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 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2841 && SSA_NAME_IS_DEFAULT_DEF (t))
2843 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2847 vi = get_vi_for_tree (t);
2849 cexpr.type = SCALAR;
2851 /* If we determine the result is "anything", and we know this is readonly,
2852 say it points to readonly memory instead. */
2853 if (cexpr.var == anything_id && TREE_READONLY (t))
2856 cexpr.type = ADDRESSOF;
2857 cexpr.var = readonly_id;
2860 /* If we are not taking the address of the constraint expr, add all
2861 sub-fiels of the variable as well. */
2863 && !vi->is_full_var)
2865 for (; vi; vi = vi->next)
2868 VEC_safe_push (ce_s, heap, *results, &cexpr);
2873 VEC_safe_push (ce_s, heap, *results, &cexpr);
2876 /* Process constraint T, performing various simplifications and then
2877 adding it to our list of overall constraints. */
2880 process_constraint (constraint_t t)
2882 struct constraint_expr rhs = t->rhs;
2883 struct constraint_expr lhs = t->lhs;
2885 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2886 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2888 /* If we didn't get any useful constraint from the lhs we get
2889 &ANYTHING as fallback from get_constraint_for. Deal with
2890 it here by turning it into *ANYTHING. */
2891 if (lhs.type == ADDRESSOF
2892 && lhs.var == anything_id)
2895 /* ADDRESSOF on the lhs is invalid. */
2896 gcc_assert (lhs.type != ADDRESSOF);
2898 /* We shouldn't add constraints from things that cannot have pointers.
2899 It's not completely trivial to avoid in the callers, so do it here. */
2900 if (rhs.type != ADDRESSOF
2901 && !get_varinfo (rhs.var)->may_have_pointers)
2904 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2905 if (!get_varinfo (lhs.var)->may_have_pointers)
2908 /* This can happen in our IR with things like n->a = *p */
2909 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2911 /* Split into tmp = *rhs, *lhs = tmp */
2912 struct constraint_expr tmplhs;
2913 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2914 process_constraint (new_constraint (tmplhs, rhs));
2915 process_constraint (new_constraint (lhs, tmplhs));
2917 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2919 /* Split into tmp = &rhs, *lhs = tmp */
2920 struct constraint_expr tmplhs;
2921 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2922 process_constraint (new_constraint (tmplhs, rhs));
2923 process_constraint (new_constraint (lhs, tmplhs));
2927 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2928 VEC_safe_push (constraint_t, heap, constraints, t);
2932 /* Return true if T is a type that could contain pointers. */
2935 type_could_have_pointers (tree type)
2937 if (POINTER_TYPE_P (type))
2940 if (TREE_CODE (type) == ARRAY_TYPE)
2941 return type_could_have_pointers (TREE_TYPE (type));
2943 /* A function or method can consume pointers.
2944 ??? We could be more precise here. */
2945 if (TREE_CODE (type) == FUNCTION_TYPE
2946 || TREE_CODE (type) == METHOD_TYPE)
2949 return AGGREGATE_TYPE_P (type);
2952 /* Return true if T is a variable of a type that could contain
2956 could_have_pointers (tree t)
2958 return (((TREE_CODE (t) == VAR_DECL
2959 || TREE_CODE (t) == PARM_DECL
2960 || TREE_CODE (t) == RESULT_DECL)
2961 && (TREE_PUBLIC (t) || DECL_EXTERNAL (t) || TREE_ADDRESSABLE (t)))
2962 || type_could_have_pointers (TREE_TYPE (t)));
2965 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2968 static HOST_WIDE_INT
2969 bitpos_of_field (const tree fdecl)
2972 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2973 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2976 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2977 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2981 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2982 resulting constraint expressions in *RESULTS. */
2985 get_constraint_for_ptr_offset (tree ptr, tree offset,
2986 VEC (ce_s, heap) **results)
2988 struct constraint_expr c;
2990 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2992 /* If we do not do field-sensitive PTA adding offsets to pointers
2993 does not change the points-to solution. */
2994 if (!use_field_sensitive)
2996 get_constraint_for (ptr, results);
3000 /* If the offset is not a non-negative integer constant that fits
3001 in a HOST_WIDE_INT, we have to fall back to a conservative
3002 solution which includes all sub-fields of all pointed-to
3003 variables of ptr. */
3004 if (offset == NULL_TREE
3005 || !host_integerp (offset, 0))
3006 rhsoffset = UNKNOWN_OFFSET;
3009 /* Make sure the bit-offset also fits. */
3010 rhsunitoffset = TREE_INT_CST_LOW (offset);
3011 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
3012 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
3013 rhsoffset = UNKNOWN_OFFSET;
3016 get_constraint_for (ptr, results);
3020 /* As we are eventually appending to the solution do not use
3021 VEC_iterate here. */
3022 n = VEC_length (ce_s, *results);
3023 for (j = 0; j < n; j++)
3026 c = *VEC_index (ce_s, *results, j);
3027 curr = get_varinfo (c.var);
3029 if (c.type == ADDRESSOF
3030 /* If this varinfo represents a full variable just use it. */
3031 && curr->is_full_var)
3033 else if (c.type == ADDRESSOF
3034 /* If we do not know the offset add all subfields. */
3035 && rhsoffset == UNKNOWN_OFFSET)
3037 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3040 struct constraint_expr c2;
3042 c2.type = ADDRESSOF;
3044 if (c2.var != c.var)
3045 VEC_safe_push (ce_s, heap, *results, &c2);
3050 else if (c.type == ADDRESSOF)
3053 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3055 /* Search the sub-field which overlaps with the
3056 pointed-to offset. If the result is outside of the variable
3057 we have to provide a conservative result, as the variable is
3058 still reachable from the resulting pointer (even though it
3059 technically cannot point to anything). The last and first
3060 sub-fields are such conservative results.
3061 ??? If we always had a sub-field for &object + 1 then
3062 we could represent this in a more precise way. */
3064 && curr->offset < offset)
3066 temp = first_or_preceding_vi_for_offset (curr, offset);
3068 /* If the found variable is not exactly at the pointed to
3069 result, we have to include the next variable in the
3070 solution as well. Otherwise two increments by offset / 2
3071 do not result in the same or a conservative superset
3073 if (temp->offset != offset
3074 && temp->next != NULL)
3076 struct constraint_expr c2;
3077 c2.var = temp->next->id;
3078 c2.type = ADDRESSOF;
3080 VEC_safe_push (ce_s, heap, *results, &c2);
3086 c.offset = rhsoffset;
3088 VEC_replace (ce_s, *results, j, &c);
3093 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3094 If address_p is true the result will be taken its address of. */
3097 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3101 HOST_WIDE_INT bitsize = -1;
3102 HOST_WIDE_INT bitmaxsize = -1;
3103 HOST_WIDE_INT bitpos;
3105 struct constraint_expr *result;
3107 /* Some people like to do cute things like take the address of
3110 while (handled_component_p (forzero)
3111 || INDIRECT_REF_P (forzero)
3112 || TREE_CODE (forzero) == MEM_REF)
3113 forzero = TREE_OPERAND (forzero, 0);
3115 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3117 struct constraint_expr temp;
3120 temp.var = integer_id;
3122 VEC_safe_push (ce_s, heap, *results, &temp);
3126 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3128 /* Pretend to take the address of the base, we'll take care of
3129 adding the required subset of sub-fields below. */
3130 get_constraint_for_1 (t, results, true);
3131 gcc_assert (VEC_length (ce_s, *results) == 1);
3132 result = VEC_last (ce_s, *results);
3134 if (result->type == SCALAR
3135 && get_varinfo (result->var)->is_full_var)
3136 /* For single-field vars do not bother about the offset. */
3138 else if (result->type == SCALAR)
3140 /* In languages like C, you can access one past the end of an
3141 array. You aren't allowed to dereference it, so we can
3142 ignore this constraint. When we handle pointer subtraction,
3143 we may have to do something cute here. */
3145 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3148 /* It's also not true that the constraint will actually start at the
3149 right offset, it may start in some padding. We only care about
3150 setting the constraint to the first actual field it touches, so
3152 struct constraint_expr cexpr = *result;
3154 VEC_pop (ce_s, *results);
3156 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3158 if (ranges_overlap_p (curr->offset, curr->size,
3159 bitpos, bitmaxsize))
3161 cexpr.var = curr->id;
3162 VEC_safe_push (ce_s, heap, *results, &cexpr);
3167 /* If we are going to take the address of this field then
3168 to be able to compute reachability correctly add at least
3169 the last field of the variable. */
3171 && VEC_length (ce_s, *results) == 0)
3173 curr = get_varinfo (cexpr.var);
3174 while (curr->next != NULL)
3176 cexpr.var = curr->id;
3177 VEC_safe_push (ce_s, heap, *results, &cexpr);
3180 /* Assert that we found *some* field there. The user couldn't be
3181 accessing *only* padding. */
3182 /* Still the user could access one past the end of an array
3183 embedded in a struct resulting in accessing *only* padding. */
3184 gcc_assert (VEC_length (ce_s, *results) >= 1
3185 || ref_contains_array_ref (orig_t));
3187 else if (bitmaxsize == 0)
3189 if (dump_file && (dump_flags & TDF_DETAILS))
3190 fprintf (dump_file, "Access to zero-sized part of variable,"
3194 if (dump_file && (dump_flags & TDF_DETAILS))
3195 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3197 else if (result->type == DEREF)
3199 /* If we do not know exactly where the access goes say so. Note
3200 that only for non-structure accesses we know that we access
3201 at most one subfiled of any variable. */
3203 || bitsize != bitmaxsize
3204 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3205 result->offset = UNKNOWN_OFFSET;
3207 result->offset = bitpos;
3209 else if (result->type == ADDRESSOF)
3211 /* We can end up here for component references on a
3212 VIEW_CONVERT_EXPR <>(&foobar). */
3213 result->type = SCALAR;
3214 result->var = anything_id;
3222 /* Dereference the constraint expression CONS, and return the result.
3223 DEREF (ADDRESSOF) = SCALAR
3224 DEREF (SCALAR) = DEREF
3225 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3226 This is needed so that we can handle dereferencing DEREF constraints. */
3229 do_deref (VEC (ce_s, heap) **constraints)
3231 struct constraint_expr *c;
3234 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3236 if (c->type == SCALAR)
3238 else if (c->type == ADDRESSOF)
3240 else if (c->type == DEREF)
3242 struct constraint_expr tmplhs;
3243 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3244 process_constraint (new_constraint (tmplhs, *c));
3245 c->var = tmplhs.var;
3252 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3254 /* Given a tree T, return the constraint expression for taking the
3258 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3260 struct constraint_expr *c;
3263 get_constraint_for_1 (t, results, true);
3265 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3267 if (c->type == DEREF)
3270 c->type = ADDRESSOF;
3274 /* Given a tree T, return the constraint expression for it. */
3277 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3279 struct constraint_expr temp;
3281 /* x = integer is all glommed to a single variable, which doesn't
3282 point to anything by itself. That is, of course, unless it is an
3283 integer constant being treated as a pointer, in which case, we
3284 will return that this is really the addressof anything. This
3285 happens below, since it will fall into the default case. The only
3286 case we know something about an integer treated like a pointer is
3287 when it is the NULL pointer, and then we just say it points to
3290 Do not do that if -fno-delete-null-pointer-checks though, because
3291 in that case *NULL does not fail, so it _should_ alias *anything.
3292 It is not worth adding a new option or renaming the existing one,
3293 since this case is relatively obscure. */
3294 if ((TREE_CODE (t) == INTEGER_CST
3295 && integer_zerop (t))
3296 /* The only valid CONSTRUCTORs in gimple with pointer typed
3297 elements are zero-initializer. But in IPA mode we also
3298 process global initializers, so verify at least. */
3299 || (TREE_CODE (t) == CONSTRUCTOR
3300 && CONSTRUCTOR_NELTS (t) == 0))
3302 if (flag_delete_null_pointer_checks)
3303 temp.var = nothing_id;
3305 temp.var = anything_id;
3306 temp.type = ADDRESSOF;
3308 VEC_safe_push (ce_s, heap, *results, &temp);
3312 /* String constants are read-only. */
3313 if (TREE_CODE (t) == STRING_CST)
3315 temp.var = readonly_id;
3318 VEC_safe_push (ce_s, heap, *results, &temp);
3322 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3324 case tcc_expression:
3326 switch (TREE_CODE (t))
3329 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3337 switch (TREE_CODE (t))
3341 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
3342 TREE_OPERAND (t, 1), results);
3347 case ARRAY_RANGE_REF:
3349 get_constraint_for_component_ref (t, results, address_p);
3351 case VIEW_CONVERT_EXPR:
3352 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3354 /* We are missing handling for TARGET_MEM_REF here. */
3359 case tcc_exceptional:
3361 switch (TREE_CODE (t))
3365 get_constraint_for_ssa_var (t, results, address_p);
3372 VEC (ce_s, heap) *tmp = NULL;
3373 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3375 struct constraint_expr *rhsp;
3377 get_constraint_for_1 (val, &tmp, address_p);
3378 for (j = 0; VEC_iterate (ce_s, tmp, j, rhsp); ++j)
3379 VEC_safe_push (ce_s, heap, *results, rhsp);
3380 VEC_truncate (ce_s, tmp, 0);
3382 VEC_free (ce_s, heap, tmp);
3383 /* We do not know whether the constructor was complete,
3384 so technically we have to add &NOTHING or &ANYTHING
3385 like we do for an empty constructor as well. */
3392 case tcc_declaration:
3394 get_constraint_for_ssa_var (t, results, address_p);
3400 /* The default fallback is a constraint from anything. */
3401 temp.type = ADDRESSOF;
3402 temp.var = anything_id;
3404 VEC_safe_push (ce_s, heap, *results, &temp);
3407 /* Given a gimple tree T, return the constraint expression vector for it. */
3410 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3412 gcc_assert (VEC_length (ce_s, *results) == 0);
3414 get_constraint_for_1 (t, results, false);
3418 /* Efficiently generates constraints from all entries in *RHSC to all
3419 entries in *LHSC. */
3422 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3424 struct constraint_expr *lhsp, *rhsp;
3427 if (VEC_length (ce_s, lhsc) <= 1
3428 || VEC_length (ce_s, rhsc) <= 1)
3430 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3431 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3432 process_constraint (new_constraint (*lhsp, *rhsp));
3436 struct constraint_expr tmp;
3437 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3438 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3439 process_constraint (new_constraint (tmp, *rhsp));
3440 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3441 process_constraint (new_constraint (*lhsp, tmp));
3445 /* Handle aggregate copies by expanding into copies of the respective
3446 fields of the structures. */
3449 do_structure_copy (tree lhsop, tree rhsop)
3451 struct constraint_expr *lhsp, *rhsp;
3452 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3455 get_constraint_for (lhsop, &lhsc);
3456 get_constraint_for (rhsop, &rhsc);
3457 lhsp = VEC_index (ce_s, lhsc, 0);
3458 rhsp = VEC_index (ce_s, rhsc, 0);
3459 if (lhsp->type == DEREF
3460 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3461 || rhsp->type == DEREF)
3463 if (lhsp->type == DEREF)
3465 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3466 lhsp->offset = UNKNOWN_OFFSET;
3468 if (rhsp->type == DEREF)
3470 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3471 rhsp->offset = UNKNOWN_OFFSET;
3473 process_all_all_constraints (lhsc, rhsc);
3475 else if (lhsp->type == SCALAR
3476 && (rhsp->type == SCALAR
3477 || rhsp->type == ADDRESSOF))
3479 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3480 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3482 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3483 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3484 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3486 varinfo_t lhsv, rhsv;
3487 rhsp = VEC_index (ce_s, rhsc, k);
3488 lhsv = get_varinfo (lhsp->var);
3489 rhsv = get_varinfo (rhsp->var);
3490 if (lhsv->may_have_pointers
3491 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3492 rhsv->offset + lhsoffset, rhsv->size))
3493 process_constraint (new_constraint (*lhsp, *rhsp));
3494 if (lhsv->offset + rhsoffset + lhsv->size
3495 > rhsv->offset + lhsoffset + rhsv->size)
3498 if (k >= VEC_length (ce_s, rhsc))
3508 VEC_free (ce_s, heap, lhsc);
3509 VEC_free (ce_s, heap, rhsc);
3512 /* Create a constraint ID = OP. */
3515 make_constraint_to (unsigned id, tree op)
3517 VEC(ce_s, heap) *rhsc = NULL;
3518 struct constraint_expr *c;
3519 struct constraint_expr includes;
3523 includes.offset = 0;
3524 includes.type = SCALAR;
3526 get_constraint_for (op, &rhsc);
3527 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3528 process_constraint (new_constraint (includes, *c));
3529 VEC_free (ce_s, heap, rhsc);
3532 /* Create a constraint ID = &FROM. */
3535 make_constraint_from (varinfo_t vi, int from)
3537 struct constraint_expr lhs, rhs;
3545 rhs.type = ADDRESSOF;
3546 process_constraint (new_constraint (lhs, rhs));
3549 /* Create a constraint ID = FROM. */
3552 make_copy_constraint (varinfo_t vi, int from)
3554 struct constraint_expr lhs, rhs;
3563 process_constraint (new_constraint (lhs, rhs));
3566 /* Make constraints necessary to make OP escape. */
3569 make_escape_constraint (tree op)
3571 make_constraint_to (escaped_id, op);
3574 /* Add constraints to that the solution of VI is transitively closed. */
3577 make_transitive_closure_constraints (varinfo_t vi)
3579 struct constraint_expr lhs, rhs;
3588 process_constraint (new_constraint (lhs, rhs));
3590 /* VAR = VAR + UNKNOWN; */
3596 rhs.offset = UNKNOWN_OFFSET;
3597 process_constraint (new_constraint (lhs, rhs));
3600 /* Create a new artificial heap variable with NAME.
3601 Return the created variable. */
3604 make_heapvar_for (varinfo_t lhs, const char *name)
3607 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3609 if (heapvar == NULL_TREE)
3612 heapvar = create_tmp_var_raw (ptr_type_node, name);
3613 DECL_EXTERNAL (heapvar) = 1;
3615 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3617 ann = get_var_ann (heapvar);
3618 ann->is_heapvar = 1;
3621 /* For global vars we need to add a heapvar to the list of referenced
3622 vars of a different function than it was created for originally. */
3623 if (cfun && gimple_referenced_vars (cfun))
3624 add_referenced_var (heapvar);
3626 vi = new_var_info (heapvar, name);
3627 vi->is_artificial_var = true;
3628 vi->is_heap_var = true;
3629 vi->is_unknown_size_var = true;
3633 vi->is_full_var = true;
3634 insert_vi_for_tree (heapvar, vi);
3639 /* Create a new artificial heap variable with NAME and make a
3640 constraint from it to LHS. Return the created variable. */
3643 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3645 varinfo_t vi = make_heapvar_for (lhs, name);
3646 make_constraint_from (lhs, vi->id);
3651 /* Create a new artificial heap variable with NAME and make a
3652 constraint from it to LHS. Set flags according to a tag used
3653 for tracking restrict pointers. */
3656 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3659 vi = make_constraint_from_heapvar (lhs, name);
3660 vi->is_restrict_var = 1;
3661 vi->is_global_var = 0;
3662 vi->is_special_var = 1;
3663 vi->may_have_pointers = 0;
3666 /* In IPA mode there are varinfos for different aspects of reach
3667 function designator. One for the points-to set of the return
3668 value, one for the variables that are clobbered by the function,
3669 one for its uses and one for each parameter (including a single
3670 glob for remaining variadic arguments). */
3672 enum { fi_clobbers = 1, fi_uses = 2,
3673 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3675 /* Get a constraint for the requested part of a function designator FI
3676 when operating in IPA mode. */
3678 static struct constraint_expr
3679 get_function_part_constraint (varinfo_t fi, unsigned part)
3681 struct constraint_expr c;
3683 gcc_assert (in_ipa_mode);
3685 if (fi->id == anything_id)
3687 /* ??? We probably should have a ANYFN special variable. */
3688 c.var = anything_id;
3692 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3694 varinfo_t ai = first_vi_for_offset (fi, part);
3698 c.var = anything_id;
3712 /* For non-IPA mode, generate constraints necessary for a call on the
3716 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3718 struct constraint_expr rhsc;
3720 bool returns_uses = false;
3722 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3724 tree arg = gimple_call_arg (stmt, i);
3725 int flags = gimple_call_arg_flags (stmt, i);
3727 /* If the argument is not used or it does not contain pointers
3728 we can ignore it. */
3729 if ((flags & EAF_UNUSED)
3730 || !could_have_pointers (arg))
3733 /* As we compute ESCAPED context-insensitive we do not gain
3734 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3735 set. The argument would still get clobbered through the
3737 ??? We might get away with less (and more precise) constraints
3738 if using a temporary for transitively closing things. */
3739 if ((flags & EAF_NOCLOBBER)
3740 && (flags & EAF_NOESCAPE))
3742 varinfo_t uses = get_call_use_vi (stmt);
3743 if (!(flags & EAF_DIRECT))
3744 make_transitive_closure_constraints (uses);
3745 make_constraint_to (uses->id, arg);
3746 returns_uses = true;
3748 else if (flags & EAF_NOESCAPE)
3750 varinfo_t uses = get_call_use_vi (stmt);
3751 varinfo_t clobbers = get_call_clobber_vi (stmt);
3752 if (!(flags & EAF_DIRECT))
3754 make_transitive_closure_constraints (uses);
3755 make_transitive_closure_constraints (clobbers);
3757 make_constraint_to (uses->id, arg);
3758 make_constraint_to (clobbers->id, arg);
3759 returns_uses = true;
3762 make_escape_constraint (arg);
3765 /* If we added to the calls uses solution make sure we account for
3766 pointers to it to be returned. */
3769 rhsc.var = get_call_use_vi (stmt)->id;
3772 VEC_safe_push (ce_s, heap, *results, &rhsc);
3775 /* The static chain escapes as well. */
3776 if (gimple_call_chain (stmt))
3777 make_escape_constraint (gimple_call_chain (stmt));
3779 /* And if we applied NRV the address of the return slot escapes as well. */
3780 if (gimple_call_return_slot_opt_p (stmt)
3781 && gimple_call_lhs (stmt) != NULL_TREE
3782 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3784 VEC(ce_s, heap) *tmpc = NULL;
3785 struct constraint_expr lhsc, *c;
3786 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3787 lhsc.var = escaped_id;
3790 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3791 process_constraint (new_constraint (lhsc, *c));
3792 VEC_free(ce_s, heap, tmpc);
3795 /* Regular functions return nonlocal memory. */
3796 rhsc.var = nonlocal_id;
3799 VEC_safe_push (ce_s, heap, *results, &rhsc);
3802 /* For non-IPA mode, generate constraints necessary for a call
3803 that returns a pointer and assigns it to LHS. This simply makes
3804 the LHS point to global and escaped variables. */
3807 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3810 VEC(ce_s, heap) *lhsc = NULL;
3812 get_constraint_for (lhs, &lhsc);
3813 /* If the store is to a global decl make sure to
3814 add proper escape constraints. */
3815 lhs = get_base_address (lhs);
3818 && is_global_var (lhs))
3820 struct constraint_expr tmpc;
3821 tmpc.var = escaped_id;
3824 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3827 /* If the call returns an argument unmodified override the rhs
3829 flags = gimple_call_return_flags (stmt);
3830 if (flags & ERF_RETURNS_ARG
3831 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3835 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3836 get_constraint_for (arg, &rhsc);
3837 process_all_all_constraints (lhsc, rhsc);
3838 VEC_free (ce_s, heap, rhsc);
3840 else if (flags & ERF_NOALIAS)
3843 struct constraint_expr tmpc;
3845 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3846 /* We delay marking allocated storage global until we know if
3848 DECL_EXTERNAL (vi->decl) = 0;
3849 vi->is_global_var = 0;
3850 /* If this is not a real malloc call assume the memory was
3851 initialized and thus may point to global memory. All
3852 builtin functions with the malloc attribute behave in a sane way. */
3854 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3855 make_constraint_from (vi, nonlocal_id);
3858 tmpc.type = ADDRESSOF;
3859 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3862 process_all_all_constraints (lhsc, rhsc);
3864 VEC_free (ce_s, heap, lhsc);
3867 /* For non-IPA mode, generate constraints necessary for a call of a
3868 const function that returns a pointer in the statement STMT. */
3871 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3873 struct constraint_expr rhsc;
3876 /* Treat nested const functions the same as pure functions as far
3877 as the static chain is concerned. */
3878 if (gimple_call_chain (stmt))
3880 varinfo_t uses = get_call_use_vi (stmt);
3881 make_transitive_closure_constraints (uses);
3882 make_constraint_to (uses->id, gimple_call_chain (stmt));
3883 rhsc.var = uses->id;
3886 VEC_safe_push (ce_s, heap, *results, &rhsc);
3889 /* May return arguments. */
3890 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3892 tree arg = gimple_call_arg (stmt, k);
3894 if (could_have_pointers (arg))
3896 VEC(ce_s, heap) *argc = NULL;
3898 struct constraint_expr *argp;
3899 get_constraint_for (arg, &argc);
3900 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3901 VEC_safe_push (ce_s, heap, *results, argp);
3902 VEC_free(ce_s, heap, argc);
3906 /* May return addresses of globals. */
3907 rhsc.var = nonlocal_id;
3909 rhsc.type = ADDRESSOF;
3910 VEC_safe_push (ce_s, heap, *results, &rhsc);
3913 /* For non-IPA mode, generate constraints necessary for a call to a
3914 pure function in statement STMT. */
3917 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3919 struct constraint_expr rhsc;
3921 varinfo_t uses = NULL;
3923 /* Memory reached from pointer arguments is call-used. */
3924 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3926 tree arg = gimple_call_arg (stmt, i);
3928 if (could_have_pointers (arg))
3932 uses = get_call_use_vi (stmt);
3933 make_transitive_closure_constraints (uses);
3935 make_constraint_to (uses->id, arg);
3939 /* The static chain is used as well. */
3940 if (gimple_call_chain (stmt))
3944 uses = get_call_use_vi (stmt);
3945 make_transitive_closure_constraints (uses);
3947 make_constraint_to (uses->id, gimple_call_chain (stmt));
3950 /* Pure functions may return call-used and nonlocal memory. */
3953 rhsc.var = uses->id;
3956 VEC_safe_push (ce_s, heap, *results, &rhsc);
3958 rhsc.var = nonlocal_id;
3961 VEC_safe_push (ce_s, heap, *results, &rhsc);
3965 /* Return the varinfo for the callee of CALL. */
3968 get_fi_for_callee (gimple call)
3972 /* If we can directly resolve the function being called, do so.
3973 Otherwise, it must be some sort of indirect expression that
3974 we should still be able to handle. */
3975 decl = gimple_call_fndecl (call);
3977 return get_vi_for_tree (decl);
3979 decl = gimple_call_fn (call);
3980 /* The function can be either an SSA name pointer or,
3981 worse, an OBJ_TYPE_REF. In this case we have no
3982 clue and should be getting ANYFN (well, ANYTHING for now). */
3983 if (TREE_CODE (decl) == SSA_NAME)
3985 if (TREE_CODE (decl) == SSA_NAME
3986 && (TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3987 || TREE_CODE (SSA_NAME_VAR (decl)) == RESULT_DECL)
3988 && SSA_NAME_IS_DEFAULT_DEF (decl))
3989 decl = SSA_NAME_VAR (decl);
3990 return get_vi_for_tree (decl);
3992 else if (TREE_CODE (decl) == INTEGER_CST
3993 || TREE_CODE (decl) == OBJ_TYPE_REF)
3994 return get_varinfo (anything_id);
3999 /* Walk statement T setting up aliasing constraints according to the
4000 references found in T. This function is the main part of the
4001 constraint builder. AI points to auxiliary alias information used
4002 when building alias sets and computing alias grouping heuristics. */
4005 find_func_aliases (gimple origt)
4008 VEC(ce_s, heap) *lhsc = NULL;
4009 VEC(ce_s, heap) *rhsc = NULL;
4010 struct constraint_expr *c;
4013 /* Now build constraints expressions. */
4014 if (gimple_code (t) == GIMPLE_PHI)
4016 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4018 /* Only care about pointers and structures containing
4020 if (could_have_pointers (gimple_phi_result (t)))
4025 /* For a phi node, assign all the arguments to
4027 get_constraint_for (gimple_phi_result (t), &lhsc);
4028 for (i = 0; i < gimple_phi_num_args (t); i++)
4030 tree strippedrhs = PHI_ARG_DEF (t, i);
4032 STRIP_NOPS (strippedrhs);
4033 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
4035 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
4037 struct constraint_expr *c2;
4038 while (VEC_length (ce_s, rhsc) > 0)
4040 c2 = VEC_last (ce_s, rhsc);
4041 process_constraint (new_constraint (*c, *c2));
4042 VEC_pop (ce_s, rhsc);
4048 /* In IPA mode, we need to generate constraints to pass call
4049 arguments through their calls. There are two cases,
4050 either a GIMPLE_CALL returning a value, or just a plain
4051 GIMPLE_CALL when we are not.
4053 In non-ipa mode, we need to generate constraints for each
4054 pointer passed by address. */
4055 else if (is_gimple_call (t))
4057 tree fndecl = gimple_call_fndecl (t);
4058 if (fndecl != NULL_TREE
4059 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4060 /* ??? All builtins that are handled here need to be handled
4061 in the alias-oracle query functions explicitly! */
4062 switch (DECL_FUNCTION_CODE (fndecl))
4064 /* All the following functions return a pointer to the same object
4065 as their first argument points to. The functions do not add
4066 to the ESCAPED solution. The functions make the first argument
4067 pointed to memory point to what the second argument pointed to
4068 memory points to. */
4069 case BUILT_IN_STRCPY:
4070 case BUILT_IN_STRNCPY:
4071 case BUILT_IN_BCOPY:
4072 case BUILT_IN_MEMCPY:
4073 case BUILT_IN_MEMMOVE:
4074 case BUILT_IN_MEMPCPY:
4075 case BUILT_IN_STPCPY:
4076 case BUILT_IN_STPNCPY:
4077 case BUILT_IN_STRCAT:
4078 case BUILT_IN_STRNCAT:
4080 tree res = gimple_call_lhs (t);
4081 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4082 == BUILT_IN_BCOPY ? 1 : 0));
4083 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4084 == BUILT_IN_BCOPY ? 0 : 1));
4085 if (res != NULL_TREE)
4087 get_constraint_for (res, &lhsc);
4088 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4089 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4090 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4091 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4093 get_constraint_for (dest, &rhsc);
4094 process_all_all_constraints (lhsc, rhsc);
4095 VEC_free (ce_s, heap, lhsc);
4096 VEC_free (ce_s, heap, rhsc);
4098 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4099 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4102 process_all_all_constraints (lhsc, rhsc);
4103 VEC_free (ce_s, heap, lhsc);
4104 VEC_free (ce_s, heap, rhsc);
4107 case BUILT_IN_MEMSET:
4109 tree res = gimple_call_lhs (t);
4110 tree dest = gimple_call_arg (t, 0);
4113 struct constraint_expr ac;
4114 if (res != NULL_TREE)
4116 get_constraint_for (res, &lhsc);
4117 get_constraint_for (dest, &rhsc);
4118 process_all_all_constraints (lhsc, rhsc);
4119 VEC_free (ce_s, heap, lhsc);
4120 VEC_free (ce_s, heap, rhsc);
4122 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4124 if (flag_delete_null_pointer_checks
4125 && integer_zerop (gimple_call_arg (t, 1)))
4127 ac.type = ADDRESSOF;
4128 ac.var = nothing_id;
4133 ac.var = integer_id;
4136 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4137 process_constraint (new_constraint (*lhsp, ac));
4138 VEC_free (ce_s, heap, lhsc);
4141 /* All the following functions do not return pointers, do not
4142 modify the points-to sets of memory reachable from their
4143 arguments and do not add to the ESCAPED solution. */
4144 case BUILT_IN_SINCOS:
4145 case BUILT_IN_SINCOSF:
4146 case BUILT_IN_SINCOSL:
4147 case BUILT_IN_FREXP:
4148 case BUILT_IN_FREXPF:
4149 case BUILT_IN_FREXPL:
4150 case BUILT_IN_GAMMA_R:
4151 case BUILT_IN_GAMMAF_R:
4152 case BUILT_IN_GAMMAL_R:
4153 case BUILT_IN_LGAMMA_R:
4154 case BUILT_IN_LGAMMAF_R:
4155 case BUILT_IN_LGAMMAL_R:
4157 case BUILT_IN_MODFF:
4158 case BUILT_IN_MODFL:
4159 case BUILT_IN_REMQUO:
4160 case BUILT_IN_REMQUOF:
4161 case BUILT_IN_REMQUOL:
4164 /* Trampolines are special - they set up passing the static
4166 case BUILT_IN_INIT_TRAMPOLINE:
4168 tree tramp = gimple_call_arg (t, 0);
4169 tree nfunc = gimple_call_arg (t, 1);
4170 tree frame = gimple_call_arg (t, 2);
4172 struct constraint_expr lhs, *rhsp;
4175 varinfo_t nfi = NULL;
4176 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4177 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4180 lhs = get_function_part_constraint (nfi, fi_static_chain);
4181 get_constraint_for (frame, &rhsc);
4182 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
4183 process_constraint (new_constraint (lhs, *rhsp));
4184 VEC_free (ce_s, heap, rhsc);
4186 /* Make the frame point to the function for
4187 the trampoline adjustment call. */
4188 get_constraint_for (tramp, &lhsc);
4190 get_constraint_for (nfunc, &rhsc);
4191 process_all_all_constraints (lhsc, rhsc);
4192 VEC_free (ce_s, heap, rhsc);
4193 VEC_free (ce_s, heap, lhsc);
4198 /* Else fallthru to generic handling which will let
4199 the frame escape. */
4202 case BUILT_IN_ADJUST_TRAMPOLINE:
4204 tree tramp = gimple_call_arg (t, 0);
4205 tree res = gimple_call_lhs (t);
4206 if (in_ipa_mode && res)
4208 get_constraint_for (res, &lhsc);
4209 get_constraint_for (tramp, &rhsc);
4211 process_all_all_constraints (lhsc, rhsc);
4212 VEC_free (ce_s, heap, rhsc);
4213 VEC_free (ce_s, heap, lhsc);
4217 /* Variadic argument handling needs to be handled in IPA
4219 case BUILT_IN_VA_START:
4223 tree valist = gimple_call_arg (t, 0);
4224 struct constraint_expr rhs, *lhsp;
4226 /* The va_list gets access to pointers in variadic
4228 fi = lookup_vi_for_tree (cfun->decl);
4229 gcc_assert (fi != NULL);
4230 get_constraint_for (valist, &lhsc);
4232 rhs = get_function_part_constraint (fi, ~0);
4233 rhs.type = ADDRESSOF;
4234 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4235 process_constraint (new_constraint (*lhsp, rhs));
4236 VEC_free (ce_s, heap, lhsc);
4237 /* va_list is clobbered. */
4238 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4243 /* va_end doesn't have any effect that matters. */
4244 case BUILT_IN_VA_END:
4246 /* Alternate return. Simply give up for now. */
4247 case BUILT_IN_RETURN:
4251 || !(fi = get_vi_for_tree (cfun->decl)))
4252 make_constraint_from (get_varinfo (escaped_id), anything_id);
4253 else if (in_ipa_mode
4256 struct constraint_expr lhs, rhs;
4257 lhs = get_function_part_constraint (fi, fi_result);
4258 rhs.var = anything_id;
4261 process_constraint (new_constraint (lhs, rhs));
4265 /* printf-style functions may have hooks to set pointers to
4266 point to somewhere into the generated string. Leave them
4267 for a later excercise... */
4269 /* Fallthru to general call handling. */;
4273 && (!(fi = lookup_vi_for_tree (fndecl))
4274 || !fi->is_fn_info)))
4276 VEC(ce_s, heap) *rhsc = NULL;
4277 int flags = gimple_call_flags (t);
4279 /* Const functions can return their arguments and addresses
4280 of global memory but not of escaped memory. */
4281 if (flags & (ECF_CONST|ECF_NOVOPS))
4283 if (gimple_call_lhs (t)
4284 && could_have_pointers (gimple_call_lhs (t)))
4285 handle_const_call (t, &rhsc);
4287 /* Pure functions can return addresses in and of memory
4288 reachable from their arguments, but they are not an escape
4289 point for reachable memory of their arguments. */
4290 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4291 handle_pure_call (t, &rhsc);
4293 handle_rhs_call (t, &rhsc);
4294 if (gimple_call_lhs (t)
4295 && could_have_pointers (gimple_call_lhs (t)))
4296 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4297 VEC_free (ce_s, heap, rhsc);
4304 fi = get_fi_for_callee (t);
4306 /* Assign all the passed arguments to the appropriate incoming
4307 parameters of the function. */
4308 for (j = 0; j < gimple_call_num_args (t); j++)
4310 struct constraint_expr lhs ;
4311 struct constraint_expr *rhsp;
4312 tree arg = gimple_call_arg (t, j);
4314 if (!could_have_pointers (arg))
4317 get_constraint_for (arg, &rhsc);
4318 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4319 while (VEC_length (ce_s, rhsc) != 0)
4321 rhsp = VEC_last (ce_s, rhsc);
4322 process_constraint (new_constraint (lhs, *rhsp));
4323 VEC_pop (ce_s, rhsc);
4327 /* If we are returning a value, assign it to the result. */
4328 lhsop = gimple_call_lhs (t);
4330 && type_could_have_pointers (TREE_TYPE (lhsop)))
4332 struct constraint_expr rhs;
4333 struct constraint_expr *lhsp;
4335 get_constraint_for (lhsop, &lhsc);
4336 rhs = get_function_part_constraint (fi, fi_result);
4338 && DECL_RESULT (fndecl)
4339 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4341 VEC(ce_s, heap) *tem = NULL;
4342 VEC_safe_push (ce_s, heap, tem, &rhs);
4344 rhs = *VEC_index (ce_s, tem, 0);
4345 VEC_free(ce_s, heap, tem);
4347 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4348 process_constraint (new_constraint (*lhsp, rhs));
4351 /* If we pass the result decl by reference, honor that. */
4354 && DECL_RESULT (fndecl)
4355 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4357 struct constraint_expr lhs;
4358 struct constraint_expr *rhsp;
4360 get_constraint_for_address_of (lhsop, &rhsc);
4361 lhs = get_function_part_constraint (fi, fi_result);
4362 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4363 process_constraint (new_constraint (lhs, *rhsp));
4364 VEC_free (ce_s, heap, rhsc);
4367 /* If we use a static chain, pass it along. */
4368 if (gimple_call_chain (t))
4370 struct constraint_expr lhs;
4371 struct constraint_expr *rhsp;
4373 get_constraint_for (gimple_call_chain (t), &rhsc);
4374 lhs = get_function_part_constraint (fi, fi_static_chain);
4375 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4376 process_constraint (new_constraint (lhs, *rhsp));
4380 /* Otherwise, just a regular assignment statement. Only care about
4381 operations with pointer result, others are dealt with as escape
4382 points if they have pointer operands. */
4383 else if (is_gimple_assign (t)
4384 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4386 /* Otherwise, just a regular assignment statement. */
4387 tree lhsop = gimple_assign_lhs (t);
4388 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4390 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4391 do_structure_copy (lhsop, rhsop);
4394 struct constraint_expr temp;
4395 get_constraint_for (lhsop, &lhsc);
4397 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4398 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4399 gimple_assign_rhs2 (t), &rhsc);
4400 else if (gimple_assign_rhs_code (t) == BIT_AND_EXPR
4401 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4403 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4404 the pointer. Handle it by offsetting it by UNKNOWN. */
4405 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4408 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4409 && !(POINTER_TYPE_P (gimple_expr_type (t))
4410 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4411 || gimple_assign_single_p (t))
4412 get_constraint_for (rhsop, &rhsc);
4415 temp.type = ADDRESSOF;
4416 temp.var = anything_id;
4418 VEC_safe_push (ce_s, heap, rhsc, &temp);
4420 process_all_all_constraints (lhsc, rhsc);
4422 /* If there is a store to a global variable the rhs escapes. */
4423 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4425 && is_global_var (lhsop)
4427 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4428 make_escape_constraint (rhsop);
4429 /* If this is a conversion of a non-restrict pointer to a
4430 restrict pointer track it with a new heapvar. */
4431 else if (gimple_assign_cast_p (t)
4432 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4433 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4434 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4435 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4436 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4439 /* For conversions of pointers to non-pointers the pointer escapes. */
4440 else if (gimple_assign_cast_p (t)
4441 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4442 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4444 make_escape_constraint (gimple_assign_rhs1 (t));
4446 /* Handle escapes through return. */
4447 else if (gimple_code (t) == GIMPLE_RETURN
4448 && gimple_return_retval (t) != NULL_TREE
4449 && could_have_pointers (gimple_return_retval (t)))
4453 || !(fi = get_vi_for_tree (cfun->decl)))
4454 make_escape_constraint (gimple_return_retval (t));
4455 else if (in_ipa_mode
4458 struct constraint_expr lhs ;
4459 struct constraint_expr *rhsp;
4462 lhs = get_function_part_constraint (fi, fi_result);
4463 get_constraint_for (gimple_return_retval (t), &rhsc);
4464 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4465 process_constraint (new_constraint (lhs, *rhsp));
4468 /* Handle asms conservatively by adding escape constraints to everything. */
4469 else if (gimple_code (t) == GIMPLE_ASM)
4471 unsigned i, noutputs;
4472 const char **oconstraints;
4473 const char *constraint;
4474 bool allows_mem, allows_reg, is_inout;
4476 noutputs = gimple_asm_noutputs (t);
4477 oconstraints = XALLOCAVEC (const char *, noutputs);
4479 for (i = 0; i < noutputs; ++i)
4481 tree link = gimple_asm_output_op (t, i);
4482 tree op = TREE_VALUE (link);
4484 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4485 oconstraints[i] = constraint;
4486 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4487 &allows_reg, &is_inout);
4489 /* A memory constraint makes the address of the operand escape. */
4490 if (!allows_reg && allows_mem)
4491 make_escape_constraint (build_fold_addr_expr (op));
4493 /* The asm may read global memory, so outputs may point to
4494 any global memory. */
4495 if (op && could_have_pointers (op))
4497 VEC(ce_s, heap) *lhsc = NULL;
4498 struct constraint_expr rhsc, *lhsp;
4500 get_constraint_for (op, &lhsc);
4501 rhsc.var = nonlocal_id;
4504 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4505 process_constraint (new_constraint (*lhsp, rhsc));
4506 VEC_free (ce_s, heap, lhsc);
4509 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4511 tree link = gimple_asm_input_op (t, i);
4512 tree op = TREE_VALUE (link);
4514 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4516 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4517 &allows_mem, &allows_reg);
4519 /* A memory constraint makes the address of the operand escape. */
4520 if (!allows_reg && allows_mem)
4521 make_escape_constraint (build_fold_addr_expr (op));
4522 /* Strictly we'd only need the constraint to ESCAPED if
4523 the asm clobbers memory, otherwise using something
4524 along the lines of per-call clobbers/uses would be enough. */
4525 else if (op && could_have_pointers (op))
4526 make_escape_constraint (op);
4530 VEC_free (ce_s, heap, rhsc);
4531 VEC_free (ce_s, heap, lhsc);
4535 /* Create a constraint adding to the clobber set of FI the memory
4536 pointed to by PTR. */
4539 process_ipa_clobber (varinfo_t fi, tree ptr)
4541 VEC(ce_s, heap) *ptrc = NULL;
4542 struct constraint_expr *c, lhs;
4544 get_constraint_for (ptr, &ptrc);
4545 lhs = get_function_part_constraint (fi, fi_clobbers);
4546 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4547 process_constraint (new_constraint (lhs, *c));
4548 VEC_free (ce_s, heap, ptrc);
4551 /* Walk statement T setting up clobber and use constraints according to the
4552 references found in T. This function is a main part of the
4553 IPA constraint builder. */
4556 find_func_clobbers (gimple origt)
4559 VEC(ce_s, heap) *lhsc = NULL;
4560 VEC(ce_s, heap) *rhsc = NULL;
4563 /* Add constraints for clobbered/used in IPA mode.
4564 We are not interested in what automatic variables are clobbered
4565 or used as we only use the information in the caller to which
4566 they do not escape. */
4567 gcc_assert (in_ipa_mode);
4569 /* If the stmt refers to memory in any way it better had a VUSE. */
4570 if (gimple_vuse (t) == NULL_TREE)
4573 /* We'd better have function information for the current function. */
4574 fi = lookup_vi_for_tree (cfun->decl);
4575 gcc_assert (fi != NULL);
4577 /* Account for stores in assignments and calls. */
4578 if (gimple_vdef (t) != NULL_TREE
4579 && gimple_has_lhs (t))
4581 tree lhs = gimple_get_lhs (t);
4583 while (handled_component_p (tem))
4584 tem = TREE_OPERAND (tem, 0);
4586 && !auto_var_in_fn_p (tem, cfun->decl))
4587 || INDIRECT_REF_P (tem)
4588 || (TREE_CODE (tem) == MEM_REF
4589 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4591 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4593 struct constraint_expr lhsc, *rhsp;
4595 lhsc = get_function_part_constraint (fi, fi_clobbers);
4596 get_constraint_for_address_of (lhs, &rhsc);
4597 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4598 process_constraint (new_constraint (lhsc, *rhsp));
4599 VEC_free (ce_s, heap, rhsc);
4603 /* Account for uses in assigments and returns. */
4604 if (gimple_assign_single_p (t)
4605 || (gimple_code (t) == GIMPLE_RETURN
4606 && gimple_return_retval (t) != NULL_TREE))
4608 tree rhs = (gimple_assign_single_p (t)
4609 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4611 while (handled_component_p (tem))
4612 tem = TREE_OPERAND (tem, 0);
4614 && !auto_var_in_fn_p (tem, cfun->decl))
4615 || INDIRECT_REF_P (tem)
4616 || (TREE_CODE (tem) == MEM_REF
4617 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4619 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4621 struct constraint_expr lhs, *rhsp;
4623 lhs = get_function_part_constraint (fi, fi_uses);
4624 get_constraint_for_address_of (rhs, &rhsc);
4625 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4626 process_constraint (new_constraint (lhs, *rhsp));
4627 VEC_free (ce_s, heap, rhsc);
4631 if (is_gimple_call (t))
4633 varinfo_t cfi = NULL;
4634 tree decl = gimple_call_fndecl (t);
4635 struct constraint_expr lhs, rhs;
4638 /* For builtins we do not have separate function info. For those
4639 we do not generate escapes for we have to generate clobbers/uses. */
4641 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4642 switch (DECL_FUNCTION_CODE (decl))
4644 /* The following functions use and clobber memory pointed to
4645 by their arguments. */
4646 case BUILT_IN_STRCPY:
4647 case BUILT_IN_STRNCPY:
4648 case BUILT_IN_BCOPY:
4649 case BUILT_IN_MEMCPY:
4650 case BUILT_IN_MEMMOVE:
4651 case BUILT_IN_MEMPCPY:
4652 case BUILT_IN_STPCPY:
4653 case BUILT_IN_STPNCPY:
4654 case BUILT_IN_STRCAT:
4655 case BUILT_IN_STRNCAT:
4657 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4658 == BUILT_IN_BCOPY ? 1 : 0));
4659 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4660 == BUILT_IN_BCOPY ? 0 : 1));
4662 struct constraint_expr *rhsp, *lhsp;
4663 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4664 lhs = get_function_part_constraint (fi, fi_clobbers);
4665 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4666 process_constraint (new_constraint (lhs, *lhsp));
4667 VEC_free (ce_s, heap, lhsc);
4668 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4669 lhs = get_function_part_constraint (fi, fi_uses);
4670 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4671 process_constraint (new_constraint (lhs, *rhsp));
4672 VEC_free (ce_s, heap, rhsc);
4675 /* The following function clobbers memory pointed to by
4677 case BUILT_IN_MEMSET:
4679 tree dest = gimple_call_arg (t, 0);
4682 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4683 lhs = get_function_part_constraint (fi, fi_clobbers);
4684 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4685 process_constraint (new_constraint (lhs, *lhsp));
4686 VEC_free (ce_s, heap, lhsc);
4689 /* The following functions clobber their second and third
4691 case BUILT_IN_SINCOS:
4692 case BUILT_IN_SINCOSF:
4693 case BUILT_IN_SINCOSL:
4695 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4696 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4699 /* The following functions clobber their second argument. */
4700 case BUILT_IN_FREXP:
4701 case BUILT_IN_FREXPF:
4702 case BUILT_IN_FREXPL:
4703 case BUILT_IN_LGAMMA_R:
4704 case BUILT_IN_LGAMMAF_R:
4705 case BUILT_IN_LGAMMAL_R:
4706 case BUILT_IN_GAMMA_R:
4707 case BUILT_IN_GAMMAF_R:
4708 case BUILT_IN_GAMMAL_R:
4710 case BUILT_IN_MODFF:
4711 case BUILT_IN_MODFL:
4713 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4716 /* The following functions clobber their third argument. */
4717 case BUILT_IN_REMQUO:
4718 case BUILT_IN_REMQUOF:
4719 case BUILT_IN_REMQUOL:
4721 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4724 /* The following functions neither read nor clobber memory. */
4727 /* Trampolines are of no interest to us. */
4728 case BUILT_IN_INIT_TRAMPOLINE:
4729 case BUILT_IN_ADJUST_TRAMPOLINE:
4731 case BUILT_IN_VA_START:
4732 case BUILT_IN_VA_END:
4734 /* printf-style functions may have hooks to set pointers to
4735 point to somewhere into the generated string. Leave them
4736 for a later excercise... */
4738 /* Fallthru to general call handling. */;
4741 /* Parameters passed by value are used. */
4742 lhs = get_function_part_constraint (fi, fi_uses);
4743 for (i = 0; i < gimple_call_num_args (t); i++)
4745 struct constraint_expr *rhsp;
4746 tree arg = gimple_call_arg (t, i);
4748 if (TREE_CODE (arg) == SSA_NAME
4749 || is_gimple_min_invariant (arg))
4752 get_constraint_for_address_of (arg, &rhsc);
4753 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4754 process_constraint (new_constraint (lhs, *rhsp));
4755 VEC_free (ce_s, heap, rhsc);
4758 /* Build constraints for propagating clobbers/uses along the
4760 cfi = get_fi_for_callee (t);
4761 if (cfi->id == anything_id)
4763 if (gimple_vdef (t))
4764 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4766 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4771 /* For callees without function info (that's external functions),
4772 ESCAPED is clobbered and used. */
4773 if (gimple_call_fndecl (t)
4774 && !cfi->is_fn_info)
4778 if (gimple_vdef (t))
4779 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4781 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4783 /* Also honor the call statement use/clobber info. */
4784 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4785 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4787 if ((vi = lookup_call_use_vi (t)) != NULL)
4788 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4793 /* Otherwise the caller clobbers and uses what the callee does.
4794 ??? This should use a new complex constraint that filters
4795 local variables of the callee. */
4796 if (gimple_vdef (t))
4798 lhs = get_function_part_constraint (fi, fi_clobbers);
4799 rhs = get_function_part_constraint (cfi, fi_clobbers);
4800 process_constraint (new_constraint (lhs, rhs));
4802 lhs = get_function_part_constraint (fi, fi_uses);
4803 rhs = get_function_part_constraint (cfi, fi_uses);
4804 process_constraint (new_constraint (lhs, rhs));
4806 else if (gimple_code (t) == GIMPLE_ASM)
4808 /* ??? Ick. We can do better. */
4809 if (gimple_vdef (t))
4810 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4812 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4816 VEC_free (ce_s, heap, rhsc);
4820 /* Find the first varinfo in the same variable as START that overlaps with
4821 OFFSET. Return NULL if we can't find one. */
4824 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4826 /* If the offset is outside of the variable, bail out. */
4827 if (offset >= start->fullsize)
4830 /* If we cannot reach offset from start, lookup the first field
4831 and start from there. */
4832 if (start->offset > offset)
4833 start = lookup_vi_for_tree (start->decl);
4837 /* We may not find a variable in the field list with the actual
4838 offset when when we have glommed a structure to a variable.
4839 In that case, however, offset should still be within the size
4841 if (offset >= start->offset
4842 && (offset - start->offset) < start->size)
4851 /* Find the first varinfo in the same variable as START that overlaps with
4852 OFFSET. If there is no such varinfo the varinfo directly preceding
4853 OFFSET is returned. */
4856 first_or_preceding_vi_for_offset (varinfo_t start,
4857 unsigned HOST_WIDE_INT offset)
4859 /* If we cannot reach offset from start, lookup the first field
4860 and start from there. */
4861 if (start->offset > offset)
4862 start = lookup_vi_for_tree (start->decl);
4864 /* We may not find a variable in the field list with the actual
4865 offset when when we have glommed a structure to a variable.
4866 In that case, however, offset should still be within the size
4868 If we got beyond the offset we look for return the field
4869 directly preceding offset which may be the last field. */
4871 && offset >= start->offset
4872 && !((offset - start->offset) < start->size))
4873 start = start->next;
4879 /* This structure is used during pushing fields onto the fieldstack
4880 to track the offset of the field, since bitpos_of_field gives it
4881 relative to its immediate containing type, and we want it relative
4882 to the ultimate containing object. */
4886 /* Offset from the base of the base containing object to this field. */
4887 HOST_WIDE_INT offset;
4889 /* Size, in bits, of the field. */
4890 unsigned HOST_WIDE_INT size;
4892 unsigned has_unknown_size : 1;
4894 unsigned may_have_pointers : 1;
4896 unsigned only_restrict_pointers : 1;
4898 typedef struct fieldoff fieldoff_s;
4900 DEF_VEC_O(fieldoff_s);
4901 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4903 /* qsort comparison function for two fieldoff's PA and PB */
4906 fieldoff_compare (const void *pa, const void *pb)
4908 const fieldoff_s *foa = (const fieldoff_s *)pa;
4909 const fieldoff_s *fob = (const fieldoff_s *)pb;
4910 unsigned HOST_WIDE_INT foasize, fobsize;
4912 if (foa->offset < fob->offset)
4914 else if (foa->offset > fob->offset)
4917 foasize = foa->size;
4918 fobsize = fob->size;
4919 if (foasize < fobsize)
4921 else if (foasize > fobsize)
4926 /* Sort a fieldstack according to the field offset and sizes. */
4928 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4930 qsort (VEC_address (fieldoff_s, fieldstack),
4931 VEC_length (fieldoff_s, fieldstack),
4932 sizeof (fieldoff_s),
4936 /* Return true if V is a tree that we can have subvars for.
4937 Normally, this is any aggregate type. Also complex
4938 types which are not gimple registers can have subvars. */
4941 var_can_have_subvars (const_tree v)
4943 /* Volatile variables should never have subvars. */
4944 if (TREE_THIS_VOLATILE (v))
4947 /* Non decls or memory tags can never have subvars. */
4951 /* Aggregates without overlapping fields can have subvars. */
4952 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4958 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4959 the fields of TYPE onto fieldstack, recording their offsets along
4962 OFFSET is used to keep track of the offset in this entire
4963 structure, rather than just the immediately containing structure.
4964 Returns false if the caller is supposed to handle the field we
4968 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4969 HOST_WIDE_INT offset, bool must_have_pointers_p)
4972 bool empty_p = true;
4974 if (TREE_CODE (type) != RECORD_TYPE)
4977 /* If the vector of fields is growing too big, bail out early.
4978 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4980 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4983 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4984 if (TREE_CODE (field) == FIELD_DECL)
4987 HOST_WIDE_INT foff = bitpos_of_field (field);
4989 if (!var_can_have_subvars (field)
4990 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4991 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4993 else if (!push_fields_onto_fieldstack
4994 (TREE_TYPE (field), fieldstack, offset + foff,
4995 must_have_pointers_p)
4996 && (DECL_SIZE (field)
4997 && !integer_zerop (DECL_SIZE (field))))
4998 /* Empty structures may have actual size, like in C++. So
4999 see if we didn't push any subfields and the size is
5000 nonzero, push the field onto the stack. */
5005 fieldoff_s *pair = NULL;
5006 bool has_unknown_size = false;
5008 if (!VEC_empty (fieldoff_s, *fieldstack))
5009 pair = VEC_last (fieldoff_s, *fieldstack);
5011 if (!DECL_SIZE (field)
5012 || !host_integerp (DECL_SIZE (field), 1))
5013 has_unknown_size = true;
5015 /* If adjacent fields do not contain pointers merge them. */
5017 && !pair->may_have_pointers
5018 && !pair->has_unknown_size
5019 && !has_unknown_size
5020 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
5021 && !must_have_pointers_p
5022 && !could_have_pointers (field))
5024 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5028 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5029 pair->offset = offset + foff;
5030 pair->has_unknown_size = has_unknown_size;
5031 if (!has_unknown_size)
5032 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5035 pair->may_have_pointers
5036 = must_have_pointers_p || could_have_pointers (field);
5037 pair->only_restrict_pointers
5038 = (!has_unknown_size
5039 && POINTER_TYPE_P (TREE_TYPE (field))
5040 && TYPE_RESTRICT (TREE_TYPE (field)));
5050 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5051 if it is a varargs function. */
5054 count_num_arguments (tree decl, bool *is_varargs)
5056 unsigned int num = 0;
5059 /* Capture named arguments for K&R functions. They do not
5060 have a prototype and thus no TYPE_ARG_TYPES. */
5061 for (t = DECL_ARGUMENTS (decl); t; t = TREE_CHAIN (t))
5064 /* Check if the function has variadic arguments. */
5065 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5066 if (TREE_VALUE (t) == void_type_node)
5074 /* Creation function node for DECL, using NAME, and return the index
5075 of the variable we've created for the function. */
5078 create_function_info_for (tree decl, const char *name)
5080 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5081 varinfo_t vi, prev_vi;
5084 bool is_varargs = false;
5085 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5087 /* Create the variable info. */
5089 vi = new_var_info (decl, name);
5092 vi->fullsize = fi_parm_base + num_args;
5094 vi->may_have_pointers = false;
5097 insert_vi_for_tree (vi->decl, vi);
5101 /* Create a variable for things the function clobbers and one for
5102 things the function uses. */
5104 varinfo_t clobbervi, usevi;
5105 const char *newname;
5108 asprintf (&tempname, "%s.clobber", name);
5109 newname = ggc_strdup (tempname);
5112 clobbervi = new_var_info (NULL, newname);
5113 clobbervi->offset = fi_clobbers;
5114 clobbervi->size = 1;
5115 clobbervi->fullsize = vi->fullsize;
5116 clobbervi->is_full_var = true;
5117 clobbervi->is_global_var = false;
5118 gcc_assert (prev_vi->offset < clobbervi->offset);
5119 prev_vi->next = clobbervi;
5120 prev_vi = clobbervi;
5122 asprintf (&tempname, "%s.use", name);
5123 newname = ggc_strdup (tempname);
5126 usevi = new_var_info (NULL, newname);
5127 usevi->offset = fi_uses;
5129 usevi->fullsize = vi->fullsize;
5130 usevi->is_full_var = true;
5131 usevi->is_global_var = false;
5132 gcc_assert (prev_vi->offset < usevi->offset);
5133 prev_vi->next = usevi;
5137 /* And one for the static chain. */
5138 if (fn->static_chain_decl != NULL_TREE)
5141 const char *newname;
5144 asprintf (&tempname, "%s.chain", name);
5145 newname = ggc_strdup (tempname);
5148 chainvi = new_var_info (fn->static_chain_decl, newname);
5149 chainvi->offset = fi_static_chain;
5151 chainvi->fullsize = vi->fullsize;
5152 chainvi->is_full_var = true;
5153 chainvi->is_global_var = false;
5154 gcc_assert (prev_vi->offset < chainvi->offset);
5155 prev_vi->next = chainvi;
5157 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5160 /* Create a variable for the return var. */
5161 if (DECL_RESULT (decl) != NULL
5162 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5165 const char *newname;
5167 tree resultdecl = decl;
5169 if (DECL_RESULT (decl))
5170 resultdecl = DECL_RESULT (decl);
5172 asprintf (&tempname, "%s.result", name);
5173 newname = ggc_strdup (tempname);
5176 resultvi = new_var_info (resultdecl, newname);
5177 resultvi->offset = fi_result;
5179 resultvi->fullsize = vi->fullsize;
5180 resultvi->is_full_var = true;
5181 if (DECL_RESULT (decl))
5182 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5183 gcc_assert (prev_vi->offset < resultvi->offset);
5184 prev_vi->next = resultvi;
5186 if (DECL_RESULT (decl))
5187 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5190 /* Set up variables for each argument. */
5191 arg = DECL_ARGUMENTS (decl);
5192 for (i = 0; i < num_args; i++)
5195 const char *newname;
5197 tree argdecl = decl;
5202 asprintf (&tempname, "%s.arg%d", name, i);
5203 newname = ggc_strdup (tempname);
5206 argvi = new_var_info (argdecl, newname);
5207 argvi->offset = fi_parm_base + i;
5209 argvi->is_full_var = true;
5210 argvi->fullsize = vi->fullsize;
5212 argvi->may_have_pointers = could_have_pointers (arg);
5213 gcc_assert (prev_vi->offset < argvi->offset);
5214 prev_vi->next = argvi;
5218 insert_vi_for_tree (arg, argvi);
5219 arg = TREE_CHAIN (arg);
5223 /* Add one representative for all further args. */
5227 const char *newname;
5231 asprintf (&tempname, "%s.varargs", name);
5232 newname = ggc_strdup (tempname);
5235 /* We need sth that can be pointed to for va_start. */
5236 decl = create_tmp_var_raw (ptr_type_node, name);
5239 argvi = new_var_info (decl, newname);
5240 argvi->offset = fi_parm_base + num_args;
5242 argvi->is_full_var = true;
5243 argvi->is_heap_var = true;
5244 argvi->fullsize = vi->fullsize;
5245 gcc_assert (prev_vi->offset < argvi->offset);
5246 prev_vi->next = argvi;
5254 /* Return true if FIELDSTACK contains fields that overlap.
5255 FIELDSTACK is assumed to be sorted by offset. */
5258 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5260 fieldoff_s *fo = NULL;
5262 HOST_WIDE_INT lastoffset = -1;
5264 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5266 if (fo->offset == lastoffset)
5268 lastoffset = fo->offset;
5273 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5274 This will also create any varinfo structures necessary for fields
5278 create_variable_info_for_1 (tree decl, const char *name)
5280 varinfo_t vi, newvi;
5281 tree decl_type = TREE_TYPE (decl);
5282 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5283 VEC (fieldoff_s,heap) *fieldstack = NULL;
5288 || !host_integerp (declsize, 1))
5290 vi = new_var_info (decl, name);
5294 vi->is_unknown_size_var = true;
5295 vi->is_full_var = true;
5296 vi->may_have_pointers = could_have_pointers (decl);
5300 /* Collect field information. */
5301 if (use_field_sensitive
5302 && var_can_have_subvars (decl)
5303 /* ??? Force us to not use subfields for global initializers
5304 in IPA mode. Else we'd have to parse arbitrary initializers. */
5306 && is_global_var (decl)
5307 && DECL_INITIAL (decl)))
5309 fieldoff_s *fo = NULL;
5310 bool notokay = false;
5313 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5315 || DECL_EXTERNAL (decl)
5316 || TREE_ADDRESSABLE (decl));
5318 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5319 if (fo->has_unknown_size
5326 /* We can't sort them if we have a field with a variable sized type,
5327 which will make notokay = true. In that case, we are going to return
5328 without creating varinfos for the fields anyway, so sorting them is a
5332 sort_fieldstack (fieldstack);
5333 /* Due to some C++ FE issues, like PR 22488, we might end up
5334 what appear to be overlapping fields even though they,
5335 in reality, do not overlap. Until the C++ FE is fixed,
5336 we will simply disable field-sensitivity for these cases. */
5337 notokay = check_for_overlaps (fieldstack);
5341 VEC_free (fieldoff_s, heap, fieldstack);
5344 /* If we didn't end up collecting sub-variables create a full
5345 variable for the decl. */
5346 if (VEC_length (fieldoff_s, fieldstack) <= 1
5347 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5349 vi = new_var_info (decl, name);
5351 vi->may_have_pointers = could_have_pointers (decl);
5352 vi->fullsize = TREE_INT_CST_LOW (declsize);
5353 vi->size = vi->fullsize;
5354 vi->is_full_var = true;
5355 VEC_free (fieldoff_s, heap, fieldstack);
5359 vi = new_var_info (decl, name);
5360 vi->fullsize = TREE_INT_CST_LOW (declsize);
5361 for (i = 0, newvi = vi;
5362 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5363 ++i, newvi = newvi->next)
5365 const char *newname = "NULL";
5370 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5371 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5372 newname = ggc_strdup (tempname);
5375 newvi->name = newname;
5376 newvi->offset = fo->offset;
5377 newvi->size = fo->size;
5378 newvi->fullsize = vi->fullsize;
5379 newvi->may_have_pointers = fo->may_have_pointers;
5380 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5381 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5382 newvi->next = new_var_info (decl, name);
5385 VEC_free (fieldoff_s, heap, fieldstack);
5391 create_variable_info_for (tree decl, const char *name)
5393 varinfo_t vi = create_variable_info_for_1 (decl, name);
5394 unsigned int id = vi->id;
5396 insert_vi_for_tree (decl, vi);
5398 /* Create initial constraints for globals. */
5399 for (; vi; vi = vi->next)
5401 if (!vi->may_have_pointers
5402 || !vi->is_global_var)
5405 /* Mark global restrict qualified pointers. */
5406 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5407 && TYPE_RESTRICT (TREE_TYPE (decl)))
5408 || vi->only_restrict_pointers)
5409 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5411 /* For escaped variables initialize them from nonlocal. */
5413 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5414 make_copy_constraint (vi, nonlocal_id);
5416 /* If this is a global variable with an initializer and we are in
5417 IPA mode generate constraints for it. In non-IPA mode
5418 the initializer from nonlocal is all we need. */
5420 && DECL_INITIAL (decl))
5422 VEC (ce_s, heap) *rhsc = NULL;
5423 struct constraint_expr lhs, *rhsp;
5425 get_constraint_for (DECL_INITIAL (decl), &rhsc);
5429 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5430 process_constraint (new_constraint (lhs, *rhsp));
5431 /* If this is a variable that escapes from the unit
5432 the initializer escapes as well. */
5433 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5435 lhs.var = escaped_id;
5438 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5439 process_constraint (new_constraint (lhs, *rhsp));
5441 VEC_free (ce_s, heap, rhsc);
5448 /* Print out the points-to solution for VAR to FILE. */
5451 dump_solution_for_var (FILE *file, unsigned int var)
5453 varinfo_t vi = get_varinfo (var);
5457 /* Dump the solution for unified vars anyway, this avoids difficulties
5458 in scanning dumps in the testsuite. */
5459 fprintf (file, "%s = { ", vi->name);
5460 vi = get_varinfo (find (var));
5461 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5462 fprintf (file, "%s ", get_varinfo (i)->name);
5463 fprintf (file, "}");
5465 /* But note when the variable was unified. */
5467 fprintf (file, " same as %s", vi->name);
5469 fprintf (file, "\n");
5472 /* Print the points-to solution for VAR to stdout. */
5475 debug_solution_for_var (unsigned int var)
5477 dump_solution_for_var (stdout, var);
5480 /* Create varinfo structures for all of the variables in the
5481 function for intraprocedural mode. */
5484 intra_create_variable_infos (void)
5488 /* For each incoming pointer argument arg, create the constraint ARG
5489 = NONLOCAL or a dummy variable if it is a restrict qualified
5490 passed-by-reference argument. */
5491 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
5495 if (!could_have_pointers (t))
5498 /* For restrict qualified pointers to objects passed by
5499 reference build a real representative for the pointed-to object. */
5500 if (DECL_BY_REFERENCE (t)
5501 && POINTER_TYPE_P (TREE_TYPE (t))
5502 && TYPE_RESTRICT (TREE_TYPE (t)))
5504 struct constraint_expr lhsc, rhsc;
5506 tree heapvar = heapvar_lookup (t, 0);
5507 if (heapvar == NULL_TREE)
5510 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5512 DECL_EXTERNAL (heapvar) = 1;
5513 heapvar_insert (t, 0, heapvar);
5514 ann = get_var_ann (heapvar);
5515 ann->is_heapvar = 1;
5517 if (gimple_referenced_vars (cfun))
5518 add_referenced_var (heapvar);
5519 lhsc.var = get_vi_for_tree (t)->id;
5522 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5523 rhsc.type = ADDRESSOF;
5525 process_constraint (new_constraint (lhsc, rhsc));
5526 vi->is_restrict_var = 1;
5530 for (p = get_vi_for_tree (t); p; p = p->next)
5532 if (p->may_have_pointers)
5533 make_constraint_from (p, nonlocal_id);
5534 if (p->only_restrict_pointers)
5535 make_constraint_from_restrict (p, "PARM_RESTRICT");
5537 if (POINTER_TYPE_P (TREE_TYPE (t))
5538 && TYPE_RESTRICT (TREE_TYPE (t)))
5539 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5542 /* Add a constraint for a result decl that is passed by reference. */
5543 if (DECL_RESULT (cfun->decl)
5544 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5546 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5548 for (p = result_vi; p; p = p->next)
5549 make_constraint_from (p, nonlocal_id);
5552 /* Add a constraint for the incoming static chain parameter. */
5553 if (cfun->static_chain_decl != NULL_TREE)
5555 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5557 for (p = chain_vi; p; p = p->next)
5558 make_constraint_from (p, nonlocal_id);
5562 /* Structure used to put solution bitmaps in a hashtable so they can
5563 be shared among variables with the same points-to set. */
5565 typedef struct shared_bitmap_info
5569 } *shared_bitmap_info_t;
5570 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5572 static htab_t shared_bitmap_table;
5574 /* Hash function for a shared_bitmap_info_t */
5577 shared_bitmap_hash (const void *p)
5579 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5580 return bi->hashcode;
5583 /* Equality function for two shared_bitmap_info_t's. */
5586 shared_bitmap_eq (const void *p1, const void *p2)
5588 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5589 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5590 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5593 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5594 existing instance if there is one, NULL otherwise. */
5597 shared_bitmap_lookup (bitmap pt_vars)
5600 struct shared_bitmap_info sbi;
5602 sbi.pt_vars = pt_vars;
5603 sbi.hashcode = bitmap_hash (pt_vars);
5605 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5606 sbi.hashcode, NO_INSERT);
5610 return ((shared_bitmap_info_t) *slot)->pt_vars;
5614 /* Add a bitmap to the shared bitmap hashtable. */
5617 shared_bitmap_add (bitmap pt_vars)
5620 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5622 sbi->pt_vars = pt_vars;
5623 sbi->hashcode = bitmap_hash (pt_vars);
5625 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5626 sbi->hashcode, INSERT);
5627 gcc_assert (!*slot);
5628 *slot = (void *) sbi;
5632 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5635 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5640 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5642 varinfo_t vi = get_varinfo (i);
5644 /* The only artificial variables that are allowed in a may-alias
5645 set are heap variables. */
5646 if (vi->is_artificial_var && !vi->is_heap_var)
5649 if (TREE_CODE (vi->decl) == VAR_DECL
5650 || TREE_CODE (vi->decl) == PARM_DECL
5651 || TREE_CODE (vi->decl) == RESULT_DECL)
5653 /* If we are in IPA mode we will not recompute points-to
5654 sets after inlining so make sure they stay valid. */
5656 && !DECL_PT_UID_SET_P (vi->decl))
5657 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5659 /* Add the decl to the points-to set. Note that the points-to
5660 set contains global variables. */
5661 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5662 if (vi->is_global_var)
5663 pt->vars_contains_global = true;
5669 /* Compute the points-to solution *PT for the variable VI. */
5672 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5676 bitmap finished_solution;
5680 memset (pt, 0, sizeof (struct pt_solution));
5682 /* This variable may have been collapsed, let's get the real
5684 vi = get_varinfo (find (orig_vi->id));
5686 /* Translate artificial variables into SSA_NAME_PTR_INFO
5688 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5690 varinfo_t vi = get_varinfo (i);
5692 if (vi->is_artificial_var)
5694 if (vi->id == nothing_id)
5696 else if (vi->id == escaped_id)
5699 pt->ipa_escaped = 1;
5703 else if (vi->id == nonlocal_id)
5705 else if (vi->is_heap_var)
5706 /* We represent heapvars in the points-to set properly. */
5708 else if (vi->id == readonly_id)
5711 else if (vi->id == anything_id
5712 || vi->id == integer_id)
5715 if (vi->is_restrict_var)
5716 pt->vars_contains_restrict = true;
5719 /* Instead of doing extra work, simply do not create
5720 elaborate points-to information for pt_anything pointers. */
5722 && (orig_vi->is_artificial_var
5723 || !pt->vars_contains_restrict))
5726 /* Share the final set of variables when possible. */
5727 finished_solution = BITMAP_GGC_ALLOC ();
5728 stats.points_to_sets_created++;
5730 set_uids_in_ptset (finished_solution, vi->solution, pt);
5731 result = shared_bitmap_lookup (finished_solution);
5734 shared_bitmap_add (finished_solution);
5735 pt->vars = finished_solution;
5740 bitmap_clear (finished_solution);
5744 /* Given a pointer variable P, fill in its points-to set. */
5747 find_what_p_points_to (tree p)
5749 struct ptr_info_def *pi;
5753 /* For parameters, get at the points-to set for the actual parm
5755 if (TREE_CODE (p) == SSA_NAME
5756 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5757 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5758 && SSA_NAME_IS_DEFAULT_DEF (p))
5759 lookup_p = SSA_NAME_VAR (p);
5761 vi = lookup_vi_for_tree (lookup_p);
5765 pi = get_ptr_info (p);
5766 find_what_var_points_to (vi, &pi->pt);
5770 /* Query statistics for points-to solutions. */
5773 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5774 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5775 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5776 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5780 dump_pta_stats (FILE *s)
5782 fprintf (s, "\nPTA query stats:\n");
5783 fprintf (s, " pt_solution_includes: "
5784 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5785 HOST_WIDE_INT_PRINT_DEC" queries\n",
5786 pta_stats.pt_solution_includes_no_alias,
5787 pta_stats.pt_solution_includes_no_alias
5788 + pta_stats.pt_solution_includes_may_alias);
5789 fprintf (s, " pt_solutions_intersect: "
5790 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5791 HOST_WIDE_INT_PRINT_DEC" queries\n",
5792 pta_stats.pt_solutions_intersect_no_alias,
5793 pta_stats.pt_solutions_intersect_no_alias
5794 + pta_stats.pt_solutions_intersect_may_alias);
5798 /* Reset the points-to solution *PT to a conservative default
5799 (point to anything). */
5802 pt_solution_reset (struct pt_solution *pt)
5804 memset (pt, 0, sizeof (struct pt_solution));
5805 pt->anything = true;
5808 /* Set the points-to solution *PT to point only to the variables
5809 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5810 global variables and VARS_CONTAINS_RESTRICT specifies whether
5811 it contains restrict tag variables. */
5814 pt_solution_set (struct pt_solution *pt, bitmap vars,
5815 bool vars_contains_global, bool vars_contains_restrict)
5817 memset (pt, 0, sizeof (struct pt_solution));
5819 pt->vars_contains_global = vars_contains_global;
5820 pt->vars_contains_restrict = vars_contains_restrict;
5823 /* Set the points-to solution *PT to point only to the variable VAR. */
5826 pt_solution_set_var (struct pt_solution *pt, tree var)
5828 memset (pt, 0, sizeof (struct pt_solution));
5829 pt->vars = BITMAP_GGC_ALLOC ();
5830 bitmap_set_bit (pt->vars, DECL_UID (var));
5831 pt->vars_contains_global = is_global_var (var);
5834 /* Computes the union of the points-to solutions *DEST and *SRC and
5835 stores the result in *DEST. This changes the points-to bitmap
5836 of *DEST and thus may not be used if that might be shared.
5837 The points-to bitmap of *SRC and *DEST will not be shared after
5838 this function if they were not before. */
5841 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5843 dest->anything |= src->anything;
5846 pt_solution_reset (dest);
5850 dest->nonlocal |= src->nonlocal;
5851 dest->escaped |= src->escaped;
5852 dest->ipa_escaped |= src->ipa_escaped;
5853 dest->null |= src->null;
5854 dest->vars_contains_global |= src->vars_contains_global;
5855 dest->vars_contains_restrict |= src->vars_contains_restrict;
5860 dest->vars = BITMAP_GGC_ALLOC ();
5861 bitmap_ior_into (dest->vars, src->vars);
5864 /* Return true if the points-to solution *PT is empty. */
5867 pt_solution_empty_p (struct pt_solution *pt)
5874 && !bitmap_empty_p (pt->vars))
5877 /* If the solution includes ESCAPED, check if that is empty. */
5879 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5882 /* If the solution includes ESCAPED, check if that is empty. */
5884 && !pt_solution_empty_p (&ipa_escaped_pt))
5890 /* Return true if the points-to solution *PT includes global memory. */
5893 pt_solution_includes_global (struct pt_solution *pt)
5897 || pt->vars_contains_global)
5901 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5903 if (pt->ipa_escaped)
5904 return pt_solution_includes_global (&ipa_escaped_pt);
5906 /* ??? This predicate is not correct for the IPA-PTA solution
5907 as we do not properly distinguish between unit escape points
5908 and global variables. */
5909 if (cfun->gimple_df->ipa_pta)
5915 /* Return true if the points-to solution *PT includes the variable
5916 declaration DECL. */
5919 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5925 && is_global_var (decl))
5929 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5932 /* If the solution includes ESCAPED, check it. */
5934 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5937 /* If the solution includes ESCAPED, check it. */
5939 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5946 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5948 bool res = pt_solution_includes_1 (pt, decl);
5950 ++pta_stats.pt_solution_includes_may_alias;
5952 ++pta_stats.pt_solution_includes_no_alias;
5956 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5960 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5962 if (pt1->anything || pt2->anything)
5965 /* If either points to unknown global memory and the other points to
5966 any global memory they alias. */
5969 || pt2->vars_contains_global))
5971 && pt1->vars_contains_global))
5974 /* Check the escaped solution if required. */
5975 if ((pt1->escaped || pt2->escaped)
5976 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5978 /* If both point to escaped memory and that solution
5979 is not empty they alias. */
5980 if (pt1->escaped && pt2->escaped)
5983 /* If either points to escaped memory see if the escaped solution
5984 intersects with the other. */
5986 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5988 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
5992 /* Check the escaped solution if required.
5993 ??? Do we need to check the local against the IPA escaped sets? */
5994 if ((pt1->ipa_escaped || pt2->ipa_escaped)
5995 && !pt_solution_empty_p (&ipa_escaped_pt))
5997 /* If both point to escaped memory and that solution
5998 is not empty they alias. */
5999 if (pt1->ipa_escaped && pt2->ipa_escaped)
6002 /* If either points to escaped memory see if the escaped solution
6003 intersects with the other. */
6004 if ((pt1->ipa_escaped
6005 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6006 || (pt2->ipa_escaped
6007 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6011 /* Now both pointers alias if their points-to solution intersects. */
6014 && bitmap_intersect_p (pt1->vars, pt2->vars));
6018 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6020 bool res = pt_solutions_intersect_1 (pt1, pt2);
6022 ++pta_stats.pt_solutions_intersect_may_alias;
6024 ++pta_stats.pt_solutions_intersect_no_alias;
6028 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6029 qualified pointers are possibly based on the same pointer. */
6032 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6033 struct pt_solution *pt2)
6035 /* If we deal with points-to solutions of two restrict qualified
6036 pointers solely rely on the pointed-to variable bitmap intersection.
6037 For two pointers that are based on each other the bitmaps will
6039 if (pt1->vars_contains_restrict
6040 && pt2->vars_contains_restrict)
6042 gcc_assert (pt1->vars && pt2->vars);
6043 return bitmap_intersect_p (pt1->vars, pt2->vars);
6050 /* Dump points-to information to OUTFILE. */
6053 dump_sa_points_to_info (FILE *outfile)
6057 fprintf (outfile, "\nPoints-to sets\n\n");
6059 if (dump_flags & TDF_STATS)
6061 fprintf (outfile, "Stats:\n");
6062 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6063 fprintf (outfile, "Non-pointer vars: %d\n",
6064 stats.nonpointer_vars);
6065 fprintf (outfile, "Statically unified vars: %d\n",
6066 stats.unified_vars_static);
6067 fprintf (outfile, "Dynamically unified vars: %d\n",
6068 stats.unified_vars_dynamic);
6069 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6070 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6071 fprintf (outfile, "Number of implicit edges: %d\n",
6072 stats.num_implicit_edges);
6075 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6077 varinfo_t vi = get_varinfo (i);
6078 if (!vi->may_have_pointers)
6080 dump_solution_for_var (outfile, i);
6085 /* Debug points-to information to stderr. */
6088 debug_sa_points_to_info (void)
6090 dump_sa_points_to_info (stderr);
6094 /* Initialize the always-existing constraint variables for NULL
6095 ANYTHING, READONLY, and INTEGER */
6098 init_base_vars (void)
6100 struct constraint_expr lhs, rhs;
6101 varinfo_t var_anything;
6102 varinfo_t var_nothing;
6103 varinfo_t var_readonly;
6104 varinfo_t var_escaped;
6105 varinfo_t var_nonlocal;
6106 varinfo_t var_storedanything;
6107 varinfo_t var_integer;
6109 /* Create the NULL variable, used to represent that a variable points
6111 var_nothing = new_var_info (NULL_TREE, "NULL");
6112 gcc_assert (var_nothing->id == nothing_id);
6113 var_nothing->is_artificial_var = 1;
6114 var_nothing->offset = 0;
6115 var_nothing->size = ~0;
6116 var_nothing->fullsize = ~0;
6117 var_nothing->is_special_var = 1;
6118 var_nothing->may_have_pointers = 0;
6119 var_nothing->is_global_var = 0;
6121 /* Create the ANYTHING variable, used to represent that a variable
6122 points to some unknown piece of memory. */
6123 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6124 gcc_assert (var_anything->id == anything_id);
6125 var_anything->is_artificial_var = 1;
6126 var_anything->size = ~0;
6127 var_anything->offset = 0;
6128 var_anything->next = NULL;
6129 var_anything->fullsize = ~0;
6130 var_anything->is_special_var = 1;
6132 /* Anything points to anything. This makes deref constraints just
6133 work in the presence of linked list and other p = *p type loops,
6134 by saying that *ANYTHING = ANYTHING. */
6136 lhs.var = anything_id;
6138 rhs.type = ADDRESSOF;
6139 rhs.var = anything_id;
6142 /* This specifically does not use process_constraint because
6143 process_constraint ignores all anything = anything constraints, since all
6144 but this one are redundant. */
6145 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6147 /* Create the READONLY variable, used to represent that a variable
6148 points to readonly memory. */
6149 var_readonly = new_var_info (NULL_TREE, "READONLY");
6150 gcc_assert (var_readonly->id == readonly_id);
6151 var_readonly->is_artificial_var = 1;
6152 var_readonly->offset = 0;
6153 var_readonly->size = ~0;
6154 var_readonly->fullsize = ~0;
6155 var_readonly->next = NULL;
6156 var_readonly->is_special_var = 1;
6158 /* readonly memory points to anything, in order to make deref
6159 easier. In reality, it points to anything the particular
6160 readonly variable can point to, but we don't track this
6163 lhs.var = readonly_id;
6165 rhs.type = ADDRESSOF;
6166 rhs.var = readonly_id; /* FIXME */
6168 process_constraint (new_constraint (lhs, rhs));
6170 /* Create the ESCAPED variable, used to represent the set of escaped
6172 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6173 gcc_assert (var_escaped->id == escaped_id);
6174 var_escaped->is_artificial_var = 1;
6175 var_escaped->offset = 0;
6176 var_escaped->size = ~0;
6177 var_escaped->fullsize = ~0;
6178 var_escaped->is_special_var = 0;
6180 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6182 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6183 gcc_assert (var_nonlocal->id == nonlocal_id);
6184 var_nonlocal->is_artificial_var = 1;
6185 var_nonlocal->offset = 0;
6186 var_nonlocal->size = ~0;
6187 var_nonlocal->fullsize = ~0;
6188 var_nonlocal->is_special_var = 1;
6190 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6192 lhs.var = escaped_id;
6195 rhs.var = escaped_id;
6197 process_constraint (new_constraint (lhs, rhs));
6199 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6200 whole variable escapes. */
6202 lhs.var = escaped_id;
6205 rhs.var = escaped_id;
6206 rhs.offset = UNKNOWN_OFFSET;
6207 process_constraint (new_constraint (lhs, rhs));
6209 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6210 everything pointed to by escaped points to what global memory can
6213 lhs.var = escaped_id;
6216 rhs.var = nonlocal_id;
6218 process_constraint (new_constraint (lhs, rhs));
6220 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6221 global memory may point to global memory and escaped memory. */
6223 lhs.var = nonlocal_id;
6225 rhs.type = ADDRESSOF;
6226 rhs.var = nonlocal_id;
6228 process_constraint (new_constraint (lhs, rhs));
6229 rhs.type = ADDRESSOF;
6230 rhs.var = escaped_id;
6232 process_constraint (new_constraint (lhs, rhs));
6234 /* Create the STOREDANYTHING variable, used to represent the set of
6235 variables stored to *ANYTHING. */
6236 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6237 gcc_assert (var_storedanything->id == storedanything_id);
6238 var_storedanything->is_artificial_var = 1;
6239 var_storedanything->offset = 0;
6240 var_storedanything->size = ~0;
6241 var_storedanything->fullsize = ~0;
6242 var_storedanything->is_special_var = 0;
6244 /* Create the INTEGER variable, used to represent that a variable points
6245 to what an INTEGER "points to". */
6246 var_integer = new_var_info (NULL_TREE, "INTEGER");
6247 gcc_assert (var_integer->id == integer_id);
6248 var_integer->is_artificial_var = 1;
6249 var_integer->size = ~0;
6250 var_integer->fullsize = ~0;
6251 var_integer->offset = 0;
6252 var_integer->next = NULL;
6253 var_integer->is_special_var = 1;
6255 /* INTEGER = ANYTHING, because we don't know where a dereference of
6256 a random integer will point to. */
6258 lhs.var = integer_id;
6260 rhs.type = ADDRESSOF;
6261 rhs.var = anything_id;
6263 process_constraint (new_constraint (lhs, rhs));
6266 /* Initialize things necessary to perform PTA */
6269 init_alias_vars (void)
6271 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6273 bitmap_obstack_initialize (&pta_obstack);
6274 bitmap_obstack_initialize (&oldpta_obstack);
6275 bitmap_obstack_initialize (&predbitmap_obstack);
6277 constraint_pool = create_alloc_pool ("Constraint pool",
6278 sizeof (struct constraint), 30);
6279 variable_info_pool = create_alloc_pool ("Variable info pool",
6280 sizeof (struct variable_info), 30);
6281 constraints = VEC_alloc (constraint_t, heap, 8);
6282 varmap = VEC_alloc (varinfo_t, heap, 8);
6283 vi_for_tree = pointer_map_create ();
6284 call_stmt_vars = pointer_map_create ();
6286 memset (&stats, 0, sizeof (stats));
6287 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6288 shared_bitmap_eq, free);
6292 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6293 predecessor edges. */
6296 remove_preds_and_fake_succs (constraint_graph_t graph)
6300 /* Clear the implicit ref and address nodes from the successor
6302 for (i = 0; i < FIRST_REF_NODE; i++)
6304 if (graph->succs[i])
6305 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6306 FIRST_REF_NODE * 2);
6309 /* Free the successor list for the non-ref nodes. */
6310 for (i = FIRST_REF_NODE; i < graph->size; i++)
6312 if (graph->succs[i])
6313 BITMAP_FREE (graph->succs[i]);
6316 /* Now reallocate the size of the successor list as, and blow away
6317 the predecessor bitmaps. */
6318 graph->size = VEC_length (varinfo_t, varmap);
6319 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6321 free (graph->implicit_preds);
6322 graph->implicit_preds = NULL;
6323 free (graph->preds);
6324 graph->preds = NULL;
6325 bitmap_obstack_release (&predbitmap_obstack);
6328 /* Initialize the heapvar for statement mapping. */
6331 init_alias_heapvars (void)
6333 if (!heapvar_for_stmt)
6334 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6338 /* Delete the heapvar for statement mapping. */
6341 delete_alias_heapvars (void)
6343 if (heapvar_for_stmt)
6344 htab_delete (heapvar_for_stmt);
6345 heapvar_for_stmt = NULL;
6348 /* Solve the constraint set. */
6351 solve_constraints (void)
6353 struct scc_info *si;
6357 "\nCollapsing static cycles and doing variable "
6360 init_graph (VEC_length (varinfo_t, varmap) * 2);
6363 fprintf (dump_file, "Building predecessor graph\n");
6364 build_pred_graph ();
6367 fprintf (dump_file, "Detecting pointer and location "
6369 si = perform_var_substitution (graph);
6372 fprintf (dump_file, "Rewriting constraints and unifying "
6374 rewrite_constraints (graph, si);
6376 build_succ_graph ();
6377 free_var_substitution_info (si);
6379 if (dump_file && (dump_flags & TDF_GRAPH))
6380 dump_constraint_graph (dump_file);
6382 move_complex_constraints (graph);
6385 fprintf (dump_file, "Uniting pointer but not location equivalent "
6387 unite_pointer_equivalences (graph);
6390 fprintf (dump_file, "Finding indirect cycles\n");
6391 find_indirect_cycles (graph);
6393 /* Implicit nodes and predecessors are no longer necessary at this
6395 remove_preds_and_fake_succs (graph);
6398 fprintf (dump_file, "Solving graph\n");
6400 solve_graph (graph);
6403 dump_sa_points_to_info (dump_file);
6406 /* Create points-to sets for the current function. See the comments
6407 at the start of the file for an algorithmic overview. */
6410 compute_points_to_sets (void)
6416 timevar_push (TV_TREE_PTA);
6419 init_alias_heapvars ();
6421 intra_create_variable_infos ();
6423 /* Now walk all statements and build the constraint set. */
6426 gimple_stmt_iterator gsi;
6428 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6430 gimple phi = gsi_stmt (gsi);
6432 if (is_gimple_reg (gimple_phi_result (phi)))
6433 find_func_aliases (phi);
6436 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6438 gimple stmt = gsi_stmt (gsi);
6440 find_func_aliases (stmt);
6446 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6447 dump_constraints (dump_file, 0);
6450 /* From the constraints compute the points-to sets. */
6451 solve_constraints ();
6453 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6454 find_what_var_points_to (get_varinfo (escaped_id),
6455 &cfun->gimple_df->escaped);
6457 /* Make sure the ESCAPED solution (which is used as placeholder in
6458 other solutions) does not reference itself. This simplifies
6459 points-to solution queries. */
6460 cfun->gimple_df->escaped.escaped = 0;
6462 /* Mark escaped HEAP variables as global. */
6463 for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); ++i)
6465 && !vi->is_restrict_var
6466 && !vi->is_global_var)
6467 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6468 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6470 /* Compute the points-to sets for pointer SSA_NAMEs. */
6471 for (i = 0; i < num_ssa_names; ++i)
6473 tree ptr = ssa_name (i);
6475 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6476 find_what_p_points_to (ptr);
6479 /* Compute the call-used/clobbered sets. */
6482 gimple_stmt_iterator gsi;
6484 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6486 gimple stmt = gsi_stmt (gsi);
6487 struct pt_solution *pt;
6488 if (!is_gimple_call (stmt))
6491 pt = gimple_call_use_set (stmt);
6492 if (gimple_call_flags (stmt) & ECF_CONST)
6493 memset (pt, 0, sizeof (struct pt_solution));
6494 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6496 find_what_var_points_to (vi, pt);
6497 /* Escaped (and thus nonlocal) variables are always
6498 implicitly used by calls. */
6499 /* ??? ESCAPED can be empty even though NONLOCAL
6506 /* If there is nothing special about this call then
6507 we have made everything that is used also escape. */
6508 *pt = cfun->gimple_df->escaped;
6512 pt = gimple_call_clobber_set (stmt);
6513 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6514 memset (pt, 0, sizeof (struct pt_solution));
6515 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6517 find_what_var_points_to (vi, pt);
6518 /* Escaped (and thus nonlocal) variables are always
6519 implicitly clobbered by calls. */
6520 /* ??? ESCAPED can be empty even though NONLOCAL
6527 /* If there is nothing special about this call then
6528 we have made everything that is used also escape. */
6529 *pt = cfun->gimple_df->escaped;
6535 timevar_pop (TV_TREE_PTA);
6539 /* Delete created points-to sets. */
6542 delete_points_to_sets (void)
6546 htab_delete (shared_bitmap_table);
6547 if (dump_file && (dump_flags & TDF_STATS))
6548 fprintf (dump_file, "Points to sets created:%d\n",
6549 stats.points_to_sets_created);
6551 pointer_map_destroy (vi_for_tree);
6552 pointer_map_destroy (call_stmt_vars);
6553 bitmap_obstack_release (&pta_obstack);
6554 VEC_free (constraint_t, heap, constraints);
6556 for (i = 0; i < graph->size; i++)
6557 VEC_free (constraint_t, heap, graph->complex[i]);
6558 free (graph->complex);
6561 free (graph->succs);
6563 free (graph->pe_rep);
6564 free (graph->indirect_cycles);
6567 VEC_free (varinfo_t, heap, varmap);
6568 free_alloc_pool (variable_info_pool);
6569 free_alloc_pool (constraint_pool);
6573 /* Compute points-to information for every SSA_NAME pointer in the
6574 current function and compute the transitive closure of escaped
6575 variables to re-initialize the call-clobber states of local variables. */
6578 compute_may_aliases (void)
6580 if (cfun->gimple_df->ipa_pta)
6584 fprintf (dump_file, "\nNot re-computing points-to information "
6585 "because IPA points-to information is available.\n\n");
6587 /* But still dump what we have remaining it. */
6588 dump_alias_info (dump_file);
6590 if (dump_flags & TDF_DETAILS)
6591 dump_referenced_vars (dump_file);
6597 /* For each pointer P_i, determine the sets of variables that P_i may
6598 point-to. Compute the reachability set of escaped and call-used
6600 compute_points_to_sets ();
6602 /* Debugging dumps. */
6605 dump_alias_info (dump_file);
6607 if (dump_flags & TDF_DETAILS)
6608 dump_referenced_vars (dump_file);
6611 /* Deallocate memory used by aliasing data structures and the internal
6612 points-to solution. */
6613 delete_points_to_sets ();
6615 gcc_assert (!need_ssa_update_p (cfun));
6621 gate_tree_pta (void)
6623 return flag_tree_pta;
6626 /* A dummy pass to cause points-to information to be computed via
6627 TODO_rebuild_alias. */
6629 struct gimple_opt_pass pass_build_alias =
6634 gate_tree_pta, /* gate */
6638 0, /* static_pass_number */
6639 TV_NONE, /* tv_id */
6640 PROP_cfg | PROP_ssa, /* properties_required */
6641 0, /* properties_provided */
6642 0, /* properties_destroyed */
6643 0, /* todo_flags_start */
6644 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6648 /* A dummy pass to cause points-to information to be computed via
6649 TODO_rebuild_alias. */
6651 struct gimple_opt_pass pass_build_ealias =
6655 "ealias", /* name */
6656 gate_tree_pta, /* gate */
6660 0, /* static_pass_number */
6661 TV_NONE, /* tv_id */
6662 PROP_cfg | PROP_ssa, /* properties_required */
6663 0, /* properties_provided */
6664 0, /* properties_destroyed */
6665 0, /* todo_flags_start */
6666 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6671 /* Return true if we should execute IPA PTA. */
6677 /* Don't bother doing anything if the program has errors. */
6681 /* IPA PTA solutions for ESCAPED. */
6682 struct pt_solution ipa_escaped_pt
6683 = { true, false, false, false, false, false, false, NULL };
6685 /* Execute the driver for IPA PTA. */
6687 ipa_pta_execute (void)
6689 struct cgraph_node *node;
6690 struct varpool_node *var;
6695 init_alias_heapvars ();
6698 /* Build the constraints. */
6699 for (node = cgraph_nodes; node; node = node->next)
6701 struct cgraph_node *alias;
6704 /* Nodes without a body are not interesting. Especially do not
6705 visit clones at this point for now - we get duplicate decls
6706 there for inline clones at least. */
6707 if (!gimple_has_body_p (node->decl)
6711 vi = create_function_info_for (node->decl,
6712 alias_get_name (node->decl));
6714 /* Associate the varinfo node with all aliases. */
6715 for (alias = node->same_body; alias; alias = alias->next)
6716 insert_vi_for_tree (alias->decl, vi);
6719 /* Create constraints for global variables and their initializers. */
6720 for (var = varpool_nodes; var; var = var->next)
6722 struct varpool_node *alias;
6725 vi = get_vi_for_tree (var->decl);
6727 /* Associate the varinfo node with all aliases. */
6728 for (alias = var->extra_name; alias; alias = alias->next)
6729 insert_vi_for_tree (alias->decl, vi);
6735 "Generating constraints for global initializers\n\n");
6736 dump_constraints (dump_file, 0);
6737 fprintf (dump_file, "\n");
6739 from = VEC_length (constraint_t, constraints);
6741 for (node = cgraph_nodes; node; node = node->next)
6743 struct function *func;
6747 /* Nodes without a body are not interesting. */
6748 if (!gimple_has_body_p (node->decl)
6755 "Generating constraints for %s", cgraph_node_name (node));
6756 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6757 fprintf (dump_file, " (%s)",
6758 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6759 fprintf (dump_file, "\n");
6762 func = DECL_STRUCT_FUNCTION (node->decl);
6763 old_func_decl = current_function_decl;
6765 current_function_decl = node->decl;
6767 /* For externally visible functions use local constraints for
6768 their arguments. For local functions we see all callers
6769 and thus do not need initial constraints for parameters. */
6770 if (node->local.externally_visible)
6771 intra_create_variable_infos ();
6773 /* Build constriants for the function body. */
6774 FOR_EACH_BB_FN (bb, func)
6776 gimple_stmt_iterator gsi;
6778 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6781 gimple phi = gsi_stmt (gsi);
6783 if (is_gimple_reg (gimple_phi_result (phi)))
6784 find_func_aliases (phi);
6787 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6789 gimple stmt = gsi_stmt (gsi);
6791 find_func_aliases (stmt);
6792 find_func_clobbers (stmt);
6796 current_function_decl = old_func_decl;
6801 fprintf (dump_file, "\n");
6802 dump_constraints (dump_file, from);
6803 fprintf (dump_file, "\n");
6805 from = VEC_length (constraint_t, constraints);
6808 /* From the constraints compute the points-to sets. */
6809 solve_constraints ();
6811 /* Compute the global points-to sets for ESCAPED.
6812 ??? Note that the computed escape set is not correct
6813 for the whole unit as we fail to consider graph edges to
6814 externally visible functions. */
6815 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6817 /* Make sure the ESCAPED solution (which is used as placeholder in
6818 other solutions) does not reference itself. This simplifies
6819 points-to solution queries. */
6820 ipa_escaped_pt.ipa_escaped = 0;
6822 /* Assign the points-to sets to the SSA names in the unit. */
6823 for (node = cgraph_nodes; node; node = node->next)
6826 struct function *fn;
6830 struct pt_solution uses, clobbers;
6831 struct cgraph_edge *e;
6833 /* Nodes without a body are not interesting. */
6834 if (!gimple_has_body_p (node->decl)
6838 fn = DECL_STRUCT_FUNCTION (node->decl);
6840 /* Compute the points-to sets for pointer SSA_NAMEs. */
6841 for (i = 0; VEC_iterate (tree, fn->gimple_df->ssa_names, i, ptr); ++i)
6844 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6845 find_what_p_points_to (ptr);
6848 /* Compute the call-use and call-clobber sets for all direct calls. */
6849 fi = lookup_vi_for_tree (node->decl);
6850 gcc_assert (fi->is_fn_info);
6851 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6853 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6854 for (e = node->callers; e; e = e->next_caller)
6859 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6860 *gimple_call_use_set (e->call_stmt) = uses;
6863 /* Compute the call-use and call-clobber sets for indirect calls
6864 and calls to external functions. */
6865 FOR_EACH_BB_FN (bb, fn)
6867 gimple_stmt_iterator gsi;
6869 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6871 gimple stmt = gsi_stmt (gsi);
6872 struct pt_solution *pt;
6876 if (!is_gimple_call (stmt))
6879 /* Handle direct calls to external functions. */
6880 decl = gimple_call_fndecl (stmt);
6882 && (!(fi = lookup_vi_for_tree (decl))
6883 || !fi->is_fn_info))
6885 pt = gimple_call_use_set (stmt);
6886 if (gimple_call_flags (stmt) & ECF_CONST)
6887 memset (pt, 0, sizeof (struct pt_solution));
6888 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6890 find_what_var_points_to (vi, pt);
6891 /* Escaped (and thus nonlocal) variables are always
6892 implicitly used by calls. */
6893 /* ??? ESCAPED can be empty even though NONLOCAL
6896 pt->ipa_escaped = 1;
6900 /* If there is nothing special about this call then
6901 we have made everything that is used also escape. */
6902 *pt = ipa_escaped_pt;
6906 pt = gimple_call_clobber_set (stmt);
6907 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6908 memset (pt, 0, sizeof (struct pt_solution));
6909 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6911 find_what_var_points_to (vi, pt);
6912 /* Escaped (and thus nonlocal) variables are always
6913 implicitly clobbered by calls. */
6914 /* ??? ESCAPED can be empty even though NONLOCAL
6917 pt->ipa_escaped = 1;
6921 /* If there is nothing special about this call then
6922 we have made everything that is used also escape. */
6923 *pt = ipa_escaped_pt;
6928 /* Handle indirect calls. */
6930 && (fi = get_fi_for_callee (stmt)))
6932 /* We need to accumulate all clobbers/uses of all possible
6934 fi = get_varinfo (find (fi->id));
6935 /* If we cannot constrain the set of functions we'll end up
6936 calling we end up using/clobbering everything. */
6937 if (bitmap_bit_p (fi->solution, anything_id)
6938 || bitmap_bit_p (fi->solution, nonlocal_id)
6939 || bitmap_bit_p (fi->solution, escaped_id))
6941 pt_solution_reset (gimple_call_clobber_set (stmt));
6942 pt_solution_reset (gimple_call_use_set (stmt));
6948 struct pt_solution *uses, *clobbers;
6950 uses = gimple_call_use_set (stmt);
6951 clobbers = gimple_call_clobber_set (stmt);
6952 memset (uses, 0, sizeof (struct pt_solution));
6953 memset (clobbers, 0, sizeof (struct pt_solution));
6954 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6956 struct pt_solution sol;
6958 vi = get_varinfo (i);
6959 if (!vi->is_fn_info)
6961 /* ??? We could be more precise here? */
6963 uses->ipa_escaped = 1;
6964 clobbers->nonlocal = 1;
6965 clobbers->ipa_escaped = 1;
6969 if (!uses->anything)
6971 find_what_var_points_to
6972 (first_vi_for_offset (vi, fi_uses), &sol);
6973 pt_solution_ior_into (uses, &sol);
6975 if (!clobbers->anything)
6977 find_what_var_points_to
6978 (first_vi_for_offset (vi, fi_clobbers), &sol);
6979 pt_solution_ior_into (clobbers, &sol);
6987 fn->gimple_df->ipa_pta = true;
6990 delete_points_to_sets ();
6997 struct simple_ipa_opt_pass pass_ipa_pta =
7002 gate_ipa_pta, /* gate */
7003 ipa_pta_execute, /* execute */
7006 0, /* static_pass_number */
7007 TV_IPA_PTA, /* tv_id */
7008 0, /* properties_required */
7009 0, /* properties_provided */
7010 0, /* properties_destroyed */
7011 0, /* todo_flags_start */
7012 TODO_update_ssa /* todo_flags_finish */
7017 #include "gt-tree-ssa-structalias.h"