler::movq(XMMRegister dst, Register src) {
 
 void Assembler::movq(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_rex_64(src, dst);
   emit(0x0F);
@@ -2704,10 +2526,26 @@ void Assembler::movq(Register dst, XMMRegister src) {
 }
 
 
+void Assembler::movq(XMMRegister dst, XMMRegister src) {
+  EnsureSpace ensure_space(this);
+  if (dst.low_bits() == 4) {
+    // Avoid unnecessary SIB byte.
+    emit(0xf3);
+    emit_optional_rex_32(dst, src);
+    emit(0x0F);
+    emit(0x7e);
+    emit_sse_operand(dst, src);
+  } else {
+    emit(0x66);
+    emit_optional_rex_32(src, dst);
+    emit(0x0F);
+    emit(0xD6);
+    emit_sse_operand(src, dst);
+  }
+}
+
 void Assembler::movdqa(const Operand& dst, XMMRegister src) {
-  ASSERT(CpuFeatures::IsEnabled(SSE2));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_rex_64(src, dst);
   emit(0x0F);
@@ -2717,9 +2555,7 @@ void Assembler::movdqa(const Operand& dst, XMMRegister src) {
 
 
 void Assembler::movdqa(XMMRegister dst, const Operand& src) {
-  ASSERT(CpuFeatures::IsEnabled(SSE2));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_rex_64(dst, src);
   emit(0x0F);
@@ -2731,7 +2567,6 @@ void Assembler::movdqa(XMMRegister dst, const Operand& src) {
 void Assembler::extractps(Register dst, XMMRegister src, byte imm8) {
   ASSERT(is_uint2(imm8));
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2744,7 +2579,6 @@ void Assembler::extractps(Register dst, XMMRegister src, byte imm8) {
 
 void Assembler::movsd(const Operand& dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);  // double
   emit_optional_rex_32(src, dst);
   emit(0x0F);
@@ -2755,7 +2589,6 @@ void Assembler::movsd(const Operand& dst, XMMRegister src) {
 
 void Assembler::movsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);  // double
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2766,7 +2599,6 @@ void Assembler::movsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::movsd(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);  // double
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2775,9 +2607,44 @@ void Assembler::movsd(XMMRegister dst, const Operand& src) {
 }
 
 
+void Assembler::movaps(XMMRegister dst, XMMRegister src) {
+  EnsureSpace ensure_space(this);
+  if (src.low_bits() == 4) {
+    // Try to avoid an unnecessary SIB byte.
+    emit_optional_rex_32(src, dst);
+    emit(0x0F);
+    emit(0x29);
+    emit_sse_operand(src, dst);
+  } else {
+    emit_optional_rex_32(dst, src);
+    emit(0x0F);
+    emit(0x28);
+    emit_sse_operand(dst, src);
+  }
+}
+
+
+void Assembler::movapd(XMMRegister dst, XMMRegister src) {
+  EnsureSpace ensure_space(this);
+  if (src.low_bits() == 4) {
+    // Try to avoid an unnecessary SIB byte.
+    emit(0x66);
+    emit_optional_rex_32(src, dst);
+    emit(0x0F);
+    emit(0x29);
+    emit_sse_operand(src, dst);
+  } else {
+    emit(0x66);
+    emit_optional_rex_32(dst, src);
+    emit(0x0F);
+    emit(0x28);
+    emit_sse_operand(dst, src);
+  }
+}
+
+
 void Assembler::movss(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);  // single
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2788,7 +2655,6 @@ void Assembler::movss(XMMRegister dst, const Operand& src) {
 
 void Assembler::movss(const Operand& src, XMMRegister dst) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);  // single
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2799,7 +2665,6 @@ void Assembler::movss(const Operand& src, XMMRegister dst) {
 
 void Assembler::cvttss2si(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2810,7 +2675,6 @@ void Assembler::cvttss2si(Register dst, const Operand& src) {
 
 void Assembler::cvttss2si(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2821,7 +2685,6 @@ void Assembler::cvttss2si(Register dst, XMMRegister src) {
 
 void Assembler::cvttsd2si(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2832,7 +2695,6 @@ void Assembler::cvttsd2si(Register dst, const Operand& src) {
 
 void Assembler::cvttsd2si(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2843,7 +2705,6 @@ void Assembler::cvttsd2si(Register dst, XMMRegister src) {
 
 void Assembler::cvttsd2siq(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_rex_64(dst, src);
   emit(0x0F);
@@ -2854,7 +2715,6 @@ void Assembler::cvttsd2siq(Register dst, XMMRegister src) {
 
 void Assembler::cvtlsi2sd(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2865,7 +2725,6 @@ void Assembler::cvtlsi2sd(XMMRegister dst, const Operand& src) {
 
 void Assembler::cvtlsi2sd(XMMRegister dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2876,7 +2735,6 @@ void Assembler::cvtlsi2sd(XMMRegister dst, Register src) {
 
 void Assembler::cvtlsi2ss(XMMRegister dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2887,7 +2745,6 @@ void Assembler::cvtlsi2ss(XMMRegister dst, Register src) {
 
 void Assembler::cvtqsi2sd(XMMRegister dst, Register src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_rex_64(dst, src);
   emit(0x0F);
@@ -2898,7 +2755,6 @@ void Assembler::cvtqsi2sd(XMMRegister dst, Register src) {
 
 void Assembler::cvtss2sd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2909,7 +2765,6 @@ void Assembler::cvtss2sd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::cvtss2sd(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF3);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2920,7 +2775,6 @@ void Assembler::cvtss2sd(XMMRegister dst, const Operand& src) {
 
 void Assembler::cvtsd2ss(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2931,7 +2785,6 @@ void Assembler::cvtsd2ss(XMMRegister dst, XMMRegister src) {
 
 void Assembler::cvtsd2si(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2942,7 +2795,6 @@ void Assembler::cvtsd2si(Register dst, XMMRegister src) {
 
 void Assembler::cvtsd2siq(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_rex_64(dst, src);
   emit(0x0F);
@@ -2953,7 +2805,6 @@ void Assembler::cvtsd2siq(Register dst, XMMRegister src) {
 
 void Assembler::addsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2964,7 +2815,6 @@ void Assembler::addsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::mulsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2975,7 +2825,6 @@ void Assembler::mulsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::subsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2986,7 +2835,6 @@ void Assembler::subsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::divsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -2997,7 +2845,6 @@ void Assembler::divsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::andpd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -3008,7 +2855,6 @@ void Assembler::andpd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::orpd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -3019,7 +2865,6 @@ void Assembler::orpd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::xorpd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -3028,9 +2873,17 @@ void Assembler::xorpd(XMMRegister dst, XMMRegister src) {
 }
 
 
+void Assembler::xorps(XMMRegister dst, XMMRegister src) {
+  EnsureSpace ensure_space(this);
+  emit_optional_rex_32(dst, src);
+  emit(0x0F);
+  emit(0x57);
+  emit_sse_operand(dst, src);
+}
+
+
 void Assembler::sqrtsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0xF2);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
@@ -3041,7 +2894,6 @@ void Assembler::sqrtsd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::ucomisd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0f);
@@ -3052,7 +2904,6 @@ void Assembler::ucomisd(XMMRegister dst, XMMRegister src) {
 
 void Assembler::ucomisd(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0f);
@@ -3061,9 +2912,23 @@ void Assembler::ucomisd(XMMRegister dst, const Operand& src) {
 }
 
 
+void Assembler::roundsd(XMMRegister dst, XMMRegister src,
+                        Assembler::RoundingMode mode) {
+  ASSERT(CpuFeatures::IsEnabled(SSE4_1));
+  EnsureSpace ensure_space(this);
+  emit(0x66);
+  emit_optional_rex_32(dst, src);
+  emit(0x0f);
+  emit(0x3a);
+  emit(0x0b);
+  emit_sse_operand(dst, src);
+  // Mask precision exeption.
+  emit(static_cast<byte>(mode) | 0x8);
+}
+
+
 void Assembler::movmskpd(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
-  last_pc_ = pc_;
   emit(0x66);
   emit_optional_rex_32(dst, src);
   emit(0x0f);
@@ -3114,7 +2979,7 @@ void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
       Serializer::TooLateToEnableNow();
     }
 #endif
-    if (!Serializer::enabled() && !FLAG_debug_code) {
+    if (!Serializer::enabled() && !emit_debug_code()) {
       return;
     }
   }