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Unified Diff: src/platform-win32.cc

Issue 21095008: Revert the latest set of platform changes. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 7 years, 5 months ago
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Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index c0f049c52d9bacbee9f286c02b0c00f9df609b64..292c24a3dace86c6500acbd6634536d0dea7ddb6 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -1705,6 +1705,46 @@ void Thread::YieldCPU() {
// ----------------------------------------------------------------------------
+// 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_); }
+
+ virtual ~Win32Mutex() { DeleteCriticalSection(&cs_); }
+
+ virtual int Lock() {
+ EnterCriticalSection(&cs_);
+ return 0;
+ }
+
+ virtual int Unlock() {
+ LeaveCriticalSection(&cs_);
+ return 0;
+ }
+
+
+ virtual bool TryLock() {
+ // Returns non-zero if critical section is entered successfully entered.
+ return TryEnterCriticalSection(&cs_);
+ }
+
+ 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
@@ -1947,7 +1987,7 @@ void OS::SetUp() {
// call this setup code within the same millisecond.
uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
srand(static_cast<unsigned int>(seed));
- limit_mutex = new Mutex;
+ limit_mutex = CreateMutex();
}
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