Re: PATCH: PR 857: Disallow local symbol set to undefined symbol

["H. J. Lu" <hjl at lucon dot org>]

On Tue, Apr 19, 2005 at 02:21:05PM -0700, H. J. Lu wrote:
> We shouldn't allow local symbol set to undefined symbol. Also we
> don't allow
> 
>         .set    bar,foo
>         .comm   foo,4,4
> 
> But allow
> 
>         .comm   foo,4,4
>         .set    bar,foo
> 
> This patch fixes those bugs.
> 
> 
> H.J.
> ----
> 2005-04-19  H.J. Lu  <hongjiu.lu@intel.com>
> 
> 	* read.c (pseudo_set): Disallow symbol set to common symbol.
> 
> 	* write.c (write_object_file): Report common symbol name when
> 	disallowing symbol set to common symbol. Call S_IS_EXTERNAL
> 	instead of S_IS_EXTERN.
> 
> 	PR 857
> 	* write.c (adjust_reloc_syms): Disallow local symbol set to
> 	undefined symbol.
> 

We need to allow fake label set to undefined symbol. Make `x' and `y'
global makes no difference in the output. It just makes people aware
that `x' and `y' won't be local.



H.J.
---
gas/

2005-04-19  H.J. Lu  <hongjiu.lu@intel.com>

	* config/obj-multi.h (FAKE_LABEL_NAME): Defined.

	* read.c (pseudo_set): Disallow symbol set to common symbol.

	* write.c (write_object_file): Report common symbol name when
	disallowing symbol set to common symbol. Call S_IS_EXTERNAL
	instead of S_IS_EXTERN.

	PR 857
	* write.c (adjust_reloc_syms): Disallow local symbol set to
	undefined symbol.

gas/testsuite/

2005-04-19  H.J. Lu  <hongjiu.lu@intel.com>

	* gas/all/assign.s: Make `x' and `y' global.

--- gas/config/obj-multi.h.set	2005-03-03 09:21:24.000000000 -0800
+++ gas/config/obj-multi.h	2005-04-19 15:38:38.000000000 -0700
@@ -146,6 +146,8 @@
 
 #define EMIT_SECTION_SYMBOLS (this_format->emit_section_symbols)
 
+#define FAKE_LABEL_NAME (this_emulation->fake_label_name)
+
 #ifdef OBJ_MAYBE_ELF
 /* We need OBJ_SYMFIELD_TYPE so that symbol_get_obj is defined in symbol.c
    We also need various STAB defines for stab.c  */
--- gas/read.c.set	2005-04-11 08:54:47.000000000 -0700
+++ gas/read.c	2005-04-19 14:47:23.000000000 -0700
@@ -3299,6 +3299,10 @@ pseudo_set (symbolS *symbolP)
 	{
 	  symbolS *s = exp.X_add_symbol;
 
+	  if (S_IS_COMMON (s))
+	    as_bad (_("`%s' can't be equated to common symbol '%s'"),
+		    S_GET_NAME (symbolP), S_GET_NAME (s));
+
 	  S_SET_SEGMENT (symbolP, seg);
 	  S_SET_VALUE (symbolP, exp.X_add_number + S_GET_VALUE (s));
 	  symbol_set_frag (symbolP, symbol_get_frag (s));
--- gas/testsuite/gas/all/assign.s.set	2005-04-15 08:44:24.000000000 -0700
+++ gas/testsuite/gas/all/assign.s	2005-04-19 15:00:33.000000000 -0700
@@ -1,7 +1,9 @@
+ .global x
  x = zzz
  x = x+1
  .long x
 
+ .global y
  y = 1
  y = y+zzz
  .long y
--- gas/write.c.set	2005-03-03 09:21:19.000000000 -0800
+++ gas/write.c	2005-04-19 15:55:26.000000000 -0700
@@ -787,12 +787,20 @@ adjust_reloc_syms (bfd *abfd ATTRIBUTE_U
 	if (fixp->fx_subsy != NULL)
 	  resolve_symbol_value (fixp->fx_subsy);
 
-	/* If this symbol is equated to an undefined symbol, convert
-           the fixup to being against that symbol.  */
+	/* If this symbol is equated to an undefined or common symbol,
+	   convert the fixup to being against that symbol.  */
 	if (symbol_equated_reloc_p (sym))
 	  {
+	    symbolS *new_sym
+	      = symbol_get_value_expression (sym)->X_add_symbol;
+	    const char *name = S_GET_NAME (sym);
+	    if (!S_IS_COMMON (new_sym)
+		&& strcmp (name, FAKE_LABEL_NAME)
+		&& (!S_IS_EXTERNAL (sym) || S_IS_LOCAL (sym)))
+	      as_bad (_("Local symbol `%s' can't be equated to undefined symbol `%s'"),
+		      name, S_GET_NAME (new_sym));
 	    fixp->fx_offset += symbol_get_value_expression (sym)->X_add_number;
-	    sym = symbol_get_value_expression (sym)->X_add_symbol;
+	    sym = new_sym;
 	    fixp->fx_addsy = sym;
 	  }
 
@@ -1928,8 +1936,12 @@ write_object_file (void)
 	  if (symbol_equated_reloc_p (symp))
 	    {
 	      if (S_IS_COMMON (symp))
-		as_bad (_("`%s' can't be equated to common symbol"),
-			S_GET_NAME (symp));
+		{
+		  symbolS *c
+		    = symbol_get_value_expression (symp)->X_add_symbol;
+		  as_bad (_("`%s' can't be equated to common symbol `%s'"),
+			  S_GET_NAME (symp), S_GET_NAME (c));
+		}
 	      symbol_remove (symp, &symbol_rootP, &symbol_lastP);
 	      continue;
 	    }
@@ -1956,10 +1968,10 @@ write_object_file (void)
 	  if (symp == abs_section_sym
 	      || (! EMIT_SECTION_SYMBOLS
 		  && symbol_section_p (symp))
-	      /* Note that S_IS_EXTERN and S_IS_LOCAL are not always
+	      /* Note that S_IS_EXTERNAL and S_IS_LOCAL are not always
 		 opposites.  Sometimes the former checks flags and the
 		 latter examines the name...  */
-	      || (!S_IS_EXTERN (symp)
+	      || (!S_IS_EXTERNAL (symp)
 		  && (punt || S_IS_LOCAL (symp))
 		  && ! symbol_used_in_reloc_p (symp)))
 	    {