src/fast-accessor-assembler.cc - v8/v8.git - Git at Google

 // 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()));
 }

 FastAccessorAssembler::ValueId FastAccessorAssembler::ToSmi(ValueId value) {
   CHECK_EQ(kBuilding, state_);
   return FromRaw(assembler_->SmiTag(FromId(value)));
 }

 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::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_);
   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
	// 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()));
	}

	FastAccessorAssembler::ValueId FastAccessorAssembler::ToSmi(ValueId value) {
	CHECK_EQ(kBuilding, state_);
	return FromRaw(assembler_->SmiTag(FromId(value)));
	}

	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::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_);
	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