CSE2410 Fall 2014 Bounce

// Copyright 2012 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 "compiler.h"

#include "bootstrapper.h"

#include "codegen.h"

#include "compilation-cache.h"

#include "cpu-profiler.h"

#include "debug.h"

#include "deoptimizer.h"

#include "full-codegen.h"

#include "gdb-jit.h"

#include "typing.h"

#include "hydrogen.h"

#include "isolate-inl.h"

#include "lithium.h"

#include "liveedit.h"

#include "parser.h"

#include "rewriter.h"

#include "runtime-profiler.h"

#include "scanner-character-streams.h"

#include "scopeinfo.h"

#include "scopes.h"

#include "vm-state-inl.h"

namespace v8 {

namespace internal {

CompilationInfo::CompilationInfo(Handle<Script> script,

                                 Zone* zone)

    : flags_(LanguageModeField::encode(CLASSIC_MODE)),

      script_(script),

      osr_ast_id_(BailoutId::None()),

      osr_pc_offset_(0) {

  Initialize(script->GetIsolate(), BASE, zone);

}

CompilationInfo::CompilationInfo(Handle<SharedFunctionInfo> shared_info,

                                 Zone* zone)

    : flags_(LanguageModeField::encode(CLASSIC_MODE) | IsLazy::encode(true)),

      shared_info_(shared_info),

      script_(Handle<Script>(Script::cast(shared_info->script()))),

      osr_ast_id_(BailoutId::None()),

      osr_pc_offset_(0) {

  Initialize(script_->GetIsolate(), BASE, zone);

}

CompilationInfo::CompilationInfo(Handle<JSFunction> closure,

                                 Zone* zone)

    : flags_(LanguageModeField::encode(CLASSIC_MODE) | IsLazy::encode(true)),

      closure_(closure),

      shared_info_(Handle<SharedFunctionInfo>(closure->shared())),

      script_(Handle<Script>(Script::cast(shared_info_->script()))),

      context_(closure->context()),

      osr_ast_id_(BailoutId::None()),

      osr_pc_offset_(0) {

  Initialize(script_->GetIsolate(), BASE, zone);

}

CompilationInfo::CompilationInfo(HydrogenCodeStub* stub,

                                 Isolate* isolate,

                                 Zone* zone)

    : flags_(LanguageModeField::encode(CLASSIC_MODE) |

             IsLazy::encode(true)),

      osr_ast_id_(BailoutId::None()),

      osr_pc_offset_(0) {

  Initialize(isolate, STUB, zone);

  code_stub_ = stub;

}

void CompilationInfo::Initialize(Isolate* isolate,

                                 Mode mode,

                                 Zone* zone) {

  isolate_ = isolate;

  function_ = NULL;

  scope_ = NULL;

  global_scope_ = NULL;

  extension_ = NULL;

  pre_parse_data_ = NULL;

  zone_ = zone;

  deferred_handles_ = NULL;

  code_stub_ = NULL;

  prologue_offset_ = Code::kPrologueOffsetNotSet;

  opt_count_ = shared_info().is_null() ? 0 : shared_info()->opt_count();

  no_frame_ranges_ = isolate->cpu_profiler()->is_profiling()

                   ? new List<OffsetRange>(2) : NULL;

  for (int i = 0; i < DependentCode::kGroupCount; i++) {

    dependencies_[i] = NULL;

  }

  if (mode == STUB) {

    mode_ = STUB;

    return;

  }

  mode_ = mode;

  abort_due_to_dependency_ = false;

  if (script_->type()->value() == Script::TYPE_NATIVE) {

    MarkAsNative();

  }

  if (!shared_info_.is_null()) {

    ASSERT(language_mode() == CLASSIC_MODE);

    SetLanguageMode(shared_info_->language_mode());

  }

  set_bailout_reason(kUnknown);

}

CompilationInfo::~CompilationInfo() {

  delete deferred_handles_;

  delete no_frame_ranges_;

#ifdef DEBUG

  // Check that no dependent maps have been added or added dependent maps have

  // been rolled back or committed.

  for (int i = 0; i < DependentCode::kGroupCount; i++) {

    ASSERT_EQ(NULL, dependencies_[i]);

  }

#endif  // DEBUG

}

void CompilationInfo::CommitDependencies(Handle<Code> code) {

  for (int i = 0; i < DependentCode::kGroupCount; i++) {

    ZoneList<Handle<HeapObject> >* group_objects = dependencies_[i];

    if (group_objects == NULL) continue;

    ASSERT(!object_wrapper_.is_null());

    for (int j = 0; j < group_objects->length(); j++) {

      DependentCode::DependencyGroup group =

          static_cast<DependentCode::DependencyGroup>(i);

      DependentCode* dependent_code =

          DependentCode::ForObject(group_objects->at(j), group);

      dependent_code->UpdateToFinishedCode(group, this, *code);

    }

    dependencies_[i] = NULL;  // Zone-allocated, no need to delete.

  }

}

void CompilationInfo::RollbackDependencies() {

  // Unregister from all dependent maps if not yet committed.

  for (int i = 0; i < DependentCode::kGroupCount; i++) {

    ZoneList<Handle<HeapObject> >* group_objects = dependencies_[i];

    if (group_objects == NULL) continue;

    for (int j = 0; j < group_objects->length(); j++) {

      DependentCode::DependencyGroup group =

          static_cast<DependentCode::DependencyGroup>(i);

      DependentCode* dependent_code =

          DependentCode::ForObject(group_objects->at(j), group);

      dependent_code->RemoveCompilationInfo(group, this);

    }

    dependencies_[i] = NULL;  // Zone-allocated, no need to delete.

  }

}

int CompilationInfo::num_parameters() const {

  ASSERT(!IsStub());

  return scope()->num_parameters();

}

int CompilationInfo::num_heap_slots() const {

  if (IsStub()) {

    return 0;

  } else {

    return scope()->num_heap_slots();

  }

}

Code::Flags CompilationInfo::flags() const {

  if (IsStub()) {

    return Code::ComputeFlags(code_stub()->GetCodeKind(),

                              code_stub()->GetICState(),

                              code_stub()->GetExtraICState(),

                              code_stub()->GetStubType(),

                              code_stub()->GetStubFlags());

  } else {

    return Code::ComputeFlags(Code::OPTIMIZED_FUNCTION);

  }

}

// Disable optimization for the rest of the compilation pipeline.

void CompilationInfo::DisableOptimization() {

  bool is_optimizable_closure =

    FLAG_optimize_closures &&

    closure_.is_null() &&

    !scope_->HasTrivialOuterContext() &&

    !scope_->outer_scope_calls_non_strict_eval() &&

    !scope_->inside_with();

  SetMode(is_optimizable_closure ? BASE : NONOPT);

}

// Primitive functions are unlikely to be picked up by the stack-walking

// profiler, so they trigger their own optimization when they're called

// for the SharedFunctionInfo::kCallsUntilPrimitiveOptimization-th time.

bool CompilationInfo::ShouldSelfOptimize() {

  return FLAG_self_optimization &&

      FLAG_crankshaft &&

      !function()->flags()->Contains(kDontSelfOptimize) &&

      !function()->dont_optimize() &&

      function()->scope()->AllowsLazyCompilation() &&

      (shared_info().is_null() || !shared_info()->optimization_disabled());

}

// Determine whether to use the full compiler for all code. If the flag

// --always-full-compiler is specified this is the case. For the virtual frame

// based compiler the full compiler is also used if a debugger is connected, as

// the code from the full compiler supports mode precise break points. For the

// crankshaft adaptive compiler debugging the optimized code is not possible at

// all. However crankshaft support recompilation of functions, so in this case

// the full compiler need not be be used if a debugger is attached, but only if

// break points has actually been set.

static bool IsDebuggerActive(Isolate* isolate) {

#ifdef ENABLE_DEBUGGER_SUPPORT

  return isolate->use_crankshaft() ?

    isolate->debug()->has_break_points() :

    isolate->debugger()->IsDebuggerActive();

#else

  return false;

#endif

}

static bool AlwaysFullCompiler(Isolate* isolate) {

  return FLAG_always_full_compiler || IsDebuggerActive(isolate);

}

void RecompileJob::RecordOptimizationStats() {

  Handle<JSFunction> function = info()->closure();

  int opt_count = function->shared()->opt_count();

  function->shared()->set_opt_count(opt_count + 1);

  double ms_creategraph = time_taken_to_create_graph_.InMillisecondsF();

  double ms_optimize = time_taken_to_optimize_.InMillisecondsF();

  double ms_codegen = time_taken_to_codegen_.InMillisecondsF();

  if (FLAG_trace_opt) {

    PrintF("[optimizing ");

    function->ShortPrint();

    PrintF(" - took %0.3f, %0.3f, %0.3f ms]\n", ms_creategraph, ms_optimize,

           ms_codegen);

  }

  if (FLAG_trace_opt_stats) {

    static double compilation_time = 0.0;

    static int compiled_functions = 0;

    static int code_size = 0;

    compilation_time += (ms_creategraph + ms_optimize + ms_codegen);

    compiled_functions++;

    code_size += function->shared()->SourceSize();

    PrintF("Compiled: %d functions with %d byte source size in %fms.\n",

           compiled_functions,

           code_size,

           compilation_time);

  }

  if (FLAG_hydrogen_stats) {

    isolate()->GetHStatistics()->IncrementSubtotals(time_taken_to_create_graph_,

                                                    time_taken_to_optimize_,

                                                    time_taken_to_codegen_);

  }

}

// A return value of true indicates the compilation pipeline is still

// going, not necessarily that we optimized the code.

static bool MakeCrankshaftCode(CompilationInfo* info) {

  RecompileJob job(info);

  RecompileJob::Status status = job.CreateGraph();

  if (status != RecompileJob::SUCCEEDED) {

    return status != RecompileJob::FAILED;

  }

  status = job.OptimizeGraph();

  if (status != RecompileJob::SUCCEEDED) {

    status = job.AbortOptimization();

    return status != RecompileJob::FAILED;

  }

  status = job.GenerateAndInstallCode();

  return status != RecompileJob::FAILED;

}

class HOptimizedGraphBuilderWithPotisions: public HOptimizedGraphBuilder {

 public:

  explicit HOptimizedGraphBuilderWithPotisions(CompilationInfo* info)

      : HOptimizedGraphBuilder(info) {

  }

#define DEF_VISIT(type)                                 \

  virtual void Visit##type(type* node) V8_OVERRIDE {    \

    if (node->position() != RelocInfo::kNoPosition) {   \

      SetSourcePosition(node->position());              \

    }                                                   \

    HOptimizedGraphBuilder::Visit##type(node);          \

  }

  EXPRESSION_NODE_LIST(DEF_VISIT)

#undef DEF_VISIT

#define DEF_VISIT(type)                                          \

  virtual void Visit##type(type* node) V8_OVERRIDE {             \

    if (node->position() != RelocInfo::kNoPosition) {            \

      SetSourcePosition(node->position());                       \

    }                                                            \

    HOptimizedGraphBuilder::Visit##type(node);                   \

  }

  STATEMENT_NODE_LIST(DEF_VISIT)

#undef DEF_VISIT

#define DEF_VISIT(type)                                            \

  virtual void Visit##type(type* node) V8_OVERRIDE {               \

    HOptimizedGraphBuilder::Visit##type(node);                     \

  }

  MODULE_NODE_LIST(DEF_VISIT)

  DECLARATION_NODE_LIST(DEF_VISIT)

  AUXILIARY_NODE_LIST(DEF_VISIT)

#undef DEF_VISIT

};

RecompileJob::Status RecompileJob::CreateGraph() {

  ASSERT(isolate()->use_crankshaft());

  ASSERT(info()->IsOptimizing());

  ASSERT(!info()->IsCompilingForDebugging());

  // We should never arrive here if there is no code object on the

  // shared function object.

  ASSERT(info()->shared_info()->code()->kind() == Code::FUNCTION);

  // We should never arrive here if optimization has been disabled on the

  // shared function info.

  ASSERT(!info()->shared_info()->optimization_disabled());

  // Fall back to using the full code generator if it's not possible

  // to use the Hydrogen-based optimizing compiler. We already have

  // generated code for this from the shared function object.

  if (AlwaysFullCompiler(isolate())) {

    info()->AbortOptimization();

    return SetLastStatus(BAILED_OUT);

  }

  // Limit the number of times we re-compile a functions with

  // the optimizing compiler.

  const int kMaxOptCount =

      FLAG_deopt_every_n_times == 0 ? FLAG_max_opt_count : 1000;

  if (info()->opt_count() > kMaxOptCount) {

    info()->set_bailout_reason(kOptimizedTooManyTimes);

    return AbortOptimization();

  }

  // Due to an encoding limit on LUnallocated operands in the Lithium

  // language, we cannot optimize functions with too many formal parameters

  // or perform on-stack replacement for function with too many

  // stack-allocated local variables.

  //

  // The encoding is as a signed value, with parameters and receiver using

  // the negative indices and locals the non-negative ones.

  const int parameter_limit = -LUnallocated::kMinFixedSlotIndex;

  Scope* scope = info()->scope();

  if ((scope->num_parameters() + 1) > parameter_limit) {

    info()->set_bailout_reason(kTooManyParameters);

    return AbortOptimization();

  }

  const int locals_limit = LUnallocated::kMaxFixedSlotIndex;

  if (info()->is_osr() &&

      scope->num_parameters() + 1 + scope->num_stack_slots() > locals_limit) {

    info()->set_bailout_reason(kTooManyParametersLocals);

    return AbortOptimization();

  }

  // Take --hydrogen-filter into account.

  if (!info()->closure()->PassesFilter(FLAG_hydrogen_filter)) {

    info()->AbortOptimization();

    return SetLastStatus(BAILED_OUT);

  }

  // Recompile the unoptimized version of the code if the current version

  // doesn't have deoptimization support. Alternatively, we may decide to

  // run the full code generator to get a baseline for the compile-time

  // performance of the hydrogen-based compiler.

  bool should_recompile = !info()->shared_info()->has_deoptimization_support();

  if (should_recompile || FLAG_hydrogen_stats) {

    ElapsedTimer timer;

    if (FLAG_hydrogen_stats) {

      timer.Start();

    }

    CompilationInfoWithZone unoptimized(info()->shared_info());

    // Note that we use the same AST that we will use for generating the

    // optimized code.

    unoptimized.SetFunction(info()->function());

    unoptimized.SetScope(info()->scope());

    unoptimized.SetContext(info()->context());

    if (should_recompile) unoptimized.EnableDeoptimizationSupport();

    bool succeeded = FullCodeGenerator::MakeCode(&unoptimized);

    if (should_recompile) {

      if (!succeeded) return SetLastStatus(FAILED);

      Handle<SharedFunctionInfo> shared = info()->shared_info();

      shared->EnableDeoptimizationSupport(*unoptimized.code());

      // The existing unoptimized code was replaced with the new one.

      Compiler::RecordFunctionCompilation(

          Logger::LAZY_COMPILE_TAG, &unoptimized, shared);

    }

    if (FLAG_hydrogen_stats) {

      isolate()->GetHStatistics()->IncrementFullCodeGen(timer.Elapsed());

    }

  }

  // Check that the unoptimized, shared code is ready for

  // optimizations.  When using the always_opt flag we disregard the

  // optimizable marker in the code object and optimize anyway. This

  // is safe as long as the unoptimized code has deoptimization

  // support.

  ASSERT(FLAG_always_opt || info()->shared_info()->code()->optimizable());

  ASSERT(info()->shared_info()->has_deoptimization_support());

  if (FLAG_trace_hydrogen) {

    Handle<String> name = info()->function()->debug_name();

    PrintF("-----------------------------------------------------------\n");

    PrintF("Compiling method %s using hydrogen\n", *name->ToCString());

    isolate()->GetHTracer()->TraceCompilation(info());

  }

  // Type-check the function.

  AstTyper::Run(info());

  graph_builder_ = FLAG_emit_opt_code_positions

      ? new(info()->zone()) HOptimizedGraphBuilderWithPotisions(info())

      : new(info()->zone()) HOptimizedGraphBuilder(info());

  Timer t(this, &time_taken_to_create_graph_);

  graph_ = graph_builder_->CreateGraph();

  if (isolate()->has_pending_exception()) {

    info()->SetCode(Handle<Code>::null());

    return SetLastStatus(FAILED);

  }

  // The function being compiled may have bailed out due to an inline

  // candidate bailing out.  In such a case, we don't disable

  // optimization on the shared_info.

  ASSERT(!graph_builder_->inline_bailout() || graph_ == NULL);

  if (graph_ == NULL) {

    if (graph_builder_->inline_bailout()) {

      info_->AbortOptimization();

      return SetLastStatus(BAILED_OUT);

    } else {

      return AbortOptimization();

    }

  }

  if (info()->HasAbortedDueToDependencyChange()) {

    info_->set_bailout_reason(kBailedOutDueToDependencyChange);

    info_->AbortOptimization();

    return SetLastStatus(BAILED_OUT);

  }

  return SetLastStatus(SUCCEEDED);

}

RecompileJob::Status RecompileJob::OptimizeGraph() {

  DisallowHeapAllocation no_allocation;

  DisallowHandleAllocation no_handles;

  DisallowHandleDereference no_deref;

  DisallowCodeDependencyChange no_dependency_change;

  ASSERT(last_status() == SUCCEEDED);

  Timer t(this, &time_taken_to_optimize_);

  ASSERT(graph_ != NULL);

  BailoutReason bailout_reason = kNoReason;

  if (!graph_->Optimize(&bailout_reason)) {

    if (bailout_reason == kNoReason) graph_builder_->Bailout(bailout_reason);

    return SetLastStatus(BAILED_OUT);

  } else {

    chunk_ = LChunk::NewChunk(graph_);

    if (chunk_ == NULL) {

      return SetLastStatus(BAILED_OUT);

    }

  }

  return SetLastStatus(SUCCEEDED);

}

RecompileJob::Status RecompileJob::GenerateAndInstallCode() {

  ASSERT(last_status() == SUCCEEDED);

  ASSERT(!info()->HasAbortedDueToDependencyChange());

  DisallowCodeDependencyChange no_dependency_change;

  {  // Scope for timer.

    Timer timer(this, &time_taken_to_codegen_);

    ASSERT(chunk_ != NULL);

    ASSERT(graph_ != NULL);

    // Deferred handles reference objects that were accessible during

    // graph creation.  To make sure that we don't encounter inconsistencies

    // between graph creation and code generation, we disallow accessing

    // objects through deferred handles during the latter, with exceptions.

    DisallowDeferredHandleDereference no_deferred_handle_deref;

    Handle<Code> optimized_code = chunk_->Codegen();

    if (optimized_code.is_null()) {

      if (info()->bailout_reason() == kNoReason) {

        info()->set_bailout_reason(kCodeGenerationFailed);

      }

      return AbortOptimization();

    }

    info()->SetCode(optimized_code);

  }

  RecordOptimizationStats();

  // Add to the weak list of optimized code objects.

  info()->context()->native_context()->AddOptimizedCode(*info()->code());

  return SetLastStatus(SUCCEEDED);

}

static bool GenerateCode(CompilationInfo* info) {

  bool is_optimizing = info->isolate()->use_crankshaft() &&

                       !info->IsCompilingForDebugging() &&

                       info->IsOptimizing();

  if (is_optimizing) {

    Logger::TimerEventScope timer(

        info->isolate(), Logger::TimerEventScope::v8_recompile_synchronous);

    return MakeCrankshaftCode(info);

  } else {

    if (info->IsOptimizing()) {

      // Have the CompilationInfo decide if the compilation should be

      // BASE or NONOPT.

      info->DisableOptimization();

    }

    Logger::TimerEventScope timer(

        info->isolate(), Logger::TimerEventScope::v8_compile_full_code);

    return FullCodeGenerator::MakeCode(info);

  }

}

static bool MakeCode(CompilationInfo* info) {

  // Precondition: code has been parsed.  Postcondition: the code field in

  // the compilation info is set if compilation succeeded.

  ASSERT(info->function() != NULL);

  return Rewriter::Rewrite(info) && Scope::Analyze(info) && GenerateCode(info);

}

#ifdef ENABLE_DEBUGGER_SUPPORT

bool Compiler::MakeCodeForLiveEdit(CompilationInfo* info) {

  // Precondition: code has been parsed.  Postcondition: the code field in

  // the compilation info is set if compilation succeeded.

  bool succeeded = MakeCode(info);

  if (!info->shared_info().is_null()) {

    Handle<ScopeInfo> scope_info = ScopeInfo::Create(info->scope(),

                                                     info->zone());

    info->shared_info()->set_scope_info(*scope_info);

  }

  return succeeded;

}

#endif

static bool DebuggerWantsEagerCompilation(CompilationInfo* info,

                                          bool allow_lazy_without_ctx = false) {

  return LiveEditFunctionTracker::IsActive(info->isolate()) ||

         (info->isolate()->DebuggerHasBreakPoints() && !allow_lazy_without_ctx);

}

// Sets the expected number of properties based on estimate from compiler.

void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,

                                          int estimate) {

  // See the comment in SetExpectedNofProperties.

  if (shared->live_objects_may_exist()) return;

  // If no properties are added in the constructor, they are more likely

  // to be added later.

  if (estimate == 0) estimate = 2;

  // TODO(yangguo): check whether those heuristics are still up-to-date.

  // We do not shrink objects that go into a snapshot (yet), so we adjust

  // the estimate conservatively.

  if (Serializer::enabled()) {

    estimate += 2;

  } else if (FLAG_clever_optimizations) {

    // Inobject slack tracking will reclaim redundant inobject space later,

    // so we can afford to adjust the estimate generously.

    estimate += 8;

  } else {

    estimate += 3;

  }

  shared->set_expected_nof_properties(estimate);

}

static Handle<SharedFunctionInfo> MakeFunctionInfo(CompilationInfo* info) {

  Isolate* isolate = info->isolate();

  PostponeInterruptsScope postpone(isolate);

  ASSERT(!isolate->native_context().is_null());

  Handle<Script> script = info->script();

  // TODO(svenpanne) Obscure place for this, perhaps move to OnBeforeCompile?

  FixedArray* array = isolate->native_context()->embedder_data();

  script->set_context_data(array->get(0));

#ifdef ENABLE_DEBUGGER_SUPPORT

  if (info->is_eval()) {

    script->set_compilation_type(Script::COMPILATION_TYPE_EVAL);

    // For eval scripts add information on the function from which eval was

    // called.

    if (info->is_eval()) {

      StackTraceFrameIterator it(isolate);

      if (!it.done()) {

        script->set_eval_from_shared(it.frame()->function()->shared());

        Code* code = it.frame()->LookupCode();

        int offset = static_cast<int>(

            it.frame()->pc() - code->instruction_start());

        script->set_eval_from_instructions_offset(Smi::FromInt(offset));

      }

    }

  }

  // Notify debugger

  isolate->debugger()->OnBeforeCompile(script);

#endif

  // Only allow non-global compiles for eval.

  ASSERT(info->is_eval() || info->is_global());

  {

    Parser parser(info);

    if ((info->pre_parse_data() != NULL ||

         String::cast(script->source())->length() > FLAG_min_preparse_length) &&

        !DebuggerWantsEagerCompilation(info))

      parser.set_allow_lazy(true);

    if (!parser.Parse()) {

      return Handle<SharedFunctionInfo>::null();

    }

  }

  FunctionLiteral* lit = info->function();

  LiveEditFunctionTracker live_edit_tracker(isolate, lit);

  Handle<SharedFunctionInfo> result;

  {

    // Measure how long it takes to do the compilation; only take the

    // rest of the function into account to avoid overlap with the

    // parsing statistics.

    HistogramTimer* rate = info->is_eval()

          ? info->isolate()->counters()->compile_eval()

          : info->isolate()->counters()->compile();

    HistogramTimerScope timer(rate);

    // Compile the code.

    if (!MakeCode(info)) {

      if (!isolate->has_pending_exception()) isolate->StackOverflow();

      return Handle<SharedFunctionInfo>::null();

    }

    // Allocate function.

    ASSERT(!info->code().is_null());

    result =

        isolate->factory()->NewSharedFunctionInfo(

            lit->name(),

            lit->materialized_literal_count(),

            lit->is_generator(),

            info->code(),

            ScopeInfo::Create(info->scope(), info->zone()));

    ASSERT_EQ(RelocInfo::kNoPosition, lit->function_token_position());

    Compiler::SetFunctionInfo(result, lit, true, script);

    if (script->name()->IsString()) {

      PROFILE(isolate, CodeCreateEvent(

          info->is_eval()

          ? Logger::EVAL_TAG

              : Logger::ToNativeByScript(Logger::SCRIPT_TAG, *script),

                *info->code(),

                *result,

                info,

                String::cast(script->name())));

      GDBJIT(AddCode(Handle<String>(String::cast(script->name())),

                     script,

                     info->code(),

                     info));

    } else {

      PROFILE(isolate, CodeCreateEvent(

          info->is_eval()

          ? Logger::EVAL_TAG

              : Logger::ToNativeByScript(Logger::SCRIPT_TAG, *script),

                *info->code(),

                *result,

                info,

                isolate->heap()->empty_string()));

      GDBJIT(AddCode(Handle<String>(), script, info->code(), info));

    }

    // Hint to the runtime system used when allocating space for initial

    // property space by setting the expected number of properties for

    // the instances of the function.

    SetExpectedNofPropertiesFromEstimate(result,

                                         lit->expected_property_count());

    script->set_compilation_state(Script::COMPILATION_STATE_COMPILED);

  }

#ifdef ENABLE_DEBUGGER_SUPPORT

  // Notify debugger

  isolate->debugger()->OnAfterCompile(

      script, Debugger::NO_AFTER_COMPILE_FLAGS);

#endif

  live_edit_tracker.RecordFunctionInfo(result, lit, info->zone());

  return result;

}

Handle<SharedFunctionInfo> Compiler::Compile(Handle<String> source,

                                             Handle<Object> script_name,

                                             int line_offset,

                                             int column_offset,

                                             bool is_shared_cross_origin,

                                             Handle<Context> context,

                                             v8::Extension* extension,

                                             ScriptDataImpl* pre_data,

                                             Handle<Object> script_data,

                                             NativesFlag natives) {

  Isolate* isolate = source->GetIsolate();

  int source_length = source->length();

  isolate->counters()->total_load_size()->Increment(source_length);

  isolate->counters()->total_compile_size()->Increment(source_length);

  // The VM is in the COMPILER state until exiting this function.

  VMState<COMPILER> state(isolate);

  CompilationCache* compilation_cache = isolate->compilation_cache();

  // Do a lookup in the compilation cache but not for extensions.

  Handle<SharedFunctionInfo> result;

  if (extension == NULL) {

    result = compilation_cache->LookupScript(source,

                                             script_name,

                                             line_offset,

                                             column_offset,

                                             is_shared_cross_origin,

                                             context);

  }

  if (result.is_null()) {

    // No cache entry found. Do pre-parsing, if it makes sense, and compile

    // the script.

    // Building preparse data that is only used immediately after is only a

    // saving if we might skip building the AST for lazily compiled functions.

    // I.e., preparse data isn't relevant when the lazy flag is off, and

    // for small sources, odds are that there aren't many functions

    // that would be compiled lazily anyway, so we skip the preparse step

    // in that case too.

    // Create a script object describing the script to be compiled.

    Handle<Script> script = isolate->factory()->NewScript(source);

    if (natives == NATIVES_CODE) {

      script->set_type(Smi::FromInt(Script::TYPE_NATIVE));

    }

    if (!script_name.is_null()) {

      script->set_name(*script_name);

      script->set_line_offset(Smi::FromInt(line_offset));

      script->set_column_offset(Smi::FromInt(column_offset));

    }

    script->set_is_shared_cross_origin(is_shared_cross_origin);

    script->set_data(script_data.is_null() ? isolate->heap()->undefined_value()

                                           : *script_data);

    // Compile the function and add it to the cache.

    CompilationInfoWithZone info(script);

    info.MarkAsGlobal();

    info.SetExtension(extension);

    info.SetPreParseData(pre_data);

    info.SetContext(context);

    if (FLAG_use_strict) {

      info.SetLanguageMode(FLAG_harmony_scoping ? EXTENDED_MODE : STRICT_MODE);

    }

    result = MakeFunctionInfo(&info);

    if (extension == NULL && !result.is_null() && !result->dont_cache()) {

      compilation_cache->PutScript(source, context, result);

    }

  } else {

    if (result->ic_age() != isolate->heap()->global_ic_age()) {

      result->ResetForNewContext(isolate->heap()->global_ic_age());

    }

  }

  if (result.is_null()) isolate->ReportPendingMessages();

  return result;

}

Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,

                                                 Handle<Context> context,

                                                 bool is_global,

                                                 LanguageMode language_mode,

                                                 ParseRestriction restriction,

                                                 int scope_position) {

  Isolate* isolate = source->GetIsolate();

  int source_length = source->length();

  isolate->counters()->total_eval_size()->Increment(source_length);

  isolate->counters()->total_compile_size()->Increment(source_length);

  // The VM is in the COMPILER state until exiting this function.

  VMState<COMPILER> state(isolate);

  // Do a lookup in the compilation cache; if the entry is not there, invoke

  // the compiler and add the result to the cache.

  Handle<SharedFunctionInfo> result;

  CompilationCache* compilation_cache = isolate->compilation_cache();

  result = compilation_cache->LookupEval(source,

                                         context,

                                         is_global,

                                         language_mode,

                                         scope_position);

  if (result.is_null()) {

    // Create a script object describing the script to be compiled.

    Handle<Script> script = isolate->factory()->NewScript(source);

    CompilationInfoWithZone info(script);

    info.MarkAsEval();

    if (is_global) info.MarkAsGlobal();

    info.SetLanguageMode(language_mode);

    info.SetParseRestriction(restriction);

    info.SetContext(context);

    result = MakeFunctionInfo(&info);

    if (!result.is_null()) {

      // Explicitly disable optimization for eval code. We're not yet prepared

      // to handle eval-code in the optimizing compiler.

      result->DisableOptimization(kEval);

      // If caller is strict mode, the result must be in strict mode or

      // extended mode as well, but not the other way around. Consider:

      // eval("'use strict'; ...");

      ASSERT(language_mode != STRICT_MODE || !result->is_classic_mode());

      // If caller is in extended mode, the result must also be in

      // extended mode.

      ASSERT(language_mode != EXTENDED_MODE ||

             result->is_extended_mode());

      if (!result->dont_cache()) {

        compilation_cache->PutEval(

            source, context, is_global, result, scope_position);

      }

    }

  } else {

    if (result->ic_age() != isolate->heap()->global_ic_age()) {

      result->ResetForNewContext(isolate->heap()->global_ic_age());

    }

  }

  return result;

}

static bool InstallFullCode(CompilationInfo* info) {

  // Update the shared function info with the compiled code and the

  // scope info.  Please note, that the order of the shared function

  // info initialization is important since set_scope_info might

  // trigger a GC, causing the ASSERT below to be invalid if the code

  // was flushed. By setting the code object last we avoid this.

  Handle<SharedFunctionInfo> shared = info->shared_info();

  Handle<Code> code = info->code();

  CHECK(code->kind() == Code::FUNCTION);

  Handle<JSFunction> function = info->closure();

  Handle<ScopeInfo> scope_info =

      ScopeInfo::Create(info->scope(), info->zone());

  shared->set_scope_info(*scope_info);

  shared->ReplaceCode(*code);

  if (!function.is_null()) {

    function->ReplaceCode(*code);

    ASSERT(!function->IsOptimized());

  }

  // Set the expected number of properties for instances.

  FunctionLiteral* lit = info->function();

  int expected = lit->expected_property_count();

  SetExpectedNofPropertiesFromEstimate(shared, expected);

  // Check the function has compiled code.

  ASSERT(shared->is_compiled());

  shared->set_dont_optimize_reason(lit->dont_optimize_reason());

  shared->set_dont_inline(lit->flags()->Contains(kDontInline));

  shared->set_ast_node_count(lit->ast_node_count());

  if (info->isolate()->use_crankshaft() &&

      !function.is_null() &&

      !shared->optimization_disabled()) {

    // If we're asked to always optimize, we compile the optimized

    // version of the function right away - unless the debugger is

    // active as it makes no sense to compile optimized code then.

    if (FLAG_always_opt &&

        !info->isolate()->DebuggerHasBreakPoints()) {

      CompilationInfoWithZone optimized(function);

      optimized.SetOptimizing(BailoutId::None());

      return Compiler::CompileLazy(&optimized);

    }

  }

  return true;

}

static void InstallCodeCommon(CompilationInfo* info) {

  Handle<SharedFunctionInfo> shared = info->shared_info();

  Handle<Code> code = info->code();

  ASSERT(!code.is_null());

  // Set optimizable to false if this is disallowed by the shared

  // function info, e.g., we might have flushed the code and must

  // reset this bit when lazy compiling the code again.

  if (shared->optimization_disabled()) code->set_optimizable(false);

  if (shared->code() == *code) {

    // Do not send compilation event for the same code twice.

    return;

  }

  Compiler::RecordFunctionCompilation(Logger::LAZY_COMPILE_TAG, info, shared);

}

static void InsertCodeIntoOptimizedCodeMap(CompilationInfo* info) {

  Handle<Code> code = info->code();

  if (code->kind() != Code::OPTIMIZED_FUNCTION) return;  // Nothing to do.

  // Cache non-OSR optimized code.

  if (FLAG_cache_optimized_code && !info->is_osr()) {

    Handle<JSFunction> function = info->closure();

    Handle<SharedFunctionInfo> shared(function->shared());

    Handle<FixedArray> literals(function->literals());

    Handle<Context> native_context(function->context()->native_context());

    SharedFunctionInfo::AddToOptimizedCodeMap(

        shared, native_context, code, literals);

  }

}

static bool InstallCodeFromOptimizedCodeMap(CompilationInfo* info) {

  if (!info->IsOptimizing()) return false;  // Nothing to look up.

  // Lookup non-OSR optimized code.

  if (FLAG_cache_optimized_code && !info->is_osr()) {

    Handle<SharedFunctionInfo> shared = info->shared_info();

    Handle<JSFunction> function = info->closure();

    ASSERT(!function.is_null());

    Handle<Context> native_context(function->context()->native_context());

    int index = shared->SearchOptimizedCodeMap(*native_context);

    if (index > 0) {

      if (FLAG_trace_opt) {

        PrintF("[found optimized code for ");

        function->ShortPrint();

        PrintF("]\n");

      }

      // Caching of optimized code enabled and optimized code found.

      shared->InstallFromOptimizedCodeMap(*function, index);

      return true;

    }

  }

  return false;

}

bool Compiler::CompileLazy(CompilationInfo* info) {

  Isolate* isolate = info->isolate();

  // The VM is in the COMPILER state until exiting this function.

  VMState<COMPILER> state(isolate);

  PostponeInterruptsScope postpone(isolate);

  Handle<SharedFunctionInfo> shared = info->shared_info();

  int compiled_size = shared->end_position() - shared->start_position();

  isolate->counters()->total_compile_size()->Increment(compiled_size);

  if (InstallCodeFromOptimizedCodeMap(info)) return true;

  // Generate the AST for the lazily compiled function.

  if (Parser::Parse(info)) {

    // Measure how long it takes to do the lazy compilation; only take the

    // rest of the function into account to avoid overlap with the lazy

    // parsing statistics.

    HistogramTimerScope timer(isolate->counters()->compile_lazy());

    // After parsing we know the function's language mode. Remember it.

    LanguageMode language_mode = info->function()->language_mode();

    info->SetLanguageMode(language_mode);

    shared->set_language_mode(language_mode);

    // Compile the code.

    if (!MakeCode(info)) {

      if (!isolate->has_pending_exception()) {

        isolate->StackOverflow();

      }

    } else {

      InstallCodeCommon(info);

      if (info->IsOptimizing()) {

        // Optimized code successfully created.

        Handle<Code> code = info->code();

        ASSERT(shared->scope_info() != ScopeInfo::Empty(isolate));

        // TODO(titzer): Only replace the code if it was not an OSR compile.

        info->closure()->ReplaceCode(*code);

        InsertCodeIntoOptimizedCodeMap(info);

        return true;

      } else if (!info->is_osr()) {

        // Compilation failed. Replace with full code if not OSR compile.

        return InstallFullCode(info);

      }

    }

  }

  ASSERT(info->code().is_null());

  return false;

}

bool Compiler::RecompileConcurrent(Handle<JSFunction> closure,

                                   uint32_t osr_pc_offset) {

  bool compiling_for_osr = (osr_pc_offset != 0);

  Isolate* isolate = closure->GetIsolate();

  // Here we prepare compile data for the concurrent recompilation thread, but

  // this still happens synchronously and interrupts execution.

  Logger::TimerEventScope timer(

      isolate, Logger::TimerEventScope::v8_recompile_synchronous);

  if (!isolate->optimizing_compiler_thread()->IsQueueAvailable()) {

    if (FLAG_trace_concurrent_recompilation) {

      PrintF("  ** Compilation queue full, will retry optimizing ");

      closure->PrintName();

      PrintF(" on next run.\n");

    }

    return false;

  }

  SmartPointer<CompilationInfo> info(new CompilationInfoWithZone(closure));

  Handle<SharedFunctionInfo> shared = info->shared_info();

  if (compiling_for_osr) {

    BailoutId osr_ast_id =

        shared->code()->TranslatePcOffsetToAstId(osr_pc_offset);

    ASSERT(!osr_ast_id.IsNone());

    info->SetOptimizing(osr_ast_id);

    info->set_osr_pc_offset(osr_pc_offset);

    if (FLAG_trace_osr) {

      PrintF("[COSR - attempt to queue ");

      closure->PrintName();

      PrintF(" at AST id %d]\n", osr_ast_id.ToInt());

    }

  } else {

    info->SetOptimizing(BailoutId::None());

  }

  VMState<COMPILER> state(isolate);

  PostponeInterruptsScope postpone(isolate);

  int compiled_size = shared->end_position() - shared->start_position();

  isolate->counters()->total_compile_size()->Increment(compiled_size);

  {

    CompilationHandleScope handle_scope(*info);

    if (!compiling_for_osr && InstallCodeFromOptimizedCodeMap(*info)) {

      return true;

    }

    if (Parser::Parse(*info)) {

      LanguageMode language_mode = info->function()->language_mode();

      info->SetLanguageMode(language_mode);

      shared->set_language_mode(language_mode);

      info->SaveHandles();

      if (Rewriter::Rewrite(*info) && Scope::Analyze(*info)) {

        RecompileJob* job = new(info->zone()) RecompileJob(*info);

        RecompileJob::Status status = job->CreateGraph();

        if (status == RecompileJob::SUCCEEDED) {

          info.Detach();

          shared->code()->set_profiler_ticks(0);

          isolate->optimizing_compiler_thread()->QueueForOptimization(job);

          ASSERT(!isolate->has_pending_exception());

          return true;

        } else if (status == RecompileJob::BAILED_OUT) {

          isolate->clear_pending_exception();

          InstallFullCode(*info);

        }

      }

    }

  }

  if (isolate->has_pending_exception()) isolate->clear_pending_exception();

  return false;

}

Handle<Code> Compiler::InstallOptimizedCode(RecompileJob* job) {

  SmartPointer<CompilationInfo> info(job->info());

  // The function may have already been optimized by OSR.  Simply continue.

  // Except when OSR already disabled optimization for some reason.

  if (info->shared_info()->optimization_disabled()) {

    info->AbortOptimization();

    InstallFullCode(*info);

    if (FLAG_trace_concurrent_recompilation) {

      PrintF("  ** aborting optimization for ");

      info->closure()->PrintName();

      PrintF(" as it has been disabled.\n");

    }

    ASSERT(!info->closure()->IsInRecompileQueue());

    return Handle<Code>::null();

  }

  Isolate* isolate = info->isolate();

  VMState<COMPILER> state(isolate);

  Logger::TimerEventScope timer(

      isolate, Logger::TimerEventScope::v8_recompile_synchronous);

  // If crankshaft succeeded, install the optimized code else install

  // the unoptimized code.

  RecompileJob::Status status = job->last_status();

  if (info->HasAbortedDueToDependencyChange()) {

    info->set_bailout_reason(kBailedOutDueToDependencyChange);

    status = job->AbortOptimization();

  } else if (status != RecompileJob::SUCCEEDED) {

    info->set_bailout_reason(kFailedBailedOutLastTime);

    status = job->AbortOptimization();

  } else if (isolate->DebuggerHasBreakPoints()) {

    info->set_bailout_reason(kDebuggerIsActive);

    status = job->AbortOptimization();

  } else {

    status = job->GenerateAndInstallCode();

    ASSERT(status == RecompileJob::SUCCEEDED ||

           status == RecompileJob::BAILED_OUT);

  }

  InstallCodeCommon(*info);

  if (status == RecompileJob::SUCCEEDED) {

    Handle<Code> code = info->code();

    ASSERT(info->shared_info()->scope_info() != ScopeInfo::Empty(isolate));

    info->closure()->ReplaceCode(*code);

    if (info->shared_info()->SearchOptimizedCodeMap(

            info->closure()->context()->native_context()) == -1) {

      InsertCodeIntoOptimizedCodeMap(*info);

    }

    if (FLAG_trace_concurrent_recompilation) {

      PrintF("  ** Optimized code for ");

      info->closure()->PrintName();

      PrintF(" installed.\n");

    }

  } else {

    info->AbortOptimization();

    InstallFullCode(*info);

  }

  // Optimized code is finally replacing unoptimized code.  Reset the latter's

  // profiler ticks to prevent too soon re-opt after a deopt.

  info->shared_info()->code()->set_profiler_ticks(0);

  ASSERT(!info->closure()->IsInRecompileQueue());

  return (status == RecompileJob::SUCCEEDED) ? info->code()

                                             : Handle<Code>::null();

}

Handle<SharedFunctionInfo> Compiler::BuildFunctionInfo(FunctionLiteral* literal,

                                                       Handle<Script> script) {

  // Precondition: code has been parsed and scopes have been analyzed.

  CompilationInfoWithZone info(script);

  info.SetFunction(literal);

  info.SetScope(literal->scope());

  info.SetLanguageMode(literal->scope()->language_mode());

  Isolate* isolate = info.isolate();

  Factory* factory = isolate->factory();

  LiveEditFunctionTracker live_edit_tracker(isolate, literal);

  // Determine if the function can be lazily compiled. This is necessary to

  // allow some of our builtin JS files to be lazily compiled. These

  // builtins cannot be handled lazily by the parser, since we have to know

  // if a function uses the special natives syntax, which is something the

  // parser records.

  // If the debugger requests compilation for break points, we cannot be

  // aggressive about lazy compilation, because it might trigger compilation

  // of functions without an outer context when setting a breakpoint through

  // Debug::FindSharedFunctionInfoInScript.

  bool allow_lazy_without_ctx = literal->AllowsLazyCompilationWithoutContext();

  bool allow_lazy = literal->AllowsLazyCompilation() &&

      !DebuggerWantsEagerCompilation(&info, allow_lazy_without_ctx);

  Handle<ScopeInfo> scope_info(ScopeInfo::Empty(isolate));

  // Generate code

  if (FLAG_lazy && allow_lazy && !literal->is_parenthesized()) {

    Handle<Code> code = isolate->builtins()->LazyCompile();

    info.SetCode(code);

  } else if (GenerateCode(&info)) {

    ASSERT(!info.code().is_null());

    scope_info = ScopeInfo::Create(info.scope(), info.zone());

  } else {

    return Handle<SharedFunctionInfo>::null();

  }

  // Create a shared function info object.

  Handle<SharedFunctionInfo> result =

      factory->NewSharedFunctionInfo(literal->name(),

                                     literal->materialized_literal_count(),

                                     literal->is_generator(),

                                     info.code(),

                                     scope_info);

  SetFunctionInfo(result, literal, false, script);

  RecordFunctionCompilation(Logger::FUNCTION_TAG, &info, result);

  result->set_allows_lazy_compilation(allow_lazy);

  result->set_allows_lazy_compilation_without_context(allow_lazy_without_ctx);

  // Set the expected number of properties for instances and return

  // the resulting function.

  SetExpectedNofPropertiesFromEstimate(result,

                                       literal->expected_property_count());

  live_edit_tracker.RecordFunctionInfo(result, literal, info.zone());

  return result;

}

// Sets the function info on a function.

// The start_position points to the first '(' character after the function name

// in the full script source. When counting characters in the script source the

// the first character is number 0 (not 1).

void Compiler::SetFunctionInfo(Handle<SharedFunctionInfo> function_info,

                               FunctionLiteral* lit,

                               bool is_toplevel,

                               Handle<Script> script) {

  function_info->set_length(lit->parameter_count());

  function_info->set_formal_parameter_count(lit->parameter_count());

  function_info->set_script(*script);

  function_info->set_function_token_position(lit->function_token_position());

  function_info->set_start_position(lit->start_position());

  function_info->set_end_position(lit->end_position());

  function_info->set_is_expression(lit->is_expression());

  function_info->set_is_anonymous(lit->is_anonymous());

  function_info->set_is_toplevel(is_toplevel);

  function_info->set_inferred_name(*lit->inferred_name());

  function_info->set_allows_lazy_compilation(lit->AllowsLazyCompilation());

  function_info->set_allows_lazy_compilation_without_context(

      lit->AllowsLazyCompilationWithoutContext());

  function_info->set_language_mode(lit->language_mode());

  function_info->set_uses_arguments(lit->scope()->arguments() != NULL);

  function_info->set_has_duplicate_parameters(lit->has_duplicate_parameters());

  function_info->set_ast_node_count(lit->ast_node_count());

  function_info->set_is_function(lit->is_function());

  function_info->set_dont_optimize_reason(lit->dont_optimize_reason());

  function_info->set_dont_inline(lit->flags()->Contains(kDontInline));

  function_info->set_dont_cache(lit->flags()->Contains(kDontCache));

  function_info->set_is_generator(lit->is_generator());

}

void Compiler::RecordFunctionCompilation(Logger::LogEventsAndTags tag,

                                         CompilationInfo* info,

                                         Handle<SharedFunctionInfo> shared) {

  // SharedFunctionInfo is passed separately, because if CompilationInfo

  // was created using Script object, it will not have it.

  // Log the code generation. If source information is available include

  // script name and line number. Check explicitly whether logging is

  // enabled as finding the line number is not free.

  if (info->isolate()->logger()->is_logging_code_events() ||

      info->isolate()->cpu_profiler()->is_profiling()) {

    Handle<Script> script = info->script();

    Handle<Code> code = info->code();

    if (*code == info->isolate()->builtins()->builtin(Builtins::kLazyCompile))

      return;

    int line_num = GetScriptLineNumber(script, shared->start_position()) + 1;

    int column_num =

        GetScriptColumnNumber(script, shared->start_position()) + 1;

    USE(line_num);

    if (script->name()->IsString()) {

      PROFILE(info->isolate(),

              CodeCreateEvent(Logger::ToNativeByScript(tag, *script),

                              *code,

                              *shared,

                              info,

                              String::cast(script->name()),

                              line_num,

                              column_num));

    } else {

      PROFILE(info->isolate(),

              CodeCreateEvent(Logger::ToNativeByScript(tag, *script),

                              *code,

                              *shared,

                              info,

                              info->isolate()->heap()->empty_string(),

                              line_num,

                              column_num));

    }

  }

  GDBJIT(AddCode(Handle<String>(shared->DebugName()),

                 Handle<Script>(info->script()),

                 Handle<Code>(info->code()),

                 info));

}

CompilationPhase::CompilationPhase(const char* name, CompilationInfo* info)

    : name_(name), info_(info), zone_(info->isolate()) {

  if (FLAG_hydrogen_stats) {

    info_zone_start_allocation_size_ = info->zone()->allocation_size();

    timer_.Start();

  }

}

CompilationPhase::~CompilationPhase() {

  if (FLAG_hydrogen_stats) {

    unsigned size = zone()->allocation_size();

    size += info_->zone()->allocation_size() - info_zone_start_allocation_size_;

    isolate()->GetHStatistics()->SaveTiming(name_, timer_.Elapsed(), size);

  }

}

bool CompilationPhase::ShouldProduceTraceOutput() const {

  // Trace if the appropriate trace flag is set and the phase name's first

  // character is in the FLAG_trace_phase command line parameter.

  AllowHandleDereference allow_deref;

  bool tracing_on = info()->IsStub()

      ? FLAG_trace_hydrogen_stubs

      : (FLAG_trace_hydrogen &&

         info()->closure()->PassesFilter(FLAG_trace_hydrogen_filter));

  return (tracing_on &&

      OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);

}

} }  // namespace v8::internal