blob: e083f01a44e38b43bff069e3ed4a3cfe48cf6486 [file] [log] [blame]
// 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 "global-handles.h"
#include "log.h"
#include "macro-assembler.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 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.
static bool paused_;
};
bool Profiler::paused_ = false;
//
// StackTracer implementation
//
void StackTracer::Trace(TickSample* sample) {
sample->function = NULL;
sample->frames_count = 0;
if (sample->state == GC) return;
const Address js_entry_sp = Top::js_entry_sp(Top::GetCurrentThread());
if (js_entry_sp == 0) {
// Not executing JS now.
return;
}
const Address functionAddr =
sample->fp + JavaScriptFrameConstants::kFunctionOffset;
if (SafeStackFrameIterator::IsWithinBounds(sample->sp, js_entry_sp,
functionAddr)) {
sample->function = Memory::Address_at(functionAddr) - kHeapObjectTag;
}
int i = 0;
const Address callback = VMState::external_callback();
if (callback != NULL) {
sample->stack[i++] = callback;
}
SafeStackTraceFrameIterator it(sample->fp, sample->sp,
sample->sp, js_entry_sp);
while (!it.done() && i < TickSample::kMaxFramesCount) {
sample->stack[i++] = reinterpret_cast<Address>(it.frame()->function());
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):
Sampler(interval, FLAG_prof), window_(NULL), profiler_(NULL) {}
~Ticker() { if (IsActive()) Stop(); }
void SampleStack(TickSample* sample) {
StackTracer::Trace(sample);
}
void Tick(TickSample* 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 (!FLAG_prof_lazy && !IsActive()) Start();
}
void ClearProfiler() {
profiler_ = NULL;
if (!window_ && IsActive()) Stop();
}
private:
SlidingStateWindow* window_;
Profiler* profiler_;
};
//
// 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()
: head_(0),
tail_(0),
overflow_(false),
buffer_semaphore_(OS::CreateSemaphore(0)),
engaged_(false),
running_(false) {
}
void Profiler::Engage() {
if (engaged_) return;
engaged_ = true;
// TODO(mnaganov): This is actually "Chromium" mode. Flags need to be revised.
// http://code.google.com/p/v8/issues/detail?id=487
if (!FLAG_prof_lazy) {
OS::LogSharedLibraryAddresses();
}
// Start thread processing the profiler buffer.
running_ = true;
Start();
// Register to get ticks.
Logger::ticker_->SetProfiler(this);
Logger::ProfilerBeginEvent();
Logger::LogAliases();
}
void Profiler::Disengage() {
if (!engaged_) return;
// 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;
// Reset 'paused_' flag, otherwise semaphore may not be signalled.
resume();
Insert(&sample);
Join();
LOG(UncheckedStringEvent("profiler", "end"));
}
void Profiler::Run() {
TickSample sample;
bool overflow = Remove(&sample);
while (running_) {
LOG(TickEvent(&sample, overflow));
overflow = Remove(&sample);
}
}
//
// Logger class implementation.
//
Ticker* Logger::ticker_ = NULL;
Profiler* Logger::profiler_ = NULL;
SlidingStateWindow* Logger::sliding_state_window_ = NULL;
const char** Logger::log_events_ = NULL;
CompressionHelper* Logger::compression_helper_ = NULL;
int Logger::logging_nesting_ = 0;
int Logger::cpu_profiler_nesting_ = 0;
int Logger::heap_profiler_nesting_ = 0;
#define DECLARE_LONG_EVENT(ignore1, long_name, ignore2) long_name,
const char* kLongLogEventsNames[Logger::NUMBER_OF_LOG_EVENTS] = {
LOG_EVENTS_AND_TAGS_LIST(DECLARE_LONG_EVENT)
};
#undef DECLARE_LONG_EVENT
#define DECLARE_SHORT_EVENT(ignore1, ignore2, short_name) short_name,
const char* kCompressedLogEventsNames[Logger::NUMBER_OF_LOG_EVENTS] = {
LOG_EVENTS_AND_TAGS_LIST(DECLARE_SHORT_EVENT)
};
#undef DECLARE_SHORT_EVENT
void Logger::ProfilerBeginEvent() {
if (!Log::IsEnabled()) return;
LogMessageBuilder msg;
msg.Append("profiler,\"begin\",%d\n", kSamplingIntervalMs);
if (FLAG_compress_log) {
msg.Append("profiler,\"compression\",%d\n", kCompressionWindowSize);
}
msg.WriteToLogFile();
}
void Logger::LogAliases() {
if (!Log::IsEnabled() || !FLAG_compress_log) return;
LogMessageBuilder msg;
for (int i = 0; i < NUMBER_OF_LOG_EVENTS; ++i) {
msg.Append("alias,%s,%s\n",
kCompressedLogEventsNames[i], kLongLogEventsNames[i]);
}
msg.WriteToLogFile();
}
#endif // ENABLE_LOGGING_AND_PROFILING
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 (!Log::IsEnabled()) 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 (FLAG_log) UncheckedIntEvent(name, value);
#endif
}
#ifdef ENABLE_LOGGING_AND_PROFILING
void Logger::UncheckedIntEvent(const char* name, int value) {
if (!Log::IsEnabled()) 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 (!Log::IsEnabled() || !FLAG_log_handles) return;
LogMessageBuilder msg;
msg.Append("%s,0x%" V8PRIxPTR "\n", name, 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 log is enabled and that
// FLAG_log_api is true.
void Logger::ApiEvent(const char* format, ...) {
ASSERT(Log::IsEnabled() && FLAG_log_api);
LogMessageBuilder msg;
va_list ap;
va_start(ap, format);
msg.AppendVA(format, ap);
va_end(ap);
msg.WriteToLogFile();
}
#endif
void Logger::ApiNamedSecurityCheck(Object* key) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !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,
uintptr_t start,
uintptr_t end) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_prof) return;
LogMessageBuilder msg;
msg.Append("shared-library,\"%s\",0x%08" V8PRIxPTR ",0x%08" V8PRIxPTR "\n",
library_path,
start,
end);
msg.WriteToLogFile();
#endif
}
void Logger::SharedLibraryEvent(const wchar_t* library_path,
uintptr_t start,
uintptr_t end) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_prof) return;
LogMessageBuilder msg;
msg.Append("shared-library,\"%ls\",0x%08" V8PRIxPTR ",0x%08" V8PRIxPTR "\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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !FLAG_log) return;
LogMessageBuilder msg;
msg.Append("new,%s,0x%" V8PRIxPTR ",%u\n", name, object,
static_cast<unsigned int>(size));
msg.WriteToLogFile();
#endif
}
void Logger::DeleteEvent(const char* name, void* object) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log) return;
LogMessageBuilder msg;
msg.Append("delete,%s,0x%" V8PRIxPTR "\n", name, object);
msg.WriteToLogFile();
#endif
}
#ifdef ENABLE_LOGGING_AND_PROFILING
// A class that contains all common code dealing with record compression.
class CompressionHelper {
public:
explicit CompressionHelper(int window_size)
: compressor_(window_size), repeat_count_(0) { }
// Handles storing message in compressor, retrieving the previous one and
// prefixing it with repeat count, if needed.
// Returns true if message needs to be written to log.
bool HandleMessage(LogMessageBuilder* msg) {
if (!msg->StoreInCompressor(&compressor_)) {
// Current message repeats the previous one, don't write it.
++repeat_count_;
return false;
}
if (repeat_count_ == 0) {
return msg->RetrieveCompressedPrevious(&compressor_);
}
OS::SNPrintF(prefix_, "%s,%d,",
Logger::log_events_[Logger::REPEAT_META_EVENT],
repeat_count_ + 1);
repeat_count_ = 0;
return msg->RetrieveCompressedPrevious(&compressor_, prefix_.start());
}
private:
LogRecordCompressor compressor_;
int repeat_count_;
EmbeddedVector<char, 20> prefix_;
};
#endif // ENABLE_LOGGING_AND_PROFILING
#ifdef ENABLE_LOGGING_AND_PROFILING
void Logger::CallbackEventInternal(const char* prefix, const char* name,
Address entry_point) {
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,%s,",
log_events_[CODE_CREATION_EVENT], log_events_[CALLBACK_TAG]);
msg.AppendAddress(entry_point);
msg.Append(",1,\"%s%s\"", prefix, name);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
}
#endif
void Logger::CallbackEvent(String* name, Address entry_point) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
SmartPointer<char> str =
name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
CallbackEventInternal("", *str, entry_point);
#endif
}
void Logger::GetterCallbackEvent(String* name, Address entry_point) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
SmartPointer<char> str =
name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
CallbackEventInternal("get ", *str, entry_point);
#endif
}
void Logger::SetterCallbackEvent(String* name, Address entry_point) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
SmartPointer<char> str =
name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
CallbackEventInternal("set ", *str, entry_point);
#endif
}
void Logger::CodeCreateEvent(LogEventsAndTags tag,
Code* code,
const char* comment) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,%s,", log_events_[CODE_CREATION_EVENT], log_events_[tag]);
msg.AppendAddress(code->address());
msg.Append(",%d,\"", code->ExecutableSize());
for (const char* p = comment; *p != '\0'; p++) {
if (*p == '"') {
msg.Append('\\');
}
msg.Append(*p);
}
msg.Append('"');
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::CodeCreateEvent(LogEventsAndTags tag, Code* code, String* name) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
SmartPointer<char> str =
name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL);
msg.Append("%s,%s,", log_events_[CODE_CREATION_EVENT], log_events_[tag]);
msg.AppendAddress(code->address());
msg.Append(",%d,\"%s\"", code->ExecutableSize(), *str);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::CodeCreateEvent(LogEventsAndTags tag,
Code* code, String* name,
String* source, int line) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !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("%s,%s,", log_events_[CODE_CREATION_EVENT], log_events_[tag]);
msg.AppendAddress(code->address());
msg.Append(",%d,\"%s %s:%d\"",
code->ExecutableSize(), *str, *sourcestr, line);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::CodeCreateEvent(LogEventsAndTags tag, Code* code, int args_count) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,%s,", log_events_[CODE_CREATION_EVENT], log_events_[tag]);
msg.AppendAddress(code->address());
msg.Append(",%d,\"args_count: %d\"", code->ExecutableSize(), args_count);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::RegExpCodeCreateEvent(Code* code, String* source) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,%s,",
log_events_[CODE_CREATION_EVENT], log_events_[REG_EXP_TAG]);
msg.AppendAddress(code->address());
msg.Append(",%d,\"", code->ExecutableSize());
msg.AppendDetailed(source, false);
msg.Append('\"');
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::CodeMoveEvent(Address from, Address to) {
#ifdef ENABLE_LOGGING_AND_PROFILING
MoveEventInternal(CODE_MOVE_EVENT, from, to);
#endif
}
void Logger::CodeDeleteEvent(Address from) {
#ifdef ENABLE_LOGGING_AND_PROFILING
DeleteEventInternal(CODE_DELETE_EVENT, from);
#endif
}
void Logger::SnapshotPositionEvent(Address addr, int pos) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_snapshot_positions) return;
LogMessageBuilder msg;
msg.Append("%s,", log_events_[SNAPSHOT_POSITION_EVENT]);
msg.AppendAddress(addr);
msg.Append(",%d", pos);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::FunctionCreateEvent(JSFunction* function) {
#ifdef ENABLE_LOGGING_AND_PROFILING
static Address prev_code = NULL;
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,", log_events_[FUNCTION_CREATION_EVENT]);
msg.AppendAddress(function->address());
msg.Append(',');
msg.AppendAddress(function->code()->address(), prev_code);
prev_code = function->code()->address();
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
#endif
}
void Logger::FunctionMoveEvent(Address from, Address to) {
#ifdef ENABLE_LOGGING_AND_PROFILING
MoveEventInternal(FUNCTION_MOVE_EVENT, from, to);
#endif
}
void Logger::FunctionDeleteEvent(Address from) {
#ifdef ENABLE_LOGGING_AND_PROFILING
DeleteEventInternal(FUNCTION_DELETE_EVENT, from);
#endif
}
#ifdef ENABLE_LOGGING_AND_PROFILING
void Logger::MoveEventInternal(LogEventsAndTags event,
Address from,
Address to) {
static Address prev_to_ = NULL;
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,", log_events_[event]);
msg.AppendAddress(from);
msg.Append(',');
msg.AppendAddress(to, prev_to_);
prev_to_ = to;
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
}
#endif
#ifdef ENABLE_LOGGING_AND_PROFILING
void Logger::DeleteEventInternal(LogEventsAndTags event, Address from) {
if (!Log::IsEnabled() || !FLAG_log_code) return;
LogMessageBuilder msg;
msg.Append("%s,", log_events_[event]);
msg.AppendAddress(from);
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
}
#endif
void Logger::ResourceEvent(const char* name, const char* tag) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !FLAG_log_suspect) return;
LogMessageBuilder msg;
String* class_name = obj->IsJSObject()
? JSObject::cast(obj)->class_name()
: Heap::empty_string();
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 (!Log::IsEnabled() || !FLAG_log_gc) return;
LogMessageBuilder msg;
// 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();
#endif
}
void Logger::HeapSampleStats(const char* space, const char* kind,
int capacity, int used) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_gc) return;
LogMessageBuilder msg;
msg.Append("heap-sample-stats,\"%s\",\"%s\",%d,%d\n",
space, kind, capacity, used);
msg.WriteToLogFile();
#endif
}
void Logger::HeapSampleEndEvent(const char* space, const char* kind) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !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 (!Log::IsEnabled() || !FLAG_log_gc) return;
LogMessageBuilder msg;
msg.Append("heap-sample-item,%s,%d,%d\n", type, number, bytes);
msg.WriteToLogFile();
#endif
}
void Logger::HeapSampleJSConstructorEvent(const char* constructor,
int number, int bytes) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_gc) return;
LogMessageBuilder msg;
msg.Append("heap-js-cons-item,%s,%d,%d\n", constructor, number, bytes);
msg.WriteToLogFile();
#endif
}
void Logger::HeapSampleJSRetainersEvent(
const char* constructor, const char* event) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_gc) return;
// Event starts with comma, so we don't have it in the format string.
static const char* event_text = "heap-js-ret-item,%s";
// We take placeholder strings into account, but it's OK to be conservative.
static const int event_text_len = StrLength(event_text);
const int cons_len = StrLength(constructor);
const int event_len = StrLength(event);
int pos = 0;
// Retainer lists can be long. We may need to split them into multiple events.
do {
LogMessageBuilder msg;
msg.Append(event_text, constructor);
int to_write = event_len - pos;
if (to_write > Log::kMessageBufferSize - (cons_len + event_text_len)) {
int cut_pos = pos + Log::kMessageBufferSize - (cons_len + event_text_len);
ASSERT(cut_pos < event_len);
while (cut_pos > pos && event[cut_pos] != ',') --cut_pos;
if (event[cut_pos] != ',') {
// Crash in debug mode, skip in release mode.
ASSERT(false);
return;
}
// Append a piece of event that fits, without trailing comma.
msg.AppendStringPart(event + pos, cut_pos - pos);
// Start next piece with comma.
pos = cut_pos;
} else {
msg.Append("%s", event + pos);
pos += event_len;
}
msg.Append('\n');
msg.WriteToLogFile();
} while (pos < event_len);
#endif
}
void Logger::HeapSampleJSProducerEvent(const char* constructor,
Address* stack) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !FLAG_log_gc) return;
LogMessageBuilder msg;
msg.Append("heap-js-prod-item,%s", constructor);
while (*stack != NULL) {
msg.Append(",0x%" V8PRIxPTR, *stack++);
}
msg.Append("\n");
msg.WriteToLogFile();
#endif
}
void Logger::DebugTag(const char* call_site_tag) {
#ifdef ENABLE_LOGGING_AND_PROFILING
if (!Log::IsEnabled() || !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 (!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;
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 (!Log::IsEnabled() || !FLAG_prof) return;
static Address prev_sp = NULL;
static Address prev_function = NULL;
LogMessageBuilder msg;
msg.Append("%s,", log_events_[TICK_EVENT]);
Address prev_addr = sample->pc;
msg.AppendAddress(prev_addr);
msg.Append(',');
msg.AppendAddress(sample->sp, prev_sp);
prev_sp = sample->sp;
msg.Append(',');
msg.AppendAddress(sample->function, prev_function);
prev_function = sample->function;
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], prev_addr);
prev_addr = sample->stack[i];
}
if (FLAG_compress_log) {
ASSERT(compression_helper_ != NULL);
if (!compression_helper_->HandleMessage(&msg)) return;
}
msg.Append('\n');
msg.WriteToLogFile();
}
int Logger::GetActiveProfilerModules() {
int result = PROFILER_MODULE_NONE;
if (profiler_ != NULL && !profiler_->paused()) {
result |= PROFILER_MODULE_CPU;
}
if (FLAG_log_gc) {
result |= PROFILER_MODULE_HEAP_STATS | PROFILER_MODULE_JS_CONSTRUCTORS;
}
return result;
}
void Logger::PauseProfiler(int flags, int tag) {
if (!Log::IsEnabled()) return;
if (profiler_ != NULL && (flags & PROFILER_MODULE_CPU)) {
// It is OK to have negative nesting.
if (--cpu_profiler_nesting_ == 0) {
profiler_->pause();
if (FLAG_prof_lazy) {
if (!FLAG_sliding_state_window) ticker_->Stop();
FLAG_log_code = false;
// Must be the same message as Log::kDynamicBufferSeal.
LOG(UncheckedStringEvent("profiler", "pause"));
}
--logging_nesting_;
}
}
if (flags &
(PROFILER_MODULE_HEAP_STATS | PROFILER_MODULE_JS_CONSTRUCTORS)) {
if (--heap_profiler_nesting_ == 0) {
FLAG_log_gc = false;
--logging_nesting_;
}
}
if (tag != 0) {
UncheckedIntEvent("close-tag", tag);
}
}
void Logger::ResumeProfiler(int flags, int tag) {
if (!Log::IsEnabled()) return;
if (tag != 0) {
UncheckedIntEvent("open-tag", tag);
}
if (profiler_ != NULL && (flags & PROFILER_MODULE_CPU)) {
if (cpu_profiler_nesting_++ == 0) {
++logging_nesting_;
if (FLAG_prof_lazy) {
profiler_->Engage();
LOG(UncheckedStringEvent("profiler", "resume"));
FLAG_log_code = true;
LogCompiledFunctions();
LogFunctionObjects();
LogAccessorCallbacks();
if (!FLAG_sliding_state_window) ticker_->Start();
}
profiler_->resume();
}
}
if (flags &
(PROFILER_MODULE_HEAP_STATS | PROFILER_MODULE_JS_CONSTRUCTORS)) {
if (heap_profiler_nesting_++ == 0) {
++logging_nesting_;
FLAG_log_gc = true;
}
}
}
// This function can be called when Log's mutex is acquired,
// either from main or Profiler's thread.
void Logger::StopLoggingAndProfiling() {
Log::stop();
PauseProfiler(PROFILER_MODULE_CPU, 0);
}
bool Logger::IsProfilerSamplerActive() {
return ticker_->IsActive();
}
int Logger::GetLogLines(int from_pos, char* dest_buf, int max_size) {
return Log::GetLogLines(from_pos, dest_buf, max_size);
}
static int EnumerateCompiledFunctions(Handle<SharedFunctionInfo>* sfis) {
AssertNoAllocation no_alloc;
int compiled_funcs_count = 0;
HeapIterator iterator;
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);
++compiled_funcs_count;
}
}
return compiled_funcs_count;
}
void Logger::LogCodeObject(Object* object) {
if (FLAG_log_code) {
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:
return; // We log this later using LogCompiledFunctions.
case Code::BINARY_OP_IC:
// fall through
case Code::STUB:
description = CodeStub::MajorName(code_object->major_key(), true);
if (description == NULL)
description = "A stub from the snapshot";
tag = Logger::STUB_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;
}
PROFILE(CodeCreateEvent(tag, code_object, description));
}
}
void Logger::LogCodeObjects() {
AssertNoAllocation no_alloc;
HeapIterator iterator;
for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
if (obj->IsCode()) LogCodeObject(obj);
}
}
void Logger::LogCompiledFunctions() {
HandleScope scope;
const int compiled_funcs_count = EnumerateCompiledFunctions(NULL);
ScopedVector< Handle<SharedFunctionInfo> > sfis(compiled_funcs_count);
EnumerateCompiledFunctions(sfis.start());
// During iteration, there can be heap allocation due to
// GetScriptLineNumber call.
for (int i = 0; i < compiled_funcs_count; ++i) {
Handle<SharedFunctionInfo> shared = sfis[i];
Handle<String> name(String::cast(shared->name()));
Handle<String> func_name(name->length() > 0 ?
*name : shared->inferred_name());
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(CodeCreateEvent(
Logger::ToNativeByScript(Logger::LAZY_COMPILE_TAG, *script),
shared->code(), *func_name,
*script_name, line_num + 1));
} else {
// Can't distinguish eval and script here, so always use Script.
PROFILE(CodeCreateEvent(
Logger::ToNativeByScript(Logger::SCRIPT_TAG, *script),
shared->code(), *script_name));
}
} else {
PROFILE(CodeCreateEvent(
Logger::ToNativeByScript(Logger::LAZY_COMPILE_TAG, *script),
shared->code(), *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(CallbackEvent(*func_name, entry_point));
}
} else {
PROFILE(CodeCreateEvent(
Logger::LAZY_COMPILE_TAG, shared->code(), *func_name));
}
}
}
void Logger::LogFunctionObjects() {
AssertNoAllocation no_alloc;
HeapIterator iterator;
for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
if (!obj->IsJSFunction()) continue;
JSFunction* jsf = JSFunction::cast(obj);
if (!jsf->is_compiled()) continue;
PROFILE(FunctionCreateEvent(jsf));
}
}
void Logger::LogAccessorCallbacks() {
AssertNoAllocation no_alloc;
HeapIterator iterator;
for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
if (!obj->IsAccessorInfo()) continue;
AccessorInfo* ai = AccessorInfo::cast(obj);
if (!ai->name()->IsString()) continue;
String* name = String::cast(ai->name());
Address getter_entry = v8::ToCData<Address>(ai->getter());
if (getter_entry != 0) {
PROFILE(GetterCallbackEvent(name, getter_entry));
}
Address setter_entry = v8::ToCData<Address>(ai->setter());
if (setter_entry != 0) {
PROFILE(SetterCallbackEvent(name, setter_entry));
}
}
}
#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;
// --prof_lazy controls --log-code, implies --noprof_auto.
if (FLAG_prof_lazy) {
FLAG_log_code = false;
FLAG_prof_auto = false;
}
bool start_logging = 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;
bool open_log_file = start_logging || FLAG_prof_lazy;
// If we're logging anything, we need to open the log file.
if (open_log_file) {
if (strcmp(FLAG_logfile, "-") == 0) {
Log::OpenStdout();
} else if (strcmp(FLAG_logfile, "*") == 0) {
Log::OpenMemoryBuffer();
} 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.
double time = OS::TimeCurrentMillis();
stream.Add("%.0f", FmtElm(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();
Log::OpenFile(*expanded);
} else {
Log::OpenFile(FLAG_logfile);
}
}
ASSERT(VMState::is_outermost_external());
ticker_ = new Ticker(kSamplingIntervalMs);
if (FLAG_sliding_state_window && sliding_state_window_ == NULL) {
sliding_state_window_ = new SlidingStateWindow();
}
log_events_ = FLAG_compress_log ?
kCompressedLogEventsNames : kLongLogEventsNames;
if (FLAG_compress_log) {
compression_helper_ = new CompressionHelper(kCompressionWindowSize);
}
if (start_logging) {
logging_nesting_ = 1;
}
if (FLAG_prof) {
profiler_ = new Profiler();
if (!FLAG_prof_auto) {
profiler_->pause();
} else {
logging_nesting_ = 1;
}
if (!FLAG_prof_lazy) {
profiler_->Engage();
}
}
LogMessageBuilder::set_write_failure_handler(StopLoggingAndProfiling);
return true;
#else
return false;
#endif
}
void Logger::TearDown() {
#ifdef ENABLE_LOGGING_AND_PROFILING
LogMessageBuilder::set_write_failure_handler(NULL);
// Stop the profiler before closing the file.
if (profiler_ != NULL) {
profiler_->Disengage();
delete profiler_;
profiler_ = NULL;
}
delete compression_helper_;
compression_helper_ = NULL;
delete sliding_state_window_;
sliding_state_window_ = NULL;
delete ticker_;
ticker_ = NULL;
Log::Close();
#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
}
} } // namespace v8::internal