[PATCH] linuxthreads pthread_cond_t

[PATCH] linuxthreads pthread_cond_t

[Jakub Jelinek]

Hi!

pthread_cond_t in NPTL wants long long alignment, so linuxthreads
should do the same, otherwise on 32-bit arches where
__alignof(long long) > 4 binaries/libs compiled against linuxthreads
-lpthread might not work with NPTL libs.
Haven't used __attribute__((aligned (__alignof__ (long long))))
to cope with non-GCC compilers.

2003-01-02  Jakub Jelinek  <jakub@redhat.com>

	* sysdeps/pthread/bits/pthreadtypes.h (__pthread_cond_align_t): New
	type.
	(pthread_cond_t): Add __align member, shorten __padding.
	* sysdeps/pthread/pthread.h (PHTREAD_COND_INITIALIZER): Initialize
	__padding and __align too.

--- libc/linuxthreads/sysdeps/pthread/bits/pthreadtypes.h.jj	2003-01-02 14:49:58.000000000 +0100
+++ libc/linuxthreads/sysdeps/pthread/bits/pthreadtypes.h	2003-01-02 19:57:25.000000000 +0100
@@ -53,12 +53,20 @@ typedef struct __pthread_attr_s
 
 
 /* Conditions (not abstract because of PTHREAD_COND_INITIALIZER */
+
+#ifdef __GLIBC_HAVE_LONG_LONG
+__extension__ typedef long long __pthread_cond_align_t;
+#else
+typedef long __pthread_cond_align_t;
+#endif
+
 typedef struct
 {
   struct _pthread_fastlock __c_lock; /* Protect against concurrent access */
   _pthread_descr __c_waiting;        /* Threads waiting on this condition */
   char __padding[48 - sizeof (struct _pthread_fastlock)
-		 - sizeof (_pthread_descr)];
+		 - sizeof (_pthread_descr) - sizeof (__pthread_cond_align_t)];
+  __pthread_cond_align_t __align;
 } pthread_cond_t;
 
 
--- libc/linuxthreads/sysdeps/pthread/pthread.h.jj	2002-06-05 10:27:29.000000000 +0200
+++ libc/linuxthreads/sysdeps/pthread/pthread.h	2003-01-02 20:20:34.000000000 +0100
@@ -41,7 +41,7 @@ __BEGIN_DECLS
   {0, 0, 0, PTHREAD_MUTEX_ADAPTIVE_NP, __LOCK_INITIALIZER}
 #endif
 
-#define PTHREAD_COND_INITIALIZER {__LOCK_INITIALIZER, 0}
+#define PTHREAD_COND_INITIALIZER {__LOCK_INITIALIZER, 0, "", 0}
 
 #ifdef __USE_UNIX98
 # define PTHREAD_RWLOCK_INITIALIZER \

	Jakub

Re: [PATCH] linuxthreads pthread_cond_t

[Roland McGrath]

This doesn't help existing binaries where pthread_cond_t may be allocated
without sufficient alignment for NPTL.

Re: [PATCH] linuxthreads pthread_cond_t

[Ulrich Drepper]

Roland McGrath wrote:
> This doesn't help existing binaries where pthread_cond_t may be allocated
> without sufficient alignment for NPTL.

Nope, read the code.  THere are no existing binaries which allocate
structures of this type.

-- 
--------------.                        ,-.            444 Castro Street
Ulrich Drepper \    ,-----------------'   \ Mountain View, CA 94041 USA
Red Hat         `--' drepper at redhat.com `---------------------------

Re: [PATCH] linuxthreads pthread_cond_t

[Jakub Jelinek]

On Thu, Jan 02, 2003 at 11:37:08AM -0800, Roland McGrath wrote:
> This doesn't help existing binaries where pthread_cond_t may be allocated
> without sufficient alignment for NPTL.

Why? The old pthread_cond_t (accessed through pthread_cond_*@GLIBC_2.0)
does not have this alignment requirement (and is much smaller too).
old_pthread_cond* wrap this by mallocing/freeing the new pthread_cond_t
and storing the pointer to it into the old pthread_cond_t.

	Jakub