Index: base/atomicops.h |
diff --git a/base/atomicops.h b/base/atomicops.h |
index 84be8c04bc00e57ebbd701c803d2b3c24a314723..833e1704291b1d55842e985a4d8dc7c2948d9520 100644 |
--- a/base/atomicops.h |
+++ b/base/atomicops.h |
@@ -28,8 +28,11 @@ |
#ifndef BASE_ATOMICOPS_H_ |
#define BASE_ATOMICOPS_H_ |
+#include <cassert> // Small C++ header which defines implementation specific |
+ // macros used to identify the STL implementation. |
#include <stdint.h> |
+#include "base/base_export.h" |
#include "build/build_config.h" |
#if defined(OS_WIN) && defined(ARCH_CPU_64_BITS) |
@@ -137,28 +140,66 @@ Atomic64 Release_Load(volatile const Atomic64* ptr); |
} // namespace subtle |
} // namespace base |
-// Include our platform specific implementation. |
-#if defined(THREAD_SANITIZER) |
-#include "base/atomicops_internals_tsan.h" |
-#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" |
-#elif defined(OS_NACL) |
-#include "base/atomicops_internals_gcc.h" |
-#elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARMEL) |
-#include "base/atomicops_internals_arm_gcc.h" |
-#elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARM64) |
-#include "base/atomicops_internals_arm64_gcc.h" |
-#elif defined(COMPILER_GCC) && defined(ARCH_CPU_X86_FAMILY) |
-#include "base/atomicops_internals_x86_gcc.h" |
-#elif defined(COMPILER_GCC) && \ |
- (defined(ARCH_CPU_MIPS_FAMILY) || defined(ARCH_CPU_MIPS64_FAMILY)) |
-#include "base/atomicops_internals_mips_gcc.h" |
-#else |
-#error "Atomic operations are not supported on your platform" |
+// The following x86 CPU features are used in atomicops_internals_x86_gcc.h, but |
+// this file is duplicated inside of Chrome: protobuf and tcmalloc rely on the |
+// struct being present at link time. Some parts of Chrome can currently use the |
+// portable interface whereas others still use GCC one. The include guards are |
+// the same as in atomicops_internals_x86_gcc.cc. |
+#if defined(__i386__) || defined(__x86_64__) |
+// This struct is not part of the public API of this module; clients may not |
+// use it. (However, it's exported via BASE_EXPORT because clients implicitly |
+// do use it at link time by inlining these functions.) |
+// Features of this x86. Values may not be correct before main() is run, |
+// but are set conservatively. |
+struct AtomicOps_x86CPUFeatureStruct { |
+ bool has_amd_lock_mb_bug; // Processor has AMD memory-barrier bug; do lfence |
+ // after acquire compare-and-swap. |
+ // The following fields are unused by Chrome's base implementation but are |
+ // still used by copies of the same code in other parts of the code base. This |
+ // causes an ODR violation, and the other code is likely reading invalid |
+ // memory. |
+ // TODO(jfb) Delete these fields once the rest of the Chrome code base doesn't |
+ // depend on them. |
+ bool has_sse2; // Processor has SSE2. |
+ bool has_cmpxchg16b; // Processor supports cmpxchg16b instruction. |
+}; |
+BASE_EXPORT extern struct AtomicOps_x86CPUFeatureStruct |
+ AtomicOps_Internalx86CPUFeatures; |
#endif |
+// 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)))) |
+# 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" |
+# elif defined(OS_NACL) |
+# include "base/atomicops_internals_gcc.h" |
+# elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARMEL) |
+# include "base/atomicops_internals_arm_gcc.h" |
+# elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARM64) |
+# include "base/atomicops_internals_arm64_gcc.h" |
+# elif defined(COMPILER_GCC) && defined(ARCH_CPU_X86_FAMILY) |
+# include "base/atomicops_internals_x86_gcc.h" |
+# elif (defined(COMPILER_GCC) && \ |
+ (defined(ARCH_CPU_MIPS_FAMILY) || defined(ARCH_CPU_MIPS64_FAMILY))) |
+# include "base/atomicops_internals_mips_gcc.h" |
+# else |
+# error "Atomic operations are not supported on your platform" |
+# endif |
+#endif // Portable / non-portable includes. |
+ |
// On some platforms we need additional declarations to make |
// AtomicWord compatible with our other Atomic* types. |
#if defined(OS_MACOSX) || defined(OS_OPENBSD) |