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// Copyright 2015 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/fast-accessor-assembler.h"
#include "src/base/logging.h"
#include "src/code-stub-assembler.h"
#include "src/code-stubs.h" // For CallApiCallbackStub.
#include "src/handles-inl.h"
#include "src/objects.h" // For FAA::LoadInternalField impl.
namespace v8 {
namespace internal {
using compiler::Node;
using compiler::CodeAssemblerLabel;
using compiler::CodeAssemblerVariable;
FastAccessorAssembler::FastAccessorAssembler(Isolate* isolate)
: zone_(isolate->allocator(), ZONE_NAME),
isolate_(isolate),
assembler_state_(new compiler::CodeAssemblerState(
isolate, zone(), 1, Code::ComputeFlags(Code::STUB),
"FastAccessorAssembler")),
assembler_(new CodeStubAssembler(assembler_state_.get())),
state_(kBuilding) {}
FastAccessorAssembler::~FastAccessorAssembler() { Clear(); }
FastAccessorAssembler::ValueId FastAccessorAssembler::IntegerConstant(
int const_value) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->NumberConstant(const_value));
}
FastAccessorAssembler::ValueId FastAccessorAssembler::GetReceiver() {
CHECK_EQ(kBuilding, state_);
// For JS functions, the receiver is parameter 0.
return FromRaw(assembler_->Parameter(0));
}
FastAccessorAssembler::ValueId FastAccessorAssembler::LoadInternalField(
ValueId value_id, int field_no) {
CHECK_EQ(kBuilding, state_);
CodeAssemblerVariable result(assembler_.get(),
MachineRepresentation::kTagged);
LabelId is_not_jsobject = MakeLabel();
CodeAssemblerLabel merge(assembler_.get(), &result);
CheckIsJSObjectOrJump(value_id, is_not_jsobject);
Node* internal_field = assembler_->LoadObjectField(
FromId(value_id), JSObject::kHeaderSize + kPointerSize * field_no);
result.Bind(internal_field);
assembler_->Goto(&merge);
// Return null, mimicking the C++ counterpart.
SetLabel(is_not_jsobject);
result.Bind(assembler_->NullConstant());
assembler_->Goto(&merge);
// Return.
assembler_->Bind(&merge);
return FromRaw(result.value());
}
FastAccessorAssembler::ValueId
FastAccessorAssembler::LoadInternalFieldUnchecked(ValueId value_id,
int field_no) {
CHECK_EQ(kBuilding, state_);
// Defensive debug checks.
if (FLAG_debug_code) {
LabelId is_jsobject = MakeLabel();
LabelId is_not_jsobject = MakeLabel();
CheckIsJSObjectOrJump(value_id, is_not_jsobject);
assembler_->Goto(FromId(is_jsobject));
SetLabel(is_not_jsobject);
assembler_->DebugBreak();
assembler_->Goto(FromId(is_jsobject));
SetLabel(is_jsobject);
}
Node* result = assembler_->LoadObjectField(
FromId(value_id), JSObject::kHeaderSize + kPointerSize * field_no);
return FromRaw(result);
}
FastAccessorAssembler::ValueId FastAccessorAssembler::LoadValue(
ValueId value_id, int offset) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->LoadBufferObject(FromId(value_id), offset,
MachineType::IntPtr()));
}
FastAccessorAssembler::ValueId FastAccessorAssembler::LoadObject(
ValueId value_id, int offset) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->LoadBufferObject(
assembler_->LoadBufferObject(FromId(value_id), offset), 0,
MachineType::AnyTagged()));
}
FastAccessorAssembler::ValueId FastAccessorAssembler::ToSmi(ValueId value_id) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->SmiTag(FromId(value_id)));
}
void FastAccessorAssembler::ReturnValue(ValueId value_id) {
CHECK_EQ(kBuilding, state_);
assembler_->Return(FromId(value_id));
}
void FastAccessorAssembler::CheckFlagSetOrReturnNull(ValueId value_id,
int mask) {
CHECK_EQ(kBuilding, state_);
CodeAssemblerLabel pass(assembler_.get());
CodeAssemblerLabel fail(assembler_.get());
Node* value = FromId(value_id);
assembler_->Branch(
assembler_->IsSetWord(assembler_->BitcastTaggedToWord(value), mask),
&pass, &fail);
assembler_->Bind(&fail);
assembler_->Return(assembler_->NullConstant());
assembler_->Bind(&pass);
}
void FastAccessorAssembler::CheckNotZeroOrReturnNull(ValueId value_id) {
CHECK_EQ(kBuilding, state_);
CodeAssemblerLabel is_null(assembler_.get());
CodeAssemblerLabel not_null(assembler_.get());
assembler_->Branch(
assembler_->WordEqual(FromId(value_id), assembler_->SmiConstant(0)),
&is_null, &not_null);
assembler_->Bind(&is_null);
assembler_->Return(assembler_->NullConstant());
assembler_->Bind(&not_null);
}
FastAccessorAssembler::LabelId FastAccessorAssembler::MakeLabel() {
CHECK_EQ(kBuilding, state_);
return FromRaw(new CodeAssemblerLabel(assembler_.get()));
}
void FastAccessorAssembler::SetLabel(LabelId label_id) {
CHECK_EQ(kBuilding, state_);
assembler_->Bind(FromId(label_id));
}
void FastAccessorAssembler::Goto(LabelId label_id) {
CHECK_EQ(kBuilding, state_);
assembler_->Goto(FromId(label_id));
}
void FastAccessorAssembler::CheckNotZeroOrJump(ValueId value_id,
LabelId label_id) {
CHECK_EQ(kBuilding, state_);
CodeAssemblerLabel pass(assembler_.get());
assembler_->Branch(
assembler_->WordEqual(FromId(value_id), assembler_->SmiConstant(0)),
FromId(label_id), &pass);
assembler_->Bind(&pass);
}
FastAccessorAssembler::ValueId FastAccessorAssembler::Call(
FunctionCallback callback_function, ValueId arg) {
CHECK_EQ(kBuilding, state_);
// Wrap the FunctionCallback in an ExternalReference.
ApiFunction callback_api_function(FUNCTION_ADDR(callback_function));
ExternalReference callback(&callback_api_function,
ExternalReference::DIRECT_API_CALL, isolate());
// Create & call API callback via stub.
const int kJSParameterCount = 1;
CallApiCallbackStub stub(isolate(), kJSParameterCount, true, true);
CallInterfaceDescriptor descriptor = stub.GetCallInterfaceDescriptor();
DCHECK_EQ(4, descriptor.GetParameterCount());
DCHECK_EQ(0, descriptor.GetStackParameterCount());
// TODO(vogelheim): There is currently no clean way to retrieve the context
// parameter for a stub and the implementation details are hidden in
// compiler/*. The context_paramter is computed as:
// Linkage::GetJSCallContextParamIndex(descriptor->JSParameterCount())
const int kContextParameter = 3;
Node* context = assembler_->Parameter(kContextParameter);
Node* target = assembler_->HeapConstant(stub.GetCode());
Node* call = assembler_->CallStub(
descriptor, target, context,
assembler_->UndefinedConstant(), // callee (there's no JSFunction)
assembler_->UndefinedConstant(), // call_data (undefined)
assembler_->Parameter(0), // receiver (same as holder in this case)
assembler_->ExternalConstant(callback), // API callback function
FromId(arg)); // JS argument, on stack
return FromRaw(call);
}
void FastAccessorAssembler::CheckIsJSObjectOrJump(ValueId value_id,
LabelId label_id) {
CHECK_EQ(kBuilding, state_);
// Determine the 'value' object's instance type.
Node* instance_type = assembler_->LoadInstanceType(FromId(value_id));
CodeAssemblerLabel is_jsobject(assembler_.get());
// Check whether we have a proper JSObject.
assembler_->GotoIf(
assembler_->Word32Equal(
instance_type, assembler_->Int32Constant(Internals::kJSObjectType)),
&is_jsobject);
// JSApiObject?.
assembler_->GotoUnless(
assembler_->Word32Equal(instance_type, assembler_->Int32Constant(
Internals::kJSApiObjectType)),
FromId(label_id));
// Continue.
assembler_->Goto(&is_jsobject);
assembler_->Bind(&is_jsobject);
}
MaybeHandle<Code> FastAccessorAssembler::Build() {
CHECK_EQ(kBuilding, state_);
Handle<Code> code =
compiler::CodeAssembler::GenerateCode(assembler_state_.get());
state_ = !code.is_null() ? kBuilt : kError;
Clear();
return code;
}
FastAccessorAssembler::ValueId FastAccessorAssembler::FromRaw(Node* node) {
nodes_.push_back(node);
ValueId value_id = {nodes_.size() - 1};
return value_id;
}
FastAccessorAssembler::LabelId FastAccessorAssembler::FromRaw(
CodeAssemblerLabel* label) {
labels_.push_back(label);
LabelId label_id = {labels_.size() - 1};
return label_id;
}
Node* FastAccessorAssembler::FromId(ValueId value) const {
CHECK_LT(value.value_id, nodes_.size());
CHECK_NOT_NULL(nodes_.at(value.value_id));
return nodes_.at(value.value_id);
}
CodeAssemblerLabel* FastAccessorAssembler::FromId(LabelId label) const {
CHECK_LT(label.label_id, labels_.size());
CHECK_NOT_NULL(labels_.at(label.label_id));
return labels_.at(label.label_id);
}
void FastAccessorAssembler::Clear() {
for (auto label : labels_) {
delete label;
}
nodes_.clear();
labels_.clear();
}
} // namespace internal
} // namespace v8