dwarf2out.c patch for block extern decl abort

[Jim Wilson]

This continues the thread I started on gcc-bugs.
	http://gcc.gnu.org/ml/gcc-bugs/2000-07/msg00702.html
After some more confused poking around, I believe I have the right fix this
time.

The call to set_decl_origin_self sets DECL_ABSTRACT_ORIGIN, which is safe
only if we have a die for this decl.  However, there are cases where
gen_abstract_function decides not to emit a die.  This is because it calls
dwarf2out_decl instead of gen_decl_die, and dwarf2out_decl ignores some
cases that gen_decl_die does not.  Thus we must not execute this code
for decls that are ignored by dwarf2out_decl.  In particular, we can't
execute this code if DECL_INITIAL (decl) == NULL_TREE.

This was tested with an x86-linux --with-dwarf2 bootstrap, a make check,
and my original testcase.

I have checked in this patch.

2000-07-27  Jim Wilson  <wilson@cygnus.com>

	* dwarf2out.c (gen_decl_die): Don't call gen_abstract_function if
	DECL_INITIAL (decl) == NULL_TREE.

Index: dwarf2out.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/dwarf2out.c,v
retrieving revision 1.189
diff -p -r1.189 dwarf2out.c
*** dwarf2out.c	2000/07/26 20:59:32	1.189
--- dwarf2out.c	2000/07/28 02:11:48
*************** gen_decl_die (decl, context_die)
*** 9671,9677 ****
        /* If we're emitting an out-of-line copy of an inline function,
  	 emit info for the abstract instance and set up to refer to it.  */
        if (DECL_INLINE (decl) && ! DECL_ABSTRACT (decl)
! 	  && ! class_scope_p (context_die))
  	{
  	  gen_abstract_function (decl);
  	  set_decl_origin_self (decl);
--- 9671,9681 ----
        /* If we're emitting an out-of-line copy of an inline function,
  	 emit info for the abstract instance and set up to refer to it.  */
        if (DECL_INLINE (decl) && ! DECL_ABSTRACT (decl)
! 	  && ! class_scope_p (context_die)
! 	  /* gen_abstract_function won't emit a die if this is just a
! 	     declaration.  We must avoid setting DECL_ABSTRACT_ORIGIN in
! 	     that case, because that works only if we have a die.  */
! 	  && DECL_INITIAL (decl) != NULL_TREE)
  	{
  	  gen_abstract_function (decl);
  	  set_decl_origin_self (decl);