4.1/4.2 PATCH: Restore weak definitions of pthread functions on Tru64 UNIX (PR target/28307)

[Rainer Orth <ro at TechFak dot Uni-Bielefeld dot DE>]

This patch fixes the issues described in PRs libgcj/28189

[4.1/4.2 Regression] Many libjava execution tests time out on Tru64 UNIX

and target/28307

[4.1/4.2 Regression] pthread functions in libgcc not weak any more on Tru64 UNIX

It turns out that this patch

005-11-09  Alexandre Oliva  <aoliva@redhat.com>

        PR other/4372
        * gthr-dce.h, gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
        gthr-tpf.h: Define __gthrw.  For all identifiers that might
        be weak, introduce weakrefs or non-weak aliases with __gthrw,
        and prefix all uses with __ghtrw.

turned all definitions of pthread functions in libgcc* on Tru64 UNIX from
weak definitions into strong definitions by losing the #pragma weak
declarations.  This breaks gctest (where I discovered the issue as
described in the PR), causes many ACATS failures and most libjava tests to
time out, so a full bootstrap and test cycle on Tru64 UNIX takes several
days ;-(

Once the root cause became clear, the fix became fairly trivial: via a new
__gthrw_pragma macro, the missing #pragma weak declarations are
reintroduced on Tru64 UNIX by providing a non-default definition in
gthr-posix.c where they are necessary to make the function weak.

With this patch (and a couple of other fixes or workarounds for much
unrelated breakage ;-), I could finally get a clean mainline bootstrap on
alpha-dec-osf4.0f and much better test results than I had in months:

	http://gcc.gnu.org/ml/gcc-testresults/2006-07/msg00509.html

Since this is a regression on both mainline and the 4.1 branch, ok for both?
Mainline testing already finished successfully, I need to test the 4.1
branch before committing, but the issues is the same there.

	Rainer

-----------------------------------------------------------------------------
Rainer Orth, Faculty of Technology, Bielefeld University


Wed Jul 12 21:16:20 2006  Rainer Orth  <ro@TechFak.Uni-Bielefeld.DE>

	PR target/28307
	* gthr-posix.h [SUPPORTS_WEAK && GTHREAD_USE_WEAK]
	(__gthrw_pragma): Provide default definition.
	(__gthrw2): Use it.
	* gthr-posix.c (__gthrw_pragma): Define.

Index: gcc/gthr-posix.c
===================================================================
--- gcc/gthr-posix.c	(revision 115313)
+++ gcc/gthr-posix.c	(working copy)
@@ -1,6 +1,6 @@
 /* POSIX threads dummy routines for systems without weak definitions.  */
 /* Compile this one with gcc.  */
-/* Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -28,6 +28,7 @@ Software Foundation, 51 Franklin Street,
 
 #include "tconfig.h"
 #include "tm.h"
+# define __gthrw_pragma(pragma) _Pragma (#pragma)
 /* Define so we provide weak definitions of functions used by libobjc only.  */
 #define _LIBOBJC_WEAK
 #include "gthr.h"
@@ -75,7 +76,7 @@ pthread_create (pthread_t *thread ATTRIB
 }
 
 int
-pthread_cancel(pthread_t thread ATTRIBUTE_UNUSED)
+pthread_cancel (pthread_t thread ATTRIBUTE_UNUSED)
 {
   return 0;
 }
Index: gcc/gthr-posix.h
===================================================================
--- gcc/gthr-posix.h	(revision 115313)
+++ gcc/gthr-posix.h	(working copy)
@@ -59,8 +59,12 @@ typedef pthread_mutex_t __gthread_recurs
 #endif
 
 #if SUPPORTS_WEAK && GTHREAD_USE_WEAK
+# ifndef __gthrw_pragma
+#  define __gthrw_pragma(pragma)
+# endif
 # define __gthrw2(name,name2,type) \
-  static __typeof(type) name __attribute__ ((__weakref__(#name2)));
+  static __typeof(type) name __attribute__ ((__weakref__(#name2))); \
+  __gthrw_pragma(weak type)
 # define __gthrw_(name) __gthrw_ ## name
 #else
 # define __gthrw2(name,name2,type)