1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dberlin@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "basic-block.h"
33 #include "tree-flow.h"
34 #include "tree-inline.h"
40 #include "tree-pass.h"
42 #include "alloc-pool.h"
43 #include "splay-tree.h"
47 #include "pointer-set.h"
49 /* The idea behind this analyzer is to generate set constraints from the
50 program, then solve the resulting constraints in order to generate the
53 Set constraints are a way of modeling program analysis problems that
54 involve sets. They consist of an inclusion constraint language,
55 describing the variables (each variable is a set) and operations that
56 are involved on the variables, and a set of rules that derive facts
57 from these operations. To solve a system of set constraints, you derive
58 all possible facts under the rules, which gives you the correct sets
61 See "Efficient Field-sensitive pointer analysis for C" by "David
62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
63 http://citeseer.ist.psu.edu/pearce04efficient.html
65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
67 http://citeseer.ist.psu.edu/heintze01ultrafast.html
69 There are three types of real constraint expressions, DEREF,
70 ADDRESSOF, and SCALAR. Each constraint expression consists
71 of a constraint type, a variable, and an offset.
73 SCALAR is a constraint expression type used to represent x, whether
74 it appears on the LHS or the RHS of a statement.
75 DEREF is a constraint expression type used to represent *x, whether
76 it appears on the LHS or the RHS of a statement.
77 ADDRESSOF is a constraint expression used to represent &x, whether
78 it appears on the LHS or the RHS of a statement.
80 Each pointer variable in the program is assigned an integer id, and
81 each field of a structure variable is assigned an integer id as well.
83 Structure variables are linked to their list of fields through a "next
84 field" in each variable that points to the next field in offset
86 Each variable for a structure field has
88 1. "size", that tells the size in bits of that field.
89 2. "fullsize, that tells the size in bits of the entire structure.
90 3. "offset", that tells the offset in bits from the beginning of the
91 structure to this field.
103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
108 In order to solve the system of set constraints, the following is
111 1. Each constraint variable x has a solution set associated with it,
114 2. Constraints are separated into direct, copy, and complex.
115 Direct constraints are ADDRESSOF constraints that require no extra
116 processing, such as P = &Q
117 Copy constraints are those of the form P = Q.
118 Complex constraints are all the constraints involving dereferences
119 and offsets (including offsetted copies).
121 3. All direct constraints of the form P = &Q are processed, such
122 that Q is added to Sol(P)
124 4. All complex constraints for a given constraint variable are stored in a
125 linked list attached to that variable's node.
127 5. A directed graph is built out of the copy constraints. Each
128 constraint variable is a node in the graph, and an edge from
129 Q to P is added for each copy constraint of the form P = Q
131 6. The graph is then walked, and solution sets are
132 propagated along the copy edges, such that an edge from Q to P
133 causes Sol(P) <- Sol(P) union Sol(Q).
135 7. As we visit each node, all complex constraints associated with
136 that node are processed by adding appropriate copy edges to the graph, or the
137 appropriate variables to the solution set.
139 8. The process of walking the graph is iterated until no solution
142 Prior to walking the graph in steps 6 and 7, We perform static
143 cycle elimination on the constraint graph, as well
144 as off-line variable substitution.
146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
147 on and turned into anything), but isn't. You can just see what offset
148 inside the pointed-to struct it's going to access.
150 TODO: Constant bounded arrays can be handled as if they were structs of the
151 same number of elements.
153 TODO: Modeling heap and incoming pointers becomes much better if we
154 add fields to them as we discover them, which we could do.
156 TODO: We could handle unions, but to be honest, it's probably not
157 worth the pain or slowdown. */
159 /* IPA-PTA optimizations possible.
161 When the indirect function called is ANYTHING we can add disambiguation
162 based on the function signatures (or simply the parameter count which
163 is the varinfo size). We also do not need to consider functions that
164 do not have their address taken.
166 The is_global_var bit which marks escape points is overly conservative
167 in IPA mode. Split it to is_escape_point and is_global_var - only
168 externally visible globals are escape points in IPA mode. This is
169 also needed to fix the pt_solution_includes_global predicate
170 (and thus ptr_deref_may_alias_global_p).
172 The way we introduce DECL_PT_UID to avoid fixing up all points-to
173 sets in the translation unit when we copy a DECL during inlining
174 pessimizes precision. The advantage is that the DECL_PT_UID keeps
175 compile-time and memory usage overhead low - the points-to sets
176 do not grow or get unshared as they would during a fixup phase.
177 An alternative solution is to delay IPA PTA until after all
178 inlining transformations have been applied.
180 The way we propagate clobber/use information isn't optimized.
181 It should use a new complex constraint that properly filters
182 out local variables of the callee (though that would make
183 the sets invalid after inlining). OTOH we might as well
184 admit defeat to WHOPR and simply do all the clobber/use analysis
185 and propagation after PTA finished but before we threw away
186 points-to information for memory variables. WHOPR and PTA
187 do not play along well anyway - the whole constraint solving
188 would need to be done in WPA phase and it will be very interesting
189 to apply the results to local SSA names during LTRANS phase.
191 We probably should compute a per-function unit-ESCAPE solution
192 propagating it simply like the clobber / uses solutions. The
193 solution can go alongside the non-IPA espaced solution and be
194 used to query which vars escape the unit through a function.
196 We never put function decls in points-to sets so we do not
197 keep the set of called functions for indirect calls.
199 And probably more. */
200 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct heapvar_map)))
201 htab_t heapvar_for_stmt;
203 static bool use_field_sensitive = true;
204 static int in_ipa_mode = 0;
206 /* Used for predecessor bitmaps. */
207 static bitmap_obstack predbitmap_obstack;
209 /* Used for points-to sets. */
210 static bitmap_obstack pta_obstack;
212 /* Used for oldsolution members of variables. */
213 static bitmap_obstack oldpta_obstack;
215 /* Used for per-solver-iteration bitmaps. */
216 static bitmap_obstack iteration_obstack;
218 static unsigned int create_variable_info_for (tree, const char *);
219 typedef struct constraint_graph *constraint_graph_t;
220 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
223 typedef struct constraint *constraint_t;
225 DEF_VEC_P(constraint_t);
226 DEF_VEC_ALLOC_P(constraint_t,heap);
228 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
230 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
232 static struct constraint_stats
234 unsigned int total_vars;
235 unsigned int nonpointer_vars;
236 unsigned int unified_vars_static;
237 unsigned int unified_vars_dynamic;
238 unsigned int iterations;
239 unsigned int num_edges;
240 unsigned int num_implicit_edges;
241 unsigned int points_to_sets_created;
246 /* ID of this variable */
249 /* True if this is a variable created by the constraint analysis, such as
250 heap variables and constraints we had to break up. */
251 unsigned int is_artificial_var : 1;
253 /* True if this is a special variable whose solution set should not be
255 unsigned int is_special_var : 1;
257 /* True for variables whose size is not known or variable. */
258 unsigned int is_unknown_size_var : 1;
260 /* True for (sub-)fields that represent a whole variable. */
261 unsigned int is_full_var : 1;
263 /* True if this is a heap variable. */
264 unsigned int is_heap_var : 1;
266 /* True if this is a variable tracking a restrict pointer source. */
267 unsigned int is_restrict_var : 1;
269 /* True if this field may contain pointers. */
270 unsigned int may_have_pointers : 1;
272 /* True if this field has only restrict qualified pointers. */
273 unsigned int only_restrict_pointers : 1;
275 /* True if this represents a global variable. */
276 unsigned int is_global_var : 1;
278 /* True if this represents a IPA function info. */
279 unsigned int is_fn_info : 1;
281 /* A link to the variable for the next field in this structure. */
282 struct variable_info *next;
284 /* Offset of this variable, in bits, from the base variable */
285 unsigned HOST_WIDE_INT offset;
287 /* Size of the variable, in bits. */
288 unsigned HOST_WIDE_INT size;
290 /* Full size of the base variable, in bits. */
291 unsigned HOST_WIDE_INT fullsize;
293 /* Name of this variable */
296 /* Tree that this variable is associated with. */
299 /* Points-to set for this variable. */
302 /* Old points-to set for this variable. */
305 typedef struct variable_info *varinfo_t;
307 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
308 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
309 unsigned HOST_WIDE_INT);
310 static varinfo_t lookup_vi_for_tree (tree);
312 /* Pool of variable info structures. */
313 static alloc_pool variable_info_pool;
315 DEF_VEC_P(varinfo_t);
317 DEF_VEC_ALLOC_P(varinfo_t, heap);
319 /* Table of variable info structures for constraint variables.
320 Indexed directly by variable info id. */
321 static VEC(varinfo_t,heap) *varmap;
323 /* Return the varmap element N */
325 static inline varinfo_t
326 get_varinfo (unsigned int n)
328 return VEC_index (varinfo_t, varmap, n);
331 /* Static IDs for the special variables. */
332 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
333 escaped_id = 3, nonlocal_id = 4,
334 storedanything_id = 5, integer_id = 6 };
336 struct GTY(()) heapvar_map {
338 unsigned HOST_WIDE_INT offset;
342 heapvar_map_eq (const void *p1, const void *p2)
344 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
345 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
346 return (h1->map.base.from == h2->map.base.from
347 && h1->offset == h2->offset);
351 heapvar_map_hash (struct heapvar_map *h)
353 return iterative_hash_host_wide_int (h->offset,
354 htab_hash_pointer (h->map.base.from));
357 /* Lookup a heap var for FROM, and return it if we find one. */
360 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
362 struct heapvar_map *h, in;
363 in.map.base.from = from;
365 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
366 heapvar_map_hash (&in));
372 /* Insert a mapping FROM->TO in the heap var for statement
376 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
378 struct heapvar_map *h;
381 h = ggc_alloc_heapvar_map ();
382 h->map.base.from = from;
384 h->map.hash = heapvar_map_hash (h);
386 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
387 gcc_assert (*loc == NULL);
388 *(struct heapvar_map **) loc = h;
391 /* Return a new variable info structure consisting for a variable
392 named NAME, and using constraint graph node NODE. Append it
393 to the vector of variable info structures. */
396 new_var_info (tree t, const char *name)
398 unsigned index = VEC_length (varinfo_t, varmap);
399 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
404 /* Vars without decl are artificial and do not have sub-variables. */
405 ret->is_artificial_var = (t == NULL_TREE);
406 ret->is_special_var = false;
407 ret->is_unknown_size_var = false;
408 ret->is_full_var = (t == NULL_TREE);
409 ret->is_heap_var = false;
410 ret->is_restrict_var = false;
411 ret->may_have_pointers = true;
412 ret->only_restrict_pointers = false;
413 ret->is_global_var = (t == NULL_TREE);
414 ret->is_fn_info = false;
416 ret->is_global_var = is_global_var (t);
417 ret->solution = BITMAP_ALLOC (&pta_obstack);
418 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
423 VEC_safe_push (varinfo_t, heap, varmap, ret);
429 /* A map mapping call statements to per-stmt variables for uses
430 and clobbers specific to the call. */
431 struct pointer_map_t *call_stmt_vars;
433 /* Lookup or create the variable for the call statement CALL. */
436 get_call_vi (gimple call)
441 slot_p = pointer_map_insert (call_stmt_vars, call);
443 return (varinfo_t) *slot_p;
445 vi = new_var_info (NULL_TREE, "CALLUSED");
449 vi->is_full_var = true;
451 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
455 vi2->is_full_var = true;
457 *slot_p = (void *) vi;
461 /* Lookup the variable for the call statement CALL representing
462 the uses. Returns NULL if there is nothing special about this call. */
465 lookup_call_use_vi (gimple call)
469 slot_p = pointer_map_contains (call_stmt_vars, call);
471 return (varinfo_t) *slot_p;
476 /* Lookup the variable for the call statement CALL representing
477 the clobbers. Returns NULL if there is nothing special about this call. */
480 lookup_call_clobber_vi (gimple call)
482 varinfo_t uses = lookup_call_use_vi (call);
489 /* Lookup or create the variable for the call statement CALL representing
493 get_call_use_vi (gimple call)
495 return get_call_vi (call);
498 /* Lookup or create the variable for the call statement CALL representing
501 static varinfo_t ATTRIBUTE_UNUSED
502 get_call_clobber_vi (gimple call)
504 return get_call_vi (call)->next;
508 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
510 /* An expression that appears in a constraint. */
512 struct constraint_expr
514 /* Constraint type. */
515 constraint_expr_type type;
517 /* Variable we are referring to in the constraint. */
520 /* Offset, in bits, of this constraint from the beginning of
521 variables it ends up referring to.
523 IOW, in a deref constraint, we would deref, get the result set,
524 then add OFFSET to each member. */
525 HOST_WIDE_INT offset;
528 /* Use 0x8000... as special unknown offset. */
529 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
531 typedef struct constraint_expr ce_s;
533 DEF_VEC_ALLOC_O(ce_s, heap);
534 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool);
535 static void get_constraint_for (tree, VEC(ce_s, heap) **);
536 static void do_deref (VEC (ce_s, heap) **);
538 /* Our set constraints are made up of two constraint expressions, one
541 As described in the introduction, our set constraints each represent an
542 operation between set valued variables.
546 struct constraint_expr lhs;
547 struct constraint_expr rhs;
550 /* List of constraints that we use to build the constraint graph from. */
552 static VEC(constraint_t,heap) *constraints;
553 static alloc_pool constraint_pool;
555 /* The constraint graph is represented as an array of bitmaps
556 containing successor nodes. */
558 struct constraint_graph
560 /* Size of this graph, which may be different than the number of
561 nodes in the variable map. */
564 /* Explicit successors of each node. */
567 /* Implicit predecessors of each node (Used for variable
569 bitmap *implicit_preds;
571 /* Explicit predecessors of each node (Used for variable substitution). */
574 /* Indirect cycle representatives, or -1 if the node has no indirect
576 int *indirect_cycles;
578 /* Representative node for a node. rep[a] == a unless the node has
582 /* Equivalence class representative for a label. This is used for
583 variable substitution. */
586 /* Pointer equivalence label for a node. All nodes with the same
587 pointer equivalence label can be unified together at some point
588 (either during constraint optimization or after the constraint
592 /* Pointer equivalence representative for a label. This is used to
593 handle nodes that are pointer equivalent but not location
594 equivalent. We can unite these once the addressof constraints
595 are transformed into initial points-to sets. */
598 /* Pointer equivalence label for each node, used during variable
600 unsigned int *pointer_label;
602 /* Location equivalence label for each node, used during location
603 equivalence finding. */
604 unsigned int *loc_label;
606 /* Pointed-by set for each node, used during location equivalence
607 finding. This is pointed-by rather than pointed-to, because it
608 is constructed using the predecessor graph. */
611 /* Points to sets for pointer equivalence. This is *not* the actual
612 points-to sets for nodes. */
615 /* Bitmap of nodes where the bit is set if the node is a direct
616 node. Used for variable substitution. */
617 sbitmap direct_nodes;
619 /* Bitmap of nodes where the bit is set if the node is address
620 taken. Used for variable substitution. */
621 bitmap address_taken;
623 /* Vector of complex constraints for each graph node. Complex
624 constraints are those involving dereferences or offsets that are
626 VEC(constraint_t,heap) **complex;
629 static constraint_graph_t graph;
631 /* During variable substitution and the offline version of indirect
632 cycle finding, we create nodes to represent dereferences and
633 address taken constraints. These represent where these start and
635 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
636 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
638 /* Return the representative node for NODE, if NODE has been unioned
640 This function performs path compression along the way to finding
641 the representative. */
644 find (unsigned int node)
646 gcc_assert (node < graph->size);
647 if (graph->rep[node] != node)
648 return graph->rep[node] = find (graph->rep[node]);
652 /* Union the TO and FROM nodes to the TO nodes.
653 Note that at some point in the future, we may want to do
654 union-by-rank, in which case we are going to have to return the
655 node we unified to. */
658 unite (unsigned int to, unsigned int from)
660 gcc_assert (to < graph->size && from < graph->size);
661 if (to != from && graph->rep[from] != to)
663 graph->rep[from] = to;
669 /* Create a new constraint consisting of LHS and RHS expressions. */
672 new_constraint (const struct constraint_expr lhs,
673 const struct constraint_expr rhs)
675 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
681 /* Print out constraint C to FILE. */
684 dump_constraint (FILE *file, constraint_t c)
686 if (c->lhs.type == ADDRESSOF)
688 else if (c->lhs.type == DEREF)
690 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
691 if (c->lhs.offset == UNKNOWN_OFFSET)
692 fprintf (file, " + UNKNOWN");
693 else if (c->lhs.offset != 0)
694 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
695 fprintf (file, " = ");
696 if (c->rhs.type == ADDRESSOF)
698 else if (c->rhs.type == DEREF)
700 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
701 if (c->rhs.offset == UNKNOWN_OFFSET)
702 fprintf (file, " + UNKNOWN");
703 else if (c->rhs.offset != 0)
704 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
705 fprintf (file, "\n");
709 void debug_constraint (constraint_t);
710 void debug_constraints (void);
711 void debug_constraint_graph (void);
712 void debug_solution_for_var (unsigned int);
713 void debug_sa_points_to_info (void);
715 /* Print out constraint C to stderr. */
718 debug_constraint (constraint_t c)
720 dump_constraint (stderr, c);
723 /* Print out all constraints to FILE */
726 dump_constraints (FILE *file, int from)
730 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
731 dump_constraint (file, c);
734 /* Print out all constraints to stderr. */
737 debug_constraints (void)
739 dump_constraints (stderr, 0);
742 /* Print out to FILE the edge in the constraint graph that is created by
743 constraint c. The edge may have a label, depending on the type of
744 constraint that it represents. If complex1, e.g: a = *b, then the label
745 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
746 complex with an offset, e.g: a = b + 8, then the label is "+".
747 Otherwise the edge has no label. */
750 dump_constraint_edge (FILE *file, constraint_t c)
752 if (c->rhs.type != ADDRESSOF)
754 const char *src = get_varinfo (c->rhs.var)->name;
755 const char *dst = get_varinfo (c->lhs.var)->name;
756 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
757 /* Due to preprocessing of constraints, instructions like *a = *b are
758 illegal; thus, we do not have to handle such cases. */
759 if (c->lhs.type == DEREF)
760 fprintf (file, " [ label=\"*=\" ] ;\n");
761 else if (c->rhs.type == DEREF)
762 fprintf (file, " [ label=\"=*\" ] ;\n");
765 /* We must check the case where the constraint is an offset.
766 In this case, it is treated as a complex constraint. */
767 if (c->rhs.offset != c->lhs.offset)
768 fprintf (file, " [ label=\"+\" ] ;\n");
770 fprintf (file, " ;\n");
775 /* Print the constraint graph in dot format. */
778 dump_constraint_graph (FILE *file)
780 unsigned int i=0, size;
783 /* Only print the graph if it has already been initialized: */
787 /* Print the constraints used to produce the constraint graph. The
788 constraints will be printed as comments in the dot file: */
789 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
790 dump_constraints (file, 0);
791 fprintf (file, "*/\n");
793 /* Prints the header of the dot file: */
794 fprintf (file, "\n\n// The constraint graph in dot format:\n");
795 fprintf (file, "strict digraph {\n");
796 fprintf (file, " node [\n shape = box\n ]\n");
797 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
798 fprintf (file, "\n // List of nodes in the constraint graph:\n");
800 /* The next lines print the nodes in the graph. In order to get the
801 number of nodes in the graph, we must choose the minimum between the
802 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
803 yet been initialized, then graph->size == 0, otherwise we must only
804 read nodes that have an entry in VEC (varinfo_t, varmap). */
805 size = VEC_length (varinfo_t, varmap);
806 size = size < graph->size ? size : graph->size;
807 for (i = 0; i < size; i++)
809 const char *name = get_varinfo (graph->rep[i])->name;
810 fprintf (file, " \"%s\" ;\n", name);
813 /* Go over the list of constraints printing the edges in the constraint
815 fprintf (file, "\n // The constraint edges:\n");
816 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
818 dump_constraint_edge (file, c);
820 /* Prints the tail of the dot file. By now, only the closing bracket. */
821 fprintf (file, "}\n\n\n");
824 /* Print out the constraint graph to stderr. */
827 debug_constraint_graph (void)
829 dump_constraint_graph (stderr);
834 The solver is a simple worklist solver, that works on the following
837 sbitmap changed_nodes = all zeroes;
839 For each node that is not already collapsed:
841 set bit in changed nodes
843 while (changed_count > 0)
845 compute topological ordering for constraint graph
847 find and collapse cycles in the constraint graph (updating
848 changed if necessary)
850 for each node (n) in the graph in topological order:
853 Process each complex constraint associated with the node,
854 updating changed if necessary.
856 For each outgoing edge from n, propagate the solution from n to
857 the destination of the edge, updating changed as necessary.
861 /* Return true if two constraint expressions A and B are equal. */
864 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
866 return a.type == b.type && a.var == b.var && a.offset == b.offset;
869 /* Return true if constraint expression A is less than constraint expression
870 B. This is just arbitrary, but consistent, in order to give them an
874 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
876 if (a.type == b.type)
879 return a.offset < b.offset;
881 return a.var < b.var;
884 return a.type < b.type;
887 /* Return true if constraint A is less than constraint B. This is just
888 arbitrary, but consistent, in order to give them an ordering. */
891 constraint_less (const constraint_t a, const constraint_t b)
893 if (constraint_expr_less (a->lhs, b->lhs))
895 else if (constraint_expr_less (b->lhs, a->lhs))
898 return constraint_expr_less (a->rhs, b->rhs);
901 /* Return true if two constraints A and B are equal. */
904 constraint_equal (struct constraint a, struct constraint b)
906 return constraint_expr_equal (a.lhs, b.lhs)
907 && constraint_expr_equal (a.rhs, b.rhs);
911 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
914 constraint_vec_find (VEC(constraint_t,heap) *vec,
915 struct constraint lookfor)
923 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
924 if (place >= VEC_length (constraint_t, vec))
926 found = VEC_index (constraint_t, vec, place);
927 if (!constraint_equal (*found, lookfor))
932 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
935 constraint_set_union (VEC(constraint_t,heap) **to,
936 VEC(constraint_t,heap) **from)
941 for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++)
943 if (constraint_vec_find (*to, *c) == NULL)
945 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
947 VEC_safe_insert (constraint_t, heap, *to, place, c);
952 /* Expands the solution in SET to all sub-fields of variables included.
953 Union the expanded result into RESULT. */
956 solution_set_expand (bitmap result, bitmap set)
962 /* In a first pass record all variables we need to add all
963 sub-fields off. This avoids quadratic behavior. */
964 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
966 varinfo_t v = get_varinfo (j);
967 if (v->is_artificial_var
970 v = lookup_vi_for_tree (v->decl);
972 vars = BITMAP_ALLOC (NULL);
973 bitmap_set_bit (vars, v->id);
976 /* In the second pass now do the addition to the solution and
977 to speed up solving add it to the delta as well. */
980 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
982 varinfo_t v = get_varinfo (j);
983 for (; v != NULL; v = v->next)
984 bitmap_set_bit (result, v->id);
990 /* Take a solution set SET, add OFFSET to each member of the set, and
991 overwrite SET with the result when done. */
994 solution_set_add (bitmap set, HOST_WIDE_INT offset)
996 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1000 /* If the offset is unknown we have to expand the solution to
1002 if (offset == UNKNOWN_OFFSET)
1004 solution_set_expand (set, set);
1008 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1010 varinfo_t vi = get_varinfo (i);
1012 /* If this is a variable with just one field just set its bit
1014 if (vi->is_artificial_var
1015 || vi->is_unknown_size_var
1017 bitmap_set_bit (result, i);
1020 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1022 /* If the offset makes the pointer point to before the
1023 variable use offset zero for the field lookup. */
1025 && fieldoffset > vi->offset)
1029 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1031 bitmap_set_bit (result, vi->id);
1032 /* If the result is not exactly at fieldoffset include the next
1033 field as well. See get_constraint_for_ptr_offset for more
1035 if (vi->offset != fieldoffset
1036 && vi->next != NULL)
1037 bitmap_set_bit (result, vi->next->id);
1041 bitmap_copy (set, result);
1042 BITMAP_FREE (result);
1045 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1049 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1052 return bitmap_ior_into (to, from);
1058 tmp = BITMAP_ALLOC (&iteration_obstack);
1059 bitmap_copy (tmp, from);
1060 solution_set_add (tmp, inc);
1061 res = bitmap_ior_into (to, tmp);
1067 /* Insert constraint C into the list of complex constraints for graph
1071 insert_into_complex (constraint_graph_t graph,
1072 unsigned int var, constraint_t c)
1074 VEC (constraint_t, heap) *complex = graph->complex[var];
1075 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1078 /* Only insert constraints that do not already exist. */
1079 if (place >= VEC_length (constraint_t, complex)
1080 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1081 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1085 /* Condense two variable nodes into a single variable node, by moving
1086 all associated info from SRC to TO. */
1089 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1095 gcc_assert (find (from) == to);
1097 /* Move all complex constraints from src node into to node */
1098 for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
1100 /* In complex constraints for node src, we may have either
1101 a = *src, and *src = a, or an offseted constraint which are
1102 always added to the rhs node's constraints. */
1104 if (c->rhs.type == DEREF)
1106 else if (c->lhs.type == DEREF)
1111 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1112 VEC_free (constraint_t, heap, graph->complex[from]);
1113 graph->complex[from] = NULL;
1117 /* Remove edges involving NODE from GRAPH. */
1120 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1122 if (graph->succs[node])
1123 BITMAP_FREE (graph->succs[node]);
1126 /* Merge GRAPH nodes FROM and TO into node TO. */
1129 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1132 if (graph->indirect_cycles[from] != -1)
1134 /* If we have indirect cycles with the from node, and we have
1135 none on the to node, the to node has indirect cycles from the
1136 from node now that they are unified.
1137 If indirect cycles exist on both, unify the nodes that they
1138 are in a cycle with, since we know they are in a cycle with
1140 if (graph->indirect_cycles[to] == -1)
1141 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1144 /* Merge all the successor edges. */
1145 if (graph->succs[from])
1147 if (!graph->succs[to])
1148 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1149 bitmap_ior_into (graph->succs[to],
1150 graph->succs[from]);
1153 clear_edges_for_node (graph, from);
1157 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1158 it doesn't exist in the graph already. */
1161 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1167 if (!graph->implicit_preds[to])
1168 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1170 if (bitmap_set_bit (graph->implicit_preds[to], from))
1171 stats.num_implicit_edges++;
1174 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1175 it doesn't exist in the graph already.
1176 Return false if the edge already existed, true otherwise. */
1179 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1182 if (!graph->preds[to])
1183 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1184 bitmap_set_bit (graph->preds[to], from);
1187 /* Add a graph edge to GRAPH, going from FROM to TO if
1188 it doesn't exist in the graph already.
1189 Return false if the edge already existed, true otherwise. */
1192 add_graph_edge (constraint_graph_t graph, unsigned int to,
1203 if (!graph->succs[from])
1204 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1205 if (bitmap_set_bit (graph->succs[from], to))
1208 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1216 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1219 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1222 return (graph->succs[dest]
1223 && bitmap_bit_p (graph->succs[dest], src));
1226 /* Initialize the constraint graph structure to contain SIZE nodes. */
1229 init_graph (unsigned int size)
1233 graph = XCNEW (struct constraint_graph);
1235 graph->succs = XCNEWVEC (bitmap, graph->size);
1236 graph->indirect_cycles = XNEWVEC (int, graph->size);
1237 graph->rep = XNEWVEC (unsigned int, graph->size);
1238 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1239 graph->pe = XCNEWVEC (unsigned int, graph->size);
1240 graph->pe_rep = XNEWVEC (int, graph->size);
1242 for (j = 0; j < graph->size; j++)
1245 graph->pe_rep[j] = -1;
1246 graph->indirect_cycles[j] = -1;
1250 /* Build the constraint graph, adding only predecessor edges right now. */
1253 build_pred_graph (void)
1259 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1260 graph->preds = XCNEWVEC (bitmap, graph->size);
1261 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1262 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1263 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1264 graph->points_to = XCNEWVEC (bitmap, graph->size);
1265 graph->eq_rep = XNEWVEC (int, graph->size);
1266 graph->direct_nodes = sbitmap_alloc (graph->size);
1267 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1268 sbitmap_zero (graph->direct_nodes);
1270 for (j = 0; j < FIRST_REF_NODE; j++)
1272 if (!get_varinfo (j)->is_special_var)
1273 SET_BIT (graph->direct_nodes, j);
1276 for (j = 0; j < graph->size; j++)
1277 graph->eq_rep[j] = -1;
1279 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1280 graph->indirect_cycles[j] = -1;
1282 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1284 struct constraint_expr lhs = c->lhs;
1285 struct constraint_expr rhs = c->rhs;
1286 unsigned int lhsvar = lhs.var;
1287 unsigned int rhsvar = rhs.var;
1289 if (lhs.type == DEREF)
1292 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1293 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1295 else if (rhs.type == DEREF)
1298 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1299 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1301 RESET_BIT (graph->direct_nodes, lhsvar);
1303 else if (rhs.type == ADDRESSOF)
1308 if (graph->points_to[lhsvar] == NULL)
1309 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1310 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1312 if (graph->pointed_by[rhsvar] == NULL)
1313 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1314 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1316 /* Implicitly, *x = y */
1317 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1319 /* All related variables are no longer direct nodes. */
1320 RESET_BIT (graph->direct_nodes, rhsvar);
1321 v = get_varinfo (rhsvar);
1322 if (!v->is_full_var)
1324 v = lookup_vi_for_tree (v->decl);
1327 RESET_BIT (graph->direct_nodes, v->id);
1332 bitmap_set_bit (graph->address_taken, rhsvar);
1334 else if (lhsvar > anything_id
1335 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1338 add_pred_graph_edge (graph, lhsvar, rhsvar);
1339 /* Implicitly, *x = *y */
1340 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1341 FIRST_REF_NODE + rhsvar);
1343 else if (lhs.offset != 0 || rhs.offset != 0)
1345 if (rhs.offset != 0)
1346 RESET_BIT (graph->direct_nodes, lhs.var);
1347 else if (lhs.offset != 0)
1348 RESET_BIT (graph->direct_nodes, rhs.var);
1353 /* Build the constraint graph, adding successor edges. */
1356 build_succ_graph (void)
1361 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1363 struct constraint_expr lhs;
1364 struct constraint_expr rhs;
1365 unsigned int lhsvar;
1366 unsigned int rhsvar;
1373 lhsvar = find (lhs.var);
1374 rhsvar = find (rhs.var);
1376 if (lhs.type == DEREF)
1378 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1379 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1381 else if (rhs.type == DEREF)
1383 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1384 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1386 else if (rhs.type == ADDRESSOF)
1389 gcc_assert (find (rhs.var) == rhs.var);
1390 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1392 else if (lhsvar > anything_id
1393 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1395 add_graph_edge (graph, lhsvar, rhsvar);
1399 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1400 receive pointers. */
1401 t = find (storedanything_id);
1402 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1404 if (!TEST_BIT (graph->direct_nodes, i)
1405 && get_varinfo (i)->may_have_pointers)
1406 add_graph_edge (graph, find (i), t);
1409 /* Everything stored to ANYTHING also potentially escapes. */
1410 add_graph_edge (graph, find (escaped_id), t);
1414 /* Changed variables on the last iteration. */
1415 static unsigned int changed_count;
1416 static sbitmap changed;
1418 /* Strongly Connected Component visitation info. */
1425 unsigned int *node_mapping;
1427 VEC(unsigned,heap) *scc_stack;
1431 /* Recursive routine to find strongly connected components in GRAPH.
1432 SI is the SCC info to store the information in, and N is the id of current
1433 graph node we are processing.
1435 This is Tarjan's strongly connected component finding algorithm, as
1436 modified by Nuutila to keep only non-root nodes on the stack.
1437 The algorithm can be found in "On finding the strongly connected
1438 connected components in a directed graph" by Esko Nuutila and Eljas
1439 Soisalon-Soininen, in Information Processing Letters volume 49,
1440 number 1, pages 9-14. */
1443 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1447 unsigned int my_dfs;
1449 SET_BIT (si->visited, n);
1450 si->dfs[n] = si->current_index ++;
1451 my_dfs = si->dfs[n];
1453 /* Visit all the successors. */
1454 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1458 if (i > LAST_REF_NODE)
1462 if (TEST_BIT (si->deleted, w))
1465 if (!TEST_BIT (si->visited, w))
1466 scc_visit (graph, si, w);
1468 unsigned int t = find (w);
1469 unsigned int nnode = find (n);
1470 gcc_assert (nnode == n);
1472 if (si->dfs[t] < si->dfs[nnode])
1473 si->dfs[n] = si->dfs[t];
1477 /* See if any components have been identified. */
1478 if (si->dfs[n] == my_dfs)
1480 if (VEC_length (unsigned, si->scc_stack) > 0
1481 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1483 bitmap scc = BITMAP_ALLOC (NULL);
1484 unsigned int lowest_node;
1487 bitmap_set_bit (scc, n);
1489 while (VEC_length (unsigned, si->scc_stack) != 0
1490 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1492 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1494 bitmap_set_bit (scc, w);
1497 lowest_node = bitmap_first_set_bit (scc);
1498 gcc_assert (lowest_node < FIRST_REF_NODE);
1500 /* Collapse the SCC nodes into a single node, and mark the
1502 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1504 if (i < FIRST_REF_NODE)
1506 if (unite (lowest_node, i))
1507 unify_nodes (graph, lowest_node, i, false);
1511 unite (lowest_node, i);
1512 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1516 SET_BIT (si->deleted, n);
1519 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1522 /* Unify node FROM into node TO, updating the changed count if
1523 necessary when UPDATE_CHANGED is true. */
1526 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1527 bool update_changed)
1530 gcc_assert (to != from && find (to) == to);
1531 if (dump_file && (dump_flags & TDF_DETAILS))
1532 fprintf (dump_file, "Unifying %s to %s\n",
1533 get_varinfo (from)->name,
1534 get_varinfo (to)->name);
1537 stats.unified_vars_dynamic++;
1539 stats.unified_vars_static++;
1541 merge_graph_nodes (graph, to, from);
1542 merge_node_constraints (graph, to, from);
1544 /* Mark TO as changed if FROM was changed. If TO was already marked
1545 as changed, decrease the changed count. */
1547 if (update_changed && TEST_BIT (changed, from))
1549 RESET_BIT (changed, from);
1550 if (!TEST_BIT (changed, to))
1551 SET_BIT (changed, to);
1554 gcc_assert (changed_count > 0);
1558 if (get_varinfo (from)->solution)
1560 /* If the solution changes because of the merging, we need to mark
1561 the variable as changed. */
1562 if (bitmap_ior_into (get_varinfo (to)->solution,
1563 get_varinfo (from)->solution))
1565 if (update_changed && !TEST_BIT (changed, to))
1567 SET_BIT (changed, to);
1572 BITMAP_FREE (get_varinfo (from)->solution);
1573 BITMAP_FREE (get_varinfo (from)->oldsolution);
1575 if (stats.iterations > 0)
1577 BITMAP_FREE (get_varinfo (to)->oldsolution);
1578 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1581 if (valid_graph_edge (graph, to, to))
1583 if (graph->succs[to])
1584 bitmap_clear_bit (graph->succs[to], to);
1588 /* Information needed to compute the topological ordering of a graph. */
1592 /* sbitmap of visited nodes. */
1594 /* Array that stores the topological order of the graph, *in
1596 VEC(unsigned,heap) *topo_order;
1600 /* Initialize and return a topological info structure. */
1602 static struct topo_info *
1603 init_topo_info (void)
1605 size_t size = graph->size;
1606 struct topo_info *ti = XNEW (struct topo_info);
1607 ti->visited = sbitmap_alloc (size);
1608 sbitmap_zero (ti->visited);
1609 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1614 /* Free the topological sort info pointed to by TI. */
1617 free_topo_info (struct topo_info *ti)
1619 sbitmap_free (ti->visited);
1620 VEC_free (unsigned, heap, ti->topo_order);
1624 /* Visit the graph in topological order, and store the order in the
1625 topo_info structure. */
1628 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1634 SET_BIT (ti->visited, n);
1636 if (graph->succs[n])
1637 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1639 if (!TEST_BIT (ti->visited, j))
1640 topo_visit (graph, ti, j);
1643 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1646 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1647 starting solution for y. */
1650 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1653 unsigned int lhs = c->lhs.var;
1655 bitmap sol = get_varinfo (lhs)->solution;
1658 HOST_WIDE_INT roffset = c->rhs.offset;
1660 /* Our IL does not allow this. */
1661 gcc_assert (c->lhs.offset == 0);
1663 /* If the solution of Y contains anything it is good enough to transfer
1665 if (bitmap_bit_p (delta, anything_id))
1667 flag |= bitmap_set_bit (sol, anything_id);
1671 /* If we do not know at with offset the rhs is dereferenced compute
1672 the reachability set of DELTA, conservatively assuming it is
1673 dereferenced at all valid offsets. */
1674 if (roffset == UNKNOWN_OFFSET)
1676 solution_set_expand (delta, delta);
1677 /* No further offset processing is necessary. */
1681 /* For each variable j in delta (Sol(y)), add
1682 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1683 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1685 varinfo_t v = get_varinfo (j);
1686 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1690 fieldoffset = v->offset;
1691 else if (roffset != 0)
1692 v = first_vi_for_offset (v, fieldoffset);
1693 /* If the access is outside of the variable we can ignore it. */
1701 /* Adding edges from the special vars is pointless.
1702 They don't have sets that can change. */
1703 if (get_varinfo (t)->is_special_var)
1704 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1705 /* Merging the solution from ESCAPED needlessly increases
1706 the set. Use ESCAPED as representative instead. */
1707 else if (v->id == escaped_id)
1708 flag |= bitmap_set_bit (sol, escaped_id);
1709 else if (v->may_have_pointers
1710 && add_graph_edge (graph, lhs, t))
1711 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1713 /* If the variable is not exactly at the requested offset
1714 we have to include the next one. */
1715 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1720 fieldoffset = v->offset;
1726 /* If the LHS solution changed, mark the var as changed. */
1729 get_varinfo (lhs)->solution = sol;
1730 if (!TEST_BIT (changed, lhs))
1732 SET_BIT (changed, lhs);
1738 /* Process a constraint C that represents *(x + off) = y using DELTA
1739 as the starting solution for x. */
1742 do_ds_constraint (constraint_t c, bitmap delta)
1744 unsigned int rhs = c->rhs.var;
1745 bitmap sol = get_varinfo (rhs)->solution;
1748 HOST_WIDE_INT loff = c->lhs.offset;
1749 bool escaped_p = false;
1751 /* Our IL does not allow this. */
1752 gcc_assert (c->rhs.offset == 0);
1754 /* If the solution of y contains ANYTHING simply use the ANYTHING
1755 solution. This avoids needlessly increasing the points-to sets. */
1756 if (bitmap_bit_p (sol, anything_id))
1757 sol = get_varinfo (find (anything_id))->solution;
1759 /* If the solution for x contains ANYTHING we have to merge the
1760 solution of y into all pointer variables which we do via
1762 if (bitmap_bit_p (delta, anything_id))
1764 unsigned t = find (storedanything_id);
1765 if (add_graph_edge (graph, t, rhs))
1767 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1769 if (!TEST_BIT (changed, t))
1771 SET_BIT (changed, t);
1779 /* If we do not know at with offset the rhs is dereferenced compute
1780 the reachability set of DELTA, conservatively assuming it is
1781 dereferenced at all valid offsets. */
1782 if (loff == UNKNOWN_OFFSET)
1784 solution_set_expand (delta, delta);
1788 /* For each member j of delta (Sol(x)), add an edge from y to j and
1789 union Sol(y) into Sol(j) */
1790 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1792 varinfo_t v = get_varinfo (j);
1794 HOST_WIDE_INT fieldoffset = v->offset + loff;
1797 fieldoffset = v->offset;
1799 v = first_vi_for_offset (v, fieldoffset);
1800 /* If the access is outside of the variable we can ignore it. */
1806 if (v->may_have_pointers)
1808 /* If v is a global variable then this is an escape point. */
1809 if (v->is_global_var
1812 t = find (escaped_id);
1813 if (add_graph_edge (graph, t, rhs)
1814 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1815 && !TEST_BIT (changed, t))
1817 SET_BIT (changed, t);
1820 /* Enough to let rhs escape once. */
1824 if (v->is_special_var)
1828 if (add_graph_edge (graph, t, rhs)
1829 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1830 && !TEST_BIT (changed, t))
1832 SET_BIT (changed, t);
1837 /* If the variable is not exactly at the requested offset
1838 we have to include the next one. */
1839 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1844 fieldoffset = v->offset;
1850 /* Handle a non-simple (simple meaning requires no iteration),
1851 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1854 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1856 if (c->lhs.type == DEREF)
1858 if (c->rhs.type == ADDRESSOF)
1865 do_ds_constraint (c, delta);
1868 else if (c->rhs.type == DEREF)
1871 if (!(get_varinfo (c->lhs.var)->is_special_var))
1872 do_sd_constraint (graph, c, delta);
1880 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1881 solution = get_varinfo (c->rhs.var)->solution;
1882 tmp = get_varinfo (c->lhs.var)->solution;
1884 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1888 get_varinfo (c->lhs.var)->solution = tmp;
1889 if (!TEST_BIT (changed, c->lhs.var))
1891 SET_BIT (changed, c->lhs.var);
1898 /* Initialize and return a new SCC info structure. */
1900 static struct scc_info *
1901 init_scc_info (size_t size)
1903 struct scc_info *si = XNEW (struct scc_info);
1906 si->current_index = 0;
1907 si->visited = sbitmap_alloc (size);
1908 sbitmap_zero (si->visited);
1909 si->deleted = sbitmap_alloc (size);
1910 sbitmap_zero (si->deleted);
1911 si->node_mapping = XNEWVEC (unsigned int, size);
1912 si->dfs = XCNEWVEC (unsigned int, size);
1914 for (i = 0; i < size; i++)
1915 si->node_mapping[i] = i;
1917 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1921 /* Free an SCC info structure pointed to by SI */
1924 free_scc_info (struct scc_info *si)
1926 sbitmap_free (si->visited);
1927 sbitmap_free (si->deleted);
1928 free (si->node_mapping);
1930 VEC_free (unsigned, heap, si->scc_stack);
1935 /* Find indirect cycles in GRAPH that occur, using strongly connected
1936 components, and note them in the indirect cycles map.
1938 This technique comes from Ben Hardekopf and Calvin Lin,
1939 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1940 Lines of Code", submitted to PLDI 2007. */
1943 find_indirect_cycles (constraint_graph_t graph)
1946 unsigned int size = graph->size;
1947 struct scc_info *si = init_scc_info (size);
1949 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1950 if (!TEST_BIT (si->visited, i) && find (i) == i)
1951 scc_visit (graph, si, i);
1956 /* Compute a topological ordering for GRAPH, and store the result in the
1957 topo_info structure TI. */
1960 compute_topo_order (constraint_graph_t graph,
1961 struct topo_info *ti)
1964 unsigned int size = graph->size;
1966 for (i = 0; i != size; ++i)
1967 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1968 topo_visit (graph, ti, i);
1971 /* Structure used to for hash value numbering of pointer equivalence
1974 typedef struct equiv_class_label
1977 unsigned int equivalence_class;
1979 } *equiv_class_label_t;
1980 typedef const struct equiv_class_label *const_equiv_class_label_t;
1982 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1984 static htab_t pointer_equiv_class_table;
1986 /* A hashtable for mapping a bitmap of labels->location equivalence
1988 static htab_t location_equiv_class_table;
1990 /* Hash function for a equiv_class_label_t */
1993 equiv_class_label_hash (const void *p)
1995 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1996 return ecl->hashcode;
1999 /* Equality function for two equiv_class_label_t's. */
2002 equiv_class_label_eq (const void *p1, const void *p2)
2004 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2005 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2006 return (eql1->hashcode == eql2->hashcode
2007 && bitmap_equal_p (eql1->labels, eql2->labels));
2010 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2014 equiv_class_lookup (htab_t table, bitmap labels)
2017 struct equiv_class_label ecl;
2019 ecl.labels = labels;
2020 ecl.hashcode = bitmap_hash (labels);
2022 slot = htab_find_slot_with_hash (table, &ecl,
2023 ecl.hashcode, NO_INSERT);
2027 return ((equiv_class_label_t) *slot)->equivalence_class;
2031 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2035 equiv_class_add (htab_t table, unsigned int equivalence_class,
2039 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2041 ecl->labels = labels;
2042 ecl->equivalence_class = equivalence_class;
2043 ecl->hashcode = bitmap_hash (labels);
2045 slot = htab_find_slot_with_hash (table, ecl,
2046 ecl->hashcode, INSERT);
2047 gcc_assert (!*slot);
2048 *slot = (void *) ecl;
2051 /* Perform offline variable substitution.
2053 This is a worst case quadratic time way of identifying variables
2054 that must have equivalent points-to sets, including those caused by
2055 static cycles, and single entry subgraphs, in the constraint graph.
2057 The technique is described in "Exploiting Pointer and Location
2058 Equivalence to Optimize Pointer Analysis. In the 14th International
2059 Static Analysis Symposium (SAS), August 2007." It is known as the
2060 "HU" algorithm, and is equivalent to value numbering the collapsed
2061 constraint graph including evaluating unions.
2063 The general method of finding equivalence classes is as follows:
2064 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2065 Initialize all non-REF nodes to be direct nodes.
2066 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2068 For each constraint containing the dereference, we also do the same
2071 We then compute SCC's in the graph and unify nodes in the same SCC,
2074 For each non-collapsed node x:
2075 Visit all unvisited explicit incoming edges.
2076 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2078 Lookup the equivalence class for pts(x).
2079 If we found one, equivalence_class(x) = found class.
2080 Otherwise, equivalence_class(x) = new class, and new_class is
2081 added to the lookup table.
2083 All direct nodes with the same equivalence class can be replaced
2084 with a single representative node.
2085 All unlabeled nodes (label == 0) are not pointers and all edges
2086 involving them can be eliminated.
2087 We perform these optimizations during rewrite_constraints
2089 In addition to pointer equivalence class finding, we also perform
2090 location equivalence class finding. This is the set of variables
2091 that always appear together in points-to sets. We use this to
2092 compress the size of the points-to sets. */
2094 /* Current maximum pointer equivalence class id. */
2095 static int pointer_equiv_class;
2097 /* Current maximum location equivalence class id. */
2098 static int location_equiv_class;
2100 /* Recursive routine to find strongly connected components in GRAPH,
2101 and label it's nodes with DFS numbers. */
2104 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2108 unsigned int my_dfs;
2110 gcc_assert (si->node_mapping[n] == n);
2111 SET_BIT (si->visited, n);
2112 si->dfs[n] = si->current_index ++;
2113 my_dfs = si->dfs[n];
2115 /* Visit all the successors. */
2116 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2118 unsigned int w = si->node_mapping[i];
2120 if (TEST_BIT (si->deleted, w))
2123 if (!TEST_BIT (si->visited, w))
2124 condense_visit (graph, si, w);
2126 unsigned int t = si->node_mapping[w];
2127 unsigned int nnode = si->node_mapping[n];
2128 gcc_assert (nnode == n);
2130 if (si->dfs[t] < si->dfs[nnode])
2131 si->dfs[n] = si->dfs[t];
2135 /* Visit all the implicit predecessors. */
2136 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2138 unsigned int w = si->node_mapping[i];
2140 if (TEST_BIT (si->deleted, w))
2143 if (!TEST_BIT (si->visited, w))
2144 condense_visit (graph, si, w);
2146 unsigned int t = si->node_mapping[w];
2147 unsigned int nnode = si->node_mapping[n];
2148 gcc_assert (nnode == n);
2150 if (si->dfs[t] < si->dfs[nnode])
2151 si->dfs[n] = si->dfs[t];
2155 /* See if any components have been identified. */
2156 if (si->dfs[n] == my_dfs)
2158 while (VEC_length (unsigned, si->scc_stack) != 0
2159 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2161 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2162 si->node_mapping[w] = n;
2164 if (!TEST_BIT (graph->direct_nodes, w))
2165 RESET_BIT (graph->direct_nodes, n);
2167 /* Unify our nodes. */
2168 if (graph->preds[w])
2170 if (!graph->preds[n])
2171 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2172 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2174 if (graph->implicit_preds[w])
2176 if (!graph->implicit_preds[n])
2177 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2178 bitmap_ior_into (graph->implicit_preds[n],
2179 graph->implicit_preds[w]);
2181 if (graph->points_to[w])
2183 if (!graph->points_to[n])
2184 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2185 bitmap_ior_into (graph->points_to[n],
2186 graph->points_to[w]);
2189 SET_BIT (si->deleted, n);
2192 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2195 /* Label pointer equivalences. */
2198 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2202 SET_BIT (si->visited, n);
2204 if (!graph->points_to[n])
2205 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2207 /* Label and union our incoming edges's points to sets. */
2208 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2210 unsigned int w = si->node_mapping[i];
2211 if (!TEST_BIT (si->visited, w))
2212 label_visit (graph, si, w);
2214 /* Skip unused edges */
2215 if (w == n || graph->pointer_label[w] == 0)
2218 if (graph->points_to[w])
2219 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2221 /* Indirect nodes get fresh variables. */
2222 if (!TEST_BIT (graph->direct_nodes, n))
2223 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2225 if (!bitmap_empty_p (graph->points_to[n]))
2227 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2228 graph->points_to[n]);
2231 label = pointer_equiv_class++;
2232 equiv_class_add (pointer_equiv_class_table,
2233 label, graph->points_to[n]);
2235 graph->pointer_label[n] = label;
2239 /* Perform offline variable substitution, discovering equivalence
2240 classes, and eliminating non-pointer variables. */
2242 static struct scc_info *
2243 perform_var_substitution (constraint_graph_t graph)
2246 unsigned int size = graph->size;
2247 struct scc_info *si = init_scc_info (size);
2249 bitmap_obstack_initialize (&iteration_obstack);
2250 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2251 equiv_class_label_eq, free);
2252 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2253 equiv_class_label_eq, free);
2254 pointer_equiv_class = 1;
2255 location_equiv_class = 1;
2257 /* Condense the nodes, which means to find SCC's, count incoming
2258 predecessors, and unite nodes in SCC's. */
2259 for (i = 0; i < FIRST_REF_NODE; i++)
2260 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2261 condense_visit (graph, si, si->node_mapping[i]);
2263 sbitmap_zero (si->visited);
2264 /* Actually the label the nodes for pointer equivalences */
2265 for (i = 0; i < FIRST_REF_NODE; i++)
2266 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2267 label_visit (graph, si, si->node_mapping[i]);
2269 /* Calculate location equivalence labels. */
2270 for (i = 0; i < FIRST_REF_NODE; i++)
2277 if (!graph->pointed_by[i])
2279 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2281 /* Translate the pointed-by mapping for pointer equivalence
2283 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2285 bitmap_set_bit (pointed_by,
2286 graph->pointer_label[si->node_mapping[j]]);
2288 /* The original pointed_by is now dead. */
2289 BITMAP_FREE (graph->pointed_by[i]);
2291 /* Look up the location equivalence label if one exists, or make
2293 label = equiv_class_lookup (location_equiv_class_table,
2297 label = location_equiv_class++;
2298 equiv_class_add (location_equiv_class_table,
2303 if (dump_file && (dump_flags & TDF_DETAILS))
2304 fprintf (dump_file, "Found location equivalence for node %s\n",
2305 get_varinfo (i)->name);
2306 BITMAP_FREE (pointed_by);
2308 graph->loc_label[i] = label;
2312 if (dump_file && (dump_flags & TDF_DETAILS))
2313 for (i = 0; i < FIRST_REF_NODE; i++)
2315 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2317 "Equivalence classes for %s node id %d:%s are pointer: %d"
2319 direct_node ? "Direct node" : "Indirect node", i,
2320 get_varinfo (i)->name,
2321 graph->pointer_label[si->node_mapping[i]],
2322 graph->loc_label[si->node_mapping[i]]);
2325 /* Quickly eliminate our non-pointer variables. */
2327 for (i = 0; i < FIRST_REF_NODE; i++)
2329 unsigned int node = si->node_mapping[i];
2331 if (graph->pointer_label[node] == 0)
2333 if (dump_file && (dump_flags & TDF_DETAILS))
2335 "%s is a non-pointer variable, eliminating edges.\n",
2336 get_varinfo (node)->name);
2337 stats.nonpointer_vars++;
2338 clear_edges_for_node (graph, node);
2345 /* Free information that was only necessary for variable
2349 free_var_substitution_info (struct scc_info *si)
2352 free (graph->pointer_label);
2353 free (graph->loc_label);
2354 free (graph->pointed_by);
2355 free (graph->points_to);
2356 free (graph->eq_rep);
2357 sbitmap_free (graph->direct_nodes);
2358 htab_delete (pointer_equiv_class_table);
2359 htab_delete (location_equiv_class_table);
2360 bitmap_obstack_release (&iteration_obstack);
2363 /* Return an existing node that is equivalent to NODE, which has
2364 equivalence class LABEL, if one exists. Return NODE otherwise. */
2367 find_equivalent_node (constraint_graph_t graph,
2368 unsigned int node, unsigned int label)
2370 /* If the address version of this variable is unused, we can
2371 substitute it for anything else with the same label.
2372 Otherwise, we know the pointers are equivalent, but not the
2373 locations, and we can unite them later. */
2375 if (!bitmap_bit_p (graph->address_taken, node))
2377 gcc_assert (label < graph->size);
2379 if (graph->eq_rep[label] != -1)
2381 /* Unify the two variables since we know they are equivalent. */
2382 if (unite (graph->eq_rep[label], node))
2383 unify_nodes (graph, graph->eq_rep[label], node, false);
2384 return graph->eq_rep[label];
2388 graph->eq_rep[label] = node;
2389 graph->pe_rep[label] = node;
2394 gcc_assert (label < graph->size);
2395 graph->pe[node] = label;
2396 if (graph->pe_rep[label] == -1)
2397 graph->pe_rep[label] = node;
2403 /* Unite pointer equivalent but not location equivalent nodes in
2404 GRAPH. This may only be performed once variable substitution is
2408 unite_pointer_equivalences (constraint_graph_t graph)
2412 /* Go through the pointer equivalences and unite them to their
2413 representative, if they aren't already. */
2414 for (i = 0; i < FIRST_REF_NODE; i++)
2416 unsigned int label = graph->pe[i];
2419 int label_rep = graph->pe_rep[label];
2421 if (label_rep == -1)
2424 label_rep = find (label_rep);
2425 if (label_rep >= 0 && unite (label_rep, find (i)))
2426 unify_nodes (graph, label_rep, i, false);
2431 /* Move complex constraints to the GRAPH nodes they belong to. */
2434 move_complex_constraints (constraint_graph_t graph)
2439 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2443 struct constraint_expr lhs = c->lhs;
2444 struct constraint_expr rhs = c->rhs;
2446 if (lhs.type == DEREF)
2448 insert_into_complex (graph, lhs.var, c);
2450 else if (rhs.type == DEREF)
2452 if (!(get_varinfo (lhs.var)->is_special_var))
2453 insert_into_complex (graph, rhs.var, c);
2455 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2456 && (lhs.offset != 0 || rhs.offset != 0))
2458 insert_into_complex (graph, rhs.var, c);
2465 /* Optimize and rewrite complex constraints while performing
2466 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2467 result of perform_variable_substitution. */
2470 rewrite_constraints (constraint_graph_t graph,
2471 struct scc_info *si)
2477 for (j = 0; j < graph->size; j++)
2478 gcc_assert (find (j) == j);
2480 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2482 struct constraint_expr lhs = c->lhs;
2483 struct constraint_expr rhs = c->rhs;
2484 unsigned int lhsvar = find (lhs.var);
2485 unsigned int rhsvar = find (rhs.var);
2486 unsigned int lhsnode, rhsnode;
2487 unsigned int lhslabel, rhslabel;
2489 lhsnode = si->node_mapping[lhsvar];
2490 rhsnode = si->node_mapping[rhsvar];
2491 lhslabel = graph->pointer_label[lhsnode];
2492 rhslabel = graph->pointer_label[rhsnode];
2494 /* See if it is really a non-pointer variable, and if so, ignore
2498 if (dump_file && (dump_flags & TDF_DETAILS))
2501 fprintf (dump_file, "%s is a non-pointer variable,"
2502 "ignoring constraint:",
2503 get_varinfo (lhs.var)->name);
2504 dump_constraint (dump_file, c);
2506 VEC_replace (constraint_t, constraints, i, NULL);
2512 if (dump_file && (dump_flags & TDF_DETAILS))
2515 fprintf (dump_file, "%s is a non-pointer variable,"
2516 "ignoring constraint:",
2517 get_varinfo (rhs.var)->name);
2518 dump_constraint (dump_file, c);
2520 VEC_replace (constraint_t, constraints, i, NULL);
2524 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2525 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2526 c->lhs.var = lhsvar;
2527 c->rhs.var = rhsvar;
2532 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2533 part of an SCC, false otherwise. */
2536 eliminate_indirect_cycles (unsigned int node)
2538 if (graph->indirect_cycles[node] != -1
2539 && !bitmap_empty_p (get_varinfo (node)->solution))
2542 VEC(unsigned,heap) *queue = NULL;
2544 unsigned int to = find (graph->indirect_cycles[node]);
2547 /* We can't touch the solution set and call unify_nodes
2548 at the same time, because unify_nodes is going to do
2549 bitmap unions into it. */
2551 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2553 if (find (i) == i && i != to)
2556 VEC_safe_push (unsigned, heap, queue, i);
2561 VEC_iterate (unsigned, queue, queuepos, i);
2564 unify_nodes (graph, to, i, true);
2566 VEC_free (unsigned, heap, queue);
2572 /* Solve the constraint graph GRAPH using our worklist solver.
2573 This is based on the PW* family of solvers from the "Efficient Field
2574 Sensitive Pointer Analysis for C" paper.
2575 It works by iterating over all the graph nodes, processing the complex
2576 constraints and propagating the copy constraints, until everything stops
2577 changed. This corresponds to steps 6-8 in the solving list given above. */
2580 solve_graph (constraint_graph_t graph)
2582 unsigned int size = graph->size;
2587 changed = sbitmap_alloc (size);
2588 sbitmap_zero (changed);
2590 /* Mark all initial non-collapsed nodes as changed. */
2591 for (i = 0; i < size; i++)
2593 varinfo_t ivi = get_varinfo (i);
2594 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2595 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2596 || VEC_length (constraint_t, graph->complex[i]) > 0))
2598 SET_BIT (changed, i);
2603 /* Allocate a bitmap to be used to store the changed bits. */
2604 pts = BITMAP_ALLOC (&pta_obstack);
2606 while (changed_count > 0)
2609 struct topo_info *ti = init_topo_info ();
2612 bitmap_obstack_initialize (&iteration_obstack);
2614 compute_topo_order (graph, ti);
2616 while (VEC_length (unsigned, ti->topo_order) != 0)
2619 i = VEC_pop (unsigned, ti->topo_order);
2621 /* If this variable is not a representative, skip it. */
2625 /* In certain indirect cycle cases, we may merge this
2626 variable to another. */
2627 if (eliminate_indirect_cycles (i) && find (i) != i)
2630 /* If the node has changed, we need to process the
2631 complex constraints and outgoing edges again. */
2632 if (TEST_BIT (changed, i))
2637 VEC(constraint_t,heap) *complex = graph->complex[i];
2638 bool solution_empty;
2640 RESET_BIT (changed, i);
2643 /* Compute the changed set of solution bits. */
2644 bitmap_and_compl (pts, get_varinfo (i)->solution,
2645 get_varinfo (i)->oldsolution);
2647 if (bitmap_empty_p (pts))
2650 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2652 solution = get_varinfo (i)->solution;
2653 solution_empty = bitmap_empty_p (solution);
2655 /* Process the complex constraints */
2656 for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++)
2658 /* XXX: This is going to unsort the constraints in
2659 some cases, which will occasionally add duplicate
2660 constraints during unification. This does not
2661 affect correctness. */
2662 c->lhs.var = find (c->lhs.var);
2663 c->rhs.var = find (c->rhs.var);
2665 /* The only complex constraint that can change our
2666 solution to non-empty, given an empty solution,
2667 is a constraint where the lhs side is receiving
2668 some set from elsewhere. */
2669 if (!solution_empty || c->lhs.type != DEREF)
2670 do_complex_constraint (graph, c, pts);
2673 solution_empty = bitmap_empty_p (solution);
2675 if (!solution_empty)
2678 unsigned eff_escaped_id = find (escaped_id);
2680 /* Propagate solution to all successors. */
2681 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2687 unsigned int to = find (j);
2688 tmp = get_varinfo (to)->solution;
2691 /* Don't try to propagate to ourselves. */
2695 /* If we propagate from ESCAPED use ESCAPED as
2697 if (i == eff_escaped_id)
2698 flag = bitmap_set_bit (tmp, escaped_id);
2700 flag = set_union_with_increment (tmp, pts, 0);
2704 get_varinfo (to)->solution = tmp;
2705 if (!TEST_BIT (changed, to))
2707 SET_BIT (changed, to);
2715 free_topo_info (ti);
2716 bitmap_obstack_release (&iteration_obstack);
2720 sbitmap_free (changed);
2721 bitmap_obstack_release (&oldpta_obstack);
2724 /* Map from trees to variable infos. */
2725 static struct pointer_map_t *vi_for_tree;
2728 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2731 insert_vi_for_tree (tree t, varinfo_t vi)
2733 void **slot = pointer_map_insert (vi_for_tree, t);
2735 gcc_assert (*slot == NULL);
2739 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2740 exist in the map, return NULL, otherwise, return the varinfo we found. */
2743 lookup_vi_for_tree (tree t)
2745 void **slot = pointer_map_contains (vi_for_tree, t);
2749 return (varinfo_t) *slot;
2752 /* Return a printable name for DECL */
2755 alias_get_name (tree decl)
2759 int num_printed = 0;
2761 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2762 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2764 res= get_name (decl);
2772 if (TREE_CODE (decl) == SSA_NAME)
2774 num_printed = asprintf (&temp, "%s_%u",
2775 alias_get_name (SSA_NAME_VAR (decl)),
2776 SSA_NAME_VERSION (decl));
2778 else if (DECL_P (decl))
2780 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2782 if (num_printed > 0)
2784 res = ggc_strdup (temp);
2790 /* Find the variable id for tree T in the map.
2791 If T doesn't exist in the map, create an entry for it and return it. */
2794 get_vi_for_tree (tree t)
2796 void **slot = pointer_map_contains (vi_for_tree, t);
2798 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2800 return (varinfo_t) *slot;
2803 /* Get a scalar constraint expression for a new temporary variable. */
2805 static struct constraint_expr
2806 new_scalar_tmp_constraint_exp (const char *name)
2808 struct constraint_expr tmp;
2811 vi = new_var_info (NULL_TREE, name);
2815 vi->is_full_var = 1;
2824 /* Get a constraint expression vector from an SSA_VAR_P node.
2825 If address_p is true, the result will be taken its address of. */
2828 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2830 struct constraint_expr cexpr;
2833 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2834 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2836 /* For parameters, get at the points-to set for the actual parm
2838 if (TREE_CODE (t) == SSA_NAME
2839 && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2840 && SSA_NAME_IS_DEFAULT_DEF (t))
2842 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2846 vi = get_vi_for_tree (t);
2848 cexpr.type = SCALAR;
2850 /* If we determine the result is "anything", and we know this is readonly,
2851 say it points to readonly memory instead. */
2852 if (cexpr.var == anything_id && TREE_READONLY (t))
2855 cexpr.type = ADDRESSOF;
2856 cexpr.var = readonly_id;
2859 /* If we are not taking the address of the constraint expr, add all
2860 sub-fiels of the variable as well. */
2862 && !vi->is_full_var)
2864 for (; vi; vi = vi->next)
2867 VEC_safe_push (ce_s, heap, *results, &cexpr);
2872 VEC_safe_push (ce_s, heap, *results, &cexpr);
2875 /* Process constraint T, performing various simplifications and then
2876 adding it to our list of overall constraints. */
2879 process_constraint (constraint_t t)
2881 struct constraint_expr rhs = t->rhs;
2882 struct constraint_expr lhs = t->lhs;
2884 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2885 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2887 /* If we didn't get any useful constraint from the lhs we get
2888 &ANYTHING as fallback from get_constraint_for. Deal with
2889 it here by turning it into *ANYTHING. */
2890 if (lhs.type == ADDRESSOF
2891 && lhs.var == anything_id)
2894 /* ADDRESSOF on the lhs is invalid. */
2895 gcc_assert (lhs.type != ADDRESSOF);
2897 /* We shouldn't add constraints from things that cannot have pointers.
2898 It's not completely trivial to avoid in the callers, so do it here. */
2899 if (rhs.type != ADDRESSOF
2900 && !get_varinfo (rhs.var)->may_have_pointers)
2903 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2904 if (!get_varinfo (lhs.var)->may_have_pointers)
2907 /* This can happen in our IR with things like n->a = *p */
2908 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2910 /* Split into tmp = *rhs, *lhs = tmp */
2911 struct constraint_expr tmplhs;
2912 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2913 process_constraint (new_constraint (tmplhs, rhs));
2914 process_constraint (new_constraint (lhs, tmplhs));
2916 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2918 /* Split into tmp = &rhs, *lhs = tmp */
2919 struct constraint_expr tmplhs;
2920 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2921 process_constraint (new_constraint (tmplhs, rhs));
2922 process_constraint (new_constraint (lhs, tmplhs));
2926 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2927 VEC_safe_push (constraint_t, heap, constraints, t);
2931 /* Return true if T is a type that could contain pointers. */
2934 type_could_have_pointers (tree type)
2936 if (POINTER_TYPE_P (type))
2939 if (TREE_CODE (type) == ARRAY_TYPE)
2940 return type_could_have_pointers (TREE_TYPE (type));
2942 /* A function or method can consume pointers.
2943 ??? We could be more precise here. */
2944 if (TREE_CODE (type) == FUNCTION_TYPE
2945 || TREE_CODE (type) == METHOD_TYPE)
2948 return AGGREGATE_TYPE_P (type);
2951 /* Return true if T is a variable of a type that could contain
2955 could_have_pointers (tree t)
2957 return (((TREE_CODE (t) == VAR_DECL
2958 || TREE_CODE (t) == PARM_DECL
2959 || TREE_CODE (t) == RESULT_DECL)
2960 && (TREE_PUBLIC (t) || DECL_EXTERNAL (t) || TREE_ADDRESSABLE (t)))
2961 || type_could_have_pointers (TREE_TYPE (t)));
2964 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2967 static HOST_WIDE_INT
2968 bitpos_of_field (const tree fdecl)
2971 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2972 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2975 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2976 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2980 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2981 resulting constraint expressions in *RESULTS. */
2984 get_constraint_for_ptr_offset (tree ptr, tree offset,
2985 VEC (ce_s, heap) **results)
2987 struct constraint_expr c;
2989 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2991 /* If we do not do field-sensitive PTA adding offsets to pointers
2992 does not change the points-to solution. */
2993 if (!use_field_sensitive)
2995 get_constraint_for (ptr, results);
2999 /* If the offset is not a non-negative integer constant that fits
3000 in a HOST_WIDE_INT, we have to fall back to a conservative
3001 solution which includes all sub-fields of all pointed-to
3002 variables of ptr. */
3003 if (offset == NULL_TREE
3004 || !host_integerp (offset, 0))
3005 rhsoffset = UNKNOWN_OFFSET;
3008 /* Make sure the bit-offset also fits. */
3009 rhsunitoffset = TREE_INT_CST_LOW (offset);
3010 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
3011 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
3012 rhsoffset = UNKNOWN_OFFSET;
3015 get_constraint_for (ptr, results);
3019 /* As we are eventually appending to the solution do not use
3020 VEC_iterate here. */
3021 n = VEC_length (ce_s, *results);
3022 for (j = 0; j < n; j++)
3025 c = *VEC_index (ce_s, *results, j);
3026 curr = get_varinfo (c.var);
3028 if (c.type == ADDRESSOF
3029 /* If this varinfo represents a full variable just use it. */
3030 && curr->is_full_var)
3032 else if (c.type == ADDRESSOF
3033 /* If we do not know the offset add all subfields. */
3034 && rhsoffset == UNKNOWN_OFFSET)
3036 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3039 struct constraint_expr c2;
3041 c2.type = ADDRESSOF;
3043 if (c2.var != c.var)
3044 VEC_safe_push (ce_s, heap, *results, &c2);
3049 else if (c.type == ADDRESSOF)
3052 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3054 /* Search the sub-field which overlaps with the
3055 pointed-to offset. If the result is outside of the variable
3056 we have to provide a conservative result, as the variable is
3057 still reachable from the resulting pointer (even though it
3058 technically cannot point to anything). The last and first
3059 sub-fields are such conservative results.
3060 ??? If we always had a sub-field for &object + 1 then
3061 we could represent this in a more precise way. */
3063 && curr->offset < offset)
3065 temp = first_or_preceding_vi_for_offset (curr, offset);
3067 /* If the found variable is not exactly at the pointed to
3068 result, we have to include the next variable in the
3069 solution as well. Otherwise two increments by offset / 2
3070 do not result in the same or a conservative superset
3072 if (temp->offset != offset
3073 && temp->next != NULL)
3075 struct constraint_expr c2;
3076 c2.var = temp->next->id;
3077 c2.type = ADDRESSOF;
3079 VEC_safe_push (ce_s, heap, *results, &c2);
3085 c.offset = rhsoffset;
3087 VEC_replace (ce_s, *results, j, &c);
3092 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3093 If address_p is true the result will be taken its address of. */
3096 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3100 HOST_WIDE_INT bitsize = -1;
3101 HOST_WIDE_INT bitmaxsize = -1;
3102 HOST_WIDE_INT bitpos;
3104 struct constraint_expr *result;
3106 /* Some people like to do cute things like take the address of
3109 while (handled_component_p (forzero)
3110 || INDIRECT_REF_P (forzero)
3111 || TREE_CODE (forzero) == MEM_REF)
3112 forzero = TREE_OPERAND (forzero, 0);
3114 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3116 struct constraint_expr temp;
3119 temp.var = integer_id;
3121 VEC_safe_push (ce_s, heap, *results, &temp);
3125 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3127 /* Pretend to take the address of the base, we'll take care of
3128 adding the required subset of sub-fields below. */
3129 get_constraint_for_1 (t, results, true);
3130 gcc_assert (VEC_length (ce_s, *results) == 1);
3131 result = VEC_last (ce_s, *results);
3133 if (result->type == SCALAR
3134 && get_varinfo (result->var)->is_full_var)
3135 /* For single-field vars do not bother about the offset. */
3137 else if (result->type == SCALAR)
3139 /* In languages like C, you can access one past the end of an
3140 array. You aren't allowed to dereference it, so we can
3141 ignore this constraint. When we handle pointer subtraction,
3142 we may have to do something cute here. */
3144 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3147 /* It's also not true that the constraint will actually start at the
3148 right offset, it may start in some padding. We only care about
3149 setting the constraint to the first actual field it touches, so
3151 struct constraint_expr cexpr = *result;
3153 VEC_pop (ce_s, *results);
3155 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3157 if (ranges_overlap_p (curr->offset, curr->size,
3158 bitpos, bitmaxsize))
3160 cexpr.var = curr->id;
3161 VEC_safe_push (ce_s, heap, *results, &cexpr);
3166 /* If we are going to take the address of this field then
3167 to be able to compute reachability correctly add at least
3168 the last field of the variable. */
3170 && VEC_length (ce_s, *results) == 0)
3172 curr = get_varinfo (cexpr.var);
3173 while (curr->next != NULL)
3175 cexpr.var = curr->id;
3176 VEC_safe_push (ce_s, heap, *results, &cexpr);
3179 /* Assert that we found *some* field there. The user couldn't be
3180 accessing *only* padding. */
3181 /* Still the user could access one past the end of an array
3182 embedded in a struct resulting in accessing *only* padding. */
3183 gcc_assert (VEC_length (ce_s, *results) >= 1
3184 || ref_contains_array_ref (orig_t));
3186 else if (bitmaxsize == 0)
3188 if (dump_file && (dump_flags & TDF_DETAILS))
3189 fprintf (dump_file, "Access to zero-sized part of variable,"
3193 if (dump_file && (dump_flags & TDF_DETAILS))
3194 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3196 else if (result->type == DEREF)
3198 /* If we do not know exactly where the access goes say so. Note
3199 that only for non-structure accesses we know that we access
3200 at most one subfiled of any variable. */
3202 || bitsize != bitmaxsize
3203 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3204 result->offset = UNKNOWN_OFFSET;
3206 result->offset = bitpos;
3208 else if (result->type == ADDRESSOF)
3210 /* We can end up here for component references on a
3211 VIEW_CONVERT_EXPR <>(&foobar). */
3212 result->type = SCALAR;
3213 result->var = anything_id;
3221 /* Dereference the constraint expression CONS, and return the result.
3222 DEREF (ADDRESSOF) = SCALAR
3223 DEREF (SCALAR) = DEREF
3224 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3225 This is needed so that we can handle dereferencing DEREF constraints. */
3228 do_deref (VEC (ce_s, heap) **constraints)
3230 struct constraint_expr *c;
3233 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3235 if (c->type == SCALAR)
3237 else if (c->type == ADDRESSOF)
3239 else if (c->type == DEREF)
3241 struct constraint_expr tmplhs;
3242 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3243 process_constraint (new_constraint (tmplhs, *c));
3244 c->var = tmplhs.var;
3251 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3253 /* Given a tree T, return the constraint expression for taking the
3257 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3259 struct constraint_expr *c;
3262 get_constraint_for_1 (t, results, true);
3264 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3266 if (c->type == DEREF)
3269 c->type = ADDRESSOF;
3273 /* Given a tree T, return the constraint expression for it. */
3276 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3278 struct constraint_expr temp;
3280 /* x = integer is all glommed to a single variable, which doesn't
3281 point to anything by itself. That is, of course, unless it is an
3282 integer constant being treated as a pointer, in which case, we
3283 will return that this is really the addressof anything. This
3284 happens below, since it will fall into the default case. The only
3285 case we know something about an integer treated like a pointer is
3286 when it is the NULL pointer, and then we just say it points to
3289 Do not do that if -fno-delete-null-pointer-checks though, because
3290 in that case *NULL does not fail, so it _should_ alias *anything.
3291 It is not worth adding a new option or renaming the existing one,
3292 since this case is relatively obscure. */
3293 if ((TREE_CODE (t) == INTEGER_CST
3294 && integer_zerop (t))
3295 /* The only valid CONSTRUCTORs in gimple with pointer typed
3296 elements are zero-initializer. But in IPA mode we also
3297 process global initializers, so verify at least. */
3298 || (TREE_CODE (t) == CONSTRUCTOR
3299 && CONSTRUCTOR_NELTS (t) == 0))
3301 if (flag_delete_null_pointer_checks)
3302 temp.var = nothing_id;
3304 temp.var = anything_id;
3305 temp.type = ADDRESSOF;
3307 VEC_safe_push (ce_s, heap, *results, &temp);
3311 /* String constants are read-only. */
3312 if (TREE_CODE (t) == STRING_CST)
3314 temp.var = readonly_id;
3317 VEC_safe_push (ce_s, heap, *results, &temp);
3321 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3323 case tcc_expression:
3325 switch (TREE_CODE (t))
3328 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3336 switch (TREE_CODE (t))
3340 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
3341 TREE_OPERAND (t, 1), results);
3346 case ARRAY_RANGE_REF:
3348 get_constraint_for_component_ref (t, results, address_p);
3350 case VIEW_CONVERT_EXPR:
3351 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3353 /* We are missing handling for TARGET_MEM_REF here. */
3358 case tcc_exceptional:
3360 switch (TREE_CODE (t))
3364 get_constraint_for_ssa_var (t, results, address_p);
3371 VEC (ce_s, heap) *tmp = NULL;
3372 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3374 struct constraint_expr *rhsp;
3376 get_constraint_for_1 (val, &tmp, address_p);
3377 for (j = 0; VEC_iterate (ce_s, tmp, j, rhsp); ++j)
3378 VEC_safe_push (ce_s, heap, *results, rhsp);
3379 VEC_truncate (ce_s, tmp, 0);
3381 VEC_free (ce_s, heap, tmp);
3382 /* We do not know whether the constructor was complete,
3383 so technically we have to add &NOTHING or &ANYTHING
3384 like we do for an empty constructor as well. */
3391 case tcc_declaration:
3393 get_constraint_for_ssa_var (t, results, address_p);
3399 /* The default fallback is a constraint from anything. */
3400 temp.type = ADDRESSOF;
3401 temp.var = anything_id;
3403 VEC_safe_push (ce_s, heap, *results, &temp);
3406 /* Given a gimple tree T, return the constraint expression vector for it. */
3409 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3411 gcc_assert (VEC_length (ce_s, *results) == 0);
3413 get_constraint_for_1 (t, results, false);
3417 /* Efficiently generates constraints from all entries in *RHSC to all
3418 entries in *LHSC. */
3421 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3423 struct constraint_expr *lhsp, *rhsp;
3426 if (VEC_length (ce_s, lhsc) <= 1
3427 || VEC_length (ce_s, rhsc) <= 1)
3429 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3430 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3431 process_constraint (new_constraint (*lhsp, *rhsp));
3435 struct constraint_expr tmp;
3436 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3437 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3438 process_constraint (new_constraint (tmp, *rhsp));
3439 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3440 process_constraint (new_constraint (*lhsp, tmp));
3444 /* Handle aggregate copies by expanding into copies of the respective
3445 fields of the structures. */
3448 do_structure_copy (tree lhsop, tree rhsop)
3450 struct constraint_expr *lhsp, *rhsp;
3451 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3454 get_constraint_for (lhsop, &lhsc);
3455 get_constraint_for (rhsop, &rhsc);
3456 lhsp = VEC_index (ce_s, lhsc, 0);
3457 rhsp = VEC_index (ce_s, rhsc, 0);
3458 if (lhsp->type == DEREF
3459 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3460 || rhsp->type == DEREF)
3462 if (lhsp->type == DEREF)
3464 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3465 lhsp->offset = UNKNOWN_OFFSET;
3467 if (rhsp->type == DEREF)
3469 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3470 rhsp->offset = UNKNOWN_OFFSET;
3472 process_all_all_constraints (lhsc, rhsc);
3474 else if (lhsp->type == SCALAR
3475 && (rhsp->type == SCALAR
3476 || rhsp->type == ADDRESSOF))
3478 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3479 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3481 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3482 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3483 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3485 varinfo_t lhsv, rhsv;
3486 rhsp = VEC_index (ce_s, rhsc, k);
3487 lhsv = get_varinfo (lhsp->var);
3488 rhsv = get_varinfo (rhsp->var);
3489 if (lhsv->may_have_pointers
3490 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3491 rhsv->offset + lhsoffset, rhsv->size))
3492 process_constraint (new_constraint (*lhsp, *rhsp));
3493 if (lhsv->offset + rhsoffset + lhsv->size
3494 > rhsv->offset + lhsoffset + rhsv->size)
3497 if (k >= VEC_length (ce_s, rhsc))
3507 VEC_free (ce_s, heap, lhsc);
3508 VEC_free (ce_s, heap, rhsc);
3511 /* Create a constraint ID = OP. */
3514 make_constraint_to (unsigned id, tree op)
3516 VEC(ce_s, heap) *rhsc = NULL;
3517 struct constraint_expr *c;
3518 struct constraint_expr includes;
3522 includes.offset = 0;
3523 includes.type = SCALAR;
3525 get_constraint_for (op, &rhsc);
3526 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3527 process_constraint (new_constraint (includes, *c));
3528 VEC_free (ce_s, heap, rhsc);
3531 /* Create a constraint ID = &FROM. */
3534 make_constraint_from (varinfo_t vi, int from)
3536 struct constraint_expr lhs, rhs;
3544 rhs.type = ADDRESSOF;
3545 process_constraint (new_constraint (lhs, rhs));
3548 /* Create a constraint ID = FROM. */
3551 make_copy_constraint (varinfo_t vi, int from)
3553 struct constraint_expr lhs, rhs;
3562 process_constraint (new_constraint (lhs, rhs));
3565 /* Make constraints necessary to make OP escape. */
3568 make_escape_constraint (tree op)
3570 make_constraint_to (escaped_id, op);
3573 /* Add constraints to that the solution of VI is transitively closed. */
3576 make_transitive_closure_constraints (varinfo_t vi)
3578 struct constraint_expr lhs, rhs;
3587 process_constraint (new_constraint (lhs, rhs));
3589 /* VAR = VAR + UNKNOWN; */
3595 rhs.offset = UNKNOWN_OFFSET;
3596 process_constraint (new_constraint (lhs, rhs));
3599 /* Create a new artificial heap variable with NAME.
3600 Return the created variable. */
3603 make_heapvar_for (varinfo_t lhs, const char *name)
3606 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3608 if (heapvar == NULL_TREE)
3611 heapvar = create_tmp_var_raw (ptr_type_node, name);
3612 DECL_EXTERNAL (heapvar) = 1;
3614 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3616 ann = get_var_ann (heapvar);
3617 ann->is_heapvar = 1;
3620 /* For global vars we need to add a heapvar to the list of referenced
3621 vars of a different function than it was created for originally. */
3622 if (cfun && gimple_referenced_vars (cfun))
3623 add_referenced_var (heapvar);
3625 vi = new_var_info (heapvar, name);
3626 vi->is_artificial_var = true;
3627 vi->is_heap_var = true;
3628 vi->is_unknown_size_var = true;
3632 vi->is_full_var = true;
3633 insert_vi_for_tree (heapvar, vi);
3638 /* Create a new artificial heap variable with NAME and make a
3639 constraint from it to LHS. Return the created variable. */
3642 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3644 varinfo_t vi = make_heapvar_for (lhs, name);
3645 make_constraint_from (lhs, vi->id);
3650 /* Create a new artificial heap variable with NAME and make a
3651 constraint from it to LHS. Set flags according to a tag used
3652 for tracking restrict pointers. */
3655 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3658 vi = make_constraint_from_heapvar (lhs, name);
3659 vi->is_restrict_var = 1;
3660 vi->is_global_var = 0;
3661 vi->is_special_var = 1;
3662 vi->may_have_pointers = 0;
3665 /* In IPA mode there are varinfos for different aspects of reach
3666 function designator. One for the points-to set of the return
3667 value, one for the variables that are clobbered by the function,
3668 one for its uses and one for each parameter (including a single
3669 glob for remaining variadic arguments). */
3671 enum { fi_clobbers = 1, fi_uses = 2,
3672 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3674 /* Get a constraint for the requested part of a function designator FI
3675 when operating in IPA mode. */
3677 static struct constraint_expr
3678 get_function_part_constraint (varinfo_t fi, unsigned part)
3680 struct constraint_expr c;
3682 gcc_assert (in_ipa_mode);
3684 if (fi->id == anything_id)
3686 /* ??? We probably should have a ANYFN special variable. */
3687 c.var = anything_id;
3691 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3693 varinfo_t ai = first_vi_for_offset (fi, part);
3697 c.var = anything_id;
3711 /* For non-IPA mode, generate constraints necessary for a call on the
3715 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3717 struct constraint_expr rhsc;
3719 bool returns_uses = false;
3721 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3723 tree arg = gimple_call_arg (stmt, i);
3724 int flags = gimple_call_arg_flags (stmt, i);
3726 /* If the argument is not used or it does not contain pointers
3727 we can ignore it. */
3728 if ((flags & EAF_UNUSED)
3729 || !could_have_pointers (arg))
3732 /* As we compute ESCAPED context-insensitive we do not gain
3733 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3734 set. The argument would still get clobbered through the
3736 ??? We might get away with less (and more precise) constraints
3737 if using a temporary for transitively closing things. */
3738 if ((flags & EAF_NOCLOBBER)
3739 && (flags & EAF_NOESCAPE))
3741 varinfo_t uses = get_call_use_vi (stmt);
3742 if (!(flags & EAF_DIRECT))
3743 make_transitive_closure_constraints (uses);
3744 make_constraint_to (uses->id, arg);
3745 returns_uses = true;
3747 else if (flags & EAF_NOESCAPE)
3749 varinfo_t uses = get_call_use_vi (stmt);
3750 varinfo_t clobbers = get_call_clobber_vi (stmt);
3751 if (!(flags & EAF_DIRECT))
3753 make_transitive_closure_constraints (uses);
3754 make_transitive_closure_constraints (clobbers);
3756 make_constraint_to (uses->id, arg);
3757 make_constraint_to (clobbers->id, arg);
3758 returns_uses = true;
3761 make_escape_constraint (arg);
3764 /* If we added to the calls uses solution make sure we account for
3765 pointers to it to be returned. */
3768 rhsc.var = get_call_use_vi (stmt)->id;
3771 VEC_safe_push (ce_s, heap, *results, &rhsc);
3774 /* The static chain escapes as well. */
3775 if (gimple_call_chain (stmt))
3776 make_escape_constraint (gimple_call_chain (stmt));
3778 /* And if we applied NRV the address of the return slot escapes as well. */
3779 if (gimple_call_return_slot_opt_p (stmt)
3780 && gimple_call_lhs (stmt) != NULL_TREE
3781 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3783 VEC(ce_s, heap) *tmpc = NULL;
3784 struct constraint_expr lhsc, *c;
3785 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3786 lhsc.var = escaped_id;
3789 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3790 process_constraint (new_constraint (lhsc, *c));
3791 VEC_free(ce_s, heap, tmpc);
3794 /* Regular functions return nonlocal memory. */
3795 rhsc.var = nonlocal_id;
3798 VEC_safe_push (ce_s, heap, *results, &rhsc);
3801 /* For non-IPA mode, generate constraints necessary for a call
3802 that returns a pointer and assigns it to LHS. This simply makes
3803 the LHS point to global and escaped variables. */
3806 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3809 VEC(ce_s, heap) *lhsc = NULL;
3811 get_constraint_for (lhs, &lhsc);
3812 /* If the store is to a global decl make sure to
3813 add proper escape constraints. */
3814 lhs = get_base_address (lhs);
3817 && is_global_var (lhs))
3819 struct constraint_expr tmpc;
3820 tmpc.var = escaped_id;
3823 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3826 /* If the call returns an argument unmodified override the rhs
3828 flags = gimple_call_return_flags (stmt);
3829 if (flags & ERF_RETURNS_ARG
3830 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3834 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3835 get_constraint_for (arg, &rhsc);
3836 process_all_all_constraints (lhsc, rhsc);
3837 VEC_free (ce_s, heap, rhsc);
3839 else if (flags & ERF_NOALIAS)
3842 struct constraint_expr tmpc;
3844 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3845 /* We delay marking allocated storage global until we know if
3847 DECL_EXTERNAL (vi->decl) = 0;
3848 vi->is_global_var = 0;
3849 /* If this is not a real malloc call assume the memory was
3850 initialized and thus may point to global memory. All
3851 builtin functions with the malloc attribute behave in a sane way. */
3853 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3854 make_constraint_from (vi, nonlocal_id);
3857 tmpc.type = ADDRESSOF;
3858 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3861 process_all_all_constraints (lhsc, rhsc);
3863 VEC_free (ce_s, heap, lhsc);
3866 /* For non-IPA mode, generate constraints necessary for a call of a
3867 const function that returns a pointer in the statement STMT. */
3870 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3872 struct constraint_expr rhsc;
3875 /* Treat nested const functions the same as pure functions as far
3876 as the static chain is concerned. */
3877 if (gimple_call_chain (stmt))
3879 varinfo_t uses = get_call_use_vi (stmt);
3880 make_transitive_closure_constraints (uses);
3881 make_constraint_to (uses->id, gimple_call_chain (stmt));
3882 rhsc.var = uses->id;
3885 VEC_safe_push (ce_s, heap, *results, &rhsc);
3888 /* May return arguments. */
3889 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3891 tree arg = gimple_call_arg (stmt, k);
3893 if (could_have_pointers (arg))
3895 VEC(ce_s, heap) *argc = NULL;
3897 struct constraint_expr *argp;
3898 get_constraint_for (arg, &argc);
3899 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3900 VEC_safe_push (ce_s, heap, *results, argp);
3901 VEC_free(ce_s, heap, argc);
3905 /* May return addresses of globals. */
3906 rhsc.var = nonlocal_id;
3908 rhsc.type = ADDRESSOF;
3909 VEC_safe_push (ce_s, heap, *results, &rhsc);
3912 /* For non-IPA mode, generate constraints necessary for a call to a
3913 pure function in statement STMT. */
3916 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3918 struct constraint_expr rhsc;
3920 varinfo_t uses = NULL;
3922 /* Memory reached from pointer arguments is call-used. */
3923 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3925 tree arg = gimple_call_arg (stmt, i);
3927 if (could_have_pointers (arg))
3931 uses = get_call_use_vi (stmt);
3932 make_transitive_closure_constraints (uses);
3934 make_constraint_to (uses->id, arg);
3938 /* The static chain is used as well. */
3939 if (gimple_call_chain (stmt))
3943 uses = get_call_use_vi (stmt);
3944 make_transitive_closure_constraints (uses);
3946 make_constraint_to (uses->id, gimple_call_chain (stmt));
3949 /* Pure functions may return call-used and nonlocal memory. */
3952 rhsc.var = uses->id;
3955 VEC_safe_push (ce_s, heap, *results, &rhsc);
3957 rhsc.var = nonlocal_id;
3960 VEC_safe_push (ce_s, heap, *results, &rhsc);
3964 /* Return the varinfo for the callee of CALL. */
3967 get_fi_for_callee (gimple call)
3971 /* If we can directly resolve the function being called, do so.
3972 Otherwise, it must be some sort of indirect expression that
3973 we should still be able to handle. */
3974 decl = gimple_call_fndecl (call);
3976 return get_vi_for_tree (decl);
3978 decl = gimple_call_fn (call);
3979 /* The function can be either an SSA name pointer or,
3980 worse, an OBJ_TYPE_REF. In this case we have no
3981 clue and should be getting ANYFN (well, ANYTHING for now). */
3982 if (TREE_CODE (decl) == SSA_NAME)
3984 if (TREE_CODE (decl) == SSA_NAME
3985 && TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3986 && SSA_NAME_IS_DEFAULT_DEF (decl))
3987 decl = SSA_NAME_VAR (decl);
3988 return get_vi_for_tree (decl);
3990 else if (TREE_CODE (decl) == INTEGER_CST
3991 || TREE_CODE (decl) == OBJ_TYPE_REF)
3992 return get_varinfo (anything_id);
3997 /* Walk statement T setting up aliasing constraints according to the
3998 references found in T. This function is the main part of the
3999 constraint builder. AI points to auxiliary alias information used
4000 when building alias sets and computing alias grouping heuristics. */
4003 find_func_aliases (gimple origt)
4006 VEC(ce_s, heap) *lhsc = NULL;
4007 VEC(ce_s, heap) *rhsc = NULL;
4008 struct constraint_expr *c;
4011 /* Now build constraints expressions. */
4012 if (gimple_code (t) == GIMPLE_PHI)
4014 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4016 /* Only care about pointers and structures containing
4018 if (could_have_pointers (gimple_phi_result (t)))
4023 /* For a phi node, assign all the arguments to
4025 get_constraint_for (gimple_phi_result (t), &lhsc);
4026 for (i = 0; i < gimple_phi_num_args (t); i++)
4028 tree strippedrhs = PHI_ARG_DEF (t, i);
4030 STRIP_NOPS (strippedrhs);
4031 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
4033 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
4035 struct constraint_expr *c2;
4036 while (VEC_length (ce_s, rhsc) > 0)
4038 c2 = VEC_last (ce_s, rhsc);
4039 process_constraint (new_constraint (*c, *c2));
4040 VEC_pop (ce_s, rhsc);
4046 /* In IPA mode, we need to generate constraints to pass call
4047 arguments through their calls. There are two cases,
4048 either a GIMPLE_CALL returning a value, or just a plain
4049 GIMPLE_CALL when we are not.
4051 In non-ipa mode, we need to generate constraints for each
4052 pointer passed by address. */
4053 else if (is_gimple_call (t))
4055 tree fndecl = gimple_call_fndecl (t);
4056 if (fndecl != NULL_TREE
4057 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4058 /* ??? All builtins that are handled here need to be handled
4059 in the alias-oracle query functions explicitly! */
4060 switch (DECL_FUNCTION_CODE (fndecl))
4062 /* All the following functions return a pointer to the same object
4063 as their first argument points to. The functions do not add
4064 to the ESCAPED solution. The functions make the first argument
4065 pointed to memory point to what the second argument pointed to
4066 memory points to. */
4067 case BUILT_IN_STRCPY:
4068 case BUILT_IN_STRNCPY:
4069 case BUILT_IN_BCOPY:
4070 case BUILT_IN_MEMCPY:
4071 case BUILT_IN_MEMMOVE:
4072 case BUILT_IN_MEMPCPY:
4073 case BUILT_IN_STPCPY:
4074 case BUILT_IN_STPNCPY:
4075 case BUILT_IN_STRCAT:
4076 case BUILT_IN_STRNCAT:
4078 tree res = gimple_call_lhs (t);
4079 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4080 == BUILT_IN_BCOPY ? 1 : 0));
4081 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4082 == BUILT_IN_BCOPY ? 0 : 1));
4083 if (res != NULL_TREE)
4085 get_constraint_for (res, &lhsc);
4086 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4087 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4088 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4089 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4091 get_constraint_for (dest, &rhsc);
4092 process_all_all_constraints (lhsc, rhsc);
4093 VEC_free (ce_s, heap, lhsc);
4094 VEC_free (ce_s, heap, rhsc);
4096 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4097 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4100 process_all_all_constraints (lhsc, rhsc);
4101 VEC_free (ce_s, heap, lhsc);
4102 VEC_free (ce_s, heap, rhsc);
4105 case BUILT_IN_MEMSET:
4107 tree res = gimple_call_lhs (t);
4108 tree dest = gimple_call_arg (t, 0);
4111 struct constraint_expr ac;
4112 if (res != NULL_TREE)
4114 get_constraint_for (res, &lhsc);
4115 get_constraint_for (dest, &rhsc);
4116 process_all_all_constraints (lhsc, rhsc);
4117 VEC_free (ce_s, heap, lhsc);
4118 VEC_free (ce_s, heap, rhsc);
4120 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4122 if (flag_delete_null_pointer_checks
4123 && integer_zerop (gimple_call_arg (t, 1)))
4125 ac.type = ADDRESSOF;
4126 ac.var = nothing_id;
4131 ac.var = integer_id;
4134 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4135 process_constraint (new_constraint (*lhsp, ac));
4136 VEC_free (ce_s, heap, lhsc);
4139 /* All the following functions do not return pointers, do not
4140 modify the points-to sets of memory reachable from their
4141 arguments and do not add to the ESCAPED solution. */
4142 case BUILT_IN_SINCOS:
4143 case BUILT_IN_SINCOSF:
4144 case BUILT_IN_SINCOSL:
4145 case BUILT_IN_FREXP:
4146 case BUILT_IN_FREXPF:
4147 case BUILT_IN_FREXPL:
4148 case BUILT_IN_GAMMA_R:
4149 case BUILT_IN_GAMMAF_R:
4150 case BUILT_IN_GAMMAL_R:
4151 case BUILT_IN_LGAMMA_R:
4152 case BUILT_IN_LGAMMAF_R:
4153 case BUILT_IN_LGAMMAL_R:
4155 case BUILT_IN_MODFF:
4156 case BUILT_IN_MODFL:
4157 case BUILT_IN_REMQUO:
4158 case BUILT_IN_REMQUOF:
4159 case BUILT_IN_REMQUOL:
4162 /* Trampolines are special - they set up passing the static
4164 case BUILT_IN_INIT_TRAMPOLINE:
4166 tree tramp = gimple_call_arg (t, 0);
4167 tree nfunc = gimple_call_arg (t, 1);
4168 tree frame = gimple_call_arg (t, 2);
4170 struct constraint_expr lhs, *rhsp;
4173 varinfo_t nfi = NULL;
4174 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4175 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4178 lhs = get_function_part_constraint (nfi, fi_static_chain);
4179 get_constraint_for (frame, &rhsc);
4180 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
4181 process_constraint (new_constraint (lhs, *rhsp));
4182 VEC_free (ce_s, heap, rhsc);
4184 /* Make the frame point to the function for
4185 the trampoline adjustment call. */
4186 get_constraint_for (tramp, &lhsc);
4188 get_constraint_for (nfunc, &rhsc);
4189 process_all_all_constraints (lhsc, rhsc);
4190 VEC_free (ce_s, heap, rhsc);
4191 VEC_free (ce_s, heap, lhsc);
4196 /* Else fallthru to generic handling which will let
4197 the frame escape. */
4200 case BUILT_IN_ADJUST_TRAMPOLINE:
4202 tree tramp = gimple_call_arg (t, 0);
4203 tree res = gimple_call_lhs (t);
4204 if (in_ipa_mode && res)
4206 get_constraint_for (res, &lhsc);
4207 get_constraint_for (tramp, &rhsc);
4209 process_all_all_constraints (lhsc, rhsc);
4210 VEC_free (ce_s, heap, rhsc);
4211 VEC_free (ce_s, heap, lhsc);
4215 /* Variadic argument handling needs to be handled in IPA
4217 case BUILT_IN_VA_START:
4221 tree valist = gimple_call_arg (t, 0);
4222 struct constraint_expr rhs, *lhsp;
4224 /* The va_list gets access to pointers in variadic
4226 fi = lookup_vi_for_tree (cfun->decl);
4227 gcc_assert (fi != NULL);
4228 get_constraint_for (valist, &lhsc);
4230 rhs = get_function_part_constraint (fi, ~0);
4231 rhs.type = ADDRESSOF;
4232 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4233 process_constraint (new_constraint (*lhsp, rhs));
4234 VEC_free (ce_s, heap, lhsc);
4235 /* va_list is clobbered. */
4236 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4241 /* va_end doesn't have any effect that matters. */
4242 case BUILT_IN_VA_END:
4244 /* Alternate return. Simply give up for now. */
4245 case BUILT_IN_RETURN:
4249 || !(fi = get_vi_for_tree (cfun->decl)))
4250 make_constraint_from (get_varinfo (escaped_id), anything_id);
4251 else if (in_ipa_mode
4254 struct constraint_expr lhs, rhs;
4255 lhs = get_function_part_constraint (fi, fi_result);
4256 rhs.var = anything_id;
4259 process_constraint (new_constraint (lhs, rhs));
4263 /* printf-style functions may have hooks to set pointers to
4264 point to somewhere into the generated string. Leave them
4265 for a later excercise... */
4267 /* Fallthru to general call handling. */;
4271 && (!(fi = lookup_vi_for_tree (fndecl))
4272 || !fi->is_fn_info)))
4274 VEC(ce_s, heap) *rhsc = NULL;
4275 int flags = gimple_call_flags (t);
4277 /* Const functions can return their arguments and addresses
4278 of global memory but not of escaped memory. */
4279 if (flags & (ECF_CONST|ECF_NOVOPS))
4281 if (gimple_call_lhs (t)
4282 && could_have_pointers (gimple_call_lhs (t)))
4283 handle_const_call (t, &rhsc);
4285 /* Pure functions can return addresses in and of memory
4286 reachable from their arguments, but they are not an escape
4287 point for reachable memory of their arguments. */
4288 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4289 handle_pure_call (t, &rhsc);
4291 handle_rhs_call (t, &rhsc);
4292 if (gimple_call_lhs (t)
4293 && could_have_pointers (gimple_call_lhs (t)))
4294 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4295 VEC_free (ce_s, heap, rhsc);
4302 fi = get_fi_for_callee (t);
4304 /* Assign all the passed arguments to the appropriate incoming
4305 parameters of the function. */
4306 for (j = 0; j < gimple_call_num_args (t); j++)
4308 struct constraint_expr lhs ;
4309 struct constraint_expr *rhsp;
4310 tree arg = gimple_call_arg (t, j);
4312 if (!could_have_pointers (arg))
4315 get_constraint_for (arg, &rhsc);
4316 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4317 while (VEC_length (ce_s, rhsc) != 0)
4319 rhsp = VEC_last (ce_s, rhsc);
4320 process_constraint (new_constraint (lhs, *rhsp));
4321 VEC_pop (ce_s, rhsc);
4325 /* If we are returning a value, assign it to the result. */
4326 lhsop = gimple_call_lhs (t);
4328 && type_could_have_pointers (TREE_TYPE (lhsop)))
4330 struct constraint_expr rhs;
4331 struct constraint_expr *lhsp;
4333 get_constraint_for (lhsop, &lhsc);
4334 rhs = get_function_part_constraint (fi, fi_result);
4336 && DECL_RESULT (fndecl)
4337 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4339 VEC(ce_s, heap) *tem = NULL;
4340 VEC_safe_push (ce_s, heap, tem, &rhs);
4342 rhs = *VEC_index (ce_s, tem, 0);
4343 VEC_free(ce_s, heap, tem);
4345 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4346 process_constraint (new_constraint (*lhsp, rhs));
4349 /* If we pass the result decl by reference, honor that. */
4352 && DECL_RESULT (fndecl)
4353 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4355 struct constraint_expr lhs;
4356 struct constraint_expr *rhsp;
4358 get_constraint_for_address_of (lhsop, &rhsc);
4359 lhs = get_function_part_constraint (fi, fi_result);
4360 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4361 process_constraint (new_constraint (lhs, *rhsp));
4362 VEC_free (ce_s, heap, rhsc);
4365 /* If we use a static chain, pass it along. */
4366 if (gimple_call_chain (t))
4368 struct constraint_expr lhs;
4369 struct constraint_expr *rhsp;
4371 get_constraint_for (gimple_call_chain (t), &rhsc);
4372 lhs = get_function_part_constraint (fi, fi_static_chain);
4373 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4374 process_constraint (new_constraint (lhs, *rhsp));
4378 /* Otherwise, just a regular assignment statement. Only care about
4379 operations with pointer result, others are dealt with as escape
4380 points if they have pointer operands. */
4381 else if (is_gimple_assign (t)
4382 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4384 /* Otherwise, just a regular assignment statement. */
4385 tree lhsop = gimple_assign_lhs (t);
4386 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4388 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4389 do_structure_copy (lhsop, rhsop);
4392 struct constraint_expr temp;
4393 get_constraint_for (lhsop, &lhsc);
4395 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4396 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4397 gimple_assign_rhs2 (t), &rhsc);
4398 else if (gimple_assign_rhs_code (t) == BIT_AND_EXPR
4399 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4401 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4402 the pointer. Handle it by offsetting it by UNKNOWN. */
4403 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4406 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4407 && !(POINTER_TYPE_P (gimple_expr_type (t))
4408 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4409 || gimple_assign_single_p (t))
4410 get_constraint_for (rhsop, &rhsc);
4413 temp.type = ADDRESSOF;
4414 temp.var = anything_id;
4416 VEC_safe_push (ce_s, heap, rhsc, &temp);
4418 process_all_all_constraints (lhsc, rhsc);
4420 /* If there is a store to a global variable the rhs escapes. */
4421 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4423 && is_global_var (lhsop)
4425 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4426 make_escape_constraint (rhsop);
4427 /* If this is a conversion of a non-restrict pointer to a
4428 restrict pointer track it with a new heapvar. */
4429 else if (gimple_assign_cast_p (t)
4430 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4431 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4432 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4433 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4434 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4437 /* For conversions of pointers to non-pointers the pointer escapes. */
4438 else if (gimple_assign_cast_p (t)
4439 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4440 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4442 make_escape_constraint (gimple_assign_rhs1 (t));
4444 /* Handle escapes through return. */
4445 else if (gimple_code (t) == GIMPLE_RETURN
4446 && gimple_return_retval (t) != NULL_TREE
4447 && could_have_pointers (gimple_return_retval (t)))
4451 || !(fi = get_vi_for_tree (cfun->decl)))
4452 make_escape_constraint (gimple_return_retval (t));
4453 else if (in_ipa_mode
4456 struct constraint_expr lhs ;
4457 struct constraint_expr *rhsp;
4460 lhs = get_function_part_constraint (fi, fi_result);
4461 get_constraint_for (gimple_return_retval (t), &rhsc);
4462 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4463 process_constraint (new_constraint (lhs, *rhsp));
4466 /* Handle asms conservatively by adding escape constraints to everything. */
4467 else if (gimple_code (t) == GIMPLE_ASM)
4469 unsigned i, noutputs;
4470 const char **oconstraints;
4471 const char *constraint;
4472 bool allows_mem, allows_reg, is_inout;
4474 noutputs = gimple_asm_noutputs (t);
4475 oconstraints = XALLOCAVEC (const char *, noutputs);
4477 for (i = 0; i < noutputs; ++i)
4479 tree link = gimple_asm_output_op (t, i);
4480 tree op = TREE_VALUE (link);
4482 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4483 oconstraints[i] = constraint;
4484 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4485 &allows_reg, &is_inout);
4487 /* A memory constraint makes the address of the operand escape. */
4488 if (!allows_reg && allows_mem)
4489 make_escape_constraint (build_fold_addr_expr (op));
4491 /* The asm may read global memory, so outputs may point to
4492 any global memory. */
4493 if (op && could_have_pointers (op))
4495 VEC(ce_s, heap) *lhsc = NULL;
4496 struct constraint_expr rhsc, *lhsp;
4498 get_constraint_for (op, &lhsc);
4499 rhsc.var = nonlocal_id;
4502 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4503 process_constraint (new_constraint (*lhsp, rhsc));
4504 VEC_free (ce_s, heap, lhsc);
4507 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4509 tree link = gimple_asm_input_op (t, i);
4510 tree op = TREE_VALUE (link);
4512 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4514 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4515 &allows_mem, &allows_reg);
4517 /* A memory constraint makes the address of the operand escape. */
4518 if (!allows_reg && allows_mem)
4519 make_escape_constraint (build_fold_addr_expr (op));
4520 /* Strictly we'd only need the constraint to ESCAPED if
4521 the asm clobbers memory, otherwise using something
4522 along the lines of per-call clobbers/uses would be enough. */
4523 else if (op && could_have_pointers (op))
4524 make_escape_constraint (op);
4528 VEC_free (ce_s, heap, rhsc);
4529 VEC_free (ce_s, heap, lhsc);
4533 /* Create a constraint adding to the clobber set of FI the memory
4534 pointed to by PTR. */
4537 process_ipa_clobber (varinfo_t fi, tree ptr)
4539 VEC(ce_s, heap) *ptrc = NULL;
4540 struct constraint_expr *c, lhs;
4542 get_constraint_for (ptr, &ptrc);
4543 lhs = get_function_part_constraint (fi, fi_clobbers);
4544 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4545 process_constraint (new_constraint (lhs, *c));
4546 VEC_free (ce_s, heap, ptrc);
4549 /* Walk statement T setting up clobber and use constraints according to the
4550 references found in T. This function is a main part of the
4551 IPA constraint builder. */
4554 find_func_clobbers (gimple origt)
4557 VEC(ce_s, heap) *lhsc = NULL;
4558 VEC(ce_s, heap) *rhsc = NULL;
4561 /* Add constraints for clobbered/used in IPA mode.
4562 We are not interested in what automatic variables are clobbered
4563 or used as we only use the information in the caller to which
4564 they do not escape. */
4565 gcc_assert (in_ipa_mode);
4567 /* If the stmt refers to memory in any way it better had a VUSE. */
4568 if (gimple_vuse (t) == NULL_TREE)
4571 /* We'd better have function information for the current function. */
4572 fi = lookup_vi_for_tree (cfun->decl);
4573 gcc_assert (fi != NULL);
4575 /* Account for stores in assignments and calls. */
4576 if (gimple_vdef (t) != NULL_TREE
4577 && gimple_has_lhs (t))
4579 tree lhs = gimple_get_lhs (t);
4581 while (handled_component_p (tem))
4582 tem = TREE_OPERAND (tem, 0);
4584 && !auto_var_in_fn_p (tem, cfun->decl))
4585 || INDIRECT_REF_P (tem)
4586 || (TREE_CODE (tem) == MEM_REF
4587 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4589 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4591 struct constraint_expr lhsc, *rhsp;
4593 lhsc = get_function_part_constraint (fi, fi_clobbers);
4594 get_constraint_for_address_of (lhs, &rhsc);
4595 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4596 process_constraint (new_constraint (lhsc, *rhsp));
4597 VEC_free (ce_s, heap, rhsc);
4601 /* Account for uses in assigments and returns. */
4602 if (gimple_assign_single_p (t)
4603 || (gimple_code (t) == GIMPLE_RETURN
4604 && gimple_return_retval (t) != NULL_TREE))
4606 tree rhs = (gimple_assign_single_p (t)
4607 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4609 while (handled_component_p (tem))
4610 tem = TREE_OPERAND (tem, 0);
4612 && !auto_var_in_fn_p (tem, cfun->decl))
4613 || INDIRECT_REF_P (tem)
4614 || (TREE_CODE (tem) == MEM_REF
4615 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4617 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4619 struct constraint_expr lhs, *rhsp;
4621 lhs = get_function_part_constraint (fi, fi_uses);
4622 get_constraint_for_address_of (rhs, &rhsc);
4623 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4624 process_constraint (new_constraint (lhs, *rhsp));
4625 VEC_free (ce_s, heap, rhsc);
4629 if (is_gimple_call (t))
4631 varinfo_t cfi = NULL;
4632 tree decl = gimple_call_fndecl (t);
4633 struct constraint_expr lhs, rhs;
4636 /* For builtins we do not have separate function info. For those
4637 we do not generate escapes for we have to generate clobbers/uses. */
4639 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4640 switch (DECL_FUNCTION_CODE (decl))
4642 /* The following functions use and clobber memory pointed to
4643 by their arguments. */
4644 case BUILT_IN_STRCPY:
4645 case BUILT_IN_STRNCPY:
4646 case BUILT_IN_BCOPY:
4647 case BUILT_IN_MEMCPY:
4648 case BUILT_IN_MEMMOVE:
4649 case BUILT_IN_MEMPCPY:
4650 case BUILT_IN_STPCPY:
4651 case BUILT_IN_STPNCPY:
4652 case BUILT_IN_STRCAT:
4653 case BUILT_IN_STRNCAT:
4655 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4656 == BUILT_IN_BCOPY ? 1 : 0));
4657 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4658 == BUILT_IN_BCOPY ? 0 : 1));
4660 struct constraint_expr *rhsp, *lhsp;
4661 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4662 lhs = get_function_part_constraint (fi, fi_clobbers);
4663 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4664 process_constraint (new_constraint (lhs, *lhsp));
4665 VEC_free (ce_s, heap, lhsc);
4666 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4667 lhs = get_function_part_constraint (fi, fi_uses);
4668 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4669 process_constraint (new_constraint (lhs, *rhsp));
4670 VEC_free (ce_s, heap, rhsc);
4673 /* The following function clobbers memory pointed to by
4675 case BUILT_IN_MEMSET:
4677 tree dest = gimple_call_arg (t, 0);
4680 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4681 lhs = get_function_part_constraint (fi, fi_clobbers);
4682 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4683 process_constraint (new_constraint (lhs, *lhsp));
4684 VEC_free (ce_s, heap, lhsc);
4687 /* The following functions clobber their second and third
4689 case BUILT_IN_SINCOS:
4690 case BUILT_IN_SINCOSF:
4691 case BUILT_IN_SINCOSL:
4693 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4694 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4697 /* The following functions clobber their second argument. */
4698 case BUILT_IN_FREXP:
4699 case BUILT_IN_FREXPF:
4700 case BUILT_IN_FREXPL:
4701 case BUILT_IN_LGAMMA_R:
4702 case BUILT_IN_LGAMMAF_R:
4703 case BUILT_IN_LGAMMAL_R:
4704 case BUILT_IN_GAMMA_R:
4705 case BUILT_IN_GAMMAF_R:
4706 case BUILT_IN_GAMMAL_R:
4708 case BUILT_IN_MODFF:
4709 case BUILT_IN_MODFL:
4711 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4714 /* The following functions clobber their third argument. */
4715 case BUILT_IN_REMQUO:
4716 case BUILT_IN_REMQUOF:
4717 case BUILT_IN_REMQUOL:
4719 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4722 /* The following functions neither read nor clobber memory. */
4725 /* Trampolines are of no interest to us. */
4726 case BUILT_IN_INIT_TRAMPOLINE:
4727 case BUILT_IN_ADJUST_TRAMPOLINE:
4729 case BUILT_IN_VA_START:
4730 case BUILT_IN_VA_END:
4732 /* printf-style functions may have hooks to set pointers to
4733 point to somewhere into the generated string. Leave them
4734 for a later excercise... */
4736 /* Fallthru to general call handling. */;
4739 /* Parameters passed by value are used. */
4740 lhs = get_function_part_constraint (fi, fi_uses);
4741 for (i = 0; i < gimple_call_num_args (t); i++)
4743 struct constraint_expr *rhsp;
4744 tree arg = gimple_call_arg (t, i);
4746 if (TREE_CODE (arg) == SSA_NAME
4747 || is_gimple_min_invariant (arg))
4750 get_constraint_for_address_of (arg, &rhsc);
4751 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4752 process_constraint (new_constraint (lhs, *rhsp));
4753 VEC_free (ce_s, heap, rhsc);
4756 /* Build constraints for propagating clobbers/uses along the
4758 cfi = get_fi_for_callee (t);
4759 if (cfi->id == anything_id)
4761 if (gimple_vdef (t))
4762 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4764 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4769 /* For callees without function info (that's external functions),
4770 ESCAPED is clobbered and used. */
4771 if (gimple_call_fndecl (t)
4772 && !cfi->is_fn_info)
4776 if (gimple_vdef (t))
4777 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4779 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4781 /* Also honor the call statement use/clobber info. */
4782 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4783 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4785 if ((vi = lookup_call_use_vi (t)) != NULL)
4786 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4791 /* Otherwise the caller clobbers and uses what the callee does.
4792 ??? This should use a new complex constraint that filters
4793 local variables of the callee. */
4794 if (gimple_vdef (t))
4796 lhs = get_function_part_constraint (fi, fi_clobbers);
4797 rhs = get_function_part_constraint (cfi, fi_clobbers);
4798 process_constraint (new_constraint (lhs, rhs));
4800 lhs = get_function_part_constraint (fi, fi_uses);
4801 rhs = get_function_part_constraint (cfi, fi_uses);
4802 process_constraint (new_constraint (lhs, rhs));
4804 else if (gimple_code (t) == GIMPLE_ASM)
4806 /* ??? Ick. We can do better. */
4807 if (gimple_vdef (t))
4808 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4810 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4814 VEC_free (ce_s, heap, rhsc);
4818 /* Find the first varinfo in the same variable as START that overlaps with
4819 OFFSET. Return NULL if we can't find one. */
4822 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4824 /* If the offset is outside of the variable, bail out. */
4825 if (offset >= start->fullsize)
4828 /* If we cannot reach offset from start, lookup the first field
4829 and start from there. */
4830 if (start->offset > offset)
4831 start = lookup_vi_for_tree (start->decl);
4835 /* We may not find a variable in the field list with the actual
4836 offset when when we have glommed a structure to a variable.
4837 In that case, however, offset should still be within the size
4839 if (offset >= start->offset
4840 && (offset - start->offset) < start->size)
4849 /* Find the first varinfo in the same variable as START that overlaps with
4850 OFFSET. If there is no such varinfo the varinfo directly preceding
4851 OFFSET is returned. */
4854 first_or_preceding_vi_for_offset (varinfo_t start,
4855 unsigned HOST_WIDE_INT offset)
4857 /* If we cannot reach offset from start, lookup the first field
4858 and start from there. */
4859 if (start->offset > offset)
4860 start = lookup_vi_for_tree (start->decl);
4862 /* We may not find a variable in the field list with the actual
4863 offset when when we have glommed a structure to a variable.
4864 In that case, however, offset should still be within the size
4866 If we got beyond the offset we look for return the field
4867 directly preceding offset which may be the last field. */
4869 && offset >= start->offset
4870 && !((offset - start->offset) < start->size))
4871 start = start->next;
4877 /* This structure is used during pushing fields onto the fieldstack
4878 to track the offset of the field, since bitpos_of_field gives it
4879 relative to its immediate containing type, and we want it relative
4880 to the ultimate containing object. */
4884 /* Offset from the base of the base containing object to this field. */
4885 HOST_WIDE_INT offset;
4887 /* Size, in bits, of the field. */
4888 unsigned HOST_WIDE_INT size;
4890 unsigned has_unknown_size : 1;
4892 unsigned may_have_pointers : 1;
4894 unsigned only_restrict_pointers : 1;
4896 typedef struct fieldoff fieldoff_s;
4898 DEF_VEC_O(fieldoff_s);
4899 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4901 /* qsort comparison function for two fieldoff's PA and PB */
4904 fieldoff_compare (const void *pa, const void *pb)
4906 const fieldoff_s *foa = (const fieldoff_s *)pa;
4907 const fieldoff_s *fob = (const fieldoff_s *)pb;
4908 unsigned HOST_WIDE_INT foasize, fobsize;
4910 if (foa->offset < fob->offset)
4912 else if (foa->offset > fob->offset)
4915 foasize = foa->size;
4916 fobsize = fob->size;
4917 if (foasize < fobsize)
4919 else if (foasize > fobsize)
4924 /* Sort a fieldstack according to the field offset and sizes. */
4926 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4928 qsort (VEC_address (fieldoff_s, fieldstack),
4929 VEC_length (fieldoff_s, fieldstack),
4930 sizeof (fieldoff_s),
4934 /* Return true if V is a tree that we can have subvars for.
4935 Normally, this is any aggregate type. Also complex
4936 types which are not gimple registers can have subvars. */
4939 var_can_have_subvars (const_tree v)
4941 /* Volatile variables should never have subvars. */
4942 if (TREE_THIS_VOLATILE (v))
4945 /* Non decls or memory tags can never have subvars. */
4949 /* Aggregates without overlapping fields can have subvars. */
4950 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4956 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4957 the fields of TYPE onto fieldstack, recording their offsets along
4960 OFFSET is used to keep track of the offset in this entire
4961 structure, rather than just the immediately containing structure.
4962 Returns false if the caller is supposed to handle the field we
4966 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4967 HOST_WIDE_INT offset, bool must_have_pointers_p)
4970 bool empty_p = true;
4972 if (TREE_CODE (type) != RECORD_TYPE)
4975 /* If the vector of fields is growing too big, bail out early.
4976 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4978 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4981 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4982 if (TREE_CODE (field) == FIELD_DECL)
4985 HOST_WIDE_INT foff = bitpos_of_field (field);
4987 if (!var_can_have_subvars (field)
4988 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4989 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4991 else if (!push_fields_onto_fieldstack
4992 (TREE_TYPE (field), fieldstack, offset + foff,
4993 must_have_pointers_p)
4994 && (DECL_SIZE (field)
4995 && !integer_zerop (DECL_SIZE (field))))
4996 /* Empty structures may have actual size, like in C++. So
4997 see if we didn't push any subfields and the size is
4998 nonzero, push the field onto the stack. */
5003 fieldoff_s *pair = NULL;
5004 bool has_unknown_size = false;
5006 if (!VEC_empty (fieldoff_s, *fieldstack))
5007 pair = VEC_last (fieldoff_s, *fieldstack);
5009 if (!DECL_SIZE (field)
5010 || !host_integerp (DECL_SIZE (field), 1))
5011 has_unknown_size = true;
5013 /* If adjacent fields do not contain pointers merge them. */
5015 && !pair->may_have_pointers
5016 && !pair->has_unknown_size
5017 && !has_unknown_size
5018 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
5019 && !must_have_pointers_p
5020 && !could_have_pointers (field))
5022 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5026 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5027 pair->offset = offset + foff;
5028 pair->has_unknown_size = has_unknown_size;
5029 if (!has_unknown_size)
5030 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5033 pair->may_have_pointers
5034 = must_have_pointers_p || could_have_pointers (field);
5035 pair->only_restrict_pointers
5036 = (!has_unknown_size
5037 && POINTER_TYPE_P (TREE_TYPE (field))
5038 && TYPE_RESTRICT (TREE_TYPE (field)));
5048 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5049 if it is a varargs function. */
5052 count_num_arguments (tree decl, bool *is_varargs)
5054 unsigned int num = 0;
5057 /* Capture named arguments for K&R functions. They do not
5058 have a prototype and thus no TYPE_ARG_TYPES. */
5059 for (t = DECL_ARGUMENTS (decl); t; t = TREE_CHAIN (t))
5062 /* Check if the function has variadic arguments. */
5063 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5064 if (TREE_VALUE (t) == void_type_node)
5072 /* Creation function node for DECL, using NAME, and return the index
5073 of the variable we've created for the function. */
5076 create_function_info_for (tree decl, const char *name)
5078 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5079 varinfo_t vi, prev_vi;
5082 bool is_varargs = false;
5083 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5085 /* Create the variable info. */
5087 vi = new_var_info (decl, name);
5090 vi->fullsize = fi_parm_base + num_args;
5092 vi->may_have_pointers = false;
5095 insert_vi_for_tree (vi->decl, vi);
5099 /* Create a variable for things the function clobbers and one for
5100 things the function uses. */
5102 varinfo_t clobbervi, usevi;
5103 const char *newname;
5106 asprintf (&tempname, "%s.clobber", name);
5107 newname = ggc_strdup (tempname);
5110 clobbervi = new_var_info (NULL, newname);
5111 clobbervi->offset = fi_clobbers;
5112 clobbervi->size = 1;
5113 clobbervi->fullsize = vi->fullsize;
5114 clobbervi->is_full_var = true;
5115 clobbervi->is_global_var = false;
5116 gcc_assert (prev_vi->offset < clobbervi->offset);
5117 prev_vi->next = clobbervi;
5118 prev_vi = clobbervi;
5120 asprintf (&tempname, "%s.use", name);
5121 newname = ggc_strdup (tempname);
5124 usevi = new_var_info (NULL, newname);
5125 usevi->offset = fi_uses;
5127 usevi->fullsize = vi->fullsize;
5128 usevi->is_full_var = true;
5129 usevi->is_global_var = false;
5130 gcc_assert (prev_vi->offset < usevi->offset);
5131 prev_vi->next = usevi;
5135 /* And one for the static chain. */
5136 if (fn->static_chain_decl != NULL_TREE)
5139 const char *newname;
5142 asprintf (&tempname, "%s.chain", name);
5143 newname = ggc_strdup (tempname);
5146 chainvi = new_var_info (fn->static_chain_decl, newname);
5147 chainvi->offset = fi_static_chain;
5149 chainvi->fullsize = vi->fullsize;
5150 chainvi->is_full_var = true;
5151 chainvi->is_global_var = false;
5152 gcc_assert (prev_vi->offset < chainvi->offset);
5153 prev_vi->next = chainvi;
5155 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5158 /* Create a variable for the return var. */
5159 if (DECL_RESULT (decl) != NULL
5160 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5163 const char *newname;
5165 tree resultdecl = decl;
5167 if (DECL_RESULT (decl))
5168 resultdecl = DECL_RESULT (decl);
5170 asprintf (&tempname, "%s.result", name);
5171 newname = ggc_strdup (tempname);
5174 resultvi = new_var_info (resultdecl, newname);
5175 resultvi->offset = fi_result;
5177 resultvi->fullsize = vi->fullsize;
5178 resultvi->is_full_var = true;
5179 if (DECL_RESULT (decl))
5180 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5181 gcc_assert (prev_vi->offset < resultvi->offset);
5182 prev_vi->next = resultvi;
5184 if (DECL_RESULT (decl))
5185 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5188 /* Set up variables for each argument. */
5189 arg = DECL_ARGUMENTS (decl);
5190 for (i = 0; i < num_args; i++)
5193 const char *newname;
5195 tree argdecl = decl;
5200 asprintf (&tempname, "%s.arg%d", name, i);
5201 newname = ggc_strdup (tempname);
5204 argvi = new_var_info (argdecl, newname);
5205 argvi->offset = fi_parm_base + i;
5207 argvi->is_full_var = true;
5208 argvi->fullsize = vi->fullsize;
5210 argvi->may_have_pointers = could_have_pointers (arg);
5211 gcc_assert (prev_vi->offset < argvi->offset);
5212 prev_vi->next = argvi;
5216 insert_vi_for_tree (arg, argvi);
5217 arg = TREE_CHAIN (arg);
5221 /* Add one representative for all further args. */
5225 const char *newname;
5229 asprintf (&tempname, "%s.varargs", name);
5230 newname = ggc_strdup (tempname);
5233 /* We need sth that can be pointed to for va_start. */
5234 decl = create_tmp_var_raw (ptr_type_node, name);
5237 argvi = new_var_info (decl, newname);
5238 argvi->offset = fi_parm_base + num_args;
5240 argvi->is_full_var = true;
5241 argvi->is_heap_var = true;
5242 argvi->fullsize = vi->fullsize;
5243 gcc_assert (prev_vi->offset < argvi->offset);
5244 prev_vi->next = argvi;
5252 /* Return true if FIELDSTACK contains fields that overlap.
5253 FIELDSTACK is assumed to be sorted by offset. */
5256 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5258 fieldoff_s *fo = NULL;
5260 HOST_WIDE_INT lastoffset = -1;
5262 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5264 if (fo->offset == lastoffset)
5266 lastoffset = fo->offset;
5271 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5272 This will also create any varinfo structures necessary for fields
5276 create_variable_info_for_1 (tree decl, const char *name)
5278 varinfo_t vi, newvi;
5279 tree decl_type = TREE_TYPE (decl);
5280 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5281 VEC (fieldoff_s,heap) *fieldstack = NULL;
5286 || !host_integerp (declsize, 1))
5288 vi = new_var_info (decl, name);
5292 vi->is_unknown_size_var = true;
5293 vi->is_full_var = true;
5294 vi->may_have_pointers = could_have_pointers (decl);
5298 /* Collect field information. */
5299 if (use_field_sensitive
5300 && var_can_have_subvars (decl)
5301 /* ??? Force us to not use subfields for global initializers
5302 in IPA mode. Else we'd have to parse arbitrary initializers. */
5304 && is_global_var (decl)
5305 && DECL_INITIAL (decl)))
5307 fieldoff_s *fo = NULL;
5308 bool notokay = false;
5311 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5313 || DECL_EXTERNAL (decl)
5314 || TREE_ADDRESSABLE (decl));
5316 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5317 if (fo->has_unknown_size
5324 /* We can't sort them if we have a field with a variable sized type,
5325 which will make notokay = true. In that case, we are going to return
5326 without creating varinfos for the fields anyway, so sorting them is a
5330 sort_fieldstack (fieldstack);
5331 /* Due to some C++ FE issues, like PR 22488, we might end up
5332 what appear to be overlapping fields even though they,
5333 in reality, do not overlap. Until the C++ FE is fixed,
5334 we will simply disable field-sensitivity for these cases. */
5335 notokay = check_for_overlaps (fieldstack);
5339 VEC_free (fieldoff_s, heap, fieldstack);
5342 /* If we didn't end up collecting sub-variables create a full
5343 variable for the decl. */
5344 if (VEC_length (fieldoff_s, fieldstack) <= 1
5345 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5347 vi = new_var_info (decl, name);
5349 vi->may_have_pointers = could_have_pointers (decl);
5350 vi->fullsize = TREE_INT_CST_LOW (declsize);
5351 vi->size = vi->fullsize;
5352 vi->is_full_var = true;
5353 VEC_free (fieldoff_s, heap, fieldstack);
5357 vi = new_var_info (decl, name);
5358 vi->fullsize = TREE_INT_CST_LOW (declsize);
5359 for (i = 0, newvi = vi;
5360 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5361 ++i, newvi = newvi->next)
5363 const char *newname = "NULL";
5368 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5369 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5370 newname = ggc_strdup (tempname);
5373 newvi->name = newname;
5374 newvi->offset = fo->offset;
5375 newvi->size = fo->size;
5376 newvi->fullsize = vi->fullsize;
5377 newvi->may_have_pointers = fo->may_have_pointers;
5378 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5379 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5380 newvi->next = new_var_info (decl, name);
5383 VEC_free (fieldoff_s, heap, fieldstack);
5389 create_variable_info_for (tree decl, const char *name)
5391 varinfo_t vi = create_variable_info_for_1 (decl, name);
5392 unsigned int id = vi->id;
5394 insert_vi_for_tree (decl, vi);
5396 /* Create initial constraints for globals. */
5397 for (; vi; vi = vi->next)
5399 if (!vi->may_have_pointers
5400 || !vi->is_global_var)
5403 /* Mark global restrict qualified pointers. */
5404 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5405 && TYPE_RESTRICT (TREE_TYPE (decl)))
5406 || vi->only_restrict_pointers)
5407 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5409 /* For escaped variables initialize them from nonlocal. */
5411 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5412 make_copy_constraint (vi, nonlocal_id);
5414 /* If this is a global variable with an initializer and we are in
5415 IPA mode generate constraints for it. In non-IPA mode
5416 the initializer from nonlocal is all we need. */
5418 && DECL_INITIAL (decl))
5420 VEC (ce_s, heap) *rhsc = NULL;
5421 struct constraint_expr lhs, *rhsp;
5423 get_constraint_for (DECL_INITIAL (decl), &rhsc);
5427 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5428 process_constraint (new_constraint (lhs, *rhsp));
5429 /* If this is a variable that escapes from the unit
5430 the initializer escapes as well. */
5431 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5433 lhs.var = escaped_id;
5436 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5437 process_constraint (new_constraint (lhs, *rhsp));
5439 VEC_free (ce_s, heap, rhsc);
5446 /* Print out the points-to solution for VAR to FILE. */
5449 dump_solution_for_var (FILE *file, unsigned int var)
5451 varinfo_t vi = get_varinfo (var);
5455 /* Dump the solution for unified vars anyway, this avoids difficulties
5456 in scanning dumps in the testsuite. */
5457 fprintf (file, "%s = { ", vi->name);
5458 vi = get_varinfo (find (var));
5459 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5460 fprintf (file, "%s ", get_varinfo (i)->name);
5461 fprintf (file, "}");
5463 /* But note when the variable was unified. */
5465 fprintf (file, " same as %s", vi->name);
5467 fprintf (file, "\n");
5470 /* Print the points-to solution for VAR to stdout. */
5473 debug_solution_for_var (unsigned int var)
5475 dump_solution_for_var (stdout, var);
5478 /* Create varinfo structures for all of the variables in the
5479 function for intraprocedural mode. */
5482 intra_create_variable_infos (void)
5486 /* For each incoming pointer argument arg, create the constraint ARG
5487 = NONLOCAL or a dummy variable if it is a restrict qualified
5488 passed-by-reference argument. */
5489 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
5493 if (!could_have_pointers (t))
5496 /* For restrict qualified pointers to objects passed by
5497 reference build a real representative for the pointed-to object. */
5498 if (DECL_BY_REFERENCE (t)
5499 && POINTER_TYPE_P (TREE_TYPE (t))
5500 && TYPE_RESTRICT (TREE_TYPE (t)))
5502 struct constraint_expr lhsc, rhsc;
5504 tree heapvar = heapvar_lookup (t, 0);
5505 if (heapvar == NULL_TREE)
5508 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5510 DECL_EXTERNAL (heapvar) = 1;
5511 heapvar_insert (t, 0, heapvar);
5512 ann = get_var_ann (heapvar);
5513 ann->is_heapvar = 1;
5515 if (gimple_referenced_vars (cfun))
5516 add_referenced_var (heapvar);
5517 lhsc.var = get_vi_for_tree (t)->id;
5520 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5521 rhsc.type = ADDRESSOF;
5523 process_constraint (new_constraint (lhsc, rhsc));
5524 vi->is_restrict_var = 1;
5528 for (p = get_vi_for_tree (t); p; p = p->next)
5530 if (p->may_have_pointers)
5531 make_constraint_from (p, nonlocal_id);
5532 if (p->only_restrict_pointers)
5533 make_constraint_from_restrict (p, "PARM_RESTRICT");
5535 if (POINTER_TYPE_P (TREE_TYPE (t))
5536 && TYPE_RESTRICT (TREE_TYPE (t)))
5537 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5540 /* Add a constraint for a result decl that is passed by reference. */
5541 if (DECL_RESULT (cfun->decl)
5542 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5544 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5546 for (p = result_vi; p; p = p->next)
5547 make_constraint_from (p, nonlocal_id);
5550 /* Add a constraint for the incoming static chain parameter. */
5551 if (cfun->static_chain_decl != NULL_TREE)
5553 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5555 for (p = chain_vi; p; p = p->next)
5556 make_constraint_from (p, nonlocal_id);
5560 /* Structure used to put solution bitmaps in a hashtable so they can
5561 be shared among variables with the same points-to set. */
5563 typedef struct shared_bitmap_info
5567 } *shared_bitmap_info_t;
5568 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5570 static htab_t shared_bitmap_table;
5572 /* Hash function for a shared_bitmap_info_t */
5575 shared_bitmap_hash (const void *p)
5577 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5578 return bi->hashcode;
5581 /* Equality function for two shared_bitmap_info_t's. */
5584 shared_bitmap_eq (const void *p1, const void *p2)
5586 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5587 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5588 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5591 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5592 existing instance if there is one, NULL otherwise. */
5595 shared_bitmap_lookup (bitmap pt_vars)
5598 struct shared_bitmap_info sbi;
5600 sbi.pt_vars = pt_vars;
5601 sbi.hashcode = bitmap_hash (pt_vars);
5603 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5604 sbi.hashcode, NO_INSERT);
5608 return ((shared_bitmap_info_t) *slot)->pt_vars;
5612 /* Add a bitmap to the shared bitmap hashtable. */
5615 shared_bitmap_add (bitmap pt_vars)
5618 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5620 sbi->pt_vars = pt_vars;
5621 sbi->hashcode = bitmap_hash (pt_vars);
5623 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5624 sbi->hashcode, INSERT);
5625 gcc_assert (!*slot);
5626 *slot = (void *) sbi;
5630 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5633 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5638 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5640 varinfo_t vi = get_varinfo (i);
5642 /* The only artificial variables that are allowed in a may-alias
5643 set are heap variables. */
5644 if (vi->is_artificial_var && !vi->is_heap_var)
5647 if (TREE_CODE (vi->decl) == VAR_DECL
5648 || TREE_CODE (vi->decl) == PARM_DECL
5649 || TREE_CODE (vi->decl) == RESULT_DECL)
5651 /* If we are in IPA mode we will not recompute points-to
5652 sets after inlining so make sure they stay valid. */
5654 && !DECL_PT_UID_SET_P (vi->decl))
5655 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5657 /* Add the decl to the points-to set. Note that the points-to
5658 set contains global variables. */
5659 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5660 if (vi->is_global_var)
5661 pt->vars_contains_global = true;
5667 /* Compute the points-to solution *PT for the variable VI. */
5670 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5674 bitmap finished_solution;
5678 memset (pt, 0, sizeof (struct pt_solution));
5680 /* This variable may have been collapsed, let's get the real
5682 vi = get_varinfo (find (orig_vi->id));
5684 /* Translate artificial variables into SSA_NAME_PTR_INFO
5686 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5688 varinfo_t vi = get_varinfo (i);
5690 if (vi->is_artificial_var)
5692 if (vi->id == nothing_id)
5694 else if (vi->id == escaped_id)
5697 pt->ipa_escaped = 1;
5701 else if (vi->id == nonlocal_id)
5703 else if (vi->is_heap_var)
5704 /* We represent heapvars in the points-to set properly. */
5706 else if (vi->id == readonly_id)
5709 else if (vi->id == anything_id
5710 || vi->id == integer_id)
5713 if (vi->is_restrict_var)
5714 pt->vars_contains_restrict = true;
5717 /* Instead of doing extra work, simply do not create
5718 elaborate points-to information for pt_anything pointers. */
5720 && (orig_vi->is_artificial_var
5721 || !pt->vars_contains_restrict))
5724 /* Share the final set of variables when possible. */
5725 finished_solution = BITMAP_GGC_ALLOC ();
5726 stats.points_to_sets_created++;
5728 set_uids_in_ptset (finished_solution, vi->solution, pt);
5729 result = shared_bitmap_lookup (finished_solution);
5732 shared_bitmap_add (finished_solution);
5733 pt->vars = finished_solution;
5738 bitmap_clear (finished_solution);
5742 /* Given a pointer variable P, fill in its points-to set. */
5745 find_what_p_points_to (tree p)
5747 struct ptr_info_def *pi;
5751 /* For parameters, get at the points-to set for the actual parm
5753 if (TREE_CODE (p) == SSA_NAME
5754 && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5755 && SSA_NAME_IS_DEFAULT_DEF (p))
5756 lookup_p = SSA_NAME_VAR (p);
5758 vi = lookup_vi_for_tree (lookup_p);
5762 pi = get_ptr_info (p);
5763 find_what_var_points_to (vi, &pi->pt);
5767 /* Query statistics for points-to solutions. */
5770 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5771 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5772 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5773 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5777 dump_pta_stats (FILE *s)
5779 fprintf (s, "\nPTA query stats:\n");
5780 fprintf (s, " pt_solution_includes: "
5781 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5782 HOST_WIDE_INT_PRINT_DEC" queries\n",
5783 pta_stats.pt_solution_includes_no_alias,
5784 pta_stats.pt_solution_includes_no_alias
5785 + pta_stats.pt_solution_includes_may_alias);
5786 fprintf (s, " pt_solutions_intersect: "
5787 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5788 HOST_WIDE_INT_PRINT_DEC" queries\n",
5789 pta_stats.pt_solutions_intersect_no_alias,
5790 pta_stats.pt_solutions_intersect_no_alias
5791 + pta_stats.pt_solutions_intersect_may_alias);
5795 /* Reset the points-to solution *PT to a conservative default
5796 (point to anything). */
5799 pt_solution_reset (struct pt_solution *pt)
5801 memset (pt, 0, sizeof (struct pt_solution));
5802 pt->anything = true;
5805 /* Set the points-to solution *PT to point only to the variables
5806 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5807 global variables and VARS_CONTAINS_RESTRICT specifies whether
5808 it contains restrict tag variables. */
5811 pt_solution_set (struct pt_solution *pt, bitmap vars,
5812 bool vars_contains_global, bool vars_contains_restrict)
5814 memset (pt, 0, sizeof (struct pt_solution));
5816 pt->vars_contains_global = vars_contains_global;
5817 pt->vars_contains_restrict = vars_contains_restrict;
5820 /* Computes the union of the points-to solutions *DEST and *SRC and
5821 stores the result in *DEST. This changes the points-to bitmap
5822 of *DEST and thus may not be used if that might be shared.
5823 The points-to bitmap of *SRC and *DEST will not be shared after
5824 this function if they were not before. */
5827 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5829 dest->anything |= src->anything;
5832 pt_solution_reset (dest);
5836 dest->nonlocal |= src->nonlocal;
5837 dest->escaped |= src->escaped;
5838 dest->ipa_escaped |= src->ipa_escaped;
5839 dest->null |= src->null;
5840 dest->vars_contains_global |= src->vars_contains_global;
5841 dest->vars_contains_restrict |= src->vars_contains_restrict;
5846 dest->vars = BITMAP_GGC_ALLOC ();
5847 bitmap_ior_into (dest->vars, src->vars);
5850 /* Return true if the points-to solution *PT is empty. */
5853 pt_solution_empty_p (struct pt_solution *pt)
5860 && !bitmap_empty_p (pt->vars))
5863 /* If the solution includes ESCAPED, check if that is empty. */
5865 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5868 /* If the solution includes ESCAPED, check if that is empty. */
5870 && !pt_solution_empty_p (&ipa_escaped_pt))
5876 /* Return true if the points-to solution *PT includes global memory. */
5879 pt_solution_includes_global (struct pt_solution *pt)
5883 || pt->vars_contains_global)
5887 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5889 if (pt->ipa_escaped)
5890 return pt_solution_includes_global (&ipa_escaped_pt);
5892 /* ??? This predicate is not correct for the IPA-PTA solution
5893 as we do not properly distinguish between unit escape points
5894 and global variables. */
5895 if (cfun->gimple_df->ipa_pta)
5901 /* Return true if the points-to solution *PT includes the variable
5902 declaration DECL. */
5905 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5911 && is_global_var (decl))
5915 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5918 /* If the solution includes ESCAPED, check it. */
5920 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5923 /* If the solution includes ESCAPED, check it. */
5925 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5932 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5934 bool res = pt_solution_includes_1 (pt, decl);
5936 ++pta_stats.pt_solution_includes_may_alias;
5938 ++pta_stats.pt_solution_includes_no_alias;
5942 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5946 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5948 if (pt1->anything || pt2->anything)
5951 /* If either points to unknown global memory and the other points to
5952 any global memory they alias. */
5955 || pt2->vars_contains_global))
5957 && pt1->vars_contains_global))
5960 /* Check the escaped solution if required. */
5961 if ((pt1->escaped || pt2->escaped)
5962 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5964 /* If both point to escaped memory and that solution
5965 is not empty they alias. */
5966 if (pt1->escaped && pt2->escaped)
5969 /* If either points to escaped memory see if the escaped solution
5970 intersects with the other. */
5972 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5974 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
5978 /* Check the escaped solution if required.
5979 ??? Do we need to check the local against the IPA escaped sets? */
5980 if ((pt1->ipa_escaped || pt2->ipa_escaped)
5981 && !pt_solution_empty_p (&ipa_escaped_pt))
5983 /* If both point to escaped memory and that solution
5984 is not empty they alias. */
5985 if (pt1->ipa_escaped && pt2->ipa_escaped)
5988 /* If either points to escaped memory see if the escaped solution
5989 intersects with the other. */
5990 if ((pt1->ipa_escaped
5991 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
5992 || (pt2->ipa_escaped
5993 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
5997 /* Now both pointers alias if their points-to solution intersects. */
6000 && bitmap_intersect_p (pt1->vars, pt2->vars));
6004 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6006 bool res = pt_solutions_intersect_1 (pt1, pt2);
6008 ++pta_stats.pt_solutions_intersect_may_alias;
6010 ++pta_stats.pt_solutions_intersect_no_alias;
6014 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6015 qualified pointers are possibly based on the same pointer. */
6018 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6019 struct pt_solution *pt2)
6021 /* If we deal with points-to solutions of two restrict qualified
6022 pointers solely rely on the pointed-to variable bitmap intersection.
6023 For two pointers that are based on each other the bitmaps will
6025 if (pt1->vars_contains_restrict
6026 && pt2->vars_contains_restrict)
6028 gcc_assert (pt1->vars && pt2->vars);
6029 return bitmap_intersect_p (pt1->vars, pt2->vars);
6036 /* Dump points-to information to OUTFILE. */
6039 dump_sa_points_to_info (FILE *outfile)
6043 fprintf (outfile, "\nPoints-to sets\n\n");
6045 if (dump_flags & TDF_STATS)
6047 fprintf (outfile, "Stats:\n");
6048 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6049 fprintf (outfile, "Non-pointer vars: %d\n",
6050 stats.nonpointer_vars);
6051 fprintf (outfile, "Statically unified vars: %d\n",
6052 stats.unified_vars_static);
6053 fprintf (outfile, "Dynamically unified vars: %d\n",
6054 stats.unified_vars_dynamic);
6055 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6056 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6057 fprintf (outfile, "Number of implicit edges: %d\n",
6058 stats.num_implicit_edges);
6061 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6063 varinfo_t vi = get_varinfo (i);
6064 if (!vi->may_have_pointers)
6066 dump_solution_for_var (outfile, i);
6071 /* Debug points-to information to stderr. */
6074 debug_sa_points_to_info (void)
6076 dump_sa_points_to_info (stderr);
6080 /* Initialize the always-existing constraint variables for NULL
6081 ANYTHING, READONLY, and INTEGER */
6084 init_base_vars (void)
6086 struct constraint_expr lhs, rhs;
6087 varinfo_t var_anything;
6088 varinfo_t var_nothing;
6089 varinfo_t var_readonly;
6090 varinfo_t var_escaped;
6091 varinfo_t var_nonlocal;
6092 varinfo_t var_storedanything;
6093 varinfo_t var_integer;
6095 /* Create the NULL variable, used to represent that a variable points
6097 var_nothing = new_var_info (NULL_TREE, "NULL");
6098 gcc_assert (var_nothing->id == nothing_id);
6099 var_nothing->is_artificial_var = 1;
6100 var_nothing->offset = 0;
6101 var_nothing->size = ~0;
6102 var_nothing->fullsize = ~0;
6103 var_nothing->is_special_var = 1;
6104 var_nothing->may_have_pointers = 0;
6105 var_nothing->is_global_var = 0;
6107 /* Create the ANYTHING variable, used to represent that a variable
6108 points to some unknown piece of memory. */
6109 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6110 gcc_assert (var_anything->id == anything_id);
6111 var_anything->is_artificial_var = 1;
6112 var_anything->size = ~0;
6113 var_anything->offset = 0;
6114 var_anything->next = NULL;
6115 var_anything->fullsize = ~0;
6116 var_anything->is_special_var = 1;
6118 /* Anything points to anything. This makes deref constraints just
6119 work in the presence of linked list and other p = *p type loops,
6120 by saying that *ANYTHING = ANYTHING. */
6122 lhs.var = anything_id;
6124 rhs.type = ADDRESSOF;
6125 rhs.var = anything_id;
6128 /* This specifically does not use process_constraint because
6129 process_constraint ignores all anything = anything constraints, since all
6130 but this one are redundant. */
6131 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6133 /* Create the READONLY variable, used to represent that a variable
6134 points to readonly memory. */
6135 var_readonly = new_var_info (NULL_TREE, "READONLY");
6136 gcc_assert (var_readonly->id == readonly_id);
6137 var_readonly->is_artificial_var = 1;
6138 var_readonly->offset = 0;
6139 var_readonly->size = ~0;
6140 var_readonly->fullsize = ~0;
6141 var_readonly->next = NULL;
6142 var_readonly->is_special_var = 1;
6144 /* readonly memory points to anything, in order to make deref
6145 easier. In reality, it points to anything the particular
6146 readonly variable can point to, but we don't track this
6149 lhs.var = readonly_id;
6151 rhs.type = ADDRESSOF;
6152 rhs.var = readonly_id; /* FIXME */
6154 process_constraint (new_constraint (lhs, rhs));
6156 /* Create the ESCAPED variable, used to represent the set of escaped
6158 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6159 gcc_assert (var_escaped->id == escaped_id);
6160 var_escaped->is_artificial_var = 1;
6161 var_escaped->offset = 0;
6162 var_escaped->size = ~0;
6163 var_escaped->fullsize = ~0;
6164 var_escaped->is_special_var = 0;
6166 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6168 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6169 gcc_assert (var_nonlocal->id == nonlocal_id);
6170 var_nonlocal->is_artificial_var = 1;
6171 var_nonlocal->offset = 0;
6172 var_nonlocal->size = ~0;
6173 var_nonlocal->fullsize = ~0;
6174 var_nonlocal->is_special_var = 1;
6176 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6178 lhs.var = escaped_id;
6181 rhs.var = escaped_id;
6183 process_constraint (new_constraint (lhs, rhs));
6185 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6186 whole variable escapes. */
6188 lhs.var = escaped_id;
6191 rhs.var = escaped_id;
6192 rhs.offset = UNKNOWN_OFFSET;
6193 process_constraint (new_constraint (lhs, rhs));
6195 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6196 everything pointed to by escaped points to what global memory can
6199 lhs.var = escaped_id;
6202 rhs.var = nonlocal_id;
6204 process_constraint (new_constraint (lhs, rhs));
6206 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6207 global memory may point to global memory and escaped memory. */
6209 lhs.var = nonlocal_id;
6211 rhs.type = ADDRESSOF;
6212 rhs.var = nonlocal_id;
6214 process_constraint (new_constraint (lhs, rhs));
6215 rhs.type = ADDRESSOF;
6216 rhs.var = escaped_id;
6218 process_constraint (new_constraint (lhs, rhs));
6220 /* Create the STOREDANYTHING variable, used to represent the set of
6221 variables stored to *ANYTHING. */
6222 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6223 gcc_assert (var_storedanything->id == storedanything_id);
6224 var_storedanything->is_artificial_var = 1;
6225 var_storedanything->offset = 0;
6226 var_storedanything->size = ~0;
6227 var_storedanything->fullsize = ~0;
6228 var_storedanything->is_special_var = 0;
6230 /* Create the INTEGER variable, used to represent that a variable points
6231 to what an INTEGER "points to". */
6232 var_integer = new_var_info (NULL_TREE, "INTEGER");
6233 gcc_assert (var_integer->id == integer_id);
6234 var_integer->is_artificial_var = 1;
6235 var_integer->size = ~0;
6236 var_integer->fullsize = ~0;
6237 var_integer->offset = 0;
6238 var_integer->next = NULL;
6239 var_integer->is_special_var = 1;
6241 /* INTEGER = ANYTHING, because we don't know where a dereference of
6242 a random integer will point to. */
6244 lhs.var = integer_id;
6246 rhs.type = ADDRESSOF;
6247 rhs.var = anything_id;
6249 process_constraint (new_constraint (lhs, rhs));
6252 /* Initialize things necessary to perform PTA */
6255 init_alias_vars (void)
6257 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6259 bitmap_obstack_initialize (&pta_obstack);
6260 bitmap_obstack_initialize (&oldpta_obstack);
6261 bitmap_obstack_initialize (&predbitmap_obstack);
6263 constraint_pool = create_alloc_pool ("Constraint pool",
6264 sizeof (struct constraint), 30);
6265 variable_info_pool = create_alloc_pool ("Variable info pool",
6266 sizeof (struct variable_info), 30);
6267 constraints = VEC_alloc (constraint_t, heap, 8);
6268 varmap = VEC_alloc (varinfo_t, heap, 8);
6269 vi_for_tree = pointer_map_create ();
6270 call_stmt_vars = pointer_map_create ();
6272 memset (&stats, 0, sizeof (stats));
6273 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6274 shared_bitmap_eq, free);
6278 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6279 predecessor edges. */
6282 remove_preds_and_fake_succs (constraint_graph_t graph)
6286 /* Clear the implicit ref and address nodes from the successor
6288 for (i = 0; i < FIRST_REF_NODE; i++)
6290 if (graph->succs[i])
6291 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6292 FIRST_REF_NODE * 2);
6295 /* Free the successor list for the non-ref nodes. */
6296 for (i = FIRST_REF_NODE; i < graph->size; i++)
6298 if (graph->succs[i])
6299 BITMAP_FREE (graph->succs[i]);
6302 /* Now reallocate the size of the successor list as, and blow away
6303 the predecessor bitmaps. */
6304 graph->size = VEC_length (varinfo_t, varmap);
6305 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6307 free (graph->implicit_preds);
6308 graph->implicit_preds = NULL;
6309 free (graph->preds);
6310 graph->preds = NULL;
6311 bitmap_obstack_release (&predbitmap_obstack);
6314 /* Initialize the heapvar for statement mapping. */
6317 init_alias_heapvars (void)
6319 if (!heapvar_for_stmt)
6320 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6324 /* Delete the heapvar for statement mapping. */
6327 delete_alias_heapvars (void)
6329 if (heapvar_for_stmt)
6330 htab_delete (heapvar_for_stmt);
6331 heapvar_for_stmt = NULL;
6334 /* Solve the constraint set. */
6337 solve_constraints (void)
6339 struct scc_info *si;
6343 "\nCollapsing static cycles and doing variable "
6346 init_graph (VEC_length (varinfo_t, varmap) * 2);
6349 fprintf (dump_file, "Building predecessor graph\n");
6350 build_pred_graph ();
6353 fprintf (dump_file, "Detecting pointer and location "
6355 si = perform_var_substitution (graph);
6358 fprintf (dump_file, "Rewriting constraints and unifying "
6360 rewrite_constraints (graph, si);
6362 build_succ_graph ();
6363 free_var_substitution_info (si);
6365 if (dump_file && (dump_flags & TDF_GRAPH))
6366 dump_constraint_graph (dump_file);
6368 move_complex_constraints (graph);
6371 fprintf (dump_file, "Uniting pointer but not location equivalent "
6373 unite_pointer_equivalences (graph);
6376 fprintf (dump_file, "Finding indirect cycles\n");
6377 find_indirect_cycles (graph);
6379 /* Implicit nodes and predecessors are no longer necessary at this
6381 remove_preds_and_fake_succs (graph);
6384 fprintf (dump_file, "Solving graph\n");
6386 solve_graph (graph);
6389 dump_sa_points_to_info (dump_file);
6392 /* Create points-to sets for the current function. See the comments
6393 at the start of the file for an algorithmic overview. */
6396 compute_points_to_sets (void)
6402 timevar_push (TV_TREE_PTA);
6405 init_alias_heapvars ();
6407 intra_create_variable_infos ();
6409 /* Now walk all statements and build the constraint set. */
6412 gimple_stmt_iterator gsi;
6414 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6416 gimple phi = gsi_stmt (gsi);
6418 if (is_gimple_reg (gimple_phi_result (phi)))
6419 find_func_aliases (phi);
6422 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6424 gimple stmt = gsi_stmt (gsi);
6426 find_func_aliases (stmt);
6432 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6433 dump_constraints (dump_file, 0);
6436 /* From the constraints compute the points-to sets. */
6437 solve_constraints ();
6439 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6440 find_what_var_points_to (get_varinfo (escaped_id),
6441 &cfun->gimple_df->escaped);
6443 /* Make sure the ESCAPED solution (which is used as placeholder in
6444 other solutions) does not reference itself. This simplifies
6445 points-to solution queries. */
6446 cfun->gimple_df->escaped.escaped = 0;
6448 /* Mark escaped HEAP variables as global. */
6449 for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); ++i)
6451 && !vi->is_restrict_var
6452 && !vi->is_global_var)
6453 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6454 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6456 /* Compute the points-to sets for pointer SSA_NAMEs. */
6457 for (i = 0; i < num_ssa_names; ++i)
6459 tree ptr = ssa_name (i);
6461 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6462 find_what_p_points_to (ptr);
6465 /* Compute the call-used/clobbered sets. */
6468 gimple_stmt_iterator gsi;
6470 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6472 gimple stmt = gsi_stmt (gsi);
6473 struct pt_solution *pt;
6474 if (!is_gimple_call (stmt))
6477 pt = gimple_call_use_set (stmt);
6478 if (gimple_call_flags (stmt) & ECF_CONST)
6479 memset (pt, 0, sizeof (struct pt_solution));
6480 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6482 find_what_var_points_to (vi, pt);
6483 /* Escaped (and thus nonlocal) variables are always
6484 implicitly used by calls. */
6485 /* ??? ESCAPED can be empty even though NONLOCAL
6492 /* If there is nothing special about this call then
6493 we have made everything that is used also escape. */
6494 *pt = cfun->gimple_df->escaped;
6498 pt = gimple_call_clobber_set (stmt);
6499 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6500 memset (pt, 0, sizeof (struct pt_solution));
6501 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6503 find_what_var_points_to (vi, pt);
6504 /* Escaped (and thus nonlocal) variables are always
6505 implicitly clobbered by calls. */
6506 /* ??? ESCAPED can be empty even though NONLOCAL
6513 /* If there is nothing special about this call then
6514 we have made everything that is used also escape. */
6515 *pt = cfun->gimple_df->escaped;
6521 timevar_pop (TV_TREE_PTA);
6525 /* Delete created points-to sets. */
6528 delete_points_to_sets (void)
6532 htab_delete (shared_bitmap_table);
6533 if (dump_file && (dump_flags & TDF_STATS))
6534 fprintf (dump_file, "Points to sets created:%d\n",
6535 stats.points_to_sets_created);
6537 pointer_map_destroy (vi_for_tree);
6538 pointer_map_destroy (call_stmt_vars);
6539 bitmap_obstack_release (&pta_obstack);
6540 VEC_free (constraint_t, heap, constraints);
6542 for (i = 0; i < graph->size; i++)
6543 VEC_free (constraint_t, heap, graph->complex[i]);
6544 free (graph->complex);
6547 free (graph->succs);
6549 free (graph->pe_rep);
6550 free (graph->indirect_cycles);
6553 VEC_free (varinfo_t, heap, varmap);
6554 free_alloc_pool (variable_info_pool);
6555 free_alloc_pool (constraint_pool);
6559 /* Compute points-to information for every SSA_NAME pointer in the
6560 current function and compute the transitive closure of escaped
6561 variables to re-initialize the call-clobber states of local variables. */
6564 compute_may_aliases (void)
6566 if (cfun->gimple_df->ipa_pta)
6570 fprintf (dump_file, "\nNot re-computing points-to information "
6571 "because IPA points-to information is available.\n\n");
6573 /* But still dump what we have remaining it. */
6574 dump_alias_info (dump_file);
6576 if (dump_flags & TDF_DETAILS)
6577 dump_referenced_vars (dump_file);
6583 /* For each pointer P_i, determine the sets of variables that P_i may
6584 point-to. Compute the reachability set of escaped and call-used
6586 compute_points_to_sets ();
6588 /* Debugging dumps. */
6591 dump_alias_info (dump_file);
6593 if (dump_flags & TDF_DETAILS)
6594 dump_referenced_vars (dump_file);
6597 /* Deallocate memory used by aliasing data structures and the internal
6598 points-to solution. */
6599 delete_points_to_sets ();
6601 gcc_assert (!need_ssa_update_p (cfun));
6607 gate_tree_pta (void)
6609 return flag_tree_pta;
6612 /* A dummy pass to cause points-to information to be computed via
6613 TODO_rebuild_alias. */
6615 struct gimple_opt_pass pass_build_alias =
6620 gate_tree_pta, /* gate */
6624 0, /* static_pass_number */
6625 TV_NONE, /* tv_id */
6626 PROP_cfg | PROP_ssa, /* properties_required */
6627 0, /* properties_provided */
6628 0, /* properties_destroyed */
6629 0, /* todo_flags_start */
6630 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6634 /* A dummy pass to cause points-to information to be computed via
6635 TODO_rebuild_alias. */
6637 struct gimple_opt_pass pass_build_ealias =
6641 "ealias", /* name */
6642 gate_tree_pta, /* gate */
6646 0, /* static_pass_number */
6647 TV_NONE, /* tv_id */
6648 PROP_cfg | PROP_ssa, /* properties_required */
6649 0, /* properties_provided */
6650 0, /* properties_destroyed */
6651 0, /* todo_flags_start */
6652 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6657 /* Return true if we should execute IPA PTA. */
6663 /* Don't bother doing anything if the program has errors. */
6667 /* IPA PTA solutions for ESCAPED. */
6668 struct pt_solution ipa_escaped_pt
6669 = { true, false, false, false, false, false, false, NULL };
6671 /* Execute the driver for IPA PTA. */
6673 ipa_pta_execute (void)
6675 struct cgraph_node *node;
6676 struct varpool_node *var;
6681 init_alias_heapvars ();
6684 /* Build the constraints. */
6685 for (node = cgraph_nodes; node; node = node->next)
6687 struct cgraph_node *alias;
6690 /* Nodes without a body are not interesting. Especially do not
6691 visit clones at this point for now - we get duplicate decls
6692 there for inline clones at least. */
6693 if (!gimple_has_body_p (node->decl)
6697 vi = create_function_info_for (node->decl,
6698 alias_get_name (node->decl));
6700 /* Associate the varinfo node with all aliases. */
6701 for (alias = node->same_body; alias; alias = alias->next)
6702 insert_vi_for_tree (alias->decl, vi);
6705 /* Create constraints for global variables and their initializers. */
6706 for (var = varpool_nodes; var; var = var->next)
6708 struct varpool_node *alias;
6711 vi = get_vi_for_tree (var->decl);
6713 /* Associate the varinfo node with all aliases. */
6714 for (alias = var->extra_name; alias; alias = alias->next)
6715 insert_vi_for_tree (alias->decl, vi);
6721 "Generating constraints for global initializers\n\n");
6722 dump_constraints (dump_file, 0);
6723 fprintf (dump_file, "\n");
6725 from = VEC_length (constraint_t, constraints);
6727 for (node = cgraph_nodes; node; node = node->next)
6729 struct function *func;
6733 /* Nodes without a body are not interesting. */
6734 if (!gimple_has_body_p (node->decl)
6741 "Generating constraints for %s", cgraph_node_name (node));
6742 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6743 fprintf (dump_file, " (%s)",
6744 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6745 fprintf (dump_file, "\n");
6748 func = DECL_STRUCT_FUNCTION (node->decl);
6749 old_func_decl = current_function_decl;
6751 current_function_decl = node->decl;
6753 /* For externally visible functions use local constraints for
6754 their arguments. For local functions we see all callers
6755 and thus do not need initial constraints for parameters. */
6756 if (node->local.externally_visible)
6757 intra_create_variable_infos ();
6759 /* Build constriants for the function body. */
6760 FOR_EACH_BB_FN (bb, func)
6762 gimple_stmt_iterator gsi;
6764 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6767 gimple phi = gsi_stmt (gsi);
6769 if (is_gimple_reg (gimple_phi_result (phi)))
6770 find_func_aliases (phi);
6773 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6775 gimple stmt = gsi_stmt (gsi);
6777 find_func_aliases (stmt);
6778 find_func_clobbers (stmt);
6782 current_function_decl = old_func_decl;
6787 fprintf (dump_file, "\n");
6788 dump_constraints (dump_file, from);
6789 fprintf (dump_file, "\n");
6791 from = VEC_length (constraint_t, constraints);
6794 /* From the constraints compute the points-to sets. */
6795 solve_constraints ();
6797 /* Compute the global points-to sets for ESCAPED.
6798 ??? Note that the computed escape set is not correct
6799 for the whole unit as we fail to consider graph edges to
6800 externally visible functions. */
6801 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6803 /* Make sure the ESCAPED solution (which is used as placeholder in
6804 other solutions) does not reference itself. This simplifies
6805 points-to solution queries. */
6806 ipa_escaped_pt.ipa_escaped = 0;
6808 /* Assign the points-to sets to the SSA names in the unit. */
6809 for (node = cgraph_nodes; node; node = node->next)
6812 struct function *fn;
6816 struct pt_solution uses, clobbers;
6817 struct cgraph_edge *e;
6819 /* Nodes without a body are not interesting. */
6820 if (!gimple_has_body_p (node->decl)
6824 fn = DECL_STRUCT_FUNCTION (node->decl);
6826 /* Compute the points-to sets for pointer SSA_NAMEs. */
6827 for (i = 0; VEC_iterate (tree, fn->gimple_df->ssa_names, i, ptr); ++i)
6830 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6831 find_what_p_points_to (ptr);
6834 /* Compute the call-use and call-clobber sets for all direct calls. */
6835 fi = lookup_vi_for_tree (node->decl);
6836 gcc_assert (fi->is_fn_info);
6837 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6839 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6840 for (e = node->callers; e; e = e->next_caller)
6845 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6846 *gimple_call_use_set (e->call_stmt) = uses;
6849 /* Compute the call-use and call-clobber sets for indirect calls
6850 and calls to external functions. */
6851 FOR_EACH_BB_FN (bb, fn)
6853 gimple_stmt_iterator gsi;
6855 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6857 gimple stmt = gsi_stmt (gsi);
6858 struct pt_solution *pt;
6862 if (!is_gimple_call (stmt))
6865 /* Handle direct calls to external functions. */
6866 decl = gimple_call_fndecl (stmt);
6868 && (!(fi = lookup_vi_for_tree (decl))
6869 || !fi->is_fn_info))
6871 pt = gimple_call_use_set (stmt);
6872 if (gimple_call_flags (stmt) & ECF_CONST)
6873 memset (pt, 0, sizeof (struct pt_solution));
6874 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6876 find_what_var_points_to (vi, pt);
6877 /* Escaped (and thus nonlocal) variables are always
6878 implicitly used by calls. */
6879 /* ??? ESCAPED can be empty even though NONLOCAL
6882 pt->ipa_escaped = 1;
6886 /* If there is nothing special about this call then
6887 we have made everything that is used also escape. */
6888 *pt = ipa_escaped_pt;
6892 pt = gimple_call_clobber_set (stmt);
6893 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6894 memset (pt, 0, sizeof (struct pt_solution));
6895 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6897 find_what_var_points_to (vi, pt);
6898 /* Escaped (and thus nonlocal) variables are always
6899 implicitly clobbered by calls. */
6900 /* ??? ESCAPED can be empty even though NONLOCAL
6903 pt->ipa_escaped = 1;
6907 /* If there is nothing special about this call then
6908 we have made everything that is used also escape. */
6909 *pt = ipa_escaped_pt;
6914 /* Handle indirect calls. */
6916 && (fi = get_fi_for_callee (stmt)))
6918 /* We need to accumulate all clobbers/uses of all possible
6920 fi = get_varinfo (find (fi->id));
6921 /* If we cannot constrain the set of functions we'll end up
6922 calling we end up using/clobbering everything. */
6923 if (bitmap_bit_p (fi->solution, anything_id)
6924 || bitmap_bit_p (fi->solution, nonlocal_id)
6925 || bitmap_bit_p (fi->solution, escaped_id))
6927 pt_solution_reset (gimple_call_clobber_set (stmt));
6928 pt_solution_reset (gimple_call_use_set (stmt));
6934 struct pt_solution *uses, *clobbers;
6936 uses = gimple_call_use_set (stmt);
6937 clobbers = gimple_call_clobber_set (stmt);
6938 memset (uses, 0, sizeof (struct pt_solution));
6939 memset (clobbers, 0, sizeof (struct pt_solution));
6940 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6942 struct pt_solution sol;
6944 vi = get_varinfo (i);
6945 if (!vi->is_fn_info)
6947 /* ??? We could be more precise here? */
6949 uses->ipa_escaped = 1;
6950 clobbers->nonlocal = 1;
6951 clobbers->ipa_escaped = 1;
6955 if (!uses->anything)
6957 find_what_var_points_to
6958 (first_vi_for_offset (vi, fi_uses), &sol);
6959 pt_solution_ior_into (uses, &sol);
6961 if (!clobbers->anything)
6963 find_what_var_points_to
6964 (first_vi_for_offset (vi, fi_clobbers), &sol);
6965 pt_solution_ior_into (clobbers, &sol);
6973 fn->gimple_df->ipa_pta = true;
6976 delete_points_to_sets ();
6983 struct simple_ipa_opt_pass pass_ipa_pta =
6988 gate_ipa_pta, /* gate */
6989 ipa_pta_execute, /* execute */
6992 0, /* static_pass_number */
6993 TV_IPA_PTA, /* tv_id */
6994 0, /* properties_required */
6995 0, /* properties_provided */
6996 0, /* properties_destroyed */
6997 0, /* todo_flags_start */
6998 TODO_update_ssa /* todo_flags_finish */
7003 #include "gt-tree-ssa-structalias.h"