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. */
37 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
);
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;
146 pair
->to
= cleanup_auto_inc_dec (pair
->to
, VOIDmode
);
148 pair
->to
= copy_rtx (pair
->to
);
150 pair
->to
= make_compound_operation (pair
->to
, SET
);
153 return copy_rtx (pair
->to
);
156 /* Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN
157 and LAST, not including INSN, but including LAST. Also stop at the end
158 of THIS_BASIC_BLOCK. */
161 propagate_for_debug (rtx insn
, rtx last
, rtx dest
, rtx src
,
162 basic_block this_basic_block
)
164 rtx next
, loc
, end
= NEXT_INSN (BB_END (this_basic_block
));
166 struct rtx_subst_pair p
;
170 next
= NEXT_INSN (insn
);
171 last
= NEXT_INSN (last
);
172 while (next
!= last
&& next
!= end
)
175 next
= NEXT_INSN (insn
);
176 if (DEBUG_INSN_P (insn
))
178 loc
= simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn
),
179 dest
, propagate_for_debug_subst
, &p
);
180 if (loc
== INSN_VAR_LOCATION_LOC (insn
))
182 INSN_VAR_LOCATION_LOC (insn
) = loc
;
183 df_insn_rescan (insn
);
188 /* Initialize DEBUG to an empty list, and clear USED, if given. */
190 dead_debug_init (struct dead_debug
*debug
, bitmap used
)
194 debug
->to_rescan
= NULL
;
199 /* Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
200 each reset insn. DEBUG is not otherwise modified. If HEAD is
201 DEBUG->head, DEBUG->head will be set to NULL at the end.
202 Otherwise, entries from DEBUG->head that pertain to reset insns
203 will be removed, and only then rescanned. */
206 dead_debug_reset_uses (struct dead_debug
*debug
, struct dead_debug_use
*head
)
208 bool got_head
= (debug
->head
== head
);
210 struct dead_debug_use
**tailp
= &debug
->head
;
211 struct dead_debug_use
*cur
;
218 rescan
= BITMAP_ALLOC (NULL
);
222 struct dead_debug_use
*next
= head
->next
;
225 insn
= DF_REF_INSN (head
->use
);
226 if (!next
|| DF_REF_INSN (next
->use
) != insn
)
228 INSN_VAR_LOCATION_LOC (insn
) = gen_rtx_UNKNOWN_VAR_LOC ();
230 df_insn_rescan_debug_internal (insn
);
232 bitmap_set_bit (rescan
, INSN_UID (insn
));
233 if (debug
->to_rescan
)
234 bitmap_clear_bit (debug
->to_rescan
, INSN_UID (insn
));
246 while ((cur
= *tailp
))
247 if (bitmap_bit_p (rescan
, INSN_UID (DF_REF_INSN (cur
->use
))))
255 EXECUTE_IF_SET_IN_BITMAP (rescan
, 0, uid
, bi
)
257 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
259 df_insn_rescan_debug_internal (insn_info
->insn
);
262 BITMAP_FREE (rescan
);
265 /* Reset all debug insns with pending uses. Release the bitmap in it,
266 unless it is USED. USED must be the same bitmap passed to
269 dead_debug_finish (struct dead_debug
*debug
, bitmap used
)
271 if (debug
->used
!= used
)
272 BITMAP_FREE (debug
->used
);
274 dead_debug_reset_uses (debug
, debug
->head
);
276 if (debug
->to_rescan
)
281 EXECUTE_IF_SET_IN_BITMAP (debug
->to_rescan
, 0, uid
, bi
)
283 struct df_insn_info
*insn_info
= DF_INSN_UID_SAFE_GET (uid
);
285 df_insn_rescan (insn_info
->insn
);
287 BITMAP_FREE (debug
->to_rescan
);
291 /* Add USE to DEBUG. It must be a dead reference to UREGNO in a debug
292 insn. Create a bitmap for DEBUG as needed. */
294 dead_debug_add (struct dead_debug
*debug
, df_ref use
, unsigned int uregno
)
296 struct dead_debug_use
*newddu
= XNEW (struct dead_debug_use
);
299 newddu
->next
= debug
->head
;
300 debug
->head
= newddu
;
303 debug
->used
= BITMAP_ALLOC (NULL
);
305 /* ??? If we dealt with split multi-registers below, we should set
306 all registers for the used mode in case of hardware
308 bitmap_set_bit (debug
->used
, uregno
);
311 /* If UREGNO is referenced by any entry in DEBUG, emit a debug insn
312 before or after INSN (depending on WHERE), that binds a debug temp
313 to the widest-mode use of UREGNO, if WHERE is *_WITH_REG, or the
314 value stored in UREGNO by INSN otherwise, and replace all uses of
315 UREGNO in DEBUG with uses of the debug temp. INSN must be where
316 UREGNO dies, if WHERE is *_BEFORE_*, or where it is set otherwise.
317 Return the number of debug insns emitted. */
319 dead_debug_insert_temp (struct dead_debug
*debug
, unsigned int uregno
,
320 rtx insn
, enum debug_temp_where where
)
322 struct dead_debug_use
**tailp
= &debug
->head
;
323 struct dead_debug_use
*cur
;
324 struct dead_debug_use
*uses
= NULL
;
325 struct dead_debug_use
**usesp
= &uses
;
331 if (!debug
->used
|| !bitmap_clear_bit (debug
->used
, uregno
))
334 /* Move all uses of uregno from debug->head to uses, setting mode to
335 the widest referenced mode. */
336 while ((cur
= *tailp
))
338 if (DF_REF_REGNO (cur
->use
) == uregno
)
345 || (GET_MODE_BITSIZE (GET_MODE (reg
))
346 < GET_MODE_BITSIZE (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)))))
347 reg
= *DF_REF_REAL_LOC (cur
->use
);
350 tailp
= &(*tailp
)->next
;
353 /* We may have dangling bits in debug->used for registers that were part
354 of a multi-register use, one component of which has been reset. */
357 gcc_checking_assert (!uses
);
361 gcc_checking_assert (uses
);
364 /* Recover the expression INSN stores in REG. */
365 if (where
== DEBUG_TEMP_BEFORE_WITH_VALUE
)
367 rtx set
= single_set (insn
);
372 dest
= SET_DEST (set
);
374 /* Lose if the REG-setting insn is a CALL. */
375 if (GET_CODE (src
) == CALL
)
387 /* ??? Should we try to extract it from a PARALLEL? */
390 /* Cool, it's the same REG, we can use SRC. */
391 else if (dest
== reg
)
392 breg
= copy_rtx (src
);
393 else if (REG_P (dest
))
395 /* Hmm... Something's fishy, we should be setting REG here. */
396 if (REGNO (dest
) != REGNO (reg
))
398 /* If we're not overwriting all the hardware registers that
399 setting REG in its mode would, we won't know what to bind
400 the debug temp to. ??? We could bind the debug_expr to a
401 CONCAT or PARALLEL with the split multi-registers, and
402 replace them as we found the corresponding sets. */
403 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
404 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
405 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
407 /* Ok, it's the same (hardware) REG, but with a different
408 mode, so SUBREG it. */
410 breg
= lowpart_subreg (GET_MODE (reg
), copy_rtx (src
),
413 else if (GET_CODE (dest
) == SUBREG
)
415 /* We should be setting REG here. Lose. */
416 if (REGNO (SUBREG_REG (dest
)) != REGNO (reg
))
418 /* Lose if we're setting something other than the lowpart of
420 else if (!subreg_lowpart_p (dest
))
422 /* If we're not overwriting all the hardware registers that
423 setting REG in its mode would, we won't know what to bind
424 the debug temp to. */
425 else if (REGNO (reg
) < FIRST_PSEUDO_REGISTER
426 && (hard_regno_nregs
[REGNO (reg
)][GET_MODE (reg
)]
427 != hard_regno_nregs
[REGNO (reg
)][GET_MODE (dest
)]))
429 /* Yay, we can use SRC, just adjust its mode. */
431 breg
= lowpart_subreg (GET_MODE (reg
), copy_rtx (src
),
434 /* Oh well, we're out of luck. */
438 /* We couldn't figure out the value stored in REG, so reset all
439 of its pending debug uses. */
442 dead_debug_reset_uses (debug
, uses
);
447 /* If there's a single (debug) use of an otherwise unused REG, and
448 the debug use is not part of a larger expression, then it
449 probably doesn't make sense to introduce a new debug temp. */
450 if (where
== DEBUG_TEMP_AFTER_WITH_REG
&& !uses
->next
)
452 rtx next
= DF_REF_INSN (uses
->use
);
454 if (DEBUG_INSN_P (next
) && reg
== INSN_VAR_LOCATION_LOC (next
))
461 /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */
462 dval
= make_debug_expr_from_rtl (reg
);
464 /* Emit a debug bind insn before the insn in which reg dies. */
465 bind
= gen_rtx_VAR_LOCATION (GET_MODE (reg
),
466 DEBUG_EXPR_TREE_DECL (dval
), breg
,
467 VAR_INIT_STATUS_INITIALIZED
);
469 if (where
== DEBUG_TEMP_AFTER_WITH_REG
)
470 bind
= emit_debug_insn_after (bind
, insn
);
472 bind
= emit_debug_insn_before (bind
, insn
);
473 df_insn_rescan (bind
);
475 /* Adjust all uses. */
478 if (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)) == GET_MODE (reg
))
479 *DF_REF_REAL_LOC (cur
->use
) = dval
;
481 *DF_REF_REAL_LOC (cur
->use
)
482 = gen_lowpart_SUBREG (GET_MODE (*DF_REF_REAL_LOC (cur
->use
)), dval
);
483 /* ??? Should we simplify subreg of subreg? */
484 if (debug
->to_rescan
== NULL
)
485 debug
->to_rescan
= BITMAP_ALLOC (NULL
);
486 bitmap_set_bit (debug
->to_rescan
, INSN_UID (DF_REF_INSN (cur
->use
)));