1 /* Data flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004 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, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #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-alias-common.h"
46 #include "tree-pass.h"
50 /* Build and maintain data flow information for trees. */
52 /* Counters used to display DFA and SSA statistics. */
68 /* State information for find_vars_r. */
71 /* Hash table used to avoid adding the same variable more than once. */
76 /* Local functions. */
77 static void collect_dfa_stats (struct dfa_stats_d *);
78 static tree collect_dfa_stats_r (tree *, int *, void *);
79 static void add_immediate_use (tree, tree);
80 static tree find_vars_r (tree *, int *, void *);
81 static void add_referenced_var (tree, struct walk_state *);
82 static void compute_immediate_uses_for_phi (tree, bool (*)(tree));
83 static void compute_immediate_uses_for_stmt (tree, int, bool (*)(tree));
84 static void find_hidden_use_vars (tree);
85 static tree find_hidden_use_vars_r (tree *, int *, void *);
88 /* Global declarations. */
90 /* Array of all variables referenced in the function. */
91 varray_type referenced_vars;
94 /*---------------------------------------------------------------------------
95 Dataflow analysis (DFA) routines
96 ---------------------------------------------------------------------------*/
97 /* Find all the variables referenced in the function. This function
98 builds the global arrays REFERENCED_VARS and CALL_CLOBBERED_VARS.
100 Note that this function does not look for statement operands, it simply
101 determines what variables are referenced in the program and detects
102 various attributes for each variable used by alias analysis and the
106 find_referenced_vars (void)
110 block_stmt_iterator si;
111 struct walk_state walk_state;
114 /* This is the very first pass in preparation for building the SSA
115 form of the function, so initialize internal data structures now. */
118 /* Walk the lexical blocks in the function looking for variables that may
119 have been used to declare VLAs and for nested functions. Both
120 constructs create hidden uses of variables.
122 Note that at this point we may have multiple blocks hung off
123 DECL_INITIAL chained through the BLOCK_CHAIN field due to
124 how inlining works. Egad. */
125 block = DECL_INITIAL (current_function_decl);
128 find_hidden_use_vars (block);
129 block = BLOCK_CHAIN (block);
132 vars_found = htab_create (50, htab_hash_pointer, htab_eq_pointer, NULL);
133 memset (&walk_state, 0, sizeof (walk_state));
134 walk_state.vars_found = vars_found;
137 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
139 tree *stmt_p = bsi_stmt_ptr (si);
140 walk_tree (stmt_p, find_vars_r, &walk_state, NULL);
143 htab_delete (vars_found);
146 struct tree_opt_pass pass_referenced_vars =
150 find_referenced_vars, /* execute */
153 0, /* static_pass_number */
155 PROP_gimple_leh | PROP_cfg, /* properties_required */
156 PROP_referenced_vars, /* properties_provided */
157 0, /* properties_destroyed */
158 0, /* todo_flags_start */
159 0, /* todo_flags_finish */
163 /* Compute immediate uses.
165 CALC_FOR is an optional function pointer which indicates whether
166 immediate uses information should be calculated for a given SSA
167 variable. If NULL, then information is computed for all
170 FLAGS is one of {TDFA_USE_OPS, TDFA_USE_VOPS}. It is used by
171 compute_immediate_uses_for_stmt to determine whether to look at
172 virtual and/or real operands while computing def-use chains. */
175 compute_immediate_uses (int flags, bool (*calc_for)(tree))
178 block_stmt_iterator si;
184 for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
185 compute_immediate_uses_for_phi (phi, calc_for);
187 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
189 tree stmt = bsi_stmt (si);
190 get_stmt_operands (stmt);
191 compute_immediate_uses_for_stmt (stmt, flags, calc_for);
197 /* Invalidates dataflow information for a statement STMT. */
200 free_df_for_stmt (tree stmt)
202 stmt_ann_t ann = stmt_ann (stmt);
206 /* If we have a varray of immediate uses, then go ahead and release
208 if (ann->df->immediate_uses)
209 ggc_free (ann->df->immediate_uses);
211 /* Similarly for the main dataflow structure. */
218 /* Invalidate dataflow information for the whole function. */
224 block_stmt_iterator si;
230 for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
231 free_df_for_stmt (phi);
233 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
235 tree stmt = bsi_stmt (si);
236 free_df_for_stmt (stmt);
242 /* Helper for compute_immediate_uses. Check all the USE and/or VUSE
243 operands in phi node PHI and add a def-use edge between their
244 defining statement and PHI. CALC_FOR is as in
245 compute_immediate_uses.
247 PHI nodes are easy, we only need to look at their arguments. */
250 compute_immediate_uses_for_phi (tree phi, bool (*calc_for)(tree))
254 #ifdef ENABLE_CHECKING
255 if (TREE_CODE (phi) != PHI_NODE)
259 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
261 tree arg = PHI_ARG_DEF (phi, i);
263 if (TREE_CODE (arg) == SSA_NAME && (!calc_for || calc_for (arg)))
265 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (PHI_ARG_DEF (phi, i));
266 if (!IS_EMPTY_STMT (imm_rdef_stmt))
267 add_immediate_use (imm_rdef_stmt, phi);
273 /* Another helper for compute_immediate_uses. Depending on the value
274 of FLAGS, check all the USE and/or VUSE operands in STMT and add a
275 def-use edge between their defining statement and STMT. CALC_FOR
276 is as in compute_immediate_uses. */
279 compute_immediate_uses_for_stmt (tree stmt, int flags, bool (*calc_for)(tree))
284 v_may_def_optype v_may_defs;
287 #ifdef ENABLE_CHECKING
288 /* PHI nodes are handled elsewhere. */
289 if (TREE_CODE (stmt) == PHI_NODE)
293 /* Look at USE_OPS or VUSE_OPS according to FLAGS. */
294 ann = stmt_ann (stmt);
295 if (flags & TDFA_USE_OPS)
297 uses = USE_OPS (ann);
298 for (i = 0; i < NUM_USES (uses); i++)
300 tree use = USE_OP (uses, i);
301 tree imm_stmt = SSA_NAME_DEF_STMT (use);
302 if (!IS_EMPTY_STMT (imm_stmt) && (!calc_for || calc_for (use)))
303 add_immediate_use (imm_stmt, stmt);
307 if (flags & TDFA_USE_VOPS)
309 vuses = VUSE_OPS (ann);
310 for (i = 0; i < NUM_VUSES (vuses); i++)
312 tree vuse = VUSE_OP (vuses, i);
313 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (vuse);
314 if (!IS_EMPTY_STMT (imm_rdef_stmt) && (!calc_for || calc_for (vuse)))
315 add_immediate_use (imm_rdef_stmt, stmt);
318 v_may_defs = V_MAY_DEF_OPS (ann);
319 for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
321 tree vuse = V_MAY_DEF_OP (v_may_defs, i);
322 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (vuse);
323 if (!IS_EMPTY_STMT (imm_rdef_stmt) && (!calc_for || calc_for (vuse)))
324 add_immediate_use (imm_rdef_stmt, stmt);
330 /* Add statement USE_STMT to the list of statements that use definitions
334 add_immediate_use (tree stmt, tree use_stmt)
336 stmt_ann_t ann = get_stmt_ann (stmt);
337 struct dataflow_d *df;
342 df = ann->df = ggc_alloc (sizeof (struct dataflow_d));
343 memset ((void *) df, 0, sizeof (struct dataflow_d));
344 df->uses[0] = use_stmt;
350 df->uses[1] = use_stmt;
354 if (ann->df->immediate_uses == NULL)
355 VARRAY_TREE_INIT (ann->df->immediate_uses, 4, "immediate_uses");
357 VARRAY_PUSH_TREE (ann->df->immediate_uses, use_stmt);
361 /* If the immediate use of USE points to OLD, then redirect it to NEW. */
364 redirect_immediate_use (tree use, tree old, tree new)
366 tree imm_stmt = SSA_NAME_DEF_STMT (use);
367 struct dataflow_d *df = get_stmt_ann (imm_stmt)->df;
368 unsigned int num_uses = num_immediate_uses (df);
371 for (i = 0; i < num_uses; i++)
373 if (immediate_use (df, i) == old)
375 if (i == 0 || i == 1)
378 VARRAY_TREE (df->immediate_uses, i - 2) = new;
384 /* Redirect all immediate uses for operands in OLD so that they point
385 to NEW. This routine should have no knowledge of how immediate
389 redirect_immediate_uses (tree old, tree new)
391 stmt_ann_t ann = get_stmt_ann (old);
392 use_optype uses = USE_OPS (ann);
393 vuse_optype vuses = VUSE_OPS (ann);
394 v_may_def_optype v_may_defs = V_MAY_DEF_OPS (ann);
397 /* Look at USE_OPS or VUSE_OPS according to FLAGS. */
398 for (i = 0; i < NUM_USES (uses); i++)
399 redirect_immediate_use (USE_OP (uses, i), old, new);
401 for (i = 0; i < NUM_VUSES (vuses); i++)
402 redirect_immediate_use (VUSE_OP (vuses, i), old, new);
404 for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
405 redirect_immediate_use (V_MAY_DEF_OP (v_may_defs, i), old, new);
409 /*---------------------------------------------------------------------------
411 ---------------------------------------------------------------------------*/
412 /* Create a new annotation for a _DECL node T. */
415 create_var_ann (tree t)
419 #if defined ENABLE_CHECKING
423 && t->common.ann->common.type != VAR_ANN))
427 ann = ggc_alloc (sizeof (*ann));
428 memset ((void *) ann, 0, sizeof (*ann));
430 ann->common.type = VAR_ANN;
432 t->common.ann = (tree_ann) ann;
438 /* Create a new annotation for a statement node T. */
441 create_stmt_ann (tree t)
445 #if defined ENABLE_CHECKING
446 if ((!is_gimple_stmt (t) && !is_essa_node (t))
448 && t->common.ann->common.type != STMT_ANN))
452 ann = ggc_alloc (sizeof (*ann));
453 memset ((void *) ann, 0, sizeof (*ann));
455 ann->common.type = STMT_ANN;
457 /* Since we just created the annotation, mark the statement modified. */
458 ann->modified = true;
460 t->common.ann = (tree_ann) ann;
466 /* Build a temporary. Make sure and register it to be renamed. */
469 make_rename_temp (tree type, const char *prefix)
471 tree t = create_tmp_var (type, prefix);
472 add_referenced_tmp_var (t);
473 bitmap_set_bit (vars_to_rename, var_ann (t)->uid);
479 /*---------------------------------------------------------------------------
481 ---------------------------------------------------------------------------*/
482 /* Dump the list of all the referenced variables in the current function to
486 dump_referenced_vars (FILE *file)
490 fprintf (file, "\nReferenced variables in %s: %u\n\n",
491 get_name (current_function_decl), (unsigned) num_referenced_vars);
493 for (i = 0; i < num_referenced_vars; i++)
495 tree var = referenced_var (i);
496 fprintf (file, "Variable: ");
497 dump_variable (file, var);
498 fprintf (file, "\n");
503 /* Dump the list of all the referenced variables to stderr. */
506 debug_referenced_vars (void)
508 dump_referenced_vars (stderr);
512 /* Dump variable VAR and its may-aliases to FILE. */
515 dump_variable (FILE *file, tree var)
519 if (var == NULL_TREE)
521 fprintf (file, "<nil>");
525 print_generic_expr (file, var, dump_flags);
527 if (TREE_CODE (var) == SSA_NAME)
528 var = SSA_NAME_VAR (var);
532 fprintf (file, ", UID %u", (unsigned) ann->uid);
534 if (ann->has_hidden_use)
535 fprintf (file, ", has hidden uses");
537 if (ann->type_mem_tag)
539 fprintf (file, ", type memory tag: ");
540 print_generic_expr (file, ann->type_mem_tag, dump_flags);
543 if (ann->is_alias_tag)
544 fprintf (file, ", is an alias tag");
546 if (needs_to_live_in_memory (var))
547 fprintf (file, ", is %s", TREE_STATIC (var) ? "static" : "global");
549 if (is_call_clobbered (var))
550 fprintf (file, ", call clobbered");
552 if (ann->default_def)
554 fprintf (file, ", default def: ");
555 print_generic_expr (file, ann->default_def, dump_flags);
558 if (ann->may_aliases)
560 fprintf (file, ", may aliases: ");
561 dump_may_aliases_for (file, var);
564 fprintf (file, "\n");
568 /* Dump variable VAR and its may-aliases to stderr. */
571 debug_variable (tree var)
573 dump_variable (stderr, var);
577 /* Dump def-use edges on FILE. */
580 dump_immediate_uses (FILE *file)
583 block_stmt_iterator si;
585 = lang_hooks.decl_printable_name (current_function_decl, 2);
587 fprintf (file, "\nDef-use edges for function %s\n", funcname);
593 for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
594 dump_immediate_uses_for (file, phi);
596 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
597 dump_immediate_uses_for (file, bsi_stmt (si));
600 fprintf (file, "\n");
604 /* Dump def-use edges on stderr. */
607 debug_immediate_uses (void)
609 dump_immediate_uses (stderr);
613 /* Dump all immediate uses for STMT on FILE. */
616 dump_immediate_uses_for (FILE *file, tree stmt)
618 dataflow_t df = get_immediate_uses (stmt);
619 int num_imm_uses = num_immediate_uses (df);
621 if (num_imm_uses > 0)
625 fprintf (file, "-> ");
626 print_generic_stmt (file, stmt, TDF_SLIM);
627 fprintf (file, "\n");
629 for (i = 0; i < num_imm_uses; i++)
631 fprintf (file, "\t");
632 print_generic_stmt (file, immediate_use (df, i), TDF_SLIM);
633 fprintf (file, "\n");
636 fprintf (file, "\n");
641 /* Dump immediate uses for STMT on stderr. */
644 debug_immediate_uses_for (tree stmt)
646 dump_immediate_uses_for (stderr, stmt);
650 /* Dump various DFA statistics to FILE. */
653 dump_dfa_stats (FILE *file)
655 struct dfa_stats_d dfa_stats;
657 unsigned long size, total = 0;
658 const char * const fmt_str = "%-30s%-13s%12s\n";
659 const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
660 const char * const fmt_str_3 = "%-43s%11lu%c\n";
662 = lang_hooks.decl_printable_name (current_function_decl, 2);
664 collect_dfa_stats (&dfa_stats);
666 fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
668 fprintf (file, "---------------------------------------------------------\n");
669 fprintf (file, fmt_str, "", " Number of ", "Memory");
670 fprintf (file, fmt_str, "", " instances ", "used ");
671 fprintf (file, "---------------------------------------------------------\n");
673 size = num_referenced_vars * sizeof (tree);
675 fprintf (file, fmt_str_1, "Referenced variables", num_referenced_vars,
676 SCALE (size), LABEL (size));
678 size = dfa_stats.num_stmt_anns * sizeof (struct stmt_ann_d);
680 fprintf (file, fmt_str_1, "Statements annotated", dfa_stats.num_stmt_anns,
681 SCALE (size), LABEL (size));
683 size = dfa_stats.num_var_anns * sizeof (struct var_ann_d);
685 fprintf (file, fmt_str_1, "Variables annotated", dfa_stats.num_var_anns,
686 SCALE (size), LABEL (size));
688 size = dfa_stats.num_uses * sizeof (tree *);
690 fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
691 SCALE (size), LABEL (size));
693 size = dfa_stats.num_defs * sizeof (tree *);
695 fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
696 SCALE (size), LABEL (size));
698 size = dfa_stats.num_vuses * sizeof (tree *);
700 fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
701 SCALE (size), LABEL (size));
703 size = dfa_stats.num_v_may_defs * sizeof (tree *);
705 fprintf (file, fmt_str_1, "V_MAY_DEF operands", dfa_stats.num_v_may_defs,
706 SCALE (size), LABEL (size));
708 size = dfa_stats.num_v_must_defs * sizeof (tree *);
710 fprintf (file, fmt_str_1, "V_MUST_DEF operands", dfa_stats.num_v_must_defs,
711 SCALE (size), LABEL (size));
713 size = dfa_stats.num_phis * sizeof (struct tree_phi_node);
715 fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
716 SCALE (size), LABEL (size));
718 size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
720 fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
721 SCALE (size), LABEL (size));
723 fprintf (file, "---------------------------------------------------------\n");
724 fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
726 fprintf (file, "---------------------------------------------------------\n");
727 fprintf (file, "\n");
729 if (dfa_stats.num_phis)
730 fprintf (file, "Average number of arguments per PHI node: %.1f (max: %d)\n",
731 (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
732 dfa_stats.max_num_phi_args);
734 fprintf (file, "\n");
738 /* Dump DFA statistics on stderr. */
741 debug_dfa_stats (void)
743 dump_dfa_stats (stderr);
747 /* Collect DFA statistics and store them in the structure pointed by
751 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p)
755 block_stmt_iterator i;
757 if (dfa_stats_p == NULL)
760 memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d));
762 /* Walk all the trees in the function counting references. Start at
763 basic block 0, but don't stop at block boundaries. */
764 htab = htab_create (30, htab_hash_pointer, htab_eq_pointer, NULL);
766 for (i = bsi_start (BASIC_BLOCK (0)); !bsi_end_p (i); bsi_next (&i))
767 walk_tree (bsi_stmt_ptr (i), collect_dfa_stats_r, (void *) dfa_stats_p,
775 for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
777 dfa_stats_p->num_phis++;
778 dfa_stats_p->num_phi_args += PHI_NUM_ARGS (phi);
779 if (PHI_NUM_ARGS (phi) > dfa_stats_p->max_num_phi_args)
780 dfa_stats_p->max_num_phi_args = PHI_NUM_ARGS (phi);
786 /* Callback for walk_tree to collect DFA statistics for a tree and its
790 collect_dfa_stats_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
794 struct dfa_stats_d *dfa_stats_p = (struct dfa_stats_d *)data;
798 switch (ann_type (t->common.ann))
802 stmt_ann_t ann = (stmt_ann_t) t->common.ann;
803 dfa_stats_p->num_stmt_anns++;
804 dfa_stats_p->num_defs += NUM_DEFS (DEF_OPS (ann));
805 dfa_stats_p->num_uses += NUM_USES (USE_OPS (ann));
806 dfa_stats_p->num_v_may_defs +=
807 NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann));
808 dfa_stats_p->num_vuses += NUM_VUSES (VUSE_OPS (ann));
809 dfa_stats_p->num_v_must_defs +=
810 NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann));
815 dfa_stats_p->num_var_anns++;
827 /*---------------------------------------------------------------------------
828 Miscellaneous helpers
829 ---------------------------------------------------------------------------*/
830 /* Callback for walk_tree. Used to collect variables referenced in
834 find_vars_r (tree *tp, int *walk_subtrees, void *data)
837 struct walk_state *walk_state = (struct walk_state *)data;
841 /* If T is a regular variable that the optimizers are interested
842 in, add it to the list of variables. */
843 add_referenced_var (t, walk_state);
847 || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
849 /* Type, _DECL and constant nodes have no interesting children.
859 /* Add VAR to the list of dereferenced variables.
861 WALK_STATE contains a hash table used to avoid adding the same
862 variable more than once. Note that this function assumes that
863 VAR is a valid SSA variable. If WALK_STATE is NULL, no
864 duplicate checking is done. */
867 add_referenced_var (tree var, struct walk_state *walk_state)
872 v_ann = get_var_ann (var);
875 slot = htab_find_slot (walk_state->vars_found, (void *) var, INSERT);
879 if (slot == NULL || *slot == NULL)
881 /* This is the first time we find this variable, add it to the
882 REFERENCED_VARS array and annotate it with attributes that are
883 intrinsic to the variable. */
885 *slot = (void *) var;
886 v_ann->uid = num_referenced_vars;
887 VARRAY_PUSH_TREE (referenced_vars, var);
889 /* Global and static variables are call-clobbered, always. */
890 if (needs_to_live_in_memory (var))
891 mark_call_clobbered (var);
893 /* DECL_NONLOCAL variables should not be removed, as they are needed
894 to emit nested functions. */
895 if (DECL_NONLOCAL (var))
901 /* Return the virtual variable associated to the non-scalar variable VAR. */
904 get_virtual_var (tree var)
910 if (TREE_CODE (var) == SSA_NAME)
911 var = SSA_NAME_VAR (var);
913 code = TREE_CODE (var);
915 while (code == ARRAY_REF
916 || code == COMPONENT_REF
917 || code == REALPART_EXPR
918 || code == IMAGPART_EXPR)
920 var = TREE_OPERAND (var, 0);
921 code = TREE_CODE (var);
924 #ifdef ENABLE_CHECKING
925 /* Treating GIMPLE registers as virtual variables makes no sense.
926 Also complain if we couldn't extract a _DECL out of the original
929 || is_gimple_reg (var))
937 /* Mark variables in BLOCK that have hidden uses. A hidden use can
938 occur due to VLA declarations or nested functions. */
941 find_hidden_use_vars (tree block)
945 /* Check all the arrays declared in the block for VLAs.
946 While scanning the block's variables, also see if there is
947 a nested function at this scope. */
948 for (decl = BLOCK_VARS (block); decl; decl = TREE_CHAIN (decl))
951 walk_tree (&decl, find_hidden_use_vars_r, &inside_vla, NULL);
954 /* Now repeat the search in any sub-blocks. */
955 for (sub = BLOCK_SUBBLOCKS (block); sub; sub = TREE_CHAIN (sub))
956 find_hidden_use_vars (sub);
958 /* A VLA parameter may use a variable which as set from another
959 parameter to declare the size of the VLA. We need to mark the
960 variable as having a hidden use since it is used to declare the
961 VLA parameter and that declaration is not seen by the SSA code.
963 Note get_pending_sizes clears the PENDING_SIZES chain, so we
965 tem = get_pending_sizes ();
966 put_pending_sizes (tem);
967 for (; tem; tem = TREE_CHAIN (tem))
970 walk_tree (&TREE_VALUE (tem), find_hidden_use_vars_r, &inside_vla, NULL);
975 /* Callback for walk_tree used by find_hidden_use_vars to analyze each
976 variable in a lexical block. If the variable's size has a variable
977 size, then mark all objects needed to compute the variable's size
978 as having hidden uses. */
981 find_hidden_use_vars_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
982 void *data ATTRIBUTE_UNUSED)
984 int *inside_vla = (int *) data;
986 /* We need to look for hidden uses due to VLAs in variable
987 definitions. We originally used to look for these hidden
988 uses in the variable's type, but that's unreliable if the
989 type's size contains a SAVE_EXPR for a different function
990 context than the variable is used within. */
993 && ! really_constant_p (DECL_SIZE (*tp)))
994 || (DECL_SIZE_UNIT (*tp)
995 && ! really_constant_p (DECL_SIZE_UNIT (*tp)))))
997 int save = *inside_vla;
1000 walk_tree (&DECL_SIZE (*tp), find_hidden_use_vars_r, inside_vla, NULL);
1001 walk_tree (&DECL_SIZE_UNIT (*tp), find_hidden_use_vars_r,
1005 else if (*inside_vla && SSA_VAR_P (*tp))
1006 set_has_hidden_use (*tp);
1012 /* Add a temporary variable to REFERENCED_VARS. This is similar to
1013 add_referenced_var, but is used by passes that need to add new temps to
1014 the REFERENCED_VARS array after the program has been scanned for
1015 variables. The variable will just receive a new UID and be added
1016 to the REFERENCED_VARS array without checking for duplicates. */
1019 add_referenced_tmp_var (tree var)
1021 add_referenced_var (var, NULL);
1024 /* Return true if V_MAY_DEFS_AFTER contains fewer entries than
1025 V_MAY_DEFS_BEFORE. Note that this assumes that both varrays
1026 are V_MAY_DEF operands for the same statement. */
1029 v_may_defs_disappeared_p (v_may_def_optype v_may_defs_before,
1030 v_may_def_optype v_may_defs_after)
1032 /* If there was nothing before, nothing could've disappeared. */
1033 if (v_may_defs_before == NULL)
1036 /* All/some of them gone. */
1037 if (v_may_defs_after == NULL
1038 || NUM_V_MAY_DEFS (v_may_defs_before) >
1039 NUM_V_MAY_DEFS (v_may_defs_after))
1045 /* Return true if V_MUST_DEFS_AFTER contains fewer entries than
1046 V_MUST_DEFS_BEFORE. Note that this assumes that both varrays
1047 are V_MUST_DEF operands for the same statement. */
1050 v_must_defs_disappeared_p (v_must_def_optype v_must_defs_before,
1051 v_must_def_optype v_must_defs_after)
1053 /* If there was nothing before, nothing could've disappeared. */
1054 if (v_must_defs_before == NULL)
1057 /* All/some of them gone. */
1058 if (v_must_defs_after == NULL
1059 || NUM_V_MUST_DEFS (v_must_defs_before) >
1060 NUM_V_MUST_DEFS (v_must_defs_after))
1067 /* Add all the non-SSA variables found in STMT's operands to the bitmap
1071 mark_new_vars_to_rename (tree stmt, bitmap vars_to_rename)
1075 v_may_def_optype v_may_defs;
1077 v_must_def_optype v_must_defs;
1079 bitmap vars_in_vops_to_rename;
1080 bool found_exposed_symbol = false;
1081 v_may_def_optype v_may_defs_before, v_may_defs_after;
1082 v_must_def_optype v_must_defs_before, v_must_defs_after;
1085 vars_in_vops_to_rename = BITMAP_XMALLOC ();
1087 /* Before re-scanning the statement for operands, mark the existing
1088 virtual operands to be renamed again. We do this because when new
1089 symbols are exposed, the virtual operands that were here before due to
1090 aliasing will probably be removed by the call to get_stmt_operand.
1091 Therefore, we need to flag them to be renamed beforehand.
1093 We flag them in a separate bitmap because we don't really want to
1094 rename them if there are not any newly exposed symbols in the
1095 statement operands. */
1096 ann = stmt_ann (stmt);
1097 v_may_defs_before = v_may_defs = V_MAY_DEF_OPS (ann);
1098 for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
1100 tree var = V_MAY_DEF_RESULT (v_may_defs, i);
1102 var = SSA_NAME_VAR (var);
1103 bitmap_set_bit (vars_in_vops_to_rename, var_ann (var)->uid);
1106 vuses = VUSE_OPS (ann);
1107 for (i = 0; i < NUM_VUSES (vuses); i++)
1109 tree var = VUSE_OP (vuses, i);
1111 var = SSA_NAME_VAR (var);
1112 bitmap_set_bit (vars_in_vops_to_rename, var_ann (var)->uid);
1115 v_must_defs_before = v_must_defs = V_MUST_DEF_OPS (ann);
1116 for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
1118 tree var = V_MUST_DEF_OP (v_must_defs, i);
1120 var = SSA_NAME_VAR (var);
1121 bitmap_set_bit (vars_in_vops_to_rename, var_ann (var)->uid);
1124 /* Now force an operand re-scan on the statement and mark any newly
1125 exposed variables. */
1127 get_stmt_operands (stmt);
1129 defs = DEF_OPS (ann);
1130 for (i = 0; i < NUM_DEFS (defs); i++)
1132 tree var = DEF_OP (defs, i);
1135 found_exposed_symbol = true;
1136 bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
1140 uses = USE_OPS (ann);
1141 for (i = 0; i < NUM_USES (uses); i++)
1143 tree var = USE_OP (uses, i);
1146 found_exposed_symbol = true;
1147 bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
1151 v_may_defs_after = v_may_defs = V_MAY_DEF_OPS (ann);
1152 for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
1154 tree var = V_MAY_DEF_RESULT (v_may_defs, i);
1157 found_exposed_symbol = true;
1158 bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
1162 vuses = VUSE_OPS (ann);
1163 for (i = 0; i < NUM_VUSES (vuses); i++)
1165 tree var = VUSE_OP (vuses, i);
1168 found_exposed_symbol = true;
1169 bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
1173 v_must_defs_after = v_must_defs = V_MUST_DEF_OPS (ann);
1174 for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
1176 tree var = V_MUST_DEF_OP (v_must_defs, i);
1179 found_exposed_symbol = true;
1180 bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
1184 /* If we found any newly exposed symbols, or if there are fewer VDEF
1185 operands in the statement, add the variables we had set in
1186 VARS_IN_VOPS_TO_RENAME to VARS_TO_RENAME. We need to check for
1187 vanishing VDEFs because in those cases, the names that were formerly
1188 generated by this statement are not going to be available anymore. */
1189 if (found_exposed_symbol
1190 || v_may_defs_disappeared_p (v_may_defs_before, v_may_defs_after)
1191 || v_must_defs_disappeared_p (v_must_defs_before, v_must_defs_after))
1192 bitmap_a_or_b (vars_to_rename, vars_to_rename, vars_in_vops_to_rename);
1194 BITMAP_XFREE (vars_in_vops_to_rename);