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re PR debug/48866 (gcc hangs when -g is set)

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PR debug/48866
* df.h (enum debug_temp_where): New.
(dead_debug_init, dead_debug_finish) Declare.
(dead_debug_add, dead_debug_insert_temp): Declare.
(struct dead_debug_use, struct dead_debug): Moved from...
* df-problems.c: ... here.
(df_set_unused_notes_for_mw): Bind debug uses of unused regno
to a debug temp.
(df_create_unused_note): Likewise.
(df_set_dead_notes_for_mw): Move comment where it belongs.
(dead_debug_init): Export.
(dead_debug_reset_uses): New, factored out of...
(dead_debug_finish): ...this.  Export.
(dead_debug_reset): Remove.
(dead_debug_add): Export.
(dead_debug_insert_before): Rename to...
(dead_debug_insert_temp): ... this.  Add where argument.  Export.
Locate stored value for BEFORE_WITH_VALUE.  Avoid repeat inserts.
Return insertion count.
(df_note_bb_compute): Adjust.
* dce.c (word_dce_process_block): Adjust dead debug uses.
(dce_process_block): Likewise.

From-SVN: r186422
This commit is contained in:
Alexandre Oliva 2012-04-13 15:56:21 +00:00 committed by Alexandre Oliva
parent 6ae1d471b1
commit 1adbb3614d
4 changed files with 301 additions and 103 deletions
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25
gcc/ChangeLog
View File

@ -1,3 +1,28 @@
2012-04-13 Alexandre Oliva <aoliva@redhat.com>
PR debug/48866
* df.h (enum debug_temp_where): New.
(dead_debug_init, dead_debug_finish) Declare.
(dead_debug_add, dead_debug_insert_temp): Declare.
(struct dead_debug_use, struct dead_debug): Moved from...
* df-problems.c: ... here.
(df_set_unused_notes_for_mw): Bind debug uses of unused regno
to a debug temp.
(df_create_unused_note): Likewise.
(df_set_dead_notes_for_mw): Move comment where it belongs.
(dead_debug_init): Export.
(dead_debug_reset_uses): New, factored out of...
(dead_debug_finish): ...this. Export.
(dead_debug_reset): Remove.
(dead_debug_add): Export.
(dead_debug_insert_before): Rename to...
(dead_debug_insert_temp): ... this. Add where argument. Export.
Locate stored value for BEFORE_WITH_VALUE. Avoid repeat inserts.
Return insertion count.
(df_note_bb_compute): Adjust.
* dce.c (word_dce_process_block): Adjust dead debug uses.
(dce_process_block): Likewise.
2012-04-13 Alexandre Oliva <aoliva@redhat.com>
* df-problems.c (df_note_bb_compute): Do not take note of

58
gcc/dce.c
View File

@ -807,6 +807,7 @@ word_dce_process_block (basic_block bb, bool redo_out)
bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
rtx insn;
bool block_changed;
struct dead_debug debug;
if (redo_out)
{
@ -828,11 +829,24 @@ word_dce_process_block (basic_block bb, bool redo_out)
}
bitmap_copy (local_live, DF_WORD_LR_OUT (bb));
dead_debug_init (&debug, NULL);
FOR_BB_INSNS_REVERSE (bb, insn)
if (NONDEBUG_INSN_P (insn))
if (DEBUG_INSN_P (insn))
{
df_ref *use_rec;
for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
if (DF_REF_REGNO (*use_rec) >= FIRST_PSEUDO_REGISTER
&& (GET_MODE_SIZE (GET_MODE (DF_REF_REAL_REG (*use_rec)))
== 2 * UNITS_PER_WORD)
&& !bitmap_bit_p (local_live, 2 * DF_REF_REGNO (*use_rec))
&& !bitmap_bit_p (local_live, 2 * DF_REF_REGNO (*use_rec) + 1))
dead_debug_add (&debug, *use_rec, DF_REF_REGNO (*use_rec));
}
else if (INSN_P (insn))
{
bool any_changed;
/* No matter if the instruction is needed or not, we remove
any regno in the defs from the live set. */
any_changed = df_word_lr_simulate_defs (insn, local_live);
@ -844,6 +858,15 @@ word_dce_process_block (basic_block bb, bool redo_out)
if (marked_insn_p (insn))
df_word_lr_simulate_uses (insn, local_live);
if (debug.used && !bitmap_empty_p (debug.used))
{
df_ref *def_rec;
for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
dead_debug_insert_temp (&debug, DF_REF_REGNO (*def_rec), insn,
DEBUG_TEMP_BEFORE_WITH_VALUE);
}
if (dump_file)
{
fprintf (dump_file, "finished processing insn %d live out = ",
@ -856,6 +879,7 @@ word_dce_process_block (basic_block bb, bool redo_out)
if (block_changed)
bitmap_copy (DF_WORD_LR_IN (bb), local_live);
dead_debug_finish (&debug, NULL);
BITMAP_FREE (local_live);
return block_changed;
}
@ -873,6 +897,7 @@ dce_process_block (basic_block bb, bool redo_out, bitmap au)
rtx insn;
bool block_changed;
df_ref *def_rec;
struct dead_debug debug;
if (redo_out)
{
@ -896,22 +921,36 @@ dce_process_block (basic_block bb, bool redo_out, bitmap au)
bitmap_copy (local_live, DF_LR_OUT (bb));
df_simulate_initialize_backwards (bb, local_live);
dead_debug_init (&debug, NULL);
FOR_BB_INSNS_REVERSE (bb, insn)
if (INSN_P (insn))
if (DEBUG_INSN_P (insn))
{
df_ref *use_rec;
for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
if (!bitmap_bit_p (local_live, DF_REF_REGNO (*use_rec))
&& !bitmap_bit_p (au, DF_REF_REGNO (*use_rec)))
dead_debug_add (&debug, *use_rec, DF_REF_REGNO (*use_rec));
}
else if (INSN_P (insn))
{
bool needed = marked_insn_p (insn);
/* The insn is needed if there is someone who uses the output. */
if (!needed)
for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
|| bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
{
needed = true;
mark_insn (insn, true);
break;
}
{
dead_debug_insert_temp (&debug, DF_REF_REGNO (*def_rec), insn,
DEBUG_TEMP_BEFORE_WITH_VALUE);
if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
|| bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
{
needed = true;
mark_insn (insn, true);
break;
}
}
/* No matter if the instruction is needed or not, we remove
any regno in the defs from the live set. */
@ -923,6 +962,7 @@ dce_process_block (basic_block bb, bool redo_out, bitmap au)
df_simulate_uses (insn, local_live);
}
dead_debug_finish (&debug, NULL);
df_simulate_finalize_backwards (bb, local_live);
block_changed = !bitmap_equal_p (local_live, DF_LR_IN (bb));

279
gcc/df-problems.c
View File

@ -2886,25 +2886,6 @@ df_whole_mw_reg_unused_p (struct df_mw_hardreg *mws,
}
/* Node of a linked list of uses of dead REGs in debug insns. */
struct dead_debug_use
{
df_ref use;
struct dead_debug_use *next;
};
/* Linked list of the above, with a bitmap of the REGs in the
list. */
struct dead_debug
{
struct dead_debug_use *head;
bitmap used;
bitmap to_rescan;
};
static void dead_debug_reset (struct dead_debug *, unsigned int);
/* Set the REG_UNUSED notes for the multiword hardreg defs in INSN
based on the bits in LIVE. Do not generate notes for registers in
artificial uses. DO_NOT_GEN is updated so that REG_DEAD notes are
@ -2930,7 +2911,7 @@ df_set_unused_notes_for_mw (rtx insn, struct df_mw_hardreg *mws,
{
unsigned int regno = mws->start_regno;
df_set_note (REG_UNUSED, insn, mws->mw_reg);
dead_debug_reset (debug, regno);
dead_debug_insert_temp (debug, regno, insn, DEBUG_TEMP_AFTER_WITH_REG);
#ifdef REG_DEAD_DEBUGGING
df_print_note ("adding 1: ", insn, REG_NOTES (insn));
@ -2945,7 +2926,7 @@ df_set_unused_notes_for_mw (rtx insn, struct df_mw_hardreg *mws,
&& !bitmap_bit_p (artificial_uses, r))
{
df_set_note (REG_UNUSED, insn, regno_reg_rtx[r]);
dead_debug_reset (debug, r);
dead_debug_insert_temp (debug, r, insn, DEBUG_TEMP_AFTER_WITH_REG);
#ifdef REG_DEAD_DEBUGGING
df_print_note ("adding 2: ", insn, REG_NOTES (insn));
#endif
@ -3013,12 +2994,12 @@ df_set_dead_notes_for_mw (rtx insn, struct df_mw_hardreg *mws,
if (df_whole_mw_reg_dead_p (mws, live, artificial_uses, do_not_gen))
{
/* Add a dead note for the entire multi word register. */
if (is_debug)
{
*added_notes_p = true;
return;
}
/* Add a dead note for the entire multi word register. */
df_set_note (REG_DEAD, insn, mws->mw_reg);
#ifdef REG_DEAD_DEBUGGING
df_print_note ("adding 1: ", insn, REG_NOTES (insn));
@ -3072,7 +3053,7 @@ df_create_unused_note (rtx insn, df_ref def,
rtx reg = (DF_REF_LOC (def))
? *DF_REF_REAL_LOC (def): DF_REF_REG (def);
df_set_note (REG_UNUSED, insn, reg);
dead_debug_reset (debug, dregno);
dead_debug_insert_temp (debug, dregno, insn, DEBUG_TEMP_AFTER_WITH_REG);
#ifdef REG_DEAD_DEBUGGING
df_print_note ("adding 3: ", insn, REG_NOTES (insn));
#endif
@ -3083,7 +3064,7 @@ df_create_unused_note (rtx insn, df_ref def,
/* Initialize DEBUG to an empty list, and clear USED, if given. */
static inline void
void
dead_debug_init (struct dead_debug *debug, bitmap used)
{
debug->head = NULL;
@ -3093,32 +3074,83 @@ dead_debug_init (struct dead_debug *debug, bitmap used)
bitmap_clear (used);
}
/* Reset all debug insns with pending uses. Release the bitmap in it,
unless it is USED. USED must be the same bitmap passed to
dead_debug_init. */
static inline void
dead_debug_finish (struct dead_debug *debug, bitmap used)
/* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
each reset insn. DEBUG is not otherwise modified. If HEAD is
DEBUG->head, DEBUG->head will be set to NULL at the end.
Otherwise, entries from DEBUG->head that pertain to reset insns
will be removed, and only then rescanned. */
static void
dead_debug_reset_uses (struct dead_debug *debug, struct dead_debug_use *head)
{
struct dead_debug_use *head;
rtx insn = NULL;
bool got_head = (debug->head == head);
bitmap rescan;
struct dead_debug_use **tailp = &debug->head;
struct dead_debug_use *cur;
bitmap_iterator bi;
unsigned int uid;
if (debug->used != used)
BITMAP_FREE (debug->used);
if (got_head)
rescan = NULL;
else
rescan = BITMAP_ALLOC (NULL);
while ((head = debug->head))
while (head)
{
struct dead_debug_use *next = head->next;
rtx insn;
insn = DF_REF_INSN (head->use);
if (!head->next || DF_REF_INSN (head->next->use) != insn)
if (!next || DF_REF_INSN (next->use) != insn)
{
INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
df_insn_rescan_debug_internal (insn);
if (got_head)
df_insn_rescan_debug_internal (insn);
else
bitmap_set_bit (rescan, INSN_UID (insn));
if (debug->to_rescan)
bitmap_clear_bit (debug->to_rescan, INSN_UID (insn));
}
debug->head = head->next;
XDELETE (head);
head = next;
}
if (got_head)
{
debug->head = NULL;
return;
}
while ((cur = *tailp))
if (bitmap_bit_p (rescan, INSN_UID (DF_REF_INSN (cur->use))))
{
*tailp = cur->next;
XDELETE (cur);
}
else
tailp = &cur->next;
EXECUTE_IF_SET_IN_BITMAP (rescan, 0, uid, bi)
{
struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
if (insn_info)
df_insn_rescan_debug_internal (insn_info->insn);
}
BITMAP_FREE (rescan);
}
/* Reset all debug insns with pending uses. Release the bitmap in it,
unless it is USED. USED must be the same bitmap passed to
dead_debug_init. */
void
dead_debug_finish (struct dead_debug *debug, bitmap used)
{
if (debug->used != used)
BITMAP_FREE (debug->used);
dead_debug_reset_uses (debug, debug->head);
if (debug->to_rescan)
{
bitmap_iterator bi;
@ -3134,54 +3166,9 @@ dead_debug_finish (struct dead_debug *debug, bitmap used)
}
}
/* Reset DEBUG_INSNs with pending uses of DREGNO. */
static void
dead_debug_reset (struct dead_debug *debug, unsigned int dregno)
{
struct dead_debug_use **tailp = &debug->head;
struct dead_debug_use **insnp = &debug->head;
struct dead_debug_use *cur;
rtx insn;
if (!debug->used || !bitmap_clear_bit (debug->used, dregno))
return;
while ((cur = *tailp))
{
if (DF_REF_REGNO (cur->use) == dregno)
{
*tailp = cur->next;
insn = DF_REF_INSN (cur->use);
INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
if (debug->to_rescan == NULL)
debug->to_rescan = BITMAP_ALLOC (NULL);
bitmap_set_bit (debug->to_rescan, INSN_UID (insn));
XDELETE (cur);
/* If the current use isn't the first one attached to INSN, go back
to this first use. We assume that the uses attached to an insn
are adjacent. */
if (tailp != insnp && DF_REF_INSN ((*insnp)->use) == insn)
tailp = insnp;
/* Then remove all the other uses attached to INSN. */
while ((cur = *tailp) && DF_REF_INSN (cur->use) == insn)
{
*tailp = cur->next;
XDELETE (cur);
}
insnp = tailp;
}
else
{
if (DF_REF_INSN ((*insnp)->use) != DF_REF_INSN (cur->use))
insnp = tailp;
tailp = &(*tailp)->next;
}
}
}
/* Add USE to DEBUG. It must be a dead reference to UREGNO in a debug
insn. Create a bitmap for DEBUG as needed. */
static inline void
void
dead_debug_add (struct dead_debug *debug, df_ref use, unsigned int uregno)
{
struct dead_debug_use *newddu = XNEW (struct dead_debug_use);
@ -3197,23 +3184,27 @@ dead_debug_add (struct dead_debug *debug, df_ref use, unsigned int uregno)
}
/* If UREGNO is referenced by any entry in DEBUG, emit a debug insn
before INSN that binds the REG to a debug temp, and replace all
uses of UREGNO in DEBUG with uses of the debug temp. INSN must be
the insn where UREGNO dies. */
static inline void
dead_debug_insert_before (struct dead_debug *debug, unsigned int uregno,
rtx insn)
before or after INSN (depending on WHERE), that binds a debug temp
to the widest-mode use of UREGNO, if WHERE is *_WITH_REG, or the
value stored in UREGNO by INSN otherwise, and replace all uses of
UREGNO in DEBUG with uses of the debug temp. INSN must be where
UREGNO dies, if WHERE is *_BEFORE_*, or where it is set otherwise.
Return the number of debug insns emitted. */
int
dead_debug_insert_temp (struct dead_debug *debug, unsigned int uregno,
rtx insn, enum debug_temp_where where)
{
struct dead_debug_use **tailp = &debug->head;
struct dead_debug_use *cur;
struct dead_debug_use *uses = NULL;
struct dead_debug_use **usesp = &uses;
rtx reg = NULL;
rtx breg;
rtx dval;
rtx bind;
if (!debug->used || !bitmap_clear_bit (debug->used, uregno))
return;
return 0;
/* Move all uses of uregno from debug->head to uses, setting mode to
the widest referenced mode. */
@ -3237,17 +3228,114 @@ dead_debug_insert_before (struct dead_debug *debug, unsigned int uregno,
/* We may have dangling bits in debug->used for registers that were part
of a multi-register use, one component of which has been reset. */
if (reg == NULL)
return;
{
gcc_checking_assert (!uses);
return 0;
}
gcc_checking_assert (uses);
breg = reg;
/* Recover the expression INSN stores in REG. */
if (where == DEBUG_TEMP_BEFORE_WITH_VALUE)
{
rtx set = single_set (insn);
rtx dest, src;
if (set)
{
dest = SET_DEST (set);
src = SET_SRC (set);
/* Lose if the REG-setting insn is a CALL. */
if (GET_CODE (src) == CALL)
{
while (uses)
{
cur = uses->next;
XDELETE (uses);
uses = cur;
}
return 0;
}
}
/* ??? Should we try to extract it from a PARALLEL? */
if (!set)
breg = NULL;
/* Cool, it's the same REG, we can use SRC. */
else if (dest == reg)
breg = copy_rtx (src);
else if (REG_P (dest))
{
/* Hmm... Something's fishy, we should be setting REG here. */
if (REGNO (dest) != REGNO (reg))
breg = NULL;
/* Ok, it's the same (hardware) REG, but with a different
mode, so SUBREG it. */
else
breg = lowpart_subreg (GET_MODE (reg), copy_rtx (src),
GET_MODE (dest));
}
else if (GET_CODE (dest) == SUBREG)
{
/* We should be setting REG here. Lose. */
if (REGNO (SUBREG_REG (dest)) != REGNO (reg))
breg = NULL;
/* Lose if we're setting something other than the lowpart of
REG. */
else if (!subreg_lowpart_p (dest))
breg = NULL;
/* If we're not overwriting all the hardware registers that
setting REG in its mode would, we won't know what to bind
the debug temp to. */
else if (REGNO (reg) < FIRST_PSEUDO_REGISTER
&& (hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]
!= hard_regno_nregs[REGNO (reg)][GET_MODE (dest)]))
breg = NULL;
/* Yay, we can use SRC, just adjust its mode. */
else
breg = lowpart_subreg (GET_MODE (reg), copy_rtx (src),
GET_MODE (dest));
}
/* Oh well, we're out of luck. */
else
breg = NULL;
/* We couldn't figure out the value stored in REG, so reset all
of its pending debug uses. */
if (!breg)
{
dead_debug_reset_uses (debug, uses);
return 0;
}
}
/* If there's a single (debug) use of an otherwise unused REG, and
the debug use is not part of a larger expression, then it
probably doesn't make sense to introduce a new debug temp. */
if (where == DEBUG_TEMP_AFTER_WITH_REG && !uses->next)
{
rtx next = DF_REF_INSN (uses->use);
if (DEBUG_INSN_P (next) && reg == INSN_VAR_LOCATION_LOC (next))
{
XDELETE (uses);
return 0;
}
}
/* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
dval = make_debug_expr_from_rtl (reg);
/* Emit a debug bind insn before the insn in which reg dies. */
bind = gen_rtx_VAR_LOCATION (GET_MODE (reg),
DEBUG_EXPR_TREE_DECL (dval), reg,
DEBUG_EXPR_TREE_DECL (dval), breg,
VAR_INIT_STATUS_INITIALIZED);
bind = emit_debug_insn_before (bind, insn);
if (where == DEBUG_TEMP_AFTER_WITH_REG)
bind = emit_debug_insn_after (bind, insn);
else
bind = emit_debug_insn_before (bind, insn);
df_insn_rescan (bind);
/* Adjust all uses. */
@ -3265,6 +3353,8 @@ dead_debug_insert_before (struct dead_debug *debug, unsigned int uregno,
uses = cur->next;
XDELETE (cur);
}
return 1;
}
/* Recompute the REG_DEAD and REG_UNUSED notes and compute register
@ -3464,7 +3554,8 @@ df_note_bb_compute (unsigned int bb_index,
break;
}
else
dead_debug_insert_before (&debug, uregno, insn);
dead_debug_insert_temp (&debug, uregno, insn,
DEBUG_TEMP_BEFORE_WITH_REG);
if ( (!(DF_REF_FLAGS (use)
& (DF_REF_MW_HARDREG | DF_REF_READ_WRITE)))

42
gcc/df.h
View File

@ -1101,4 +1101,46 @@ extern void union_defs (df_ref, struct web_entry *,
unsigned int *used, struct web_entry *,
bool (*fun) (struct web_entry *, struct web_entry *));
/* Debug uses of dead regs. */
/* Node of a linked list of uses of dead REGs in debug insns. */
struct dead_debug_use
{
df_ref use;
struct dead_debug_use *next;
};
/* Linked list of the above, with a bitmap of the REGs in the
list. */
struct dead_debug
{
struct dead_debug_use *head;
bitmap used;
bitmap to_rescan;
};
/* This type controls the behavior of dead_debug_insert_temp WRT
UREGNO and INSN. */
enum debug_temp_where
{
/* Bind a newly-created debug temporary to a REG for UREGNO, and
insert the debug insn before INSN. REG is expected to die at
INSN. */
DEBUG_TEMP_BEFORE_WITH_REG = -1,
/* Bind a newly-created debug temporary to the value INSN stores
in REG, and insert the debug insn before INSN. */
DEBUG_TEMP_BEFORE_WITH_VALUE = 0,
/* Bind a newly-created debug temporary to a REG for UREGNO, and
insert the debug insn after INSN. REG is expected to be set at
INSN. */
DEBUG_TEMP_AFTER_WITH_REG = 1
};
extern void dead_debug_init (struct dead_debug *, bitmap);
extern void dead_debug_finish (struct dead_debug *, bitmap);
extern void dead_debug_add (struct dead_debug *, df_ref, unsigned int);
extern int dead_debug_insert_temp (struct dead_debug *,
unsigned int uregno, rtx insn,
enum debug_temp_where);
#endif /* GCC_DF_H */