1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
3 Contributed by Daniel Berlin <dberlin@dberlin.org>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
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"
31 #include "hard-reg-set.h"
32 #include "basic-block.h"
35 #include "tree-flow.h"
36 #include "tree-inline.h"
38 #include "diagnostic.h"
44 #include "tree-pass.h"
46 #include "alloc-pool.h"
47 #include "splay-tree.h"
51 #include "pointer-set.h"
53 /* The idea behind this analyzer is to generate set constraints from the
54 program, then solve the resulting constraints in order to generate the
57 Set constraints are a way of modeling program analysis problems that
58 involve sets. They consist of an inclusion constraint language,
59 describing the variables (each variable is a set) and operations that
60 are involved on the variables, and a set of rules that derive facts
61 from these operations. To solve a system of set constraints, you derive
62 all possible facts under the rules, which gives you the correct sets
65 See "Efficient Field-sensitive pointer analysis for C" by "David
66 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
67 http://citeseer.ist.psu.edu/pearce04efficient.html
69 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
70 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
71 http://citeseer.ist.psu.edu/heintze01ultrafast.html
73 There are three types of real constraint expressions, DEREF,
74 ADDRESSOF, and SCALAR. Each constraint expression consists
75 of a constraint type, a variable, and an offset.
77 SCALAR is a constraint expression type used to represent x, whether
78 it appears on the LHS or the RHS of a statement.
79 DEREF is a constraint expression type used to represent *x, whether
80 it appears on the LHS or the RHS of a statement.
81 ADDRESSOF is a constraint expression used to represent &x, whether
82 it appears on the LHS or the RHS of a statement.
84 Each pointer variable in the program is assigned an integer id, and
85 each field of a structure variable is assigned an integer id as well.
87 Structure variables are linked to their list of fields through a "next
88 field" in each variable that points to the next field in offset
90 Each variable for a structure field has
92 1. "size", that tells the size in bits of that field.
93 2. "fullsize, that tells the size in bits of the entire structure.
94 3. "offset", that tells the offset in bits from the beginning of the
95 structure to this field.
107 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
108 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
109 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
112 In order to solve the system of set constraints, the following is
115 1. Each constraint variable x has a solution set associated with it,
118 2. Constraints are separated into direct, copy, and complex.
119 Direct constraints are ADDRESSOF constraints that require no extra
120 processing, such as P = &Q
121 Copy constraints are those of the form P = Q.
122 Complex constraints are all the constraints involving dereferences
123 and offsets (including offsetted copies).
125 3. All direct constraints of the form P = &Q are processed, such
126 that Q is added to Sol(P)
128 4. All complex constraints for a given constraint variable are stored in a
129 linked list attached to that variable's node.
131 5. A directed graph is built out of the copy constraints. Each
132 constraint variable is a node in the graph, and an edge from
133 Q to P is added for each copy constraint of the form P = Q
135 6. The graph is then walked, and solution sets are
136 propagated along the copy edges, such that an edge from Q to P
137 causes Sol(P) <- Sol(P) union Sol(Q).
139 7. As we visit each node, all complex constraints associated with
140 that node are processed by adding appropriate copy edges to the graph, or the
141 appropriate variables to the solution set.
143 8. The process of walking the graph is iterated until no solution
146 Prior to walking the graph in steps 6 and 7, We perform static
147 cycle elimination on the constraint graph, as well
148 as off-line variable substitution.
150 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
151 on and turned into anything), but isn't. You can just see what offset
152 inside the pointed-to struct it's going to access.
154 TODO: Constant bounded arrays can be handled as if they were structs of the
155 same number of elements.
157 TODO: Modeling heap and incoming pointers becomes much better if we
158 add fields to them as we discover them, which we could do.
160 TODO: We could handle unions, but to be honest, it's probably not
161 worth the pain or slowdown. */
163 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
164 htab_t heapvar_for_stmt;
166 static bool use_field_sensitive = true;
167 static int in_ipa_mode = 0;
169 /* Used for predecessor bitmaps. */
170 static bitmap_obstack predbitmap_obstack;
172 /* Used for points-to sets. */
173 static bitmap_obstack pta_obstack;
175 /* Used for oldsolution members of variables. */
176 static bitmap_obstack oldpta_obstack;
178 /* Used for per-solver-iteration bitmaps. */
179 static bitmap_obstack iteration_obstack;
181 static unsigned int create_variable_info_for (tree, const char *);
182 typedef struct constraint_graph *constraint_graph_t;
183 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
186 typedef struct constraint *constraint_t;
188 DEF_VEC_P(constraint_t);
189 DEF_VEC_ALLOC_P(constraint_t,heap);
191 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
193 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
195 static struct constraint_stats
197 unsigned int total_vars;
198 unsigned int nonpointer_vars;
199 unsigned int unified_vars_static;
200 unsigned int unified_vars_dynamic;
201 unsigned int iterations;
202 unsigned int num_edges;
203 unsigned int num_implicit_edges;
204 unsigned int points_to_sets_created;
209 /* ID of this variable */
212 /* True if this is a variable created by the constraint analysis, such as
213 heap variables and constraints we had to break up. */
214 unsigned int is_artificial_var:1;
216 /* True if this is a special variable whose solution set should not be
218 unsigned int is_special_var:1;
220 /* True for variables whose size is not known or variable. */
221 unsigned int is_unknown_size_var:1;
223 /* True for (sub-)fields that represent a whole variable. */
224 unsigned int is_full_var : 1;
226 /* True if this is a heap variable. */
227 unsigned int is_heap_var:1;
229 /* True if this field may contain pointers. */
230 unsigned int may_have_pointers : 1;
232 /* A link to the variable for the next field in this structure. */
233 struct variable_info *next;
235 /* Offset of this variable, in bits, from the base variable */
236 unsigned HOST_WIDE_INT offset;
238 /* Size of the variable, in bits. */
239 unsigned HOST_WIDE_INT size;
241 /* Full size of the base variable, in bits. */
242 unsigned HOST_WIDE_INT fullsize;
244 /* Name of this variable */
247 /* Tree that this variable is associated with. */
250 /* Points-to set for this variable. */
253 /* Old points-to set for this variable. */
256 typedef struct variable_info *varinfo_t;
258 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
259 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
260 unsigned HOST_WIDE_INT);
261 static varinfo_t lookup_vi_for_tree (tree);
263 /* Pool of variable info structures. */
264 static alloc_pool variable_info_pool;
266 DEF_VEC_P(varinfo_t);
268 DEF_VEC_ALLOC_P(varinfo_t, heap);
270 /* Table of variable info structures for constraint variables.
271 Indexed directly by variable info id. */
272 static VEC(varinfo_t,heap) *varmap;
274 /* Return the varmap element N */
276 static inline varinfo_t
277 get_varinfo (unsigned int n)
279 return VEC_index (varinfo_t, varmap, n);
282 /* Static IDs for the special variables. */
283 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
284 escaped_id = 3, nonlocal_id = 4, callused_id = 5,
285 storedanything_id = 6, integer_id = 7 };
287 /* Variable that represents the unknown pointer. */
288 static varinfo_t var_anything;
289 static tree anything_tree;
291 /* Variable that represents the NULL pointer. */
292 static varinfo_t var_nothing;
293 static tree nothing_tree;
295 /* Variable that represents read only memory. */
296 static varinfo_t var_readonly;
297 static tree readonly_tree;
299 /* Variable that represents escaped memory. */
300 static varinfo_t var_escaped;
301 static tree escaped_tree;
303 /* Variable that represents nonlocal memory. */
304 static varinfo_t var_nonlocal;
305 static tree nonlocal_tree;
307 /* Variable that represents call-used memory. */
308 static varinfo_t var_callused;
309 static tree callused_tree;
311 /* Variable that represents variables that are stored to anything. */
312 static varinfo_t var_storedanything;
313 static tree storedanything_tree;
315 /* Variable that represents integers. This is used for when people do things
317 static varinfo_t var_integer;
318 static tree integer_tree;
320 /* Lookup a heap var for FROM, and return it if we find one. */
323 heapvar_lookup (tree from)
325 struct tree_map *h, in;
328 h = (struct tree_map *) htab_find_with_hash (heapvar_for_stmt, &in,
329 htab_hash_pointer (from));
335 /* Insert a mapping FROM->TO in the heap var for statement
339 heapvar_insert (tree from, tree to)
344 h = GGC_NEW (struct tree_map);
345 h->hash = htab_hash_pointer (from);
348 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->hash, INSERT);
349 *(struct tree_map **) loc = h;
352 /* Return a new variable info structure consisting for a variable
353 named NAME, and using constraint graph node NODE. */
356 new_var_info (tree t, unsigned int id, const char *name)
358 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
363 ret->is_artificial_var = false;
364 ret->is_heap_var = false;
365 ret->is_special_var = false;
366 ret->is_unknown_size_var = false;
367 ret->is_full_var = false;
368 ret->may_have_pointers = true;
369 ret->solution = BITMAP_ALLOC (&pta_obstack);
370 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
375 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
377 /* An expression that appears in a constraint. */
379 struct constraint_expr
381 /* Constraint type. */
382 constraint_expr_type type;
384 /* Variable we are referring to in the constraint. */
387 /* Offset, in bits, of this constraint from the beginning of
388 variables it ends up referring to.
390 IOW, in a deref constraint, we would deref, get the result set,
391 then add OFFSET to each member. */
392 HOST_WIDE_INT offset;
395 /* Use 0x8000... as special unknown offset. */
396 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
398 typedef struct constraint_expr ce_s;
400 DEF_VEC_ALLOC_O(ce_s, heap);
401 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool);
402 static void get_constraint_for (tree, VEC(ce_s, heap) **);
403 static void do_deref (VEC (ce_s, heap) **);
405 /* Our set constraints are made up of two constraint expressions, one
408 As described in the introduction, our set constraints each represent an
409 operation between set valued variables.
413 struct constraint_expr lhs;
414 struct constraint_expr rhs;
417 /* List of constraints that we use to build the constraint graph from. */
419 static VEC(constraint_t,heap) *constraints;
420 static alloc_pool constraint_pool;
424 DEF_VEC_ALLOC_I(int, heap);
426 /* The constraint graph is represented as an array of bitmaps
427 containing successor nodes. */
429 struct constraint_graph
431 /* Size of this graph, which may be different than the number of
432 nodes in the variable map. */
435 /* Explicit successors of each node. */
438 /* Implicit predecessors of each node (Used for variable
440 bitmap *implicit_preds;
442 /* Explicit predecessors of each node (Used for variable substitution). */
445 /* Indirect cycle representatives, or -1 if the node has no indirect
447 int *indirect_cycles;
449 /* Representative node for a node. rep[a] == a unless the node has
453 /* Equivalence class representative for a label. This is used for
454 variable substitution. */
457 /* Pointer equivalence label for a node. All nodes with the same
458 pointer equivalence label can be unified together at some point
459 (either during constraint optimization or after the constraint
463 /* Pointer equivalence representative for a label. This is used to
464 handle nodes that are pointer equivalent but not location
465 equivalent. We can unite these once the addressof constraints
466 are transformed into initial points-to sets. */
469 /* Pointer equivalence label for each node, used during variable
471 unsigned int *pointer_label;
473 /* Location equivalence label for each node, used during location
474 equivalence finding. */
475 unsigned int *loc_label;
477 /* Pointed-by set for each node, used during location equivalence
478 finding. This is pointed-by rather than pointed-to, because it
479 is constructed using the predecessor graph. */
482 /* Points to sets for pointer equivalence. This is *not* the actual
483 points-to sets for nodes. */
486 /* Bitmap of nodes where the bit is set if the node is a direct
487 node. Used for variable substitution. */
488 sbitmap direct_nodes;
490 /* Bitmap of nodes where the bit is set if the node is address
491 taken. Used for variable substitution. */
492 bitmap address_taken;
494 /* Vector of complex constraints for each graph node. Complex
495 constraints are those involving dereferences or offsets that are
497 VEC(constraint_t,heap) **complex;
500 static constraint_graph_t graph;
502 /* During variable substitution and the offline version of indirect
503 cycle finding, we create nodes to represent dereferences and
504 address taken constraints. These represent where these start and
506 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
507 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
509 /* Return the representative node for NODE, if NODE has been unioned
511 This function performs path compression along the way to finding
512 the representative. */
515 find (unsigned int node)
517 gcc_assert (node < graph->size);
518 if (graph->rep[node] != node)
519 return graph->rep[node] = find (graph->rep[node]);
523 /* Union the TO and FROM nodes to the TO nodes.
524 Note that at some point in the future, we may want to do
525 union-by-rank, in which case we are going to have to return the
526 node we unified to. */
529 unite (unsigned int to, unsigned int from)
531 gcc_assert (to < graph->size && from < graph->size);
532 if (to != from && graph->rep[from] != to)
534 graph->rep[from] = to;
540 /* Create a new constraint consisting of LHS and RHS expressions. */
543 new_constraint (const struct constraint_expr lhs,
544 const struct constraint_expr rhs)
546 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
552 /* Print out constraint C to FILE. */
555 dump_constraint (FILE *file, constraint_t c)
557 if (c->lhs.type == ADDRESSOF)
559 else if (c->lhs.type == DEREF)
561 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
562 if (c->lhs.offset == UNKNOWN_OFFSET)
563 fprintf (file, " + UNKNOWN");
564 else if (c->lhs.offset != 0)
565 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
566 fprintf (file, " = ");
567 if (c->rhs.type == ADDRESSOF)
569 else if (c->rhs.type == DEREF)
571 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
572 if (c->rhs.offset == UNKNOWN_OFFSET)
573 fprintf (file, " + UNKNOWN");
574 else if (c->rhs.offset != 0)
575 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
576 fprintf (file, "\n");
580 void debug_constraint (constraint_t);
581 void debug_constraints (void);
582 void debug_constraint_graph (void);
583 void debug_solution_for_var (unsigned int);
584 void debug_sa_points_to_info (void);
586 /* Print out constraint C to stderr. */
589 debug_constraint (constraint_t c)
591 dump_constraint (stderr, c);
594 /* Print out all constraints to FILE */
597 dump_constraints (FILE *file)
601 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
602 dump_constraint (file, c);
605 /* Print out all constraints to stderr. */
608 debug_constraints (void)
610 dump_constraints (stderr);
613 /* Print out to FILE the edge in the constraint graph that is created by
614 constraint c. The edge may have a label, depending on the type of
615 constraint that it represents. If complex1, e.g: a = *b, then the label
616 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
617 complex with an offset, e.g: a = b + 8, then the label is "+".
618 Otherwise the edge has no label. */
621 dump_constraint_edge (FILE *file, constraint_t c)
623 if (c->rhs.type != ADDRESSOF)
625 const char *src = get_varinfo (c->rhs.var)->name;
626 const char *dst = get_varinfo (c->lhs.var)->name;
627 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
628 /* Due to preprocessing of constraints, instructions like *a = *b are
629 illegal; thus, we do not have to handle such cases. */
630 if (c->lhs.type == DEREF)
631 fprintf (file, " [ label=\"*=\" ] ;\n");
632 else if (c->rhs.type == DEREF)
633 fprintf (file, " [ label=\"=*\" ] ;\n");
636 /* We must check the case where the constraint is an offset.
637 In this case, it is treated as a complex constraint. */
638 if (c->rhs.offset != c->lhs.offset)
639 fprintf (file, " [ label=\"+\" ] ;\n");
641 fprintf (file, " ;\n");
646 /* Print the constraint graph in dot format. */
649 dump_constraint_graph (FILE *file)
651 unsigned int i=0, size;
654 /* Only print the graph if it has already been initialized: */
658 /* Print the constraints used to produce the constraint graph. The
659 constraints will be printed as comments in the dot file: */
660 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
661 dump_constraints (file);
662 fprintf (file, "*/\n");
664 /* Prints the header of the dot file: */
665 fprintf (file, "\n\n// The constraint graph in dot format:\n");
666 fprintf (file, "strict digraph {\n");
667 fprintf (file, " node [\n shape = box\n ]\n");
668 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
669 fprintf (file, "\n // List of nodes in the constraint graph:\n");
671 /* The next lines print the nodes in the graph. In order to get the
672 number of nodes in the graph, we must choose the minimum between the
673 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
674 yet been initialized, then graph->size == 0, otherwise we must only
675 read nodes that have an entry in VEC (varinfo_t, varmap). */
676 size = VEC_length (varinfo_t, varmap);
677 size = size < graph->size ? size : graph->size;
678 for (i = 0; i < size; i++)
680 const char *name = get_varinfo (graph->rep[i])->name;
681 fprintf (file, " \"%s\" ;\n", name);
684 /* Go over the list of constraints printing the edges in the constraint
686 fprintf (file, "\n // The constraint edges:\n");
687 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
689 dump_constraint_edge (file, c);
691 /* Prints the tail of the dot file. By now, only the closing bracket. */
692 fprintf (file, "}\n\n\n");
695 /* Print out the constraint graph to stderr. */
698 debug_constraint_graph (void)
700 dump_constraint_graph (stderr);
705 The solver is a simple worklist solver, that works on the following
708 sbitmap changed_nodes = all zeroes;
710 For each node that is not already collapsed:
712 set bit in changed nodes
714 while (changed_count > 0)
716 compute topological ordering for constraint graph
718 find and collapse cycles in the constraint graph (updating
719 changed if necessary)
721 for each node (n) in the graph in topological order:
724 Process each complex constraint associated with the node,
725 updating changed if necessary.
727 For each outgoing edge from n, propagate the solution from n to
728 the destination of the edge, updating changed as necessary.
732 /* Return true if two constraint expressions A and B are equal. */
735 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
737 return a.type == b.type && a.var == b.var && a.offset == b.offset;
740 /* Return true if constraint expression A is less than constraint expression
741 B. This is just arbitrary, but consistent, in order to give them an
745 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
747 if (a.type == b.type)
750 return a.offset < b.offset;
752 return a.var < b.var;
755 return a.type < b.type;
758 /* Return true if constraint A is less than constraint B. This is just
759 arbitrary, but consistent, in order to give them an ordering. */
762 constraint_less (const constraint_t a, const constraint_t b)
764 if (constraint_expr_less (a->lhs, b->lhs))
766 else if (constraint_expr_less (b->lhs, a->lhs))
769 return constraint_expr_less (a->rhs, b->rhs);
772 /* Return true if two constraints A and B are equal. */
775 constraint_equal (struct constraint a, struct constraint b)
777 return constraint_expr_equal (a.lhs, b.lhs)
778 && constraint_expr_equal (a.rhs, b.rhs);
782 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
785 constraint_vec_find (VEC(constraint_t,heap) *vec,
786 struct constraint lookfor)
794 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
795 if (place >= VEC_length (constraint_t, vec))
797 found = VEC_index (constraint_t, vec, place);
798 if (!constraint_equal (*found, lookfor))
803 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
806 constraint_set_union (VEC(constraint_t,heap) **to,
807 VEC(constraint_t,heap) **from)
812 for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++)
814 if (constraint_vec_find (*to, *c) == NULL)
816 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
818 VEC_safe_insert (constraint_t, heap, *to, place, c);
823 /* Expands the solution in SET to all sub-fields of variables included.
824 Union the expanded result into RESULT. */
827 solution_set_expand (bitmap result, bitmap set)
833 /* In a first pass record all variables we need to add all
834 sub-fields off. This avoids quadratic behavior. */
835 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
837 varinfo_t v = get_varinfo (j);
838 if (v->is_artificial_var
841 v = lookup_vi_for_tree (v->decl);
843 vars = BITMAP_ALLOC (NULL);
844 bitmap_set_bit (vars, v->id);
847 /* In the second pass now do the addition to the solution and
848 to speed up solving add it to the delta as well. */
851 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
853 varinfo_t v = get_varinfo (j);
854 for (; v != NULL; v = v->next)
855 bitmap_set_bit (result, v->id);
861 /* Take a solution set SET, add OFFSET to each member of the set, and
862 overwrite SET with the result when done. */
865 solution_set_add (bitmap set, HOST_WIDE_INT offset)
867 bitmap result = BITMAP_ALLOC (&iteration_obstack);
871 /* If the offset is unknown we have to expand the solution to
873 if (offset == UNKNOWN_OFFSET)
875 solution_set_expand (set, set);
879 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
881 varinfo_t vi = get_varinfo (i);
883 /* If this is a variable with just one field just set its bit
885 if (vi->is_artificial_var
886 || vi->is_unknown_size_var
888 bitmap_set_bit (result, i);
891 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
893 /* If the offset makes the pointer point to before the
894 variable use offset zero for the field lookup. */
896 && fieldoffset > vi->offset)
900 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
902 bitmap_set_bit (result, vi->id);
903 /* If the result is not exactly at fieldoffset include the next
904 field as well. See get_constraint_for_ptr_offset for more
906 if (vi->offset != fieldoffset
908 bitmap_set_bit (result, vi->next->id);
912 bitmap_copy (set, result);
913 BITMAP_FREE (result);
916 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
920 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
923 return bitmap_ior_into (to, from);
929 tmp = BITMAP_ALLOC (&iteration_obstack);
930 bitmap_copy (tmp, from);
931 solution_set_add (tmp, inc);
932 res = bitmap_ior_into (to, tmp);
938 /* Insert constraint C into the list of complex constraints for graph
942 insert_into_complex (constraint_graph_t graph,
943 unsigned int var, constraint_t c)
945 VEC (constraint_t, heap) *complex = graph->complex[var];
946 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
949 /* Only insert constraints that do not already exist. */
950 if (place >= VEC_length (constraint_t, complex)
951 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
952 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
956 /* Condense two variable nodes into a single variable node, by moving
957 all associated info from SRC to TO. */
960 merge_node_constraints (constraint_graph_t graph, unsigned int to,
966 gcc_assert (find (from) == to);
968 /* Move all complex constraints from src node into to node */
969 for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
971 /* In complex constraints for node src, we may have either
972 a = *src, and *src = a, or an offseted constraint which are
973 always added to the rhs node's constraints. */
975 if (c->rhs.type == DEREF)
977 else if (c->lhs.type == DEREF)
982 constraint_set_union (&graph->complex[to], &graph->complex[from]);
983 VEC_free (constraint_t, heap, graph->complex[from]);
984 graph->complex[from] = NULL;
988 /* Remove edges involving NODE from GRAPH. */
991 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
993 if (graph->succs[node])
994 BITMAP_FREE (graph->succs[node]);
997 /* Merge GRAPH nodes FROM and TO into node TO. */
1000 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1003 if (graph->indirect_cycles[from] != -1)
1005 /* If we have indirect cycles with the from node, and we have
1006 none on the to node, the to node has indirect cycles from the
1007 from node now that they are unified.
1008 If indirect cycles exist on both, unify the nodes that they
1009 are in a cycle with, since we know they are in a cycle with
1011 if (graph->indirect_cycles[to] == -1)
1012 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1015 /* Merge all the successor edges. */
1016 if (graph->succs[from])
1018 if (!graph->succs[to])
1019 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1020 bitmap_ior_into (graph->succs[to],
1021 graph->succs[from]);
1024 clear_edges_for_node (graph, from);
1028 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1029 it doesn't exist in the graph already. */
1032 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1038 if (!graph->implicit_preds[to])
1039 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1041 if (bitmap_set_bit (graph->implicit_preds[to], from))
1042 stats.num_implicit_edges++;
1045 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1046 it doesn't exist in the graph already.
1047 Return false if the edge already existed, true otherwise. */
1050 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1053 if (!graph->preds[to])
1054 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1055 bitmap_set_bit (graph->preds[to], from);
1058 /* Add a graph edge to GRAPH, going from FROM to TO if
1059 it doesn't exist in the graph already.
1060 Return false if the edge already existed, true otherwise. */
1063 add_graph_edge (constraint_graph_t graph, unsigned int to,
1074 if (!graph->succs[from])
1075 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1076 if (bitmap_set_bit (graph->succs[from], to))
1079 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1087 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1090 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1093 return (graph->succs[dest]
1094 && bitmap_bit_p (graph->succs[dest], src));
1097 /* Initialize the constraint graph structure to contain SIZE nodes. */
1100 init_graph (unsigned int size)
1104 graph = XCNEW (struct constraint_graph);
1106 graph->succs = XCNEWVEC (bitmap, graph->size);
1107 graph->indirect_cycles = XNEWVEC (int, graph->size);
1108 graph->rep = XNEWVEC (unsigned int, graph->size);
1109 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1110 graph->pe = XCNEWVEC (unsigned int, graph->size);
1111 graph->pe_rep = XNEWVEC (int, graph->size);
1113 for (j = 0; j < graph->size; j++)
1116 graph->pe_rep[j] = -1;
1117 graph->indirect_cycles[j] = -1;
1121 /* Build the constraint graph, adding only predecessor edges right now. */
1124 build_pred_graph (void)
1130 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1131 graph->preds = XCNEWVEC (bitmap, graph->size);
1132 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1133 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1134 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1135 graph->points_to = XCNEWVEC (bitmap, graph->size);
1136 graph->eq_rep = XNEWVEC (int, graph->size);
1137 graph->direct_nodes = sbitmap_alloc (graph->size);
1138 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1139 sbitmap_zero (graph->direct_nodes);
1141 for (j = 0; j < FIRST_REF_NODE; j++)
1143 if (!get_varinfo (j)->is_special_var)
1144 SET_BIT (graph->direct_nodes, j);
1147 for (j = 0; j < graph->size; j++)
1148 graph->eq_rep[j] = -1;
1150 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1151 graph->indirect_cycles[j] = -1;
1153 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1155 struct constraint_expr lhs = c->lhs;
1156 struct constraint_expr rhs = c->rhs;
1157 unsigned int lhsvar = lhs.var;
1158 unsigned int rhsvar = rhs.var;
1160 if (lhs.type == DEREF)
1163 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1164 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1166 else if (rhs.type == DEREF)
1169 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1170 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1172 RESET_BIT (graph->direct_nodes, lhsvar);
1174 else if (rhs.type == ADDRESSOF)
1179 if (graph->points_to[lhsvar] == NULL)
1180 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1181 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1183 if (graph->pointed_by[rhsvar] == NULL)
1184 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1185 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1187 /* Implicitly, *x = y */
1188 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1190 /* All related variables are no longer direct nodes. */
1191 RESET_BIT (graph->direct_nodes, rhsvar);
1192 v = get_varinfo (rhsvar);
1193 if (!v->is_full_var)
1195 v = lookup_vi_for_tree (v->decl);
1198 RESET_BIT (graph->direct_nodes, v->id);
1203 bitmap_set_bit (graph->address_taken, rhsvar);
1205 else if (lhsvar > anything_id
1206 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1209 add_pred_graph_edge (graph, lhsvar, rhsvar);
1210 /* Implicitly, *x = *y */
1211 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1212 FIRST_REF_NODE + rhsvar);
1214 else if (lhs.offset != 0 || rhs.offset != 0)
1216 if (rhs.offset != 0)
1217 RESET_BIT (graph->direct_nodes, lhs.var);
1218 else if (lhs.offset != 0)
1219 RESET_BIT (graph->direct_nodes, rhs.var);
1224 /* Build the constraint graph, adding successor edges. */
1227 build_succ_graph (void)
1232 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1234 struct constraint_expr lhs;
1235 struct constraint_expr rhs;
1236 unsigned int lhsvar;
1237 unsigned int rhsvar;
1244 lhsvar = find (lhs.var);
1245 rhsvar = find (rhs.var);
1247 if (lhs.type == DEREF)
1249 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1250 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1252 else if (rhs.type == DEREF)
1254 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1255 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1257 else if (rhs.type == ADDRESSOF)
1260 gcc_assert (find (rhs.var) == rhs.var);
1261 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1263 else if (lhsvar > anything_id
1264 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1266 add_graph_edge (graph, lhsvar, rhsvar);
1270 /* Add edges from STOREDANYTHING to all non-direct nodes. */
1271 t = find (storedanything_id);
1272 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1274 if (!TEST_BIT (graph->direct_nodes, i))
1275 add_graph_edge (graph, find (i), t);
1280 /* Changed variables on the last iteration. */
1281 static unsigned int changed_count;
1282 static sbitmap changed;
1284 DEF_VEC_I(unsigned);
1285 DEF_VEC_ALLOC_I(unsigned,heap);
1288 /* Strongly Connected Component visitation info. */
1295 unsigned int *node_mapping;
1297 VEC(unsigned,heap) *scc_stack;
1301 /* Recursive routine to find strongly connected components in GRAPH.
1302 SI is the SCC info to store the information in, and N is the id of current
1303 graph node we are processing.
1305 This is Tarjan's strongly connected component finding algorithm, as
1306 modified by Nuutila to keep only non-root nodes on the stack.
1307 The algorithm can be found in "On finding the strongly connected
1308 connected components in a directed graph" by Esko Nuutila and Eljas
1309 Soisalon-Soininen, in Information Processing Letters volume 49,
1310 number 1, pages 9-14. */
1313 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1317 unsigned int my_dfs;
1319 SET_BIT (si->visited, n);
1320 si->dfs[n] = si->current_index ++;
1321 my_dfs = si->dfs[n];
1323 /* Visit all the successors. */
1324 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1328 if (i > LAST_REF_NODE)
1332 if (TEST_BIT (si->deleted, w))
1335 if (!TEST_BIT (si->visited, w))
1336 scc_visit (graph, si, w);
1338 unsigned int t = find (w);
1339 unsigned int nnode = find (n);
1340 gcc_assert (nnode == n);
1342 if (si->dfs[t] < si->dfs[nnode])
1343 si->dfs[n] = si->dfs[t];
1347 /* See if any components have been identified. */
1348 if (si->dfs[n] == my_dfs)
1350 if (VEC_length (unsigned, si->scc_stack) > 0
1351 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1353 bitmap scc = BITMAP_ALLOC (NULL);
1354 bool have_ref_node = n >= FIRST_REF_NODE;
1355 unsigned int lowest_node;
1358 bitmap_set_bit (scc, n);
1360 while (VEC_length (unsigned, si->scc_stack) != 0
1361 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1363 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1365 bitmap_set_bit (scc, w);
1366 if (w >= FIRST_REF_NODE)
1367 have_ref_node = true;
1370 lowest_node = bitmap_first_set_bit (scc);
1371 gcc_assert (lowest_node < FIRST_REF_NODE);
1373 /* Collapse the SCC nodes into a single node, and mark the
1375 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1377 if (i < FIRST_REF_NODE)
1379 if (unite (lowest_node, i))
1380 unify_nodes (graph, lowest_node, i, false);
1384 unite (lowest_node, i);
1385 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1389 SET_BIT (si->deleted, n);
1392 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1395 /* Unify node FROM into node TO, updating the changed count if
1396 necessary when UPDATE_CHANGED is true. */
1399 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1400 bool update_changed)
1403 gcc_assert (to != from && find (to) == to);
1404 if (dump_file && (dump_flags & TDF_DETAILS))
1405 fprintf (dump_file, "Unifying %s to %s\n",
1406 get_varinfo (from)->name,
1407 get_varinfo (to)->name);
1410 stats.unified_vars_dynamic++;
1412 stats.unified_vars_static++;
1414 merge_graph_nodes (graph, to, from);
1415 merge_node_constraints (graph, to, from);
1417 /* Mark TO as changed if FROM was changed. If TO was already marked
1418 as changed, decrease the changed count. */
1420 if (update_changed && TEST_BIT (changed, from))
1422 RESET_BIT (changed, from);
1423 if (!TEST_BIT (changed, to))
1424 SET_BIT (changed, to);
1427 gcc_assert (changed_count > 0);
1431 if (get_varinfo (from)->solution)
1433 /* If the solution changes because of the merging, we need to mark
1434 the variable as changed. */
1435 if (bitmap_ior_into (get_varinfo (to)->solution,
1436 get_varinfo (from)->solution))
1438 if (update_changed && !TEST_BIT (changed, to))
1440 SET_BIT (changed, to);
1445 BITMAP_FREE (get_varinfo (from)->solution);
1446 BITMAP_FREE (get_varinfo (from)->oldsolution);
1448 if (stats.iterations > 0)
1450 BITMAP_FREE (get_varinfo (to)->oldsolution);
1451 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1454 if (valid_graph_edge (graph, to, to))
1456 if (graph->succs[to])
1457 bitmap_clear_bit (graph->succs[to], to);
1461 /* Information needed to compute the topological ordering of a graph. */
1465 /* sbitmap of visited nodes. */
1467 /* Array that stores the topological order of the graph, *in
1469 VEC(unsigned,heap) *topo_order;
1473 /* Initialize and return a topological info structure. */
1475 static struct topo_info *
1476 init_topo_info (void)
1478 size_t size = graph->size;
1479 struct topo_info *ti = XNEW (struct topo_info);
1480 ti->visited = sbitmap_alloc (size);
1481 sbitmap_zero (ti->visited);
1482 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1487 /* Free the topological sort info pointed to by TI. */
1490 free_topo_info (struct topo_info *ti)
1492 sbitmap_free (ti->visited);
1493 VEC_free (unsigned, heap, ti->topo_order);
1497 /* Visit the graph in topological order, and store the order in the
1498 topo_info structure. */
1501 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1507 SET_BIT (ti->visited, n);
1509 if (graph->succs[n])
1510 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1512 if (!TEST_BIT (ti->visited, j))
1513 topo_visit (graph, ti, j);
1516 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1519 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1520 starting solution for y. */
1523 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1526 unsigned int lhs = c->lhs.var;
1528 bitmap sol = get_varinfo (lhs)->solution;
1531 HOST_WIDE_INT roffset = c->rhs.offset;
1533 /* Our IL does not allow this. */
1534 gcc_assert (c->lhs.offset == 0);
1536 /* If the solution of Y contains anything it is good enough to transfer
1538 if (bitmap_bit_p (delta, anything_id))
1540 flag |= bitmap_set_bit (sol, anything_id);
1544 /* If we do not know at with offset the rhs is dereferenced compute
1545 the reachability set of DELTA, conservatively assuming it is
1546 dereferenced at all valid offsets. */
1547 if (roffset == UNKNOWN_OFFSET)
1549 solution_set_expand (delta, delta);
1550 /* No further offset processing is necessary. */
1554 /* For each variable j in delta (Sol(y)), add
1555 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1556 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1558 varinfo_t v = get_varinfo (j);
1559 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1563 fieldoffset = v->offset;
1564 else if (roffset != 0)
1565 v = first_vi_for_offset (v, fieldoffset);
1566 /* If the access is outside of the variable we can ignore it. */
1574 /* Adding edges from the special vars is pointless.
1575 They don't have sets that can change. */
1576 if (get_varinfo (t)->is_special_var)
1577 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1578 /* Merging the solution from ESCAPED needlessly increases
1579 the set. Use ESCAPED as representative instead. */
1580 else if (v->id == escaped_id)
1581 flag |= bitmap_set_bit (sol, escaped_id);
1582 else if (add_graph_edge (graph, lhs, t))
1583 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1585 /* If the variable is not exactly at the requested offset
1586 we have to include the next one. */
1587 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1592 fieldoffset = v->offset;
1598 /* If the LHS solution changed, mark the var as changed. */
1601 get_varinfo (lhs)->solution = sol;
1602 if (!TEST_BIT (changed, lhs))
1604 SET_BIT (changed, lhs);
1610 /* Process a constraint C that represents *(x + off) = y using DELTA
1611 as the starting solution for x. */
1614 do_ds_constraint (constraint_t c, bitmap delta)
1616 unsigned int rhs = c->rhs.var;
1617 bitmap sol = get_varinfo (rhs)->solution;
1620 HOST_WIDE_INT loff = c->lhs.offset;
1622 /* Our IL does not allow this. */
1623 gcc_assert (c->rhs.offset == 0);
1625 /* If the solution of y contains ANYTHING simply use the ANYTHING
1626 solution. This avoids needlessly increasing the points-to sets. */
1627 if (bitmap_bit_p (sol, anything_id))
1628 sol = get_varinfo (find (anything_id))->solution;
1630 /* If the solution for x contains ANYTHING we have to merge the
1631 solution of y into all pointer variables which we do via
1633 if (bitmap_bit_p (delta, anything_id))
1635 unsigned t = find (storedanything_id);
1636 if (add_graph_edge (graph, t, rhs))
1638 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1640 if (!TEST_BIT (changed, t))
1642 SET_BIT (changed, t);
1650 /* If we do not know at with offset the rhs is dereferenced compute
1651 the reachability set of DELTA, conservatively assuming it is
1652 dereferenced at all valid offsets. */
1653 if (loff == UNKNOWN_OFFSET)
1655 solution_set_expand (delta, delta);
1659 /* For each member j of delta (Sol(x)), add an edge from y to j and
1660 union Sol(y) into Sol(j) */
1661 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1663 varinfo_t v = get_varinfo (j);
1665 HOST_WIDE_INT fieldoffset = v->offset + loff;
1667 /* If v is a NONLOCAL then this is an escape point. */
1668 if (j == nonlocal_id)
1670 t = find (escaped_id);
1671 if (add_graph_edge (graph, t, rhs)
1672 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1673 && !TEST_BIT (changed, t))
1675 SET_BIT (changed, t);
1680 if (v->is_special_var)
1684 fieldoffset = v->offset;
1686 v = first_vi_for_offset (v, fieldoffset);
1687 /* If the access is outside of the variable we can ignore it. */
1693 if (v->may_have_pointers)
1696 if (add_graph_edge (graph, t, rhs)
1697 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1698 && !TEST_BIT (changed, t))
1700 SET_BIT (changed, t);
1704 /* If v is a global variable then this is an escape point. */
1705 if (is_global_var (v->decl))
1707 t = find (escaped_id);
1708 if (add_graph_edge (graph, t, rhs)
1709 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1710 && !TEST_BIT (changed, t))
1712 SET_BIT (changed, t);
1717 /* If the variable is not exactly at the requested offset
1718 we have to include the next one. */
1719 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1724 fieldoffset = v->offset;
1730 /* Handle a non-simple (simple meaning requires no iteration),
1731 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1734 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1736 if (c->lhs.type == DEREF)
1738 if (c->rhs.type == ADDRESSOF)
1745 do_ds_constraint (c, delta);
1748 else if (c->rhs.type == DEREF)
1751 if (!(get_varinfo (c->lhs.var)->is_special_var))
1752 do_sd_constraint (graph, c, delta);
1760 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1761 solution = get_varinfo (c->rhs.var)->solution;
1762 tmp = get_varinfo (c->lhs.var)->solution;
1764 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1768 get_varinfo (c->lhs.var)->solution = tmp;
1769 if (!TEST_BIT (changed, c->lhs.var))
1771 SET_BIT (changed, c->lhs.var);
1778 /* Initialize and return a new SCC info structure. */
1780 static struct scc_info *
1781 init_scc_info (size_t size)
1783 struct scc_info *si = XNEW (struct scc_info);
1786 si->current_index = 0;
1787 si->visited = sbitmap_alloc (size);
1788 sbitmap_zero (si->visited);
1789 si->deleted = sbitmap_alloc (size);
1790 sbitmap_zero (si->deleted);
1791 si->node_mapping = XNEWVEC (unsigned int, size);
1792 si->dfs = XCNEWVEC (unsigned int, size);
1794 for (i = 0; i < size; i++)
1795 si->node_mapping[i] = i;
1797 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1801 /* Free an SCC info structure pointed to by SI */
1804 free_scc_info (struct scc_info *si)
1806 sbitmap_free (si->visited);
1807 sbitmap_free (si->deleted);
1808 free (si->node_mapping);
1810 VEC_free (unsigned, heap, si->scc_stack);
1815 /* Find indirect cycles in GRAPH that occur, using strongly connected
1816 components, and note them in the indirect cycles map.
1818 This technique comes from Ben Hardekopf and Calvin Lin,
1819 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1820 Lines of Code", submitted to PLDI 2007. */
1823 find_indirect_cycles (constraint_graph_t graph)
1826 unsigned int size = graph->size;
1827 struct scc_info *si = init_scc_info (size);
1829 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1830 if (!TEST_BIT (si->visited, i) && find (i) == i)
1831 scc_visit (graph, si, i);
1836 /* Compute a topological ordering for GRAPH, and store the result in the
1837 topo_info structure TI. */
1840 compute_topo_order (constraint_graph_t graph,
1841 struct topo_info *ti)
1844 unsigned int size = graph->size;
1846 for (i = 0; i != size; ++i)
1847 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1848 topo_visit (graph, ti, i);
1851 /* Structure used to for hash value numbering of pointer equivalence
1854 typedef struct equiv_class_label
1857 unsigned int equivalence_class;
1859 } *equiv_class_label_t;
1860 typedef const struct equiv_class_label *const_equiv_class_label_t;
1862 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1864 static htab_t pointer_equiv_class_table;
1866 /* A hashtable for mapping a bitmap of labels->location equivalence
1868 static htab_t location_equiv_class_table;
1870 /* Hash function for a equiv_class_label_t */
1873 equiv_class_label_hash (const void *p)
1875 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1876 return ecl->hashcode;
1879 /* Equality function for two equiv_class_label_t's. */
1882 equiv_class_label_eq (const void *p1, const void *p2)
1884 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1885 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1886 return (eql1->hashcode == eql2->hashcode
1887 && bitmap_equal_p (eql1->labels, eql2->labels));
1890 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1894 equiv_class_lookup (htab_t table, bitmap labels)
1897 struct equiv_class_label ecl;
1899 ecl.labels = labels;
1900 ecl.hashcode = bitmap_hash (labels);
1902 slot = htab_find_slot_with_hash (table, &ecl,
1903 ecl.hashcode, NO_INSERT);
1907 return ((equiv_class_label_t) *slot)->equivalence_class;
1911 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1915 equiv_class_add (htab_t table, unsigned int equivalence_class,
1919 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1921 ecl->labels = labels;
1922 ecl->equivalence_class = equivalence_class;
1923 ecl->hashcode = bitmap_hash (labels);
1925 slot = htab_find_slot_with_hash (table, ecl,
1926 ecl->hashcode, INSERT);
1927 gcc_assert (!*slot);
1928 *slot = (void *) ecl;
1931 /* Perform offline variable substitution.
1933 This is a worst case quadratic time way of identifying variables
1934 that must have equivalent points-to sets, including those caused by
1935 static cycles, and single entry subgraphs, in the constraint graph.
1937 The technique is described in "Exploiting Pointer and Location
1938 Equivalence to Optimize Pointer Analysis. In the 14th International
1939 Static Analysis Symposium (SAS), August 2007." It is known as the
1940 "HU" algorithm, and is equivalent to value numbering the collapsed
1941 constraint graph including evaluating unions.
1943 The general method of finding equivalence classes is as follows:
1944 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1945 Initialize all non-REF nodes to be direct nodes.
1946 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1948 For each constraint containing the dereference, we also do the same
1951 We then compute SCC's in the graph and unify nodes in the same SCC,
1954 For each non-collapsed node x:
1955 Visit all unvisited explicit incoming edges.
1956 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1958 Lookup the equivalence class for pts(x).
1959 If we found one, equivalence_class(x) = found class.
1960 Otherwise, equivalence_class(x) = new class, and new_class is
1961 added to the lookup table.
1963 All direct nodes with the same equivalence class can be replaced
1964 with a single representative node.
1965 All unlabeled nodes (label == 0) are not pointers and all edges
1966 involving them can be eliminated.
1967 We perform these optimizations during rewrite_constraints
1969 In addition to pointer equivalence class finding, we also perform
1970 location equivalence class finding. This is the set of variables
1971 that always appear together in points-to sets. We use this to
1972 compress the size of the points-to sets. */
1974 /* Current maximum pointer equivalence class id. */
1975 static int pointer_equiv_class;
1977 /* Current maximum location equivalence class id. */
1978 static int location_equiv_class;
1980 /* Recursive routine to find strongly connected components in GRAPH,
1981 and label it's nodes with DFS numbers. */
1984 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1988 unsigned int my_dfs;
1990 gcc_assert (si->node_mapping[n] == n);
1991 SET_BIT (si->visited, n);
1992 si->dfs[n] = si->current_index ++;
1993 my_dfs = si->dfs[n];
1995 /* Visit all the successors. */
1996 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
1998 unsigned int w = si->node_mapping[i];
2000 if (TEST_BIT (si->deleted, w))
2003 if (!TEST_BIT (si->visited, w))
2004 condense_visit (graph, si, w);
2006 unsigned int t = si->node_mapping[w];
2007 unsigned int nnode = si->node_mapping[n];
2008 gcc_assert (nnode == n);
2010 if (si->dfs[t] < si->dfs[nnode])
2011 si->dfs[n] = si->dfs[t];
2015 /* Visit all the implicit predecessors. */
2016 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2018 unsigned int w = si->node_mapping[i];
2020 if (TEST_BIT (si->deleted, w))
2023 if (!TEST_BIT (si->visited, w))
2024 condense_visit (graph, si, w);
2026 unsigned int t = si->node_mapping[w];
2027 unsigned int nnode = si->node_mapping[n];
2028 gcc_assert (nnode == n);
2030 if (si->dfs[t] < si->dfs[nnode])
2031 si->dfs[n] = si->dfs[t];
2035 /* See if any components have been identified. */
2036 if (si->dfs[n] == my_dfs)
2038 while (VEC_length (unsigned, si->scc_stack) != 0
2039 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2041 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2042 si->node_mapping[w] = n;
2044 if (!TEST_BIT (graph->direct_nodes, w))
2045 RESET_BIT (graph->direct_nodes, n);
2047 /* Unify our nodes. */
2048 if (graph->preds[w])
2050 if (!graph->preds[n])
2051 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2052 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2054 if (graph->implicit_preds[w])
2056 if (!graph->implicit_preds[n])
2057 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2058 bitmap_ior_into (graph->implicit_preds[n],
2059 graph->implicit_preds[w]);
2061 if (graph->points_to[w])
2063 if (!graph->points_to[n])
2064 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2065 bitmap_ior_into (graph->points_to[n],
2066 graph->points_to[w]);
2069 SET_BIT (si->deleted, n);
2072 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2075 /* Label pointer equivalences. */
2078 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2082 SET_BIT (si->visited, n);
2084 if (!graph->points_to[n])
2085 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2087 /* Label and union our incoming edges's points to sets. */
2088 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2090 unsigned int w = si->node_mapping[i];
2091 if (!TEST_BIT (si->visited, w))
2092 label_visit (graph, si, w);
2094 /* Skip unused edges */
2095 if (w == n || graph->pointer_label[w] == 0)
2098 if (graph->points_to[w])
2099 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2101 /* Indirect nodes get fresh variables. */
2102 if (!TEST_BIT (graph->direct_nodes, n))
2103 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2105 if (!bitmap_empty_p (graph->points_to[n]))
2107 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2108 graph->points_to[n]);
2111 label = pointer_equiv_class++;
2112 equiv_class_add (pointer_equiv_class_table,
2113 label, graph->points_to[n]);
2115 graph->pointer_label[n] = label;
2119 /* Perform offline variable substitution, discovering equivalence
2120 classes, and eliminating non-pointer variables. */
2122 static struct scc_info *
2123 perform_var_substitution (constraint_graph_t graph)
2126 unsigned int size = graph->size;
2127 struct scc_info *si = init_scc_info (size);
2129 bitmap_obstack_initialize (&iteration_obstack);
2130 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2131 equiv_class_label_eq, free);
2132 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2133 equiv_class_label_eq, free);
2134 pointer_equiv_class = 1;
2135 location_equiv_class = 1;
2137 /* Condense the nodes, which means to find SCC's, count incoming
2138 predecessors, and unite nodes in SCC's. */
2139 for (i = 0; i < FIRST_REF_NODE; i++)
2140 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2141 condense_visit (graph, si, si->node_mapping[i]);
2143 sbitmap_zero (si->visited);
2144 /* Actually the label the nodes for pointer equivalences */
2145 for (i = 0; i < FIRST_REF_NODE; i++)
2146 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2147 label_visit (graph, si, si->node_mapping[i]);
2149 /* Calculate location equivalence labels. */
2150 for (i = 0; i < FIRST_REF_NODE; i++)
2157 if (!graph->pointed_by[i])
2159 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2161 /* Translate the pointed-by mapping for pointer equivalence
2163 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2165 bitmap_set_bit (pointed_by,
2166 graph->pointer_label[si->node_mapping[j]]);
2168 /* The original pointed_by is now dead. */
2169 BITMAP_FREE (graph->pointed_by[i]);
2171 /* Look up the location equivalence label if one exists, or make
2173 label = equiv_class_lookup (location_equiv_class_table,
2177 label = location_equiv_class++;
2178 equiv_class_add (location_equiv_class_table,
2183 if (dump_file && (dump_flags & TDF_DETAILS))
2184 fprintf (dump_file, "Found location equivalence for node %s\n",
2185 get_varinfo (i)->name);
2186 BITMAP_FREE (pointed_by);
2188 graph->loc_label[i] = label;
2192 if (dump_file && (dump_flags & TDF_DETAILS))
2193 for (i = 0; i < FIRST_REF_NODE; i++)
2195 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2197 "Equivalence classes for %s node id %d:%s are pointer: %d"
2199 direct_node ? "Direct node" : "Indirect node", i,
2200 get_varinfo (i)->name,
2201 graph->pointer_label[si->node_mapping[i]],
2202 graph->loc_label[si->node_mapping[i]]);
2205 /* Quickly eliminate our non-pointer variables. */
2207 for (i = 0; i < FIRST_REF_NODE; i++)
2209 unsigned int node = si->node_mapping[i];
2211 if (graph->pointer_label[node] == 0)
2213 if (dump_file && (dump_flags & TDF_DETAILS))
2215 "%s is a non-pointer variable, eliminating edges.\n",
2216 get_varinfo (node)->name);
2217 stats.nonpointer_vars++;
2218 clear_edges_for_node (graph, node);
2225 /* Free information that was only necessary for variable
2229 free_var_substitution_info (struct scc_info *si)
2232 free (graph->pointer_label);
2233 free (graph->loc_label);
2234 free (graph->pointed_by);
2235 free (graph->points_to);
2236 free (graph->eq_rep);
2237 sbitmap_free (graph->direct_nodes);
2238 htab_delete (pointer_equiv_class_table);
2239 htab_delete (location_equiv_class_table);
2240 bitmap_obstack_release (&iteration_obstack);
2243 /* Return an existing node that is equivalent to NODE, which has
2244 equivalence class LABEL, if one exists. Return NODE otherwise. */
2247 find_equivalent_node (constraint_graph_t graph,
2248 unsigned int node, unsigned int label)
2250 /* If the address version of this variable is unused, we can
2251 substitute it for anything else with the same label.
2252 Otherwise, we know the pointers are equivalent, but not the
2253 locations, and we can unite them later. */
2255 if (!bitmap_bit_p (graph->address_taken, node))
2257 gcc_assert (label < graph->size);
2259 if (graph->eq_rep[label] != -1)
2261 /* Unify the two variables since we know they are equivalent. */
2262 if (unite (graph->eq_rep[label], node))
2263 unify_nodes (graph, graph->eq_rep[label], node, false);
2264 return graph->eq_rep[label];
2268 graph->eq_rep[label] = node;
2269 graph->pe_rep[label] = node;
2274 gcc_assert (label < graph->size);
2275 graph->pe[node] = label;
2276 if (graph->pe_rep[label] == -1)
2277 graph->pe_rep[label] = node;
2283 /* Unite pointer equivalent but not location equivalent nodes in
2284 GRAPH. This may only be performed once variable substitution is
2288 unite_pointer_equivalences (constraint_graph_t graph)
2292 /* Go through the pointer equivalences and unite them to their
2293 representative, if they aren't already. */
2294 for (i = 0; i < FIRST_REF_NODE; i++)
2296 unsigned int label = graph->pe[i];
2299 int label_rep = graph->pe_rep[label];
2301 if (label_rep == -1)
2304 label_rep = find (label_rep);
2305 if (label_rep >= 0 && unite (label_rep, find (i)))
2306 unify_nodes (graph, label_rep, i, false);
2311 /* Move complex constraints to the GRAPH nodes they belong to. */
2314 move_complex_constraints (constraint_graph_t graph)
2319 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2323 struct constraint_expr lhs = c->lhs;
2324 struct constraint_expr rhs = c->rhs;
2326 if (lhs.type == DEREF)
2328 insert_into_complex (graph, lhs.var, c);
2330 else if (rhs.type == DEREF)
2332 if (!(get_varinfo (lhs.var)->is_special_var))
2333 insert_into_complex (graph, rhs.var, c);
2335 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2336 && (lhs.offset != 0 || rhs.offset != 0))
2338 insert_into_complex (graph, rhs.var, c);
2345 /* Optimize and rewrite complex constraints while performing
2346 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2347 result of perform_variable_substitution. */
2350 rewrite_constraints (constraint_graph_t graph,
2351 struct scc_info *si)
2357 for (j = 0; j < graph->size; j++)
2358 gcc_assert (find (j) == j);
2360 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2362 struct constraint_expr lhs = c->lhs;
2363 struct constraint_expr rhs = c->rhs;
2364 unsigned int lhsvar = find (lhs.var);
2365 unsigned int rhsvar = find (rhs.var);
2366 unsigned int lhsnode, rhsnode;
2367 unsigned int lhslabel, rhslabel;
2369 lhsnode = si->node_mapping[lhsvar];
2370 rhsnode = si->node_mapping[rhsvar];
2371 lhslabel = graph->pointer_label[lhsnode];
2372 rhslabel = graph->pointer_label[rhsnode];
2374 /* See if it is really a non-pointer variable, and if so, ignore
2378 if (dump_file && (dump_flags & TDF_DETAILS))
2381 fprintf (dump_file, "%s is a non-pointer variable,"
2382 "ignoring constraint:",
2383 get_varinfo (lhs.var)->name);
2384 dump_constraint (dump_file, c);
2386 VEC_replace (constraint_t, constraints, i, NULL);
2392 if (dump_file && (dump_flags & TDF_DETAILS))
2395 fprintf (dump_file, "%s is a non-pointer variable,"
2396 "ignoring constraint:",
2397 get_varinfo (rhs.var)->name);
2398 dump_constraint (dump_file, c);
2400 VEC_replace (constraint_t, constraints, i, NULL);
2404 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2405 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2406 c->lhs.var = lhsvar;
2407 c->rhs.var = rhsvar;
2412 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2413 part of an SCC, false otherwise. */
2416 eliminate_indirect_cycles (unsigned int node)
2418 if (graph->indirect_cycles[node] != -1
2419 && !bitmap_empty_p (get_varinfo (node)->solution))
2422 VEC(unsigned,heap) *queue = NULL;
2424 unsigned int to = find (graph->indirect_cycles[node]);
2427 /* We can't touch the solution set and call unify_nodes
2428 at the same time, because unify_nodes is going to do
2429 bitmap unions into it. */
2431 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2433 if (find (i) == i && i != to)
2436 VEC_safe_push (unsigned, heap, queue, i);
2441 VEC_iterate (unsigned, queue, queuepos, i);
2444 unify_nodes (graph, to, i, true);
2446 VEC_free (unsigned, heap, queue);
2452 /* Solve the constraint graph GRAPH using our worklist solver.
2453 This is based on the PW* family of solvers from the "Efficient Field
2454 Sensitive Pointer Analysis for C" paper.
2455 It works by iterating over all the graph nodes, processing the complex
2456 constraints and propagating the copy constraints, until everything stops
2457 changed. This corresponds to steps 6-8 in the solving list given above. */
2460 solve_graph (constraint_graph_t graph)
2462 unsigned int size = graph->size;
2467 changed = sbitmap_alloc (size);
2468 sbitmap_zero (changed);
2470 /* Mark all initial non-collapsed nodes as changed. */
2471 for (i = 0; i < size; i++)
2473 varinfo_t ivi = get_varinfo (i);
2474 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2475 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2476 || VEC_length (constraint_t, graph->complex[i]) > 0))
2478 SET_BIT (changed, i);
2483 /* Allocate a bitmap to be used to store the changed bits. */
2484 pts = BITMAP_ALLOC (&pta_obstack);
2486 while (changed_count > 0)
2489 struct topo_info *ti = init_topo_info ();
2492 bitmap_obstack_initialize (&iteration_obstack);
2494 compute_topo_order (graph, ti);
2496 while (VEC_length (unsigned, ti->topo_order) != 0)
2499 i = VEC_pop (unsigned, ti->topo_order);
2501 /* If this variable is not a representative, skip it. */
2505 /* In certain indirect cycle cases, we may merge this
2506 variable to another. */
2507 if (eliminate_indirect_cycles (i) && find (i) != i)
2510 /* If the node has changed, we need to process the
2511 complex constraints and outgoing edges again. */
2512 if (TEST_BIT (changed, i))
2517 VEC(constraint_t,heap) *complex = graph->complex[i];
2518 bool solution_empty;
2520 RESET_BIT (changed, i);
2523 /* Compute the changed set of solution bits. */
2524 bitmap_and_compl (pts, get_varinfo (i)->solution,
2525 get_varinfo (i)->oldsolution);
2527 if (bitmap_empty_p (pts))
2530 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2532 solution = get_varinfo (i)->solution;
2533 solution_empty = bitmap_empty_p (solution);
2535 /* Process the complex constraints */
2536 for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++)
2538 /* XXX: This is going to unsort the constraints in
2539 some cases, which will occasionally add duplicate
2540 constraints during unification. This does not
2541 affect correctness. */
2542 c->lhs.var = find (c->lhs.var);
2543 c->rhs.var = find (c->rhs.var);
2545 /* The only complex constraint that can change our
2546 solution to non-empty, given an empty solution,
2547 is a constraint where the lhs side is receiving
2548 some set from elsewhere. */
2549 if (!solution_empty || c->lhs.type != DEREF)
2550 do_complex_constraint (graph, c, pts);
2553 solution_empty = bitmap_empty_p (solution);
2555 if (!solution_empty)
2558 unsigned eff_escaped_id = find (escaped_id);
2560 /* Propagate solution to all successors. */
2561 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2567 unsigned int to = find (j);
2568 tmp = get_varinfo (to)->solution;
2571 /* Don't try to propagate to ourselves. */
2575 /* If we propagate from ESCAPED use ESCAPED as
2577 if (i == eff_escaped_id)
2578 flag = bitmap_set_bit (tmp, escaped_id);
2580 flag = set_union_with_increment (tmp, pts, 0);
2584 get_varinfo (to)->solution = tmp;
2585 if (!TEST_BIT (changed, to))
2587 SET_BIT (changed, to);
2595 free_topo_info (ti);
2596 bitmap_obstack_release (&iteration_obstack);
2600 sbitmap_free (changed);
2601 bitmap_obstack_release (&oldpta_obstack);
2604 /* Map from trees to variable infos. */
2605 static struct pointer_map_t *vi_for_tree;
2608 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2611 insert_vi_for_tree (tree t, varinfo_t vi)
2613 void **slot = pointer_map_insert (vi_for_tree, t);
2615 gcc_assert (*slot == NULL);
2619 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2620 exist in the map, return NULL, otherwise, return the varinfo we found. */
2623 lookup_vi_for_tree (tree t)
2625 void **slot = pointer_map_contains (vi_for_tree, t);
2629 return (varinfo_t) *slot;
2632 /* Return a printable name for DECL */
2635 alias_get_name (tree decl)
2637 const char *res = get_name (decl);
2639 int num_printed = 0;
2648 if (TREE_CODE (decl) == SSA_NAME)
2650 num_printed = asprintf (&temp, "%s_%u",
2651 alias_get_name (SSA_NAME_VAR (decl)),
2652 SSA_NAME_VERSION (decl));
2654 else if (DECL_P (decl))
2656 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2658 if (num_printed > 0)
2660 res = ggc_strdup (temp);
2666 /* Find the variable id for tree T in the map.
2667 If T doesn't exist in the map, create an entry for it and return it. */
2670 get_vi_for_tree (tree t)
2672 void **slot = pointer_map_contains (vi_for_tree, t);
2674 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2676 return (varinfo_t) *slot;
2679 /* Get a scalar constraint expression for a new temporary variable. */
2681 static struct constraint_expr
2682 new_scalar_tmp_constraint_exp (const char *name)
2684 struct constraint_expr tmp;
2685 unsigned index = VEC_length (varinfo_t, varmap);
2688 vi = new_var_info (NULL_TREE, index, name);
2692 vi->is_full_var = 1;
2693 VEC_safe_push (varinfo_t, heap, varmap, vi);
2702 /* Get a constraint expression vector from an SSA_VAR_P node.
2703 If address_p is true, the result will be taken its address of. */
2706 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2708 struct constraint_expr cexpr;
2711 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2712 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2714 /* For parameters, get at the points-to set for the actual parm
2716 if (TREE_CODE (t) == SSA_NAME
2717 && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2718 && SSA_NAME_IS_DEFAULT_DEF (t))
2720 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2724 vi = get_vi_for_tree (t);
2726 cexpr.type = SCALAR;
2728 /* If we determine the result is "anything", and we know this is readonly,
2729 say it points to readonly memory instead. */
2730 if (cexpr.var == anything_id && TREE_READONLY (t))
2733 cexpr.type = ADDRESSOF;
2734 cexpr.var = readonly_id;
2737 /* If we are not taking the address of the constraint expr, add all
2738 sub-fiels of the variable as well. */
2741 for (; vi; vi = vi->next)
2744 VEC_safe_push (ce_s, heap, *results, &cexpr);
2749 VEC_safe_push (ce_s, heap, *results, &cexpr);
2752 /* Process constraint T, performing various simplifications and then
2753 adding it to our list of overall constraints. */
2756 process_constraint (constraint_t t)
2758 struct constraint_expr rhs = t->rhs;
2759 struct constraint_expr lhs = t->lhs;
2761 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2762 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2764 /* If we didn't get any useful constraint from the lhs we get
2765 &ANYTHING as fallback from get_constraint_for. Deal with
2766 it here by turning it into *ANYTHING. */
2767 if (lhs.type == ADDRESSOF
2768 && lhs.var == anything_id)
2771 /* ADDRESSOF on the lhs is invalid. */
2772 gcc_assert (lhs.type != ADDRESSOF);
2774 /* This can happen in our IR with things like n->a = *p */
2775 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2777 /* Split into tmp = *rhs, *lhs = tmp */
2778 struct constraint_expr tmplhs;
2779 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2780 process_constraint (new_constraint (tmplhs, rhs));
2781 process_constraint (new_constraint (lhs, tmplhs));
2783 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2785 /* Split into tmp = &rhs, *lhs = tmp */
2786 struct constraint_expr tmplhs;
2787 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2788 process_constraint (new_constraint (tmplhs, rhs));
2789 process_constraint (new_constraint (lhs, tmplhs));
2793 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2794 VEC_safe_push (constraint_t, heap, constraints, t);
2798 /* Return true if T is a type that could contain pointers. */
2801 type_could_have_pointers (tree type)
2803 if (POINTER_TYPE_P (type))
2806 if (TREE_CODE (type) == ARRAY_TYPE)
2807 return type_could_have_pointers (TREE_TYPE (type));
2809 return AGGREGATE_TYPE_P (type);
2812 /* Return true if T is a variable of a type that could contain
2816 could_have_pointers (tree t)
2818 return type_could_have_pointers (TREE_TYPE (t));
2821 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2824 static HOST_WIDE_INT
2825 bitpos_of_field (const tree fdecl)
2828 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2829 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2832 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2833 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2837 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2838 resulting constraint expressions in *RESULTS. */
2841 get_constraint_for_ptr_offset (tree ptr, tree offset,
2842 VEC (ce_s, heap) **results)
2844 struct constraint_expr *c;
2846 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2848 /* If we do not do field-sensitive PTA adding offsets to pointers
2849 does not change the points-to solution. */
2850 if (!use_field_sensitive)
2852 get_constraint_for (ptr, results);
2856 /* If the offset is not a non-negative integer constant that fits
2857 in a HOST_WIDE_INT, we have to fall back to a conservative
2858 solution which includes all sub-fields of all pointed-to
2859 variables of ptr. */
2860 if (offset == NULL_TREE
2861 || !host_integerp (offset, 0))
2862 rhsoffset = UNKNOWN_OFFSET;
2865 /* Make sure the bit-offset also fits. */
2866 rhsunitoffset = TREE_INT_CST_LOW (offset);
2867 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2868 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2869 rhsoffset = UNKNOWN_OFFSET;
2872 get_constraint_for (ptr, results);
2876 /* As we are eventually appending to the solution do not use
2877 VEC_iterate here. */
2878 n = VEC_length (ce_s, *results);
2879 for (j = 0; j < n; j++)
2882 c = VEC_index (ce_s, *results, j);
2883 curr = get_varinfo (c->var);
2885 if (c->type == ADDRESSOF
2886 /* If this varinfo represents a full variable just use it. */
2887 && curr->is_full_var)
2889 else if (c->type == ADDRESSOF
2890 /* If we do not know the offset add all subfields. */
2891 && rhsoffset == UNKNOWN_OFFSET)
2893 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2896 struct constraint_expr c2;
2898 c2.type = ADDRESSOF;
2900 if (c2.var != c->var)
2901 VEC_safe_push (ce_s, heap, *results, &c2);
2906 else if (c->type == ADDRESSOF)
2909 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2911 /* Search the sub-field which overlaps with the
2912 pointed-to offset. If the result is outside of the variable
2913 we have to provide a conservative result, as the variable is
2914 still reachable from the resulting pointer (even though it
2915 technically cannot point to anything). The last and first
2916 sub-fields are such conservative results.
2917 ??? If we always had a sub-field for &object + 1 then
2918 we could represent this in a more precise way. */
2920 && curr->offset < offset)
2922 temp = first_or_preceding_vi_for_offset (curr, offset);
2924 /* If the found variable is not exactly at the pointed to
2925 result, we have to include the next variable in the
2926 solution as well. Otherwise two increments by offset / 2
2927 do not result in the same or a conservative superset
2929 if (temp->offset != offset
2930 && temp->next != NULL)
2932 struct constraint_expr c2;
2933 c2.var = temp->next->id;
2934 c2.type = ADDRESSOF;
2936 VEC_safe_push (ce_s, heap, *results, &c2);
2942 c->offset = rhsoffset;
2947 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2948 If address_p is true the result will be taken its address of. */
2951 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2955 HOST_WIDE_INT bitsize = -1;
2956 HOST_WIDE_INT bitmaxsize = -1;
2957 HOST_WIDE_INT bitpos;
2959 struct constraint_expr *result;
2961 /* Some people like to do cute things like take the address of
2964 while (!SSA_VAR_P (forzero) && !CONSTANT_CLASS_P (forzero))
2965 forzero = TREE_OPERAND (forzero, 0);
2967 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
2969 struct constraint_expr temp;
2972 temp.var = integer_id;
2974 VEC_safe_push (ce_s, heap, *results, &temp);
2978 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
2980 /* Pretend to take the address of the base, we'll take care of
2981 adding the required subset of sub-fields below. */
2982 get_constraint_for_1 (t, results, true);
2983 gcc_assert (VEC_length (ce_s, *results) == 1);
2984 result = VEC_last (ce_s, *results);
2986 if (result->type == SCALAR
2987 && get_varinfo (result->var)->is_full_var)
2988 /* For single-field vars do not bother about the offset. */
2990 else if (result->type == SCALAR)
2992 /* In languages like C, you can access one past the end of an
2993 array. You aren't allowed to dereference it, so we can
2994 ignore this constraint. When we handle pointer subtraction,
2995 we may have to do something cute here. */
2997 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3000 /* It's also not true that the constraint will actually start at the
3001 right offset, it may start in some padding. We only care about
3002 setting the constraint to the first actual field it touches, so
3004 struct constraint_expr cexpr = *result;
3006 VEC_pop (ce_s, *results);
3008 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3010 if (ranges_overlap_p (curr->offset, curr->size,
3011 bitpos, bitmaxsize))
3013 cexpr.var = curr->id;
3014 VEC_safe_push (ce_s, heap, *results, &cexpr);
3019 /* If we are going to take the address of this field then
3020 to be able to compute reachability correctly add at least
3021 the last field of the variable. */
3023 && VEC_length (ce_s, *results) == 0)
3025 curr = get_varinfo (cexpr.var);
3026 while (curr->next != NULL)
3028 cexpr.var = curr->id;
3029 VEC_safe_push (ce_s, heap, *results, &cexpr);
3032 /* Assert that we found *some* field there. The user couldn't be
3033 accessing *only* padding. */
3034 /* Still the user could access one past the end of an array
3035 embedded in a struct resulting in accessing *only* padding. */
3036 gcc_assert (VEC_length (ce_s, *results) >= 1
3037 || ref_contains_array_ref (orig_t));
3039 else if (bitmaxsize == 0)
3041 if (dump_file && (dump_flags & TDF_DETAILS))
3042 fprintf (dump_file, "Access to zero-sized part of variable,"
3046 if (dump_file && (dump_flags & TDF_DETAILS))
3047 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3049 else if (result->type == DEREF)
3051 /* If we do not know exactly where the access goes say so. Note
3052 that only for non-structure accesses we know that we access
3053 at most one subfiled of any variable. */
3055 || bitsize != bitmaxsize
3056 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3057 result->offset = UNKNOWN_OFFSET;
3059 result->offset = bitpos;
3061 else if (result->type == ADDRESSOF)
3063 /* We can end up here for component references on a
3064 VIEW_CONVERT_EXPR <>(&foobar). */
3065 result->type = SCALAR;
3066 result->var = anything_id;
3074 /* Dereference the constraint expression CONS, and return the result.
3075 DEREF (ADDRESSOF) = SCALAR
3076 DEREF (SCALAR) = DEREF
3077 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3078 This is needed so that we can handle dereferencing DEREF constraints. */
3081 do_deref (VEC (ce_s, heap) **constraints)
3083 struct constraint_expr *c;
3086 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3088 if (c->type == SCALAR)
3090 else if (c->type == ADDRESSOF)
3092 else if (c->type == DEREF)
3094 struct constraint_expr tmplhs;
3095 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3096 process_constraint (new_constraint (tmplhs, *c));
3097 c->var = tmplhs.var;
3104 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3106 /* Given a tree T, return the constraint expression for taking the
3110 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3112 struct constraint_expr *c;
3115 get_constraint_for_1 (t, results, true);
3117 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3119 if (c->type == DEREF)
3122 c->type = ADDRESSOF;
3126 /* Given a tree T, return the constraint expression for it. */
3129 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3131 struct constraint_expr temp;
3133 /* x = integer is all glommed to a single variable, which doesn't
3134 point to anything by itself. That is, of course, unless it is an
3135 integer constant being treated as a pointer, in which case, we
3136 will return that this is really the addressof anything. This
3137 happens below, since it will fall into the default case. The only
3138 case we know something about an integer treated like a pointer is
3139 when it is the NULL pointer, and then we just say it points to
3142 Do not do that if -fno-delete-null-pointer-checks though, because
3143 in that case *NULL does not fail, so it _should_ alias *anything.
3144 It is not worth adding a new option or renaming the existing one,
3145 since this case is relatively obscure. */
3146 if (flag_delete_null_pointer_checks
3147 && ((TREE_CODE (t) == INTEGER_CST
3148 && integer_zerop (t))
3149 /* The only valid CONSTRUCTORs in gimple with pointer typed
3150 elements are zero-initializer. */
3151 || TREE_CODE (t) == CONSTRUCTOR))
3153 temp.var = nothing_id;
3154 temp.type = ADDRESSOF;
3156 VEC_safe_push (ce_s, heap, *results, &temp);
3160 /* String constants are read-only. */
3161 if (TREE_CODE (t) == STRING_CST)
3163 temp.var = readonly_id;
3166 VEC_safe_push (ce_s, heap, *results, &temp);
3170 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3172 case tcc_expression:
3174 switch (TREE_CODE (t))
3177 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3185 switch (TREE_CODE (t))
3189 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3194 case ARRAY_RANGE_REF:
3196 get_constraint_for_component_ref (t, results, address_p);
3198 case VIEW_CONVERT_EXPR:
3199 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3201 /* We are missing handling for TARGET_MEM_REF here. */
3206 case tcc_exceptional:
3208 switch (TREE_CODE (t))
3212 get_constraint_for_ssa_var (t, results, address_p);
3219 case tcc_declaration:
3221 get_constraint_for_ssa_var (t, results, address_p);
3227 /* The default fallback is a constraint from anything. */
3228 temp.type = ADDRESSOF;
3229 temp.var = anything_id;
3231 VEC_safe_push (ce_s, heap, *results, &temp);
3234 /* Given a gimple tree T, return the constraint expression vector for it. */
3237 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3239 gcc_assert (VEC_length (ce_s, *results) == 0);
3241 get_constraint_for_1 (t, results, false);
3245 /* Efficiently generates constraints from all entries in *RHSC to all
3246 entries in *LHSC. */
3249 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3251 struct constraint_expr *lhsp, *rhsp;
3254 if (VEC_length (ce_s, lhsc) <= 1
3255 || VEC_length (ce_s, rhsc) <= 1)
3257 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3258 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3259 process_constraint (new_constraint (*lhsp, *rhsp));
3263 struct constraint_expr tmp;
3264 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3265 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3266 process_constraint (new_constraint (tmp, *rhsp));
3267 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3268 process_constraint (new_constraint (*lhsp, tmp));
3272 /* Handle aggregate copies by expanding into copies of the respective
3273 fields of the structures. */
3276 do_structure_copy (tree lhsop, tree rhsop)
3278 struct constraint_expr *lhsp, *rhsp;
3279 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3282 get_constraint_for (lhsop, &lhsc);
3283 get_constraint_for (rhsop, &rhsc);
3284 lhsp = VEC_index (ce_s, lhsc, 0);
3285 rhsp = VEC_index (ce_s, rhsc, 0);
3286 if (lhsp->type == DEREF
3287 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3288 || rhsp->type == DEREF)
3289 process_all_all_constraints (lhsc, rhsc);
3290 else if (lhsp->type == SCALAR
3291 && (rhsp->type == SCALAR
3292 || rhsp->type == ADDRESSOF))
3294 tree lhsbase, rhsbase;
3295 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3296 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3298 lhsbase = get_ref_base_and_extent (lhsop, &lhsoffset,
3299 &lhssize, &lhsmaxsize);
3300 rhsbase = get_ref_base_and_extent (rhsop, &rhsoffset,
3301 &rhssize, &rhsmaxsize);
3302 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3304 varinfo_t lhsv, rhsv;
3305 rhsp = VEC_index (ce_s, rhsc, k);
3306 lhsv = get_varinfo (lhsp->var);
3307 rhsv = get_varinfo (rhsp->var);
3308 if (lhsv->may_have_pointers
3309 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3310 rhsv->offset + lhsoffset, rhsv->size))
3311 process_constraint (new_constraint (*lhsp, *rhsp));
3312 if (lhsv->offset + rhsoffset + lhsv->size
3313 > rhsv->offset + lhsoffset + rhsv->size)
3316 if (k >= VEC_length (ce_s, rhsc))
3326 VEC_free (ce_s, heap, lhsc);
3327 VEC_free (ce_s, heap, rhsc);
3330 /* Create a constraint ID = OP. */
3333 make_constraint_to (unsigned id, tree op)
3335 VEC(ce_s, heap) *rhsc = NULL;
3336 struct constraint_expr *c;
3337 struct constraint_expr includes;
3341 includes.offset = 0;
3342 includes.type = SCALAR;
3344 get_constraint_for (op, &rhsc);
3345 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3346 process_constraint (new_constraint (includes, *c));
3347 VEC_free (ce_s, heap, rhsc);
3350 /* Make constraints necessary to make OP escape. */
3353 make_escape_constraint (tree op)
3355 make_constraint_to (escaped_id, op);
3358 /* For non-IPA mode, generate constraints necessary for a call on the
3362 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3364 struct constraint_expr rhsc;
3367 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3369 tree arg = gimple_call_arg (stmt, i);
3371 /* Find those pointers being passed, and make sure they end up
3372 pointing to anything. */
3373 if (could_have_pointers (arg))
3374 make_escape_constraint (arg);
3377 /* The static chain escapes as well. */
3378 if (gimple_call_chain (stmt))
3379 make_escape_constraint (gimple_call_chain (stmt));
3381 /* And if we applied NRV the address of the return slot escapes as well. */
3382 if (gimple_call_return_slot_opt_p (stmt)
3383 && gimple_call_lhs (stmt) != NULL_TREE
3384 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3386 VEC(ce_s, heap) *tmpc = NULL;
3387 struct constraint_expr lhsc, *c;
3388 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3389 lhsc.var = escaped_id;
3392 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3393 process_constraint (new_constraint (lhsc, *c));
3394 VEC_free(ce_s, heap, tmpc);
3397 /* Regular functions return nonlocal memory. */
3398 rhsc.var = nonlocal_id;
3401 VEC_safe_push (ce_s, heap, *results, &rhsc);
3404 /* For non-IPA mode, generate constraints necessary for a call
3405 that returns a pointer and assigns it to LHS. This simply makes
3406 the LHS point to global and escaped variables. */
3409 handle_lhs_call (tree lhs, int flags, VEC(ce_s, heap) *rhsc)
3411 VEC(ce_s, heap) *lhsc = NULL;
3413 struct constraint_expr *lhsp;
3415 get_constraint_for (lhs, &lhsc);
3417 if (flags & ECF_MALLOC)
3419 struct constraint_expr rhsc;
3420 tree heapvar = heapvar_lookup (lhs);
3423 if (heapvar == NULL)
3425 heapvar = create_tmp_var_raw (ptr_type_node, "HEAP");
3426 DECL_EXTERNAL (heapvar) = 1;
3427 get_var_ann (heapvar)->is_heapvar = 1;
3428 if (gimple_referenced_vars (cfun))
3429 add_referenced_var (heapvar);
3430 heapvar_insert (lhs, heapvar);
3433 rhsc.var = create_variable_info_for (heapvar,
3434 alias_get_name (heapvar));
3435 vi = get_varinfo (rhsc.var);
3436 vi->is_artificial_var = 1;
3437 vi->is_heap_var = 1;
3438 vi->is_unknown_size_var = true;
3441 rhsc.type = ADDRESSOF;
3443 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
3444 process_constraint (new_constraint (*lhsp, rhsc));
3446 else if (VEC_length (ce_s, rhsc) > 0)
3448 /* If the store is to a global decl make sure to
3449 add proper escape constraints. */
3450 lhs = get_base_address (lhs);
3453 && is_global_var (lhs))
3455 struct constraint_expr tmpc;
3456 tmpc.var = escaped_id;
3459 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3461 process_all_all_constraints (lhsc, rhsc);
3463 VEC_free (ce_s, heap, lhsc);
3466 /* For non-IPA mode, generate constraints necessary for a call of a
3467 const function that returns a pointer in the statement STMT. */
3470 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3472 struct constraint_expr rhsc;
3475 /* Treat nested const functions the same as pure functions as far
3476 as the static chain is concerned. */
3477 if (gimple_call_chain (stmt))
3479 make_constraint_to (callused_id, gimple_call_chain (stmt));
3480 rhsc.var = callused_id;
3483 VEC_safe_push (ce_s, heap, *results, &rhsc);
3486 /* May return arguments. */
3487 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3489 tree arg = gimple_call_arg (stmt, k);
3491 if (could_have_pointers (arg))
3493 VEC(ce_s, heap) *argc = NULL;
3495 struct constraint_expr *argp;
3496 get_constraint_for (arg, &argc);
3497 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3498 VEC_safe_push (ce_s, heap, *results, argp);
3499 VEC_free(ce_s, heap, argc);
3503 /* May return addresses of globals. */
3504 rhsc.var = nonlocal_id;
3506 rhsc.type = ADDRESSOF;
3507 VEC_safe_push (ce_s, heap, *results, &rhsc);
3510 /* For non-IPA mode, generate constraints necessary for a call to a
3511 pure function in statement STMT. */
3514 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3516 struct constraint_expr rhsc;
3518 bool need_callused = false;
3520 /* Memory reached from pointer arguments is call-used. */
3521 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3523 tree arg = gimple_call_arg (stmt, i);
3525 if (could_have_pointers (arg))
3527 make_constraint_to (callused_id, arg);
3528 need_callused = true;
3532 /* The static chain is used as well. */
3533 if (gimple_call_chain (stmt))
3535 make_constraint_to (callused_id, gimple_call_chain (stmt));
3536 need_callused = true;
3539 /* Pure functions may return callused and nonlocal memory. */
3542 rhsc.var = callused_id;
3545 VEC_safe_push (ce_s, heap, *results, &rhsc);
3547 rhsc.var = nonlocal_id;
3550 VEC_safe_push (ce_s, heap, *results, &rhsc);
3553 /* Walk statement T setting up aliasing constraints according to the
3554 references found in T. This function is the main part of the
3555 constraint builder. AI points to auxiliary alias information used
3556 when building alias sets and computing alias grouping heuristics. */
3559 find_func_aliases (gimple origt)
3562 VEC(ce_s, heap) *lhsc = NULL;
3563 VEC(ce_s, heap) *rhsc = NULL;
3564 struct constraint_expr *c;
3566 /* Now build constraints expressions. */
3567 if (gimple_code (t) == GIMPLE_PHI)
3569 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
3571 /* Only care about pointers and structures containing
3573 if (could_have_pointers (gimple_phi_result (t)))
3578 /* For a phi node, assign all the arguments to
3580 get_constraint_for (gimple_phi_result (t), &lhsc);
3581 for (i = 0; i < gimple_phi_num_args (t); i++)
3584 tree strippedrhs = PHI_ARG_DEF (t, i);
3586 STRIP_NOPS (strippedrhs);
3587 rhstype = TREE_TYPE (strippedrhs);
3588 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
3590 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
3592 struct constraint_expr *c2;
3593 while (VEC_length (ce_s, rhsc) > 0)
3595 c2 = VEC_last (ce_s, rhsc);
3596 process_constraint (new_constraint (*c, *c2));
3597 VEC_pop (ce_s, rhsc);
3603 /* In IPA mode, we need to generate constraints to pass call
3604 arguments through their calls. There are two cases,
3605 either a GIMPLE_CALL returning a value, or just a plain
3606 GIMPLE_CALL when we are not.
3608 In non-ipa mode, we need to generate constraints for each
3609 pointer passed by address. */
3610 else if (is_gimple_call (t))
3613 if ((fndecl = gimple_call_fndecl (t)) != NULL_TREE
3614 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
3615 /* ??? All builtins that are handled here need to be handled
3616 in the alias-oracle query functions explicitly! */
3617 switch (DECL_FUNCTION_CODE (fndecl))
3619 /* All the following functions return a pointer to the same object
3620 as their first argument points to. The functions do not add
3621 to the ESCAPED solution. The functions make the first argument
3622 pointed to memory point to what the second argument pointed to
3623 memory points to. */
3624 case BUILT_IN_STRCPY:
3625 case BUILT_IN_STRNCPY:
3626 case BUILT_IN_BCOPY:
3627 case BUILT_IN_MEMCPY:
3628 case BUILT_IN_MEMMOVE:
3629 case BUILT_IN_MEMPCPY:
3630 case BUILT_IN_STPCPY:
3631 case BUILT_IN_STPNCPY:
3632 case BUILT_IN_STRCAT:
3633 case BUILT_IN_STRNCAT:
3635 tree res = gimple_call_lhs (t);
3636 tree dest = gimple_call_arg (t, 0);
3637 tree src = gimple_call_arg (t, 1);
3638 if (res != NULL_TREE)
3640 get_constraint_for (res, &lhsc);
3641 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
3642 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
3643 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
3644 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
3646 get_constraint_for (dest, &rhsc);
3647 process_all_all_constraints (lhsc, rhsc);
3648 VEC_free (ce_s, heap, lhsc);
3649 VEC_free (ce_s, heap, rhsc);
3651 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
3652 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
3655 process_all_all_constraints (lhsc, rhsc);
3656 VEC_free (ce_s, heap, lhsc);
3657 VEC_free (ce_s, heap, rhsc);
3660 case BUILT_IN_MEMSET:
3662 tree res = gimple_call_lhs (t);
3663 tree dest = gimple_call_arg (t, 0);
3666 struct constraint_expr ac;
3667 if (res != NULL_TREE)
3669 get_constraint_for (res, &lhsc);
3670 get_constraint_for (dest, &rhsc);
3671 process_all_all_constraints (lhsc, rhsc);
3672 VEC_free (ce_s, heap, lhsc);
3673 VEC_free (ce_s, heap, rhsc);
3675 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
3677 if (flag_delete_null_pointer_checks
3678 && integer_zerop (gimple_call_arg (t, 1)))
3680 ac.type = ADDRESSOF;
3681 ac.var = nothing_id;
3686 ac.var = integer_id;
3689 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3690 process_constraint (new_constraint (*lhsp, ac));
3691 VEC_free (ce_s, heap, lhsc);
3694 /* All the following functions do not return pointers, do not
3695 modify the points-to sets of memory reachable from their
3696 arguments and do not add to the ESCAPED solution. */
3697 case BUILT_IN_SINCOS:
3698 case BUILT_IN_SINCOSF:
3699 case BUILT_IN_SINCOSL:
3700 case BUILT_IN_FREXP:
3701 case BUILT_IN_FREXPF:
3702 case BUILT_IN_FREXPL:
3703 case BUILT_IN_GAMMA_R:
3704 case BUILT_IN_GAMMAF_R:
3705 case BUILT_IN_GAMMAL_R:
3706 case BUILT_IN_LGAMMA_R:
3707 case BUILT_IN_LGAMMAF_R:
3708 case BUILT_IN_LGAMMAL_R:
3710 case BUILT_IN_MODFF:
3711 case BUILT_IN_MODFL:
3712 case BUILT_IN_REMQUO:
3713 case BUILT_IN_REMQUOF:
3714 case BUILT_IN_REMQUOL:
3717 /* printf-style functions may have hooks to set pointers to
3718 point to somewhere into the generated string. Leave them
3719 for a later excercise... */
3721 /* Fallthru to general call handling. */;
3725 VEC(ce_s, heap) *rhsc = NULL;
3726 int flags = gimple_call_flags (t);
3728 /* Const functions can return their arguments and addresses
3729 of global memory but not of escaped memory. */
3730 if (flags & (ECF_CONST|ECF_NOVOPS))
3732 if (gimple_call_lhs (t)
3733 && could_have_pointers (gimple_call_lhs (t)))
3734 handle_const_call (t, &rhsc);
3736 /* Pure functions can return addresses in and of memory
3737 reachable from their arguments, but they are not an escape
3738 point for reachable memory of their arguments. */
3739 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
3740 handle_pure_call (t, &rhsc);
3742 handle_rhs_call (t, &rhsc);
3743 if (gimple_call_lhs (t)
3744 && could_have_pointers (gimple_call_lhs (t)))
3745 handle_lhs_call (gimple_call_lhs (t), flags, rhsc);
3746 VEC_free (ce_s, heap, rhsc);
3756 lhsop = gimple_call_lhs (t);
3757 decl = gimple_call_fndecl (t);
3759 /* If we can directly resolve the function being called, do so.
3760 Otherwise, it must be some sort of indirect expression that
3761 we should still be able to handle. */
3763 fi = get_vi_for_tree (decl);
3766 decl = gimple_call_fn (t);
3767 fi = get_vi_for_tree (decl);
3770 /* Assign all the passed arguments to the appropriate incoming
3771 parameters of the function. */
3772 for (j = 0; j < gimple_call_num_args (t); j++)
3774 struct constraint_expr lhs ;
3775 struct constraint_expr *rhsp;
3776 tree arg = gimple_call_arg (t, j);
3778 get_constraint_for (arg, &rhsc);
3779 if (TREE_CODE (decl) != FUNCTION_DECL)
3788 lhs.var = first_vi_for_offset (fi, i)->id;
3791 while (VEC_length (ce_s, rhsc) != 0)
3793 rhsp = VEC_last (ce_s, rhsc);
3794 process_constraint (new_constraint (lhs, *rhsp));
3795 VEC_pop (ce_s, rhsc);
3800 /* If we are returning a value, assign it to the result. */
3803 struct constraint_expr rhs;
3804 struct constraint_expr *lhsp;
3807 get_constraint_for (lhsop, &lhsc);
3808 if (TREE_CODE (decl) != FUNCTION_DECL)
3817 rhs.var = first_vi_for_offset (fi, i)->id;
3820 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
3821 process_constraint (new_constraint (*lhsp, rhs));
3825 /* Otherwise, just a regular assignment statement. Only care about
3826 operations with pointer result, others are dealt with as escape
3827 points if they have pointer operands. */
3828 else if (is_gimple_assign (t)
3829 && could_have_pointers (gimple_assign_lhs (t)))
3831 /* Otherwise, just a regular assignment statement. */
3832 tree lhsop = gimple_assign_lhs (t);
3833 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
3835 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
3836 do_structure_copy (lhsop, rhsop);
3839 struct constraint_expr temp;
3840 get_constraint_for (lhsop, &lhsc);
3842 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
3843 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
3844 gimple_assign_rhs2 (t), &rhsc);
3845 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
3846 && !(POINTER_TYPE_P (gimple_expr_type (t))
3847 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
3848 || gimple_assign_single_p (t))
3849 get_constraint_for (rhsop, &rhsc);
3852 temp.type = ADDRESSOF;
3853 temp.var = anything_id;
3855 VEC_safe_push (ce_s, heap, rhsc, &temp);
3857 process_all_all_constraints (lhsc, rhsc);
3859 /* If there is a store to a global variable the rhs escapes. */
3860 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
3862 && is_global_var (lhsop))
3863 make_escape_constraint (rhsop);
3865 /* For conversions of pointers to non-pointers the pointer escapes. */
3866 else if (gimple_assign_cast_p (t)
3867 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
3868 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
3870 make_escape_constraint (gimple_assign_rhs1 (t));
3872 /* Handle asms conservatively by adding escape constraints to everything. */
3873 else if (gimple_code (t) == GIMPLE_ASM)
3875 unsigned i, noutputs;
3876 const char **oconstraints;
3877 const char *constraint;
3878 bool allows_mem, allows_reg, is_inout;
3880 noutputs = gimple_asm_noutputs (t);
3881 oconstraints = XALLOCAVEC (const char *, noutputs);
3883 for (i = 0; i < noutputs; ++i)
3885 tree link = gimple_asm_output_op (t, i);
3886 tree op = TREE_VALUE (link);
3888 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
3889 oconstraints[i] = constraint;
3890 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
3891 &allows_reg, &is_inout);
3893 /* A memory constraint makes the address of the operand escape. */
3894 if (!allows_reg && allows_mem)
3895 make_escape_constraint (build_fold_addr_expr (op));
3897 /* The asm may read global memory, so outputs may point to
3898 any global memory. */
3899 if (op && could_have_pointers (op))
3901 VEC(ce_s, heap) *lhsc = NULL;
3902 struct constraint_expr rhsc, *lhsp;
3904 get_constraint_for (op, &lhsc);
3905 rhsc.var = nonlocal_id;
3908 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
3909 process_constraint (new_constraint (*lhsp, rhsc));
3910 VEC_free (ce_s, heap, lhsc);
3913 for (i = 0; i < gimple_asm_ninputs (t); ++i)
3915 tree link = gimple_asm_input_op (t, i);
3916 tree op = TREE_VALUE (link);
3918 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
3920 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
3921 &allows_mem, &allows_reg);
3923 /* A memory constraint makes the address of the operand escape. */
3924 if (!allows_reg && allows_mem)
3925 make_escape_constraint (build_fold_addr_expr (op));
3926 /* Strictly we'd only need the constraint to ESCAPED if
3927 the asm clobbers memory, otherwise using CALLUSED
3929 else if (op && could_have_pointers (op))
3930 make_escape_constraint (op);
3934 VEC_free (ce_s, heap, rhsc);
3935 VEC_free (ce_s, heap, lhsc);
3939 /* Find the first varinfo in the same variable as START that overlaps with
3940 OFFSET. Return NULL if we can't find one. */
3943 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
3945 /* If the offset is outside of the variable, bail out. */
3946 if (offset >= start->fullsize)
3949 /* If we cannot reach offset from start, lookup the first field
3950 and start from there. */
3951 if (start->offset > offset)
3952 start = lookup_vi_for_tree (start->decl);
3956 /* We may not find a variable in the field list with the actual
3957 offset when when we have glommed a structure to a variable.
3958 In that case, however, offset should still be within the size
3960 if (offset >= start->offset
3961 && offset < (start->offset + start->size))
3970 /* Find the first varinfo in the same variable as START that overlaps with
3971 OFFSET. If there is no such varinfo the varinfo directly preceding
3972 OFFSET is returned. */
3975 first_or_preceding_vi_for_offset (varinfo_t start,
3976 unsigned HOST_WIDE_INT offset)
3978 /* If we cannot reach offset from start, lookup the first field
3979 and start from there. */
3980 if (start->offset > offset)
3981 start = lookup_vi_for_tree (start->decl);
3983 /* We may not find a variable in the field list with the actual
3984 offset when when we have glommed a structure to a variable.
3985 In that case, however, offset should still be within the size
3987 If we got beyond the offset we look for return the field
3988 directly preceding offset which may be the last field. */
3990 && offset >= start->offset
3991 && !(offset < (start->offset + start->size)))
3992 start = start->next;
3998 /* Insert the varinfo FIELD into the field list for BASE, at the front
4002 insert_into_field_list (varinfo_t base, varinfo_t field)
4004 varinfo_t prev = base;
4005 varinfo_t curr = base->next;
4011 /* Insert the varinfo FIELD into the field list for BASE, ordered by
4015 insert_into_field_list_sorted (varinfo_t base, varinfo_t field)
4017 varinfo_t prev = base;
4018 varinfo_t curr = base->next;
4029 if (field->offset <= curr->offset)
4034 field->next = prev->next;
4039 /* This structure is used during pushing fields onto the fieldstack
4040 to track the offset of the field, since bitpos_of_field gives it
4041 relative to its immediate containing type, and we want it relative
4042 to the ultimate containing object. */
4046 /* Offset from the base of the base containing object to this field. */
4047 HOST_WIDE_INT offset;
4049 /* Size, in bits, of the field. */
4050 unsigned HOST_WIDE_INT size;
4052 unsigned has_unknown_size : 1;
4054 unsigned may_have_pointers : 1;
4056 typedef struct fieldoff fieldoff_s;
4058 DEF_VEC_O(fieldoff_s);
4059 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4061 /* qsort comparison function for two fieldoff's PA and PB */
4064 fieldoff_compare (const void *pa, const void *pb)
4066 const fieldoff_s *foa = (const fieldoff_s *)pa;
4067 const fieldoff_s *fob = (const fieldoff_s *)pb;
4068 unsigned HOST_WIDE_INT foasize, fobsize;
4070 if (foa->offset < fob->offset)
4072 else if (foa->offset > fob->offset)
4075 foasize = foa->size;
4076 fobsize = fob->size;
4077 if (foasize < fobsize)
4079 else if (foasize > fobsize)
4084 /* Sort a fieldstack according to the field offset and sizes. */
4086 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4088 qsort (VEC_address (fieldoff_s, fieldstack),
4089 VEC_length (fieldoff_s, fieldstack),
4090 sizeof (fieldoff_s),
4094 /* Return true if V is a tree that we can have subvars for.
4095 Normally, this is any aggregate type. Also complex
4096 types which are not gimple registers can have subvars. */
4099 var_can_have_subvars (const_tree v)
4101 /* Volatile variables should never have subvars. */
4102 if (TREE_THIS_VOLATILE (v))
4105 /* Non decls or memory tags can never have subvars. */
4109 /* Aggregates without overlapping fields can have subvars. */
4110 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4116 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4117 the fields of TYPE onto fieldstack, recording their offsets along
4120 OFFSET is used to keep track of the offset in this entire
4121 structure, rather than just the immediately containing structure.
4122 Returns the number of fields pushed. */
4125 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4126 HOST_WIDE_INT offset)
4131 if (TREE_CODE (type) != RECORD_TYPE)
4134 /* If the vector of fields is growing too big, bail out early.
4135 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4137 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4140 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4141 if (TREE_CODE (field) == FIELD_DECL)
4145 HOST_WIDE_INT foff = bitpos_of_field (field);
4147 if (!var_can_have_subvars (field)
4148 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4149 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4151 else if (!(pushed = push_fields_onto_fieldstack
4152 (TREE_TYPE (field), fieldstack, offset + foff))
4153 && (DECL_SIZE (field)
4154 && !integer_zerop (DECL_SIZE (field))))
4155 /* Empty structures may have actual size, like in C++. So
4156 see if we didn't push any subfields and the size is
4157 nonzero, push the field onto the stack. */
4162 fieldoff_s *pair = NULL;
4163 bool has_unknown_size = false;
4165 if (!VEC_empty (fieldoff_s, *fieldstack))
4166 pair = VEC_last (fieldoff_s, *fieldstack);
4168 if (!DECL_SIZE (field)
4169 || !host_integerp (DECL_SIZE (field), 1))
4170 has_unknown_size = true;
4172 /* If adjacent fields do not contain pointers merge them. */
4174 && !pair->may_have_pointers
4175 && !could_have_pointers (field)
4176 && !pair->has_unknown_size
4177 && !has_unknown_size
4178 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
4180 pair = VEC_last (fieldoff_s, *fieldstack);
4181 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
4185 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
4186 pair->offset = offset + foff;
4187 pair->has_unknown_size = has_unknown_size;
4188 if (!has_unknown_size)
4189 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
4192 pair->may_have_pointers = could_have_pointers (field);
4203 /* Create a constraint ID = &FROM. */
4206 make_constraint_from (varinfo_t vi, int from)
4208 struct constraint_expr lhs, rhs;
4216 rhs.type = ADDRESSOF;
4217 process_constraint (new_constraint (lhs, rhs));
4220 /* Create a constraint ID = FROM. */
4223 make_copy_constraint (varinfo_t vi, int from)
4225 struct constraint_expr lhs, rhs;
4234 process_constraint (new_constraint (lhs, rhs));
4237 /* Count the number of arguments DECL has, and set IS_VARARGS to true
4238 if it is a varargs function. */
4241 count_num_arguments (tree decl, bool *is_varargs)
4246 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl));
4250 if (TREE_VALUE (t) == void_type_node)
4260 /* Creation function node for DECL, using NAME, and return the index
4261 of the variable we've created for the function. */
4264 create_function_info_for (tree decl, const char *name)
4266 unsigned int index = VEC_length (varinfo_t, varmap);
4270 bool is_varargs = false;
4272 /* Create the variable info. */
4274 vi = new_var_info (decl, index, name);
4277 vi->fullsize = count_num_arguments (decl, &is_varargs) + 1;
4278 insert_vi_for_tree (vi->decl, vi);
4279 VEC_safe_push (varinfo_t, heap, varmap, vi);
4283 /* If it's varargs, we don't know how many arguments it has, so we
4289 vi->is_unknown_size_var = true;
4294 arg = DECL_ARGUMENTS (decl);
4296 /* Set up variables for each argument. */
4297 for (i = 1; i < vi->fullsize; i++)
4300 const char *newname;
4302 unsigned int newindex;
4303 tree argdecl = decl;
4308 newindex = VEC_length (varinfo_t, varmap);
4309 asprintf (&tempname, "%s.arg%d", name, i-1);
4310 newname = ggc_strdup (tempname);
4313 argvi = new_var_info (argdecl, newindex, newname);
4314 VEC_safe_push (varinfo_t, heap, varmap, argvi);
4317 argvi->is_full_var = true;
4318 argvi->fullsize = vi->fullsize;
4319 insert_into_field_list_sorted (vi, argvi);
4320 stats.total_vars ++;
4323 insert_vi_for_tree (arg, argvi);
4324 arg = TREE_CHAIN (arg);
4328 /* Create a variable for the return var. */
4329 if (DECL_RESULT (decl) != NULL
4330 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
4333 const char *newname;
4335 unsigned int newindex;
4336 tree resultdecl = decl;
4340 if (DECL_RESULT (decl))
4341 resultdecl = DECL_RESULT (decl);
4343 newindex = VEC_length (varinfo_t, varmap);
4344 asprintf (&tempname, "%s.result", name);
4345 newname = ggc_strdup (tempname);
4348 resultvi = new_var_info (resultdecl, newindex, newname);
4349 VEC_safe_push (varinfo_t, heap, varmap, resultvi);
4350 resultvi->offset = i;
4352 resultvi->fullsize = vi->fullsize;
4353 resultvi->is_full_var = true;
4354 insert_into_field_list_sorted (vi, resultvi);
4355 stats.total_vars ++;
4356 if (DECL_RESULT (decl))
4357 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
4363 /* Return true if FIELDSTACK contains fields that overlap.
4364 FIELDSTACK is assumed to be sorted by offset. */
4367 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
4369 fieldoff_s *fo = NULL;
4371 HOST_WIDE_INT lastoffset = -1;
4373 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
4375 if (fo->offset == lastoffset)
4377 lastoffset = fo->offset;
4382 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
4383 This will also create any varinfo structures necessary for fields
4387 create_variable_info_for (tree decl, const char *name)
4389 unsigned int index = VEC_length (varinfo_t, varmap);
4391 tree decl_type = TREE_TYPE (decl);
4392 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
4393 bool is_global = DECL_P (decl) ? is_global_var (decl) : false;
4394 VEC (fieldoff_s,heap) *fieldstack = NULL;
4396 if (TREE_CODE (decl) == FUNCTION_DECL && in_ipa_mode)
4397 return create_function_info_for (decl, name);
4399 if (var_can_have_subvars (decl) && use_field_sensitive
4401 || var_ann (decl)->noalias_state == 0)
4403 || !var_ann (decl)->is_heapvar))
4404 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
4406 /* If the variable doesn't have subvars, we may end up needing to
4407 sort the field list and create fake variables for all the
4409 vi = new_var_info (decl, index, name);
4411 vi->may_have_pointers = could_have_pointers (decl);
4413 || !host_integerp (declsize, 1))
4415 vi->is_unknown_size_var = true;
4421 vi->fullsize = TREE_INT_CST_LOW (declsize);
4422 vi->size = vi->fullsize;
4425 insert_vi_for_tree (vi->decl, vi);
4426 VEC_safe_push (varinfo_t, heap, varmap, vi);
4427 if (is_global && (!flag_whole_program || !in_ipa_mode)
4428 && vi->may_have_pointers)
4431 && var_ann (decl)->noalias_state == NO_ALIAS_ANYTHING)
4432 make_constraint_from (vi, vi->id);
4434 make_copy_constraint (vi, nonlocal_id);
4438 if (use_field_sensitive
4439 && !vi->is_unknown_size_var
4440 && var_can_have_subvars (decl)
4441 && VEC_length (fieldoff_s, fieldstack) > 1
4442 && VEC_length (fieldoff_s, fieldstack) <= MAX_FIELDS_FOR_FIELD_SENSITIVE)
4444 unsigned int newindex = VEC_length (varinfo_t, varmap);
4445 fieldoff_s *fo = NULL;
4446 bool notokay = false;
4449 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
4451 if (fo->has_unknown_size
4459 /* We can't sort them if we have a field with a variable sized type,
4460 which will make notokay = true. In that case, we are going to return
4461 without creating varinfos for the fields anyway, so sorting them is a
4465 sort_fieldstack (fieldstack);
4466 /* Due to some C++ FE issues, like PR 22488, we might end up
4467 what appear to be overlapping fields even though they,
4468 in reality, do not overlap. Until the C++ FE is fixed,
4469 we will simply disable field-sensitivity for these cases. */
4470 notokay = check_for_overlaps (fieldstack);
4474 if (VEC_length (fieldoff_s, fieldstack) != 0)
4475 fo = VEC_index (fieldoff_s, fieldstack, 0);
4477 if (fo == NULL || notokay)
4479 vi->is_unknown_size_var = 1;
4482 vi->is_full_var = true;
4483 VEC_free (fieldoff_s, heap, fieldstack);
4487 vi->size = fo->size;
4488 vi->offset = fo->offset;
4489 vi->may_have_pointers = fo->may_have_pointers;
4490 for (i = VEC_length (fieldoff_s, fieldstack) - 1;
4491 i >= 1 && VEC_iterate (fieldoff_s, fieldstack, i, fo);
4495 const char *newname = "NULL";
4498 newindex = VEC_length (varinfo_t, varmap);
4501 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
4502 "+" HOST_WIDE_INT_PRINT_DEC,
4503 vi->name, fo->offset, fo->size);
4504 newname = ggc_strdup (tempname);
4507 newvi = new_var_info (decl, newindex, newname);
4508 newvi->offset = fo->offset;
4509 newvi->size = fo->size;
4510 newvi->fullsize = vi->fullsize;
4511 newvi->may_have_pointers = fo->may_have_pointers;
4512 insert_into_field_list (vi, newvi);
4513 VEC_safe_push (varinfo_t, heap, varmap, newvi);
4514 if (is_global && (!flag_whole_program || !in_ipa_mode)
4515 && newvi->may_have_pointers)
4516 make_copy_constraint (newvi, nonlocal_id);
4522 vi->is_full_var = true;
4524 VEC_free (fieldoff_s, heap, fieldstack);
4529 /* Print out the points-to solution for VAR to FILE. */
4532 dump_solution_for_var (FILE *file, unsigned int var)
4534 varinfo_t vi = get_varinfo (var);
4538 if (find (var) != var)
4540 varinfo_t vipt = get_varinfo (find (var));
4541 fprintf (file, "%s = same as %s\n", vi->name, vipt->name);
4545 fprintf (file, "%s = { ", vi->name);
4546 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
4548 fprintf (file, "%s ", get_varinfo (i)->name);
4550 fprintf (file, "}\n");
4554 /* Print the points-to solution for VAR to stdout. */
4557 debug_solution_for_var (unsigned int var)
4559 dump_solution_for_var (stdout, var);
4562 /* Create varinfo structures for all of the variables in the
4563 function for intraprocedural mode. */
4566 intra_create_variable_infos (void)
4569 struct constraint_expr lhs, rhs;
4571 /* For each incoming pointer argument arg, create the constraint ARG
4572 = NONLOCAL or a dummy variable if flag_argument_noalias is set. */
4573 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
4577 if (!could_have_pointers (t))
4580 /* If flag_argument_noalias is set, then function pointer
4581 arguments are guaranteed not to point to each other. In that
4582 case, create an artificial variable PARM_NOALIAS and the
4583 constraint ARG = &PARM_NOALIAS. */
4584 if (POINTER_TYPE_P (TREE_TYPE (t)) && flag_argument_noalias > 0)
4587 tree heapvar = heapvar_lookup (t);
4591 lhs.var = get_vi_for_tree (t)->id;
4593 if (heapvar == NULL_TREE)
4596 heapvar = create_tmp_var_raw (ptr_type_node,
4598 DECL_EXTERNAL (heapvar) = 1;
4599 if (gimple_referenced_vars (cfun))
4600 add_referenced_var (heapvar);
4602 heapvar_insert (t, heapvar);
4604 ann = get_var_ann (heapvar);
4605 ann->is_heapvar = 1;
4606 if (flag_argument_noalias == 1)
4607 ann->noalias_state = NO_ALIAS;
4608 else if (flag_argument_noalias == 2)
4609 ann->noalias_state = NO_ALIAS_GLOBAL;
4610 else if (flag_argument_noalias == 3)
4611 ann->noalias_state = NO_ALIAS_ANYTHING;
4616 vi = get_vi_for_tree (heapvar);
4617 vi->is_artificial_var = 1;
4618 vi->is_heap_var = 1;
4619 vi->is_unknown_size_var = true;
4623 rhs.type = ADDRESSOF;
4625 for (p = get_varinfo (lhs.var); p; p = p->next)
4627 struct constraint_expr temp = lhs;
4629 process_constraint (new_constraint (temp, rhs));
4634 varinfo_t arg_vi = get_vi_for_tree (t);
4636 for (p = arg_vi; p; p = p->next)
4637 make_constraint_from (p, nonlocal_id);
4641 /* Add a constraint for a result decl that is passed by reference. */
4642 if (DECL_RESULT (cfun->decl)
4643 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
4645 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
4647 for (p = result_vi; p; p = p->next)
4648 make_constraint_from (p, nonlocal_id);
4651 /* Add a constraint for the incoming static chain parameter. */
4652 if (cfun->static_chain_decl != NULL_TREE)
4654 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
4656 for (p = chain_vi; p; p = p->next)
4657 make_constraint_from (p, nonlocal_id);
4661 /* Structure used to put solution bitmaps in a hashtable so they can
4662 be shared among variables with the same points-to set. */
4664 typedef struct shared_bitmap_info
4668 } *shared_bitmap_info_t;
4669 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
4671 static htab_t shared_bitmap_table;
4673 /* Hash function for a shared_bitmap_info_t */
4676 shared_bitmap_hash (const void *p)
4678 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
4679 return bi->hashcode;
4682 /* Equality function for two shared_bitmap_info_t's. */
4685 shared_bitmap_eq (const void *p1, const void *p2)
4687 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
4688 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
4689 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
4692 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
4693 existing instance if there is one, NULL otherwise. */
4696 shared_bitmap_lookup (bitmap pt_vars)
4699 struct shared_bitmap_info sbi;
4701 sbi.pt_vars = pt_vars;
4702 sbi.hashcode = bitmap_hash (pt_vars);
4704 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
4705 sbi.hashcode, NO_INSERT);
4709 return ((shared_bitmap_info_t) *slot)->pt_vars;
4713 /* Add a bitmap to the shared bitmap hashtable. */
4716 shared_bitmap_add (bitmap pt_vars)
4719 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
4721 sbi->pt_vars = pt_vars;
4722 sbi->hashcode = bitmap_hash (pt_vars);
4724 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
4725 sbi->hashcode, INSERT);
4726 gcc_assert (!*slot);
4727 *slot = (void *) sbi;
4731 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
4734 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
4739 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
4741 varinfo_t vi = get_varinfo (i);
4743 /* The only artificial variables that are allowed in a may-alias
4744 set are heap variables. */
4745 if (vi->is_artificial_var && !vi->is_heap_var)
4748 if (TREE_CODE (vi->decl) == VAR_DECL
4749 || TREE_CODE (vi->decl) == PARM_DECL
4750 || TREE_CODE (vi->decl) == RESULT_DECL)
4752 /* Add the decl to the points-to set. Note that the points-to
4753 set contains global variables. */
4754 bitmap_set_bit (into, DECL_UID (vi->decl));
4755 if (is_global_var (vi->decl))
4756 pt->vars_contains_global = true;
4762 static bool have_alias_info = false;
4764 /* Compute the points-to solution *PT for the variable VI. */
4767 find_what_var_points_to (varinfo_t vi, struct pt_solution *pt)
4771 bitmap finished_solution;
4773 tree ptr = vi->decl;
4775 memset (pt, 0, sizeof (struct pt_solution));
4777 /* This variable may have been collapsed, let's get the real
4779 vi = get_varinfo (find (vi->id));
4781 /* Translate artificial variables into SSA_NAME_PTR_INFO
4783 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
4785 varinfo_t vi = get_varinfo (i);
4787 if (vi->is_artificial_var)
4789 if (vi->id == nothing_id)
4791 else if (vi->id == escaped_id)
4793 else if (vi->id == callused_id)
4795 else if (vi->id == nonlocal_id)
4797 else if (vi->is_heap_var)
4798 /* We represent heapvars in the points-to set properly. */
4800 else if (vi->id == anything_id
4801 || vi->id == readonly_id
4802 || vi->id == integer_id)
4807 /* Instead of doing extra work, simply do not create
4808 elaborate points-to information for pt_anything pointers. */
4812 /* Share the final set of variables when possible. */
4813 finished_solution = BITMAP_GGC_ALLOC ();
4814 stats.points_to_sets_created++;
4816 if (TREE_CODE (ptr) == SSA_NAME)
4817 ptr = SSA_NAME_VAR (ptr);
4819 set_uids_in_ptset (finished_solution, vi->solution, pt);
4820 result = shared_bitmap_lookup (finished_solution);
4823 shared_bitmap_add (finished_solution);
4824 pt->vars = finished_solution;
4829 bitmap_clear (finished_solution);
4833 /* Given a pointer variable P, fill in its points-to set. */
4836 find_what_p_points_to (tree p)
4838 struct ptr_info_def *pi;
4842 /* For parameters, get at the points-to set for the actual parm
4844 if (TREE_CODE (p) == SSA_NAME
4845 && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
4846 && SSA_NAME_IS_DEFAULT_DEF (p))
4847 lookup_p = SSA_NAME_VAR (p);
4849 vi = lookup_vi_for_tree (lookup_p);
4853 pi = get_ptr_info (p);
4854 find_what_var_points_to (vi, &pi->pt);
4858 /* Query statistics for points-to solutions. */
4861 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
4862 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
4863 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
4864 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
4868 dump_pta_stats (FILE *s)
4870 fprintf (s, "\nPTA query stats:\n");
4871 fprintf (s, " pt_solution_includes: "
4872 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
4873 HOST_WIDE_INT_PRINT_DEC" queries\n",
4874 pta_stats.pt_solution_includes_no_alias,
4875 pta_stats.pt_solution_includes_no_alias
4876 + pta_stats.pt_solution_includes_may_alias);
4877 fprintf (s, " pt_solutions_intersect: "
4878 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
4879 HOST_WIDE_INT_PRINT_DEC" queries\n",
4880 pta_stats.pt_solutions_intersect_no_alias,
4881 pta_stats.pt_solutions_intersect_no_alias
4882 + pta_stats.pt_solutions_intersect_may_alias);
4886 /* Reset the points-to solution *PT to a conservative default
4887 (point to anything). */
4890 pt_solution_reset (struct pt_solution *pt)
4892 memset (pt, 0, sizeof (struct pt_solution));
4893 pt->anything = true;
4896 /* Return true if the points-to solution *PT is empty. */
4899 pt_solution_empty_p (struct pt_solution *pt)
4906 && !bitmap_empty_p (pt->vars))
4909 /* If the solution includes ESCAPED, check if that is empty. */
4911 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
4917 /* Return true if the points-to solution *PT includes global memory. */
4920 pt_solution_includes_global (struct pt_solution *pt)
4924 || pt->vars_contains_global)
4928 return pt_solution_includes_global (&cfun->gimple_df->escaped);
4933 /* Return true if the points-to solution *PT includes the variable
4934 declaration DECL. */
4937 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
4943 && is_global_var (decl))
4947 && bitmap_bit_p (pt->vars, DECL_UID (decl)))
4950 /* If the solution includes ESCAPED, check it. */
4952 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
4959 pt_solution_includes (struct pt_solution *pt, const_tree decl)
4961 bool res = pt_solution_includes_1 (pt, decl);
4963 ++pta_stats.pt_solution_includes_may_alias;
4965 ++pta_stats.pt_solution_includes_no_alias;
4969 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
4973 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
4975 if (pt1->anything || pt2->anything)
4978 /* If either points to unknown global memory and the other points to
4979 any global memory they alias. */
4982 || pt2->vars_contains_global))
4984 && pt1->vars_contains_global))
4987 /* Check the escaped solution if required. */
4988 if ((pt1->escaped || pt2->escaped)
4989 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
4991 /* If both point to escaped memory and that solution
4992 is not empty they alias. */
4993 if (pt1->escaped && pt2->escaped)
4996 /* If either points to escaped memory see if the escaped solution
4997 intersects with the other. */
4999 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5001 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
5005 /* Now both pointers alias if their points-to solution intersects. */
5008 && bitmap_intersect_p (pt1->vars, pt2->vars));
5012 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
5014 bool res = pt_solutions_intersect_1 (pt1, pt2);
5016 ++pta_stats.pt_solutions_intersect_may_alias;
5018 ++pta_stats.pt_solutions_intersect_no_alias;
5023 /* Dump points-to information to OUTFILE. */
5026 dump_sa_points_to_info (FILE *outfile)
5030 fprintf (outfile, "\nPoints-to sets\n\n");
5032 if (dump_flags & TDF_STATS)
5034 fprintf (outfile, "Stats:\n");
5035 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
5036 fprintf (outfile, "Non-pointer vars: %d\n",
5037 stats.nonpointer_vars);
5038 fprintf (outfile, "Statically unified vars: %d\n",
5039 stats.unified_vars_static);
5040 fprintf (outfile, "Dynamically unified vars: %d\n",
5041 stats.unified_vars_dynamic);
5042 fprintf (outfile, "Iterations: %d\n", stats.iterations);
5043 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
5044 fprintf (outfile, "Number of implicit edges: %d\n",
5045 stats.num_implicit_edges);
5048 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
5049 dump_solution_for_var (outfile, i);
5053 /* Debug points-to information to stderr. */
5056 debug_sa_points_to_info (void)
5058 dump_sa_points_to_info (stderr);
5062 /* Initialize the always-existing constraint variables for NULL
5063 ANYTHING, READONLY, and INTEGER */
5066 init_base_vars (void)
5068 struct constraint_expr lhs, rhs;
5070 /* Create the NULL variable, used to represent that a variable points
5072 nothing_tree = create_tmp_var_raw (void_type_node, "NULL");
5073 var_nothing = new_var_info (nothing_tree, nothing_id, "NULL");
5074 insert_vi_for_tree (nothing_tree, var_nothing);
5075 var_nothing->is_artificial_var = 1;
5076 var_nothing->offset = 0;
5077 var_nothing->size = ~0;
5078 var_nothing->fullsize = ~0;
5079 var_nothing->is_special_var = 1;
5080 VEC_safe_push (varinfo_t, heap, varmap, var_nothing);
5082 /* Create the ANYTHING variable, used to represent that a variable
5083 points to some unknown piece of memory. */
5084 anything_tree = create_tmp_var_raw (ptr_type_node, "ANYTHING");
5085 var_anything = new_var_info (anything_tree, anything_id, "ANYTHING");
5086 insert_vi_for_tree (anything_tree, var_anything);
5087 var_anything->is_artificial_var = 1;
5088 var_anything->size = ~0;
5089 var_anything->offset = 0;
5090 var_anything->next = NULL;
5091 var_anything->fullsize = ~0;
5092 var_anything->is_special_var = 1;
5094 /* Anything points to anything. This makes deref constraints just
5095 work in the presence of linked list and other p = *p type loops,
5096 by saying that *ANYTHING = ANYTHING. */
5097 VEC_safe_push (varinfo_t, heap, varmap, var_anything);
5099 lhs.var = anything_id;
5101 rhs.type = ADDRESSOF;
5102 rhs.var = anything_id;
5105 /* This specifically does not use process_constraint because
5106 process_constraint ignores all anything = anything constraints, since all
5107 but this one are redundant. */
5108 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
5110 /* Create the READONLY variable, used to represent that a variable
5111 points to readonly memory. */
5112 readonly_tree = create_tmp_var_raw (ptr_type_node, "READONLY");
5113 var_readonly = new_var_info (readonly_tree, readonly_id, "READONLY");
5114 var_readonly->is_artificial_var = 1;
5115 var_readonly->offset = 0;
5116 var_readonly->size = ~0;
5117 var_readonly->fullsize = ~0;
5118 var_readonly->next = NULL;
5119 var_readonly->is_special_var = 1;
5120 insert_vi_for_tree (readonly_tree, var_readonly);
5121 VEC_safe_push (varinfo_t, heap, varmap, var_readonly);
5123 /* readonly memory points to anything, in order to make deref
5124 easier. In reality, it points to anything the particular
5125 readonly variable can point to, but we don't track this
5128 lhs.var = readonly_id;
5130 rhs.type = ADDRESSOF;
5131 rhs.var = readonly_id; /* FIXME */
5133 process_constraint (new_constraint (lhs, rhs));
5135 /* Create the ESCAPED variable, used to represent the set of escaped
5137 escaped_tree = create_tmp_var_raw (ptr_type_node, "ESCAPED");
5138 var_escaped = new_var_info (escaped_tree, escaped_id, "ESCAPED");
5139 insert_vi_for_tree (escaped_tree, var_escaped);
5140 var_escaped->is_artificial_var = 1;
5141 var_escaped->offset = 0;
5142 var_escaped->size = ~0;
5143 var_escaped->fullsize = ~0;
5144 var_escaped->is_special_var = 0;
5145 VEC_safe_push (varinfo_t, heap, varmap, var_escaped);
5146 gcc_assert (VEC_index (varinfo_t, varmap, 3) == var_escaped);
5148 /* Create the NONLOCAL variable, used to represent the set of nonlocal
5150 nonlocal_tree = create_tmp_var_raw (ptr_type_node, "NONLOCAL");
5151 var_nonlocal = new_var_info (nonlocal_tree, nonlocal_id, "NONLOCAL");
5152 insert_vi_for_tree (nonlocal_tree, var_nonlocal);
5153 var_nonlocal->is_artificial_var = 1;
5154 var_nonlocal->offset = 0;
5155 var_nonlocal->size = ~0;
5156 var_nonlocal->fullsize = ~0;
5157 var_nonlocal->is_special_var = 1;
5158 VEC_safe_push (varinfo_t, heap, varmap, var_nonlocal);
5160 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
5162 lhs.var = escaped_id;
5165 rhs.var = escaped_id;
5167 process_constraint (new_constraint (lhs, rhs));
5169 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
5170 whole variable escapes. */
5172 lhs.var = escaped_id;
5175 rhs.var = escaped_id;
5176 rhs.offset = UNKNOWN_OFFSET;
5177 process_constraint (new_constraint (lhs, rhs));
5179 /* *ESCAPED = NONLOCAL. This is true because we have to assume
5180 everything pointed to by escaped points to what global memory can
5183 lhs.var = escaped_id;
5186 rhs.var = nonlocal_id;
5188 process_constraint (new_constraint (lhs, rhs));
5190 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
5191 global memory may point to global memory and escaped memory. */
5193 lhs.var = nonlocal_id;
5195 rhs.type = ADDRESSOF;
5196 rhs.var = nonlocal_id;
5198 process_constraint (new_constraint (lhs, rhs));
5199 rhs.type = ADDRESSOF;
5200 rhs.var = escaped_id;
5202 process_constraint (new_constraint (lhs, rhs));
5204 /* Create the CALLUSED variable, used to represent the set of call-used
5206 callused_tree = create_tmp_var_raw (ptr_type_node, "CALLUSED");
5207 var_callused = new_var_info (callused_tree, callused_id, "CALLUSED");
5208 insert_vi_for_tree (callused_tree, var_callused);
5209 var_callused->is_artificial_var = 1;
5210 var_callused->offset = 0;
5211 var_callused->size = ~0;
5212 var_callused->fullsize = ~0;
5213 var_callused->is_special_var = 0;
5214 VEC_safe_push (varinfo_t, heap, varmap, var_callused);
5216 /* CALLUSED = *CALLUSED, because call-used is may-deref'd at calls, etc. */
5218 lhs.var = callused_id;
5221 rhs.var = callused_id;
5223 process_constraint (new_constraint (lhs, rhs));
5225 /* CALLUSED = CALLUSED + UNKNOWN, because if a sub-field is call-used the
5226 whole variable is call-used. */
5228 lhs.var = callused_id;
5231 rhs.var = callused_id;
5232 rhs.offset = UNKNOWN_OFFSET;
5233 process_constraint (new_constraint (lhs, rhs));
5235 /* Create the STOREDANYTHING variable, used to represent the set of
5236 variables stored to *ANYTHING. */
5237 storedanything_tree = create_tmp_var_raw (ptr_type_node, "STOREDANYTHING");
5238 var_storedanything = new_var_info (storedanything_tree, storedanything_id,
5240 insert_vi_for_tree (storedanything_tree, var_storedanything);
5241 var_storedanything->is_artificial_var = 1;
5242 var_storedanything->offset = 0;
5243 var_storedanything->size = ~0;
5244 var_storedanything->fullsize = ~0;
5245 var_storedanything->is_special_var = 0;
5246 VEC_safe_push (varinfo_t, heap, varmap, var_storedanything);
5248 /* Create the INTEGER variable, used to represent that a variable points
5249 to what an INTEGER "points to". */
5250 integer_tree = create_tmp_var_raw (ptr_type_node, "INTEGER");
5251 var_integer = new_var_info (integer_tree, integer_id, "INTEGER");
5252 insert_vi_for_tree (integer_tree, var_integer);
5253 var_integer->is_artificial_var = 1;
5254 var_integer->size = ~0;
5255 var_integer->fullsize = ~0;
5256 var_integer->offset = 0;
5257 var_integer->next = NULL;
5258 var_integer->is_special_var = 1;
5259 VEC_safe_push (varinfo_t, heap, varmap, var_integer);
5261 /* INTEGER = ANYTHING, because we don't know where a dereference of
5262 a random integer will point to. */
5264 lhs.var = integer_id;
5266 rhs.type = ADDRESSOF;
5267 rhs.var = anything_id;
5269 process_constraint (new_constraint (lhs, rhs));
5272 /* Initialize things necessary to perform PTA */
5275 init_alias_vars (void)
5277 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
5279 bitmap_obstack_initialize (&pta_obstack);
5280 bitmap_obstack_initialize (&oldpta_obstack);
5281 bitmap_obstack_initialize (&predbitmap_obstack);
5283 constraint_pool = create_alloc_pool ("Constraint pool",
5284 sizeof (struct constraint), 30);
5285 variable_info_pool = create_alloc_pool ("Variable info pool",
5286 sizeof (struct variable_info), 30);
5287 constraints = VEC_alloc (constraint_t, heap, 8);
5288 varmap = VEC_alloc (varinfo_t, heap, 8);
5289 vi_for_tree = pointer_map_create ();
5291 memset (&stats, 0, sizeof (stats));
5292 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
5293 shared_bitmap_eq, free);
5297 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
5298 predecessor edges. */
5301 remove_preds_and_fake_succs (constraint_graph_t graph)
5305 /* Clear the implicit ref and address nodes from the successor
5307 for (i = 0; i < FIRST_REF_NODE; i++)
5309 if (graph->succs[i])
5310 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
5311 FIRST_REF_NODE * 2);
5314 /* Free the successor list for the non-ref nodes. */
5315 for (i = FIRST_REF_NODE; i < graph->size; i++)
5317 if (graph->succs[i])
5318 BITMAP_FREE (graph->succs[i]);
5321 /* Now reallocate the size of the successor list as, and blow away
5322 the predecessor bitmaps. */
5323 graph->size = VEC_length (varinfo_t, varmap);
5324 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
5326 free (graph->implicit_preds);
5327 graph->implicit_preds = NULL;
5328 free (graph->preds);
5329 graph->preds = NULL;
5330 bitmap_obstack_release (&predbitmap_obstack);
5333 /* Initialize the heapvar for statement mapping. */
5336 init_alias_heapvars (void)
5338 if (!heapvar_for_stmt)
5339 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, tree_map_eq,
5343 /* Delete the heapvar for statement mapping. */
5346 delete_alias_heapvars (void)
5348 if (heapvar_for_stmt)
5349 htab_delete (heapvar_for_stmt);
5350 heapvar_for_stmt = NULL;
5353 /* Create points-to sets for the current function. See the comments
5354 at the start of the file for an algorithmic overview. */
5357 compute_points_to_sets (void)
5359 struct scc_info *si;
5363 timevar_push (TV_TREE_PTA);
5366 init_alias_heapvars ();
5368 intra_create_variable_infos ();
5370 /* Now walk all statements and derive aliases. */
5373 gimple_stmt_iterator gsi;
5375 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
5377 gimple phi = gsi_stmt (gsi);
5379 if (is_gimple_reg (gimple_phi_result (phi)))
5380 find_func_aliases (phi);
5383 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
5385 gimple stmt = gsi_stmt (gsi);
5387 find_func_aliases (stmt);
5393 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
5394 dump_constraints (dump_file);
5399 "\nCollapsing static cycles and doing variable "
5402 init_graph (VEC_length (varinfo_t, varmap) * 2);
5405 fprintf (dump_file, "Building predecessor graph\n");
5406 build_pred_graph ();
5409 fprintf (dump_file, "Detecting pointer and location "
5411 si = perform_var_substitution (graph);
5414 fprintf (dump_file, "Rewriting constraints and unifying "
5416 rewrite_constraints (graph, si);
5418 build_succ_graph ();
5419 free_var_substitution_info (si);
5421 if (dump_file && (dump_flags & TDF_GRAPH))
5422 dump_constraint_graph (dump_file);
5424 move_complex_constraints (graph);
5427 fprintf (dump_file, "Uniting pointer but not location equivalent "
5429 unite_pointer_equivalences (graph);
5432 fprintf (dump_file, "Finding indirect cycles\n");
5433 find_indirect_cycles (graph);
5435 /* Implicit nodes and predecessors are no longer necessary at this
5437 remove_preds_and_fake_succs (graph);
5440 fprintf (dump_file, "Solving graph\n");
5442 solve_graph (graph);
5445 dump_sa_points_to_info (dump_file);
5447 /* Compute the points-to sets for ESCAPED and CALLUSED used for
5448 call-clobber analysis. */
5449 find_what_var_points_to (var_escaped, &cfun->gimple_df->escaped);
5450 find_what_var_points_to (var_callused, &cfun->gimple_df->callused);
5452 /* Make sure the ESCAPED solution (which is used as placeholder in
5453 other solutions) does not reference itself. This simplifies
5454 points-to solution queries. */
5455 cfun->gimple_df->escaped.escaped = 0;
5457 /* Compute the points-to sets for pointer SSA_NAMEs. */
5458 for (i = 0; i < num_ssa_names; ++i)
5460 tree ptr = ssa_name (i);
5462 && POINTER_TYPE_P (TREE_TYPE (ptr)))
5463 find_what_p_points_to (ptr);
5466 timevar_pop (TV_TREE_PTA);
5468 have_alias_info = true;
5472 /* Delete created points-to sets. */
5475 delete_points_to_sets (void)
5479 htab_delete (shared_bitmap_table);
5480 if (dump_file && (dump_flags & TDF_STATS))
5481 fprintf (dump_file, "Points to sets created:%d\n",
5482 stats.points_to_sets_created);
5484 pointer_map_destroy (vi_for_tree);
5485 bitmap_obstack_release (&pta_obstack);
5486 VEC_free (constraint_t, heap, constraints);
5488 for (i = 0; i < graph->size; i++)
5489 VEC_free (constraint_t, heap, graph->complex[i]);
5490 free (graph->complex);
5493 free (graph->succs);
5495 free (graph->pe_rep);
5496 free (graph->indirect_cycles);
5499 VEC_free (varinfo_t, heap, varmap);
5500 free_alloc_pool (variable_info_pool);
5501 free_alloc_pool (constraint_pool);
5502 have_alias_info = false;
5506 /* Compute points-to information for every SSA_NAME pointer in the
5507 current function and compute the transitive closure of escaped
5508 variables to re-initialize the call-clobber states of local variables. */
5511 compute_may_aliases (void)
5513 /* For each pointer P_i, determine the sets of variables that P_i may
5514 point-to. Compute the reachability set of escaped and call-used
5516 compute_points_to_sets ();
5518 /* Debugging dumps. */
5521 dump_alias_info (dump_file);
5523 if (dump_flags & TDF_DETAILS)
5524 dump_referenced_vars (dump_file);
5527 /* Deallocate memory used by aliasing data structures and the internal
5528 points-to solution. */
5529 delete_points_to_sets ();
5531 gcc_assert (!need_ssa_update_p (cfun));
5537 gate_tree_pta (void)
5539 return flag_tree_pta;
5542 /* A dummy pass to cause points-to information to be computed via
5543 TODO_rebuild_alias. */
5545 struct gimple_opt_pass pass_build_alias =
5550 gate_tree_pta, /* gate */
5554 0, /* static_pass_number */
5555 TV_NONE, /* tv_id */
5556 PROP_cfg | PROP_ssa, /* properties_required */
5557 0, /* properties_provided */
5558 0, /* properties_destroyed */
5559 0, /* todo_flags_start */
5560 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
5564 /* A dummy pass to cause points-to information to be computed via
5565 TODO_rebuild_alias. */
5567 struct gimple_opt_pass pass_build_ealias =
5571 "ealias", /* name */
5572 gate_tree_pta, /* gate */
5576 0, /* static_pass_number */
5577 TV_NONE, /* tv_id */
5578 PROP_cfg | PROP_ssa, /* properties_required */
5579 0, /* properties_provided */
5580 0, /* properties_destroyed */
5581 0, /* todo_flags_start */
5582 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
5587 /* Return true if we should execute IPA PTA. */
5591 return (flag_ipa_pta
5592 /* Don't bother doing anything if the program has errors. */
5593 && !(errorcount || sorrycount));
5596 /* Execute the driver for IPA PTA. */
5598 ipa_pta_execute (void)
5600 struct cgraph_node *node;
5601 struct scc_info *si;
5604 init_alias_heapvars ();
5607 for (node = cgraph_nodes; node; node = node->next)
5611 varid = create_function_info_for (node->decl,
5612 cgraph_node_name (node));
5613 if (node->local.externally_visible)
5615 varinfo_t fi = get_varinfo (varid);
5616 for (; fi; fi = fi->next)
5617 make_constraint_from (fi, anything_id);
5620 for (node = cgraph_nodes; node; node = node->next)
5624 struct function *func = DECL_STRUCT_FUNCTION (node->decl);
5626 tree old_func_decl = current_function_decl;
5629 "Generating constraints for %s\n",
5630 cgraph_node_name (node));
5632 current_function_decl = node->decl;
5634 FOR_EACH_BB_FN (bb, func)
5636 gimple_stmt_iterator gsi;
5638 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
5641 gimple phi = gsi_stmt (gsi);
5643 if (is_gimple_reg (gimple_phi_result (phi)))
5644 find_func_aliases (phi);
5647 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
5648 find_func_aliases (gsi_stmt (gsi));
5650 current_function_decl = old_func_decl;
5655 /* Make point to anything. */
5661 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
5662 dump_constraints (dump_file);
5667 "\nCollapsing static cycles and doing variable "
5670 init_graph (VEC_length (varinfo_t, varmap) * 2);
5671 build_pred_graph ();
5672 si = perform_var_substitution (graph);
5673 rewrite_constraints (graph, si);
5675 build_succ_graph ();
5676 free_var_substitution_info (si);
5677 move_complex_constraints (graph);
5678 unite_pointer_equivalences (graph);
5679 find_indirect_cycles (graph);
5681 /* Implicit nodes and predecessors are no longer necessary at this
5683 remove_preds_and_fake_succs (graph);
5686 fprintf (dump_file, "\nSolving graph\n");
5688 solve_graph (graph);
5691 dump_sa_points_to_info (dump_file);
5694 delete_alias_heapvars ();
5695 delete_points_to_sets ();
5699 struct simple_ipa_opt_pass pass_ipa_pta =
5704 gate_ipa_pta, /* gate */
5705 ipa_pta_execute, /* execute */
5708 0, /* static_pass_number */
5709 TV_IPA_PTA, /* tv_id */
5710 0, /* properties_required */
5711 0, /* properties_provided */
5712 0, /* properties_destroyed */
5713 0, /* todo_flags_start */
5714 TODO_update_ssa /* todo_flags_finish */
5719 #include "gt-tree-ssa-structalias.h"