Re: c++/6381: [PATCH] Missing assembler label

[Jason Merrill <jason@redhat.com>]

The following reply was made to PR c++/6381; it has been noted by GNATS.

From: Jason Merrill <jason@redhat.com>
To: Richard Henderson <rth@redhat.com>
Cc: gcc-patches@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: c++/6381: [PATCH] Missing assembler label
Date: Wed, 08 May 2002 14:32:40 +0100

 --=-=-=
 
 >>>>> "Richard" == Richard Henderson <rth@redhat.com> writes:
 
 > On Tue, May 07, 2002 at 04:14:22PM +0100, Jason Merrill wrote:
 >> 6381 is a regression whereby compiling with -g -O causes us to end up with
 >> an undefined reference to a static local variable because we wrote out the
 >> initializer for another variable in dwarf2out.  The simple fix is to
 >> disable the problematic code; it means that the debug info will be somewhat
 >> less useful for unexpanded constants, but is safe.
 
 > Hum.  Wouldn't it be more useful to allow at least INTEGER_CST?
 
 > Oh well, perhaps your better fix can be moved to 3.1.1.
 
 That's what I was thinking.  Here's a patch that allows a bit more; doing
 any better would require some sort of support for speculative expansion,
 and I'm not sure it would be much of a win.
 
 Bootstrapping now; will apply to the trunk when done, and to the branch
 after 3.1.  Or now, if Mark would prefer.
 
 2002-05-08  Jason Merrill  <jason@redhat.com>
 
 	* dwarf2out.c (rtl_for_decl_location): Only expand INTEGER_CST and
 	REAL_CST.
 
 
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 Content-Type: text/x-patch
 Content-Disposition: inline
 
 *** dwarf2out.c.~1~	Sun May  5 22:06:08 2002
 --- dwarf2out.c	Wed May  8 14:16:58 2002
 *************** rtl_for_decl_location (decl)
 *** 8941,8955 ****
   		  == strlen (TREE_STRING_POINTER (init)) + 1))
   	    rtl = gen_rtx_CONST_STRING (VOIDmode, TREE_STRING_POINTER (init));
   	}
 ! 
 !       if (rtl == NULL)
   	{
   	  rtl = expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
   			     EXPAND_INITIALIZER);
 ! 	  /* If expand_expr returned a MEM, we cannot use it, since
 ! 	     it won't be output, leading to unresolved symbol.  */
   	  if (rtl && GET_CODE (rtl) == MEM)
 ! 	    rtl = NULL;
   	}
       }
   
 --- 8941,8957 ----
   		  == strlen (TREE_STRING_POINTER (init)) + 1))
   	    rtl = gen_rtx_CONST_STRING (VOIDmode, TREE_STRING_POINTER (init));
   	}
 !       /* If the initializer is something that we know will expand into an
 ! 	 immediate RTL constant, expand it now.  Expanding anything else
 ! 	 tends to produce unresolved symbols; see debug/5770 and c++/6381.  */
 !       else if (TREE_CODE (DECL_INITIAL (decl)) == INTEGER_CST
 ! 	       || TREE_CODE (DECL_INITIAL (decl)) == REAL_CST)
   	{
   	  rtl = expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
   			     EXPAND_INITIALIZER);
 ! 	  /* If expand_expr returns a MEM, it wasn't immediate.  */
   	  if (rtl && GET_CODE (rtl) == MEM)
 ! 	    abort ();
   	}
       }
   
 
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