[PATCH] D19582: [X86] Add support for llvm.thread.pointer

[Marcin Kościelnicki via llvm-commits]

koriakin added a comment.

In http://reviews.llvm.org/D19582#421480, @reames wrote:

> This is missing documentation.  It *looks* like you're trying to get the 
>  thread local storage pointer.  Is that correct?  This can't be reviewed 
>  without context and documented intent.
>
> Philip


This is indeed intended to fetch the TLS pointer: http://llvm.org/docs/LangRef.html#llvm-thread-pointer-intrinsic .  For x86, this is simply the FS/GS base, ie. pointer to end of the TLS area. The intent is to support __builtin_thread_pointer() in clang, which comes useful in some strange places (eg. sanitizer_common uses it for aarch64, and could use it for x86 too if only gcc supported it as well).


Repository:
  rL LLVM

http://reviews.llvm.org/D19582