platform-win32.cc.svn-base

Google浏览器V8内核代码

      }
    }
    DeleteArray(symbol);

    frames_count++;
  }

  // Return the number of frames filled in.
  return frames_count;
}

// Restore warnings to previous settings.
#pragma warning(pop)


double OS::nan_value() {
  static const __int64 nanval = 0xfff8000000000000;
  return *reinterpret_cast<const double*>(&nanval);
}


int OS::ActivationFrameAlignment() {
  // No constraint on Windows.
  return 0;
}


bool VirtualMemory::IsReserved() {
  return address_ != NULL;
}


VirtualMemory::VirtualMemory(size_t size) {
  address_ = VirtualAlloc(NULL, size, MEM_RESERVE, PAGE_NOACCESS);
  size_ = size;
}


VirtualMemory::~VirtualMemory() {
  if (IsReserved()) {
    if (0 == VirtualFree(address(), 0, MEM_RELEASE)) address_ = NULL;
  }
}


bool VirtualMemory::Commit(void* address, size_t size, bool executable) {
  int prot = executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
  if (NULL == VirtualAlloc(address, size, MEM_COMMIT, prot)) {
    return false;
  }

  UpdateAllocatedSpaceLimits(address, size);
  return true;
}


bool VirtualMemory::Uncommit(void* address, size_t size) {
  ASSERT(IsReserved());
  return VirtualFree(address, size, MEM_DECOMMIT) != NULL;
}


// ----------------------------------------------------------------------------
// Win32 thread support.

// Definition of invalid thread handle and id.
static const HANDLE kNoThread = INVALID_HANDLE_VALUE;
static const DWORD kNoThreadId = 0;


class ThreadHandle::PlatformData : public Malloced {
 public:
  explicit PlatformData(ThreadHandle::Kind kind) {
    Initialize(kind);
  }

  void Initialize(ThreadHandle::Kind kind) {
    switch (kind) {
      case ThreadHandle::SELF: tid_ = GetCurrentThreadId(); break;
      case ThreadHandle::INVALID: tid_ = kNoThreadId; break;
    }
  }
  DWORD tid_;  // Win32 thread identifier.
};


// Entry point for threads. The supplied argument is a pointer to the thread
// object. The entry function dispatches to the run method in the thread
// object. It is important that this function has __stdcall calling
// convention.
static unsigned int __stdcall ThreadEntry(void* arg) {
  Thread* thread = reinterpret_cast<Thread*>(arg);
  // This is also initialized by the last parameter to _beginthreadex() but we
  // don't know which thread will run first (the original thread or the new
  // one) so we initialize it here too.
  thread->thread_handle_data()->tid_ = GetCurrentThreadId();
  thread->Run();
  return 0;
}


// Initialize thread handle to invalid handle.
ThreadHandle::ThreadHandle(ThreadHandle::Kind kind) {
  data_ = new PlatformData(kind);
}


ThreadHandle::~ThreadHandle() {
  delete data_;
}


// The thread is running if it has the same id as the current thread.
bool ThreadHandle::IsSelf() const {
  return GetCurrentThreadId() == data_->tid_;
}


// Test for invalid thread handle.
bool ThreadHandle::IsValid() const {
  return data_->tid_ != kNoThreadId;
}


void ThreadHandle::Initialize(ThreadHandle::Kind kind) {
  data_->Initialize(kind);
}


class Thread::PlatformData : public Malloced {
 public:
  explicit PlatformData(HANDLE thread) : thread_(thread) {}
  HANDLE thread_;
};


// Initialize a Win32 thread object. The thread has an invalid thread
// handle until it is started.

Thread::Thread() : ThreadHandle(ThreadHandle::INVALID) {
  data_ = new PlatformData(kNoThread);
}


// Close our own handle for the thread.
Thread::~Thread() {
  if (data_->thread_ != kNoThread) CloseHandle(data_->thread_);
  delete data_;
}


// Create a new thread. It is important to use _beginthreadex() instead of
// the Win32 function CreateThread(), because the CreateThread() does not
// initialize thread specific structures in the C runtime library.
void Thread::Start() {
  data_->thread_ = reinterpret_cast<HANDLE>(
      _beginthreadex(NULL,
                     0,
                     ThreadEntry,
                     this,
                     0,
                     reinterpret_cast<unsigned int*>(
                         &thread_handle_data()->tid_)));
  ASSERT(IsValid());
}


// Wait for thread to terminate.
void Thread::Join() {
  WaitForSingleObject(data_->thread_, INFINITE);
}


Thread::LocalStorageKey Thread::CreateThreadLocalKey() {
  DWORD result = TlsAlloc();
  ASSERT(result != TLS_OUT_OF_INDEXES);
  return static_cast<LocalStorageKey>(result);
}


void Thread::DeleteThreadLocalKey(LocalStorageKey key) {
  BOOL result = TlsFree(static_cast<DWORD>(key));
  USE(result);
  ASSERT(result);
}


void* Thread::GetThreadLocal(LocalStorageKey key) {
  return TlsGetValue(static_cast<DWORD>(key));
}


void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
  BOOL result = TlsSetValue(static_cast<DWORD>(key), value);
  USE(result);
  ASSERT(result);
}



void Thread::YieldCPU() {
  Sleep(0);
}


// ----------------------------------------------------------------------------
// Win32 mutex support.
//
// On Win32 mutexes are implemented using CRITICAL_SECTION objects. These are
// faster than Win32 Mutex objects because they are implemented using user mode
// atomic instructions. Therefore we only do ring transitions if there is lock
// contention.

class Win32Mutex : public Mutex {
 public:

  Win32Mutex() { InitializeCriticalSection(&cs_); }

  ~Win32Mutex() { DeleteCriticalSection(&cs_); }

  int Lock() {
    EnterCriticalSection(&cs_);
    return 0;
  }

  int Unlock() {
    LeaveCriticalSection(&cs_);
    return 0;
  }

 private:
  CRITICAL_SECTION cs_;  // Critical section used for mutex
};


Mutex* OS::CreateMutex() {
  return new Win32Mutex();
}


// ----------------------------------------------------------------------------
// Win32 semaphore support.
//
// On Win32 semaphores are implemented using Win32 Semaphore objects. The
// semaphores are anonymous. Also, the semaphores are initialized to have
// no upper limit on count.


class Win32Semaphore : public Semaphore {
 public:
  explicit Win32Semaphore(int count) {
    sem = ::CreateSemaphoreA(NULL, count, 0x7fffffff, NULL);
  }

  ~Win32Semaphore() {
    CloseHandle(sem);
  }

  void Wait() {
    WaitForSingleObject(sem, INFINITE);
  }

  void Signal() {
    LONG dummy;
    ReleaseSemaphore(sem, 1, &dummy);
  }

 private:
  HANDLE sem;
};


Semaphore* OS::CreateSemaphore(int count) {
  return new Win32Semaphore(count);
}

#ifdef ENABLE_LOGGING_AND_PROFILING

// ----------------------------------------------------------------------------
// Win32 profiler support.
//
// On win32 we use a sampler thread with high priority to sample the program
// counter for the profiled thread.

class Sampler::PlatformData : public Malloced {
 public:
  explicit PlatformData(Sampler* sampler) {
    sampler_ = sampler;
    sampler_thread_ = INVALID_HANDLE_VALUE;
    profiled_thread_ = INVALID_HANDLE_VALUE;
  }

  Sampler* sampler_;
  HANDLE sampler_thread_;
  HANDLE profiled_thread_;

  // Sampler thread handler.
  void Runner() {
    // Context used for sampling the register state of the profiled thread.
    CONTEXT context;
    memset(&context, 0, sizeof(context));
    // Loop until the sampler is disengaged.
    while (sampler_->IsActive()) {
      TickSample sample;

      // If profiling, we record the pc and sp of the profiled thread.
      if (sampler_->IsProfiling()) {
        // Pause the profiled thread and get its context.
        SuspendThread(profiled_thread_);
        context.ContextFlags = CONTEXT_FULL;
        GetThreadContext(profiled_thread_, &context);
        ResumeThread(profiled_thread_);
        // Invoke tick handler with program counter and stack pointer.
        sample.pc = context.Eip;
        sample.sp = context.Esp;
      }

      // We always sample the VM state.
      sample.state = Logger::state();
      sampler_->Tick(&sample);

      // Wait until next sampling.
      Sleep(sampler_->interval_);
    }
  }
};


// Entry point for sampler thread.
static unsigned int __stdcall SamplerEntry(void* arg) {
  Sampler::PlatformData* data =
      reinterpret_cast<Sampler::PlatformData*>(arg);
  data->Runner();
  return 0;
}


// Initialize a profile sampler.
Sampler::Sampler(int interval, bool profiling)
    : interval_(interval), profiling_(profiling), active_(false) {
  data_ = new PlatformData(this);
}


Sampler::~Sampler() {
  delete data_;
}


// Start profiling.
void Sampler::Start() {
  // If we are profiling, we need to be able to access the calling
  // thread.
  if (IsProfiling()) {
    // Get a handle to the calling thread. This is the thread that we are
    // going to profile. We need to duplicate the handle because we are
    // going to use it in the sampler thread. using GetThreadHandle() will
    // not work in this case.
    BOOL ok = DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
                              GetCurrentProcess(), &data_->profiled_thread_,
                              THREAD_GET_CONTEXT | THREAD_SUSPEND_RESUME |
                              THREAD_QUERY_INFORMATION, FALSE, 0);
    if (!ok) return;
  }

  // Start sampler thread.
  unsigned int tid;
  active_ = true;
  data_->sampler_thread_ = reinterpret_cast<HANDLE>(
      _beginthreadex(NULL, 0, SamplerEntry, data_, 0, &tid));
  // Set thread to high priority to increase sampling accuracy.
  SetThreadPriority(data_->sampler_thread_, THREAD_PRIORITY_TIME_CRITICAL);
}


// Stop profiling.
void Sampler::Stop() {
  // Seting active to false triggers termination of the sampler
  // thread.
  active_ = false;

  // Wait for sampler thread to terminate.
  WaitForSingleObject(data_->sampler_thread_, INFINITE);

  // Release the thread handles
  CloseHandle(data_->sampler_thread_);
  CloseHandle(data_->profiled_thread_);
}


#endif  // ENABLE_LOGGING_AND_PROFILING

} }  // namespace v8::internal