From b5df72c050189f28103eb8aeaa1e23d399eeb413 Mon Sep 17 00:00:00 2001
From: nnoble <nnoble@google.com>
Date: Mon, 8 Dec 2014 19:29:55 -0800
Subject: [PATCH] Restoring atm_sync as it was lost during The Great Migration.
Change on 2014/12/08 by nnoble <nnoble@google.com> -------------
Created by MOE: http://code.google.com/p/moe-java MOE_MIGRATED_REVID=81636458
---
include/grpc/support/atm_gcc_sync.h | 46 ++++++++++++++++-------------
1 file changed, 25 insertions(+), 21 deletions(-)
diff --git a/include/grpc/support/atm_gcc_sync.h b/include/grpc/support/atm_gcc_sync.h
index 30570da540..976f2977bb 100644
--- a/include/grpc/support/atm_gcc_sync.h
+++ b/include/grpc/support/atm_gcc_sync.h
@@ -34,36 +34,40 @@
#ifndef __GRPC_SUPPORT_ATM_GCC_SYNC_H__
#define __GRPC_SUPPORT_ATM_GCC_SYNC_H__
-/* atm_platform.h for gcc and gcc-like compilers with the
- __atomic_* interface. */
+/* variant of atm_platform.h for gcc and gcc-like compiers with __sync_*
+ interface */
#include <grpc/support/port_platform.h>
typedef gpr_intptr gpr_atm;
-#define gpr_atm_full_barrier() (__atomic_thread_fence(__ATOMIC_SEQ_CST))
+#if defined(__i386) || defined(__x86_64__)
+/* All loads are acquire loads and all stores are release stores. */
+#define GPR_ATM_LS_BARRIER_() __asm__ __volatile__("" : : : "memory")
+#else
+#define GPR_ATM_LS_BARRIER_() gpr_atm_full_barrier()
+#endif
-#define gpr_atm_acq_load(p) (__atomic_load_n((p), __ATOMIC_ACQUIRE))
-#define gpr_atm_rel_store(p, value) \
- (__atomic_store_n((p), (gpr_intptr)(value), __ATOMIC_RELEASE))
+#define gpr_atm_full_barrier() (__sync_synchronize())
-#define gpr_atm_no_barrier_fetch_add(p, delta) \
- (__atomic_fetch_add((p), (gpr_intptr)(delta), __ATOMIC_RELAXED))
-#define gpr_atm_full_fetch_add(p, delta) \
- (__atomic_fetch_add((p), (gpr_intptr)(delta), __ATOMIC_ACQ_REL))
-
-static __inline int gpr_atm_no_barrier_cas(gpr_atm *p, gpr_atm o, gpr_atm n) {
- return __atomic_compare_exchange_n(p, &o, n, 0, __ATOMIC_RELAXED,
- __ATOMIC_RELAXED);
+static __inline gpr_atm gpr_atm_acq_load(const gpr_atm *p) {
+ gpr_atm value = *p;
+ GPR_ATM_LS_BARRIER_();
+ return value;
}
-static __inline int gpr_atm_acq_cas(gpr_atm *p, gpr_atm o, gpr_atm n) {
- return __atomic_compare_exchange_n(p, &o, n, 0, __ATOMIC_ACQUIRE,
- __ATOMIC_RELAXED);
+static __inline void gpr_atm_rel_store(gpr_atm *p, gpr_atm value) {
+ GPR_ATM_LS_BARRIER_();
+ *p = value;
}
-static __inline int gpr_atm_rel_cas(gpr_atm *p, gpr_atm o, gpr_atm n) {
- return __atomic_compare_exchange_n(p, &o, n, 0, __ATOMIC_RELEASE,
- __ATOMIC_RELAXED);
-}
+#undef GPR_ATM_LS_BARRIER_
+
+#define gpr_atm_no_barrier_fetch_add(p, delta) \
+ gpr_atm_full_fetch_add((p), (delta))
+#define gpr_atm_full_fetch_add(p, delta) (__sync_fetch_and_add((p), (delta)))
+
+#define gpr_atm_no_barrier_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
+#define gpr_atm_acq_cas(p, o, n) (__sync_bool_compare_and_swap((p), (o), (n)))
+#define gpr_atm_rel_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
#endif /* __GRPC_SUPPORT_ATM_GCC_SYNC_H__ */
--
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