Import V8 r1682 from trunk.

v8/REVISION has svn URL and revision number:
http://v8.googlecode.com/svn/trunk@1682

1 files changed, 1193 insertions, 0 deletions

diff --git a/v8/src/log.cc b/v8/src/log.cc
new file mode 100644
index 0000000..d9e304d
--- /dev/null
+++ b/v8/src/log.cc
@@ -0,0 +1,1193 @@
+// Copyright 2009 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 "log.h"
+#include "macro-assembler.h"
+#include "platform.h"
+#include "serialize.h"
+#include "string-stream.h"
+
+namespace v8 { namespace internal {
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+
+//
+// Sliding state window.  Updates counters to keep track of the last
+// window of kBufferSize states.  This is useful to track where we
+// spent our time.
+//
+class SlidingStateWindow {
+ public:
+  SlidingStateWindow();
+  ~SlidingStateWindow();
+  void AddState(StateTag state);
+
+ private:
+  static const int kBufferSize = 256;
+  int current_index_;
+  bool is_full_;
+  byte buffer_[kBufferSize];
+
+
+  void IncrementStateCounter(StateTag state) {
+    Counters::state_counters[state].Increment();
+  }
+
+
+  void DecrementStateCounter(StateTag state) {
+    Counters::state_counters[state].Decrement();
+  }
+};
+
+
+//
+// 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:
+  Profiler();
+  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.
+  static bool paused() { return paused_; }
+  static void pause() { paused_ = true; }
+  static void resume() { paused_ = false; }
+
+ private:
+  // Returns the next index in the cyclic buffer.
+  int Succ(int index) { return (index + 1) % kBufferSize; }
+
+  // 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 worker thread should continue running.
+  bool running_;
+
+  // Tells whether we are currently recording tick samples.
+  static bool paused_;
+};
+
+bool Profiler::paused_ = false;
+
+
+//
+// StackTracer implementation
+//
+void StackTracer::Trace(TickSample* sample) {
+  if (sample->state == GC) {
+    sample->frames_count = 0;
+    return;
+  }
+
+  SafeStackTraceFrameIterator it(
+      reinterpret_cast<Address>(sample->fp),
+      reinterpret_cast<Address>(sample->sp),
+      reinterpret_cast<Address>(sample->sp),
+      reinterpret_cast<Address>(low_stack_bound_));
+  int i = 0;
+  while (!it.done() && i < TickSample::kMaxFramesCount) {
+    sample->stack[i++] = it.frame()->pc();
+    it.Advance();
+  }
+  sample->frames_count = i;
+}
+
+
+//
+// Ticker used to provide ticks to the profiler and the sliding state
+// window.
+//
+class Ticker: public Sampler {
+ public:
+  explicit Ticker(int interval, unsigned int low_stack_bound):
+      Sampler(interval, FLAG_prof), window_(NULL), profiler_(NULL),
+      stack_tracer_(low_stack_bound) {}
+
+  ~Ticker() { if (IsActive()) Stop(); }
+
+  void Tick(TickSample* sample) {
+    if (IsProfiling()) stack_tracer_.Trace(sample);
+    if (profiler_) profiler_->Insert(sample);
+    if (window_) window_->AddState(sample->state);
+  }
+
+  void SetWindow(SlidingStateWindow* window) {
+    window_ = window;
+    if (!IsActive()) Start();
+  }
+
+  void ClearWindow() {
+    window_ = NULL;
+    if (!profiler_ && IsActive()) Stop();
+  }
+
+  void SetProfiler(Profiler* profiler) {
+    profiler_ = profiler;
+    if (!IsActive()) Start();
+  }
+
+  void ClearProfiler() {
+    profiler_ = NULL;
+    if (!window_ && IsActive()) Stop();
+  }
+
+ private:
+  SlidingStateWindow* window_;
+  Profiler* profiler_;
+  StackTracer stack_tracer_;
+};
+
+
+//
+// SlidingStateWindow implementation.
+//
+SlidingStateWindow::SlidingStateWindow(): current_index_(0), is_full_(false) {
+  for (int i = 0; i < kBufferSize; i++) {
+    buffer_[i] = static_cast<byte>(OTHER);
+  }
+  Logger::ticker_->SetWindow(this);
+}
+
+
+SlidingStateWindow::~SlidingStateWindow() {
+  Logger::ticker_->ClearWindow();
+}
+
+
+void SlidingStateWindow::AddState(StateTag state) {
+  if (is_full_) {
+    DecrementStateCounter(static_cast<StateTag>(buffer_[current_index_]));
+  } else if (current_index_ == kBufferSize - 1) {
+    is_full_ = true;
+  }
+  buffer_[current_index_] = static_cast<byte>(state);
+  IncrementStateCounter(state);
+  ASSERT(IsPowerOf2(kBufferSize));
+  current_index_ = (current_index_ + 1) & (kBufferSize - 1);
+}
+
+
+//
+// Profiler implementation.
+//
+Profiler::Profiler() {
+  buffer_semaphore_ = OS::CreateSemaphore(0);
+  head_ = 0;
+  tail_ = 0;
+  overflow_ = false;
+  running_ = false;
+}
+
+
+void Profiler::Engage() {
+  OS::LogSharedLibraryAddresses();
+
+  // Start thread processing the profiler buffer.
+  running_ = true;
+  Start();
+
+  // Register to get ticks.
+  Logger::ticker_->SetProfiler(this);
+
+  LOG(UncheckedStringEvent("profiler", "begin"));
+}
+
+
+void Profiler::Disengage() {
+  // Stop receiving ticks.
+  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;
+  Insert(&sample);
+  Join();
+
+  LOG(UncheckedStringEvent("profiler", "end"));
+}
+
+
+void Profiler::Run() {
+  TickSample sample;
+  bool overflow = Logger::profiler_->Remove(&sample);
+  while (running_) {
+    LOG(TickEvent(&sample, overflow));
+    overflow = Logger::profiler_->Remove(&sample);
+  }
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+// Utility class for formatting log messages. It fills the message into the
+// static buffer in Logger.
+class LogMessageBuilder BASE_EMBEDDED {
+ public:
+  explicit LogMessageBuilder();
+  ~LogMessageBuilder() { }
+
+  void Append(const char* format, ...);
+  void Append(const char* format, va_list args);
+  void Append(const char c);
+  void Append(String *str);
+  void AppendDetailed(String* str, bool show_impl_info);
+
+  void WriteToLogFile();
+  void WriteCStringToLogFile(const char* str);
+
+ private:
+  ScopedLock sl;
+  int pos_;
+};
+
+
+// Create a message builder starting from position 0. This acquires the mutex
+// in the logger as well.
+LogMessageBuilder::LogMessageBuilder(): sl(Logger::mutex_), pos_(0) {
+  ASSERT(Logger::message_buffer_ != NULL);
+}
+
+
+// Append string data to the log message.
+void LogMessageBuilder::Append(const char* format, ...) {
+  Vector<char> buf(Logger::message_buffer_ + pos_,
+                   Logger::kMessageBufferSize - pos_);
+  va_list args;
+  va_start(args, format);
+  Append(format, args);
+  va_end(args);
+  ASSERT(pos_ <= Logger::kMessageBufferSize);
+}
+
+
+// Append string data to the log message.
+void LogMessageBuilder::Append(const char* format, va_list args) {
+  Vector<char> buf(Logger::message_buffer_ + pos_,
+                   Logger::kMessageBufferSize - pos_);
+  int result = v8::internal::OS::VSNPrintF(buf, format, args);
+
+  // Result is -1 if output was truncated.
+  if (result >= 0) {
+    pos_ += result;
+  } else {
+    pos_ = Logger::kMessageBufferSize;
+  }
+  ASSERT(pos_ <= Logger::kMessageBufferSize);
+}
+
+
+// Append a character to the log message.
+void LogMessageBuilder::Append(const char c) {
+  if (pos_ < Logger::kMessageBufferSize) {
+    Logger::message_buffer_[pos_++] = c;
+  }
+  ASSERT(pos_ <= Logger::kMessageBufferSize);
+}
+
+
+// Append a heap string.
+void LogMessageBuilder::Append(String* str) {
+  AssertNoAllocation no_heap_allocation;  // Ensure string stay valid.
+  int length = str->length();
+  for (int i = 0; i < length; i++) {
+    Append(static_cast<char>(str->Get(i)));
+  }
+}
+
+void LogMessageBuilder::AppendDetailed(String* str, bool show_impl_info) {
+  AssertNoAllocation no_heap_allocation;  // Ensure string stay valid.
+  int len = str->length();
+  if (len > 0x1000)
+    len = 0x1000;
+  if (show_impl_info) {
+    Append(StringShape(str).IsAsciiRepresentation() ? 'a' : '2');
+    if (StringShape(str).IsExternal())
+      Append('e');
+    if (StringShape(str).IsSymbol())
+      Append('#');
+    Append(":%i:", str->length());
+  }
+  for (int i = 0; i < len; i++) {
+    uc32 c = str->Get(i);
+    if (c > 0xff) {
+      Append("\\u%04x", c);
+    } else if (c < 32 || c > 126) {
+      Append("\\x%02x", c);
+    } else if (c == ',') {
+      Append("\\,");
+    } else if (c == '\\') {
+      Append("\\\\");
+    } else {
+      Append("%lc", c);
+    }
+  }
+}
+
+// Write the log message to the log file currently opened.
+void LogMessageBuilder::WriteToLogFile() {
+  ASSERT(pos_ <= Logger::kMessageBufferSize);
+  size_t rv = fwrite(Logger::message_buffer_, 1, pos_, Logger::logfile_);
+  ASSERT(rv == static_cast<size_t>(pos_));
+  USE(rv);
+}
+
+// Write a null-terminated string to to the log file currently opened.
+void LogMessageBuilder::WriteCStringToLogFile(const char* str) {
+  size_t len = strlen(str);
+  size_t rv = fwrite(str, 1, len, Logger::logfile_);
+  ASSERT(rv == len);
+  USE(rv);
+}
+#endif
+
+
+//
+// Logger class implementation.
+//
+Ticker* Logger::ticker_ = NULL;
+char* Logger::message_buffer_ = NULL;
+FILE* Logger::logfile_ = NULL;
+Profiler* Logger::profiler_ = NULL;
+Mutex* Logger::mutex_ = NULL;
+VMState* Logger::current_state_ = NULL;
+VMState Logger::bottom_state_(EXTERNAL);
+SlidingStateWindow* Logger::sliding_state_window_ = NULL;
+
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+
+void Logger::Preamble(const char* content) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.WriteCStringToLogFile(content);
+#endif
+}
+
+
+void Logger::StringEvent(const char* name, const char* value) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (FLAG_log) UncheckedStringEvent(name, value);
+#endif
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+void Logger::UncheckedStringEvent(const char* name, const char* value) {
+  if (logfile_ == NULL) return;
+  LogMessageBuilder msg;
+  msg.Append("%s,\"%s\"\n", name, value);
+  msg.WriteToLogFile();
+}
+#endif
+
+
+void Logger::IntEvent(const char* name, int value) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log) return;
+  LogMessageBuilder msg;
+  msg.Append("%s,%d\n", name, value);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::HandleEvent(const char* name, Object** location) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_handles) return;
+  LogMessageBuilder msg;
+  msg.Append("%s,0x%x\n", name,
+             reinterpret_cast<unsigned int>(location));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+// ApiEvent is private so all the calls come from the Logger class.  It is the
+// caller's responsibility to ensure that logfile_ is not NULL and that
+// FLAG_log_api is true.
+void Logger::ApiEvent(const char* format, ...) {
+  ASSERT(logfile_ != NULL && FLAG_log_api);
+  LogMessageBuilder msg;
+  va_list ap;
+  va_start(ap, format);
+  msg.Append(format, ap);
+  va_end(ap);
+  msg.WriteToLogFile();
+}
+#endif
+
+
+void Logger::ApiNamedSecurityCheck(Object* key) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  if (key->IsString()) {
+    SmartPointer<char> str =
+        String::cast(key)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+    ApiEvent("api,check-security,\"%s\"\n", *str);
+  } else if (key->IsUndefined()) {
+    ApiEvent("api,check-security,undefined\n");
+  } else {
+    ApiEvent("api,check-security,['no-name']\n");
+  }
+#endif
+}
+
+
+void Logger::SharedLibraryEvent(const char* library_path,
+                                unsigned start,
+                                unsigned end) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_prof) return;
+  LogMessageBuilder msg;
+  msg.Append("shared-library,\"%s\",0x%08x,0x%08x\n", library_path,
+             start, end);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::SharedLibraryEvent(const wchar_t* library_path,
+                                unsigned start,
+                                unsigned end) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_prof) return;
+  LogMessageBuilder msg;
+  msg.Append("shared-library,\"%ls\",0x%08x,0x%08x\n", library_path,
+             start, end);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+void Logger::LogRegExpSource(Handle<JSRegExp> regexp) {
+  // Prints "/" + re.source + "/" +
+  //      (re.global?"g":"") + (re.ignorecase?"i":"") + (re.multiline?"m":"")
+  LogMessageBuilder msg;
+
+  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();
+}
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+
+void Logger::RegExpCompileEvent(Handle<JSRegExp> regexp, bool in_cache) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_regexp) return;
+  LogMessageBuilder msg;
+  msg.Append("regexp-compile,");
+  LogRegExpSource(regexp);
+  msg.Append(in_cache ? ",hit\n" : ",miss\n");
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::LogRuntime(Vector<const char> format, JSArray* args) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_runtime) return;
+  HandleScope scope;
+  LogMessageBuilder msg;
+  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');
+      Object* obj = args->GetElement(format[i] - '0');
+      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();
+#endif
+}
+
+
+void Logger::ApiIndexedSecurityCheck(uint32_t index) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  ApiEvent("api,check-security,%u\n", index);
+#endif
+}
+
+
+void Logger::ApiNamedPropertyAccess(const char* tag,
+                                    JSObject* holder,
+                                    Object* name) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  ASSERT(name->IsString());
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  String* class_name_obj = holder->class_name();
+  SmartPointer<char> class_name =
+      class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  SmartPointer<char> property_name =
+      String::cast(name)->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  Logger::ApiEvent("api,%s,\"%s\",\"%s\"\n", tag, *class_name, *property_name);
+#endif
+}
+
+void Logger::ApiIndexedPropertyAccess(const char* tag,
+                                      JSObject* holder,
+                                      uint32_t index) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  String* class_name_obj = holder->class_name();
+  SmartPointer<char> class_name =
+      class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  Logger::ApiEvent("api,%s,\"%s\",%u\n", tag, *class_name, index);
+#endif
+}
+
+void Logger::ApiObjectAccess(const char* tag, JSObject* object) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  String* class_name_obj = object->class_name();
+  SmartPointer<char> class_name =
+      class_name_obj->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  Logger::ApiEvent("api,%s,\"%s\"\n", tag, *class_name);
+#endif
+}
+
+
+void Logger::ApiEntryCall(const char* name) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_api) return;
+  Logger::ApiEvent("api,%s\n", name);
+#endif
+}
+
+
+void Logger::NewEvent(const char* name, void* object, size_t size) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log) return;
+  LogMessageBuilder msg;
+  msg.Append("new,%s,0x%x,%u\n", name,
+             reinterpret_cast<unsigned int>(object),
+             static_cast<unsigned int>(size));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::DeleteEvent(const char* name, void* object) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log) return;
+  LogMessageBuilder msg;
+  msg.Append("delete,%s,0x%x\n", name,
+             reinterpret_cast<unsigned int>(object));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeCreateEvent(const char* tag, Code* code, const char* comment) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-creation,%s,0x%x,%d,\"", tag,
+             reinterpret_cast<unsigned int>(code->address()),
+             code->ExecutableSize());
+  for (const char* p = comment; *p != '\0'; p++) {
+    if (*p == '"') {
+      msg.Append('\\');
+    }
+    msg.Append(*p);
+  }
+  msg.Append('"');
+  msg.Append('\n');
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeCreateEvent(const char* tag, Code* code, String* name) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  SmartPointer<char> str =
+      name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  msg.Append("code-creation,%s,0x%x,%d,\"%s\"\n", tag,
+             reinterpret_cast<unsigned int>(code->address()),
+             code->ExecutableSize(), *str);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeCreateEvent(const char* tag, Code* code, String* name,
+                             String* source, int line) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  SmartPointer<char> str =
+      name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  SmartPointer<char> sourcestr =
+      source->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
+  msg.Append("code-creation,%s,0x%x,%d,\"%s %s:%d\"\n", tag,
+             reinterpret_cast<unsigned int>(code->address()),
+             code->ExecutableSize(),
+             *str, *sourcestr, line);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeCreateEvent(const char* tag, Code* code, int args_count) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-creation,%s,0x%x,%d,\"args_count: %d\"\n", tag,
+             reinterpret_cast<unsigned int>(code->address()),
+             code->ExecutableSize(),
+             args_count);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::RegExpCodeCreateEvent(Code* code, String* source) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-creation,%s,0x%x,%d,\"", "RegExp",
+             reinterpret_cast<unsigned int>(code->address()),
+             code->ExecutableSize());
+  msg.AppendDetailed(source, false);
+  msg.Append("\"\n");
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeAllocateEvent(Code* code, Assembler* assem) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-allocate,0x%x,0x%x\n",
+             reinterpret_cast<unsigned int>(code->address()),
+             reinterpret_cast<unsigned int>(assem));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeMoveEvent(Address from, Address to) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-move,0x%x,0x%x\n",
+             reinterpret_cast<unsigned int>(from),
+             reinterpret_cast<unsigned int>(to));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::CodeDeleteEvent(Address from) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("code-delete,0x%x\n", reinterpret_cast<unsigned int>(from));
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::BeginCodeRegionEvent(CodeRegion* region,
+                                  Assembler* masm,
+                                  const char* name) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("begin-code-region,0x%x,0x%x,0x%x,%s\n",
+             reinterpret_cast<unsigned int>(region),
+             reinterpret_cast<unsigned int>(masm),
+             masm->pc_offset(),
+             name);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::EndCodeRegionEvent(CodeRegion* region, Assembler* masm) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_code) return;
+  LogMessageBuilder msg;
+  msg.Append("end-code-region,0x%x,0x%x,0x%x\n",
+             reinterpret_cast<unsigned int>(region),
+             reinterpret_cast<unsigned int>(masm),
+             masm->pc_offset());
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::ResourceEvent(const char* name, const char* tag) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log) return;
+  LogMessageBuilder msg;
+  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();
+#endif
+}
+
+
+void Logger::SuspectReadEvent(String* name, Object* obj) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_suspect) return;
+  LogMessageBuilder msg;
+  String* class_name = obj->IsJSObject()
+                       ? JSObject::cast(obj)->class_name()
+                       : Heap::empty_string();
+  ScopedLock sl(mutex_);
+  msg.Append("suspect-read,");
+  msg.Append(class_name);
+  msg.Append(',');
+  msg.Append('"');
+  msg.Append(name);
+  msg.Append('"');
+  msg.Append('\n');
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::HeapSampleBeginEvent(const char* space, const char* kind) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_gc) return;
+  LogMessageBuilder msg;
+  msg.Append("heap-sample-begin,\"%s\",\"%s\"\n", space, kind);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::HeapSampleEndEvent(const char* space, const char* kind) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_gc) return;
+  LogMessageBuilder msg;
+  msg.Append("heap-sample-end,\"%s\",\"%s\"\n", space, kind);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::HeapSampleItemEvent(const char* type, int number, int bytes) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log_gc) return;
+  LogMessageBuilder msg;
+  msg.Append("heap-sample-item,%s,%d,%d\n", type, number, bytes);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::DebugTag(const char* call_site_tag) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !FLAG_log) return;
+  LogMessageBuilder msg;
+  msg.Append("debug-tag,%s\n", call_site_tag);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+void Logger::DebugEvent(const char* event_type, Vector<uint16_t> parameter) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (logfile_ == NULL || !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;
+  msg.Append("debug-queue-event,%s,%15.3f,%s\n",
+             event_type,
+             OS::TimeCurrentMillis(),
+             parameter_string);
+  DeleteArray(parameter_string);
+  msg.WriteToLogFile();
+#endif
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+void Logger::TickEvent(TickSample* sample, bool overflow) {
+  if (logfile_ == NULL || !FLAG_prof) return;
+  LogMessageBuilder msg;
+  msg.Append("tick,0x%x,0x%x,%d", sample->pc, sample->sp,
+             static_cast<int>(sample->state));
+  if (overflow) {
+    msg.Append(",overflow");
+  }
+  for (int i = 0; i < sample->frames_count; ++i) {
+    msg.Append(",0x%x", reinterpret_cast<uint32_t>(sample->stack[i]));
+  }
+  msg.Append('\n');
+  msg.WriteToLogFile();
+}
+
+
+bool Logger::IsProfilerPaused() {
+  return profiler_->paused();
+}
+
+
+void Logger::PauseProfiler() {
+  profiler_->pause();
+}
+
+
+void Logger::ResumeProfiler() {
+  profiler_->resume();
+}
+#endif
+
+
+bool Logger::Setup() {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // --log-all enables all the log flags.
+  if (FLAG_log_all) {
+    FLAG_log_runtime = true;
+    FLAG_log_api = true;
+    FLAG_log_code = true;
+    FLAG_log_gc = true;
+    FLAG_log_suspect = true;
+    FLAG_log_handles = true;
+    FLAG_log_regexp = true;
+  }
+
+  // --prof implies --log-code.
+  if (FLAG_prof) FLAG_log_code = true;
+
+  bool open_log_file = FLAG_log || FLAG_log_runtime || FLAG_log_api
+      || FLAG_log_code || FLAG_log_gc || FLAG_log_handles || FLAG_log_suspect
+      || FLAG_log_regexp || FLAG_log_state_changes;
+
+  // If we're logging anything, we need to open the log file.
+  if (open_log_file) {
+    if (strcmp(FLAG_logfile, "-") == 0) {
+      logfile_ = stdout;
+    } else if (strchr(FLAG_logfile, '%') != NULL) {
+      // If there's a '%' in the log file name we have to expand
+      // placeholders.
+      HeapStringAllocator allocator;
+      StringStream stream(&allocator);
+      for (const char* p = FLAG_logfile; *p; p++) {
+        if (*p == '%') {
+          p++;
+          switch (*p) {
+            case '\0':
+              // If there's a % at the end of the string we back up
+              // one character so we can escape the loop properly.
+              p--;
+              break;
+            case 't': {
+              // %t expands to the current time in milliseconds.
+              uint32_t time = static_cast<uint32_t>(OS::TimeCurrentMillis());
+              stream.Add("%u", time);
+              break;
+            }
+            case '%':
+              // %% expands (contracts really) to %.
+              stream.Put('%');
+              break;
+            default:
+              // All other %'s expand to themselves.
+              stream.Put('%');
+              stream.Put(*p);
+              break;
+          }
+        } else {
+          stream.Put(*p);
+        }
+      }
+      SmartPointer<const char> expanded = stream.ToCString();
+      logfile_ = OS::FOpen(*expanded, OS::LogFileOpenMode);
+    } else {
+      logfile_ = OS::FOpen(FLAG_logfile, OS::LogFileOpenMode);
+    }
+    message_buffer_ = NewArray<char>(kMessageBufferSize);
+    mutex_ = OS::CreateMutex();
+  }
+
+  current_state_ = &bottom_state_;
+
+  // as log is initialized early with V8, we can assume that JS execution
+  // frames can never reach this point on stack
+  int stack_var;
+  ticker_ = new Ticker(1, reinterpret_cast<unsigned int>(&stack_var));
+
+  if (FLAG_sliding_state_window && sliding_state_window_ == NULL) {
+    sliding_state_window_ = new SlidingStateWindow();
+  }
+
+  if (FLAG_prof) {
+    profiler_ = new Profiler();
+    if (!FLAG_prof_auto)
+      profiler_->pause();
+    profiler_->Engage();
+  }
+
+  return true;
+
+#else
+  return false;
+#endif
+}
+
+
+void Logger::TearDown() {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // Stop the profiler before closing the file.
+  if (profiler_ != NULL) {
+    profiler_->Disengage();
+    delete profiler_;
+    profiler_ = NULL;
+  }
+
+  delete sliding_state_window_;
+
+  delete ticker_;
+
+  if (logfile_ != NULL) {
+    fclose(logfile_);
+    logfile_ = NULL;
+    delete mutex_;
+    mutex_ = NULL;
+    DeleteArray(message_buffer_);
+  }
+#endif
+}
+
+
+void Logger::EnableSlidingStateWindow() {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  // If the ticker is NULL, Logger::Setup has not been called yet.  In
+  // that case, we set the sliding_state_window flag so that the
+  // sliding window computation will be started when Logger::Setup is
+  // called.
+  if (ticker_ == NULL) {
+    FLAG_sliding_state_window = true;
+    return;
+  }
+  // Otherwise, if the sliding state window computation has not been
+  // started we do it now.
+  if (sliding_state_window_ == NULL) {
+    sliding_state_window_ = new SlidingStateWindow();
+  }
+#endif
+}
+
+
+//
+// VMState class implementation.  A simple stack of VM states held by the
+// logger and partially threaded through the call stack.  States are pushed by
+// VMState construction and popped by destruction.
+//
+#ifdef ENABLE_LOGGING_AND_PROFILING
+static const char* StateToString(StateTag state) {
+  switch (state) {
+    case JS:
+      return "JS";
+    case GC:
+      return "GC";
+    case COMPILER:
+      return "COMPILER";
+    case OTHER:
+      return "OTHER";
+    default:
+      UNREACHABLE();
+      return NULL;
+  }
+}
+
+VMState::VMState(StateTag state) {
+#if !defined(ENABLE_HEAP_PROTECTION)
+  // When not protecting the heap, there is no difference between
+  // EXTERNAL and OTHER.  As an optimizatin in that case, we will not
+  // perform EXTERNAL->OTHER transitions through the API.  We thus
+  // compress the two states into one.
+  if (state == EXTERNAL) state = OTHER;
+#endif
+  state_ = state;
+  previous_ = Logger::current_state_;
+  Logger::current_state_ = this;
+
+  if (FLAG_log_state_changes) {
+    LOG(UncheckedStringEvent("Entering", StateToString(state_)));
+    if (previous_ != NULL) {
+      LOG(UncheckedStringEvent("From", StateToString(previous_->state_)));
+    }
+  }
+
+#ifdef ENABLE_HEAP_PROTECTION
+  if (FLAG_protect_heap && previous_ != NULL) {
+    if (state_ == EXTERNAL) {
+      // We are leaving V8.
+      ASSERT(previous_->state_ != EXTERNAL);
+      Heap::Protect();
+    } else if (previous_->state_ == EXTERNAL) {
+      // We are entering V8.
+      Heap::Unprotect();
+    }
+  }
+#endif
+}
+
+
+VMState::~VMState() {
+  Logger::current_state_ = previous_;
+
+  if (FLAG_log_state_changes) {
+    LOG(UncheckedStringEvent("Leaving", StateToString(state_)));
+    if (previous_ != NULL) {
+      LOG(UncheckedStringEvent("To", StateToString(previous_->state_)));
+    }
+  }
+
+#ifdef ENABLE_HEAP_PROTECTION
+  if (FLAG_protect_heap && previous_ != NULL) {
+    if (state_ == EXTERNAL) {
+      // We are reentering V8.
+      ASSERT(previous_->state_ != EXTERNAL);
+      Heap::Unprotect();
+    } else if (previous_->state_ == EXTERNAL) {
+      // We are leaving V8.
+      Heap::Protect();
+    }
+  }
+#endif
+}
+#endif
+
+} }  // namespace v8::internal