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* config/tc-xtensa.c (do_align_targets): Update comment.

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(xtensa_frob_label): Compute "freq" before possibly switching frags.
	Insert a LOOP_END frag before every loop target, and do not overload
	DESIRE_ALIGN_IF_TARGET frags with loop end information.
	(xg_assemble_vliw_tokens): Use do_align_targets.
	(xtensa_fix_target_frags): Remove code to convert a
	DESIRE_ALIGN_IF_TARGET frag to a LOOP_END frag when there is a
	negatable branch at the end of a loop.
	(frag_can_negate_branch): Delete.
This commit is contained in:
Bob Wilson 2005-03-29 00:26:00 +00:00
parent e78c98404f
commit 7b1cc37781
2 changed files with 37 additions and 77 deletions
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16
gas/ChangeLog
View file

@ -1,3 +1,16 @@
2005-03-28 Sterling Augustine <sterling@tensilica.com>
Bob Wilson <bob.wilson@acm.org>
* config/tc-xtensa.c (do_align_targets): Update comment.
(xtensa_frob_label): Compute "freq" before possibly switching frags.
Insert a LOOP_END frag before every loop target, and do not overload
DESIRE_ALIGN_IF_TARGET frags with loop end information.
(xg_assemble_vliw_tokens): Use do_align_targets.
(xtensa_fix_target_frags): Remove code to convert a
DESIRE_ALIGN_IF_TARGET frag to a LOOP_END frag when there is a
negatable branch at the end of a loop.
(frag_can_negate_branch): Delete.
2005-03-28 David Mosberger <davidm@hpl.hp.com>
H.J. Lu <hongjiu.lu@intel.com>
@ -307,7 +320,8 @@
* configure: Regenerate.
* config/obj-vms.h, config/obj-vms.c, config/vms-conf.h: Remove.
2005-03-10 Bob Wilson <bob.wilson@acm.org>
2005-03-10 Sterling Augustine <sterling@tensilica.com>
Bob Wilson <bob.wilson@acm.org>
* config/tc-xtensa.c (finish_vinsn): Include the last instruction slot
when checking if xg_resolve_literals needs to be called.

98
gas/config/tc-xtensa.c
View file

@ -1033,8 +1033,9 @@ use_transform (void)
static bfd_boolean
do_align_targets (void)
{
/* After md_end, you should be checking frag by frag, rather
than state directives. */
/* Do not use this function after md_end; just look at align_targets
instead. There is no target-align directive, so alignment is either
enabled for all frags or not done at all. */
assert (!past_xtensa_end);
return align_targets && use_transform ();
}
@ -4525,7 +4526,7 @@ update_next_frag_state (fragS *fragP)
fragS *next_fragP = fragP->fr_next;
fragS *new_target = NULL;
if (align_targets)
if (align_targets)
{
/* We are guaranteed there will be one of these... */
while (!(next_fragP->fr_type == rs_machine_dependent
@ -5077,6 +5078,8 @@ xtensa_init_fix_data (fixS *x)
void
xtensa_frob_label (symbolS *sym)
{
float freq = get_subseg_target_freq (now_seg, now_subseg);
/* Since the label was already attached to a frag associated with the
previous basic block, it now needs to be reset to the current frag. */
symbol_set_frag (sym, frag_now);
@ -5087,10 +5090,19 @@ xtensa_frob_label (symbolS *sym)
else
xtensa_add_insn_label (sym);
if (symbol_get_tc (sym)->is_loop_target
&& (get_last_insn_flags (now_seg, now_subseg)
if (symbol_get_tc (sym)->is_loop_target)
{
if ((get_last_insn_flags (now_seg, now_subseg)
& FLAG_IS_BAD_LOOPEND) != 0)
as_bad (_("invalid last instruction for a zero-overhead loop"));
as_bad (_("invalid last instruction for a zero-overhead loop"));
xtensa_set_frag_assembly_state (frag_now);
frag_var (rs_machine_dependent, 4, 4, RELAX_LOOP_END,
frag_now->fr_symbol, frag_now->fr_offset, NULL);
xtensa_set_frag_assembly_state (frag_now);
xtensa_move_labels (frag_now, 0, TRUE);
}
/* No target aligning in the absolute section. */
if (now_seg != absolute_section
@ -5098,26 +5110,10 @@ xtensa_frob_label (symbolS *sym)
&& !is_unaligned_label (sym)
&& !generating_literals)
{
float freq = get_subseg_target_freq (now_seg, now_subseg);
xtensa_set_frag_assembly_state (frag_now);
/* The only time this type of frag grows is when there is a
negatable branch that needs to be relaxed as the last
instruction in a zero-overhead loop. Because alignment frags
are so common, marking them all as possibly growing four
bytes makes any worst-case analysis appear much worse than it
is. So, we make fr_var not actually reflect the amount of
memory allocated at the end of this frag, but rather the
amount of memory this frag might grow. The "4, 0" below
allocates four bytes at the end of the frag for room to grow
if we need to relax a loop end with a NOP. Frags prior to
this one might grow to align this one, but the frag itself
won't grow unless it meets the condition above. */
#define RELAX_LOOP_END_BYTES 4
frag_var (rs_machine_dependent,
RELAX_LOOP_END_BYTES, (int) freq,
0, (int) freq,
RELAX_DESIRE_ALIGN_IF_TARGET,
frag_now->fr_symbol, frag_now->fr_offset, NULL);
xtensa_set_frag_assembly_state (frag_now);
@ -6937,7 +6933,7 @@ xg_assemble_vliw_tokens (vliw_insn *vinsn)
frag_now->fr_symbol, frag_now->fr_offset, NULL);
xtensa_set_frag_assembly_state (frag_now);
}
else if (is_branch && align_targets)
else if (is_branch && do_align_targets ())
{
assert (finish_frag);
frag_var (rs_machine_dependent,
@ -7064,11 +7060,7 @@ xtensa_cleanup_align_frags (void)
/* Re-process all of the fragments looking to convert all of the
RELAX_DESIRE_ALIGN_IF_TARGET fragments. If there is a branch
target in the next fragment, convert this to RELAX_DESIRE_ALIGN.
If the next fragment starts with a loop target, AND the previous
fragment can be expanded to negate the branch, convert this to a
RELAX_LOOP_END. Otherwise, convert to a .fill 0. */
static bfd_boolean frag_can_negate_branch (fragS *);
Otherwise, convert to a .fill 0. */
static void
xtensa_fix_target_frags (void)
@ -7079,7 +7071,6 @@ xtensa_fix_target_frags (void)
so we walk over subsections instead of sections. */
for (frchP = frchain_root; frchP; frchP = frchP->frch_next)
{
bfd_boolean prev_frag_can_negate_branch = FALSE;
fragS *fragP;
/* Walk over all of the fragments in a subsection. */
@ -7088,61 +7079,16 @@ xtensa_fix_target_frags (void)
if (fragP->fr_type == rs_machine_dependent
&& fragP->fr_subtype == RELAX_DESIRE_ALIGN_IF_TARGET)
{
if (next_frag_is_loop_target (fragP))
{
if (prev_frag_can_negate_branch)
{
fragP->fr_subtype = RELAX_LOOP_END;
/* See the comment near the frag_var with a
RELAX_DESIRE_ALIGN to see why we do this. */
fragP->fr_var = RELAX_LOOP_END_BYTES;
}
else
{
if (next_frag_is_branch_target (fragP))
fragP->fr_subtype = RELAX_DESIRE_ALIGN;
else
frag_wane (fragP);
}
}
else if (next_frag_is_branch_target (fragP))
if (next_frag_is_branch_target (fragP))
fragP->fr_subtype = RELAX_DESIRE_ALIGN;
else
frag_wane (fragP);
}
if (fragP->fr_fix != 0)
prev_frag_can_negate_branch = FALSE;
if (frag_can_negate_branch (fragP))
prev_frag_can_negate_branch = TRUE;
}
}
}
static bfd_boolean
frag_can_negate_branch (fragS *fragP)
{
xtensa_isa isa = xtensa_default_isa;
vliw_insn vinsn;
int slot;
if (fragP->fr_type != rs_machine_dependent
|| fragP->fr_subtype != RELAX_SLOTS)
return FALSE;
vinsn_from_chars (&vinsn, fragP->fr_opcode);
for (slot = 0; slot < xtensa_format_num_slots (isa, vinsn.format); slot++)
{
if ((fragP->tc_frag_data.slot_subtypes[slot] == RELAX_IMMED)
&& xtensa_opcode_is_branch (isa, vinsn.slots[slot].opcode) == 1)
return TRUE;
}
return FALSE;
}
static bfd_boolean is_narrow_branch_guaranteed_in_range (fragS *, TInsn *);
static void