fix Xtensa labels before LOOP opcodes

[Bob Wilson <bwilson at tensilica dot com>]

I've committed this patch to fix a problem with the Xtensa port of GAS.  The 
previous code tried to optimize the position of a label when a no-op is inserted 
to fix the alignment of a LOOP opcode.  If the LOOP was the first instruction in 
a function, the label for the function was getting moved before literal values 
stored in the text.  With this patch, GAS is more conservative and doesn't try 
to move the label before a LOOP.  Tested with an xtensa-elf target.

2007-03-30  Sterling Augustine  <sterling@tensilica.com>
	    Bob Wilson  <bob.wilson@acm.org>

gas/
	* config/tc-xtensa.c (xtensa_move_labels): Remove loops_ok argument.
	Do not check is_loop_target flag.
	(xtensa_frob_label): Adjust calls to xtensa_move_labels.
	(xg_assemble_vliw_tokens): Likewise.  Also avoid calling
	xtensa_move_labels for alignment of loop opcodes.

Index: config/tc-xtensa.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-xtensa.c,v
retrieving revision 1.78
diff -u -p -r1.78 tc-xtensa.c
--- config/tc-xtensa.c	26 Mar 2007 23:01:46 -0000	1.78
+++ config/tc-xtensa.c	30 Mar 2007 23:11:23 -0000
@@ -959,43 +959,16 @@ xtensa_clear_insn_labels (void)
 }
 
 
-/* The "loops_ok" argument is provided to allow ignoring labels that
-   define loop ends.  This fixes a bug where the NOPs to align a
-   loop opcode were included in a previous zero-cost loop:
-
-   loop a0, loopend
-     <loop1 body>
-   loopend:
-
-   loop a2, loopend2
-     <loop2 body>
-
-   would become:
-
-   loop a0, loopend
-     <loop1 body>
-     nop.n <===== bad!
-   loopend:
-
-   loop a2, loopend2
-     <loop2 body>
-
-   This argument is used to prevent moving the NOP to before the
-   loop-end label, which is what you want in this special case.  */
-
 static void
-xtensa_move_labels (fragS *new_frag, valueT new_offset, bfd_boolean loops_ok)
+xtensa_move_labels (fragS *new_frag, valueT new_offset)
 {
   sym_list *lit;
 
   for (lit = insn_labels; lit; lit = lit->next)
     {
       symbolS *lit_sym = lit->sym;
-      if (loops_ok || ! symbol_get_tc (lit_sym)->is_loop_target)
-	{
-	  S_SET_VALUE (lit_sym, new_offset);
-	  symbol_set_frag (lit_sym, new_frag);
-	}
+      S_SET_VALUE (lit_sym, new_offset);
+      symbol_set_frag (lit_sym, new_frag);
     }
 }
 
@@ -5035,7 +5008,7 @@ xtensa_frob_label (symbolS *sym)
 		frag_now->fr_symbol, frag_now->fr_offset, NULL);
 
       xtensa_set_frag_assembly_state (frag_now);
-      xtensa_move_labels (frag_now, 0, TRUE);
+      xtensa_move_labels (frag_now, 0);
     }
 
   /* No target aligning in the absolute section.  */
@@ -5051,7 +5024,7 @@ xtensa_frob_label (symbolS *sym)
 		RELAX_DESIRE_ALIGN_IF_TARGET,
 		frag_now->fr_symbol, frag_now->fr_offset, NULL);
       xtensa_set_frag_assembly_state (frag_now);
-      xtensa_move_labels (frag_now, 0, TRUE);
+      xtensa_move_labels (frag_now, 0);
     }
 
   /* We need to mark the following properties even if we aren't aligning.  */
@@ -6734,15 +6707,13 @@ xg_assemble_vliw_tokens (vliw_insn *vins
 	frag_var (rs_machine_dependent, 0, 0,
 		  RELAX_CHECK_ALIGN_NEXT_OPCODE, target_sym, 0, NULL);
       xtensa_set_frag_assembly_state (frag_now);
-
-      xtensa_move_labels (frag_now, 0, FALSE);
     }
 
   if (vinsn->slots[0].opcode == xtensa_entry_opcode
       && !vinsn->slots[0].is_specific_opcode)
     {
       xtensa_mark_literal_pool_location ();
-      xtensa_move_labels (frag_now, 0, TRUE);
+      xtensa_move_labels (frag_now, 0);
       frag_var (rs_align_test, 1, 1, 0, NULL, 2, NULL);
     }