[PATCH] D32782: Add pthread_self function prototype and make it speculatable.

[Xin Tong via Phabricator via llvm-commits]

trentxintong added inline comments.


================
Comment at: lib/Analysis/TargetLibraryInfo.cpp:1182-1184
+  case LibFunc_pthread_self:
+    return NumParams == 0 && FTy.getReturnType()->isIntegerTy();
+
----------------
davide wrote:
> I'm not entirely sure about this bit.
> IIRC POSIX specifies thread ids to be opaque, see:
> 
> ```
>        Thread identifiers should be considered opaque: any attempt to use a
>        thread ID other than in pthreads calls is nonportable and can lead to
>        unspecified results.
> ```
> 
> so this assumption of it being an integer type might not hold.
Yes, I am a bit ambivalent on this as well when i wrote the patch. 
We find library functions by matching its name and its specific function signature. I guess I could leave out the check for the argument here as its opaque and may vary from platform to platform. 
There is a test case in unittest I need to fix if we do this. 


https://reviews.llvm.org/D32782