diff options
| author | JF Bastien <jfb@chromium.org> | 2013-07-30 16:38:26 -0700 |
|---|---|---|
| committer | JF Bastien <jfb@chromium.org> | 2013-07-30 16:38:26 -0700 |
| commit | f75fd0a9f95109b9cb13a74aad6dcc98c3d5d625 (patch) | |
| tree | 652c465d76008ef58f5c8d55827050a6f1d875e1 /docs | |
| parent | 423b3bb89c78e96c59843aa7c6e55d01bde174d1 (diff) | |
Rewrite ``asm("":::"memory")`` to ``fence seq_cst``
This is often used as a compiler barrier and should "just work" in user code.
BUG= https://code.google.com/p/nativeclient/issues/detail?id=2345
R=eliben@chromium.org
TEST= (cd ./pnacl/build/llvm_x86_64 && ninja check-all)
Review URL: https://codereview.chromium.org/21178002
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/PNaClDeveloperGuide.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/docs/PNaClDeveloperGuide.rst b/docs/PNaClDeveloperGuide.rst index 7bd45dd6fd..b0a47423e3 100644 --- a/docs/PNaClDeveloperGuide.rst +++ b/docs/PNaClDeveloperGuide.rst @@ -130,3 +130,10 @@ As in C11/C++11: these primitives must always be of the same bit size for that location. - Not all memory orderings are valid for all atomic operations. +Inline Assembly +=============== + +Inline assembly isn't supported by PNaCl because it isn't portable. The +one current exception is the common compiler barrier idiom +``asm("":::"memory")``, which gets transformed to a sequentially +consistent memory barrier (equivalent to ``__sync_synchronize()``). |