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
);
53 /* SCRATCH must be shared because they represent distinct values. */
56 if (REG_P (XEXP (x
, 0)) && REGNO (XEXP (x
, 0)) < FIRST_PSEUDO_REGISTER
)
61 if (shared_const_p (x
))
66 mem_mode
= GET_MODE (x
);
71 gcc_assert (mem_mode
!= VOIDmode
&& mem_mode
!= BLKmode
);
72 return gen_rtx_PLUS (GET_MODE (x
),
73 cleanup_auto_inc_dec (XEXP (x
, 0), mem_mode
),
74 GEN_INT (code
== PRE_INC
75 ? GET_MODE_SIZE (mem_mode
)
76 : -GET_MODE_SIZE (mem_mode
)));
82 return cleanup_auto_inc_dec (code
== PRE_MODIFY
83 ? XEXP (x
, 1) : XEXP (x
, 0),
90 /* Copy the various flags, fields, and other information. We assume
91 that all fields need copying, and then clear the fields that should
92 not be copied. That is the sensible default behavior, and forces
93 us to explicitly document why we are *not* copying a flag. */
94 x
= shallow_copy_rtx (x
);
96 /* We do not copy the USED flag, which is used as a mark bit during
97 walks over the RTL. */
98 RTX_FLAG (x
, used
) = 0;
100 /* We do not copy FRAME_RELATED for INSNs. */
102 RTX_FLAG (x
, frame_related
) = 0;
104 fmt
= GET_RTX_FORMAT (code
);
105 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
107 XEXP (x
, i
) = cleanup_auto_inc_dec (XEXP (x
, i
), mem_mode
);
108 else if (fmt
[i
] == 'E' || fmt
[i
] == 'V')
111 XVEC (x
, i
) = rtvec_alloc (XVECLEN (x
, i
));
112 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
114 = cleanup_auto_inc_dec (XVECEXP (src
, i
, j
), mem_mode
);
117 #else /* !AUTO_INC_DEC */
119 #endif /* !AUTO_INC_DEC */
124 /* Auxiliary data structure for propagate_for_debug_stmt. */
126 struct rtx_subst_pair
132 /* DATA points to an rtx_subst_pair. Return the value that should be
136 propagate_for_debug_subst (rtx from
, const_rtx old_rtx
, void *data
)
138 struct rtx_subst_pair
*pair
= (struct rtx_subst_pair
*)data
;
140 if (!rtx_equal_p (from
, old_rtx
))
144 pair
->adjusted
= true;
145 pair
->to
= cleanup_auto_inc_dec (pair
->to
, VOIDmode
);
146 pair
->to
= make_compound_operation (pair
->to
, SET
);
149 return copy_rtx (pair
->to
);
152 /* Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN
153 and LAST, not including INSN, but including LAST. Also stop at the end
154 of THIS_BASIC_BLOCK. */
157 propagate_for_debug (rtx insn
, rtx last
, rtx dest
, rtx src
,
158 basic_block this_basic_block
)
160 rtx next
, loc
, end
= NEXT_INSN (BB_END (this_basic_block
));
162 struct rtx_subst_pair p
;
166 next
= NEXT_INSN (insn
);
167 last
= NEXT_INSN (last
);
168 while (next
!= last
&& next
!= end
)
171 next
= NEXT_INSN (insn
);
172 if (DEBUG_INSN_P (insn
))
174 loc
= simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn
),
175 dest
, propagate_for_debug_subst
, &p
);
176 if (loc
== INSN_VAR_LOCATION_LOC (insn
))
178 INSN_VAR_LOCATION_LOC (insn
) = loc
;
179 df_insn_rescan (insn
);
184 /* Initialize DEBUG to an empty list, and clear USED, if given. */
186 dead_debug_init (struct dead_debug
*debug
, bitmap used
)
190 debug
->to_rescan
= NULL
;
195 /* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
196 each reset insn. DEBUG is not otherwise modified. If HEAD is
197 DEBUG->head, DEBUG->head will be set to NULL at the end.
198 Otherwise, entries from DEBUG->head that pertain to reset insns
199 will be removed, and only then rescanned. */
202 dead_debug_reset_uses (struct dead_debug
*debug
, struct dead_debug_use
*head
)
204 bool got_head
= (debug
->head
== head
);
206 struct dead_debug_use
**tailp
= &debug
->head
;
207 struct dead_debug_use
*cur
;
214 rescan
= BITMAP_ALLOC (NULL
);
218 struct dead_debug_use
*next
= head
->next
;
221 insn
= DF_REF_INSN (head
->use
);
222 if (!next
|| DF_REF_INSN (next
->use
) != insn
)
224 INSN_VAR_LOCATION_LOC (insn
) = gen_rtx_UNKNOWN_VAR_LOC ();
226 df_insn_rescan_debug_internal (insn
);
228 bitmap_set_bit (rescan
, INSN_UID (insn
));
229 if (debug
->to_rescan
)
230 bitmap_clear_bit (debug
->to_rescan
, INSN_UID (insn
));
242 while ((cur
= *tailp
))
243 if (bitmap_bit_p (rescan
, INSN_UID (DF_REF_INSN (cur
->use
))))
251 EXECUTE_IF_SET_IN_BITMAP (rescan
, 0, uid
, bi
)
253 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
255 df_insn_rescan_debug_internal (insn_info
->insn
);
258 BITMAP_FREE (rescan
);
261 /* Reset all debug insns with pending uses. Release the bitmap in it,
262 unless it is USED. USED must be the same bitmap passed to
265 dead_debug_finish (struct dead_debug
*debug
, bitmap used
)
267 if (debug
->used
!= used
)
268 BITMAP_FREE (debug
->used
);
270 dead_debug_reset_uses (debug
, debug
->head
);
272 if (debug
->to_rescan
)
277 EXECUTE_IF_SET_IN_BITMAP (debug
->to_rescan
, 0, uid
, bi
)
279 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
281 df_insn_rescan (insn_info
->insn
);
283 BITMAP_FREE (debug
->to_rescan
);
287 /* Add USE to DEBUG. It must be a dead reference to UREGNO in a debug
288 insn. Create a bitmap for DEBUG as needed. */
290 dead_debug_add (struct dead_debug
*debug
, df_ref use
, unsigned int uregno
)
292 struct dead_debug_use
*newddu
= XNEW (struct dead_debug_use
);
295 newddu
->next
= debug
->head
;
296 debug
->head
= newddu
;
299 debug
->used
= BITMAP_ALLOC (NULL
);
301 /* ??? If we dealt with split multi-registers below, we should set
302 all registers for the used mode in case of hardware
304 bitmap_set_bit (debug
->used
, uregno
);
307 /* If UREGNO is referenced by any entry in DEBUG, emit a debug insn
308 before or after INSN (depending on WHERE), that binds a debug temp
309 to the widest-mode use of UREGNO, if WHERE is *_WITH_REG, or the
310 value stored in UREGNO by INSN otherwise, and replace all uses of
311 UREGNO in DEBUG with uses of the debug temp. INSN must be where
312 UREGNO dies, if WHERE is *_BEFORE_*, or where it is set otherwise.
313 Return the number of debug insns emitted. */
315 dead_debug_insert_temp (struct dead_debug
*debug
, unsigned int uregno
,
316 rtx insn
, enum debug_temp_where where
)
318 struct dead_debug_use
**tailp
= &debug
->head
;
319 struct dead_debug_use
*cur
;
320 struct dead_debug_use
*uses
= NULL
;
321 struct dead_debug_use
**usesp
= &uses
;
327 if (!debug
->used
|| !bitmap_clear_bit (debug
->used
, uregno
))
330 /* Move all uses of uregno from debug->head to uses, setting mode to
331 the widest referenced mode. */
332 while ((cur
= *tailp
))
334 if (DF_REF_REGNO (cur
->use
) == uregno
)
336 /* If this loc has been changed e.g. to debug_expr already
337 as part of a multi-register use, just drop it. */
338 if (!REG_P (*DF_REF_REAL_LOC (cur
->use
)))
349 || (GET_MODE_BITSIZE (GET_MODE (reg
))
350 < GET_MODE_BITSIZE (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)))))
351 reg
= *DF_REF_REAL_LOC (cur
->use
);
354 tailp
= &(*tailp
)->next
;
357 /* We may have dangling bits in debug->used for registers that were part
358 of a multi-register use, one component of which has been reset. */
361 gcc_checking_assert (!uses
);
365 gcc_checking_assert (uses
);
368 /* Recover the expression INSN stores in REG. */
369 if (where
== DEBUG_TEMP_BEFORE_WITH_VALUE
)
371 rtx set
= single_set (insn
);
376 dest
= SET_DEST (set
);
378 /* Lose if the REG-setting insn is a CALL. */
379 if (GET_CODE (src
) == CALL
)
391 /* ??? Should we try to extract it from a PARALLEL? */
394 /* Cool, it's the same REG, we can use SRC. */
395 else if (dest
== reg
)
396 breg
= cleanup_auto_inc_dec (src
, VOIDmode
);
397 else if (REG_P (dest
))
399 /* Hmm... Something's fishy, we should be setting REG here. */
400 if (REGNO (dest
) != REGNO (reg
))
402 /* If we're not overwriting all the hardware registers that
403 setting REG in its mode would, we won't know what to bind
404 the debug temp to. ??? We could bind the debug_expr to a
405 CONCAT or PARALLEL with the split multi-registers, and
406 replace them as we found the corresponding sets. */
407 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
408 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
409 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
411 /* Ok, it's the same (hardware) REG, but with a different
412 mode, so SUBREG it. */
414 breg
= lowpart_subreg (GET_MODE (reg
),
415 cleanup_auto_inc_dec (src
, VOIDmode
),
418 else if (GET_CODE (dest
) == SUBREG
)
420 /* We should be setting REG here. Lose. */
421 if (REGNO (SUBREG_REG (dest
)) != REGNO (reg
))
423 /* Lose if we're setting something other than the lowpart of
425 else if (!subreg_lowpart_p (dest
))
427 /* If we're not overwriting all the hardware registers that
428 setting REG in its mode would, we won't know what to bind
429 the debug temp to. */
430 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
431 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
432 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
434 /* Yay, we can use SRC, just adjust its mode. */
436 breg
= lowpart_subreg (GET_MODE (reg
),
437 cleanup_auto_inc_dec (src
, VOIDmode
),
440 /* Oh well, we're out of luck. */
444 /* We couldn't figure out the value stored in REG, so reset all
445 of its pending debug uses. */
448 dead_debug_reset_uses (debug
, uses
);
453 /* If there's a single (debug) use of an otherwise unused REG, and
454 the debug use is not part of a larger expression, then it
455 probably doesn't make sense to introduce a new debug temp. */
456 if (where
== DEBUG_TEMP_AFTER_WITH_REG
&& !uses
->next
)
458 rtx next
= DF_REF_INSN (uses
->use
);
460 if (DEBUG_INSN_P (next
) && reg
== INSN_VAR_LOCATION_LOC (next
))
467 /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
468 dval
= make_debug_expr_from_rtl (reg
);
470 /* Emit a debug bind insn before the insn in which reg dies. */
471 bind
= gen_rtx_VAR_LOCATION (GET_MODE (reg
),
472 DEBUG_EXPR_TREE_DECL (dval
), breg
,
473 VAR_INIT_STATUS_INITIALIZED
);
475 if (where
== DEBUG_TEMP_AFTER_WITH_REG
)
476 bind
= emit_debug_insn_after (bind
, insn
);
478 bind
= emit_debug_insn_before (bind
, insn
);
479 df_insn_rescan (bind
);
481 /* Adjust all uses. */
484 if (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)) == GET_MODE (reg
))
485 *DF_REF_REAL_LOC (cur
->use
) = dval
;
487 *DF_REF_REAL_LOC (cur
->use
)
488 = gen_lowpart_SUBREG (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)), dval
);
489 /* ??? Should we simplify subreg of subreg? */
490 if (debug
->to_rescan
== NULL
)
491 debug
->to_rescan
= BITMAP_ALLOC (NULL
);
492 bitmap_set_bit (debug
->to_rescan
, INSN_UID (DF_REF_INSN (cur
->use
)));