Updated: [PATCH] further equate changes

["Jan Beulich" <JBeulich at novell dot com>]

This replaces the patch previously posted
(http://sourceware.org/ml/binutils/2005-11/msg00379.html); there is
a small adjustment needed so that transitivity (for equates of
equates) is guaranteed when resolving expressions.

This patch eliminates some more problems with equates, namely when the
target of the equates are registers, but also in a few cases when the
target is (yet) undefined.

Built and tested on i686-pc-linux-gnu, x86_64-unknown-linux-gnu,
ia64-unknown-linux-gnu, and for a large number of cross targets.

Jan

gas/
2005-11-31  Jan Beulich  <jbeulich@novell.com>

	* symbols.h (snapshot_symbol): First parameter is now pointer
	to pointer to symbolS.
	* symbols.c (snapshot_symbol): Likewise. Store resulting symbol
	there. Use symbol_equated_p.
	* expr.c (resolve_expression): Change first argument to
	snapshot_symbol. Track possibly changed add_symbol consistently
	across function. Resolve more special cases with known result.
	Also update final_val when replacing add_symbol.

gas/testsuite/
2005-11-31  Jan Beulich  <jbeulich@novell.com>

	* gas/all/cond.s: Also check .if works on equates to undefined
	when the expression value can be known without knowing the
	value of the symbol.
	* gas/all/cond.l: Adjust.
	* gas/i386/equ.s: Also check .if works on (equates to)
	registers when the expression value can be known without
	knowing the value of the register.
	* gas/i386/equ.e: Adjuust.

---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/expr.c	2005-11-09
15:40:05.000000000 +0100
+++ 2005-11-24/gas/expr.c	2005-11-30 16:41:12.216694560 +0100
@@ -1913,7 +1913,7 @@ resolve_expression (expressionS *express
 
     case O_symbol:
     case O_symbol_rva:
-      if (!snapshot_symbol (add_symbol, &left, &seg_left,
&frag_left))
+      if (!snapshot_symbol (&add_symbol, &left, &seg_left,
&frag_left))
 	return 0;
 
       break;
@@ -1921,7 +1921,7 @@ resolve_expression (expressionS *express
     case O_uminus:
     case O_bit_not:
     case O_logical_not:
-      if (!snapshot_symbol (add_symbol, &left, &seg_left,
&frag_left))
+      if (!snapshot_symbol (&add_symbol, &left, &seg_left,
&frag_left))
 	return 0;
 
       if (seg_left != absolute_section)
@@ -1955,8 +1955,8 @@ resolve_expression (expressionS *express
     case O_gt:
     case O_logical_and:
     case O_logical_or:
-      if (!snapshot_symbol (add_symbol, &left, &seg_left, &frag_left)
-	  || !snapshot_symbol (op_symbol, &right, &seg_right,
&frag_right))
+      if (!snapshot_symbol (&add_symbol, &left, &seg_left,
&frag_left)
+	  || !snapshot_symbol (&op_symbol, &right, &seg_right,
&frag_right))
 	return 0;
 
       /* Simplify addition or subtraction of a constant by folding
the
@@ -1974,7 +1974,7 @@ resolve_expression (expressionS *express
 	      final_val += left;
 	      left = right;
 	      seg_left = seg_right;
-	      expressionP->X_add_symbol = expressionP->X_op_symbol;
+	      add_symbol = op_symbol;
 	      op = O_symbol;
 	      break;
 	    }
@@ -1991,9 +1991,17 @@ resolve_expression (expressionS *express
 
       /* Equality and non-equality tests are permitted on anything.
 	 Subtraction, and other comparison operators are permitted if
-	 both operands are in the same section.  Otherwise, both
-	 operands must be absolute.  We already handled the case of
-	 addition or subtraction of a constant above.  */
+	 both operands are in the same section.
+	 Shifts by constant zero are permitted on anything.
+	 Multiplies, bit-ors, and bit-ands with constant zero are
+	 permitted on anything.
+	 Multiplies and divides by constant one are permitted on
+	 anything.
+	 Binary operations with both operands being the same register
+	 or undefined symbol are permitted if the result doesn't depend
+	 on the input value.
+	 Otherwise, both operands must be absolute.  We already handled
+	 the case of addition or subtraction of a constant above.  */
       if (!(seg_left == absolute_section
 	       && seg_right == absolute_section)
 	  && !(op == O_eq || op == O_ne)
@@ -2001,10 +2009,64 @@ resolve_expression (expressionS *express
 		|| op == O_lt || op == O_le || op == O_ge || op ==
O_gt)
 	       && seg_left == seg_right
 	       && (finalize_syms || frag_left == frag_right)
-	       && ((seg_left != undefined_section
-		    && seg_left != reg_section)
-		   || add_symbol == op_symbol)))
-	return 0;
+	       && (seg_left != reg_section || left == right)
+	       && (seg_left != undefined_section || add_symbol ==
op_symbol)))
+	{
+	  if ((seg_left == absolute_section && left == 0)
+	      || (seg_right == absolute_section && right == 0))
+	    {
+	      if (op == O_bit_exclusive_or || op == O_bit_inclusive_or)
+		{
+		  if (seg_right != absolute_section || right != 0)
+		    {
+		      seg_left = seg_right;
+		      left = right;
+		      add_symbol = op_symbol;
+		    }
+		  op = O_symbol;
+		  break;
+		}
+	      else if (op == O_left_shift || op == O_right_shift)
+		{
+		  if (seg_left != absolute_section || left != 0)
+		    {
+		      op = O_symbol;
+		      break;
+		    }
+		}
+	      else if (op != O_multiply
+		       && op != O_bit_or_not && op != O_bit_and)
+	        return 0;
+	    }
+	  else if (op == O_multiply
+		   && seg_left == absolute_section && left == 1)
+	    {
+	      seg_left = seg_right;
+	      left = right;
+	      add_symbol = op_symbol;
+	      op = O_symbol;
+	      break;
+	    }
+	  else if ((op == O_multiply || op == O_divide)
+		   && seg_right == absolute_section && right == 1)
+	    {
+	      op = O_symbol;
+	      break;
+	    }
+	  else if (left != right
+		   || ((seg_left != reg_section || seg_right !=
reg_section)
+		       && (seg_left != undefined_section
+			   || seg_right != undefined_section
+			   || add_symbol != op_symbol)))
+	    return 0;
+	  else if (op == O_bit_and || op == O_bit_inclusive_or)
+	    {
+	      op = O_symbol;
+	      break;
+	    }
+	  else if (op != O_bit_exclusive_or && op != O_bit_or_not)
+	    return 0;
+	}
 
       switch (op)
 	{
@@ -2032,8 +2094,7 @@ resolve_expression (expressionS *express
 	  left = (left == right
 		  && seg_left == seg_right
 		  && (finalize_syms || frag_left == frag_right)
-		  && ((seg_left != undefined_section
-		       && seg_left != reg_section)
+		  && (seg_left != undefined_section
 		      || add_symbol == op_symbol)
 		  ? ~ (valueT) 0 : 0);
 	  if (op == O_ne)
@@ -2066,6 +2127,9 @@ resolve_expression (expressionS *express
 	op = O_constant;
       else if (seg_left == reg_section && final_val == 0)
 	op = O_register;
+      else if (add_symbol != expressionP->X_add_symbol)
+	final_val += left;
+      expressionP->X_add_symbol = add_symbol;
     }
   expressionP->X_op = op;
 
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/symbols.c	2005-11-16
09:44:49.000000000 +0100
+++ 2005-11-24/gas/symbols.c	2005-11-24 16:57:17.000000000 +0100
@@ -1354,8 +1354,10 @@ resolve_local_symbol_values (void)
    sub-expressions used.  */
 
 int
-snapshot_symbol (symbolS *symbolP, valueT *valueP, segT *segP, fragS
**fragPP)
+snapshot_symbol (symbolS **symbolPP, valueT *valueP, segT *segP, fragS
**fragPP)
 {
+  symbolS *symbolP = *symbolPP;
+
   if (LOCAL_SYMBOL_CHECK (symbolP))
     {
       struct local_symbol *locsym = (struct local_symbol *) symbolP;
@@ -1384,10 +1386,7 @@ snapshot_symbol (symbolS *symbolP, value
 	    {
 	    case O_constant:
 	    case O_register:
-	      /* This check wouldn't be needed if pseudo_set() didn't
set
-		 symbols equated to bare symbols to undefined_section. 
*/
-	      if (symbolP->bsym->section != undefined_section
-		  || symbolP->sy_value.X_op != O_symbol)
+	      if (!symbol_equated_p (symbolP))
 		break;
 	      /* Fall thru.  */
 	    case O_symbol:
@@ -1399,6 +1398,7 @@ snapshot_symbol (symbolS *symbolP, value
 	    }
 	}
 
+      *symbolPP = symbolP;
       *valueP = expr.X_add_number;
       *segP = symbolP->bsym->section;
       *fragPP = symbolP->sy_frag;
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/symbols.h	2005-11-10
10:53:51.000000000 +0100
+++ 2005-11-24/gas/symbols.h	2005-11-24 16:54:58.000000000 +0100
@@ -61,7 +61,7 @@ void symbol_print_statistics (FILE *);
 void symbol_table_insert (symbolS * symbolP);
 valueT resolve_symbol_value (symbolS *);
 void resolve_local_symbol_values (void);
-int snapshot_symbol (symbolS *, valueT *, segT *, fragS **);
+int snapshot_symbol (symbolS **, valueT *, segT *, fragS **);
 
 void print_symbol_value (symbolS *);
 void print_expr (expressionS *);
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/testsuite/gas/all/cond.l	2005-11-11
13:44:02.000000000 +0100
+++ 2005-11-24/gas/testsuite/gas/all/cond.l	2005-11-24
13:57:09.000000000 +0100
@@ -27,13 +27,32 @@
 [ 	]*[1-9][0-9]*[ 	]+\.comm[ 	]+c,[ 	]*1[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+\.ifndef[ 	]+c[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
-[ 	]*[1-9][0-9]*[ 	]+
-[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+x,[ 	]*y[ 	]*
-[ 	]*[1-9][0-9]*[ 	]+\.ifndef[ 	]+x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+x[ 	]*<>[ 	]*x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+y,[ 	]*x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.ifndef[ 	]+y[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+x[ 	]*<>[ 	]*y[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+z,[ 	]*x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+y[ 	]*<>[ 	]*z[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+a,[ 	]*y[ 	]*\+[ 	]*1[
	]*
+[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+b,[ 	]*z[ 	]*-[ 	]*1[
	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+a[ 	]*==[ 	]*x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+a[ 	]*-[ 	]*1[ 	]*<>[
	]*x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+a[ 	]*<>[ 	]*b[ 	]*\+[
	]*2[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+a[ 	]*-[ 	]*b[ 	]*<>[
	]*2[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
-[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+y,[ 	]*0[ 	]*
-[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+x[ 	]*
-[ 	]*[1-9][0-9]*[ 	]+\.elseif[ 	]+x[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.equiv[ 	]+x,[ 	]*0[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.if[ 	]+y[ 	]*
+[ 	]*[1-9][0-9]*[ 	]+\.elseif[ 	]+y[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+\.endif[ 	]*
 [ 	]*[1-9][0-9]*[ 	]+
 [ 	]*[1-9][0-9]*[ 	]+\.macro[ 	]+m[ 	]+x,[ 	]*y[ 	]*
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/testsuite/gas/all/cond.s	2005-11-11
13:40:54.000000000 +0100
+++ 2005-11-24/gas/testsuite/gas/all/cond.s	2005-11-24
13:50:46.000000000 +0100
@@ -35,14 +35,40 @@
 	.err
 	.endif
 
-	.equiv	x, y
-	.ifndef x
+	.if	x <> x
 	.err
 	.endif
-	.equiv	y, 0
-	.if	x
+	.equiv	y, x
+	.ifndef	y
 	.err
-	.elseif	x
+	.endif
+	.if	x <> y
+	.err
+	.endif
+	.equiv	z, x
+	.if	y <> z
+	.err
+	.endif
+
+	.equiv	a, y + 1
+	.equiv	b, z - 1
+	.if	a == x
+	.err
+	.endif
+	.if	a - 1 <> x
+	.err
+	.endif
+	.if	a <> b + 2
+	.err
+	.endif
+	.if	a - b <> 2
+	.err
+	.endif
+
+	.equiv	x, 0
+	.if	y
+	.err
+	.elseif	y
 	.err
 	.endif
 
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/testsuite/gas/i386/equ.e	2005-10-21
15:43:51.000000000 +0200
+++ 2005-11-24/gas/testsuite/gas/i386/equ.e	2005-11-24
15:23:14.000000000 +0100
@@ -1,2 +1,2 @@
 .*: Assembler messages:
-.*:23: Warning: Treating .* as memory reference
+.*:30: Warning: Treating .* as memory reference
---
/home/jbeulich/src/binutils/mainline/2005-11-24/gas/testsuite/gas/i386/equ.s	2005-10-27
15:33:57.000000000 +0200
+++ 2005-11-24/gas/testsuite/gas/i386/equ.s	2005-11-24
16:55:10.000000000 +0100
@@ -16,6 +16,13 @@ _start:
  .equ x, %st(1)
 	fadd	x
 
+ .if r <> %ecx
+ .err
+ .endif
+ .if r == s
+ .err
+ .endif
+
  .intel_syntax noprefix
  .equ r, -2
  .equ s, -2
@@ -33,5 +40,12 @@ _start:
  .equ x, st(7)
 	fadd	x
 
+ .if s <> gs
+ .err
+ .endif
+ .if s == x
+ .err
+ .endif
+
  .equ r, -3
  .equ s, -3

Attachment: binutils-mainline-reg-equate.patch
Description: Text document