Implement correct OS and CC detection.

src/platform.h

 // Copyright 2012 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
@@ skipping 26 matching lines @@
 // the platform dependent classes could have been implemented using abstract
 // superclasses with virtual methods and having specializations for each
 // platform. This design was rejected because it was more complicated and
 // slower. It would require factory methods for selecting the right
 // implementation and the overhead of virtual methods for performance
 // sensitive like mutex locking/unlocking.
 
 #ifndef V8_PLATFORM_H_
 #define V8_PLATFORM_H_
 
+#include <stdarg.h>
+
 #ifdef __sun
 # ifndef signbit
 namespace std {
 int signbit(double x);
 }
 # endif
 #endif
 
-// GCC specific stuff
-#ifdef __GNUC__
-
-// Needed for va_list on at least MinGW and Android.
-#include <stdarg.h>
-
-#define __GNUC_VERSION__ (__GNUC__ * 10000 + __GNUC_MINOR__ * 100)
-
-#endif  // __GNUC__
-
 
 // Windows specific stuff.
 #ifdef WIN32
 
 // Microsoft Visual C++ specific stuff.
 #ifdef _MSC_VER
 
 #include "win32-headers.h"
 #include "win32-math.h"
 
@@ skipping 50 matching lines @@
 void lazily_initialize_fast_exp();
 
 // Forward declarations.
 class Socket;
 
 // ----------------------------------------------------------------------------
 // Fast TLS support
 
 #ifndef V8_NO_FAST_TLS
 
-#if defined(_MSC_VER) && V8_HOST_ARCH_IA32
+#if V8_CC_MSVC && V8_HOST_ARCH_IA32
 
 #define V8_FAST_TLS_SUPPORTED 1
 
 INLINE(intptr_t InternalGetExistingThreadLocal(intptr_t index));
 
 inline intptr_t InternalGetExistingThreadLocal(intptr_t index) {
   const intptr_t kTibInlineTlsOffset = 0xE10;
   const intptr_t kTibExtraTlsOffset = 0xF94;
   const intptr_t kMaxInlineSlots = 64;
   const intptr_t kMaxSlots = kMaxInlineSlots + 1024;
   ASSERT(0 <= index && index < kMaxSlots);
   if (index < kMaxInlineSlots) {
     return static_cast<intptr_t>(__readfsdword(kTibInlineTlsOffset +
                                                kPointerSize * index));
   }
   intptr_t extra = static_cast<intptr_t>(__readfsdword(kTibExtraTlsOffset));
   ASSERT(extra != 0);
   return *reinterpret_cast<intptr_t*>(extra +
                                       kPointerSize * (index - kMaxInlineSlots));
 }
 
-#elif defined(__APPLE__) && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
+#elif V8_OS_DARWIN && (V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64)
 
 #define V8_FAST_TLS_SUPPORTED 1
 
 extern intptr_t kMacTlsBaseOffset;
 
 INLINE(intptr_t InternalGetExistingThreadLocal(intptr_t index));
 
 inline intptr_t InternalGetExistingThreadLocal(intptr_t index) {
   intptr_t result;
 #if V8_HOST_ARCH_IA32
@@ skipping 210 matching lines @@
   // EABI is used.
   static bool ArmUsingHardFloat();
 
   // Support runtime detection of FPU on MIPS CPUs.
   static bool MipsCpuHasFeature(CpuFeature feature);
 
   // Returns the activation frame alignment constraint or zero if
   // the platform doesn't care. Guaranteed to be a power of two.
   static int ActivationFrameAlignment();
 
-#if defined(V8_TARGET_ARCH_IA32)
+#if V8_TARGET_ARCH_IA32
   // Limit below which the extra overhead of the MemCopy function is likely
   // to outweigh the benefits of faster copying.
   static const int kMinComplexMemCopy = 64;
 
   // Copy memory area. No restrictions.
   static void MemMove(void* dest, const void* src, size_t size);
   typedef void (*MemMoveFunction)(void* dest, const void* src, size_t size);
 
   // Keep the distinction of "move" vs. "copy" for the benefit of other
   // architectures.
   static void MemCopy(void* dest, const void* src, size_t size) {
     MemMove(dest, src, size);
   }
-#elif defined(V8_HOST_ARCH_ARM)
+#elif V8_HOST_ARCH_ARM
   typedef void (*MemCopyUint8Function)(uint8_t* dest,
                                        const uint8_t* src,
                                        size_t size);
   static MemCopyUint8Function memcopy_uint8_function;
   static void MemCopyUint8Wrapper(uint8_t* dest,
                                   const uint8_t* src,
                                   size_t chars) {
     memcpy(dest, src, chars);
   }
   // For values < 16, the assembler function is slower than the inlined C code.
@@ skipping 404 matching lines @@
   static uint16_t HToN(uint16_t value);
   static uint16_t NToH(uint16_t value);
   static uint32_t HToN(uint32_t value);
   static uint32_t NToH(uint32_t value);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_