Commit cd665a94 authored by Max Filippov's avatar Max Filippov

gas: xtensa: limit size of auto litpools

Literal movement code may grow auto litpool so big that it won't be
possible to jump around it. Limit the size of auto litpools by 1/2 of
the jump range.

gas/
2018-02-20  Max Filippov  <jcmvbkbc@gmail.com>

	* config/tc-xtensa.c (struct litpool_frag): Add new field
	literal_count.
	(MAX_AUTO_POOL_LITERALS, MAX_EXPLICIT_POOL_LITERALS)
	(MAX_POOL_LITERALS): New macro definitions.
	(auto_litpool_limit): Initialize to 0.
	(md_parse_option): Set auto_litpool_limit in the presence of
	--auto-litpools option.
	(xtensa_maybe_create_literal_pool_frag): Zero-initialize
	literal_count field.
	(xg_find_litpool): New function. Make sure that found literal
	pool size is within the limit.
	(xtensa_move_literals): Extract literal pool search code into
	the new function.
	* testsuite/gas/xtensa/all.exp: Add auto-litpools-2 test.
	* testsuite/gas/xtensa/auto-litpools-2.d: New file.
	* testsuite/gas/xtensa/auto-litpools-2.s: New file.
	* testsuite/gas/xtensa/auto-litpools.d: Fix up changed
	addresses.
	* testsuite/gas/xtensa/auto-litpools.s: Change literal value so
	that objdump doesn't get out of sync.
parent 7104e59b
2018-02-20 Max Filippov <jcmvbkbc@gmail.com>
* config/tc-xtensa.c (struct litpool_frag): Add new field
literal_count.
(MAX_AUTO_POOL_LITERALS, MAX_EXPLICIT_POOL_LITERALS)
(MAX_POOL_LITERALS): New macro definitions.
(auto_litpool_limit): Initialize to 0.
(md_parse_option): Set auto_litpool_limit in the presence of
--auto-litpools option.
(xtensa_maybe_create_literal_pool_frag): Zero-initialize
literal_count field.
(xg_find_litpool): New function. Make sure that found literal
pool size is within the limit.
(xtensa_move_literals): Extract literal pool search code into
the new function.
* testsuite/gas/xtensa/all.exp: Add auto-litpools-2 test.
* testsuite/gas/xtensa/auto-litpools-2.d: New file.
* testsuite/gas/xtensa/auto-litpools-2.s: New file.
* testsuite/gas/xtensa/auto-litpools.d: Fix up changed
addresses.
* testsuite/gas/xtensa/auto-litpools.s: Change literal value so
that objdump doesn't get out of sync.
2018-02-20 Thomas Preud'homme <thomas.preudhomme@arm.com>
* doc/c-arm.texi (.arch_extension): Mention extensions it accepts are
......
......@@ -438,6 +438,7 @@ struct litpool_frag
addressT addr;
short priority; /* 1, 2, or 3 -- 1 is highest */
short original_priority;
int literal_count;
};
/* Map a segment to its litpool_frag list. */
......@@ -451,6 +452,14 @@ struct litpool_seg
static struct litpool_seg litpool_seg_list;
/* Limit maximal size of auto litpool by half of the j range. */
#define MAX_AUTO_POOL_LITERALS 16384
/* Limit maximal size of explicit literal pool by l32r range. */
#define MAX_EXPLICIT_POOL_LITERALS 65536
#define MAX_POOL_LITERALS \
(auto_litpools ? MAX_AUTO_POOL_LITERALS : MAX_EXPLICIT_POOL_LITERALS)
/* Directive functions. */
......@@ -488,7 +497,7 @@ static int init_trampoline_frag (fragS *);
static fixS *xg_append_jump (fragS *fragP, symbolS *sym, offsetT offset);
static void xtensa_maybe_create_literal_pool_frag (bfd_boolean, bfd_boolean);
static bfd_boolean auto_litpools = FALSE;
static int auto_litpool_limit = 10000;
static int auto_litpool_limit = 0;
/* Alignment Functions. */
......@@ -984,6 +993,8 @@ md_parse_option (int c, const char *arg)
case option_auto_litpools:
auto_litpools = TRUE;
use_literal_section = FALSE;
if (auto_litpool_limit <= 0)
auto_litpool_limit = MAX_AUTO_POOL_LITERALS / 2;
return 1;
case option_no_auto_litpools:
......@@ -7912,6 +7923,7 @@ xtensa_maybe_create_literal_pool_frag (bfd_boolean create,
lpf->fragP = fragP;
lpf->priority = (needed) ? (only_if_needed) ? 3 : 2 : 1;
lpf->original_priority = lpf->priority;
lpf->literal_count = 0;
lps->frag_count = 0;
}
......@@ -11188,6 +11200,66 @@ xg_promote_candidate_litpool (struct litpool_seg *lps,
/* Rest is done in xtensa_relax_frag. */
}
static struct litpool_frag *xg_find_litpool (struct litpool_seg *lps,
struct litpool_frag *lpf,
addressT addr)
{
struct litpool_frag *lp = lpf->prev;
gas_assert (lp->fragP);
while (lp->fragP->fr_subtype == RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
{
lp = lp->prev;
if (lp->fragP == NULL)
{
/* End of list; have to bite the bullet.
Take the nearest. */
lp = lpf->prev;
break;
}
/* Does it (conservatively) reach? */
if (addr - lp->addr <= 128 * 1024)
{
if (lp->fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN &&
lp->literal_count < MAX_POOL_LITERALS)
{
/* Found a good one. */
break;
}
else if (lp->prev->fragP &&
addr - lp->prev->addr > 128 * 1024 &&
lp->prev->literal_count < MAX_POOL_LITERALS)
{
/* This is still a "candidate" but the next one
will be too far away, so revert to the nearest
one, convert it and add the jump around. */
lp = lpf->prev;
break;
}
}
}
if (lp->literal_count >= MAX_POOL_LITERALS)
{
lp = lpf->prev;
while (lp && lp->fragP && lp->literal_count >= MAX_POOL_LITERALS)
{
lp = lp->prev;
}
gas_assert (lp);
}
gas_assert (lp && lp->fragP && lp->literal_count < MAX_POOL_LITERALS);
++lp->literal_count;
/* Convert candidate and add the jump around. */
if (lp->fragP->fr_subtype == RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
xg_promote_candidate_litpool (lps, lp);
return lp;
}
static void
xtensa_move_literals (void)
{
......@@ -11245,49 +11317,12 @@ xtensa_move_literals (void)
preferring non-"candidate" positions to avoid
the jump-around. */
fragS *litfrag = fragP->tc_frag_data.literal_frags[slot];
struct litpool_frag *lp = lpf->prev;
if (!lp->fragP)
{
break;
}
while (lp->fragP->fr_subtype ==
RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
{
lp = lp->prev;
if (lp->fragP == NULL)
{
/* End of list; have to bite the bullet.
Take the nearest. */
lp = lpf->prev;
break;
}
/* Does it (conservatively) reach? */
if (addr - lp->addr <= 128 * 1024)
{
if (lp->fragP->fr_subtype == RELAX_LITERAL_POOL_BEGIN)
{
/* Found a good one. */
break;
}
else if (lp->prev->fragP &&
addr - lp->prev->addr > 128 * 1024)
{
/* This is still a "candidate" but the next one
will be too far away, so revert to the nearest
one, convert it and add the jump around. */
lp = lpf->prev;
break;
}
}
}
/* Convert candidate and add the jump around. */
if (lp->fragP->fr_subtype ==
RELAX_LITERAL_POOL_CANDIDATE_BEGIN)
xg_promote_candidate_litpool (lps, lp);
if (! litfrag->tc_frag_data.literal_frag)
if (!litfrag->tc_frag_data.literal_frag)
{
struct litpool_frag *lp;
lp = xg_find_litpool (lps, lpf, addr);
/* Take earliest use of this literal to avoid
forward refs. */
litfrag->tc_frag_data.literal_frag = lp->fragP;
......
......@@ -102,6 +102,7 @@ if [istarget xtensa*-*-*] then {
run_list_test "trampoline-2"
run_dump_test "first_frag_align"
run_dump_test "auto-litpools"
run_dump_test "auto-litpools-2"
run_dump_test "auto-litpools-first1"
run_dump_test "auto-litpools-first2"
run_dump_test "loc"
......
#as: --auto-litpools
#objdump: -d
#name: auto litpool size limitation
.*: +file format .*xtensa.*
#...
.text
.global _start
_start:
j 1f
.rep 33000
movi a2, 0xf03df03d
.endr
1:
ret
......@@ -6,7 +6,7 @@
#...
.*8:.*l32r.a2, 4 .*
#...
.*3e43b:.*j.3e444 .*
.*3f029:.*j.3f030 .*
#...
.*40754:.*l32r.a2, 3e440 .*
.*40752:.*l32r.a2, 3f02c .*
#...
.text
.align 4
.literal .L0, 0x12345
.literal .L1, 0x12345
.literal .L1, 0x78f078f0
f:
l32r a2, .L0
......
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