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"
31 #include "basic-block.h"
34 #include "tree-flow.h"
35 #include "tree-inline.h"
36 #include "diagnostic.h"
42 #include "tree-pass.h"
44 #include "alloc-pool.h"
45 #include "splay-tree.h"
49 #include "pointer-set.h"
51 /* The idea behind this analyzer is to generate set constraints from the
52 program, then solve the resulting constraints in order to generate the
55 Set constraints are a way of modeling program analysis problems that
56 involve sets. They consist of an inclusion constraint language,
57 describing the variables (each variable is a set) and operations that
58 are involved on the variables, and a set of rules that derive facts
59 from these operations. To solve a system of set constraints, you derive
60 all possible facts under the rules, which gives you the correct sets
63 See "Efficient Field-sensitive pointer analysis for C" by "David
64 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
65 http://citeseer.ist.psu.edu/pearce04efficient.html
67 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
68 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
69 http://citeseer.ist.psu.edu/heintze01ultrafast.html
71 There are three types of real constraint expressions, DEREF,
72 ADDRESSOF, and SCALAR. Each constraint expression consists
73 of a constraint type, a variable, and an offset.
75 SCALAR is a constraint expression type used to represent x, whether
76 it appears on the LHS or the RHS of a statement.
77 DEREF is a constraint expression type used to represent *x, whether
78 it appears on the LHS or the RHS of a statement.
79 ADDRESSOF is a constraint expression used to represent &x, whether
80 it appears on the LHS or the RHS of a statement.
82 Each pointer variable in the program is assigned an integer id, and
83 each field of a structure variable is assigned an integer id as well.
85 Structure variables are linked to their list of fields through a "next
86 field" in each variable that points to the next field in offset
88 Each variable for a structure field has
90 1. "size", that tells the size in bits of that field.
91 2. "fullsize, that tells the size in bits of the entire structure.
92 3. "offset", that tells the offset in bits from the beginning of the
93 structure to this field.
105 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
106 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
107 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
110 In order to solve the system of set constraints, the following is
113 1. Each constraint variable x has a solution set associated with it,
116 2. Constraints are separated into direct, copy, and complex.
117 Direct constraints are ADDRESSOF constraints that require no extra
118 processing, such as P = &Q
119 Copy constraints are those of the form P = Q.
120 Complex constraints are all the constraints involving dereferences
121 and offsets (including offsetted copies).
123 3. All direct constraints of the form P = &Q are processed, such
124 that Q is added to Sol(P)
126 4. All complex constraints for a given constraint variable are stored in a
127 linked list attached to that variable's node.
129 5. A directed graph is built out of the copy constraints. Each
130 constraint variable is a node in the graph, and an edge from
131 Q to P is added for each copy constraint of the form P = Q
133 6. The graph is then walked, and solution sets are
134 propagated along the copy edges, such that an edge from Q to P
135 causes Sol(P) <- Sol(P) union Sol(Q).
137 7. As we visit each node, all complex constraints associated with
138 that node are processed by adding appropriate copy edges to the graph, or the
139 appropriate variables to the solution set.
141 8. The process of walking the graph is iterated until no solution
144 Prior to walking the graph in steps 6 and 7, We perform static
145 cycle elimination on the constraint graph, as well
146 as off-line variable substitution.
148 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
149 on and turned into anything), but isn't. You can just see what offset
150 inside the pointed-to struct it's going to access.
152 TODO: Constant bounded arrays can be handled as if they were structs of the
153 same number of elements.
155 TODO: Modeling heap and incoming pointers becomes much better if we
156 add fields to them as we discover them, which we could do.
158 TODO: We could handle unions, but to be honest, it's probably not
159 worth the pain or slowdown. */
161 /* IPA-PTA optimizations possible.
163 When the indirect function called is ANYTHING we can add disambiguation
164 based on the function signatures (or simply the parameter count which
165 is the varinfo size). We also do not need to consider functions that
166 do not have their address taken.
168 The is_global_var bit which marks escape points is overly conservative
169 in IPA mode. Split it to is_escape_point and is_global_var - only
170 externally visible globals are escape points in IPA mode. This is
171 also needed to fix the pt_solution_includes_global predicate
172 (and thus ptr_deref_may_alias_global_p).
174 The way we introduce DECL_PT_UID to avoid fixing up all points-to
175 sets in the translation unit when we copy a DECL during inlining
176 pessimizes precision. The advantage is that the DECL_PT_UID keeps
177 compile-time and memory usage overhead low - the points-to sets
178 do not grow or get unshared as they would during a fixup phase.
179 An alternative solution is to delay IPA PTA until after all
180 inlining transformations have been applied.
182 The way we propagate clobber/use information isn't optimized.
183 It should use a new complex constraint that properly filters
184 out local variables of the callee (though that would make
185 the sets invalid after inlining). OTOH we might as well
186 admit defeat to WHOPR and simply do all the clobber/use analysis
187 and propagation after PTA finished but before we threw away
188 points-to information for memory variables. WHOPR and PTA
189 do not play along well anyway - the whole constraint solving
190 would need to be done in WPA phase and it will be very interesting
191 to apply the results to local SSA names during LTRANS phase.
193 We probably should compute a per-function unit-ESCAPE solution
194 propagating it simply like the clobber / uses solutions. The
195 solution can go alongside the non-IPA espaced solution and be
196 used to query which vars escape the unit through a function.
198 We never put function decls in points-to sets so we do not
199 keep the set of called functions for indirect calls.
201 And probably more. */
203 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
204 htab_t heapvar_for_stmt;
206 static bool use_field_sensitive = true;
207 static int in_ipa_mode = 0;
209 /* Used for predecessor bitmaps. */
210 static bitmap_obstack predbitmap_obstack;
212 /* Used for points-to sets. */
213 static bitmap_obstack pta_obstack;
215 /* Used for oldsolution members of variables. */
216 static bitmap_obstack oldpta_obstack;
218 /* Used for per-solver-iteration bitmaps. */
219 static bitmap_obstack iteration_obstack;
221 static unsigned int create_variable_info_for (tree, const char *);
222 typedef struct constraint_graph *constraint_graph_t;
223 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
226 typedef struct constraint *constraint_t;
228 DEF_VEC_P(constraint_t);
229 DEF_VEC_ALLOC_P(constraint_t,heap);
231 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
233 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
235 static struct constraint_stats
237 unsigned int total_vars;
238 unsigned int nonpointer_vars;
239 unsigned int unified_vars_static;
240 unsigned int unified_vars_dynamic;
241 unsigned int iterations;
242 unsigned int num_edges;
243 unsigned int num_implicit_edges;
244 unsigned int points_to_sets_created;
249 /* ID of this variable */
252 /* True if this is a variable created by the constraint analysis, such as
253 heap variables and constraints we had to break up. */
254 unsigned int is_artificial_var : 1;
256 /* True if this is a special variable whose solution set should not be
258 unsigned int is_special_var : 1;
260 /* True for variables whose size is not known or variable. */
261 unsigned int is_unknown_size_var : 1;
263 /* True for (sub-)fields that represent a whole variable. */
264 unsigned int is_full_var : 1;
266 /* True if this is a heap variable. */
267 unsigned int is_heap_var : 1;
269 /* True if this is a variable tracking a restrict pointer source. */
270 unsigned int is_restrict_var : 1;
272 /* True if this field may contain pointers. */
273 unsigned int may_have_pointers : 1;
275 /* True if this field has only restrict qualified pointers. */
276 unsigned int only_restrict_pointers : 1;
278 /* True if this represents a global variable. */
279 unsigned int is_global_var : 1;
281 /* True if this represents a IPA function info. */
282 unsigned int is_fn_info : 1;
284 /* A link to the variable for the next field in this structure. */
285 struct variable_info *next;
287 /* Offset of this variable, in bits, from the base variable */
288 unsigned HOST_WIDE_INT offset;
290 /* Size of the variable, in bits. */
291 unsigned HOST_WIDE_INT size;
293 /* Full size of the base variable, in bits. */
294 unsigned HOST_WIDE_INT fullsize;
296 /* Name of this variable */
299 /* Tree that this variable is associated with. */
302 /* Points-to set for this variable. */
305 /* Old points-to set for this variable. */
308 typedef struct variable_info *varinfo_t;
310 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
311 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
312 unsigned HOST_WIDE_INT);
313 static varinfo_t lookup_vi_for_tree (tree);
315 /* Pool of variable info structures. */
316 static alloc_pool variable_info_pool;
318 DEF_VEC_P(varinfo_t);
320 DEF_VEC_ALLOC_P(varinfo_t, heap);
322 /* Table of variable info structures for constraint variables.
323 Indexed directly by variable info id. */
324 static VEC(varinfo_t,heap) *varmap;
326 /* Return the varmap element N */
328 static inline varinfo_t
329 get_varinfo (unsigned int n)
331 return VEC_index (varinfo_t, varmap, n);
334 /* Static IDs for the special variables. */
335 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
336 escaped_id = 3, nonlocal_id = 4,
337 storedanything_id = 5, integer_id = 6 };
339 struct GTY(()) heapvar_map {
341 unsigned HOST_WIDE_INT offset;
345 heapvar_map_eq (const void *p1, const void *p2)
347 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
348 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
349 return (h1->map.base.from == h2->map.base.from
350 && h1->offset == h2->offset);
354 heapvar_map_hash (struct heapvar_map *h)
356 return iterative_hash_host_wide_int (h->offset,
357 htab_hash_pointer (h->map.base.from));
360 /* Lookup a heap var for FROM, and return it if we find one. */
363 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
365 struct heapvar_map *h, in;
366 in.map.base.from = from;
368 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
369 heapvar_map_hash (&in));
375 /* Insert a mapping FROM->TO in the heap var for statement
379 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
381 struct heapvar_map *h;
384 h = GGC_NEW (struct heapvar_map);
385 h->map.base.from = from;
387 h->map.hash = heapvar_map_hash (h);
389 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
390 gcc_assert (*loc == NULL);
391 *(struct heapvar_map **) loc = h;
394 /* Return a new variable info structure consisting for a variable
395 named NAME, and using constraint graph node NODE. Append it
396 to the vector of variable info structures. */
399 new_var_info (tree t, const char *name)
401 unsigned index = VEC_length (varinfo_t, varmap);
402 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
407 /* Vars without decl are artificial and do not have sub-variables. */
408 ret->is_artificial_var = (t == NULL_TREE);
409 ret->is_special_var = false;
410 ret->is_unknown_size_var = false;
411 ret->is_full_var = (t == NULL_TREE);
412 ret->is_heap_var = false;
413 ret->is_restrict_var = false;
414 ret->may_have_pointers = true;
415 ret->only_restrict_pointers = false;
416 ret->is_global_var = (t == NULL_TREE);
417 ret->is_fn_info = false;
419 ret->is_global_var = is_global_var (t);
420 ret->solution = BITMAP_ALLOC (&pta_obstack);
421 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
426 VEC_safe_push (varinfo_t, heap, varmap, ret);
432 /* A map mapping call statements to per-stmt variables for uses
433 and clobbers specific to the call. */
434 struct pointer_map_t *call_stmt_vars;
436 /* Lookup or create the variable for the call statement CALL. */
439 get_call_vi (gimple call)
444 slot_p = pointer_map_insert (call_stmt_vars, call);
446 return (varinfo_t) *slot_p;
448 vi = new_var_info (NULL_TREE, "CALLUSED");
452 vi->is_full_var = true;
454 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
458 vi2->is_full_var = true;
460 *slot_p = (void *) vi;
464 /* Lookup the variable for the call statement CALL representing
465 the uses. Returns NULL if there is nothing special about this call. */
468 lookup_call_use_vi (gimple call)
472 slot_p = pointer_map_contains (call_stmt_vars, call);
474 return (varinfo_t) *slot_p;
479 /* Lookup the variable for the call statement CALL representing
480 the clobbers. Returns NULL if there is nothing special about this call. */
483 lookup_call_clobber_vi (gimple call)
485 varinfo_t uses = lookup_call_use_vi (call);
492 /* Lookup or create the variable for the call statement CALL representing
496 get_call_use_vi (gimple call)
498 return get_call_vi (call);
501 /* Lookup or create the variable for the call statement CALL representing
504 static varinfo_t ATTRIBUTE_UNUSED
505 get_call_clobber_vi (gimple call)
507 return get_call_vi (call)->next;
511 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
513 /* An expression that appears in a constraint. */
515 struct constraint_expr
517 /* Constraint type. */
518 constraint_expr_type type;
520 /* Variable we are referring to in the constraint. */
523 /* Offset, in bits, of this constraint from the beginning of
524 variables it ends up referring to.
526 IOW, in a deref constraint, we would deref, get the result set,
527 then add OFFSET to each member. */
528 HOST_WIDE_INT offset;
531 /* Use 0x8000... as special unknown offset. */
532 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
534 typedef struct constraint_expr ce_s;
536 DEF_VEC_ALLOC_O(ce_s, heap);
537 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool);
538 static void get_constraint_for (tree, VEC(ce_s, heap) **);
539 static void do_deref (VEC (ce_s, heap) **);
541 /* Our set constraints are made up of two constraint expressions, one
544 As described in the introduction, our set constraints each represent an
545 operation between set valued variables.
549 struct constraint_expr lhs;
550 struct constraint_expr rhs;
553 /* List of constraints that we use to build the constraint graph from. */
555 static VEC(constraint_t,heap) *constraints;
556 static alloc_pool constraint_pool;
558 /* The constraint graph is represented as an array of bitmaps
559 containing successor nodes. */
561 struct constraint_graph
563 /* Size of this graph, which may be different than the number of
564 nodes in the variable map. */
567 /* Explicit successors of each node. */
570 /* Implicit predecessors of each node (Used for variable
572 bitmap *implicit_preds;
574 /* Explicit predecessors of each node (Used for variable substitution). */
577 /* Indirect cycle representatives, or -1 if the node has no indirect
579 int *indirect_cycles;
581 /* Representative node for a node. rep[a] == a unless the node has
585 /* Equivalence class representative for a label. This is used for
586 variable substitution. */
589 /* Pointer equivalence label for a node. All nodes with the same
590 pointer equivalence label can be unified together at some point
591 (either during constraint optimization or after the constraint
595 /* Pointer equivalence representative for a label. This is used to
596 handle nodes that are pointer equivalent but not location
597 equivalent. We can unite these once the addressof constraints
598 are transformed into initial points-to sets. */
601 /* Pointer equivalence label for each node, used during variable
603 unsigned int *pointer_label;
605 /* Location equivalence label for each node, used during location
606 equivalence finding. */
607 unsigned int *loc_label;
609 /* Pointed-by set for each node, used during location equivalence
610 finding. This is pointed-by rather than pointed-to, because it
611 is constructed using the predecessor graph. */
614 /* Points to sets for pointer equivalence. This is *not* the actual
615 points-to sets for nodes. */
618 /* Bitmap of nodes where the bit is set if the node is a direct
619 node. Used for variable substitution. */
620 sbitmap direct_nodes;
622 /* Bitmap of nodes where the bit is set if the node is address
623 taken. Used for variable substitution. */
624 bitmap address_taken;
626 /* Vector of complex constraints for each graph node. Complex
627 constraints are those involving dereferences or offsets that are
629 VEC(constraint_t,heap) **complex;
632 static constraint_graph_t graph;
634 /* During variable substitution and the offline version of indirect
635 cycle finding, we create nodes to represent dereferences and
636 address taken constraints. These represent where these start and
638 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
639 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
641 /* Return the representative node for NODE, if NODE has been unioned
643 This function performs path compression along the way to finding
644 the representative. */
647 find (unsigned int node)
649 gcc_assert (node < graph->size);
650 if (graph->rep[node] != node)
651 return graph->rep[node] = find (graph->rep[node]);
655 /* Union the TO and FROM nodes to the TO nodes.
656 Note that at some point in the future, we may want to do
657 union-by-rank, in which case we are going to have to return the
658 node we unified to. */
661 unite (unsigned int to, unsigned int from)
663 gcc_assert (to < graph->size && from < graph->size);
664 if (to != from && graph->rep[from] != to)
666 graph->rep[from] = to;
672 /* Create a new constraint consisting of LHS and RHS expressions. */
675 new_constraint (const struct constraint_expr lhs,
676 const struct constraint_expr rhs)
678 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
684 /* Print out constraint C to FILE. */
687 dump_constraint (FILE *file, constraint_t c)
689 if (c->lhs.type == ADDRESSOF)
691 else if (c->lhs.type == DEREF)
693 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
694 if (c->lhs.offset == UNKNOWN_OFFSET)
695 fprintf (file, " + UNKNOWN");
696 else if (c->lhs.offset != 0)
697 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
698 fprintf (file, " = ");
699 if (c->rhs.type == ADDRESSOF)
701 else if (c->rhs.type == DEREF)
703 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
704 if (c->rhs.offset == UNKNOWN_OFFSET)
705 fprintf (file, " + UNKNOWN");
706 else if (c->rhs.offset != 0)
707 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
708 fprintf (file, "\n");
712 void debug_constraint (constraint_t);
713 void debug_constraints (void);
714 void debug_constraint_graph (void);
715 void debug_solution_for_var (unsigned int);
716 void debug_sa_points_to_info (void);
718 /* Print out constraint C to stderr. */
721 debug_constraint (constraint_t c)
723 dump_constraint (stderr, c);
726 /* Print out all constraints to FILE */
729 dump_constraints (FILE *file, int from)
733 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
734 dump_constraint (file, c);
737 /* Print out all constraints to stderr. */
740 debug_constraints (void)
742 dump_constraints (stderr, 0);
745 /* Print out to FILE the edge in the constraint graph that is created by
746 constraint c. The edge may have a label, depending on the type of
747 constraint that it represents. If complex1, e.g: a = *b, then the label
748 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
749 complex with an offset, e.g: a = b + 8, then the label is "+".
750 Otherwise the edge has no label. */
753 dump_constraint_edge (FILE *file, constraint_t c)
755 if (c->rhs.type != ADDRESSOF)
757 const char *src = get_varinfo (c->rhs.var)->name;
758 const char *dst = get_varinfo (c->lhs.var)->name;
759 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
760 /* Due to preprocessing of constraints, instructions like *a = *b are
761 illegal; thus, we do not have to handle such cases. */
762 if (c->lhs.type == DEREF)
763 fprintf (file, " [ label=\"*=\" ] ;\n");
764 else if (c->rhs.type == DEREF)
765 fprintf (file, " [ label=\"=*\" ] ;\n");
768 /* We must check the case where the constraint is an offset.
769 In this case, it is treated as a complex constraint. */
770 if (c->rhs.offset != c->lhs.offset)
771 fprintf (file, " [ label=\"+\" ] ;\n");
773 fprintf (file, " ;\n");
778 /* Print the constraint graph in dot format. */
781 dump_constraint_graph (FILE *file)
783 unsigned int i=0, size;
786 /* Only print the graph if it has already been initialized: */
790 /* Print the constraints used to produce the constraint graph. The
791 constraints will be printed as comments in the dot file: */
792 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
793 dump_constraints (file, 0);
794 fprintf (file, "*/\n");
796 /* Prints the header of the dot file: */
797 fprintf (file, "\n\n// The constraint graph in dot format:\n");
798 fprintf (file, "strict digraph {\n");
799 fprintf (file, " node [\n shape = box\n ]\n");
800 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
801 fprintf (file, "\n // List of nodes in the constraint graph:\n");
803 /* The next lines print the nodes in the graph. In order to get the
804 number of nodes in the graph, we must choose the minimum between the
805 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
806 yet been initialized, then graph->size == 0, otherwise we must only
807 read nodes that have an entry in VEC (varinfo_t, varmap). */
808 size = VEC_length (varinfo_t, varmap);
809 size = size < graph->size ? size : graph->size;
810 for (i = 0; i < size; i++)
812 const char *name = get_varinfo (graph->rep[i])->name;
813 fprintf (file, " \"%s\" ;\n", name);
816 /* Go over the list of constraints printing the edges in the constraint
818 fprintf (file, "\n // The constraint edges:\n");
819 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
821 dump_constraint_edge (file, c);
823 /* Prints the tail of the dot file. By now, only the closing bracket. */
824 fprintf (file, "}\n\n\n");
827 /* Print out the constraint graph to stderr. */
830 debug_constraint_graph (void)
832 dump_constraint_graph (stderr);
837 The solver is a simple worklist solver, that works on the following
840 sbitmap changed_nodes = all zeroes;
842 For each node that is not already collapsed:
844 set bit in changed nodes
846 while (changed_count > 0)
848 compute topological ordering for constraint graph
850 find and collapse cycles in the constraint graph (updating
851 changed if necessary)
853 for each node (n) in the graph in topological order:
856 Process each complex constraint associated with the node,
857 updating changed if necessary.
859 For each outgoing edge from n, propagate the solution from n to
860 the destination of the edge, updating changed as necessary.
864 /* Return true if two constraint expressions A and B are equal. */
867 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
869 return a.type == b.type && a.var == b.var && a.offset == b.offset;
872 /* Return true if constraint expression A is less than constraint expression
873 B. This is just arbitrary, but consistent, in order to give them an
877 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
879 if (a.type == b.type)
882 return a.offset < b.offset;
884 return a.var < b.var;
887 return a.type < b.type;
890 /* Return true if constraint A is less than constraint B. This is just
891 arbitrary, but consistent, in order to give them an ordering. */
894 constraint_less (const constraint_t a, const constraint_t b)
896 if (constraint_expr_less (a->lhs, b->lhs))
898 else if (constraint_expr_less (b->lhs, a->lhs))
901 return constraint_expr_less (a->rhs, b->rhs);
904 /* Return true if two constraints A and B are equal. */
907 constraint_equal (struct constraint a, struct constraint b)
909 return constraint_expr_equal (a.lhs, b.lhs)
910 && constraint_expr_equal (a.rhs, b.rhs);
914 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
917 constraint_vec_find (VEC(constraint_t,heap) *vec,
918 struct constraint lookfor)
926 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
927 if (place >= VEC_length (constraint_t, vec))
929 found = VEC_index (constraint_t, vec, place);
930 if (!constraint_equal (*found, lookfor))
935 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
938 constraint_set_union (VEC(constraint_t,heap) **to,
939 VEC(constraint_t,heap) **from)
944 for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++)
946 if (constraint_vec_find (*to, *c) == NULL)
948 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
950 VEC_safe_insert (constraint_t, heap, *to, place, c);
955 /* Expands the solution in SET to all sub-fields of variables included.
956 Union the expanded result into RESULT. */
959 solution_set_expand (bitmap result, bitmap set)
965 /* In a first pass record all variables we need to add all
966 sub-fields off. This avoids quadratic behavior. */
967 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
969 varinfo_t v = get_varinfo (j);
970 if (v->is_artificial_var
973 v = lookup_vi_for_tree (v->decl);
975 vars = BITMAP_ALLOC (NULL);
976 bitmap_set_bit (vars, v->id);
979 /* In the second pass now do the addition to the solution and
980 to speed up solving add it to the delta as well. */
983 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
985 varinfo_t v = get_varinfo (j);
986 for (; v != NULL; v = v->next)
987 bitmap_set_bit (result, v->id);
993 /* Take a solution set SET, add OFFSET to each member of the set, and
994 overwrite SET with the result when done. */
997 solution_set_add (bitmap set, HOST_WIDE_INT offset)
999 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1003 /* If the offset is unknown we have to expand the solution to
1005 if (offset == UNKNOWN_OFFSET)
1007 solution_set_expand (set, set);
1011 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1013 varinfo_t vi = get_varinfo (i);
1015 /* If this is a variable with just one field just set its bit
1017 if (vi->is_artificial_var
1018 || vi->is_unknown_size_var
1020 bitmap_set_bit (result, i);
1023 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1025 /* If the offset makes the pointer point to before the
1026 variable use offset zero for the field lookup. */
1028 && fieldoffset > vi->offset)
1032 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1034 bitmap_set_bit (result, vi->id);
1035 /* If the result is not exactly at fieldoffset include the next
1036 field as well. See get_constraint_for_ptr_offset for more
1038 if (vi->offset != fieldoffset
1039 && vi->next != NULL)
1040 bitmap_set_bit (result, vi->next->id);
1044 bitmap_copy (set, result);
1045 BITMAP_FREE (result);
1048 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1052 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1055 return bitmap_ior_into (to, from);
1061 tmp = BITMAP_ALLOC (&iteration_obstack);
1062 bitmap_copy (tmp, from);
1063 solution_set_add (tmp, inc);
1064 res = bitmap_ior_into (to, tmp);
1070 /* Insert constraint C into the list of complex constraints for graph
1074 insert_into_complex (constraint_graph_t graph,
1075 unsigned int var, constraint_t c)
1077 VEC (constraint_t, heap) *complex = graph->complex[var];
1078 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1081 /* Only insert constraints that do not already exist. */
1082 if (place >= VEC_length (constraint_t, complex)
1083 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1084 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1088 /* Condense two variable nodes into a single variable node, by moving
1089 all associated info from SRC to TO. */
1092 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1098 gcc_assert (find (from) == to);
1100 /* Move all complex constraints from src node into to node */
1101 for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
1103 /* In complex constraints for node src, we may have either
1104 a = *src, and *src = a, or an offseted constraint which are
1105 always added to the rhs node's constraints. */
1107 if (c->rhs.type == DEREF)
1109 else if (c->lhs.type == DEREF)
1114 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1115 VEC_free (constraint_t, heap, graph->complex[from]);
1116 graph->complex[from] = NULL;
1120 /* Remove edges involving NODE from GRAPH. */
1123 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1125 if (graph->succs[node])
1126 BITMAP_FREE (graph->succs[node]);
1129 /* Merge GRAPH nodes FROM and TO into node TO. */
1132 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1135 if (graph->indirect_cycles[from] != -1)
1137 /* If we have indirect cycles with the from node, and we have
1138 none on the to node, the to node has indirect cycles from the
1139 from node now that they are unified.
1140 If indirect cycles exist on both, unify the nodes that they
1141 are in a cycle with, since we know they are in a cycle with
1143 if (graph->indirect_cycles[to] == -1)
1144 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1147 /* Merge all the successor edges. */
1148 if (graph->succs[from])
1150 if (!graph->succs[to])
1151 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1152 bitmap_ior_into (graph->succs[to],
1153 graph->succs[from]);
1156 clear_edges_for_node (graph, from);
1160 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1161 it doesn't exist in the graph already. */
1164 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1170 if (!graph->implicit_preds[to])
1171 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1173 if (bitmap_set_bit (graph->implicit_preds[to], from))
1174 stats.num_implicit_edges++;
1177 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1178 it doesn't exist in the graph already.
1179 Return false if the edge already existed, true otherwise. */
1182 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1185 if (!graph->preds[to])
1186 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1187 bitmap_set_bit (graph->preds[to], from);
1190 /* Add a graph edge to GRAPH, going from FROM to TO if
1191 it doesn't exist in the graph already.
1192 Return false if the edge already existed, true otherwise. */
1195 add_graph_edge (constraint_graph_t graph, unsigned int to,
1206 if (!graph->succs[from])
1207 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1208 if (bitmap_set_bit (graph->succs[from], to))
1211 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1219 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1222 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1225 return (graph->succs[dest]
1226 && bitmap_bit_p (graph->succs[dest], src));
1229 /* Initialize the constraint graph structure to contain SIZE nodes. */
1232 init_graph (unsigned int size)
1236 graph = XCNEW (struct constraint_graph);
1238 graph->succs = XCNEWVEC (bitmap, graph->size);
1239 graph->indirect_cycles = XNEWVEC (int, graph->size);
1240 graph->rep = XNEWVEC (unsigned int, graph->size);
1241 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1242 graph->pe = XCNEWVEC (unsigned int, graph->size);
1243 graph->pe_rep = XNEWVEC (int, graph->size);
1245 for (j = 0; j < graph->size; j++)
1248 graph->pe_rep[j] = -1;
1249 graph->indirect_cycles[j] = -1;
1253 /* Build the constraint graph, adding only predecessor edges right now. */
1256 build_pred_graph (void)
1262 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1263 graph->preds = XCNEWVEC (bitmap, graph->size);
1264 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1265 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1266 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1267 graph->points_to = XCNEWVEC (bitmap, graph->size);
1268 graph->eq_rep = XNEWVEC (int, graph->size);
1269 graph->direct_nodes = sbitmap_alloc (graph->size);
1270 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1271 sbitmap_zero (graph->direct_nodes);
1273 for (j = 0; j < FIRST_REF_NODE; j++)
1275 if (!get_varinfo (j)->is_special_var)
1276 SET_BIT (graph->direct_nodes, j);
1279 for (j = 0; j < graph->size; j++)
1280 graph->eq_rep[j] = -1;
1282 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1283 graph->indirect_cycles[j] = -1;
1285 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1287 struct constraint_expr lhs = c->lhs;
1288 struct constraint_expr rhs = c->rhs;
1289 unsigned int lhsvar = lhs.var;
1290 unsigned int rhsvar = rhs.var;
1292 if (lhs.type == DEREF)
1295 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1296 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1298 else if (rhs.type == DEREF)
1301 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1302 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1304 RESET_BIT (graph->direct_nodes, lhsvar);
1306 else if (rhs.type == ADDRESSOF)
1311 if (graph->points_to[lhsvar] == NULL)
1312 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1313 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1315 if (graph->pointed_by[rhsvar] == NULL)
1316 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1317 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1319 /* Implicitly, *x = y */
1320 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1322 /* All related variables are no longer direct nodes. */
1323 RESET_BIT (graph->direct_nodes, rhsvar);
1324 v = get_varinfo (rhsvar);
1325 if (!v->is_full_var)
1327 v = lookup_vi_for_tree (v->decl);
1330 RESET_BIT (graph->direct_nodes, v->id);
1335 bitmap_set_bit (graph->address_taken, rhsvar);
1337 else if (lhsvar > anything_id
1338 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1341 add_pred_graph_edge (graph, lhsvar, rhsvar);
1342 /* Implicitly, *x = *y */
1343 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1344 FIRST_REF_NODE + rhsvar);
1346 else if (lhs.offset != 0 || rhs.offset != 0)
1348 if (rhs.offset != 0)
1349 RESET_BIT (graph->direct_nodes, lhs.var);
1350 else if (lhs.offset != 0)
1351 RESET_BIT (graph->direct_nodes, rhs.var);
1356 /* Build the constraint graph, adding successor edges. */
1359 build_succ_graph (void)
1364 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1366 struct constraint_expr lhs;
1367 struct constraint_expr rhs;
1368 unsigned int lhsvar;
1369 unsigned int rhsvar;
1376 lhsvar = find (lhs.var);
1377 rhsvar = find (rhs.var);
1379 if (lhs.type == DEREF)
1381 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1382 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1384 else if (rhs.type == DEREF)
1386 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1387 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1389 else if (rhs.type == ADDRESSOF)
1392 gcc_assert (find (rhs.var) == rhs.var);
1393 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1395 else if (lhsvar > anything_id
1396 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1398 add_graph_edge (graph, lhsvar, rhsvar);
1402 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1403 receive pointers. */
1404 t = find (storedanything_id);
1405 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1407 if (!TEST_BIT (graph->direct_nodes, i)
1408 && get_varinfo (i)->may_have_pointers)
1409 add_graph_edge (graph, find (i), t);
1412 /* Everything stored to ANYTHING also potentially escapes. */
1413 add_graph_edge (graph, find (escaped_id), t);
1417 /* Changed variables on the last iteration. */
1418 static unsigned int changed_count;
1419 static sbitmap changed;
1421 /* Strongly Connected Component visitation info. */
1428 unsigned int *node_mapping;
1430 VEC(unsigned,heap) *scc_stack;
1434 /* Recursive routine to find strongly connected components in GRAPH.
1435 SI is the SCC info to store the information in, and N is the id of current
1436 graph node we are processing.
1438 This is Tarjan's strongly connected component finding algorithm, as
1439 modified by Nuutila to keep only non-root nodes on the stack.
1440 The algorithm can be found in "On finding the strongly connected
1441 connected components in a directed graph" by Esko Nuutila and Eljas
1442 Soisalon-Soininen, in Information Processing Letters volume 49,
1443 number 1, pages 9-14. */
1446 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1450 unsigned int my_dfs;
1452 SET_BIT (si->visited, n);
1453 si->dfs[n] = si->current_index ++;
1454 my_dfs = si->dfs[n];
1456 /* Visit all the successors. */
1457 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1461 if (i > LAST_REF_NODE)
1465 if (TEST_BIT (si->deleted, w))
1468 if (!TEST_BIT (si->visited, w))
1469 scc_visit (graph, si, w);
1471 unsigned int t = find (w);
1472 unsigned int nnode = find (n);
1473 gcc_assert (nnode == n);
1475 if (si->dfs[t] < si->dfs[nnode])
1476 si->dfs[n] = si->dfs[t];
1480 /* See if any components have been identified. */
1481 if (si->dfs[n] == my_dfs)
1483 if (VEC_length (unsigned, si->scc_stack) > 0
1484 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1486 bitmap scc = BITMAP_ALLOC (NULL);
1487 unsigned int lowest_node;
1490 bitmap_set_bit (scc, n);
1492 while (VEC_length (unsigned, si->scc_stack) != 0
1493 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1495 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1497 bitmap_set_bit (scc, w);
1500 lowest_node = bitmap_first_set_bit (scc);
1501 gcc_assert (lowest_node < FIRST_REF_NODE);
1503 /* Collapse the SCC nodes into a single node, and mark the
1505 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1507 if (i < FIRST_REF_NODE)
1509 if (unite (lowest_node, i))
1510 unify_nodes (graph, lowest_node, i, false);
1514 unite (lowest_node, i);
1515 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1519 SET_BIT (si->deleted, n);
1522 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1525 /* Unify node FROM into node TO, updating the changed count if
1526 necessary when UPDATE_CHANGED is true. */
1529 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1530 bool update_changed)
1533 gcc_assert (to != from && find (to) == to);
1534 if (dump_file && (dump_flags & TDF_DETAILS))
1535 fprintf (dump_file, "Unifying %s to %s\n",
1536 get_varinfo (from)->name,
1537 get_varinfo (to)->name);
1540 stats.unified_vars_dynamic++;
1542 stats.unified_vars_static++;
1544 merge_graph_nodes (graph, to, from);
1545 merge_node_constraints (graph, to, from);
1547 /* Mark TO as changed if FROM was changed. If TO was already marked
1548 as changed, decrease the changed count. */
1550 if (update_changed && TEST_BIT (changed, from))
1552 RESET_BIT (changed, from);
1553 if (!TEST_BIT (changed, to))
1554 SET_BIT (changed, to);
1557 gcc_assert (changed_count > 0);
1561 if (get_varinfo (from)->solution)
1563 /* If the solution changes because of the merging, we need to mark
1564 the variable as changed. */
1565 if (bitmap_ior_into (get_varinfo (to)->solution,
1566 get_varinfo (from)->solution))
1568 if (update_changed && !TEST_BIT (changed, to))
1570 SET_BIT (changed, to);
1575 BITMAP_FREE (get_varinfo (from)->solution);
1576 BITMAP_FREE (get_varinfo (from)->oldsolution);
1578 if (stats.iterations > 0)
1580 BITMAP_FREE (get_varinfo (to)->oldsolution);
1581 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1584 if (valid_graph_edge (graph, to, to))
1586 if (graph->succs[to])
1587 bitmap_clear_bit (graph->succs[to], to);
1591 /* Information needed to compute the topological ordering of a graph. */
1595 /* sbitmap of visited nodes. */
1597 /* Array that stores the topological order of the graph, *in
1599 VEC(unsigned,heap) *topo_order;
1603 /* Initialize and return a topological info structure. */
1605 static struct topo_info *
1606 init_topo_info (void)
1608 size_t size = graph->size;
1609 struct topo_info *ti = XNEW (struct topo_info);
1610 ti->visited = sbitmap_alloc (size);
1611 sbitmap_zero (ti->visited);
1612 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1617 /* Free the topological sort info pointed to by TI. */
1620 free_topo_info (struct topo_info *ti)
1622 sbitmap_free (ti->visited);
1623 VEC_free (unsigned, heap, ti->topo_order);
1627 /* Visit the graph in topological order, and store the order in the
1628 topo_info structure. */
1631 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1637 SET_BIT (ti->visited, n);
1639 if (graph->succs[n])
1640 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1642 if (!TEST_BIT (ti->visited, j))
1643 topo_visit (graph, ti, j);
1646 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1649 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1650 starting solution for y. */
1653 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1656 unsigned int lhs = c->lhs.var;
1658 bitmap sol = get_varinfo (lhs)->solution;
1661 HOST_WIDE_INT roffset = c->rhs.offset;
1663 /* Our IL does not allow this. */
1664 gcc_assert (c->lhs.offset == 0);
1666 /* If the solution of Y contains anything it is good enough to transfer
1668 if (bitmap_bit_p (delta, anything_id))
1670 flag |= bitmap_set_bit (sol, anything_id);
1674 /* If we do not know at with offset the rhs is dereferenced compute
1675 the reachability set of DELTA, conservatively assuming it is
1676 dereferenced at all valid offsets. */
1677 if (roffset == UNKNOWN_OFFSET)
1679 solution_set_expand (delta, delta);
1680 /* No further offset processing is necessary. */
1684 /* For each variable j in delta (Sol(y)), add
1685 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1686 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1688 varinfo_t v = get_varinfo (j);
1689 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1693 fieldoffset = v->offset;
1694 else if (roffset != 0)
1695 v = first_vi_for_offset (v, fieldoffset);
1696 /* If the access is outside of the variable we can ignore it. */
1704 /* Adding edges from the special vars is pointless.
1705 They don't have sets that can change. */
1706 if (get_varinfo (t)->is_special_var)
1707 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1708 /* Merging the solution from ESCAPED needlessly increases
1709 the set. Use ESCAPED as representative instead. */
1710 else if (v->id == escaped_id)
1711 flag |= bitmap_set_bit (sol, escaped_id);
1712 else if (v->may_have_pointers
1713 && add_graph_edge (graph, lhs, t))
1714 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1716 /* If the variable is not exactly at the requested offset
1717 we have to include the next one. */
1718 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1723 fieldoffset = v->offset;
1729 /* If the LHS solution changed, mark the var as changed. */
1732 get_varinfo (lhs)->solution = sol;
1733 if (!TEST_BIT (changed, lhs))
1735 SET_BIT (changed, lhs);
1741 /* Process a constraint C that represents *(x + off) = y using DELTA
1742 as the starting solution for x. */
1745 do_ds_constraint (constraint_t c, bitmap delta)
1747 unsigned int rhs = c->rhs.var;
1748 bitmap sol = get_varinfo (rhs)->solution;
1751 HOST_WIDE_INT loff = c->lhs.offset;
1752 bool escaped_p = false;
1754 /* Our IL does not allow this. */
1755 gcc_assert (c->rhs.offset == 0);
1757 /* If the solution of y contains ANYTHING simply use the ANYTHING
1758 solution. This avoids needlessly increasing the points-to sets. */
1759 if (bitmap_bit_p (sol, anything_id))
1760 sol = get_varinfo (find (anything_id))->solution;
1762 /* If the solution for x contains ANYTHING we have to merge the
1763 solution of y into all pointer variables which we do via
1765 if (bitmap_bit_p (delta, anything_id))
1767 unsigned t = find (storedanything_id);
1768 if (add_graph_edge (graph, t, rhs))
1770 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1772 if (!TEST_BIT (changed, t))
1774 SET_BIT (changed, t);
1782 /* If we do not know at with offset the rhs is dereferenced compute
1783 the reachability set of DELTA, conservatively assuming it is
1784 dereferenced at all valid offsets. */
1785 if (loff == UNKNOWN_OFFSET)
1787 solution_set_expand (delta, delta);
1791 /* For each member j of delta (Sol(x)), add an edge from y to j and
1792 union Sol(y) into Sol(j) */
1793 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1795 varinfo_t v = get_varinfo (j);
1797 HOST_WIDE_INT fieldoffset = v->offset + loff;
1800 fieldoffset = v->offset;
1802 v = first_vi_for_offset (v, fieldoffset);
1803 /* If the access is outside of the variable we can ignore it. */
1809 if (v->may_have_pointers)
1811 /* If v is a global variable then this is an escape point. */
1812 if (v->is_global_var
1815 t = find (escaped_id);
1816 if (add_graph_edge (graph, t, rhs)
1817 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1818 && !TEST_BIT (changed, t))
1820 SET_BIT (changed, t);
1823 /* Enough to let rhs escape once. */
1827 if (v->is_special_var)
1831 if (add_graph_edge (graph, t, rhs)
1832 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1833 && !TEST_BIT (changed, t))
1835 SET_BIT (changed, t);
1840 /* If the variable is not exactly at the requested offset
1841 we have to include the next one. */
1842 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1847 fieldoffset = v->offset;
1853 /* Handle a non-simple (simple meaning requires no iteration),
1854 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1857 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1859 if (c->lhs.type == DEREF)
1861 if (c->rhs.type == ADDRESSOF)
1868 do_ds_constraint (c, delta);
1871 else if (c->rhs.type == DEREF)
1874 if (!(get_varinfo (c->lhs.var)->is_special_var))
1875 do_sd_constraint (graph, c, delta);
1883 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1884 solution = get_varinfo (c->rhs.var)->solution;
1885 tmp = get_varinfo (c->lhs.var)->solution;
1887 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1891 get_varinfo (c->lhs.var)->solution = tmp;
1892 if (!TEST_BIT (changed, c->lhs.var))
1894 SET_BIT (changed, c->lhs.var);
1901 /* Initialize and return a new SCC info structure. */
1903 static struct scc_info *
1904 init_scc_info (size_t size)
1906 struct scc_info *si = XNEW (struct scc_info);
1909 si->current_index = 0;
1910 si->visited = sbitmap_alloc (size);
1911 sbitmap_zero (si->visited);
1912 si->deleted = sbitmap_alloc (size);
1913 sbitmap_zero (si->deleted);
1914 si->node_mapping = XNEWVEC (unsigned int, size);
1915 si->dfs = XCNEWVEC (unsigned int, size);
1917 for (i = 0; i < size; i++)
1918 si->node_mapping[i] = i;
1920 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1924 /* Free an SCC info structure pointed to by SI */
1927 free_scc_info (struct scc_info *si)
1929 sbitmap_free (si->visited);
1930 sbitmap_free (si->deleted);
1931 free (si->node_mapping);
1933 VEC_free (unsigned, heap, si->scc_stack);
1938 /* Find indirect cycles in GRAPH that occur, using strongly connected
1939 components, and note them in the indirect cycles map.
1941 This technique comes from Ben Hardekopf and Calvin Lin,
1942 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1943 Lines of Code", submitted to PLDI 2007. */
1946 find_indirect_cycles (constraint_graph_t graph)
1949 unsigned int size = graph->size;
1950 struct scc_info *si = init_scc_info (size);
1952 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1953 if (!TEST_BIT (si->visited, i) && find (i) == i)
1954 scc_visit (graph, si, i);
1959 /* Compute a topological ordering for GRAPH, and store the result in the
1960 topo_info structure TI. */
1963 compute_topo_order (constraint_graph_t graph,
1964 struct topo_info *ti)
1967 unsigned int size = graph->size;
1969 for (i = 0; i != size; ++i)
1970 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1971 topo_visit (graph, ti, i);
1974 /* Structure used to for hash value numbering of pointer equivalence
1977 typedef struct equiv_class_label
1980 unsigned int equivalence_class;
1982 } *equiv_class_label_t;
1983 typedef const struct equiv_class_label *const_equiv_class_label_t;
1985 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1987 static htab_t pointer_equiv_class_table;
1989 /* A hashtable for mapping a bitmap of labels->location equivalence
1991 static htab_t location_equiv_class_table;
1993 /* Hash function for a equiv_class_label_t */
1996 equiv_class_label_hash (const void *p)
1998 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1999 return ecl->hashcode;
2002 /* Equality function for two equiv_class_label_t's. */
2005 equiv_class_label_eq (const void *p1, const void *p2)
2007 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2008 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2009 return (eql1->hashcode == eql2->hashcode
2010 && bitmap_equal_p (eql1->labels, eql2->labels));
2013 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2017 equiv_class_lookup (htab_t table, bitmap labels)
2020 struct equiv_class_label ecl;
2022 ecl.labels = labels;
2023 ecl.hashcode = bitmap_hash (labels);
2025 slot = htab_find_slot_with_hash (table, &ecl,
2026 ecl.hashcode, NO_INSERT);
2030 return ((equiv_class_label_t) *slot)->equivalence_class;
2034 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2038 equiv_class_add (htab_t table, unsigned int equivalence_class,
2042 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2044 ecl->labels = labels;
2045 ecl->equivalence_class = equivalence_class;
2046 ecl->hashcode = bitmap_hash (labels);
2048 slot = htab_find_slot_with_hash (table, ecl,
2049 ecl->hashcode, INSERT);
2050 gcc_assert (!*slot);
2051 *slot = (void *) ecl;
2054 /* Perform offline variable substitution.
2056 This is a worst case quadratic time way of identifying variables
2057 that must have equivalent points-to sets, including those caused by
2058 static cycles, and single entry subgraphs, in the constraint graph.
2060 The technique is described in "Exploiting Pointer and Location
2061 Equivalence to Optimize Pointer Analysis. In the 14th International
2062 Static Analysis Symposium (SAS), August 2007." It is known as the
2063 "HU" algorithm, and is equivalent to value numbering the collapsed
2064 constraint graph including evaluating unions.
2066 The general method of finding equivalence classes is as follows:
2067 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2068 Initialize all non-REF nodes to be direct nodes.
2069 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2071 For each constraint containing the dereference, we also do the same
2074 We then compute SCC's in the graph and unify nodes in the same SCC,
2077 For each non-collapsed node x:
2078 Visit all unvisited explicit incoming edges.
2079 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2081 Lookup the equivalence class for pts(x).
2082 If we found one, equivalence_class(x) = found class.
2083 Otherwise, equivalence_class(x) = new class, and new_class is
2084 added to the lookup table.
2086 All direct nodes with the same equivalence class can be replaced
2087 with a single representative node.
2088 All unlabeled nodes (label == 0) are not pointers and all edges
2089 involving them can be eliminated.
2090 We perform these optimizations during rewrite_constraints
2092 In addition to pointer equivalence class finding, we also perform
2093 location equivalence class finding. This is the set of variables
2094 that always appear together in points-to sets. We use this to
2095 compress the size of the points-to sets. */
2097 /* Current maximum pointer equivalence class id. */
2098 static int pointer_equiv_class;
2100 /* Current maximum location equivalence class id. */
2101 static int location_equiv_class;
2103 /* Recursive routine to find strongly connected components in GRAPH,
2104 and label it's nodes with DFS numbers. */
2107 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2111 unsigned int my_dfs;
2113 gcc_assert (si->node_mapping[n] == n);
2114 SET_BIT (si->visited, n);
2115 si->dfs[n] = si->current_index ++;
2116 my_dfs = si->dfs[n];
2118 /* Visit all the successors. */
2119 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2121 unsigned int w = si->node_mapping[i];
2123 if (TEST_BIT (si->deleted, w))
2126 if (!TEST_BIT (si->visited, w))
2127 condense_visit (graph, si, w);
2129 unsigned int t = si->node_mapping[w];
2130 unsigned int nnode = si->node_mapping[n];
2131 gcc_assert (nnode == n);
2133 if (si->dfs[t] < si->dfs[nnode])
2134 si->dfs[n] = si->dfs[t];
2138 /* Visit all the implicit predecessors. */
2139 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2141 unsigned int w = si->node_mapping[i];
2143 if (TEST_BIT (si->deleted, w))
2146 if (!TEST_BIT (si->visited, w))
2147 condense_visit (graph, si, w);
2149 unsigned int t = si->node_mapping[w];
2150 unsigned int nnode = si->node_mapping[n];
2151 gcc_assert (nnode == n);
2153 if (si->dfs[t] < si->dfs[nnode])
2154 si->dfs[n] = si->dfs[t];
2158 /* See if any components have been identified. */
2159 if (si->dfs[n] == my_dfs)
2161 while (VEC_length (unsigned, si->scc_stack) != 0
2162 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2164 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2165 si->node_mapping[w] = n;
2167 if (!TEST_BIT (graph->direct_nodes, w))
2168 RESET_BIT (graph->direct_nodes, n);
2170 /* Unify our nodes. */
2171 if (graph->preds[w])
2173 if (!graph->preds[n])
2174 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2175 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2177 if (graph->implicit_preds[w])
2179 if (!graph->implicit_preds[n])
2180 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2181 bitmap_ior_into (graph->implicit_preds[n],
2182 graph->implicit_preds[w]);
2184 if (graph->points_to[w])
2186 if (!graph->points_to[n])
2187 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2188 bitmap_ior_into (graph->points_to[n],
2189 graph->points_to[w]);
2192 SET_BIT (si->deleted, n);
2195 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2198 /* Label pointer equivalences. */
2201 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2205 SET_BIT (si->visited, n);
2207 if (!graph->points_to[n])
2208 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2210 /* Label and union our incoming edges's points to sets. */
2211 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2213 unsigned int w = si->node_mapping[i];
2214 if (!TEST_BIT (si->visited, w))
2215 label_visit (graph, si, w);
2217 /* Skip unused edges */
2218 if (w == n || graph->pointer_label[w] == 0)
2221 if (graph->points_to[w])
2222 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2224 /* Indirect nodes get fresh variables. */
2225 if (!TEST_BIT (graph->direct_nodes, n))
2226 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2228 if (!bitmap_empty_p (graph->points_to[n]))
2230 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2231 graph->points_to[n]);
2234 label = pointer_equiv_class++;
2235 equiv_class_add (pointer_equiv_class_table,
2236 label, graph->points_to[n]);
2238 graph->pointer_label[n] = label;
2242 /* Perform offline variable substitution, discovering equivalence
2243 classes, and eliminating non-pointer variables. */
2245 static struct scc_info *
2246 perform_var_substitution (constraint_graph_t graph)
2249 unsigned int size = graph->size;
2250 struct scc_info *si = init_scc_info (size);
2252 bitmap_obstack_initialize (&iteration_obstack);
2253 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2254 equiv_class_label_eq, free);
2255 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2256 equiv_class_label_eq, free);
2257 pointer_equiv_class = 1;
2258 location_equiv_class = 1;
2260 /* Condense the nodes, which means to find SCC's, count incoming
2261 predecessors, and unite nodes in SCC's. */
2262 for (i = 0; i < FIRST_REF_NODE; i++)
2263 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2264 condense_visit (graph, si, si->node_mapping[i]);
2266 sbitmap_zero (si->visited);
2267 /* Actually the label the nodes for pointer equivalences */
2268 for (i = 0; i < FIRST_REF_NODE; i++)
2269 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2270 label_visit (graph, si, si->node_mapping[i]);
2272 /* Calculate location equivalence labels. */
2273 for (i = 0; i < FIRST_REF_NODE; i++)
2280 if (!graph->pointed_by[i])
2282 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2284 /* Translate the pointed-by mapping for pointer equivalence
2286 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2288 bitmap_set_bit (pointed_by,
2289 graph->pointer_label[si->node_mapping[j]]);
2291 /* The original pointed_by is now dead. */
2292 BITMAP_FREE (graph->pointed_by[i]);
2294 /* Look up the location equivalence label if one exists, or make
2296 label = equiv_class_lookup (location_equiv_class_table,
2300 label = location_equiv_class++;
2301 equiv_class_add (location_equiv_class_table,
2306 if (dump_file && (dump_flags & TDF_DETAILS))
2307 fprintf (dump_file, "Found location equivalence for node %s\n",
2308 get_varinfo (i)->name);
2309 BITMAP_FREE (pointed_by);
2311 graph->loc_label[i] = label;
2315 if (dump_file && (dump_flags & TDF_DETAILS))
2316 for (i = 0; i < FIRST_REF_NODE; i++)
2318 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2320 "Equivalence classes for %s node id %d:%s are pointer: %d"
2322 direct_node ? "Direct node" : "Indirect node", i,
2323 get_varinfo (i)->name,
2324 graph->pointer_label[si->node_mapping[i]],
2325 graph->loc_label[si->node_mapping[i]]);
2328 /* Quickly eliminate our non-pointer variables. */
2330 for (i = 0; i < FIRST_REF_NODE; i++)
2332 unsigned int node = si->node_mapping[i];
2334 if (graph->pointer_label[node] == 0)
2336 if (dump_file && (dump_flags & TDF_DETAILS))
2338 "%s is a non-pointer variable, eliminating edges.\n",
2339 get_varinfo (node)->name);
2340 stats.nonpointer_vars++;
2341 clear_edges_for_node (graph, node);
2348 /* Free information that was only necessary for variable
2352 free_var_substitution_info (struct scc_info *si)
2355 free (graph->pointer_label);
2356 free (graph->loc_label);
2357 free (graph->pointed_by);
2358 free (graph->points_to);
2359 free (graph->eq_rep);
2360 sbitmap_free (graph->direct_nodes);
2361 htab_delete (pointer_equiv_class_table);
2362 htab_delete (location_equiv_class_table);
2363 bitmap_obstack_release (&iteration_obstack);
2366 /* Return an existing node that is equivalent to NODE, which has
2367 equivalence class LABEL, if one exists. Return NODE otherwise. */
2370 find_equivalent_node (constraint_graph_t graph,
2371 unsigned int node, unsigned int label)
2373 /* If the address version of this variable is unused, we can
2374 substitute it for anything else with the same label.
2375 Otherwise, we know the pointers are equivalent, but not the
2376 locations, and we can unite them later. */
2378 if (!bitmap_bit_p (graph->address_taken, node))
2380 gcc_assert (label < graph->size);
2382 if (graph->eq_rep[label] != -1)
2384 /* Unify the two variables since we know they are equivalent. */
2385 if (unite (graph->eq_rep[label], node))
2386 unify_nodes (graph, graph->eq_rep[label], node, false);
2387 return graph->eq_rep[label];
2391 graph->eq_rep[label] = node;
2392 graph->pe_rep[label] = node;
2397 gcc_assert (label < graph->size);
2398 graph->pe[node] = label;
2399 if (graph->pe_rep[label] == -1)
2400 graph->pe_rep[label] = node;
2406 /* Unite pointer equivalent but not location equivalent nodes in
2407 GRAPH. This may only be performed once variable substitution is
2411 unite_pointer_equivalences (constraint_graph_t graph)
2415 /* Go through the pointer equivalences and unite them to their
2416 representative, if they aren't already. */
2417 for (i = 0; i < FIRST_REF_NODE; i++)
2419 unsigned int label = graph->pe[i];
2422 int label_rep = graph->pe_rep[label];
2424 if (label_rep == -1)
2427 label_rep = find (label_rep);
2428 if (label_rep >= 0 && unite (label_rep, find (i)))
2429 unify_nodes (graph, label_rep, i, false);
2434 /* Move complex constraints to the GRAPH nodes they belong to. */
2437 move_complex_constraints (constraint_graph_t graph)
2442 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2446 struct constraint_expr lhs = c->lhs;
2447 struct constraint_expr rhs = c->rhs;
2449 if (lhs.type == DEREF)
2451 insert_into_complex (graph, lhs.var, c);
2453 else if (rhs.type == DEREF)
2455 if (!(get_varinfo (lhs.var)->is_special_var))
2456 insert_into_complex (graph, rhs.var, c);
2458 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2459 && (lhs.offset != 0 || rhs.offset != 0))
2461 insert_into_complex (graph, rhs.var, c);
2468 /* Optimize and rewrite complex constraints while performing
2469 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2470 result of perform_variable_substitution. */
2473 rewrite_constraints (constraint_graph_t graph,
2474 struct scc_info *si)
2480 for (j = 0; j < graph->size; j++)
2481 gcc_assert (find (j) == j);
2483 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2485 struct constraint_expr lhs = c->lhs;
2486 struct constraint_expr rhs = c->rhs;
2487 unsigned int lhsvar = find (lhs.var);
2488 unsigned int rhsvar = find (rhs.var);
2489 unsigned int lhsnode, rhsnode;
2490 unsigned int lhslabel, rhslabel;
2492 lhsnode = si->node_mapping[lhsvar];
2493 rhsnode = si->node_mapping[rhsvar];
2494 lhslabel = graph->pointer_label[lhsnode];
2495 rhslabel = graph->pointer_label[rhsnode];
2497 /* See if it is really a non-pointer variable, and if so, ignore
2501 if (dump_file && (dump_flags & TDF_DETAILS))
2504 fprintf (dump_file, "%s is a non-pointer variable,"
2505 "ignoring constraint:",
2506 get_varinfo (lhs.var)->name);
2507 dump_constraint (dump_file, c);
2509 VEC_replace (constraint_t, constraints, i, NULL);
2515 if (dump_file && (dump_flags & TDF_DETAILS))
2518 fprintf (dump_file, "%s is a non-pointer variable,"
2519 "ignoring constraint:",
2520 get_varinfo (rhs.var)->name);
2521 dump_constraint (dump_file, c);
2523 VEC_replace (constraint_t, constraints, i, NULL);
2527 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2528 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2529 c->lhs.var = lhsvar;
2530 c->rhs.var = rhsvar;
2535 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2536 part of an SCC, false otherwise. */
2539 eliminate_indirect_cycles (unsigned int node)
2541 if (graph->indirect_cycles[node] != -1
2542 && !bitmap_empty_p (get_varinfo (node)->solution))
2545 VEC(unsigned,heap) *queue = NULL;
2547 unsigned int to = find (graph->indirect_cycles[node]);
2550 /* We can't touch the solution set and call unify_nodes
2551 at the same time, because unify_nodes is going to do
2552 bitmap unions into it. */
2554 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2556 if (find (i) == i && i != to)
2559 VEC_safe_push (unsigned, heap, queue, i);
2564 VEC_iterate (unsigned, queue, queuepos, i);
2567 unify_nodes (graph, to, i, true);
2569 VEC_free (unsigned, heap, queue);
2575 /* Solve the constraint graph GRAPH using our worklist solver.
2576 This is based on the PW* family of solvers from the "Efficient Field
2577 Sensitive Pointer Analysis for C" paper.
2578 It works by iterating over all the graph nodes, processing the complex
2579 constraints and propagating the copy constraints, until everything stops
2580 changed. This corresponds to steps 6-8 in the solving list given above. */
2583 solve_graph (constraint_graph_t graph)
2585 unsigned int size = graph->size;
2590 changed = sbitmap_alloc (size);
2591 sbitmap_zero (changed);
2593 /* Mark all initial non-collapsed nodes as changed. */
2594 for (i = 0; i < size; i++)
2596 varinfo_t ivi = get_varinfo (i);
2597 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2598 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2599 || VEC_length (constraint_t, graph->complex[i]) > 0))
2601 SET_BIT (changed, i);
2606 /* Allocate a bitmap to be used to store the changed bits. */
2607 pts = BITMAP_ALLOC (&pta_obstack);
2609 while (changed_count > 0)
2612 struct topo_info *ti = init_topo_info ();
2615 bitmap_obstack_initialize (&iteration_obstack);
2617 compute_topo_order (graph, ti);
2619 while (VEC_length (unsigned, ti->topo_order) != 0)
2622 i = VEC_pop (unsigned, ti->topo_order);
2624 /* If this variable is not a representative, skip it. */
2628 /* In certain indirect cycle cases, we may merge this
2629 variable to another. */
2630 if (eliminate_indirect_cycles (i) && find (i) != i)
2633 /* If the node has changed, we need to process the
2634 complex constraints and outgoing edges again. */
2635 if (TEST_BIT (changed, i))
2640 VEC(constraint_t,heap) *complex = graph->complex[i];
2641 bool solution_empty;
2643 RESET_BIT (changed, i);
2646 /* Compute the changed set of solution bits. */
2647 bitmap_and_compl (pts, get_varinfo (i)->solution,
2648 get_varinfo (i)->oldsolution);
2650 if (bitmap_empty_p (pts))
2653 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2655 solution = get_varinfo (i)->solution;
2656 solution_empty = bitmap_empty_p (solution);
2658 /* Process the complex constraints */
2659 for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++)
2661 /* XXX: This is going to unsort the constraints in
2662 some cases, which will occasionally add duplicate
2663 constraints during unification. This does not
2664 affect correctness. */
2665 c->lhs.var = find (c->lhs.var);
2666 c->rhs.var = find (c->rhs.var);
2668 /* The only complex constraint that can change our
2669 solution to non-empty, given an empty solution,
2670 is a constraint where the lhs side is receiving
2671 some set from elsewhere. */
2672 if (!solution_empty || c->lhs.type != DEREF)
2673 do_complex_constraint (graph, c, pts);
2676 solution_empty = bitmap_empty_p (solution);
2678 if (!solution_empty)
2681 unsigned eff_escaped_id = find (escaped_id);
2683 /* Propagate solution to all successors. */
2684 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2690 unsigned int to = find (j);
2691 tmp = get_varinfo (to)->solution;
2694 /* Don't try to propagate to ourselves. */
2698 /* If we propagate from ESCAPED use ESCAPED as
2700 if (i == eff_escaped_id)
2701 flag = bitmap_set_bit (tmp, escaped_id);
2703 flag = set_union_with_increment (tmp, pts, 0);
2707 get_varinfo (to)->solution = tmp;
2708 if (!TEST_BIT (changed, to))
2710 SET_BIT (changed, to);
2718 free_topo_info (ti);
2719 bitmap_obstack_release (&iteration_obstack);
2723 sbitmap_free (changed);
2724 bitmap_obstack_release (&oldpta_obstack);
2727 /* Map from trees to variable infos. */
2728 static struct pointer_map_t *vi_for_tree;
2731 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2734 insert_vi_for_tree (tree t, varinfo_t vi)
2736 void **slot = pointer_map_insert (vi_for_tree, t);
2738 gcc_assert (*slot == NULL);
2742 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2743 exist in the map, return NULL, otherwise, return the varinfo we found. */
2746 lookup_vi_for_tree (tree t)
2748 void **slot = pointer_map_contains (vi_for_tree, t);
2752 return (varinfo_t) *slot;
2755 /* Return a printable name for DECL */
2758 alias_get_name (tree decl)
2762 int num_printed = 0;
2764 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2765 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2767 res= get_name (decl);
2775 if (TREE_CODE (decl) == SSA_NAME)
2777 num_printed = asprintf (&temp, "%s_%u",
2778 alias_get_name (SSA_NAME_VAR (decl)),
2779 SSA_NAME_VERSION (decl));
2781 else if (DECL_P (decl))
2783 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2785 if (num_printed > 0)
2787 res = ggc_strdup (temp);
2793 /* Find the variable id for tree T in the map.
2794 If T doesn't exist in the map, create an entry for it and return it. */
2797 get_vi_for_tree (tree t)
2799 void **slot = pointer_map_contains (vi_for_tree, t);
2801 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2803 return (varinfo_t) *slot;
2806 /* Get a scalar constraint expression for a new temporary variable. */
2808 static struct constraint_expr
2809 new_scalar_tmp_constraint_exp (const char *name)
2811 struct constraint_expr tmp;
2814 vi = new_var_info (NULL_TREE, name);
2818 vi->is_full_var = 1;
2827 /* Get a constraint expression vector from an SSA_VAR_P node.
2828 If address_p is true, the result will be taken its address of. */
2831 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2833 struct constraint_expr cexpr;
2836 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2837 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2839 /* For parameters, get at the points-to set for the actual parm
2841 if (TREE_CODE (t) == SSA_NAME
2842 && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2843 && SSA_NAME_IS_DEFAULT_DEF (t))
2845 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2849 vi = get_vi_for_tree (t);
2851 cexpr.type = SCALAR;
2853 /* If we determine the result is "anything", and we know this is readonly,
2854 say it points to readonly memory instead. */
2855 if (cexpr.var == anything_id && TREE_READONLY (t))
2858 cexpr.type = ADDRESSOF;
2859 cexpr.var = readonly_id;
2862 /* If we are not taking the address of the constraint expr, add all
2863 sub-fiels of the variable as well. */
2865 && !vi->is_full_var)
2867 for (; vi; vi = vi->next)
2870 VEC_safe_push (ce_s, heap, *results, &cexpr);
2875 VEC_safe_push (ce_s, heap, *results, &cexpr);
2878 /* Process constraint T, performing various simplifications and then
2879 adding it to our list of overall constraints. */
2882 process_constraint (constraint_t t)
2884 struct constraint_expr rhs = t->rhs;
2885 struct constraint_expr lhs = t->lhs;
2887 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2888 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2890 /* If we didn't get any useful constraint from the lhs we get
2891 &ANYTHING as fallback from get_constraint_for. Deal with
2892 it here by turning it into *ANYTHING. */
2893 if (lhs.type == ADDRESSOF
2894 && lhs.var == anything_id)
2897 /* ADDRESSOF on the lhs is invalid. */
2898 gcc_assert (lhs.type != ADDRESSOF);
2900 /* We shouldn't add constraints from things that cannot have pointers.
2901 It's not completely trivial to avoid in the callers, so do it here. */
2902 if (rhs.type != ADDRESSOF
2903 && !get_varinfo (rhs.var)->may_have_pointers)
2906 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2907 if (!get_varinfo (lhs.var)->may_have_pointers)
2910 /* This can happen in our IR with things like n->a = *p */
2911 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2913 /* Split into tmp = *rhs, *lhs = tmp */
2914 struct constraint_expr tmplhs;
2915 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2916 process_constraint (new_constraint (tmplhs, rhs));
2917 process_constraint (new_constraint (lhs, tmplhs));
2919 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2921 /* Split into tmp = &rhs, *lhs = tmp */
2922 struct constraint_expr tmplhs;
2923 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2924 process_constraint (new_constraint (tmplhs, rhs));
2925 process_constraint (new_constraint (lhs, tmplhs));
2929 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2930 VEC_safe_push (constraint_t, heap, constraints, t);
2934 /* Return true if T is a type that could contain pointers. */
2937 type_could_have_pointers (tree type)
2939 if (POINTER_TYPE_P (type))
2942 if (TREE_CODE (type) == ARRAY_TYPE)
2943 return type_could_have_pointers (TREE_TYPE (type));
2945 /* A function or method can consume pointers.
2946 ??? We could be more precise here. */
2947 if (TREE_CODE (type) == FUNCTION_TYPE
2948 || TREE_CODE (type) == METHOD_TYPE)
2951 return AGGREGATE_TYPE_P (type);
2954 /* Return true if T is a variable of a type that could contain
2958 could_have_pointers (tree t)
2960 return (((TREE_CODE (t) == VAR_DECL
2961 || TREE_CODE (t) == PARM_DECL
2962 || TREE_CODE (t) == RESULT_DECL)
2963 && (TREE_PUBLIC (t) || DECL_EXTERNAL (t) || TREE_ADDRESSABLE (t)))
2964 || type_could_have_pointers (TREE_TYPE (t)));
2967 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2970 static HOST_WIDE_INT
2971 bitpos_of_field (const tree fdecl)
2974 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2975 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2978 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2979 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2983 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2984 resulting constraint expressions in *RESULTS. */
2987 get_constraint_for_ptr_offset (tree ptr, tree offset,
2988 VEC (ce_s, heap) **results)
2990 struct constraint_expr c;
2992 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2994 /* If we do not do field-sensitive PTA adding offsets to pointers
2995 does not change the points-to solution. */
2996 if (!use_field_sensitive)
2998 get_constraint_for (ptr, results);
3002 /* If the offset is not a non-negative integer constant that fits
3003 in a HOST_WIDE_INT, we have to fall back to a conservative
3004 solution which includes all sub-fields of all pointed-to
3005 variables of ptr. */
3006 if (offset == NULL_TREE
3007 || !host_integerp (offset, 0))
3008 rhsoffset = UNKNOWN_OFFSET;
3011 /* Make sure the bit-offset also fits. */
3012 rhsunitoffset = TREE_INT_CST_LOW (offset);
3013 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
3014 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
3015 rhsoffset = UNKNOWN_OFFSET;
3018 get_constraint_for (ptr, results);
3022 /* As we are eventually appending to the solution do not use
3023 VEC_iterate here. */
3024 n = VEC_length (ce_s, *results);
3025 for (j = 0; j < n; j++)
3028 c = *VEC_index (ce_s, *results, j);
3029 curr = get_varinfo (c.var);
3031 if (c.type == ADDRESSOF
3032 /* If this varinfo represents a full variable just use it. */
3033 && curr->is_full_var)
3035 else if (c.type == ADDRESSOF
3036 /* If we do not know the offset add all subfields. */
3037 && rhsoffset == UNKNOWN_OFFSET)
3039 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3042 struct constraint_expr c2;
3044 c2.type = ADDRESSOF;
3046 if (c2.var != c.var)
3047 VEC_safe_push (ce_s, heap, *results, &c2);
3052 else if (c.type == ADDRESSOF)
3055 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3057 /* Search the sub-field which overlaps with the
3058 pointed-to offset. If the result is outside of the variable
3059 we have to provide a conservative result, as the variable is
3060 still reachable from the resulting pointer (even though it
3061 technically cannot point to anything). The last and first
3062 sub-fields are such conservative results.
3063 ??? If we always had a sub-field for &object + 1 then
3064 we could represent this in a more precise way. */
3066 && curr->offset < offset)
3068 temp = first_or_preceding_vi_for_offset (curr, offset);
3070 /* If the found variable is not exactly at the pointed to
3071 result, we have to include the next variable in the
3072 solution as well. Otherwise two increments by offset / 2
3073 do not result in the same or a conservative superset
3075 if (temp->offset != offset
3076 && temp->next != NULL)
3078 struct constraint_expr c2;
3079 c2.var = temp->next->id;
3080 c2.type = ADDRESSOF;
3082 VEC_safe_push (ce_s, heap, *results, &c2);
3088 c.offset = rhsoffset;
3090 VEC_replace (ce_s, *results, j, &c);
3095 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3096 If address_p is true the result will be taken its address of. */
3099 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3103 HOST_WIDE_INT bitsize = -1;
3104 HOST_WIDE_INT bitmaxsize = -1;
3105 HOST_WIDE_INT bitpos;
3107 struct constraint_expr *result;
3109 /* Some people like to do cute things like take the address of
3112 while (handled_component_p (forzero)
3113 || INDIRECT_REF_P (forzero))
3114 forzero = TREE_OPERAND (forzero, 0);
3116 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3118 struct constraint_expr temp;
3121 temp.var = integer_id;
3123 VEC_safe_push (ce_s, heap, *results, &temp);
3127 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3129 /* Pretend to take the address of the base, we'll take care of
3130 adding the required subset of sub-fields below. */
3131 get_constraint_for_1 (t, results, true);
3132 gcc_assert (VEC_length (ce_s, *results) == 1);
3133 result = VEC_last (ce_s, *results);
3135 if (result->type == SCALAR
3136 && get_varinfo (result->var)->is_full_var)
3137 /* For single-field vars do not bother about the offset. */
3139 else if (result->type == SCALAR)
3141 /* In languages like C, you can access one past the end of an
3142 array. You aren't allowed to dereference it, so we can
3143 ignore this constraint. When we handle pointer subtraction,
3144 we may have to do something cute here. */
3146 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3149 /* It's also not true that the constraint will actually start at the
3150 right offset, it may start in some padding. We only care about
3151 setting the constraint to the first actual field it touches, so
3153 struct constraint_expr cexpr = *result;
3155 VEC_pop (ce_s, *results);
3157 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3159 if (ranges_overlap_p (curr->offset, curr->size,
3160 bitpos, bitmaxsize))
3162 cexpr.var = curr->id;
3163 VEC_safe_push (ce_s, heap, *results, &cexpr);
3168 /* If we are going to take the address of this field then
3169 to be able to compute reachability correctly add at least
3170 the last field of the variable. */
3172 && VEC_length (ce_s, *results) == 0)
3174 curr = get_varinfo (cexpr.var);
3175 while (curr->next != NULL)
3177 cexpr.var = curr->id;
3178 VEC_safe_push (ce_s, heap, *results, &cexpr);
3181 /* Assert that we found *some* field there. The user couldn't be
3182 accessing *only* padding. */
3183 /* Still the user could access one past the end of an array
3184 embedded in a struct resulting in accessing *only* padding. */
3185 gcc_assert (VEC_length (ce_s, *results) >= 1
3186 || ref_contains_array_ref (orig_t));
3188 else if (bitmaxsize == 0)
3190 if (dump_file && (dump_flags & TDF_DETAILS))
3191 fprintf (dump_file, "Access to zero-sized part of variable,"
3195 if (dump_file && (dump_flags & TDF_DETAILS))
3196 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3198 else if (result->type == DEREF)
3200 /* If we do not know exactly where the access goes say so. Note
3201 that only for non-structure accesses we know that we access
3202 at most one subfiled of any variable. */
3204 || bitsize != bitmaxsize
3205 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3206 result->offset = UNKNOWN_OFFSET;
3208 result->offset = bitpos;
3210 else if (result->type == ADDRESSOF)
3212 /* We can end up here for component references on a
3213 VIEW_CONVERT_EXPR <>(&foobar). */
3214 result->type = SCALAR;
3215 result->var = anything_id;
3223 /* Dereference the constraint expression CONS, and return the result.
3224 DEREF (ADDRESSOF) = SCALAR
3225 DEREF (SCALAR) = DEREF
3226 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3227 This is needed so that we can handle dereferencing DEREF constraints. */
3230 do_deref (VEC (ce_s, heap) **constraints)
3232 struct constraint_expr *c;
3235 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3237 if (c->type == SCALAR)
3239 else if (c->type == ADDRESSOF)
3241 else if (c->type == DEREF)
3243 struct constraint_expr tmplhs;
3244 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3245 process_constraint (new_constraint (tmplhs, *c));
3246 c->var = tmplhs.var;
3253 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3255 /* Given a tree T, return the constraint expression for taking the
3259 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3261 struct constraint_expr *c;
3264 get_constraint_for_1 (t, results, true);
3266 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3268 if (c->type == DEREF)
3271 c->type = ADDRESSOF;
3275 /* Given a tree T, return the constraint expression for it. */
3278 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3280 struct constraint_expr temp;
3282 /* x = integer is all glommed to a single variable, which doesn't
3283 point to anything by itself. That is, of course, unless it is an
3284 integer constant being treated as a pointer, in which case, we
3285 will return that this is really the addressof anything. This
3286 happens below, since it will fall into the default case. The only
3287 case we know something about an integer treated like a pointer is
3288 when it is the NULL pointer, and then we just say it points to
3291 Do not do that if -fno-delete-null-pointer-checks though, because
3292 in that case *NULL does not fail, so it _should_ alias *anything.
3293 It is not worth adding a new option or renaming the existing one,
3294 since this case is relatively obscure. */
3295 if ((TREE_CODE (t) == INTEGER_CST
3296 && integer_zerop (t))
3297 /* The only valid CONSTRUCTORs in gimple with pointer typed
3298 elements are zero-initializer. But in IPA mode we also
3299 process global initializers, so verify at least. */
3300 || (TREE_CODE (t) == CONSTRUCTOR
3301 && CONSTRUCTOR_NELTS (t) == 0))
3303 if (flag_delete_null_pointer_checks)
3304 temp.var = nothing_id;
3306 temp.var = anything_id;
3307 temp.type = ADDRESSOF;
3309 VEC_safe_push (ce_s, heap, *results, &temp);
3313 /* String constants are read-only. */
3314 if (TREE_CODE (t) == STRING_CST)
3316 temp.var = readonly_id;
3319 VEC_safe_push (ce_s, heap, *results, &temp);
3323 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3325 case tcc_expression:
3327 switch (TREE_CODE (t))
3330 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3338 switch (TREE_CODE (t))
3342 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3347 case ARRAY_RANGE_REF:
3349 get_constraint_for_component_ref (t, results, address_p);
3351 case VIEW_CONVERT_EXPR:
3352 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3354 /* We are missing handling for TARGET_MEM_REF here. */
3359 case tcc_exceptional:
3361 switch (TREE_CODE (t))
3365 get_constraint_for_ssa_var (t, results, address_p);
3372 VEC (ce_s, heap) *tmp = NULL;
3373 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3375 struct constraint_expr *rhsp;
3377 get_constraint_for_1 (val, &tmp, address_p);
3378 for (j = 0; VEC_iterate (ce_s, tmp, j, rhsp); ++j)
3379 VEC_safe_push (ce_s, heap, *results, rhsp);
3380 VEC_truncate (ce_s, tmp, 0);
3382 VEC_free (ce_s, heap, tmp);
3383 /* We do not know whether the constructor was complete,
3384 so technically we have to add &NOTHING or &ANYTHING
3385 like we do for an empty constructor as well. */
3392 case tcc_declaration:
3394 get_constraint_for_ssa_var (t, results, address_p);
3400 /* The default fallback is a constraint from anything. */
3401 temp.type = ADDRESSOF;
3402 temp.var = anything_id;
3404 VEC_safe_push (ce_s, heap, *results, &temp);
3407 /* Given a gimple tree T, return the constraint expression vector for it. */
3410 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3412 gcc_assert (VEC_length (ce_s, *results) == 0);
3414 get_constraint_for_1 (t, results, false);
3418 /* Efficiently generates constraints from all entries in *RHSC to all
3419 entries in *LHSC. */
3422 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3424 struct constraint_expr *lhsp, *rhsp;
3427 if (VEC_length (ce_s, lhsc) <= 1
3428 || VEC_length (ce_s, rhsc) <= 1)
3430 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3431 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3432 process_constraint (new_constraint (*lhsp, *rhsp));
3436 struct constraint_expr tmp;
3437 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3438 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3439 process_constraint (new_constraint (tmp, *rhsp));
3440 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3441 process_constraint (new_constraint (*lhsp, tmp));
3445 /* Handle aggregate copies by expanding into copies of the respective
3446 fields of the structures. */
3449 do_structure_copy (tree lhsop, tree rhsop)
3451 struct constraint_expr *lhsp, *rhsp;
3452 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3455 get_constraint_for (lhsop, &lhsc);
3456 get_constraint_for (rhsop, &rhsc);
3457 lhsp = VEC_index (ce_s, lhsc, 0);
3458 rhsp = VEC_index (ce_s, rhsc, 0);
3459 if (lhsp->type == DEREF
3460 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3461 || rhsp->type == DEREF)
3463 if (lhsp->type == DEREF)
3465 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3466 lhsp->offset = UNKNOWN_OFFSET;
3468 if (rhsp->type == DEREF)
3470 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3471 rhsp->offset = UNKNOWN_OFFSET;
3473 process_all_all_constraints (lhsc, rhsc);
3475 else if (lhsp->type == SCALAR
3476 && (rhsp->type == SCALAR
3477 || rhsp->type == ADDRESSOF))
3479 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3480 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3482 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3483 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3484 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3486 varinfo_t lhsv, rhsv;
3487 rhsp = VEC_index (ce_s, rhsc, k);
3488 lhsv = get_varinfo (lhsp->var);
3489 rhsv = get_varinfo (rhsp->var);
3490 if (lhsv->may_have_pointers
3491 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3492 rhsv->offset + lhsoffset, rhsv->size))
3493 process_constraint (new_constraint (*lhsp, *rhsp));
3494 if (lhsv->offset + rhsoffset + lhsv->size
3495 > rhsv->offset + lhsoffset + rhsv->size)
3498 if (k >= VEC_length (ce_s, rhsc))
3508 VEC_free (ce_s, heap, lhsc);
3509 VEC_free (ce_s, heap, rhsc);
3512 /* Create a constraint ID = OP. */
3515 make_constraint_to (unsigned id, tree op)
3517 VEC(ce_s, heap) *rhsc = NULL;
3518 struct constraint_expr *c;
3519 struct constraint_expr includes;
3523 includes.offset = 0;
3524 includes.type = SCALAR;
3526 get_constraint_for (op, &rhsc);
3527 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3528 process_constraint (new_constraint (includes, *c));
3529 VEC_free (ce_s, heap, rhsc);
3532 /* Create a constraint ID = &FROM. */
3535 make_constraint_from (varinfo_t vi, int from)
3537 struct constraint_expr lhs, rhs;
3545 rhs.type = ADDRESSOF;
3546 process_constraint (new_constraint (lhs, rhs));
3549 /* Create a constraint ID = FROM. */
3552 make_copy_constraint (varinfo_t vi, int from)
3554 struct constraint_expr lhs, rhs;
3563 process_constraint (new_constraint (lhs, rhs));
3566 /* Make constraints necessary to make OP escape. */
3569 make_escape_constraint (tree op)
3571 make_constraint_to (escaped_id, op);
3574 /* Add constraints to that the solution of VI is transitively closed. */
3577 make_transitive_closure_constraints (varinfo_t vi)
3579 struct constraint_expr lhs, rhs;
3588 process_constraint (new_constraint (lhs, rhs));
3590 /* VAR = VAR + UNKNOWN; */
3596 rhs.offset = UNKNOWN_OFFSET;
3597 process_constraint (new_constraint (lhs, rhs));
3600 /* Create a new artificial heap variable with NAME.
3601 Return the created variable. */
3604 make_heapvar_for (varinfo_t lhs, const char *name)
3607 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3609 if (heapvar == NULL_TREE)
3612 heapvar = create_tmp_var_raw (ptr_type_node, name);
3613 DECL_EXTERNAL (heapvar) = 1;
3615 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3617 ann = get_var_ann (heapvar);
3618 ann->is_heapvar = 1;
3621 /* For global vars we need to add a heapvar to the list of referenced
3622 vars of a different function than it was created for originally. */
3623 if (cfun && gimple_referenced_vars (cfun))
3624 add_referenced_var (heapvar);
3626 vi = new_var_info (heapvar, name);
3627 vi->is_artificial_var = true;
3628 vi->is_heap_var = true;
3629 vi->is_unknown_size_var = true;
3633 vi->is_full_var = true;
3634 insert_vi_for_tree (heapvar, vi);
3639 /* Create a new artificial heap variable with NAME and make a
3640 constraint from it to LHS. Return the created variable. */
3643 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3645 varinfo_t vi = make_heapvar_for (lhs, name);
3646 make_constraint_from (lhs, vi->id);
3651 /* Create a new artificial heap variable with NAME and make a
3652 constraint from it to LHS. Set flags according to a tag used
3653 for tracking restrict pointers. */
3656 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3659 vi = make_constraint_from_heapvar (lhs, name);
3660 vi->is_restrict_var = 1;
3661 vi->is_global_var = 0;
3662 vi->is_special_var = 1;
3663 vi->may_have_pointers = 0;
3666 /* In IPA mode there are varinfos for different aspects of reach
3667 function designator. One for the points-to set of the return
3668 value, one for the variables that are clobbered by the function,
3669 one for its uses and one for each parameter (including a single
3670 glob for remaining variadic arguments). */
3672 enum { fi_clobbers = 1, fi_uses = 2,
3673 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3675 /* Get a constraint for the requested part of a function designator FI
3676 when operating in IPA mode. */
3678 static struct constraint_expr
3679 get_function_part_constraint (varinfo_t fi, unsigned part)
3681 struct constraint_expr c;
3683 gcc_assert (in_ipa_mode);
3685 if (fi->id == anything_id)
3687 /* ??? We probably should have a ANYFN special variable. */
3688 c.var = anything_id;
3692 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3694 varinfo_t ai = first_vi_for_offset (fi, part);
3698 c.var = anything_id;
3712 /* For non-IPA mode, generate constraints necessary for a call on the
3716 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3718 struct constraint_expr rhsc;
3720 bool returns_uses = false;
3722 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3724 tree arg = gimple_call_arg (stmt, i);
3725 int flags = gimple_call_arg_flags (stmt, i);
3727 /* If the argument is not used or it does not contain pointers
3728 we can ignore it. */
3729 if ((flags & EAF_UNUSED)
3730 || !could_have_pointers (arg))
3733 /* As we compute ESCAPED context-insensitive we do not gain
3734 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3735 set. The argument would still get clobbered through the
3737 ??? We might get away with less (and more precise) constraints
3738 if using a temporary for transitively closing things. */
3739 if ((flags & EAF_NOCLOBBER)
3740 && (flags & EAF_NOESCAPE))
3742 varinfo_t uses = get_call_use_vi (stmt);
3743 if (!(flags & EAF_DIRECT))
3744 make_transitive_closure_constraints (uses);
3745 make_constraint_to (uses->id, arg);
3746 returns_uses = true;
3748 else if (flags & EAF_NOESCAPE)
3750 varinfo_t uses = get_call_use_vi (stmt);
3751 varinfo_t clobbers = get_call_clobber_vi (stmt);
3752 if (!(flags & EAF_DIRECT))
3754 make_transitive_closure_constraints (uses);
3755 make_transitive_closure_constraints (clobbers);
3757 make_constraint_to (uses->id, arg);
3758 make_constraint_to (clobbers->id, arg);
3759 returns_uses = true;
3762 make_escape_constraint (arg);
3765 /* If we added to the calls uses solution make sure we account for
3766 pointers to it to be returned. */
3769 rhsc.var = get_call_use_vi (stmt)->id;
3772 VEC_safe_push (ce_s, heap, *results, &rhsc);
3775 /* The static chain escapes as well. */
3776 if (gimple_call_chain (stmt))
3777 make_escape_constraint (gimple_call_chain (stmt));
3779 /* And if we applied NRV the address of the return slot escapes as well. */
3780 if (gimple_call_return_slot_opt_p (stmt)
3781 && gimple_call_lhs (stmt) != NULL_TREE
3782 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3784 VEC(ce_s, heap) *tmpc = NULL;
3785 struct constraint_expr lhsc, *c;
3786 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3787 lhsc.var = escaped_id;
3790 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3791 process_constraint (new_constraint (lhsc, *c));
3792 VEC_free(ce_s, heap, tmpc);
3795 /* Regular functions return nonlocal memory. */
3796 rhsc.var = nonlocal_id;
3799 VEC_safe_push (ce_s, heap, *results, &rhsc);
3802 /* For non-IPA mode, generate constraints necessary for a call
3803 that returns a pointer and assigns it to LHS. This simply makes
3804 the LHS point to global and escaped variables. */
3807 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3810 VEC(ce_s, heap) *lhsc = NULL;
3812 get_constraint_for (lhs, &lhsc);
3813 /* If the store is to a global decl make sure to
3814 add proper escape constraints. */
3815 lhs = get_base_address (lhs);
3818 && is_global_var (lhs))
3820 struct constraint_expr tmpc;
3821 tmpc.var = escaped_id;
3824 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3827 /* If the call returns an argument unmodified override the rhs
3829 flags = gimple_call_return_flags (stmt);
3830 if (flags & ERF_RETURNS_ARG
3831 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3835 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3836 get_constraint_for (arg, &rhsc);
3837 process_all_all_constraints (lhsc, rhsc);
3838 VEC_free (ce_s, heap, rhsc);
3840 else if (flags & ERF_NOALIAS)
3843 struct constraint_expr tmpc;
3845 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3846 /* We delay marking allocated storage global until we know if
3848 DECL_EXTERNAL (vi->decl) = 0;
3849 vi->is_global_var = 0;
3850 /* If this is not a real malloc call assume the memory was
3851 initialized and thus may point to global memory. All
3852 builtin functions with the malloc attribute behave in a sane way. */
3854 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3855 make_constraint_from (vi, nonlocal_id);
3858 tmpc.type = ADDRESSOF;
3859 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3862 process_all_all_constraints (lhsc, rhsc);
3864 VEC_free (ce_s, heap, lhsc);
3867 /* For non-IPA mode, generate constraints necessary for a call of a
3868 const function that returns a pointer in the statement STMT. */
3871 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3873 struct constraint_expr rhsc;
3876 /* Treat nested const functions the same as pure functions as far
3877 as the static chain is concerned. */
3878 if (gimple_call_chain (stmt))
3880 varinfo_t uses = get_call_use_vi (stmt);
3881 make_transitive_closure_constraints (uses);
3882 make_constraint_to (uses->id, gimple_call_chain (stmt));
3883 rhsc.var = uses->id;
3886 VEC_safe_push (ce_s, heap, *results, &rhsc);
3889 /* May return arguments. */
3890 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3892 tree arg = gimple_call_arg (stmt, k);
3894 if (could_have_pointers (arg))
3896 VEC(ce_s, heap) *argc = NULL;
3898 struct constraint_expr *argp;
3899 get_constraint_for (arg, &argc);
3900 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3901 VEC_safe_push (ce_s, heap, *results, argp);
3902 VEC_free(ce_s, heap, argc);
3906 /* May return addresses of globals. */
3907 rhsc.var = nonlocal_id;
3909 rhsc.type = ADDRESSOF;
3910 VEC_safe_push (ce_s, heap, *results, &rhsc);
3913 /* For non-IPA mode, generate constraints necessary for a call to a
3914 pure function in statement STMT. */
3917 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3919 struct constraint_expr rhsc;
3921 varinfo_t uses = NULL;
3923 /* Memory reached from pointer arguments is call-used. */
3924 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3926 tree arg = gimple_call_arg (stmt, i);
3928 if (could_have_pointers (arg))
3932 uses = get_call_use_vi (stmt);
3933 make_transitive_closure_constraints (uses);
3935 make_constraint_to (uses->id, arg);
3939 /* The static chain is used as well. */
3940 if (gimple_call_chain (stmt))
3944 uses = get_call_use_vi (stmt);
3945 make_transitive_closure_constraints (uses);
3947 make_constraint_to (uses->id, gimple_call_chain (stmt));
3950 /* Pure functions may return call-used and nonlocal memory. */
3953 rhsc.var = uses->id;
3956 VEC_safe_push (ce_s, heap, *results, &rhsc);
3958 rhsc.var = nonlocal_id;
3961 VEC_safe_push (ce_s, heap, *results, &rhsc);
3965 /* Return the varinfo for the callee of CALL. */
3968 get_fi_for_callee (gimple call)
3972 /* If we can directly resolve the function being called, do so.
3973 Otherwise, it must be some sort of indirect expression that
3974 we should still be able to handle. */
3975 decl = gimple_call_fndecl (call);
3977 return get_vi_for_tree (decl);
3979 decl = gimple_call_fn (call);
3980 /* The function can be either an SSA name pointer or,
3981 worse, an OBJ_TYPE_REF. In this case we have no
3982 clue and should be getting ANYFN (well, ANYTHING for now). */
3983 if (TREE_CODE (decl) == SSA_NAME)
3985 if (TREE_CODE (decl) == SSA_NAME
3986 && TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3987 && SSA_NAME_IS_DEFAULT_DEF (decl))
3988 decl = SSA_NAME_VAR (decl);
3989 return get_vi_for_tree (decl);
3991 else if (TREE_CODE (decl) == INTEGER_CST
3992 || TREE_CODE (decl) == OBJ_TYPE_REF)
3993 return get_varinfo (anything_id);
3998 /* Walk statement T setting up aliasing constraints according to the
3999 references found in T. This function is the main part of the
4000 constraint builder. AI points to auxiliary alias information used
4001 when building alias sets and computing alias grouping heuristics. */
4004 find_func_aliases (gimple origt)
4007 VEC(ce_s, heap) *lhsc = NULL;
4008 VEC(ce_s, heap) *rhsc = NULL;
4009 struct constraint_expr *c;
4012 /* Now build constraints expressions. */
4013 if (gimple_code (t) == GIMPLE_PHI)
4015 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4017 /* Only care about pointers and structures containing
4019 if (could_have_pointers (gimple_phi_result (t)))
4024 /* For a phi node, assign all the arguments to
4026 get_constraint_for (gimple_phi_result (t), &lhsc);
4027 for (i = 0; i < gimple_phi_num_args (t); i++)
4029 tree strippedrhs = PHI_ARG_DEF (t, i);
4031 STRIP_NOPS (strippedrhs);
4032 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
4034 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
4036 struct constraint_expr *c2;
4037 while (VEC_length (ce_s, rhsc) > 0)
4039 c2 = VEC_last (ce_s, rhsc);
4040 process_constraint (new_constraint (*c, *c2));
4041 VEC_pop (ce_s, rhsc);
4047 /* In IPA mode, we need to generate constraints to pass call
4048 arguments through their calls. There are two cases,
4049 either a GIMPLE_CALL returning a value, or just a plain
4050 GIMPLE_CALL when we are not.
4052 In non-ipa mode, we need to generate constraints for each
4053 pointer passed by address. */
4054 else if (is_gimple_call (t))
4056 tree fndecl = gimple_call_fndecl (t);
4057 if (fndecl != NULL_TREE
4058 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4059 /* ??? All builtins that are handled here need to be handled
4060 in the alias-oracle query functions explicitly! */
4061 switch (DECL_FUNCTION_CODE (fndecl))
4063 /* All the following functions return a pointer to the same object
4064 as their first argument points to. The functions do not add
4065 to the ESCAPED solution. The functions make the first argument
4066 pointed to memory point to what the second argument pointed to
4067 memory points to. */
4068 case BUILT_IN_STRCPY:
4069 case BUILT_IN_STRNCPY:
4070 case BUILT_IN_BCOPY:
4071 case BUILT_IN_MEMCPY:
4072 case BUILT_IN_MEMMOVE:
4073 case BUILT_IN_MEMPCPY:
4074 case BUILT_IN_STPCPY:
4075 case BUILT_IN_STPNCPY:
4076 case BUILT_IN_STRCAT:
4077 case BUILT_IN_STRNCAT:
4079 tree res = gimple_call_lhs (t);
4080 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4081 == BUILT_IN_BCOPY ? 1 : 0));
4082 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4083 == BUILT_IN_BCOPY ? 0 : 1));
4084 if (res != NULL_TREE)
4086 get_constraint_for (res, &lhsc);
4087 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4088 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4089 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4090 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4092 get_constraint_for (dest, &rhsc);
4093 process_all_all_constraints (lhsc, rhsc);
4094 VEC_free (ce_s, heap, lhsc);
4095 VEC_free (ce_s, heap, rhsc);
4097 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4098 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4101 process_all_all_constraints (lhsc, rhsc);
4102 VEC_free (ce_s, heap, lhsc);
4103 VEC_free (ce_s, heap, rhsc);
4106 case BUILT_IN_MEMSET:
4108 tree res = gimple_call_lhs (t);
4109 tree dest = gimple_call_arg (t, 0);
4112 struct constraint_expr ac;
4113 if (res != NULL_TREE)
4115 get_constraint_for (res, &lhsc);
4116 get_constraint_for (dest, &rhsc);
4117 process_all_all_constraints (lhsc, rhsc);
4118 VEC_free (ce_s, heap, lhsc);
4119 VEC_free (ce_s, heap, rhsc);
4121 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4123 if (flag_delete_null_pointer_checks
4124 && integer_zerop (gimple_call_arg (t, 1)))
4126 ac.type = ADDRESSOF;
4127 ac.var = nothing_id;
4132 ac.var = integer_id;
4135 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4136 process_constraint (new_constraint (*lhsp, ac));
4137 VEC_free (ce_s, heap, lhsc);
4140 /* All the following functions do not return pointers, do not
4141 modify the points-to sets of memory reachable from their
4142 arguments and do not add to the ESCAPED solution. */
4143 case BUILT_IN_SINCOS:
4144 case BUILT_IN_SINCOSF:
4145 case BUILT_IN_SINCOSL:
4146 case BUILT_IN_FREXP:
4147 case BUILT_IN_FREXPF:
4148 case BUILT_IN_FREXPL:
4149 case BUILT_IN_GAMMA_R:
4150 case BUILT_IN_GAMMAF_R:
4151 case BUILT_IN_GAMMAL_R:
4152 case BUILT_IN_LGAMMA_R:
4153 case BUILT_IN_LGAMMAF_R:
4154 case BUILT_IN_LGAMMAL_R:
4156 case BUILT_IN_MODFF:
4157 case BUILT_IN_MODFL:
4158 case BUILT_IN_REMQUO:
4159 case BUILT_IN_REMQUOF:
4160 case BUILT_IN_REMQUOL:
4163 /* Trampolines are special - they set up passing the static
4165 case BUILT_IN_INIT_TRAMPOLINE:
4167 tree tramp = gimple_call_arg (t, 0);
4168 tree nfunc = gimple_call_arg (t, 1);
4169 tree frame = gimple_call_arg (t, 2);
4171 struct constraint_expr lhs, *rhsp;
4174 varinfo_t nfi = NULL;
4175 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4176 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4179 lhs = get_function_part_constraint (nfi, fi_static_chain);
4180 get_constraint_for (frame, &rhsc);
4181 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
4182 process_constraint (new_constraint (lhs, *rhsp));
4183 VEC_free (ce_s, heap, rhsc);
4185 /* Make the frame point to the function for
4186 the trampoline adjustment call. */
4187 get_constraint_for (tramp, &lhsc);
4189 get_constraint_for (nfunc, &rhsc);
4190 process_all_all_constraints (lhsc, rhsc);
4191 VEC_free (ce_s, heap, rhsc);
4192 VEC_free (ce_s, heap, lhsc);
4197 /* Else fallthru to generic handling which will let
4198 the frame escape. */
4201 case BUILT_IN_ADJUST_TRAMPOLINE:
4203 tree tramp = gimple_call_arg (t, 0);
4204 tree res = gimple_call_lhs (t);
4205 if (in_ipa_mode && res)
4207 get_constraint_for (res, &lhsc);
4208 get_constraint_for (tramp, &rhsc);
4210 process_all_all_constraints (lhsc, rhsc);
4211 VEC_free (ce_s, heap, rhsc);
4212 VEC_free (ce_s, heap, lhsc);
4216 /* Variadic argument handling needs to be handled in IPA
4218 case BUILT_IN_VA_START:
4222 tree valist = gimple_call_arg (t, 0);
4223 struct constraint_expr rhs, *lhsp;
4225 /* The va_list gets access to pointers in variadic
4227 fi = lookup_vi_for_tree (cfun->decl);
4228 gcc_assert (fi != NULL);
4229 get_constraint_for (valist, &lhsc);
4231 rhs = get_function_part_constraint (fi, ~0);
4232 rhs.type = ADDRESSOF;
4233 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4234 process_constraint (new_constraint (*lhsp, rhs));
4235 VEC_free (ce_s, heap, lhsc);
4236 /* va_list is clobbered. */
4237 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4242 /* va_end doesn't have any effect that matters. */
4243 case BUILT_IN_VA_END:
4245 /* printf-style functions may have hooks to set pointers to
4246 point to somewhere into the generated string. Leave them
4247 for a later excercise... */
4249 /* Fallthru to general call handling. */;
4253 && (!(fi = lookup_vi_for_tree (fndecl))
4254 || !fi->is_fn_info)))
4256 VEC(ce_s, heap) *rhsc = NULL;
4257 int flags = gimple_call_flags (t);
4259 /* Const functions can return their arguments and addresses
4260 of global memory but not of escaped memory. */
4261 if (flags & (ECF_CONST|ECF_NOVOPS))
4263 if (gimple_call_lhs (t)
4264 && could_have_pointers (gimple_call_lhs (t)))
4265 handle_const_call (t, &rhsc);
4267 /* Pure functions can return addresses in and of memory
4268 reachable from their arguments, but they are not an escape
4269 point for reachable memory of their arguments. */
4270 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4271 handle_pure_call (t, &rhsc);
4273 handle_rhs_call (t, &rhsc);
4274 if (gimple_call_lhs (t)
4275 && could_have_pointers (gimple_call_lhs (t)))
4276 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4277 VEC_free (ce_s, heap, rhsc);
4284 fi = get_fi_for_callee (t);
4286 /* Assign all the passed arguments to the appropriate incoming
4287 parameters of the function. */
4288 for (j = 0; j < gimple_call_num_args (t); j++)
4290 struct constraint_expr lhs ;
4291 struct constraint_expr *rhsp;
4292 tree arg = gimple_call_arg (t, j);
4294 if (!could_have_pointers (arg))
4297 get_constraint_for (arg, &rhsc);
4298 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4299 while (VEC_length (ce_s, rhsc) != 0)
4301 rhsp = VEC_last (ce_s, rhsc);
4302 process_constraint (new_constraint (lhs, *rhsp));
4303 VEC_pop (ce_s, rhsc);
4307 /* If we are returning a value, assign it to the result. */
4308 lhsop = gimple_call_lhs (t);
4310 && type_could_have_pointers (TREE_TYPE (lhsop)))
4312 struct constraint_expr rhs;
4313 struct constraint_expr *lhsp;
4315 get_constraint_for (lhsop, &lhsc);
4316 rhs = get_function_part_constraint (fi, fi_result);
4318 && DECL_RESULT (fndecl)
4319 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4321 VEC(ce_s, heap) *tem = NULL;
4322 VEC_safe_push (ce_s, heap, tem, &rhs);
4324 rhs = *VEC_index (ce_s, tem, 0);
4325 VEC_free(ce_s, heap, tem);
4327 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4328 process_constraint (new_constraint (*lhsp, rhs));
4331 /* If we pass the result decl by reference, honor that. */
4334 && DECL_RESULT (fndecl)
4335 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4337 struct constraint_expr lhs;
4338 struct constraint_expr *rhsp;
4340 get_constraint_for_address_of (lhsop, &rhsc);
4341 lhs = get_function_part_constraint (fi, fi_result);
4342 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4343 process_constraint (new_constraint (lhs, *rhsp));
4344 VEC_free (ce_s, heap, rhsc);
4347 /* If we use a static chain, pass it along. */
4348 if (gimple_call_chain (t))
4350 struct constraint_expr lhs;
4351 struct constraint_expr *rhsp;
4353 get_constraint_for (gimple_call_chain (t), &rhsc);
4354 lhs = get_function_part_constraint (fi, fi_static_chain);
4355 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4356 process_constraint (new_constraint (lhs, *rhsp));
4360 /* Otherwise, just a regular assignment statement. Only care about
4361 operations with pointer result, others are dealt with as escape
4362 points if they have pointer operands. */
4363 else if (is_gimple_assign (t)
4364 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4366 /* Otherwise, just a regular assignment statement. */
4367 tree lhsop = gimple_assign_lhs (t);
4368 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4370 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4371 do_structure_copy (lhsop, rhsop);
4374 struct constraint_expr temp;
4375 get_constraint_for (lhsop, &lhsc);
4377 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4378 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4379 gimple_assign_rhs2 (t), &rhsc);
4380 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4381 && !(POINTER_TYPE_P (gimple_expr_type (t))
4382 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4383 || gimple_assign_single_p (t))
4384 get_constraint_for (rhsop, &rhsc);
4387 temp.type = ADDRESSOF;
4388 temp.var = anything_id;
4390 VEC_safe_push (ce_s, heap, rhsc, &temp);
4392 process_all_all_constraints (lhsc, rhsc);
4394 /* If there is a store to a global variable the rhs escapes. */
4395 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4397 && is_global_var (lhsop)
4399 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4400 make_escape_constraint (rhsop);
4401 /* If this is a conversion of a non-restrict pointer to a
4402 restrict pointer track it with a new heapvar. */
4403 else if (gimple_assign_cast_p (t)
4404 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4405 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4406 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4407 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4408 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4411 /* For conversions of pointers to non-pointers the pointer escapes. */
4412 else if (gimple_assign_cast_p (t)
4413 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4414 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4416 make_escape_constraint (gimple_assign_rhs1 (t));
4418 /* Handle escapes through return. */
4419 else if (gimple_code (t) == GIMPLE_RETURN
4420 && gimple_return_retval (t) != NULL_TREE
4421 && could_have_pointers (gimple_return_retval (t)))
4425 || !(fi = get_vi_for_tree (cfun->decl)))
4426 make_escape_constraint (gimple_return_retval (t));
4427 else if (in_ipa_mode
4430 struct constraint_expr lhs ;
4431 struct constraint_expr *rhsp;
4434 lhs = get_function_part_constraint (fi, fi_result);
4435 get_constraint_for (gimple_return_retval (t), &rhsc);
4436 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4437 process_constraint (new_constraint (lhs, *rhsp));
4440 /* Handle asms conservatively by adding escape constraints to everything. */
4441 else if (gimple_code (t) == GIMPLE_ASM)
4443 unsigned i, noutputs;
4444 const char **oconstraints;
4445 const char *constraint;
4446 bool allows_mem, allows_reg, is_inout;
4448 noutputs = gimple_asm_noutputs (t);
4449 oconstraints = XALLOCAVEC (const char *, noutputs);
4451 for (i = 0; i < noutputs; ++i)
4453 tree link = gimple_asm_output_op (t, i);
4454 tree op = TREE_VALUE (link);
4456 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4457 oconstraints[i] = constraint;
4458 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4459 &allows_reg, &is_inout);
4461 /* A memory constraint makes the address of the operand escape. */
4462 if (!allows_reg && allows_mem)
4463 make_escape_constraint (build_fold_addr_expr (op));
4465 /* The asm may read global memory, so outputs may point to
4466 any global memory. */
4467 if (op && could_have_pointers (op))
4469 VEC(ce_s, heap) *lhsc = NULL;
4470 struct constraint_expr rhsc, *lhsp;
4472 get_constraint_for (op, &lhsc);
4473 rhsc.var = nonlocal_id;
4476 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4477 process_constraint (new_constraint (*lhsp, rhsc));
4478 VEC_free (ce_s, heap, lhsc);
4481 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4483 tree link = gimple_asm_input_op (t, i);
4484 tree op = TREE_VALUE (link);
4486 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4488 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4489 &allows_mem, &allows_reg);
4491 /* A memory constraint makes the address of the operand escape. */
4492 if (!allows_reg && allows_mem)
4493 make_escape_constraint (build_fold_addr_expr (op));
4494 /* Strictly we'd only need the constraint to ESCAPED if
4495 the asm clobbers memory, otherwise using something
4496 along the lines of per-call clobbers/uses would be enough. */
4497 else if (op && could_have_pointers (op))
4498 make_escape_constraint (op);
4502 VEC_free (ce_s, heap, rhsc);
4503 VEC_free (ce_s, heap, lhsc);
4507 /* Create a constraint adding to the clobber set of FI the memory
4508 pointed to by PTR. */
4511 process_ipa_clobber (varinfo_t fi, tree ptr)
4513 VEC(ce_s, heap) *ptrc = NULL;
4514 struct constraint_expr *c, lhs;
4516 get_constraint_for (ptr, &ptrc);
4517 lhs = get_function_part_constraint (fi, fi_clobbers);
4518 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4519 process_constraint (new_constraint (lhs, *c));
4520 VEC_free (ce_s, heap, ptrc);
4523 /* Walk statement T setting up clobber and use constraints according to the
4524 references found in T. This function is a main part of the
4525 IPA constraint builder. */
4528 find_func_clobbers (gimple origt)
4531 VEC(ce_s, heap) *lhsc = NULL;
4532 VEC(ce_s, heap) *rhsc = NULL;
4535 /* Add constraints for clobbered/used in IPA mode.
4536 We are not interested in what automatic variables are clobbered
4537 or used as we only use the information in the caller to which
4538 they do not escape. */
4539 gcc_assert (in_ipa_mode);
4541 /* If the stmt refers to memory in any way it better had a VUSE. */
4542 if (gimple_vuse (t) == NULL_TREE)
4545 /* We'd better have function information for the current function. */
4546 fi = lookup_vi_for_tree (cfun->decl);
4547 gcc_assert (fi != NULL);
4549 /* Account for stores in assignments and calls. */
4550 if (gimple_vdef (t) != NULL_TREE
4551 && gimple_has_lhs (t))
4553 tree lhs = gimple_get_lhs (t);
4555 while (handled_component_p (tem))
4556 tem = TREE_OPERAND (tem, 0);
4558 && !auto_var_in_fn_p (tem, cfun->decl))
4559 || INDIRECT_REF_P (tem))
4561 struct constraint_expr lhsc, *rhsp;
4563 lhsc = get_function_part_constraint (fi, fi_clobbers);
4564 get_constraint_for_address_of (lhs, &rhsc);
4565 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4566 process_constraint (new_constraint (lhsc, *rhsp));
4567 VEC_free (ce_s, heap, rhsc);
4571 /* Account for uses in assigments and returns. */
4572 if (gimple_assign_single_p (t)
4573 || (gimple_code (t) == GIMPLE_RETURN
4574 && gimple_return_retval (t) != NULL_TREE))
4576 tree rhs = (gimple_assign_single_p (t)
4577 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4579 while (handled_component_p (tem))
4580 tem = TREE_OPERAND (tem, 0);
4582 && !auto_var_in_fn_p (tem, cfun->decl))
4583 || INDIRECT_REF_P (tem))
4585 struct constraint_expr lhs, *rhsp;
4587 lhs = get_function_part_constraint (fi, fi_uses);
4588 get_constraint_for_address_of (rhs, &rhsc);
4589 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4590 process_constraint (new_constraint (lhs, *rhsp));
4591 VEC_free (ce_s, heap, rhsc);
4595 if (is_gimple_call (t))
4597 varinfo_t cfi = NULL;
4598 tree decl = gimple_call_fndecl (t);
4599 struct constraint_expr lhs, rhs;
4602 /* For builtins we do not have separate function info. For those
4603 we do not generate escapes for we have to generate clobbers/uses. */
4605 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4606 switch (DECL_FUNCTION_CODE (decl))
4608 /* The following functions use and clobber memory pointed to
4609 by their arguments. */
4610 case BUILT_IN_STRCPY:
4611 case BUILT_IN_STRNCPY:
4612 case BUILT_IN_BCOPY:
4613 case BUILT_IN_MEMCPY:
4614 case BUILT_IN_MEMMOVE:
4615 case BUILT_IN_MEMPCPY:
4616 case BUILT_IN_STPCPY:
4617 case BUILT_IN_STPNCPY:
4618 case BUILT_IN_STRCAT:
4619 case BUILT_IN_STRNCAT:
4621 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4622 == BUILT_IN_BCOPY ? 1 : 0));
4623 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4624 == BUILT_IN_BCOPY ? 0 : 1));
4626 struct constraint_expr *rhsp, *lhsp;
4627 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4628 lhs = get_function_part_constraint (fi, fi_clobbers);
4629 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4630 process_constraint (new_constraint (lhs, *lhsp));
4631 VEC_free (ce_s, heap, lhsc);
4632 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4633 lhs = get_function_part_constraint (fi, fi_uses);
4634 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4635 process_constraint (new_constraint (lhs, *rhsp));
4636 VEC_free (ce_s, heap, rhsc);
4639 /* The following function clobbers memory pointed to by
4641 case BUILT_IN_MEMSET:
4643 tree dest = gimple_call_arg (t, 0);
4646 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4647 lhs = get_function_part_constraint (fi, fi_clobbers);
4648 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4649 process_constraint (new_constraint (lhs, *lhsp));
4650 VEC_free (ce_s, heap, lhsc);
4653 /* The following functions clobber their second and third
4655 case BUILT_IN_SINCOS:
4656 case BUILT_IN_SINCOSF:
4657 case BUILT_IN_SINCOSL:
4659 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4660 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4663 /* The following functions clobber their second argument. */
4664 case BUILT_IN_FREXP:
4665 case BUILT_IN_FREXPF:
4666 case BUILT_IN_FREXPL:
4667 case BUILT_IN_LGAMMA_R:
4668 case BUILT_IN_LGAMMAF_R:
4669 case BUILT_IN_LGAMMAL_R:
4670 case BUILT_IN_GAMMA_R:
4671 case BUILT_IN_GAMMAF_R:
4672 case BUILT_IN_GAMMAL_R:
4674 case BUILT_IN_MODFF:
4675 case BUILT_IN_MODFL:
4677 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4680 /* The following functions clobber their third argument. */
4681 case BUILT_IN_REMQUO:
4682 case BUILT_IN_REMQUOF:
4683 case BUILT_IN_REMQUOL:
4685 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4688 /* The following functions neither read nor clobber memory. */
4691 /* Trampolines are of no interest to us. */
4692 case BUILT_IN_INIT_TRAMPOLINE:
4693 case BUILT_IN_ADJUST_TRAMPOLINE:
4695 case BUILT_IN_VA_START:
4696 case BUILT_IN_VA_END:
4698 /* printf-style functions may have hooks to set pointers to
4699 point to somewhere into the generated string. Leave them
4700 for a later excercise... */
4702 /* Fallthru to general call handling. */;
4705 /* Parameters passed by value are used. */
4706 lhs = get_function_part_constraint (fi, fi_uses);
4707 for (i = 0; i < gimple_call_num_args (t); i++)
4709 struct constraint_expr *rhsp;
4710 tree arg = gimple_call_arg (t, i);
4712 if (TREE_CODE (arg) == SSA_NAME
4713 || is_gimple_min_invariant (arg))
4716 get_constraint_for_address_of (arg, &rhsc);
4717 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4718 process_constraint (new_constraint (lhs, *rhsp));
4719 VEC_free (ce_s, heap, rhsc);
4722 /* Build constraints for propagating clobbers/uses along the
4724 cfi = get_fi_for_callee (t);
4725 if (cfi->id == anything_id)
4727 if (gimple_vdef (t))
4728 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4730 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4735 /* For callees without function info (that's external functions),
4736 ESCAPED is clobbered and used. */
4737 if (gimple_call_fndecl (t)
4738 && !cfi->is_fn_info)
4742 if (gimple_vdef (t))
4743 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4745 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4747 /* Also honor the call statement use/clobber info. */
4748 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4749 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4751 if ((vi = lookup_call_use_vi (t)) != NULL)
4752 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4757 /* Otherwise the caller clobbers and uses what the callee does.
4758 ??? This should use a new complex constraint that filters
4759 local variables of the callee. */
4760 if (gimple_vdef (t))
4762 lhs = get_function_part_constraint (fi, fi_clobbers);
4763 rhs = get_function_part_constraint (cfi, fi_clobbers);
4764 process_constraint (new_constraint (lhs, rhs));
4766 lhs = get_function_part_constraint (fi, fi_uses);
4767 rhs = get_function_part_constraint (cfi, fi_uses);
4768 process_constraint (new_constraint (lhs, rhs));
4770 else if (gimple_code (t) == GIMPLE_ASM)
4772 /* ??? Ick. We can do better. */
4773 if (gimple_vdef (t))
4774 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4776 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4780 VEC_free (ce_s, heap, rhsc);
4784 /* Find the first varinfo in the same variable as START that overlaps with
4785 OFFSET. Return NULL if we can't find one. */
4788 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4790 /* If the offset is outside of the variable, bail out. */
4791 if (offset >= start->fullsize)
4794 /* If we cannot reach offset from start, lookup the first field
4795 and start from there. */
4796 if (start->offset > offset)
4797 start = lookup_vi_for_tree (start->decl);
4801 /* We may not find a variable in the field list with the actual
4802 offset when when we have glommed a structure to a variable.
4803 In that case, however, offset should still be within the size
4805 if (offset >= start->offset
4806 && (offset - start->offset) < start->size)
4815 /* Find the first varinfo in the same variable as START that overlaps with
4816 OFFSET. If there is no such varinfo the varinfo directly preceding
4817 OFFSET is returned. */
4820 first_or_preceding_vi_for_offset (varinfo_t start,
4821 unsigned HOST_WIDE_INT offset)
4823 /* If we cannot reach offset from start, lookup the first field
4824 and start from there. */
4825 if (start->offset > offset)
4826 start = lookup_vi_for_tree (start->decl);
4828 /* We may not find a variable in the field list with the actual
4829 offset when when we have glommed a structure to a variable.
4830 In that case, however, offset should still be within the size
4832 If we got beyond the offset we look for return the field
4833 directly preceding offset which may be the last field. */
4835 && offset >= start->offset
4836 && !((offset - start->offset) < start->size))
4837 start = start->next;
4843 /* This structure is used during pushing fields onto the fieldstack
4844 to track the offset of the field, since bitpos_of_field gives it
4845 relative to its immediate containing type, and we want it relative
4846 to the ultimate containing object. */
4850 /* Offset from the base of the base containing object to this field. */
4851 HOST_WIDE_INT offset;
4853 /* Size, in bits, of the field. */
4854 unsigned HOST_WIDE_INT size;
4856 unsigned has_unknown_size : 1;
4858 unsigned may_have_pointers : 1;
4860 unsigned only_restrict_pointers : 1;
4862 typedef struct fieldoff fieldoff_s;
4864 DEF_VEC_O(fieldoff_s);
4865 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4867 /* qsort comparison function for two fieldoff's PA and PB */
4870 fieldoff_compare (const void *pa, const void *pb)
4872 const fieldoff_s *foa = (const fieldoff_s *)pa;
4873 const fieldoff_s *fob = (const fieldoff_s *)pb;
4874 unsigned HOST_WIDE_INT foasize, fobsize;
4876 if (foa->offset < fob->offset)
4878 else if (foa->offset > fob->offset)
4881 foasize = foa->size;
4882 fobsize = fob->size;
4883 if (foasize < fobsize)
4885 else if (foasize > fobsize)
4890 /* Sort a fieldstack according to the field offset and sizes. */
4892 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4894 qsort (VEC_address (fieldoff_s, fieldstack),
4895 VEC_length (fieldoff_s, fieldstack),
4896 sizeof (fieldoff_s),
4900 /* Return true if V is a tree that we can have subvars for.
4901 Normally, this is any aggregate type. Also complex
4902 types which are not gimple registers can have subvars. */
4905 var_can_have_subvars (const_tree v)
4907 /* Volatile variables should never have subvars. */
4908 if (TREE_THIS_VOLATILE (v))
4911 /* Non decls or memory tags can never have subvars. */
4915 /* Aggregates without overlapping fields can have subvars. */
4916 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4922 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4923 the fields of TYPE onto fieldstack, recording their offsets along
4926 OFFSET is used to keep track of the offset in this entire
4927 structure, rather than just the immediately containing structure.
4928 Returns false if the caller is supposed to handle the field we
4932 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4933 HOST_WIDE_INT offset, bool must_have_pointers_p)
4936 bool empty_p = true;
4938 if (TREE_CODE (type) != RECORD_TYPE)
4941 /* If the vector of fields is growing too big, bail out early.
4942 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4944 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4947 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4948 if (TREE_CODE (field) == FIELD_DECL)
4951 HOST_WIDE_INT foff = bitpos_of_field (field);
4953 if (!var_can_have_subvars (field)
4954 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4955 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4957 else if (!push_fields_onto_fieldstack
4958 (TREE_TYPE (field), fieldstack, offset + foff,
4959 must_have_pointers_p)
4960 && (DECL_SIZE (field)
4961 && !integer_zerop (DECL_SIZE (field))))
4962 /* Empty structures may have actual size, like in C++. So
4963 see if we didn't push any subfields and the size is
4964 nonzero, push the field onto the stack. */
4969 fieldoff_s *pair = NULL;
4970 bool has_unknown_size = false;
4972 if (!VEC_empty (fieldoff_s, *fieldstack))
4973 pair = VEC_last (fieldoff_s, *fieldstack);
4975 if (!DECL_SIZE (field)
4976 || !host_integerp (DECL_SIZE (field), 1))
4977 has_unknown_size = true;
4979 /* If adjacent fields do not contain pointers merge them. */
4981 && !pair->may_have_pointers
4982 && !pair->has_unknown_size
4983 && !has_unknown_size
4984 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
4985 && !must_have_pointers_p
4986 && !could_have_pointers (field))
4988 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
4992 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
4993 pair->offset = offset + foff;
4994 pair->has_unknown_size = has_unknown_size;
4995 if (!has_unknown_size)
4996 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
4999 pair->may_have_pointers
5000 = must_have_pointers_p || could_have_pointers (field);
5001 pair->only_restrict_pointers
5002 = (!has_unknown_size
5003 && POINTER_TYPE_P (TREE_TYPE (field))
5004 && TYPE_RESTRICT (TREE_TYPE (field)));
5014 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5015 if it is a varargs function. */
5018 count_num_arguments (tree decl, bool *is_varargs)
5020 unsigned int num = 0;
5023 /* Capture named arguments for K&R functions. They do not
5024 have a prototype and thus no TYPE_ARG_TYPES. */
5025 for (t = DECL_ARGUMENTS (decl); t; t = TREE_CHAIN (t))
5028 /* Check if the function has variadic arguments. */
5029 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5030 if (TREE_VALUE (t) == void_type_node)
5038 /* Creation function node for DECL, using NAME, and return the index
5039 of the variable we've created for the function. */
5042 create_function_info_for (tree decl, const char *name)
5044 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5045 varinfo_t vi, prev_vi;
5048 bool is_varargs = false;
5049 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5051 /* Create the variable info. */
5053 vi = new_var_info (decl, name);
5056 vi->fullsize = fi_parm_base + num_args;
5058 vi->may_have_pointers = false;
5061 insert_vi_for_tree (vi->decl, vi);
5065 /* Create a variable for things the function clobbers and one for
5066 things the function uses. */
5068 varinfo_t clobbervi, usevi;
5069 const char *newname;
5072 asprintf (&tempname, "%s.clobber", name);
5073 newname = ggc_strdup (tempname);
5076 clobbervi = new_var_info (NULL, newname);
5077 clobbervi->offset = fi_clobbers;
5078 clobbervi->size = 1;
5079 clobbervi->fullsize = vi->fullsize;
5080 clobbervi->is_full_var = true;
5081 clobbervi->is_global_var = false;
5082 gcc_assert (prev_vi->offset < clobbervi->offset);
5083 prev_vi->next = clobbervi;
5084 prev_vi = clobbervi;
5086 asprintf (&tempname, "%s.use", name);
5087 newname = ggc_strdup (tempname);
5090 usevi = new_var_info (NULL, newname);
5091 usevi->offset = fi_uses;
5093 usevi->fullsize = vi->fullsize;
5094 usevi->is_full_var = true;
5095 usevi->is_global_var = false;
5096 gcc_assert (prev_vi->offset < usevi->offset);
5097 prev_vi->next = usevi;
5101 /* And one for the static chain. */
5102 if (fn->static_chain_decl != NULL_TREE)
5105 const char *newname;
5108 asprintf (&tempname, "%s.chain", name);
5109 newname = ggc_strdup (tempname);
5112 chainvi = new_var_info (fn->static_chain_decl, newname);
5113 chainvi->offset = fi_static_chain;
5115 chainvi->fullsize = vi->fullsize;
5116 chainvi->is_full_var = true;
5117 chainvi->is_global_var = false;
5118 gcc_assert (prev_vi->offset < chainvi->offset);
5119 prev_vi->next = chainvi;
5121 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5124 /* Create a variable for the return var. */
5125 if (DECL_RESULT (decl) != NULL
5126 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5129 const char *newname;
5131 tree resultdecl = decl;
5133 if (DECL_RESULT (decl))
5134 resultdecl = DECL_RESULT (decl);
5136 asprintf (&tempname, "%s.result", name);
5137 newname = ggc_strdup (tempname);
5140 resultvi = new_var_info (resultdecl, newname);
5141 resultvi->offset = fi_result;
5143 resultvi->fullsize = vi->fullsize;
5144 resultvi->is_full_var = true;
5145 if (DECL_RESULT (decl))
5146 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5147 gcc_assert (prev_vi->offset < resultvi->offset);
5148 prev_vi->next = resultvi;
5150 if (DECL_RESULT (decl))
5151 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5154 /* Set up variables for each argument. */
5155 arg = DECL_ARGUMENTS (decl);
5156 for (i = 0; i < num_args; i++)
5159 const char *newname;
5161 tree argdecl = decl;
5166 asprintf (&tempname, "%s.arg%d", name, i);
5167 newname = ggc_strdup (tempname);
5170 argvi = new_var_info (argdecl, newname);
5171 argvi->offset = fi_parm_base + i;
5173 argvi->is_full_var = true;
5174 argvi->fullsize = vi->fullsize;
5176 argvi->may_have_pointers = could_have_pointers (arg);
5177 gcc_assert (prev_vi->offset < argvi->offset);
5178 prev_vi->next = argvi;
5182 insert_vi_for_tree (arg, argvi);
5183 arg = TREE_CHAIN (arg);
5187 /* Add one representative for all further args. */
5191 const char *newname;
5195 asprintf (&tempname, "%s.varargs", name);
5196 newname = ggc_strdup (tempname);
5199 /* We need sth that can be pointed to for va_start. */
5200 decl = create_tmp_var_raw (ptr_type_node, name);
5203 argvi = new_var_info (decl, newname);
5204 argvi->offset = fi_parm_base + num_args;
5206 argvi->is_full_var = true;
5207 argvi->is_heap_var = true;
5208 argvi->fullsize = vi->fullsize;
5209 gcc_assert (prev_vi->offset < argvi->offset);
5210 prev_vi->next = argvi;
5218 /* Return true if FIELDSTACK contains fields that overlap.
5219 FIELDSTACK is assumed to be sorted by offset. */
5222 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5224 fieldoff_s *fo = NULL;
5226 HOST_WIDE_INT lastoffset = -1;
5228 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5230 if (fo->offset == lastoffset)
5232 lastoffset = fo->offset;
5237 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5238 This will also create any varinfo structures necessary for fields
5242 create_variable_info_for_1 (tree decl, const char *name)
5244 varinfo_t vi, newvi;
5245 tree decl_type = TREE_TYPE (decl);
5246 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5247 VEC (fieldoff_s,heap) *fieldstack = NULL;
5252 || !host_integerp (declsize, 1))
5254 vi = new_var_info (decl, name);
5258 vi->is_unknown_size_var = true;
5259 vi->is_full_var = true;
5260 vi->may_have_pointers = could_have_pointers (decl);
5264 /* Collect field information. */
5265 if (use_field_sensitive
5266 && var_can_have_subvars (decl)
5267 /* ??? Force us to not use subfields for global initializers
5268 in IPA mode. Else we'd have to parse arbitrary initializers. */
5270 && is_global_var (decl)
5271 && DECL_INITIAL (decl)))
5273 fieldoff_s *fo = NULL;
5274 bool notokay = false;
5277 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5279 || DECL_EXTERNAL (decl)
5280 || TREE_ADDRESSABLE (decl));
5282 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5283 if (fo->has_unknown_size
5290 /* We can't sort them if we have a field with a variable sized type,
5291 which will make notokay = true. In that case, we are going to return
5292 without creating varinfos for the fields anyway, so sorting them is a
5296 sort_fieldstack (fieldstack);
5297 /* Due to some C++ FE issues, like PR 22488, we might end up
5298 what appear to be overlapping fields even though they,
5299 in reality, do not overlap. Until the C++ FE is fixed,
5300 we will simply disable field-sensitivity for these cases. */
5301 notokay = check_for_overlaps (fieldstack);
5305 VEC_free (fieldoff_s, heap, fieldstack);
5308 /* If we didn't end up collecting sub-variables create a full
5309 variable for the decl. */
5310 if (VEC_length (fieldoff_s, fieldstack) <= 1
5311 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5313 vi = new_var_info (decl, name);
5315 vi->may_have_pointers = could_have_pointers (decl);
5316 vi->fullsize = TREE_INT_CST_LOW (declsize);
5317 vi->size = vi->fullsize;
5318 vi->is_full_var = true;
5319 VEC_free (fieldoff_s, heap, fieldstack);
5323 vi = new_var_info (decl, name);
5324 vi->fullsize = TREE_INT_CST_LOW (declsize);
5325 for (i = 0, newvi = vi;
5326 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5327 ++i, newvi = newvi->next)
5329 const char *newname = "NULL";
5334 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5335 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5336 newname = ggc_strdup (tempname);
5339 newvi->name = newname;
5340 newvi->offset = fo->offset;
5341 newvi->size = fo->size;
5342 newvi->fullsize = vi->fullsize;
5343 newvi->may_have_pointers = fo->may_have_pointers;
5344 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5345 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5346 newvi->next = new_var_info (decl, name);
5349 VEC_free (fieldoff_s, heap, fieldstack);
5355 create_variable_info_for (tree decl, const char *name)
5357 varinfo_t vi = create_variable_info_for_1 (decl, name);
5358 unsigned int id = vi->id;
5360 insert_vi_for_tree (decl, vi);
5362 /* Create initial constraints for globals. */
5363 for (; vi; vi = vi->next)
5365 if (!vi->may_have_pointers
5366 || !vi->is_global_var)
5369 /* Mark global restrict qualified pointers. */
5370 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5371 && TYPE_RESTRICT (TREE_TYPE (decl)))
5372 || vi->only_restrict_pointers)
5373 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5375 /* For escaped variables initialize them from nonlocal. */
5377 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5378 make_copy_constraint (vi, nonlocal_id);
5380 /* If this is a global variable with an initializer and we are in
5381 IPA mode generate constraints for it. In non-IPA mode
5382 the initializer from nonlocal is all we need. */
5384 && DECL_INITIAL (decl))
5386 VEC (ce_s, heap) *rhsc = NULL;
5387 struct constraint_expr lhs, *rhsp;
5389 get_constraint_for (DECL_INITIAL (decl), &rhsc);
5393 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5394 process_constraint (new_constraint (lhs, *rhsp));
5395 /* If this is a variable that escapes from the unit
5396 the initializer escapes as well. */
5397 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5399 lhs.var = escaped_id;
5402 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5403 process_constraint (new_constraint (lhs, *rhsp));
5405 VEC_free (ce_s, heap, rhsc);
5412 /* Print out the points-to solution for VAR to FILE. */
5415 dump_solution_for_var (FILE *file, unsigned int var)
5417 varinfo_t vi = get_varinfo (var);
5421 /* Dump the solution for unified vars anyway, this avoids difficulties
5422 in scanning dumps in the testsuite. */
5423 fprintf (file, "%s = { ", vi->name);
5424 vi = get_varinfo (find (var));
5425 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5426 fprintf (file, "%s ", get_varinfo (i)->name);
5427 fprintf (file, "}");
5429 /* But note when the variable was unified. */
5431 fprintf (file, " same as %s", vi->name);
5433 fprintf (file, "\n");
5436 /* Print the points-to solution for VAR to stdout. */
5439 debug_solution_for_var (unsigned int var)
5441 dump_solution_for_var (stdout, var);
5444 /* Create varinfo structures for all of the variables in the
5445 function for intraprocedural mode. */
5448 intra_create_variable_infos (void)
5452 /* For each incoming pointer argument arg, create the constraint ARG
5453 = NONLOCAL or a dummy variable if it is a restrict qualified
5454 passed-by-reference argument. */
5455 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
5459 if (!could_have_pointers (t))
5462 /* For restrict qualified pointers to objects passed by
5463 reference build a real representative for the pointed-to object. */
5464 if (DECL_BY_REFERENCE (t)
5465 && POINTER_TYPE_P (TREE_TYPE (t))
5466 && TYPE_RESTRICT (TREE_TYPE (t)))
5468 struct constraint_expr lhsc, rhsc;
5470 tree heapvar = heapvar_lookup (t, 0);
5471 if (heapvar == NULL_TREE)
5474 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5476 DECL_EXTERNAL (heapvar) = 1;
5477 heapvar_insert (t, 0, heapvar);
5478 ann = get_var_ann (heapvar);
5479 ann->is_heapvar = 1;
5481 if (gimple_referenced_vars (cfun))
5482 add_referenced_var (heapvar);
5483 lhsc.var = get_vi_for_tree (t)->id;
5486 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5487 rhsc.type = ADDRESSOF;
5489 process_constraint (new_constraint (lhsc, rhsc));
5490 vi->is_restrict_var = 1;
5494 for (p = get_vi_for_tree (t); p; p = p->next)
5496 if (p->may_have_pointers)
5497 make_constraint_from (p, nonlocal_id);
5498 if (p->only_restrict_pointers)
5499 make_constraint_from_restrict (p, "PARM_RESTRICT");
5501 if (POINTER_TYPE_P (TREE_TYPE (t))
5502 && TYPE_RESTRICT (TREE_TYPE (t)))
5503 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5506 /* Add a constraint for a result decl that is passed by reference. */
5507 if (DECL_RESULT (cfun->decl)
5508 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5510 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5512 for (p = result_vi; p; p = p->next)
5513 make_constraint_from (p, nonlocal_id);
5516 /* Add a constraint for the incoming static chain parameter. */
5517 if (cfun->static_chain_decl != NULL_TREE)
5519 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5521 for (p = chain_vi; p; p = p->next)
5522 make_constraint_from (p, nonlocal_id);
5526 /* Structure used to put solution bitmaps in a hashtable so they can
5527 be shared among variables with the same points-to set. */
5529 typedef struct shared_bitmap_info
5533 } *shared_bitmap_info_t;
5534 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5536 static htab_t shared_bitmap_table;
5538 /* Hash function for a shared_bitmap_info_t */
5541 shared_bitmap_hash (const void *p)
5543 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5544 return bi->hashcode;
5547 /* Equality function for two shared_bitmap_info_t's. */
5550 shared_bitmap_eq (const void *p1, const void *p2)
5552 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5553 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5554 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5557 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5558 existing instance if there is one, NULL otherwise. */
5561 shared_bitmap_lookup (bitmap pt_vars)
5564 struct shared_bitmap_info sbi;
5566 sbi.pt_vars = pt_vars;
5567 sbi.hashcode = bitmap_hash (pt_vars);
5569 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5570 sbi.hashcode, NO_INSERT);
5574 return ((shared_bitmap_info_t) *slot)->pt_vars;
5578 /* Add a bitmap to the shared bitmap hashtable. */
5581 shared_bitmap_add (bitmap pt_vars)
5584 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5586 sbi->pt_vars = pt_vars;
5587 sbi->hashcode = bitmap_hash (pt_vars);
5589 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5590 sbi->hashcode, INSERT);
5591 gcc_assert (!*slot);
5592 *slot = (void *) sbi;
5596 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5599 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5604 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5606 varinfo_t vi = get_varinfo (i);
5608 /* The only artificial variables that are allowed in a may-alias
5609 set are heap variables. */
5610 if (vi->is_artificial_var && !vi->is_heap_var)
5613 if (TREE_CODE (vi->decl) == VAR_DECL
5614 || TREE_CODE (vi->decl) == PARM_DECL
5615 || TREE_CODE (vi->decl) == RESULT_DECL)
5617 /* If we are in IPA mode we will not recompute points-to
5618 sets after inlining so make sure they stay valid. */
5620 && !DECL_PT_UID_SET_P (vi->decl))
5621 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5623 /* Add the decl to the points-to set. Note that the points-to
5624 set contains global variables. */
5625 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5626 if (vi->is_global_var)
5627 pt->vars_contains_global = true;
5633 /* Compute the points-to solution *PT for the variable VI. */
5636 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5640 bitmap finished_solution;
5644 memset (pt, 0, sizeof (struct pt_solution));
5646 /* This variable may have been collapsed, let's get the real
5648 vi = get_varinfo (find (orig_vi->id));
5650 /* Translate artificial variables into SSA_NAME_PTR_INFO
5652 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5654 varinfo_t vi = get_varinfo (i);
5656 if (vi->is_artificial_var)
5658 if (vi->id == nothing_id)
5660 else if (vi->id == escaped_id)
5663 pt->ipa_escaped = 1;
5667 else if (vi->id == nonlocal_id)
5669 else if (vi->is_heap_var)
5670 /* We represent heapvars in the points-to set properly. */
5672 else if (vi->id == readonly_id)
5675 else if (vi->id == anything_id
5676 || vi->id == integer_id)
5679 if (vi->is_restrict_var)
5680 pt->vars_contains_restrict = true;
5683 /* Instead of doing extra work, simply do not create
5684 elaborate points-to information for pt_anything pointers. */
5686 && (orig_vi->is_artificial_var
5687 || !pt->vars_contains_restrict))
5690 /* Share the final set of variables when possible. */
5691 finished_solution = BITMAP_GGC_ALLOC ();
5692 stats.points_to_sets_created++;
5694 set_uids_in_ptset (finished_solution, vi->solution, pt);
5695 result = shared_bitmap_lookup (finished_solution);
5698 shared_bitmap_add (finished_solution);
5699 pt->vars = finished_solution;
5704 bitmap_clear (finished_solution);
5708 /* Given a pointer variable P, fill in its points-to set. */
5711 find_what_p_points_to (tree p)
5713 struct ptr_info_def *pi;
5717 /* For parameters, get at the points-to set for the actual parm
5719 if (TREE_CODE (p) == SSA_NAME
5720 && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5721 && SSA_NAME_IS_DEFAULT_DEF (p))
5722 lookup_p = SSA_NAME_VAR (p);
5724 vi = lookup_vi_for_tree (lookup_p);
5728 pi = get_ptr_info (p);
5729 find_what_var_points_to (vi, &pi->pt);
5733 /* Query statistics for points-to solutions. */
5736 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5737 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5738 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5739 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5743 dump_pta_stats (FILE *s)
5745 fprintf (s, "\nPTA query stats:\n");
5746 fprintf (s, " pt_solution_includes: "
5747 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5748 HOST_WIDE_INT_PRINT_DEC" queries\n",
5749 pta_stats.pt_solution_includes_no_alias,
5750 pta_stats.pt_solution_includes_no_alias
5751 + pta_stats.pt_solution_includes_may_alias);
5752 fprintf (s, " pt_solutions_intersect: "
5753 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5754 HOST_WIDE_INT_PRINT_DEC" queries\n",
5755 pta_stats.pt_solutions_intersect_no_alias,
5756 pta_stats.pt_solutions_intersect_no_alias
5757 + pta_stats.pt_solutions_intersect_may_alias);
5761 /* Reset the points-to solution *PT to a conservative default
5762 (point to anything). */
5765 pt_solution_reset (struct pt_solution *pt)
5767 memset (pt, 0, sizeof (struct pt_solution));
5768 pt->anything = true;
5771 /* Set the points-to solution *PT to point only to the variables
5772 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5773 global variables and VARS_CONTAINS_RESTRICT specifies whether
5774 it contains restrict tag variables. */
5777 pt_solution_set (struct pt_solution *pt, bitmap vars,
5778 bool vars_contains_global, bool vars_contains_restrict)
5780 memset (pt, 0, sizeof (struct pt_solution));
5782 pt->vars_contains_global = vars_contains_global;
5783 pt->vars_contains_restrict = vars_contains_restrict;
5786 /* Computes the union of the points-to solutions *DEST and *SRC and
5787 stores the result in *DEST. This changes the points-to bitmap
5788 of *DEST and thus may not be used if that might be shared.
5789 The points-to bitmap of *SRC and *DEST will not be shared after
5790 this function if they were not before. */
5793 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5795 dest->anything |= src->anything;
5798 pt_solution_reset (dest);
5802 dest->nonlocal |= src->nonlocal;
5803 dest->escaped |= src->escaped;
5804 dest->ipa_escaped |= src->ipa_escaped;
5805 dest->null |= src->null;
5806 dest->vars_contains_global |= src->vars_contains_global;
5807 dest->vars_contains_restrict |= src->vars_contains_restrict;
5812 dest->vars = BITMAP_GGC_ALLOC ();
5813 bitmap_ior_into (dest->vars, src->vars);
5816 /* Return true if the points-to solution *PT is empty. */
5819 pt_solution_empty_p (struct pt_solution *pt)
5826 && !bitmap_empty_p (pt->vars))
5829 /* If the solution includes ESCAPED, check if that is empty. */
5831 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5834 /* If the solution includes ESCAPED, check if that is empty. */
5836 && !pt_solution_empty_p (&ipa_escaped_pt))
5842 /* Return true if the points-to solution *PT includes global memory. */
5845 pt_solution_includes_global (struct pt_solution *pt)
5849 || pt->vars_contains_global)
5853 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5855 if (pt->ipa_escaped)
5856 return pt_solution_includes_global (&ipa_escaped_pt);
5858 /* ??? This predicate is not correct for the IPA-PTA solution
5859 as we do not properly distinguish between unit escape points
5860 and global variables. */
5861 if (cfun->gimple_df->ipa_pta)
5867 /* Return true if the points-to solution *PT includes the variable
5868 declaration DECL. */
5871 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5877 && is_global_var (decl))
5881 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5884 /* If the solution includes ESCAPED, check it. */
5886 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5889 /* If the solution includes ESCAPED, check it. */
5891 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5898 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5900 bool res = pt_solution_includes_1 (pt, decl);
5902 ++pta_stats.pt_solution_includes_may_alias;
5904 ++pta_stats.pt_solution_includes_no_alias;
5908 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5912 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5914 if (pt1->anything || pt2->anything)
5917 /* If either points to unknown global memory and the other points to
5918 any global memory they alias. */
5921 || pt2->vars_contains_global))
5923 && pt1->vars_contains_global))
5926 /* Check the escaped solution if required. */
5927 if ((pt1->escaped || pt2->escaped)
5928 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5930 /* If both point to escaped memory and that solution
5931 is not empty they alias. */
5932 if (pt1->escaped && pt2->escaped)
5935 /* If either points to escaped memory see if the escaped solution
5936 intersects with the other. */
5938 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5940 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
5944 /* Check the escaped solution if required.
5945 ??? Do we need to check the local against the IPA escaped sets? */
5946 if ((pt1->ipa_escaped || pt2->ipa_escaped)
5947 && !pt_solution_empty_p (&ipa_escaped_pt))
5949 /* If both point to escaped memory and that solution
5950 is not empty they alias. */
5951 if (pt1->ipa_escaped && pt2->ipa_escaped)
5954 /* If either points to escaped memory see if the escaped solution
5955 intersects with the other. */
5956 if ((pt1->ipa_escaped
5957 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
5958 || (pt2->ipa_escaped
5959 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
5963 /* Now both pointers alias if their points-to solution intersects. */
5966 && bitmap_intersect_p (pt1->vars, pt2->vars));
5970 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
5972 bool res = pt_solutions_intersect_1 (pt1, pt2);
5974 ++pta_stats.pt_solutions_intersect_may_alias;
5976 ++pta_stats.pt_solutions_intersect_no_alias;
5980 /* Return true if both points-to solutions PT1 and PT2 for two restrict
5981 qualified pointers are possibly based on the same pointer. */
5984 pt_solutions_same_restrict_base (struct pt_solution *pt1,
5985 struct pt_solution *pt2)
5987 /* If we deal with points-to solutions of two restrict qualified
5988 pointers solely rely on the pointed-to variable bitmap intersection.
5989 For two pointers that are based on each other the bitmaps will
5991 if (pt1->vars_contains_restrict
5992 && pt2->vars_contains_restrict)
5994 gcc_assert (pt1->vars && pt2->vars);
5995 return bitmap_intersect_p (pt1->vars, pt2->vars);
6002 /* Dump points-to information to OUTFILE. */
6005 dump_sa_points_to_info (FILE *outfile)
6009 fprintf (outfile, "\nPoints-to sets\n\n");
6011 if (dump_flags & TDF_STATS)
6013 fprintf (outfile, "Stats:\n");
6014 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6015 fprintf (outfile, "Non-pointer vars: %d\n",
6016 stats.nonpointer_vars);
6017 fprintf (outfile, "Statically unified vars: %d\n",
6018 stats.unified_vars_static);
6019 fprintf (outfile, "Dynamically unified vars: %d\n",
6020 stats.unified_vars_dynamic);
6021 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6022 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6023 fprintf (outfile, "Number of implicit edges: %d\n",
6024 stats.num_implicit_edges);
6027 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6029 varinfo_t vi = get_varinfo (i);
6030 if (!vi->may_have_pointers)
6032 dump_solution_for_var (outfile, i);
6037 /* Debug points-to information to stderr. */
6040 debug_sa_points_to_info (void)
6042 dump_sa_points_to_info (stderr);
6046 /* Initialize the always-existing constraint variables for NULL
6047 ANYTHING, READONLY, and INTEGER */
6050 init_base_vars (void)
6052 struct constraint_expr lhs, rhs;
6053 varinfo_t var_anything;
6054 varinfo_t var_nothing;
6055 varinfo_t var_readonly;
6056 varinfo_t var_escaped;
6057 varinfo_t var_nonlocal;
6058 varinfo_t var_storedanything;
6059 varinfo_t var_integer;
6061 /* Create the NULL variable, used to represent that a variable points
6063 var_nothing = new_var_info (NULL_TREE, "NULL");
6064 gcc_assert (var_nothing->id == nothing_id);
6065 var_nothing->is_artificial_var = 1;
6066 var_nothing->offset = 0;
6067 var_nothing->size = ~0;
6068 var_nothing->fullsize = ~0;
6069 var_nothing->is_special_var = 1;
6070 var_nothing->may_have_pointers = 0;
6071 var_nothing->is_global_var = 0;
6073 /* Create the ANYTHING variable, used to represent that a variable
6074 points to some unknown piece of memory. */
6075 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6076 gcc_assert (var_anything->id == anything_id);
6077 var_anything->is_artificial_var = 1;
6078 var_anything->size = ~0;
6079 var_anything->offset = 0;
6080 var_anything->next = NULL;
6081 var_anything->fullsize = ~0;
6082 var_anything->is_special_var = 1;
6084 /* Anything points to anything. This makes deref constraints just
6085 work in the presence of linked list and other p = *p type loops,
6086 by saying that *ANYTHING = ANYTHING. */
6088 lhs.var = anything_id;
6090 rhs.type = ADDRESSOF;
6091 rhs.var = anything_id;
6094 /* This specifically does not use process_constraint because
6095 process_constraint ignores all anything = anything constraints, since all
6096 but this one are redundant. */
6097 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6099 /* Create the READONLY variable, used to represent that a variable
6100 points to readonly memory. */
6101 var_readonly = new_var_info (NULL_TREE, "READONLY");
6102 gcc_assert (var_readonly->id == readonly_id);
6103 var_readonly->is_artificial_var = 1;
6104 var_readonly->offset = 0;
6105 var_readonly->size = ~0;
6106 var_readonly->fullsize = ~0;
6107 var_readonly->next = NULL;
6108 var_readonly->is_special_var = 1;
6110 /* readonly memory points to anything, in order to make deref
6111 easier. In reality, it points to anything the particular
6112 readonly variable can point to, but we don't track this
6115 lhs.var = readonly_id;
6117 rhs.type = ADDRESSOF;
6118 rhs.var = readonly_id; /* FIXME */
6120 process_constraint (new_constraint (lhs, rhs));
6122 /* Create the ESCAPED variable, used to represent the set of escaped
6124 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6125 gcc_assert (var_escaped->id == escaped_id);
6126 var_escaped->is_artificial_var = 1;
6127 var_escaped->offset = 0;
6128 var_escaped->size = ~0;
6129 var_escaped->fullsize = ~0;
6130 var_escaped->is_special_var = 0;
6132 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6134 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6135 gcc_assert (var_nonlocal->id == nonlocal_id);
6136 var_nonlocal->is_artificial_var = 1;
6137 var_nonlocal->offset = 0;
6138 var_nonlocal->size = ~0;
6139 var_nonlocal->fullsize = ~0;
6140 var_nonlocal->is_special_var = 1;
6142 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6144 lhs.var = escaped_id;
6147 rhs.var = escaped_id;
6149 process_constraint (new_constraint (lhs, rhs));
6151 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6152 whole variable escapes. */
6154 lhs.var = escaped_id;
6157 rhs.var = escaped_id;
6158 rhs.offset = UNKNOWN_OFFSET;
6159 process_constraint (new_constraint (lhs, rhs));
6161 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6162 everything pointed to by escaped points to what global memory can
6165 lhs.var = escaped_id;
6168 rhs.var = nonlocal_id;
6170 process_constraint (new_constraint (lhs, rhs));
6172 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6173 global memory may point to global memory and escaped memory. */
6175 lhs.var = nonlocal_id;
6177 rhs.type = ADDRESSOF;
6178 rhs.var = nonlocal_id;
6180 process_constraint (new_constraint (lhs, rhs));
6181 rhs.type = ADDRESSOF;
6182 rhs.var = escaped_id;
6184 process_constraint (new_constraint (lhs, rhs));
6186 /* Create the STOREDANYTHING variable, used to represent the set of
6187 variables stored to *ANYTHING. */
6188 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6189 gcc_assert (var_storedanything->id == storedanything_id);
6190 var_storedanything->is_artificial_var = 1;
6191 var_storedanything->offset = 0;
6192 var_storedanything->size = ~0;
6193 var_storedanything->fullsize = ~0;
6194 var_storedanything->is_special_var = 0;
6196 /* Create the INTEGER variable, used to represent that a variable points
6197 to what an INTEGER "points to". */
6198 var_integer = new_var_info (NULL_TREE, "INTEGER");
6199 gcc_assert (var_integer->id == integer_id);
6200 var_integer->is_artificial_var = 1;
6201 var_integer->size = ~0;
6202 var_integer->fullsize = ~0;
6203 var_integer->offset = 0;
6204 var_integer->next = NULL;
6205 var_integer->is_special_var = 1;
6207 /* INTEGER = ANYTHING, because we don't know where a dereference of
6208 a random integer will point to. */
6210 lhs.var = integer_id;
6212 rhs.type = ADDRESSOF;
6213 rhs.var = anything_id;
6215 process_constraint (new_constraint (lhs, rhs));
6218 /* Initialize things necessary to perform PTA */
6221 init_alias_vars (void)
6223 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6225 bitmap_obstack_initialize (&pta_obstack);
6226 bitmap_obstack_initialize (&oldpta_obstack);
6227 bitmap_obstack_initialize (&predbitmap_obstack);
6229 constraint_pool = create_alloc_pool ("Constraint pool",
6230 sizeof (struct constraint), 30);
6231 variable_info_pool = create_alloc_pool ("Variable info pool",
6232 sizeof (struct variable_info), 30);
6233 constraints = VEC_alloc (constraint_t, heap, 8);
6234 varmap = VEC_alloc (varinfo_t, heap, 8);
6235 vi_for_tree = pointer_map_create ();
6236 call_stmt_vars = pointer_map_create ();
6238 memset (&stats, 0, sizeof (stats));
6239 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6240 shared_bitmap_eq, free);
6244 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6245 predecessor edges. */
6248 remove_preds_and_fake_succs (constraint_graph_t graph)
6252 /* Clear the implicit ref and address nodes from the successor
6254 for (i = 0; i < FIRST_REF_NODE; i++)
6256 if (graph->succs[i])
6257 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6258 FIRST_REF_NODE * 2);
6261 /* Free the successor list for the non-ref nodes. */
6262 for (i = FIRST_REF_NODE; i < graph->size; i++)
6264 if (graph->succs[i])
6265 BITMAP_FREE (graph->succs[i]);
6268 /* Now reallocate the size of the successor list as, and blow away
6269 the predecessor bitmaps. */
6270 graph->size = VEC_length (varinfo_t, varmap);
6271 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6273 free (graph->implicit_preds);
6274 graph->implicit_preds = NULL;
6275 free (graph->preds);
6276 graph->preds = NULL;
6277 bitmap_obstack_release (&predbitmap_obstack);
6280 /* Initialize the heapvar for statement mapping. */
6283 init_alias_heapvars (void)
6285 if (!heapvar_for_stmt)
6286 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6290 /* Delete the heapvar for statement mapping. */
6293 delete_alias_heapvars (void)
6295 if (heapvar_for_stmt)
6296 htab_delete (heapvar_for_stmt);
6297 heapvar_for_stmt = NULL;
6300 /* Solve the constraint set. */
6303 solve_constraints (void)
6305 struct scc_info *si;
6309 "\nCollapsing static cycles and doing variable "
6312 init_graph (VEC_length (varinfo_t, varmap) * 2);
6315 fprintf (dump_file, "Building predecessor graph\n");
6316 build_pred_graph ();
6319 fprintf (dump_file, "Detecting pointer and location "
6321 si = perform_var_substitution (graph);
6324 fprintf (dump_file, "Rewriting constraints and unifying "
6326 rewrite_constraints (graph, si);
6328 build_succ_graph ();
6329 free_var_substitution_info (si);
6331 if (dump_file && (dump_flags & TDF_GRAPH))
6332 dump_constraint_graph (dump_file);
6334 move_complex_constraints (graph);
6337 fprintf (dump_file, "Uniting pointer but not location equivalent "
6339 unite_pointer_equivalences (graph);
6342 fprintf (dump_file, "Finding indirect cycles\n");
6343 find_indirect_cycles (graph);
6345 /* Implicit nodes and predecessors are no longer necessary at this
6347 remove_preds_and_fake_succs (graph);
6350 fprintf (dump_file, "Solving graph\n");
6352 solve_graph (graph);
6355 dump_sa_points_to_info (dump_file);
6358 /* Create points-to sets for the current function. See the comments
6359 at the start of the file for an algorithmic overview. */
6362 compute_points_to_sets (void)
6368 timevar_push (TV_TREE_PTA);
6371 init_alias_heapvars ();
6373 intra_create_variable_infos ();
6375 /* Now walk all statements and build the constraint set. */
6378 gimple_stmt_iterator gsi;
6380 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6382 gimple phi = gsi_stmt (gsi);
6384 if (is_gimple_reg (gimple_phi_result (phi)))
6385 find_func_aliases (phi);
6388 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6390 gimple stmt = gsi_stmt (gsi);
6392 find_func_aliases (stmt);
6398 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6399 dump_constraints (dump_file, 0);
6402 /* From the constraints compute the points-to sets. */
6403 solve_constraints ();
6405 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6406 find_what_var_points_to (get_varinfo (escaped_id),
6407 &cfun->gimple_df->escaped);
6409 /* Make sure the ESCAPED solution (which is used as placeholder in
6410 other solutions) does not reference itself. This simplifies
6411 points-to solution queries. */
6412 cfun->gimple_df->escaped.escaped = 0;
6414 /* Mark escaped HEAP variables as global. */
6415 for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); ++i)
6417 && !vi->is_restrict_var
6418 && !vi->is_global_var)
6419 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6420 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6422 /* Compute the points-to sets for pointer SSA_NAMEs. */
6423 for (i = 0; i < num_ssa_names; ++i)
6425 tree ptr = ssa_name (i);
6427 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6428 find_what_p_points_to (ptr);
6431 /* Compute the call-used/clobbered sets. */
6434 gimple_stmt_iterator gsi;
6436 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6438 gimple stmt = gsi_stmt (gsi);
6439 struct pt_solution *pt;
6440 if (!is_gimple_call (stmt))
6443 pt = gimple_call_use_set (stmt);
6444 if (gimple_call_flags (stmt) & ECF_CONST)
6445 memset (pt, 0, sizeof (struct pt_solution));
6446 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6448 find_what_var_points_to (vi, pt);
6449 /* Escaped (and thus nonlocal) variables are always
6450 implicitly used by calls. */
6451 /* ??? ESCAPED can be empty even though NONLOCAL
6458 /* If there is nothing special about this call then
6459 we have made everything that is used also escape. */
6460 *pt = cfun->gimple_df->escaped;
6464 pt = gimple_call_clobber_set (stmt);
6465 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6466 memset (pt, 0, sizeof (struct pt_solution));
6467 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6469 find_what_var_points_to (vi, pt);
6470 /* Escaped (and thus nonlocal) variables are always
6471 implicitly clobbered by calls. */
6472 /* ??? ESCAPED can be empty even though NONLOCAL
6479 /* If there is nothing special about this call then
6480 we have made everything that is used also escape. */
6481 *pt = cfun->gimple_df->escaped;
6487 timevar_pop (TV_TREE_PTA);
6491 /* Delete created points-to sets. */
6494 delete_points_to_sets (void)
6498 htab_delete (shared_bitmap_table);
6499 if (dump_file && (dump_flags & TDF_STATS))
6500 fprintf (dump_file, "Points to sets created:%d\n",
6501 stats.points_to_sets_created);
6503 pointer_map_destroy (vi_for_tree);
6504 pointer_map_destroy (call_stmt_vars);
6505 bitmap_obstack_release (&pta_obstack);
6506 VEC_free (constraint_t, heap, constraints);
6508 for (i = 0; i < graph->size; i++)
6509 VEC_free (constraint_t, heap, graph->complex[i]);
6510 free (graph->complex);
6513 free (graph->succs);
6515 free (graph->pe_rep);
6516 free (graph->indirect_cycles);
6519 VEC_free (varinfo_t, heap, varmap);
6520 free_alloc_pool (variable_info_pool);
6521 free_alloc_pool (constraint_pool);
6525 /* Compute points-to information for every SSA_NAME pointer in the
6526 current function and compute the transitive closure of escaped
6527 variables to re-initialize the call-clobber states of local variables. */
6530 compute_may_aliases (void)
6532 if (cfun->gimple_df->ipa_pta)
6536 fprintf (dump_file, "\nNot re-computing points-to information "
6537 "because IPA points-to information is available.\n\n");
6539 /* But still dump what we have remaining it. */
6540 dump_alias_info (dump_file);
6542 if (dump_flags & TDF_DETAILS)
6543 dump_referenced_vars (dump_file);
6549 /* For each pointer P_i, determine the sets of variables that P_i may
6550 point-to. Compute the reachability set of escaped and call-used
6552 compute_points_to_sets ();
6554 /* Debugging dumps. */
6557 dump_alias_info (dump_file);
6559 if (dump_flags & TDF_DETAILS)
6560 dump_referenced_vars (dump_file);
6563 /* Deallocate memory used by aliasing data structures and the internal
6564 points-to solution. */
6565 delete_points_to_sets ();
6567 gcc_assert (!need_ssa_update_p (cfun));
6573 gate_tree_pta (void)
6575 return flag_tree_pta;
6578 /* A dummy pass to cause points-to information to be computed via
6579 TODO_rebuild_alias. */
6581 struct gimple_opt_pass pass_build_alias =
6586 gate_tree_pta, /* gate */
6590 0, /* static_pass_number */
6591 TV_NONE, /* tv_id */
6592 PROP_cfg | PROP_ssa, /* properties_required */
6593 0, /* properties_provided */
6594 0, /* properties_destroyed */
6595 0, /* todo_flags_start */
6596 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6600 /* A dummy pass to cause points-to information to be computed via
6601 TODO_rebuild_alias. */
6603 struct gimple_opt_pass pass_build_ealias =
6607 "ealias", /* name */
6608 gate_tree_pta, /* gate */
6612 0, /* static_pass_number */
6613 TV_NONE, /* tv_id */
6614 PROP_cfg | PROP_ssa, /* properties_required */
6615 0, /* properties_provided */
6616 0, /* properties_destroyed */
6617 0, /* todo_flags_start */
6618 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6623 /* Return true if we should execute IPA PTA. */
6629 /* Don't bother doing anything if the program has errors. */
6630 && !(errorcount || sorrycount));
6633 /* IPA PTA solutions for ESCAPED. */
6634 struct pt_solution ipa_escaped_pt
6635 = { true, false, false, false, false, false, false, NULL };
6637 /* Execute the driver for IPA PTA. */
6639 ipa_pta_execute (void)
6641 struct cgraph_node *node;
6642 struct varpool_node *var;
6647 init_alias_heapvars ();
6650 /* Build the constraints. */
6651 for (node = cgraph_nodes; node; node = node->next)
6653 struct cgraph_node *alias;
6656 /* Nodes without a body are not interesting. Especially do not
6657 visit clones at this point for now - we get duplicate decls
6658 there for inline clones at least. */
6659 if (!gimple_has_body_p (node->decl)
6663 vi = create_function_info_for (node->decl,
6664 alias_get_name (node->decl));
6666 /* Associate the varinfo node with all aliases. */
6667 for (alias = node->same_body; alias; alias = alias->next)
6668 insert_vi_for_tree (alias->decl, vi);
6671 /* Create constraints for global variables and their initializers. */
6672 for (var = varpool_nodes; var; var = var->next)
6674 struct varpool_node *alias;
6677 vi = get_vi_for_tree (var->decl);
6679 /* Associate the varinfo node with all aliases. */
6680 for (alias = var->extra_name; alias; alias = alias->next)
6681 insert_vi_for_tree (alias->decl, vi);
6687 "Generating constraints for global initializers\n\n");
6688 dump_constraints (dump_file, 0);
6689 fprintf (dump_file, "\n");
6691 from = VEC_length (constraint_t, constraints);
6693 for (node = cgraph_nodes; node; node = node->next)
6695 struct function *func;
6699 /* Nodes without a body are not interesting. */
6700 if (!gimple_has_body_p (node->decl)
6707 "Generating constraints for %s", cgraph_node_name (node));
6708 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6709 fprintf (dump_file, " (%s)",
6710 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6711 fprintf (dump_file, "\n");
6714 func = DECL_STRUCT_FUNCTION (node->decl);
6715 old_func_decl = current_function_decl;
6717 current_function_decl = node->decl;
6719 /* For externally visible functions use local constraints for
6720 their arguments. For local functions we see all callers
6721 and thus do not need initial constraints for parameters. */
6722 if (node->local.externally_visible)
6723 intra_create_variable_infos ();
6725 /* Build constriants for the function body. */
6726 FOR_EACH_BB_FN (bb, func)
6728 gimple_stmt_iterator gsi;
6730 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6733 gimple phi = gsi_stmt (gsi);
6735 if (is_gimple_reg (gimple_phi_result (phi)))
6736 find_func_aliases (phi);
6739 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6741 gimple stmt = gsi_stmt (gsi);
6743 find_func_aliases (stmt);
6744 find_func_clobbers (stmt);
6748 current_function_decl = old_func_decl;
6753 fprintf (dump_file, "\n");
6754 dump_constraints (dump_file, from);
6755 fprintf (dump_file, "\n");
6757 from = VEC_length (constraint_t, constraints);
6760 /* From the constraints compute the points-to sets. */
6761 solve_constraints ();
6763 /* Compute the global points-to sets for ESCAPED.
6764 ??? Note that the computed escape set is not correct
6765 for the whole unit as we fail to consider graph edges to
6766 externally visible functions. */
6767 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6769 /* Make sure the ESCAPED solution (which is used as placeholder in
6770 other solutions) does not reference itself. This simplifies
6771 points-to solution queries. */
6772 ipa_escaped_pt.ipa_escaped = 0;
6774 /* Assign the points-to sets to the SSA names in the unit. */
6775 for (node = cgraph_nodes; node; node = node->next)
6778 struct function *fn;
6782 struct pt_solution uses, clobbers;
6783 struct cgraph_edge *e;
6785 /* Nodes without a body are not interesting. */
6786 if (!gimple_has_body_p (node->decl)
6790 fn = DECL_STRUCT_FUNCTION (node->decl);
6792 /* Compute the points-to sets for pointer SSA_NAMEs. */
6793 for (i = 0; VEC_iterate (tree, fn->gimple_df->ssa_names, i, ptr); ++i)
6796 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6797 find_what_p_points_to (ptr);
6800 /* Compute the call-use and call-clobber sets for all direct calls. */
6801 fi = lookup_vi_for_tree (node->decl);
6802 gcc_assert (fi->is_fn_info);
6803 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6805 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6806 for (e = node->callers; e; e = e->next_caller)
6811 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6812 *gimple_call_use_set (e->call_stmt) = uses;
6815 /* Compute the call-use and call-clobber sets for indirect calls
6816 and calls to external functions. */
6817 FOR_EACH_BB_FN (bb, fn)
6819 gimple_stmt_iterator gsi;
6821 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6823 gimple stmt = gsi_stmt (gsi);
6824 struct pt_solution *pt;
6828 if (!is_gimple_call (stmt))
6831 /* Handle direct calls to external functions. */
6832 decl = gimple_call_fndecl (stmt);
6834 && (!(fi = lookup_vi_for_tree (decl))
6835 || !fi->is_fn_info))
6837 pt = gimple_call_use_set (stmt);
6838 if (gimple_call_flags (stmt) & ECF_CONST)
6839 memset (pt, 0, sizeof (struct pt_solution));
6840 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6842 find_what_var_points_to (vi, pt);
6843 /* Escaped (and thus nonlocal) variables are always
6844 implicitly used by calls. */
6845 /* ??? ESCAPED can be empty even though NONLOCAL
6848 pt->ipa_escaped = 1;
6852 /* If there is nothing special about this call then
6853 we have made everything that is used also escape. */
6854 *pt = ipa_escaped_pt;
6858 pt = gimple_call_clobber_set (stmt);
6859 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6860 memset (pt, 0, sizeof (struct pt_solution));
6861 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6863 find_what_var_points_to (vi, pt);
6864 /* Escaped (and thus nonlocal) variables are always
6865 implicitly clobbered by calls. */
6866 /* ??? ESCAPED can be empty even though NONLOCAL
6869 pt->ipa_escaped = 1;
6873 /* If there is nothing special about this call then
6874 we have made everything that is used also escape. */
6875 *pt = ipa_escaped_pt;
6880 /* Handle indirect calls. */
6882 && (fi = get_fi_for_callee (stmt)))
6884 /* We need to accumulate all clobbers/uses of all possible
6886 fi = get_varinfo (find (fi->id));
6887 /* If we cannot constrain the set of functions we'll end up
6888 calling we end up using/clobbering everything. */
6889 if (bitmap_bit_p (fi->solution, anything_id)
6890 || bitmap_bit_p (fi->solution, nonlocal_id)
6891 || bitmap_bit_p (fi->solution, escaped_id))
6893 pt_solution_reset (gimple_call_clobber_set (stmt));
6894 pt_solution_reset (gimple_call_use_set (stmt));
6900 struct pt_solution *uses, *clobbers;
6902 uses = gimple_call_use_set (stmt);
6903 clobbers = gimple_call_clobber_set (stmt);
6904 memset (uses, 0, sizeof (struct pt_solution));
6905 memset (clobbers, 0, sizeof (struct pt_solution));
6906 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6908 struct pt_solution sol;
6910 vi = get_varinfo (i);
6911 if (!vi->is_fn_info)
6913 /* ??? We could be more precise here? */
6915 uses->ipa_escaped = 1;
6916 clobbers->nonlocal = 1;
6917 clobbers->ipa_escaped = 1;
6921 if (!uses->anything)
6923 find_what_var_points_to
6924 (first_vi_for_offset (vi, fi_uses), &sol);
6925 pt_solution_ior_into (uses, &sol);
6927 if (!clobbers->anything)
6929 find_what_var_points_to
6930 (first_vi_for_offset (vi, fi_clobbers), &sol);
6931 pt_solution_ior_into (clobbers, &sol);
6939 fn->gimple_df->ipa_pta = true;
6942 delete_points_to_sets ();
6949 struct simple_ipa_opt_pass pass_ipa_pta =
6954 gate_ipa_pta, /* gate */
6955 ipa_pta_execute, /* execute */
6958 0, /* static_pass_number */
6959 TV_IPA_PTA, /* tv_id */
6960 0, /* properties_required */
6961 0, /* properties_provided */
6962 0, /* properties_destroyed */
6963 0, /* todo_flags_start */
6964 TODO_update_ssa /* todo_flags_finish */
6969 #include "gt-tree-ssa-structalias.h"