Re: MT-safe exception and thread library

Re: MT-safe exception and thread library

[Andrew Zabolotny]

On Wed, 17 Dec 1997 13:48:26 +0100, Teemu Torma wrote:

>    One more thing: the flag.  How about -fthreads instead of -threads?
>And what if there are multiple thread libraries?  There are, at
>least in Solaris 2.5.  
I'm not sure if this is applicable, but OS/2 resolves this following way
(since `93 or `94):
In target makefile fragment:
# Allow multi-threaded/single-threaded libraries
MULTILIB_OPTIONS    = Zmt
MULTILIB_DIRNAMES   = mt st
MULTILIB_MATCHES    = Zmt=Zmts Zmt=Zmtd
MULTILIB_EXCEPTIONS =
MULTILIB_EXTRA_OPTS =

and with a few changes to
-----------------------------------------------------------
diff -rcwB pgcc-1.0/gcc/genmultilib pgcc-1.0-emx/gcc/genmultilib
*** pgcc-1.0/gcc/genmultilib	Mon Aug 11 18:57:08 1997
--- pgcc-1.0-emx/gcc/genmultilib	Mon Dec  8 23:08:38 1997
***************
*** 35,40 ****
--- 35,43 ----
  # elements in the second list are separated by spaces.  If the second
  # argument is empty, the option names will be used as the directory
  # names.
+ # If number of elements in second argument is bigger than number of
options
+ # in the first argument, the n+1'th element is used as default directory
+ # name (i.e. when no one of options specified in argument 1 was used)
  
  # The optional third argument is a list of options which are
  # identical.  The elements in the list are separated by spaces.  Each
***************
*** 164,169 ****
--- 167,178 ----
    done
  fi
  
+ # See if default directory was specified
+ if [ -n "$1" ]; then
+   defaultdir="$1"
+ else
+   defaultdir="."
+ fi
  # We need another recursive shell script to correctly handle positive
  # matches.  If we are invoked as
  #   genmultilib "opt1 opt2" "" "opt1=nopt1 opt2=nopt2"
***************
*** 203,209 ****
    done
  done
  optout=`echo ${optout} | sed -e 's/^ //'`
! echo "\". ${optout};\","
  
  # Work over the list of combinations.  We have to translate each one
  # to use the directory names rather than the option names, we have to
--- 212,218 ----
    done
  done
  optout=`echo ${optout} | sed -e 's/^ //'`
! echo "\"${defaultdir} ${optout};\","
  
  # Work over the list of combinations.  We have to translate each one
  # to use the directory names rather than the option names, we have to
-----------------------------the end----------------------------

It also would be nice to define some symbol (OS/2 defines __MT__ -- are
there other standards? If yes, it would be The Right Thing {tm} to define
some unique symbol everywhere (on all platforms), and all other symbols
depending on target platform) when using -mthreads (this is needed, for
example C headers checks it for a thread-aware errno). And it looks stupid
to me to make three (four counting OS/2`s -Zmt/-Zst) different switches
for same thing - producing a threaded program. There should be only one
switch, I think -fthreads looks best. I think this switch should be
unified ASAP, since later changing the switch may affect much more
makefiles.

>pthread library.  Similiary, -threads would do the same thing with 
>a platform-specific threads library.  
-fthreads should define the preprocessor symbol and link agains
thread-aware C libraries, the thread library itself
can be as well linked with something like -lthreads.

Greetings,
    _\ndy@teamOS/2

Re: MT-safe exception and thread library

[Teemu Torma]

Does the following make any sense?  It should combine the existing
functionality to allow compiling with -D_PTHREADS etc, or if not
defined, uses the --enable-threads and weak symbols.

I have only tested these on Solaris 2.5, with solaris and posix
threads.   It seems to work.  The idea is to have a function
__gthread_active_p to see if threads have actually been linked in or
not. 

One dummy thing in Solaris 2.5 though.  libc defines all solaris
thread symbols (thr_*) as dummy functions.  thr_keycreate tries to
detect if a new key was actually created, and if not, return -1 so
that libgcc can fall back to static eh context.

I think someone should create all missing thread packages here,
since objc uses the same thread package names.  Also objc/thr-decosf1
seems to be same as DCE threads, so one of the names should be
changed. 

Teemu

1997-12-17  Teemu Torma  <tot@trema.com>
 
	* Makefile.in (LIBGCC2_CFLAGS): Added -DGTHREAD_FILE
	* gthr.h: New file.
	* gthr-single.h: New file.
	* gthr-posix.h: New file.
	* gthr-solaris.h: New file.
	* gthr-dce.h: New file.
	* libgcc-thr.h: Removed.
	* frame.c: Include gthr.h instead of libgcc-thr.h.
	* libgcc2.c: Include gthr.h instead of libgcc-thr.h.
	(eh_context_initialize): If __gthread_once fails, use static eh
	context. 

Index: Makefile.in
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/Makefile.in,v
retrieving revision 1.12
diff -c -c -3 -p -r1.12 Makefile.in
*** Makefile.in	1997/12/17 09:37:13	1.12
--- Makefile.in	1997/12/17 11:27:25
*************** LIBGCC2 = libgcc2.a
*** 281,287 ****
  # -fexceptions is necessary for eh.o now that the exceptions are
  # the default for g++ only.
  LIBGCC2_DEBUG_CFLAGS = -g1
! LIBGCC2_CFLAGS = -O2 $(LIBGCC2_INCLUDES) $(GCC_CFLAGS) $(TARGET_LIBGCC2_CFLAGS) $(LIBGCC2_DEBUG_CFLAGS) -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -fexceptions @inhibit_libc@ 
  
  # Additional options to use when compiling libgcc2.a.
  # Some targets override this to -Iinclude
--- 281,287 ----
  # -fexceptions is necessary for eh.o now that the exceptions are
  # the default for g++ only.
  LIBGCC2_DEBUG_CFLAGS = -g1
! LIBGCC2_CFLAGS = -O2 $(LIBGCC2_INCLUDES) $(GCC_CFLAGS) $(TARGET_LIBGCC2_CFLAGS) $(LIBGCC2_DEBUG_CFLAGS) -DGTHREAD_FILE=\"gthr-$(GCC_THREAD_FILE).h\" -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -fexceptions @inhibit_libc@ 
  
  # Additional options to use when compiling libgcc2.a.
  # Some targets override this to -Iinclude
Index: frame.c
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/frame.c,v
retrieving revision 1.13
diff -c -c -3 -p -r1.13 frame.c
*** frame.c	1997/12/17 09:37:16	1.13
--- frame.c	1997/12/17 11:08:52
*************** Boston, MA 02111-1307, USA.  */
*** 39,45 ****
  #include "dwarf2.h"
  #include <stddef.h>
  #include "frame.h"
! #include "libgcc-thr.h"
  
  #ifdef __GTHREAD_MUTEX_INIT
  static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
--- 39,45 ----
  #include "dwarf2.h"
  #include <stddef.h>
  #include "frame.h"
! #include "gthr.h"
  
  #ifdef __GTHREAD_MUTEX_INIT
  static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
Index: gthr-dce.h
===================================================================
RCS file: gthr-dce.h
diff -N gthr-dce.h
*** /dev/null	Wed Dec 17 17:25:43 1997
--- gthr-dce.h	Wed Dec 17 17:23:13 1997
***************
*** 0 ****
--- 1,143 ----
+ 
+ /* Compile this one with gcc.  */
+ /* Copyright (C) 1997 Free Software Foundation, Inc.
+ 
+ This file is part of GNU CC.
+ 
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+ 
+ GNU CC is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING.  If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.  */
+ 
+ /* As a special exception, if you link this library with other files,
+    some of which are compiled with GCC, to produce an executable,
+    this library does not by itself cause the resulting executable
+    to be covered by the GNU General Public License.
+    This exception does not however invalidate any other reasons why
+    the executable file might be covered by the GNU General Public License.  */
+ 
+ #ifndef __gthr_dce_h
+ #define __gthr_dce_h
+ 
+ /* DCE threads interface.
+    DCE threads are based on POSIX threads draft 4, and many things
+    have changed since then. */
+ 
+ #define __GTHREADS 1
+ 
+ #include <pthread.h>
+ 
+ typedef pthread_key_t __gthread_key_t;
+ typedef pthread_once_t __gthread_once_t;
+ typedef pthread_mutex_t __gthread_mutex_t;
+ 
+ #define __GTHREAD_ONCE_INIT pthread_once_init
+ /* Howto define __GTHREAD_MUTEX_INIT? */
+ 
+ #if SUPPORTS_WEAK && GTHREAD_USE_WEAK
+ 
+ #pragma weak pthread_once
+ #pragma weak pthread_once_init
+ #pragma weak pthread_key_create
+ #pragma weak pthread_key_delete
+ #pragma weak pthread_getspecific
+ #pragma weak pthread_setspecific
+ #pragma weak pthread_create
+ 
+ #pragma weak pthread_mutex_lock
+ #pragma weak pthread_mutex_trylock
+ #pragma weak pthread_mutex_unlock
+ 
+ static void *__gthread_active_ptr = &pthread_create;
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return __gthread_active_ptr != 0;
+ }
+ 
+ #else /* not SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return 1;
+ }
+ 
+ #endif /* SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_once (__gthread_once_t *once, void (*func) ())
+ {
+   if (__gthread_active_p ())
+     return pthread_once (once, func);
+   else
+     return -1;
+ }
+ 
+ static inline int
+ __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
+ {
+   return pthread_keycreate (key, dtor);
+ }
+ 
+ static inline int
+ __gthread_key_delete (__gthread_key_t key)
+ {
+   return pthread_key_delete (key);
+ }
+ 
+ static inline void *
+ __gthread_getspecific (__gthread_key_t key)
+ {
+   void *ptr;
+   if (pthread_getspecific (key, &ptr) == 0)
+     return ptr;
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_setspecific (__gthread_key_t key, const void *ptr)
+ {
+   return pthread_setspecific (key, (void *) ptr);
+ }
+ 
+ static inline int
+ __gthread_mutex_lock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_lock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_trylock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_trylock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_unlock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_unlock (mutex);
+   else
+     return 0;
+ }
+ 
+ #endif /* not __gthr_dce_h */
Index: gthr-posix.h
===================================================================
RCS file: gthr-posix.h
diff -N gthr-posix.h
*** /dev/null	Wed Dec 17 17:25:43 1997
--- gthr-posix.h	Wed Dec 17 17:22:59 1997
***************
*** 0 ****
--- 1,137 ----
+ /* Threads compatibily routines for libgcc2.  */
+ /* Compile this one with gcc.  */
+ /* Copyright (C) 1997 Free Software Foundation, Inc.
+ 
+ This file is part of GNU CC.
+ 
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+ 
+ GNU CC is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING.  If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.  */
+ 
+ /* As a special exception, if you link this library with other files,
+    some of which are compiled with GCC, to produce an executable,
+    this library does not by itself cause the resulting executable
+    to be covered by the GNU General Public License.
+    This exception does not however invalidate any other reasons why
+    the executable file might be covered by the GNU General Public License.  */
+ 
+ #ifndef __gthr_posix_h
+ #define __gthr_posix_h
+ 
+ /* POSIX threads specific definitions.
+    Easy, since the interface is just one-to-one mapping. */
+ 
+ #define __GTHREADS 1
+ 
+ #include <pthread.h>
+ 
+ typedef pthread_key_t __gthread_key_t;
+ typedef pthread_once_t __gthread_once_t;
+ typedef pthread_mutex_t __gthread_mutex_t;
+ 
+ #define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
+ #define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
+ 
+ #if SUPPORTS_WEAK && GTHREAD_USE_WEAK
+ 
+ #pragma weak pthread_once
+ #pragma weak pthread_key_create
+ #pragma weak pthread_key_delete
+ #pragma weak pthread_getspecific
+ #pragma weak pthread_setspecific
+ #pragma weak pthread_create
+ 
+ #pragma weak pthread_mutex_lock 
+ #pragma weak pthread_mutex_trylock 
+ #pragma weak pthread_mutex_unlock 
+ 
+ static void *__gthread_active_ptr = &pthread_create;
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return __gthread_active_ptr != 0;
+ }
+ 
+ #else /* not SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return 1;
+ }
+ 
+ #endif /* SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_once (__gthread_once_t *once, void (*func) ())
+ {
+   if (__gthread_active_p ())
+     return pthread_once (once, func);
+   else
+     return -1;
+ }
+ 
+ static inline int
+ __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
+ {
+   return pthread_key_create (key, dtor);
+ }
+ 
+ static inline int
+ __gthread_key_delete (__gthread_key_t key)
+ {
+   return pthread_key_delete (key);
+ }
+ 
+ static inline void *
+ __gthread_getspecific (__gthread_key_t key)
+ {
+   return pthread_getspecific (key);
+ }
+ 
+ static inline int
+ __gthread_setspecific (__gthread_key_t key, const void *ptr)
+ {
+   return pthread_setspecific (key, ptr);
+ }
+ 
+ static inline int
+ __gthread_mutex_lock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_lock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_trylock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_trylock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_unlock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return pthread_mutex_unlock (mutex);
+   else
+     return 0;
+ }
+ 
+ #endif /* not __gthr_posix_h */
Index: gthr-single.h
===================================================================
RCS file: gthr-single.h
diff -N gthr-single.h
*** /dev/null	Wed Dec 17 17:25:43 1997
--- gthr-single.h	Wed Dec 17 12:01:59 1997
***************
*** 0 ****
--- 1,62 ----
+ /* Threads compatibily routines for libgcc2.  */
+ /* Compile this one with gcc.  */
+ /* Copyright (C) 1997 Free Software Foundation, Inc.
+ 
+ This file is part of GNU CC.
+ 
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+ 
+ GNU CC is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING.  If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.  */
+ 
+ /* As a special exception, if you link this library with other files,
+    some of which are compiled with GCC, to produce an executable,
+    this library does not by itself cause the resulting executable
+    to be covered by the GNU General Public License.
+    This exception does not however invalidate any other reasons why
+    the executable file might be covered by the GNU General Public License.  */
+ 
+ #ifndef __gthr_single_h
+ #define __gthr_single_h
+ 
+ /* Just provide compatibility for mutex handling. */
+ 
+ typedef int __gthread_mutex_t;
+ 
+ #define __GTHREAD_MUTEX_INIT 0
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_lock (__gthread_mutex_t *mutex)
+ {
+   return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_trylock (__gthread_mutex_t *mutex)
+ {
+   return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_unlock (__gthread_mutex_t *mutex)
+ {
+   return 0;
+ }
+ 
+ #endif /* not __gthr_single_h */
Index: gthr-solaris.h
===================================================================
RCS file: gthr-solaris.h
diff -N gthr-solaris.h
*** /dev/null	Wed Dec 17 17:25:43 1997
--- gthr-solaris.h	Wed Dec 17 17:23:08 1997
***************
*** 0 ****
--- 1,172 ----
+ /* Threads compatibily routines for libgcc2.  */
+ /* Compile this one with gcc.  */
+ /* Copyright (C) 1997 Free Software Foundation, Inc.
+ 
+ This file is part of GNU CC.
+ 
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+ 
+ GNU CC is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING.  If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.  */
+ 
+ /* As a special exception, if you link this library with other files,
+    some of which are compiled with GCC, to produce an executable,
+    this library does not by itself cause the resulting executable
+    to be covered by the GNU General Public License.
+    This exception does not however invalidate any other reasons why
+    the executable file might be covered by the GNU General Public License.  */
+ 
+ #ifndef __gthr_solaris_h
+ #define __gthr_solaris_h
+ 
+ /* Solaris threads as found in Solaris 2.[456].
+    Actually these are Unix International (UI) threads, but I don't
+    know if anyone else implements these. */
+ 
+ #define __GTHREADS 1
+ 
+ #include <thread.h>
+ #include <errno.h>
+ 
+ typedef thread_key_t __gthread_key_t;
+ typedef struct
+ {
+   mutex_t mutex;
+   int once;
+ } __gthread_once_t;
+ typedef mutex_t __gthread_mutex_t;
+ 
+ #define __GTHREAD_ONCE_INIT { DEFAULTMUTEX, 0 }
+ #define __GTHREAD_MUTEX_INIT DEFAULTMUTEX
+ 
+ #if SUPPORTS_WEAK && GTHREAD_USE_WEAK
+ 
+ #pragma weak thr_keycreate
+ #pragma weak thr_getspecific
+ #pragma weak thr_setspecific
+ #pragma weak thr_create
+ 
+ #pragma weak mutex_lock
+ #pragma weak mutex_trylock
+ #pragma weak mutex_unlock
+ 
+ /* This will not actually work in Solaris 2.5, since libc contains
+    dummy symbols of all thr_* routines. */
+ 
+ static void *__gthread_active_ptr = &thr_create;
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return __gthread_active_ptr != 0;
+ }
+ 
+ #else /* not SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_active_p ()
+ {
+   return 1;
+ }
+ 
+ #endif /* SUPPORTS_WEAK */
+ 
+ static inline int
+ __gthread_once (__gthread_once_t *once, void (*func) ())
+ {
+   if (! __gthread_active_p ())
+     return -1;
+ 
+   if (once == 0 || func == 0)
+     {
+       errno = EINVAL;
+       return -1;
+     }
+ 
+   if (once->once == 0)
+     {
+       if (mutex_lock (&once->mutex) != 0)
+ 	return -1;
+       if (once->once == 0)
+ 	{
+ 	  (*func) ();
+ 	  once->once ++;
+ 	}
+       mutex_unlock (&once->mutex);
+     }
+   return 0;
+ }
+ 
+ static inline int
+ __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
+ {
+   /* Solaris 2.5 contains thr_* routines no-op in libc, so test if we actually
+      got a reasonable key value, and if not, fail. */
+   *key = -1;
+   if (thr_keycreate (key, dtor) == -1 || *key == -1)
+     return -1;
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_key_delete (__gthread_key_t key)
+ {
+   /* Not possible. */
+   return -1;
+ }
+ 
+ static inline void *
+ __gthread_getspecific (__gthread_key_t key)
+ {
+   void *ptr;
+   if (thr_getspecific (key, &ptr) == 0)
+     return ptr;
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_setspecific (__gthread_key_t key, const void *ptr)
+ {
+   return thr_setspecific (key, (void *) ptr);
+ }
+ 
+ static inline int
+ __gthread_mutex_lock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return mutex_lock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_trylock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return mutex_trylock (mutex);
+   else
+     return 0;
+ }
+ 
+ static inline int
+ __gthread_mutex_unlock (__gthread_mutex_t *mutex)
+ {
+   if (__gthread_active_p ())
+     return mutex_unlock (mutex);
+   else
+     return 0;
+ }
+ 
+ #endif /* not __gthr_solaris_h */
Index: gthr.h
===================================================================
RCS file: gthr.h
diff -N gthr.h
*** /dev/null	Wed Dec 17 17:25:43 1997
--- gthr.h	Wed Dec 17 17:22:47 1997
***************
*** 0 ****
--- 1,94 ----
+ /* Threads compatibily routines for libgcc2.  */
+ /* Compile this one with gcc.  */
+ /* Copyright (C) 1997 Free Software Foundation, Inc.
+ 
+ This file is part of GNU CC.
+ 
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+ 
+ GNU CC is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING.  If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.  */
+ 
+ /* As a special exception, if you link this library with other files,
+    some of which are compiled with GCC, to produce an executable,
+    this library does not by itself cause the resulting executable
+    to be covered by the GNU General Public License.
+    This exception does not however invalidate any other reasons why
+    the executable file might be covered by the GNU General Public License.  */
+ 
+ #ifndef __gthr_h
+ #define __gthr_h
+ 
+ /* If this file is compiled with threads support, it must
+        #define __GTHREADS 1
+    to indicate that threads support is present.  Also it has define
+    function 
+      int __gthread_active_p ()
+    that returns 1 if thread system is active, 0 if not.
+ 
+    The threads interface must define the following types:
+      __gthread_key_t
+      __gthread_once_t
+      __gthread_mutex_t
+ 
+    The threads interface must define the following macros:
+ 
+      __GTHREAD_ONCE_INIT
+      		to initialize __gthread_once_t
+      __GTHREAD_MUTEX_INIT
+      		to initialize __gthread_mutex_t to get a fast
+ 		non-recursive mutex.
+ 
+    The threads interface must define the following static functions:
+ 
+      int __gthread_once (__gthread_once_t *once, void (*func) ())
+ 
+      int __gthread_key_create (__gthread_key_t *keyp, void (*dtor) (void *))
+      int __gthread_key_delete (__gthread_key_t key)
+ 
+      void *__gthread_getspecific (__gthread_key_t key)
+      int __gthread_setspecific (__gthread_key_t key, const void *ptr)
+ 
+      int __gthread_mutex_lock (__gthread_mutex_t *mutex);
+      int __gthread_mutex_trylock (__gthread_mutex_t *mutex);
+      int __gthread_mutex_unlock (__gthread_mutex_t *mutex);
+ 
+    All functions returning int should return 0 on success, -1 on error.
+ 
+    Currently supported threads packages are
+      POSIX threads with -D_PTHREADS
+      DCE threads with -D_DCE_THREADS
+      Solaris/UI threads with -D_SOLARIS_THREADS
+ */
+ 
+ /* Check first for thread specific defines. */
+ #if _PTHREADS
+ #include "gthr-posix.h"
+ #elif _DCE_THREADS
+ #include "gthr-dce.h"
+ #elif _SOLARIS_THREADS
+ #include "gthr-solaris.h"
+ 
+ /* Include GTHREAD_FILE if one is defined. */
+ #elif defined (GTHREAD_FILE) && SUPPORTS_WEAK
+ #ifndef GTHREAD_USE_WEAK
+ #define GTHREAD_USE_WEAK 1
+ #endif
+ #include GTHREAD_FILE
+ 
+ /* Fallback to single thread definitions. */
+ #else
+ #include "gthr-single.h"
+ #endif
+ 
+ #endif /* not __gthr_h */
Index: libgcc-thr.h
===================================================================
RCS file: libgcc-thr.h
diff -N libgcc-thr.h
*** /tmp/cvsAAAa0047j	Wed Dec 17 17:35:18 1997
--- /dev/null	Wed Dec 17 17:25:43 1997
***************
*** 1,321 ****
- /* Threads compatibily routines for libgcc2.  */
- /* Compile this one with gcc.  */
- /* Copyright (C) 1997 Free Software Foundation, Inc.
- 
- This file is part of GNU CC.
- 
- GNU CC is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- 
- GNU CC is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- GNU General Public License for more details.
- 
- You should have received a copy of the GNU General Public License
- along with GNU CC; see the file COPYING.  If not, write to
- the Free Software Foundation, 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.  */
- 
- /* As a special exception, if you link this library with other files,
-    some of which are compiled with GCC, to produce an executable,
-    this library does not by itself cause the resulting executable
-    to be covered by the GNU General Public License.
-    This exception does not however invalidate any other reasons why
-    the executable file might be covered by the GNU General Public License.  */
- 
- #ifndef __libgcc_thr_h
- #define __libgcc_thr_h
- 
- /* If this file is compiled with threads support, it must
-        #define __GTHREADS 1
-    to indicate that threads support is present.
-    
-    The threads interface must define the following types:
-      __gthread_key_t
-      __gthread_once_t
-      __gthread_mutex_t
- 
-    The threads interface must define the following macros:
- 
-      __GTHREAD_ONCE_INIT
-      		to initialize __gthread_once_t
-      __GTHREAD_MUTEX_INIT
-      		to initialize __gthread_mutex_t to get a fast
- 		non-recursive mutex.
- 
-    The threads interface must define the following static functions:
- 
-      int __gthread_once (__gthread_once_t *once, void (*func) ())
- 
-      int __gthread_key_create (__gthread_key_t *keyp, void (*dtor) (void *))
-      int __gthread_key_delete (__gthread_key_t key)
- 
-      void *__gthread_getspecific (__gthread_key_t key)
-      int __gthread_setspecific (__gthread_key_t key, const void *ptr)
- 
-      int __gthread_mutex_lock (__gthread_mutex_t *mutex);
-      int __gthread_mutex_trylock (__gthread_mutex_t *mutex);
-      int __gthread_mutex_unlock (__gthread_mutex_t *mutex);
- 
-    All functions returning int should return 0 on success, -1 on error.
- 
-    Currently supported threads packages are
-      POSIX threads with -D_PTHREADS
-      DCE threads with -D_DCE_THREADS
-      Solaris/UI threads with -D_SOLARIS_THREADS
- */
- 
- #if _PTHREADS
- /* POSIX threads specific definitions.
-    Easy, since the interface is just one-to-one mapping. */
- 
- #define __GTHREADS 1
- 
- #include <pthread.h>
- 
- typedef pthread_key_t __gthread_key_t;
- typedef pthread_once_t __gthread_once_t;
- typedef pthread_mutex_t __gthread_mutex_t;
- 
- #define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
- #define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
- 
- static inline int
- __gthread_once (__gthread_once_t *once, void (*func) ())
- {
-   return pthread_once (once, func);
- }
- 
- static inline int
- __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
- {
-   return pthread_key_create (key, dtor);
- }
- 
- static inline int
- __gthread_key_delete (__gthread_key_t key)
- {
-   return pthread_key_delete (key);
- }
- 
- static inline void *
- __gthread_getspecific (__gthread_key_t key)
- {
-   return pthread_getspecific (key);
- }
- 
- static inline int
- __gthread_setspecific (__gthread_key_t key, const void *ptr)
- {
-   return pthread_setspecific (key, ptr);
- }
- 
- static inline int
- __gthread_mutex_lock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_lock (mutex);
- }
- 
- static inline int
- __gthread_mutex_trylock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_trylock (mutex);
- }
- 
- static inline int
- __gthread_mutex_unlock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_unlock (mutex);
- }
- 
- #elif _DCE_THREADS
- /* DCE threads interface.
-    DCE threads are based on POSIX threads draft 4, and many things
-    have changed since then. */
- 
- #define __GTHREADS 1
- 
- #include <pthread.h>
- 
- typedef pthread_key_t __gthread_key_t;
- typedef pthread_once_t __gthread_once_t;
- typedef pthread_mutex_t __gthread_mutex_t;
- 
- #define __GTHREAD_ONCE_INIT pthread_once_init
- /* Howto define __GTHREAD_MUTEX_INIT? */
- 
- static inline int
- __gthread_once (__gthread_once_t *once, void (*func) ())
- {
-   return pthread_once (once, func);
- }
- 
- static inline int
- __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
- {
-   return pthread_keycreate (key, dtor);
- }
- 
- static inline int
- __gthread_key_delete (__gthread_key_t key)
- {
-   return pthread_key_delete (key);
- }
- 
- static inline void *
- __gthread_getspecific (__gthread_key_t key)
- {
-   void *ptr;
-   if (pthread_getspecific (key, &ptr) == 0)
-     return ptr;
-   else
-     return 0;
- }
- 
- static inline int
- __gthread_setspecific (__gthread_key_t key, const void *ptr)
- {
-   return pthread_setspecific (key, (void *) ptr);
- }
- 
- static inline int
- __gthread_mutex_lock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_lock (mutex);
- }
- 
- static inline int
- __gthread_mutex_trylock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_trylock (mutex);
- }
- 
- static inline int
- __gthread_mutex_unlock (__gthread_mutex_t *mutex)
- {
-   return pthread_mutex_unlock (mutex);
- }
- 
- #elif _SOLARIS_THREADS
- /* Solaris threads as found in Solaris 2.[456].
-    Actually these are Unix International (UI) threads, but I don't
-    know if anyone else implements these. */
- 
- #define __GTHREADS 1
- 
- #include <thread.h>
- #include <errno.h>
- 
- typedef thread_key_t __gthread_key_t;
- typedef struct
- {
-   mutex_t mutex;
-   int once;
- } __gthread_once_t;
- typedef mutex_t __gthread_mutex_t;
- 
- #define __GTHREAD_ONCE_INIT { DEFAULTMUTEX, 0 }
- #define __GTHREAD_MUTEX_INIT DEFAULTMUTEX
- 
- static inline int
- __gthread_once (__gthread_once_t *once, void (*func) ())
- {
-   if (once == 0 || func == 0)
-     {
-       errno = EINVAL;
-       return -1;
-     }
- 
-   if (once->once == 0)
-     {
-       if (mutex_lock (&once->mutex) != 0)
- 	return -1;
-       if (once->once == 0)
- 	{
- 	  (*func) ();
- 	  once->once ++;
- 	}
-       mutex_unlock (&once->mutex);
-     }
-   return 0;
- }
- 
- static inline int
- __gthread_key_create (__gthread_key_t *key, void (*dtor) (void *))
- {
-   return thr_keycreate (key, dtor);
- }
- 
- static inline int
- __gthread_key_delete (__gthread_key_t key)
- {
-   /* Not possible. */
-   return -1;
- }
- 
- static inline void *
- __gthread_getspecific (__gthread_key_t key)
- {
-   void *ptr;
-   if (thr_getspecific (key, &ptr) == 0)
-     return ptr;
-   else
-     return 0;
- }
- 
- static inline int
- __gthread_setspecific (__gthread_key_t key, const void *ptr)
- {
-   return thr_setspecific (key, (void *) ptr);
- }
- 
- static inline int
- __gthread_mutex_lock (__gthread_mutex_t *mutex)
- {
-   return mutex_lock (mutex);
- }
- 
- static inline int
- __gthread_mutex_trylock (__gthread_mutex_t *mutex)
- {
-   return mutex_trylock (mutex);
- }
- 
- static inline int
- __gthread_mutex_unlock (__gthread_mutex_t *mutex)
- {
-   return mutex_unlock (mutex);
- }
- 
- #else /* no threads */
- 
- /* Just provide compatibility for mutex handling. */
- 
- typedef int __gthread_mutex_t;
- 
- #define __GTHREAD_MUTEX_INIT 0
- 
- static inline int
- __gthread_mutex_lock (__gthread_mutex_t *mutex)
- {
-   return 0;
- }
- 
- static inline int
- __gthread_mutex_trylock (__gthread_mutex_t *mutex)
- {
-   return 0;
- }
- 
- static inline int
- __gthread_mutex_unlock (__gthread_mutex_t *mutex)
- {
-   return 0;
- }
- 
- #endif /* no threads */
- 
- #endif /* not __libgcc_thr_h */
--- 0 ----
Index: libgcc2.c
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/libgcc2.c,v
retrieving revision 1.16
diff -c -c -3 -p -r1.16 libgcc2.c
*** libgcc2.c	1997/12/17 09:37:18	1.16
--- libgcc2.c	1997/12/17 11:08:48
*************** int _exit_dummy_decl = 0;	/* prevent com
*** 2962,2968 ****
  \f
  #ifdef L_eh
  
! #include "libgcc-thr.h"
  
  /* Shared exception handling support routines.  */
  
--- 2962,2968 ----
  \f
  #ifdef L_eh
  
! #include "gthr.h"
  
  /* Shared exception handling support routines.  */
  
*************** eh_context_initialize ()
*** 3091,3097 ****
  #if __GTHREADS
  
    static __gthread_once_t once = __GTHREAD_ONCE_INIT;
!   __gthread_once (&once, eh_threads_initialize);
  
  #else /* no __GTHREADS */
  
--- 3091,3101 ----
  #if __GTHREADS
  
    static __gthread_once_t once = __GTHREAD_ONCE_INIT;
!   if (__gthread_once (&once, eh_threads_initialize) == -1)
!     {
!       /* Use static version of EH context. */
!       get_eh_context = &eh_context_static;
!     }
  
  #else /* no __GTHREADS */
  

Re: MT-safe exception and thread library

[H.J. Lu]

> 
> Does the following make any sense?  It should combine the existing
> functionality to allow compiling with -D_PTHREADS etc, or if not
> defined, uses the --enable-threads and weak symbols.
> 

I will be gone for 3 weeks. I will try it when I come back.

Thanks.

H.J.

Re: MT-safe exception and thread library

[Ulrich Drepper]

Teemu Torma <tot@Trema.COM> writes:

> It is not nice to use multilibs, but I am not sure if using weak
> symbols is that straightforward.  One problem that may arise is
> that MT code should usually be compiled with some preprocessor
> options (-D_REENTRANT for example), which also changes some other 
> things, at least how "errno" is defined.

No, a corect environment must not depend on -D_REENTRANT being
defined.  This is absolutely no problem if you use glibc on an ELF
system and therefore HJ's proposal is the only acceptable for these
systems.

-- Uli
---------------.      drepper at gnu.org  ,-.   Rubensstrasse 5
Ulrich Drepper  \    ,-------------------'   \  76149 Karlsruhe/Germany
Cygnus Solutions `--' drepper at cygnus.com   `------------------------

Re: MT-safe exception and thread library

[Andrey Slepuhin]

Jason Merrill wrote:
> 
> One more thing: the flag.  How about -fthreads instead of -threads?

Or -mthreads which is already present for some targets to force
the use of thread-safe versions of libc and crt0.o.
(or -fthreads should force -mthreads?)

Andrey.

MT-safe exception and thread library

[Teemu Torma]

    From:  Jason Merrill <jason@cygnus.com>
    Date:  17 Dec 1997 02:52:12 -0800

    One more thing: the flag.  How about -fthreads instead of -threads?
    
And what if there are multiple thread libraries?  There are, at
least in Solaris 2.5.  

Personally I would prefer the flag to define all necessary pre-processor symbols and link against right libraries.  So -pthreads (or whatever
the name would be) would do the right thing in all platforms to use
pthread library.  Similiary, -threads would do the same thing with 
a platform-specific threads library.  I don't know if there are
any other standards that would deserve an own flag.

Just some random thoughts.

Teemu

Re: MT-safe exception and thread library

[Andrey Slepuhin]

Teemu Torma wrote:
> 
>     From:  hjl@lucon.org (H.J. Lu)
>     Date:  Tue, 16 Dec 1997 11:29:29 -0800 (PST)
> 
>     I am not sure if I like the multilibs for the Thread-safe EH support.
>     That may be a problem for glibc. I'd like to see an option for a
>     single libgcc.a with the the Thread-safe EH support using weak
>     symols. I think it should work with gcc on platforms with weak
>     support. We can use SUPPORTS_WEAK to detect it. It should be
>     very easy to do.
> 
> It is not nice to use multilibs, but I am not sure if using weak
> symbols is that straightforward.  One problem that may arise is
> that MT code should usually be compiled with some preprocessor
> options (-D_REENTRANT for example), which also changes some other
> things, at least how "errno" is defined.  It may or may not cause
> problems in libgcc.

I agree that using weak symbols also may cause problems, but
anyway on my AIX box (which don't support weak symbols) I have
12 (!!!) different libraries with multilib enabled, so I must
to hack configuration files manually to disable cpu-specific
libraries, so it would be better to separate thread-specific
configuration options.

Andrey.

Re: MT-safe exception and thread library

[Jason Merrill]

One more thing: the flag.  How about -fthreads instead of -threads?

Jason

MT-safe exception and thread library

[Teemu Torma]

    From:  hjl@lucon.org (H.J. Lu)
    Date:  Tue, 16 Dec 1997 11:29:29 -0800 (PST)

    I am not sure if I like the multilibs for the Thread-safe EH support.
    That may be a problem for glibc. I'd like to see an option for a
    single libgcc.a with the the Thread-safe EH support using weak
    symols. I think it should work with gcc on platforms with weak
    support. We can use SUPPORTS_WEAK to detect it. It should be
    very easy to do.
    
It is not nice to use multilibs, but I am not sure if using weak
symbols is that straightforward.  One problem that may arise is
that MT code should usually be compiled with some preprocessor
options (-D_REENTRANT for example), which also changes some other 
things, at least how "errno" is defined.  It may or may not cause
problems in libgcc.

Teemu

MT-safe exception and thread library

[H.J. Lu]

I am glad to see the Thread-safe EH support in egcs 971215. There is
already configure support for thread in libobjc.a. Can libgcc also use
it also? Basically, configure defines "thread_file", which can be
single, posix, mach, win32, solaris, irix. It shouldn't be hard to
add DCE. libgcc-thr.h can be linked to libgcc-$thread_file.h
so that --enable-threads will enable the Thread-safe EH support
and set the right thread file.

I am not sure if I like the multilibs for the Thread-safe EH support.
That may be a problem for glibc. I'd like to see an option for a
single libgcc.a with the the Thread-safe EH support using weak
symols. I think it should work with gcc on platforms with weak
support. We can use SUPPORTS_WEAK to detect it. It should be
very easy to do.

Thanks.

-- 
H.J. Lu (hjl@gnu.org)