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fix Xtensa labels before LOOP opcodes
- From: Bob Wilson <bwilson at tensilica dot com>
- To: binutils at sources dot redhat dot com
- Date: Fri, 30 Mar 2007 17:14:32 -0700
- Subject: fix Xtensa labels before LOOP opcodes
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);
}