Move WTF::SpinLock to base::SpinLock.

base/synchronization/spin_lock.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "wtf/SpinLock.h"
+#include "base/synchronization/spin_lock.h"
 
-#include "wtf/Atomics.h"
-#include "wtf/CPU.h"
-#include "wtf/Compiler.h"
-
-#if OS(WIN)
+#if defined(OS_WIN)
 #include <windows.h>
-#elif OS(POSIX)
+#elif defined(OS_POSIX)
 #include <sched.h>
 #endif
 
 // The YIELD_PROCESSOR macro wraps an architecture specific-instruction that
 // informs the processor we're in a busy wait, so it can handle the branch more
 // intelligently and e.g. reduce power to our core or give more resources to the
 // other hyper-thread on this core. See the following for context:
 // https://software.intel.com/en-us/articles/benefitting-power-and-performance-sleep-loops
 //
-// The YIELD_THREAD macro tells the OS to relinquish our quanta. This is
+// The YIELD_THREAD macro tells the OS to relinquish our quantum. This is
 // basically a worst-case fallback, and if you're hitting it with any frequency
-// you really should be using proper lock rather than these spinlocks.
-#if OS(WIN)
+// you really should be using a proper lock (such as |base::Lock|)rather than
+// these spinlocks.
+#if defined(OS_WIN)
 #define YIELD_PROCESSOR YieldProcessor()
 #define YIELD_THREAD SwitchToThread()
-#elif COMPILER(GCC) || COMPILER(CLANG)
-#if CPU(X86_64) || CPU(X86)
+#elif defined(COMPILER_GCC) || defined(__clang__)
+#if defined(ARCH_CPU_X86_64) || defined(ARCH_CPU_X86)
 #define YIELD_PROCESSOR __asm__ __volatile__("pause")
-#elif CPU(ARM) || CPU(ARM64)
+#elif defined(ARCH_CPU_ARMEL) || defined(ARCH_CPU_ARM64)
 #define YIELD_PROCESSOR __asm__ __volatile__("yield")
-#elif CPU(MIPS)
+#elif defined(ARCH_CPU_MIPSEL)
 // The MIPS32 docs state that the PAUSE instruction is a no-op on older
 // architectures (first added in MIPS32r2). To avoid assembler errors when
 // targeting pre-r2, we must encode the instruction manually.
 #define YIELD_PROCESSOR __asm__ __volatile__(".word 0x00000140")
-#elif CPU(MIPS64) && __mips_isa_rev >= 2
+#elif defined(ARCH_CPU_MIPS64EL) && __mips_isa_rev >= 2
 // Don't bother doing using .word here since r2 is the lowest supported mips64
 // that Chromium supports.
 #define YIELD_PROCESSOR __asm__ __volatile__("pause")
 #endif
 #endif
 
 #ifndef YIELD_PROCESSOR
 #warning "Processor yield not supported on this architecture."
 #define YIELD_PROCESSOR ((void)0)
 #endif
 
 #ifndef YIELD_THREAD
-#if OS(POSIX)
+#if defined(OS_POSIX)
 #define YIELD_THREAD sched_yield()
 #else
 #warning "Thread yield not supported on this OS."
 #define YIELD_THREAD ((void)0)
 #endif
 #endif
 
-namespace WTF {
+namespace base {
+namespace subtle {
 
-void SpinLock::lockSlow() {
-  // The value of kYieldProcessorTries is cargo culted from TCMalloc, Windows
+void SpinLock::LockSlow() {
+  // The value of |kYieldProcessorTries| is cargo culted from TCMalloc, Windows
   // critical section defaults, and various other recommendations.
   // TODO(jschuh): Further tuning may be warranted.
   static const int kYieldProcessorTries = 1000;
   do {
     do {
       for (int count = 0; count < kYieldProcessorTries; ++count) {
-        // Let the Processor know we're spinning.
+        // Let the processor know we're spinning.
         YIELD_PROCESSOR;
-        if (!m_lock.load(std::memory_order_relaxed) &&
-            LIKELY(!m_lock.exchange(true, std::memory_order_acquire)))
+        if (!lock_.load(std::memory_order_relaxed) &&
+            LIKELY(!lock_.exchange(true, std::memory_order_acquire)))
           return;
       }
 
       // Give the OS a chance to schedule something on this core.
       YIELD_THREAD;
-    } while (m_lock.load(std::memory_order_relaxed));
-  } while (UNLIKELY(m_lock.exchange(true, std::memory_order_acquire)));
+    } while (lock_.load(std::memory_order_relaxed));
+  } while (UNLIKELY(lock_.exchange(true, std::memory_order_acquire)));
 }
 
-}  // namespace WTF
+}  // namespace subtle
+}  // namespace base