generic atomicops: promote Acquire_Store() and Release_Load() to use SEQ_CST fence #30
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…SEQ_CST fence
__atomic_store_n() cannot take a memory model argument of
__ATOMIC_ACQUIRE, and __atomic_load_n() cannot take a memory model
argument of __ATOMIC_RELEASE, per the GCC documentation:
https://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fatomic-Builtins.html
On Clang this generates a -Watomic-memory-ordering warning.
Promote the fences in Acquire_Store() and Release_Load() to the stronger
__ATOMIC_SEQ_CST memory model, which ought to be safe.
Note that there are no actual uses of Acquire_Store() or Release_Load()
in protobuf, though.
This follows the TSAN atomicops implementation, which also uses SEQ_CST
fences for these functions.
(Fixes #25.)
|
Note that if you merge this instead, it obsoletes PR #28. |
xfxyjwf
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Sep 19, 2014
…mory_models generic atomicops: promote Acquire_Store() and Release_Load() to use SEQ_CST fence
TeBoring
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Jan 19, 2019
Fixed some bad bugs in upb_env.
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__atomic_store_n() cannot take a memory model argument of
__ATOMIC_ACQUIRE, and __atomic_load_n() cannot take a memory model
argument of __ATOMIC_RELEASE, per the GCC documentation:
On Clang this generates a -Watomic-memory-ordering warning.
Promote the fences in Acquire_Store() and Release_Load() to the stronger
__ATOMIC_SEQ_CST memory model, which ought to be safe.
Note that there are no actual uses of Acquire_Store() or Release_Load()
in protobuf, though.
This follows the TSAN atomicops implementation, which also uses SEQ_CST
fences for these functions.
(Fixes #25.)