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. */
201 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
202 htab_t heapvar_for_stmt;
204 static bool use_field_sensitive = true;
205 static int in_ipa_mode = 0;
207 /* Used for predecessor bitmaps. */
208 static bitmap_obstack predbitmap_obstack;
210 /* Used for points-to sets. */
211 static bitmap_obstack pta_obstack;
213 /* Used for oldsolution members of variables. */
214 static bitmap_obstack oldpta_obstack;
216 /* Used for per-solver-iteration bitmaps. */
217 static bitmap_obstack iteration_obstack;
219 static unsigned int create_variable_info_for (tree, const char *);
220 typedef struct constraint_graph *constraint_graph_t;
221 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
224 typedef struct constraint *constraint_t;
226 DEF_VEC_P(constraint_t);
227 DEF_VEC_ALLOC_P(constraint_t,heap);
229 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
231 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
233 static struct constraint_stats
235 unsigned int total_vars;
236 unsigned int nonpointer_vars;
237 unsigned int unified_vars_static;
238 unsigned int unified_vars_dynamic;
239 unsigned int iterations;
240 unsigned int num_edges;
241 unsigned int num_implicit_edges;
242 unsigned int points_to_sets_created;
247 /* ID of this variable */
250 /* True if this is a variable created by the constraint analysis, such as
251 heap variables and constraints we had to break up. */
252 unsigned int is_artificial_var : 1;
254 /* True if this is a special variable whose solution set should not be
256 unsigned int is_special_var : 1;
258 /* True for variables whose size is not known or variable. */
259 unsigned int is_unknown_size_var : 1;
261 /* True for (sub-)fields that represent a whole variable. */
262 unsigned int is_full_var : 1;
264 /* True if this is a heap variable. */
265 unsigned int is_heap_var : 1;
267 /* True if this is a variable tracking a restrict pointer source. */
268 unsigned int is_restrict_var : 1;
270 /* True if this field may contain pointers. */
271 unsigned int may_have_pointers : 1;
273 /* True if this field has only restrict qualified pointers. */
274 unsigned int only_restrict_pointers : 1;
276 /* True if this represents a global variable. */
277 unsigned int is_global_var : 1;
279 /* True if this represents a IPA function info. */
280 unsigned int is_fn_info : 1;
282 /* A link to the variable for the next field in this structure. */
283 struct variable_info *next;
285 /* Offset of this variable, in bits, from the base variable */
286 unsigned HOST_WIDE_INT offset;
288 /* Size of the variable, in bits. */
289 unsigned HOST_WIDE_INT size;
291 /* Full size of the base variable, in bits. */
292 unsigned HOST_WIDE_INT fullsize;
294 /* Name of this variable */
297 /* Tree that this variable is associated with. */
300 /* Points-to set for this variable. */
303 /* Old points-to set for this variable. */
306 typedef struct variable_info *varinfo_t;
308 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
309 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
310 unsigned HOST_WIDE_INT);
311 static varinfo_t lookup_vi_for_tree (tree);
313 /* Pool of variable info structures. */
314 static alloc_pool variable_info_pool;
316 DEF_VEC_P(varinfo_t);
318 DEF_VEC_ALLOC_P(varinfo_t, heap);
320 /* Table of variable info structures for constraint variables.
321 Indexed directly by variable info id. */
322 static VEC(varinfo_t,heap) *varmap;
324 /* Return the varmap element N */
326 static inline varinfo_t
327 get_varinfo (unsigned int n)
329 return VEC_index (varinfo_t, varmap, n);
332 /* Static IDs for the special variables. */
333 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
334 escaped_id = 3, nonlocal_id = 4,
335 storedanything_id = 5, integer_id = 6 };
337 struct GTY(()) heapvar_map {
339 unsigned HOST_WIDE_INT offset;
343 heapvar_map_eq (const void *p1, const void *p2)
345 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
346 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
347 return (h1->map.base.from == h2->map.base.from
348 && h1->offset == h2->offset);
352 heapvar_map_hash (struct heapvar_map *h)
354 return iterative_hash_host_wide_int (h->offset,
355 htab_hash_pointer (h->map.base.from));
358 /* Lookup a heap var for FROM, and return it if we find one. */
361 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
363 struct heapvar_map *h, in;
364 in.map.base.from = from;
366 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
367 heapvar_map_hash (&in));
373 /* Insert a mapping FROM->TO in the heap var for statement
377 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
379 struct heapvar_map *h;
382 h = GGC_NEW (struct heapvar_map);
383 h->map.base.from = from;
385 h->map.hash = heapvar_map_hash (h);
387 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
388 gcc_assert (*loc == NULL);
389 *(struct heapvar_map **) loc = h;
392 /* Return a new variable info structure consisting for a variable
393 named NAME, and using constraint graph node NODE. Append it
394 to the vector of variable info structures. */
397 new_var_info (tree t, const char *name)
399 unsigned index = VEC_length (varinfo_t, varmap);
400 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
405 /* Vars without decl are artificial and do not have sub-variables. */
406 ret->is_artificial_var = (t == NULL_TREE);
407 ret->is_special_var = false;
408 ret->is_unknown_size_var = false;
409 ret->is_full_var = (t == NULL_TREE);
410 ret->is_heap_var = false;
411 ret->is_restrict_var = false;
412 ret->may_have_pointers = true;
413 ret->only_restrict_pointers = false;
414 ret->is_global_var = (t == NULL_TREE);
415 ret->is_fn_info = false;
417 ret->is_global_var = is_global_var (t);
418 ret->solution = BITMAP_ALLOC (&pta_obstack);
419 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
424 VEC_safe_push (varinfo_t, heap, varmap, ret);
430 /* A map mapping call statements to per-stmt variables for uses
431 and clobbers specific to the call. */
432 struct pointer_map_t *call_stmt_vars;
434 /* Lookup or create the variable for the call statement CALL. */
437 get_call_vi (gimple call)
442 slot_p = pointer_map_insert (call_stmt_vars, call);
444 return (varinfo_t) *slot_p;
446 vi = new_var_info (NULL_TREE, "CALLUSED");
450 vi->is_full_var = true;
452 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
456 vi2->is_full_var = true;
458 *slot_p = (void *) vi;
462 /* Lookup the variable for the call statement CALL representing
463 the uses. Returns NULL if there is nothing special about this call. */
466 lookup_call_use_vi (gimple call)
470 slot_p = pointer_map_contains (call_stmt_vars, call);
472 return (varinfo_t) *slot_p;
477 /* Lookup the variable for the call statement CALL representing
478 the clobbers. Returns NULL if there is nothing special about this call. */
481 lookup_call_clobber_vi (gimple call)
483 varinfo_t uses = lookup_call_use_vi (call);
490 /* Lookup or create the variable for the call statement CALL representing
494 get_call_use_vi (gimple call)
496 return get_call_vi (call);
499 /* Lookup or create the variable for the call statement CALL representing
502 static varinfo_t ATTRIBUTE_UNUSED
503 get_call_clobber_vi (gimple call)
505 return get_call_vi (call)->next;
509 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
511 /* An expression that appears in a constraint. */
513 struct constraint_expr
515 /* Constraint type. */
516 constraint_expr_type type;
518 /* Variable we are referring to in the constraint. */
521 /* Offset, in bits, of this constraint from the beginning of
522 variables it ends up referring to.
524 IOW, in a deref constraint, we would deref, get the result set,
525 then add OFFSET to each member. */
526 HOST_WIDE_INT offset;
529 /* Use 0x8000... as special unknown offset. */
530 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
532 typedef struct constraint_expr ce_s;
534 DEF_VEC_ALLOC_O(ce_s, heap);
535 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool);
536 static void get_constraint_for (tree, VEC(ce_s, heap) **);
537 static void do_deref (VEC (ce_s, heap) **);
539 /* Our set constraints are made up of two constraint expressions, one
542 As described in the introduction, our set constraints each represent an
543 operation between set valued variables.
547 struct constraint_expr lhs;
548 struct constraint_expr rhs;
551 /* List of constraints that we use to build the constraint graph from. */
553 static VEC(constraint_t,heap) *constraints;
554 static alloc_pool constraint_pool;
556 /* The constraint graph is represented as an array of bitmaps
557 containing successor nodes. */
559 struct constraint_graph
561 /* Size of this graph, which may be different than the number of
562 nodes in the variable map. */
565 /* Explicit successors of each node. */
568 /* Implicit predecessors of each node (Used for variable
570 bitmap *implicit_preds;
572 /* Explicit predecessors of each node (Used for variable substitution). */
575 /* Indirect cycle representatives, or -1 if the node has no indirect
577 int *indirect_cycles;
579 /* Representative node for a node. rep[a] == a unless the node has
583 /* Equivalence class representative for a label. This is used for
584 variable substitution. */
587 /* Pointer equivalence label for a node. All nodes with the same
588 pointer equivalence label can be unified together at some point
589 (either during constraint optimization or after the constraint
593 /* Pointer equivalence representative for a label. This is used to
594 handle nodes that are pointer equivalent but not location
595 equivalent. We can unite these once the addressof constraints
596 are transformed into initial points-to sets. */
599 /* Pointer equivalence label for each node, used during variable
601 unsigned int *pointer_label;
603 /* Location equivalence label for each node, used during location
604 equivalence finding. */
605 unsigned int *loc_label;
607 /* Pointed-by set for each node, used during location equivalence
608 finding. This is pointed-by rather than pointed-to, because it
609 is constructed using the predecessor graph. */
612 /* Points to sets for pointer equivalence. This is *not* the actual
613 points-to sets for nodes. */
616 /* Bitmap of nodes where the bit is set if the node is a direct
617 node. Used for variable substitution. */
618 sbitmap direct_nodes;
620 /* Bitmap of nodes where the bit is set if the node is address
621 taken. Used for variable substitution. */
622 bitmap address_taken;
624 /* Vector of complex constraints for each graph node. Complex
625 constraints are those involving dereferences or offsets that are
627 VEC(constraint_t,heap) **complex;
630 static constraint_graph_t graph;
632 /* During variable substitution and the offline version of indirect
633 cycle finding, we create nodes to represent dereferences and
634 address taken constraints. These represent where these start and
636 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
637 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
639 /* Return the representative node for NODE, if NODE has been unioned
641 This function performs path compression along the way to finding
642 the representative. */
645 find (unsigned int node)
647 gcc_assert (node < graph->size);
648 if (graph->rep[node] != node)
649 return graph->rep[node] = find (graph->rep[node]);
653 /* Union the TO and FROM nodes to the TO nodes.
654 Note that at some point in the future, we may want to do
655 union-by-rank, in which case we are going to have to return the
656 node we unified to. */
659 unite (unsigned int to, unsigned int from)
661 gcc_assert (to < graph->size && from < graph->size);
662 if (to != from && graph->rep[from] != to)
664 graph->rep[from] = to;
670 /* Create a new constraint consisting of LHS and RHS expressions. */
673 new_constraint (const struct constraint_expr lhs,
674 const struct constraint_expr rhs)
676 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
682 /* Print out constraint C to FILE. */
685 dump_constraint (FILE *file, constraint_t c)
687 if (c->lhs.type == ADDRESSOF)
689 else if (c->lhs.type == DEREF)
691 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
692 if (c->lhs.offset == UNKNOWN_OFFSET)
693 fprintf (file, " + UNKNOWN");
694 else if (c->lhs.offset != 0)
695 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
696 fprintf (file, " = ");
697 if (c->rhs.type == ADDRESSOF)
699 else if (c->rhs.type == DEREF)
701 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
702 if (c->rhs.offset == UNKNOWN_OFFSET)
703 fprintf (file, " + UNKNOWN");
704 else if (c->rhs.offset != 0)
705 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
706 fprintf (file, "\n");
710 void debug_constraint (constraint_t);
711 void debug_constraints (void);
712 void debug_constraint_graph (void);
713 void debug_solution_for_var (unsigned int);
714 void debug_sa_points_to_info (void);
716 /* Print out constraint C to stderr. */
719 debug_constraint (constraint_t c)
721 dump_constraint (stderr, c);
724 /* Print out all constraints to FILE */
727 dump_constraints (FILE *file, int from)
731 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
732 dump_constraint (file, c);
735 /* Print out all constraints to stderr. */
738 debug_constraints (void)
740 dump_constraints (stderr, 0);
743 /* Print out to FILE the edge in the constraint graph that is created by
744 constraint c. The edge may have a label, depending on the type of
745 constraint that it represents. If complex1, e.g: a = *b, then the label
746 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
747 complex with an offset, e.g: a = b + 8, then the label is "+".
748 Otherwise the edge has no label. */
751 dump_constraint_edge (FILE *file, constraint_t c)
753 if (c->rhs.type != ADDRESSOF)
755 const char *src = get_varinfo (c->rhs.var)->name;
756 const char *dst = get_varinfo (c->lhs.var)->name;
757 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
758 /* Due to preprocessing of constraints, instructions like *a = *b are
759 illegal; thus, we do not have to handle such cases. */
760 if (c->lhs.type == DEREF)
761 fprintf (file, " [ label=\"*=\" ] ;\n");
762 else if (c->rhs.type == DEREF)
763 fprintf (file, " [ label=\"=*\" ] ;\n");
766 /* We must check the case where the constraint is an offset.
767 In this case, it is treated as a complex constraint. */
768 if (c->rhs.offset != c->lhs.offset)
769 fprintf (file, " [ label=\"+\" ] ;\n");
771 fprintf (file, " ;\n");
776 /* Print the constraint graph in dot format. */
779 dump_constraint_graph (FILE *file)
781 unsigned int i=0, size;
784 /* Only print the graph if it has already been initialized: */
788 /* Print the constraints used to produce the constraint graph. The
789 constraints will be printed as comments in the dot file: */
790 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
791 dump_constraints (file, 0);
792 fprintf (file, "*/\n");
794 /* Prints the header of the dot file: */
795 fprintf (file, "\n\n// The constraint graph in dot format:\n");
796 fprintf (file, "strict digraph {\n");
797 fprintf (file, " node [\n shape = box\n ]\n");
798 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
799 fprintf (file, "\n // List of nodes in the constraint graph:\n");
801 /* The next lines print the nodes in the graph. In order to get the
802 number of nodes in the graph, we must choose the minimum between the
803 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
804 yet been initialized, then graph->size == 0, otherwise we must only
805 read nodes that have an entry in VEC (varinfo_t, varmap). */
806 size = VEC_length (varinfo_t, varmap);
807 size = size < graph->size ? size : graph->size;
808 for (i = 0; i < size; i++)
810 const char *name = get_varinfo (graph->rep[i])->name;
811 fprintf (file, " \"%s\" ;\n", name);
814 /* Go over the list of constraints printing the edges in the constraint
816 fprintf (file, "\n // The constraint edges:\n");
817 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
819 dump_constraint_edge (file, c);
821 /* Prints the tail of the dot file. By now, only the closing bracket. */
822 fprintf (file, "}\n\n\n");
825 /* Print out the constraint graph to stderr. */
828 debug_constraint_graph (void)
830 dump_constraint_graph (stderr);
835 The solver is a simple worklist solver, that works on the following
838 sbitmap changed_nodes = all zeroes;
840 For each node that is not already collapsed:
842 set bit in changed nodes
844 while (changed_count > 0)
846 compute topological ordering for constraint graph
848 find and collapse cycles in the constraint graph (updating
849 changed if necessary)
851 for each node (n) in the graph in topological order:
854 Process each complex constraint associated with the node,
855 updating changed if necessary.
857 For each outgoing edge from n, propagate the solution from n to
858 the destination of the edge, updating changed as necessary.
862 /* Return true if two constraint expressions A and B are equal. */
865 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
867 return a.type == b.type && a.var == b.var && a.offset == b.offset;
870 /* Return true if constraint expression A is less than constraint expression
871 B. This is just arbitrary, but consistent, in order to give them an
875 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
877 if (a.type == b.type)
880 return a.offset < b.offset;
882 return a.var < b.var;
885 return a.type < b.type;
888 /* Return true if constraint A is less than constraint B. This is just
889 arbitrary, but consistent, in order to give them an ordering. */
892 constraint_less (const constraint_t a, const constraint_t b)
894 if (constraint_expr_less (a->lhs, b->lhs))
896 else if (constraint_expr_less (b->lhs, a->lhs))
899 return constraint_expr_less (a->rhs, b->rhs);
902 /* Return true if two constraints A and B are equal. */
905 constraint_equal (struct constraint a, struct constraint b)
907 return constraint_expr_equal (a.lhs, b.lhs)
908 && constraint_expr_equal (a.rhs, b.rhs);
912 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
915 constraint_vec_find (VEC(constraint_t,heap) *vec,
916 struct constraint lookfor)
924 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
925 if (place >= VEC_length (constraint_t, vec))
927 found = VEC_index (constraint_t, vec, place);
928 if (!constraint_equal (*found, lookfor))
933 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
936 constraint_set_union (VEC(constraint_t,heap) **to,
937 VEC(constraint_t,heap) **from)
942 for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++)
944 if (constraint_vec_find (*to, *c) == NULL)
946 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
948 VEC_safe_insert (constraint_t, heap, *to, place, c);
953 /* Expands the solution in SET to all sub-fields of variables included.
954 Union the expanded result into RESULT. */
957 solution_set_expand (bitmap result, bitmap set)
963 /* In a first pass record all variables we need to add all
964 sub-fields off. This avoids quadratic behavior. */
965 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
967 varinfo_t v = get_varinfo (j);
968 if (v->is_artificial_var
971 v = lookup_vi_for_tree (v->decl);
973 vars = BITMAP_ALLOC (NULL);
974 bitmap_set_bit (vars, v->id);
977 /* In the second pass now do the addition to the solution and
978 to speed up solving add it to the delta as well. */
981 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
983 varinfo_t v = get_varinfo (j);
984 for (; v != NULL; v = v->next)
985 bitmap_set_bit (result, v->id);
991 /* Take a solution set SET, add OFFSET to each member of the set, and
992 overwrite SET with the result when done. */
995 solution_set_add (bitmap set, HOST_WIDE_INT offset)
997 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1001 /* If the offset is unknown we have to expand the solution to
1003 if (offset == UNKNOWN_OFFSET)
1005 solution_set_expand (set, set);
1009 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1011 varinfo_t vi = get_varinfo (i);
1013 /* If this is a variable with just one field just set its bit
1015 if (vi->is_artificial_var
1016 || vi->is_unknown_size_var
1018 bitmap_set_bit (result, i);
1021 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1023 /* If the offset makes the pointer point to before the
1024 variable use offset zero for the field lookup. */
1026 && fieldoffset > vi->offset)
1030 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1032 bitmap_set_bit (result, vi->id);
1033 /* If the result is not exactly at fieldoffset include the next
1034 field as well. See get_constraint_for_ptr_offset for more
1036 if (vi->offset != fieldoffset
1037 && vi->next != NULL)
1038 bitmap_set_bit (result, vi->next->id);
1042 bitmap_copy (set, result);
1043 BITMAP_FREE (result);
1046 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1050 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1053 return bitmap_ior_into (to, from);
1059 tmp = BITMAP_ALLOC (&iteration_obstack);
1060 bitmap_copy (tmp, from);
1061 solution_set_add (tmp, inc);
1062 res = bitmap_ior_into (to, tmp);
1068 /* Insert constraint C into the list of complex constraints for graph
1072 insert_into_complex (constraint_graph_t graph,
1073 unsigned int var, constraint_t c)
1075 VEC (constraint_t, heap) *complex = graph->complex[var];
1076 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1079 /* Only insert constraints that do not already exist. */
1080 if (place >= VEC_length (constraint_t, complex)
1081 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1082 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1086 /* Condense two variable nodes into a single variable node, by moving
1087 all associated info from SRC to TO. */
1090 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1096 gcc_assert (find (from) == to);
1098 /* Move all complex constraints from src node into to node */
1099 for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
1101 /* In complex constraints for node src, we may have either
1102 a = *src, and *src = a, or an offseted constraint which are
1103 always added to the rhs node's constraints. */
1105 if (c->rhs.type == DEREF)
1107 else if (c->lhs.type == DEREF)
1112 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1113 VEC_free (constraint_t, heap, graph->complex[from]);
1114 graph->complex[from] = NULL;
1118 /* Remove edges involving NODE from GRAPH. */
1121 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1123 if (graph->succs[node])
1124 BITMAP_FREE (graph->succs[node]);
1127 /* Merge GRAPH nodes FROM and TO into node TO. */
1130 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1133 if (graph->indirect_cycles[from] != -1)
1135 /* If we have indirect cycles with the from node, and we have
1136 none on the to node, the to node has indirect cycles from the
1137 from node now that they are unified.
1138 If indirect cycles exist on both, unify the nodes that they
1139 are in a cycle with, since we know they are in a cycle with
1141 if (graph->indirect_cycles[to] == -1)
1142 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1145 /* Merge all the successor edges. */
1146 if (graph->succs[from])
1148 if (!graph->succs[to])
1149 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1150 bitmap_ior_into (graph->succs[to],
1151 graph->succs[from]);
1154 clear_edges_for_node (graph, from);
1158 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1159 it doesn't exist in the graph already. */
1162 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1168 if (!graph->implicit_preds[to])
1169 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1171 if (bitmap_set_bit (graph->implicit_preds[to], from))
1172 stats.num_implicit_edges++;
1175 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1176 it doesn't exist in the graph already.
1177 Return false if the edge already existed, true otherwise. */
1180 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1183 if (!graph->preds[to])
1184 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1185 bitmap_set_bit (graph->preds[to], from);
1188 /* Add a graph edge to GRAPH, going from FROM to TO if
1189 it doesn't exist in the graph already.
1190 Return false if the edge already existed, true otherwise. */
1193 add_graph_edge (constraint_graph_t graph, unsigned int to,
1204 if (!graph->succs[from])
1205 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1206 if (bitmap_set_bit (graph->succs[from], to))
1209 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1217 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1220 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1223 return (graph->succs[dest]
1224 && bitmap_bit_p (graph->succs[dest], src));
1227 /* Initialize the constraint graph structure to contain SIZE nodes. */
1230 init_graph (unsigned int size)
1234 graph = XCNEW (struct constraint_graph);
1236 graph->succs = XCNEWVEC (bitmap, graph->size);
1237 graph->indirect_cycles = XNEWVEC (int, graph->size);
1238 graph->rep = XNEWVEC (unsigned int, graph->size);
1239 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1240 graph->pe = XCNEWVEC (unsigned int, graph->size);
1241 graph->pe_rep = XNEWVEC (int, graph->size);
1243 for (j = 0; j < graph->size; j++)
1246 graph->pe_rep[j] = -1;
1247 graph->indirect_cycles[j] = -1;
1251 /* Build the constraint graph, adding only predecessor edges right now. */
1254 build_pred_graph (void)
1260 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1261 graph->preds = XCNEWVEC (bitmap, graph->size);
1262 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1263 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1264 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1265 graph->points_to = XCNEWVEC (bitmap, graph->size);
1266 graph->eq_rep = XNEWVEC (int, graph->size);
1267 graph->direct_nodes = sbitmap_alloc (graph->size);
1268 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1269 sbitmap_zero (graph->direct_nodes);
1271 for (j = 0; j < FIRST_REF_NODE; j++)
1273 if (!get_varinfo (j)->is_special_var)
1274 SET_BIT (graph->direct_nodes, j);
1277 for (j = 0; j < graph->size; j++)
1278 graph->eq_rep[j] = -1;
1280 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1281 graph->indirect_cycles[j] = -1;
1283 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1285 struct constraint_expr lhs = c->lhs;
1286 struct constraint_expr rhs = c->rhs;
1287 unsigned int lhsvar = lhs.var;
1288 unsigned int rhsvar = rhs.var;
1290 if (lhs.type == DEREF)
1293 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1294 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1296 else if (rhs.type == DEREF)
1299 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1300 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1302 RESET_BIT (graph->direct_nodes, lhsvar);
1304 else if (rhs.type == ADDRESSOF)
1309 if (graph->points_to[lhsvar] == NULL)
1310 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1311 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1313 if (graph->pointed_by[rhsvar] == NULL)
1314 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1315 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1317 /* Implicitly, *x = y */
1318 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1320 /* All related variables are no longer direct nodes. */
1321 RESET_BIT (graph->direct_nodes, rhsvar);
1322 v = get_varinfo (rhsvar);
1323 if (!v->is_full_var)
1325 v = lookup_vi_for_tree (v->decl);
1328 RESET_BIT (graph->direct_nodes, v->id);
1333 bitmap_set_bit (graph->address_taken, rhsvar);
1335 else if (lhsvar > anything_id
1336 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1339 add_pred_graph_edge (graph, lhsvar, rhsvar);
1340 /* Implicitly, *x = *y */
1341 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1342 FIRST_REF_NODE + rhsvar);
1344 else if (lhs.offset != 0 || rhs.offset != 0)
1346 if (rhs.offset != 0)
1347 RESET_BIT (graph->direct_nodes, lhs.var);
1348 else if (lhs.offset != 0)
1349 RESET_BIT (graph->direct_nodes, rhs.var);
1354 /* Build the constraint graph, adding successor edges. */
1357 build_succ_graph (void)
1362 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1364 struct constraint_expr lhs;
1365 struct constraint_expr rhs;
1366 unsigned int lhsvar;
1367 unsigned int rhsvar;
1374 lhsvar = find (lhs.var);
1375 rhsvar = find (rhs.var);
1377 if (lhs.type == DEREF)
1379 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1380 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1382 else if (rhs.type == DEREF)
1384 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1385 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1387 else if (rhs.type == ADDRESSOF)
1390 gcc_assert (find (rhs.var) == rhs.var);
1391 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1393 else if (lhsvar > anything_id
1394 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1396 add_graph_edge (graph, lhsvar, rhsvar);
1400 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1401 receive pointers. */
1402 t = find (storedanything_id);
1403 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1405 if (!TEST_BIT (graph->direct_nodes, i)
1406 && get_varinfo (i)->may_have_pointers)
1407 add_graph_edge (graph, find (i), t);
1410 /* Everything stored to ANYTHING also potentially escapes. */
1411 add_graph_edge (graph, find (escaped_id), t);
1415 /* Changed variables on the last iteration. */
1416 static unsigned int changed_count;
1417 static sbitmap changed;
1419 /* Strongly Connected Component visitation info. */
1426 unsigned int *node_mapping;
1428 VEC(unsigned,heap) *scc_stack;
1432 /* Recursive routine to find strongly connected components in GRAPH.
1433 SI is the SCC info to store the information in, and N is the id of current
1434 graph node we are processing.
1436 This is Tarjan's strongly connected component finding algorithm, as
1437 modified by Nuutila to keep only non-root nodes on the stack.
1438 The algorithm can be found in "On finding the strongly connected
1439 connected components in a directed graph" by Esko Nuutila and Eljas
1440 Soisalon-Soininen, in Information Processing Letters volume 49,
1441 number 1, pages 9-14. */
1444 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1448 unsigned int my_dfs;
1450 SET_BIT (si->visited, n);
1451 si->dfs[n] = si->current_index ++;
1452 my_dfs = si->dfs[n];
1454 /* Visit all the successors. */
1455 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1459 if (i > LAST_REF_NODE)
1463 if (TEST_BIT (si->deleted, w))
1466 if (!TEST_BIT (si->visited, w))
1467 scc_visit (graph, si, w);
1469 unsigned int t = find (w);
1470 unsigned int nnode = find (n);
1471 gcc_assert (nnode == n);
1473 if (si->dfs[t] < si->dfs[nnode])
1474 si->dfs[n] = si->dfs[t];
1478 /* See if any components have been identified. */
1479 if (si->dfs[n] == my_dfs)
1481 if (VEC_length (unsigned, si->scc_stack) > 0
1482 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1484 bitmap scc = BITMAP_ALLOC (NULL);
1485 unsigned int lowest_node;
1488 bitmap_set_bit (scc, n);
1490 while (VEC_length (unsigned, si->scc_stack) != 0
1491 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1493 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1495 bitmap_set_bit (scc, w);
1498 lowest_node = bitmap_first_set_bit (scc);
1499 gcc_assert (lowest_node < FIRST_REF_NODE);
1501 /* Collapse the SCC nodes into a single node, and mark the
1503 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1505 if (i < FIRST_REF_NODE)
1507 if (unite (lowest_node, i))
1508 unify_nodes (graph, lowest_node, i, false);
1512 unite (lowest_node, i);
1513 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1517 SET_BIT (si->deleted, n);
1520 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1523 /* Unify node FROM into node TO, updating the changed count if
1524 necessary when UPDATE_CHANGED is true. */
1527 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1528 bool update_changed)
1531 gcc_assert (to != from && find (to) == to);
1532 if (dump_file && (dump_flags & TDF_DETAILS))
1533 fprintf (dump_file, "Unifying %s to %s\n",
1534 get_varinfo (from)->name,
1535 get_varinfo (to)->name);
1538 stats.unified_vars_dynamic++;
1540 stats.unified_vars_static++;
1542 merge_graph_nodes (graph, to, from);
1543 merge_node_constraints (graph, to, from);
1545 /* Mark TO as changed if FROM was changed. If TO was already marked
1546 as changed, decrease the changed count. */
1548 if (update_changed && TEST_BIT (changed, from))
1550 RESET_BIT (changed, from);
1551 if (!TEST_BIT (changed, to))
1552 SET_BIT (changed, to);
1555 gcc_assert (changed_count > 0);
1559 if (get_varinfo (from)->solution)
1561 /* If the solution changes because of the merging, we need to mark
1562 the variable as changed. */
1563 if (bitmap_ior_into (get_varinfo (to)->solution,
1564 get_varinfo (from)->solution))
1566 if (update_changed && !TEST_BIT (changed, to))
1568 SET_BIT (changed, to);
1573 BITMAP_FREE (get_varinfo (from)->solution);
1574 BITMAP_FREE (get_varinfo (from)->oldsolution);
1576 if (stats.iterations > 0)
1578 BITMAP_FREE (get_varinfo (to)->oldsolution);
1579 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1582 if (valid_graph_edge (graph, to, to))
1584 if (graph->succs[to])
1585 bitmap_clear_bit (graph->succs[to], to);
1589 /* Information needed to compute the topological ordering of a graph. */
1593 /* sbitmap of visited nodes. */
1595 /* Array that stores the topological order of the graph, *in
1597 VEC(unsigned,heap) *topo_order;
1601 /* Initialize and return a topological info structure. */
1603 static struct topo_info *
1604 init_topo_info (void)
1606 size_t size = graph->size;
1607 struct topo_info *ti = XNEW (struct topo_info);
1608 ti->visited = sbitmap_alloc (size);
1609 sbitmap_zero (ti->visited);
1610 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1615 /* Free the topological sort info pointed to by TI. */
1618 free_topo_info (struct topo_info *ti)
1620 sbitmap_free (ti->visited);
1621 VEC_free (unsigned, heap, ti->topo_order);
1625 /* Visit the graph in topological order, and store the order in the
1626 topo_info structure. */
1629 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1635 SET_BIT (ti->visited, n);
1637 if (graph->succs[n])
1638 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1640 if (!TEST_BIT (ti->visited, j))
1641 topo_visit (graph, ti, j);
1644 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1647 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1648 starting solution for y. */
1651 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1654 unsigned int lhs = c->lhs.var;
1656 bitmap sol = get_varinfo (lhs)->solution;
1659 HOST_WIDE_INT roffset = c->rhs.offset;
1661 /* Our IL does not allow this. */
1662 gcc_assert (c->lhs.offset == 0);
1664 /* If the solution of Y contains anything it is good enough to transfer
1666 if (bitmap_bit_p (delta, anything_id))
1668 flag |= bitmap_set_bit (sol, anything_id);
1672 /* If we do not know at with offset the rhs is dereferenced compute
1673 the reachability set of DELTA, conservatively assuming it is
1674 dereferenced at all valid offsets. */
1675 if (roffset == UNKNOWN_OFFSET)
1677 solution_set_expand (delta, delta);
1678 /* No further offset processing is necessary. */
1682 /* For each variable j in delta (Sol(y)), add
1683 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1684 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1686 varinfo_t v = get_varinfo (j);
1687 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1691 fieldoffset = v->offset;
1692 else if (roffset != 0)
1693 v = first_vi_for_offset (v, fieldoffset);
1694 /* If the access is outside of the variable we can ignore it. */
1702 /* Adding edges from the special vars is pointless.
1703 They don't have sets that can change. */
1704 if (get_varinfo (t)->is_special_var)
1705 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1706 /* Merging the solution from ESCAPED needlessly increases
1707 the set. Use ESCAPED as representative instead. */
1708 else if (v->id == escaped_id)
1709 flag |= bitmap_set_bit (sol, escaped_id);
1710 else if (v->may_have_pointers
1711 && add_graph_edge (graph, lhs, t))
1712 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1714 /* If the variable is not exactly at the requested offset
1715 we have to include the next one. */
1716 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1721 fieldoffset = v->offset;
1727 /* If the LHS solution changed, mark the var as changed. */
1730 get_varinfo (lhs)->solution = sol;
1731 if (!TEST_BIT (changed, lhs))
1733 SET_BIT (changed, lhs);
1739 /* Process a constraint C that represents *(x + off) = y using DELTA
1740 as the starting solution for x. */
1743 do_ds_constraint (constraint_t c, bitmap delta)
1745 unsigned int rhs = c->rhs.var;
1746 bitmap sol = get_varinfo (rhs)->solution;
1749 HOST_WIDE_INT loff = c->lhs.offset;
1750 bool escaped_p = false;
1752 /* Our IL does not allow this. */
1753 gcc_assert (c->rhs.offset == 0);
1755 /* If the solution of y contains ANYTHING simply use the ANYTHING
1756 solution. This avoids needlessly increasing the points-to sets. */
1757 if (bitmap_bit_p (sol, anything_id))
1758 sol = get_varinfo (find (anything_id))->solution;
1760 /* If the solution for x contains ANYTHING we have to merge the
1761 solution of y into all pointer variables which we do via
1763 if (bitmap_bit_p (delta, anything_id))
1765 unsigned t = find (storedanything_id);
1766 if (add_graph_edge (graph, t, rhs))
1768 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1770 if (!TEST_BIT (changed, t))
1772 SET_BIT (changed, t);
1780 /* If we do not know at with offset the rhs is dereferenced compute
1781 the reachability set of DELTA, conservatively assuming it is
1782 dereferenced at all valid offsets. */
1783 if (loff == UNKNOWN_OFFSET)
1785 solution_set_expand (delta, delta);
1789 /* For each member j of delta (Sol(x)), add an edge from y to j and
1790 union Sol(y) into Sol(j) */
1791 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1793 varinfo_t v = get_varinfo (j);
1795 HOST_WIDE_INT fieldoffset = v->offset + loff;
1798 fieldoffset = v->offset;
1800 v = first_vi_for_offset (v, fieldoffset);
1801 /* If the access is outside of the variable we can ignore it. */
1807 if (v->may_have_pointers)
1809 /* If v is a global variable then this is an escape point. */
1810 if (v->is_global_var
1813 t = find (escaped_id);
1814 if (add_graph_edge (graph, t, rhs)
1815 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1816 && !TEST_BIT (changed, t))
1818 SET_BIT (changed, t);
1821 /* Enough to let rhs escape once. */
1825 if (v->is_special_var)
1829 if (add_graph_edge (graph, t, rhs)
1830 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1831 && !TEST_BIT (changed, t))
1833 SET_BIT (changed, t);
1838 /* If the variable is not exactly at the requested offset
1839 we have to include the next one. */
1840 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1845 fieldoffset = v->offset;
1851 /* Handle a non-simple (simple meaning requires no iteration),
1852 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1855 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1857 if (c->lhs.type == DEREF)
1859 if (c->rhs.type == ADDRESSOF)
1866 do_ds_constraint (c, delta);
1869 else if (c->rhs.type == DEREF)
1872 if (!(get_varinfo (c->lhs.var)->is_special_var))
1873 do_sd_constraint (graph, c, delta);
1881 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1882 solution = get_varinfo (c->rhs.var)->solution;
1883 tmp = get_varinfo (c->lhs.var)->solution;
1885 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1889 get_varinfo (c->lhs.var)->solution = tmp;
1890 if (!TEST_BIT (changed, c->lhs.var))
1892 SET_BIT (changed, c->lhs.var);
1899 /* Initialize and return a new SCC info structure. */
1901 static struct scc_info *
1902 init_scc_info (size_t size)
1904 struct scc_info *si = XNEW (struct scc_info);
1907 si->current_index = 0;
1908 si->visited = sbitmap_alloc (size);
1909 sbitmap_zero (si->visited);
1910 si->deleted = sbitmap_alloc (size);
1911 sbitmap_zero (si->deleted);
1912 si->node_mapping = XNEWVEC (unsigned int, size);
1913 si->dfs = XCNEWVEC (unsigned int, size);
1915 for (i = 0; i < size; i++)
1916 si->node_mapping[i] = i;
1918 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1922 /* Free an SCC info structure pointed to by SI */
1925 free_scc_info (struct scc_info *si)
1927 sbitmap_free (si->visited);
1928 sbitmap_free (si->deleted);
1929 free (si->node_mapping);
1931 VEC_free (unsigned, heap, si->scc_stack);
1936 /* Find indirect cycles in GRAPH that occur, using strongly connected
1937 components, and note them in the indirect cycles map.
1939 This technique comes from Ben Hardekopf and Calvin Lin,
1940 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1941 Lines of Code", submitted to PLDI 2007. */
1944 find_indirect_cycles (constraint_graph_t graph)
1947 unsigned int size = graph->size;
1948 struct scc_info *si = init_scc_info (size);
1950 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1951 if (!TEST_BIT (si->visited, i) && find (i) == i)
1952 scc_visit (graph, si, i);
1957 /* Compute a topological ordering for GRAPH, and store the result in the
1958 topo_info structure TI. */
1961 compute_topo_order (constraint_graph_t graph,
1962 struct topo_info *ti)
1965 unsigned int size = graph->size;
1967 for (i = 0; i != size; ++i)
1968 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1969 topo_visit (graph, ti, i);
1972 /* Structure used to for hash value numbering of pointer equivalence
1975 typedef struct equiv_class_label
1978 unsigned int equivalence_class;
1980 } *equiv_class_label_t;
1981 typedef const struct equiv_class_label *const_equiv_class_label_t;
1983 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1985 static htab_t pointer_equiv_class_table;
1987 /* A hashtable for mapping a bitmap of labels->location equivalence
1989 static htab_t location_equiv_class_table;
1991 /* Hash function for a equiv_class_label_t */
1994 equiv_class_label_hash (const void *p)
1996 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1997 return ecl->hashcode;
2000 /* Equality function for two equiv_class_label_t's. */
2003 equiv_class_label_eq (const void *p1, const void *p2)
2005 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2006 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2007 return (eql1->hashcode == eql2->hashcode
2008 && bitmap_equal_p (eql1->labels, eql2->labels));
2011 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2015 equiv_class_lookup (htab_t table, bitmap labels)
2018 struct equiv_class_label ecl;
2020 ecl.labels = labels;
2021 ecl.hashcode = bitmap_hash (labels);
2023 slot = htab_find_slot_with_hash (table, &ecl,
2024 ecl.hashcode, NO_INSERT);
2028 return ((equiv_class_label_t) *slot)->equivalence_class;
2032 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2036 equiv_class_add (htab_t table, unsigned int equivalence_class,
2040 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2042 ecl->labels = labels;
2043 ecl->equivalence_class = equivalence_class;
2044 ecl->hashcode = bitmap_hash (labels);
2046 slot = htab_find_slot_with_hash (table, ecl,
2047 ecl->hashcode, INSERT);
2048 gcc_assert (!*slot);
2049 *slot = (void *) ecl;
2052 /* Perform offline variable substitution.
2054 This is a worst case quadratic time way of identifying variables
2055 that must have equivalent points-to sets, including those caused by
2056 static cycles, and single entry subgraphs, in the constraint graph.
2058 The technique is described in "Exploiting Pointer and Location
2059 Equivalence to Optimize Pointer Analysis. In the 14th International
2060 Static Analysis Symposium (SAS), August 2007." It is known as the
2061 "HU" algorithm, and is equivalent to value numbering the collapsed
2062 constraint graph including evaluating unions.
2064 The general method of finding equivalence classes is as follows:
2065 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2066 Initialize all non-REF nodes to be direct nodes.
2067 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2069 For each constraint containing the dereference, we also do the same
2072 We then compute SCC's in the graph and unify nodes in the same SCC,
2075 For each non-collapsed node x:
2076 Visit all unvisited explicit incoming edges.
2077 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2079 Lookup the equivalence class for pts(x).
2080 If we found one, equivalence_class(x) = found class.
2081 Otherwise, equivalence_class(x) = new class, and new_class is
2082 added to the lookup table.
2084 All direct nodes with the same equivalence class can be replaced
2085 with a single representative node.
2086 All unlabeled nodes (label == 0) are not pointers and all edges
2087 involving them can be eliminated.
2088 We perform these optimizations during rewrite_constraints
2090 In addition to pointer equivalence class finding, we also perform
2091 location equivalence class finding. This is the set of variables
2092 that always appear together in points-to sets. We use this to
2093 compress the size of the points-to sets. */
2095 /* Current maximum pointer equivalence class id. */
2096 static int pointer_equiv_class;
2098 /* Current maximum location equivalence class id. */
2099 static int location_equiv_class;
2101 /* Recursive routine to find strongly connected components in GRAPH,
2102 and label it's nodes with DFS numbers. */
2105 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2109 unsigned int my_dfs;
2111 gcc_assert (si->node_mapping[n] == n);
2112 SET_BIT (si->visited, n);
2113 si->dfs[n] = si->current_index ++;
2114 my_dfs = si->dfs[n];
2116 /* Visit all the successors. */
2117 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2119 unsigned int w = si->node_mapping[i];
2121 if (TEST_BIT (si->deleted, w))
2124 if (!TEST_BIT (si->visited, w))
2125 condense_visit (graph, si, w);
2127 unsigned int t = si->node_mapping[w];
2128 unsigned int nnode = si->node_mapping[n];
2129 gcc_assert (nnode == n);
2131 if (si->dfs[t] < si->dfs[nnode])
2132 si->dfs[n] = si->dfs[t];
2136 /* Visit all the implicit predecessors. */
2137 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2139 unsigned int w = si->node_mapping[i];
2141 if (TEST_BIT (si->deleted, w))
2144 if (!TEST_BIT (si->visited, w))
2145 condense_visit (graph, si, w);
2147 unsigned int t = si->node_mapping[w];
2148 unsigned int nnode = si->node_mapping[n];
2149 gcc_assert (nnode == n);
2151 if (si->dfs[t] < si->dfs[nnode])
2152 si->dfs[n] = si->dfs[t];
2156 /* See if any components have been identified. */
2157 if (si->dfs[n] == my_dfs)
2159 while (VEC_length (unsigned, si->scc_stack) != 0
2160 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2162 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2163 si->node_mapping[w] = n;
2165 if (!TEST_BIT (graph->direct_nodes, w))
2166 RESET_BIT (graph->direct_nodes, n);
2168 /* Unify our nodes. */
2169 if (graph->preds[w])
2171 if (!graph->preds[n])
2172 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2173 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2175 if (graph->implicit_preds[w])
2177 if (!graph->implicit_preds[n])
2178 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2179 bitmap_ior_into (graph->implicit_preds[n],
2180 graph->implicit_preds[w]);
2182 if (graph->points_to[w])
2184 if (!graph->points_to[n])
2185 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2186 bitmap_ior_into (graph->points_to[n],
2187 graph->points_to[w]);
2190 SET_BIT (si->deleted, n);
2193 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2196 /* Label pointer equivalences. */
2199 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2203 SET_BIT (si->visited, n);
2205 if (!graph->points_to[n])
2206 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2208 /* Label and union our incoming edges's points to sets. */
2209 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2211 unsigned int w = si->node_mapping[i];
2212 if (!TEST_BIT (si->visited, w))
2213 label_visit (graph, si, w);
2215 /* Skip unused edges */
2216 if (w == n || graph->pointer_label[w] == 0)
2219 if (graph->points_to[w])
2220 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2222 /* Indirect nodes get fresh variables. */
2223 if (!TEST_BIT (graph->direct_nodes, n))
2224 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2226 if (!bitmap_empty_p (graph->points_to[n]))
2228 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2229 graph->points_to[n]);
2232 label = pointer_equiv_class++;
2233 equiv_class_add (pointer_equiv_class_table,
2234 label, graph->points_to[n]);
2236 graph->pointer_label[n] = label;
2240 /* Perform offline variable substitution, discovering equivalence
2241 classes, and eliminating non-pointer variables. */
2243 static struct scc_info *
2244 perform_var_substitution (constraint_graph_t graph)
2247 unsigned int size = graph->size;
2248 struct scc_info *si = init_scc_info (size);
2250 bitmap_obstack_initialize (&iteration_obstack);
2251 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2252 equiv_class_label_eq, free);
2253 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2254 equiv_class_label_eq, free);
2255 pointer_equiv_class = 1;
2256 location_equiv_class = 1;
2258 /* Condense the nodes, which means to find SCC's, count incoming
2259 predecessors, and unite nodes in SCC's. */
2260 for (i = 0; i < FIRST_REF_NODE; i++)
2261 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2262 condense_visit (graph, si, si->node_mapping[i]);
2264 sbitmap_zero (si->visited);
2265 /* Actually the label the nodes for pointer equivalences */
2266 for (i = 0; i < FIRST_REF_NODE; i++)
2267 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2268 label_visit (graph, si, si->node_mapping[i]);
2270 /* Calculate location equivalence labels. */
2271 for (i = 0; i < FIRST_REF_NODE; i++)
2278 if (!graph->pointed_by[i])
2280 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2282 /* Translate the pointed-by mapping for pointer equivalence
2284 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2286 bitmap_set_bit (pointed_by,
2287 graph->pointer_label[si->node_mapping[j]]);
2289 /* The original pointed_by is now dead. */
2290 BITMAP_FREE (graph->pointed_by[i]);
2292 /* Look up the location equivalence label if one exists, or make
2294 label = equiv_class_lookup (location_equiv_class_table,
2298 label = location_equiv_class++;
2299 equiv_class_add (location_equiv_class_table,
2304 if (dump_file && (dump_flags & TDF_DETAILS))
2305 fprintf (dump_file, "Found location equivalence for node %s\n",
2306 get_varinfo (i)->name);
2307 BITMAP_FREE (pointed_by);
2309 graph->loc_label[i] = label;
2313 if (dump_file && (dump_flags & TDF_DETAILS))
2314 for (i = 0; i < FIRST_REF_NODE; i++)
2316 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2318 "Equivalence classes for %s node id %d:%s are pointer: %d"
2320 direct_node ? "Direct node" : "Indirect node", i,
2321 get_varinfo (i)->name,
2322 graph->pointer_label[si->node_mapping[i]],
2323 graph->loc_label[si->node_mapping[i]]);
2326 /* Quickly eliminate our non-pointer variables. */
2328 for (i = 0; i < FIRST_REF_NODE; i++)
2330 unsigned int node = si->node_mapping[i];
2332 if (graph->pointer_label[node] == 0)
2334 if (dump_file && (dump_flags & TDF_DETAILS))
2336 "%s is a non-pointer variable, eliminating edges.\n",
2337 get_varinfo (node)->name);
2338 stats.nonpointer_vars++;
2339 clear_edges_for_node (graph, node);
2346 /* Free information that was only necessary for variable
2350 free_var_substitution_info (struct scc_info *si)
2353 free (graph->pointer_label);
2354 free (graph->loc_label);
2355 free (graph->pointed_by);
2356 free (graph->points_to);
2357 free (graph->eq_rep);
2358 sbitmap_free (graph->direct_nodes);
2359 htab_delete (pointer_equiv_class_table);
2360 htab_delete (location_equiv_class_table);
2361 bitmap_obstack_release (&iteration_obstack);
2364 /* Return an existing node that is equivalent to NODE, which has
2365 equivalence class LABEL, if one exists. Return NODE otherwise. */
2368 find_equivalent_node (constraint_graph_t graph,
2369 unsigned int node, unsigned int label)
2371 /* If the address version of this variable is unused, we can
2372 substitute it for anything else with the same label.
2373 Otherwise, we know the pointers are equivalent, but not the
2374 locations, and we can unite them later. */
2376 if (!bitmap_bit_p (graph->address_taken, node))
2378 gcc_assert (label < graph->size);
2380 if (graph->eq_rep[label] != -1)
2382 /* Unify the two variables since we know they are equivalent. */
2383 if (unite (graph->eq_rep[label], node))
2384 unify_nodes (graph, graph->eq_rep[label], node, false);
2385 return graph->eq_rep[label];
2389 graph->eq_rep[label] = node;
2390 graph->pe_rep[label] = node;
2395 gcc_assert (label < graph->size);
2396 graph->pe[node] = label;
2397 if (graph->pe_rep[label] == -1)
2398 graph->pe_rep[label] = node;
2404 /* Unite pointer equivalent but not location equivalent nodes in
2405 GRAPH. This may only be performed once variable substitution is
2409 unite_pointer_equivalences (constraint_graph_t graph)
2413 /* Go through the pointer equivalences and unite them to their
2414 representative, if they aren't already. */
2415 for (i = 0; i < FIRST_REF_NODE; i++)
2417 unsigned int label = graph->pe[i];
2420 int label_rep = graph->pe_rep[label];
2422 if (label_rep == -1)
2425 label_rep = find (label_rep);
2426 if (label_rep >= 0 && unite (label_rep, find (i)))
2427 unify_nodes (graph, label_rep, i, false);
2432 /* Move complex constraints to the GRAPH nodes they belong to. */
2435 move_complex_constraints (constraint_graph_t graph)
2440 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2444 struct constraint_expr lhs = c->lhs;
2445 struct constraint_expr rhs = c->rhs;
2447 if (lhs.type == DEREF)
2449 insert_into_complex (graph, lhs.var, c);
2451 else if (rhs.type == DEREF)
2453 if (!(get_varinfo (lhs.var)->is_special_var))
2454 insert_into_complex (graph, rhs.var, c);
2456 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2457 && (lhs.offset != 0 || rhs.offset != 0))
2459 insert_into_complex (graph, rhs.var, c);
2466 /* Optimize and rewrite complex constraints while performing
2467 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2468 result of perform_variable_substitution. */
2471 rewrite_constraints (constraint_graph_t graph,
2472 struct scc_info *si)
2478 for (j = 0; j < graph->size; j++)
2479 gcc_assert (find (j) == j);
2481 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2483 struct constraint_expr lhs = c->lhs;
2484 struct constraint_expr rhs = c->rhs;
2485 unsigned int lhsvar = find (lhs.var);
2486 unsigned int rhsvar = find (rhs.var);
2487 unsigned int lhsnode, rhsnode;
2488 unsigned int lhslabel, rhslabel;
2490 lhsnode = si->node_mapping[lhsvar];
2491 rhsnode = si->node_mapping[rhsvar];
2492 lhslabel = graph->pointer_label[lhsnode];
2493 rhslabel = graph->pointer_label[rhsnode];
2495 /* See if it is really a non-pointer variable, and if so, ignore
2499 if (dump_file && (dump_flags & TDF_DETAILS))
2502 fprintf (dump_file, "%s is a non-pointer variable,"
2503 "ignoring constraint:",
2504 get_varinfo (lhs.var)->name);
2505 dump_constraint (dump_file, c);
2507 VEC_replace (constraint_t, constraints, i, NULL);
2513 if (dump_file && (dump_flags & TDF_DETAILS))
2516 fprintf (dump_file, "%s is a non-pointer variable,"
2517 "ignoring constraint:",
2518 get_varinfo (rhs.var)->name);
2519 dump_constraint (dump_file, c);
2521 VEC_replace (constraint_t, constraints, i, NULL);
2525 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2526 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2527 c->lhs.var = lhsvar;
2528 c->rhs.var = rhsvar;
2533 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2534 part of an SCC, false otherwise. */
2537 eliminate_indirect_cycles (unsigned int node)
2539 if (graph->indirect_cycles[node] != -1
2540 && !bitmap_empty_p (get_varinfo (node)->solution))
2543 VEC(unsigned,heap) *queue = NULL;
2545 unsigned int to = find (graph->indirect_cycles[node]);
2548 /* We can't touch the solution set and call unify_nodes
2549 at the same time, because unify_nodes is going to do
2550 bitmap unions into it. */
2552 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2554 if (find (i) == i && i != to)
2557 VEC_safe_push (unsigned, heap, queue, i);
2562 VEC_iterate (unsigned, queue, queuepos, i);
2565 unify_nodes (graph, to, i, true);
2567 VEC_free (unsigned, heap, queue);
2573 /* Solve the constraint graph GRAPH using our worklist solver.
2574 This is based on the PW* family of solvers from the "Efficient Field
2575 Sensitive Pointer Analysis for C" paper.
2576 It works by iterating over all the graph nodes, processing the complex
2577 constraints and propagating the copy constraints, until everything stops
2578 changed. This corresponds to steps 6-8 in the solving list given above. */
2581 solve_graph (constraint_graph_t graph)
2583 unsigned int size = graph->size;
2588 changed = sbitmap_alloc (size);
2589 sbitmap_zero (changed);
2591 /* Mark all initial non-collapsed nodes as changed. */
2592 for (i = 0; i < size; i++)
2594 varinfo_t ivi = get_varinfo (i);
2595 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2596 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2597 || VEC_length (constraint_t, graph->complex[i]) > 0))
2599 SET_BIT (changed, i);
2604 /* Allocate a bitmap to be used to store the changed bits. */
2605 pts = BITMAP_ALLOC (&pta_obstack);
2607 while (changed_count > 0)
2610 struct topo_info *ti = init_topo_info ();
2613 bitmap_obstack_initialize (&iteration_obstack);
2615 compute_topo_order (graph, ti);
2617 while (VEC_length (unsigned, ti->topo_order) != 0)
2620 i = VEC_pop (unsigned, ti->topo_order);
2622 /* If this variable is not a representative, skip it. */
2626 /* In certain indirect cycle cases, we may merge this
2627 variable to another. */
2628 if (eliminate_indirect_cycles (i) && find (i) != i)
2631 /* If the node has changed, we need to process the
2632 complex constraints and outgoing edges again. */
2633 if (TEST_BIT (changed, i))
2638 VEC(constraint_t,heap) *complex = graph->complex[i];
2639 bool solution_empty;
2641 RESET_BIT (changed, i);
2644 /* Compute the changed set of solution bits. */
2645 bitmap_and_compl (pts, get_varinfo (i)->solution,
2646 get_varinfo (i)->oldsolution);
2648 if (bitmap_empty_p (pts))
2651 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2653 solution = get_varinfo (i)->solution;
2654 solution_empty = bitmap_empty_p (solution);
2656 /* Process the complex constraints */
2657 for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++)
2659 /* XXX: This is going to unsort the constraints in
2660 some cases, which will occasionally add duplicate
2661 constraints during unification. This does not
2662 affect correctness. */
2663 c->lhs.var = find (c->lhs.var);
2664 c->rhs.var = find (c->rhs.var);
2666 /* The only complex constraint that can change our
2667 solution to non-empty, given an empty solution,
2668 is a constraint where the lhs side is receiving
2669 some set from elsewhere. */
2670 if (!solution_empty || c->lhs.type != DEREF)
2671 do_complex_constraint (graph, c, pts);
2674 solution_empty = bitmap_empty_p (solution);
2676 if (!solution_empty)
2679 unsigned eff_escaped_id = find (escaped_id);
2681 /* Propagate solution to all successors. */
2682 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2688 unsigned int to = find (j);
2689 tmp = get_varinfo (to)->solution;
2692 /* Don't try to propagate to ourselves. */
2696 /* If we propagate from ESCAPED use ESCAPED as
2698 if (i == eff_escaped_id)
2699 flag = bitmap_set_bit (tmp, escaped_id);
2701 flag = set_union_with_increment (tmp, pts, 0);
2705 get_varinfo (to)->solution = tmp;
2706 if (!TEST_BIT (changed, to))
2708 SET_BIT (changed, to);
2716 free_topo_info (ti);
2717 bitmap_obstack_release (&iteration_obstack);
2721 sbitmap_free (changed);
2722 bitmap_obstack_release (&oldpta_obstack);
2725 /* Map from trees to variable infos. */
2726 static struct pointer_map_t *vi_for_tree;
2729 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2732 insert_vi_for_tree (tree t, varinfo_t vi)
2734 void **slot = pointer_map_insert (vi_for_tree, t);
2736 gcc_assert (*slot == NULL);
2740 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2741 exist in the map, return NULL, otherwise, return the varinfo we found. */
2744 lookup_vi_for_tree (tree t)
2746 void **slot = pointer_map_contains (vi_for_tree, t);
2750 return (varinfo_t) *slot;
2753 /* Return a printable name for DECL */
2756 alias_get_name (tree decl)
2760 int num_printed = 0;
2762 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2763 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2765 res= get_name (decl);
2773 if (TREE_CODE (decl) == SSA_NAME)
2775 num_printed = asprintf (&temp, "%s_%u",
2776 alias_get_name (SSA_NAME_VAR (decl)),
2777 SSA_NAME_VERSION (decl));
2779 else if (DECL_P (decl))
2781 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2783 if (num_printed > 0)
2785 res = ggc_strdup (temp);
2791 /* Find the variable id for tree T in the map.
2792 If T doesn't exist in the map, create an entry for it and return it. */
2795 get_vi_for_tree (tree t)
2797 void **slot = pointer_map_contains (vi_for_tree, t);
2799 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2801 return (varinfo_t) *slot;
2804 /* Get a scalar constraint expression for a new temporary variable. */
2806 static struct constraint_expr
2807 new_scalar_tmp_constraint_exp (const char *name)
2809 struct constraint_expr tmp;
2812 vi = new_var_info (NULL_TREE, name);
2816 vi->is_full_var = 1;
2825 /* Get a constraint expression vector from an SSA_VAR_P node.
2826 If address_p is true, the result will be taken its address of. */
2829 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2831 struct constraint_expr cexpr;
2834 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2835 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2837 /* For parameters, get at the points-to set for the actual parm
2839 if (TREE_CODE (t) == SSA_NAME
2840 && TREE_CODE (SSA_NAME_VAR (t)) == PARM_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 forzero = TREE_OPERAND (forzero, 0);
3114 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3116 struct constraint_expr temp;
3119 temp.var = integer_id;
3121 VEC_safe_push (ce_s, heap, *results, &temp);
3125 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3127 /* Pretend to take the address of the base, we'll take care of
3128 adding the required subset of sub-fields below. */
3129 get_constraint_for_1 (t, results, true);
3130 gcc_assert (VEC_length (ce_s, *results) == 1);
3131 result = VEC_last (ce_s, *results);
3133 if (result->type == SCALAR
3134 && get_varinfo (result->var)->is_full_var)
3135 /* For single-field vars do not bother about the offset. */
3137 else if (result->type == SCALAR)
3139 /* In languages like C, you can access one past the end of an
3140 array. You aren't allowed to dereference it, so we can
3141 ignore this constraint. When we handle pointer subtraction,
3142 we may have to do something cute here. */
3144 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3147 /* It's also not true that the constraint will actually start at the
3148 right offset, it may start in some padding. We only care about
3149 setting the constraint to the first actual field it touches, so
3151 struct constraint_expr cexpr = *result;
3153 VEC_pop (ce_s, *results);
3155 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3157 if (ranges_overlap_p (curr->offset, curr->size,
3158 bitpos, bitmaxsize))
3160 cexpr.var = curr->id;
3161 VEC_safe_push (ce_s, heap, *results, &cexpr);
3166 /* If we are going to take the address of this field then
3167 to be able to compute reachability correctly add at least
3168 the last field of the variable. */
3170 && VEC_length (ce_s, *results) == 0)
3172 curr = get_varinfo (cexpr.var);
3173 while (curr->next != NULL)
3175 cexpr.var = curr->id;
3176 VEC_safe_push (ce_s, heap, *results, &cexpr);
3179 /* Assert that we found *some* field there. The user couldn't be
3180 accessing *only* padding. */
3181 /* Still the user could access one past the end of an array
3182 embedded in a struct resulting in accessing *only* padding. */
3183 gcc_assert (VEC_length (ce_s, *results) >= 1
3184 || ref_contains_array_ref (orig_t));
3186 else if (bitmaxsize == 0)
3188 if (dump_file && (dump_flags & TDF_DETAILS))
3189 fprintf (dump_file, "Access to zero-sized part of variable,"
3193 if (dump_file && (dump_flags & TDF_DETAILS))
3194 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3196 else if (result->type == DEREF)
3198 /* If we do not know exactly where the access goes say so. Note
3199 that only for non-structure accesses we know that we access
3200 at most one subfiled of any variable. */
3202 || bitsize != bitmaxsize
3203 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3204 result->offset = UNKNOWN_OFFSET;
3206 result->offset = bitpos;
3208 else if (result->type == ADDRESSOF)
3210 /* We can end up here for component references on a
3211 VIEW_CONVERT_EXPR <>(&foobar). */
3212 result->type = SCALAR;
3213 result->var = anything_id;
3221 /* Dereference the constraint expression CONS, and return the result.
3222 DEREF (ADDRESSOF) = SCALAR
3223 DEREF (SCALAR) = DEREF
3224 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3225 This is needed so that we can handle dereferencing DEREF constraints. */
3228 do_deref (VEC (ce_s, heap) **constraints)
3230 struct constraint_expr *c;
3233 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3235 if (c->type == SCALAR)
3237 else if (c->type == ADDRESSOF)
3239 else if (c->type == DEREF)
3241 struct constraint_expr tmplhs;
3242 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3243 process_constraint (new_constraint (tmplhs, *c));
3244 c->var = tmplhs.var;
3251 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3253 /* Given a tree T, return the constraint expression for taking the
3257 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3259 struct constraint_expr *c;
3262 get_constraint_for_1 (t, results, true);
3264 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3266 if (c->type == DEREF)
3269 c->type = ADDRESSOF;
3273 /* Given a tree T, return the constraint expression for it. */
3276 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3278 struct constraint_expr temp;
3280 /* x = integer is all glommed to a single variable, which doesn't
3281 point to anything by itself. That is, of course, unless it is an
3282 integer constant being treated as a pointer, in which case, we
3283 will return that this is really the addressof anything. This
3284 happens below, since it will fall into the default case. The only
3285 case we know something about an integer treated like a pointer is
3286 when it is the NULL pointer, and then we just say it points to
3289 Do not do that if -fno-delete-null-pointer-checks though, because
3290 in that case *NULL does not fail, so it _should_ alias *anything.
3291 It is not worth adding a new option or renaming the existing one,
3292 since this case is relatively obscure. */
3293 if ((TREE_CODE (t) == INTEGER_CST
3294 && integer_zerop (t))
3295 /* The only valid CONSTRUCTORs in gimple with pointer typed
3296 elements are zero-initializer. But in IPA mode we also
3297 process global initializers, so verify at least. */
3298 || (TREE_CODE (t) == CONSTRUCTOR
3299 && CONSTRUCTOR_NELTS (t) == 0))
3301 if (flag_delete_null_pointer_checks)
3302 temp.var = nothing_id;
3304 temp.var = anything_id;
3305 temp.type = ADDRESSOF;
3307 VEC_safe_push (ce_s, heap, *results, &temp);
3311 /* String constants are read-only. */
3312 if (TREE_CODE (t) == STRING_CST)
3314 temp.var = readonly_id;
3317 VEC_safe_push (ce_s, heap, *results, &temp);
3321 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3323 case tcc_expression:
3325 switch (TREE_CODE (t))
3328 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3336 switch (TREE_CODE (t))
3340 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3345 case ARRAY_RANGE_REF:
3347 get_constraint_for_component_ref (t, results, address_p);
3349 case VIEW_CONVERT_EXPR:
3350 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3352 /* We are missing handling for TARGET_MEM_REF here. */
3357 case tcc_exceptional:
3359 switch (TREE_CODE (t))
3363 get_constraint_for_ssa_var (t, results, address_p);
3370 VEC (ce_s, heap) *tmp = NULL;
3371 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3373 struct constraint_expr *rhsp;
3375 get_constraint_for_1 (val, &tmp, address_p);
3376 for (j = 0; VEC_iterate (ce_s, tmp, j, rhsp); ++j)
3377 VEC_safe_push (ce_s, heap, *results, rhsp);
3378 VEC_truncate (ce_s, tmp, 0);
3380 VEC_free (ce_s, heap, tmp);
3381 /* We do not know whether the constructor was complete,
3382 so technically we have to add &NOTHING or &ANYTHING
3383 like we do for an empty constructor as well. */
3390 case tcc_declaration:
3392 get_constraint_for_ssa_var (t, results, address_p);
3398 /* The default fallback is a constraint from anything. */
3399 temp.type = ADDRESSOF;
3400 temp.var = anything_id;
3402 VEC_safe_push (ce_s, heap, *results, &temp);
3405 /* Given a gimple tree T, return the constraint expression vector for it. */
3408 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3410 gcc_assert (VEC_length (ce_s, *results) == 0);
3412 get_constraint_for_1 (t, results, false);
3416 /* Efficiently generates constraints from all entries in *RHSC to all
3417 entries in *LHSC. */
3420 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3422 struct constraint_expr *lhsp, *rhsp;
3425 if (VEC_length (ce_s, lhsc) <= 1
3426 || VEC_length (ce_s, rhsc) <= 1)
3428 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3429 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3430 process_constraint (new_constraint (*lhsp, *rhsp));
3434 struct constraint_expr tmp;
3435 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3436 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3437 process_constraint (new_constraint (tmp, *rhsp));
3438 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3439 process_constraint (new_constraint (*lhsp, tmp));
3443 /* Handle aggregate copies by expanding into copies of the respective
3444 fields of the structures. */
3447 do_structure_copy (tree lhsop, tree rhsop)
3449 struct constraint_expr *lhsp, *rhsp;
3450 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3453 get_constraint_for (lhsop, &lhsc);
3454 get_constraint_for (rhsop, &rhsc);
3455 lhsp = VEC_index (ce_s, lhsc, 0);
3456 rhsp = VEC_index (ce_s, rhsc, 0);
3457 if (lhsp->type == DEREF
3458 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3459 || rhsp->type == DEREF)
3461 if (lhsp->type == DEREF)
3463 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3464 lhsp->offset = UNKNOWN_OFFSET;
3466 if (rhsp->type == DEREF)
3468 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3469 rhsp->offset = UNKNOWN_OFFSET;
3471 process_all_all_constraints (lhsc, rhsc);
3473 else if (lhsp->type == SCALAR
3474 && (rhsp->type == SCALAR
3475 || rhsp->type == ADDRESSOF))
3477 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3478 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3480 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3481 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3482 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3484 varinfo_t lhsv, rhsv;
3485 rhsp = VEC_index (ce_s, rhsc, k);
3486 lhsv = get_varinfo (lhsp->var);
3487 rhsv = get_varinfo (rhsp->var);
3488 if (lhsv->may_have_pointers
3489 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3490 rhsv->offset + lhsoffset, rhsv->size))
3491 process_constraint (new_constraint (*lhsp, *rhsp));
3492 if (lhsv->offset + rhsoffset + lhsv->size
3493 > rhsv->offset + lhsoffset + rhsv->size)
3496 if (k >= VEC_length (ce_s, rhsc))
3506 VEC_free (ce_s, heap, lhsc);
3507 VEC_free (ce_s, heap, rhsc);
3510 /* Create a constraint ID = OP. */
3513 make_constraint_to (unsigned id, tree op)
3515 VEC(ce_s, heap) *rhsc = NULL;
3516 struct constraint_expr *c;
3517 struct constraint_expr includes;
3521 includes.offset = 0;
3522 includes.type = SCALAR;
3524 get_constraint_for (op, &rhsc);
3525 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3526 process_constraint (new_constraint (includes, *c));
3527 VEC_free (ce_s, heap, rhsc);
3530 /* Create a constraint ID = &FROM. */
3533 make_constraint_from (varinfo_t vi, int from)
3535 struct constraint_expr lhs, rhs;
3543 rhs.type = ADDRESSOF;
3544 process_constraint (new_constraint (lhs, rhs));
3547 /* Create a constraint ID = FROM. */
3550 make_copy_constraint (varinfo_t vi, int from)
3552 struct constraint_expr lhs, rhs;
3561 process_constraint (new_constraint (lhs, rhs));
3564 /* Make constraints necessary to make OP escape. */
3567 make_escape_constraint (tree op)
3569 make_constraint_to (escaped_id, op);
3572 /* Add constraints to that the solution of VI is transitively closed. */
3575 make_transitive_closure_constraints (varinfo_t vi)
3577 struct constraint_expr lhs, rhs;
3586 process_constraint (new_constraint (lhs, rhs));
3588 /* VAR = VAR + UNKNOWN; */
3594 rhs.offset = UNKNOWN_OFFSET;
3595 process_constraint (new_constraint (lhs, rhs));
3598 /* Create a new artificial heap variable with NAME.
3599 Return the created variable. */
3602 make_heapvar_for (varinfo_t lhs, const char *name)
3605 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3607 if (heapvar == NULL_TREE)
3610 heapvar = create_tmp_var_raw (ptr_type_node, name);
3611 DECL_EXTERNAL (heapvar) = 1;
3613 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3615 ann = get_var_ann (heapvar);
3616 ann->is_heapvar = 1;
3619 /* For global vars we need to add a heapvar to the list of referenced
3620 vars of a different function than it was created for originally. */
3621 if (cfun && gimple_referenced_vars (cfun))
3622 add_referenced_var (heapvar);
3624 vi = new_var_info (heapvar, name);
3625 vi->is_artificial_var = true;
3626 vi->is_heap_var = true;
3627 vi->is_unknown_size_var = true;
3631 vi->is_full_var = true;
3632 insert_vi_for_tree (heapvar, vi);
3637 /* Create a new artificial heap variable with NAME and make a
3638 constraint from it to LHS. Return the created variable. */
3641 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3643 varinfo_t vi = make_heapvar_for (lhs, name);
3644 make_constraint_from (lhs, vi->id);
3649 /* Create a new artificial heap variable with NAME and make a
3650 constraint from it to LHS. Set flags according to a tag used
3651 for tracking restrict pointers. */
3654 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3657 vi = make_constraint_from_heapvar (lhs, name);
3658 vi->is_restrict_var = 1;
3659 vi->is_global_var = 0;
3660 vi->is_special_var = 1;
3661 vi->may_have_pointers = 0;
3664 /* In IPA mode there are varinfos for different aspects of reach
3665 function designator. One for the points-to set of the return
3666 value, one for the variables that are clobbered by the function,
3667 one for its uses and one for each parameter (including a single
3668 glob for remaining variadic arguments). */
3670 enum { fi_clobbers = 1, fi_uses = 2,
3671 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3673 /* Get a constraint for the requested part of a function designator FI
3674 when operating in IPA mode. */
3676 static struct constraint_expr
3677 get_function_part_constraint (varinfo_t fi, unsigned part)
3679 struct constraint_expr c;
3681 gcc_assert (in_ipa_mode);
3683 if (fi->id == anything_id)
3685 /* ??? We probably should have a ANYFN special variable. */
3686 c.var = anything_id;
3690 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3692 varinfo_t ai = first_vi_for_offset (fi, part);
3696 c.var = anything_id;
3710 /* For non-IPA mode, generate constraints necessary for a call on the
3714 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3716 struct constraint_expr rhsc;
3718 bool returns_uses = false;
3720 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3722 tree arg = gimple_call_arg (stmt, i);
3723 int flags = gimple_call_arg_flags (stmt, i);
3725 /* If the argument is not used or it does not contain pointers
3726 we can ignore it. */
3727 if ((flags & EAF_UNUSED)
3728 || !could_have_pointers (arg))
3731 /* As we compute ESCAPED context-insensitive we do not gain
3732 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3733 set. The argument would still get clobbered through the
3735 ??? We might get away with less (and more precise) constraints
3736 if using a temporary for transitively closing things. */
3737 if ((flags & EAF_NOCLOBBER)
3738 && (flags & EAF_NOESCAPE))
3740 varinfo_t uses = get_call_use_vi (stmt);
3741 if (!(flags & EAF_DIRECT))
3742 make_transitive_closure_constraints (uses);
3743 make_constraint_to (uses->id, arg);
3744 returns_uses = true;
3746 else if (flags & EAF_NOESCAPE)
3748 varinfo_t uses = get_call_use_vi (stmt);
3749 varinfo_t clobbers = get_call_clobber_vi (stmt);
3750 if (!(flags & EAF_DIRECT))
3752 make_transitive_closure_constraints (uses);
3753 make_transitive_closure_constraints (clobbers);
3755 make_constraint_to (uses->id, arg);
3756 make_constraint_to (clobbers->id, arg);
3757 returns_uses = true;
3760 make_escape_constraint (arg);
3763 /* If we added to the calls uses solution make sure we account for
3764 pointers to it to be returned. */
3767 rhsc.var = get_call_use_vi (stmt)->id;
3770 VEC_safe_push (ce_s, heap, *results, &rhsc);
3773 /* The static chain escapes as well. */
3774 if (gimple_call_chain (stmt))
3775 make_escape_constraint (gimple_call_chain (stmt));
3777 /* And if we applied NRV the address of the return slot escapes as well. */
3778 if (gimple_call_return_slot_opt_p (stmt)
3779 && gimple_call_lhs (stmt) != NULL_TREE
3780 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3782 VEC(ce_s, heap) *tmpc = NULL;
3783 struct constraint_expr lhsc, *c;
3784 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3785 lhsc.var = escaped_id;
3788 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3789 process_constraint (new_constraint (lhsc, *c));
3790 VEC_free(ce_s, heap, tmpc);
3793 /* Regular functions return nonlocal memory. */
3794 rhsc.var = nonlocal_id;
3797 VEC_safe_push (ce_s, heap, *results, &rhsc);
3800 /* For non-IPA mode, generate constraints necessary for a call
3801 that returns a pointer and assigns it to LHS. This simply makes
3802 the LHS point to global and escaped variables. */
3805 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3808 VEC(ce_s, heap) *lhsc = NULL;
3810 get_constraint_for (lhs, &lhsc);
3811 /* If the store is to a global decl make sure to
3812 add proper escape constraints. */
3813 lhs = get_base_address (lhs);
3816 && is_global_var (lhs))
3818 struct constraint_expr tmpc;
3819 tmpc.var = escaped_id;
3822 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3825 /* If the call returns an argument unmodified override the rhs
3827 flags = gimple_call_return_flags (stmt);
3828 if (flags & ERF_RETURNS_ARG
3829 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3833 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3834 get_constraint_for (arg, &rhsc);
3835 process_all_all_constraints (lhsc, rhsc);
3836 VEC_free (ce_s, heap, rhsc);
3838 else if (flags & ERF_NOALIAS)
3841 struct constraint_expr tmpc;
3843 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3844 /* We delay marking allocated storage global until we know if
3846 DECL_EXTERNAL (vi->decl) = 0;
3847 vi->is_global_var = 0;
3848 /* If this is not a real malloc call assume the memory was
3849 initialized and thus may point to global memory. All
3850 builtin functions with the malloc attribute behave in a sane way. */
3852 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3853 make_constraint_from (vi, nonlocal_id);
3856 tmpc.type = ADDRESSOF;
3857 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3860 process_all_all_constraints (lhsc, rhsc);
3862 VEC_free (ce_s, heap, lhsc);
3865 /* For non-IPA mode, generate constraints necessary for a call of a
3866 const function that returns a pointer in the statement STMT. */
3869 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3871 struct constraint_expr rhsc;
3874 /* Treat nested const functions the same as pure functions as far
3875 as the static chain is concerned. */
3876 if (gimple_call_chain (stmt))
3878 varinfo_t uses = get_call_use_vi (stmt);
3879 make_transitive_closure_constraints (uses);
3880 make_constraint_to (uses->id, gimple_call_chain (stmt));
3881 rhsc.var = uses->id;
3884 VEC_safe_push (ce_s, heap, *results, &rhsc);
3887 /* May return arguments. */
3888 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3890 tree arg = gimple_call_arg (stmt, k);
3892 if (could_have_pointers (arg))
3894 VEC(ce_s, heap) *argc = NULL;
3896 struct constraint_expr *argp;
3897 get_constraint_for (arg, &argc);
3898 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3899 VEC_safe_push (ce_s, heap, *results, argp);
3900 VEC_free(ce_s, heap, argc);
3904 /* May return addresses of globals. */
3905 rhsc.var = nonlocal_id;
3907 rhsc.type = ADDRESSOF;
3908 VEC_safe_push (ce_s, heap, *results, &rhsc);
3911 /* For non-IPA mode, generate constraints necessary for a call to a
3912 pure function in statement STMT. */
3915 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3917 struct constraint_expr rhsc;
3919 varinfo_t uses = NULL;
3921 /* Memory reached from pointer arguments is call-used. */
3922 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3924 tree arg = gimple_call_arg (stmt, i);
3926 if (could_have_pointers (arg))
3930 uses = get_call_use_vi (stmt);
3931 make_transitive_closure_constraints (uses);
3933 make_constraint_to (uses->id, arg);
3937 /* The static chain is used as well. */
3938 if (gimple_call_chain (stmt))
3942 uses = get_call_use_vi (stmt);
3943 make_transitive_closure_constraints (uses);
3945 make_constraint_to (uses->id, gimple_call_chain (stmt));
3948 /* Pure functions may return call-used and nonlocal memory. */
3951 rhsc.var = uses->id;
3954 VEC_safe_push (ce_s, heap, *results, &rhsc);
3956 rhsc.var = nonlocal_id;
3959 VEC_safe_push (ce_s, heap, *results, &rhsc);
3963 /* Return the varinfo for the callee of CALL. */
3966 get_fi_for_callee (gimple call)
3970 /* If we can directly resolve the function being called, do so.
3971 Otherwise, it must be some sort of indirect expression that
3972 we should still be able to handle. */
3973 decl = gimple_call_fndecl (call);
3975 return get_vi_for_tree (decl);
3977 decl = gimple_call_fn (call);
3978 /* The function can be either an SSA name pointer or,
3979 worse, an OBJ_TYPE_REF. In this case we have no
3980 clue and should be getting ANYFN (well, ANYTHING for now). */
3981 if (TREE_CODE (decl) == SSA_NAME)
3983 if (TREE_CODE (decl) == SSA_NAME
3984 && TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3985 && SSA_NAME_IS_DEFAULT_DEF (decl))
3986 decl = SSA_NAME_VAR (decl);
3987 return get_vi_for_tree (decl);
3989 else if (TREE_CODE (decl) == INTEGER_CST
3990 || TREE_CODE (decl) == OBJ_TYPE_REF)
3991 return get_varinfo (anything_id);
3996 /* Walk statement T setting up aliasing constraints according to the
3997 references found in T. This function is the main part of the
3998 constraint builder. AI points to auxiliary alias information used
3999 when building alias sets and computing alias grouping heuristics. */
4002 find_func_aliases (gimple origt)
4005 VEC(ce_s, heap) *lhsc = NULL;
4006 VEC(ce_s, heap) *rhsc = NULL;
4007 struct constraint_expr *c;
4010 /* Now build constraints expressions. */
4011 if (gimple_code (t) == GIMPLE_PHI)
4013 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4015 /* Only care about pointers and structures containing
4017 if (could_have_pointers (gimple_phi_result (t)))
4022 /* For a phi node, assign all the arguments to
4024 get_constraint_for (gimple_phi_result (t), &lhsc);
4025 for (i = 0; i < gimple_phi_num_args (t); i++)
4027 tree strippedrhs = PHI_ARG_DEF (t, i);
4029 STRIP_NOPS (strippedrhs);
4030 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
4032 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
4034 struct constraint_expr *c2;
4035 while (VEC_length (ce_s, rhsc) > 0)
4037 c2 = VEC_last (ce_s, rhsc);
4038 process_constraint (new_constraint (*c, *c2));
4039 VEC_pop (ce_s, rhsc);
4045 /* In IPA mode, we need to generate constraints to pass call
4046 arguments through their calls. There are two cases,
4047 either a GIMPLE_CALL returning a value, or just a plain
4048 GIMPLE_CALL when we are not.
4050 In non-ipa mode, we need to generate constraints for each
4051 pointer passed by address. */
4052 else if (is_gimple_call (t))
4054 tree fndecl = gimple_call_fndecl (t);
4055 if (fndecl != NULL_TREE
4056 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4057 /* ??? All builtins that are handled here need to be handled
4058 in the alias-oracle query functions explicitly! */
4059 switch (DECL_FUNCTION_CODE (fndecl))
4061 /* All the following functions return a pointer to the same object
4062 as their first argument points to. The functions do not add
4063 to the ESCAPED solution. The functions make the first argument
4064 pointed to memory point to what the second argument pointed to
4065 memory points to. */
4066 case BUILT_IN_STRCPY:
4067 case BUILT_IN_STRNCPY:
4068 case BUILT_IN_BCOPY:
4069 case BUILT_IN_MEMCPY:
4070 case BUILT_IN_MEMMOVE:
4071 case BUILT_IN_MEMPCPY:
4072 case BUILT_IN_STPCPY:
4073 case BUILT_IN_STPNCPY:
4074 case BUILT_IN_STRCAT:
4075 case BUILT_IN_STRNCAT:
4077 tree res = gimple_call_lhs (t);
4078 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4079 == BUILT_IN_BCOPY ? 1 : 0));
4080 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4081 == BUILT_IN_BCOPY ? 0 : 1));
4082 if (res != NULL_TREE)
4084 get_constraint_for (res, &lhsc);
4085 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4086 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4087 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4088 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4090 get_constraint_for (dest, &rhsc);
4091 process_all_all_constraints (lhsc, rhsc);
4092 VEC_free (ce_s, heap, lhsc);
4093 VEC_free (ce_s, heap, rhsc);
4095 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4096 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4099 process_all_all_constraints (lhsc, rhsc);
4100 VEC_free (ce_s, heap, lhsc);
4101 VEC_free (ce_s, heap, rhsc);
4104 case BUILT_IN_MEMSET:
4106 tree res = gimple_call_lhs (t);
4107 tree dest = gimple_call_arg (t, 0);
4110 struct constraint_expr ac;
4111 if (res != NULL_TREE)
4113 get_constraint_for (res, &lhsc);
4114 get_constraint_for (dest, &rhsc);
4115 process_all_all_constraints (lhsc, rhsc);
4116 VEC_free (ce_s, heap, lhsc);
4117 VEC_free (ce_s, heap, rhsc);
4119 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4121 if (flag_delete_null_pointer_checks
4122 && integer_zerop (gimple_call_arg (t, 1)))
4124 ac.type = ADDRESSOF;
4125 ac.var = nothing_id;
4130 ac.var = integer_id;
4133 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4134 process_constraint (new_constraint (*lhsp, ac));
4135 VEC_free (ce_s, heap, lhsc);
4138 /* All the following functions do not return pointers, do not
4139 modify the points-to sets of memory reachable from their
4140 arguments and do not add to the ESCAPED solution. */
4141 case BUILT_IN_SINCOS:
4142 case BUILT_IN_SINCOSF:
4143 case BUILT_IN_SINCOSL:
4144 case BUILT_IN_FREXP:
4145 case BUILT_IN_FREXPF:
4146 case BUILT_IN_FREXPL:
4147 case BUILT_IN_GAMMA_R:
4148 case BUILT_IN_GAMMAF_R:
4149 case BUILT_IN_GAMMAL_R:
4150 case BUILT_IN_LGAMMA_R:
4151 case BUILT_IN_LGAMMAF_R:
4152 case BUILT_IN_LGAMMAL_R:
4154 case BUILT_IN_MODFF:
4155 case BUILT_IN_MODFL:
4156 case BUILT_IN_REMQUO:
4157 case BUILT_IN_REMQUOF:
4158 case BUILT_IN_REMQUOL:
4161 /* Trampolines are special - they set up passing the static
4163 case BUILT_IN_INIT_TRAMPOLINE:
4165 tree tramp = gimple_call_arg (t, 0);
4166 tree nfunc = gimple_call_arg (t, 1);
4167 tree frame = gimple_call_arg (t, 2);
4169 struct constraint_expr lhs, *rhsp;
4172 varinfo_t nfi = NULL;
4173 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4174 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4177 lhs = get_function_part_constraint (nfi, fi_static_chain);
4178 get_constraint_for (frame, &rhsc);
4179 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
4180 process_constraint (new_constraint (lhs, *rhsp));
4181 VEC_free (ce_s, heap, rhsc);
4183 /* Make the frame point to the function for
4184 the trampoline adjustment call. */
4185 get_constraint_for (tramp, &lhsc);
4187 get_constraint_for (nfunc, &rhsc);
4188 process_all_all_constraints (lhsc, rhsc);
4189 VEC_free (ce_s, heap, rhsc);
4190 VEC_free (ce_s, heap, lhsc);
4195 /* Else fallthru to generic handling which will let
4196 the frame escape. */
4199 case BUILT_IN_ADJUST_TRAMPOLINE:
4201 tree tramp = gimple_call_arg (t, 0);
4202 tree res = gimple_call_lhs (t);
4203 if (in_ipa_mode && res)
4205 get_constraint_for (res, &lhsc);
4206 get_constraint_for (tramp, &rhsc);
4208 process_all_all_constraints (lhsc, rhsc);
4209 VEC_free (ce_s, heap, rhsc);
4210 VEC_free (ce_s, heap, lhsc);
4214 /* Variadic argument handling needs to be handled in IPA
4216 case BUILT_IN_VA_START:
4220 tree valist = gimple_call_arg (t, 0);
4221 struct constraint_expr rhs, *lhsp;
4223 /* The va_list gets access to pointers in variadic
4225 fi = lookup_vi_for_tree (cfun->decl);
4226 gcc_assert (fi != NULL);
4227 get_constraint_for (valist, &lhsc);
4229 rhs = get_function_part_constraint (fi, ~0);
4230 rhs.type = ADDRESSOF;
4231 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4232 process_constraint (new_constraint (*lhsp, rhs));
4233 VEC_free (ce_s, heap, lhsc);
4234 /* va_list is clobbered. */
4235 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4240 /* va_end doesn't have any effect that matters. */
4241 case BUILT_IN_VA_END:
4243 /* Alternate return. Simply give up for now. */
4244 case BUILT_IN_RETURN:
4248 || !(fi = get_vi_for_tree (cfun->decl)))
4249 make_constraint_from (get_varinfo (escaped_id), anything_id);
4250 else if (in_ipa_mode
4253 struct constraint_expr lhs, rhs;
4254 lhs = get_function_part_constraint (fi, fi_result);
4255 rhs.var = anything_id;
4258 process_constraint (new_constraint (lhs, rhs));
4262 /* printf-style functions may have hooks to set pointers to
4263 point to somewhere into the generated string. Leave them
4264 for a later excercise... */
4266 /* Fallthru to general call handling. */;
4270 && (!(fi = lookup_vi_for_tree (fndecl))
4271 || !fi->is_fn_info)))
4273 VEC(ce_s, heap) *rhsc = NULL;
4274 int flags = gimple_call_flags (t);
4276 /* Const functions can return their arguments and addresses
4277 of global memory but not of escaped memory. */
4278 if (flags & (ECF_CONST|ECF_NOVOPS))
4280 if (gimple_call_lhs (t)
4281 && could_have_pointers (gimple_call_lhs (t)))
4282 handle_const_call (t, &rhsc);
4284 /* Pure functions can return addresses in and of memory
4285 reachable from their arguments, but they are not an escape
4286 point for reachable memory of their arguments. */
4287 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4288 handle_pure_call (t, &rhsc);
4290 handle_rhs_call (t, &rhsc);
4291 if (gimple_call_lhs (t)
4292 && could_have_pointers (gimple_call_lhs (t)))
4293 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4294 VEC_free (ce_s, heap, rhsc);
4301 fi = get_fi_for_callee (t);
4303 /* Assign all the passed arguments to the appropriate incoming
4304 parameters of the function. */
4305 for (j = 0; j < gimple_call_num_args (t); j++)
4307 struct constraint_expr lhs ;
4308 struct constraint_expr *rhsp;
4309 tree arg = gimple_call_arg (t, j);
4311 if (!could_have_pointers (arg))
4314 get_constraint_for (arg, &rhsc);
4315 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4316 while (VEC_length (ce_s, rhsc) != 0)
4318 rhsp = VEC_last (ce_s, rhsc);
4319 process_constraint (new_constraint (lhs, *rhsp));
4320 VEC_pop (ce_s, rhsc);
4324 /* If we are returning a value, assign it to the result. */
4325 lhsop = gimple_call_lhs (t);
4327 && type_could_have_pointers (TREE_TYPE (lhsop)))
4329 struct constraint_expr rhs;
4330 struct constraint_expr *lhsp;
4332 get_constraint_for (lhsop, &lhsc);
4333 rhs = get_function_part_constraint (fi, fi_result);
4335 && DECL_RESULT (fndecl)
4336 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4338 VEC(ce_s, heap) *tem = NULL;
4339 VEC_safe_push (ce_s, heap, tem, &rhs);
4341 rhs = *VEC_index (ce_s, tem, 0);
4342 VEC_free(ce_s, heap, tem);
4344 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4345 process_constraint (new_constraint (*lhsp, rhs));
4348 /* If we pass the result decl by reference, honor that. */
4351 && DECL_RESULT (fndecl)
4352 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4354 struct constraint_expr lhs;
4355 struct constraint_expr *rhsp;
4357 get_constraint_for_address_of (lhsop, &rhsc);
4358 lhs = get_function_part_constraint (fi, fi_result);
4359 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4360 process_constraint (new_constraint (lhs, *rhsp));
4361 VEC_free (ce_s, heap, rhsc);
4364 /* If we use a static chain, pass it along. */
4365 if (gimple_call_chain (t))
4367 struct constraint_expr lhs;
4368 struct constraint_expr *rhsp;
4370 get_constraint_for (gimple_call_chain (t), &rhsc);
4371 lhs = get_function_part_constraint (fi, fi_static_chain);
4372 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4373 process_constraint (new_constraint (lhs, *rhsp));
4377 /* Otherwise, just a regular assignment statement. Only care about
4378 operations with pointer result, others are dealt with as escape
4379 points if they have pointer operands. */
4380 else if (is_gimple_assign (t)
4381 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4383 /* Otherwise, just a regular assignment statement. */
4384 tree lhsop = gimple_assign_lhs (t);
4385 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4387 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4388 do_structure_copy (lhsop, rhsop);
4391 struct constraint_expr temp;
4392 get_constraint_for (lhsop, &lhsc);
4394 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4395 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4396 gimple_assign_rhs2 (t), &rhsc);
4397 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4398 && !(POINTER_TYPE_P (gimple_expr_type (t))
4399 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4400 || gimple_assign_single_p (t))
4401 get_constraint_for (rhsop, &rhsc);
4404 temp.type = ADDRESSOF;
4405 temp.var = anything_id;
4407 VEC_safe_push (ce_s, heap, rhsc, &temp);
4409 process_all_all_constraints (lhsc, rhsc);
4411 /* If there is a store to a global variable the rhs escapes. */
4412 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4414 && is_global_var (lhsop)
4416 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4417 make_escape_constraint (rhsop);
4418 /* If this is a conversion of a non-restrict pointer to a
4419 restrict pointer track it with a new heapvar. */
4420 else if (gimple_assign_cast_p (t)
4421 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4422 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4423 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4424 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4425 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4428 /* For conversions of pointers to non-pointers the pointer escapes. */
4429 else if (gimple_assign_cast_p (t)
4430 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4431 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4433 make_escape_constraint (gimple_assign_rhs1 (t));
4435 /* Handle escapes through return. */
4436 else if (gimple_code (t) == GIMPLE_RETURN
4437 && gimple_return_retval (t) != NULL_TREE
4438 && could_have_pointers (gimple_return_retval (t)))
4442 || !(fi = get_vi_for_tree (cfun->decl)))
4443 make_escape_constraint (gimple_return_retval (t));
4444 else if (in_ipa_mode
4447 struct constraint_expr lhs ;
4448 struct constraint_expr *rhsp;
4451 lhs = get_function_part_constraint (fi, fi_result);
4452 get_constraint_for (gimple_return_retval (t), &rhsc);
4453 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4454 process_constraint (new_constraint (lhs, *rhsp));
4457 /* Handle asms conservatively by adding escape constraints to everything. */
4458 else if (gimple_code (t) == GIMPLE_ASM)
4460 unsigned i, noutputs;
4461 const char **oconstraints;
4462 const char *constraint;
4463 bool allows_mem, allows_reg, is_inout;
4465 noutputs = gimple_asm_noutputs (t);
4466 oconstraints = XALLOCAVEC (const char *, noutputs);
4468 for (i = 0; i < noutputs; ++i)
4470 tree link = gimple_asm_output_op (t, i);
4471 tree op = TREE_VALUE (link);
4473 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4474 oconstraints[i] = constraint;
4475 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4476 &allows_reg, &is_inout);
4478 /* A memory constraint makes the address of the operand escape. */
4479 if (!allows_reg && allows_mem)
4480 make_escape_constraint (build_fold_addr_expr (op));
4482 /* The asm may read global memory, so outputs may point to
4483 any global memory. */
4484 if (op && could_have_pointers (op))
4486 VEC(ce_s, heap) *lhsc = NULL;
4487 struct constraint_expr rhsc, *lhsp;
4489 get_constraint_for (op, &lhsc);
4490 rhsc.var = nonlocal_id;
4493 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4494 process_constraint (new_constraint (*lhsp, rhsc));
4495 VEC_free (ce_s, heap, lhsc);
4498 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4500 tree link = gimple_asm_input_op (t, i);
4501 tree op = TREE_VALUE (link);
4503 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4505 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4506 &allows_mem, &allows_reg);
4508 /* A memory constraint makes the address of the operand escape. */
4509 if (!allows_reg && allows_mem)
4510 make_escape_constraint (build_fold_addr_expr (op));
4511 /* Strictly we'd only need the constraint to ESCAPED if
4512 the asm clobbers memory, otherwise using something
4513 along the lines of per-call clobbers/uses would be enough. */
4514 else if (op && could_have_pointers (op))
4515 make_escape_constraint (op);
4519 VEC_free (ce_s, heap, rhsc);
4520 VEC_free (ce_s, heap, lhsc);
4524 /* Create a constraint adding to the clobber set of FI the memory
4525 pointed to by PTR. */
4528 process_ipa_clobber (varinfo_t fi, tree ptr)
4530 VEC(ce_s, heap) *ptrc = NULL;
4531 struct constraint_expr *c, lhs;
4533 get_constraint_for (ptr, &ptrc);
4534 lhs = get_function_part_constraint (fi, fi_clobbers);
4535 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4536 process_constraint (new_constraint (lhs, *c));
4537 VEC_free (ce_s, heap, ptrc);
4540 /* Walk statement T setting up clobber and use constraints according to the
4541 references found in T. This function is a main part of the
4542 IPA constraint builder. */
4545 find_func_clobbers (gimple origt)
4548 VEC(ce_s, heap) *lhsc = NULL;
4549 VEC(ce_s, heap) *rhsc = NULL;
4552 /* Add constraints for clobbered/used in IPA mode.
4553 We are not interested in what automatic variables are clobbered
4554 or used as we only use the information in the caller to which
4555 they do not escape. */
4556 gcc_assert (in_ipa_mode);
4558 /* If the stmt refers to memory in any way it better had a VUSE. */
4559 if (gimple_vuse (t) == NULL_TREE)
4562 /* We'd better have function information for the current function. */
4563 fi = lookup_vi_for_tree (cfun->decl);
4564 gcc_assert (fi != NULL);
4566 /* Account for stores in assignments and calls. */
4567 if (gimple_vdef (t) != NULL_TREE
4568 && gimple_has_lhs (t))
4570 tree lhs = gimple_get_lhs (t);
4572 while (handled_component_p (tem))
4573 tem = TREE_OPERAND (tem, 0);
4575 && !auto_var_in_fn_p (tem, cfun->decl))
4576 || INDIRECT_REF_P (tem))
4578 struct constraint_expr lhsc, *rhsp;
4580 lhsc = get_function_part_constraint (fi, fi_clobbers);
4581 get_constraint_for_address_of (lhs, &rhsc);
4582 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4583 process_constraint (new_constraint (lhsc, *rhsp));
4584 VEC_free (ce_s, heap, rhsc);
4588 /* Account for uses in assigments and returns. */
4589 if (gimple_assign_single_p (t)
4590 || (gimple_code (t) == GIMPLE_RETURN
4591 && gimple_return_retval (t) != NULL_TREE))
4593 tree rhs = (gimple_assign_single_p (t)
4594 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4596 while (handled_component_p (tem))
4597 tem = TREE_OPERAND (tem, 0);
4599 && !auto_var_in_fn_p (tem, cfun->decl))
4600 || INDIRECT_REF_P (tem))
4602 struct constraint_expr lhs, *rhsp;
4604 lhs = get_function_part_constraint (fi, fi_uses);
4605 get_constraint_for_address_of (rhs, &rhsc);
4606 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4607 process_constraint (new_constraint (lhs, *rhsp));
4608 VEC_free (ce_s, heap, rhsc);
4612 if (is_gimple_call (t))
4614 varinfo_t cfi = NULL;
4615 tree decl = gimple_call_fndecl (t);
4616 struct constraint_expr lhs, rhs;
4619 /* For builtins we do not have separate function info. For those
4620 we do not generate escapes for we have to generate clobbers/uses. */
4622 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4623 switch (DECL_FUNCTION_CODE (decl))
4625 /* The following functions use and clobber memory pointed to
4626 by their arguments. */
4627 case BUILT_IN_STRCPY:
4628 case BUILT_IN_STRNCPY:
4629 case BUILT_IN_BCOPY:
4630 case BUILT_IN_MEMCPY:
4631 case BUILT_IN_MEMMOVE:
4632 case BUILT_IN_MEMPCPY:
4633 case BUILT_IN_STPCPY:
4634 case BUILT_IN_STPNCPY:
4635 case BUILT_IN_STRCAT:
4636 case BUILT_IN_STRNCAT:
4638 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4639 == BUILT_IN_BCOPY ? 1 : 0));
4640 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4641 == BUILT_IN_BCOPY ? 0 : 1));
4643 struct constraint_expr *rhsp, *lhsp;
4644 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4645 lhs = get_function_part_constraint (fi, fi_clobbers);
4646 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4647 process_constraint (new_constraint (lhs, *lhsp));
4648 VEC_free (ce_s, heap, lhsc);
4649 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4650 lhs = get_function_part_constraint (fi, fi_uses);
4651 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4652 process_constraint (new_constraint (lhs, *rhsp));
4653 VEC_free (ce_s, heap, rhsc);
4656 /* The following function clobbers memory pointed to by
4658 case BUILT_IN_MEMSET:
4660 tree dest = gimple_call_arg (t, 0);
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);
4670 /* The following functions clobber their second and third
4672 case BUILT_IN_SINCOS:
4673 case BUILT_IN_SINCOSF:
4674 case BUILT_IN_SINCOSL:
4676 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4677 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4680 /* The following functions clobber their second argument. */
4681 case BUILT_IN_FREXP:
4682 case BUILT_IN_FREXPF:
4683 case BUILT_IN_FREXPL:
4684 case BUILT_IN_LGAMMA_R:
4685 case BUILT_IN_LGAMMAF_R:
4686 case BUILT_IN_LGAMMAL_R:
4687 case BUILT_IN_GAMMA_R:
4688 case BUILT_IN_GAMMAF_R:
4689 case BUILT_IN_GAMMAL_R:
4691 case BUILT_IN_MODFF:
4692 case BUILT_IN_MODFL:
4694 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4697 /* The following functions clobber their third argument. */
4698 case BUILT_IN_REMQUO:
4699 case BUILT_IN_REMQUOF:
4700 case BUILT_IN_REMQUOL:
4702 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4705 /* The following functions neither read nor clobber memory. */
4708 /* Trampolines are of no interest to us. */
4709 case BUILT_IN_INIT_TRAMPOLINE:
4710 case BUILT_IN_ADJUST_TRAMPOLINE:
4712 case BUILT_IN_VA_START:
4713 case BUILT_IN_VA_END:
4715 /* printf-style functions may have hooks to set pointers to
4716 point to somewhere into the generated string. Leave them
4717 for a later excercise... */
4719 /* Fallthru to general call handling. */;
4722 /* Parameters passed by value are used. */
4723 lhs = get_function_part_constraint (fi, fi_uses);
4724 for (i = 0; i < gimple_call_num_args (t); i++)
4726 struct constraint_expr *rhsp;
4727 tree arg = gimple_call_arg (t, i);
4729 if (TREE_CODE (arg) == SSA_NAME
4730 || is_gimple_min_invariant (arg))
4733 get_constraint_for_address_of (arg, &rhsc);
4734 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4735 process_constraint (new_constraint (lhs, *rhsp));
4736 VEC_free (ce_s, heap, rhsc);
4739 /* Build constraints for propagating clobbers/uses along the
4741 cfi = get_fi_for_callee (t);
4742 if (cfi->id == anything_id)
4744 if (gimple_vdef (t))
4745 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4747 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4752 /* For callees without function info (that's external functions),
4753 ESCAPED is clobbered and used. */
4754 if (gimple_call_fndecl (t)
4755 && !cfi->is_fn_info)
4759 if (gimple_vdef (t))
4760 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4762 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4764 /* Also honor the call statement use/clobber info. */
4765 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4766 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4768 if ((vi = lookup_call_use_vi (t)) != NULL)
4769 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4774 /* Otherwise the caller clobbers and uses what the callee does.
4775 ??? This should use a new complex constraint that filters
4776 local variables of the callee. */
4777 if (gimple_vdef (t))
4779 lhs = get_function_part_constraint (fi, fi_clobbers);
4780 rhs = get_function_part_constraint (cfi, fi_clobbers);
4781 process_constraint (new_constraint (lhs, rhs));
4783 lhs = get_function_part_constraint (fi, fi_uses);
4784 rhs = get_function_part_constraint (cfi, fi_uses);
4785 process_constraint (new_constraint (lhs, rhs));
4787 else if (gimple_code (t) == GIMPLE_ASM)
4789 /* ??? Ick. We can do better. */
4790 if (gimple_vdef (t))
4791 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4793 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4797 VEC_free (ce_s, heap, rhsc);
4801 /* Find the first varinfo in the same variable as START that overlaps with
4802 OFFSET. Return NULL if we can't find one. */
4805 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4807 /* If the offset is outside of the variable, bail out. */
4808 if (offset >= start->fullsize)
4811 /* If we cannot reach offset from start, lookup the first field
4812 and start from there. */
4813 if (start->offset > offset)
4814 start = lookup_vi_for_tree (start->decl);
4818 /* We may not find a variable in the field list with the actual
4819 offset when when we have glommed a structure to a variable.
4820 In that case, however, offset should still be within the size
4822 if (offset >= start->offset
4823 && (offset - start->offset) < start->size)
4832 /* Find the first varinfo in the same variable as START that overlaps with
4833 OFFSET. If there is no such varinfo the varinfo directly preceding
4834 OFFSET is returned. */
4837 first_or_preceding_vi_for_offset (varinfo_t start,
4838 unsigned HOST_WIDE_INT offset)
4840 /* If we cannot reach offset from start, lookup the first field
4841 and start from there. */
4842 if (start->offset > offset)
4843 start = lookup_vi_for_tree (start->decl);
4845 /* We may not find a variable in the field list with the actual
4846 offset when when we have glommed a structure to a variable.
4847 In that case, however, offset should still be within the size
4849 If we got beyond the offset we look for return the field
4850 directly preceding offset which may be the last field. */
4852 && offset >= start->offset
4853 && !((offset - start->offset) < start->size))
4854 start = start->next;
4860 /* This structure is used during pushing fields onto the fieldstack
4861 to track the offset of the field, since bitpos_of_field gives it
4862 relative to its immediate containing type, and we want it relative
4863 to the ultimate containing object. */
4867 /* Offset from the base of the base containing object to this field. */
4868 HOST_WIDE_INT offset;
4870 /* Size, in bits, of the field. */
4871 unsigned HOST_WIDE_INT size;
4873 unsigned has_unknown_size : 1;
4875 unsigned may_have_pointers : 1;
4877 unsigned only_restrict_pointers : 1;
4879 typedef struct fieldoff fieldoff_s;
4881 DEF_VEC_O(fieldoff_s);
4882 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4884 /* qsort comparison function for two fieldoff's PA and PB */
4887 fieldoff_compare (const void *pa, const void *pb)
4889 const fieldoff_s *foa = (const fieldoff_s *)pa;
4890 const fieldoff_s *fob = (const fieldoff_s *)pb;
4891 unsigned HOST_WIDE_INT foasize, fobsize;
4893 if (foa->offset < fob->offset)
4895 else if (foa->offset > fob->offset)
4898 foasize = foa->size;
4899 fobsize = fob->size;
4900 if (foasize < fobsize)
4902 else if (foasize > fobsize)
4907 /* Sort a fieldstack according to the field offset and sizes. */
4909 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4911 qsort (VEC_address (fieldoff_s, fieldstack),
4912 VEC_length (fieldoff_s, fieldstack),
4913 sizeof (fieldoff_s),
4917 /* Return true if V is a tree that we can have subvars for.
4918 Normally, this is any aggregate type. Also complex
4919 types which are not gimple registers can have subvars. */
4922 var_can_have_subvars (const_tree v)
4924 /* Volatile variables should never have subvars. */
4925 if (TREE_THIS_VOLATILE (v))
4928 /* Non decls or memory tags can never have subvars. */
4932 /* Aggregates without overlapping fields can have subvars. */
4933 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4939 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4940 the fields of TYPE onto fieldstack, recording their offsets along
4943 OFFSET is used to keep track of the offset in this entire
4944 structure, rather than just the immediately containing structure.
4945 Returns false if the caller is supposed to handle the field we
4949 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4950 HOST_WIDE_INT offset, bool must_have_pointers_p)
4953 bool empty_p = true;
4955 if (TREE_CODE (type) != RECORD_TYPE)
4958 /* If the vector of fields is growing too big, bail out early.
4959 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4961 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4964 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4965 if (TREE_CODE (field) == FIELD_DECL)
4968 HOST_WIDE_INT foff = bitpos_of_field (field);
4970 if (!var_can_have_subvars (field)
4971 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4972 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4974 else if (!push_fields_onto_fieldstack
4975 (TREE_TYPE (field), fieldstack, offset + foff,
4976 must_have_pointers_p)
4977 && (DECL_SIZE (field)
4978 && !integer_zerop (DECL_SIZE (field))))
4979 /* Empty structures may have actual size, like in C++. So
4980 see if we didn't push any subfields and the size is
4981 nonzero, push the field onto the stack. */
4986 fieldoff_s *pair = NULL;
4987 bool has_unknown_size = false;
4989 if (!VEC_empty (fieldoff_s, *fieldstack))
4990 pair = VEC_last (fieldoff_s, *fieldstack);
4992 if (!DECL_SIZE (field)
4993 || !host_integerp (DECL_SIZE (field), 1))
4994 has_unknown_size = true;
4996 /* If adjacent fields do not contain pointers merge them. */
4998 && !pair->may_have_pointers
4999 && !pair->has_unknown_size
5000 && !has_unknown_size
5001 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
5002 && !must_have_pointers_p
5003 && !could_have_pointers (field))
5005 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5009 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5010 pair->offset = offset + foff;
5011 pair->has_unknown_size = has_unknown_size;
5012 if (!has_unknown_size)
5013 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5016 pair->may_have_pointers
5017 = must_have_pointers_p || could_have_pointers (field);
5018 pair->only_restrict_pointers
5019 = (!has_unknown_size
5020 && POINTER_TYPE_P (TREE_TYPE (field))
5021 && TYPE_RESTRICT (TREE_TYPE (field)));
5031 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5032 if it is a varargs function. */
5035 count_num_arguments (tree decl, bool *is_varargs)
5037 unsigned int num = 0;
5040 /* Capture named arguments for K&R functions. They do not
5041 have a prototype and thus no TYPE_ARG_TYPES. */
5042 for (t = DECL_ARGUMENTS (decl); t; t = TREE_CHAIN (t))
5045 /* Check if the function has variadic arguments. */
5046 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5047 if (TREE_VALUE (t) == void_type_node)
5055 /* Creation function node for DECL, using NAME, and return the index
5056 of the variable we've created for the function. */
5059 create_function_info_for (tree decl, const char *name)
5061 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5062 varinfo_t vi, prev_vi;
5065 bool is_varargs = false;
5066 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5068 /* Create the variable info. */
5070 vi = new_var_info (decl, name);
5073 vi->fullsize = fi_parm_base + num_args;
5075 vi->may_have_pointers = false;
5078 insert_vi_for_tree (vi->decl, vi);
5082 /* Create a variable for things the function clobbers and one for
5083 things the function uses. */
5085 varinfo_t clobbervi, usevi;
5086 const char *newname;
5089 asprintf (&tempname, "%s.clobber", name);
5090 newname = ggc_strdup (tempname);
5093 clobbervi = new_var_info (NULL, newname);
5094 clobbervi->offset = fi_clobbers;
5095 clobbervi->size = 1;
5096 clobbervi->fullsize = vi->fullsize;
5097 clobbervi->is_full_var = true;
5098 clobbervi->is_global_var = false;
5099 gcc_assert (prev_vi->offset < clobbervi->offset);
5100 prev_vi->next = clobbervi;
5101 prev_vi = clobbervi;
5103 asprintf (&tempname, "%s.use", name);
5104 newname = ggc_strdup (tempname);
5107 usevi = new_var_info (NULL, newname);
5108 usevi->offset = fi_uses;
5110 usevi->fullsize = vi->fullsize;
5111 usevi->is_full_var = true;
5112 usevi->is_global_var = false;
5113 gcc_assert (prev_vi->offset < usevi->offset);
5114 prev_vi->next = usevi;
5118 /* And one for the static chain. */
5119 if (fn->static_chain_decl != NULL_TREE)
5122 const char *newname;
5125 asprintf (&tempname, "%s.chain", name);
5126 newname = ggc_strdup (tempname);
5129 chainvi = new_var_info (fn->static_chain_decl, newname);
5130 chainvi->offset = fi_static_chain;
5132 chainvi->fullsize = vi->fullsize;
5133 chainvi->is_full_var = true;
5134 chainvi->is_global_var = false;
5135 gcc_assert (prev_vi->offset < chainvi->offset);
5136 prev_vi->next = chainvi;
5138 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5141 /* Create a variable for the return var. */
5142 if (DECL_RESULT (decl) != NULL
5143 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5146 const char *newname;
5148 tree resultdecl = decl;
5150 if (DECL_RESULT (decl))
5151 resultdecl = DECL_RESULT (decl);
5153 asprintf (&tempname, "%s.result", name);
5154 newname = ggc_strdup (tempname);
5157 resultvi = new_var_info (resultdecl, newname);
5158 resultvi->offset = fi_result;
5160 resultvi->fullsize = vi->fullsize;
5161 resultvi->is_full_var = true;
5162 if (DECL_RESULT (decl))
5163 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5164 gcc_assert (prev_vi->offset < resultvi->offset);
5165 prev_vi->next = resultvi;
5167 if (DECL_RESULT (decl))
5168 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5171 /* Set up variables for each argument. */
5172 arg = DECL_ARGUMENTS (decl);
5173 for (i = 0; i < num_args; i++)
5176 const char *newname;
5178 tree argdecl = decl;
5183 asprintf (&tempname, "%s.arg%d", name, i);
5184 newname = ggc_strdup (tempname);
5187 argvi = new_var_info (argdecl, newname);
5188 argvi->offset = fi_parm_base + i;
5190 argvi->is_full_var = true;
5191 argvi->fullsize = vi->fullsize;
5193 argvi->may_have_pointers = could_have_pointers (arg);
5194 gcc_assert (prev_vi->offset < argvi->offset);
5195 prev_vi->next = argvi;
5199 insert_vi_for_tree (arg, argvi);
5200 arg = TREE_CHAIN (arg);
5204 /* Add one representative for all further args. */
5208 const char *newname;
5212 asprintf (&tempname, "%s.varargs", name);
5213 newname = ggc_strdup (tempname);
5216 /* We need sth that can be pointed to for va_start. */
5217 decl = create_tmp_var_raw (ptr_type_node, name);
5220 argvi = new_var_info (decl, newname);
5221 argvi->offset = fi_parm_base + num_args;
5223 argvi->is_full_var = true;
5224 argvi->is_heap_var = true;
5225 argvi->fullsize = vi->fullsize;
5226 gcc_assert (prev_vi->offset < argvi->offset);
5227 prev_vi->next = argvi;
5235 /* Return true if FIELDSTACK contains fields that overlap.
5236 FIELDSTACK is assumed to be sorted by offset. */
5239 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5241 fieldoff_s *fo = NULL;
5243 HOST_WIDE_INT lastoffset = -1;
5245 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5247 if (fo->offset == lastoffset)
5249 lastoffset = fo->offset;
5254 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5255 This will also create any varinfo structures necessary for fields
5259 create_variable_info_for_1 (tree decl, const char *name)
5261 varinfo_t vi, newvi;
5262 tree decl_type = TREE_TYPE (decl);
5263 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5264 VEC (fieldoff_s,heap) *fieldstack = NULL;
5269 || !host_integerp (declsize, 1))
5271 vi = new_var_info (decl, name);
5275 vi->is_unknown_size_var = true;
5276 vi->is_full_var = true;
5277 vi->may_have_pointers = could_have_pointers (decl);
5281 /* Collect field information. */
5282 if (use_field_sensitive
5283 && var_can_have_subvars (decl)
5284 /* ??? Force us to not use subfields for global initializers
5285 in IPA mode. Else we'd have to parse arbitrary initializers. */
5287 && is_global_var (decl)
5288 && DECL_INITIAL (decl)))
5290 fieldoff_s *fo = NULL;
5291 bool notokay = false;
5294 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5296 || DECL_EXTERNAL (decl)
5297 || TREE_ADDRESSABLE (decl));
5299 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5300 if (fo->has_unknown_size
5307 /* We can't sort them if we have a field with a variable sized type,
5308 which will make notokay = true. In that case, we are going to return
5309 without creating varinfos for the fields anyway, so sorting them is a
5313 sort_fieldstack (fieldstack);
5314 /* Due to some C++ FE issues, like PR 22488, we might end up
5315 what appear to be overlapping fields even though they,
5316 in reality, do not overlap. Until the C++ FE is fixed,
5317 we will simply disable field-sensitivity for these cases. */
5318 notokay = check_for_overlaps (fieldstack);
5322 VEC_free (fieldoff_s, heap, fieldstack);
5325 /* If we didn't end up collecting sub-variables create a full
5326 variable for the decl. */
5327 if (VEC_length (fieldoff_s, fieldstack) <= 1
5328 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5330 vi = new_var_info (decl, name);
5332 vi->may_have_pointers = could_have_pointers (decl);
5333 vi->fullsize = TREE_INT_CST_LOW (declsize);
5334 vi->size = vi->fullsize;
5335 vi->is_full_var = true;
5336 VEC_free (fieldoff_s, heap, fieldstack);
5340 vi = new_var_info (decl, name);
5341 vi->fullsize = TREE_INT_CST_LOW (declsize);
5342 for (i = 0, newvi = vi;
5343 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5344 ++i, newvi = newvi->next)
5346 const char *newname = "NULL";
5351 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5352 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5353 newname = ggc_strdup (tempname);
5356 newvi->name = newname;
5357 newvi->offset = fo->offset;
5358 newvi->size = fo->size;
5359 newvi->fullsize = vi->fullsize;
5360 newvi->may_have_pointers = fo->may_have_pointers;
5361 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5362 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5363 newvi->next = new_var_info (decl, name);
5366 VEC_free (fieldoff_s, heap, fieldstack);
5372 create_variable_info_for (tree decl, const char *name)
5374 varinfo_t vi = create_variable_info_for_1 (decl, name);
5375 unsigned int id = vi->id;
5377 insert_vi_for_tree (decl, vi);
5379 /* Create initial constraints for globals. */
5380 for (; vi; vi = vi->next)
5382 if (!vi->may_have_pointers
5383 || !vi->is_global_var)
5386 /* Mark global restrict qualified pointers. */
5387 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5388 && TYPE_RESTRICT (TREE_TYPE (decl)))
5389 || vi->only_restrict_pointers)
5390 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5392 /* For escaped variables initialize them from nonlocal. */
5394 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5395 make_copy_constraint (vi, nonlocal_id);
5397 /* If this is a global variable with an initializer and we are in
5398 IPA mode generate constraints for it. In non-IPA mode
5399 the initializer from nonlocal is all we need. */
5401 && DECL_INITIAL (decl))
5403 VEC (ce_s, heap) *rhsc = NULL;
5404 struct constraint_expr lhs, *rhsp;
5406 get_constraint_for (DECL_INITIAL (decl), &rhsc);
5410 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5411 process_constraint (new_constraint (lhs, *rhsp));
5412 /* If this is a variable that escapes from the unit
5413 the initializer escapes as well. */
5414 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5416 lhs.var = escaped_id;
5419 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5420 process_constraint (new_constraint (lhs, *rhsp));
5422 VEC_free (ce_s, heap, rhsc);
5429 /* Print out the points-to solution for VAR to FILE. */
5432 dump_solution_for_var (FILE *file, unsigned int var)
5434 varinfo_t vi = get_varinfo (var);
5438 /* Dump the solution for unified vars anyway, this avoids difficulties
5439 in scanning dumps in the testsuite. */
5440 fprintf (file, "%s = { ", vi->name);
5441 vi = get_varinfo (find (var));
5442 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5443 fprintf (file, "%s ", get_varinfo (i)->name);
5444 fprintf (file, "}");
5446 /* But note when the variable was unified. */
5448 fprintf (file, " same as %s", vi->name);
5450 fprintf (file, "\n");
5453 /* Print the points-to solution for VAR to stdout. */
5456 debug_solution_for_var (unsigned int var)
5458 dump_solution_for_var (stdout, var);
5461 /* Create varinfo structures for all of the variables in the
5462 function for intraprocedural mode. */
5465 intra_create_variable_infos (void)
5469 /* For each incoming pointer argument arg, create the constraint ARG
5470 = NONLOCAL or a dummy variable if it is a restrict qualified
5471 passed-by-reference argument. */
5472 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
5476 if (!could_have_pointers (t))
5479 /* For restrict qualified pointers to objects passed by
5480 reference build a real representative for the pointed-to object. */
5481 if (DECL_BY_REFERENCE (t)
5482 && POINTER_TYPE_P (TREE_TYPE (t))
5483 && TYPE_RESTRICT (TREE_TYPE (t)))
5485 struct constraint_expr lhsc, rhsc;
5487 tree heapvar = heapvar_lookup (t, 0);
5488 if (heapvar == NULL_TREE)
5491 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5493 DECL_EXTERNAL (heapvar) = 1;
5494 heapvar_insert (t, 0, heapvar);
5495 ann = get_var_ann (heapvar);
5496 ann->is_heapvar = 1;
5498 if (gimple_referenced_vars (cfun))
5499 add_referenced_var (heapvar);
5500 lhsc.var = get_vi_for_tree (t)->id;
5503 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5504 rhsc.type = ADDRESSOF;
5506 process_constraint (new_constraint (lhsc, rhsc));
5507 vi->is_restrict_var = 1;
5511 for (p = get_vi_for_tree (t); p; p = p->next)
5513 if (p->may_have_pointers)
5514 make_constraint_from (p, nonlocal_id);
5515 if (p->only_restrict_pointers)
5516 make_constraint_from_restrict (p, "PARM_RESTRICT");
5518 if (POINTER_TYPE_P (TREE_TYPE (t))
5519 && TYPE_RESTRICT (TREE_TYPE (t)))
5520 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5523 /* Add a constraint for a result decl that is passed by reference. */
5524 if (DECL_RESULT (cfun->decl)
5525 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5527 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5529 for (p = result_vi; p; p = p->next)
5530 make_constraint_from (p, nonlocal_id);
5533 /* Add a constraint for the incoming static chain parameter. */
5534 if (cfun->static_chain_decl != NULL_TREE)
5536 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5538 for (p = chain_vi; p; p = p->next)
5539 make_constraint_from (p, nonlocal_id);
5543 /* Structure used to put solution bitmaps in a hashtable so they can
5544 be shared among variables with the same points-to set. */
5546 typedef struct shared_bitmap_info
5550 } *shared_bitmap_info_t;
5551 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5553 static htab_t shared_bitmap_table;
5555 /* Hash function for a shared_bitmap_info_t */
5558 shared_bitmap_hash (const void *p)
5560 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5561 return bi->hashcode;
5564 /* Equality function for two shared_bitmap_info_t's. */
5567 shared_bitmap_eq (const void *p1, const void *p2)
5569 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5570 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5571 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5574 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5575 existing instance if there is one, NULL otherwise. */
5578 shared_bitmap_lookup (bitmap pt_vars)
5581 struct shared_bitmap_info sbi;
5583 sbi.pt_vars = pt_vars;
5584 sbi.hashcode = bitmap_hash (pt_vars);
5586 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5587 sbi.hashcode, NO_INSERT);
5591 return ((shared_bitmap_info_t) *slot)->pt_vars;
5595 /* Add a bitmap to the shared bitmap hashtable. */
5598 shared_bitmap_add (bitmap pt_vars)
5601 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5603 sbi->pt_vars = pt_vars;
5604 sbi->hashcode = bitmap_hash (pt_vars);
5606 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5607 sbi->hashcode, INSERT);
5608 gcc_assert (!*slot);
5609 *slot = (void *) sbi;
5613 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5616 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5621 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5623 varinfo_t vi = get_varinfo (i);
5625 /* The only artificial variables that are allowed in a may-alias
5626 set are heap variables. */
5627 if (vi->is_artificial_var && !vi->is_heap_var)
5630 if (TREE_CODE (vi->decl) == VAR_DECL
5631 || TREE_CODE (vi->decl) == PARM_DECL
5632 || TREE_CODE (vi->decl) == RESULT_DECL)
5634 /* If we are in IPA mode we will not recompute points-to
5635 sets after inlining so make sure they stay valid. */
5637 && !DECL_PT_UID_SET_P (vi->decl))
5638 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5640 /* Add the decl to the points-to set. Note that the points-to
5641 set contains global variables. */
5642 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5643 if (vi->is_global_var)
5644 pt->vars_contains_global = true;
5650 /* Compute the points-to solution *PT for the variable VI. */
5653 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5657 bitmap finished_solution;
5661 memset (pt, 0, sizeof (struct pt_solution));
5663 /* This variable may have been collapsed, let's get the real
5665 vi = get_varinfo (find (orig_vi->id));
5667 /* Translate artificial variables into SSA_NAME_PTR_INFO
5669 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5671 varinfo_t vi = get_varinfo (i);
5673 if (vi->is_artificial_var)
5675 if (vi->id == nothing_id)
5677 else if (vi->id == escaped_id)
5680 pt->ipa_escaped = 1;
5684 else if (vi->id == nonlocal_id)
5686 else if (vi->is_heap_var)
5687 /* We represent heapvars in the points-to set properly. */
5689 else if (vi->id == readonly_id)
5692 else if (vi->id == anything_id
5693 || vi->id == integer_id)
5696 if (vi->is_restrict_var)
5697 pt->vars_contains_restrict = true;
5700 /* Instead of doing extra work, simply do not create
5701 elaborate points-to information for pt_anything pointers. */
5703 && (orig_vi->is_artificial_var
5704 || !pt->vars_contains_restrict))
5707 /* Share the final set of variables when possible. */
5708 finished_solution = BITMAP_GGC_ALLOC ();
5709 stats.points_to_sets_created++;
5711 set_uids_in_ptset (finished_solution, vi->solution, pt);
5712 result = shared_bitmap_lookup (finished_solution);
5715 shared_bitmap_add (finished_solution);
5716 pt->vars = finished_solution;
5721 bitmap_clear (finished_solution);
5725 /* Given a pointer variable P, fill in its points-to set. */
5728 find_what_p_points_to (tree p)
5730 struct ptr_info_def *pi;
5734 /* For parameters, get at the points-to set for the actual parm
5736 if (TREE_CODE (p) == SSA_NAME
5737 && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5738 && SSA_NAME_IS_DEFAULT_DEF (p))
5739 lookup_p = SSA_NAME_VAR (p);
5741 vi = lookup_vi_for_tree (lookup_p);
5745 pi = get_ptr_info (p);
5746 find_what_var_points_to (vi, &pi->pt);
5750 /* Query statistics for points-to solutions. */
5753 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5754 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5755 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5756 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5760 dump_pta_stats (FILE *s)
5762 fprintf (s, "\nPTA query stats:\n");
5763 fprintf (s, " pt_solution_includes: "
5764 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5765 HOST_WIDE_INT_PRINT_DEC" queries\n",
5766 pta_stats.pt_solution_includes_no_alias,
5767 pta_stats.pt_solution_includes_no_alias
5768 + pta_stats.pt_solution_includes_may_alias);
5769 fprintf (s, " pt_solutions_intersect: "
5770 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5771 HOST_WIDE_INT_PRINT_DEC" queries\n",
5772 pta_stats.pt_solutions_intersect_no_alias,
5773 pta_stats.pt_solutions_intersect_no_alias
5774 + pta_stats.pt_solutions_intersect_may_alias);
5778 /* Reset the points-to solution *PT to a conservative default
5779 (point to anything). */
5782 pt_solution_reset (struct pt_solution *pt)
5784 memset (pt, 0, sizeof (struct pt_solution));
5785 pt->anything = true;
5788 /* Set the points-to solution *PT to point only to the variables
5789 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5790 global variables and VARS_CONTAINS_RESTRICT specifies whether
5791 it contains restrict tag variables. */
5794 pt_solution_set (struct pt_solution *pt, bitmap vars,
5795 bool vars_contains_global, bool vars_contains_restrict)
5797 memset (pt, 0, sizeof (struct pt_solution));
5799 pt->vars_contains_global = vars_contains_global;
5800 pt->vars_contains_restrict = vars_contains_restrict;
5803 /* Computes the union of the points-to solutions *DEST and *SRC and
5804 stores the result in *DEST. This changes the points-to bitmap
5805 of *DEST and thus may not be used if that might be shared.
5806 The points-to bitmap of *SRC and *DEST will not be shared after
5807 this function if they were not before. */
5810 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5812 dest->anything |= src->anything;
5815 pt_solution_reset (dest);
5819 dest->nonlocal |= src->nonlocal;
5820 dest->escaped |= src->escaped;
5821 dest->ipa_escaped |= src->ipa_escaped;
5822 dest->null |= src->null;
5823 dest->vars_contains_global |= src->vars_contains_global;
5824 dest->vars_contains_restrict |= src->vars_contains_restrict;
5829 dest->vars = BITMAP_GGC_ALLOC ();
5830 bitmap_ior_into (dest->vars, src->vars);
5833 /* Return true if the points-to solution *PT is empty. */
5836 pt_solution_empty_p (struct pt_solution *pt)
5843 && !bitmap_empty_p (pt->vars))
5846 /* If the solution includes ESCAPED, check if that is empty. */
5848 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5851 /* If the solution includes ESCAPED, check if that is empty. */
5853 && !pt_solution_empty_p (&ipa_escaped_pt))
5859 /* Return true if the points-to solution *PT includes global memory. */
5862 pt_solution_includes_global (struct pt_solution *pt)
5866 || pt->vars_contains_global)
5870 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5872 if (pt->ipa_escaped)
5873 return pt_solution_includes_global (&ipa_escaped_pt);
5875 /* ??? This predicate is not correct for the IPA-PTA solution
5876 as we do not properly distinguish between unit escape points
5877 and global variables. */
5878 if (cfun->gimple_df->ipa_pta)
5884 /* Return true if the points-to solution *PT includes the variable
5885 declaration DECL. */
5888 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5894 && is_global_var (decl))
5898 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5901 /* If the solution includes ESCAPED, check it. */
5903 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5906 /* If the solution includes ESCAPED, check it. */
5908 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5915 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5917 bool res = pt_solution_includes_1 (pt, decl);
5919 ++pta_stats.pt_solution_includes_may_alias;
5921 ++pta_stats.pt_solution_includes_no_alias;
5925 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5929 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5931 if (pt1->anything || pt2->anything)
5934 /* If either points to unknown global memory and the other points to
5935 any global memory they alias. */
5938 || pt2->vars_contains_global))
5940 && pt1->vars_contains_global))
5943 /* Check the escaped solution if required. */
5944 if ((pt1->escaped || pt2->escaped)
5945 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5947 /* If both point to escaped memory and that solution
5948 is not empty they alias. */
5949 if (pt1->escaped && pt2->escaped)
5952 /* If either points to escaped memory see if the escaped solution
5953 intersects with the other. */
5955 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5957 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
5961 /* Check the escaped solution if required.
5962 ??? Do we need to check the local against the IPA escaped sets? */
5963 if ((pt1->ipa_escaped || pt2->ipa_escaped)
5964 && !pt_solution_empty_p (&ipa_escaped_pt))
5966 /* If both point to escaped memory and that solution
5967 is not empty they alias. */
5968 if (pt1->ipa_escaped && pt2->ipa_escaped)
5971 /* If either points to escaped memory see if the escaped solution
5972 intersects with the other. */
5973 if ((pt1->ipa_escaped
5974 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
5975 || (pt2->ipa_escaped
5976 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
5980 /* Now both pointers alias if their points-to solution intersects. */
5983 && bitmap_intersect_p (pt1->vars, pt2->vars));
5987 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
5989 bool res = pt_solutions_intersect_1 (pt1, pt2);
5991 ++pta_stats.pt_solutions_intersect_may_alias;
5993 ++pta_stats.pt_solutions_intersect_no_alias;
5997 /* Return true if both points-to solutions PT1 and PT2 for two restrict
5998 qualified pointers are possibly based on the same pointer. */
6001 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6002 struct pt_solution *pt2)
6004 /* If we deal with points-to solutions of two restrict qualified
6005 pointers solely rely on the pointed-to variable bitmap intersection.
6006 For two pointers that are based on each other the bitmaps will
6008 if (pt1->vars_contains_restrict
6009 && pt2->vars_contains_restrict)
6011 gcc_assert (pt1->vars && pt2->vars);
6012 return bitmap_intersect_p (pt1->vars, pt2->vars);
6019 /* Dump points-to information to OUTFILE. */
6022 dump_sa_points_to_info (FILE *outfile)
6026 fprintf (outfile, "\nPoints-to sets\n\n");
6028 if (dump_flags & TDF_STATS)
6030 fprintf (outfile, "Stats:\n");
6031 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6032 fprintf (outfile, "Non-pointer vars: %d\n",
6033 stats.nonpointer_vars);
6034 fprintf (outfile, "Statically unified vars: %d\n",
6035 stats.unified_vars_static);
6036 fprintf (outfile, "Dynamically unified vars: %d\n",
6037 stats.unified_vars_dynamic);
6038 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6039 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6040 fprintf (outfile, "Number of implicit edges: %d\n",
6041 stats.num_implicit_edges);
6044 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6046 varinfo_t vi = get_varinfo (i);
6047 if (!vi->may_have_pointers)
6049 dump_solution_for_var (outfile, i);
6054 /* Debug points-to information to stderr. */
6057 debug_sa_points_to_info (void)
6059 dump_sa_points_to_info (stderr);
6063 /* Initialize the always-existing constraint variables for NULL
6064 ANYTHING, READONLY, and INTEGER */
6067 init_base_vars (void)
6069 struct constraint_expr lhs, rhs;
6070 varinfo_t var_anything;
6071 varinfo_t var_nothing;
6072 varinfo_t var_readonly;
6073 varinfo_t var_escaped;
6074 varinfo_t var_nonlocal;
6075 varinfo_t var_storedanything;
6076 varinfo_t var_integer;
6078 /* Create the NULL variable, used to represent that a variable points
6080 var_nothing = new_var_info (NULL_TREE, "NULL");
6081 gcc_assert (var_nothing->id == nothing_id);
6082 var_nothing->is_artificial_var = 1;
6083 var_nothing->offset = 0;
6084 var_nothing->size = ~0;
6085 var_nothing->fullsize = ~0;
6086 var_nothing->is_special_var = 1;
6087 var_nothing->may_have_pointers = 0;
6088 var_nothing->is_global_var = 0;
6090 /* Create the ANYTHING variable, used to represent that a variable
6091 points to some unknown piece of memory. */
6092 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6093 gcc_assert (var_anything->id == anything_id);
6094 var_anything->is_artificial_var = 1;
6095 var_anything->size = ~0;
6096 var_anything->offset = 0;
6097 var_anything->next = NULL;
6098 var_anything->fullsize = ~0;
6099 var_anything->is_special_var = 1;
6101 /* Anything points to anything. This makes deref constraints just
6102 work in the presence of linked list and other p = *p type loops,
6103 by saying that *ANYTHING = ANYTHING. */
6105 lhs.var = anything_id;
6107 rhs.type = ADDRESSOF;
6108 rhs.var = anything_id;
6111 /* This specifically does not use process_constraint because
6112 process_constraint ignores all anything = anything constraints, since all
6113 but this one are redundant. */
6114 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6116 /* Create the READONLY variable, used to represent that a variable
6117 points to readonly memory. */
6118 var_readonly = new_var_info (NULL_TREE, "READONLY");
6119 gcc_assert (var_readonly->id == readonly_id);
6120 var_readonly->is_artificial_var = 1;
6121 var_readonly->offset = 0;
6122 var_readonly->size = ~0;
6123 var_readonly->fullsize = ~0;
6124 var_readonly->next = NULL;
6125 var_readonly->is_special_var = 1;
6127 /* readonly memory points to anything, in order to make deref
6128 easier. In reality, it points to anything the particular
6129 readonly variable can point to, but we don't track this
6132 lhs.var = readonly_id;
6134 rhs.type = ADDRESSOF;
6135 rhs.var = readonly_id; /* FIXME */
6137 process_constraint (new_constraint (lhs, rhs));
6139 /* Create the ESCAPED variable, used to represent the set of escaped
6141 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6142 gcc_assert (var_escaped->id == escaped_id);
6143 var_escaped->is_artificial_var = 1;
6144 var_escaped->offset = 0;
6145 var_escaped->size = ~0;
6146 var_escaped->fullsize = ~0;
6147 var_escaped->is_special_var = 0;
6149 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6151 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6152 gcc_assert (var_nonlocal->id == nonlocal_id);
6153 var_nonlocal->is_artificial_var = 1;
6154 var_nonlocal->offset = 0;
6155 var_nonlocal->size = ~0;
6156 var_nonlocal->fullsize = ~0;
6157 var_nonlocal->is_special_var = 1;
6159 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6161 lhs.var = escaped_id;
6164 rhs.var = escaped_id;
6166 process_constraint (new_constraint (lhs, rhs));
6168 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6169 whole variable escapes. */
6171 lhs.var = escaped_id;
6174 rhs.var = escaped_id;
6175 rhs.offset = UNKNOWN_OFFSET;
6176 process_constraint (new_constraint (lhs, rhs));
6178 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6179 everything pointed to by escaped points to what global memory can
6182 lhs.var = escaped_id;
6185 rhs.var = nonlocal_id;
6187 process_constraint (new_constraint (lhs, rhs));
6189 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6190 global memory may point to global memory and escaped memory. */
6192 lhs.var = nonlocal_id;
6194 rhs.type = ADDRESSOF;
6195 rhs.var = nonlocal_id;
6197 process_constraint (new_constraint (lhs, rhs));
6198 rhs.type = ADDRESSOF;
6199 rhs.var = escaped_id;
6201 process_constraint (new_constraint (lhs, rhs));
6203 /* Create the STOREDANYTHING variable, used to represent the set of
6204 variables stored to *ANYTHING. */
6205 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6206 gcc_assert (var_storedanything->id == storedanything_id);
6207 var_storedanything->is_artificial_var = 1;
6208 var_storedanything->offset = 0;
6209 var_storedanything->size = ~0;
6210 var_storedanything->fullsize = ~0;
6211 var_storedanything->is_special_var = 0;
6213 /* Create the INTEGER variable, used to represent that a variable points
6214 to what an INTEGER "points to". */
6215 var_integer = new_var_info (NULL_TREE, "INTEGER");
6216 gcc_assert (var_integer->id == integer_id);
6217 var_integer->is_artificial_var = 1;
6218 var_integer->size = ~0;
6219 var_integer->fullsize = ~0;
6220 var_integer->offset = 0;
6221 var_integer->next = NULL;
6222 var_integer->is_special_var = 1;
6224 /* INTEGER = ANYTHING, because we don't know where a dereference of
6225 a random integer will point to. */
6227 lhs.var = integer_id;
6229 rhs.type = ADDRESSOF;
6230 rhs.var = anything_id;
6232 process_constraint (new_constraint (lhs, rhs));
6235 /* Initialize things necessary to perform PTA */
6238 init_alias_vars (void)
6240 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6242 bitmap_obstack_initialize (&pta_obstack);
6243 bitmap_obstack_initialize (&oldpta_obstack);
6244 bitmap_obstack_initialize (&predbitmap_obstack);
6246 constraint_pool = create_alloc_pool ("Constraint pool",
6247 sizeof (struct constraint), 30);
6248 variable_info_pool = create_alloc_pool ("Variable info pool",
6249 sizeof (struct variable_info), 30);
6250 constraints = VEC_alloc (constraint_t, heap, 8);
6251 varmap = VEC_alloc (varinfo_t, heap, 8);
6252 vi_for_tree = pointer_map_create ();
6253 call_stmt_vars = pointer_map_create ();
6255 memset (&stats, 0, sizeof (stats));
6256 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6257 shared_bitmap_eq, free);
6261 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6262 predecessor edges. */
6265 remove_preds_and_fake_succs (constraint_graph_t graph)
6269 /* Clear the implicit ref and address nodes from the successor
6271 for (i = 0; i < FIRST_REF_NODE; i++)
6273 if (graph->succs[i])
6274 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6275 FIRST_REF_NODE * 2);
6278 /* Free the successor list for the non-ref nodes. */
6279 for (i = FIRST_REF_NODE; i < graph->size; i++)
6281 if (graph->succs[i])
6282 BITMAP_FREE (graph->succs[i]);
6285 /* Now reallocate the size of the successor list as, and blow away
6286 the predecessor bitmaps. */
6287 graph->size = VEC_length (varinfo_t, varmap);
6288 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6290 free (graph->implicit_preds);
6291 graph->implicit_preds = NULL;
6292 free (graph->preds);
6293 graph->preds = NULL;
6294 bitmap_obstack_release (&predbitmap_obstack);
6297 /* Initialize the heapvar for statement mapping. */
6300 init_alias_heapvars (void)
6302 if (!heapvar_for_stmt)
6303 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6307 /* Delete the heapvar for statement mapping. */
6310 delete_alias_heapvars (void)
6312 if (heapvar_for_stmt)
6313 htab_delete (heapvar_for_stmt);
6314 heapvar_for_stmt = NULL;
6317 /* Solve the constraint set. */
6320 solve_constraints (void)
6322 struct scc_info *si;
6326 "\nCollapsing static cycles and doing variable "
6329 init_graph (VEC_length (varinfo_t, varmap) * 2);
6332 fprintf (dump_file, "Building predecessor graph\n");
6333 build_pred_graph ();
6336 fprintf (dump_file, "Detecting pointer and location "
6338 si = perform_var_substitution (graph);
6341 fprintf (dump_file, "Rewriting constraints and unifying "
6343 rewrite_constraints (graph, si);
6345 build_succ_graph ();
6346 free_var_substitution_info (si);
6348 if (dump_file && (dump_flags & TDF_GRAPH))
6349 dump_constraint_graph (dump_file);
6351 move_complex_constraints (graph);
6354 fprintf (dump_file, "Uniting pointer but not location equivalent "
6356 unite_pointer_equivalences (graph);
6359 fprintf (dump_file, "Finding indirect cycles\n");
6360 find_indirect_cycles (graph);
6362 /* Implicit nodes and predecessors are no longer necessary at this
6364 remove_preds_and_fake_succs (graph);
6367 fprintf (dump_file, "Solving graph\n");
6369 solve_graph (graph);
6372 dump_sa_points_to_info (dump_file);
6375 /* Create points-to sets for the current function. See the comments
6376 at the start of the file for an algorithmic overview. */
6379 compute_points_to_sets (void)
6385 timevar_push (TV_TREE_PTA);
6388 init_alias_heapvars ();
6390 intra_create_variable_infos ();
6392 /* Now walk all statements and build the constraint set. */
6395 gimple_stmt_iterator gsi;
6397 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6399 gimple phi = gsi_stmt (gsi);
6401 if (is_gimple_reg (gimple_phi_result (phi)))
6402 find_func_aliases (phi);
6405 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6407 gimple stmt = gsi_stmt (gsi);
6409 find_func_aliases (stmt);
6415 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6416 dump_constraints (dump_file, 0);
6419 /* From the constraints compute the points-to sets. */
6420 solve_constraints ();
6422 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6423 find_what_var_points_to (get_varinfo (escaped_id),
6424 &cfun->gimple_df->escaped);
6426 /* Make sure the ESCAPED solution (which is used as placeholder in
6427 other solutions) does not reference itself. This simplifies
6428 points-to solution queries. */
6429 cfun->gimple_df->escaped.escaped = 0;
6431 /* Mark escaped HEAP variables as global. */
6432 for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); ++i)
6434 && !vi->is_restrict_var
6435 && !vi->is_global_var)
6436 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6437 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6439 /* Compute the points-to sets for pointer SSA_NAMEs. */
6440 for (i = 0; i < num_ssa_names; ++i)
6442 tree ptr = ssa_name (i);
6444 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6445 find_what_p_points_to (ptr);
6448 /* Compute the call-used/clobbered sets. */
6451 gimple_stmt_iterator gsi;
6453 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6455 gimple stmt = gsi_stmt (gsi);
6456 struct pt_solution *pt;
6457 if (!is_gimple_call (stmt))
6460 pt = gimple_call_use_set (stmt);
6461 if (gimple_call_flags (stmt) & ECF_CONST)
6462 memset (pt, 0, sizeof (struct pt_solution));
6463 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6465 find_what_var_points_to (vi, pt);
6466 /* Escaped (and thus nonlocal) variables are always
6467 implicitly used by calls. */
6468 /* ??? ESCAPED can be empty even though NONLOCAL
6475 /* If there is nothing special about this call then
6476 we have made everything that is used also escape. */
6477 *pt = cfun->gimple_df->escaped;
6481 pt = gimple_call_clobber_set (stmt);
6482 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6483 memset (pt, 0, sizeof (struct pt_solution));
6484 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6486 find_what_var_points_to (vi, pt);
6487 /* Escaped (and thus nonlocal) variables are always
6488 implicitly clobbered by calls. */
6489 /* ??? ESCAPED can be empty even though NONLOCAL
6496 /* If there is nothing special about this call then
6497 we have made everything that is used also escape. */
6498 *pt = cfun->gimple_df->escaped;
6504 timevar_pop (TV_TREE_PTA);
6508 /* Delete created points-to sets. */
6511 delete_points_to_sets (void)
6515 htab_delete (shared_bitmap_table);
6516 if (dump_file && (dump_flags & TDF_STATS))
6517 fprintf (dump_file, "Points to sets created:%d\n",
6518 stats.points_to_sets_created);
6520 pointer_map_destroy (vi_for_tree);
6521 pointer_map_destroy (call_stmt_vars);
6522 bitmap_obstack_release (&pta_obstack);
6523 VEC_free (constraint_t, heap, constraints);
6525 for (i = 0; i < graph->size; i++)
6526 VEC_free (constraint_t, heap, graph->complex[i]);
6527 free (graph->complex);
6530 free (graph->succs);
6532 free (graph->pe_rep);
6533 free (graph->indirect_cycles);
6536 VEC_free (varinfo_t, heap, varmap);
6537 free_alloc_pool (variable_info_pool);
6538 free_alloc_pool (constraint_pool);
6542 /* Compute points-to information for every SSA_NAME pointer in the
6543 current function and compute the transitive closure of escaped
6544 variables to re-initialize the call-clobber states of local variables. */
6547 compute_may_aliases (void)
6549 if (cfun->gimple_df->ipa_pta)
6553 fprintf (dump_file, "\nNot re-computing points-to information "
6554 "because IPA points-to information is available.\n\n");
6556 /* But still dump what we have remaining it. */
6557 dump_alias_info (dump_file);
6559 if (dump_flags & TDF_DETAILS)
6560 dump_referenced_vars (dump_file);
6566 /* For each pointer P_i, determine the sets of variables that P_i may
6567 point-to. Compute the reachability set of escaped and call-used
6569 compute_points_to_sets ();
6571 /* Debugging dumps. */
6574 dump_alias_info (dump_file);
6576 if (dump_flags & TDF_DETAILS)
6577 dump_referenced_vars (dump_file);
6580 /* Deallocate memory used by aliasing data structures and the internal
6581 points-to solution. */
6582 delete_points_to_sets ();
6584 gcc_assert (!need_ssa_update_p (cfun));
6590 gate_tree_pta (void)
6592 return flag_tree_pta;
6595 /* A dummy pass to cause points-to information to be computed via
6596 TODO_rebuild_alias. */
6598 struct gimple_opt_pass pass_build_alias =
6603 gate_tree_pta, /* gate */
6607 0, /* static_pass_number */
6608 TV_NONE, /* tv_id */
6609 PROP_cfg | PROP_ssa, /* properties_required */
6610 0, /* properties_provided */
6611 0, /* properties_destroyed */
6612 0, /* todo_flags_start */
6613 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6617 /* A dummy pass to cause points-to information to be computed via
6618 TODO_rebuild_alias. */
6620 struct gimple_opt_pass pass_build_ealias =
6624 "ealias", /* name */
6625 gate_tree_pta, /* gate */
6629 0, /* static_pass_number */
6630 TV_NONE, /* tv_id */
6631 PROP_cfg | PROP_ssa, /* properties_required */
6632 0, /* properties_provided */
6633 0, /* properties_destroyed */
6634 0, /* todo_flags_start */
6635 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6640 /* Return true if we should execute IPA PTA. */
6646 /* Don't bother doing anything if the program has errors. */
6650 /* IPA PTA solutions for ESCAPED. */
6651 struct pt_solution ipa_escaped_pt
6652 = { true, false, false, false, false, false, false, NULL };
6654 /* Execute the driver for IPA PTA. */
6656 ipa_pta_execute (void)
6658 struct cgraph_node *node;
6659 struct varpool_node *var;
6664 init_alias_heapvars ();
6667 /* Build the constraints. */
6668 for (node = cgraph_nodes; node; node = node->next)
6670 struct cgraph_node *alias;
6673 /* Nodes without a body are not interesting. Especially do not
6674 visit clones at this point for now - we get duplicate decls
6675 there for inline clones at least. */
6676 if (!gimple_has_body_p (node->decl)
6680 vi = create_function_info_for (node->decl,
6681 alias_get_name (node->decl));
6683 /* Associate the varinfo node with all aliases. */
6684 for (alias = node->same_body; alias; alias = alias->next)
6685 insert_vi_for_tree (alias->decl, vi);
6688 /* Create constraints for global variables and their initializers. */
6689 for (var = varpool_nodes; var; var = var->next)
6691 struct varpool_node *alias;
6694 vi = get_vi_for_tree (var->decl);
6696 /* Associate the varinfo node with all aliases. */
6697 for (alias = var->extra_name; alias; alias = alias->next)
6698 insert_vi_for_tree (alias->decl, vi);
6704 "Generating constraints for global initializers\n\n");
6705 dump_constraints (dump_file, 0);
6706 fprintf (dump_file, "\n");
6708 from = VEC_length (constraint_t, constraints);
6710 for (node = cgraph_nodes; node; node = node->next)
6712 struct function *func;
6716 /* Nodes without a body are not interesting. */
6717 if (!gimple_has_body_p (node->decl)
6724 "Generating constraints for %s", cgraph_node_name (node));
6725 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6726 fprintf (dump_file, " (%s)",
6727 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6728 fprintf (dump_file, "\n");
6731 func = DECL_STRUCT_FUNCTION (node->decl);
6732 old_func_decl = current_function_decl;
6734 current_function_decl = node->decl;
6736 /* For externally visible functions use local constraints for
6737 their arguments. For local functions we see all callers
6738 and thus do not need initial constraints for parameters. */
6739 if (node->local.externally_visible)
6740 intra_create_variable_infos ();
6742 /* Build constriants for the function body. */
6743 FOR_EACH_BB_FN (bb, func)
6745 gimple_stmt_iterator gsi;
6747 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6750 gimple phi = gsi_stmt (gsi);
6752 if (is_gimple_reg (gimple_phi_result (phi)))
6753 find_func_aliases (phi);
6756 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6758 gimple stmt = gsi_stmt (gsi);
6760 find_func_aliases (stmt);
6761 find_func_clobbers (stmt);
6765 current_function_decl = old_func_decl;
6770 fprintf (dump_file, "\n");
6771 dump_constraints (dump_file, from);
6772 fprintf (dump_file, "\n");
6774 from = VEC_length (constraint_t, constraints);
6777 /* From the constraints compute the points-to sets. */
6778 solve_constraints ();
6780 /* Compute the global points-to sets for ESCAPED.
6781 ??? Note that the computed escape set is not correct
6782 for the whole unit as we fail to consider graph edges to
6783 externally visible functions. */
6784 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6786 /* Make sure the ESCAPED solution (which is used as placeholder in
6787 other solutions) does not reference itself. This simplifies
6788 points-to solution queries. */
6789 ipa_escaped_pt.ipa_escaped = 0;
6791 /* Assign the points-to sets to the SSA names in the unit. */
6792 for (node = cgraph_nodes; node; node = node->next)
6795 struct function *fn;
6799 struct pt_solution uses, clobbers;
6800 struct cgraph_edge *e;
6802 /* Nodes without a body are not interesting. */
6803 if (!gimple_has_body_p (node->decl)
6807 fn = DECL_STRUCT_FUNCTION (node->decl);
6809 /* Compute the points-to sets for pointer SSA_NAMEs. */
6810 for (i = 0; VEC_iterate (tree, fn->gimple_df->ssa_names, i, ptr); ++i)
6813 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6814 find_what_p_points_to (ptr);
6817 /* Compute the call-use and call-clobber sets for all direct calls. */
6818 fi = lookup_vi_for_tree (node->decl);
6819 gcc_assert (fi->is_fn_info);
6820 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6822 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6823 for (e = node->callers; e; e = e->next_caller)
6828 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6829 *gimple_call_use_set (e->call_stmt) = uses;
6832 /* Compute the call-use and call-clobber sets for indirect calls
6833 and calls to external functions. */
6834 FOR_EACH_BB_FN (bb, fn)
6836 gimple_stmt_iterator gsi;
6838 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6840 gimple stmt = gsi_stmt (gsi);
6841 struct pt_solution *pt;
6845 if (!is_gimple_call (stmt))
6848 /* Handle direct calls to external functions. */
6849 decl = gimple_call_fndecl (stmt);
6851 && (!(fi = lookup_vi_for_tree (decl))
6852 || !fi->is_fn_info))
6854 pt = gimple_call_use_set (stmt);
6855 if (gimple_call_flags (stmt) & ECF_CONST)
6856 memset (pt, 0, sizeof (struct pt_solution));
6857 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6859 find_what_var_points_to (vi, pt);
6860 /* Escaped (and thus nonlocal) variables are always
6861 implicitly used by calls. */
6862 /* ??? ESCAPED can be empty even though NONLOCAL
6865 pt->ipa_escaped = 1;
6869 /* If there is nothing special about this call then
6870 we have made everything that is used also escape. */
6871 *pt = ipa_escaped_pt;
6875 pt = gimple_call_clobber_set (stmt);
6876 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6877 memset (pt, 0, sizeof (struct pt_solution));
6878 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6880 find_what_var_points_to (vi, pt);
6881 /* Escaped (and thus nonlocal) variables are always
6882 implicitly clobbered by calls. */
6883 /* ??? ESCAPED can be empty even though NONLOCAL
6886 pt->ipa_escaped = 1;
6890 /* If there is nothing special about this call then
6891 we have made everything that is used also escape. */
6892 *pt = ipa_escaped_pt;
6897 /* Handle indirect calls. */
6899 && (fi = get_fi_for_callee (stmt)))
6901 /* We need to accumulate all clobbers/uses of all possible
6903 fi = get_varinfo (find (fi->id));
6904 /* If we cannot constrain the set of functions we'll end up
6905 calling we end up using/clobbering everything. */
6906 if (bitmap_bit_p (fi->solution, anything_id)
6907 || bitmap_bit_p (fi->solution, nonlocal_id)
6908 || bitmap_bit_p (fi->solution, escaped_id))
6910 pt_solution_reset (gimple_call_clobber_set (stmt));
6911 pt_solution_reset (gimple_call_use_set (stmt));
6917 struct pt_solution *uses, *clobbers;
6919 uses = gimple_call_use_set (stmt);
6920 clobbers = gimple_call_clobber_set (stmt);
6921 memset (uses, 0, sizeof (struct pt_solution));
6922 memset (clobbers, 0, sizeof (struct pt_solution));
6923 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6925 struct pt_solution sol;
6927 vi = get_varinfo (i);
6928 if (!vi->is_fn_info)
6930 /* ??? We could be more precise here? */
6932 uses->ipa_escaped = 1;
6933 clobbers->nonlocal = 1;
6934 clobbers->ipa_escaped = 1;
6938 if (!uses->anything)
6940 find_what_var_points_to
6941 (first_vi_for_offset (vi, fi_uses), &sol);
6942 pt_solution_ior_into (uses, &sol);
6944 if (!clobbers->anything)
6946 find_what_var_points_to
6947 (first_vi_for_offset (vi, fi_clobbers), &sol);
6948 pt_solution_ior_into (clobbers, &sol);
6956 fn->gimple_df->ipa_pta = true;
6959 delete_points_to_sets ();
6966 struct simple_ipa_opt_pass pass_ipa_pta =
6971 gate_ipa_pta, /* gate */
6972 ipa_pta_execute, /* execute */
6975 0, /* static_pass_number */
6976 TV_IPA_PTA, /* tv_id */
6977 0, /* properties_required */
6978 0, /* properties_provided */
6979 0, /* properties_destroyed */
6980 0, /* todo_flags_start */
6981 TODO_update_ssa /* todo_flags_finish */
6986 #include "gt-tree-ssa-structalias.h"