text: // 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 <stdarg.h>
  
  #include "v8.h"
  
  #include "bootstrapper.h"
  #include "code-stubs.h"
  #include "deoptimizer.h"
  #include "global-handles.h"
  #include "log.h"
  #include "macro-assembler.h"
  #include "platform.h"
  #include "runtime-profiler.h"
  #include "serialize.h"
  #include "string-stream.h"
  #include "vm-state-inl.h"
  
  namespace v8 {
  namespace internal {
  
  // The Profiler samples pc and sp values for the main thread.
  // Each sample is appended to a circular buffer.
  // An independent thread removes data and writes it to the log.
  // This design minimizes the time spent in the sampler.
  //
  class Profiler: public Thread {
   public:
    explicit Profiler(Isolate* isolate);
    void Engage();
    void Disengage();
  
    // Inserts collected profiling data into buffer.
    void Insert(TickSample* sample) {
      if (paused_)
        return;
  
      if (Succ(head_) == tail_) {
        overflow_ = true;
      } else {
        buffer_[head_] = *sample;
        head_ = Succ(head_);
        buffer_semaphore_->Signal();  // Tell we have an element.
      }
    }
  
    // Waits for a signal and removes profiling data.
    bool Remove(TickSample* sample) {
      buffer_semaphore_->Wait();  // Wait for an element.
      *sample = buffer_[tail_];
      bool result = overflow_;
      tail_ = Succ(tail_);
      overflow_ = false;
      return result;
    }
  
    void Run();
  
    // Pause and Resume TickSample data collection.
    bool paused() const { return paused_; }
    void pause() { paused_ = true; }
    void resume() { paused_ = false; }
  
   private:
    // Returns the next index in the cyclic buffer.
    int Succ(int index) { return (index + 1) % kBufferSize; }
  
    Isolate* isolate_;
    // Cyclic buffer for communicating profiling samples
    // between the signal handler and the worker thread.
    static const int kBufferSize = 128;
    TickSample buffer_[kBufferSize];  // Buffer storage.
    int head_;  // Index to the buffer head.
    int tail_;  // Index to the buffer tail.
    bool overflow_;  // Tell whether a buffer overflow has occurred.
    Semaphore* buffer_semaphore_;  // Sempahore used for buffer synchronization.
  
    // Tells whether profiler is engaged, that is, processing thread is stated.
    bool engaged_;
  
    // Tells whether worker thread should continue running.
    bool running_;
  
    // Tells whether we are currently recording tick samples.
    bool paused_;
  };
  
  
  //
  // Ticker used to provide ticks to the profiler and the sliding state
  // window.
  //
  class Ticker: public Sampler {
   public:
    Ticker(Isolate* isolate, int interval):
        Sampler(isolate, interval),
        profiler_(NULL) {}
  
    ~Ticker() { if (IsActive()) Stop(); }
  
    virtual void Tick(TickSample* sample) {
      if (profiler_) profiler_->Insert(sample);
    }
  
    void SetProfiler(Profiler* profiler) {
      ASSERT(profiler_ == NULL);
      profiler_ = profiler;
      IncreaseProfilingDepth();
      if (!FLAG_prof_lazy && !IsActive()) Start();
    }
  
    void ClearProfiler() {
      DecreaseProfilingDepth();
      profiler_ = NULL;
      if (IsActive()) Stop();
    }
  
   private:
    Profiler* profiler_;
  };
  
  
  //
  // Profiler implementation.
  //
  Profiler::Profiler(Isolate* isolate)
      : Thread("v8:Profiler"),
        isolate_(isolate),
        head_(0),
        tail_(0),
        overflow_(false),
        buffer_semaphore_(OS::CreateSemaphore(0)),
        engaged_(false),
        running_(false),
        paused_(false) {
  }
  
  
  void Profiler::Engage() {
    if (engaged_) return;
    engaged_ = true;
  
    OS::LogSharedLibraryAddresses();
  
    // Start thread processing the profiler buffer.
    running_ = true;
    Start();
  
    // Register to get ticks.
    Logger* logger = isolate_->logger();
    logger->ticker_->SetProfiler(this);
  
    logger->ProfilerBeginEvent();
  }
  
  
  void Profiler::Disengage() {
    if (!engaged_) return;
  
    // Stop receiving ticks.
    isolate_->logger()->ticker_->ClearProfiler();
  
    // Terminate the worker thread by setting running_ to false,
    // inserting a fake element in the queue and then wait for
    // the thread to terminate.
    running_ = false;
    TickSample sample;
    // Reset 'paused_' flag, otherwise semaphore may not be signalled.
    resume();
    Insert(&sample);
    Join();
  
    LOG(ISOLATE, UncheckedStringEvent("profiler", "end"));
  }
  
  
  void Profiler::Run() {
    TickSample sample;
    bool overflow = Remove(&sample);
    while (running_) {
      LOG(isolate_, TickEvent(&sample, overflow));
      overflow = Remove(&sample);
    }
  }
  
  
  // Low-level profiling event structures.
  
  struct LowLevelCodeCreateStruct {
    static const char kTag = 'C';
  
    int32_t name_size;
    Address code_address;
    int32_t code_size;
  };
  
  
  struct LowLevelCodeMoveStruct {
    static const char kTag = 'M';
  
    Address from_address;
    Address to_address;
  };
  
  
  struct LowLevelCodeDeleteStruct {
    static const char kTag = 'D';
  
    Address address;
  };
  
  
  struct LowLevelSnapshotPositionStruct {
    static const char kTag = 'P';
  
    Address address;
    int32_t position;
  };
  
  
  static const char kCodeMovingGCTag = 'G';
  
  
  //
  // Logger class implementation.
  //
  
  class Logger::NameMap {
   public:
    NameMap() : impl_(&PointerEquals) {}
  
    ~NameMap() {
      for (HashMap::Entry* p = impl_.Start(); p != NULL; p = impl_.Next(p)) {
        DeleteArray(static_cast<const char*>(p->value));
      }
    }
  
    void Insert(Address code_address, const char* name, int name_size) {
      HashMap::Entry* entry = FindOrCreateEntry(code_address);
      if (entry->value == NULL) {
        entry->value = CopyName(name, name_size);
      }
    }
  
    const char* Lookup(Address code_address) {
      HashMap::Entry* entry = FindEntry(code_address);
      return (entry != NULL) ? static_cast<const char*>(entry->value) : NULL;
    }
  
    void Remove(Address code_address) {
      HashMap::Entry* entry = FindEntry(code_address);
      if (entry != NULL) {
        DeleteArray(static_cast<char*>(entry->value));
        RemoveEntry(entry);
      }
    }
  
    void Move(Address from, Address to) {
      if (from == to) return;
      HashMap::Entry* from_entry = FindEntry(from);
      ASSERT(from_entry != NULL);
      void* value = from_entry->value;
      RemoveEntry(from_entry);
      HashMap::Entry* to_entry = FindOrCreateEntry(to);
      ASSERT(to_entry->value == NULL);
      to_entry->value = value;
    }
  
   private:
    static bool PointerEquals(void* lhs, void* rhs) {
      return lhs == rhs;
    }
  
    static char* CopyName(const char* name, int name_size) {
      char* result = NewArray<char>(name_size + 1);
      for (int i = 0; i < name_size; ++i) {
        char c = name[i];
        if (c == '\0') c = ' ';
        result[i] = c;
      }
      result[name_size] = '\0';
      return result;
    }
  
    HashMap::Entry* FindOrCreateEntry(Address code_address) {
      return impl_.Lookup(code_address, ComputePointerHash(code_address), true);
    }
  
    HashMap::Entry* FindEntry(Address code_address) {
      return impl_.Lookup(code_address, ComputePointerHash(code_address), false);
    }
  
    void RemoveEntry(HashMap::Entry* entry) {
      impl_.Remove(entry->key, entry->hash);
    }
  
    HashMap impl_;
  
    DISALLOW_COPY_AND_ASSIGN(NameMap);
  };
  
  
  class Logger::NameBuffer {
   public:
    NameBuffer() { Reset(); }
  
    void Reset() {
      utf8_pos_ = 0;
    }
  
    void AppendString(String* str) {
      if (str == NULL) return;
      int uc16_length = Min(str->length(), kUtf16BufferSize);
      String::WriteToFlat(str, utf16_buffer, 0, uc16_length);
      int previous = unibrow::Utf16::kNoPreviousCharacter;
      for (int i = 0; i < uc16_length && utf8_pos_ < kUtf8BufferSize; ++i) {
        uc16 c = utf16_buffer[i];
        if (c <= unibrow::Utf8::kMaxOneByteChar) {
          utf8_buffer_[utf8_pos_++] = static_cast<char>(c);
        } else {
          int char_length = unibrow::Utf8::Length(c, previous);
          if (utf8_pos_ + char_length > kUtf8BufferSize) break;
          unibrow::Utf8::Encode(utf8_buffer_ + utf8_pos_, c, previous);
          utf8_pos_ += char_length;
        }
        previous = c;
      }
    }
  
    void AppendBytes(const char* bytes, int size) {
      size = Min(size, kUtf8BufferSize - utf8_pos_);
      OS::MemCopy(utf8_buffer_ + utf8_pos_, bytes, size);
      utf8_pos_ += size;
    }
  
    void AppendBytes(const char* bytes) {
      AppendBytes(bytes, StrLength(bytes));
    }
  
    void AppendByte(char c) {
      if (utf8_pos_ >= kUtf8BufferSize) return;
      utf8_buffer_[utf8_pos_++] = c;
    }
  
    void AppendInt(int n) {
      Vector<char> buffer(utf8_buffer_ + utf8_pos_, kUtf8BufferSize - utf8_pos_);
      int size = OS::SNPrintF(buffer, "%d", n);
      if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
        utf8_pos_ += size;
      }
    }
  
    void AppendHex(uint32_t n) {
      Vector<char> buffer(utf8_buffer_ + utf8_pos_, kUtf8BufferSize - utf8_pos_);
      int size = OS::SNPrintF(buffer, "%x", n);
      if (size > 0 && utf8_pos_ + size <= kUtf8BufferSize) {
        utf8_pos_ += size;
      }
    }
  
    const char* get() { return utf8_buffer_; }
    int size() const { return utf8_pos_; }
  
   private:
    static const int kUtf8BufferSize = 512;
    static const int kUtf16BufferSize = 128;
  
    int utf8_pos_;
    char utf8_buffer_[kUtf8BufferSize];
    uc16 utf16_buffer[kUtf16BufferSize];
  };
  
  
  Logger::Logger(Isolate* isolate)
    : isolate_(isolate),
      ticker_(NULL),
      profiler_(NULL),
      log_events_(NULL),
      logging_nesting_(0),
      cpu_profiler_nesting_(0),
      log_(new Log(this)),
      name_buffer_(new NameBuffer),
      address_to_name_map_(NULL),
      is_initialized_(false),
      code_event_handler_(NULL),
      last_address_(NULL),
      prev_sp_(NULL),
      prev_function_(NULL),
      prev_to_(NULL),
      prev_code_(NULL),
      epoch_(0) {
  }
  
  
  Logger::~Logger() {
    delete address_to_name_map_;
    delete name_buffer_;
    delete log_;
  }
  
  
  void Logger::IssueCodeAddedEvent(Code* code,
                                   Script* script,
                                   const char* name,
                                   size_t name_len) {
    JitCodeEvent event;
    memset(&event, 0, sizeof(event));
    event.type = JitCodeEvent::CODE_ADDED;
    event.code_start = code->instruction_start();
    event.code_len = code->instruction_size();
    Handle<Script> script_handle =
        script != NULL ? Handle<Script>(script) : Handle<Script>();
    event.script = ToApiHandle<v8::Script>(script_handle);
    event.name.str = name;
    event.name.len = name_len;
  
    code_event_handler_(&event);
  }
  
  
  void Logger::IssueCodeMovedEvent(Address from, Address to) {
    Code* from_code = Code::cast(HeapObject::FromAddress(from));
  
    JitCodeEvent event;
    event.type = JitCodeEvent::CODE_MOVED;
    event.code_start = from_code->instruction_start();
    event.code_len = from_code->instruction_size();
  
    // Calculate the header size.
    const size_t header_size =
        from_code->instruction_start() - reinterpret_cast<byte*>(from_code);
  
    // Calculate the new start address of the instructions.
    event.new_code_start =
        reinterpret_cast<byte*>(HeapObject::FromAddress(to)) + header_size;
  
    code_event_handler_(&event);
  }
  
  
  void Logger::IssueCodeRemovedEvent(Address from) {
    Code* from_code = Code::cast(HeapObject::FromAddress(from));
  
    JitCodeEvent event;
    event.type = JitCodeEvent::CODE_REMOVED;
    event.code_start = from_code->instruction_start();
    event.code_len = from_code->instruction_size();
  
    code_event_handler_(&event);
  }
  
  void Logger::IssueAddCodeLinePosInfoEvent(
      void* jit_handler_data,
      int pc_offset,
      int position,
      JitCodeEvent::PositionType position_type) {
    JitCodeEvent event;
    memset(&event, 0, sizeof(event));
    event.type = JitCodeEvent::CODE_ADD_LINE_POS_INFO;
    event.user_data = jit_handler_data;
    event.line_info.offset = pc_offset;
    event.line_info.pos = position;
    event.line_info.position_type = position_type;
  
    code_event_handler_(&event);
  }
  
  void* Logger::IssueStartCodePosInfoEvent() {
    JitCodeEvent event;
    memset(&event, 0, sizeof(event));
    event.type = JitCodeEvent::CODE_START_LINE_INFO_RECORDING;
  
    code_event_handler_(&event);
    return event.user_data;
  }
  
  void Logger::IssueEndCodePosInfoEvent(Code* code, void* jit_handler_data) {
    JitCodeEvent event;
    memset(&event, 0, sizeof(event));
    event.type = JitCodeEvent::CODE_END_LINE_INFO_RECORDING;
    event.code_start = code->instruction_start();
    event.user_data = jit_handler_data;
  
    code_event_handler_(&event);
  }
  
  #define DECLARE_EVENT(ignore1, name) name,
  static const char* const kLogEventsNames[Logger::NUMBER_OF_LOG_EVENTS] = {
    LOG_EVENTS_AND_TAGS_LIST(DECLARE_EVENT)
  };
  #undef DECLARE_EVENT
  
  
  void Logger::ProfilerBeginEvent() {
    if (!log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    msg.Append("profiler,\"begin\",%d\n", kSamplingIntervalMs);
    msg.WriteToLogFile();
  }
  
  
  void Logger::StringEvent(const char* name, const char* value) {
    if (FLAG_log) UncheckedStringEvent(name, value);
  }
  
  
  void Logger::UncheckedStringEvent(const char* name, const char* value) {
    if (!log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,\"%s\"\n", name, value);
    msg.WriteToLogFile();
  }
  
  
  void Logger::IntEvent(const char* name, int value) {
    if (FLAG_log) UncheckedIntEvent(name, value);
  }
  
  
  void Logger::IntPtrTEvent(const char* name, intptr_t value) {
    if (FLAG_log) UncheckedIntPtrTEvent(name, value);
  }
  
  
  void Logger::UncheckedIntEvent(const char* name, int value) {
    if (!log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,%d\n", name, value);
    msg.WriteToLogFile();
  }
  
  
  void Logger::UncheckedIntPtrTEvent(const char* name, intptr_t value) {
    if (!log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,%" V8_PTR_PREFIX "d\n", name, value);
    msg.WriteToLogFile();
  }
  
  
  void Logger::HandleEvent(const char* name, Object** location) {
    if (!log_->IsEnabled() || !FLAG_log_handles) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,0x%" V8PRIxPTR "\n", name, location);
    msg.WriteToLogFile();
  }
  
  
  // ApiEvent is private so all the calls come from the Logger class.  It is the
  // caller's responsibility to ensure that log is enabled and that
  // FLAG_log_api is true.
  void Logger::ApiEvent(const char* format, ...) {
    ASSERT(log_->IsEnabled() && FLAG_log_api);
    LogMessageBuilder msg(this);
    va_list ap;
    va_start(ap, format);
    msg.AppendVA(format, ap);
    va_end(ap);
    msg.WriteToLogFile();
  }
  
  
  void Logger::ApiNamedSecurityCheck(Object* key) {
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    if (key->IsString()) {
      SmartArrayPointer<char> str =
          String::cast(key)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
      ApiEvent("api,check-security,\"%s\"\n", *str);
    } else if (key->IsSymbol()) {
      Symbol* symbol = Symbol::cast(key);
      if (symbol->name()->IsUndefined()) {
        ApiEvent("api,check-security,symbol(hash %x)\n",
                 Symbol::cast(key)->Hash());
      } else {
        SmartArrayPointer<char> str = String::cast(symbol->name())->ToCString(
            DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
        ApiEvent("api,check-security,symbol(\"%s\" hash %x)\n",
                 *str,
                 Symbol::cast(key)->Hash());
      }
    } else if (key->IsUndefined()) {
      ApiEvent("api,check-security,undefined\n");
    } else {
      ApiEvent("api,check-security,['no-name']\n");
    }
  }
  
  
  void Logger::SharedLibraryEvent(const char* library_path,
                                  uintptr_t start,
                                  uintptr_t end) {
    if (!log_->IsEnabled() || !FLAG_prof) return;
    LogMessageBuilder msg(this);
    msg.Append("shared-library,\"%s\",0x%08" V8PRIxPTR ",0x%08" V8PRIxPTR "\n",
               library_path,
               start,
               end);
    msg.WriteToLogFile();
  }
  
  
  void Logger::SharedLibraryEvent(const wchar_t* library_path,
                                  uintptr_t start,
                                  uintptr_t end) {
    if (!log_->IsEnabled() || !FLAG_prof) return;
    LogMessageBuilder msg(this);
    msg.Append("shared-library,\"%ls\",0x%08" V8PRIxPTR ",0x%08" V8PRIxPTR "\n",
               library_path,
               start,
               end);
    msg.WriteToLogFile();
  }
  
  
  void Logger::TimerEvent(StartEnd se, const char* name) {
    if (!log_->IsEnabled()) return;
    ASSERT(FLAG_log_internal_timer_events);
    LogMessageBuilder msg(this);
    int since_epoch = static_cast<int>(OS::Ticks() - epoch_);
    const char* format = (se == START) ? "timer-event-start,\"%s\",%ld\n"
                                       : "timer-event-end,\"%s\",%ld\n";
    msg.Append(format, name, since_epoch);
    msg.WriteToLogFile();
  }
  
  
  void Logger::EnterExternal(Isolate* isolate) {
    LOG(isolate, TimerEvent(START, TimerEventScope::v8_external));
    ASSERT(isolate->current_vm_state() == JS);
    isolate->set_current_vm_state(EXTERNAL);
  }
  
  
  void Logger::LeaveExternal(Isolate* isolate) {
    LOG(isolate, TimerEvent(END, TimerEventScope::v8_external));
    ASSERT(isolate->current_vm_state() == EXTERNAL);
    isolate->set_current_vm_state(JS);
  }
  
  
  void Logger::TimerEventScope::LogTimerEvent(StartEnd se) {
    LOG(isolate_, TimerEvent(se, name_));
  }
  
  
  const char* Logger::TimerEventScope::v8_recompile_synchronous =
      "V8.RecompileSynchronous";
  const char* Logger::TimerEventScope::v8_recompile_parallel =
      "V8.RecompileParallel";
  const char* Logger::TimerEventScope::v8_compile_full_code =
      "V8.CompileFullCode";
  const char* Logger::TimerEventScope::v8_execute = "V8.Execute";
  const char* Logger::TimerEventScope::v8_external = "V8.External";
  
  
  void Logger::LogRegExpSource(Handle<JSRegExp> regexp) {
    // Prints "/" + re.source + "/" +
    //      (re.global?"g":"") + (re.ignorecase?"i":"") + (re.multiline?"m":"")
    LogMessageBuilder msg(this);
  
    Handle<Object> source = GetProperty(regexp, "source");
    if (!source->IsString()) {
      msg.Append("no source");
      return;
    }
  
    switch (regexp->TypeTag()) {
      case JSRegExp::ATOM:
        msg.Append('a');
        break;
      default:
        break;
    }
    msg.Append('/');
    msg.AppendDetailed(*Handle<String>::cast(source), false);
    msg.Append('/');
  
    // global flag
    Handle<Object> global = GetProperty(regexp, "global");
    if (global->IsTrue()) {
      msg.Append('g');
    }
    // ignorecase flag
    Handle<Object> ignorecase = GetProperty(regexp, "ignoreCase");
    if (ignorecase->IsTrue()) {
      msg.Append('i');
    }
    // multiline flag
    Handle<Object> multiline = GetProperty(regexp, "multiline");
    if (multiline->IsTrue()) {
      msg.Append('m');
    }
  
    msg.WriteToLogFile();
  }
  
  
  void Logger::RegExpCompileEvent(Handle<JSRegExp> regexp, bool in_cache) {
    if (!log_->IsEnabled() || !FLAG_log_regexp) return;
    LogMessageBuilder msg(this);
    msg.Append("regexp-compile,");
    LogRegExpSource(regexp);
    msg.Append(in_cache ? ",hit\n" : ",miss\n");
    msg.WriteToLogFile();
  }
  
  
  void Logger::LogRuntime(Vector<const char> format,
                          JSArray* args) {
    if (!log_->IsEnabled() || !FLAG_log_runtime) return;
    HandleScope scope(isolate_);
    LogMessageBuilder msg(this);
    for (int i = 0; i < format.length(); i++) {
      char c = format[i];
      if (c == '%' && i <= format.length() - 2) {
        i++;
        ASSERT('0' <= format[i] && format[i] <= '9');
        MaybeObject* maybe = args->GetElement(format[i] - '0');
        Object* obj;
        if (!maybe->ToObject(&obj)) {
          msg.Append("<exception>");
          continue;
        }
        i++;
        switch (format[i]) {
          case 's':
            msg.AppendDetailed(String::cast(obj), false);
            break;
          case 'S':
            msg.AppendDetailed(String::cast(obj), true);
            break;
          case 'r':
            Logger::LogRegExpSource(Handle<JSRegExp>(JSRegExp::cast(obj)));
            break;
          case 'x':
            msg.Append("0x%x", Smi::cast(obj)->value());
            break;
          case 'i':
            msg.Append("%i", Smi::cast(obj)->value());
            break;
          default:
            UNREACHABLE();
        }
      } else {
        msg.Append(c);
      }
    }
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::ApiIndexedSecurityCheck(uint32_t index) {
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    ApiEvent("api,check-security,%u\n", index);
  }
  
  
  void Logger::ApiNamedPropertyAccess(const char* tag,
                                      JSObject* holder,
                                      Object* name) {
    ASSERT(name->IsName());
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    String* class_name_obj = holder->class_name();
    SmartArrayPointer<char> class_name =
        class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
    if (name->IsString()) {
      SmartArrayPointer<char> property_name =
          String::cast(name)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
      ApiEvent("api,%s,\"%s\",\"%s\"\n", tag, *class_name, *property_name);
    } else {
      Symbol* symbol = Symbol::cast(name);
      uint32_t hash = symbol->Hash();
      if (symbol->name()->IsUndefined()) {
        ApiEvent("api,%s,\"%s\",symbol(hash %x)\n", tag, *class_name, hash);
      } else {
        SmartArrayPointer<char> str = String::cast(symbol->name())->ToCString(
            DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
        ApiEvent("api,%s,\"%s\",symbol(\"%s\" hash %x)\n",
                 tag, *class_name, *str, hash);
      }
    }
  }
  
  void Logger::ApiIndexedPropertyAccess(const char* tag,
                                        JSObject* holder,
                                        uint32_t index) {
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    String* class_name_obj = holder->class_name();
    SmartArrayPointer<char> class_name =
        class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
    ApiEvent("api,%s,\"%s\",%u\n", tag, *class_name, index);
  }
  
  void Logger::ApiObjectAccess(const char* tag, JSObject* object) {
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    String* class_name_obj = object->class_name();
    SmartArrayPointer<char> class_name =
        class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
    ApiEvent("api,%s,\"%s\"\n", tag, *class_name);
  }
  
  
  void Logger::ApiEntryCall(const char* name) {
    if (!log_->IsEnabled() || !FLAG_log_api) return;
    ApiEvent("api,%s\n", name);
  }
  
  
  void Logger::NewEvent(const char* name, void* object, size_t size) {
    if (!log_->IsEnabled() || !FLAG_log) return;
    LogMessageBuilder msg(this);
    msg.Append("new,%s,0x%" V8PRIxPTR ",%u\n", name, object,
               static_cast<unsigned int>(size));
    msg.WriteToLogFile();
  }
  
  
  void Logger::DeleteEvent(const char* name, void* object) {
    if (!log_->IsEnabled() || !FLAG_log) return;
    LogMessageBuilder msg(this);
    msg.Append("delete,%s,0x%" V8PRIxPTR "\n", name, object);
    msg.WriteToLogFile();
  }
  
  
  void Logger::NewEventStatic(const char* name, void* object, size_t size) {
    Isolate::Current()->logger()->NewEvent(name, object, size);
  }
  
  
  void Logger::DeleteEventStatic(const char* name, void* object) {
    Isolate::Current()->logger()->DeleteEvent(name, object);
  }
  
  void Logger::CallbackEventInternal(const char* prefix, Name* name,
                                     Address entry_point) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,%s,-2,",
               kLogEventsNames[CODE_CREATION_EVENT],
               kLogEventsNames[CALLBACK_TAG]);
    msg.AppendAddress(entry_point);
    if (name->IsString()) {
      SmartArrayPointer<char> str =
          String::cast(name)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
      msg.Append(",1,\"%s%s\"", prefix, *str);
    } else {
      Symbol* symbol = Symbol::cast(name);
      if (symbol->name()->IsUndefined()) {
        msg.Append(",1,symbol(hash %x)", prefix, symbol->Hash());
      } else {
        SmartArrayPointer<char> str = String::cast(symbol->name())->ToCString(
            DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
        msg.Append(",1,symbol(\"%s\" hash %x)", prefix, *str, symbol->Hash());
      }
    }
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::CallbackEvent(Name* name, Address entry_point) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    CallbackEventInternal("", name, entry_point);
  }
  
  
  void Logger::GetterCallbackEvent(Name* name, Address entry_point) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    CallbackEventInternal("get ", name, entry_point);
  }
  
  
  void Logger::SetterCallbackEvent(Name* name, Address entry_point) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    CallbackEventInternal("set ", name, entry_point);
  }
  
  
  void Logger::AppendName(Name* name) {
    if (name->IsString()) {
      name_buffer_->AppendString(String::cast(name));
    } else {
      Symbol* symbol = Symbol::cast(name);
      name_buffer_->AppendBytes("symbol(");
      if (!symbol->name()->IsUndefined()) {
        name_buffer_->AppendBytes("\"");
        name_buffer_->AppendString(String::cast(symbol->name()));
        name_buffer_->AppendBytes("\" ");
      }
      name_buffer_->AppendBytes("hash ");
      name_buffer_->AppendHex(symbol->Hash());
      name_buffer_->AppendByte(')');
    }
  }
  
  
  void Logger::InitNameBuffer(LogEventsAndTags tag) {
      name_buffer_->Reset();
      name_buffer_->AppendBytes(kLogEventsNames[tag]);
      name_buffer_->AppendByte(':');
  }
  
  
  void Logger::LogRecordedBuffer(Code* code, SharedFunctionInfo* shared) {
    if (code_event_handler_ != NULL) {
      Script* script = shared && shared->script()->IsScript() ?
          Script::cast(shared->script()) : NULL;
      IssueCodeAddedEvent(code,
                          script,
                          name_buffer_->get(),
                          name_buffer_->size());
    }
    if (!log_->IsEnabled()) return;
    if (FLAG_ll_prof) {
      LowLevelCodeCreateEvent(code, name_buffer_->get(), name_buffer_->size());
    }
    if (Serializer::enabled()) {
      RegisterSnapshotCodeName(code, name_buffer_->get(), name_buffer_->size());
    }
  }
  
  
  void Logger::AppendCodeCreateHeader(LogMessageBuilder* msg,
                                      LogEventsAndTags tag,
                                      Code* code) {
    ASSERT(msg);
    msg->Append("%s,%s,%d,",
                kLogEventsNames[CODE_CREATION_EVENT],
                kLogEventsNames[tag],
                code->kind());
    msg->AppendAddress(code->address());
    msg->Append(",%d,", code->ExecutableSize());
  }
  
  
  void Logger::AppendSymbolName(LogMessageBuilder* msg,
                                Symbol* symbol) {
      ASSERT(symbol);
      msg->Append("symbol(");
      if (!symbol->name()->IsUndefined()) {
        msg->Append("\"");
        msg->AppendDetailed(String::cast(symbol->name()), false);
        msg->Append("\" ");
      }
      msg->Append("hash %x)", symbol->Hash());
  }
  
  
  void Logger::CodeCreateEvent(LogEventsAndTags tag,
                               Code* code,
                               const char* comment) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(tag);
      name_buffer_->AppendBytes(comment);
      LogRecordedBuffer(code, NULL);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, tag, code);
    msg.AppendDoubleQuotedString(comment);
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::CodeCreateEvent(LogEventsAndTags tag,
                               Code* code,
                               Name* name) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(tag);
      AppendName(name);
      LogRecordedBuffer(code, NULL);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, tag, code);
    if (name->IsString()) {
      msg.Append('"');
      msg.AppendDetailed(String::cast(name), false);
      msg.Append('"');
    } else {
      AppendSymbolName(&msg, Symbol::cast(name));
    }
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  // ComputeMarker must only be used when SharedFunctionInfo is known.
  static const char* ComputeMarker(Code* code) {
    switch (code->kind()) {
      case Code::FUNCTION: return code->optimizable() ? "~" : "";
      case Code::OPTIMIZED_FUNCTION: return "*";
      default: return "";
    }
  }
  
  
  void Logger::CodeCreateEvent(LogEventsAndTags tag,
                               Code* code,
                               SharedFunctionInfo* shared,
                               CompilationInfo* info,
                               Name* name) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(tag);
      name_buffer_->AppendBytes(ComputeMarker(code));
      AppendName(name);
      LogRecordedBuffer(code, shared);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    if (code == Isolate::Current()->builtins()->builtin(
        Builtins::kLazyCompile))
      return;
  
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, tag, code);
    if (name->IsString()) {
      SmartArrayPointer<char> str =
          String::cast(name)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
      msg.Append("\"%s\"", *str);
    } else {
      AppendSymbolName(&msg, Symbol::cast(name));
    }
    msg.Append(',');
    msg.AppendAddress(shared->address());
    msg.Append(",%s", ComputeMarker(code));
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  // Although, it is possible to extract source and line from
  // the SharedFunctionInfo object, we left it to caller
  // to leave logging functions free from heap allocations.
  void Logger::CodeCreateEvent(LogEventsAndTags tag,
                               Code* code,
                               SharedFunctionInfo* shared,
                               CompilationInfo* info,
                               Name* source, int line) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(tag);
      name_buffer_->AppendBytes(ComputeMarker(code));
      name_buffer_->AppendString(shared->DebugName());
      name_buffer_->AppendByte(' ');
      if (source->IsString()) {
        name_buffer_->AppendString(String::cast(source));
      } else {
        name_buffer_->AppendBytes("symbol(hash ");
        name_buffer_->AppendHex(Name::cast(source)->Hash());
        name_buffer_->AppendByte(')');
      }
      name_buffer_->AppendByte(':');
      name_buffer_->AppendInt(line);
      LogRecordedBuffer(code, shared);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, tag, code);
    SmartArrayPointer<char> name =
        shared->DebugName()->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
    msg.Append("\"%s ", *name);
    if (source->IsString()) {
      SmartArrayPointer<char> sourcestr =
         String::cast(source)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
      msg.Append("%s", *sourcestr);
    } else {
      AppendSymbolName(&msg, Symbol::cast(source));
    }
    msg.Append(":%d\",", line);
    msg.AppendAddress(shared->address());
    msg.Append(",%s", ComputeMarker(code));
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::CodeCreateEvent(LogEventsAndTags tag, Code* code, int args_count) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(tag);
      name_buffer_->AppendInt(args_count);
      LogRecordedBuffer(code, NULL);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, tag, code);
    msg.Append("\"args_count: %d\"", args_count);
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::CodeMovingGCEvent() {
    if (!log_->IsEnabled() || !FLAG_ll_prof) return;
    LowLevelLogWriteBytes(&kCodeMovingGCTag, sizeof(kCodeMovingGCTag));
    OS::SignalCodeMovingGC();
  }
  
  
  void Logger::RegExpCodeCreateEvent(Code* code, String* source) {
    if (!is_logging_code_events()) return;
    if (FLAG_ll_prof || Serializer::enabled() || code_event_handler_ != NULL) {
      InitNameBuffer(REG_EXP_TAG);
      name_buffer_->AppendString(source);
      LogRecordedBuffer(code, NULL);
    }
  
    if (!FLAG_log_code || !log_->IsEnabled()) return;
    LogMessageBuilder msg(this);
    AppendCodeCreateHeader(&msg, REG_EXP_TAG, code);
    msg.Append('"');
    msg.AppendDetailed(source, false);
    msg.Append('"');
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::CodeMoveEvent(Address from, Address to) {
    if (code_event_handler_ != NULL) IssueCodeMovedEvent(from, to);
    if (!log_->IsEnabled()) return;
    if (FLAG_ll_prof) LowLevelCodeMoveEvent(from, to);
    if (Serializer::enabled() && address_to_name_map_ != NULL) {
      address_to_name_map_->Move(from, to);
    }
    MoveEventInternal(CODE_MOVE_EVENT, from, to);
  }
  
  
  void Logger::CodeDeleteEvent(Address from) {
    if (code_event_handler_ != NULL) IssueCodeRemovedEvent(from);
    if (!log_->IsEnabled()) return;
    if (FLAG_ll_prof) LowLevelCodeDeleteEvent(from);
    if (Serializer::enabled() && address_to_name_map_ != NULL) {
      address_to_name_map_->Remove(from);
    }
    DeleteEventInternal(CODE_DELETE_EVENT, from);
  }
  
  void Logger::CodeLinePosInfoAddPositionEvent(void* jit_handler_data,
                                       int pc_offset,
                                       int position) {
    if (code_event_handler_ != NULL) {
      IssueAddCodeLinePosInfoEvent(jit_handler_data,
                                   pc_offset,
                                   position,
                                   JitCodeEvent::POSITION);
    }
  }
  
  void Logger::CodeLinePosInfoAddStatementPositionEvent(void* jit_handler_data,
                                                        int pc_offset,
                                                        int position) {
    if (code_event_handler_ != NULL) {
      IssueAddCodeLinePosInfoEvent(jit_handler_data,
                                   pc_offset,
                                   position,
                                   JitCodeEvent::STATEMENT_POSITION);
    }
  }
  
  void Logger::CodeStartLinePosInfoRecordEvent(PositionsRecorder* pos_recorder) {
    if (code_event_handler_ != NULL) {
        pos_recorder->AttachJITHandlerData(IssueStartCodePosInfoEvent());
    }
  }
  
  void Logger::CodeEndLinePosInfoRecordEvent(Code* code,
                                             void* jit_handler_data) {
    if (code_event_handler_ != NULL) {
      IssueEndCodePosInfoEvent(code, jit_handler_data);
    }
  }
  
  void Logger::SnapshotPositionEvent(Address addr, int pos) {
    if (!log_->IsEnabled()) return;
    if (FLAG_ll_prof) LowLevelSnapshotPositionEvent(addr, pos);
    if (Serializer::enabled() && address_to_name_map_ != NULL) {
      const char* code_name = address_to_name_map_->Lookup(addr);
      if (code_name == NULL) return;  // Not a code object.
      LogMessageBuilder msg(this);
      msg.Append("%s,%d,", kLogEventsNames[SNAPSHOT_CODE_NAME_EVENT], pos);
      msg.AppendDoubleQuotedString(code_name);
      msg.Append("\n");
      msg.WriteToLogFile();
    }
    if (!FLAG_log_snapshot_positions) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,", kLogEventsNames[SNAPSHOT_POSITION_EVENT]);
    msg.AppendAddress(addr);
    msg.Append(",%d", pos);
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::SharedFunctionInfoMoveEvent(Address from, Address to) {
    MoveEventInternal(SHARED_FUNC_MOVE_EVENT, from, to);
  }
  
  
  void Logger::MoveEventInternal(LogEventsAndTags event,
                                 Address from,
                                 Address to) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,", kLogEventsNames[event]);
    msg.AppendAddress(from);
    msg.Append(',');
    msg.AppendAddress(to);
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::DeleteEventInternal(LogEventsAndTags event, Address from) {
    if (!log_->IsEnabled() || !FLAG_log_code) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,", kLogEventsNames[event]);
    msg.AppendAddress(from);
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::ResourceEvent(const char* name, const char* tag) {
    if (!log_->IsEnabled() || !FLAG_log) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,%s,", name, tag);
  
    uint32_t sec, usec;
    if (OS::GetUserTime(&sec, &usec) != -1) {
      msg.Append("%d,%d,", sec, usec);
    }
    msg.Append("%.0f", OS::TimeCurrentMillis());
  
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::SuspectReadEvent(Name* name, Object* obj) {
    if (!log_->IsEnabled() || !FLAG_log_suspect) return;
    LogMessageBuilder msg(this);
    String* class_name = obj->IsJSObject()
                         ? JSObject::cast(obj)->class_name()
                         : isolate_->heap()->empty_string();
    msg.Append("suspect-read,");
    msg.Append(class_name);
    msg.Append(',');
    if (name->IsString()) {
      msg.Append('"');
      msg.Append(String::cast(name));
      msg.Append('"');
    } else {
      AppendSymbolName(&msg, Symbol::cast(name));
    }
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  void Logger::HeapSampleBeginEvent(const char* space, const char* kind) {
    if (!log_->IsEnabled() || !FLAG_log_gc) return;
    LogMessageBuilder msg(this);
    // Using non-relative system time in order to be able to synchronize with
    // external memory profiling events (e.g. DOM memory size).
    msg.Append("heap-sample-begin,\"%s\",\"%s\",%.0f\n",
               space, kind, OS::TimeCurrentMillis());
    msg.WriteToLogFile();
  }
  
  
  void Logger::HeapSampleEndEvent(const char* space, const char* kind) {
    if (!log_->IsEnabled() || !FLAG_log_gc) return;
    LogMessageBuilder msg(this);
    msg.Append("heap-sample-end,\"%s\",\"%s\"\n", space, kind);
    msg.WriteToLogFile();
  }
  
  
  void Logger::HeapSampleItemEvent(const char* type, int number, int bytes) {
    if (!log_->IsEnabled() || !FLAG_log_gc) return;
    LogMessageBuilder msg(this);
    msg.Append("heap-sample-item,%s,%d,%d\n", type, number, bytes);
    msg.WriteToLogFile();
  }
  
  
  void Logger::DebugTag(const char* call_site_tag) {
    if (!log_->IsEnabled() || !FLAG_log) return;
    LogMessageBuilder msg(this);
    msg.Append("debug-tag,%s\n", call_site_tag);
    msg.WriteToLogFile();
  }
  
  
  void Logger::DebugEvent(const char* event_type, Vector<uint16_t> parameter) {
    if (!log_->IsEnabled() || !FLAG_log) return;
    StringBuilder s(parameter.length() + 1);
    for (int i = 0; i < parameter.length(); ++i) {
      s.AddCharacter(static_cast<char>(parameter[i]));
    }
    char* parameter_string = s.Finalize();
    LogMessageBuilder msg(this);
    msg.Append("debug-queue-event,%s,%15.3f,%s\n",
               event_type,
               OS::TimeCurrentMillis(),
               parameter_string);
    DeleteArray(parameter_string);
    msg.WriteToLogFile();
  }
  
  
  void Logger::TickEvent(TickSample* sample, bool overflow) {
    if (!log_->IsEnabled() || !FLAG_prof) return;
    LogMessageBuilder msg(this);
    msg.Append("%s,", kLogEventsNames[TICK_EVENT]);
    msg.AppendAddress(sample->pc);
    msg.Append(',');
    msg.AppendAddress(sample->sp);
    msg.Append(",%ld", static_cast<int>(OS::Ticks() - epoch_));
    if (sample->has_external_callback) {
      msg.Append(",1,");
      msg.AppendAddress(sample->external_callback);
    } else {
      msg.Append(",0,");
      msg.AppendAddress(sample->tos);
    }
    msg.Append(",%d", static_cast<int>(sample->state));
    if (overflow) {
      msg.Append(",overflow");
    }
    for (int i = 0; i < sample->frames_count; ++i) {
      msg.Append(',');
      msg.AppendAddress(sample->stack[i]);
    }
    msg.Append('\n');
    msg.WriteToLogFile();
  }
  
  
  bool Logger::IsProfilerPaused() {
    return profiler_ == NULL || profiler_->paused();
  }
  
  
  void Logger::PauseProfiler() {
    if (!log_->IsEnabled()) return;
    if (profiler_ != NULL) {
      // It is OK to have negative nesting.
      if (--cpu_profiler_nesting_ == 0) {
        profiler_->pause();
        if (FLAG_prof_lazy) {
          ticker_->Stop();
          FLAG_log_code = false;
          LOG(ISOLATE, UncheckedStringEvent("profiler", "pause"));
        }
        --logging_nesting_;
      }
    }
  }
  
  
  void Logger::ResumeProfiler() {
    if (!log_->IsEnabled()) return;
    if (profiler_ != NULL) {
      if (cpu_profiler_nesting_++ == 0) {
        ++logging_nesting_;
        if (FLAG_prof_lazy) {
          profiler_->Engage();
          LOG(ISOLATE, UncheckedStringEvent("profiler", "resume"));
          FLAG_log_code = true;
          LogCompiledFunctions();
          LogAccessorCallbacks();
          if (!ticker_->IsActive()) ticker_->Start();
        }
        profiler_->resume();
      }
    }
  }
  
  
  // This function can be called when Log's mutex is acquired,
  // either from main or Profiler's thread.
  void Logger::LogFailure() {
    PauseProfiler();
  }
  
  
  class EnumerateOptimizedFunctionsVisitor: public OptimizedFunctionVisitor {
   public:
    EnumerateOptimizedFunctionsVisitor(Handle<SharedFunctionInfo>* sfis,
                                       Handle<Code>* code_objects,
                                       int* count)
        : sfis_(sfis), code_objects_(code_objects), count_(count) { }
  
    virtual void EnterContext(Context* context) {}
    virtual void LeaveContext(Context* context) {}
  
    virtual void VisitFunction(JSFunction* function) {
      SharedFunctionInfo* sfi = SharedFunctionInfo::cast(function->shared());
      Object* maybe_script = sfi->script();
      if (maybe_script->IsScript()
          && !Script::cast(maybe_script)->HasValidSource()) return;
      if (sfis_ != NULL) {
        sfis_[*count_] = Handle<SharedFunctionInfo>(sfi);
      }
      if (code_objects_ != NULL) {
        ASSERT(function->code()->kind() == Code::OPTIMIZED_FUNCTION);
        code_objects_[*count_] = Handle<Code>(function->code());
      }
      *count_ = *count_ + 1;
    }
  
   private:
    Handle<SharedFunctionInfo>* sfis_;
    Handle<Code>* code_objects_;
    int* count_;
  };
  
  
  static int EnumerateCompiledFunctions(Heap* heap,
                                        Handle<SharedFunctionInfo>* sfis,
                                        Handle<Code>* code_objects) {
    HeapIterator iterator(heap);
    DisallowHeapAllocation no_gc;
    int compiled_funcs_count = 0;
  
    // Iterate the heap to find shared function info objects and record
    // the unoptimized code for them.
    for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
      if (!obj->IsSharedFunctionInfo()) continue;
      SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
      if (sfi->is_compiled()
          && (!sfi->script()->IsScript()
              || Script::cast(sfi->script())->HasValidSource())) {
        if (sfis != NULL) {
          sfis[compiled_funcs_count] = Handle<SharedFunctionInfo>(sfi);
        }
        if (code_objects != NULL) {
          code_objects[compiled_funcs_count] = Handle<Code>(sfi->code());
        }
        ++compiled_funcs_count;
      }
    }
  
    // Iterate all optimized functions in all contexts.
    EnumerateOptimizedFunctionsVisitor visitor(sfis,
                                               code_objects,
                                               &compiled_funcs_count);
    Deoptimizer::VisitAllOptimizedFunctions(heap->isolate(), &visitor);
  
    return compiled_funcs_count;
  }
  
  
  void Logger::LogCodeObject(Object* object) {
    Code* code_object = Code::cast(object);
    LogEventsAndTags tag = Logger::STUB_TAG;
    const char* description = "Unknown code from the snapshot";
    switch (code_object->kind()) {
      case Code::FUNCTION:
      case Code::OPTIMIZED_FUNCTION:
        return;  // We log this later using LogCompiledFunctions.
      case Code::UNARY_OP_IC:   // fall through
      case Code::BINARY_OP_IC:   // fall through
      case Code::COMPARE_IC:  // fall through
      case Code::COMPARE_NIL_IC:   // fall through
      case Code::TO_BOOLEAN_IC:  // fall through
      case Code::STUB:
        description =
            CodeStub::MajorName(CodeStub::GetMajorKey(code_object), true);
        if (description == NULL)
          description = "A stub from the snapshot";
        tag = Logger::STUB_TAG;
        break;
      case Code::REGEXP:
        description = "Regular expression code";
        tag = Logger::REG_EXP_TAG;
        break;
      case Code::BUILTIN:
        description = "A builtin from the snapshot";
        tag = Logger::BUILTIN_TAG;
        break;
      case Code::KEYED_LOAD_IC:
        description = "A keyed load IC from the snapshot";
        tag = Logger::KEYED_LOAD_IC_TAG;
        break;
      case Code::LOAD_IC:
        description = "A load IC from the snapshot";
        tag = Logger::LOAD_IC_TAG;
        break;
      case Code::STORE_IC:
        description = "A store IC from the snapshot";
        tag = Logger::STORE_IC_TAG;
        break;
      case Code::KEYED_STORE_IC:
        description = "A keyed store IC from the snapshot";
        tag = Logger::KEYED_STORE_IC_TAG;
        break;
      case Code::CALL_IC:
        description = "A call IC from the snapshot";
        tag = Logger::CALL_IC_TAG;
        break;
      case Code::KEYED_CALL_IC:
        description = "A keyed call IC from the snapshot";
        tag = Logger::KEYED_CALL_IC_TAG;
        break;
      case Code::NUMBER_OF_KINDS:
        break;
    }
    PROFILE(isolate_, CodeCreateEvent(tag, code_object, description));
  }
  
  
  void Logger::LogCodeInfo() {
    if (!log_->IsEnabled() || !FLAG_ll_prof) return;
  #if V8_TARGET_ARCH_IA32
    const char arch[] = "ia32";
  #elif V8_TARGET_ARCH_X64
    const char arch[] = "x64";
  #elif V8_TARGET_ARCH_ARM
    const char arch[] = "arm";
  #elif V8_TARGET_ARCH_MIPS
    const char arch[] = "mips";
  #else
    const char arch[] = "unknown";
  #endif
    LowLevelLogWriteBytes(arch, sizeof(arch));
  }
  
  
  void Logger::RegisterSnapshotCodeName(Code* code,
                                        const char* name,
                                        int name_size) {
    ASSERT(Serializer::enabled());
    if (address_to_name_map_ == NULL) {
      address_to_name_map_ = new NameMap;
    }
    address_to_name_map_->Insert(code->address(), name, name_size);
  }
  
  
  void Logger::LowLevelCodeCreateEvent(Code* code,
                                       const char* name,
                                       int name_size) {
    if (log_->ll_output_handle_ == NULL) return;
    LowLevelCodeCreateStruct event;
    event.name_size = name_size;
    event.code_address = code->instruction_start();
    ASSERT(event.code_address == code->address() + Code::kHeaderSize);
    event.code_size = code->instruction_size();
    LowLevelLogWriteStruct(event);
    LowLevelLogWriteBytes(name, name_size);
    LowLevelLogWriteBytes(
        reinterpret_cast<const char*>(code->instruction_start()),
        code->instruction_size());
  }
  
  
  void Logger::LowLevelCodeMoveEvent(Address from, Address to) {
    if (log_->ll_output_handle_ == NULL) return;
    LowLevelCodeMoveStruct event;
    event.from_address = from + Code::kHeaderSize;
    event.to_address = to + Code::kHeaderSize;
    LowLevelLogWriteStruct(event);
  }
  
  
  void Logger::LowLevelCodeDeleteEvent(Address from) {
    if (log_->ll_output_handle_ == NULL) return;
    LowLevelCodeDeleteStruct event;
    event.address = from + Code::kHeaderSize;
    LowLevelLogWriteStruct(event);
  }
  
  
  void Logger::LowLevelSnapshotPositionEvent(Address addr, int pos) {
    if (log_->ll_output_handle_ == NULL) return;
    LowLevelSnapshotPositionStruct event;
    event.address = addr + Code::kHeaderSize;
    event.position = pos;
    LowLevelLogWriteStruct(event);
  }
  
  
  void Logger::LowLevelLogWriteBytes(const char* bytes, int size) {
    size_t rv = fwrite(bytes, 1, size, log_->ll_output_handle_);
    ASSERT(static_cast<size_t>(size) == rv);
    USE(rv);
  }
  
  
  void Logger::LogCodeObjects() {
    Heap* heap = isolate_->heap();
    heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                            "Logger::LogCodeObjects");
    HeapIterator iterator(heap);
    DisallowHeapAllocation no_gc;
    for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
      if (obj->IsCode()) LogCodeObject(obj);
    }
  }
  
  
  void Logger::LogExistingFunction(Handle<SharedFunctionInfo> shared,
                                   Handle<Code> code) {
    Handle<String> func_name(shared->DebugName());
    if (shared->script()->IsScript()) {
      Handle<Script> script(Script::cast(shared->script()));
      if (script->name()->IsString()) {
        Handle<String> script_name(String::cast(script->name()));
        int line_num = GetScriptLineNumber(script, shared->start_position());
        if (line_num > 0) {
          PROFILE(isolate_,
                  CodeCreateEvent(
                      Logger::ToNativeByScript(Logger::LAZY_COMPILE_TAG, *script),
                      *code, *shared, NULL,
                      *script_name, line_num + 1));
        } else {
          // Can't distinguish eval and script here, so always use Script.
          PROFILE(isolate_,
                  CodeCreateEvent(
                      Logger::ToNativeByScript(Logger::SCRIPT_TAG, *script),
                      *code, *shared, NULL, *script_name));
        }
      } else {
        PROFILE(isolate_,
                CodeCreateEvent(
                    Logger::ToNativeByScript(Logger::LAZY_COMPILE_TAG, *script),
                    *code, *shared, NULL, *func_name));
      }
    } else if (shared->IsApiFunction()) {
      // API function.
      FunctionTemplateInfo* fun_data = shared->get_api_func_data();
      Object* raw_call_data = fun_data->call_code();
      if (!raw_call_data->IsUndefined()) {
        CallHandlerInfo* call_data = CallHandlerInfo::cast(raw_call_data);
        Object* callback_obj = call_data->callback();
        Address entry_point = v8::ToCData<Address>(callback_obj);
        PROFILE(isolate_, CallbackEvent(*func_name, entry_point));
      }
    } else {
      PROFILE(isolate_,
              CodeCreateEvent(
                  Logger::LAZY_COMPILE_TAG, *code, *shared, NULL, *func_name));
    }
  }
  
  
  void Logger::LogCompiledFunctions() {
    Heap* heap = isolate_->heap();
    heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                            "Logger::LogCompiledFunctions");
    HandleScope scope(isolate_);
    const int compiled_funcs_count = EnumerateCompiledFunctions(heap, NULL, NULL);
    ScopedVector< Handle<SharedFunctionInfo> > sfis(compiled_funcs_count);
    ScopedVector< Handle<Code> > code_objects(compiled_funcs_count);
    EnumerateCompiledFunctions(heap, sfis.start(), code_objects.start());
  
    // During iteration, there can be heap allocation due to
    // GetScriptLineNumber call.
    for (int i = 0; i < compiled_funcs_count; ++i) {
      if (*code_objects[i] == Isolate::Current()->builtins()->builtin(
          Builtins::kLazyCompile))
        continue;
      LogExistingFunction(sfis[i], code_objects[i]);
    }
  }
  
  
  void Logger::LogAccessorCallbacks() {
    Heap* heap = isolate_->heap();
    heap->CollectAllGarbage(Heap::kMakeHeapIterableMask,
                            "Logger::LogAccessorCallbacks");
    HeapIterator iterator(heap);
    DisallowHeapAllocation no_gc;
    for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
      if (!obj->IsExecutableAccessorInfo()) continue;
      ExecutableAccessorInfo* ai = ExecutableAccessorInfo::cast(obj);
      if (!ai->name()->IsName()) continue;
      Address getter_entry = v8::ToCData<Address>(ai->getter());
      Name* name = Name::cast(ai->name());
      if (getter_entry != 0) {
        PROFILE(isolate_, GetterCallbackEvent(name, getter_entry));
      }
      Address setter_entry = v8::ToCData<Address>(ai->setter());
      if (setter_entry != 0) {
        PROFILE(isolate_, SetterCallbackEvent(name, setter_entry));
      }
    }
  }
  
  
  bool Logger::SetUp(Isolate* isolate) {
    // Tests and EnsureInitialize() can call this twice in a row. It's harmless.
    if (is_initialized_) return true;
    is_initialized_ = true;
  
    // --ll-prof implies --log-code and --log-snapshot-positions.
    if (FLAG_ll_prof) {
      FLAG_log_snapshot_positions = true;
    }
  
    // --prof_lazy controls --log-code, implies --noprof_auto.
    if (FLAG_prof_lazy) {
      FLAG_log_code = false;
      FLAG_prof_auto = false;
    }
  
    log_->Initialize();
  
    if (FLAG_ll_prof) LogCodeInfo();
  
    ticker_ = new Ticker(isolate, kSamplingIntervalMs);
  
    if (Log::InitLogAtStart()) {
      logging_nesting_ = 1;
    }
  
    if (FLAG_prof) {
      profiler_ = new Profiler(isolate);
      if (!FLAG_prof_auto) {
        profiler_->pause();
      } else {
        logging_nesting_ = 1;
      }
      if (!FLAG_prof_lazy) {
        profiler_->Engage();
      }
    }
  
    if (FLAG_log_internal_timer_events || FLAG_prof) epoch_ = OS::Ticks();
  
    return true;
  }
  
  
  void Logger::SetCodeEventHandler(uint32_t options,
                                   JitCodeEventHandler event_handler) {
    code_event_handler_ = event_handler;
  
    if (code_event_handler_ != NULL && (options & kJitCodeEventEnumExisting)) {
      HandleScope scope(Isolate::Current());
      LogCodeObjects();
      LogCompiledFunctions();
    }
  }
  
  
  Sampler* Logger::sampler() {
    return ticker_;
  }
  
  
  FILE* Logger::TearDown() {
    if (!is_initialized_) return NULL;
    is_initialized_ = false;
  
    // Stop the profiler before closing the file.
    if (profiler_ != NULL) {
      profiler_->Disengage();
      delete profiler_;
      profiler_ = NULL;
    }
  
    delete ticker_;
    ticker_ = NULL;
  
    return log_->Close();
  }
  
  } }  // namespace v8::internal
  