[PATCH] Add implementations of __readfs{byte, word, dword, qword} to Intrin.h

[Reid Kleckner]

This is the address space extension for accessing TLS:
http://clang.llvm.org/docs/LanguageExtensions.html#x86-x86-64-language-extensions

That's a lot cleaner.  Let's do that.


On Thu, Jan 23, 2014 at 10:38 AM, Hans Wennborg <hans at chromium.org> wrote:

>   Addressed rnk's comments.
>
>   Chandler: can you provide a pointer to the address space technique you
> mentioned?
>
> Hi rnk, whunt,
>
> http://llvm-reviews.chandlerc.com/D2606
>
> CHANGE SINCE LAST DIFF
>   http://llvm-reviews.chandlerc.com/D2606?vs=6606&id=6607#toc
>
> Files:
>   lib/Headers/Intrin.h
>
> Index: lib/Headers/Intrin.h
> ===================================================================
> --- lib/Headers/Intrin.h
> +++ lib/Headers/Intrin.h
> @@ -101,9 +101,13 @@
>  unsigned long __readcr8(void);
>  unsigned int __readdr(unsigned int);
>  unsigned int __readeflags(void);
> +static __inline__
>  unsigned char __readfsbyte(unsigned long);
> +static __inline__
>  unsigned long __readfsdword(unsigned long);
> +static __inline__
>  unsigned __int64 __readfsqword(unsigned long);
> +static __inline__
>  unsigned short __readfsword(unsigned long);
>  unsigned __int64 __readmsr(unsigned long);
>  unsigned __int64 __readpmc(unsigned long);
> @@ -767,6 +771,33 @@
>    __asm__ volatile ("" : : : "memory");
>  }
>
>  /*----------------------------------------------------------------------------*\
> +|* readfs
>
> +\*----------------------------------------------------------------------------*/
> +static __inline__ unsigned char __attribute__((__always_inline__,
> __nodebug__))
> +__readfsbyte(unsigned long __offset) {
> +  unsigned char __result;
> +  __asm__ ("movb %%fs:(%1), %0" : "=r" (__result) : "r" (__offset));
> +  return __result;
> +}
> +static __inline__ unsigned long __attribute__((__always_inline__,
> __nodebug__))
> +__readfsdword(unsigned long __offset) {
> +  unsigned long __result;
> +  __asm__ ("movl %%fs:(%1), %0" : "=r" (__result) : "r" (__offset));
> +  return __result;
> +}
> +static __inline__ unsigned __int64 __attribute__((__always_inline__,
> __nodebug__))
> +__readfsqword(unsigned long __offset) {
> +  unsigned __int64 __result;
> +  __asm__ ("movq %%fs:(%1), %0" : "=r" (__result) : "r" (__offset));
> +  return __result;
> +}
> +static __inline__ unsigned short __attribute__((__always_inline__,
> __nodebug__))
> +__readfsword(unsigned long __offset) {
> +  unsigned short __result;
> +  __asm__ ("movw %%fs:(%1), %0" : "=r" (__result) : "r" (__offset));
> +  return __result;
> +}
>
> +/*----------------------------------------------------------------------------*\
>  |* Misc
>
>  \*----------------------------------------------------------------------------*/
>  static __inline__ void * __attribute__((__always_inline__, __nodebug__))
>
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