1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dberlin@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "basic-block.h"
33 #include "tree-flow.h"
34 #include "tree-inline.h"
35 #include "diagnostic-core.h"
40 #include "tree-pass.h"
42 #include "alloc-pool.h"
43 #include "splay-tree.h"
47 #include "pointer-set.h"
49 /* The idea behind this analyzer is to generate set constraints from the
50 program, then solve the resulting constraints in order to generate the
53 Set constraints are a way of modeling program analysis problems that
54 involve sets. They consist of an inclusion constraint language,
55 describing the variables (each variable is a set) and operations that
56 are involved on the variables, and a set of rules that derive facts
57 from these operations. To solve a system of set constraints, you derive
58 all possible facts under the rules, which gives you the correct sets
61 See "Efficient Field-sensitive pointer analysis for C" by "David
62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
63 http://citeseer.ist.psu.edu/pearce04efficient.html
65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
67 http://citeseer.ist.psu.edu/heintze01ultrafast.html
69 There are three types of real constraint expressions, DEREF,
70 ADDRESSOF, and SCALAR. Each constraint expression consists
71 of a constraint type, a variable, and an offset.
73 SCALAR is a constraint expression type used to represent x, whether
74 it appears on the LHS or the RHS of a statement.
75 DEREF is a constraint expression type used to represent *x, whether
76 it appears on the LHS or the RHS of a statement.
77 ADDRESSOF is a constraint expression used to represent &x, whether
78 it appears on the LHS or the RHS of a statement.
80 Each pointer variable in the program is assigned an integer id, and
81 each field of a structure variable is assigned an integer id as well.
83 Structure variables are linked to their list of fields through a "next
84 field" in each variable that points to the next field in offset
86 Each variable for a structure field has
88 1. "size", that tells the size in bits of that field.
89 2. "fullsize, that tells the size in bits of the entire structure.
90 3. "offset", that tells the offset in bits from the beginning of the
91 structure to this field.
103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
108 In order to solve the system of set constraints, the following is
111 1. Each constraint variable x has a solution set associated with it,
114 2. Constraints are separated into direct, copy, and complex.
115 Direct constraints are ADDRESSOF constraints that require no extra
116 processing, such as P = &Q
117 Copy constraints are those of the form P = Q.
118 Complex constraints are all the constraints involving dereferences
119 and offsets (including offsetted copies).
121 3. All direct constraints of the form P = &Q are processed, such
122 that Q is added to Sol(P)
124 4. All complex constraints for a given constraint variable are stored in a
125 linked list attached to that variable's node.
127 5. A directed graph is built out of the copy constraints. Each
128 constraint variable is a node in the graph, and an edge from
129 Q to P is added for each copy constraint of the form P = Q
131 6. The graph is then walked, and solution sets are
132 propagated along the copy edges, such that an edge from Q to P
133 causes Sol(P) <- Sol(P) union Sol(Q).
135 7. As we visit each node, all complex constraints associated with
136 that node are processed by adding appropriate copy edges to the graph, or the
137 appropriate variables to the solution set.
139 8. The process of walking the graph is iterated until no solution
142 Prior to walking the graph in steps 6 and 7, We perform static
143 cycle elimination on the constraint graph, as well
144 as off-line variable substitution.
146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
147 on and turned into anything), but isn't. You can just see what offset
148 inside the pointed-to struct it's going to access.
150 TODO: Constant bounded arrays can be handled as if they were structs of the
151 same number of elements.
153 TODO: Modeling heap and incoming pointers becomes much better if we
154 add fields to them as we discover them, which we could do.
156 TODO: We could handle unions, but to be honest, it's probably not
157 worth the pain or slowdown. */
159 /* IPA-PTA optimizations possible.
161 When the indirect function called is ANYTHING we can add disambiguation
162 based on the function signatures (or simply the parameter count which
163 is the varinfo size). We also do not need to consider functions that
164 do not have their address taken.
166 The is_global_var bit which marks escape points is overly conservative
167 in IPA mode. Split it to is_escape_point and is_global_var - only
168 externally visible globals are escape points in IPA mode. This is
169 also needed to fix the pt_solution_includes_global predicate
170 (and thus ptr_deref_may_alias_global_p).
172 The way we introduce DECL_PT_UID to avoid fixing up all points-to
173 sets in the translation unit when we copy a DECL during inlining
174 pessimizes precision. The advantage is that the DECL_PT_UID keeps
175 compile-time and memory usage overhead low - the points-to sets
176 do not grow or get unshared as they would during a fixup phase.
177 An alternative solution is to delay IPA PTA until after all
178 inlining transformations have been applied.
180 The way we propagate clobber/use information isn't optimized.
181 It should use a new complex constraint that properly filters
182 out local variables of the callee (though that would make
183 the sets invalid after inlining). OTOH we might as well
184 admit defeat to WHOPR and simply do all the clobber/use analysis
185 and propagation after PTA finished but before we threw away
186 points-to information for memory variables. WHOPR and PTA
187 do not play along well anyway - the whole constraint solving
188 would need to be done in WPA phase and it will be very interesting
189 to apply the results to local SSA names during LTRANS phase.
191 We probably should compute a per-function unit-ESCAPE solution
192 propagating it simply like the clobber / uses solutions. The
193 solution can go alongside the non-IPA espaced solution and be
194 used to query which vars escape the unit through a function.
196 We never put function decls in points-to sets so we do not
197 keep the set of called functions for indirect calls.
199 And probably more. */
200 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct heapvar_map)))
201 htab_t heapvar_for_stmt;
203 static bool use_field_sensitive = true;
204 static int in_ipa_mode = 0;
206 /* Used for predecessor bitmaps. */
207 static bitmap_obstack predbitmap_obstack;
209 /* Used for points-to sets. */
210 static bitmap_obstack pta_obstack;
212 /* Used for oldsolution members of variables. */
213 static bitmap_obstack oldpta_obstack;
215 /* Used for per-solver-iteration bitmaps. */
216 static bitmap_obstack iteration_obstack;
218 static unsigned int create_variable_info_for (tree, const char *);
219 typedef struct constraint_graph *constraint_graph_t;
220 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
223 typedef struct constraint *constraint_t;
225 DEF_VEC_P(constraint_t);
226 DEF_VEC_ALLOC_P(constraint_t,heap);
228 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
230 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
232 static struct constraint_stats
234 unsigned int total_vars;
235 unsigned int nonpointer_vars;
236 unsigned int unified_vars_static;
237 unsigned int unified_vars_dynamic;
238 unsigned int iterations;
239 unsigned int num_edges;
240 unsigned int num_implicit_edges;
241 unsigned int points_to_sets_created;
246 /* ID of this variable */
249 /* True if this is a variable created by the constraint analysis, such as
250 heap variables and constraints we had to break up. */
251 unsigned int is_artificial_var : 1;
253 /* True if this is a special variable whose solution set should not be
255 unsigned int is_special_var : 1;
257 /* True for variables whose size is not known or variable. */
258 unsigned int is_unknown_size_var : 1;
260 /* True for (sub-)fields that represent a whole variable. */
261 unsigned int is_full_var : 1;
263 /* True if this is a heap variable. */
264 unsigned int is_heap_var : 1;
266 /* True if this is a variable tracking a restrict pointer source. */
267 unsigned int is_restrict_var : 1;
269 /* True if this field may contain pointers. */
270 unsigned int may_have_pointers : 1;
272 /* True if this field has only restrict qualified pointers. */
273 unsigned int only_restrict_pointers : 1;
275 /* True if this represents a global variable. */
276 unsigned int is_global_var : 1;
278 /* True if this represents a IPA function info. */
279 unsigned int is_fn_info : 1;
281 /* A link to the variable for the next field in this structure. */
282 struct variable_info *next;
284 /* Offset of this variable, in bits, from the base variable */
285 unsigned HOST_WIDE_INT offset;
287 /* Size of the variable, in bits. */
288 unsigned HOST_WIDE_INT size;
290 /* Full size of the base variable, in bits. */
291 unsigned HOST_WIDE_INT fullsize;
293 /* Name of this variable */
296 /* Tree that this variable is associated with. */
299 /* Points-to set for this variable. */
302 /* Old points-to set for this variable. */
305 typedef struct variable_info *varinfo_t;
307 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
308 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
309 unsigned HOST_WIDE_INT);
310 static varinfo_t lookup_vi_for_tree (tree);
312 /* Pool of variable info structures. */
313 static alloc_pool variable_info_pool;
315 DEF_VEC_P(varinfo_t);
317 DEF_VEC_ALLOC_P(varinfo_t, heap);
319 /* Table of variable info structures for constraint variables.
320 Indexed directly by variable info id. */
321 static VEC(varinfo_t,heap) *varmap;
323 /* Return the varmap element N */
325 static inline varinfo_t
326 get_varinfo (unsigned int n)
328 return VEC_index (varinfo_t, varmap, n);
331 /* Static IDs for the special variables. */
332 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
333 escaped_id = 3, nonlocal_id = 4,
334 storedanything_id = 5, integer_id = 6 };
336 struct GTY(()) heapvar_map {
338 unsigned HOST_WIDE_INT offset;
342 heapvar_map_eq (const void *p1, const void *p2)
344 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
345 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
346 return (h1->map.base.from == h2->map.base.from
347 && h1->offset == h2->offset);
351 heapvar_map_hash (struct heapvar_map *h)
353 return iterative_hash_host_wide_int (h->offset,
354 htab_hash_pointer (h->map.base.from));
357 /* Lookup a heap var for FROM, and return it if we find one. */
360 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
362 struct heapvar_map *h, in;
363 in.map.base.from = from;
365 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
366 heapvar_map_hash (&in));
372 /* Insert a mapping FROM->TO in the heap var for statement
376 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
378 struct heapvar_map *h;
381 h = ggc_alloc_heapvar_map ();
382 h->map.base.from = from;
384 h->map.hash = heapvar_map_hash (h);
386 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
387 gcc_assert (*loc == NULL);
388 *(struct heapvar_map **) loc = h;
391 /* Return a new variable info structure consisting for a variable
392 named NAME, and using constraint graph node NODE. Append it
393 to the vector of variable info structures. */
396 new_var_info (tree t, const char *name)
398 unsigned index = VEC_length (varinfo_t, varmap);
399 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
404 /* Vars without decl are artificial and do not have sub-variables. */
405 ret->is_artificial_var = (t == NULL_TREE);
406 ret->is_special_var = false;
407 ret->is_unknown_size_var = false;
408 ret->is_full_var = (t == NULL_TREE);
409 ret->is_heap_var = false;
410 ret->is_restrict_var = false;
411 ret->may_have_pointers = true;
412 ret->only_restrict_pointers = false;
413 ret->is_global_var = (t == NULL_TREE);
414 ret->is_fn_info = false;
416 ret->is_global_var = (is_global_var (t)
417 /* We have to treat even local register variables
419 || (TREE_CODE (t) == VAR_DECL
420 && DECL_HARD_REGISTER (t)));
421 ret->solution = BITMAP_ALLOC (&pta_obstack);
422 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
427 VEC_safe_push (varinfo_t, heap, varmap, ret);
433 /* A map mapping call statements to per-stmt variables for uses
434 and clobbers specific to the call. */
435 struct pointer_map_t *call_stmt_vars;
437 /* Lookup or create the variable for the call statement CALL. */
440 get_call_vi (gimple call)
445 slot_p = pointer_map_insert (call_stmt_vars, call);
447 return (varinfo_t) *slot_p;
449 vi = new_var_info (NULL_TREE, "CALLUSED");
453 vi->is_full_var = true;
455 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
459 vi2->is_full_var = true;
461 *slot_p = (void *) vi;
465 /* Lookup the variable for the call statement CALL representing
466 the uses. Returns NULL if there is nothing special about this call. */
469 lookup_call_use_vi (gimple call)
473 slot_p = pointer_map_contains (call_stmt_vars, call);
475 return (varinfo_t) *slot_p;
480 /* Lookup the variable for the call statement CALL representing
481 the clobbers. Returns NULL if there is nothing special about this call. */
484 lookup_call_clobber_vi (gimple call)
486 varinfo_t uses = lookup_call_use_vi (call);
493 /* Lookup or create the variable for the call statement CALL representing
497 get_call_use_vi (gimple call)
499 return get_call_vi (call);
502 /* Lookup or create the variable for the call statement CALL representing
505 static varinfo_t ATTRIBUTE_UNUSED
506 get_call_clobber_vi (gimple call)
508 return get_call_vi (call)->next;
512 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
514 /* An expression that appears in a constraint. */
516 struct constraint_expr
518 /* Constraint type. */
519 constraint_expr_type type;
521 /* Variable we are referring to in the constraint. */
524 /* Offset, in bits, of this constraint from the beginning of
525 variables it ends up referring to.
527 IOW, in a deref constraint, we would deref, get the result set,
528 then add OFFSET to each member. */
529 HOST_WIDE_INT offset;
532 /* Use 0x8000... as special unknown offset. */
533 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
535 typedef struct constraint_expr ce_s;
537 DEF_VEC_ALLOC_O(ce_s, heap);
538 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
539 static void get_constraint_for (tree, VEC(ce_s, heap) **);
540 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
541 static void do_deref (VEC (ce_s, heap) **);
543 /* Our set constraints are made up of two constraint expressions, one
546 As described in the introduction, our set constraints each represent an
547 operation between set valued variables.
551 struct constraint_expr lhs;
552 struct constraint_expr rhs;
555 /* List of constraints that we use to build the constraint graph from. */
557 static VEC(constraint_t,heap) *constraints;
558 static alloc_pool constraint_pool;
560 /* The constraint graph is represented as an array of bitmaps
561 containing successor nodes. */
563 struct constraint_graph
565 /* Size of this graph, which may be different than the number of
566 nodes in the variable map. */
569 /* Explicit successors of each node. */
572 /* Implicit predecessors of each node (Used for variable
574 bitmap *implicit_preds;
576 /* Explicit predecessors of each node (Used for variable substitution). */
579 /* Indirect cycle representatives, or -1 if the node has no indirect
581 int *indirect_cycles;
583 /* Representative node for a node. rep[a] == a unless the node has
587 /* Equivalence class representative for a label. This is used for
588 variable substitution. */
591 /* Pointer equivalence label for a node. All nodes with the same
592 pointer equivalence label can be unified together at some point
593 (either during constraint optimization or after the constraint
597 /* Pointer equivalence representative for a label. This is used to
598 handle nodes that are pointer equivalent but not location
599 equivalent. We can unite these once the addressof constraints
600 are transformed into initial points-to sets. */
603 /* Pointer equivalence label for each node, used during variable
605 unsigned int *pointer_label;
607 /* Location equivalence label for each node, used during location
608 equivalence finding. */
609 unsigned int *loc_label;
611 /* Pointed-by set for each node, used during location equivalence
612 finding. This is pointed-by rather than pointed-to, because it
613 is constructed using the predecessor graph. */
616 /* Points to sets for pointer equivalence. This is *not* the actual
617 points-to sets for nodes. */
620 /* Bitmap of nodes where the bit is set if the node is a direct
621 node. Used for variable substitution. */
622 sbitmap direct_nodes;
624 /* Bitmap of nodes where the bit is set if the node is address
625 taken. Used for variable substitution. */
626 bitmap address_taken;
628 /* Vector of complex constraints for each graph node. Complex
629 constraints are those involving dereferences or offsets that are
631 VEC(constraint_t,heap) **complex;
634 static constraint_graph_t graph;
636 /* During variable substitution and the offline version of indirect
637 cycle finding, we create nodes to represent dereferences and
638 address taken constraints. These represent where these start and
640 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
641 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
643 /* Return the representative node for NODE, if NODE has been unioned
645 This function performs path compression along the way to finding
646 the representative. */
649 find (unsigned int node)
651 gcc_assert (node < graph->size);
652 if (graph->rep[node] != node)
653 return graph->rep[node] = find (graph->rep[node]);
657 /* Union the TO and FROM nodes to the TO nodes.
658 Note that at some point in the future, we may want to do
659 union-by-rank, in which case we are going to have to return the
660 node we unified to. */
663 unite (unsigned int to, unsigned int from)
665 gcc_assert (to < graph->size && from < graph->size);
666 if (to != from && graph->rep[from] != to)
668 graph->rep[from] = to;
674 /* Create a new constraint consisting of LHS and RHS expressions. */
677 new_constraint (const struct constraint_expr lhs,
678 const struct constraint_expr rhs)
680 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
686 /* Print out constraint C to FILE. */
689 dump_constraint (FILE *file, constraint_t c)
691 if (c->lhs.type == ADDRESSOF)
693 else if (c->lhs.type == DEREF)
695 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
696 if (c->lhs.offset == UNKNOWN_OFFSET)
697 fprintf (file, " + UNKNOWN");
698 else if (c->lhs.offset != 0)
699 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
700 fprintf (file, " = ");
701 if (c->rhs.type == ADDRESSOF)
703 else if (c->rhs.type == DEREF)
705 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
706 if (c->rhs.offset == UNKNOWN_OFFSET)
707 fprintf (file, " + UNKNOWN");
708 else if (c->rhs.offset != 0)
709 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
710 fprintf (file, "\n");
714 void debug_constraint (constraint_t);
715 void debug_constraints (void);
716 void debug_constraint_graph (void);
717 void debug_solution_for_var (unsigned int);
718 void debug_sa_points_to_info (void);
720 /* Print out constraint C to stderr. */
723 debug_constraint (constraint_t c)
725 dump_constraint (stderr, c);
728 /* Print out all constraints to FILE */
731 dump_constraints (FILE *file, int from)
735 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
736 dump_constraint (file, c);
739 /* Print out all constraints to stderr. */
742 debug_constraints (void)
744 dump_constraints (stderr, 0);
747 /* Print out to FILE the edge in the constraint graph that is created by
748 constraint c. The edge may have a label, depending on the type of
749 constraint that it represents. If complex1, e.g: a = *b, then the label
750 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
751 complex with an offset, e.g: a = b + 8, then the label is "+".
752 Otherwise the edge has no label. */
755 dump_constraint_edge (FILE *file, constraint_t c)
757 if (c->rhs.type != ADDRESSOF)
759 const char *src = get_varinfo (c->rhs.var)->name;
760 const char *dst = get_varinfo (c->lhs.var)->name;
761 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
762 /* Due to preprocessing of constraints, instructions like *a = *b are
763 illegal; thus, we do not have to handle such cases. */
764 if (c->lhs.type == DEREF)
765 fprintf (file, " [ label=\"*=\" ] ;\n");
766 else if (c->rhs.type == DEREF)
767 fprintf (file, " [ label=\"=*\" ] ;\n");
770 /* We must check the case where the constraint is an offset.
771 In this case, it is treated as a complex constraint. */
772 if (c->rhs.offset != c->lhs.offset)
773 fprintf (file, " [ label=\"+\" ] ;\n");
775 fprintf (file, " ;\n");
780 /* Print the constraint graph in dot format. */
783 dump_constraint_graph (FILE *file)
785 unsigned int i=0, size;
788 /* Only print the graph if it has already been initialized: */
792 /* Print the constraints used to produce the constraint graph. The
793 constraints will be printed as comments in the dot file: */
794 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
795 dump_constraints (file, 0);
796 fprintf (file, "*/\n");
798 /* Prints the header of the dot file: */
799 fprintf (file, "\n\n// The constraint graph in dot format:\n");
800 fprintf (file, "strict digraph {\n");
801 fprintf (file, " node [\n shape = box\n ]\n");
802 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
803 fprintf (file, "\n // List of nodes in the constraint graph:\n");
805 /* The next lines print the nodes in the graph. In order to get the
806 number of nodes in the graph, we must choose the minimum between the
807 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
808 yet been initialized, then graph->size == 0, otherwise we must only
809 read nodes that have an entry in VEC (varinfo_t, varmap). */
810 size = VEC_length (varinfo_t, varmap);
811 size = size < graph->size ? size : graph->size;
812 for (i = 0; i < size; i++)
814 const char *name = get_varinfo (graph->rep[i])->name;
815 fprintf (file, " \"%s\" ;\n", name);
818 /* Go over the list of constraints printing the edges in the constraint
820 fprintf (file, "\n // The constraint edges:\n");
821 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
823 dump_constraint_edge (file, c);
825 /* Prints the tail of the dot file. By now, only the closing bracket. */
826 fprintf (file, "}\n\n\n");
829 /* Print out the constraint graph to stderr. */
832 debug_constraint_graph (void)
834 dump_constraint_graph (stderr);
839 The solver is a simple worklist solver, that works on the following
842 sbitmap changed_nodes = all zeroes;
844 For each node that is not already collapsed:
846 set bit in changed nodes
848 while (changed_count > 0)
850 compute topological ordering for constraint graph
852 find and collapse cycles in the constraint graph (updating
853 changed if necessary)
855 for each node (n) in the graph in topological order:
858 Process each complex constraint associated with the node,
859 updating changed if necessary.
861 For each outgoing edge from n, propagate the solution from n to
862 the destination of the edge, updating changed as necessary.
866 /* Return true if two constraint expressions A and B are equal. */
869 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
871 return a.type == b.type && a.var == b.var && a.offset == b.offset;
874 /* Return true if constraint expression A is less than constraint expression
875 B. This is just arbitrary, but consistent, in order to give them an
879 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
881 if (a.type == b.type)
884 return a.offset < b.offset;
886 return a.var < b.var;
889 return a.type < b.type;
892 /* Return true if constraint A is less than constraint B. This is just
893 arbitrary, but consistent, in order to give them an ordering. */
896 constraint_less (const constraint_t a, const constraint_t b)
898 if (constraint_expr_less (a->lhs, b->lhs))
900 else if (constraint_expr_less (b->lhs, a->lhs))
903 return constraint_expr_less (a->rhs, b->rhs);
906 /* Return true if two constraints A and B are equal. */
909 constraint_equal (struct constraint a, struct constraint b)
911 return constraint_expr_equal (a.lhs, b.lhs)
912 && constraint_expr_equal (a.rhs, b.rhs);
916 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
919 constraint_vec_find (VEC(constraint_t,heap) *vec,
920 struct constraint lookfor)
928 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
929 if (place >= VEC_length (constraint_t, vec))
931 found = VEC_index (constraint_t, vec, place);
932 if (!constraint_equal (*found, lookfor))
937 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
940 constraint_set_union (VEC(constraint_t,heap) **to,
941 VEC(constraint_t,heap) **from)
946 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
948 if (constraint_vec_find (*to, *c) == NULL)
950 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
952 VEC_safe_insert (constraint_t, heap, *to, place, c);
957 /* Expands the solution in SET to all sub-fields of variables included.
958 Union the expanded result into RESULT. */
961 solution_set_expand (bitmap result, bitmap set)
967 /* In a first pass record all variables we need to add all
968 sub-fields off. This avoids quadratic behavior. */
969 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
971 varinfo_t v = get_varinfo (j);
972 if (v->is_artificial_var
975 v = lookup_vi_for_tree (v->decl);
977 vars = BITMAP_ALLOC (NULL);
978 bitmap_set_bit (vars, v->id);
981 /* In the second pass now do the addition to the solution and
982 to speed up solving add it to the delta as well. */
985 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
987 varinfo_t v = get_varinfo (j);
988 for (; v != NULL; v = v->next)
989 bitmap_set_bit (result, v->id);
995 /* Take a solution set SET, add OFFSET to each member of the set, and
996 overwrite SET with the result when done. */
999 solution_set_add (bitmap set, HOST_WIDE_INT offset)
1001 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1005 /* If the offset is unknown we have to expand the solution to
1007 if (offset == UNKNOWN_OFFSET)
1009 solution_set_expand (set, set);
1013 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1015 varinfo_t vi = get_varinfo (i);
1017 /* If this is a variable with just one field just set its bit
1019 if (vi->is_artificial_var
1020 || vi->is_unknown_size_var
1022 bitmap_set_bit (result, i);
1025 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1027 /* If the offset makes the pointer point to before the
1028 variable use offset zero for the field lookup. */
1030 && fieldoffset > vi->offset)
1034 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1036 bitmap_set_bit (result, vi->id);
1037 /* If the result is not exactly at fieldoffset include the next
1038 field as well. See get_constraint_for_ptr_offset for more
1040 if (vi->offset != fieldoffset
1041 && vi->next != NULL)
1042 bitmap_set_bit (result, vi->next->id);
1046 bitmap_copy (set, result);
1047 BITMAP_FREE (result);
1050 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1054 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1057 return bitmap_ior_into (to, from);
1063 tmp = BITMAP_ALLOC (&iteration_obstack);
1064 bitmap_copy (tmp, from);
1065 solution_set_add (tmp, inc);
1066 res = bitmap_ior_into (to, tmp);
1072 /* Insert constraint C into the list of complex constraints for graph
1076 insert_into_complex (constraint_graph_t graph,
1077 unsigned int var, constraint_t c)
1079 VEC (constraint_t, heap) *complex = graph->complex[var];
1080 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1083 /* Only insert constraints that do not already exist. */
1084 if (place >= VEC_length (constraint_t, complex)
1085 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1086 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1090 /* Condense two variable nodes into a single variable node, by moving
1091 all associated info from SRC to TO. */
1094 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1100 gcc_assert (find (from) == to);
1102 /* Move all complex constraints from src node into to node */
1103 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1105 /* In complex constraints for node src, we may have either
1106 a = *src, and *src = a, or an offseted constraint which are
1107 always added to the rhs node's constraints. */
1109 if (c->rhs.type == DEREF)
1111 else if (c->lhs.type == DEREF)
1116 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1117 VEC_free (constraint_t, heap, graph->complex[from]);
1118 graph->complex[from] = NULL;
1122 /* Remove edges involving NODE from GRAPH. */
1125 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1127 if (graph->succs[node])
1128 BITMAP_FREE (graph->succs[node]);
1131 /* Merge GRAPH nodes FROM and TO into node TO. */
1134 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1137 if (graph->indirect_cycles[from] != -1)
1139 /* If we have indirect cycles with the from node, and we have
1140 none on the to node, the to node has indirect cycles from the
1141 from node now that they are unified.
1142 If indirect cycles exist on both, unify the nodes that they
1143 are in a cycle with, since we know they are in a cycle with
1145 if (graph->indirect_cycles[to] == -1)
1146 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1149 /* Merge all the successor edges. */
1150 if (graph->succs[from])
1152 if (!graph->succs[to])
1153 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1154 bitmap_ior_into (graph->succs[to],
1155 graph->succs[from]);
1158 clear_edges_for_node (graph, from);
1162 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1163 it doesn't exist in the graph already. */
1166 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1172 if (!graph->implicit_preds[to])
1173 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1175 if (bitmap_set_bit (graph->implicit_preds[to], from))
1176 stats.num_implicit_edges++;
1179 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1180 it doesn't exist in the graph already.
1181 Return false if the edge already existed, true otherwise. */
1184 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1187 if (!graph->preds[to])
1188 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1189 bitmap_set_bit (graph->preds[to], from);
1192 /* Add a graph edge to GRAPH, going from FROM to TO if
1193 it doesn't exist in the graph already.
1194 Return false if the edge already existed, true otherwise. */
1197 add_graph_edge (constraint_graph_t graph, unsigned int to,
1208 if (!graph->succs[from])
1209 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1210 if (bitmap_set_bit (graph->succs[from], to))
1213 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1221 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1224 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1227 return (graph->succs[dest]
1228 && bitmap_bit_p (graph->succs[dest], src));
1231 /* Initialize the constraint graph structure to contain SIZE nodes. */
1234 init_graph (unsigned int size)
1238 graph = XCNEW (struct constraint_graph);
1240 graph->succs = XCNEWVEC (bitmap, graph->size);
1241 graph->indirect_cycles = XNEWVEC (int, graph->size);
1242 graph->rep = XNEWVEC (unsigned int, graph->size);
1243 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1244 graph->pe = XCNEWVEC (unsigned int, graph->size);
1245 graph->pe_rep = XNEWVEC (int, graph->size);
1247 for (j = 0; j < graph->size; j++)
1250 graph->pe_rep[j] = -1;
1251 graph->indirect_cycles[j] = -1;
1255 /* Build the constraint graph, adding only predecessor edges right now. */
1258 build_pred_graph (void)
1264 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1265 graph->preds = XCNEWVEC (bitmap, graph->size);
1266 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1267 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1268 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1269 graph->points_to = XCNEWVEC (bitmap, graph->size);
1270 graph->eq_rep = XNEWVEC (int, graph->size);
1271 graph->direct_nodes = sbitmap_alloc (graph->size);
1272 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1273 sbitmap_zero (graph->direct_nodes);
1275 for (j = 0; j < FIRST_REF_NODE; j++)
1277 if (!get_varinfo (j)->is_special_var)
1278 SET_BIT (graph->direct_nodes, j);
1281 for (j = 0; j < graph->size; j++)
1282 graph->eq_rep[j] = -1;
1284 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1285 graph->indirect_cycles[j] = -1;
1287 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1289 struct constraint_expr lhs = c->lhs;
1290 struct constraint_expr rhs = c->rhs;
1291 unsigned int lhsvar = lhs.var;
1292 unsigned int rhsvar = rhs.var;
1294 if (lhs.type == DEREF)
1297 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1298 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1300 else if (rhs.type == DEREF)
1303 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1304 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1306 RESET_BIT (graph->direct_nodes, lhsvar);
1308 else if (rhs.type == ADDRESSOF)
1313 if (graph->points_to[lhsvar] == NULL)
1314 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1315 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1317 if (graph->pointed_by[rhsvar] == NULL)
1318 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1319 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1321 /* Implicitly, *x = y */
1322 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1324 /* All related variables are no longer direct nodes. */
1325 RESET_BIT (graph->direct_nodes, rhsvar);
1326 v = get_varinfo (rhsvar);
1327 if (!v->is_full_var)
1329 v = lookup_vi_for_tree (v->decl);
1332 RESET_BIT (graph->direct_nodes, v->id);
1337 bitmap_set_bit (graph->address_taken, rhsvar);
1339 else if (lhsvar > anything_id
1340 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1343 add_pred_graph_edge (graph, lhsvar, rhsvar);
1344 /* Implicitly, *x = *y */
1345 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1346 FIRST_REF_NODE + rhsvar);
1348 else if (lhs.offset != 0 || rhs.offset != 0)
1350 if (rhs.offset != 0)
1351 RESET_BIT (graph->direct_nodes, lhs.var);
1352 else if (lhs.offset != 0)
1353 RESET_BIT (graph->direct_nodes, rhs.var);
1358 /* Build the constraint graph, adding successor edges. */
1361 build_succ_graph (void)
1366 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1368 struct constraint_expr lhs;
1369 struct constraint_expr rhs;
1370 unsigned int lhsvar;
1371 unsigned int rhsvar;
1378 lhsvar = find (lhs.var);
1379 rhsvar = find (rhs.var);
1381 if (lhs.type == DEREF)
1383 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1384 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1386 else if (rhs.type == DEREF)
1388 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1389 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1391 else if (rhs.type == ADDRESSOF)
1394 gcc_assert (find (rhs.var) == rhs.var);
1395 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1397 else if (lhsvar > anything_id
1398 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1400 add_graph_edge (graph, lhsvar, rhsvar);
1404 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1405 receive pointers. */
1406 t = find (storedanything_id);
1407 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1409 if (!TEST_BIT (graph->direct_nodes, i)
1410 && get_varinfo (i)->may_have_pointers)
1411 add_graph_edge (graph, find (i), t);
1414 /* Everything stored to ANYTHING also potentially escapes. */
1415 add_graph_edge (graph, find (escaped_id), t);
1419 /* Changed variables on the last iteration. */
1420 static unsigned int changed_count;
1421 static sbitmap changed;
1423 /* Strongly Connected Component visitation info. */
1430 unsigned int *node_mapping;
1432 VEC(unsigned,heap) *scc_stack;
1436 /* Recursive routine to find strongly connected components in GRAPH.
1437 SI is the SCC info to store the information in, and N is the id of current
1438 graph node we are processing.
1440 This is Tarjan's strongly connected component finding algorithm, as
1441 modified by Nuutila to keep only non-root nodes on the stack.
1442 The algorithm can be found in "On finding the strongly connected
1443 connected components in a directed graph" by Esko Nuutila and Eljas
1444 Soisalon-Soininen, in Information Processing Letters volume 49,
1445 number 1, pages 9-14. */
1448 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1452 unsigned int my_dfs;
1454 SET_BIT (si->visited, n);
1455 si->dfs[n] = si->current_index ++;
1456 my_dfs = si->dfs[n];
1458 /* Visit all the successors. */
1459 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1463 if (i > LAST_REF_NODE)
1467 if (TEST_BIT (si->deleted, w))
1470 if (!TEST_BIT (si->visited, w))
1471 scc_visit (graph, si, w);
1473 unsigned int t = find (w);
1474 unsigned int nnode = find (n);
1475 gcc_assert (nnode == n);
1477 if (si->dfs[t] < si->dfs[nnode])
1478 si->dfs[n] = si->dfs[t];
1482 /* See if any components have been identified. */
1483 if (si->dfs[n] == my_dfs)
1485 if (VEC_length (unsigned, si->scc_stack) > 0
1486 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1488 bitmap scc = BITMAP_ALLOC (NULL);
1489 unsigned int lowest_node;
1492 bitmap_set_bit (scc, n);
1494 while (VEC_length (unsigned, si->scc_stack) != 0
1495 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1497 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1499 bitmap_set_bit (scc, w);
1502 lowest_node = bitmap_first_set_bit (scc);
1503 gcc_assert (lowest_node < FIRST_REF_NODE);
1505 /* Collapse the SCC nodes into a single node, and mark the
1507 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1509 if (i < FIRST_REF_NODE)
1511 if (unite (lowest_node, i))
1512 unify_nodes (graph, lowest_node, i, false);
1516 unite (lowest_node, i);
1517 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1521 SET_BIT (si->deleted, n);
1524 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1527 /* Unify node FROM into node TO, updating the changed count if
1528 necessary when UPDATE_CHANGED is true. */
1531 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1532 bool update_changed)
1535 gcc_assert (to != from && find (to) == to);
1536 if (dump_file && (dump_flags & TDF_DETAILS))
1537 fprintf (dump_file, "Unifying %s to %s\n",
1538 get_varinfo (from)->name,
1539 get_varinfo (to)->name);
1542 stats.unified_vars_dynamic++;
1544 stats.unified_vars_static++;
1546 merge_graph_nodes (graph, to, from);
1547 merge_node_constraints (graph, to, from);
1549 /* Mark TO as changed if FROM was changed. If TO was already marked
1550 as changed, decrease the changed count. */
1552 if (update_changed && TEST_BIT (changed, from))
1554 RESET_BIT (changed, from);
1555 if (!TEST_BIT (changed, to))
1556 SET_BIT (changed, to);
1559 gcc_assert (changed_count > 0);
1563 if (get_varinfo (from)->solution)
1565 /* If the solution changes because of the merging, we need to mark
1566 the variable as changed. */
1567 if (bitmap_ior_into (get_varinfo (to)->solution,
1568 get_varinfo (from)->solution))
1570 if (update_changed && !TEST_BIT (changed, to))
1572 SET_BIT (changed, to);
1577 BITMAP_FREE (get_varinfo (from)->solution);
1578 BITMAP_FREE (get_varinfo (from)->oldsolution);
1580 if (stats.iterations > 0)
1582 BITMAP_FREE (get_varinfo (to)->oldsolution);
1583 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1586 if (valid_graph_edge (graph, to, to))
1588 if (graph->succs[to])
1589 bitmap_clear_bit (graph->succs[to], to);
1593 /* Information needed to compute the topological ordering of a graph. */
1597 /* sbitmap of visited nodes. */
1599 /* Array that stores the topological order of the graph, *in
1601 VEC(unsigned,heap) *topo_order;
1605 /* Initialize and return a topological info structure. */
1607 static struct topo_info *
1608 init_topo_info (void)
1610 size_t size = graph->size;
1611 struct topo_info *ti = XNEW (struct topo_info);
1612 ti->visited = sbitmap_alloc (size);
1613 sbitmap_zero (ti->visited);
1614 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1619 /* Free the topological sort info pointed to by TI. */
1622 free_topo_info (struct topo_info *ti)
1624 sbitmap_free (ti->visited);
1625 VEC_free (unsigned, heap, ti->topo_order);
1629 /* Visit the graph in topological order, and store the order in the
1630 topo_info structure. */
1633 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1639 SET_BIT (ti->visited, n);
1641 if (graph->succs[n])
1642 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1644 if (!TEST_BIT (ti->visited, j))
1645 topo_visit (graph, ti, j);
1648 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1651 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1652 starting solution for y. */
1655 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1658 unsigned int lhs = c->lhs.var;
1660 bitmap sol = get_varinfo (lhs)->solution;
1663 HOST_WIDE_INT roffset = c->rhs.offset;
1665 /* Our IL does not allow this. */
1666 gcc_assert (c->lhs.offset == 0);
1668 /* If the solution of Y contains anything it is good enough to transfer
1670 if (bitmap_bit_p (delta, anything_id))
1672 flag |= bitmap_set_bit (sol, anything_id);
1676 /* If we do not know at with offset the rhs is dereferenced compute
1677 the reachability set of DELTA, conservatively assuming it is
1678 dereferenced at all valid offsets. */
1679 if (roffset == UNKNOWN_OFFSET)
1681 solution_set_expand (delta, delta);
1682 /* No further offset processing is necessary. */
1686 /* For each variable j in delta (Sol(y)), add
1687 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1688 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1690 varinfo_t v = get_varinfo (j);
1691 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1695 fieldoffset = v->offset;
1696 else if (roffset != 0)
1697 v = first_vi_for_offset (v, fieldoffset);
1698 /* If the access is outside of the variable we can ignore it. */
1706 /* Adding edges from the special vars is pointless.
1707 They don't have sets that can change. */
1708 if (get_varinfo (t)->is_special_var)
1709 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1710 /* Merging the solution from ESCAPED needlessly increases
1711 the set. Use ESCAPED as representative instead. */
1712 else if (v->id == escaped_id)
1713 flag |= bitmap_set_bit (sol, escaped_id);
1714 else if (v->may_have_pointers
1715 && add_graph_edge (graph, lhs, t))
1716 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1718 /* If the variable is not exactly at the requested offset
1719 we have to include the next one. */
1720 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1725 fieldoffset = v->offset;
1731 /* If the LHS solution changed, mark the var as changed. */
1734 get_varinfo (lhs)->solution = sol;
1735 if (!TEST_BIT (changed, lhs))
1737 SET_BIT (changed, lhs);
1743 /* Process a constraint C that represents *(x + off) = y using DELTA
1744 as the starting solution for x. */
1747 do_ds_constraint (constraint_t c, bitmap delta)
1749 unsigned int rhs = c->rhs.var;
1750 bitmap sol = get_varinfo (rhs)->solution;
1753 HOST_WIDE_INT loff = c->lhs.offset;
1754 bool escaped_p = false;
1756 /* Our IL does not allow this. */
1757 gcc_assert (c->rhs.offset == 0);
1759 /* If the solution of y contains ANYTHING simply use the ANYTHING
1760 solution. This avoids needlessly increasing the points-to sets. */
1761 if (bitmap_bit_p (sol, anything_id))
1762 sol = get_varinfo (find (anything_id))->solution;
1764 /* If the solution for x contains ANYTHING we have to merge the
1765 solution of y into all pointer variables which we do via
1767 if (bitmap_bit_p (delta, anything_id))
1769 unsigned t = find (storedanything_id);
1770 if (add_graph_edge (graph, t, rhs))
1772 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1774 if (!TEST_BIT (changed, t))
1776 SET_BIT (changed, t);
1784 /* If we do not know at with offset the rhs is dereferenced compute
1785 the reachability set of DELTA, conservatively assuming it is
1786 dereferenced at all valid offsets. */
1787 if (loff == UNKNOWN_OFFSET)
1789 solution_set_expand (delta, delta);
1793 /* For each member j of delta (Sol(x)), add an edge from y to j and
1794 union Sol(y) into Sol(j) */
1795 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1797 varinfo_t v = get_varinfo (j);
1799 HOST_WIDE_INT fieldoffset = v->offset + loff;
1802 fieldoffset = v->offset;
1804 v = first_vi_for_offset (v, fieldoffset);
1805 /* If the access is outside of the variable we can ignore it. */
1811 if (v->may_have_pointers)
1813 /* If v is a global variable then this is an escape point. */
1814 if (v->is_global_var
1817 t = find (escaped_id);
1818 if (add_graph_edge (graph, t, rhs)
1819 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1820 && !TEST_BIT (changed, t))
1822 SET_BIT (changed, t);
1825 /* Enough to let rhs escape once. */
1829 if (v->is_special_var)
1833 if (add_graph_edge (graph, t, rhs)
1834 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1835 && !TEST_BIT (changed, t))
1837 SET_BIT (changed, t);
1842 /* If the variable is not exactly at the requested offset
1843 we have to include the next one. */
1844 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1849 fieldoffset = v->offset;
1855 /* Handle a non-simple (simple meaning requires no iteration),
1856 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1859 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1861 if (c->lhs.type == DEREF)
1863 if (c->rhs.type == ADDRESSOF)
1870 do_ds_constraint (c, delta);
1873 else if (c->rhs.type == DEREF)
1876 if (!(get_varinfo (c->lhs.var)->is_special_var))
1877 do_sd_constraint (graph, c, delta);
1885 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1886 solution = get_varinfo (c->rhs.var)->solution;
1887 tmp = get_varinfo (c->lhs.var)->solution;
1889 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1893 get_varinfo (c->lhs.var)->solution = tmp;
1894 if (!TEST_BIT (changed, c->lhs.var))
1896 SET_BIT (changed, c->lhs.var);
1903 /* Initialize and return a new SCC info structure. */
1905 static struct scc_info *
1906 init_scc_info (size_t size)
1908 struct scc_info *si = XNEW (struct scc_info);
1911 si->current_index = 0;
1912 si->visited = sbitmap_alloc (size);
1913 sbitmap_zero (si->visited);
1914 si->deleted = sbitmap_alloc (size);
1915 sbitmap_zero (si->deleted);
1916 si->node_mapping = XNEWVEC (unsigned int, size);
1917 si->dfs = XCNEWVEC (unsigned int, size);
1919 for (i = 0; i < size; i++)
1920 si->node_mapping[i] = i;
1922 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1926 /* Free an SCC info structure pointed to by SI */
1929 free_scc_info (struct scc_info *si)
1931 sbitmap_free (si->visited);
1932 sbitmap_free (si->deleted);
1933 free (si->node_mapping);
1935 VEC_free (unsigned, heap, si->scc_stack);
1940 /* Find indirect cycles in GRAPH that occur, using strongly connected
1941 components, and note them in the indirect cycles map.
1943 This technique comes from Ben Hardekopf and Calvin Lin,
1944 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1945 Lines of Code", submitted to PLDI 2007. */
1948 find_indirect_cycles (constraint_graph_t graph)
1951 unsigned int size = graph->size;
1952 struct scc_info *si = init_scc_info (size);
1954 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1955 if (!TEST_BIT (si->visited, i) && find (i) == i)
1956 scc_visit (graph, si, i);
1961 /* Compute a topological ordering for GRAPH, and store the result in the
1962 topo_info structure TI. */
1965 compute_topo_order (constraint_graph_t graph,
1966 struct topo_info *ti)
1969 unsigned int size = graph->size;
1971 for (i = 0; i != size; ++i)
1972 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1973 topo_visit (graph, ti, i);
1976 /* Structure used to for hash value numbering of pointer equivalence
1979 typedef struct equiv_class_label
1982 unsigned int equivalence_class;
1984 } *equiv_class_label_t;
1985 typedef const struct equiv_class_label *const_equiv_class_label_t;
1987 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1989 static htab_t pointer_equiv_class_table;
1991 /* A hashtable for mapping a bitmap of labels->location equivalence
1993 static htab_t location_equiv_class_table;
1995 /* Hash function for a equiv_class_label_t */
1998 equiv_class_label_hash (const void *p)
2000 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
2001 return ecl->hashcode;
2004 /* Equality function for two equiv_class_label_t's. */
2007 equiv_class_label_eq (const void *p1, const void *p2)
2009 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2010 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2011 return (eql1->hashcode == eql2->hashcode
2012 && bitmap_equal_p (eql1->labels, eql2->labels));
2015 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2019 equiv_class_lookup (htab_t table, bitmap labels)
2022 struct equiv_class_label ecl;
2024 ecl.labels = labels;
2025 ecl.hashcode = bitmap_hash (labels);
2027 slot = htab_find_slot_with_hash (table, &ecl,
2028 ecl.hashcode, NO_INSERT);
2032 return ((equiv_class_label_t) *slot)->equivalence_class;
2036 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2040 equiv_class_add (htab_t table, unsigned int equivalence_class,
2044 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2046 ecl->labels = labels;
2047 ecl->equivalence_class = equivalence_class;
2048 ecl->hashcode = bitmap_hash (labels);
2050 slot = htab_find_slot_with_hash (table, ecl,
2051 ecl->hashcode, INSERT);
2052 gcc_assert (!*slot);
2053 *slot = (void *) ecl;
2056 /* Perform offline variable substitution.
2058 This is a worst case quadratic time way of identifying variables
2059 that must have equivalent points-to sets, including those caused by
2060 static cycles, and single entry subgraphs, in the constraint graph.
2062 The technique is described in "Exploiting Pointer and Location
2063 Equivalence to Optimize Pointer Analysis. In the 14th International
2064 Static Analysis Symposium (SAS), August 2007." It is known as the
2065 "HU" algorithm, and is equivalent to value numbering the collapsed
2066 constraint graph including evaluating unions.
2068 The general method of finding equivalence classes is as follows:
2069 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2070 Initialize all non-REF nodes to be direct nodes.
2071 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2073 For each constraint containing the dereference, we also do the same
2076 We then compute SCC's in the graph and unify nodes in the same SCC,
2079 For each non-collapsed node x:
2080 Visit all unvisited explicit incoming edges.
2081 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2083 Lookup the equivalence class for pts(x).
2084 If we found one, equivalence_class(x) = found class.
2085 Otherwise, equivalence_class(x) = new class, and new_class is
2086 added to the lookup table.
2088 All direct nodes with the same equivalence class can be replaced
2089 with a single representative node.
2090 All unlabeled nodes (label == 0) are not pointers and all edges
2091 involving them can be eliminated.
2092 We perform these optimizations during rewrite_constraints
2094 In addition to pointer equivalence class finding, we also perform
2095 location equivalence class finding. This is the set of variables
2096 that always appear together in points-to sets. We use this to
2097 compress the size of the points-to sets. */
2099 /* Current maximum pointer equivalence class id. */
2100 static int pointer_equiv_class;
2102 /* Current maximum location equivalence class id. */
2103 static int location_equiv_class;
2105 /* Recursive routine to find strongly connected components in GRAPH,
2106 and label it's nodes with DFS numbers. */
2109 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2113 unsigned int my_dfs;
2115 gcc_assert (si->node_mapping[n] == n);
2116 SET_BIT (si->visited, n);
2117 si->dfs[n] = si->current_index ++;
2118 my_dfs = si->dfs[n];
2120 /* Visit all the successors. */
2121 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2123 unsigned int w = si->node_mapping[i];
2125 if (TEST_BIT (si->deleted, w))
2128 if (!TEST_BIT (si->visited, w))
2129 condense_visit (graph, si, w);
2131 unsigned int t = si->node_mapping[w];
2132 unsigned int nnode = si->node_mapping[n];
2133 gcc_assert (nnode == n);
2135 if (si->dfs[t] < si->dfs[nnode])
2136 si->dfs[n] = si->dfs[t];
2140 /* Visit all the implicit predecessors. */
2141 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2143 unsigned int w = si->node_mapping[i];
2145 if (TEST_BIT (si->deleted, w))
2148 if (!TEST_BIT (si->visited, w))
2149 condense_visit (graph, si, w);
2151 unsigned int t = si->node_mapping[w];
2152 unsigned int nnode = si->node_mapping[n];
2153 gcc_assert (nnode == n);
2155 if (si->dfs[t] < si->dfs[nnode])
2156 si->dfs[n] = si->dfs[t];
2160 /* See if any components have been identified. */
2161 if (si->dfs[n] == my_dfs)
2163 while (VEC_length (unsigned, si->scc_stack) != 0
2164 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2166 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2167 si->node_mapping[w] = n;
2169 if (!TEST_BIT (graph->direct_nodes, w))
2170 RESET_BIT (graph->direct_nodes, n);
2172 /* Unify our nodes. */
2173 if (graph->preds[w])
2175 if (!graph->preds[n])
2176 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2177 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2179 if (graph->implicit_preds[w])
2181 if (!graph->implicit_preds[n])
2182 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2183 bitmap_ior_into (graph->implicit_preds[n],
2184 graph->implicit_preds[w]);
2186 if (graph->points_to[w])
2188 if (!graph->points_to[n])
2189 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2190 bitmap_ior_into (graph->points_to[n],
2191 graph->points_to[w]);
2194 SET_BIT (si->deleted, n);
2197 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2200 /* Label pointer equivalences. */
2203 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2207 SET_BIT (si->visited, n);
2209 if (!graph->points_to[n])
2210 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2212 /* Label and union our incoming edges's points to sets. */
2213 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2215 unsigned int w = si->node_mapping[i];
2216 if (!TEST_BIT (si->visited, w))
2217 label_visit (graph, si, w);
2219 /* Skip unused edges */
2220 if (w == n || graph->pointer_label[w] == 0)
2223 if (graph->points_to[w])
2224 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2226 /* Indirect nodes get fresh variables. */
2227 if (!TEST_BIT (graph->direct_nodes, n))
2228 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2230 if (!bitmap_empty_p (graph->points_to[n]))
2232 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2233 graph->points_to[n]);
2236 label = pointer_equiv_class++;
2237 equiv_class_add (pointer_equiv_class_table,
2238 label, graph->points_to[n]);
2240 graph->pointer_label[n] = label;
2244 /* Perform offline variable substitution, discovering equivalence
2245 classes, and eliminating non-pointer variables. */
2247 static struct scc_info *
2248 perform_var_substitution (constraint_graph_t graph)
2251 unsigned int size = graph->size;
2252 struct scc_info *si = init_scc_info (size);
2254 bitmap_obstack_initialize (&iteration_obstack);
2255 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2256 equiv_class_label_eq, free);
2257 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2258 equiv_class_label_eq, free);
2259 pointer_equiv_class = 1;
2260 location_equiv_class = 1;
2262 /* Condense the nodes, which means to find SCC's, count incoming
2263 predecessors, and unite nodes in SCC's. */
2264 for (i = 0; i < FIRST_REF_NODE; i++)
2265 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2266 condense_visit (graph, si, si->node_mapping[i]);
2268 sbitmap_zero (si->visited);
2269 /* Actually the label the nodes for pointer equivalences */
2270 for (i = 0; i < FIRST_REF_NODE; i++)
2271 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2272 label_visit (graph, si, si->node_mapping[i]);
2274 /* Calculate location equivalence labels. */
2275 for (i = 0; i < FIRST_REF_NODE; i++)
2282 if (!graph->pointed_by[i])
2284 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2286 /* Translate the pointed-by mapping for pointer equivalence
2288 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2290 bitmap_set_bit (pointed_by,
2291 graph->pointer_label[si->node_mapping[j]]);
2293 /* The original pointed_by is now dead. */
2294 BITMAP_FREE (graph->pointed_by[i]);
2296 /* Look up the location equivalence label if one exists, or make
2298 label = equiv_class_lookup (location_equiv_class_table,
2302 label = location_equiv_class++;
2303 equiv_class_add (location_equiv_class_table,
2308 if (dump_file && (dump_flags & TDF_DETAILS))
2309 fprintf (dump_file, "Found location equivalence for node %s\n",
2310 get_varinfo (i)->name);
2311 BITMAP_FREE (pointed_by);
2313 graph->loc_label[i] = label;
2317 if (dump_file && (dump_flags & TDF_DETAILS))
2318 for (i = 0; i < FIRST_REF_NODE; i++)
2320 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2322 "Equivalence classes for %s node id %d:%s are pointer: %d"
2324 direct_node ? "Direct node" : "Indirect node", i,
2325 get_varinfo (i)->name,
2326 graph->pointer_label[si->node_mapping[i]],
2327 graph->loc_label[si->node_mapping[i]]);
2330 /* Quickly eliminate our non-pointer variables. */
2332 for (i = 0; i < FIRST_REF_NODE; i++)
2334 unsigned int node = si->node_mapping[i];
2336 if (graph->pointer_label[node] == 0)
2338 if (dump_file && (dump_flags & TDF_DETAILS))
2340 "%s is a non-pointer variable, eliminating edges.\n",
2341 get_varinfo (node)->name);
2342 stats.nonpointer_vars++;
2343 clear_edges_for_node (graph, node);
2350 /* Free information that was only necessary for variable
2354 free_var_substitution_info (struct scc_info *si)
2357 free (graph->pointer_label);
2358 free (graph->loc_label);
2359 free (graph->pointed_by);
2360 free (graph->points_to);
2361 free (graph->eq_rep);
2362 sbitmap_free (graph->direct_nodes);
2363 htab_delete (pointer_equiv_class_table);
2364 htab_delete (location_equiv_class_table);
2365 bitmap_obstack_release (&iteration_obstack);
2368 /* Return an existing node that is equivalent to NODE, which has
2369 equivalence class LABEL, if one exists. Return NODE otherwise. */
2372 find_equivalent_node (constraint_graph_t graph,
2373 unsigned int node, unsigned int label)
2375 /* If the address version of this variable is unused, we can
2376 substitute it for anything else with the same label.
2377 Otherwise, we know the pointers are equivalent, but not the
2378 locations, and we can unite them later. */
2380 if (!bitmap_bit_p (graph->address_taken, node))
2382 gcc_assert (label < graph->size);
2384 if (graph->eq_rep[label] != -1)
2386 /* Unify the two variables since we know they are equivalent. */
2387 if (unite (graph->eq_rep[label], node))
2388 unify_nodes (graph, graph->eq_rep[label], node, false);
2389 return graph->eq_rep[label];
2393 graph->eq_rep[label] = node;
2394 graph->pe_rep[label] = node;
2399 gcc_assert (label < graph->size);
2400 graph->pe[node] = label;
2401 if (graph->pe_rep[label] == -1)
2402 graph->pe_rep[label] = node;
2408 /* Unite pointer equivalent but not location equivalent nodes in
2409 GRAPH. This may only be performed once variable substitution is
2413 unite_pointer_equivalences (constraint_graph_t graph)
2417 /* Go through the pointer equivalences and unite them to their
2418 representative, if they aren't already. */
2419 for (i = 0; i < FIRST_REF_NODE; i++)
2421 unsigned int label = graph->pe[i];
2424 int label_rep = graph->pe_rep[label];
2426 if (label_rep == -1)
2429 label_rep = find (label_rep);
2430 if (label_rep >= 0 && unite (label_rep, find (i)))
2431 unify_nodes (graph, label_rep, i, false);
2436 /* Move complex constraints to the GRAPH nodes they belong to. */
2439 move_complex_constraints (constraint_graph_t graph)
2444 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2448 struct constraint_expr lhs = c->lhs;
2449 struct constraint_expr rhs = c->rhs;
2451 if (lhs.type == DEREF)
2453 insert_into_complex (graph, lhs.var, c);
2455 else if (rhs.type == DEREF)
2457 if (!(get_varinfo (lhs.var)->is_special_var))
2458 insert_into_complex (graph, rhs.var, c);
2460 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2461 && (lhs.offset != 0 || rhs.offset != 0))
2463 insert_into_complex (graph, rhs.var, c);
2470 /* Optimize and rewrite complex constraints while performing
2471 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2472 result of perform_variable_substitution. */
2475 rewrite_constraints (constraint_graph_t graph,
2476 struct scc_info *si)
2482 for (j = 0; j < graph->size; j++)
2483 gcc_assert (find (j) == j);
2485 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2487 struct constraint_expr lhs = c->lhs;
2488 struct constraint_expr rhs = c->rhs;
2489 unsigned int lhsvar = find (lhs.var);
2490 unsigned int rhsvar = find (rhs.var);
2491 unsigned int lhsnode, rhsnode;
2492 unsigned int lhslabel, rhslabel;
2494 lhsnode = si->node_mapping[lhsvar];
2495 rhsnode = si->node_mapping[rhsvar];
2496 lhslabel = graph->pointer_label[lhsnode];
2497 rhslabel = graph->pointer_label[rhsnode];
2499 /* See if it is really a non-pointer variable, and if so, ignore
2503 if (dump_file && (dump_flags & TDF_DETAILS))
2506 fprintf (dump_file, "%s is a non-pointer variable,"
2507 "ignoring constraint:",
2508 get_varinfo (lhs.var)->name);
2509 dump_constraint (dump_file, c);
2511 VEC_replace (constraint_t, constraints, i, NULL);
2517 if (dump_file && (dump_flags & TDF_DETAILS))
2520 fprintf (dump_file, "%s is a non-pointer variable,"
2521 "ignoring constraint:",
2522 get_varinfo (rhs.var)->name);
2523 dump_constraint (dump_file, c);
2525 VEC_replace (constraint_t, constraints, i, NULL);
2529 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2530 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2531 c->lhs.var = lhsvar;
2532 c->rhs.var = rhsvar;
2537 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2538 part of an SCC, false otherwise. */
2541 eliminate_indirect_cycles (unsigned int node)
2543 if (graph->indirect_cycles[node] != -1
2544 && !bitmap_empty_p (get_varinfo (node)->solution))
2547 VEC(unsigned,heap) *queue = NULL;
2549 unsigned int to = find (graph->indirect_cycles[node]);
2552 /* We can't touch the solution set and call unify_nodes
2553 at the same time, because unify_nodes is going to do
2554 bitmap unions into it. */
2556 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2558 if (find (i) == i && i != to)
2561 VEC_safe_push (unsigned, heap, queue, i);
2566 VEC_iterate (unsigned, queue, queuepos, i);
2569 unify_nodes (graph, to, i, true);
2571 VEC_free (unsigned, heap, queue);
2577 /* Solve the constraint graph GRAPH using our worklist solver.
2578 This is based on the PW* family of solvers from the "Efficient Field
2579 Sensitive Pointer Analysis for C" paper.
2580 It works by iterating over all the graph nodes, processing the complex
2581 constraints and propagating the copy constraints, until everything stops
2582 changed. This corresponds to steps 6-8 in the solving list given above. */
2585 solve_graph (constraint_graph_t graph)
2587 unsigned int size = graph->size;
2592 changed = sbitmap_alloc (size);
2593 sbitmap_zero (changed);
2595 /* Mark all initial non-collapsed nodes as changed. */
2596 for (i = 0; i < size; i++)
2598 varinfo_t ivi = get_varinfo (i);
2599 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2600 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2601 || VEC_length (constraint_t, graph->complex[i]) > 0))
2603 SET_BIT (changed, i);
2608 /* Allocate a bitmap to be used to store the changed bits. */
2609 pts = BITMAP_ALLOC (&pta_obstack);
2611 while (changed_count > 0)
2614 struct topo_info *ti = init_topo_info ();
2617 bitmap_obstack_initialize (&iteration_obstack);
2619 compute_topo_order (graph, ti);
2621 while (VEC_length (unsigned, ti->topo_order) != 0)
2624 i = VEC_pop (unsigned, ti->topo_order);
2626 /* If this variable is not a representative, skip it. */
2630 /* In certain indirect cycle cases, we may merge this
2631 variable to another. */
2632 if (eliminate_indirect_cycles (i) && find (i) != i)
2635 /* If the node has changed, we need to process the
2636 complex constraints and outgoing edges again. */
2637 if (TEST_BIT (changed, i))
2642 VEC(constraint_t,heap) *complex = graph->complex[i];
2643 bool solution_empty;
2645 RESET_BIT (changed, i);
2648 /* Compute the changed set of solution bits. */
2649 bitmap_and_compl (pts, get_varinfo (i)->solution,
2650 get_varinfo (i)->oldsolution);
2652 if (bitmap_empty_p (pts))
2655 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2657 solution = get_varinfo (i)->solution;
2658 solution_empty = bitmap_empty_p (solution);
2660 /* Process the complex constraints */
2661 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2663 /* XXX: This is going to unsort the constraints in
2664 some cases, which will occasionally add duplicate
2665 constraints during unification. This does not
2666 affect correctness. */
2667 c->lhs.var = find (c->lhs.var);
2668 c->rhs.var = find (c->rhs.var);
2670 /* The only complex constraint that can change our
2671 solution to non-empty, given an empty solution,
2672 is a constraint where the lhs side is receiving
2673 some set from elsewhere. */
2674 if (!solution_empty || c->lhs.type != DEREF)
2675 do_complex_constraint (graph, c, pts);
2678 solution_empty = bitmap_empty_p (solution);
2680 if (!solution_empty)
2683 unsigned eff_escaped_id = find (escaped_id);
2685 /* Propagate solution to all successors. */
2686 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2692 unsigned int to = find (j);
2693 tmp = get_varinfo (to)->solution;
2696 /* Don't try to propagate to ourselves. */
2700 /* If we propagate from ESCAPED use ESCAPED as
2702 if (i == eff_escaped_id)
2703 flag = bitmap_set_bit (tmp, escaped_id);
2705 flag = set_union_with_increment (tmp, pts, 0);
2709 get_varinfo (to)->solution = tmp;
2710 if (!TEST_BIT (changed, to))
2712 SET_BIT (changed, to);
2720 free_topo_info (ti);
2721 bitmap_obstack_release (&iteration_obstack);
2725 sbitmap_free (changed);
2726 bitmap_obstack_release (&oldpta_obstack);
2729 /* Map from trees to variable infos. */
2730 static struct pointer_map_t *vi_for_tree;
2733 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2736 insert_vi_for_tree (tree t, varinfo_t vi)
2738 void **slot = pointer_map_insert (vi_for_tree, t);
2740 gcc_assert (*slot == NULL);
2744 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2745 exist in the map, return NULL, otherwise, return the varinfo we found. */
2748 lookup_vi_for_tree (tree t)
2750 void **slot = pointer_map_contains (vi_for_tree, t);
2754 return (varinfo_t) *slot;
2757 /* Return a printable name for DECL */
2760 alias_get_name (tree decl)
2764 int num_printed = 0;
2766 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2767 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2769 res= get_name (decl);
2777 if (TREE_CODE (decl) == SSA_NAME)
2779 num_printed = asprintf (&temp, "%s_%u",
2780 alias_get_name (SSA_NAME_VAR (decl)),
2781 SSA_NAME_VERSION (decl));
2783 else if (DECL_P (decl))
2785 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2787 if (num_printed > 0)
2789 res = ggc_strdup (temp);
2795 /* Find the variable id for tree T in the map.
2796 If T doesn't exist in the map, create an entry for it and return it. */
2799 get_vi_for_tree (tree t)
2801 void **slot = pointer_map_contains (vi_for_tree, t);
2803 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2805 return (varinfo_t) *slot;
2808 /* Get a scalar constraint expression for a new temporary variable. */
2810 static struct constraint_expr
2811 new_scalar_tmp_constraint_exp (const char *name)
2813 struct constraint_expr tmp;
2816 vi = new_var_info (NULL_TREE, name);
2820 vi->is_full_var = 1;
2829 /* Get a constraint expression vector from an SSA_VAR_P node.
2830 If address_p is true, the result will be taken its address of. */
2833 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2835 struct constraint_expr cexpr;
2838 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2839 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2841 /* For parameters, get at the points-to set for the actual parm
2843 if (TREE_CODE (t) == SSA_NAME
2844 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2845 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2846 && SSA_NAME_IS_DEFAULT_DEF (t))
2848 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2852 vi = get_vi_for_tree (t);
2854 cexpr.type = SCALAR;
2856 /* If we determine the result is "anything", and we know this is readonly,
2857 say it points to readonly memory instead. */
2858 if (cexpr.var == anything_id && TREE_READONLY (t))
2861 cexpr.type = ADDRESSOF;
2862 cexpr.var = readonly_id;
2865 /* If we are not taking the address of the constraint expr, add all
2866 sub-fiels of the variable as well. */
2868 && !vi->is_full_var)
2870 for (; vi; vi = vi->next)
2873 VEC_safe_push (ce_s, heap, *results, &cexpr);
2878 VEC_safe_push (ce_s, heap, *results, &cexpr);
2881 /* Process constraint T, performing various simplifications and then
2882 adding it to our list of overall constraints. */
2885 process_constraint (constraint_t t)
2887 struct constraint_expr rhs = t->rhs;
2888 struct constraint_expr lhs = t->lhs;
2890 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2891 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2893 /* If we didn't get any useful constraint from the lhs we get
2894 &ANYTHING as fallback from get_constraint_for. Deal with
2895 it here by turning it into *ANYTHING. */
2896 if (lhs.type == ADDRESSOF
2897 && lhs.var == anything_id)
2900 /* ADDRESSOF on the lhs is invalid. */
2901 gcc_assert (lhs.type != ADDRESSOF);
2903 /* We shouldn't add constraints from things that cannot have pointers.
2904 It's not completely trivial to avoid in the callers, so do it here. */
2905 if (rhs.type != ADDRESSOF
2906 && !get_varinfo (rhs.var)->may_have_pointers)
2909 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2910 if (!get_varinfo (lhs.var)->may_have_pointers)
2913 /* This can happen in our IR with things like n->a = *p */
2914 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2916 /* Split into tmp = *rhs, *lhs = tmp */
2917 struct constraint_expr tmplhs;
2918 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2919 process_constraint (new_constraint (tmplhs, rhs));
2920 process_constraint (new_constraint (lhs, tmplhs));
2922 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2924 /* Split into tmp = &rhs, *lhs = tmp */
2925 struct constraint_expr tmplhs;
2926 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2927 process_constraint (new_constraint (tmplhs, rhs));
2928 process_constraint (new_constraint (lhs, tmplhs));
2932 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2933 VEC_safe_push (constraint_t, heap, constraints, t);
2938 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2941 static HOST_WIDE_INT
2942 bitpos_of_field (const tree fdecl)
2944 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2945 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2948 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2949 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2953 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2954 resulting constraint expressions in *RESULTS. */
2957 get_constraint_for_ptr_offset (tree ptr, tree offset,
2958 VEC (ce_s, heap) **results)
2960 struct constraint_expr c;
2962 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2964 /* If we do not do field-sensitive PTA adding offsets to pointers
2965 does not change the points-to solution. */
2966 if (!use_field_sensitive)
2968 get_constraint_for_rhs (ptr, results);
2972 /* If the offset is not a non-negative integer constant that fits
2973 in a HOST_WIDE_INT, we have to fall back to a conservative
2974 solution which includes all sub-fields of all pointed-to
2975 variables of ptr. */
2976 if (offset == NULL_TREE
2977 || !host_integerp (offset, 0))
2978 rhsoffset = UNKNOWN_OFFSET;
2981 /* Make sure the bit-offset also fits. */
2982 rhsunitoffset = TREE_INT_CST_LOW (offset);
2983 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2984 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2985 rhsoffset = UNKNOWN_OFFSET;
2988 get_constraint_for_rhs (ptr, results);
2992 /* As we are eventually appending to the solution do not use
2993 VEC_iterate here. */
2994 n = VEC_length (ce_s, *results);
2995 for (j = 0; j < n; j++)
2998 c = *VEC_index (ce_s, *results, j);
2999 curr = get_varinfo (c.var);
3001 if (c.type == ADDRESSOF
3002 /* If this varinfo represents a full variable just use it. */
3003 && curr->is_full_var)
3005 else if (c.type == ADDRESSOF
3006 /* If we do not know the offset add all subfields. */
3007 && rhsoffset == UNKNOWN_OFFSET)
3009 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3012 struct constraint_expr c2;
3014 c2.type = ADDRESSOF;
3016 if (c2.var != c.var)
3017 VEC_safe_push (ce_s, heap, *results, &c2);
3022 else if (c.type == ADDRESSOF)
3025 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3027 /* Search the sub-field which overlaps with the
3028 pointed-to offset. If the result is outside of the variable
3029 we have to provide a conservative result, as the variable is
3030 still reachable from the resulting pointer (even though it
3031 technically cannot point to anything). The last and first
3032 sub-fields are such conservative results.
3033 ??? If we always had a sub-field for &object + 1 then
3034 we could represent this in a more precise way. */
3036 && curr->offset < offset)
3038 temp = first_or_preceding_vi_for_offset (curr, offset);
3040 /* If the found variable is not exactly at the pointed to
3041 result, we have to include the next variable in the
3042 solution as well. Otherwise two increments by offset / 2
3043 do not result in the same or a conservative superset
3045 if (temp->offset != offset
3046 && temp->next != NULL)
3048 struct constraint_expr c2;
3049 c2.var = temp->next->id;
3050 c2.type = ADDRESSOF;
3052 VEC_safe_push (ce_s, heap, *results, &c2);
3058 c.offset = rhsoffset;
3060 VEC_replace (ce_s, *results, j, &c);
3065 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3066 If address_p is true the result will be taken its address of.
3067 If lhs_p is true then the constraint expression is assumed to be used
3071 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3072 bool address_p, bool lhs_p)
3075 HOST_WIDE_INT bitsize = -1;
3076 HOST_WIDE_INT bitmaxsize = -1;
3077 HOST_WIDE_INT bitpos;
3079 struct constraint_expr *result;
3081 /* Some people like to do cute things like take the address of
3084 while (handled_component_p (forzero)
3085 || INDIRECT_REF_P (forzero)
3086 || TREE_CODE (forzero) == MEM_REF)
3087 forzero = TREE_OPERAND (forzero, 0);
3089 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3091 struct constraint_expr temp;
3094 temp.var = integer_id;
3096 VEC_safe_push (ce_s, heap, *results, &temp);
3100 /* Handle type-punning through unions. If we are extracting a pointer
3101 from a union via a possibly type-punning access that pointer
3102 points to anything, similar to a conversion of an integer to
3108 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3109 u = TREE_OPERAND (u, 0))
3110 if (TREE_CODE (u) == COMPONENT_REF
3111 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3113 struct constraint_expr temp;
3116 temp.var = anything_id;
3117 temp.type = ADDRESSOF;
3118 VEC_safe_push (ce_s, heap, *results, &temp);
3123 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3125 /* Pretend to take the address of the base, we'll take care of
3126 adding the required subset of sub-fields below. */
3127 get_constraint_for_1 (t, results, true, lhs_p);
3128 gcc_assert (VEC_length (ce_s, *results) == 1);
3129 result = VEC_last (ce_s, *results);
3131 if (result->type == SCALAR
3132 && get_varinfo (result->var)->is_full_var)
3133 /* For single-field vars do not bother about the offset. */
3135 else if (result->type == SCALAR)
3137 /* In languages like C, you can access one past the end of an
3138 array. You aren't allowed to dereference it, so we can
3139 ignore this constraint. When we handle pointer subtraction,
3140 we may have to do something cute here. */
3142 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3145 /* It's also not true that the constraint will actually start at the
3146 right offset, it may start in some padding. We only care about
3147 setting the constraint to the first actual field it touches, so
3149 struct constraint_expr cexpr = *result;
3151 VEC_pop (ce_s, *results);
3153 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3155 if (ranges_overlap_p (curr->offset, curr->size,
3156 bitpos, bitmaxsize))
3158 cexpr.var = curr->id;
3159 VEC_safe_push (ce_s, heap, *results, &cexpr);
3164 /* If we are going to take the address of this field then
3165 to be able to compute reachability correctly add at least
3166 the last field of the variable. */
3168 && VEC_length (ce_s, *results) == 0)
3170 curr = get_varinfo (cexpr.var);
3171 while (curr->next != NULL)
3173 cexpr.var = curr->id;
3174 VEC_safe_push (ce_s, heap, *results, &cexpr);
3176 else if (VEC_length (ce_s, *results) == 0)
3177 /* Assert that we found *some* field there. The user couldn't be
3178 accessing *only* padding. */
3179 /* Still the user could access one past the end of an array
3180 embedded in a struct resulting in accessing *only* padding. */
3181 /* Or accessing only padding via type-punning to a type
3182 that has a filed just in padding space. */
3184 cexpr.type = SCALAR;
3185 cexpr.var = anything_id;
3187 VEC_safe_push (ce_s, heap, *results, &cexpr);
3190 else if (bitmaxsize == 0)
3192 if (dump_file && (dump_flags & TDF_DETAILS))
3193 fprintf (dump_file, "Access to zero-sized part of variable,"
3197 if (dump_file && (dump_flags & TDF_DETAILS))
3198 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3200 else if (result->type == DEREF)
3202 /* If we do not know exactly where the access goes say so. Note
3203 that only for non-structure accesses we know that we access
3204 at most one subfiled of any variable. */
3206 || bitsize != bitmaxsize
3207 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3208 || result->offset == UNKNOWN_OFFSET)
3209 result->offset = UNKNOWN_OFFSET;
3211 result->offset += bitpos;
3213 else if (result->type == ADDRESSOF)
3215 /* We can end up here for component references on a
3216 VIEW_CONVERT_EXPR <>(&foobar). */
3217 result->type = SCALAR;
3218 result->var = anything_id;
3226 /* Dereference the constraint expression CONS, and return the result.
3227 DEREF (ADDRESSOF) = SCALAR
3228 DEREF (SCALAR) = DEREF
3229 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3230 This is needed so that we can handle dereferencing DEREF constraints. */
3233 do_deref (VEC (ce_s, heap) **constraints)
3235 struct constraint_expr *c;
3238 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3240 if (c->type == SCALAR)
3242 else if (c->type == ADDRESSOF)
3244 else if (c->type == DEREF)
3246 struct constraint_expr tmplhs;
3247 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3248 process_constraint (new_constraint (tmplhs, *c));
3249 c->var = tmplhs.var;
3256 /* Given a tree T, return the constraint expression for taking the
3260 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3262 struct constraint_expr *c;
3265 get_constraint_for_1 (t, results, true, true);
3267 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3269 if (c->type == DEREF)
3272 c->type = ADDRESSOF;
3276 /* Given a tree T, return the constraint expression for it. */
3279 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3282 struct constraint_expr temp;
3284 /* x = integer is all glommed to a single variable, which doesn't
3285 point to anything by itself. That is, of course, unless it is an
3286 integer constant being treated as a pointer, in which case, we
3287 will return that this is really the addressof anything. This
3288 happens below, since it will fall into the default case. The only
3289 case we know something about an integer treated like a pointer is
3290 when it is the NULL pointer, and then we just say it points to
3293 Do not do that if -fno-delete-null-pointer-checks though, because
3294 in that case *NULL does not fail, so it _should_ alias *anything.
3295 It is not worth adding a new option or renaming the existing one,
3296 since this case is relatively obscure. */
3297 if ((TREE_CODE (t) == INTEGER_CST
3298 && integer_zerop (t))
3299 /* The only valid CONSTRUCTORs in gimple with pointer typed
3300 elements are zero-initializer. But in IPA mode we also
3301 process global initializers, so verify at least. */
3302 || (TREE_CODE (t) == CONSTRUCTOR
3303 && CONSTRUCTOR_NELTS (t) == 0))
3305 if (flag_delete_null_pointer_checks)
3306 temp.var = nothing_id;
3308 temp.var = nonlocal_id;
3309 temp.type = ADDRESSOF;
3311 VEC_safe_push (ce_s, heap, *results, &temp);
3315 /* String constants are read-only. */
3316 if (TREE_CODE (t) == STRING_CST)
3318 temp.var = readonly_id;
3321 VEC_safe_push (ce_s, heap, *results, &temp);
3325 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3327 case tcc_expression:
3329 switch (TREE_CODE (t))
3332 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3340 switch (TREE_CODE (t))
3344 struct constraint_expr cs;
3346 tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
3347 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
3350 /* If we are not taking the address then make sure to process
3351 all subvariables we might access. */
3352 cs = *VEC_last (ce_s, *results);
3354 || cs.type != SCALAR)
3357 vi = get_varinfo (cs.var);
3359 if (!vi->is_full_var
3362 unsigned HOST_WIDE_INT size;
3363 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3364 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3367 for (; curr; curr = curr->next)
3369 if (curr->offset - vi->offset < size)
3372 VEC_safe_push (ce_s, heap, *results, &cs);
3381 case ARRAY_RANGE_REF:
3383 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3385 case VIEW_CONVERT_EXPR:
3386 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3389 /* We are missing handling for TARGET_MEM_REF here. */
3394 case tcc_exceptional:
3396 switch (TREE_CODE (t))
3400 get_constraint_for_ssa_var (t, results, address_p);
3407 VEC (ce_s, heap) *tmp = NULL;
3408 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3410 struct constraint_expr *rhsp;
3412 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3413 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3414 VEC_safe_push (ce_s, heap, *results, rhsp);
3415 VEC_truncate (ce_s, tmp, 0);
3417 VEC_free (ce_s, heap, tmp);
3418 /* We do not know whether the constructor was complete,
3419 so technically we have to add &NOTHING or &ANYTHING
3420 like we do for an empty constructor as well. */
3427 case tcc_declaration:
3429 get_constraint_for_ssa_var (t, results, address_p);
3434 /* We cannot refer to automatic variables through constants. */
3435 temp.type = ADDRESSOF;
3436 temp.var = nonlocal_id;
3438 VEC_safe_push (ce_s, heap, *results, &temp);
3444 /* The default fallback is a constraint from anything. */
3445 temp.type = ADDRESSOF;
3446 temp.var = anything_id;
3448 VEC_safe_push (ce_s, heap, *results, &temp);
3451 /* Given a gimple tree T, return the constraint expression vector for it. */
3454 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3456 gcc_assert (VEC_length (ce_s, *results) == 0);
3458 get_constraint_for_1 (t, results, false, true);
3461 /* Given a gimple tree T, return the constraint expression vector for it
3462 to be used as the rhs of a constraint. */
3465 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3467 gcc_assert (VEC_length (ce_s, *results) == 0);
3469 get_constraint_for_1 (t, results, false, false);
3473 /* Efficiently generates constraints from all entries in *RHSC to all
3474 entries in *LHSC. */
3477 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3479 struct constraint_expr *lhsp, *rhsp;
3482 if (VEC_length (ce_s, lhsc) <= 1
3483 || VEC_length (ce_s, rhsc) <= 1)
3485 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3486 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3487 process_constraint (new_constraint (*lhsp, *rhsp));
3491 struct constraint_expr tmp;
3492 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3493 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3494 process_constraint (new_constraint (tmp, *rhsp));
3495 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3496 process_constraint (new_constraint (*lhsp, tmp));
3500 /* Handle aggregate copies by expanding into copies of the respective
3501 fields of the structures. */
3504 do_structure_copy (tree lhsop, tree rhsop)
3506 struct constraint_expr *lhsp, *rhsp;
3507 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3510 get_constraint_for (lhsop, &lhsc);
3511 get_constraint_for_rhs (rhsop, &rhsc);
3512 lhsp = VEC_index (ce_s, lhsc, 0);
3513 rhsp = VEC_index (ce_s, rhsc, 0);
3514 if (lhsp->type == DEREF
3515 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3516 || rhsp->type == DEREF)
3518 if (lhsp->type == DEREF)
3520 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3521 lhsp->offset = UNKNOWN_OFFSET;
3523 if (rhsp->type == DEREF)
3525 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3526 rhsp->offset = UNKNOWN_OFFSET;
3528 process_all_all_constraints (lhsc, rhsc);
3530 else if (lhsp->type == SCALAR
3531 && (rhsp->type == SCALAR
3532 || rhsp->type == ADDRESSOF))
3534 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3535 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3537 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3538 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3539 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3541 varinfo_t lhsv, rhsv;
3542 rhsp = VEC_index (ce_s, rhsc, k);
3543 lhsv = get_varinfo (lhsp->var);
3544 rhsv = get_varinfo (rhsp->var);
3545 if (lhsv->may_have_pointers
3546 && (lhsv->is_full_var
3547 || rhsv->is_full_var
3548 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3549 rhsv->offset + lhsoffset, rhsv->size)))
3550 process_constraint (new_constraint (*lhsp, *rhsp));
3551 if (!rhsv->is_full_var
3552 && (lhsv->is_full_var
3553 || (lhsv->offset + rhsoffset + lhsv->size
3554 > rhsv->offset + lhsoffset + rhsv->size)))
3557 if (k >= VEC_length (ce_s, rhsc))
3567 VEC_free (ce_s, heap, lhsc);
3568 VEC_free (ce_s, heap, rhsc);
3571 /* Create constraints ID = { rhsc }. */
3574 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3576 struct constraint_expr *c;
3577 struct constraint_expr includes;
3581 includes.offset = 0;
3582 includes.type = SCALAR;
3584 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3585 process_constraint (new_constraint (includes, *c));
3588 /* Create a constraint ID = OP. */
3591 make_constraint_to (unsigned id, tree op)
3593 VEC(ce_s, heap) *rhsc = NULL;
3594 get_constraint_for_rhs (op, &rhsc);
3595 make_constraints_to (id, rhsc);
3596 VEC_free (ce_s, heap, rhsc);
3599 /* Create a constraint ID = &FROM. */
3602 make_constraint_from (varinfo_t vi, int from)
3604 struct constraint_expr lhs, rhs;
3612 rhs.type = ADDRESSOF;
3613 process_constraint (new_constraint (lhs, rhs));
3616 /* Create a constraint ID = FROM. */
3619 make_copy_constraint (varinfo_t vi, int from)
3621 struct constraint_expr lhs, rhs;
3630 process_constraint (new_constraint (lhs, rhs));
3633 /* Make constraints necessary to make OP escape. */
3636 make_escape_constraint (tree op)
3638 make_constraint_to (escaped_id, op);
3641 /* Add constraints to that the solution of VI is transitively closed. */
3644 make_transitive_closure_constraints (varinfo_t vi)
3646 struct constraint_expr lhs, rhs;
3655 process_constraint (new_constraint (lhs, rhs));
3657 /* VAR = VAR + UNKNOWN; */
3663 rhs.offset = UNKNOWN_OFFSET;
3664 process_constraint (new_constraint (lhs, rhs));
3667 /* Create a new artificial heap variable with NAME.
3668 Return the created variable. */
3671 make_heapvar_for (varinfo_t lhs, const char *name)
3674 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3676 if (heapvar == NULL_TREE)
3679 heapvar = create_tmp_var_raw (ptr_type_node, name);
3680 DECL_EXTERNAL (heapvar) = 1;
3682 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3684 ann = get_var_ann (heapvar);
3685 ann->is_heapvar = 1;
3688 /* For global vars we need to add a heapvar to the list of referenced
3689 vars of a different function than it was created for originally. */
3690 if (cfun && gimple_referenced_vars (cfun))
3691 add_referenced_var (heapvar);
3693 vi = new_var_info (heapvar, name);
3694 vi->is_artificial_var = true;
3695 vi->is_heap_var = true;
3696 vi->is_unknown_size_var = true;
3700 vi->is_full_var = true;
3701 insert_vi_for_tree (heapvar, vi);
3706 /* Create a new artificial heap variable with NAME and make a
3707 constraint from it to LHS. Return the created variable. */
3710 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3712 varinfo_t vi = make_heapvar_for (lhs, name);
3713 make_constraint_from (lhs, vi->id);
3718 /* Create a new artificial heap variable with NAME and make a
3719 constraint from it to LHS. Set flags according to a tag used
3720 for tracking restrict pointers. */
3723 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3726 vi = make_constraint_from_heapvar (lhs, name);
3727 vi->is_restrict_var = 1;
3728 vi->is_global_var = 0;
3729 vi->is_special_var = 1;
3730 vi->may_have_pointers = 0;
3733 /* In IPA mode there are varinfos for different aspects of reach
3734 function designator. One for the points-to set of the return
3735 value, one for the variables that are clobbered by the function,
3736 one for its uses and one for each parameter (including a single
3737 glob for remaining variadic arguments). */
3739 enum { fi_clobbers = 1, fi_uses = 2,
3740 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3742 /* Get a constraint for the requested part of a function designator FI
3743 when operating in IPA mode. */
3745 static struct constraint_expr
3746 get_function_part_constraint (varinfo_t fi, unsigned part)
3748 struct constraint_expr c;
3750 gcc_assert (in_ipa_mode);
3752 if (fi->id == anything_id)
3754 /* ??? We probably should have a ANYFN special variable. */
3755 c.var = anything_id;
3759 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3761 varinfo_t ai = first_vi_for_offset (fi, part);
3765 c.var = anything_id;
3779 /* For non-IPA mode, generate constraints necessary for a call on the
3783 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3785 struct constraint_expr rhsc;
3787 bool returns_uses = false;
3789 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3791 tree arg = gimple_call_arg (stmt, i);
3792 int flags = gimple_call_arg_flags (stmt, i);
3794 /* If the argument is not used we can ignore it. */
3795 if (flags & EAF_UNUSED)
3798 /* As we compute ESCAPED context-insensitive we do not gain
3799 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3800 set. The argument would still get clobbered through the
3802 ??? We might get away with less (and more precise) constraints
3803 if using a temporary for transitively closing things. */
3804 if ((flags & EAF_NOCLOBBER)
3805 && (flags & EAF_NOESCAPE))
3807 varinfo_t uses = get_call_use_vi (stmt);
3808 if (!(flags & EAF_DIRECT))
3809 make_transitive_closure_constraints (uses);
3810 make_constraint_to (uses->id, arg);
3811 returns_uses = true;
3813 else if (flags & EAF_NOESCAPE)
3815 varinfo_t uses = get_call_use_vi (stmt);
3816 varinfo_t clobbers = get_call_clobber_vi (stmt);
3817 if (!(flags & EAF_DIRECT))
3819 make_transitive_closure_constraints (uses);
3820 make_transitive_closure_constraints (clobbers);
3822 make_constraint_to (uses->id, arg);
3823 make_constraint_to (clobbers->id, arg);
3824 returns_uses = true;
3827 make_escape_constraint (arg);
3830 /* If we added to the calls uses solution make sure we account for
3831 pointers to it to be returned. */
3834 rhsc.var = get_call_use_vi (stmt)->id;
3837 VEC_safe_push (ce_s, heap, *results, &rhsc);
3840 /* The static chain escapes as well. */
3841 if (gimple_call_chain (stmt))
3842 make_escape_constraint (gimple_call_chain (stmt));
3844 /* And if we applied NRV the address of the return slot escapes as well. */
3845 if (gimple_call_return_slot_opt_p (stmt)
3846 && gimple_call_lhs (stmt) != NULL_TREE
3847 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3849 VEC(ce_s, heap) *tmpc = NULL;
3850 struct constraint_expr lhsc, *c;
3851 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3852 lhsc.var = escaped_id;
3855 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3856 process_constraint (new_constraint (lhsc, *c));
3857 VEC_free(ce_s, heap, tmpc);
3860 /* Regular functions return nonlocal memory. */
3861 rhsc.var = nonlocal_id;
3864 VEC_safe_push (ce_s, heap, *results, &rhsc);
3867 /* For non-IPA mode, generate constraints necessary for a call
3868 that returns a pointer and assigns it to LHS. This simply makes
3869 the LHS point to global and escaped variables. */
3872 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3875 VEC(ce_s, heap) *lhsc = NULL;
3877 get_constraint_for (lhs, &lhsc);
3878 /* If the store is to a global decl make sure to
3879 add proper escape constraints. */
3880 lhs = get_base_address (lhs);
3883 && is_global_var (lhs))
3885 struct constraint_expr tmpc;
3886 tmpc.var = escaped_id;
3889 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3892 /* If the call returns an argument unmodified override the rhs
3894 flags = gimple_call_return_flags (stmt);
3895 if (flags & ERF_RETURNS_ARG
3896 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3900 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3901 get_constraint_for (arg, &rhsc);
3902 process_all_all_constraints (lhsc, rhsc);
3903 VEC_free (ce_s, heap, rhsc);
3905 else if (flags & ERF_NOALIAS)
3908 struct constraint_expr tmpc;
3910 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3911 /* We delay marking allocated storage global until we know if
3913 DECL_EXTERNAL (vi->decl) = 0;
3914 vi->is_global_var = 0;
3915 /* If this is not a real malloc call assume the memory was
3916 initialized and thus may point to global memory. All
3917 builtin functions with the malloc attribute behave in a sane way. */
3919 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3920 make_constraint_from (vi, nonlocal_id);
3923 tmpc.type = ADDRESSOF;
3924 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3927 process_all_all_constraints (lhsc, rhsc);
3929 VEC_free (ce_s, heap, lhsc);
3932 /* For non-IPA mode, generate constraints necessary for a call of a
3933 const function that returns a pointer in the statement STMT. */
3936 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3938 struct constraint_expr rhsc;
3941 /* Treat nested const functions the same as pure functions as far
3942 as the static chain is concerned. */
3943 if (gimple_call_chain (stmt))
3945 varinfo_t uses = get_call_use_vi (stmt);
3946 make_transitive_closure_constraints (uses);
3947 make_constraint_to (uses->id, gimple_call_chain (stmt));
3948 rhsc.var = uses->id;
3951 VEC_safe_push (ce_s, heap, *results, &rhsc);
3954 /* May return arguments. */
3955 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3957 tree arg = gimple_call_arg (stmt, k);
3958 VEC(ce_s, heap) *argc = NULL;
3960 struct constraint_expr *argp;
3961 get_constraint_for_rhs (arg, &argc);
3962 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3963 VEC_safe_push (ce_s, heap, *results, argp);
3964 VEC_free(ce_s, heap, argc);
3967 /* May return addresses of globals. */
3968 rhsc.var = nonlocal_id;
3970 rhsc.type = ADDRESSOF;
3971 VEC_safe_push (ce_s, heap, *results, &rhsc);
3974 /* For non-IPA mode, generate constraints necessary for a call to a
3975 pure function in statement STMT. */
3978 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3980 struct constraint_expr rhsc;
3982 varinfo_t uses = NULL;
3984 /* Memory reached from pointer arguments is call-used. */
3985 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3987 tree arg = gimple_call_arg (stmt, i);
3990 uses = get_call_use_vi (stmt);
3991 make_transitive_closure_constraints (uses);
3993 make_constraint_to (uses->id, arg);
3996 /* The static chain is used as well. */
3997 if (gimple_call_chain (stmt))
4001 uses = get_call_use_vi (stmt);
4002 make_transitive_closure_constraints (uses);
4004 make_constraint_to (uses->id, gimple_call_chain (stmt));
4007 /* Pure functions may return call-used and nonlocal memory. */
4010 rhsc.var = uses->id;
4013 VEC_safe_push (ce_s, heap, *results, &rhsc);
4015 rhsc.var = nonlocal_id;
4018 VEC_safe_push (ce_s, heap, *results, &rhsc);
4022 /* Return the varinfo for the callee of CALL. */
4025 get_fi_for_callee (gimple call)
4029 gcc_assert (!gimple_call_internal_p (call));
4031 /* If we can directly resolve the function being called, do so.
4032 Otherwise, it must be some sort of indirect expression that
4033 we should still be able to handle. */
4034 decl = gimple_call_fndecl (call);
4036 return get_vi_for_tree (decl);
4038 decl = gimple_call_fn (call);
4039 /* The function can be either an SSA name pointer or,
4040 worse, an OBJ_TYPE_REF. In this case we have no
4041 clue and should be getting ANYFN (well, ANYTHING for now). */
4042 if (TREE_CODE (decl) == SSA_NAME)
4044 if (TREE_CODE (decl) == SSA_NAME
4045 && (TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
4046 || TREE_CODE (SSA_NAME_VAR (decl)) == RESULT_DECL)
4047 && SSA_NAME_IS_DEFAULT_DEF (decl))
4048 decl = SSA_NAME_VAR (decl);
4049 return get_vi_for_tree (decl);
4051 else if (TREE_CODE (decl) == INTEGER_CST
4052 || TREE_CODE (decl) == OBJ_TYPE_REF)
4053 return get_varinfo (anything_id);
4058 /* Walk statement T setting up aliasing constraints according to the
4059 references found in T. This function is the main part of the
4060 constraint builder. AI points to auxiliary alias information used
4061 when building alias sets and computing alias grouping heuristics. */
4064 find_func_aliases (gimple origt)
4067 VEC(ce_s, heap) *lhsc = NULL;
4068 VEC(ce_s, heap) *rhsc = NULL;
4069 struct constraint_expr *c;
4072 /* Now build constraints expressions. */
4073 if (gimple_code (t) == GIMPLE_PHI)
4078 /* For a phi node, assign all the arguments to
4080 get_constraint_for (gimple_phi_result (t), &lhsc);
4081 for (i = 0; i < gimple_phi_num_args (t); i++)
4083 tree strippedrhs = PHI_ARG_DEF (t, i);
4085 STRIP_NOPS (strippedrhs);
4086 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4088 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4090 struct constraint_expr *c2;
4091 while (VEC_length (ce_s, rhsc) > 0)
4093 c2 = VEC_last (ce_s, rhsc);
4094 process_constraint (new_constraint (*c, *c2));
4095 VEC_pop (ce_s, rhsc);
4100 /* In IPA mode, we need to generate constraints to pass call
4101 arguments through their calls. There are two cases,
4102 either a GIMPLE_CALL returning a value, or just a plain
4103 GIMPLE_CALL when we are not.
4105 In non-ipa mode, we need to generate constraints for each
4106 pointer passed by address. */
4107 else if (is_gimple_call (t))
4109 tree fndecl = gimple_call_fndecl (t);
4110 if (fndecl != NULL_TREE
4111 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4112 /* ??? All builtins that are handled here need to be handled
4113 in the alias-oracle query functions explicitly! */
4114 switch (DECL_FUNCTION_CODE (fndecl))
4116 /* All the following functions return a pointer to the same object
4117 as their first argument points to. The functions do not add
4118 to the ESCAPED solution. The functions make the first argument
4119 pointed to memory point to what the second argument pointed to
4120 memory points to. */
4121 case BUILT_IN_STRCPY:
4122 case BUILT_IN_STRNCPY:
4123 case BUILT_IN_BCOPY:
4124 case BUILT_IN_MEMCPY:
4125 case BUILT_IN_MEMMOVE:
4126 case BUILT_IN_MEMPCPY:
4127 case BUILT_IN_STPCPY:
4128 case BUILT_IN_STPNCPY:
4129 case BUILT_IN_STRCAT:
4130 case BUILT_IN_STRNCAT:
4132 tree res = gimple_call_lhs (t);
4133 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4134 == BUILT_IN_BCOPY ? 1 : 0));
4135 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4136 == BUILT_IN_BCOPY ? 0 : 1));
4137 if (res != NULL_TREE)
4139 get_constraint_for (res, &lhsc);
4140 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4141 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4142 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4143 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4145 get_constraint_for (dest, &rhsc);
4146 process_all_all_constraints (lhsc, rhsc);
4147 VEC_free (ce_s, heap, lhsc);
4148 VEC_free (ce_s, heap, rhsc);
4150 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4151 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4154 process_all_all_constraints (lhsc, rhsc);
4155 VEC_free (ce_s, heap, lhsc);
4156 VEC_free (ce_s, heap, rhsc);
4159 case BUILT_IN_MEMSET:
4161 tree res = gimple_call_lhs (t);
4162 tree dest = gimple_call_arg (t, 0);
4165 struct constraint_expr ac;
4166 if (res != NULL_TREE)
4168 get_constraint_for (res, &lhsc);
4169 get_constraint_for (dest, &rhsc);
4170 process_all_all_constraints (lhsc, rhsc);
4171 VEC_free (ce_s, heap, lhsc);
4172 VEC_free (ce_s, heap, rhsc);
4174 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4176 if (flag_delete_null_pointer_checks
4177 && integer_zerop (gimple_call_arg (t, 1)))
4179 ac.type = ADDRESSOF;
4180 ac.var = nothing_id;
4185 ac.var = integer_id;
4188 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4189 process_constraint (new_constraint (*lhsp, ac));
4190 VEC_free (ce_s, heap, lhsc);
4193 /* All the following functions do not return pointers, do not
4194 modify the points-to sets of memory reachable from their
4195 arguments and do not add to the ESCAPED solution. */
4196 case BUILT_IN_SINCOS:
4197 case BUILT_IN_SINCOSF:
4198 case BUILT_IN_SINCOSL:
4199 case BUILT_IN_FREXP:
4200 case BUILT_IN_FREXPF:
4201 case BUILT_IN_FREXPL:
4202 case BUILT_IN_GAMMA_R:
4203 case BUILT_IN_GAMMAF_R:
4204 case BUILT_IN_GAMMAL_R:
4205 case BUILT_IN_LGAMMA_R:
4206 case BUILT_IN_LGAMMAF_R:
4207 case BUILT_IN_LGAMMAL_R:
4209 case BUILT_IN_MODFF:
4210 case BUILT_IN_MODFL:
4211 case BUILT_IN_REMQUO:
4212 case BUILT_IN_REMQUOF:
4213 case BUILT_IN_REMQUOL:
4216 /* Trampolines are special - they set up passing the static
4218 case BUILT_IN_INIT_TRAMPOLINE:
4220 tree tramp = gimple_call_arg (t, 0);
4221 tree nfunc = gimple_call_arg (t, 1);
4222 tree frame = gimple_call_arg (t, 2);
4224 struct constraint_expr lhs, *rhsp;
4227 varinfo_t nfi = NULL;
4228 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4229 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4232 lhs = get_function_part_constraint (nfi, fi_static_chain);
4233 get_constraint_for (frame, &rhsc);
4234 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4235 process_constraint (new_constraint (lhs, *rhsp));
4236 VEC_free (ce_s, heap, rhsc);
4238 /* Make the frame point to the function for
4239 the trampoline adjustment call. */
4240 get_constraint_for (tramp, &lhsc);
4242 get_constraint_for (nfunc, &rhsc);
4243 process_all_all_constraints (lhsc, rhsc);
4244 VEC_free (ce_s, heap, rhsc);
4245 VEC_free (ce_s, heap, lhsc);
4250 /* Else fallthru to generic handling which will let
4251 the frame escape. */
4254 case BUILT_IN_ADJUST_TRAMPOLINE:
4256 tree tramp = gimple_call_arg (t, 0);
4257 tree res = gimple_call_lhs (t);
4258 if (in_ipa_mode && res)
4260 get_constraint_for (res, &lhsc);
4261 get_constraint_for (tramp, &rhsc);
4263 process_all_all_constraints (lhsc, rhsc);
4264 VEC_free (ce_s, heap, rhsc);
4265 VEC_free (ce_s, heap, lhsc);
4269 /* Variadic argument handling needs to be handled in IPA
4271 case BUILT_IN_VA_START:
4275 tree valist = gimple_call_arg (t, 0);
4276 struct constraint_expr rhs, *lhsp;
4278 /* The va_list gets access to pointers in variadic
4280 fi = lookup_vi_for_tree (cfun->decl);
4281 gcc_assert (fi != NULL);
4282 get_constraint_for (valist, &lhsc);
4284 rhs = get_function_part_constraint (fi, ~0);
4285 rhs.type = ADDRESSOF;
4286 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4287 process_constraint (new_constraint (*lhsp, rhs));
4288 VEC_free (ce_s, heap, lhsc);
4289 /* va_list is clobbered. */
4290 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4295 /* va_end doesn't have any effect that matters. */
4296 case BUILT_IN_VA_END:
4298 /* Alternate return. Simply give up for now. */
4299 case BUILT_IN_RETURN:
4303 || !(fi = get_vi_for_tree (cfun->decl)))
4304 make_constraint_from (get_varinfo (escaped_id), anything_id);
4305 else if (in_ipa_mode
4308 struct constraint_expr lhs, rhs;
4309 lhs = get_function_part_constraint (fi, fi_result);
4310 rhs.var = anything_id;
4313 process_constraint (new_constraint (lhs, rhs));
4317 /* printf-style functions may have hooks to set pointers to
4318 point to somewhere into the generated string. Leave them
4319 for a later excercise... */
4321 /* Fallthru to general call handling. */;
4324 || gimple_call_internal_p (t)
4326 && (!(fi = lookup_vi_for_tree (fndecl))
4327 || !fi->is_fn_info)))
4329 VEC(ce_s, heap) *rhsc = NULL;
4330 int flags = gimple_call_flags (t);
4332 /* Const functions can return their arguments and addresses
4333 of global memory but not of escaped memory. */
4334 if (flags & (ECF_CONST|ECF_NOVOPS))
4336 if (gimple_call_lhs (t))
4337 handle_const_call (t, &rhsc);
4339 /* Pure functions can return addresses in and of memory
4340 reachable from their arguments, but they are not an escape
4341 point for reachable memory of their arguments. */
4342 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4343 handle_pure_call (t, &rhsc);
4345 handle_rhs_call (t, &rhsc);
4346 if (gimple_call_lhs (t))
4347 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4348 VEC_free (ce_s, heap, rhsc);
4355 fi = get_fi_for_callee (t);
4357 /* Assign all the passed arguments to the appropriate incoming
4358 parameters of the function. */
4359 for (j = 0; j < gimple_call_num_args (t); j++)
4361 struct constraint_expr lhs ;
4362 struct constraint_expr *rhsp;
4363 tree arg = gimple_call_arg (t, j);
4365 get_constraint_for_rhs (arg, &rhsc);
4366 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4367 while (VEC_length (ce_s, rhsc) != 0)
4369 rhsp = VEC_last (ce_s, rhsc);
4370 process_constraint (new_constraint (lhs, *rhsp));
4371 VEC_pop (ce_s, rhsc);
4375 /* If we are returning a value, assign it to the result. */
4376 lhsop = gimple_call_lhs (t);
4379 struct constraint_expr rhs;
4380 struct constraint_expr *lhsp;
4382 get_constraint_for (lhsop, &lhsc);
4383 rhs = get_function_part_constraint (fi, fi_result);
4385 && DECL_RESULT (fndecl)
4386 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4388 VEC(ce_s, heap) *tem = NULL;
4389 VEC_safe_push (ce_s, heap, tem, &rhs);
4391 rhs = *VEC_index (ce_s, tem, 0);
4392 VEC_free(ce_s, heap, tem);
4394 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4395 process_constraint (new_constraint (*lhsp, rhs));
4398 /* If we pass the result decl by reference, honor that. */
4401 && DECL_RESULT (fndecl)
4402 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4404 struct constraint_expr lhs;
4405 struct constraint_expr *rhsp;
4407 get_constraint_for_address_of (lhsop, &rhsc);
4408 lhs = get_function_part_constraint (fi, fi_result);
4409 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4410 process_constraint (new_constraint (lhs, *rhsp));
4411 VEC_free (ce_s, heap, rhsc);
4414 /* If we use a static chain, pass it along. */
4415 if (gimple_call_chain (t))
4417 struct constraint_expr lhs;
4418 struct constraint_expr *rhsp;
4420 get_constraint_for (gimple_call_chain (t), &rhsc);
4421 lhs = get_function_part_constraint (fi, fi_static_chain);
4422 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4423 process_constraint (new_constraint (lhs, *rhsp));
4427 /* Otherwise, just a regular assignment statement. Only care about
4428 operations with pointer result, others are dealt with as escape
4429 points if they have pointer operands. */
4430 else if (is_gimple_assign (t))
4432 /* Otherwise, just a regular assignment statement. */
4433 tree lhsop = gimple_assign_lhs (t);
4434 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4436 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4437 do_structure_copy (lhsop, rhsop);
4440 enum tree_code code = gimple_assign_rhs_code (t);
4442 get_constraint_for (lhsop, &lhsc);
4444 if (code == POINTER_PLUS_EXPR)
4445 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4446 gimple_assign_rhs2 (t), &rhsc);
4447 else if (code == BIT_AND_EXPR
4448 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4450 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4451 the pointer. Handle it by offsetting it by UNKNOWN. */
4452 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4455 else if ((CONVERT_EXPR_CODE_P (code)
4456 && !(POINTER_TYPE_P (gimple_expr_type (t))
4457 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4458 || gimple_assign_single_p (t))
4459 get_constraint_for_rhs (rhsop, &rhsc);
4460 else if (truth_value_p (code))
4461 /* Truth value results are not pointer (parts). Or at least
4462 very very unreasonable obfuscation of a part. */
4466 /* All other operations are merges. */
4467 VEC (ce_s, heap) *tmp = NULL;
4468 struct constraint_expr *rhsp;
4470 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4471 for (i = 2; i < gimple_num_ops (t); ++i)
4473 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4474 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4475 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4476 VEC_truncate (ce_s, tmp, 0);
4478 VEC_free (ce_s, heap, tmp);
4480 process_all_all_constraints (lhsc, rhsc);
4482 /* If there is a store to a global variable the rhs escapes. */
4483 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4485 && is_global_var (lhsop)
4487 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4488 make_escape_constraint (rhsop);
4489 /* If this is a conversion of a non-restrict pointer to a
4490 restrict pointer track it with a new heapvar. */
4491 else if (gimple_assign_cast_p (t)
4492 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4493 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4494 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4495 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4496 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4499 /* Handle escapes through return. */
4500 else if (gimple_code (t) == GIMPLE_RETURN
4501 && gimple_return_retval (t) != NULL_TREE)
4505 || !(fi = get_vi_for_tree (cfun->decl)))
4506 make_escape_constraint (gimple_return_retval (t));
4507 else if (in_ipa_mode
4510 struct constraint_expr lhs ;
4511 struct constraint_expr *rhsp;
4514 lhs = get_function_part_constraint (fi, fi_result);
4515 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4516 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4517 process_constraint (new_constraint (lhs, *rhsp));
4520 /* Handle asms conservatively by adding escape constraints to everything. */
4521 else if (gimple_code (t) == GIMPLE_ASM)
4523 unsigned i, noutputs;
4524 const char **oconstraints;
4525 const char *constraint;
4526 bool allows_mem, allows_reg, is_inout;
4528 noutputs = gimple_asm_noutputs (t);
4529 oconstraints = XALLOCAVEC (const char *, noutputs);
4531 for (i = 0; i < noutputs; ++i)
4533 tree link = gimple_asm_output_op (t, i);
4534 tree op = TREE_VALUE (link);
4536 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4537 oconstraints[i] = constraint;
4538 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4539 &allows_reg, &is_inout);
4541 /* A memory constraint makes the address of the operand escape. */
4542 if (!allows_reg && allows_mem)
4543 make_escape_constraint (build_fold_addr_expr (op));
4545 /* The asm may read global memory, so outputs may point to
4546 any global memory. */
4549 VEC(ce_s, heap) *lhsc = NULL;
4550 struct constraint_expr rhsc, *lhsp;
4552 get_constraint_for (op, &lhsc);
4553 rhsc.var = nonlocal_id;
4556 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4557 process_constraint (new_constraint (*lhsp, rhsc));
4558 VEC_free (ce_s, heap, lhsc);
4561 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4563 tree link = gimple_asm_input_op (t, i);
4564 tree op = TREE_VALUE (link);
4566 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4568 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4569 &allows_mem, &allows_reg);
4571 /* A memory constraint makes the address of the operand escape. */
4572 if (!allows_reg && allows_mem)
4573 make_escape_constraint (build_fold_addr_expr (op));
4574 /* Strictly we'd only need the constraint to ESCAPED if
4575 the asm clobbers memory, otherwise using something
4576 along the lines of per-call clobbers/uses would be enough. */
4578 make_escape_constraint (op);
4582 VEC_free (ce_s, heap, rhsc);
4583 VEC_free (ce_s, heap, lhsc);
4587 /* Create a constraint adding to the clobber set of FI the memory
4588 pointed to by PTR. */
4591 process_ipa_clobber (varinfo_t fi, tree ptr)
4593 VEC(ce_s, heap) *ptrc = NULL;
4594 struct constraint_expr *c, lhs;
4596 get_constraint_for_rhs (ptr, &ptrc);
4597 lhs = get_function_part_constraint (fi, fi_clobbers);
4598 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4599 process_constraint (new_constraint (lhs, *c));
4600 VEC_free (ce_s, heap, ptrc);
4603 /* Walk statement T setting up clobber and use constraints according to the
4604 references found in T. This function is a main part of the
4605 IPA constraint builder. */
4608 find_func_clobbers (gimple origt)
4611 VEC(ce_s, heap) *lhsc = NULL;
4612 VEC(ce_s, heap) *rhsc = NULL;
4615 /* Add constraints for clobbered/used in IPA mode.
4616 We are not interested in what automatic variables are clobbered
4617 or used as we only use the information in the caller to which
4618 they do not escape. */
4619 gcc_assert (in_ipa_mode);
4621 /* If the stmt refers to memory in any way it better had a VUSE. */
4622 if (gimple_vuse (t) == NULL_TREE)
4625 /* We'd better have function information for the current function. */
4626 fi = lookup_vi_for_tree (cfun->decl);
4627 gcc_assert (fi != NULL);
4629 /* Account for stores in assignments and calls. */
4630 if (gimple_vdef (t) != NULL_TREE
4631 && gimple_has_lhs (t))
4633 tree lhs = gimple_get_lhs (t);
4635 while (handled_component_p (tem))
4636 tem = TREE_OPERAND (tem, 0);
4638 && !auto_var_in_fn_p (tem, cfun->decl))
4639 || INDIRECT_REF_P (tem)
4640 || (TREE_CODE (tem) == MEM_REF
4641 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4643 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4645 struct constraint_expr lhsc, *rhsp;
4647 lhsc = get_function_part_constraint (fi, fi_clobbers);
4648 get_constraint_for_address_of (lhs, &rhsc);
4649 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4650 process_constraint (new_constraint (lhsc, *rhsp));
4651 VEC_free (ce_s, heap, rhsc);
4655 /* Account for uses in assigments and returns. */
4656 if (gimple_assign_single_p (t)
4657 || (gimple_code (t) == GIMPLE_RETURN
4658 && gimple_return_retval (t) != NULL_TREE))
4660 tree rhs = (gimple_assign_single_p (t)
4661 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4663 while (handled_component_p (tem))
4664 tem = TREE_OPERAND (tem, 0);
4666 && !auto_var_in_fn_p (tem, cfun->decl))
4667 || INDIRECT_REF_P (tem)
4668 || (TREE_CODE (tem) == MEM_REF
4669 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4671 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4673 struct constraint_expr lhs, *rhsp;
4675 lhs = get_function_part_constraint (fi, fi_uses);
4676 get_constraint_for_address_of (rhs, &rhsc);
4677 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4678 process_constraint (new_constraint (lhs, *rhsp));
4679 VEC_free (ce_s, heap, rhsc);
4683 if (is_gimple_call (t))
4685 varinfo_t cfi = NULL;
4686 tree decl = gimple_call_fndecl (t);
4687 struct constraint_expr lhs, rhs;
4690 /* For builtins we do not have separate function info. For those
4691 we do not generate escapes for we have to generate clobbers/uses. */
4693 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4694 switch (DECL_FUNCTION_CODE (decl))
4696 /* The following functions use and clobber memory pointed to
4697 by their arguments. */
4698 case BUILT_IN_STRCPY:
4699 case BUILT_IN_STRNCPY:
4700 case BUILT_IN_BCOPY:
4701 case BUILT_IN_MEMCPY:
4702 case BUILT_IN_MEMMOVE:
4703 case BUILT_IN_MEMPCPY:
4704 case BUILT_IN_STPCPY:
4705 case BUILT_IN_STPNCPY:
4706 case BUILT_IN_STRCAT:
4707 case BUILT_IN_STRNCAT:
4709 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4710 == BUILT_IN_BCOPY ? 1 : 0));
4711 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4712 == BUILT_IN_BCOPY ? 0 : 1));
4714 struct constraint_expr *rhsp, *lhsp;
4715 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4716 lhs = get_function_part_constraint (fi, fi_clobbers);
4717 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4718 process_constraint (new_constraint (lhs, *lhsp));
4719 VEC_free (ce_s, heap, lhsc);
4720 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4721 lhs = get_function_part_constraint (fi, fi_uses);
4722 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4723 process_constraint (new_constraint (lhs, *rhsp));
4724 VEC_free (ce_s, heap, rhsc);
4727 /* The following function clobbers memory pointed to by
4729 case BUILT_IN_MEMSET:
4731 tree dest = gimple_call_arg (t, 0);
4734 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4735 lhs = get_function_part_constraint (fi, fi_clobbers);
4736 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4737 process_constraint (new_constraint (lhs, *lhsp));
4738 VEC_free (ce_s, heap, lhsc);
4741 /* The following functions clobber their second and third
4743 case BUILT_IN_SINCOS:
4744 case BUILT_IN_SINCOSF:
4745 case BUILT_IN_SINCOSL:
4747 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4748 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4751 /* The following functions clobber their second argument. */
4752 case BUILT_IN_FREXP:
4753 case BUILT_IN_FREXPF:
4754 case BUILT_IN_FREXPL:
4755 case BUILT_IN_LGAMMA_R:
4756 case BUILT_IN_LGAMMAF_R:
4757 case BUILT_IN_LGAMMAL_R:
4758 case BUILT_IN_GAMMA_R:
4759 case BUILT_IN_GAMMAF_R:
4760 case BUILT_IN_GAMMAL_R:
4762 case BUILT_IN_MODFF:
4763 case BUILT_IN_MODFL:
4765 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4768 /* The following functions clobber their third argument. */
4769 case BUILT_IN_REMQUO:
4770 case BUILT_IN_REMQUOF:
4771 case BUILT_IN_REMQUOL:
4773 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4776 /* The following functions neither read nor clobber memory. */
4779 /* Trampolines are of no interest to us. */
4780 case BUILT_IN_INIT_TRAMPOLINE:
4781 case BUILT_IN_ADJUST_TRAMPOLINE:
4783 case BUILT_IN_VA_START:
4784 case BUILT_IN_VA_END:
4786 /* printf-style functions may have hooks to set pointers to
4787 point to somewhere into the generated string. Leave them
4788 for a later excercise... */
4790 /* Fallthru to general call handling. */;
4793 /* Parameters passed by value are used. */
4794 lhs = get_function_part_constraint (fi, fi_uses);
4795 for (i = 0; i < gimple_call_num_args (t); i++)
4797 struct constraint_expr *rhsp;
4798 tree arg = gimple_call_arg (t, i);
4800 if (TREE_CODE (arg) == SSA_NAME
4801 || is_gimple_min_invariant (arg))
4804 get_constraint_for_address_of (arg, &rhsc);
4805 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4806 process_constraint (new_constraint (lhs, *rhsp));
4807 VEC_free (ce_s, heap, rhsc);
4810 /* Build constraints for propagating clobbers/uses along the
4812 cfi = get_fi_for_callee (t);
4813 if (cfi->id == anything_id)
4815 if (gimple_vdef (t))
4816 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4818 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4823 /* For callees without function info (that's external functions),
4824 ESCAPED is clobbered and used. */
4825 if (gimple_call_fndecl (t)
4826 && !cfi->is_fn_info)
4830 if (gimple_vdef (t))
4831 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4833 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4835 /* Also honor the call statement use/clobber info. */
4836 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4837 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4839 if ((vi = lookup_call_use_vi (t)) != NULL)
4840 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4845 /* Otherwise the caller clobbers and uses what the callee does.
4846 ??? This should use a new complex constraint that filters
4847 local variables of the callee. */
4848 if (gimple_vdef (t))
4850 lhs = get_function_part_constraint (fi, fi_clobbers);
4851 rhs = get_function_part_constraint (cfi, fi_clobbers);
4852 process_constraint (new_constraint (lhs, rhs));
4854 lhs = get_function_part_constraint (fi, fi_uses);
4855 rhs = get_function_part_constraint (cfi, fi_uses);
4856 process_constraint (new_constraint (lhs, rhs));
4858 else if (gimple_code (t) == GIMPLE_ASM)
4860 /* ??? Ick. We can do better. */
4861 if (gimple_vdef (t))
4862 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4864 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4868 VEC_free (ce_s, heap, rhsc);
4872 /* Find the first varinfo in the same variable as START that overlaps with
4873 OFFSET. Return NULL if we can't find one. */
4876 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4878 /* If the offset is outside of the variable, bail out. */
4879 if (offset >= start->fullsize)
4882 /* If we cannot reach offset from start, lookup the first field
4883 and start from there. */
4884 if (start->offset > offset)
4885 start = lookup_vi_for_tree (start->decl);
4889 /* We may not find a variable in the field list with the actual
4890 offset when when we have glommed a structure to a variable.
4891 In that case, however, offset should still be within the size
4893 if (offset >= start->offset
4894 && (offset - start->offset) < start->size)
4903 /* Find the first varinfo in the same variable as START that overlaps with
4904 OFFSET. If there is no such varinfo the varinfo directly preceding
4905 OFFSET is returned. */
4908 first_or_preceding_vi_for_offset (varinfo_t start,
4909 unsigned HOST_WIDE_INT offset)
4911 /* If we cannot reach offset from start, lookup the first field
4912 and start from there. */
4913 if (start->offset > offset)
4914 start = lookup_vi_for_tree (start->decl);
4916 /* We may not find a variable in the field list with the actual
4917 offset when when we have glommed a structure to a variable.
4918 In that case, however, offset should still be within the size
4920 If we got beyond the offset we look for return the field
4921 directly preceding offset which may be the last field. */
4923 && offset >= start->offset
4924 && !((offset - start->offset) < start->size))
4925 start = start->next;
4931 /* This structure is used during pushing fields onto the fieldstack
4932 to track the offset of the field, since bitpos_of_field gives it
4933 relative to its immediate containing type, and we want it relative
4934 to the ultimate containing object. */
4938 /* Offset from the base of the base containing object to this field. */
4939 HOST_WIDE_INT offset;
4941 /* Size, in bits, of the field. */
4942 unsigned HOST_WIDE_INT size;
4944 unsigned has_unknown_size : 1;
4946 unsigned must_have_pointers : 1;
4948 unsigned may_have_pointers : 1;
4950 unsigned only_restrict_pointers : 1;
4952 typedef struct fieldoff fieldoff_s;
4954 DEF_VEC_O(fieldoff_s);
4955 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4957 /* qsort comparison function for two fieldoff's PA and PB */
4960 fieldoff_compare (const void *pa, const void *pb)
4962 const fieldoff_s *foa = (const fieldoff_s *)pa;
4963 const fieldoff_s *fob = (const fieldoff_s *)pb;
4964 unsigned HOST_WIDE_INT foasize, fobsize;
4966 if (foa->offset < fob->offset)
4968 else if (foa->offset > fob->offset)
4971 foasize = foa->size;
4972 fobsize = fob->size;
4973 if (foasize < fobsize)
4975 else if (foasize > fobsize)
4980 /* Sort a fieldstack according to the field offset and sizes. */
4982 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4984 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
4987 /* Return true if V is a tree that we can have subvars for.
4988 Normally, this is any aggregate type. Also complex
4989 types which are not gimple registers can have subvars. */
4992 var_can_have_subvars (const_tree v)
4994 /* Volatile variables should never have subvars. */
4995 if (TREE_THIS_VOLATILE (v))
4998 /* Non decls or memory tags can never have subvars. */
5002 /* Aggregates without overlapping fields can have subvars. */
5003 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
5009 /* Return true if T is a type that does contain pointers. */
5012 type_must_have_pointers (tree type)
5014 if (POINTER_TYPE_P (type))
5017 if (TREE_CODE (type) == ARRAY_TYPE)
5018 return type_must_have_pointers (TREE_TYPE (type));
5020 /* A function or method can have pointers as arguments, so track
5021 those separately. */
5022 if (TREE_CODE (type) == FUNCTION_TYPE
5023 || TREE_CODE (type) == METHOD_TYPE)
5030 field_must_have_pointers (tree t)
5032 return type_must_have_pointers (TREE_TYPE (t));
5035 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5036 the fields of TYPE onto fieldstack, recording their offsets along
5039 OFFSET is used to keep track of the offset in this entire
5040 structure, rather than just the immediately containing structure.
5041 Returns false if the caller is supposed to handle the field we
5045 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5046 HOST_WIDE_INT offset)
5049 bool empty_p = true;
5051 if (TREE_CODE (type) != RECORD_TYPE)
5054 /* If the vector of fields is growing too big, bail out early.
5055 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5057 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5060 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5061 if (TREE_CODE (field) == FIELD_DECL)
5064 HOST_WIDE_INT foff = bitpos_of_field (field);
5066 if (!var_can_have_subvars (field)
5067 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5068 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5070 else if (!push_fields_onto_fieldstack
5071 (TREE_TYPE (field), fieldstack, offset + foff)
5072 && (DECL_SIZE (field)
5073 && !integer_zerop (DECL_SIZE (field))))
5074 /* Empty structures may have actual size, like in C++. So
5075 see if we didn't push any subfields and the size is
5076 nonzero, push the field onto the stack. */
5081 fieldoff_s *pair = NULL;
5082 bool has_unknown_size = false;
5083 bool must_have_pointers_p;
5085 if (!VEC_empty (fieldoff_s, *fieldstack))
5086 pair = VEC_last (fieldoff_s, *fieldstack);
5088 /* If there isn't anything at offset zero, create sth. */
5090 && offset + foff != 0)
5092 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5094 pair->size = offset + foff;
5095 pair->has_unknown_size = false;
5096 pair->must_have_pointers = false;
5097 pair->may_have_pointers = false;
5098 pair->only_restrict_pointers = false;
5101 if (!DECL_SIZE (field)
5102 || !host_integerp (DECL_SIZE (field), 1))
5103 has_unknown_size = true;
5105 /* If adjacent fields do not contain pointers merge them. */
5106 must_have_pointers_p = field_must_have_pointers (field);
5108 && !has_unknown_size
5109 && !must_have_pointers_p
5110 && !pair->must_have_pointers
5111 && !pair->has_unknown_size
5112 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5114 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5118 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5119 pair->offset = offset + foff;
5120 pair->has_unknown_size = has_unknown_size;
5121 if (!has_unknown_size)
5122 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5125 pair->must_have_pointers = must_have_pointers_p;
5126 pair->may_have_pointers = true;
5127 pair->only_restrict_pointers
5128 = (!has_unknown_size
5129 && POINTER_TYPE_P (TREE_TYPE (field))
5130 && TYPE_RESTRICT (TREE_TYPE (field)));
5140 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5141 if it is a varargs function. */
5144 count_num_arguments (tree decl, bool *is_varargs)
5146 unsigned int num = 0;
5149 /* Capture named arguments for K&R functions. They do not
5150 have a prototype and thus no TYPE_ARG_TYPES. */
5151 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5154 /* Check if the function has variadic arguments. */
5155 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5156 if (TREE_VALUE (t) == void_type_node)
5164 /* Creation function node for DECL, using NAME, and return the index
5165 of the variable we've created for the function. */
5168 create_function_info_for (tree decl, const char *name)
5170 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5171 varinfo_t vi, prev_vi;
5174 bool is_varargs = false;
5175 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5177 /* Create the variable info. */
5179 vi = new_var_info (decl, name);
5182 vi->fullsize = fi_parm_base + num_args;
5184 vi->may_have_pointers = false;
5187 insert_vi_for_tree (vi->decl, vi);
5191 /* Create a variable for things the function clobbers and one for
5192 things the function uses. */
5194 varinfo_t clobbervi, usevi;
5195 const char *newname;
5198 asprintf (&tempname, "%s.clobber", name);
5199 newname = ggc_strdup (tempname);
5202 clobbervi = new_var_info (NULL, newname);
5203 clobbervi->offset = fi_clobbers;
5204 clobbervi->size = 1;
5205 clobbervi->fullsize = vi->fullsize;
5206 clobbervi->is_full_var = true;
5207 clobbervi->is_global_var = false;
5208 gcc_assert (prev_vi->offset < clobbervi->offset);
5209 prev_vi->next = clobbervi;
5210 prev_vi = clobbervi;
5212 asprintf (&tempname, "%s.use", name);
5213 newname = ggc_strdup (tempname);
5216 usevi = new_var_info (NULL, newname);
5217 usevi->offset = fi_uses;
5219 usevi->fullsize = vi->fullsize;
5220 usevi->is_full_var = true;
5221 usevi->is_global_var = false;
5222 gcc_assert (prev_vi->offset < usevi->offset);
5223 prev_vi->next = usevi;
5227 /* And one for the static chain. */
5228 if (fn->static_chain_decl != NULL_TREE)
5231 const char *newname;
5234 asprintf (&tempname, "%s.chain", name);
5235 newname = ggc_strdup (tempname);
5238 chainvi = new_var_info (fn->static_chain_decl, newname);
5239 chainvi->offset = fi_static_chain;
5241 chainvi->fullsize = vi->fullsize;
5242 chainvi->is_full_var = true;
5243 chainvi->is_global_var = false;
5244 gcc_assert (prev_vi->offset < chainvi->offset);
5245 prev_vi->next = chainvi;
5247 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5250 /* Create a variable for the return var. */
5251 if (DECL_RESULT (decl) != NULL
5252 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5255 const char *newname;
5257 tree resultdecl = decl;
5259 if (DECL_RESULT (decl))
5260 resultdecl = DECL_RESULT (decl);
5262 asprintf (&tempname, "%s.result", name);
5263 newname = ggc_strdup (tempname);
5266 resultvi = new_var_info (resultdecl, newname);
5267 resultvi->offset = fi_result;
5269 resultvi->fullsize = vi->fullsize;
5270 resultvi->is_full_var = true;
5271 if (DECL_RESULT (decl))
5272 resultvi->may_have_pointers = true;
5273 gcc_assert (prev_vi->offset < resultvi->offset);
5274 prev_vi->next = resultvi;
5276 if (DECL_RESULT (decl))
5277 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5280 /* Set up variables for each argument. */
5281 arg = DECL_ARGUMENTS (decl);
5282 for (i = 0; i < num_args; i++)
5285 const char *newname;
5287 tree argdecl = decl;
5292 asprintf (&tempname, "%s.arg%d", name, i);
5293 newname = ggc_strdup (tempname);
5296 argvi = new_var_info (argdecl, newname);
5297 argvi->offset = fi_parm_base + i;
5299 argvi->is_full_var = true;
5300 argvi->fullsize = vi->fullsize;
5302 argvi->may_have_pointers = true;
5303 gcc_assert (prev_vi->offset < argvi->offset);
5304 prev_vi->next = argvi;
5308 insert_vi_for_tree (arg, argvi);
5309 arg = DECL_CHAIN (arg);
5313 /* Add one representative for all further args. */
5317 const char *newname;
5321 asprintf (&tempname, "%s.varargs", name);
5322 newname = ggc_strdup (tempname);
5325 /* We need sth that can be pointed to for va_start. */
5326 decl = create_tmp_var_raw (ptr_type_node, name);
5329 argvi = new_var_info (decl, newname);
5330 argvi->offset = fi_parm_base + num_args;
5332 argvi->is_full_var = true;
5333 argvi->is_heap_var = true;
5334 argvi->fullsize = vi->fullsize;
5335 gcc_assert (prev_vi->offset < argvi->offset);
5336 prev_vi->next = argvi;
5344 /* Return true if FIELDSTACK contains fields that overlap.
5345 FIELDSTACK is assumed to be sorted by offset. */
5348 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5350 fieldoff_s *fo = NULL;
5352 HOST_WIDE_INT lastoffset = -1;
5354 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5356 if (fo->offset == lastoffset)
5358 lastoffset = fo->offset;
5363 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5364 This will also create any varinfo structures necessary for fields
5368 create_variable_info_for_1 (tree decl, const char *name)
5370 varinfo_t vi, newvi;
5371 tree decl_type = TREE_TYPE (decl);
5372 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5373 VEC (fieldoff_s,heap) *fieldstack = NULL;
5378 || !host_integerp (declsize, 1))
5380 vi = new_var_info (decl, name);
5384 vi->is_unknown_size_var = true;
5385 vi->is_full_var = true;
5386 vi->may_have_pointers = true;
5390 /* Collect field information. */
5391 if (use_field_sensitive
5392 && var_can_have_subvars (decl)
5393 /* ??? Force us to not use subfields for global initializers
5394 in IPA mode. Else we'd have to parse arbitrary initializers. */
5396 && is_global_var (decl)
5397 && DECL_INITIAL (decl)))
5399 fieldoff_s *fo = NULL;
5400 bool notokay = false;
5403 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5405 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5406 if (fo->has_unknown_size
5413 /* We can't sort them if we have a field with a variable sized type,
5414 which will make notokay = true. In that case, we are going to return
5415 without creating varinfos for the fields anyway, so sorting them is a
5419 sort_fieldstack (fieldstack);
5420 /* Due to some C++ FE issues, like PR 22488, we might end up
5421 what appear to be overlapping fields even though they,
5422 in reality, do not overlap. Until the C++ FE is fixed,
5423 we will simply disable field-sensitivity for these cases. */
5424 notokay = check_for_overlaps (fieldstack);
5428 VEC_free (fieldoff_s, heap, fieldstack);
5431 /* If we didn't end up collecting sub-variables create a full
5432 variable for the decl. */
5433 if (VEC_length (fieldoff_s, fieldstack) <= 1
5434 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5436 vi = new_var_info (decl, name);
5438 vi->may_have_pointers = true;
5439 vi->fullsize = TREE_INT_CST_LOW (declsize);
5440 vi->size = vi->fullsize;
5441 vi->is_full_var = true;
5442 VEC_free (fieldoff_s, heap, fieldstack);
5446 vi = new_var_info (decl, name);
5447 vi->fullsize = TREE_INT_CST_LOW (declsize);
5448 for (i = 0, newvi = vi;
5449 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5450 ++i, newvi = newvi->next)
5452 const char *newname = "NULL";
5457 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5458 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5459 newname = ggc_strdup (tempname);
5462 newvi->name = newname;
5463 newvi->offset = fo->offset;
5464 newvi->size = fo->size;
5465 newvi->fullsize = vi->fullsize;
5466 newvi->may_have_pointers = fo->may_have_pointers;
5467 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5468 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5469 newvi->next = new_var_info (decl, name);
5472 VEC_free (fieldoff_s, heap, fieldstack);
5478 create_variable_info_for (tree decl, const char *name)
5480 varinfo_t vi = create_variable_info_for_1 (decl, name);
5481 unsigned int id = vi->id;
5483 insert_vi_for_tree (decl, vi);
5485 /* Create initial constraints for globals. */
5486 for (; vi; vi = vi->next)
5488 if (!vi->may_have_pointers
5489 || !vi->is_global_var)
5492 /* Mark global restrict qualified pointers. */
5493 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5494 && TYPE_RESTRICT (TREE_TYPE (decl)))
5495 || vi->only_restrict_pointers)
5496 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5498 /* For escaped variables initialize them from nonlocal. */
5500 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5501 make_copy_constraint (vi, nonlocal_id);
5503 /* If this is a global variable with an initializer and we are in
5504 IPA mode generate constraints for it. In non-IPA mode
5505 the initializer from nonlocal is all we need. */
5507 && DECL_INITIAL (decl))
5509 VEC (ce_s, heap) *rhsc = NULL;
5510 struct constraint_expr lhs, *rhsp;
5512 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5516 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5517 process_constraint (new_constraint (lhs, *rhsp));
5518 /* If this is a variable that escapes from the unit
5519 the initializer escapes as well. */
5520 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5522 lhs.var = escaped_id;
5525 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5526 process_constraint (new_constraint (lhs, *rhsp));
5528 VEC_free (ce_s, heap, rhsc);
5535 /* Print out the points-to solution for VAR to FILE. */
5538 dump_solution_for_var (FILE *file, unsigned int var)
5540 varinfo_t vi = get_varinfo (var);
5544 /* Dump the solution for unified vars anyway, this avoids difficulties
5545 in scanning dumps in the testsuite. */
5546 fprintf (file, "%s = { ", vi->name);
5547 vi = get_varinfo (find (var));
5548 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5549 fprintf (file, "%s ", get_varinfo (i)->name);
5550 fprintf (file, "}");
5552 /* But note when the variable was unified. */
5554 fprintf (file, " same as %s", vi->name);
5556 fprintf (file, "\n");
5559 /* Print the points-to solution for VAR to stdout. */
5562 debug_solution_for_var (unsigned int var)
5564 dump_solution_for_var (stdout, var);
5567 /* Create varinfo structures for all of the variables in the
5568 function for intraprocedural mode. */
5571 intra_create_variable_infos (void)
5575 /* For each incoming pointer argument arg, create the constraint ARG
5576 = NONLOCAL or a dummy variable if it is a restrict qualified
5577 passed-by-reference argument. */
5578 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5582 /* For restrict qualified pointers to objects passed by
5583 reference build a real representative for the pointed-to object. */
5584 if (DECL_BY_REFERENCE (t)
5585 && POINTER_TYPE_P (TREE_TYPE (t))
5586 && TYPE_RESTRICT (TREE_TYPE (t)))
5588 struct constraint_expr lhsc, rhsc;
5590 tree heapvar = heapvar_lookup (t, 0);
5591 if (heapvar == NULL_TREE)
5594 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5596 DECL_EXTERNAL (heapvar) = 1;
5597 heapvar_insert (t, 0, heapvar);
5598 ann = get_var_ann (heapvar);
5599 ann->is_heapvar = 1;
5601 if (gimple_referenced_vars (cfun))
5602 add_referenced_var (heapvar);
5603 lhsc.var = get_vi_for_tree (t)->id;
5606 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5607 rhsc.type = ADDRESSOF;
5609 process_constraint (new_constraint (lhsc, rhsc));
5610 vi->is_restrict_var = 1;
5614 for (p = get_vi_for_tree (t); p; p = p->next)
5616 if (p->may_have_pointers)
5617 make_constraint_from (p, nonlocal_id);
5618 if (p->only_restrict_pointers)
5619 make_constraint_from_restrict (p, "PARM_RESTRICT");
5621 if (POINTER_TYPE_P (TREE_TYPE (t))
5622 && TYPE_RESTRICT (TREE_TYPE (t)))
5623 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5626 /* Add a constraint for a result decl that is passed by reference. */
5627 if (DECL_RESULT (cfun->decl)
5628 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5630 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5632 for (p = result_vi; p; p = p->next)
5633 make_constraint_from (p, nonlocal_id);
5636 /* Add a constraint for the incoming static chain parameter. */
5637 if (cfun->static_chain_decl != NULL_TREE)
5639 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5641 for (p = chain_vi; p; p = p->next)
5642 make_constraint_from (p, nonlocal_id);
5646 /* Structure used to put solution bitmaps in a hashtable so they can
5647 be shared among variables with the same points-to set. */
5649 typedef struct shared_bitmap_info
5653 } *shared_bitmap_info_t;
5654 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5656 static htab_t shared_bitmap_table;
5658 /* Hash function for a shared_bitmap_info_t */
5661 shared_bitmap_hash (const void *p)
5663 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5664 return bi->hashcode;
5667 /* Equality function for two shared_bitmap_info_t's. */
5670 shared_bitmap_eq (const void *p1, const void *p2)
5672 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5673 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5674 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5677 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5678 existing instance if there is one, NULL otherwise. */
5681 shared_bitmap_lookup (bitmap pt_vars)
5684 struct shared_bitmap_info sbi;
5686 sbi.pt_vars = pt_vars;
5687 sbi.hashcode = bitmap_hash (pt_vars);
5689 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5690 sbi.hashcode, NO_INSERT);
5694 return ((shared_bitmap_info_t) *slot)->pt_vars;
5698 /* Add a bitmap to the shared bitmap hashtable. */
5701 shared_bitmap_add (bitmap pt_vars)
5704 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5706 sbi->pt_vars = pt_vars;
5707 sbi->hashcode = bitmap_hash (pt_vars);
5709 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5710 sbi->hashcode, INSERT);
5711 gcc_assert (!*slot);
5712 *slot = (void *) sbi;
5716 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5719 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5724 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5726 varinfo_t vi = get_varinfo (i);
5728 /* The only artificial variables that are allowed in a may-alias
5729 set are heap variables. */
5730 if (vi->is_artificial_var && !vi->is_heap_var)
5733 if (TREE_CODE (vi->decl) == VAR_DECL
5734 || TREE_CODE (vi->decl) == PARM_DECL
5735 || TREE_CODE (vi->decl) == RESULT_DECL)
5737 /* If we are in IPA mode we will not recompute points-to
5738 sets after inlining so make sure they stay valid. */
5740 && !DECL_PT_UID_SET_P (vi->decl))
5741 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5743 /* Add the decl to the points-to set. Note that the points-to
5744 set contains global variables. */
5745 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5746 if (vi->is_global_var)
5747 pt->vars_contains_global = true;
5753 /* Compute the points-to solution *PT for the variable VI. */
5756 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5760 bitmap finished_solution;
5764 memset (pt, 0, sizeof (struct pt_solution));
5766 /* This variable may have been collapsed, let's get the real
5768 vi = get_varinfo (find (orig_vi->id));
5770 /* Translate artificial variables into SSA_NAME_PTR_INFO
5772 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5774 varinfo_t vi = get_varinfo (i);
5776 if (vi->is_artificial_var)
5778 if (vi->id == nothing_id)
5780 else if (vi->id == escaped_id)
5783 pt->ipa_escaped = 1;
5787 else if (vi->id == nonlocal_id)
5789 else if (vi->is_heap_var)
5790 /* We represent heapvars in the points-to set properly. */
5792 else if (vi->id == readonly_id)
5795 else if (vi->id == anything_id
5796 || vi->id == integer_id)
5799 if (vi->is_restrict_var)
5800 pt->vars_contains_restrict = true;
5803 /* Instead of doing extra work, simply do not create
5804 elaborate points-to information for pt_anything pointers. */
5806 && (orig_vi->is_artificial_var
5807 || !pt->vars_contains_restrict))
5810 /* Share the final set of variables when possible. */
5811 finished_solution = BITMAP_GGC_ALLOC ();
5812 stats.points_to_sets_created++;
5814 set_uids_in_ptset (finished_solution, vi->solution, pt);
5815 result = shared_bitmap_lookup (finished_solution);
5818 shared_bitmap_add (finished_solution);
5819 pt->vars = finished_solution;
5824 bitmap_clear (finished_solution);
5828 /* Given a pointer variable P, fill in its points-to set. */
5831 find_what_p_points_to (tree p)
5833 struct ptr_info_def *pi;
5837 /* For parameters, get at the points-to set for the actual parm
5839 if (TREE_CODE (p) == SSA_NAME
5840 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5841 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5842 && SSA_NAME_IS_DEFAULT_DEF (p))
5843 lookup_p = SSA_NAME_VAR (p);
5845 vi = lookup_vi_for_tree (lookup_p);
5849 pi = get_ptr_info (p);
5850 find_what_var_points_to (vi, &pi->pt);
5854 /* Query statistics for points-to solutions. */
5857 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5858 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5859 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5860 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5864 dump_pta_stats (FILE *s)
5866 fprintf (s, "\nPTA query stats:\n");
5867 fprintf (s, " pt_solution_includes: "
5868 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5869 HOST_WIDE_INT_PRINT_DEC" queries\n",
5870 pta_stats.pt_solution_includes_no_alias,
5871 pta_stats.pt_solution_includes_no_alias
5872 + pta_stats.pt_solution_includes_may_alias);
5873 fprintf (s, " pt_solutions_intersect: "
5874 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5875 HOST_WIDE_INT_PRINT_DEC" queries\n",
5876 pta_stats.pt_solutions_intersect_no_alias,
5877 pta_stats.pt_solutions_intersect_no_alias
5878 + pta_stats.pt_solutions_intersect_may_alias);
5882 /* Reset the points-to solution *PT to a conservative default
5883 (point to anything). */
5886 pt_solution_reset (struct pt_solution *pt)
5888 memset (pt, 0, sizeof (struct pt_solution));
5889 pt->anything = true;
5892 /* Set the points-to solution *PT to point only to the variables
5893 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5894 global variables and VARS_CONTAINS_RESTRICT specifies whether
5895 it contains restrict tag variables. */
5898 pt_solution_set (struct pt_solution *pt, bitmap vars,
5899 bool vars_contains_global, bool vars_contains_restrict)
5901 memset (pt, 0, sizeof (struct pt_solution));
5903 pt->vars_contains_global = vars_contains_global;
5904 pt->vars_contains_restrict = vars_contains_restrict;
5907 /* Set the points-to solution *PT to point only to the variable VAR. */
5910 pt_solution_set_var (struct pt_solution *pt, tree var)
5912 memset (pt, 0, sizeof (struct pt_solution));
5913 pt->vars = BITMAP_GGC_ALLOC ();
5914 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5915 pt->vars_contains_global = is_global_var (var);
5918 /* Computes the union of the points-to solutions *DEST and *SRC and
5919 stores the result in *DEST. This changes the points-to bitmap
5920 of *DEST and thus may not be used if that might be shared.
5921 The points-to bitmap of *SRC and *DEST will not be shared after
5922 this function if they were not before. */
5925 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5927 dest->anything |= src->anything;
5930 pt_solution_reset (dest);
5934 dest->nonlocal |= src->nonlocal;
5935 dest->escaped |= src->escaped;
5936 dest->ipa_escaped |= src->ipa_escaped;
5937 dest->null |= src->null;
5938 dest->vars_contains_global |= src->vars_contains_global;
5939 dest->vars_contains_restrict |= src->vars_contains_restrict;
5944 dest->vars = BITMAP_GGC_ALLOC ();
5945 bitmap_ior_into (dest->vars, src->vars);
5948 /* Return true if the points-to solution *PT is empty. */
5951 pt_solution_empty_p (struct pt_solution *pt)
5958 && !bitmap_empty_p (pt->vars))
5961 /* If the solution includes ESCAPED, check if that is empty. */
5963 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5966 /* If the solution includes ESCAPED, check if that is empty. */
5968 && !pt_solution_empty_p (&ipa_escaped_pt))
5974 /* Return true if the points-to solution *PT includes global memory. */
5977 pt_solution_includes_global (struct pt_solution *pt)
5981 || pt->vars_contains_global)
5985 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5987 if (pt->ipa_escaped)
5988 return pt_solution_includes_global (&ipa_escaped_pt);
5990 /* ??? This predicate is not correct for the IPA-PTA solution
5991 as we do not properly distinguish between unit escape points
5992 and global variables. */
5993 if (cfun->gimple_df->ipa_pta)
5999 /* Return true if the points-to solution *PT includes the variable
6000 declaration DECL. */
6003 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
6009 && is_global_var (decl))
6013 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
6016 /* If the solution includes ESCAPED, check it. */
6018 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
6021 /* If the solution includes ESCAPED, check it. */
6023 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6030 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6032 bool res = pt_solution_includes_1 (pt, decl);
6034 ++pta_stats.pt_solution_includes_may_alias;
6036 ++pta_stats.pt_solution_includes_no_alias;
6040 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6044 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6046 if (pt1->anything || pt2->anything)
6049 /* If either points to unknown global memory and the other points to
6050 any global memory they alias. */
6053 || pt2->vars_contains_global))
6055 && pt1->vars_contains_global))
6058 /* Check the escaped solution if required. */
6059 if ((pt1->escaped || pt2->escaped)
6060 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6062 /* If both point to escaped memory and that solution
6063 is not empty they alias. */
6064 if (pt1->escaped && pt2->escaped)
6067 /* If either points to escaped memory see if the escaped solution
6068 intersects with the other. */
6070 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6072 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6076 /* Check the escaped solution if required.
6077 ??? Do we need to check the local against the IPA escaped sets? */
6078 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6079 && !pt_solution_empty_p (&ipa_escaped_pt))
6081 /* If both point to escaped memory and that solution
6082 is not empty they alias. */
6083 if (pt1->ipa_escaped && pt2->ipa_escaped)
6086 /* If either points to escaped memory see if the escaped solution
6087 intersects with the other. */
6088 if ((pt1->ipa_escaped
6089 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6090 || (pt2->ipa_escaped
6091 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6095 /* Now both pointers alias if their points-to solution intersects. */
6098 && bitmap_intersect_p (pt1->vars, pt2->vars));
6102 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6104 bool res = pt_solutions_intersect_1 (pt1, pt2);
6106 ++pta_stats.pt_solutions_intersect_may_alias;
6108 ++pta_stats.pt_solutions_intersect_no_alias;
6112 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6113 qualified pointers are possibly based on the same pointer. */
6116 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6117 struct pt_solution *pt2)
6119 /* If we deal with points-to solutions of two restrict qualified
6120 pointers solely rely on the pointed-to variable bitmap intersection.
6121 For two pointers that are based on each other the bitmaps will
6123 if (pt1->vars_contains_restrict
6124 && pt2->vars_contains_restrict)
6126 gcc_assert (pt1->vars && pt2->vars);
6127 return bitmap_intersect_p (pt1->vars, pt2->vars);
6134 /* Dump points-to information to OUTFILE. */
6137 dump_sa_points_to_info (FILE *outfile)
6141 fprintf (outfile, "\nPoints-to sets\n\n");
6143 if (dump_flags & TDF_STATS)
6145 fprintf (outfile, "Stats:\n");
6146 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6147 fprintf (outfile, "Non-pointer vars: %d\n",
6148 stats.nonpointer_vars);
6149 fprintf (outfile, "Statically unified vars: %d\n",
6150 stats.unified_vars_static);
6151 fprintf (outfile, "Dynamically unified vars: %d\n",
6152 stats.unified_vars_dynamic);
6153 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6154 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6155 fprintf (outfile, "Number of implicit edges: %d\n",
6156 stats.num_implicit_edges);
6159 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6161 varinfo_t vi = get_varinfo (i);
6162 if (!vi->may_have_pointers)
6164 dump_solution_for_var (outfile, i);
6169 /* Debug points-to information to stderr. */
6172 debug_sa_points_to_info (void)
6174 dump_sa_points_to_info (stderr);
6178 /* Initialize the always-existing constraint variables for NULL
6179 ANYTHING, READONLY, and INTEGER */
6182 init_base_vars (void)
6184 struct constraint_expr lhs, rhs;
6185 varinfo_t var_anything;
6186 varinfo_t var_nothing;
6187 varinfo_t var_readonly;
6188 varinfo_t var_escaped;
6189 varinfo_t var_nonlocal;
6190 varinfo_t var_storedanything;
6191 varinfo_t var_integer;
6193 /* Create the NULL variable, used to represent that a variable points
6195 var_nothing = new_var_info (NULL_TREE, "NULL");
6196 gcc_assert (var_nothing->id == nothing_id);
6197 var_nothing->is_artificial_var = 1;
6198 var_nothing->offset = 0;
6199 var_nothing->size = ~0;
6200 var_nothing->fullsize = ~0;
6201 var_nothing->is_special_var = 1;
6202 var_nothing->may_have_pointers = 0;
6203 var_nothing->is_global_var = 0;
6205 /* Create the ANYTHING variable, used to represent that a variable
6206 points to some unknown piece of memory. */
6207 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6208 gcc_assert (var_anything->id == anything_id);
6209 var_anything->is_artificial_var = 1;
6210 var_anything->size = ~0;
6211 var_anything->offset = 0;
6212 var_anything->next = NULL;
6213 var_anything->fullsize = ~0;
6214 var_anything->is_special_var = 1;
6216 /* Anything points to anything. This makes deref constraints just
6217 work in the presence of linked list and other p = *p type loops,
6218 by saying that *ANYTHING = ANYTHING. */
6220 lhs.var = anything_id;
6222 rhs.type = ADDRESSOF;
6223 rhs.var = anything_id;
6226 /* This specifically does not use process_constraint because
6227 process_constraint ignores all anything = anything constraints, since all
6228 but this one are redundant. */
6229 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6231 /* Create the READONLY variable, used to represent that a variable
6232 points to readonly memory. */
6233 var_readonly = new_var_info (NULL_TREE, "READONLY");
6234 gcc_assert (var_readonly->id == readonly_id);
6235 var_readonly->is_artificial_var = 1;
6236 var_readonly->offset = 0;
6237 var_readonly->size = ~0;
6238 var_readonly->fullsize = ~0;
6239 var_readonly->next = NULL;
6240 var_readonly->is_special_var = 1;
6242 /* readonly memory points to anything, in order to make deref
6243 easier. In reality, it points to anything the particular
6244 readonly variable can point to, but we don't track this
6247 lhs.var = readonly_id;
6249 rhs.type = ADDRESSOF;
6250 rhs.var = readonly_id; /* FIXME */
6252 process_constraint (new_constraint (lhs, rhs));
6254 /* Create the ESCAPED variable, used to represent the set of escaped
6256 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6257 gcc_assert (var_escaped->id == escaped_id);
6258 var_escaped->is_artificial_var = 1;
6259 var_escaped->offset = 0;
6260 var_escaped->size = ~0;
6261 var_escaped->fullsize = ~0;
6262 var_escaped->is_special_var = 0;
6264 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6266 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6267 gcc_assert (var_nonlocal->id == nonlocal_id);
6268 var_nonlocal->is_artificial_var = 1;
6269 var_nonlocal->offset = 0;
6270 var_nonlocal->size = ~0;
6271 var_nonlocal->fullsize = ~0;
6272 var_nonlocal->is_special_var = 1;
6274 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6276 lhs.var = escaped_id;
6279 rhs.var = escaped_id;
6281 process_constraint (new_constraint (lhs, rhs));
6283 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6284 whole variable escapes. */
6286 lhs.var = escaped_id;
6289 rhs.var = escaped_id;
6290 rhs.offset = UNKNOWN_OFFSET;
6291 process_constraint (new_constraint (lhs, rhs));
6293 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6294 everything pointed to by escaped points to what global memory can
6297 lhs.var = escaped_id;
6300 rhs.var = nonlocal_id;
6302 process_constraint (new_constraint (lhs, rhs));
6304 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6305 global memory may point to global memory and escaped memory. */
6307 lhs.var = nonlocal_id;
6309 rhs.type = ADDRESSOF;
6310 rhs.var = nonlocal_id;
6312 process_constraint (new_constraint (lhs, rhs));
6313 rhs.type = ADDRESSOF;
6314 rhs.var = escaped_id;
6316 process_constraint (new_constraint (lhs, rhs));
6318 /* Create the STOREDANYTHING variable, used to represent the set of
6319 variables stored to *ANYTHING. */
6320 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6321 gcc_assert (var_storedanything->id == storedanything_id);
6322 var_storedanything->is_artificial_var = 1;
6323 var_storedanything->offset = 0;
6324 var_storedanything->size = ~0;
6325 var_storedanything->fullsize = ~0;
6326 var_storedanything->is_special_var = 0;
6328 /* Create the INTEGER variable, used to represent that a variable points
6329 to what an INTEGER "points to". */
6330 var_integer = new_var_info (NULL_TREE, "INTEGER");
6331 gcc_assert (var_integer->id == integer_id);
6332 var_integer->is_artificial_var = 1;
6333 var_integer->size = ~0;
6334 var_integer->fullsize = ~0;
6335 var_integer->offset = 0;
6336 var_integer->next = NULL;
6337 var_integer->is_special_var = 1;
6339 /* INTEGER = ANYTHING, because we don't know where a dereference of
6340 a random integer will point to. */
6342 lhs.var = integer_id;
6344 rhs.type = ADDRESSOF;
6345 rhs.var = anything_id;
6347 process_constraint (new_constraint (lhs, rhs));
6350 /* Initialize things necessary to perform PTA */
6353 init_alias_vars (void)
6355 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6357 bitmap_obstack_initialize (&pta_obstack);
6358 bitmap_obstack_initialize (&oldpta_obstack);
6359 bitmap_obstack_initialize (&predbitmap_obstack);
6361 constraint_pool = create_alloc_pool ("Constraint pool",
6362 sizeof (struct constraint), 30);
6363 variable_info_pool = create_alloc_pool ("Variable info pool",
6364 sizeof (struct variable_info), 30);
6365 constraints = VEC_alloc (constraint_t, heap, 8);
6366 varmap = VEC_alloc (varinfo_t, heap, 8);
6367 vi_for_tree = pointer_map_create ();
6368 call_stmt_vars = pointer_map_create ();
6370 memset (&stats, 0, sizeof (stats));
6371 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6372 shared_bitmap_eq, free);
6376 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6377 predecessor edges. */
6380 remove_preds_and_fake_succs (constraint_graph_t graph)
6384 /* Clear the implicit ref and address nodes from the successor
6386 for (i = 0; i < FIRST_REF_NODE; i++)
6388 if (graph->succs[i])
6389 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6390 FIRST_REF_NODE * 2);
6393 /* Free the successor list for the non-ref nodes. */
6394 for (i = FIRST_REF_NODE; i < graph->size; i++)
6396 if (graph->succs[i])
6397 BITMAP_FREE (graph->succs[i]);
6400 /* Now reallocate the size of the successor list as, and blow away
6401 the predecessor bitmaps. */
6402 graph->size = VEC_length (varinfo_t, varmap);
6403 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6405 free (graph->implicit_preds);
6406 graph->implicit_preds = NULL;
6407 free (graph->preds);
6408 graph->preds = NULL;
6409 bitmap_obstack_release (&predbitmap_obstack);
6412 /* Initialize the heapvar for statement mapping. */
6415 init_alias_heapvars (void)
6417 if (!heapvar_for_stmt)
6418 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6422 /* Delete the heapvar for statement mapping. */
6425 delete_alias_heapvars (void)
6427 if (heapvar_for_stmt)
6428 htab_delete (heapvar_for_stmt);
6429 heapvar_for_stmt = NULL;
6432 /* Solve the constraint set. */
6435 solve_constraints (void)
6437 struct scc_info *si;
6441 "\nCollapsing static cycles and doing variable "
6444 init_graph (VEC_length (varinfo_t, varmap) * 2);
6447 fprintf (dump_file, "Building predecessor graph\n");
6448 build_pred_graph ();
6451 fprintf (dump_file, "Detecting pointer and location "
6453 si = perform_var_substitution (graph);
6456 fprintf (dump_file, "Rewriting constraints and unifying "
6458 rewrite_constraints (graph, si);
6460 build_succ_graph ();
6461 free_var_substitution_info (si);
6463 if (dump_file && (dump_flags & TDF_GRAPH))
6464 dump_constraint_graph (dump_file);
6466 move_complex_constraints (graph);
6469 fprintf (dump_file, "Uniting pointer but not location equivalent "
6471 unite_pointer_equivalences (graph);
6474 fprintf (dump_file, "Finding indirect cycles\n");
6475 find_indirect_cycles (graph);
6477 /* Implicit nodes and predecessors are no longer necessary at this
6479 remove_preds_and_fake_succs (graph);
6482 fprintf (dump_file, "Solving graph\n");
6484 solve_graph (graph);
6487 dump_sa_points_to_info (dump_file);
6490 /* Create points-to sets for the current function. See the comments
6491 at the start of the file for an algorithmic overview. */
6494 compute_points_to_sets (void)
6500 timevar_push (TV_TREE_PTA);
6503 init_alias_heapvars ();
6505 intra_create_variable_infos ();
6507 /* Now walk all statements and build the constraint set. */
6510 gimple_stmt_iterator gsi;
6512 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6514 gimple phi = gsi_stmt (gsi);
6516 if (is_gimple_reg (gimple_phi_result (phi)))
6517 find_func_aliases (phi);
6520 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6522 gimple stmt = gsi_stmt (gsi);
6524 find_func_aliases (stmt);
6530 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6531 dump_constraints (dump_file, 0);
6534 /* From the constraints compute the points-to sets. */
6535 solve_constraints ();
6537 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6538 find_what_var_points_to (get_varinfo (escaped_id),
6539 &cfun->gimple_df->escaped);
6541 /* Make sure the ESCAPED solution (which is used as placeholder in
6542 other solutions) does not reference itself. This simplifies
6543 points-to solution queries. */
6544 cfun->gimple_df->escaped.escaped = 0;
6546 /* Mark escaped HEAP variables as global. */
6547 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6549 && !vi->is_restrict_var
6550 && !vi->is_global_var)
6551 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6552 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6554 /* Compute the points-to sets for pointer SSA_NAMEs. */
6555 for (i = 0; i < num_ssa_names; ++i)
6557 tree ptr = ssa_name (i);
6559 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6560 find_what_p_points_to (ptr);
6563 /* Compute the call-used/clobbered sets. */
6566 gimple_stmt_iterator gsi;
6568 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6570 gimple stmt = gsi_stmt (gsi);
6571 struct pt_solution *pt;
6572 if (!is_gimple_call (stmt))
6575 pt = gimple_call_use_set (stmt);
6576 if (gimple_call_flags (stmt) & ECF_CONST)
6577 memset (pt, 0, sizeof (struct pt_solution));
6578 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6580 find_what_var_points_to (vi, pt);
6581 /* Escaped (and thus nonlocal) variables are always
6582 implicitly used by calls. */
6583 /* ??? ESCAPED can be empty even though NONLOCAL
6590 /* If there is nothing special about this call then
6591 we have made everything that is used also escape. */
6592 *pt = cfun->gimple_df->escaped;
6596 pt = gimple_call_clobber_set (stmt);
6597 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6598 memset (pt, 0, sizeof (struct pt_solution));
6599 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6601 find_what_var_points_to (vi, pt);
6602 /* Escaped (and thus nonlocal) variables are always
6603 implicitly clobbered by calls. */
6604 /* ??? ESCAPED can be empty even though NONLOCAL
6611 /* If there is nothing special about this call then
6612 we have made everything that is used also escape. */
6613 *pt = cfun->gimple_df->escaped;
6619 timevar_pop (TV_TREE_PTA);
6623 /* Delete created points-to sets. */
6626 delete_points_to_sets (void)
6630 htab_delete (shared_bitmap_table);
6631 if (dump_file && (dump_flags & TDF_STATS))
6632 fprintf (dump_file, "Points to sets created:%d\n",
6633 stats.points_to_sets_created);
6635 pointer_map_destroy (vi_for_tree);
6636 pointer_map_destroy (call_stmt_vars);
6637 bitmap_obstack_release (&pta_obstack);
6638 VEC_free (constraint_t, heap, constraints);
6640 for (i = 0; i < graph->size; i++)
6641 VEC_free (constraint_t, heap, graph->complex[i]);
6642 free (graph->complex);
6645 free (graph->succs);
6647 free (graph->pe_rep);
6648 free (graph->indirect_cycles);
6651 VEC_free (varinfo_t, heap, varmap);
6652 free_alloc_pool (variable_info_pool);
6653 free_alloc_pool (constraint_pool);
6657 /* Compute points-to information for every SSA_NAME pointer in the
6658 current function and compute the transitive closure of escaped
6659 variables to re-initialize the call-clobber states of local variables. */
6662 compute_may_aliases (void)
6664 if (cfun->gimple_df->ipa_pta)
6668 fprintf (dump_file, "\nNot re-computing points-to information "
6669 "because IPA points-to information is available.\n\n");
6671 /* But still dump what we have remaining it. */
6672 dump_alias_info (dump_file);
6674 if (dump_flags & TDF_DETAILS)
6675 dump_referenced_vars (dump_file);
6681 /* For each pointer P_i, determine the sets of variables that P_i may
6682 point-to. Compute the reachability set of escaped and call-used
6684 compute_points_to_sets ();
6686 /* Debugging dumps. */
6689 dump_alias_info (dump_file);
6691 if (dump_flags & TDF_DETAILS)
6692 dump_referenced_vars (dump_file);
6695 /* Deallocate memory used by aliasing data structures and the internal
6696 points-to solution. */
6697 delete_points_to_sets ();
6699 gcc_assert (!need_ssa_update_p (cfun));
6705 gate_tree_pta (void)
6707 return flag_tree_pta;
6710 /* A dummy pass to cause points-to information to be computed via
6711 TODO_rebuild_alias. */
6713 struct gimple_opt_pass pass_build_alias =
6718 gate_tree_pta, /* gate */
6722 0, /* static_pass_number */
6723 TV_NONE, /* tv_id */
6724 PROP_cfg | PROP_ssa, /* properties_required */
6725 0, /* properties_provided */
6726 0, /* properties_destroyed */
6727 0, /* todo_flags_start */
6728 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6732 /* A dummy pass to cause points-to information to be computed via
6733 TODO_rebuild_alias. */
6735 struct gimple_opt_pass pass_build_ealias =
6739 "ealias", /* name */
6740 gate_tree_pta, /* gate */
6744 0, /* static_pass_number */
6745 TV_NONE, /* tv_id */
6746 PROP_cfg | PROP_ssa, /* properties_required */
6747 0, /* properties_provided */
6748 0, /* properties_destroyed */
6749 0, /* todo_flags_start */
6750 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6755 /* Return true if we should execute IPA PTA. */
6761 /* Don't bother doing anything if the program has errors. */
6765 /* IPA PTA solutions for ESCAPED. */
6766 struct pt_solution ipa_escaped_pt
6767 = { true, false, false, false, false, false, false, NULL };
6769 /* Execute the driver for IPA PTA. */
6771 ipa_pta_execute (void)
6773 struct cgraph_node *node;
6774 struct varpool_node *var;
6779 init_alias_heapvars ();
6782 /* Build the constraints. */
6783 for (node = cgraph_nodes; node; node = node->next)
6785 struct cgraph_node *alias;
6788 /* Nodes without a body are not interesting. Especially do not
6789 visit clones at this point for now - we get duplicate decls
6790 there for inline clones at least. */
6791 if (!gimple_has_body_p (node->decl)
6795 vi = create_function_info_for (node->decl,
6796 alias_get_name (node->decl));
6798 /* Associate the varinfo node with all aliases. */
6799 for (alias = node->same_body; alias; alias = alias->next)
6800 insert_vi_for_tree (alias->decl, vi);
6803 /* Create constraints for global variables and their initializers. */
6804 for (var = varpool_nodes; var; var = var->next)
6806 struct varpool_node *alias;
6809 vi = get_vi_for_tree (var->decl);
6811 /* Associate the varinfo node with all aliases. */
6812 for (alias = var->extra_name; alias; alias = alias->next)
6813 insert_vi_for_tree (alias->decl, vi);
6819 "Generating constraints for global initializers\n\n");
6820 dump_constraints (dump_file, 0);
6821 fprintf (dump_file, "\n");
6823 from = VEC_length (constraint_t, constraints);
6825 for (node = cgraph_nodes; node; node = node->next)
6827 struct function *func;
6831 /* Nodes without a body are not interesting. */
6832 if (!gimple_has_body_p (node->decl)
6839 "Generating constraints for %s", cgraph_node_name (node));
6840 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6841 fprintf (dump_file, " (%s)",
6842 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6843 fprintf (dump_file, "\n");
6846 func = DECL_STRUCT_FUNCTION (node->decl);
6847 old_func_decl = current_function_decl;
6849 current_function_decl = node->decl;
6851 if (node->local.externally_visible)
6853 /* For externally visible functions use local constraints for
6854 their arguments. For local functions we see all callers
6855 and thus do not need initial constraints for parameters. */
6856 intra_create_variable_infos ();
6858 /* We also need to make function return values escape. Nothing
6859 escapes by returning from main though. */
6860 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6863 fi = lookup_vi_for_tree (node->decl);
6864 rvi = first_vi_for_offset (fi, fi_result);
6865 if (rvi && rvi->offset == fi_result)
6867 struct constraint_expr includes;
6868 struct constraint_expr var;
6869 includes.var = escaped_id;
6870 includes.offset = 0;
6871 includes.type = SCALAR;
6875 process_constraint (new_constraint (includes, var));
6880 /* Build constriants for the function body. */
6881 FOR_EACH_BB_FN (bb, func)
6883 gimple_stmt_iterator gsi;
6885 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6888 gimple phi = gsi_stmt (gsi);
6890 if (is_gimple_reg (gimple_phi_result (phi)))
6891 find_func_aliases (phi);
6894 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6896 gimple stmt = gsi_stmt (gsi);
6898 find_func_aliases (stmt);
6899 find_func_clobbers (stmt);
6903 current_function_decl = old_func_decl;
6908 fprintf (dump_file, "\n");
6909 dump_constraints (dump_file, from);
6910 fprintf (dump_file, "\n");
6912 from = VEC_length (constraint_t, constraints);
6915 /* From the constraints compute the points-to sets. */
6916 solve_constraints ();
6918 /* Compute the global points-to sets for ESCAPED.
6919 ??? Note that the computed escape set is not correct
6920 for the whole unit as we fail to consider graph edges to
6921 externally visible functions. */
6922 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6924 /* Make sure the ESCAPED solution (which is used as placeholder in
6925 other solutions) does not reference itself. This simplifies
6926 points-to solution queries. */
6927 ipa_escaped_pt.ipa_escaped = 0;
6929 /* Assign the points-to sets to the SSA names in the unit. */
6930 for (node = cgraph_nodes; node; node = node->next)
6933 struct function *fn;
6937 struct pt_solution uses, clobbers;
6938 struct cgraph_edge *e;
6940 /* Nodes without a body are not interesting. */
6941 if (!gimple_has_body_p (node->decl)
6945 fn = DECL_STRUCT_FUNCTION (node->decl);
6947 /* Compute the points-to sets for pointer SSA_NAMEs. */
6948 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6951 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6952 find_what_p_points_to (ptr);
6955 /* Compute the call-use and call-clobber sets for all direct calls. */
6956 fi = lookup_vi_for_tree (node->decl);
6957 gcc_assert (fi->is_fn_info);
6958 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6960 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6961 for (e = node->callers; e; e = e->next_caller)
6966 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6967 *gimple_call_use_set (e->call_stmt) = uses;
6970 /* Compute the call-use and call-clobber sets for indirect calls
6971 and calls to external functions. */
6972 FOR_EACH_BB_FN (bb, fn)
6974 gimple_stmt_iterator gsi;
6976 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6978 gimple stmt = gsi_stmt (gsi);
6979 struct pt_solution *pt;
6983 if (!is_gimple_call (stmt))
6986 /* Handle direct calls to external functions. */
6987 decl = gimple_call_fndecl (stmt);
6989 && (!(fi = lookup_vi_for_tree (decl))
6990 || !fi->is_fn_info))
6992 pt = gimple_call_use_set (stmt);
6993 if (gimple_call_flags (stmt) & ECF_CONST)
6994 memset (pt, 0, sizeof (struct pt_solution));
6995 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6997 find_what_var_points_to (vi, pt);
6998 /* Escaped (and thus nonlocal) variables are always
6999 implicitly used by calls. */
7000 /* ??? ESCAPED can be empty even though NONLOCAL
7003 pt->ipa_escaped = 1;
7007 /* If there is nothing special about this call then
7008 we have made everything that is used also escape. */
7009 *pt = ipa_escaped_pt;
7013 pt = gimple_call_clobber_set (stmt);
7014 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
7015 memset (pt, 0, sizeof (struct pt_solution));
7016 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
7018 find_what_var_points_to (vi, pt);
7019 /* Escaped (and thus nonlocal) variables are always
7020 implicitly clobbered by calls. */
7021 /* ??? ESCAPED can be empty even though NONLOCAL
7024 pt->ipa_escaped = 1;
7028 /* If there is nothing special about this call then
7029 we have made everything that is used also escape. */
7030 *pt = ipa_escaped_pt;
7035 /* Handle indirect calls. */
7037 && (fi = get_fi_for_callee (stmt)))
7039 /* We need to accumulate all clobbers/uses of all possible
7041 fi = get_varinfo (find (fi->id));
7042 /* If we cannot constrain the set of functions we'll end up
7043 calling we end up using/clobbering everything. */
7044 if (bitmap_bit_p (fi->solution, anything_id)
7045 || bitmap_bit_p (fi->solution, nonlocal_id)
7046 || bitmap_bit_p (fi->solution, escaped_id))
7048 pt_solution_reset (gimple_call_clobber_set (stmt));
7049 pt_solution_reset (gimple_call_use_set (stmt));
7055 struct pt_solution *uses, *clobbers;
7057 uses = gimple_call_use_set (stmt);
7058 clobbers = gimple_call_clobber_set (stmt);
7059 memset (uses, 0, sizeof (struct pt_solution));
7060 memset (clobbers, 0, sizeof (struct pt_solution));
7061 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7063 struct pt_solution sol;
7065 vi = get_varinfo (i);
7066 if (!vi->is_fn_info)
7068 /* ??? We could be more precise here? */
7070 uses->ipa_escaped = 1;
7071 clobbers->nonlocal = 1;
7072 clobbers->ipa_escaped = 1;
7076 if (!uses->anything)
7078 find_what_var_points_to
7079 (first_vi_for_offset (vi, fi_uses), &sol);
7080 pt_solution_ior_into (uses, &sol);
7082 if (!clobbers->anything)
7084 find_what_var_points_to
7085 (first_vi_for_offset (vi, fi_clobbers), &sol);
7086 pt_solution_ior_into (clobbers, &sol);
7094 fn->gimple_df->ipa_pta = true;
7097 delete_points_to_sets ();
7104 struct simple_ipa_opt_pass pass_ipa_pta =
7109 gate_ipa_pta, /* gate */
7110 ipa_pta_execute, /* execute */
7113 0, /* static_pass_number */
7114 TV_IPA_PTA, /* tv_id */
7115 0, /* properties_required */
7116 0, /* properties_provided */
7117 0, /* properties_destroyed */
7118 0, /* todo_flags_start */
7119 TODO_update_ssa /* todo_flags_finish */
7124 #include "gt-tree-ssa-structalias.h"