Revert "Remove support for MSVC"

sky/engine/wtf/Atomics.h

 /*
  * Copyright (C) 2007, 2008, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 17 matching lines @@
  */
 
 #ifndef Atomics_h
 #define Atomics_h
 
 #include "wtf/Assertions.h"
 #include "wtf/CPU.h"
 
 #include <stdint.h>
 
+#if COMPILER(MSVC)
+#include <windows.h>
+#endif
+
 #if defined(THREAD_SANITIZER)
 #include <sanitizer/tsan_interface_atomic.h>
 #endif
 
 namespace WTF {
 
+#if COMPILER(MSVC)
+
+// atomicAdd returns the result of the addition.
+ALWAYS_INLINE int atomicAdd(int volatile* addend, int increment)
+{
+    return InterlockedExchangeAdd(reinterpret_cast<long volatile*>(addend), static_cast<long>(increment)) + increment;
+}
+
+// atomicSubtract returns the result of the subtraction.
+ALWAYS_INLINE int atomicSubtract(int volatile* addend, int decrement)
+{
+    return InterlockedExchangeAdd(reinterpret_cast<long volatile*>(addend), static_cast<long>(-decrement)) - decrement;
+}
+
+ALWAYS_INLINE int atomicIncrement(int volatile* addend) { return InterlockedIncrement(reinterpret_cast<long volatile*>(addend)); }
+ALWAYS_INLINE int atomicDecrement(int volatile* addend) { return InterlockedDecrement(reinterpret_cast<long volatile*>(addend)); }
+
+ALWAYS_INLINE int64_t atomicIncrement(int64_t volatile* addend) { return InterlockedIncrement64(reinterpret_cast<long long volatile*>(addend)); }
+ALWAYS_INLINE int64_t atomicDecrement(int64_t volatile* addend) { return InterlockedDecrement64(reinterpret_cast<long long volatile*>(addend)); }
+
+ALWAYS_INLINE int atomicTestAndSetToOne(int volatile* ptr)
+{
+    int ret = InterlockedExchange(reinterpret_cast<long volatile*>(ptr), 1);
+    ASSERT(!ret || ret == 1);
+    return ret;
+}
+
+ALWAYS_INLINE void atomicSetOneToZero(int volatile* ptr)
+{
+    ASSERT(*ptr == 1);
+    InterlockedExchange(reinterpret_cast<long volatile*>(ptr), 0);
+}
+
+#else
+
 // atomicAdd returns the result of the addition.
 ALWAYS_INLINE int atomicAdd(int volatile* addend, int increment) { return __sync_add_and_fetch(addend, increment); }
 // atomicSubtract returns the result of the subtraction.
 ALWAYS_INLINE int atomicSubtract(int volatile* addend, int decrement) { return __sync_sub_and_fetch(addend, decrement); }
 
 ALWAYS_INLINE int atomicIncrement(int volatile* addend) { return atomicAdd(addend, 1); }
 ALWAYS_INLINE int atomicDecrement(int volatile* addend) { return atomicSubtract(addend, 1); }
 
 ALWAYS_INLINE int64_t atomicIncrement(int64_t volatile* addend) { return __sync_add_and_fetch(addend, 1); }
 ALWAYS_INLINE int64_t atomicDecrement(int64_t volatile* addend) { return __sync_sub_and_fetch(addend, 1); }
 
 ALWAYS_INLINE int atomicTestAndSetToOne(int volatile* ptr)
 {
     int ret = __sync_lock_test_and_set(ptr, 1);
     ASSERT(!ret || ret == 1);
     return ret;
 }
 
 ALWAYS_INLINE void atomicSetOneToZero(int volatile* ptr)
 {
     ASSERT(*ptr == 1);
     __sync_lock_release(ptr);
 }
+#endif
 
 #if defined(THREAD_SANITIZER)
 ALWAYS_INLINE void releaseStore(volatile int* ptr, int value)
 {
     __tsan_atomic32_store(ptr, value, __tsan_memory_order_release);
 }
 
 ALWAYS_INLINE int acquireLoad(volatile const int* ptr)
 {
     return __tsan_atomic32_load(ptr, __tsan_memory_order_acquire);
 }
 
 ALWAYS_INLINE void releaseStore(volatile unsigned* ptr, unsigned value)
 {
     __tsan_atomic32_store(reinterpret_cast<volatile int*>(ptr), static_cast<int>(value), __tsan_memory_order_release);
 }
 
 ALWAYS_INLINE unsigned acquireLoad(volatile const unsigned* ptr)
 {
     return static_cast<unsigned>(__tsan_atomic32_load(reinterpret_cast<volatile const int*>(ptr), __tsan_memory_order_acquire));
 }
 #else
 
 #if CPU(X86) || CPU(X86_64)
 // Only compiler barrier is needed.
+#if COMPILER(MSVC)
+// Starting from Visual Studio 2005 compiler guarantees acquire and release
+// semantics for operations on volatile variables. See MSDN entry for
+// MemoryBarrier macro.
+#define MEMORY_BARRIER()
+#else
 #define MEMORY_BARRIER() __asm__ __volatile__("" : : : "memory")
+#endif
 #elif CPU(ARM) && (OS(LINUX) || OS(ANDROID))
 // On ARM __sync_synchronize generates dmb which is very expensive on single
 // core devices which don't actually need it. Avoid the cost by calling into
 // kuser_memory_barrier helper.
 inline void memoryBarrier()
 {
     // Note: This is a function call, which is also an implicit compiler barrier.
     typedef void (*KernelMemoryBarrierFunc)();
     ((KernelMemoryBarrierFunc)0xffff0fa0)();
 }
@@ skipping 38 matching lines @@
 using WTF::atomicAdd;
 using WTF::atomicSubtract;
 using WTF::atomicDecrement;
 using WTF::atomicIncrement;
 using WTF::atomicTestAndSetToOne;
 using WTF::atomicSetOneToZero;
 using WTF::acquireLoad;
 using WTF::releaseStore;
 
 #endif // Atomics_h