Patch: Dwarf2 reader -vs- DW_OP_piece

[Tom Tromey <tromey@redhat.com>]

I just submitted a change that changes gcc's Dwarf-2 output.
It hasn't been approved yet, but of course I'm hoping it will be.
With this change gcc will now generate DW_OP_piece when a value spans
multiple registers.

I came up with a somewhat hacky gdb patch to ignore DW_OP_piece.

I'm hoping this patch is just a stopgap until someone adds real
Dwarf-2 location expression support to gdb.

Ok?

Tom


Index: ChangeLog
from  Tom Tromey  <tromey@redhat.com>

	* dwarf2read.c (decode_locdesc): Recognize DW_OP_piece.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.48
diff -u -r1.48 dwarf2read.c
--- dwarf2read.c 2002/02/15 22:42:33 1.48
+++ dwarf2read.c 2002/02/21 18:49:43
@@ -5808,6 +5808,7 @@
   int stacki;
   unsigned int bytes_read, unsnd;
   unsigned char op;
+  int last_was_piece = 0;
 
   i = 0;
   stacki = 0;
@@ -5891,8 +5892,13 @@
 	case DW_OP_reg29:
 	case DW_OP_reg30:
 	case DW_OP_reg31:
-	  isreg = 1;
-	  stack[++stacki] = op - DW_OP_reg0;
+	  if (last_was_piece)
+	    last_was_piece = 0;
+	  else
+	    {
+	      isreg = 1;
+	      stack[++stacki] = op - DW_OP_reg0;
+	    }
 	  break;
 
 	case DW_OP_regx:
@@ -6043,6 +6049,14 @@
 	     this using GDB's address_class enum.  */
 	  if (i < size)
 	    complain (&dwarf2_complex_location_expr);
+	  break;
+
+	case DW_OP_piece:
+	  /* For now we essentially ignore this.  We assume it only
+	     occurs when a value spans multiple registers.  */
+	  read_unsigned_leb128 (NULL, (data + i), &bytes_read);
+	  i += bytes_read;
+	  last_was_piece = 1;
 	  break;
 
 	default: