1 /* Data flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007 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 3, 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 COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
26 #include "pointer-set.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
36 #include "langhooks.h"
39 #include "diagnostic.h"
40 #include "tree-dump.h"
41 #include "tree-gimple.h"
42 #include "tree-flow.h"
43 #include "tree-inline.h"
44 #include "tree-pass.h"
49 /* Build and maintain data flow information for trees. */
51 /* Counters used to display DFA and SSA statistics. */
66 /* Local functions. */
67 static void collect_dfa_stats (struct dfa_stats_d *);
68 static tree collect_dfa_stats_r (tree *, int *, void *);
69 static tree find_vars_r (tree *, int *, void *);
72 /*---------------------------------------------------------------------------
73 Dataflow analysis (DFA) routines
74 ---------------------------------------------------------------------------*/
75 /* Find all the variables referenced in the function. This function
76 builds the global arrays REFERENCED_VARS and CALL_CLOBBERED_VARS.
78 Note that this function does not look for statement operands, it simply
79 determines what variables are referenced in the program and detects
80 various attributes for each variable used by alias analysis and the
84 find_referenced_vars (void)
87 block_stmt_iterator si;
90 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
92 tree *stmt_p = bsi_stmt_ptr (si);
93 walk_tree (stmt_p, find_vars_r, NULL, NULL);
99 struct tree_opt_pass pass_referenced_vars =
103 find_referenced_vars, /* execute */
106 0, /* static_pass_number */
107 TV_FIND_REFERENCED_VARS, /* tv_id */
108 PROP_gimple_leh | PROP_cfg, /* properties_required */
109 PROP_referenced_vars, /* properties_provided */
110 0, /* properties_destroyed */
111 0, /* todo_flags_start */
112 0, /* todo_flags_finish */
117 /*---------------------------------------------------------------------------
119 ---------------------------------------------------------------------------*/
120 /* Create a new annotation for a _DECL node T. */
123 create_var_ann (tree t)
126 struct static_var_ann_d *sann = NULL;
129 gcc_assert (DECL_P (t));
130 gcc_assert (!t->base.ann || t->base.ann->common.type == VAR_ANN);
132 if (!MTAG_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
134 sann = GGC_CNEW (struct static_var_ann_d);
138 ann = GGC_CNEW (struct var_ann_d);
140 ann->common.type = VAR_ANN;
142 if (!MTAG_P (t) && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
145 sann->uid = DECL_UID (t);
146 slot = htab_find_slot_with_hash (gimple_var_anns (cfun),
147 t, DECL_UID (t), INSERT);
152 t->base.ann = (tree_ann_t) ann;
157 /* Create a new annotation for a FUNCTION_DECL node T. */
160 create_function_ann (tree t)
165 gcc_assert (TREE_CODE (t) == FUNCTION_DECL);
166 gcc_assert (!t->base.ann || t->base.ann->common.type == FUNCTION_ANN);
168 ann = ggc_alloc (sizeof (*ann));
169 memset ((void *) ann, 0, sizeof (*ann));
171 ann->common.type = FUNCTION_ANN;
173 t->base.ann = (tree_ann_t) ann;
178 /* Create a new annotation for a statement node T. */
181 create_stmt_ann (tree t)
185 gcc_assert (is_gimple_stmt (t));
186 gcc_assert (!t->base.ann || t->base.ann->common.type == STMT_ANN);
188 ann = GGC_CNEW (struct stmt_ann_d);
190 ann->common.type = STMT_ANN;
192 /* Since we just created the annotation, mark the statement modified. */
193 ann->modified = true;
195 t->base.ann = (tree_ann_t) ann;
200 /* Create a new annotation for a tree T. */
203 create_tree_common_ann (tree t)
205 tree_ann_common_t ann;
208 gcc_assert (!t->base.ann || t->base.ann->common.type == TREE_ANN_COMMON);
210 ann = GGC_CNEW (struct tree_ann_common_d);
212 ann->type = TREE_ANN_COMMON;
213 t->base.ann = (tree_ann_t) ann;
218 /* Build a temporary. Make sure and register it to be renamed. */
221 make_rename_temp (tree type, const char *prefix)
223 tree t = create_tmp_var (type, prefix);
225 if (TREE_CODE (TREE_TYPE (t)) == COMPLEX_TYPE
226 || TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
227 DECL_GIMPLE_REG_P (t) = 1;
229 if (gimple_referenced_vars (cfun))
231 add_referenced_var (t);
232 mark_sym_for_renaming (t);
240 /*---------------------------------------------------------------------------
242 ---------------------------------------------------------------------------*/
243 /* Dump the list of all the referenced variables in the current function to
247 dump_referenced_vars (FILE *file)
250 referenced_var_iterator rvi;
252 fprintf (file, "\nReferenced variables in %s: %u\n\n",
253 get_name (current_function_decl), (unsigned) num_referenced_vars);
255 FOR_EACH_REFERENCED_VAR (var, rvi)
257 fprintf (file, "Variable: ");
258 dump_variable (file, var);
259 fprintf (file, "\n");
264 /* Dump the list of all the referenced variables to stderr. */
267 debug_referenced_vars (void)
269 dump_referenced_vars (stderr);
273 /* Dump sub-variables for VAR to FILE. */
276 dump_subvars_for (FILE *file, tree var)
278 subvar_t sv = get_subvars_for_var (var);
283 fprintf (file, "{ ");
285 for (; sv; sv = sv->next)
287 print_generic_expr (file, sv->var, dump_flags);
295 /* Dumb sub-variables for VAR to stderr. */
298 debug_subvars_for (tree var)
300 dump_subvars_for (stderr, var);
304 /* Dump variable VAR and its may-aliases to FILE. */
307 dump_variable (FILE *file, tree var)
311 if (TREE_CODE (var) == SSA_NAME)
313 if (POINTER_TYPE_P (TREE_TYPE (var)))
314 dump_points_to_info_for (file, var);
315 var = SSA_NAME_VAR (var);
318 if (var == NULL_TREE)
320 fprintf (file, "<nil>");
324 print_generic_expr (file, var, dump_flags);
328 fprintf (file, ", UID D.%u", (unsigned) DECL_UID (var));
330 fprintf (file, ", ");
331 print_generic_expr (file, TREE_TYPE (var), dump_flags);
333 if (ann && ann->symbol_mem_tag)
335 fprintf (file, ", symbol memory tag: ");
336 print_generic_expr (file, ann->symbol_mem_tag, dump_flags);
339 if (TREE_ADDRESSABLE (var))
340 fprintf (file, ", is addressable");
342 if (is_global_var (var))
343 fprintf (file, ", is global");
345 if (TREE_THIS_VOLATILE (var))
346 fprintf (file, ", is volatile");
348 if (mem_sym_stats (cfun, var))
350 mem_sym_stats_t stats = mem_sym_stats (cfun, var);
351 fprintf (file, ", direct reads: %ld", stats->num_direct_reads);
352 fprintf (file, ", direct writes: %ld", stats->num_direct_writes);
353 fprintf (file, ", indirect reads: %ld", stats->num_indirect_reads);
354 fprintf (file, ", indirect writes: %ld", stats->num_indirect_writes);
355 fprintf (file, ", read frequency: %ld", stats->frequency_reads);
356 fprintf (file, ", write frequency: %ld", stats->frequency_writes);
359 if (is_call_clobbered (var))
362 var_ann_t va = var_ann (var);
363 unsigned int escape_mask = va->escape_mask;
365 fprintf (file, ", call clobbered");
366 fprintf (file, " (");
367 if (escape_mask & ESCAPE_STORED_IN_GLOBAL)
368 { fprintf (file, "%sstored in global", s); s = ", "; }
369 if (escape_mask & ESCAPE_TO_ASM)
370 { fprintf (file, "%sgoes through ASM", s); s = ", "; }
371 if (escape_mask & ESCAPE_TO_CALL)
372 { fprintf (file, "%spassed to call", s); s = ", "; }
373 if (escape_mask & ESCAPE_BAD_CAST)
374 { fprintf (file, "%sbad cast", s); s = ", "; }
375 if (escape_mask & ESCAPE_TO_RETURN)
376 { fprintf (file, "%sreturned from func", s); s = ", "; }
377 if (escape_mask & ESCAPE_TO_PURE_CONST)
378 { fprintf (file, "%spassed to pure/const", s); s = ", "; }
379 if (escape_mask & ESCAPE_IS_GLOBAL)
380 { fprintf (file, "%sis global var", s); s = ", "; }
381 if (escape_mask & ESCAPE_IS_PARM)
382 { fprintf (file, "%sis incoming pointer", s); s = ", "; }
383 if (escape_mask & ESCAPE_UNKNOWN)
384 { fprintf (file, "%sunknown escape", s); s = ", "; }
388 if (ann->noalias_state == NO_ALIAS)
389 fprintf (file, ", NO_ALIAS (does not alias other NO_ALIAS symbols)");
390 else if (ann->noalias_state == NO_ALIAS_GLOBAL)
391 fprintf (file, ", NO_ALIAS_GLOBAL (does not alias other NO_ALIAS symbols"
392 " and global vars)");
393 else if (ann->noalias_state == NO_ALIAS_ANYTHING)
394 fprintf (file, ", NO_ALIAS_ANYTHING (does not alias any other symbols)");
396 if (gimple_default_def (cfun, var))
398 fprintf (file, ", default def: ");
399 print_generic_expr (file, gimple_default_def (cfun, var), dump_flags);
402 if (MTAG_P (var) && may_aliases (var))
404 fprintf (file, ", may aliases: ");
405 dump_may_aliases_for (file, var);
408 if (get_subvars_for_var (var))
410 fprintf (file, ", sub-vars: ");
411 dump_subvars_for (file, var);
414 if (!is_gimple_reg (var))
416 if (memory_partition (var))
418 fprintf (file, ", belongs to partition: ");
419 print_generic_expr (file, memory_partition (var), dump_flags);
422 if (TREE_CODE (var) == MEMORY_PARTITION_TAG)
424 fprintf (file, ", partition symbols: ");
425 dump_decl_set (file, MPT_SYMBOLS (var));
429 fprintf (file, "\n");
433 /* Dump variable VAR and its may-aliases to stderr. */
436 debug_variable (tree var)
438 dump_variable (stderr, var);
442 /* Dump various DFA statistics to FILE. */
445 dump_dfa_stats (FILE *file)
447 struct dfa_stats_d dfa_stats;
449 unsigned long size, total = 0;
450 const char * const fmt_str = "%-30s%-13s%12s\n";
451 const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
452 const char * const fmt_str_3 = "%-43s%11lu%c\n";
454 = lang_hooks.decl_printable_name (current_function_decl, 2);
456 collect_dfa_stats (&dfa_stats);
458 fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
460 fprintf (file, "---------------------------------------------------------\n");
461 fprintf (file, fmt_str, "", " Number of ", "Memory");
462 fprintf (file, fmt_str, "", " instances ", "used ");
463 fprintf (file, "---------------------------------------------------------\n");
465 size = num_referenced_vars * sizeof (tree);
467 fprintf (file, fmt_str_1, "Referenced variables", (unsigned long)num_referenced_vars,
468 SCALE (size), LABEL (size));
470 size = dfa_stats.num_stmt_anns * sizeof (struct stmt_ann_d);
472 fprintf (file, fmt_str_1, "Statements annotated", dfa_stats.num_stmt_anns,
473 SCALE (size), LABEL (size));
475 size = dfa_stats.num_var_anns * sizeof (struct var_ann_d);
477 fprintf (file, fmt_str_1, "Variables annotated", dfa_stats.num_var_anns,
478 SCALE (size), LABEL (size));
480 size = dfa_stats.num_uses * sizeof (tree *);
482 fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
483 SCALE (size), LABEL (size));
485 size = dfa_stats.num_defs * sizeof (tree *);
487 fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
488 SCALE (size), LABEL (size));
490 size = dfa_stats.num_vuses * sizeof (tree *);
492 fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
493 SCALE (size), LABEL (size));
495 size = dfa_stats.num_vdefs * sizeof (tree *);
497 fprintf (file, fmt_str_1, "VDEF operands", dfa_stats.num_vdefs,
498 SCALE (size), LABEL (size));
500 size = dfa_stats.num_phis * sizeof (struct tree_phi_node);
502 fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
503 SCALE (size), LABEL (size));
505 size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
507 fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
508 SCALE (size), LABEL (size));
510 fprintf (file, "---------------------------------------------------------\n");
511 fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
513 fprintf (file, "---------------------------------------------------------\n");
514 fprintf (file, "\n");
516 if (dfa_stats.num_phis)
517 fprintf (file, "Average number of arguments per PHI node: %.1f (max: %d)\n",
518 (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
519 dfa_stats.max_num_phi_args);
521 fprintf (file, "\n");
525 /* Dump DFA statistics on stderr. */
528 debug_dfa_stats (void)
530 dump_dfa_stats (stderr);
534 /* Collect DFA statistics and store them in the structure pointed to by
538 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p)
540 struct pointer_set_t *pset;
542 block_stmt_iterator i;
544 gcc_assert (dfa_stats_p);
546 memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d));
548 /* Walk all the trees in the function counting references. Start at
549 basic block NUM_FIXED_BLOCKS, but don't stop at block boundaries. */
550 pset = pointer_set_create ();
552 for (i = bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
553 !bsi_end_p (i); bsi_next (&i))
554 walk_tree (bsi_stmt_ptr (i), collect_dfa_stats_r, (void *) dfa_stats_p,
557 pointer_set_destroy (pset);
562 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
564 dfa_stats_p->num_phis++;
565 dfa_stats_p->num_phi_args += PHI_NUM_ARGS (phi);
566 if (PHI_NUM_ARGS (phi) > dfa_stats_p->max_num_phi_args)
567 dfa_stats_p->max_num_phi_args = PHI_NUM_ARGS (phi);
573 /* Callback for walk_tree to collect DFA statistics for a tree and its
577 collect_dfa_stats_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
581 struct dfa_stats_d *dfa_stats_p = (struct dfa_stats_d *)data;
585 switch (ann_type (t->base.ann))
589 dfa_stats_p->num_stmt_anns++;
590 dfa_stats_p->num_defs += NUM_SSA_OPERANDS (t, SSA_OP_DEF);
591 dfa_stats_p->num_uses += NUM_SSA_OPERANDS (t, SSA_OP_USE);
592 dfa_stats_p->num_vdefs += NUM_SSA_OPERANDS (t, SSA_OP_VDEF);
593 dfa_stats_p->num_vuses += NUM_SSA_OPERANDS (t, SSA_OP_VUSE);
598 dfa_stats_p->num_var_anns++;
610 /*---------------------------------------------------------------------------
611 Miscellaneous helpers
612 ---------------------------------------------------------------------------*/
613 /* Callback for walk_tree. Used to collect variables referenced in
617 find_vars_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
619 /* If T is a regular variable that the optimizers are interested
620 in, add it to the list of variables. */
622 add_referenced_var (*tp);
624 /* Type, _DECL and constant nodes have no interesting children.
626 else if (IS_TYPE_OR_DECL_P (*tp) || CONSTANT_CLASS_P (*tp))
632 /* Lookup UID in the referenced_vars hashtable and return the associated
636 referenced_var_lookup (unsigned int uid)
639 struct tree_decl_minimal in;
641 h = (tree) htab_find_with_hash (gimple_referenced_vars (cfun), &in, uid);
642 gcc_assert (h || uid == 0);
646 /* Check if TO is in the referenced_vars hash table and insert it if not.
647 Return true if it required insertion. */
650 referenced_var_check_and_insert (tree to)
653 struct tree_decl_minimal in;
654 unsigned int uid = DECL_UID (to);
657 h = (tree) htab_find_with_hash (gimple_referenced_vars (cfun), &in, uid);
660 /* DECL_UID has already been entered in the table. Verify that it is
661 the same entry as TO. See PR 27793. */
662 gcc_assert (h == to);
666 loc = (tree *) htab_find_slot_with_hash (gimple_referenced_vars (cfun),
672 /* Lookup VAR UID in the default_defs hashtable and return the associated
676 gimple_default_def (struct function *fn, tree var)
678 struct tree_decl_minimal ind;
679 struct tree_ssa_name in;
680 gcc_assert (SSA_VAR_P (var));
682 ind.uid = DECL_UID (var);
683 return (tree) htab_find_with_hash (DEFAULT_DEFS (fn), &in, DECL_UID (var));
686 /* Insert the pair VAR's UID, DEF into the default_defs hashtable. */
689 set_default_def (tree var, tree def)
691 struct tree_decl_minimal ind;
692 struct tree_ssa_name in;
695 gcc_assert (SSA_VAR_P (var));
697 ind.uid = DECL_UID (var);
700 loc = htab_find_slot_with_hash (DEFAULT_DEFS (cfun), &in,
701 DECL_UID (var), INSERT);
703 htab_remove_elt (DEFAULT_DEFS (cfun), *loc);
706 gcc_assert (TREE_CODE (def) == SSA_NAME && SSA_NAME_VAR (def) == var);
707 loc = htab_find_slot_with_hash (DEFAULT_DEFS (cfun), &in,
708 DECL_UID (var), INSERT);
710 /* Default definition might be changed by tail call optimization. */
712 SSA_NAME_IS_DEFAULT_DEF (*(tree *) loc) = false;
715 /* Mark DEF as the default definition for VAR. */
716 SSA_NAME_IS_DEFAULT_DEF (def) = true;
719 /* Add VAR to the list of referenced variables if it isn't already there. */
722 add_referenced_var (tree var)
726 v_ann = get_var_ann (var);
727 gcc_assert (DECL_P (var));
729 /* Insert VAR into the referenced_vars has table if it isn't present. */
730 if (referenced_var_check_and_insert (var))
732 /* This is the first time we found this variable, annotate it with
733 attributes that are intrinsic to the variable. */
735 /* Tag's don't have DECL_INITIAL. */
739 /* Scan DECL_INITIAL for pointer variables as they may contain
740 address arithmetic referencing the address of other
742 Even non-constant intializers need to be walked, because
743 IPA passes might prove that their are invariant later on. */
744 if (DECL_INITIAL (var)
745 /* Initializers of external variables are not useful to the
747 && !DECL_EXTERNAL (var))
748 walk_tree (&DECL_INITIAL (var), find_vars_r, NULL, 0);
752 /* Remove VAR from the list. */
755 remove_referenced_var (tree var)
758 struct tree_decl_minimal in;
760 unsigned int uid = DECL_UID (var);
762 clear_call_clobbered (var);
763 v_ann = get_var_ann (var);
765 var->base.ann = NULL;
766 gcc_assert (DECL_P (var));
768 loc = htab_find_slot_with_hash (gimple_referenced_vars (cfun), &in, uid,
770 htab_clear_slot (gimple_referenced_vars (cfun), loc);
774 /* Return the virtual variable associated to the non-scalar variable VAR. */
777 get_virtual_var (tree var)
781 if (TREE_CODE (var) == SSA_NAME)
782 var = SSA_NAME_VAR (var);
784 while (TREE_CODE (var) == REALPART_EXPR || TREE_CODE (var) == IMAGPART_EXPR
785 || handled_component_p (var))
786 var = TREE_OPERAND (var, 0);
788 /* Treating GIMPLE registers as virtual variables makes no sense.
789 Also complain if we couldn't extract a _DECL out of the original
791 gcc_assert (SSA_VAR_P (var));
792 gcc_assert (!is_gimple_reg (var));
797 /* Mark all the naked symbols in STMT for SSA renaming.
799 NOTE: This function should only be used for brand new statements.
800 If the caller is modifying an existing statement, it should use the
801 combination push_stmt_changes/pop_stmt_changes. */
804 mark_symbols_for_renaming (tree stmt)
811 /* Mark all the operands for renaming. */
812 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_OPERANDS)
814 mark_sym_for_renaming (op);
818 /* Find all variables within the gimplified statement that were not previously
819 visible to the function and add them to the referenced variables list. */
822 find_new_referenced_vars_1 (tree *tp, int *walk_subtrees,
823 void *data ATTRIBUTE_UNUSED)
827 if (TREE_CODE (t) == VAR_DECL && !var_ann (t))
829 add_referenced_var (t);
830 mark_sym_for_renaming (t);
833 if (IS_TYPE_OR_DECL_P (t))
840 find_new_referenced_vars (tree *stmt_p)
842 walk_tree (stmt_p, find_new_referenced_vars_1, NULL, NULL);
846 /* If EXP is a handled component reference for a structure, return the
847 base variable. The access range is delimited by bit positions *POFFSET and
848 *POFFSET + *PMAX_SIZE. The access size is *PSIZE bits. If either
849 *PSIZE or *PMAX_SIZE is -1, they could not be determined. If *PSIZE
850 and *PMAX_SIZE are equal, the access is non-variable. */
853 get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
854 HOST_WIDE_INT *psize,
855 HOST_WIDE_INT *pmax_size)
857 HOST_WIDE_INT bitsize = -1;
858 HOST_WIDE_INT maxsize = -1;
859 tree size_tree = NULL_TREE;
860 HOST_WIDE_INT bit_offset = 0;
861 bool seen_variable_array_ref = false;
863 gcc_assert (!SSA_VAR_P (exp));
865 /* First get the final access size from just the outermost expression. */
866 if (TREE_CODE (exp) == COMPONENT_REF)
867 size_tree = DECL_SIZE (TREE_OPERAND (exp, 1));
868 else if (TREE_CODE (exp) == BIT_FIELD_REF)
869 size_tree = TREE_OPERAND (exp, 1);
872 enum machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
874 size_tree = TYPE_SIZE (TREE_TYPE (exp));
876 bitsize = GET_MODE_BITSIZE (mode);
878 if (size_tree != NULL_TREE)
880 if (! host_integerp (size_tree, 1))
883 bitsize = TREE_INT_CST_LOW (size_tree);
886 /* Initially, maxsize is the same as the accessed element size.
887 In the following it will only grow (or become -1). */
890 /* Compute cumulative bit-offset for nested component-refs and array-refs,
891 and find the ultimate containing object. */
894 switch (TREE_CODE (exp))
897 bit_offset += tree_low_cst (TREE_OPERAND (exp, 2), 0);
902 tree field = TREE_OPERAND (exp, 1);
903 tree this_offset = component_ref_field_offset (exp);
905 if (this_offset && TREE_CODE (this_offset) == INTEGER_CST)
907 HOST_WIDE_INT hthis_offset = tree_low_cst (this_offset, 0);
909 hthis_offset *= BITS_PER_UNIT;
910 bit_offset += hthis_offset;
911 bit_offset += tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 0);
915 tree csize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
916 /* We need to adjust maxsize to the whole structure bitsize.
917 But we can subtract any constant offset seen sofar,
918 because that would get us out of the structure otherwise. */
919 if (maxsize != -1 && csize && host_integerp (csize, 1))
920 maxsize = TREE_INT_CST_LOW (csize) - bit_offset;
928 case ARRAY_RANGE_REF:
930 tree index = TREE_OPERAND (exp, 1);
931 tree low_bound = array_ref_low_bound (exp);
932 tree unit_size = array_ref_element_size (exp);
934 /* If the resulting bit-offset is constant, track it. */
935 if (host_integerp (index, 0)
936 && host_integerp (low_bound, 0)
937 && host_integerp (unit_size, 1))
939 HOST_WIDE_INT hindex = tree_low_cst (index, 0);
941 hindex -= tree_low_cst (low_bound, 0);
942 hindex *= tree_low_cst (unit_size, 1);
943 hindex *= BITS_PER_UNIT;
944 bit_offset += hindex;
946 /* An array ref with a constant index up in the structure
947 hierarchy will constrain the size of any variable array ref
948 lower in the access hierarchy. */
949 seen_variable_array_ref = false;
953 tree asize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
954 /* We need to adjust maxsize to the whole array bitsize.
955 But we can subtract any constant offset seen sofar,
956 because that would get us outside of the array otherwise. */
957 if (maxsize != -1 && asize && host_integerp (asize, 1))
958 maxsize = TREE_INT_CST_LOW (asize) - bit_offset;
962 /* Remember that we have seen an array ref with a variable
964 seen_variable_array_ref = true;
973 bit_offset += bitsize;
976 case VIEW_CONVERT_EXPR:
977 /* ??? We probably should give up here and bail out. */
984 exp = TREE_OPERAND (exp, 0);
988 /* We need to deal with variable arrays ending structures such as
989 struct { int length; int a[1]; } x; x.a[d]
990 struct { struct { int a; int b; } a[1]; } x; x.a[d].a
991 struct { struct { int a[1]; } a[1]; } x; x.a[0][d], x.a[d][0]
992 where we do not know maxsize for variable index accesses to
993 the array. The simplest way to conservatively deal with this
994 is to punt in the case that offset + maxsize reaches the
995 base type boundary. */
996 if (seen_variable_array_ref
998 && host_integerp (TYPE_SIZE (TREE_TYPE (exp)), 1)
999 && bit_offset + maxsize
1000 == (signed)TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (exp))))
1003 /* ??? Due to negative offsets in ARRAY_REF we can end up with
1004 negative bit_offset here. We might want to store a zero offset
1006 *poffset = bit_offset;
1008 *pmax_size = maxsize;
1014 /* Return memory reference statistics for variable VAR in function FN.
1015 This is computed by alias analysis, but it is not kept
1016 incrementally up-to-date. So, these stats are only accurate if
1017 pass_may_alias has been run recently. If no alias information
1018 exists, this function returns NULL. */
1021 mem_sym_stats (struct function *fn, tree var)
1024 struct pointer_map_t *stats_map = gimple_mem_ref_stats (fn)->mem_sym_stats;
1026 if (stats_map == NULL)
1029 slot = pointer_map_contains (stats_map, var);
1033 return (mem_sym_stats_t) *slot;