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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/builtins/builtins-lazy-gen.h"
#include "src/builtins/builtins-utils-gen.h"
#include "src/builtins/builtins.h"
#include "src/common/globals.h"
#include "src/objects/code-inl.h"
#include "src/objects/feedback-vector.h"
#include "src/objects/shared-function-info.h"
namespace v8 {
namespace internal {
void LazyBuiltinsAssembler::GenerateTailCallToJSCode(
TNode<Code> code, TNode<JSFunction> function) {
auto argc = UncheckedParameter<Int32T>(Descriptor::kActualArgumentsCount);
auto context = Parameter<Context>(Descriptor::kContext);
auto new_target = Parameter<Object>(Descriptor::kNewTarget);
TailCallJSCode(code, context, function, new_target, argc);
}
void LazyBuiltinsAssembler::GenerateTailCallToReturnedCode(
Runtime::FunctionId function_id, TNode<JSFunction> function) {
auto context = Parameter<Context>(Descriptor::kContext);
TNode<Code> code = CAST(CallRuntime(function_id, context, function));
GenerateTailCallToJSCode(code, function);
}
void LazyBuiltinsAssembler::MaybeTailCallOptimizedCodeSlot(
TNode<JSFunction> function, TNode<FeedbackVector> feedback_vector) {
Label fallthrough(this), may_have_optimized_code(this),
maybe_needs_logging(this);
TNode<Uint16T> flags =
LoadObjectField<Uint16T>(feedback_vector, FeedbackVector::kFlagsOffset);
// Fall through if no optimization trigger or optimized code.
GotoIfNot(
IsSetWord32(flags, FeedbackVector::kFlagsHasAnyOptimizedCode |
FeedbackVector::kFlagsTieringStateIsAnyRequested |
FeedbackVector::kFlagsLogNextExecution),
&fallthrough);
GotoIfNot(
IsSetWord32(flags, FeedbackVector::kFlagsTieringStateIsAnyRequested),
&maybe_needs_logging);
GenerateTailCallToReturnedCode(Runtime::kCompileOptimized, function);
BIND(&maybe_needs_logging);
{
GotoIfNot(IsSetWord32(flags, FeedbackVector::kFlagsLogNextExecution),
&may_have_optimized_code);
GenerateTailCallToReturnedCode(Runtime::kFunctionLogNextExecution,
function);
}
BIND(&may_have_optimized_code);
{
Label heal_optimized_code_slot(this);
TNode<MaybeObject> maybe_optimized_code_entry = LoadMaybeWeakObjectField(
feedback_vector, FeedbackVector::kMaybeOptimizedCodeOffset);
// Optimized code slot is a weak reference to Code object.
TNode<Code> optimized_code = CAST(GetHeapObjectAssumeWeak(
maybe_optimized_code_entry, &heal_optimized_code_slot));
// Check if the optimized code is marked for deopt. If it is, call the
// runtime to clear it.
GotoIf(IsMarkedForDeoptimization(optimized_code),
&heal_optimized_code_slot);
// Optimized code is good, get it into the closure and link the closure into
// the optimized functions list, then tail call the optimized code.
StoreObjectField(function, JSFunction::kCodeOffset, optimized_code);
Comment("MaybeTailCallOptimizedCodeSlot:: GenerateTailCallToJSCode");
GenerateTailCallToJSCode(optimized_code, function);
// Optimized code slot contains deoptimized code, or the code is cleared
// and tiering state hasn't yet been updated. Evict the code, update the
// state and re-enter the closure's code.
BIND(&heal_optimized_code_slot);
GenerateTailCallToReturnedCode(Runtime::kHealOptimizedCodeSlot, function);
}
// Fall-through if the optimized code cell is clear and the tiering state is
// kNone.
BIND(&fallthrough);
}
void LazyBuiltinsAssembler::CompileLazy(TNode<JSFunction> function) {
// First lookup code, maybe we don't need to compile!
Label compile_function(this, Label::kDeferred);
// Check the code object for the SFI. If SFI's code entry points to
// CompileLazy, then we need to lazy compile regardless of the function or
// tiering state.
TNode<SharedFunctionInfo> shared =
CAST(LoadObjectField(function, JSFunction::kSharedFunctionInfoOffset));
TVARIABLE(Uint16T, sfi_data_type);
TNode<Code> sfi_code =
GetSharedFunctionInfoCode(shared, &sfi_data_type, &compile_function);
TNode<HeapObject> feedback_cell_value = LoadFeedbackCellValue(function);
// If feedback cell isn't initialized, compile function
GotoIf(IsUndefined(feedback_cell_value), &compile_function);
CSA_DCHECK(this, TaggedNotEqual(sfi_code, HeapConstant(BUILTIN_CODE(
isolate(), CompileLazy))));
StoreObjectField(function, JSFunction::kCodeOffset, sfi_code);
Label maybe_use_sfi_code(this);
// If there is no feedback, don't check for optimized code.
GotoIf(HasInstanceType(feedback_cell_value, CLOSURE_FEEDBACK_CELL_ARRAY_TYPE),
&maybe_use_sfi_code);
// If it isn't undefined or fixed array it must be a feedback vector.
CSA_DCHECK(this, IsFeedbackVector(feedback_cell_value));
// Is there a tiering state or optimized code in the feedback vector?
MaybeTailCallOptimizedCodeSlot(function, CAST(feedback_cell_value));
Goto(&maybe_use_sfi_code);
// At this point we have a candidate InstructionStream object. It's *not* a
// cached optimized InstructionStream object (we'd have tail-called it above).
// A usual case would be the InterpreterEntryTrampoline to start executing
// existing bytecode.
BIND(&maybe_use_sfi_code);
Label tailcall_code(this), baseline(this);
TVARIABLE(Code, code);
// Check if we have baseline code.
GotoIf(InstanceTypeEqual(sfi_data_type.value(), CODE_TYPE), &baseline);
code = sfi_code;
Goto(&tailcall_code);
BIND(&baseline);
// Ensure we have a feedback vector.
code = Select<Code>(
IsFeedbackVector(feedback_cell_value), [=]() { return sfi_code; },
[=]() {
return CAST(CallRuntime(Runtime::kInstallBaselineCode,
Parameter<Context>(Descriptor::kContext),
function));
});
Goto(&tailcall_code);
BIND(&tailcall_code);
GenerateTailCallToJSCode(code.value(), function);
BIND(&compile_function);
GenerateTailCallToReturnedCode(Runtime::kCompileLazy, function);
}
TF_BUILTIN(CompileLazy, LazyBuiltinsAssembler) {
auto function = Parameter<JSFunction>(Descriptor::kTarget);
CompileLazy(function);
}
TF_BUILTIN(CompileLazyDeoptimizedCode, LazyBuiltinsAssembler) {
auto function = Parameter<JSFunction>(Descriptor::kTarget);
TNode<Code> code = HeapConstant(BUILTIN_CODE(isolate(), CompileLazy));
// Set the code slot inside the JSFunction to CompileLazy.
StoreObjectField(function, JSFunction::kCodeOffset, code);
GenerateTailCallToJSCode(code, function);
}
} // namespace internal
} // namespace v8
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