Add __attribute_access_none to disable GCC warnings [BZ #27714]

GCC 11 warns when a pointer to an uninitialized object is passed
to a function that takes a const-qualified argument.  This is done
on the assumption that most such functions read from the object.
For the rare case of a function that doesn't, GCC 11 extends
attribute access to add a new mode called none.

POSIX pthread_setspecific() is one such rare function that takes
a const void* argument but that doesn't read from the object it
points to.  To suppress the -Wmaybe-uninitialized issued by GCC
11 when the address of an uninitialized object is passed to it
(e.g., the result of malloc()), this change #defines
__attr_access_none in cdefs.h and uses the macro on the function
in sysdeps/htl/pthread.h and sysdeps/nptl/pthread.h.

1 files changed, 2 insertions, 1 deletions

diff --git a/sysdeps/nptl/pthread.h b/sysdeps/nptl/pthread.h
index c363552f6c..af0c156c89 100644
--- a/sysdeps/nptl/pthread.h
+++ b/sysdeps/nptl/pthread.h
@@ -1182,7 +1182,8 @@ extern void *pthread_getspecific (pthread_key_t __key) __THROW;
 
 /* Store POINTER in the thread-specific data slot identified by KEY. */
 extern int pthread_setspecific (pthread_key_t __key,
-				const void *__pointer) __THROW ;
+				const void *__pointer)
+  __THROW __attr_access_none (2);
 
 
 #ifdef __USE_XOPEN2K