1 /* Data flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
24 #include "coretypes.h"
27 #include "pointer-set.h"
31 #include "hard-reg-set.h"
32 #include "basic-block.h"
37 #include "langhooks.h"
40 #include "diagnostic.h"
41 #include "tree-dump.h"
42 #include "tree-gimple.h"
43 #include "tree-flow.h"
44 #include "tree-inline.h"
45 #include "tree-pass.h"
50 /* Build and maintain data flow information for trees. */
52 /* Counters used to display DFA and SSA statistics. */
67 /* Local functions. */
68 static void collect_dfa_stats (struct dfa_stats_d
*);
69 static tree
collect_dfa_stats_r (tree
*, int *, void *);
70 static tree
find_vars_r (tree
*, int *, void *);
73 /*---------------------------------------------------------------------------
74 Dataflow analysis (DFA) routines
75 ---------------------------------------------------------------------------*/
76 /* Find all the variables referenced in the function. This function
77 builds the global arrays REFERENCED_VARS and CALL_CLOBBERED_VARS.
79 Note that this function does not look for statement operands, it simply
80 determines what variables are referenced in the program and detects
81 various attributes for each variable used by alias analysis and the
85 find_referenced_vars (void)
88 block_stmt_iterator si
;
91 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
93 tree
*stmt_p
= bsi_stmt_ptr (si
);
94 walk_tree (stmt_p
, find_vars_r
, NULL
, NULL
);
100 struct tree_opt_pass pass_referenced_vars
=
104 find_referenced_vars
, /* execute */
107 0, /* static_pass_number */
108 TV_FIND_REFERENCED_VARS
, /* tv_id */
109 PROP_gimple_leh
| PROP_cfg
, /* properties_required */
110 PROP_referenced_vars
, /* properties_provided */
111 0, /* properties_destroyed */
112 0, /* todo_flags_start */
113 0, /* todo_flags_finish */
118 /*---------------------------------------------------------------------------
120 ---------------------------------------------------------------------------*/
121 /* Create a new annotation for a _DECL node T. */
124 create_var_ann (tree t
)
127 struct static_var_ann_d
*sann
= NULL
;
130 gcc_assert (DECL_P (t
));
131 gcc_assert (!t
->base
.ann
|| t
->base
.ann
->common
.type
== VAR_ANN
);
133 if (!MTAG_P (t
) && (TREE_STATIC (t
) || DECL_EXTERNAL (t
)))
135 sann
= GGC_CNEW (struct static_var_ann_d
);
139 ann
= GGC_CNEW (struct var_ann_d
);
141 ann
->common
.type
= VAR_ANN
;
143 if (!MTAG_P (t
) && (TREE_STATIC (t
) || DECL_EXTERNAL (t
)))
146 sann
->uid
= DECL_UID (t
);
147 slot
= htab_find_slot_with_hash (gimple_var_anns (cfun
),
148 t
, DECL_UID (t
), INSERT
);
153 t
->base
.ann
= (tree_ann_t
) ann
;
158 /* Create a new annotation for a FUNCTION_DECL node T. */
161 create_function_ann (tree t
)
166 gcc_assert (TREE_CODE (t
) == FUNCTION_DECL
);
167 gcc_assert (!t
->base
.ann
|| t
->base
.ann
->common
.type
== FUNCTION_ANN
);
169 ann
= ggc_alloc (sizeof (*ann
));
170 memset ((void *) ann
, 0, sizeof (*ann
));
172 ann
->common
.type
= FUNCTION_ANN
;
174 t
->base
.ann
= (tree_ann_t
) ann
;
179 /* Create a new annotation for a statement node T. */
182 create_stmt_ann (tree t
)
186 gcc_assert (is_gimple_stmt (t
));
187 gcc_assert (!t
->base
.ann
|| t
->base
.ann
->common
.type
== STMT_ANN
);
189 ann
= GGC_CNEW (struct stmt_ann_d
);
191 ann
->common
.type
= STMT_ANN
;
193 /* Since we just created the annotation, mark the statement modified. */
194 ann
->modified
= true;
196 t
->base
.ann
= (tree_ann_t
) ann
;
201 /* Create a new annotation for a tree T. */
204 create_tree_common_ann (tree t
)
206 tree_ann_common_t ann
;
209 gcc_assert (!t
->base
.ann
|| t
->base
.ann
->common
.type
== TREE_ANN_COMMON
);
211 ann
= GGC_CNEW (struct tree_ann_common_d
);
213 ann
->type
= TREE_ANN_COMMON
;
214 t
->base
.ann
= (tree_ann_t
) ann
;
219 /* Build a temporary. Make sure and register it to be renamed. */
222 make_rename_temp (tree type
, const char *prefix
)
224 tree t
= create_tmp_var (type
, prefix
);
226 if (TREE_CODE (TREE_TYPE (t
)) == COMPLEX_TYPE
227 || TREE_CODE (TREE_TYPE (t
)) == VECTOR_TYPE
)
228 DECL_GIMPLE_REG_P (t
) = 1;
230 if (gimple_referenced_vars (cfun
))
232 add_referenced_var (t
);
233 mark_sym_for_renaming (t
);
241 /*---------------------------------------------------------------------------
243 ---------------------------------------------------------------------------*/
244 /* Dump the list of all the referenced variables in the current function to
248 dump_referenced_vars (FILE *file
)
251 referenced_var_iterator rvi
;
253 fprintf (file
, "\nReferenced variables in %s: %u\n\n",
254 get_name (current_function_decl
), (unsigned) num_referenced_vars
);
256 FOR_EACH_REFERENCED_VAR (var
, rvi
)
258 fprintf (file
, "Variable: ");
259 dump_variable (file
, var
);
260 fprintf (file
, "\n");
265 /* Dump the list of all the referenced variables to stderr. */
268 debug_referenced_vars (void)
270 dump_referenced_vars (stderr
);
274 /* Dump sub-variables for VAR to FILE. */
277 dump_subvars_for (FILE *file
, tree var
)
279 subvar_t sv
= get_subvars_for_var (var
);
284 fprintf (file
, "{ ");
286 for (; sv
; sv
= sv
->next
)
288 print_generic_expr (file
, sv
->var
, dump_flags
);
296 /* Dumb sub-variables for VAR to stderr. */
299 debug_subvars_for (tree var
)
301 dump_subvars_for (stderr
, var
);
305 /* Dump variable VAR and its may-aliases to FILE. */
308 dump_variable (FILE *file
, tree var
)
312 if (TREE_CODE (var
) == SSA_NAME
)
314 if (POINTER_TYPE_P (TREE_TYPE (var
)))
315 dump_points_to_info_for (file
, var
);
316 var
= SSA_NAME_VAR (var
);
319 if (var
== NULL_TREE
)
321 fprintf (file
, "<nil>");
325 print_generic_expr (file
, var
, dump_flags
);
329 fprintf (file
, ", UID %u", (unsigned) DECL_UID (var
));
331 fprintf (file
, ", ");
332 print_generic_expr (file
, TREE_TYPE (var
), dump_flags
);
334 if (ann
&& ann
->symbol_mem_tag
)
336 fprintf (file
, ", symbol memory tag: ");
337 print_generic_expr (file
, ann
->symbol_mem_tag
, dump_flags
);
340 if (ann
&& ann
->is_aliased
)
341 fprintf (file
, ", is aliased");
343 if (TREE_ADDRESSABLE (var
))
344 fprintf (file
, ", is addressable");
346 if (is_global_var (var
))
347 fprintf (file
, ", is global");
349 if (TREE_THIS_VOLATILE (var
))
350 fprintf (file
, ", is volatile");
352 if (is_call_clobbered (var
))
354 var_ann_t va
= var_ann (var
);
355 unsigned int escape_mask
= va
->escape_mask
;
357 fprintf (file
, ", call clobbered");
358 fprintf (file
, " (");
359 if (escape_mask
& ESCAPE_STORED_IN_GLOBAL
)
360 fprintf (file
, ", stored in global");
361 if (escape_mask
& ESCAPE_TO_ASM
)
362 fprintf (file
, ", goes through ASM");
363 if (escape_mask
& ESCAPE_TO_CALL
)
364 fprintf (file
, ", passed to call");
365 if (escape_mask
& ESCAPE_BAD_CAST
)
366 fprintf (file
, ", bad cast");
367 if (escape_mask
& ESCAPE_TO_RETURN
)
368 fprintf (file
, ", returned from func");
369 if (escape_mask
& ESCAPE_TO_PURE_CONST
)
370 fprintf (file
, ", passed to pure/const");
371 if (escape_mask
& ESCAPE_IS_GLOBAL
)
372 fprintf (file
, ", is global var");
373 if (escape_mask
& ESCAPE_IS_PARM
)
374 fprintf (file
, ", is incoming pointer");
375 if (escape_mask
& ESCAPE_UNKNOWN
)
376 fprintf (file
, ", unknown escape");
377 fprintf (file
, " )");
380 if (gimple_default_def (cfun
, var
))
382 fprintf (file
, ", default def: ");
383 print_generic_expr (file
, gimple_default_def (cfun
, var
), dump_flags
);
386 if (may_aliases (var
))
388 fprintf (file
, ", may aliases: ");
389 dump_may_aliases_for (file
, var
);
392 if (get_subvars_for_var (var
))
394 fprintf (file
, ", sub-vars: ");
395 dump_subvars_for (file
, var
);
398 if (!is_gimple_reg (var
))
400 if (memory_partition (var
))
402 fprintf (file
, ", belongs to partition: ");
403 print_generic_expr (file
, memory_partition (var
), dump_flags
);
406 if (TREE_CODE (var
) == MEMORY_PARTITION_TAG
)
408 fprintf (file
, ", partition symbols: ");
409 dump_decl_set (file
, MPT_SYMBOLS (var
));
413 fprintf (file
, "\n");
417 /* Dump variable VAR and its may-aliases to stderr. */
420 debug_variable (tree var
)
422 dump_variable (stderr
, var
);
426 /* Dump various DFA statistics to FILE. */
429 dump_dfa_stats (FILE *file
)
431 struct dfa_stats_d dfa_stats
;
433 unsigned long size
, total
= 0;
434 const char * const fmt_str
= "%-30s%-13s%12s\n";
435 const char * const fmt_str_1
= "%-30s%13lu%11lu%c\n";
436 const char * const fmt_str_3
= "%-43s%11lu%c\n";
438 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
440 collect_dfa_stats (&dfa_stats
);
442 fprintf (file
, "\nDFA Statistics for %s\n\n", funcname
);
444 fprintf (file
, "---------------------------------------------------------\n");
445 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
446 fprintf (file
, fmt_str
, "", " instances ", "used ");
447 fprintf (file
, "---------------------------------------------------------\n");
449 size
= num_referenced_vars
* sizeof (tree
);
451 fprintf (file
, fmt_str_1
, "Referenced variables", (unsigned long)num_referenced_vars
,
452 SCALE (size
), LABEL (size
));
454 size
= dfa_stats
.num_stmt_anns
* sizeof (struct stmt_ann_d
);
456 fprintf (file
, fmt_str_1
, "Statements annotated", dfa_stats
.num_stmt_anns
,
457 SCALE (size
), LABEL (size
));
459 size
= dfa_stats
.num_var_anns
* sizeof (struct var_ann_d
);
461 fprintf (file
, fmt_str_1
, "Variables annotated", dfa_stats
.num_var_anns
,
462 SCALE (size
), LABEL (size
));
464 size
= dfa_stats
.num_uses
* sizeof (tree
*);
466 fprintf (file
, fmt_str_1
, "USE operands", dfa_stats
.num_uses
,
467 SCALE (size
), LABEL (size
));
469 size
= dfa_stats
.num_defs
* sizeof (tree
*);
471 fprintf (file
, fmt_str_1
, "DEF operands", dfa_stats
.num_defs
,
472 SCALE (size
), LABEL (size
));
474 size
= dfa_stats
.num_vuses
* sizeof (tree
*);
476 fprintf (file
, fmt_str_1
, "VUSE operands", dfa_stats
.num_vuses
,
477 SCALE (size
), LABEL (size
));
479 size
= dfa_stats
.num_vdefs
* sizeof (tree
*);
481 fprintf (file
, fmt_str_1
, "VDEF operands", dfa_stats
.num_vdefs
,
482 SCALE (size
), LABEL (size
));
484 size
= dfa_stats
.num_phis
* sizeof (struct tree_phi_node
);
486 fprintf (file
, fmt_str_1
, "PHI nodes", dfa_stats
.num_phis
,
487 SCALE (size
), LABEL (size
));
489 size
= dfa_stats
.num_phi_args
* sizeof (struct phi_arg_d
);
491 fprintf (file
, fmt_str_1
, "PHI arguments", dfa_stats
.num_phi_args
,
492 SCALE (size
), LABEL (size
));
494 fprintf (file
, "---------------------------------------------------------\n");
495 fprintf (file
, fmt_str_3
, "Total memory used by DFA/SSA data", SCALE (total
),
497 fprintf (file
, "---------------------------------------------------------\n");
498 fprintf (file
, "\n");
500 if (dfa_stats
.num_phis
)
501 fprintf (file
, "Average number of arguments per PHI node: %.1f (max: %d)\n",
502 (float) dfa_stats
.num_phi_args
/ (float) dfa_stats
.num_phis
,
503 dfa_stats
.max_num_phi_args
);
505 fprintf (file
, "\n");
509 /* Dump DFA statistics on stderr. */
512 debug_dfa_stats (void)
514 dump_dfa_stats (stderr
);
518 /* Collect DFA statistics and store them in the structure pointed to by
522 collect_dfa_stats (struct dfa_stats_d
*dfa_stats_p
)
524 struct pointer_set_t
*pset
;
526 block_stmt_iterator i
;
528 gcc_assert (dfa_stats_p
);
530 memset ((void *)dfa_stats_p
, 0, sizeof (struct dfa_stats_d
));
532 /* Walk all the trees in the function counting references. Start at
533 basic block NUM_FIXED_BLOCKS, but don't stop at block boundaries. */
534 pset
= pointer_set_create ();
536 for (i
= bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
537 !bsi_end_p (i
); bsi_next (&i
))
538 walk_tree (bsi_stmt_ptr (i
), collect_dfa_stats_r
, (void *) dfa_stats_p
,
541 pointer_set_destroy (pset
);
546 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
548 dfa_stats_p
->num_phis
++;
549 dfa_stats_p
->num_phi_args
+= PHI_NUM_ARGS (phi
);
550 if (PHI_NUM_ARGS (phi
) > dfa_stats_p
->max_num_phi_args
)
551 dfa_stats_p
->max_num_phi_args
= PHI_NUM_ARGS (phi
);
557 /* Callback for walk_tree to collect DFA statistics for a tree and its
561 collect_dfa_stats_r (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
565 struct dfa_stats_d
*dfa_stats_p
= (struct dfa_stats_d
*)data
;
569 switch (ann_type (t
->base
.ann
))
573 dfa_stats_p
->num_stmt_anns
++;
574 dfa_stats_p
->num_defs
+= NUM_SSA_OPERANDS (t
, SSA_OP_DEF
);
575 dfa_stats_p
->num_uses
+= NUM_SSA_OPERANDS (t
, SSA_OP_USE
);
576 dfa_stats_p
->num_vdefs
+= NUM_SSA_OPERANDS (t
, SSA_OP_VDEF
);
577 dfa_stats_p
->num_vuses
+= NUM_SSA_OPERANDS (t
, SSA_OP_VUSE
);
582 dfa_stats_p
->num_var_anns
++;
594 /*---------------------------------------------------------------------------
595 Miscellaneous helpers
596 ---------------------------------------------------------------------------*/
597 /* Callback for walk_tree. Used to collect variables referenced in
601 find_vars_r (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
603 /* If T is a regular variable that the optimizers are interested
604 in, add it to the list of variables. */
606 add_referenced_var (*tp
);
608 /* Type, _DECL and constant nodes have no interesting children.
610 else if (IS_TYPE_OR_DECL_P (*tp
) || CONSTANT_CLASS_P (*tp
))
616 /* Lookup UID in the referenced_vars hashtable and return the associated
620 referenced_var_lookup (unsigned int uid
)
622 struct int_tree_map
*h
, in
;
624 h
= (struct int_tree_map
*) htab_find_with_hash (gimple_referenced_vars (cfun
),
626 gcc_assert (h
|| uid
== 0);
632 /* Check if TO is in the referenced_vars hash table and insert it if not.
633 Return true if it required insertion. */
636 referenced_var_check_and_insert (tree to
)
638 struct int_tree_map
*h
, in
;
640 unsigned int uid
= DECL_UID (to
);
644 h
= (struct int_tree_map
*) htab_find_with_hash (gimple_referenced_vars (cfun
),
649 /* DECL_UID has already been entered in the table. Verify that it is
650 the same entry as TO. See PR 27793. */
651 gcc_assert (h
->to
== to
);
655 h
= GGC_NEW (struct int_tree_map
);
658 loc
= htab_find_slot_with_hash (gimple_referenced_vars (cfun
),
660 *(struct int_tree_map
**) loc
= h
;
664 /* Lookup VAR UID in the default_defs hashtable and return the associated
668 gimple_default_def (struct function
*fn
, tree var
)
670 struct int_tree_map
*h
, in
;
671 gcc_assert (SSA_VAR_P (var
));
672 in
.uid
= DECL_UID (var
);
673 h
= (struct int_tree_map
*) htab_find_with_hash (DEFAULT_DEFS (fn
),
681 /* Insert the pair VAR's UID, DEF into the default_defs hashtable. */
684 set_default_def (tree var
, tree def
)
686 struct int_tree_map in
;
687 struct int_tree_map
*h
;
690 gcc_assert (SSA_VAR_P (var
));
691 in
.uid
= DECL_UID (var
);
692 if (!def
&& gimple_default_def (cfun
, var
))
694 loc
= htab_find_slot_with_hash (DEFAULT_DEFS (cfun
), &in
,
695 DECL_UID (var
), INSERT
);
696 htab_remove_elt (DEFAULT_DEFS (cfun
), *loc
);
699 gcc_assert (!def
|| TREE_CODE (def
) == SSA_NAME
);
700 loc
= htab_find_slot_with_hash (DEFAULT_DEFS (cfun
), &in
,
701 DECL_UID (var
), INSERT
);
703 /* Default definition might be changed by tail call optimization. */
706 h
= GGC_NEW (struct int_tree_map
);
707 h
->uid
= DECL_UID (var
);
709 *(struct int_tree_map
**) loc
= h
;
713 h
= (struct int_tree_map
*) *loc
;
714 SSA_NAME_IS_DEFAULT_DEF (h
->to
) = false;
718 /* Mark DEF as the default definition for VAR. */
719 SSA_NAME_IS_DEFAULT_DEF (def
) = true;
722 /* Add VAR to the list of referenced variables if it isn't already there. */
725 add_referenced_var (tree var
)
729 v_ann
= get_var_ann (var
);
730 gcc_assert (DECL_P (var
));
732 /* Insert VAR into the referenced_vars has table if it isn't present. */
733 if (referenced_var_check_and_insert (var
))
735 /* This is the first time we found this variable, annotate it with
736 attributes that are intrinsic to the variable. */
738 /* Tag's don't have DECL_INITIAL. */
742 /* Scan DECL_INITIAL for pointer variables as they may contain
743 address arithmetic referencing the address of other
745 Even non-constant intializers need to be walked, because
746 IPA passes might prove that their are invariant later on. */
747 if (DECL_INITIAL (var
)
748 /* Initializers of external variables are not useful to the
750 && !DECL_EXTERNAL (var
))
751 walk_tree (&DECL_INITIAL (var
), find_vars_r
, NULL
, 0);
755 /* Remove VAR from the list. */
758 remove_referenced_var (tree var
)
761 struct int_tree_map in
;
763 unsigned int uid
= DECL_UID (var
);
765 clear_call_clobbered (var
);
766 v_ann
= get_var_ann (var
);
768 var
->base
.ann
= NULL
;
769 gcc_assert (DECL_P (var
));
772 loc
= htab_find_slot_with_hash (gimple_referenced_vars (cfun
), &in
, uid
,
775 htab_clear_slot (gimple_referenced_vars (cfun
), loc
);
779 /* Return the virtual variable associated to the non-scalar variable VAR. */
782 get_virtual_var (tree var
)
786 if (TREE_CODE (var
) == SSA_NAME
)
787 var
= SSA_NAME_VAR (var
);
789 while (TREE_CODE (var
) == REALPART_EXPR
|| TREE_CODE (var
) == IMAGPART_EXPR
790 || handled_component_p (var
))
791 var
= TREE_OPERAND (var
, 0);
793 /* Treating GIMPLE registers as virtual variables makes no sense.
794 Also complain if we couldn't extract a _DECL out of the original
796 gcc_assert (SSA_VAR_P (var
));
797 gcc_assert (!is_gimple_reg (var
));
802 /* Mark all the naked symbols in STMT for SSA renaming.
804 NOTE: This function should only be used for brand new statements.
805 If the caller is modifying an existing statement, it should use the
806 combination push_stmt_changes/pop_stmt_changes. */
809 mark_symbols_for_renaming (tree stmt
)
816 /* Mark all the operands for renaming. */
817 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_ALL_OPERANDS
)
819 mark_sym_for_renaming (op
);
823 /* Find all variables within the gimplified statement that were not previously
824 visible to the function and add them to the referenced variables list. */
827 find_new_referenced_vars_1 (tree
*tp
, int *walk_subtrees
,
828 void *data ATTRIBUTE_UNUSED
)
832 if (TREE_CODE (t
) == VAR_DECL
&& !var_ann (t
))
834 add_referenced_var (t
);
835 mark_sym_for_renaming (t
);
838 if (IS_TYPE_OR_DECL_P (t
))
845 find_new_referenced_vars (tree
*stmt_p
)
847 walk_tree (stmt_p
, find_new_referenced_vars_1
, NULL
, NULL
);
851 /* If EXP is a handled component reference for a structure, return the
852 base variable. The access range is delimited by bit positions *POFFSET and
853 *POFFSET + *PMAX_SIZE. The access size is *PSIZE bits. If either
854 *PSIZE or *PMAX_SIZE is -1, they could not be determined. If *PSIZE
855 and *PMAX_SIZE are equal, the access is non-variable. */
858 get_ref_base_and_extent (tree exp
, HOST_WIDE_INT
*poffset
,
859 HOST_WIDE_INT
*psize
,
860 HOST_WIDE_INT
*pmax_size
)
862 HOST_WIDE_INT bitsize
= -1;
863 HOST_WIDE_INT maxsize
= -1;
864 tree size_tree
= NULL_TREE
;
865 tree bit_offset
= bitsize_zero_node
;
866 bool seen_variable_array_ref
= false;
868 gcc_assert (!SSA_VAR_P (exp
));
870 /* First get the final access size from just the outermost expression. */
871 if (TREE_CODE (exp
) == COMPONENT_REF
)
872 size_tree
= DECL_SIZE (TREE_OPERAND (exp
, 1));
873 else if (TREE_CODE (exp
) == BIT_FIELD_REF
)
874 size_tree
= TREE_OPERAND (exp
, 1);
877 enum machine_mode mode
= TYPE_MODE (TREE_TYPE (exp
));
879 size_tree
= TYPE_SIZE (TREE_TYPE (exp
));
881 bitsize
= GET_MODE_BITSIZE (mode
);
883 if (size_tree
!= NULL_TREE
)
885 if (! host_integerp (size_tree
, 1))
888 bitsize
= TREE_INT_CST_LOW (size_tree
);
891 /* Initially, maxsize is the same as the accessed element size.
892 In the following it will only grow (or become -1). */
895 /* Compute cumulative bit-offset for nested component-refs and array-refs,
896 and find the ultimate containing object. */
899 switch (TREE_CODE (exp
))
902 bit_offset
= size_binop (PLUS_EXPR
, bit_offset
,
903 TREE_OPERAND (exp
, 2));
908 tree field
= TREE_OPERAND (exp
, 1);
909 tree this_offset
= component_ref_field_offset (exp
);
911 if (this_offset
&& TREE_CODE (this_offset
) == INTEGER_CST
)
913 this_offset
= size_binop (MULT_EXPR
,
914 fold_convert (bitsizetype
,
917 bit_offset
= size_binop (PLUS_EXPR
,
918 bit_offset
, this_offset
);
919 bit_offset
= size_binop (PLUS_EXPR
, bit_offset
,
920 DECL_FIELD_BIT_OFFSET (field
));
924 tree csize
= TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp
, 0)));
925 /* We need to adjust maxsize to the whole structure bitsize.
926 But we can subtract any constant offset seen sofar,
927 because that would get us out of the structure otherwise. */
929 && csize
&& host_integerp (csize
, 1))
931 maxsize
= (TREE_INT_CST_LOW (csize
)
932 - TREE_INT_CST_LOW (bit_offset
));
941 case ARRAY_RANGE_REF
:
943 tree index
= TREE_OPERAND (exp
, 1);
944 tree low_bound
= array_ref_low_bound (exp
);
945 tree unit_size
= array_ref_element_size (exp
);
947 if (! integer_zerop (low_bound
))
948 index
= fold_build2 (MINUS_EXPR
, TREE_TYPE (index
),
950 index
= size_binop (MULT_EXPR
,
951 fold_convert (sizetype
, index
), unit_size
);
952 if (TREE_CODE (index
) == INTEGER_CST
)
954 index
= size_binop (MULT_EXPR
,
955 fold_convert (bitsizetype
, index
),
957 bit_offset
= size_binop (PLUS_EXPR
, bit_offset
, index
);
959 /* An array ref with a constant index up in the structure
960 hierarchy will constrain the size of any variable array ref
961 lower in the access hierarchy. */
962 seen_variable_array_ref
= false;
966 tree asize
= TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp
, 0)));
967 /* We need to adjust maxsize to the whole array bitsize.
968 But we can subtract any constant offset seen sofar,
969 because that would get us outside of the array otherwise. */
971 && asize
&& host_integerp (asize
, 1))
973 maxsize
= (TREE_INT_CST_LOW (asize
)
974 - TREE_INT_CST_LOW (bit_offset
));
979 /* Remember that we have seen an array ref with a variable
981 seen_variable_array_ref
= true;
990 bit_offset
= size_binop (PLUS_EXPR
, bit_offset
,
991 bitsize_int (bitsize
));
994 case VIEW_CONVERT_EXPR
:
995 /* ??? We probably should give up here and bail out. */
1002 exp
= TREE_OPERAND (exp
, 0);
1006 /* We need to deal with variable arrays ending structures such as
1007 struct { int length; int a[1]; } x; x.a[d]
1008 struct { struct { int a; int b; } a[1]; } x; x.a[d].a
1009 struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0]
1010 where we do not know maxsize for variable index accesses to
1011 the array. The simplest way to conservatively deal with this
1012 is to punt in the case that offset + maxsize reaches the
1013 base type boundary. */
1014 if (seen_variable_array_ref
1016 && host_integerp (TYPE_SIZE (TREE_TYPE (exp
)), 1)
1017 && TREE_INT_CST_LOW (bit_offset
) + maxsize
1018 == TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp
))))
1021 /* ??? Due to negative offsets in ARRAY_REF we can end up with
1022 negative bit_offset here. We might want to store a zero offset
1024 *poffset
= TREE_INT_CST_LOW (bit_offset
);
1026 *pmax_size
= maxsize
;