fix weak-5 on alpha

[Richard Henderson <rth at redhat dot com>]

This test was aborting due to a weakening after definition error.
I.e. the test case was incorrect.

I've adjusted the varasm.c widgetry to catch this.

Tested on alphaev6-linux.


r~


        * varasm.c (merge_weak): Error for any weakening after definition.
        Adjust weakening after use warning to catch more cases.
        (assemble_alias): Set TREE_USED and TREE_ASM_WRITTEN consistently.
        * config/alpha/alpha.c (alpha_encode_section_info): Do not abort.

        * gcc.dg/weak-5.c (vfoo1c): No warning here.
        (vfoo1f): Warning here.
        (vfoo1l): Don't redefine the alias.

Index: gcc/varasm.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/varasm.c,v
retrieving revision 1.273
diff -c -p -d -r1.273 varasm.c
*** gcc/varasm.c	15 May 2002 09:00:12 -0000	1.273
--- gcc/varasm.c	15 May 2002 16:42:32 -0000
*************** merge_weak (newdecl, olddecl)
*** 4830,4843 ****
    if (DECL_WEAK (newdecl) == DECL_WEAK (olddecl))
      return;
  
-   if (SUPPORTS_WEAK
-       && DECL_WEAK (newdecl) 
-       && DECL_EXTERNAL (newdecl) && DECL_EXTERNAL (olddecl)
-       && (TREE_CODE (olddecl) != VAR_DECL || ! TREE_STATIC (olddecl))
-       && TREE_USED (olddecl)
-       && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (olddecl)))
-     warning_with_decl (newdecl, "weak declaration of `%s' after first use results in unspecified behavior");
- 
    if (DECL_WEAK (newdecl))
      {
        tree wd;
--- 4830,4835 ----
*************** merge_weak (newdecl, olddecl)
*** 4848,4857 ****
  	 go back and make it weak.  This error cannot caught in
  	 declare_weak because the NEWDECL and OLDDECL was not yet
  	 been merged; therefore, TREE_ASM_WRITTEN was not set.  */
!       if (TREE_CODE (olddecl) == FUNCTION_DECL && TREE_ASM_WRITTEN (olddecl))
  	error_with_decl (newdecl, 
  			 "weak declaration of `%s' must precede definition");
!       
        if (SUPPORTS_WEAK)
  	{
  	  /* We put the NEWDECL on the weak_decls list at some point.
--- 4840,4865 ----
  	 go back and make it weak.  This error cannot caught in
  	 declare_weak because the NEWDECL and OLDDECL was not yet
  	 been merged; therefore, TREE_ASM_WRITTEN was not set.  */
!       if (TREE_ASM_WRITTEN (olddecl))
  	error_with_decl (newdecl, 
  			 "weak declaration of `%s' must precede definition");
! 
!       /* If we've already generated rtl referencing OLDDECL, we may
! 	 have done so in a way that will not function properly with
! 	 a weak symbol.  */
!       else if (TREE_USED (olddecl)
! 	       && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (olddecl))
! 	       /* ??? Not impossible that some platform may generate code
! 		  that doesn't function *at all* with incorrect declaration
! 		  before use.  However, all known at present will assume
! 		  exteral and common symbols are not "local".  */
! 	       /* ??? Probably these exceptions to the rule will just
! 		  confuse users about the true nature of the problem and
! 		  we should warn for *any* use before weakening.  */
! 	       && ! (DECL_EXTERNAL (olddecl)
! 		     || DECL_COMMON (olddecl)))
! 	warning_with_decl (newdecl, "weak declaration of `%s' after first use results in unspecified behavior");
! 
        if (SUPPORTS_WEAK)
  	{
  	  /* We put the NEWDECL on the weak_decls list at some point.
*************** assemble_alias (decl, target)
*** 4992,4998 ****
  #else
    ASM_OUTPUT_DEF (asm_out_file, name, IDENTIFIER_POINTER (target));
  #endif
-   TREE_ASM_WRITTEN (decl) = 1;
  #else /* !ASM_OUTPUT_DEF */
  #if defined (ASM_OUTPUT_WEAK_ALIAS) || defined (ASM_WEAKEN_DECL)
    if (! DECL_WEAK (decl))
--- 5000,5005 ----
*************** assemble_alias (decl, target)
*** 5003,5013 ****
  #else
    ASM_OUTPUT_WEAK_ALIAS (asm_out_file, name, IDENTIFIER_POINTER (target));
  #endif
-   TREE_ASM_WRITTEN (decl) = 1;
  #else
    warning ("alias definitions not supported in this configuration; ignored");
  #endif
  #endif
  }
  
  /* Emit an assembler directive to set symbol for DECL visibility to
--- 5010,5023 ----
  #else
    ASM_OUTPUT_WEAK_ALIAS (asm_out_file, name, IDENTIFIER_POINTER (target));
  #endif
  #else
    warning ("alias definitions not supported in this configuration; ignored");
  #endif
  #endif
+ 
+   TREE_USED (decl) = 1;
+   TREE_ASM_WRITTEN (decl) = 1;
+   TREE_ASM_WRITTEN (DECL_ASSEMBLER_NAME (decl)) = 1;
  }
  
  /* Emit an assembler directive to set symbol for DECL visibility to
Index: gcc/config/alpha/alpha.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/alpha/alpha.c,v
retrieving revision 1.246
diff -c -p -d -r1.246 alpha.c
*** gcc/config/alpha/alpha.c	5 May 2002 21:54:38 -0000	1.246
--- gcc/config/alpha/alpha.c	15 May 2002 16:42:33 -0000
*************** alpha_encode_section_info (decl, first)
*** 1678,1684 ****
        XSTR (XEXP (DECL_RTL (decl), 0), 0) = string;
      }
    else if (symbol_str[0] == '@')
!     abort ();
  }
  
  /* legitimate_address_p recognizes an RTL expression that is a valid
--- 1678,1688 ----
        XSTR (XEXP (DECL_RTL (decl), 0), 0) = string;
      }
    else if (symbol_str[0] == '@')
!     {
!       /* We're hosed.  This can happen when the user adds a weak
! 	 attribute after rtl generation.  They should have gotten
! 	 a warning about unspecified behaviour from varasm.c.  */
!     }
  }
  
  /* legitimate_address_p recognizes an RTL expression that is a valid
Index: gcc/testsuite/gcc.dg/weak-5.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/testsuite/gcc.dg/weak-5.c,v
retrieving revision 1.2
diff -c -p -d -r1.2 weak-5.c
*** gcc/testsuite/gcc.dg/weak-5.c	8 May 2002 14:37:55 -0000	1.2
--- gcc/testsuite/gcc.dg/weak-5.c	15 May 2002 16:42:33 -0000
*************** void * foo1c (void)
*** 44,50 ****
  {
    return (void *)&vfoo1c;
  }
! extern int vfoo1c __attribute__((weak)); /* { dg-warning "weak declaration" "weak declaration" } */
  
  
  extern int vfoo1d __attribute__((weak));
--- 44,50 ----
  {
    return (void *)&vfoo1c;
  }
! extern int vfoo1c __attribute__((weak));
  
  
  extern int vfoo1d __attribute__((weak));
*************** void * foo1f (void)
*** 68,74 ****
  {
    return (void *)&vfoo1f;
  }
! extern int vfoo1f __attribute__((weak));
  
  
  extern int vfoo1g;
--- 68,74 ----
  {
    return (void *)&vfoo1f;
  }
! extern int vfoo1f __attribute__((weak)); /* { dg-warning "weak declaration" "weak declaration" } */
  
  
  extern int vfoo1g;
*************** int vfoo1k = 1;
*** 111,116 ****
  
  
  int vfoox1l = 1;
- extern int vfoo1l __attribute__((alias ("vfoox1l")));
  extern int vfoo1l __attribute__((weak, alias ("vfoox1l")));
- 
--- 111,114 ----