| Message ID | 20241101183523.118619-1-mjeanson@efficios.com |
|---|---|
| State | New |
| Headers | show |
| Series | nptl: fix __builtin_thread_pointer detection on LoongArch | expand |
i think the following is better, like powerpc.
diff --git a/sysdeps/loongarch/nptl/thread_pointer.h
b/sysdeps/loongarch/nptl/thread_pointer.h
index 5dec2ef4c6..96ac47ecbf 100644
--- a/sysdeps/loongarch/nptl/thread_pointer.h
+++ b/sysdeps/loongarch/nptl/thread_pointer.h
@@ -19,18 +19,12 @@
#ifndef _SYS_THREAD_POINTER_H
#define _SYS_THREAD_POINTER_H
-#include <sys/cdefs.h>
+register void *__thread_register asm ("$tp");
static inline void *
__thread_pointer (void)
{
-#if __glibc_has_builtin (__builtin_thread_pointer)
- return __builtin_thread_pointer ();
-#else
- void *__thread_register;
- __asm__ ("move %0, $tp" : "=r" (__thread_register));
return __thread_register;
-#endif
}
#endif /* _SYS_THREAD_POINTER_H */
在 2024/11/2 上午2:35, Michael Jeanson 写道:
> Unfortunatly, __has_builtin can't reliably detect [1] if
> __builtin_thread_pointer is implemented in the backend which results in
> build failures with some older GCC versions. Use __GNUC_PREREQ /
> __glibc_clang_prereq instead.
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96952
>
> Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
> ---
> Cc: Yinyu Cai <caiyinyu@loongson.cn>
> Cc: mengqinggang <mengqinggang@loongson.cn>
> Cc: Arjun Shankar <arjun@redhat.com>
> ---
> sysdeps/loongarch/nptl/thread_pointer.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/sysdeps/loongarch/nptl/thread_pointer.h b/sysdeps/loongarch/nptl/thread_pointer.h
> index 5dec2ef4c6..4ab63b5d1f 100644
> --- a/sysdeps/loongarch/nptl/thread_pointer.h
> +++ b/sysdeps/loongarch/nptl/thread_pointer.h
> @@ -19,12 +19,12 @@
> #ifndef _SYS_THREAD_POINTER_H
> #define _SYS_THREAD_POINTER_H
>
> -#include <sys/cdefs.h>
> +#include <features.h>
>
> static inline void *
> __thread_pointer (void)
> {
> -#if __glibc_has_builtin (__builtin_thread_pointer)
> +#if __GNUC_PREREQ (13, 3) || __glibc_clang_prereq (16, 0)
> return __builtin_thread_pointer ();
> #else
> void *__thread_register;
On Sat, 2024-11-02 at 16:33 +0800, caiyinyu wrote: > i think the following is better, like powerpc. > > diff --git a/sysdeps/loongarch/nptl/thread_pointer.h > b/sysdeps/loongarch/nptl/thread_pointer.h > index 5dec2ef4c6..96ac47ecbf 100644 > --- a/sysdeps/loongarch/nptl/thread_pointer.h > +++ b/sysdeps/loongarch/nptl/thread_pointer.h > @@ -19,18 +19,12 @@ > #ifndef _SYS_THREAD_POINTER_H > #define _SYS_THREAD_POINTER_H > > -#include <sys/cdefs.h> > +register void *__thread_register asm ("$tp"); > > static inline void * > __thread_pointer (void) > { > -#if __glibc_has_builtin (__builtin_thread_pointer) > - return __builtin_thread_pointer (); > -#else > - void *__thread_register; > - __asm__ ("move %0, $tp" : "=r" (__thread_register)); > return __thread_register; > -#endif > } > > #endif /* _SYS_THREAD_POINTER_H */ I agree. To me the only advantage of __builtin_thread_pointer is we can use something like void * __thread_pointer (void) { return __builtin_thread_pointer (); } w/o considering the architecture. But now we have to consider the architecture anyway, so I can see no benefit from using __builtin_thread_pointer.
diff --git a/sysdeps/loongarch/nptl/thread_pointer.h b/sysdeps/loongarch/nptl/thread_pointer.h index 5dec2ef4c6..4ab63b5d1f 100644 --- a/sysdeps/loongarch/nptl/thread_pointer.h +++ b/sysdeps/loongarch/nptl/thread_pointer.h @@ -19,12 +19,12 @@ #ifndef _SYS_THREAD_POINTER_H #define _SYS_THREAD_POINTER_H -#include <sys/cdefs.h> +#include <features.h> static inline void * __thread_pointer (void) { -#if __glibc_has_builtin (__builtin_thread_pointer) +#if __GNUC_PREREQ (13, 3) || __glibc_clang_prereq (16, 0) return __builtin_thread_pointer (); #else void *__thread_register;
Unfortunatly, __has_builtin can't reliably detect [1] if __builtin_thread_pointer is implemented in the backend which results in build failures with some older GCC versions. Use __GNUC_PREREQ / __glibc_clang_prereq instead. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96952 Signed-off-by: Michael Jeanson <mjeanson@efficios.com> --- Cc: Yinyu Cai <caiyinyu@loongson.cn> Cc: mengqinggang <mengqinggang@loongson.cn> Cc: Arjun Shankar <arjun@redhat.com> --- sysdeps/loongarch/nptl/thread_pointer.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)