1 /* Infrastructure for tracking user variable locations and values
2 throughout compilation.
3 Copyright (C) 2010, 2011, 2012 Free Software Foundation, Inc.
4 Contributed by Alexandre Oliva <aoliva@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
32 /* Replace auto-increment addressing modes with explicit operations to access
33 the same addresses without modifying the corresponding registers. */
36 cleanup_auto_inc_dec (rtx src
, enum machine_mode mem_mode ATTRIBUTE_UNUSED
)
40 const RTX_CODE code
= GET_CODE (x
);
56 /* SCRATCH must be shared because they represent distinct values. */
59 if (REG_P (XEXP (x
, 0)) && REGNO (XEXP (x
, 0)) < FIRST_PSEUDO_REGISTER
)
64 if (shared_const_p (x
))
69 mem_mode
= GET_MODE (x
);
74 gcc_assert (mem_mode
!= VOIDmode
&& mem_mode
!= BLKmode
);
75 return gen_rtx_PLUS (GET_MODE (x
),
76 cleanup_auto_inc_dec (XEXP (x
, 0), mem_mode
),
77 GEN_INT (code
== PRE_INC
78 ? GET_MODE_SIZE (mem_mode
)
79 : -GET_MODE_SIZE (mem_mode
)));
85 return cleanup_auto_inc_dec (code
== PRE_MODIFY
86 ? XEXP (x
, 1) : XEXP (x
, 0),
93 /* Copy the various flags, fields, and other information. We assume
94 that all fields need copying, and then clear the fields that should
95 not be copied. That is the sensible default behavior, and forces
96 us to explicitly document why we are *not* copying a flag. */
97 x
= shallow_copy_rtx (x
);
99 /* We do not copy the USED flag, which is used as a mark bit during
100 walks over the RTL. */
101 RTX_FLAG (x
, used
) = 0;
103 /* We do not copy FRAME_RELATED for INSNs. */
105 RTX_FLAG (x
, frame_related
) = 0;
107 fmt
= GET_RTX_FORMAT (code
);
108 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
110 XEXP (x
, i
) = cleanup_auto_inc_dec (XEXP (x
, i
), mem_mode
);
111 else if (fmt
[i
] == 'E' || fmt
[i
] == 'V')
114 XVEC (x
, i
) = rtvec_alloc (XVECLEN (x
, i
));
115 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
117 = cleanup_auto_inc_dec (XVECEXP (src
, i
, j
), mem_mode
);
120 #else /* !AUTO_INC_DEC */
122 #endif /* !AUTO_INC_DEC */
127 /* Auxiliary data structure for propagate_for_debug_stmt. */
129 struct rtx_subst_pair
135 /* DATA points to an rtx_subst_pair. Return the value that should be
139 propagate_for_debug_subst (rtx from
, const_rtx old_rtx
, void *data
)
141 struct rtx_subst_pair
*pair
= (struct rtx_subst_pair
*)data
;
143 if (!rtx_equal_p (from
, old_rtx
))
147 pair
->adjusted
= true;
148 pair
->to
= cleanup_auto_inc_dec (pair
->to
, VOIDmode
);
149 pair
->to
= make_compound_operation (pair
->to
, SET
);
152 return copy_rtx (pair
->to
);
155 /* Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN
156 and LAST, not including INSN, but including LAST. Also stop at the end
157 of THIS_BASIC_BLOCK. */
160 propagate_for_debug (rtx insn
, rtx last
, rtx dest
, rtx src
,
161 basic_block this_basic_block
)
163 rtx next
, loc
, end
= NEXT_INSN (BB_END (this_basic_block
));
165 struct rtx_subst_pair p
;
169 next
= NEXT_INSN (insn
);
170 last
= NEXT_INSN (last
);
171 while (next
!= last
&& next
!= end
)
174 next
= NEXT_INSN (insn
);
175 if (DEBUG_INSN_P (insn
))
177 loc
= simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn
),
178 dest
, propagate_for_debug_subst
, &p
);
179 if (loc
== INSN_VAR_LOCATION_LOC (insn
))
181 INSN_VAR_LOCATION_LOC (insn
) = loc
;
182 df_insn_rescan (insn
);
187 /* Initialize DEBUG to an empty list, and clear USED, if given. */
189 dead_debug_init (struct dead_debug
*debug
, bitmap used
)
193 debug
->to_rescan
= NULL
;
198 /* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
199 each reset insn. DEBUG is not otherwise modified. If HEAD is
200 DEBUG->head, DEBUG->head will be set to NULL at the end.
201 Otherwise, entries from DEBUG->head that pertain to reset insns
202 will be removed, and only then rescanned. */
205 dead_debug_reset_uses (struct dead_debug
*debug
, struct dead_debug_use
*head
)
207 bool got_head
= (debug
->head
== head
);
209 struct dead_debug_use
**tailp
= &debug
->head
;
210 struct dead_debug_use
*cur
;
217 rescan
= BITMAP_ALLOC (NULL
);
221 struct dead_debug_use
*next
= head
->next
;
224 insn
= DF_REF_INSN (head
->use
);
225 if (!next
|| DF_REF_INSN (next
->use
) != insn
)
227 INSN_VAR_LOCATION_LOC (insn
) = gen_rtx_UNKNOWN_VAR_LOC ();
229 df_insn_rescan_debug_internal (insn
);
231 bitmap_set_bit (rescan
, INSN_UID (insn
));
232 if (debug
->to_rescan
)
233 bitmap_clear_bit (debug
->to_rescan
, INSN_UID (insn
));
245 while ((cur
= *tailp
))
246 if (bitmap_bit_p (rescan
, INSN_UID (DF_REF_INSN (cur
->use
))))
254 EXECUTE_IF_SET_IN_BITMAP (rescan
, 0, uid
, bi
)
256 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
258 df_insn_rescan_debug_internal (insn_info
->insn
);
261 BITMAP_FREE (rescan
);
264 /* Reset all debug insns with pending uses. Release the bitmap in it,
265 unless it is USED. USED must be the same bitmap passed to
268 dead_debug_finish (struct dead_debug
*debug
, bitmap used
)
270 if (debug
->used
!= used
)
271 BITMAP_FREE (debug
->used
);
273 dead_debug_reset_uses (debug
, debug
->head
);
275 if (debug
->to_rescan
)
280 EXECUTE_IF_SET_IN_BITMAP (debug
->to_rescan
, 0, uid
, bi
)
282 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
284 df_insn_rescan (insn_info
->insn
);
286 BITMAP_FREE (debug
->to_rescan
);
290 /* Add USE to DEBUG. It must be a dead reference to UREGNO in a debug
291 insn. Create a bitmap for DEBUG as needed. */
293 dead_debug_add (struct dead_debug
*debug
, df_ref use
, unsigned int uregno
)
295 struct dead_debug_use
*newddu
= XNEW (struct dead_debug_use
);
298 newddu
->next
= debug
->head
;
299 debug
->head
= newddu
;
302 debug
->used
= BITMAP_ALLOC (NULL
);
304 /* ??? If we dealt with split multi-registers below, we should set
305 all registers for the used mode in case of hardware
307 bitmap_set_bit (debug
->used
, uregno
);
310 /* If UREGNO is referenced by any entry in DEBUG, emit a debug insn
311 before or after INSN (depending on WHERE), that binds a debug temp
312 to the widest-mode use of UREGNO, if WHERE is *_WITH_REG, or the
313 value stored in UREGNO by INSN otherwise, and replace all uses of
314 UREGNO in DEBUG with uses of the debug temp. INSN must be where
315 UREGNO dies, if WHERE is *_BEFORE_*, or where it is set otherwise.
316 Return the number of debug insns emitted. */
318 dead_debug_insert_temp (struct dead_debug
*debug
, unsigned int uregno
,
319 rtx insn
, enum debug_temp_where where
)
321 struct dead_debug_use
**tailp
= &debug
->head
;
322 struct dead_debug_use
*cur
;
323 struct dead_debug_use
*uses
= NULL
;
324 struct dead_debug_use
**usesp
= &uses
;
330 if (!debug
->used
|| !bitmap_clear_bit (debug
->used
, uregno
))
333 /* Move all uses of uregno from debug->head to uses, setting mode to
334 the widest referenced mode. */
335 while ((cur
= *tailp
))
337 if (DF_REF_REGNO (cur
->use
) == uregno
)
344 || (GET_MODE_BITSIZE (GET_MODE (reg
))
345 < GET_MODE_BITSIZE (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)))))
346 reg
= *DF_REF_REAL_LOC (cur
->use
);
349 tailp
= &(*tailp
)->next
;
352 /* We may have dangling bits in debug->used for registers that were part
353 of a multi-register use, one component of which has been reset. */
356 gcc_checking_assert (!uses
);
360 gcc_checking_assert (uses
);
363 /* Recover the expression INSN stores in REG. */
364 if (where
== DEBUG_TEMP_BEFORE_WITH_VALUE
)
366 rtx set
= single_set (insn
);
371 dest
= SET_DEST (set
);
373 /* Lose if the REG-setting insn is a CALL. */
374 if (GET_CODE (src
) == CALL
)
386 /* ??? Should we try to extract it from a PARALLEL? */
389 /* Cool, it's the same REG, we can use SRC. */
390 else if (dest
== reg
)
391 breg
= copy_rtx (src
);
392 else if (REG_P (dest
))
394 /* Hmm... Something's fishy, we should be setting REG here. */
395 if (REGNO (dest
) != REGNO (reg
))
397 /* If we're not overwriting all the hardware registers that
398 setting REG in its mode would, we won't know what to bind
399 the debug temp to. ??? We could bind the debug_expr to a
400 CONCAT or PARALLEL with the split multi-registers, and
401 replace them as we found the corresponding sets. */
402 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
403 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
404 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
406 /* Ok, it's the same (hardware) REG, but with a different
407 mode, so SUBREG it. */
409 breg
= lowpart_subreg (GET_MODE (reg
), copy_rtx (src
),
412 else if (GET_CODE (dest
) == SUBREG
)
414 /* We should be setting REG here. Lose. */
415 if (REGNO (SUBREG_REG (dest
)) != REGNO (reg
))
417 /* Lose if we're setting something other than the lowpart of
419 else if (!subreg_lowpart_p (dest
))
421 /* If we're not overwriting all the hardware registers that
422 setting REG in its mode would, we won't know what to bind
423 the debug temp to. */
424 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
425 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
426 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
428 /* Yay, we can use SRC, just adjust its mode. */
430 breg
= lowpart_subreg (GET_MODE (reg
), copy_rtx (src
),
433 /* Oh well, we're out of luck. */
437 /* We couldn't figure out the value stored in REG, so reset all
438 of its pending debug uses. */
441 dead_debug_reset_uses (debug
, uses
);
446 /* If there's a single (debug) use of an otherwise unused REG, and
447 the debug use is not part of a larger expression, then it
448 probably doesn't make sense to introduce a new debug temp. */
449 if (where
== DEBUG_TEMP_AFTER_WITH_REG
&& !uses
->next
)
451 rtx next
= DF_REF_INSN (uses
->use
);
453 if (DEBUG_INSN_P (next
) && reg
== INSN_VAR_LOCATION_LOC (next
))
460 /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
461 dval
= make_debug_expr_from_rtl (reg
);
463 /* Emit a debug bind insn before the insn in which reg dies. */
464 bind
= gen_rtx_VAR_LOCATION (GET_MODE (reg
),
465 DEBUG_EXPR_TREE_DECL (dval
), breg
,
466 VAR_INIT_STATUS_INITIALIZED
);
468 if (where
== DEBUG_TEMP_AFTER_WITH_REG
)
469 bind
= emit_debug_insn_after (bind
, insn
);
471 bind
= emit_debug_insn_before (bind
, insn
);
472 df_insn_rescan (bind
);
474 /* Adjust all uses. */
477 if (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)) == GET_MODE (reg
))
478 *DF_REF_REAL_LOC (cur
->use
) = dval
;
480 *DF_REF_REAL_LOC (cur
->use
)
481 = gen_lowpart_SUBREG (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)), dval
);
482 /* ??? Should we simplify subreg of subreg? */
483 if (debug
->to_rescan
== NULL
)
484 debug
->to_rescan
= BITMAP_ALLOC (NULL
);
485 bitmap_set_bit (debug
->to_rescan
, INSN_UID (DF_REF_INSN (cur
->use
)));