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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.
using v8::internal::CodeStubAssembler;
using v8::internal::compiler::Node;
namespace v8 {
namespace internal {
FastAccessorAssembler::FastAccessorAssembler(Isolate* isolate)
: zone_(isolate->allocator()),
isolate_(isolate),
assembler_(new CodeStubAssembler(isolate, zone(), 1,
Code::ComputeFlags(Code::STUB),
"FastAccessorAssembler")),
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, int field_no) {
CHECK_EQ(kBuilding, state_);
CodeStubAssembler::Variable result(assembler_.get(),
MachineRepresentation::kTagged);
LabelId is_not_jsobject = MakeLabel();
CodeStubAssembler::Label merge(assembler_.get(), &result);
CheckIsJSObjectOrJump(value, is_not_jsobject);
Node* internal_field = assembler_->LoadObjectField(
FromId(value), JSObject::kHeaderSize + kPointerSize * field_no,
MachineType::Pointer());
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, 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, 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), JSObject::kHeaderSize + kPointerSize * field_no,
MachineType::Pointer());
return FromRaw(result);
}
FastAccessorAssembler::ValueId FastAccessorAssembler::LoadValue(ValueId value,
int offset) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->LoadBufferObject(FromId(value), offset,
MachineType::IntPtr()));
}
FastAccessorAssembler::ValueId FastAccessorAssembler::LoadObject(ValueId value,
int offset) {
CHECK_EQ(kBuilding, state_);
return FromRaw(assembler_->LoadBufferObject(
assembler_->LoadBufferObject(FromId(value), offset,
MachineType::Pointer()),
0, MachineType::AnyTagged()));
}
void FastAccessorAssembler::ReturnValue(ValueId value) {
CHECK_EQ(kBuilding, state_);
assembler_->Return(FromId(value));
}
void FastAccessorAssembler::CheckFlagSetOrReturnNull(ValueId value, int mask) {
CHECK_EQ(kBuilding, state_);
CodeStubAssembler::Label pass(assembler_.get());
CodeStubAssembler::Label fail(assembler_.get());
assembler_->Branch(
assembler_->Word32Equal(
assembler_->Word32And(FromId(value), assembler_->Int32Constant(mask)),
assembler_->Int32Constant(0)),
&fail, &pass);
assembler_->Bind(&fail);
assembler_->Return(assembler_->NullConstant());
assembler_->Bind(&pass);
}
void FastAccessorAssembler::CheckNotZeroOrReturnNull(ValueId value) {
CHECK_EQ(kBuilding, state_);
CodeStubAssembler::Label is_null(assembler_.get());
CodeStubAssembler::Label not_null(assembler_.get());
assembler_->Branch(
assembler_->WordEqual(FromId(value), assembler_->IntPtrConstant(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 CodeStubAssembler::Label(assembler_.get()));
}
void FastAccessorAssembler::SetLabel(LabelId label_id) {
CHECK_EQ(kBuilding, state_);
assembler_->Bind(FromId(label_id));
}
void FastAccessorAssembler::CheckNotZeroOrJump(ValueId value_id,
LabelId label_id) {
CHECK_EQ(kBuilding, state_);
CodeStubAssembler::Label pass(assembler_.get());
assembler_->Branch(
assembler_->WordEqual(FromId(value_id), assembler_->IntPtrConstant(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.
CallApiCallbackStub stub(isolate(), 1, true, true);
DCHECK_EQ(5, stub.GetCallInterfaceDescriptor().GetParameterCount());
DCHECK_EQ(1, stub.GetCallInterfaceDescriptor().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 context_parameter = 3;
Node* call = assembler_->CallStub(
stub.GetCallInterfaceDescriptor(),
assembler_->HeapConstant(stub.GetCode()),
assembler_->Parameter(context_parameter),
// Stub/register parameters:
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 */
// JS arguments, on stack:
FromId(arg));
return FromRaw(call);
}
void FastAccessorAssembler::CheckIsJSObjectOrJump(ValueId value_id,
LabelId label_id) {
CHECK_EQ(kBuilding, state_);
// Determine the 'value' object's instance type.
Node* object_map = assembler_->LoadObjectField(
FromId(value_id), Internals::kHeapObjectMapOffset,
MachineType::Pointer());
Node* instance_type = assembler_->WordAnd(
assembler_->LoadObjectField(object_map,
Internals::kMapInstanceTypeAndBitFieldOffset,
MachineType::Uint16()),
assembler_->IntPtrConstant(0xff));
CodeStubAssembler::Label is_jsobject(assembler_.get());
// Check whether we have a proper JSObject.
assembler_->GotoIf(
assembler_->WordEqual(
instance_type, assembler_->IntPtrConstant(Internals::kJSObjectType)),
&is_jsobject);
// JSApiObject?.
assembler_->GotoUnless(
assembler_->WordEqual(instance_type, assembler_->IntPtrConstant(
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 = assembler_->GenerateCode();
state_ = !code.is_null() ? kBuilt : kError;
Clear();
return code;
}
FastAccessorAssembler::ValueId FastAccessorAssembler::FromRaw(Node* node) {
nodes_.push_back(node);
ValueId value = {nodes_.size() - 1};
return value;
}
FastAccessorAssembler::LabelId FastAccessorAssembler::FromRaw(
CodeStubAssembler::Label* 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);
}
CodeStubAssembler::Label* 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