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"
32 #include "hard-reg-set.h"
33 #include "basic-block.h"
36 #include "tree-flow.h"
37 #include "tree-inline.h"
38 #include "diagnostic.h"
44 #include "tree-pass.h"
46 #include "alloc-pool.h"
47 #include "splay-tree.h"
51 #include "pointer-set.h"
53 /* The idea behind this analyzer is to generate set constraints from the
54 program, then solve the resulting constraints in order to generate the
57 Set constraints are a way of modeling program analysis problems that
58 involve sets. They consist of an inclusion constraint language,
59 describing the variables (each variable is a set) and operations that
60 are involved on the variables, and a set of rules that derive facts
61 from these operations. To solve a system of set constraints, you derive
62 all possible facts under the rules, which gives you the correct sets
65 See "Efficient Field-sensitive pointer analysis for C" by "David
66 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
67 http://citeseer.ist.psu.edu/pearce04efficient.html
69 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
70 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
71 http://citeseer.ist.psu.edu/heintze01ultrafast.html
73 There are three types of real constraint expressions, DEREF,
74 ADDRESSOF, and SCALAR. Each constraint expression consists
75 of a constraint type, a variable, and an offset.
77 SCALAR is a constraint expression type used to represent x, whether
78 it appears on the LHS or the RHS of a statement.
79 DEREF is a constraint expression type used to represent *x, whether
80 it appears on the LHS or the RHS of a statement.
81 ADDRESSOF is a constraint expression used to represent &x, whether
82 it appears on the LHS or the RHS of a statement.
84 Each pointer variable in the program is assigned an integer id, and
85 each field of a structure variable is assigned an integer id as well.
87 Structure variables are linked to their list of fields through a "next
88 field" in each variable that points to the next field in offset
90 Each variable for a structure field has
92 1. "size", that tells the size in bits of that field.
93 2. "fullsize, that tells the size in bits of the entire structure.
94 3. "offset", that tells the offset in bits from the beginning of the
95 structure to this field.
107 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
108 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
109 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
112 In order to solve the system of set constraints, the following is
115 1. Each constraint variable x has a solution set associated with it,
118 2. Constraints are separated into direct, copy, and complex.
119 Direct constraints are ADDRESSOF constraints that require no extra
120 processing, such as P = &Q
121 Copy constraints are those of the form P = Q.
122 Complex constraints are all the constraints involving dereferences
123 and offsets (including offsetted copies).
125 3. All direct constraints of the form P = &Q are processed, such
126 that Q is added to Sol(P)
128 4. All complex constraints for a given constraint variable are stored in a
129 linked list attached to that variable's node.
131 5. A directed graph is built out of the copy constraints. Each
132 constraint variable is a node in the graph, and an edge from
133 Q to P is added for each copy constraint of the form P = Q
135 6. The graph is then walked, and solution sets are
136 propagated along the copy edges, such that an edge from Q to P
137 causes Sol(P) <- Sol(P) union Sol(Q).
139 7. As we visit each node, all complex constraints associated with
140 that node are processed by adding appropriate copy edges to the graph, or the
141 appropriate variables to the solution set.
143 8. The process of walking the graph is iterated until no solution
146 Prior to walking the graph in steps 6 and 7, We perform static
147 cycle elimination on the constraint graph, as well
148 as off-line variable substitution.
150 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
151 on and turned into anything), but isn't. You can just see what offset
152 inside the pointed-to struct it's going to access.
154 TODO: Constant bounded arrays can be handled as if they were structs of the
155 same number of elements.
157 TODO: Modeling heap and incoming pointers becomes much better if we
158 add fields to them as we discover them, which we could do.
160 TODO: We could handle unions, but to be honest, it's probably not
161 worth the pain or slowdown. */
163 /* IPA-PTA optimizations possible.
165 When the indirect function called is ANYTHING we can add disambiguation
166 based on the function signatures (or simply the parameter count which
167 is the varinfo size). We also do not need to consider functions that
168 do not have their address taken.
170 The is_global_var bit which marks escape points is overly conservative
171 in IPA mode. Split it to is_escape_point and is_global_var - only
172 externally visible globals are escape points in IPA mode. This is
173 also needed to fix the pt_solution_includes_global predicate
174 (and thus ptr_deref_may_alias_global_p).
176 The way we introduce DECL_PT_UID to avoid fixing up all points-to
177 sets in the translation unit when we copy a DECL during inlining
178 pessimizes precision. The advantage is that the DECL_PT_UID keeps
179 compile-time and memory usage overhead low - the points-to sets
180 do not grow or get unshared as they would during a fixup phase.
181 An alternative solution is to delay IPA PTA until after all
182 inlining transformations have been applied.
184 The way we propagate clobber/use information isn't optimized.
185 It should use a new complex constraint that properly filters
186 out local variables of the callee (though that would make
187 the sets invalid after inlining). OTOH we might as well
188 admit defeat to WHOPR and simply do all the clobber/use analysis
189 and propagation after PTA finished but before we threw away
190 points-to information for memory variables. WHOPR and PTA
191 do not play along well anyway - the whole constraint solving
192 would need to be done in WPA phase and it will be very interesting
193 to apply the results to local SSA names during LTRANS phase.
195 We probably should compute a per-function unit-ESCAPE solution
196 propagating it simply like the clobber / uses solutions. The
197 solution can go alongside the non-IPA espaced solution and be
198 used to query which vars escape the unit through a function.
200 We never put function decls in points-to sets so we do not
201 keep the set of called functions for indirect calls.
203 And probably more. */
205 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
206 htab_t heapvar_for_stmt;
208 static bool use_field_sensitive = true;
209 static int in_ipa_mode = 0;
211 /* Used for predecessor bitmaps. */
212 static bitmap_obstack predbitmap_obstack;
214 /* Used for points-to sets. */
215 static bitmap_obstack pta_obstack;
217 /* Used for oldsolution members of variables. */
218 static bitmap_obstack oldpta_obstack;
220 /* Used for per-solver-iteration bitmaps. */
221 static bitmap_obstack iteration_obstack;
223 static unsigned int create_variable_info_for (tree, const char *);
224 typedef struct constraint_graph *constraint_graph_t;
225 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
228 typedef struct constraint *constraint_t;
230 DEF_VEC_P(constraint_t);
231 DEF_VEC_ALLOC_P(constraint_t,heap);
233 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
235 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
237 static struct constraint_stats
239 unsigned int total_vars;
240 unsigned int nonpointer_vars;
241 unsigned int unified_vars_static;
242 unsigned int unified_vars_dynamic;
243 unsigned int iterations;
244 unsigned int num_edges;
245 unsigned int num_implicit_edges;
246 unsigned int points_to_sets_created;
251 /* ID of this variable */
254 /* True if this is a variable created by the constraint analysis, such as
255 heap variables and constraints we had to break up. */
256 unsigned int is_artificial_var : 1;
258 /* True if this is a special variable whose solution set should not be
260 unsigned int is_special_var : 1;
262 /* True for variables whose size is not known or variable. */
263 unsigned int is_unknown_size_var : 1;
265 /* True for (sub-)fields that represent a whole variable. */
266 unsigned int is_full_var : 1;
268 /* True if this is a heap variable. */
269 unsigned int is_heap_var : 1;
271 /* True if this is a variable tracking a restrict pointer source. */
272 unsigned int is_restrict_var : 1;
274 /* True if this field may contain pointers. */
275 unsigned int may_have_pointers : 1;
277 /* True if this field has only restrict qualified pointers. */
278 unsigned int only_restrict_pointers : 1;
280 /* True if this represents a global variable. */
281 unsigned int is_global_var : 1;
283 /* True if this represents a IPA function info. */
284 unsigned int is_fn_info : 1;
286 /* A link to the variable for the next field in this structure. */
287 struct variable_info *next;
289 /* Offset of this variable, in bits, from the base variable */
290 unsigned HOST_WIDE_INT offset;
292 /* Size of the variable, in bits. */
293 unsigned HOST_WIDE_INT size;
295 /* Full size of the base variable, in bits. */
296 unsigned HOST_WIDE_INT fullsize;
298 /* Name of this variable */
301 /* Tree that this variable is associated with. */
304 /* Points-to set for this variable. */
307 /* Old points-to set for this variable. */
310 typedef struct variable_info *varinfo_t;
312 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
313 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
314 unsigned HOST_WIDE_INT);
315 static varinfo_t lookup_vi_for_tree (tree);
317 /* Pool of variable info structures. */
318 static alloc_pool variable_info_pool;
320 DEF_VEC_P(varinfo_t);
322 DEF_VEC_ALLOC_P(varinfo_t, heap);
324 /* Table of variable info structures for constraint variables.
325 Indexed directly by variable info id. */
326 static VEC(varinfo_t,heap) *varmap;
328 /* Return the varmap element N */
330 static inline varinfo_t
331 get_varinfo (unsigned int n)
333 return VEC_index (varinfo_t, varmap, n);
336 /* Static IDs for the special variables. */
337 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
338 escaped_id = 3, nonlocal_id = 4,
339 storedanything_id = 5, integer_id = 6 };
341 struct GTY(()) heapvar_map {
343 unsigned HOST_WIDE_INT offset;
347 heapvar_map_eq (const void *p1, const void *p2)
349 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
350 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
351 return (h1->map.base.from == h2->map.base.from
352 && h1->offset == h2->offset);
356 heapvar_map_hash (struct heapvar_map *h)
358 return iterative_hash_host_wide_int (h->offset,
359 htab_hash_pointer (h->map.base.from));
362 /* Lookup a heap var for FROM, and return it if we find one. */
365 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
367 struct heapvar_map *h, in;
368 in.map.base.from = from;
370 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
371 heapvar_map_hash (&in));
377 /* Insert a mapping FROM->TO in the heap var for statement
381 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
383 struct heapvar_map *h;
386 h = GGC_NEW (struct heapvar_map);
387 h->map.base.from = from;
389 h->map.hash = heapvar_map_hash (h);
391 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
392 gcc_assert (*loc == NULL);
393 *(struct heapvar_map **) loc = h;
396 /* Return a new variable info structure consisting for a variable
397 named NAME, and using constraint graph node NODE. Append it
398 to the vector of variable info structures. */
401 new_var_info (tree t, const char *name)
403 unsigned index = VEC_length (varinfo_t, varmap);
404 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
409 /* Vars without decl are artificial and do not have sub-variables. */
410 ret->is_artificial_var = (t == NULL_TREE);
411 ret->is_special_var = false;
412 ret->is_unknown_size_var = false;
413 ret->is_full_var = (t == NULL_TREE);
414 ret->is_heap_var = false;
415 ret->is_restrict_var = false;
416 ret->may_have_pointers = true;
417 ret->only_restrict_pointers = false;
418 ret->is_global_var = (t == NULL_TREE);
419 ret->is_fn_info = false;
421 ret->is_global_var = is_global_var (t);
422 ret->solution = BITMAP_ALLOC (&pta_obstack);
423 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
428 VEC_safe_push (varinfo_t, heap, varmap, ret);
434 /* A map mapping call statements to per-stmt variables for uses
435 and clobbers specific to the call. */
436 struct pointer_map_t *call_stmt_vars;
438 /* Lookup or create the variable for the call statement CALL. */
441 get_call_vi (gimple call)
446 slot_p = pointer_map_insert (call_stmt_vars, call);
448 return (varinfo_t) *slot_p;
450 vi = new_var_info (NULL_TREE, "CALLUSED");
454 vi->is_full_var = true;
456 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
460 vi2->is_full_var = true;
462 *slot_p = (void *) vi;
466 /* Lookup the variable for the call statement CALL representing
467 the uses. Returns NULL if there is nothing special about this call. */
470 lookup_call_use_vi (gimple call)
474 slot_p = pointer_map_contains (call_stmt_vars, call);
476 return (varinfo_t) *slot_p;
481 /* Lookup the variable for the call statement CALL representing
482 the clobbers. Returns NULL if there is nothing special about this call. */
485 lookup_call_clobber_vi (gimple call)
487 varinfo_t uses = lookup_call_use_vi (call);
494 /* Lookup or create the variable for the call statement CALL representing
498 get_call_use_vi (gimple call)
500 return get_call_vi (call);
503 /* Lookup or create the variable for the call statement CALL representing
506 static varinfo_t ATTRIBUTE_UNUSED
507 get_call_clobber_vi (gimple call)
509 return get_call_vi (call)->next;
513 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
515 /* An expression that appears in a constraint. */
517 struct constraint_expr
519 /* Constraint type. */
520 constraint_expr_type type;
522 /* Variable we are referring to in the constraint. */
525 /* Offset, in bits, of this constraint from the beginning of
526 variables it ends up referring to.
528 IOW, in a deref constraint, we would deref, get the result set,
529 then add OFFSET to each member. */
530 HOST_WIDE_INT offset;
533 /* Use 0x8000... as special unknown offset. */
534 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
536 typedef struct constraint_expr ce_s;
538 DEF_VEC_ALLOC_O(ce_s, heap);
539 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool);
540 static void get_constraint_for (tree, VEC(ce_s, heap) **);
541 static void do_deref (VEC (ce_s, heap) **);
543 /* Our set constraints are made up of two constraint expressions, one
546 As described in the introduction, our set constraints each represent an
547 operation between set valued variables.
551 struct constraint_expr lhs;
552 struct constraint_expr rhs;
555 /* List of constraints that we use to build the constraint graph from. */
557 static VEC(constraint_t,heap) *constraints;
558 static alloc_pool constraint_pool;
560 /* The constraint graph is represented as an array of bitmaps
561 containing successor nodes. */
563 struct constraint_graph
565 /* Size of this graph, which may be different than the number of
566 nodes in the variable map. */
569 /* Explicit successors of each node. */
572 /* Implicit predecessors of each node (Used for variable
574 bitmap *implicit_preds;
576 /* Explicit predecessors of each node (Used for variable substitution). */
579 /* Indirect cycle representatives, or -1 if the node has no indirect
581 int *indirect_cycles;
583 /* Representative node for a node. rep[a] == a unless the node has
587 /* Equivalence class representative for a label. This is used for
588 variable substitution. */
591 /* Pointer equivalence label for a node. All nodes with the same
592 pointer equivalence label can be unified together at some point
593 (either during constraint optimization or after the constraint
597 /* Pointer equivalence representative for a label. This is used to
598 handle nodes that are pointer equivalent but not location
599 equivalent. We can unite these once the addressof constraints
600 are transformed into initial points-to sets. */
603 /* Pointer equivalence label for each node, used during variable
605 unsigned int *pointer_label;
607 /* Location equivalence label for each node, used during location
608 equivalence finding. */
609 unsigned int *loc_label;
611 /* Pointed-by set for each node, used during location equivalence
612 finding. This is pointed-by rather than pointed-to, because it
613 is constructed using the predecessor graph. */
616 /* Points to sets for pointer equivalence. This is *not* the actual
617 points-to sets for nodes. */
620 /* Bitmap of nodes where the bit is set if the node is a direct
621 node. Used for variable substitution. */
622 sbitmap direct_nodes;
624 /* Bitmap of nodes where the bit is set if the node is address
625 taken. Used for variable substitution. */
626 bitmap address_taken;
628 /* Vector of complex constraints for each graph node. Complex
629 constraints are those involving dereferences or offsets that are
631 VEC(constraint_t,heap) **complex;
634 static constraint_graph_t graph;
636 /* During variable substitution and the offline version of indirect
637 cycle finding, we create nodes to represent dereferences and
638 address taken constraints. These represent where these start and
640 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
641 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
643 /* Return the representative node for NODE, if NODE has been unioned
645 This function performs path compression along the way to finding
646 the representative. */
649 find (unsigned int node)
651 gcc_assert (node < graph->size);
652 if (graph->rep[node] != node)
653 return graph->rep[node] = find (graph->rep[node]);
657 /* Union the TO and FROM nodes to the TO nodes.
658 Note that at some point in the future, we may want to do
659 union-by-rank, in which case we are going to have to return the
660 node we unified to. */
663 unite (unsigned int to, unsigned int from)
665 gcc_assert (to < graph->size && from < graph->size);
666 if (to != from && graph->rep[from] != to)
668 graph->rep[from] = to;
674 /* Create a new constraint consisting of LHS and RHS expressions. */
677 new_constraint (const struct constraint_expr lhs,
678 const struct constraint_expr rhs)
680 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
686 /* Print out constraint C to FILE. */
689 dump_constraint (FILE *file, constraint_t c)
691 if (c->lhs.type == ADDRESSOF)
693 else if (c->lhs.type == DEREF)
695 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
696 if (c->lhs.offset == UNKNOWN_OFFSET)
697 fprintf (file, " + UNKNOWN");
698 else if (c->lhs.offset != 0)
699 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
700 fprintf (file, " = ");
701 if (c->rhs.type == ADDRESSOF)
703 else if (c->rhs.type == DEREF)
705 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
706 if (c->rhs.offset == UNKNOWN_OFFSET)
707 fprintf (file, " + UNKNOWN");
708 else if (c->rhs.offset != 0)
709 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
710 fprintf (file, "\n");
714 void debug_constraint (constraint_t);
715 void debug_constraints (void);
716 void debug_constraint_graph (void);
717 void debug_solution_for_var (unsigned int);
718 void debug_sa_points_to_info (void);
720 /* Print out constraint C to stderr. */
723 debug_constraint (constraint_t c)
725 dump_constraint (stderr, c);
728 /* Print out all constraints to FILE */
731 dump_constraints (FILE *file, int from)
735 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
736 dump_constraint (file, c);
739 /* Print out all constraints to stderr. */
742 debug_constraints (void)
744 dump_constraints (stderr, 0);
747 /* Print out to FILE the edge in the constraint graph that is created by
748 constraint c. The edge may have a label, depending on the type of
749 constraint that it represents. If complex1, e.g: a = *b, then the label
750 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
751 complex with an offset, e.g: a = b + 8, then the label is "+".
752 Otherwise the edge has no label. */
755 dump_constraint_edge (FILE *file, constraint_t c)
757 if (c->rhs.type != ADDRESSOF)
759 const char *src = get_varinfo (c->rhs.var)->name;
760 const char *dst = get_varinfo (c->lhs.var)->name;
761 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
762 /* Due to preprocessing of constraints, instructions like *a = *b are
763 illegal; thus, we do not have to handle such cases. */
764 if (c->lhs.type == DEREF)
765 fprintf (file, " [ label=\"*=\" ] ;\n");
766 else if (c->rhs.type == DEREF)
767 fprintf (file, " [ label=\"=*\" ] ;\n");
770 /* We must check the case where the constraint is an offset.
771 In this case, it is treated as a complex constraint. */
772 if (c->rhs.offset != c->lhs.offset)
773 fprintf (file, " [ label=\"+\" ] ;\n");
775 fprintf (file, " ;\n");
780 /* Print the constraint graph in dot format. */
783 dump_constraint_graph (FILE *file)
785 unsigned int i=0, size;
788 /* Only print the graph if it has already been initialized: */
792 /* Print the constraints used to produce the constraint graph. The
793 constraints will be printed as comments in the dot file: */
794 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
795 dump_constraints (file, 0);
796 fprintf (file, "*/\n");
798 /* Prints the header of the dot file: */
799 fprintf (file, "\n\n// The constraint graph in dot format:\n");
800 fprintf (file, "strict digraph {\n");
801 fprintf (file, " node [\n shape = box\n ]\n");
802 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
803 fprintf (file, "\n // List of nodes in the constraint graph:\n");
805 /* The next lines print the nodes in the graph. In order to get the
806 number of nodes in the graph, we must choose the minimum between the
807 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
808 yet been initialized, then graph->size == 0, otherwise we must only
809 read nodes that have an entry in VEC (varinfo_t, varmap). */
810 size = VEC_length (varinfo_t, varmap);
811 size = size < graph->size ? size : graph->size;
812 for (i = 0; i < size; i++)
814 const char *name = get_varinfo (graph->rep[i])->name;
815 fprintf (file, " \"%s\" ;\n", name);
818 /* Go over the list of constraints printing the edges in the constraint
820 fprintf (file, "\n // The constraint edges:\n");
821 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
823 dump_constraint_edge (file, c);
825 /* Prints the tail of the dot file. By now, only the closing bracket. */
826 fprintf (file, "}\n\n\n");
829 /* Print out the constraint graph to stderr. */
832 debug_constraint_graph (void)
834 dump_constraint_graph (stderr);
839 The solver is a simple worklist solver, that works on the following
842 sbitmap changed_nodes = all zeroes;
844 For each node that is not already collapsed:
846 set bit in changed nodes
848 while (changed_count > 0)
850 compute topological ordering for constraint graph
852 find and collapse cycles in the constraint graph (updating
853 changed if necessary)
855 for each node (n) in the graph in topological order:
858 Process each complex constraint associated with the node,
859 updating changed if necessary.
861 For each outgoing edge from n, propagate the solution from n to
862 the destination of the edge, updating changed as necessary.
866 /* Return true if two constraint expressions A and B are equal. */
869 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
871 return a.type == b.type && a.var == b.var && a.offset == b.offset;
874 /* Return true if constraint expression A is less than constraint expression
875 B. This is just arbitrary, but consistent, in order to give them an
879 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
881 if (a.type == b.type)
884 return a.offset < b.offset;
886 return a.var < b.var;
889 return a.type < b.type;
892 /* Return true if constraint A is less than constraint B. This is just
893 arbitrary, but consistent, in order to give them an ordering. */
896 constraint_less (const constraint_t a, const constraint_t b)
898 if (constraint_expr_less (a->lhs, b->lhs))
900 else if (constraint_expr_less (b->lhs, a->lhs))
903 return constraint_expr_less (a->rhs, b->rhs);
906 /* Return true if two constraints A and B are equal. */
909 constraint_equal (struct constraint a, struct constraint b)
911 return constraint_expr_equal (a.lhs, b.lhs)
912 && constraint_expr_equal (a.rhs, b.rhs);
916 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
919 constraint_vec_find (VEC(constraint_t,heap) *vec,
920 struct constraint lookfor)
928 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
929 if (place >= VEC_length (constraint_t, vec))
931 found = VEC_index (constraint_t, vec, place);
932 if (!constraint_equal (*found, lookfor))
937 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
940 constraint_set_union (VEC(constraint_t,heap) **to,
941 VEC(constraint_t,heap) **from)
946 for (i = 0; VEC_iterate (constraint_t, *from, i, c); i++)
948 if (constraint_vec_find (*to, *c) == NULL)
950 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
952 VEC_safe_insert (constraint_t, heap, *to, place, c);
957 /* Expands the solution in SET to all sub-fields of variables included.
958 Union the expanded result into RESULT. */
961 solution_set_expand (bitmap result, bitmap set)
967 /* In a first pass record all variables we need to add all
968 sub-fields off. This avoids quadratic behavior. */
969 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
971 varinfo_t v = get_varinfo (j);
972 if (v->is_artificial_var
975 v = lookup_vi_for_tree (v->decl);
977 vars = BITMAP_ALLOC (NULL);
978 bitmap_set_bit (vars, v->id);
981 /* In the second pass now do the addition to the solution and
982 to speed up solving add it to the delta as well. */
985 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
987 varinfo_t v = get_varinfo (j);
988 for (; v != NULL; v = v->next)
989 bitmap_set_bit (result, v->id);
995 /* Take a solution set SET, add OFFSET to each member of the set, and
996 overwrite SET with the result when done. */
999 solution_set_add (bitmap set, HOST_WIDE_INT offset)
1001 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1005 /* If the offset is unknown we have to expand the solution to
1007 if (offset == UNKNOWN_OFFSET)
1009 solution_set_expand (set, set);
1013 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1015 varinfo_t vi = get_varinfo (i);
1017 /* If this is a variable with just one field just set its bit
1019 if (vi->is_artificial_var
1020 || vi->is_unknown_size_var
1022 bitmap_set_bit (result, i);
1025 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1027 /* If the offset makes the pointer point to before the
1028 variable use offset zero for the field lookup. */
1030 && fieldoffset > vi->offset)
1034 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1036 bitmap_set_bit (result, vi->id);
1037 /* If the result is not exactly at fieldoffset include the next
1038 field as well. See get_constraint_for_ptr_offset for more
1040 if (vi->offset != fieldoffset
1041 && vi->next != NULL)
1042 bitmap_set_bit (result, vi->next->id);
1046 bitmap_copy (set, result);
1047 BITMAP_FREE (result);
1050 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1054 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1057 return bitmap_ior_into (to, from);
1063 tmp = BITMAP_ALLOC (&iteration_obstack);
1064 bitmap_copy (tmp, from);
1065 solution_set_add (tmp, inc);
1066 res = bitmap_ior_into (to, tmp);
1072 /* Insert constraint C into the list of complex constraints for graph
1076 insert_into_complex (constraint_graph_t graph,
1077 unsigned int var, constraint_t c)
1079 VEC (constraint_t, heap) *complex = graph->complex[var];
1080 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1083 /* Only insert constraints that do not already exist. */
1084 if (place >= VEC_length (constraint_t, complex)
1085 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1086 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1090 /* Condense two variable nodes into a single variable node, by moving
1091 all associated info from SRC to TO. */
1094 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1100 gcc_assert (find (from) == to);
1102 /* Move all complex constraints from src node into to node */
1103 for (i = 0; VEC_iterate (constraint_t, graph->complex[from], i, c); i++)
1105 /* In complex constraints for node src, we may have either
1106 a = *src, and *src = a, or an offseted constraint which are
1107 always added to the rhs node's constraints. */
1109 if (c->rhs.type == DEREF)
1111 else if (c->lhs.type == DEREF)
1116 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1117 VEC_free (constraint_t, heap, graph->complex[from]);
1118 graph->complex[from] = NULL;
1122 /* Remove edges involving NODE from GRAPH. */
1125 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1127 if (graph->succs[node])
1128 BITMAP_FREE (graph->succs[node]);
1131 /* Merge GRAPH nodes FROM and TO into node TO. */
1134 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1137 if (graph->indirect_cycles[from] != -1)
1139 /* If we have indirect cycles with the from node, and we have
1140 none on the to node, the to node has indirect cycles from the
1141 from node now that they are unified.
1142 If indirect cycles exist on both, unify the nodes that they
1143 are in a cycle with, since we know they are in a cycle with
1145 if (graph->indirect_cycles[to] == -1)
1146 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1149 /* Merge all the successor edges. */
1150 if (graph->succs[from])
1152 if (!graph->succs[to])
1153 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1154 bitmap_ior_into (graph->succs[to],
1155 graph->succs[from]);
1158 clear_edges_for_node (graph, from);
1162 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1163 it doesn't exist in the graph already. */
1166 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1172 if (!graph->implicit_preds[to])
1173 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1175 if (bitmap_set_bit (graph->implicit_preds[to], from))
1176 stats.num_implicit_edges++;
1179 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1180 it doesn't exist in the graph already.
1181 Return false if the edge already existed, true otherwise. */
1184 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1187 if (!graph->preds[to])
1188 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1189 bitmap_set_bit (graph->preds[to], from);
1192 /* Add a graph edge to GRAPH, going from FROM to TO if
1193 it doesn't exist in the graph already.
1194 Return false if the edge already existed, true otherwise. */
1197 add_graph_edge (constraint_graph_t graph, unsigned int to,
1208 if (!graph->succs[from])
1209 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1210 if (bitmap_set_bit (graph->succs[from], to))
1213 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1221 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1224 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1227 return (graph->succs[dest]
1228 && bitmap_bit_p (graph->succs[dest], src));
1231 /* Initialize the constraint graph structure to contain SIZE nodes. */
1234 init_graph (unsigned int size)
1238 graph = XCNEW (struct constraint_graph);
1240 graph->succs = XCNEWVEC (bitmap, graph->size);
1241 graph->indirect_cycles = XNEWVEC (int, graph->size);
1242 graph->rep = XNEWVEC (unsigned int, graph->size);
1243 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1244 graph->pe = XCNEWVEC (unsigned int, graph->size);
1245 graph->pe_rep = XNEWVEC (int, graph->size);
1247 for (j = 0; j < graph->size; j++)
1250 graph->pe_rep[j] = -1;
1251 graph->indirect_cycles[j] = -1;
1255 /* Build the constraint graph, adding only predecessor edges right now. */
1258 build_pred_graph (void)
1264 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1265 graph->preds = XCNEWVEC (bitmap, graph->size);
1266 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1267 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1268 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1269 graph->points_to = XCNEWVEC (bitmap, graph->size);
1270 graph->eq_rep = XNEWVEC (int, graph->size);
1271 graph->direct_nodes = sbitmap_alloc (graph->size);
1272 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1273 sbitmap_zero (graph->direct_nodes);
1275 for (j = 0; j < FIRST_REF_NODE; j++)
1277 if (!get_varinfo (j)->is_special_var)
1278 SET_BIT (graph->direct_nodes, j);
1281 for (j = 0; j < graph->size; j++)
1282 graph->eq_rep[j] = -1;
1284 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1285 graph->indirect_cycles[j] = -1;
1287 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1289 struct constraint_expr lhs = c->lhs;
1290 struct constraint_expr rhs = c->rhs;
1291 unsigned int lhsvar = lhs.var;
1292 unsigned int rhsvar = rhs.var;
1294 if (lhs.type == DEREF)
1297 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1298 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1300 else if (rhs.type == DEREF)
1303 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1304 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1306 RESET_BIT (graph->direct_nodes, lhsvar);
1308 else if (rhs.type == ADDRESSOF)
1313 if (graph->points_to[lhsvar] == NULL)
1314 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1315 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1317 if (graph->pointed_by[rhsvar] == NULL)
1318 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1319 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1321 /* Implicitly, *x = y */
1322 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1324 /* All related variables are no longer direct nodes. */
1325 RESET_BIT (graph->direct_nodes, rhsvar);
1326 v = get_varinfo (rhsvar);
1327 if (!v->is_full_var)
1329 v = lookup_vi_for_tree (v->decl);
1332 RESET_BIT (graph->direct_nodes, v->id);
1337 bitmap_set_bit (graph->address_taken, rhsvar);
1339 else if (lhsvar > anything_id
1340 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1343 add_pred_graph_edge (graph, lhsvar, rhsvar);
1344 /* Implicitly, *x = *y */
1345 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1346 FIRST_REF_NODE + rhsvar);
1348 else if (lhs.offset != 0 || rhs.offset != 0)
1350 if (rhs.offset != 0)
1351 RESET_BIT (graph->direct_nodes, lhs.var);
1352 else if (lhs.offset != 0)
1353 RESET_BIT (graph->direct_nodes, rhs.var);
1358 /* Build the constraint graph, adding successor edges. */
1361 build_succ_graph (void)
1366 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
1368 struct constraint_expr lhs;
1369 struct constraint_expr rhs;
1370 unsigned int lhsvar;
1371 unsigned int rhsvar;
1378 lhsvar = find (lhs.var);
1379 rhsvar = find (rhs.var);
1381 if (lhs.type == DEREF)
1383 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1384 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1386 else if (rhs.type == DEREF)
1388 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1389 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1391 else if (rhs.type == ADDRESSOF)
1394 gcc_assert (find (rhs.var) == rhs.var);
1395 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1397 else if (lhsvar > anything_id
1398 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1400 add_graph_edge (graph, lhsvar, rhsvar);
1404 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1405 receive pointers. */
1406 t = find (storedanything_id);
1407 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1409 if (!TEST_BIT (graph->direct_nodes, i)
1410 && get_varinfo (i)->may_have_pointers)
1411 add_graph_edge (graph, find (i), t);
1414 /* Everything stored to ANYTHING also potentially escapes. */
1415 add_graph_edge (graph, find (escaped_id), t);
1419 /* Changed variables on the last iteration. */
1420 static unsigned int changed_count;
1421 static sbitmap changed;
1423 /* Strongly Connected Component visitation info. */
1430 unsigned int *node_mapping;
1432 VEC(unsigned,heap) *scc_stack;
1436 /* Recursive routine to find strongly connected components in GRAPH.
1437 SI is the SCC info to store the information in, and N is the id of current
1438 graph node we are processing.
1440 This is Tarjan's strongly connected component finding algorithm, as
1441 modified by Nuutila to keep only non-root nodes on the stack.
1442 The algorithm can be found in "On finding the strongly connected
1443 connected components in a directed graph" by Esko Nuutila and Eljas
1444 Soisalon-Soininen, in Information Processing Letters volume 49,
1445 number 1, pages 9-14. */
1448 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1452 unsigned int my_dfs;
1454 SET_BIT (si->visited, n);
1455 si->dfs[n] = si->current_index ++;
1456 my_dfs = si->dfs[n];
1458 /* Visit all the successors. */
1459 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1463 if (i > LAST_REF_NODE)
1467 if (TEST_BIT (si->deleted, w))
1470 if (!TEST_BIT (si->visited, w))
1471 scc_visit (graph, si, w);
1473 unsigned int t = find (w);
1474 unsigned int nnode = find (n);
1475 gcc_assert (nnode == n);
1477 if (si->dfs[t] < si->dfs[nnode])
1478 si->dfs[n] = si->dfs[t];
1482 /* See if any components have been identified. */
1483 if (si->dfs[n] == my_dfs)
1485 if (VEC_length (unsigned, si->scc_stack) > 0
1486 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1488 bitmap scc = BITMAP_ALLOC (NULL);
1489 unsigned int lowest_node;
1492 bitmap_set_bit (scc, n);
1494 while (VEC_length (unsigned, si->scc_stack) != 0
1495 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1497 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1499 bitmap_set_bit (scc, w);
1502 lowest_node = bitmap_first_set_bit (scc);
1503 gcc_assert (lowest_node < FIRST_REF_NODE);
1505 /* Collapse the SCC nodes into a single node, and mark the
1507 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1509 if (i < FIRST_REF_NODE)
1511 if (unite (lowest_node, i))
1512 unify_nodes (graph, lowest_node, i, false);
1516 unite (lowest_node, i);
1517 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1521 SET_BIT (si->deleted, n);
1524 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1527 /* Unify node FROM into node TO, updating the changed count if
1528 necessary when UPDATE_CHANGED is true. */
1531 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1532 bool update_changed)
1535 gcc_assert (to != from && find (to) == to);
1536 if (dump_file && (dump_flags & TDF_DETAILS))
1537 fprintf (dump_file, "Unifying %s to %s\n",
1538 get_varinfo (from)->name,
1539 get_varinfo (to)->name);
1542 stats.unified_vars_dynamic++;
1544 stats.unified_vars_static++;
1546 merge_graph_nodes (graph, to, from);
1547 merge_node_constraints (graph, to, from);
1549 /* Mark TO as changed if FROM was changed. If TO was already marked
1550 as changed, decrease the changed count. */
1552 if (update_changed && TEST_BIT (changed, from))
1554 RESET_BIT (changed, from);
1555 if (!TEST_BIT (changed, to))
1556 SET_BIT (changed, to);
1559 gcc_assert (changed_count > 0);
1563 if (get_varinfo (from)->solution)
1565 /* If the solution changes because of the merging, we need to mark
1566 the variable as changed. */
1567 if (bitmap_ior_into (get_varinfo (to)->solution,
1568 get_varinfo (from)->solution))
1570 if (update_changed && !TEST_BIT (changed, to))
1572 SET_BIT (changed, to);
1577 BITMAP_FREE (get_varinfo (from)->solution);
1578 BITMAP_FREE (get_varinfo (from)->oldsolution);
1580 if (stats.iterations > 0)
1582 BITMAP_FREE (get_varinfo (to)->oldsolution);
1583 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1586 if (valid_graph_edge (graph, to, to))
1588 if (graph->succs[to])
1589 bitmap_clear_bit (graph->succs[to], to);
1593 /* Information needed to compute the topological ordering of a graph. */
1597 /* sbitmap of visited nodes. */
1599 /* Array that stores the topological order of the graph, *in
1601 VEC(unsigned,heap) *topo_order;
1605 /* Initialize and return a topological info structure. */
1607 static struct topo_info *
1608 init_topo_info (void)
1610 size_t size = graph->size;
1611 struct topo_info *ti = XNEW (struct topo_info);
1612 ti->visited = sbitmap_alloc (size);
1613 sbitmap_zero (ti->visited);
1614 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1619 /* Free the topological sort info pointed to by TI. */
1622 free_topo_info (struct topo_info *ti)
1624 sbitmap_free (ti->visited);
1625 VEC_free (unsigned, heap, ti->topo_order);
1629 /* Visit the graph in topological order, and store the order in the
1630 topo_info structure. */
1633 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1639 SET_BIT (ti->visited, n);
1641 if (graph->succs[n])
1642 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1644 if (!TEST_BIT (ti->visited, j))
1645 topo_visit (graph, ti, j);
1648 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1651 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1652 starting solution for y. */
1655 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1658 unsigned int lhs = c->lhs.var;
1660 bitmap sol = get_varinfo (lhs)->solution;
1663 HOST_WIDE_INT roffset = c->rhs.offset;
1665 /* Our IL does not allow this. */
1666 gcc_assert (c->lhs.offset == 0);
1668 /* If the solution of Y contains anything it is good enough to transfer
1670 if (bitmap_bit_p (delta, anything_id))
1672 flag |= bitmap_set_bit (sol, anything_id);
1676 /* If we do not know at with offset the rhs is dereferenced compute
1677 the reachability set of DELTA, conservatively assuming it is
1678 dereferenced at all valid offsets. */
1679 if (roffset == UNKNOWN_OFFSET)
1681 solution_set_expand (delta, delta);
1682 /* No further offset processing is necessary. */
1686 /* For each variable j in delta (Sol(y)), add
1687 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1688 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1690 varinfo_t v = get_varinfo (j);
1691 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1695 fieldoffset = v->offset;
1696 else if (roffset != 0)
1697 v = first_vi_for_offset (v, fieldoffset);
1698 /* If the access is outside of the variable we can ignore it. */
1706 /* Adding edges from the special vars is pointless.
1707 They don't have sets that can change. */
1708 if (get_varinfo (t)->is_special_var)
1709 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1710 /* Merging the solution from ESCAPED needlessly increases
1711 the set. Use ESCAPED as representative instead. */
1712 else if (v->id == escaped_id)
1713 flag |= bitmap_set_bit (sol, escaped_id);
1714 else if (v->may_have_pointers
1715 && add_graph_edge (graph, lhs, t))
1716 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1718 /* If the variable is not exactly at the requested offset
1719 we have to include the next one. */
1720 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1725 fieldoffset = v->offset;
1731 /* If the LHS solution changed, mark the var as changed. */
1734 get_varinfo (lhs)->solution = sol;
1735 if (!TEST_BIT (changed, lhs))
1737 SET_BIT (changed, lhs);
1743 /* Process a constraint C that represents *(x + off) = y using DELTA
1744 as the starting solution for x. */
1747 do_ds_constraint (constraint_t c, bitmap delta)
1749 unsigned int rhs = c->rhs.var;
1750 bitmap sol = get_varinfo (rhs)->solution;
1753 HOST_WIDE_INT loff = c->lhs.offset;
1754 bool escaped_p = false;
1756 /* Our IL does not allow this. */
1757 gcc_assert (c->rhs.offset == 0);
1759 /* If the solution of y contains ANYTHING simply use the ANYTHING
1760 solution. This avoids needlessly increasing the points-to sets. */
1761 if (bitmap_bit_p (sol, anything_id))
1762 sol = get_varinfo (find (anything_id))->solution;
1764 /* If the solution for x contains ANYTHING we have to merge the
1765 solution of y into all pointer variables which we do via
1767 if (bitmap_bit_p (delta, anything_id))
1769 unsigned t = find (storedanything_id);
1770 if (add_graph_edge (graph, t, rhs))
1772 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1774 if (!TEST_BIT (changed, t))
1776 SET_BIT (changed, t);
1784 /* If we do not know at with offset the rhs is dereferenced compute
1785 the reachability set of DELTA, conservatively assuming it is
1786 dereferenced at all valid offsets. */
1787 if (loff == UNKNOWN_OFFSET)
1789 solution_set_expand (delta, delta);
1793 /* For each member j of delta (Sol(x)), add an edge from y to j and
1794 union Sol(y) into Sol(j) */
1795 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1797 varinfo_t v = get_varinfo (j);
1799 HOST_WIDE_INT fieldoffset = v->offset + loff;
1802 fieldoffset = v->offset;
1804 v = first_vi_for_offset (v, fieldoffset);
1805 /* If the access is outside of the variable we can ignore it. */
1811 if (v->may_have_pointers)
1813 /* If v is a global variable then this is an escape point. */
1814 if (v->is_global_var
1817 t = find (escaped_id);
1818 if (add_graph_edge (graph, t, rhs)
1819 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1820 && !TEST_BIT (changed, t))
1822 SET_BIT (changed, t);
1825 /* Enough to let rhs escape once. */
1829 if (v->is_special_var)
1833 if (add_graph_edge (graph, t, rhs)
1834 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1835 && !TEST_BIT (changed, t))
1837 SET_BIT (changed, t);
1842 /* If the variable is not exactly at the requested offset
1843 we have to include the next one. */
1844 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1849 fieldoffset = v->offset;
1855 /* Handle a non-simple (simple meaning requires no iteration),
1856 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1859 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1861 if (c->lhs.type == DEREF)
1863 if (c->rhs.type == ADDRESSOF)
1870 do_ds_constraint (c, delta);
1873 else if (c->rhs.type == DEREF)
1876 if (!(get_varinfo (c->lhs.var)->is_special_var))
1877 do_sd_constraint (graph, c, delta);
1885 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1886 solution = get_varinfo (c->rhs.var)->solution;
1887 tmp = get_varinfo (c->lhs.var)->solution;
1889 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1893 get_varinfo (c->lhs.var)->solution = tmp;
1894 if (!TEST_BIT (changed, c->lhs.var))
1896 SET_BIT (changed, c->lhs.var);
1903 /* Initialize and return a new SCC info structure. */
1905 static struct scc_info *
1906 init_scc_info (size_t size)
1908 struct scc_info *si = XNEW (struct scc_info);
1911 si->current_index = 0;
1912 si->visited = sbitmap_alloc (size);
1913 sbitmap_zero (si->visited);
1914 si->deleted = sbitmap_alloc (size);
1915 sbitmap_zero (si->deleted);
1916 si->node_mapping = XNEWVEC (unsigned int, size);
1917 si->dfs = XCNEWVEC (unsigned int, size);
1919 for (i = 0; i < size; i++)
1920 si->node_mapping[i] = i;
1922 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1926 /* Free an SCC info structure pointed to by SI */
1929 free_scc_info (struct scc_info *si)
1931 sbitmap_free (si->visited);
1932 sbitmap_free (si->deleted);
1933 free (si->node_mapping);
1935 VEC_free (unsigned, heap, si->scc_stack);
1940 /* Find indirect cycles in GRAPH that occur, using strongly connected
1941 components, and note them in the indirect cycles map.
1943 This technique comes from Ben Hardekopf and Calvin Lin,
1944 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1945 Lines of Code", submitted to PLDI 2007. */
1948 find_indirect_cycles (constraint_graph_t graph)
1951 unsigned int size = graph->size;
1952 struct scc_info *si = init_scc_info (size);
1954 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1955 if (!TEST_BIT (si->visited, i) && find (i) == i)
1956 scc_visit (graph, si, i);
1961 /* Compute a topological ordering for GRAPH, and store the result in the
1962 topo_info structure TI. */
1965 compute_topo_order (constraint_graph_t graph,
1966 struct topo_info *ti)
1969 unsigned int size = graph->size;
1971 for (i = 0; i != size; ++i)
1972 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1973 topo_visit (graph, ti, i);
1976 /* Structure used to for hash value numbering of pointer equivalence
1979 typedef struct equiv_class_label
1982 unsigned int equivalence_class;
1984 } *equiv_class_label_t;
1985 typedef const struct equiv_class_label *const_equiv_class_label_t;
1987 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1989 static htab_t pointer_equiv_class_table;
1991 /* A hashtable for mapping a bitmap of labels->location equivalence
1993 static htab_t location_equiv_class_table;
1995 /* Hash function for a equiv_class_label_t */
1998 equiv_class_label_hash (const void *p)
2000 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
2001 return ecl->hashcode;
2004 /* Equality function for two equiv_class_label_t's. */
2007 equiv_class_label_eq (const void *p1, const void *p2)
2009 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2010 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2011 return (eql1->hashcode == eql2->hashcode
2012 && bitmap_equal_p (eql1->labels, eql2->labels));
2015 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2019 equiv_class_lookup (htab_t table, bitmap labels)
2022 struct equiv_class_label ecl;
2024 ecl.labels = labels;
2025 ecl.hashcode = bitmap_hash (labels);
2027 slot = htab_find_slot_with_hash (table, &ecl,
2028 ecl.hashcode, NO_INSERT);
2032 return ((equiv_class_label_t) *slot)->equivalence_class;
2036 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2040 equiv_class_add (htab_t table, unsigned int equivalence_class,
2044 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2046 ecl->labels = labels;
2047 ecl->equivalence_class = equivalence_class;
2048 ecl->hashcode = bitmap_hash (labels);
2050 slot = htab_find_slot_with_hash (table, ecl,
2051 ecl->hashcode, INSERT);
2052 gcc_assert (!*slot);
2053 *slot = (void *) ecl;
2056 /* Perform offline variable substitution.
2058 This is a worst case quadratic time way of identifying variables
2059 that must have equivalent points-to sets, including those caused by
2060 static cycles, and single entry subgraphs, in the constraint graph.
2062 The technique is described in "Exploiting Pointer and Location
2063 Equivalence to Optimize Pointer Analysis. In the 14th International
2064 Static Analysis Symposium (SAS), August 2007." It is known as the
2065 "HU" algorithm, and is equivalent to value numbering the collapsed
2066 constraint graph including evaluating unions.
2068 The general method of finding equivalence classes is as follows:
2069 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2070 Initialize all non-REF nodes to be direct nodes.
2071 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2073 For each constraint containing the dereference, we also do the same
2076 We then compute SCC's in the graph and unify nodes in the same SCC,
2079 For each non-collapsed node x:
2080 Visit all unvisited explicit incoming edges.
2081 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2083 Lookup the equivalence class for pts(x).
2084 If we found one, equivalence_class(x) = found class.
2085 Otherwise, equivalence_class(x) = new class, and new_class is
2086 added to the lookup table.
2088 All direct nodes with the same equivalence class can be replaced
2089 with a single representative node.
2090 All unlabeled nodes (label == 0) are not pointers and all edges
2091 involving them can be eliminated.
2092 We perform these optimizations during rewrite_constraints
2094 In addition to pointer equivalence class finding, we also perform
2095 location equivalence class finding. This is the set of variables
2096 that always appear together in points-to sets. We use this to
2097 compress the size of the points-to sets. */
2099 /* Current maximum pointer equivalence class id. */
2100 static int pointer_equiv_class;
2102 /* Current maximum location equivalence class id. */
2103 static int location_equiv_class;
2105 /* Recursive routine to find strongly connected components in GRAPH,
2106 and label it's nodes with DFS numbers. */
2109 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2113 unsigned int my_dfs;
2115 gcc_assert (si->node_mapping[n] == n);
2116 SET_BIT (si->visited, n);
2117 si->dfs[n] = si->current_index ++;
2118 my_dfs = si->dfs[n];
2120 /* Visit all the successors. */
2121 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2123 unsigned int w = si->node_mapping[i];
2125 if (TEST_BIT (si->deleted, w))
2128 if (!TEST_BIT (si->visited, w))
2129 condense_visit (graph, si, w);
2131 unsigned int t = si->node_mapping[w];
2132 unsigned int nnode = si->node_mapping[n];
2133 gcc_assert (nnode == n);
2135 if (si->dfs[t] < si->dfs[nnode])
2136 si->dfs[n] = si->dfs[t];
2140 /* Visit all the implicit predecessors. */
2141 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2143 unsigned int w = si->node_mapping[i];
2145 if (TEST_BIT (si->deleted, w))
2148 if (!TEST_BIT (si->visited, w))
2149 condense_visit (graph, si, w);
2151 unsigned int t = si->node_mapping[w];
2152 unsigned int nnode = si->node_mapping[n];
2153 gcc_assert (nnode == n);
2155 if (si->dfs[t] < si->dfs[nnode])
2156 si->dfs[n] = si->dfs[t];
2160 /* See if any components have been identified. */
2161 if (si->dfs[n] == my_dfs)
2163 while (VEC_length (unsigned, si->scc_stack) != 0
2164 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2166 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2167 si->node_mapping[w] = n;
2169 if (!TEST_BIT (graph->direct_nodes, w))
2170 RESET_BIT (graph->direct_nodes, n);
2172 /* Unify our nodes. */
2173 if (graph->preds[w])
2175 if (!graph->preds[n])
2176 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2177 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2179 if (graph->implicit_preds[w])
2181 if (!graph->implicit_preds[n])
2182 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2183 bitmap_ior_into (graph->implicit_preds[n],
2184 graph->implicit_preds[w]);
2186 if (graph->points_to[w])
2188 if (!graph->points_to[n])
2189 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2190 bitmap_ior_into (graph->points_to[n],
2191 graph->points_to[w]);
2194 SET_BIT (si->deleted, n);
2197 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2200 /* Label pointer equivalences. */
2203 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2207 SET_BIT (si->visited, n);
2209 if (!graph->points_to[n])
2210 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2212 /* Label and union our incoming edges's points to sets. */
2213 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2215 unsigned int w = si->node_mapping[i];
2216 if (!TEST_BIT (si->visited, w))
2217 label_visit (graph, si, w);
2219 /* Skip unused edges */
2220 if (w == n || graph->pointer_label[w] == 0)
2223 if (graph->points_to[w])
2224 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2226 /* Indirect nodes get fresh variables. */
2227 if (!TEST_BIT (graph->direct_nodes, n))
2228 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2230 if (!bitmap_empty_p (graph->points_to[n]))
2232 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2233 graph->points_to[n]);
2236 label = pointer_equiv_class++;
2237 equiv_class_add (pointer_equiv_class_table,
2238 label, graph->points_to[n]);
2240 graph->pointer_label[n] = label;
2244 /* Perform offline variable substitution, discovering equivalence
2245 classes, and eliminating non-pointer variables. */
2247 static struct scc_info *
2248 perform_var_substitution (constraint_graph_t graph)
2251 unsigned int size = graph->size;
2252 struct scc_info *si = init_scc_info (size);
2254 bitmap_obstack_initialize (&iteration_obstack);
2255 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2256 equiv_class_label_eq, free);
2257 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2258 equiv_class_label_eq, free);
2259 pointer_equiv_class = 1;
2260 location_equiv_class = 1;
2262 /* Condense the nodes, which means to find SCC's, count incoming
2263 predecessors, and unite nodes in SCC's. */
2264 for (i = 0; i < FIRST_REF_NODE; i++)
2265 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2266 condense_visit (graph, si, si->node_mapping[i]);
2268 sbitmap_zero (si->visited);
2269 /* Actually the label the nodes for pointer equivalences */
2270 for (i = 0; i < FIRST_REF_NODE; i++)
2271 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2272 label_visit (graph, si, si->node_mapping[i]);
2274 /* Calculate location equivalence labels. */
2275 for (i = 0; i < FIRST_REF_NODE; i++)
2282 if (!graph->pointed_by[i])
2284 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2286 /* Translate the pointed-by mapping for pointer equivalence
2288 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2290 bitmap_set_bit (pointed_by,
2291 graph->pointer_label[si->node_mapping[j]]);
2293 /* The original pointed_by is now dead. */
2294 BITMAP_FREE (graph->pointed_by[i]);
2296 /* Look up the location equivalence label if one exists, or make
2298 label = equiv_class_lookup (location_equiv_class_table,
2302 label = location_equiv_class++;
2303 equiv_class_add (location_equiv_class_table,
2308 if (dump_file && (dump_flags & TDF_DETAILS))
2309 fprintf (dump_file, "Found location equivalence for node %s\n",
2310 get_varinfo (i)->name);
2311 BITMAP_FREE (pointed_by);
2313 graph->loc_label[i] = label;
2317 if (dump_file && (dump_flags & TDF_DETAILS))
2318 for (i = 0; i < FIRST_REF_NODE; i++)
2320 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2322 "Equivalence classes for %s node id %d:%s are pointer: %d"
2324 direct_node ? "Direct node" : "Indirect node", i,
2325 get_varinfo (i)->name,
2326 graph->pointer_label[si->node_mapping[i]],
2327 graph->loc_label[si->node_mapping[i]]);
2330 /* Quickly eliminate our non-pointer variables. */
2332 for (i = 0; i < FIRST_REF_NODE; i++)
2334 unsigned int node = si->node_mapping[i];
2336 if (graph->pointer_label[node] == 0)
2338 if (dump_file && (dump_flags & TDF_DETAILS))
2340 "%s is a non-pointer variable, eliminating edges.\n",
2341 get_varinfo (node)->name);
2342 stats.nonpointer_vars++;
2343 clear_edges_for_node (graph, node);
2350 /* Free information that was only necessary for variable
2354 free_var_substitution_info (struct scc_info *si)
2357 free (graph->pointer_label);
2358 free (graph->loc_label);
2359 free (graph->pointed_by);
2360 free (graph->points_to);
2361 free (graph->eq_rep);
2362 sbitmap_free (graph->direct_nodes);
2363 htab_delete (pointer_equiv_class_table);
2364 htab_delete (location_equiv_class_table);
2365 bitmap_obstack_release (&iteration_obstack);
2368 /* Return an existing node that is equivalent to NODE, which has
2369 equivalence class LABEL, if one exists. Return NODE otherwise. */
2372 find_equivalent_node (constraint_graph_t graph,
2373 unsigned int node, unsigned int label)
2375 /* If the address version of this variable is unused, we can
2376 substitute it for anything else with the same label.
2377 Otherwise, we know the pointers are equivalent, but not the
2378 locations, and we can unite them later. */
2380 if (!bitmap_bit_p (graph->address_taken, node))
2382 gcc_assert (label < graph->size);
2384 if (graph->eq_rep[label] != -1)
2386 /* Unify the two variables since we know they are equivalent. */
2387 if (unite (graph->eq_rep[label], node))
2388 unify_nodes (graph, graph->eq_rep[label], node, false);
2389 return graph->eq_rep[label];
2393 graph->eq_rep[label] = node;
2394 graph->pe_rep[label] = node;
2399 gcc_assert (label < graph->size);
2400 graph->pe[node] = label;
2401 if (graph->pe_rep[label] == -1)
2402 graph->pe_rep[label] = node;
2408 /* Unite pointer equivalent but not location equivalent nodes in
2409 GRAPH. This may only be performed once variable substitution is
2413 unite_pointer_equivalences (constraint_graph_t graph)
2417 /* Go through the pointer equivalences and unite them to their
2418 representative, if they aren't already. */
2419 for (i = 0; i < FIRST_REF_NODE; i++)
2421 unsigned int label = graph->pe[i];
2424 int label_rep = graph->pe_rep[label];
2426 if (label_rep == -1)
2429 label_rep = find (label_rep);
2430 if (label_rep >= 0 && unite (label_rep, find (i)))
2431 unify_nodes (graph, label_rep, i, false);
2436 /* Move complex constraints to the GRAPH nodes they belong to. */
2439 move_complex_constraints (constraint_graph_t graph)
2444 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2448 struct constraint_expr lhs = c->lhs;
2449 struct constraint_expr rhs = c->rhs;
2451 if (lhs.type == DEREF)
2453 insert_into_complex (graph, lhs.var, c);
2455 else if (rhs.type == DEREF)
2457 if (!(get_varinfo (lhs.var)->is_special_var))
2458 insert_into_complex (graph, rhs.var, c);
2460 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2461 && (lhs.offset != 0 || rhs.offset != 0))
2463 insert_into_complex (graph, rhs.var, c);
2470 /* Optimize and rewrite complex constraints while performing
2471 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2472 result of perform_variable_substitution. */
2475 rewrite_constraints (constraint_graph_t graph,
2476 struct scc_info *si)
2482 for (j = 0; j < graph->size; j++)
2483 gcc_assert (find (j) == j);
2485 for (i = 0; VEC_iterate (constraint_t, constraints, i, c); i++)
2487 struct constraint_expr lhs = c->lhs;
2488 struct constraint_expr rhs = c->rhs;
2489 unsigned int lhsvar = find (lhs.var);
2490 unsigned int rhsvar = find (rhs.var);
2491 unsigned int lhsnode, rhsnode;
2492 unsigned int lhslabel, rhslabel;
2494 lhsnode = si->node_mapping[lhsvar];
2495 rhsnode = si->node_mapping[rhsvar];
2496 lhslabel = graph->pointer_label[lhsnode];
2497 rhslabel = graph->pointer_label[rhsnode];
2499 /* See if it is really a non-pointer variable, and if so, ignore
2503 if (dump_file && (dump_flags & TDF_DETAILS))
2506 fprintf (dump_file, "%s is a non-pointer variable,"
2507 "ignoring constraint:",
2508 get_varinfo (lhs.var)->name);
2509 dump_constraint (dump_file, c);
2511 VEC_replace (constraint_t, constraints, i, NULL);
2517 if (dump_file && (dump_flags & TDF_DETAILS))
2520 fprintf (dump_file, "%s is a non-pointer variable,"
2521 "ignoring constraint:",
2522 get_varinfo (rhs.var)->name);
2523 dump_constraint (dump_file, c);
2525 VEC_replace (constraint_t, constraints, i, NULL);
2529 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2530 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2531 c->lhs.var = lhsvar;
2532 c->rhs.var = rhsvar;
2537 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2538 part of an SCC, false otherwise. */
2541 eliminate_indirect_cycles (unsigned int node)
2543 if (graph->indirect_cycles[node] != -1
2544 && !bitmap_empty_p (get_varinfo (node)->solution))
2547 VEC(unsigned,heap) *queue = NULL;
2549 unsigned int to = find (graph->indirect_cycles[node]);
2552 /* We can't touch the solution set and call unify_nodes
2553 at the same time, because unify_nodes is going to do
2554 bitmap unions into it. */
2556 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2558 if (find (i) == i && i != to)
2561 VEC_safe_push (unsigned, heap, queue, i);
2566 VEC_iterate (unsigned, queue, queuepos, i);
2569 unify_nodes (graph, to, i, true);
2571 VEC_free (unsigned, heap, queue);
2577 /* Solve the constraint graph GRAPH using our worklist solver.
2578 This is based on the PW* family of solvers from the "Efficient Field
2579 Sensitive Pointer Analysis for C" paper.
2580 It works by iterating over all the graph nodes, processing the complex
2581 constraints and propagating the copy constraints, until everything stops
2582 changed. This corresponds to steps 6-8 in the solving list given above. */
2585 solve_graph (constraint_graph_t graph)
2587 unsigned int size = graph->size;
2592 changed = sbitmap_alloc (size);
2593 sbitmap_zero (changed);
2595 /* Mark all initial non-collapsed nodes as changed. */
2596 for (i = 0; i < size; i++)
2598 varinfo_t ivi = get_varinfo (i);
2599 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2600 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2601 || VEC_length (constraint_t, graph->complex[i]) > 0))
2603 SET_BIT (changed, i);
2608 /* Allocate a bitmap to be used to store the changed bits. */
2609 pts = BITMAP_ALLOC (&pta_obstack);
2611 while (changed_count > 0)
2614 struct topo_info *ti = init_topo_info ();
2617 bitmap_obstack_initialize (&iteration_obstack);
2619 compute_topo_order (graph, ti);
2621 while (VEC_length (unsigned, ti->topo_order) != 0)
2624 i = VEC_pop (unsigned, ti->topo_order);
2626 /* If this variable is not a representative, skip it. */
2630 /* In certain indirect cycle cases, we may merge this
2631 variable to another. */
2632 if (eliminate_indirect_cycles (i) && find (i) != i)
2635 /* If the node has changed, we need to process the
2636 complex constraints and outgoing edges again. */
2637 if (TEST_BIT (changed, i))
2642 VEC(constraint_t,heap) *complex = graph->complex[i];
2643 bool solution_empty;
2645 RESET_BIT (changed, i);
2648 /* Compute the changed set of solution bits. */
2649 bitmap_and_compl (pts, get_varinfo (i)->solution,
2650 get_varinfo (i)->oldsolution);
2652 if (bitmap_empty_p (pts))
2655 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2657 solution = get_varinfo (i)->solution;
2658 solution_empty = bitmap_empty_p (solution);
2660 /* Process the complex constraints */
2661 for (j = 0; VEC_iterate (constraint_t, complex, j, c); j++)
2663 /* XXX: This is going to unsort the constraints in
2664 some cases, which will occasionally add duplicate
2665 constraints during unification. This does not
2666 affect correctness. */
2667 c->lhs.var = find (c->lhs.var);
2668 c->rhs.var = find (c->rhs.var);
2670 /* The only complex constraint that can change our
2671 solution to non-empty, given an empty solution,
2672 is a constraint where the lhs side is receiving
2673 some set from elsewhere. */
2674 if (!solution_empty || c->lhs.type != DEREF)
2675 do_complex_constraint (graph, c, pts);
2678 solution_empty = bitmap_empty_p (solution);
2680 if (!solution_empty)
2683 unsigned eff_escaped_id = find (escaped_id);
2685 /* Propagate solution to all successors. */
2686 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2692 unsigned int to = find (j);
2693 tmp = get_varinfo (to)->solution;
2696 /* Don't try to propagate to ourselves. */
2700 /* If we propagate from ESCAPED use ESCAPED as
2702 if (i == eff_escaped_id)
2703 flag = bitmap_set_bit (tmp, escaped_id);
2705 flag = set_union_with_increment (tmp, pts, 0);
2709 get_varinfo (to)->solution = tmp;
2710 if (!TEST_BIT (changed, to))
2712 SET_BIT (changed, to);
2720 free_topo_info (ti);
2721 bitmap_obstack_release (&iteration_obstack);
2725 sbitmap_free (changed);
2726 bitmap_obstack_release (&oldpta_obstack);
2729 /* Map from trees to variable infos. */
2730 static struct pointer_map_t *vi_for_tree;
2733 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2736 insert_vi_for_tree (tree t, varinfo_t vi)
2738 void **slot = pointer_map_insert (vi_for_tree, t);
2740 gcc_assert (*slot == NULL);
2744 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2745 exist in the map, return NULL, otherwise, return the varinfo we found. */
2748 lookup_vi_for_tree (tree t)
2750 void **slot = pointer_map_contains (vi_for_tree, t);
2754 return (varinfo_t) *slot;
2757 /* Return a printable name for DECL */
2760 alias_get_name (tree decl)
2764 int num_printed = 0;
2766 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2767 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2769 res= get_name (decl);
2777 if (TREE_CODE (decl) == SSA_NAME)
2779 num_printed = asprintf (&temp, "%s_%u",
2780 alias_get_name (SSA_NAME_VAR (decl)),
2781 SSA_NAME_VERSION (decl));
2783 else if (DECL_P (decl))
2785 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2787 if (num_printed > 0)
2789 res = ggc_strdup (temp);
2795 /* Find the variable id for tree T in the map.
2796 If T doesn't exist in the map, create an entry for it and return it. */
2799 get_vi_for_tree (tree t)
2801 void **slot = pointer_map_contains (vi_for_tree, t);
2803 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2805 return (varinfo_t) *slot;
2808 /* Get a scalar constraint expression for a new temporary variable. */
2810 static struct constraint_expr
2811 new_scalar_tmp_constraint_exp (const char *name)
2813 struct constraint_expr tmp;
2816 vi = new_var_info (NULL_TREE, name);
2820 vi->is_full_var = 1;
2829 /* Get a constraint expression vector from an SSA_VAR_P node.
2830 If address_p is true, the result will be taken its address of. */
2833 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2835 struct constraint_expr cexpr;
2838 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2839 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2841 /* For parameters, get at the points-to set for the actual parm
2843 if (TREE_CODE (t) == SSA_NAME
2844 && TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2845 && SSA_NAME_IS_DEFAULT_DEF (t))
2847 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2851 vi = get_vi_for_tree (t);
2853 cexpr.type = SCALAR;
2855 /* If we determine the result is "anything", and we know this is readonly,
2856 say it points to readonly memory instead. */
2857 if (cexpr.var == anything_id && TREE_READONLY (t))
2860 cexpr.type = ADDRESSOF;
2861 cexpr.var = readonly_id;
2864 /* If we are not taking the address of the constraint expr, add all
2865 sub-fiels of the variable as well. */
2867 && !vi->is_full_var)
2869 for (; vi; vi = vi->next)
2872 VEC_safe_push (ce_s, heap, *results, &cexpr);
2877 VEC_safe_push (ce_s, heap, *results, &cexpr);
2880 /* Process constraint T, performing various simplifications and then
2881 adding it to our list of overall constraints. */
2884 process_constraint (constraint_t t)
2886 struct constraint_expr rhs = t->rhs;
2887 struct constraint_expr lhs = t->lhs;
2889 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2890 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2892 /* If we didn't get any useful constraint from the lhs we get
2893 &ANYTHING as fallback from get_constraint_for. Deal with
2894 it here by turning it into *ANYTHING. */
2895 if (lhs.type == ADDRESSOF
2896 && lhs.var == anything_id)
2899 /* ADDRESSOF on the lhs is invalid. */
2900 gcc_assert (lhs.type != ADDRESSOF);
2902 /* We shouldn't add constraints from things that cannot have pointers.
2903 It's not completely trivial to avoid in the callers, so do it here. */
2904 if (rhs.type != ADDRESSOF
2905 && !get_varinfo (rhs.var)->may_have_pointers)
2908 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2909 if (!get_varinfo (lhs.var)->may_have_pointers)
2912 /* This can happen in our IR with things like n->a = *p */
2913 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2915 /* Split into tmp = *rhs, *lhs = tmp */
2916 struct constraint_expr tmplhs;
2917 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2918 process_constraint (new_constraint (tmplhs, rhs));
2919 process_constraint (new_constraint (lhs, tmplhs));
2921 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2923 /* Split into tmp = &rhs, *lhs = tmp */
2924 struct constraint_expr tmplhs;
2925 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2926 process_constraint (new_constraint (tmplhs, rhs));
2927 process_constraint (new_constraint (lhs, tmplhs));
2931 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2932 VEC_safe_push (constraint_t, heap, constraints, t);
2936 /* Return true if T is a type that could contain pointers. */
2939 type_could_have_pointers (tree type)
2941 if (POINTER_TYPE_P (type))
2944 if (TREE_CODE (type) == ARRAY_TYPE)
2945 return type_could_have_pointers (TREE_TYPE (type));
2947 /* A function or method can consume pointers.
2948 ??? We could be more precise here. */
2949 if (TREE_CODE (type) == FUNCTION_TYPE
2950 || TREE_CODE (type) == METHOD_TYPE)
2953 return AGGREGATE_TYPE_P (type);
2956 /* Return true if T is a variable of a type that could contain
2960 could_have_pointers (tree t)
2962 return (((TREE_CODE (t) == VAR_DECL
2963 || TREE_CODE (t) == PARM_DECL
2964 || TREE_CODE (t) == RESULT_DECL)
2965 && (TREE_PUBLIC (t) || DECL_EXTERNAL (t) || TREE_ADDRESSABLE (t)))
2966 || type_could_have_pointers (TREE_TYPE (t)));
2969 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2972 static HOST_WIDE_INT
2973 bitpos_of_field (const tree fdecl)
2976 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2977 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2980 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2981 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2985 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2986 resulting constraint expressions in *RESULTS. */
2989 get_constraint_for_ptr_offset (tree ptr, tree offset,
2990 VEC (ce_s, heap) **results)
2992 struct constraint_expr c;
2994 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2996 /* If we do not do field-sensitive PTA adding offsets to pointers
2997 does not change the points-to solution. */
2998 if (!use_field_sensitive)
3000 get_constraint_for (ptr, results);
3004 /* If the offset is not a non-negative integer constant that fits
3005 in a HOST_WIDE_INT, we have to fall back to a conservative
3006 solution which includes all sub-fields of all pointed-to
3007 variables of ptr. */
3008 if (offset == NULL_TREE
3009 || !host_integerp (offset, 0))
3010 rhsoffset = UNKNOWN_OFFSET;
3013 /* Make sure the bit-offset also fits. */
3014 rhsunitoffset = TREE_INT_CST_LOW (offset);
3015 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
3016 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
3017 rhsoffset = UNKNOWN_OFFSET;
3020 get_constraint_for (ptr, results);
3024 /* As we are eventually appending to the solution do not use
3025 VEC_iterate here. */
3026 n = VEC_length (ce_s, *results);
3027 for (j = 0; j < n; j++)
3030 c = *VEC_index (ce_s, *results, j);
3031 curr = get_varinfo (c.var);
3033 if (c.type == ADDRESSOF
3034 /* If this varinfo represents a full variable just use it. */
3035 && curr->is_full_var)
3037 else if (c.type == ADDRESSOF
3038 /* If we do not know the offset add all subfields. */
3039 && rhsoffset == UNKNOWN_OFFSET)
3041 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3044 struct constraint_expr c2;
3046 c2.type = ADDRESSOF;
3048 if (c2.var != c.var)
3049 VEC_safe_push (ce_s, heap, *results, &c2);
3054 else if (c.type == ADDRESSOF)
3057 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3059 /* Search the sub-field which overlaps with the
3060 pointed-to offset. If the result is outside of the variable
3061 we have to provide a conservative result, as the variable is
3062 still reachable from the resulting pointer (even though it
3063 technically cannot point to anything). The last and first
3064 sub-fields are such conservative results.
3065 ??? If we always had a sub-field for &object + 1 then
3066 we could represent this in a more precise way. */
3068 && curr->offset < offset)
3070 temp = first_or_preceding_vi_for_offset (curr, offset);
3072 /* If the found variable is not exactly at the pointed to
3073 result, we have to include the next variable in the
3074 solution as well. Otherwise two increments by offset / 2
3075 do not result in the same or a conservative superset
3077 if (temp->offset != offset
3078 && temp->next != NULL)
3080 struct constraint_expr c2;
3081 c2.var = temp->next->id;
3082 c2.type = ADDRESSOF;
3084 VEC_safe_push (ce_s, heap, *results, &c2);
3090 c.offset = rhsoffset;
3092 VEC_replace (ce_s, *results, j, &c);
3097 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3098 If address_p is true the result will be taken its address of. */
3101 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3105 HOST_WIDE_INT bitsize = -1;
3106 HOST_WIDE_INT bitmaxsize = -1;
3107 HOST_WIDE_INT bitpos;
3109 struct constraint_expr *result;
3111 /* Some people like to do cute things like take the address of
3114 while (handled_component_p (forzero)
3115 || INDIRECT_REF_P (forzero))
3116 forzero = TREE_OPERAND (forzero, 0);
3118 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3120 struct constraint_expr temp;
3123 temp.var = integer_id;
3125 VEC_safe_push (ce_s, heap, *results, &temp);
3129 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3131 /* Pretend to take the address of the base, we'll take care of
3132 adding the required subset of sub-fields below. */
3133 get_constraint_for_1 (t, results, true);
3134 gcc_assert (VEC_length (ce_s, *results) == 1);
3135 result = VEC_last (ce_s, *results);
3137 if (result->type == SCALAR
3138 && get_varinfo (result->var)->is_full_var)
3139 /* For single-field vars do not bother about the offset. */
3141 else if (result->type == SCALAR)
3143 /* In languages like C, you can access one past the end of an
3144 array. You aren't allowed to dereference it, so we can
3145 ignore this constraint. When we handle pointer subtraction,
3146 we may have to do something cute here. */
3148 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3151 /* It's also not true that the constraint will actually start at the
3152 right offset, it may start in some padding. We only care about
3153 setting the constraint to the first actual field it touches, so
3155 struct constraint_expr cexpr = *result;
3157 VEC_pop (ce_s, *results);
3159 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3161 if (ranges_overlap_p (curr->offset, curr->size,
3162 bitpos, bitmaxsize))
3164 cexpr.var = curr->id;
3165 VEC_safe_push (ce_s, heap, *results, &cexpr);
3170 /* If we are going to take the address of this field then
3171 to be able to compute reachability correctly add at least
3172 the last field of the variable. */
3174 && VEC_length (ce_s, *results) == 0)
3176 curr = get_varinfo (cexpr.var);
3177 while (curr->next != NULL)
3179 cexpr.var = curr->id;
3180 VEC_safe_push (ce_s, heap, *results, &cexpr);
3183 /* Assert that we found *some* field there. The user couldn't be
3184 accessing *only* padding. */
3185 /* Still the user could access one past the end of an array
3186 embedded in a struct resulting in accessing *only* padding. */
3187 gcc_assert (VEC_length (ce_s, *results) >= 1
3188 || ref_contains_array_ref (orig_t));
3190 else if (bitmaxsize == 0)
3192 if (dump_file && (dump_flags & TDF_DETAILS))
3193 fprintf (dump_file, "Access to zero-sized part of variable,"
3197 if (dump_file && (dump_flags & TDF_DETAILS))
3198 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3200 else if (result->type == DEREF)
3202 /* If we do not know exactly where the access goes say so. Note
3203 that only for non-structure accesses we know that we access
3204 at most one subfiled of any variable. */
3206 || bitsize != bitmaxsize
3207 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t)))
3208 result->offset = UNKNOWN_OFFSET;
3210 result->offset = bitpos;
3212 else if (result->type == ADDRESSOF)
3214 /* We can end up here for component references on a
3215 VIEW_CONVERT_EXPR <>(&foobar). */
3216 result->type = SCALAR;
3217 result->var = anything_id;
3225 /* Dereference the constraint expression CONS, and return the result.
3226 DEREF (ADDRESSOF) = SCALAR
3227 DEREF (SCALAR) = DEREF
3228 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3229 This is needed so that we can handle dereferencing DEREF constraints. */
3232 do_deref (VEC (ce_s, heap) **constraints)
3234 struct constraint_expr *c;
3237 for (i = 0; VEC_iterate (ce_s, *constraints, i, c); i++)
3239 if (c->type == SCALAR)
3241 else if (c->type == ADDRESSOF)
3243 else if (c->type == DEREF)
3245 struct constraint_expr tmplhs;
3246 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3247 process_constraint (new_constraint (tmplhs, *c));
3248 c->var = tmplhs.var;
3255 static void get_constraint_for_1 (tree, VEC (ce_s, heap) **, bool);
3257 /* Given a tree T, return the constraint expression for taking the
3261 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3263 struct constraint_expr *c;
3266 get_constraint_for_1 (t, results, true);
3268 for (i = 0; VEC_iterate (ce_s, *results, i, c); i++)
3270 if (c->type == DEREF)
3273 c->type = ADDRESSOF;
3277 /* Given a tree T, return the constraint expression for it. */
3280 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
3282 struct constraint_expr temp;
3284 /* x = integer is all glommed to a single variable, which doesn't
3285 point to anything by itself. That is, of course, unless it is an
3286 integer constant being treated as a pointer, in which case, we
3287 will return that this is really the addressof anything. This
3288 happens below, since it will fall into the default case. The only
3289 case we know something about an integer treated like a pointer is
3290 when it is the NULL pointer, and then we just say it points to
3293 Do not do that if -fno-delete-null-pointer-checks though, because
3294 in that case *NULL does not fail, so it _should_ alias *anything.
3295 It is not worth adding a new option or renaming the existing one,
3296 since this case is relatively obscure. */
3297 if ((TREE_CODE (t) == INTEGER_CST
3298 && integer_zerop (t))
3299 /* The only valid CONSTRUCTORs in gimple with pointer typed
3300 elements are zero-initializer. But in IPA mode we also
3301 process global initializers, so verify at least. */
3302 || (TREE_CODE (t) == CONSTRUCTOR
3303 && CONSTRUCTOR_NELTS (t) == 0))
3305 if (flag_delete_null_pointer_checks)
3306 temp.var = nothing_id;
3308 temp.var = anything_id;
3309 temp.type = ADDRESSOF;
3311 VEC_safe_push (ce_s, heap, *results, &temp);
3315 /* String constants are read-only. */
3316 if (TREE_CODE (t) == STRING_CST)
3318 temp.var = readonly_id;
3321 VEC_safe_push (ce_s, heap, *results, &temp);
3325 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3327 case tcc_expression:
3329 switch (TREE_CODE (t))
3332 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3340 switch (TREE_CODE (t))
3344 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3349 case ARRAY_RANGE_REF:
3351 get_constraint_for_component_ref (t, results, address_p);
3353 case VIEW_CONVERT_EXPR:
3354 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p);
3356 /* We are missing handling for TARGET_MEM_REF here. */
3361 case tcc_exceptional:
3363 switch (TREE_CODE (t))
3367 get_constraint_for_ssa_var (t, results, address_p);
3374 VEC (ce_s, heap) *tmp = NULL;
3375 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3377 struct constraint_expr *rhsp;
3379 get_constraint_for_1 (val, &tmp, address_p);
3380 for (j = 0; VEC_iterate (ce_s, tmp, j, rhsp); ++j)
3381 VEC_safe_push (ce_s, heap, *results, rhsp);
3382 VEC_truncate (ce_s, tmp, 0);
3384 VEC_free (ce_s, heap, tmp);
3385 /* We do not know whether the constructor was complete,
3386 so technically we have to add &NOTHING or &ANYTHING
3387 like we do for an empty constructor as well. */
3394 case tcc_declaration:
3396 get_constraint_for_ssa_var (t, results, address_p);
3402 /* The default fallback is a constraint from anything. */
3403 temp.type = ADDRESSOF;
3404 temp.var = anything_id;
3406 VEC_safe_push (ce_s, heap, *results, &temp);
3409 /* Given a gimple tree T, return the constraint expression vector for it. */
3412 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3414 gcc_assert (VEC_length (ce_s, *results) == 0);
3416 get_constraint_for_1 (t, results, false);
3420 /* Efficiently generates constraints from all entries in *RHSC to all
3421 entries in *LHSC. */
3424 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3426 struct constraint_expr *lhsp, *rhsp;
3429 if (VEC_length (ce_s, lhsc) <= 1
3430 || VEC_length (ce_s, rhsc) <= 1)
3432 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3433 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); ++j)
3434 process_constraint (new_constraint (*lhsp, *rhsp));
3438 struct constraint_expr tmp;
3439 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3440 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
3441 process_constraint (new_constraint (tmp, *rhsp));
3442 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
3443 process_constraint (new_constraint (*lhsp, tmp));
3447 /* Handle aggregate copies by expanding into copies of the respective
3448 fields of the structures. */
3451 do_structure_copy (tree lhsop, tree rhsop)
3453 struct constraint_expr *lhsp, *rhsp;
3454 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3457 get_constraint_for (lhsop, &lhsc);
3458 get_constraint_for (rhsop, &rhsc);
3459 lhsp = VEC_index (ce_s, lhsc, 0);
3460 rhsp = VEC_index (ce_s, rhsc, 0);
3461 if (lhsp->type == DEREF
3462 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3463 || rhsp->type == DEREF)
3465 if (lhsp->type == DEREF)
3467 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3468 lhsp->offset = UNKNOWN_OFFSET;
3470 if (rhsp->type == DEREF)
3472 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3473 rhsp->offset = UNKNOWN_OFFSET;
3475 process_all_all_constraints (lhsc, rhsc);
3477 else if (lhsp->type == SCALAR
3478 && (rhsp->type == SCALAR
3479 || rhsp->type == ADDRESSOF))
3481 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3482 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3484 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3485 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3486 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3488 varinfo_t lhsv, rhsv;
3489 rhsp = VEC_index (ce_s, rhsc, k);
3490 lhsv = get_varinfo (lhsp->var);
3491 rhsv = get_varinfo (rhsp->var);
3492 if (lhsv->may_have_pointers
3493 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3494 rhsv->offset + lhsoffset, rhsv->size))
3495 process_constraint (new_constraint (*lhsp, *rhsp));
3496 if (lhsv->offset + rhsoffset + lhsv->size
3497 > rhsv->offset + lhsoffset + rhsv->size)
3500 if (k >= VEC_length (ce_s, rhsc))
3510 VEC_free (ce_s, heap, lhsc);
3511 VEC_free (ce_s, heap, rhsc);
3514 /* Create a constraint ID = OP. */
3517 make_constraint_to (unsigned id, tree op)
3519 VEC(ce_s, heap) *rhsc = NULL;
3520 struct constraint_expr *c;
3521 struct constraint_expr includes;
3525 includes.offset = 0;
3526 includes.type = SCALAR;
3528 get_constraint_for (op, &rhsc);
3529 for (j = 0; VEC_iterate (ce_s, rhsc, j, c); j++)
3530 process_constraint (new_constraint (includes, *c));
3531 VEC_free (ce_s, heap, rhsc);
3534 /* Create a constraint ID = &FROM. */
3537 make_constraint_from (varinfo_t vi, int from)
3539 struct constraint_expr lhs, rhs;
3547 rhs.type = ADDRESSOF;
3548 process_constraint (new_constraint (lhs, rhs));
3551 /* Create a constraint ID = FROM. */
3554 make_copy_constraint (varinfo_t vi, int from)
3556 struct constraint_expr lhs, rhs;
3565 process_constraint (new_constraint (lhs, rhs));
3568 /* Make constraints necessary to make OP escape. */
3571 make_escape_constraint (tree op)
3573 make_constraint_to (escaped_id, op);
3576 /* Add constraints to that the solution of VI is transitively closed. */
3579 make_transitive_closure_constraints (varinfo_t vi)
3581 struct constraint_expr lhs, rhs;
3590 process_constraint (new_constraint (lhs, rhs));
3592 /* VAR = VAR + UNKNOWN; */
3598 rhs.offset = UNKNOWN_OFFSET;
3599 process_constraint (new_constraint (lhs, rhs));
3602 /* Create a new artificial heap variable with NAME and make a
3603 constraint from it to LHS. Return the created variable. */
3606 make_heapvar_for (varinfo_t lhs, const char *name)
3609 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3611 if (heapvar == NULL_TREE)
3614 heapvar = create_tmp_var_raw (ptr_type_node, name);
3615 DECL_EXTERNAL (heapvar) = 1;
3617 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3619 ann = get_var_ann (heapvar);
3620 ann->is_heapvar = 1;
3623 /* For global vars we need to add a heapvar to the list of referenced
3624 vars of a different function than it was created for originally. */
3625 if (cfun && gimple_referenced_vars (cfun))
3626 add_referenced_var (heapvar);
3628 vi = new_var_info (heapvar, name);
3629 vi->is_artificial_var = true;
3630 vi->is_heap_var = true;
3631 vi->is_unknown_size_var = true;
3635 vi->is_full_var = true;
3636 insert_vi_for_tree (heapvar, vi);
3641 /* Create a new artificial heap variable with NAME and make a
3642 constraint from it to LHS. Return the created variable. */
3645 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3647 varinfo_t vi = make_heapvar_for (lhs, name);
3648 make_constraint_from (lhs, vi->id);
3653 /* Create a new artificial heap variable with NAME and make a
3654 constraint from it to LHS. Set flags according to a tag used
3655 for tracking restrict pointers. */
3658 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3661 vi = make_constraint_from_heapvar (lhs, name);
3662 vi->is_restrict_var = 1;
3663 vi->is_global_var = 0;
3664 vi->is_special_var = 1;
3665 vi->may_have_pointers = 0;
3668 /* In IPA mode there are varinfos for different aspects of reach
3669 function designator. One for the points-to set of the return
3670 value, one for the variables that are clobbered by the function,
3671 one for its uses and one for each parameter (including a single
3672 glob for remaining variadic arguments). */
3674 enum { fi_clobbers = 1, fi_uses = 2,
3675 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3677 /* Get a constraint for the requested part of a function designator FI
3678 when operating in IPA mode. */
3680 static struct constraint_expr
3681 get_function_part_constraint (varinfo_t fi, unsigned part)
3683 struct constraint_expr c;
3685 gcc_assert (in_ipa_mode);
3687 if (fi->id == anything_id)
3689 /* ??? We probably should have a ANYFN special variable. */
3690 c.var = anything_id;
3694 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3696 varinfo_t ai = first_vi_for_offset (fi, part);
3697 c.var = ai ? ai->id : anything_id;
3711 /* For non-IPA mode, generate constraints necessary for a call on the
3715 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3717 struct constraint_expr rhsc;
3719 bool returns_uses = false;
3721 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3723 tree arg = gimple_call_arg (stmt, i);
3724 int flags = gimple_call_arg_flags (stmt, i);
3726 /* If the argument is not used or it does not contain pointers
3727 we can ignore it. */
3728 if ((flags & EAF_UNUSED)
3729 || !could_have_pointers (arg))
3732 /* As we compute ESCAPED context-insensitive we do not gain
3733 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3734 set. The argument would still get clobbered through the
3736 ??? We might get away with less (and more precise) constraints
3737 if using a temporary for transitively closing things. */
3738 if ((flags & EAF_NOCLOBBER)
3739 && (flags & EAF_NOESCAPE))
3741 varinfo_t uses = get_call_use_vi (stmt);
3742 if (!(flags & EAF_DIRECT))
3743 make_transitive_closure_constraints (uses);
3744 make_constraint_to (uses->id, arg);
3745 returns_uses = true;
3747 else if (flags & EAF_NOESCAPE)
3749 varinfo_t uses = get_call_use_vi (stmt);
3750 varinfo_t clobbers = get_call_clobber_vi (stmt);
3751 if (!(flags & EAF_DIRECT))
3753 make_transitive_closure_constraints (uses);
3754 make_transitive_closure_constraints (clobbers);
3756 make_constraint_to (uses->id, arg);
3757 make_constraint_to (clobbers->id, arg);
3758 returns_uses = true;
3761 make_escape_constraint (arg);
3764 /* If we added to the calls uses solution make sure we account for
3765 pointers to it to be returned. */
3768 rhsc.var = get_call_use_vi (stmt)->id;
3771 VEC_safe_push (ce_s, heap, *results, &rhsc);
3774 /* The static chain escapes as well. */
3775 if (gimple_call_chain (stmt))
3776 make_escape_constraint (gimple_call_chain (stmt));
3778 /* And if we applied NRV the address of the return slot escapes as well. */
3779 if (gimple_call_return_slot_opt_p (stmt)
3780 && gimple_call_lhs (stmt) != NULL_TREE
3781 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3783 VEC(ce_s, heap) *tmpc = NULL;
3784 struct constraint_expr lhsc, *c;
3785 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3786 lhsc.var = escaped_id;
3789 for (i = 0; VEC_iterate (ce_s, tmpc, i, c); ++i)
3790 process_constraint (new_constraint (lhsc, *c));
3791 VEC_free(ce_s, heap, tmpc);
3794 /* Regular functions return nonlocal memory. */
3795 rhsc.var = nonlocal_id;
3798 VEC_safe_push (ce_s, heap, *results, &rhsc);
3801 /* For non-IPA mode, generate constraints necessary for a call
3802 that returns a pointer and assigns it to LHS. This simply makes
3803 the LHS point to global and escaped variables. */
3806 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3809 VEC(ce_s, heap) *lhsc = NULL;
3811 get_constraint_for (lhs, &lhsc);
3812 /* If the store is to a global decl make sure to
3813 add proper escape constraints. */
3814 lhs = get_base_address (lhs);
3817 && is_global_var (lhs))
3819 struct constraint_expr tmpc;
3820 tmpc.var = escaped_id;
3823 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3826 /* If the call returns an argument unmodified override the rhs
3828 flags = gimple_call_return_flags (stmt);
3829 if (flags & ERF_RETURNS_ARG
3830 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3834 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3835 get_constraint_for (arg, &rhsc);
3836 process_all_all_constraints (lhsc, rhsc);
3837 VEC_free (ce_s, heap, rhsc);
3839 else if (flags & ERF_NOALIAS)
3842 struct constraint_expr tmpc;
3844 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3845 /* We delay marking allocated storage global until we know if
3847 DECL_EXTERNAL (vi->decl) = 0;
3848 vi->is_global_var = 0;
3849 /* If this is not a real malloc call assume the memory was
3850 initialized and thus may point to global memory. All
3851 builtin functions with the malloc attribute behave in a sane way. */
3853 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3854 make_constraint_from (vi, nonlocal_id);
3857 tmpc.type = ADDRESSOF;
3858 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3861 process_all_all_constraints (lhsc, rhsc);
3863 VEC_free (ce_s, heap, lhsc);
3866 /* For non-IPA mode, generate constraints necessary for a call of a
3867 const function that returns a pointer in the statement STMT. */
3870 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3872 struct constraint_expr rhsc;
3875 /* Treat nested const functions the same as pure functions as far
3876 as the static chain is concerned. */
3877 if (gimple_call_chain (stmt))
3879 varinfo_t uses = get_call_use_vi (stmt);
3880 make_transitive_closure_constraints (uses);
3881 make_constraint_to (uses->id, gimple_call_chain (stmt));
3882 rhsc.var = uses->id;
3885 VEC_safe_push (ce_s, heap, *results, &rhsc);
3888 /* May return arguments. */
3889 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3891 tree arg = gimple_call_arg (stmt, k);
3893 if (could_have_pointers (arg))
3895 VEC(ce_s, heap) *argc = NULL;
3897 struct constraint_expr *argp;
3898 get_constraint_for (arg, &argc);
3899 for (i = 0; VEC_iterate (ce_s, argc, i, argp); ++i)
3900 VEC_safe_push (ce_s, heap, *results, argp);
3901 VEC_free(ce_s, heap, argc);
3905 /* May return addresses of globals. */
3906 rhsc.var = nonlocal_id;
3908 rhsc.type = ADDRESSOF;
3909 VEC_safe_push (ce_s, heap, *results, &rhsc);
3912 /* For non-IPA mode, generate constraints necessary for a call to a
3913 pure function in statement STMT. */
3916 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3918 struct constraint_expr rhsc;
3920 varinfo_t uses = NULL;
3922 /* Memory reached from pointer arguments is call-used. */
3923 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3925 tree arg = gimple_call_arg (stmt, i);
3927 if (could_have_pointers (arg))
3931 uses = get_call_use_vi (stmt);
3932 make_transitive_closure_constraints (uses);
3934 make_constraint_to (uses->id, arg);
3938 /* The static chain is used as well. */
3939 if (gimple_call_chain (stmt))
3943 uses = get_call_use_vi (stmt);
3944 make_transitive_closure_constraints (uses);
3946 make_constraint_to (uses->id, gimple_call_chain (stmt));
3949 /* Pure functions may return call-used and nonlocal memory. */
3952 rhsc.var = uses->id;
3955 VEC_safe_push (ce_s, heap, *results, &rhsc);
3957 rhsc.var = nonlocal_id;
3960 VEC_safe_push (ce_s, heap, *results, &rhsc);
3964 /* Return the varinfo for the callee of CALL. */
3967 get_fi_for_callee (gimple call)
3971 /* If we can directly resolve the function being called, do so.
3972 Otherwise, it must be some sort of indirect expression that
3973 we should still be able to handle. */
3974 decl = gimple_call_fndecl (call);
3976 return get_vi_for_tree (decl);
3978 decl = gimple_call_fn (call);
3979 /* The function can be either an SSA name pointer or,
3980 worse, an OBJ_TYPE_REF. In this case we have no
3981 clue and should be getting ANYFN (well, ANYTHING for now). */
3982 if (TREE_CODE (decl) == SSA_NAME)
3984 if (TREE_CODE (decl) == SSA_NAME
3985 && TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3986 && SSA_NAME_IS_DEFAULT_DEF (decl))
3987 decl = SSA_NAME_VAR (decl);
3988 return get_vi_for_tree (decl);
3990 else if (TREE_CODE (decl) == INTEGER_CST
3991 || TREE_CODE (decl) == OBJ_TYPE_REF)
3992 return get_varinfo (anything_id);
3997 /* Walk statement T setting up aliasing constraints according to the
3998 references found in T. This function is the main part of the
3999 constraint builder. AI points to auxiliary alias information used
4000 when building alias sets and computing alias grouping heuristics. */
4003 find_func_aliases (gimple origt)
4006 VEC(ce_s, heap) *lhsc = NULL;
4007 VEC(ce_s, heap) *rhsc = NULL;
4008 struct constraint_expr *c;
4011 /* Now build constraints expressions. */
4012 if (gimple_code (t) == GIMPLE_PHI)
4014 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4016 /* Only care about pointers and structures containing
4018 if (could_have_pointers (gimple_phi_result (t)))
4023 /* For a phi node, assign all the arguments to
4025 get_constraint_for (gimple_phi_result (t), &lhsc);
4026 for (i = 0; i < gimple_phi_num_args (t); i++)
4028 tree strippedrhs = PHI_ARG_DEF (t, i);
4030 STRIP_NOPS (strippedrhs);
4031 get_constraint_for (gimple_phi_arg_def (t, i), &rhsc);
4033 for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
4035 struct constraint_expr *c2;
4036 while (VEC_length (ce_s, rhsc) > 0)
4038 c2 = VEC_last (ce_s, rhsc);
4039 process_constraint (new_constraint (*c, *c2));
4040 VEC_pop (ce_s, rhsc);
4046 /* In IPA mode, we need to generate constraints to pass call
4047 arguments through their calls. There are two cases,
4048 either a GIMPLE_CALL returning a value, or just a plain
4049 GIMPLE_CALL when we are not.
4051 In non-ipa mode, we need to generate constraints for each
4052 pointer passed by address. */
4053 else if (is_gimple_call (t))
4055 tree fndecl = gimple_call_fndecl (t);
4056 if (fndecl != NULL_TREE
4057 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4058 /* ??? All builtins that are handled here need to be handled
4059 in the alias-oracle query functions explicitly! */
4060 switch (DECL_FUNCTION_CODE (fndecl))
4062 /* All the following functions return a pointer to the same object
4063 as their first argument points to. The functions do not add
4064 to the ESCAPED solution. The functions make the first argument
4065 pointed to memory point to what the second argument pointed to
4066 memory points to. */
4067 case BUILT_IN_STRCPY:
4068 case BUILT_IN_STRNCPY:
4069 case BUILT_IN_BCOPY:
4070 case BUILT_IN_MEMCPY:
4071 case BUILT_IN_MEMMOVE:
4072 case BUILT_IN_MEMPCPY:
4073 case BUILT_IN_STPCPY:
4074 case BUILT_IN_STPNCPY:
4075 case BUILT_IN_STRCAT:
4076 case BUILT_IN_STRNCAT:
4078 tree res = gimple_call_lhs (t);
4079 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4080 == BUILT_IN_BCOPY ? 1 : 0));
4081 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4082 == BUILT_IN_BCOPY ? 0 : 1));
4083 if (res != NULL_TREE)
4085 get_constraint_for (res, &lhsc);
4086 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4087 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4088 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4089 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4091 get_constraint_for (dest, &rhsc);
4092 process_all_all_constraints (lhsc, rhsc);
4093 VEC_free (ce_s, heap, lhsc);
4094 VEC_free (ce_s, heap, rhsc);
4096 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4097 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4100 process_all_all_constraints (lhsc, rhsc);
4101 VEC_free (ce_s, heap, lhsc);
4102 VEC_free (ce_s, heap, rhsc);
4105 case BUILT_IN_MEMSET:
4107 tree res = gimple_call_lhs (t);
4108 tree dest = gimple_call_arg (t, 0);
4111 struct constraint_expr ac;
4112 if (res != NULL_TREE)
4114 get_constraint_for (res, &lhsc);
4115 get_constraint_for (dest, &rhsc);
4116 process_all_all_constraints (lhsc, rhsc);
4117 VEC_free (ce_s, heap, lhsc);
4118 VEC_free (ce_s, heap, rhsc);
4120 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4122 if (flag_delete_null_pointer_checks
4123 && integer_zerop (gimple_call_arg (t, 1)))
4125 ac.type = ADDRESSOF;
4126 ac.var = nothing_id;
4131 ac.var = integer_id;
4134 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4135 process_constraint (new_constraint (*lhsp, ac));
4136 VEC_free (ce_s, heap, lhsc);
4139 /* All the following functions do not return pointers, do not
4140 modify the points-to sets of memory reachable from their
4141 arguments and do not add to the ESCAPED solution. */
4142 case BUILT_IN_SINCOS:
4143 case BUILT_IN_SINCOSF:
4144 case BUILT_IN_SINCOSL:
4145 case BUILT_IN_FREXP:
4146 case BUILT_IN_FREXPF:
4147 case BUILT_IN_FREXPL:
4148 case BUILT_IN_GAMMA_R:
4149 case BUILT_IN_GAMMAF_R:
4150 case BUILT_IN_GAMMAL_R:
4151 case BUILT_IN_LGAMMA_R:
4152 case BUILT_IN_LGAMMAF_R:
4153 case BUILT_IN_LGAMMAL_R:
4155 case BUILT_IN_MODFF:
4156 case BUILT_IN_MODFL:
4157 case BUILT_IN_REMQUO:
4158 case BUILT_IN_REMQUOF:
4159 case BUILT_IN_REMQUOL:
4162 /* Trampolines are special - they set up passing the static
4164 case BUILT_IN_INIT_TRAMPOLINE:
4166 tree tramp = gimple_call_arg (t, 0);
4167 tree nfunc = gimple_call_arg (t, 1);
4168 tree frame = gimple_call_arg (t, 2);
4170 struct constraint_expr lhs, *rhsp;
4173 varinfo_t nfi = NULL;
4174 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4175 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4178 lhs = get_function_part_constraint (nfi, fi_static_chain);
4179 get_constraint_for (frame, &rhsc);
4180 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
4181 process_constraint (new_constraint (lhs, *rhsp));
4182 VEC_free (ce_s, heap, rhsc);
4184 /* Make the frame point to the function for
4185 the trampoline adjustment call. */
4186 get_constraint_for (tramp, &lhsc);
4188 get_constraint_for (nfunc, &rhsc);
4189 process_all_all_constraints (lhsc, rhsc);
4190 VEC_free (ce_s, heap, rhsc);
4191 VEC_free (ce_s, heap, lhsc);
4196 /* Else fallthru to generic handling which will let
4197 the frame escape. */
4200 case BUILT_IN_ADJUST_TRAMPOLINE:
4202 tree tramp = gimple_call_arg (t, 0);
4203 tree res = gimple_call_lhs (t);
4204 if (in_ipa_mode && res)
4206 get_constraint_for (res, &lhsc);
4207 get_constraint_for (tramp, &rhsc);
4209 process_all_all_constraints (lhsc, rhsc);
4210 VEC_free (ce_s, heap, rhsc);
4211 VEC_free (ce_s, heap, lhsc);
4215 /* Variadic argument handling needs to be handled in IPA
4217 case BUILT_IN_VA_START:
4221 tree valist = gimple_call_arg (t, 0);
4222 struct constraint_expr rhs, *lhsp;
4224 /* The va_list gets access to pointers in variadic
4226 fi = lookup_vi_for_tree (cfun->decl);
4227 gcc_assert (fi != NULL);
4228 get_constraint_for (valist, &lhsc);
4230 rhs = get_function_part_constraint (fi, ~0);
4231 rhs.type = ADDRESSOF;
4232 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); ++i)
4233 process_constraint (new_constraint (*lhsp, rhs));
4234 VEC_free (ce_s, heap, lhsc);
4235 /* va_list is clobbered. */
4236 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4241 /* va_end doesn't have any effect that matters. */
4242 case BUILT_IN_VA_END:
4244 /* printf-style functions may have hooks to set pointers to
4245 point to somewhere into the generated string. Leave them
4246 for a later excercise... */
4248 /* Fallthru to general call handling. */;
4252 && (!(fi = lookup_vi_for_tree (fndecl))
4253 || !fi->is_fn_info)))
4255 VEC(ce_s, heap) *rhsc = NULL;
4256 int flags = gimple_call_flags (t);
4258 /* Const functions can return their arguments and addresses
4259 of global memory but not of escaped memory. */
4260 if (flags & (ECF_CONST|ECF_NOVOPS))
4262 if (gimple_call_lhs (t)
4263 && could_have_pointers (gimple_call_lhs (t)))
4264 handle_const_call (t, &rhsc);
4266 /* Pure functions can return addresses in and of memory
4267 reachable from their arguments, but they are not an escape
4268 point for reachable memory of their arguments. */
4269 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4270 handle_pure_call (t, &rhsc);
4272 handle_rhs_call (t, &rhsc);
4273 if (gimple_call_lhs (t)
4274 && could_have_pointers (gimple_call_lhs (t)))
4275 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4276 VEC_free (ce_s, heap, rhsc);
4283 fi = get_fi_for_callee (t);
4285 /* Assign all the passed arguments to the appropriate incoming
4286 parameters of the function. */
4287 for (j = 0; j < gimple_call_num_args (t); j++)
4289 struct constraint_expr lhs ;
4290 struct constraint_expr *rhsp;
4291 tree arg = gimple_call_arg (t, j);
4293 if (!could_have_pointers (arg))
4296 get_constraint_for (arg, &rhsc);
4297 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4298 while (VEC_length (ce_s, rhsc) != 0)
4300 rhsp = VEC_last (ce_s, rhsc);
4301 process_constraint (new_constraint (lhs, *rhsp));
4302 VEC_pop (ce_s, rhsc);
4306 /* If we are returning a value, assign it to the result. */
4307 lhsop = gimple_call_lhs (t);
4309 && could_have_pointers (lhsop))
4311 struct constraint_expr rhs;
4312 struct constraint_expr *lhsp;
4314 get_constraint_for (lhsop, &lhsc);
4315 rhs = get_function_part_constraint (fi, fi_result);
4317 && DECL_RESULT (fndecl)
4318 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4320 VEC(ce_s, heap) *tem = NULL;
4321 VEC_safe_push (ce_s, heap, tem, &rhs);
4323 rhs = *VEC_index (ce_s, tem, 0);
4324 VEC_free(ce_s, heap, tem);
4326 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4327 process_constraint (new_constraint (*lhsp, rhs));
4330 /* If we pass the result decl by reference, honor that. */
4333 && DECL_RESULT (fndecl)
4334 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4336 struct constraint_expr lhs;
4337 struct constraint_expr *rhsp;
4339 get_constraint_for_address_of (lhsop, &rhsc);
4340 lhs = get_function_part_constraint (fi, fi_result);
4341 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4342 process_constraint (new_constraint (lhs, *rhsp));
4343 VEC_free (ce_s, heap, rhsc);
4346 /* If we use a static chain, pass it along. */
4347 if (gimple_call_chain (t))
4349 struct constraint_expr lhs;
4350 struct constraint_expr *rhsp;
4352 get_constraint_for (gimple_call_chain (t), &rhsc);
4353 lhs = get_function_part_constraint (fi, fi_static_chain);
4354 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4355 process_constraint (new_constraint (lhs, *rhsp));
4359 /* Otherwise, just a regular assignment statement. Only care about
4360 operations with pointer result, others are dealt with as escape
4361 points if they have pointer operands. */
4362 else if (is_gimple_assign (t)
4363 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4365 /* Otherwise, just a regular assignment statement. */
4366 tree lhsop = gimple_assign_lhs (t);
4367 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4369 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4370 do_structure_copy (lhsop, rhsop);
4373 struct constraint_expr temp;
4374 get_constraint_for (lhsop, &lhsc);
4376 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4377 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4378 gimple_assign_rhs2 (t), &rhsc);
4379 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4380 && !(POINTER_TYPE_P (gimple_expr_type (t))
4381 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4382 || gimple_assign_single_p (t))
4383 get_constraint_for (rhsop, &rhsc);
4386 temp.type = ADDRESSOF;
4387 temp.var = anything_id;
4389 VEC_safe_push (ce_s, heap, rhsc, &temp);
4391 process_all_all_constraints (lhsc, rhsc);
4393 /* If there is a store to a global variable the rhs escapes. */
4394 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4396 && is_global_var (lhsop)
4398 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4399 make_escape_constraint (rhsop);
4400 /* If this is a conversion of a non-restrict pointer to a
4401 restrict pointer track it with a new heapvar. */
4402 else if (gimple_assign_cast_p (t)
4403 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4404 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4405 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4406 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4407 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4410 /* For conversions of pointers to non-pointers the pointer escapes. */
4411 else if (gimple_assign_cast_p (t)
4412 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4413 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4415 make_escape_constraint (gimple_assign_rhs1 (t));
4417 /* Handle escapes through return. */
4418 else if (gimple_code (t) == GIMPLE_RETURN
4419 && gimple_return_retval (t) != NULL_TREE
4420 && could_have_pointers (gimple_return_retval (t)))
4424 || !(fi = get_vi_for_tree (cfun->decl)))
4425 make_escape_constraint (gimple_return_retval (t));
4426 else if (in_ipa_mode
4429 struct constraint_expr lhs ;
4430 struct constraint_expr *rhsp;
4433 lhs = get_function_part_constraint (fi, fi_result);
4434 get_constraint_for (gimple_return_retval (t), &rhsc);
4435 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4436 process_constraint (new_constraint (lhs, *rhsp));
4439 /* Handle asms conservatively by adding escape constraints to everything. */
4440 else if (gimple_code (t) == GIMPLE_ASM)
4442 unsigned i, noutputs;
4443 const char **oconstraints;
4444 const char *constraint;
4445 bool allows_mem, allows_reg, is_inout;
4447 noutputs = gimple_asm_noutputs (t);
4448 oconstraints = XALLOCAVEC (const char *, noutputs);
4450 for (i = 0; i < noutputs; ++i)
4452 tree link = gimple_asm_output_op (t, i);
4453 tree op = TREE_VALUE (link);
4455 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4456 oconstraints[i] = constraint;
4457 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4458 &allows_reg, &is_inout);
4460 /* A memory constraint makes the address of the operand escape. */
4461 if (!allows_reg && allows_mem)
4462 make_escape_constraint (build_fold_addr_expr (op));
4464 /* The asm may read global memory, so outputs may point to
4465 any global memory. */
4466 if (op && could_have_pointers (op))
4468 VEC(ce_s, heap) *lhsc = NULL;
4469 struct constraint_expr rhsc, *lhsp;
4471 get_constraint_for (op, &lhsc);
4472 rhsc.var = nonlocal_id;
4475 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp); j++)
4476 process_constraint (new_constraint (*lhsp, rhsc));
4477 VEC_free (ce_s, heap, lhsc);
4480 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4482 tree link = gimple_asm_input_op (t, i);
4483 tree op = TREE_VALUE (link);
4485 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4487 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4488 &allows_mem, &allows_reg);
4490 /* A memory constraint makes the address of the operand escape. */
4491 if (!allows_reg && allows_mem)
4492 make_escape_constraint (build_fold_addr_expr (op));
4493 /* Strictly we'd only need the constraint to ESCAPED if
4494 the asm clobbers memory, otherwise using something
4495 along the lines of per-call clobbers/uses would be enough. */
4496 else if (op && could_have_pointers (op))
4497 make_escape_constraint (op);
4501 VEC_free (ce_s, heap, rhsc);
4502 VEC_free (ce_s, heap, lhsc);
4506 /* Create a constraint adding to the clobber set of FI the memory
4507 pointed to by PTR. */
4510 process_ipa_clobber (varinfo_t fi, tree ptr)
4512 VEC(ce_s, heap) *ptrc = NULL;
4513 struct constraint_expr *c, lhs;
4515 get_constraint_for (ptr, &ptrc);
4516 lhs = get_function_part_constraint (fi, fi_clobbers);
4517 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4518 process_constraint (new_constraint (lhs, *c));
4519 VEC_free (ce_s, heap, ptrc);
4522 /* Walk statement T setting up clobber and use constraints according to the
4523 references found in T. This function is a main part of the
4524 IPA constraint builder. */
4527 find_func_clobbers (gimple origt)
4530 VEC(ce_s, heap) *lhsc = NULL;
4531 VEC(ce_s, heap) *rhsc = NULL;
4534 /* Add constraints for clobbered/used in IPA mode.
4535 We are not interested in what automatic variables are clobbered
4536 or used as we only use the information in the caller to which
4537 they do not escape. */
4538 gcc_assert (in_ipa_mode);
4540 /* If the stmt refers to memory in any way it better had a VUSE. */
4541 if (gimple_vuse (t) == NULL_TREE)
4544 /* We'd better have function information for the current function. */
4545 fi = lookup_vi_for_tree (cfun->decl);
4546 gcc_assert (fi != NULL);
4548 /* Account for stores in assignments and calls. */
4549 if (gimple_vdef (t) != NULL_TREE
4550 && gimple_has_lhs (t))
4552 tree lhs = gimple_get_lhs (t);
4554 while (handled_component_p (tem))
4555 tem = TREE_OPERAND (tem, 0);
4557 && !auto_var_in_fn_p (tem, cfun->decl))
4558 || INDIRECT_REF_P (tem))
4560 struct constraint_expr lhsc, *rhsp;
4562 lhsc = get_function_part_constraint (fi, fi_clobbers);
4563 get_constraint_for_address_of (lhs, &rhsc);
4564 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4565 process_constraint (new_constraint (lhsc, *rhsp));
4566 VEC_free (ce_s, heap, rhsc);
4570 /* Account for uses in assigments and returns. */
4571 if (gimple_assign_single_p (t)
4572 || (gimple_code (t) == GIMPLE_RETURN
4573 && gimple_return_retval (t) != NULL_TREE))
4575 tree rhs = (gimple_assign_single_p (t)
4576 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4578 while (handled_component_p (tem))
4579 tem = TREE_OPERAND (tem, 0);
4581 && !auto_var_in_fn_p (tem, cfun->decl))
4582 || INDIRECT_REF_P (tem))
4584 struct constraint_expr lhs, *rhsp;
4586 lhs = get_function_part_constraint (fi, fi_uses);
4587 get_constraint_for_address_of (rhs, &rhsc);
4588 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4589 process_constraint (new_constraint (lhs, *rhsp));
4590 VEC_free (ce_s, heap, rhsc);
4594 if (is_gimple_call (t))
4596 varinfo_t cfi = NULL;
4597 tree decl = gimple_call_fndecl (t);
4598 struct constraint_expr lhs, rhs;
4601 /* For builtins we do not have separate function info. For those
4602 we do not generate escapes for we have to generate clobbers/uses. */
4604 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4605 switch (DECL_FUNCTION_CODE (decl))
4607 /* The following functions use and clobber memory pointed to
4608 by their arguments. */
4609 case BUILT_IN_STRCPY:
4610 case BUILT_IN_STRNCPY:
4611 case BUILT_IN_BCOPY:
4612 case BUILT_IN_MEMCPY:
4613 case BUILT_IN_MEMMOVE:
4614 case BUILT_IN_MEMPCPY:
4615 case BUILT_IN_STPCPY:
4616 case BUILT_IN_STPNCPY:
4617 case BUILT_IN_STRCAT:
4618 case BUILT_IN_STRNCAT:
4620 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4621 == BUILT_IN_BCOPY ? 1 : 0));
4622 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4623 == BUILT_IN_BCOPY ? 0 : 1));
4625 struct constraint_expr *rhsp, *lhsp;
4626 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4627 lhs = get_function_part_constraint (fi, fi_clobbers);
4628 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4629 process_constraint (new_constraint (lhs, *lhsp));
4630 VEC_free (ce_s, heap, lhsc);
4631 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4632 lhs = get_function_part_constraint (fi, fi_uses);
4633 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); i++)
4634 process_constraint (new_constraint (lhs, *rhsp));
4635 VEC_free (ce_s, heap, rhsc);
4638 /* The following function clobbers memory pointed to by
4640 case BUILT_IN_MEMSET:
4642 tree dest = gimple_call_arg (t, 0);
4645 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4646 lhs = get_function_part_constraint (fi, fi_clobbers);
4647 for (i = 0; VEC_iterate (ce_s, lhsc, i, lhsp); i++)
4648 process_constraint (new_constraint (lhs, *lhsp));
4649 VEC_free (ce_s, heap, lhsc);
4652 /* The following functions clobber their second and third
4654 case BUILT_IN_SINCOS:
4655 case BUILT_IN_SINCOSF:
4656 case BUILT_IN_SINCOSL:
4658 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4659 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4662 /* The following functions clobber their second argument. */
4663 case BUILT_IN_FREXP:
4664 case BUILT_IN_FREXPF:
4665 case BUILT_IN_FREXPL:
4666 case BUILT_IN_LGAMMA_R:
4667 case BUILT_IN_LGAMMAF_R:
4668 case BUILT_IN_LGAMMAL_R:
4669 case BUILT_IN_GAMMA_R:
4670 case BUILT_IN_GAMMAF_R:
4671 case BUILT_IN_GAMMAL_R:
4673 case BUILT_IN_MODFF:
4674 case BUILT_IN_MODFL:
4676 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4679 /* The following functions clobber their third argument. */
4680 case BUILT_IN_REMQUO:
4681 case BUILT_IN_REMQUOF:
4682 case BUILT_IN_REMQUOL:
4684 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4687 /* The following functions neither read nor clobber memory. */
4690 /* Trampolines are of no interest to us. */
4691 case BUILT_IN_INIT_TRAMPOLINE:
4692 case BUILT_IN_ADJUST_TRAMPOLINE:
4694 case BUILT_IN_VA_START:
4695 case BUILT_IN_VA_END:
4697 /* printf-style functions may have hooks to set pointers to
4698 point to somewhere into the generated string. Leave them
4699 for a later excercise... */
4701 /* Fallthru to general call handling. */;
4704 /* Parameters passed by value are used. */
4705 lhs = get_function_part_constraint (fi, fi_uses);
4706 for (i = 0; i < gimple_call_num_args (t); i++)
4708 struct constraint_expr *rhsp;
4709 tree arg = gimple_call_arg (t, i);
4711 if (TREE_CODE (arg) == SSA_NAME
4712 || is_gimple_min_invariant (arg))
4715 get_constraint_for_address_of (arg, &rhsc);
4716 for (j = 0; VEC_iterate (ce_s, rhsc, j, rhsp); j++)
4717 process_constraint (new_constraint (lhs, *rhsp));
4718 VEC_free (ce_s, heap, rhsc);
4721 /* Build constraints for propagating clobbers/uses along the
4723 cfi = get_fi_for_callee (t);
4724 if (cfi->id == anything_id)
4726 if (gimple_vdef (t))
4727 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4729 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4734 /* For callees without function info (that's external functions),
4735 ESCAPED is clobbered and used. */
4736 if (gimple_call_fndecl (t)
4737 && !cfi->is_fn_info)
4741 if (gimple_vdef (t))
4742 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4744 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4746 /* Also honor the call statement use/clobber info. */
4747 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4748 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4750 if ((vi = lookup_call_use_vi (t)) != NULL)
4751 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4756 /* Otherwise the caller clobbers and uses what the callee does.
4757 ??? This should use a new complex constraint that filters
4758 local variables of the callee. */
4759 if (gimple_vdef (t))
4761 lhs = get_function_part_constraint (fi, fi_clobbers);
4762 rhs = get_function_part_constraint (cfi, fi_clobbers);
4763 process_constraint (new_constraint (lhs, rhs));
4765 lhs = get_function_part_constraint (fi, fi_uses);
4766 rhs = get_function_part_constraint (cfi, fi_uses);
4767 process_constraint (new_constraint (lhs, rhs));
4769 else if (gimple_code (t) == GIMPLE_ASM)
4771 /* ??? Ick. We can do better. */
4772 if (gimple_vdef (t))
4773 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4775 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4779 VEC_free (ce_s, heap, rhsc);
4783 /* Find the first varinfo in the same variable as START that overlaps with
4784 OFFSET. Return NULL if we can't find one. */
4787 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4789 /* If the offset is outside of the variable, bail out. */
4790 if (offset >= start->fullsize)
4793 /* If we cannot reach offset from start, lookup the first field
4794 and start from there. */
4795 if (start->offset > offset)
4796 start = lookup_vi_for_tree (start->decl);
4800 /* We may not find a variable in the field list with the actual
4801 offset when when we have glommed a structure to a variable.
4802 In that case, however, offset should still be within the size
4804 if (offset >= start->offset
4805 && (offset - start->offset) < start->size)
4814 /* Find the first varinfo in the same variable as START that overlaps with
4815 OFFSET. If there is no such varinfo the varinfo directly preceding
4816 OFFSET is returned. */
4819 process_ipa_clobber (varinfo_t fi, tree ptr)
4821 VEC(ce_s, heap) *ptrc = NULL;
4822 struct constraint_expr *c, lhs;
4824 get_constraint_for (ptr, &ptrc);
4825 lhs = get_function_part_constraint (fi, fi_clobbers);
4826 for (i = 0; VEC_iterate (ce_s, ptrc, i, c); i++)
4827 process_constraint (new_constraint (lhs, *c));
4828 VEC_free (ce_s, heap, ptrc);
4831 /* Walk statement T setting up clobber and use constraints according to the
4832 references found in T. This function is a main part of the
4833 IPA constraint builder. */
4836 find_func_clobbers (gimple origt)
4839 VEC(ce_s, heap) *lhsc = NULL;
4840 VEC(ce_s, heap) *rhsc = NULL;
4843 /* Add constraints for clobbered/used in IPA mode.
4844 We are not interested in what automatic variables are clobbered
4845 or used as we only use the information in the caller to which
4846 they do not escape. */
4847 gcc_assert (in_ipa_mode);
4849 /* This structure is used during pushing fields onto the fieldstack
4850 to track the offset of the field, since bitpos_of_field gives it
4851 relative to its immediate containing type, and we want it relative
4852 to the ultimate containing object. */
4856 /* Offset from the base of the base containing object to this field. */
4857 HOST_WIDE_INT offset;
4859 /* Size, in bits, of the field. */
4860 unsigned HOST_WIDE_INT size;
4862 unsigned has_unknown_size : 1;
4864 unsigned may_have_pointers : 1;
4866 unsigned only_restrict_pointers : 1;
4868 typedef struct fieldoff fieldoff_s;
4870 DEF_VEC_O(fieldoff_s);
4871 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4873 /* qsort comparison function for two fieldoff's PA and PB */
4876 fieldoff_compare (const void *pa, const void *pb)
4878 const fieldoff_s *foa = (const fieldoff_s *)pa;
4879 const fieldoff_s *fob = (const fieldoff_s *)pb;
4880 unsigned HOST_WIDE_INT foasize, fobsize;
4882 if (foa->offset < fob->offset)
4884 else if (foa->offset > fob->offset)
4887 foasize = foa->size;
4888 fobsize = fob->size;
4889 if (foasize < fobsize)
4891 else if (foasize > fobsize)
4896 /* Sort a fieldstack according to the field offset and sizes. */
4898 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4900 qsort (VEC_address (fieldoff_s, fieldstack),
4901 VEC_length (fieldoff_s, fieldstack),
4902 sizeof (fieldoff_s),
4906 /* Return true if V is a tree that we can have subvars for.
4907 Normally, this is any aggregate type. Also complex
4908 types which are not gimple registers can have subvars. */
4911 var_can_have_subvars (const_tree v)
4913 /* Volatile variables should never have subvars. */
4914 if (TREE_THIS_VOLATILE (v))
4917 /* Non decls or memory tags can never have subvars. */
4921 /* Aggregates without overlapping fields can have subvars. */
4922 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4928 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4929 the fields of TYPE onto fieldstack, recording their offsets along
4932 OFFSET is used to keep track of the offset in this entire
4933 structure, rather than just the immediately containing structure.
4934 Returns false if the caller is supposed to handle the field we
4938 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4939 HOST_WIDE_INT offset, bool must_have_pointers_p)
4942 bool empty_p = true;
4944 if (TREE_CODE (type) != RECORD_TYPE)
4947 /* If the vector of fields is growing too big, bail out early.
4948 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4950 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4953 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
4954 if (TREE_CODE (field) == FIELD_DECL)
4957 HOST_WIDE_INT foff = bitpos_of_field (field);
4959 if (!var_can_have_subvars (field)
4960 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
4961 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
4963 else if (!push_fields_onto_fieldstack
4964 (TREE_TYPE (field), fieldstack, offset + foff,
4965 must_have_pointers_p)
4966 && (DECL_SIZE (field)
4967 && !integer_zerop (DECL_SIZE (field))))
4968 /* Empty structures may have actual size, like in C++. So
4969 see if we didn't push any subfields and the size is
4970 nonzero, push the field onto the stack. */
4975 fieldoff_s *pair = NULL;
4976 bool has_unknown_size = false;
4978 if (!VEC_empty (fieldoff_s, *fieldstack))
4979 pair = VEC_last (fieldoff_s, *fieldstack);
4981 if (!DECL_SIZE (field)
4982 || !host_integerp (DECL_SIZE (field), 1))
4983 has_unknown_size = true;
4985 /* If adjacent fields do not contain pointers merge them. */
4987 && !pair->may_have_pointers
4988 && !pair->has_unknown_size
4989 && !has_unknown_size
4990 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
4991 && !must_have_pointers_p
4992 && !could_have_pointers (field))
4994 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
4998 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
4999 pair->offset = offset + foff;
5000 pair->has_unknown_size = has_unknown_size;
5001 if (!has_unknown_size)
5002 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5005 pair->may_have_pointers
5006 = must_have_pointers_p || could_have_pointers (field);
5007 pair->only_restrict_pointers
5008 = (!has_unknown_size
5009 && POINTER_TYPE_P (TREE_TYPE (field))
5010 && TYPE_RESTRICT (TREE_TYPE (field)));
5020 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5021 if it is a varargs function. */
5024 count_num_arguments (tree decl, bool *is_varargs)
5026 unsigned int num = 0;
5029 /* Capture named arguments for K&R functions. They do not
5030 have a prototype and thus no TYPE_ARG_TYPES. */
5031 for (t = DECL_ARGUMENTS (decl); t; t = TREE_CHAIN (t))
5034 /* Check if the function has variadic arguments. */
5035 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5036 if (TREE_VALUE (t) == void_type_node)
5044 /* Creation function node for DECL, using NAME, and return the index
5045 of the variable we've created for the function. */
5048 create_function_info_for (tree decl, const char *name)
5050 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5051 varinfo_t vi, prev_vi;
5054 bool is_varargs = false;
5055 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5057 /* Create the variable info. */
5059 vi = new_var_info (decl, name);
5062 vi->fullsize = fi_parm_base + num_args;
5064 vi->may_have_pointers = false;
5067 insert_vi_for_tree (vi->decl, vi);
5071 /* Create a variable for things the function clobbers and one for
5072 things the function uses. */
5074 varinfo_t clobbervi, usevi;
5075 const char *newname;
5078 asprintf (&tempname, "%s.clobber", name);
5079 newname = ggc_strdup (tempname);
5082 clobbervi = new_var_info (NULL, newname);
5083 clobbervi->offset = fi_clobbers;
5084 clobbervi->size = 1;
5085 clobbervi->fullsize = vi->fullsize;
5086 clobbervi->is_full_var = true;
5087 clobbervi->is_global_var = false;
5088 gcc_assert (prev_vi->offset < clobbervi->offset);
5089 prev_vi->next = clobbervi;
5090 prev_vi = clobbervi;
5093 asprintf (&tempname, "%s.use", name);
5094 newname = ggc_strdup (tempname);
5097 usevi = new_var_info (NULL, newname);
5098 usevi->offset = fi_uses;
5100 usevi->fullsize = vi->fullsize;
5101 usevi->is_full_var = true;
5102 usevi->is_global_var = false;
5103 gcc_assert (prev_vi->offset < usevi->offset);
5104 prev_vi->next = usevi;
5109 /* And one for the static chain. */
5110 if (fn->static_chain_decl != NULL_TREE)
5113 const char *newname;
5116 asprintf (&tempname, "%s.chain", name);
5117 newname = ggc_strdup (tempname);
5120 chainvi = new_var_info (fn->static_chain_decl, newname);
5121 chainvi->offset = fi_static_chain;
5123 chainvi->fullsize = vi->fullsize;
5124 chainvi->is_full_var = true;
5125 chainvi->is_global_var = false;
5126 gcc_assert (prev_vi->offset < chainvi->offset);
5127 prev_vi->next = chainvi;
5130 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5133 /* Create a variable for the return var. */
5134 if (DECL_RESULT (decl) != NULL
5135 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5138 const char *newname;
5140 tree resultdecl = decl;
5142 if (DECL_RESULT (decl))
5143 resultdecl = DECL_RESULT (decl);
5145 asprintf (&tempname, "%s.result", name);
5146 newname = ggc_strdup (tempname);
5149 resultvi = new_var_info (resultdecl, newname);
5150 resultvi->offset = fi_result;
5152 resultvi->fullsize = vi->fullsize;
5153 resultvi->is_full_var = true;
5154 if (DECL_RESULT (decl))
5155 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5156 gcc_assert (prev_vi->offset < resultvi->offset);
5157 prev_vi->next = resultvi;
5160 if (DECL_RESULT (decl))
5161 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5164 /* Set up variables for each argument. */
5165 arg = DECL_ARGUMENTS (decl);
5166 for (i = 0; i < num_args; i++)
5169 const char *newname;
5171 tree argdecl = decl;
5176 asprintf (&tempname, "%s.arg%d", name, i);
5177 newname = ggc_strdup (tempname);
5180 argvi = new_var_info (argdecl, newname);
5181 argvi->offset = fi_parm_base + i;
5183 argvi->is_full_var = true;
5184 argvi->fullsize = vi->fullsize;
5186 argvi->may_have_pointers = could_have_pointers (arg);
5187 gcc_assert (prev_vi->offset < argvi->offset);
5188 prev_vi->next = argvi;
5193 insert_vi_for_tree (arg, argvi);
5194 arg = TREE_CHAIN (arg);
5198 /* Add one representative for all further args. */
5202 const char *newname;
5206 asprintf (&tempname, "%s.varargs", name);
5207 newname = ggc_strdup (tempname);
5210 /* We need sth that can be pointed to for va_start. */
5211 decl = create_tmp_var_raw (ptr_type_node, name);
5214 argvi = new_var_info (decl, newname);
5215 argvi->offset = fi_parm_base + num_args;
5217 argvi->is_full_var = true;
5218 argvi->is_heap_var = true;
5219 argvi->fullsize = vi->fullsize;
5220 gcc_assert (prev_vi->offset < argvi->offset);
5221 prev_vi->next = argvi;
5230 /* Return true if FIELDSTACK contains fields that overlap.
5231 FIELDSTACK is assumed to be sorted by offset. */
5234 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5236 fieldoff_s *fo = NULL;
5238 HOST_WIDE_INT lastoffset = -1;
5240 for (i = 0; VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5242 if (fo->offset == lastoffset)
5244 lastoffset = fo->offset;
5249 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5250 This will also create any varinfo structures necessary for fields
5254 create_variable_info_for_1 (tree decl, const char *name)
5256 varinfo_t vi, newvi;
5257 tree decl_type = TREE_TYPE (decl);
5258 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5259 VEC (fieldoff_s,heap) *fieldstack = NULL;
5264 || !host_integerp (declsize, 1))
5266 vi = new_var_info (decl, name);
5272 vi->fullsize = TREE_INT_CST_LOW (declsize);
5273 vi->size = vi->fullsize;
5276 insert_vi_for_tree (vi->decl, vi);
5278 /* ??? The setting of vi->may_have_pointers is too conservative here
5279 and may get refined below. Thus we have superfluous constraints
5280 here sometimes which triggers the commented assert in
5281 dump_sa_points_to_info. */
5282 if (vi->is_global_var
5283 && vi->may_have_pointers)
5285 /* Mark global restrict qualified pointers. */
5286 if (POINTER_TYPE_P (TREE_TYPE (decl))
5287 && TYPE_RESTRICT (TREE_TYPE (decl)))
5288 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5290 /* For escaped variables initialize them from nonlocal. */
5292 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5293 make_copy_constraint (vi, nonlocal_id);
5295 /* If this is a global variable with an initializer and we are in
5296 IPA mode generate constraints for it. In non-IPA mode
5297 the initializer from nonlocal is all we need. */
5299 && DECL_INITIAL (vi->decl))
5301 VEC (ce_s, heap) *rhsc = NULL;
5302 struct constraint_expr lhs, *rhsp;
5304 get_constraint_for (DECL_INITIAL (vi->decl), &rhsc);
5308 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5309 process_constraint (new_constraint (lhs, *rhsp));
5310 /* If this is a variable that escapes from the unit
5311 the initializer escapes as well. */
5312 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5314 lhs.var = escaped_id;
5317 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5318 process_constraint (new_constraint (lhs, *rhsp));
5320 VEC_free (ce_s, heap, rhsc);
5321 /* ??? Force us to not use subfields. Else we'd have to parse
5322 arbitrary initializers. */
5323 VEC_free (fieldoff_s, heap, fieldstack);
5327 /* Collect field information. */
5328 if (use_field_sensitive
5329 && var_can_have_subvars (decl)
5330 /* ??? Force us to not use subfields for global initializers
5331 in IPA mode. Else we'd have to parse arbitrary initializers. */
5333 && is_global_var (decl)
5334 && DECL_INITIAL (decl)))
5336 fieldoff_s *fo = NULL;
5337 bool notokay = false;
5340 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5342 || DECL_EXTERNAL (decl)
5343 || TREE_ADDRESSABLE (decl));
5345 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5346 if (fo->has_unknown_size
5353 /* We can't sort them if we have a field with a variable sized type,
5354 which will make notokay = true. In that case, we are going to return
5355 without creating varinfos for the fields anyway, so sorting them is a
5359 sort_fieldstack (fieldstack);
5360 /* Due to some C++ FE issues, like PR 22488, we might end up
5361 what appear to be overlapping fields even though they,
5362 in reality, do not overlap. Until the C++ FE is fixed,
5363 we will simply disable field-sensitivity for these cases. */
5364 notokay = check_for_overlaps (fieldstack);
5368 VEC_free (fieldoff_s, heap, fieldstack);
5371 /* If we didn't end up collecting sub-variables create a full
5372 variable for the decl. */
5373 if (VEC_length (fieldoff_s, fieldstack) <= 1
5374 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5376 vi = new_var_info (decl, name);
5378 vi->may_have_pointers = could_have_pointers (decl);
5379 vi->fullsize = TREE_INT_CST_LOW (declsize);
5380 vi->size = vi->fullsize;
5381 vi->is_full_var = true;
5382 VEC_free (fieldoff_s, heap, fieldstack);
5386 vi = new_var_info (decl, name);
5387 vi->fullsize = TREE_INT_CST_LOW (declsize);
5388 for (i = 0, newvi = vi;
5389 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5390 ++i, newvi = newvi->next)
5392 const char *newname = "NULL";
5395 vi->offset = fo->offset;
5396 vi->may_have_pointers = fo->may_have_pointers;
5397 if (vi->is_global_var
5398 && vi->may_have_pointers)
5400 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5401 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5402 newname = ggc_strdup (tempname);
5405 newvi->name = newname;
5406 newvi->offset = fo->offset;
5407 newvi->size = fo->size;
5408 newvi->fullsize = vi->fullsize;
5409 newvi->may_have_pointers = fo->may_have_pointers;
5410 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5411 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5412 newvi->next = new_var_info (decl, name);
5415 VEC_free (fieldoff_s, heap, fieldstack);
5421 create_variable_info_for (tree decl, const char *name)
5423 varinfo_t vi = create_variable_info_for_1 (decl, name);
5424 unsigned int id = vi->id;
5426 insert_vi_for_tree (decl, vi);
5428 /* Create initial constraints for globals. */
5429 for (; vi; vi = vi->next)
5431 if (!vi->may_have_pointers
5432 || !vi->is_global_var)
5435 /* Mark global restrict qualified pointers. */
5436 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5437 && TYPE_RESTRICT (TREE_TYPE (decl)))
5438 || vi->only_restrict_pointers)
5439 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5441 /* For escaped variables initialize them from nonlocal. */
5443 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5444 make_copy_constraint (vi, nonlocal_id);
5446 /* If this is a global variable with an initializer and we are in
5447 IPA mode generate constraints for it. In non-IPA mode
5448 the initializer from nonlocal is all we need. */
5450 && DECL_INITIAL (decl))
5452 VEC (ce_s, heap) *rhsc = NULL;
5453 struct constraint_expr lhs, *rhsp;
5455 get_constraint_for (DECL_INITIAL (decl), &rhsc);
5459 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5460 process_constraint (new_constraint (lhs, *rhsp));
5461 /* If this is a variable that escapes from the unit
5462 the initializer escapes as well. */
5463 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5465 lhs.var = escaped_id;
5468 for (i = 0; VEC_iterate (ce_s, rhsc, i, rhsp); ++i)
5469 process_constraint (new_constraint (lhs, *rhsp));
5471 VEC_free (ce_s, heap, rhsc);
5478 /* Print out the points-to solution for VAR to FILE. */
5481 dump_solution_for_var (FILE *file, unsigned int var)
5483 varinfo_t vi = get_varinfo (var);
5487 /* Dump the solution for unified vars anyway, this avoids difficulties
5488 in scanning dumps in the testsuite. */
5489 fprintf (file, "%s = { ", vi->name);
5490 vi = get_varinfo (find (var));
5491 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5492 fprintf (file, "%s ", get_varinfo (i)->name);
5493 fprintf (file, "}");
5495 /* But note when the variable was unified. */
5497 fprintf (file, " same as %s", vi->name);
5499 fprintf (file, "\n");
5502 /* Print the points-to solution for VAR to stdout. */
5505 debug_solution_for_var (unsigned int var)
5507 dump_solution_for_var (stdout, var);
5510 /* Create varinfo structures for all of the variables in the
5511 function for intraprocedural mode. */
5514 intra_create_variable_infos (void)
5518 /* For each incoming pointer argument arg, create the constraint ARG
5519 = NONLOCAL or a dummy variable if it is a restrict qualified
5520 passed-by-reference argument. */
5521 for (t = DECL_ARGUMENTS (current_function_decl); t; t = TREE_CHAIN (t))
5525 if (!could_have_pointers (t))
5528 /* For restrict qualified pointers to objects passed by
5529 reference build a real representative for the pointed-to object. */
5530 if (DECL_BY_REFERENCE (t)
5531 && POINTER_TYPE_P (TREE_TYPE (t))
5532 && TYPE_RESTRICT (TREE_TYPE (t)))
5534 struct constraint_expr lhsc, rhsc;
5536 tree heapvar = heapvar_lookup (t, 0);
5537 if (heapvar == NULL_TREE)
5540 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5542 DECL_EXTERNAL (heapvar) = 1;
5543 heapvar_insert (t, 0, heapvar);
5544 ann = get_var_ann (heapvar);
5545 ann->is_heapvar = 1;
5547 if (gimple_referenced_vars (cfun))
5548 add_referenced_var (heapvar);
5549 lhsc.var = get_vi_for_tree (t)->id;
5552 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5553 rhsc.type = ADDRESSOF;
5555 process_constraint (new_constraint (lhsc, rhsc));
5556 vi->is_restrict_var = 1;
5560 for (p = get_vi_for_tree (t); p; p = p->next)
5562 if (p->may_have_pointers)
5563 make_constraint_from (p, nonlocal_id);
5564 if (p->only_restrict_pointers)
5565 make_constraint_from_restrict (p, "PARM_RESTRICT");
5567 if (POINTER_TYPE_P (TREE_TYPE (t))
5568 && TYPE_RESTRICT (TREE_TYPE (t)))
5569 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5572 /* Add a constraint for a result decl that is passed by reference. */
5573 if (DECL_RESULT (cfun->decl)
5574 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5576 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5578 for (p = result_vi; p; p = p->next)
5579 make_constraint_from (p, nonlocal_id);
5582 /* Add a constraint for the incoming static chain parameter. */
5583 if (cfun->static_chain_decl != NULL_TREE)
5585 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5587 for (p = chain_vi; p; p = p->next)
5588 make_constraint_from (p, nonlocal_id);
5592 /* Structure used to put solution bitmaps in a hashtable so they can
5593 be shared among variables with the same points-to set. */
5595 typedef struct shared_bitmap_info
5599 } *shared_bitmap_info_t;
5600 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5602 static htab_t shared_bitmap_table;
5604 /* Hash function for a shared_bitmap_info_t */
5607 shared_bitmap_hash (const void *p)
5609 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5610 return bi->hashcode;
5613 /* Equality function for two shared_bitmap_info_t's. */
5616 shared_bitmap_eq (const void *p1, const void *p2)
5618 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5619 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5620 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5623 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5624 existing instance if there is one, NULL otherwise. */
5627 shared_bitmap_lookup (bitmap pt_vars)
5630 struct shared_bitmap_info sbi;
5632 sbi.pt_vars = pt_vars;
5633 sbi.hashcode = bitmap_hash (pt_vars);
5635 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5636 sbi.hashcode, NO_INSERT);
5640 return ((shared_bitmap_info_t) *slot)->pt_vars;
5644 /* Add a bitmap to the shared bitmap hashtable. */
5647 shared_bitmap_add (bitmap pt_vars)
5650 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5652 sbi->pt_vars = pt_vars;
5653 sbi->hashcode = bitmap_hash (pt_vars);
5655 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5656 sbi->hashcode, INSERT);
5657 gcc_assert (!*slot);
5658 *slot = (void *) sbi;
5662 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5665 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5670 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5672 varinfo_t vi = get_varinfo (i);
5674 /* The only artificial variables that are allowed in a may-alias
5675 set are heap variables. */
5676 if (vi->is_artificial_var && !vi->is_heap_var)
5679 if (TREE_CODE (vi->decl) == VAR_DECL
5680 || TREE_CODE (vi->decl) == PARM_DECL
5681 || TREE_CODE (vi->decl) == RESULT_DECL)
5683 /* If we are in IPA mode we will not recompute points-to
5684 sets after inlining so make sure they stay valid. */
5686 && !DECL_PT_UID_SET_P (vi->decl))
5687 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5689 /* Add the decl to the points-to set. Note that the points-to
5690 set contains global variables. */
5691 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5692 if (vi->is_global_var)
5693 pt->vars_contains_global = true;
5699 /* Compute the points-to solution *PT for the variable VI. */
5702 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5706 bitmap finished_solution;
5710 memset (pt, 0, sizeof (struct pt_solution));
5712 /* This variable may have been collapsed, let's get the real
5714 vi = get_varinfo (find (orig_vi->id));
5716 /* Translate artificial variables into SSA_NAME_PTR_INFO
5718 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5720 varinfo_t vi = get_varinfo (i);
5722 if (vi->is_artificial_var)
5724 if (vi->id == nothing_id)
5726 else if (vi->id == escaped_id)
5729 pt->ipa_escaped = 1;
5733 else if (vi->id == nonlocal_id)
5735 else if (vi->is_heap_var)
5736 /* We represent heapvars in the points-to set properly. */
5738 else if (vi->id == readonly_id)
5741 else if (vi->id == anything_id
5742 || vi->id == integer_id)
5745 if (vi->is_restrict_var)
5746 pt->vars_contains_restrict = true;
5749 /* Instead of doing extra work, simply do not create
5750 elaborate points-to information for pt_anything pointers. */
5752 && (orig_vi->is_artificial_var
5753 || !pt->vars_contains_restrict))
5756 /* Share the final set of variables when possible. */
5757 finished_solution = BITMAP_GGC_ALLOC ();
5758 stats.points_to_sets_created++;
5760 set_uids_in_ptset (finished_solution, vi->solution, pt);
5761 result = shared_bitmap_lookup (finished_solution);
5764 shared_bitmap_add (finished_solution);
5765 pt->vars = finished_solution;
5770 bitmap_clear (finished_solution);
5774 /* Given a pointer variable P, fill in its points-to set. */
5777 find_what_p_points_to (tree p)
5779 struct ptr_info_def *pi;
5783 /* For parameters, get at the points-to set for the actual parm
5785 if (TREE_CODE (p) == SSA_NAME
5786 && TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5787 && SSA_NAME_IS_DEFAULT_DEF (p))
5788 lookup_p = SSA_NAME_VAR (p);
5790 vi = lookup_vi_for_tree (lookup_p);
5794 pi = get_ptr_info (p);
5795 find_what_var_points_to (vi, &pi->pt);
5799 /* Query statistics for points-to solutions. */
5802 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5803 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5804 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5805 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5809 dump_pta_stats (FILE *s)
5811 fprintf (s, "\nPTA query stats:\n");
5812 fprintf (s, " pt_solution_includes: "
5813 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5814 HOST_WIDE_INT_PRINT_DEC" queries\n",
5815 pta_stats.pt_solution_includes_no_alias,
5816 pta_stats.pt_solution_includes_no_alias
5817 + pta_stats.pt_solution_includes_may_alias);
5818 fprintf (s, " pt_solutions_intersect: "
5819 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5820 HOST_WIDE_INT_PRINT_DEC" queries\n",
5821 pta_stats.pt_solutions_intersect_no_alias,
5822 pta_stats.pt_solutions_intersect_no_alias
5823 + pta_stats.pt_solutions_intersect_may_alias);
5827 /* Reset the points-to solution *PT to a conservative default
5828 (point to anything). */
5831 pt_solution_reset (struct pt_solution *pt)
5833 memset (pt, 0, sizeof (struct pt_solution));
5834 pt->anything = true;
5837 /* Set the points-to solution *PT to point only to the variables
5838 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5839 global variables and VARS_CONTAINS_RESTRICT specifies whether
5840 it contains restrict tag variables. */
5843 pt_solution_set (struct pt_solution *pt, bitmap vars,
5844 bool vars_contains_global, bool vars_contains_restrict)
5846 memset (pt, 0, sizeof (struct pt_solution));
5848 pt->vars_contains_global = vars_contains_global;
5849 pt->vars_contains_restrict = vars_contains_restrict;
5852 /* Computes the union of the points-to solutions *DEST and *SRC and
5853 stores the result in *DEST. This changes the points-to bitmap
5854 of *DEST and thus may not be used if that might be shared.
5855 The points-to bitmap of *SRC and *DEST will not be shared after
5856 this function if they were not before. */
5859 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5861 dest->anything |= src->anything;
5864 pt_solution_reset (dest);
5868 dest->nonlocal |= src->nonlocal;
5869 dest->escaped |= src->escaped;
5870 dest->ipa_escaped |= src->ipa_escaped;
5871 dest->null |= src->null;
5872 dest->vars_contains_global |= src->vars_contains_global;
5873 dest->vars_contains_restrict |= src->vars_contains_restrict;
5878 dest->vars = BITMAP_GGC_ALLOC ();
5879 bitmap_ior_into (dest->vars, src->vars);
5882 /* Return true if the points-to solution *PT is empty. */
5885 pt_solution_empty_p (struct pt_solution *pt)
5892 && !bitmap_empty_p (pt->vars))
5895 /* If the solution includes ESCAPED, check if that is empty. */
5897 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5900 /* If the solution includes ESCAPED, check if that is empty. */
5902 && !pt_solution_empty_p (&ipa_escaped_pt))
5908 /* Return true if the points-to solution *PT includes global memory. */
5911 pt_solution_includes_global (struct pt_solution *pt)
5915 || pt->vars_contains_global)
5919 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5921 if (pt->ipa_escaped)
5922 return pt_solution_includes_global (&ipa_escaped_pt);
5924 /* ??? This predicate is not correct for the IPA-PTA solution
5925 as we do not properly distinguish between unit escape points
5926 and global variables. */
5927 if (cfun->gimple_df->ipa_pta)
5933 /* Return true if the points-to solution *PT includes the variable
5934 declaration DECL. */
5937 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5943 && is_global_var (decl))
5947 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5950 /* If the solution includes ESCAPED, check it. */
5952 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5955 /* If the solution includes ESCAPED, check it. */
5957 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5964 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5966 bool res = pt_solution_includes_1 (pt, decl);
5968 ++pta_stats.pt_solution_includes_may_alias;
5970 ++pta_stats.pt_solution_includes_no_alias;
5974 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5978 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5980 if (pt1->anything || pt2->anything)
5983 /* If either points to unknown global memory and the other points to
5984 any global memory they alias. */
5987 || pt2->vars_contains_global))
5989 && pt1->vars_contains_global))
5992 /* Check the escaped solution if required. */
5993 if ((pt1->escaped || pt2->escaped)
5994 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5996 /* If both point to escaped memory and that solution
5997 is not empty they alias. */
5998 if (pt1->escaped && pt2->escaped)
6001 /* If either points to escaped memory see if the escaped solution
6002 intersects with the other. */
6004 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6006 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6010 /* Check the escaped solution if required.
6011 ??? Do we need to check the local against the IPA escaped sets? */
6012 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6013 && !pt_solution_empty_p (&ipa_escaped_pt))
6015 /* If both point to escaped memory and that solution
6016 is not empty they alias. */
6017 if (pt1->ipa_escaped && pt2->ipa_escaped)
6020 /* If either points to escaped memory see if the escaped solution
6021 intersects with the other. */
6022 if ((pt1->ipa_escaped
6023 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6024 || (pt2->ipa_escaped
6025 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6029 /* Now both pointers alias if their points-to solution intersects. */
6032 && bitmap_intersect_p (pt1->vars, pt2->vars));
6036 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6038 bool res = pt_solutions_intersect_1 (pt1, pt2);
6040 ++pta_stats.pt_solutions_intersect_may_alias;
6042 ++pta_stats.pt_solutions_intersect_no_alias;
6046 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6047 qualified pointers are possibly based on the same pointer. */
6050 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6051 struct pt_solution *pt2)
6053 /* If we deal with points-to solutions of two restrict qualified
6054 pointers solely rely on the pointed-to variable bitmap intersection.
6055 For two pointers that are based on each other the bitmaps will
6057 if (pt1->vars_contains_restrict
6058 && pt2->vars_contains_restrict)
6060 gcc_assert (pt1->vars && pt2->vars);
6061 return bitmap_intersect_p (pt1->vars, pt2->vars);
6068 /* Dump points-to information to OUTFILE. */
6071 dump_sa_points_to_info (FILE *outfile)
6075 fprintf (outfile, "\nPoints-to sets\n\n");
6077 if (dump_flags & TDF_STATS)
6079 fprintf (outfile, "Stats:\n");
6080 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6081 fprintf (outfile, "Non-pointer vars: %d\n",
6082 stats.nonpointer_vars);
6083 fprintf (outfile, "Statically unified vars: %d\n",
6084 stats.unified_vars_static);
6085 fprintf (outfile, "Dynamically unified vars: %d\n",
6086 stats.unified_vars_dynamic);
6087 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6088 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6089 fprintf (outfile, "Number of implicit edges: %d\n",
6090 stats.num_implicit_edges);
6093 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6095 varinfo_t vi = get_varinfo (i);
6096 if (!vi->may_have_pointers)
6098 gcc_assert (find (i) == i
6099 || !(vi = get_varinfo (find (i)))->may_have_pointers);
6100 /* ??? See create_variable_info_for.
6101 gcc_assert (bitmap_empty_p (vi->solution)); */
6104 dump_solution_for_var (outfile, i);
6109 /* Debug points-to information to stderr. */
6112 debug_sa_points_to_info (void)
6114 dump_sa_points_to_info (stderr);
6118 /* Initialize the always-existing constraint variables for NULL
6119 ANYTHING, READONLY, and INTEGER */
6122 init_base_vars (void)
6124 struct constraint_expr lhs, rhs;
6125 varinfo_t var_anything;
6126 varinfo_t var_nothing;
6127 varinfo_t var_readonly;
6128 varinfo_t var_escaped;
6129 varinfo_t var_nonlocal;
6130 varinfo_t var_storedanything;
6131 varinfo_t var_integer;
6133 /* Create the NULL variable, used to represent that a variable points
6135 var_nothing = new_var_info (NULL_TREE, "NULL");
6136 gcc_assert (var_nothing->id == nothing_id);
6137 var_nothing->is_artificial_var = 1;
6138 var_nothing->offset = 0;
6139 var_nothing->size = ~0;
6140 var_nothing->fullsize = ~0;
6141 var_nothing->is_special_var = 1;
6142 var_nothing->may_have_pointers = 0;
6143 var_nothing->is_global_var = 0;
6145 /* Create the ANYTHING variable, used to represent that a variable
6146 points to some unknown piece of memory. */
6147 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6148 gcc_assert (var_anything->id == anything_id);
6149 var_anything->is_artificial_var = 1;
6150 var_anything->size = ~0;
6151 var_anything->offset = 0;
6152 var_anything->next = NULL;
6153 var_anything->fullsize = ~0;
6154 var_anything->is_special_var = 1;
6156 /* Anything points to anything. This makes deref constraints just
6157 work in the presence of linked list and other p = *p type loops,
6158 by saying that *ANYTHING = ANYTHING. */
6160 lhs.var = anything_id;
6162 rhs.type = ADDRESSOF;
6163 rhs.var = anything_id;
6166 /* This specifically does not use process_constraint because
6167 process_constraint ignores all anything = anything constraints, since all
6168 but this one are redundant. */
6169 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6171 /* Create the READONLY variable, used to represent that a variable
6172 points to readonly memory. */
6173 var_readonly = new_var_info (NULL_TREE, "READONLY");
6174 gcc_assert (var_readonly->id == readonly_id);
6175 var_readonly->is_artificial_var = 1;
6176 var_readonly->offset = 0;
6177 var_readonly->size = ~0;
6178 var_readonly->fullsize = ~0;
6179 var_readonly->next = NULL;
6180 var_readonly->is_special_var = 1;
6182 /* readonly memory points to anything, in order to make deref
6183 easier. In reality, it points to anything the particular
6184 readonly variable can point to, but we don't track this
6187 lhs.var = readonly_id;
6189 rhs.type = ADDRESSOF;
6190 rhs.var = readonly_id; /* FIXME */
6192 process_constraint (new_constraint (lhs, rhs));
6194 /* Create the ESCAPED variable, used to represent the set of escaped
6196 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6197 gcc_assert (var_escaped->id == escaped_id);
6198 var_escaped->is_artificial_var = 1;
6199 var_escaped->offset = 0;
6200 var_escaped->size = ~0;
6201 var_escaped->fullsize = ~0;
6202 var_escaped->is_special_var = 0;
6204 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6206 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6207 gcc_assert (var_nonlocal->id == nonlocal_id);
6208 var_nonlocal->is_artificial_var = 1;
6209 var_nonlocal->offset = 0;
6210 var_nonlocal->size = ~0;
6211 var_nonlocal->fullsize = ~0;
6212 var_nonlocal->is_special_var = 1;
6214 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6216 lhs.var = escaped_id;
6219 rhs.var = escaped_id;
6221 process_constraint (new_constraint (lhs, rhs));
6223 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6224 whole variable escapes. */
6226 lhs.var = escaped_id;
6229 rhs.var = escaped_id;
6230 rhs.offset = UNKNOWN_OFFSET;
6231 process_constraint (new_constraint (lhs, rhs));
6233 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6234 everything pointed to by escaped points to what global memory can
6237 lhs.var = escaped_id;
6240 rhs.var = nonlocal_id;
6242 process_constraint (new_constraint (lhs, rhs));
6244 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6245 global memory may point to global memory and escaped memory. */
6247 lhs.var = nonlocal_id;
6249 rhs.type = ADDRESSOF;
6250 rhs.var = nonlocal_id;
6252 process_constraint (new_constraint (lhs, rhs));
6253 rhs.type = ADDRESSOF;
6254 rhs.var = escaped_id;
6256 process_constraint (new_constraint (lhs, rhs));
6258 /* Create the STOREDANYTHING variable, used to represent the set of
6259 variables stored to *ANYTHING. */
6260 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6261 gcc_assert (var_storedanything->id == storedanything_id);
6262 var_storedanything->is_artificial_var = 1;
6263 var_storedanything->offset = 0;
6264 var_storedanything->size = ~0;
6265 var_storedanything->fullsize = ~0;
6266 var_storedanything->is_special_var = 0;
6268 /* Create the INTEGER variable, used to represent that a variable points
6269 to what an INTEGER "points to". */
6270 var_integer = new_var_info (NULL_TREE, "INTEGER");
6271 gcc_assert (var_integer->id == integer_id);
6272 var_integer->is_artificial_var = 1;
6273 var_integer->size = ~0;
6274 var_integer->fullsize = ~0;
6275 var_integer->offset = 0;
6276 var_integer->next = NULL;
6277 var_integer->is_special_var = 1;
6279 /* INTEGER = ANYTHING, because we don't know where a dereference of
6280 a random integer will point to. */
6282 lhs.var = integer_id;
6284 rhs.type = ADDRESSOF;
6285 rhs.var = anything_id;
6287 process_constraint (new_constraint (lhs, rhs));
6290 /* Initialize things necessary to perform PTA */
6293 init_alias_vars (void)
6295 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6297 bitmap_obstack_initialize (&pta_obstack);
6298 bitmap_obstack_initialize (&oldpta_obstack);
6299 bitmap_obstack_initialize (&predbitmap_obstack);
6301 constraint_pool = create_alloc_pool ("Constraint pool",
6302 sizeof (struct constraint), 30);
6303 variable_info_pool = create_alloc_pool ("Variable info pool",
6304 sizeof (struct variable_info), 30);
6305 constraints = VEC_alloc (constraint_t, heap, 8);
6306 varmap = VEC_alloc (varinfo_t, heap, 8);
6307 vi_for_tree = pointer_map_create ();
6308 call_stmt_vars = pointer_map_create ();
6310 memset (&stats, 0, sizeof (stats));
6311 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6312 shared_bitmap_eq, free);
6316 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6317 predecessor edges. */
6320 remove_preds_and_fake_succs (constraint_graph_t graph)
6324 /* Clear the implicit ref and address nodes from the successor
6326 for (i = 0; i < FIRST_REF_NODE; i++)
6328 if (graph->succs[i])
6329 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6330 FIRST_REF_NODE * 2);
6333 /* Free the successor list for the non-ref nodes. */
6334 for (i = FIRST_REF_NODE; i < graph->size; i++)
6336 if (graph->succs[i])
6337 BITMAP_FREE (graph->succs[i]);
6340 /* Now reallocate the size of the successor list as, and blow away
6341 the predecessor bitmaps. */
6342 graph->size = VEC_length (varinfo_t, varmap);
6343 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6345 free (graph->implicit_preds);
6346 graph->implicit_preds = NULL;
6347 free (graph->preds);
6348 graph->preds = NULL;
6349 bitmap_obstack_release (&predbitmap_obstack);
6352 /* Initialize the heapvar for statement mapping. */
6355 init_alias_heapvars (void)
6357 if (!heapvar_for_stmt)
6358 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6362 /* Delete the heapvar for statement mapping. */
6365 delete_alias_heapvars (void)
6367 if (heapvar_for_stmt)
6368 htab_delete (heapvar_for_stmt);
6369 heapvar_for_stmt = NULL;
6372 /* Solve the constraint set. */
6375 solve_constraints (void)
6377 struct scc_info *si;
6381 "\nCollapsing static cycles and doing variable "
6384 init_graph (VEC_length (varinfo_t, varmap) * 2);
6387 fprintf (dump_file, "Building predecessor graph\n");
6388 build_pred_graph ();
6391 fprintf (dump_file, "Detecting pointer and location "
6393 si = perform_var_substitution (graph);
6396 fprintf (dump_file, "Rewriting constraints and unifying "
6398 rewrite_constraints (graph, si);
6400 build_succ_graph ();
6401 free_var_substitution_info (si);
6403 if (dump_file && (dump_flags & TDF_GRAPH))
6404 dump_constraint_graph (dump_file);
6406 move_complex_constraints (graph);
6409 fprintf (dump_file, "Uniting pointer but not location equivalent "
6411 unite_pointer_equivalences (graph);
6414 fprintf (dump_file, "Finding indirect cycles\n");
6415 find_indirect_cycles (graph);
6417 /* Implicit nodes and predecessors are no longer necessary at this
6419 remove_preds_and_fake_succs (graph);
6422 fprintf (dump_file, "Solving graph\n");
6424 solve_graph (graph);
6427 dump_sa_points_to_info (dump_file);
6430 /* Create points-to sets for the current function. See the comments
6431 at the start of the file for an algorithmic overview. */
6434 compute_points_to_sets (void)
6440 timevar_push (TV_TREE_PTA);
6443 init_alias_heapvars ();
6445 intra_create_variable_infos ();
6447 /* Now walk all statements and build the constraint set. */
6450 gimple_stmt_iterator gsi;
6452 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6454 gimple phi = gsi_stmt (gsi);
6456 if (is_gimple_reg (gimple_phi_result (phi)))
6457 find_func_aliases (phi);
6460 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6462 gimple stmt = gsi_stmt (gsi);
6464 find_func_aliases (stmt);
6470 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6471 dump_constraints (dump_file, 0);
6474 /* From the constraints compute the points-to sets. */
6475 solve_constraints ();
6477 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6478 find_what_var_points_to (get_varinfo (escaped_id),
6479 &cfun->gimple_df->escaped);
6481 /* Make sure the ESCAPED solution (which is used as placeholder in
6482 other solutions) does not reference itself. This simplifies
6483 points-to solution queries. */
6484 cfun->gimple_df->escaped.escaped = 0;
6486 /* Mark escaped HEAP variables as global. */
6487 for (i = 0; VEC_iterate (varinfo_t, varmap, i, vi); ++i)
6489 && !vi->is_restrict_var
6490 && !vi->is_global_var)
6491 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6492 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6494 /* Compute the points-to sets for pointer SSA_NAMEs. */
6495 for (i = 0; i < num_ssa_names; ++i)
6497 tree ptr = ssa_name (i);
6499 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6500 find_what_p_points_to (ptr);
6503 /* Compute the call-used/clobbered sets. */
6506 gimple_stmt_iterator gsi;
6508 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6510 gimple stmt = gsi_stmt (gsi);
6511 struct pt_solution *pt;
6512 if (!is_gimple_call (stmt))
6515 pt = gimple_call_use_set (stmt);
6516 if (gimple_call_flags (stmt) & ECF_CONST)
6517 memset (pt, 0, sizeof (struct pt_solution));
6518 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6520 find_what_var_points_to (vi, pt);
6521 /* Escaped (and thus nonlocal) variables are always
6522 implicitly used by calls. */
6523 /* ??? ESCAPED can be empty even though NONLOCAL
6530 /* If there is nothing special about this call then
6531 we have made everything that is used also escape. */
6532 *pt = cfun->gimple_df->escaped;
6536 pt = gimple_call_clobber_set (stmt);
6537 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6538 memset (pt, 0, sizeof (struct pt_solution));
6539 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6541 find_what_var_points_to (vi, pt);
6542 /* Escaped (and thus nonlocal) variables are always
6543 implicitly clobbered by calls. */
6544 /* ??? ESCAPED can be empty even though NONLOCAL
6551 /* If there is nothing special about this call then
6552 we have made everything that is used also escape. */
6553 *pt = cfun->gimple_df->escaped;
6559 timevar_pop (TV_TREE_PTA);
6563 /* Delete created points-to sets. */
6566 delete_points_to_sets (void)
6570 htab_delete (shared_bitmap_table);
6571 if (dump_file && (dump_flags & TDF_STATS))
6572 fprintf (dump_file, "Points to sets created:%d\n",
6573 stats.points_to_sets_created);
6575 pointer_map_destroy (vi_for_tree);
6576 pointer_map_destroy (call_stmt_vars);
6577 bitmap_obstack_release (&pta_obstack);
6578 VEC_free (constraint_t, heap, constraints);
6580 for (i = 0; i < graph->size; i++)
6581 VEC_free (constraint_t, heap, graph->complex[i]);
6582 free (graph->complex);
6585 free (graph->succs);
6587 free (graph->pe_rep);
6588 free (graph->indirect_cycles);
6591 VEC_free (varinfo_t, heap, varmap);
6592 free_alloc_pool (variable_info_pool);
6593 free_alloc_pool (constraint_pool);
6597 /* Compute points-to information for every SSA_NAME pointer in the
6598 current function and compute the transitive closure of escaped
6599 variables to re-initialize the call-clobber states of local variables. */
6602 compute_may_aliases (void)
6604 if (cfun->gimple_df->ipa_pta)
6608 fprintf (dump_file, "\nNot re-computing points-to information "
6609 "because IPA points-to information is available.\n\n");
6611 /* But still dump what we have remaining it. */
6612 dump_alias_info (dump_file);
6614 if (dump_flags & TDF_DETAILS)
6615 dump_referenced_vars (dump_file);
6621 /* For each pointer P_i, determine the sets of variables that P_i may
6622 point-to. Compute the reachability set of escaped and call-used
6624 compute_points_to_sets ();
6626 /* Debugging dumps. */
6629 dump_alias_info (dump_file);
6631 if (dump_flags & TDF_DETAILS)
6632 dump_referenced_vars (dump_file);
6635 /* Deallocate memory used by aliasing data structures and the internal
6636 points-to solution. */
6637 delete_points_to_sets ();
6639 gcc_assert (!need_ssa_update_p (cfun));
6645 gate_tree_pta (void)
6647 return flag_tree_pta;
6650 /* A dummy pass to cause points-to information to be computed via
6651 TODO_rebuild_alias. */
6653 struct gimple_opt_pass pass_build_alias =
6658 gate_tree_pta, /* gate */
6662 0, /* static_pass_number */
6663 TV_NONE, /* tv_id */
6664 PROP_cfg | PROP_ssa, /* properties_required */
6665 0, /* properties_provided */
6666 0, /* properties_destroyed */
6667 0, /* todo_flags_start */
6668 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6672 /* A dummy pass to cause points-to information to be computed via
6673 TODO_rebuild_alias. */
6675 struct gimple_opt_pass pass_build_ealias =
6679 "ealias", /* name */
6680 gate_tree_pta, /* gate */
6684 0, /* static_pass_number */
6685 TV_NONE, /* tv_id */
6686 PROP_cfg | PROP_ssa, /* properties_required */
6687 0, /* properties_provided */
6688 0, /* properties_destroyed */
6689 0, /* todo_flags_start */
6690 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6695 /* Return true if we should execute IPA PTA. */
6701 /* Don't bother doing anything if the program has errors. */
6702 && !(errorcount || sorrycount));
6705 /* IPA PTA solutions for ESCAPED. */
6706 struct pt_solution ipa_escaped_pt
6707 = { true, false, false, false, false, false, false, NULL };
6709 /* Execute the driver for IPA PTA. */
6711 ipa_pta_execute (void)
6713 struct cgraph_node *node;
6714 struct varpool_node *var;
6719 init_alias_heapvars ();
6722 /* Build the constraints. */
6723 for (node = cgraph_nodes; node; node = node->next)
6725 struct cgraph_node *alias;
6728 /* Nodes without a body are not interesting. Especially do not
6729 visit clones at this point for now - we get duplicate decls
6730 there for inline clones at least. */
6731 if (!gimple_has_body_p (node->decl)
6735 create_function_info_for (node->decl,
6736 cgraph_node_name (node));
6739 /* Create constraints for global variables and their initializers. */
6740 for (var = varpool_nodes; var; var = var->next)
6741 get_vi_for_tree (var->decl);
6746 "Generating constraints for global initializers\n\n");
6747 dump_constraints (dump_file, 0);
6748 fprintf (dump_file, "\n");
6750 from = VEC_length (constraint_t, constraints);
6752 for (node = cgraph_nodes; node; node = node->next)
6754 struct function *func;
6758 /* Nodes without a body are not interesting. */
6759 if (!gimple_has_body_p (node->decl)
6766 "Generating constraints for %s", cgraph_node_name (node));
6767 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6768 fprintf (dump_file, " (%s)",
6769 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6770 fprintf (dump_file, "\n");
6773 func = DECL_STRUCT_FUNCTION (node->decl);
6774 old_func_decl = current_function_decl;
6776 current_function_decl = node->decl;
6778 /* For externally visible functions use local constraints for
6779 their arguments. For local functions we see all callers
6780 and thus do not need initial constraints for parameters. */
6781 if (node->local.externally_visible)
6782 intra_create_variable_infos ();
6784 /* Build constriants for the function body. */
6785 FOR_EACH_BB_FN (bb, func)
6787 gimple_stmt_iterator gsi;
6789 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6792 gimple phi = gsi_stmt (gsi);
6794 if (is_gimple_reg (gimple_phi_result (phi)))
6795 find_func_aliases (phi);
6798 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6800 gimple stmt = gsi_stmt (gsi);
6802 find_func_aliases (stmt);
6803 find_func_clobbers (stmt);
6807 current_function_decl = old_func_decl;
6812 fprintf (dump_file, "\n");
6813 dump_constraints (dump_file, from);
6814 fprintf (dump_file, "\n");
6816 from = VEC_length (constraint_t, constraints);
6819 /* From the constraints compute the points-to sets. */
6820 solve_constraints ();
6822 /* Compute the global points-to sets for ESCAPED.
6823 ??? Note that the computed escape set is not correct
6824 for the whole unit as we fail to consider graph edges to
6825 externally visible functions. */
6826 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6828 /* Make sure the ESCAPED solution (which is used as placeholder in
6829 other solutions) does not reference itself. This simplifies
6830 points-to solution queries. */
6831 ipa_escaped_pt.ipa_escaped = 0;
6833 /* Assign the points-to sets to the SSA names in the unit. */
6834 for (node = cgraph_nodes; node; node = node->next)
6837 struct function *fn;
6841 struct pt_solution uses, clobbers;
6842 struct cgraph_edge *e;
6844 /* Nodes without a body are not interesting. */
6845 if (!gimple_has_body_p (node->decl)
6849 fn = DECL_STRUCT_FUNCTION (node->decl);
6851 /* Compute the points-to sets for pointer SSA_NAMEs. */
6852 for (i = 0; VEC_iterate (tree, fn->gimple_df->ssa_names, i, ptr); ++i)
6855 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6856 find_what_p_points_to (ptr);
6859 /* Compute the call-use and call-clobber sets for all direct calls. */
6860 fi = lookup_vi_for_tree (node->decl);
6861 gcc_assert (fi->is_fn_info);
6862 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6864 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6865 for (e = node->callers; e; e = e->next_caller)
6870 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6871 *gimple_call_use_set (e->call_stmt) = uses;
6874 /* Compute the call-use and call-clobber sets for indirect calls
6875 and calls to external functions. */
6876 FOR_EACH_BB_FN (bb, fn)
6878 gimple_stmt_iterator gsi;
6880 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6882 gimple stmt = gsi_stmt (gsi);
6883 struct pt_solution *pt;
6887 if (!is_gimple_call (stmt))
6890 /* Handle direct calls to external functions. */
6891 decl = gimple_call_fndecl (stmt);
6893 && (!(fi = lookup_vi_for_tree (decl))
6894 || !fi->is_fn_info))
6896 pt = gimple_call_use_set (stmt);
6897 if (gimple_call_flags (stmt) & ECF_CONST)
6898 memset (pt, 0, sizeof (struct pt_solution));
6899 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6901 find_what_var_points_to (vi, pt);
6902 /* Escaped (and thus nonlocal) variables are always
6903 implicitly used by calls. */
6904 /* ??? ESCAPED can be empty even though NONLOCAL
6907 pt->ipa_escaped = 1;
6911 /* If there is nothing special about this call then
6912 we have made everything that is used also escape. */
6913 *pt = ipa_escaped_pt;
6917 pt = gimple_call_clobber_set (stmt);
6918 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6919 memset (pt, 0, sizeof (struct pt_solution));
6920 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6922 find_what_var_points_to (vi, pt);
6923 /* Escaped (and thus nonlocal) variables are always
6924 implicitly clobbered by calls. */
6925 /* ??? ESCAPED can be empty even though NONLOCAL
6928 pt->ipa_escaped = 1;
6932 /* If there is nothing special about this call then
6933 we have made everything that is used also escape. */
6934 *pt = ipa_escaped_pt;
6939 /* Handle indirect calls. */
6941 && (fi = get_fi_for_callee (stmt)))
6943 /* We need to accumulate all clobbers/uses of all possible
6945 fi = get_varinfo (find (fi->id));
6946 /* If we cannot constrain the set of functions we'll end up
6947 calling we end up using/clobbering everything. */
6948 if (bitmap_bit_p (fi->solution, anything_id)
6949 || bitmap_bit_p (fi->solution, nonlocal_id)
6950 || bitmap_bit_p (fi->solution, escaped_id))
6952 pt_solution_reset (gimple_call_clobber_set (stmt));
6953 pt_solution_reset (gimple_call_use_set (stmt));
6959 struct pt_solution *uses, *clobbers;
6961 uses = gimple_call_use_set (stmt);
6962 clobbers = gimple_call_clobber_set (stmt);
6963 memset (uses, 0, sizeof (struct pt_solution));
6964 memset (clobbers, 0, sizeof (struct pt_solution));
6965 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6967 struct pt_solution sol;
6969 vi = get_varinfo (i);
6970 if (!vi->is_fn_info)
6972 /* ??? We could be more precise here? */
6974 uses->ipa_escaped = 1;
6975 clobbers->nonlocal = 1;
6976 clobbers->ipa_escaped = 1;
6980 if (!uses->anything)
6982 find_what_var_points_to
6983 (first_vi_for_offset (vi, fi_uses), &sol);
6984 pt_solution_ior_into (uses, &sol);
6986 if (!clobbers->anything)
6988 find_what_var_points_to
6989 (first_vi_for_offset (vi, fi_clobbers), &sol);
6990 pt_solution_ior_into (clobbers, &sol);
6998 fn->gimple_df->ipa_pta = true;
7001 delete_points_to_sets ();
7008 struct simple_ipa_opt_pass pass_ipa_pta =
7013 gate_ipa_pta, /* gate */
7014 ipa_pta_execute, /* execute */
7017 0, /* static_pass_number */
7018 TV_IPA_PTA, /* tv_id */
7019 0, /* properties_required */
7020 0, /* properties_provided */
7021 0, /* properties_destroyed */
7022 0, /* todo_flags_start */
7023 TODO_update_ssa /* todo_flags_finish */
7028 #include "gt-tree-ssa-structalias.h"