Sync OS::GetCurrentThreadId with chromium's/blink's implementation

src/base/platform/platform-posix.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Platform-specific code for POSIX goes here. This is not a platform on its
 // own, but contains the parts which are the same across the POSIX platforms
 // Linux, MacOS, FreeBSD, OpenBSD, NetBSD and QNX.
 
 #include <errno.h>
 #include <limits.h>
@@ skipping 235 matching lines @@
   return NAN;
 }
 
 
 int OS::GetCurrentProcessId() {
   return static_cast<int>(getpid());
 }
 
 
 int OS::GetCurrentThreadId() {
-#if defined(ANDROID)
+#if V8_OS_MACOSX
+  return static_cast<int>(pthread_mac_thread_np(pthread_self()));
+#elif V8_OS_LINUX
   return static_cast<int>(syscall(__NR_gettid));
-#elif defined(SYS_gettid)
-  return static_cast<int>(syscall(SYS_gettid));
+#elif V8_OS_ANDROID
+  return static_cast<int>(gettid());
 #else
-  // PNaCL doesn't have a way to get an integral thread ID, but it doesn't
-  // really matter, because we only need it in PerfJitLogger::LogRecordedBuffer.
-  return 0;
+  return reinterpret_cast<int>(pthread_self());
 #endif
 }
 
 
 // ----------------------------------------------------------------------------
 // POSIX date/time support.
 //
 
 int OS::GetUserTime(uint32_t* secs,  uint32_t* usecs) {
 #if V8_OS_NACL
@@ skipping 395 matching lines @@
 
 void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
   pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
   int result = pthread_setspecific(pthread_key, value);
   DCHECK_EQ(0, result);
   USE(result);
 }
 
 
 } }  // namespace v8::base