C++11 atomics

base/atomicops.h

Index: base/atomicops.h
diff --git a/base/atomicops.h b/base/atomicops.h
index f983b455f193d2227b72c42e10caa8ba18708772..fc48a7019b288fb19df4059ace397de3dbf345ce 100644
--- a/base/atomicops.h
+++ b/base/atomicops.h
@@ -144,27 +144,14 @@ Atomic64 Release_Load(volatile const Atomic64* ptr);
 }  // namespace subtle
 }  // namespace base
 
-// Try to use a portable implementation based on C++11 atomics.
-//
-// Some toolchains support C++11 language features without supporting library
-// features (recent compiler, older STL). Whitelist libstdc++ and libc++ that we
-// know will have <atomic> when compiling C++11.
-#if ((__cplusplus >= 201103L) &&                            \
-     ((defined(__GLIBCXX__) && (__GLIBCXX__ > 20110216)) || \
-      (defined(_LIBCPP_VERSION) && (_LIBCPP_STD_VER >= 11))))
+#if (defined(OS_WIN) && defined(COMPILER_MSVC) && \

[Nico, 2015/12/07 03:55:58]

OS_WIN implies COMPILER_MSVC, remove the COMPILER_MSVC bit

[JF, 2015/12/07 04:23:31]

That's true when using LLVM on Windows as well? I'll do the change, we can put
back MSVC if not.

[Nico, 2015/12/07 04:58:28]

Yes. Just like clang defines__gnuc__ when using the GCC compatible driver, it
defines _MSc_ver when using the cl compatible driver.

+     defined(ARCH_CPU_X86_FAMILY))

[Nico, 2015/12/07 03:55:58]

We don't have a win/arm build either, so you can get rid of this too I think

…oh, this is copied from the lhs. Then it's fine as-is I suppose, but I'd
simplify it while here. Up to you.

[JF, 2015/12/07 04:23:31]

Removed, you're right it shouldn't have been there in the first place. Maybe
someone was too hopeful about Windows RT :-)

+// TODO(jfb): The MSVC header includes windows.h, which other files end up
+//            relying on. Fix this as part of crbug.com/559247.
+#  include "base/atomicops_internals_x86_msvc.h"
+#else
 #  include "base/atomicops_internals_portable.h"
-#else  // Otherwise use a platform specific implementation.
-#  if defined(THREAD_SANITIZER)
-#    error "Thread sanitizer must use the portable atomic operations"
-#  elif (defined(OS_WIN) && defined(COMPILER_MSVC) && \
-         defined(ARCH_CPU_X86_FAMILY))
-#    include "base/atomicops_internals_x86_msvc.h"
-#  elif defined(OS_MACOSX)
-#    include "base/atomicops_internals_mac.h"
-#  else
-#    error "Atomic operations are not supported on your platform"
-#  endif
-#endif   // Portable / non-portable includes.
+#endif
 
 // On some platforms we need additional declarations to make
 // AtomicWord compatible with our other Atomic* types.