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// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "codegen.h"
#include "deoptimizer.h"
#include "disasm.h"
#include "full-codegen.h"
#include "global-handles.h"
#include "macro-assembler.h"
#include "prettyprinter.h"
namespace v8 {
namespace internal {
DeoptimizerData::DeoptimizerData() {
eager_deoptimization_entry_code_ = NULL;
lazy_deoptimization_entry_code_ = NULL;
current_ = NULL;
deoptimizing_code_list_ = NULL;
#ifdef ENABLE_DEBUGGER_SUPPORT
deoptimized_frame_info_ = NULL;
#endif
}
DeoptimizerData::~DeoptimizerData() {
if (eager_deoptimization_entry_code_ != NULL) {
eager_deoptimization_entry_code_->Free(EXECUTABLE);
eager_deoptimization_entry_code_ = NULL;
}
if (lazy_deoptimization_entry_code_ != NULL) {
lazy_deoptimization_entry_code_->Free(EXECUTABLE);
lazy_deoptimization_entry_code_ = NULL;
}
}
#ifdef ENABLE_DEBUGGER_SUPPORT
void DeoptimizerData::Iterate(ObjectVisitor* v) {
if (deoptimized_frame_info_ != NULL) {
deoptimized_frame_info_->Iterate(v);
}
}
#endif
Deoptimizer* Deoptimizer::New(JSFunction* function,
BailoutType type,
unsigned bailout_id,
Address from,
int fp_to_sp_delta,
Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
Deoptimizer* deoptimizer = new Deoptimizer(isolate,
function,
type,
bailout_id,
from,
fp_to_sp_delta,
NULL);
ASSERT(isolate->deoptimizer_data()->current_ == NULL);
isolate->deoptimizer_data()->current_ = deoptimizer;
return deoptimizer;
}
Deoptimizer* Deoptimizer::Grab(Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
Deoptimizer* result = isolate->deoptimizer_data()->current_;
ASSERT(result != NULL);
result->DeleteFrameDescriptions();
isolate->deoptimizer_data()->current_ = NULL;
return result;
}
#ifdef ENABLE_DEBUGGER_SUPPORT
DeoptimizedFrameInfo* Deoptimizer::DebuggerInspectableFrame(
JavaScriptFrame* frame,
int frame_index,
Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
ASSERT(frame->is_optimized());
ASSERT(isolate->deoptimizer_data()->deoptimized_frame_info_ == NULL);
// Get the function and code from the frame.
JSFunction* function = JSFunction::cast(frame->function());
Code* code = frame->LookupCode();
Address code_start_address = code->instruction_start();
// Locate the deoptimization point in the code. As we are at a call the
// return address must be at a place in the code with deoptimization support.
int deoptimization_index = Safepoint::kNoDeoptimizationIndex;
// Scope this as the safe point constructor will disallow allocation.
{
SafepointTable table(code);
for (unsigned i = 0; i < table.length(); ++i) {
Address address = code_start_address + table.GetPcOffset(i);
if (address == frame->pc()) {
SafepointEntry safepoint_entry = table.GetEntry(i);
ASSERT(safepoint_entry.deoptimization_index() !=
Safepoint::kNoDeoptimizationIndex);
deoptimization_index = safepoint_entry.deoptimization_index();
break;
}
}
}
ASSERT(deoptimization_index != Safepoint::kNoDeoptimizationIndex);
// Always use the actual stack slots when calculating the fp to sp
// delta adding two for the function and context.
unsigned stack_slots = code->stack_slots();
unsigned fp_to_sp_delta = ((stack_slots + 2) * kPointerSize);
Deoptimizer* deoptimizer = new Deoptimizer(isolate,
function,
Deoptimizer::DEBUGGER,
deoptimization_index,
frame->pc(),
fp_to_sp_delta,
code);
Address tos = frame->fp() - fp_to_sp_delta;
deoptimizer->FillInputFrame(tos, frame);
// Calculate the output frames.
Deoptimizer::ComputeOutputFrames(deoptimizer);
// Create the GC safe output frame information and register it for GC
// handling.
ASSERT_LT(frame_index, deoptimizer->output_count());
DeoptimizedFrameInfo* info =
new DeoptimizedFrameInfo(deoptimizer, frame_index);
isolate->deoptimizer_data()->deoptimized_frame_info_ = info;
// Get the "simulated" top and size for the requested frame.
Address top =
reinterpret_cast<Address>(deoptimizer->output_[frame_index]->GetTop());
uint32_t size = deoptimizer->output_[frame_index]->GetFrameSize();
// Done with the GC-unsafe frame descriptions. This re-enables allocation.
deoptimizer->DeleteFrameDescriptions();
// Allocate a heap number for the doubles belonging to this frame.
deoptimizer->MaterializeHeapNumbersForDebuggerInspectableFrame(
top, size, info);
// Finished using the deoptimizer instance.
delete deoptimizer;
return info;
}
void Deoptimizer::DeleteDebuggerInspectableFrame(DeoptimizedFrameInfo* info,
Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
ASSERT(isolate->deoptimizer_data()->deoptimized_frame_info_ == info);
delete info;
isolate->deoptimizer_data()->deoptimized_frame_info_ = NULL;
}
#endif
void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
int count,
BailoutType type) {
TableEntryGenerator generator(masm, type, count);
generator.Generate();
}
class DeoptimizingVisitor : public OptimizedFunctionVisitor {
public:
virtual void EnterContext(Context* context) {
if (FLAG_trace_deopt) {
PrintF("[deoptimize context: %" V8PRIxPTR "]\n",
reinterpret_cast<intptr_t>(context));
}
}
virtual void VisitFunction(JSFunction* function) {
Deoptimizer::DeoptimizeFunction(function);
}
virtual void LeaveContext(Context* context) {
context->ClearOptimizedFunctions();
}
};
void Deoptimizer::DeoptimizeAll() {
AssertNoAllocation no_allocation;
if (FLAG_trace_deopt) {
PrintF("[deoptimize all contexts]\n");
}
DeoptimizingVisitor visitor;
VisitAllOptimizedFunctions(&visitor);
}
void Deoptimizer::DeoptimizeGlobalObject(JSObject* object) {
AssertNoAllocation no_allocation;
DeoptimizingVisitor visitor;
VisitAllOptimizedFunctionsForGlobalObject(object, &visitor);
}
void Deoptimizer::VisitAllOptimizedFunctionsForContext(
Context* context, OptimizedFunctionVisitor* visitor) {
AssertNoAllocation no_allocation;
ASSERT(context->IsGlobalContext());
visitor->EnterContext(context);
// Run through the list of optimized functions and deoptimize them.
Object* element = context->OptimizedFunctionsListHead();
while (!element->IsUndefined()) {
JSFunction* element_function = JSFunction::cast(element);
// Get the next link before deoptimizing as deoptimizing will clear the
// next link.
element = element_function->next_function_link();
visitor->VisitFunction(element_function);
}
visitor->LeaveContext(context);
}
void Deoptimizer::VisitAllOptimizedFunctionsForGlobalObject(
JSObject* object, OptimizedFunctionVisitor* visitor) {
AssertNoAllocation no_allocation;
if (object->IsJSGlobalProxy()) {
Object* proto = object->GetPrototype();
ASSERT(proto->IsJSGlobalObject());
VisitAllOptimizedFunctionsForContext(
GlobalObject::cast(proto)->global_context(), visitor);
} else if (object->IsGlobalObject()) {
VisitAllOptimizedFunctionsForContext(
GlobalObject::cast(object)->global_context(), visitor);
}
}
void Deoptimizer::VisitAllOptimizedFunctions(
OptimizedFunctionVisitor* visitor) {
AssertNoAllocation no_allocation;
// Run through the list of all global contexts and deoptimize.
Object* global = Isolate::Current()->heap()->global_contexts_list();
while (!global->IsUndefined()) {
VisitAllOptimizedFunctionsForGlobalObject(Context::cast(global)->global(),
visitor);
global = Context::cast(global)->get(Context::NEXT_CONTEXT_LINK);
}
}
void Deoptimizer::HandleWeakDeoptimizedCode(
v8::Persistent<v8::Value> obj, void* data) {
DeoptimizingCodeListNode* node =
reinterpret_cast<DeoptimizingCodeListNode*>(data);
RemoveDeoptimizingCode(*node->code());
#ifdef DEBUG
node = Isolate::Current()->deoptimizer_data()->deoptimizing_code_list_;
while (node != NULL) {
ASSERT(node != reinterpret_cast<DeoptimizingCodeListNode*>(data));
node = node->next();
}
#endif
}
void Deoptimizer::ComputeOutputFrames(Deoptimizer* deoptimizer) {
deoptimizer->DoComputeOutputFrames();
}
Deoptimizer::Deoptimizer(Isolate* isolate,
JSFunction* function,
BailoutType type,
unsigned bailout_id,
Address from,
int fp_to_sp_delta,
Code* optimized_code)
: isolate_(isolate),
function_(function),
bailout_id_(bailout_id),
bailout_type_(type),
from_(from),
fp_to_sp_delta_(fp_to_sp_delta),
input_(NULL),
output_count_(0),
output_(NULL),
deferred_heap_numbers_(0) {
if (FLAG_trace_deopt && type != OSR) {
if (type == DEBUGGER) {
PrintF("**** DEOPT FOR DEBUGGER: ");
} else {
PrintF("**** DEOPT: ");
}
function->PrintName();
PrintF(" at bailout #%u, address 0x%" V8PRIxPTR ", frame size %d\n",
bailout_id,
reinterpret_cast<intptr_t>(from),
fp_to_sp_delta - (2 * kPointerSize));
} else if (FLAG_trace_osr && type == OSR) {
PrintF("**** OSR: ");
function->PrintName();
PrintF(" at ast id #%u, address 0x%" V8PRIxPTR ", frame size %d\n",
bailout_id,
reinterpret_cast<intptr_t>(from),
fp_to_sp_delta - (2 * kPointerSize));
}
// Find the optimized code.
if (type == EAGER) {
ASSERT(from == NULL);
optimized_code_ = function_->code();
} else if (type == LAZY) {
optimized_code_ = FindDeoptimizingCodeFromAddress(from);
ASSERT(optimized_code_ != NULL);
} else if (type == OSR) {
// The function has already been optimized and we're transitioning
// from the unoptimized shared version to the optimized one in the
// function. The return address (from) points to unoptimized code.
optimized_code_ = function_->code();
ASSERT(optimized_code_->kind() == Code::OPTIMIZED_FUNCTION);
ASSERT(!optimized_code_->contains(from));
} else if (type == DEBUGGER) {
optimized_code_ = optimized_code;
ASSERT(optimized_code_->contains(from));
}
ASSERT(HEAP->allow_allocation(false));
unsigned size = ComputeInputFrameSize();
input_ = new(size) FrameDescription(size, function);
#ifdef DEBUG
input_->SetKind(Code::OPTIMIZED_FUNCTION);
#endif
}
Deoptimizer::~Deoptimizer() {
ASSERT(input_ == NULL && output_ == NULL);
}
void Deoptimizer::DeleteFrameDescriptions() {
delete input_;
for (int i = 0; i < output_count_; ++i) {
if (output_[i] != input_) delete output_[i];
}
delete[] output_;
input_ = NULL;
output_ = NULL;
ASSERT(!HEAP->allow_allocation(true));
}
Address Deoptimizer::GetDeoptimizationEntry(int id, BailoutType type) {
ASSERT(id >= 0);
if (id >= kNumberOfEntries) return NULL;
LargeObjectChunk* base = NULL;
DeoptimizerData* data = Isolate::Current()->deoptimizer_data();
if (type == EAGER) {
if (data->eager_deoptimization_entry_code_ == NULL) {
data->eager_deoptimization_entry_code_ = CreateCode(type);
}
base = data->eager_deoptimization_entry_code_;
} else {
if (data->lazy_deoptimization_entry_code_ == NULL) {
data->lazy_deoptimization_entry_code_ = CreateCode(type);
}
base = data->lazy_deoptimization_entry_code_;
}
return
static_cast<Address>(base->GetStartAddress()) + (id * table_entry_size_);
}
int Deoptimizer::GetDeoptimizationId(Address addr, BailoutType type) {
LargeObjectChunk* base = NULL;
DeoptimizerData* data = Isolate::Current()->deoptimizer_data();
if (type == EAGER) {
base = data->eager_deoptimization_entry_code_;
} else {
base = data->lazy_deoptimization_entry_code_;
}
if (base == NULL ||
addr < base->GetStartAddress() ||
addr >= base->GetStartAddress() +
(kNumberOfEntries * table_entry_size_)) {
return kNotDeoptimizationEntry;
}
ASSERT_EQ(0,
static_cast<int>(addr - base->GetStartAddress()) % table_entry_size_);
return static_cast<int>(addr - base->GetStartAddress()) / table_entry_size_;
}
int Deoptimizer::GetOutputInfo(DeoptimizationOutputData* data,
unsigned id,
SharedFunctionInfo* shared) {
// TODO(kasperl): For now, we do a simple linear search for the PC
// offset associated with the given node id. This should probably be
// changed to a binary search.
int length = data->DeoptPoints();
Smi* smi_id = Smi::FromInt(id);
for (int i = 0; i < length; i++) {
if (data->AstId(i) == smi_id) {
return data->PcAndState(i)->value();
}
}
PrintF("[couldn't find pc offset for node=%u]\n", id);
PrintF("[method: %s]\n", *shared->DebugName()->ToCString());
// Print the source code if available.
HeapStringAllocator string_allocator;
StringStream stream(&string_allocator);
shared->SourceCodePrint(&stream, -1);
PrintF("[source:\n%s\n]", *stream.ToCString());
UNREACHABLE();
return -1;
}
int Deoptimizer::GetDeoptimizedCodeCount(Isolate* isolate) {
int length = 0;
DeoptimizingCodeListNode* node =
isolate->deoptimizer_data()->deoptimizing_code_list_;
while (node != NULL) {
length++;
node = node->next();
}
return length;
}
void Deoptimizer::DoComputeOutputFrames() {
if (bailout_type_ == OSR) {
DoComputeOsrOutputFrame();
return;
}
// Print some helpful diagnostic information.
int64_t start = OS::Ticks();
if (FLAG_trace_deopt) {
PrintF("[deoptimizing%s: begin 0x%08" V8PRIxPTR " ",
(bailout_type_ == LAZY ? " (lazy)" : ""),
reinterpret_cast<intptr_t>(function_));
function_->PrintName();
PrintF(" @%d]\n", bailout_id_);
}
// Determine basic deoptimization information. The optimized frame is
// described by the input data.
DeoptimizationInputData* input_data =
DeoptimizationInputData::cast(optimized_code_->deoptimization_data());
unsigned node_id = input_data->AstId(bailout_id_)->value();
ByteArray* translations = input_data->TranslationByteArray();
unsigned translation_index =
input_data->TranslationIndex(bailout_id_)->value();
// Do the input frame to output frame(s) translation.
TranslationIterator iterator(translations, translation_index);
Translation::Opcode opcode =
static_cast<Translation::Opcode>(iterator.Next());
ASSERT(Translation::BEGIN == opcode);
USE(opcode);
// Read the number of output frames and allocate an array for their
// descriptions.
int count = iterator.Next();
ASSERT(output_ == NULL);
output_ = new FrameDescription*[count];
for (int i = 0; i < count; ++i) {
output_[i] = NULL;
}
output_count_ = count;
// Translate each output frame.
for (int i = 0; i < count; ++i) {
DoComputeFrame(&iterator, i);
}
// Print some helpful diagnostic information.
if (FLAG_trace_deopt) {
double ms = static_cast<double>(OS::Ticks() - start) / 1000;
int index = output_count_ - 1; // Index of the topmost frame.
JSFunction* function = output_[index]->GetFunction();
PrintF("[deoptimizing: end 0x%08" V8PRIxPTR " ",
reinterpret_cast<intptr_t>(function));
function->PrintName();
PrintF(" => node=%u, pc=0x%08" V8PRIxPTR ", state=%s, took %0.3f ms]\n",
node_id,
output_[index]->GetPc(),
FullCodeGenerator::State2String(
static_cast<FullCodeGenerator::State>(
output_[index]->GetState()->value())),
ms);
}
}
void Deoptimizer::MaterializeHeapNumbers() {
ASSERT_NE(DEBUGGER, bailout_type_);
for (int i = 0; i < deferred_heap_numbers_.length(); i++) {
HeapNumberMaterializationDescriptor d = deferred_heap_numbers_[i];
Handle<Object> num = isolate_->factory()->NewNumber(d.value());
if (FLAG_trace_deopt) {
PrintF("Materializing a new heap number %p [%e] in slot %p\n",
reinterpret_cast<void*>(*num),
d.value(),
d.slot_address());
}
Memory::Object_at(d.slot_address()) = *num;
}
}
#ifdef ENABLE_DEBUGGER_SUPPORT
void Deoptimizer::MaterializeHeapNumbersForDebuggerInspectableFrame(
Address top, uint32_t size, DeoptimizedFrameInfo* info) {
ASSERT_EQ(DEBUGGER, bailout_type_);
for (int i = 0; i < deferred_heap_numbers_.length(); i++) {
HeapNumberMaterializationDescriptor d = deferred_heap_numbers_[i];
// Check of the heap number to materialize actually belong to the frame
// being extracted.
Address slot = d.slot_address();
if (top <= slot && slot < top + size) {
Handle<Object> num = isolate_->factory()->NewNumber(d.value());
// Calculate the index with the botton of the expression stack
// at index 0, and the fixed part (including incoming arguments)
// at negative indexes.
int index = static_cast<int>(
info->expression_count_ - (slot - top) / kPointerSize - 1);
if (FLAG_trace_deopt) {
PrintF("Materializing a new heap number %p [%e] in slot %p"
"for stack index %d\n",
reinterpret_cast<void*>(*num),
d.value(),
d.slot_address(),
index);
}
if (index >=0) {
info->SetExpression(index, *num);
} else {
// Calculate parameter index subtracting one for the receiver.
int parameter_index =
index +
static_cast<int>(size) / kPointerSize -
info->expression_count_ - 1;
info->SetParameter(parameter_index, *num);
}
}
}
}
#endif
void Deoptimizer::DoTranslateCommand(TranslationIterator* iterator,
int frame_index,
unsigned output_offset) {
disasm::NameConverter converter;
// A GC-safe temporary placeholder that we can put in the output frame.
const intptr_t kPlaceholder = reinterpret_cast<intptr_t>(Smi::FromInt(0));
// Ignore commands marked as duplicate and act on the first non-duplicate.
Translation::Opcode opcode =
static_cast<Translation::Opcode>(iterator->Next());
while (opcode == Translation::DUPLICATE) {
opcode = static_cast<Translation::Opcode>(iterator->Next());
iterator->Skip(Translation::NumberOfOperandsFor(opcode));
opcode = static_cast<Translation::Opcode>(iterator->Next());
}
switch (opcode) {
case Translation::BEGIN:
case Translation::FRAME:
case Translation::DUPLICATE:
UNREACHABLE();
return;
case Translation::REGISTER: {
int input_reg = iterator->Next();
intptr_t input_value = input_->GetRegister(input_reg);
if (FLAG_trace_deopt) {
PrintF(
" 0x%08" V8PRIxPTR ": [top + %d] <- 0x%08" V8PRIxPTR " ; %s ",
output_[frame_index]->GetTop() + output_offset,
output_offset,
input_value,
converter.NameOfCPURegister(input_reg));
reinterpret_cast<Object*>(input_value)->ShortPrint();
PrintF("\n");
}
output_[frame_index]->SetFrameSlot(output_offset, input_value);
return;
}
case Translation::INT32_REGISTER: {
int input_reg = iterator->Next();
intptr_t value = input_->GetRegister(input_reg);
bool is_smi = Smi::IsValid(value);
if (FLAG_trace_deopt) {
PrintF(
" 0x%08" V8PRIxPTR ": [top + %d] <- %" V8PRIdPTR " ; %s (%s)\n",
output_[frame_index]->GetTop() + output_offset,
output_offset,
value,
converter.NameOfCPURegister(input_reg),
is_smi ? "smi" : "heap number");
}
if (is_smi) {
intptr_t tagged_value =
reinterpret_cast<intptr_t>(Smi::FromInt(static_cast<int>(value)));
output_[frame_index]->SetFrameSlot(output_offset, tagged_value);
} else {
// We save the untagged value on the side and store a GC-safe
// temporary placeholder in the frame.
AddDoubleValue(output_[frame_index]->GetTop() + output_offset,
static_cast<double>(static_cast<int32_t>(value)));
output_[frame_index]->SetFrameSlot(output_offset, kPlaceholder);
}
return;
}
case Translation::DOUBLE_REGISTER: {
int input_reg = iterator->Next();
double value = input_->GetDoubleRegister(input_reg);
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": [top + %d] <- %e ; %s\n",
output_[frame_index]->GetTop() + output_offset,
output_offset,
value,
DoubleRegister::AllocationIndexToString(input_reg));
}
// We save the untagged value on the side and store a GC-safe
// temporary placeholder in the frame.
AddDoubleValue(output_[frame_index]->GetTop() + output_offset, value);
output_[frame_index]->SetFrameSlot(output_offset, kPlaceholder);
return;
}
case Translation::STACK_SLOT: {
int input_slot_index = iterator->Next();
unsigned input_offset =
input_->GetOffsetFromSlotIndex(this, input_slot_index);
intptr_t input_value = input_->GetFrameSlot(input_offset);
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": ",
output_[frame_index]->GetTop() + output_offset);
PrintF("[top + %d] <- 0x%08" V8PRIxPTR " ; [esp + %d] ",
output_offset,
input_value,
input_offset);
reinterpret_cast<Object*>(input_value)->ShortPrint();
PrintF("\n");
}
output_[frame_index]->SetFrameSlot(output_offset, input_value);
return;
}
case Translation::INT32_STACK_SLOT: {
int input_slot_index = iterator->Next();
unsigned input_offset =
input_->GetOffsetFromSlotIndex(this, input_slot_index);
intptr_t value = input_->GetFrameSlot(input_offset);
bool is_smi = Smi::IsValid(value);
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": ",
output_[frame_index]->GetTop() + output_offset);
PrintF("[top + %d] <- %" V8PRIdPTR " ; [esp + %d] (%s)\n",
output_offset,
value,
input_offset,
is_smi ? "smi" : "heap number");
}
if (is_smi) {
intptr_t tagged_value =
reinterpret_cast<intptr_t>(Smi::FromInt(static_cast<int>(value)));
output_[frame_index]->SetFrameSlot(output_offset, tagged_value);
} else {
// We save the untagged value on the side and store a GC-safe
// temporary placeholder in the frame.
AddDoubleValue(output_[frame_index]->GetTop() + output_offset,
static_cast<double>(static_cast<int32_t>(value)));
output_[frame_index]->SetFrameSlot(output_offset, kPlaceholder);
}
return;
}
case Translation::DOUBLE_STACK_SLOT: {
int input_slot_index = iterator->Next();
unsigned input_offset =
input_->GetOffsetFromSlotIndex(this, input_slot_index);
double value = input_->GetDoubleFrameSlot(input_offset);
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": [top + %d] <- %e ; [esp + %d]\n",
output_[frame_index]->GetTop() + output_offset,
output_offset,
value,
input_offset);
}
// We save the untagged value on the side and store a GC-safe
// temporary placeholder in the frame.
AddDoubleValue(output_[frame_index]->GetTop() + output_offset, value);
output_[frame_index]->SetFrameSlot(output_offset, kPlaceholder);
return;
}
case Translation::LITERAL: {
Object* literal = ComputeLiteral(iterator->Next());
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": [top + %d] <- ",
output_[frame_index]->GetTop() + output_offset,
output_offset);
literal->ShortPrint();
PrintF(" ; literal\n");
}
intptr_t value = reinterpret_cast<intptr_t>(literal);
output_[frame_index]->SetFrameSlot(output_offset, value);
return;
}
case Translation::ARGUMENTS_OBJECT: {
// Use the arguments marker value as a sentinel and fill in the arguments
// object after the deoptimized frame is built.
ASSERT(frame_index == 0); // Only supported for first frame.
if (FLAG_trace_deopt) {
PrintF(" 0x%08" V8PRIxPTR ": [top + %d] <- ",
output_[frame_index]->GetTop() + output_offset,
output_offset);
isolate_->heap()->arguments_marker()->ShortPrint();
PrintF(" ; arguments object\n");
}
intptr_t value = reinterpret_cast<intptr_t>(
isolate_->heap()->arguments_marker());
output_[frame_index]->SetFrameSlot(output_offset, value);
return;
}
}
}
bool Deoptimizer::DoOsrTranslateCommand(TranslationIterator* iterator,
int* input_offset) {
disasm::NameConverter converter;
FrameDescription* output = output_[0];
// The input values are all part of the unoptimized frame so they
// are all tagged pointers.
uintptr_t input_value = input_->GetFrameSlot(*input_offset);
Object* input_object = reinterpret_cast<Object*>(input_value);
Translation::Opcode opcode =
static_cast<Translation::Opcode>(iterator->Next());
bool duplicate = (opcode == Translation::DUPLICATE);
if (duplicate) {
opcode = static_cast<Translation::Opcode>(iterator->Next());
}
switch (opcode) {
case Translation::BEGIN:
case Translation::FRAME:
case Translation::DUPLICATE:
UNREACHABLE(); // Malformed input.
return false;
case Translation::REGISTER: {
int output_reg = iterator->Next();
if (FLAG_trace_osr) {
PrintF(" %s <- 0x%08" V8PRIxPTR " ; [sp + %d]\n",
converter.NameOfCPURegister(output_reg),
input_value,
*input_offset);
}
output->SetRegister(output_reg, input_value);
break;
}
case Translation::INT32_REGISTER: {
// Abort OSR if we don't have a number.
if (!input_object->IsNumber()) return false;
int output_reg = iterator->Next();
int int32_value = input_object->IsSmi()
? Smi::cast(input_object)->value()
: FastD2I(input_object->Number());
// Abort the translation if the conversion lost information.
if (!input_object->IsSmi() &&
FastI2D(int32_value) != input_object->Number()) {
if (FLAG_trace_osr) {
PrintF("**** %g could not be converted to int32 ****\n",
input_object->Number());
}
return false;
}
if (FLAG_trace_osr) {
PrintF(" %s <- %d (int32) ; [sp + %d]\n",
converter.NameOfCPURegister(output_reg),
int32_value,
*input_offset);
}
output->SetRegister(output_reg, int32_value);
break;
}
case Translation::DOUBLE_REGISTER: {
// Abort OSR if we don't have a number.
if (!input_object->IsNumber()) return false;
int output_reg = iterator->Next();
double double_value = input_object->Number();
if (FLAG_trace_osr) {
PrintF(" %s <- %g (double) ; [sp + %d]\n",
DoubleRegister::AllocationIndexToString(output_reg),
double_value,
*input_offset);
}
output->SetDoubleRegister(output_reg, double_value);
break;
}
case Translation::STACK_SLOT: {
int output_index = iterator->Next();
unsigned output_offset =
output->GetOffsetFromSlotIndex(this, output_index);
if (FLAG_trace_osr) {
PrintF(" [sp + %d] <- 0x%08" V8PRIxPTR " ; [sp + %d]\n",
output_offset,
input_value,
*input_offset);
}
output->SetFrameSlot(output_offset, input_value);
break;
}
case Translation::INT32_STACK_SLOT: {
// Abort OSR if we don't have a number.
if (!input_object->IsNumber()) return false;
int output_index = iterator->Next();
unsigned output_offset =
output->GetOffsetFromSlotIndex(this, output_index);
int int32_value = input_object->IsSmi()
? Smi::cast(input_object)->value()
: DoubleToInt32(input_object->Number());
// Abort the translation if the conversion lost information.
if (!input_object->IsSmi() &&
FastI2D(int32_value) != input_object->Number()) {
if (FLAG_trace_osr) {
PrintF("**** %g could not be converted to int32 ****\n",
input_object->Number());
}
return false;
}
if (FLAG_trace_osr) {
PrintF(" [sp + %d] <- %d (int32) ; [sp + %d]\n",
output_offset,
int32_value,
*input_offset);
}
output->SetFrameSlot(output_offset, int32_value);
break;
}
case Translation::DOUBLE_STACK_SLOT: {
static const int kLowerOffset = 0 * kPointerSize;
static const int kUpperOffset = 1 * kPointerSize;
// Abort OSR if we don't have a number.
if (!input_object->IsNumber()) return false;
int output_index = iterator->Next();
unsigned output_offset =
output->GetOffsetFromSlotIndex(this, output_index);
double double_value = input_object->Number();
uint64_t int_value = BitCast<uint64_t, double>(double_value);
int32_t lower = static_cast<int32_t>(int_value);
int32_t upper = static_cast<int32_t>(int_value >> kBitsPerInt);
if (FLAG_trace_osr) {
PrintF(" [sp + %d] <- 0x%08x (upper bits of %g) ; [sp + %d]\n",
output_offset + kUpperOffset,
upper,
double_value,
*input_offset);
PrintF(" [sp + %d] <- 0x%08x (lower bits of %g) ; [sp + %d]\n",
output_offset + kLowerOffset,
lower,
double_value,
*input_offset);
}
output->SetFrameSlot(output_offset + kLowerOffset, lower);
output->SetFrameSlot(output_offset + kUpperOffset, upper);
break;
}
case Translation::LITERAL: {
// Just ignore non-materialized literals.
iterator->Next();
break;
}
case Translation::ARGUMENTS_OBJECT: {
// Optimized code assumes that the argument object has not been
// materialized and so bypasses it when doing arguments access.
// We should have bailed out before starting the frame
// translation.
UNREACHABLE();
return false;
}
}
if (!duplicate) *input_offset -= kPointerSize;
return true;
}
void Deoptimizer::PatchStackCheckCode(Code* unoptimized_code,
Code* check_code,
Code* replacement_code) {
// Iterate over the stack check table and patch every stack check
// call to an unconditional call to the replacement code.
ASSERT(unoptimized_code->kind() == Code::FUNCTION);
Address stack_check_cursor = unoptimized_code->instruction_start() +
unoptimized_code->stack_check_table_offset();
uint32_t table_length = Memory::uint32_at(stack_check_cursor);
stack_check_cursor += kIntSize;
for (uint32_t i = 0; i < table_length; ++i) {
uint32_t pc_offset = Memory::uint32_at(stack_check_cursor + kIntSize);
Address pc_after = unoptimized_code->instruction_start() + pc_offset;
PatchStackCheckCodeAt(pc_after, check_code, replacement_code);
stack_check_cursor += 2 * kIntSize;
}
}
void Deoptimizer::RevertStackCheckCode(Code* unoptimized_code,
Code* check_code,
Code* replacement_code) {
// Iterate over the stack check table and revert the patched
// stack check calls.
ASSERT(unoptimized_code->kind() == Code::FUNCTION);
Address stack_check_cursor = unoptimized_code->instruction_start() +
unoptimized_code->stack_check_table_offset();
uint32_t table_length = Memory::uint32_at(stack_check_cursor);
stack_check_cursor += kIntSize;
for (uint32_t i = 0; i < table_length; ++i) {
uint32_t pc_offset = Memory::uint32_at(stack_check_cursor + kIntSize);
Address pc_after = unoptimized_code->instruction_start() + pc_offset;
RevertStackCheckCodeAt(pc_after, check_code, replacement_code);
stack_check_cursor += 2 * kIntSize;
}
}
unsigned Deoptimizer::ComputeInputFrameSize() const {
unsigned fixed_size = ComputeFixedSize(function_);
// The fp-to-sp delta already takes the context and the function
// into account so we have to avoid double counting them (-2).
unsigned result = fixed_size + fp_to_sp_delta_ - (2 * kPointerSize);
#ifdef DEBUG
if (bailout_type_ == OSR) {
// TODO(kasperl): It would be nice if we could verify that the
// size matches with the stack height we can compute based on the
// environment at the OSR entry. The code for that his built into
// the DoComputeOsrOutputFrame function for now.
} else {
unsigned stack_slots = optimized_code_->stack_slots();
unsigned outgoing_size = ComputeOutgoingArgumentSize();
ASSERT(result == fixed_size + (stack_slots * kPointerSize) + outgoing_size);
}
#endif
return result;
}
unsigned Deoptimizer::ComputeFixedSize(JSFunction* function) const {
// The fixed part of the frame consists of the return address, frame
// pointer, function, context, and all the incoming arguments.
static const unsigned kFixedSlotSize = 4 * kPointerSize;
return ComputeIncomingArgumentSize(function) + kFixedSlotSize;
}
unsigned Deoptimizer::ComputeIncomingArgumentSize(JSFunction* function) const {
// The incoming arguments is the values for formal parameters and
// the receiver. Every slot contains a pointer.
unsigned arguments = function->shared()->formal_parameter_count() + 1;
return arguments * kPointerSize;
}
unsigned Deoptimizer::ComputeOutgoingArgumentSize() const {
DeoptimizationInputData* data = DeoptimizationInputData::cast(
optimized_code_->deoptimization_data());
unsigned height = data->ArgumentsStackHeight(bailout_id_)->value();
return height * kPointerSize;
}
Object* Deoptimizer::ComputeLiteral(int index) const {
DeoptimizationInputData* data = DeoptimizationInputData::cast(
optimized_code_->deoptimization_data());
FixedArray* literals = data->LiteralArray();
return literals->get(index);
}
void Deoptimizer::AddDoubleValue(intptr_t slot_address,
double value) {
HeapNumberMaterializationDescriptor value_desc(
reinterpret_cast<Address>(slot_address), value);
deferred_heap_numbers_.Add(value_desc);
}
LargeObjectChunk* Deoptimizer::CreateCode(BailoutType type) {
// We cannot run this if the serializer is enabled because this will
// cause us to emit relocation information for the external
// references. This is fine because the deoptimizer's code section
// isn't meant to be serialized at all.
ASSERT(!Serializer::enabled());
MacroAssembler masm(Isolate::Current(), NULL, 16 * KB);
masm.set_emit_debug_code(false);
GenerateDeoptimizationEntries(&masm, kNumberOfEntries, type);
CodeDesc desc;
masm.GetCode(&desc);
ASSERT(desc.reloc_size == 0);
LargeObjectChunk* chunk = LargeObjectChunk::New(desc.instr_size, EXECUTABLE);
if (chunk == NULL) {
V8::FatalProcessOutOfMemory("Not enough memory for deoptimization table");
}
memcpy(chunk->GetStartAddress(), desc.buffer, desc.instr_size);
CPU::FlushICache(chunk->GetStartAddress(), desc.instr_size);
return chunk;
}
Code* Deoptimizer::FindDeoptimizingCodeFromAddress(Address addr) {
DeoptimizingCodeListNode* node =
Isolate::Current()->deoptimizer_data()->deoptimizing_code_list_;
while (node != NULL) {
if (node->code()->contains(addr)) return *node->code();
node = node->next();
}
return NULL;
}
void Deoptimizer::RemoveDeoptimizingCode(Code* code) {
DeoptimizerData* data = Isolate::Current()->deoptimizer_data();
ASSERT(data->deoptimizing_code_list_ != NULL);
// Run through the code objects to find this one and remove it.
DeoptimizingCodeListNode* prev = NULL;
DeoptimizingCodeListNode* current = data->deoptimizing_code_list_;
while (current != NULL) {
if (*current->code() == code) {
// Unlink from list. If prev is NULL we are looking at the first element.
if (prev == NULL) {
data->deoptimizing_code_list_ = current->next();
} else {
prev->set_next(current->next());
}
delete current;
return;
}
// Move to next in list.
prev = current;
current = current->next();
}
// Deoptimizing code is removed through weak callback. Each object is expected
// to be removed once and only once.
UNREACHABLE();
}
FrameDescription::FrameDescription(uint32_t frame_size,
JSFunction* function)
: frame_size_(frame_size),
function_(function),
top_(kZapUint32),
pc_(kZapUint32),
fp_(kZapUint32) {
// Zap all the registers.
for (int r = 0; r < Register::kNumRegisters; r++) {
SetRegister(r, kZapUint32);
}
// Zap all the slots.
for (unsigned o = 0; o < frame_size; o += kPointerSize) {
SetFrameSlot(o, kZapUint32);
}
}
unsigned FrameDescription::GetOffsetFromSlotIndex(Deoptimizer* deoptimizer,
int slot_index) {
if (slot_index >= 0) {
// Local or spill slots. Skip the fixed part of the frame
// including all arguments.
unsigned base =
GetFrameSize() - deoptimizer->ComputeFixedSize(GetFunction());
return base - ((slot_index + 1) * kPointerSize);
} else {
// Incoming parameter.
unsigned base = GetFrameSize() -
deoptimizer->ComputeIncomingArgumentSize(GetFunction());
return base - ((slot_index + 1) * kPointerSize);
}
}
int FrameDescription::ComputeParametersCount() {
return function_->shared()->formal_parameter_count();
}
Object* FrameDescription::GetParameter(Deoptimizer* deoptimizer, int index) {
ASSERT_EQ(Code::FUNCTION, kind_);
ASSERT(index >= 0);
ASSERT(index < ComputeParametersCount());
// The slot indexes for incoming arguments are negative.
unsigned offset = GetOffsetFromSlotIndex(deoptimizer,
index - ComputeParametersCount());
return reinterpret_cast<Object*>(*GetFrameSlotPointer(offset));
}
unsigned FrameDescription::GetExpressionCount(Deoptimizer* deoptimizer) {
ASSERT_EQ(Code::FUNCTION, kind_);
unsigned size = GetFrameSize() - deoptimizer->ComputeFixedSize(GetFunction());
return size / kPointerSize;
}
Object* FrameDescription::GetExpression(Deoptimizer* deoptimizer, int index) {
ASSERT_EQ(Code::FUNCTION, kind_);
unsigned offset = GetOffsetFromSlotIndex(deoptimizer, index);
return reinterpret_cast<Object*>(*GetFrameSlotPointer(offset));
}
void TranslationBuffer::Add(int32_t value) {
// Encode the sign bit in the least significant bit.
bool is_negative = (value < 0);
uint32_t bits = ((is_negative ? -value : value) << 1) |
static_cast<int32_t>(is_negative);
// Encode the individual bytes using the least significant bit of
// each byte to indicate whether or not more bytes follow.
do {
uint32_t next = bits >> 7;
contents_.Add(((bits << 1) & 0xFF) | (next != 0));
bits = next;
} while (bits != 0);
}
int32_t TranslationIterator::Next() {
// Run through the bytes until we reach one with a least significant
// bit of zero (marks the end).
uint32_t bits = 0;
for (int i = 0; true; i += 7) {
ASSERT(HasNext());
uint8_t next = buffer_->get(index_++);
bits |= (next >> 1) << i;
if ((next & 1) == 0) break;
}
// The bits encode the sign in the least significant bit.
bool is_negative = (bits & 1) == 1;
int32_t result = bits >> 1;
return is_negative ? -result : result;
}
Handle<ByteArray> TranslationBuffer::CreateByteArray() {
int length = contents_.length();
Handle<ByteArray> result =
Isolate::Current()->factory()->NewByteArray(length, TENURED);
memcpy(result->GetDataStartAddress(), contents_.ToVector().start(), length);
return result;
}
void Translation::BeginFrame(int node_id, int literal_id, unsigned height) {
buffer_->Add(FRAME);
buffer_->Add(node_id);
buffer_->Add(literal_id);
buffer_->Add(height);
}
void Translation::StoreRegister(Register reg) {
buffer_->Add(REGISTER);
buffer_->Add(reg.code());
}
void Translation::StoreInt32Register(Register reg) {
buffer_->Add(INT32_REGISTER);
buffer_->Add(reg.code());
}
void Translation::StoreDoubleRegister(DoubleRegister reg) {
buffer_->Add(DOUBLE_REGISTER);
buffer_->Add(DoubleRegister::ToAllocationIndex(reg));
}
void Translation::StoreStackSlot(int index) {
buffer_->Add(STACK_SLOT);
buffer_->Add(index);
}
void Translation::StoreInt32StackSlot(int index) {
buffer_->Add(INT32_STACK_SLOT);
buffer_->Add(index);
}
void Translation::StoreDoubleStackSlot(int index) {
buffer_->Add(DOUBLE_STACK_SLOT);
buffer_->Add(index);
}
void Translation::StoreLiteral(int literal_id) {
buffer_->Add(LITERAL);
buffer_->Add(literal_id);
}
void Translation::StoreArgumentsObject() {
buffer_->Add(ARGUMENTS_OBJECT);
}
void Translation::MarkDuplicate() {
buffer_->Add(DUPLICATE);
}
int Translation::NumberOfOperandsFor(Opcode opcode) {
switch (opcode) {
case ARGUMENTS_OBJECT:
case DUPLICATE:
return 0;
case BEGIN:
case REGISTER:
case INT32_REGISTER:
case DOUBLE_REGISTER:
case STACK_SLOT:
case INT32_STACK_SLOT:
case DOUBLE_STACK_SLOT:
case LITERAL:
return 1;
case FRAME:
return 3;
}
UNREACHABLE();
return -1;
}
#if defined(OBJECT_PRINT) || defined(ENABLE_DISASSEMBLER)
const char* Translation::StringFor(Opcode opcode) {
switch (opcode) {
case BEGIN:
return "BEGIN";
case FRAME:
return "FRAME";
case REGISTER:
return "REGISTER";
case INT32_REGISTER:
return "INT32_REGISTER";
case DOUBLE_REGISTER:
return "DOUBLE_REGISTER";
case STACK_SLOT:
return "STACK_SLOT";
case INT32_STACK_SLOT:
return "INT32_STACK_SLOT";
case DOUBLE_STACK_SLOT:
return "DOUBLE_STACK_SLOT";
case LITERAL:
return "LITERAL";
case ARGUMENTS_OBJECT:
return "ARGUMENTS_OBJECT";
case DUPLICATE:
return "DUPLICATE";
}
UNREACHABLE();
return "";
}
#endif
DeoptimizingCodeListNode::DeoptimizingCodeListNode(Code* code): next_(NULL) {
GlobalHandles* global_handles = Isolate::Current()->global_handles();
// Globalize the code object and make it weak.
code_ = Handle<Code>::cast(global_handles->Create(code));
global_handles->MakeWeak(reinterpret_cast<Object**>(code_.location()),
this,
Deoptimizer::HandleWeakDeoptimizedCode);
}
DeoptimizingCodeListNode::~DeoptimizingCodeListNode() {
GlobalHandles* global_handles = Isolate::Current()->global_handles();
global_handles->Destroy(reinterpret_cast<Object**>(code_.location()));
}
// We can't intermix stack decoding and allocations because
// deoptimization infrastracture is not GC safe.
// Thus we build a temporary structure in malloced space.
SlotRef SlotRef::ComputeSlotForNextArgument(TranslationIterator* iterator,
DeoptimizationInputData* data,
JavaScriptFrame* frame) {
Translation::Opcode opcode =
static_cast<Translation::Opcode>(iterator->Next());
switch (opcode) {
case Translation::BEGIN:
case Translation::FRAME:
// Peeled off before getting here.
break;
case Translation::ARGUMENTS_OBJECT:
// This can be only emitted for local slots not for argument slots.
break;
case Translation::REGISTER:
case Translation::INT32_REGISTER:
case Translation::DOUBLE_REGISTER:
case Translation::DUPLICATE:
// We are at safepoint which corresponds to call. All registers are
// saved by caller so there would be no live registers at this
// point. Thus these translation commands should not be used.
break;
case Translation::STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::TAGGED);
}
case Translation::INT32_STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::INT32);
}
case Translation::DOUBLE_STACK_SLOT: {
int slot_index = iterator->Next();
Address slot_addr = SlotAddress(frame, slot_index);
return SlotRef(slot_addr, SlotRef::DOUBLE);
}
case Translation::LITERAL: {
int literal_index = iterator->Next();
return SlotRef(data->LiteralArray()->get(literal_index));
}
}
UNREACHABLE();
return SlotRef();
}
void SlotRef::ComputeSlotMappingForArguments(JavaScriptFrame* frame,
int inlined_frame_index,
Vector<SlotRef>* args_slots) {
AssertNoAllocation no_gc;
int deopt_index = AstNode::kNoNumber;
DeoptimizationInputData* data =
static_cast<OptimizedFrame*>(frame)->GetDeoptimizationData(&deopt_index);
TranslationIterator it(data->TranslationByteArray(),
data->TranslationIndex(deopt_index)->value());
Translation::Opcode opcode = static_cast<Translation::Opcode>(it.Next());
ASSERT(opcode == Translation::BEGIN);
int frame_count = it.Next();
USE(frame_count);
ASSERT(frame_count > inlined_frame_index);
int frames_to_skip = inlined_frame_index;
while (true) {
opcode = static_cast<Translation::Opcode>(it.Next());
// Skip over operands to advance to the next opcode.
it.Skip(Translation::NumberOfOperandsFor(opcode));
if (opcode == Translation::FRAME) {
if (frames_to_skip == 0) {
// We reached the frame corresponding to the inlined function
// in question. Process the translation commands for the
// arguments.
//
// Skip the translation command for the receiver.
it.Skip(Translation::NumberOfOperandsFor(
static_cast<Translation::Opcode>(it.Next())));
// Compute slots for arguments.
for (int i = 0; i < args_slots->length(); ++i) {
(*args_slots)[i] = ComputeSlotForNextArgument(&it, data, frame);
}
return;
}
frames_to_skip--;
}
}
UNREACHABLE();
}
#ifdef ENABLE_DEBUGGER_SUPPORT
DeoptimizedFrameInfo::DeoptimizedFrameInfo(
Deoptimizer* deoptimizer, int frame_index) {
FrameDescription* output_frame = deoptimizer->output_[frame_index];
SetFunction(output_frame->GetFunction());
expression_count_ = output_frame->GetExpressionCount(deoptimizer);
parameters_count_ = output_frame->ComputeParametersCount();
parameters_ = new Object*[parameters_count_];
for (int i = 0; i < parameters_count_; i++) {
SetParameter(i, output_frame->GetParameter(deoptimizer, i));
}
expression_stack_ = new Object*[expression_count_];
for (int i = 0; i < expression_count_; i++) {
SetExpression(i, output_frame->GetExpression(deoptimizer, i));
}
}
DeoptimizedFrameInfo::~DeoptimizedFrameInfo() {
delete[] expression_stack_;
delete[] parameters_;
}
void DeoptimizedFrameInfo::Iterate(ObjectVisitor* v) {
v->VisitPointer(BitCast<Object**>(&function_));
v->VisitPointers(parameters_, parameters_ + parameters_count_);
v->VisitPointers(expression_stack_, expression_stack_ + expression_count_);
}
#endif // ENABLE_DEBUGGER_SUPPORT
} } // namespace v8::internal