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Diffstat (limited to 'lib/sanitizer_common/sanitizer_atomic_clang.h')
-rw-r--r--lib/sanitizer_common/sanitizer_atomic_clang.h71
1 files changed, 18 insertions, 53 deletions
diff --git a/lib/sanitizer_common/sanitizer_atomic_clang.h b/lib/sanitizer_common/sanitizer_atomic_clang.h
index c5aa939b58c44..38363e8755606 100644
--- a/lib/sanitizer_common/sanitizer_atomic_clang.h
+++ b/lib/sanitizer_common/sanitizer_atomic_clang.h
@@ -15,8 +15,26 @@
#ifndef SANITIZER_ATOMIC_CLANG_H
#define SANITIZER_ATOMIC_CLANG_H
+#if defined(__i386__) || defined(__x86_64__)
+# include "sanitizer_atomic_clang_x86.h"
+#else
+# include "sanitizer_atomic_clang_other.h"
+#endif
+
namespace __sanitizer {
+// We would like to just use compiler builtin atomic operations
+// for loads and stores, but they are mostly broken in clang:
+// - they lead to vastly inefficient code generation
+// (http://llvm.org/bugs/show_bug.cgi?id=17281)
+// - 64-bit atomic operations are not implemented on x86_32
+// (http://llvm.org/bugs/show_bug.cgi?id=15034)
+// - they are not implemented on ARM
+// error: undefined reference to '__atomic_load_4'
+
+// See http://www.cl.cam.ac.uk/~pes20/cpp/cpp0xmappings.html
+// for mappings of the memory model to different processors.
+
INLINE void atomic_signal_fence(memory_order) {
__asm__ __volatile__("" ::: "memory");
}
@@ -25,59 +43,6 @@ INLINE void atomic_thread_fence(memory_order) {
__sync_synchronize();
}
-INLINE void proc_yield(int cnt) {
- __asm__ __volatile__("" ::: "memory");
-#if defined(__i386__) || defined(__x86_64__)
- for (int i = 0; i < cnt; i++)
- __asm__ __volatile__("pause");
-#endif
- __asm__ __volatile__("" ::: "memory");
-}
-
-template<typename T>
-INLINE typename T::Type atomic_load(
- const volatile T *a, memory_order mo) {
- DCHECK(mo & (memory_order_relaxed | memory_order_consume
- | memory_order_acquire | memory_order_seq_cst));
- DCHECK(!((uptr)a % sizeof(*a)));
- typename T::Type v;
- // FIXME:
- // 64-bit atomic operations are not atomic on 32-bit platforms.
- // The implementation lacks necessary memory fences on ARM/PPC.
- // We would like to use compiler builtin atomic operations,
- // but they are mostly broken:
- // - they lead to vastly inefficient code generation
- // (http://llvm.org/bugs/show_bug.cgi?id=17281)
- // - 64-bit atomic operations are not implemented on x86_32
- // (http://llvm.org/bugs/show_bug.cgi?id=15034)
- // - they are not implemented on ARM
- // error: undefined reference to '__atomic_load_4'
- if (mo == memory_order_relaxed) {
- v = a->val_dont_use;
- } else {
- atomic_signal_fence(memory_order_seq_cst);
- v = a->val_dont_use;
- atomic_signal_fence(memory_order_seq_cst);
- }
- return v;
-}
-
-template<typename T>
-INLINE void atomic_store(volatile T *a, typename T::Type v, memory_order mo) {
- DCHECK(mo & (memory_order_relaxed | memory_order_release
- | memory_order_seq_cst));
- DCHECK(!((uptr)a % sizeof(*a)));
- if (mo == memory_order_relaxed) {
- a->val_dont_use = v;
- } else {
- atomic_signal_fence(memory_order_seq_cst);
- a->val_dont_use = v;
- atomic_signal_fence(memory_order_seq_cst);
- }
- if (mo == memory_order_seq_cst)
- atomic_thread_fence(memory_order_seq_cst);
-}
-
template<typename T>
INLINE typename T::Type atomic_fetch_add(volatile T *a,
typename T::Type v, memory_order mo) {