971225: MT fixes for Solaris 2.6.

[Teemu Torma <tot at trema dot com>]

It seems that Solaris 2.6 has dummy pthread routines in libc.
pthread_once returns success but does nothing.  Here are some patches
to make sure that __gthread_once really called the initialization
routine.  I also fixed some inconsistencies in return value handling
and checking.

Teemu

1998-01-06  Teemu Torma  <tot@trema.com>

	* gthr.h: Changed the comment about return values.
	
	* gthr-solaris.h (__gthread_once): Do not use errno; return the
	error number instead of -1. 
	(__gthread_key_create): Any non-zero return value is an error.

	* libgcc2.c (eh_context_initialize): Check for non-zero return
	value from __gthread_once.
	Check that the value of get_eh_context was really changed.

Index: gthr-solaris.h
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/gthr-solaris.h,v
retrieving revision 1.2
diff -c -c -3 -p -r1.2 gthr-solaris.h
*** gthr-solaris.h	1997/12/18 12:38:09	1.2
--- gthr-solaris.h	1998/01/06 13:00:03
*************** __gthread_once (__gthread_once_t *once, 
*** 88,102 ****
      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) ();
--- 88,100 ----
      return -1;
  
    if (once == 0 || func == 0)
!     return EINVAL;
  
    if (once->once == 0)
      {
!       int status = mutex_lock (&once->mutex);
!       if (status != 0)
! 	return status;
        if (once->once == 0)
  	{
  	  (*func) ();
*************** __gthread_key_create (__gthread_key_t *k
*** 113,119 ****
    /* 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;
--- 111,117 ----
    /* 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) != 0 || *key == -1)
      return -1;
    else
      return 0;
Index: gthr.h
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/gthr.h,v
retrieving revision 1.3
diff -c -c -3 -p -r1.3 gthr.h
*** gthr.h	1997/12/18 12:38:09	1.3
--- gthr.h	1998/01/06 13:05:33
*************** Boston, MA 02111-1307, USA.  */
*** 65,71 ****
       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
--- 65,72 ----
       int __gthread_mutex_trylock (__gthread_mutex_t *mutex);
       int __gthread_mutex_unlock (__gthread_mutex_t *mutex);
  
!    All functions returning int should return zero on success or the error
!    number.  If the operation is not supported, -1 is returned.
  
     Currently supported threads packages are
       POSIX threads with -D_PTHREADS
Index: libgcc2.c
===================================================================
RCS file: /trema/cvs/gnu/egcs/gcc/libgcc2.c,v
retrieving revision 1.19
diff -c -c -3 -p -r1.19 libgcc2.c
*** libgcc2.c	1998/01/05 12:12:35	1.19
--- libgcc2.c	1998/01/06 13:11:50
*************** eh_context_initialize ()
*** 3095,3101 ****
  #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;
--- 3095,3105 ----
  #if __GTHREADS
  
    static __gthread_once_t once = __GTHREAD_ONCE_INIT;
!   /* Make sure that get_eh_context does not point to us anymore.
!      Some systems have dummy thread routines in their libc that
!      return a success (Solaris 2.6 for example). */
!   if (__gthread_once (&once, eh_threads_initialize) != 0
!       || get_eh_context == &eh_context_initialize)
      {
        /* Use static version of EH context. */
        get_eh_context = &eh_context_static;