1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dberlin@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "basic-block.h"
33 #include "tree-flow.h"
34 #include "tree-inline.h"
35 #include "diagnostic-core.h"
40 #include "tree-pass.h"
42 #include "alloc-pool.h"
43 #include "splay-tree.h"
47 #include "pointer-set.h"
49 /* The idea behind this analyzer is to generate set constraints from the
50 program, then solve the resulting constraints in order to generate the
53 Set constraints are a way of modeling program analysis problems that
54 involve sets. They consist of an inclusion constraint language,
55 describing the variables (each variable is a set) and operations that
56 are involved on the variables, and a set of rules that derive facts
57 from these operations. To solve a system of set constraints, you derive
58 all possible facts under the rules, which gives you the correct sets
61 See "Efficient Field-sensitive pointer analysis for C" by "David
62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
63 http://citeseer.ist.psu.edu/pearce04efficient.html
65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
67 http://citeseer.ist.psu.edu/heintze01ultrafast.html
69 There are three types of real constraint expressions, DEREF,
70 ADDRESSOF, and SCALAR. Each constraint expression consists
71 of a constraint type, a variable, and an offset.
73 SCALAR is a constraint expression type used to represent x, whether
74 it appears on the LHS or the RHS of a statement.
75 DEREF is a constraint expression type used to represent *x, whether
76 it appears on the LHS or the RHS of a statement.
77 ADDRESSOF is a constraint expression used to represent &x, whether
78 it appears on the LHS or the RHS of a statement.
80 Each pointer variable in the program is assigned an integer id, and
81 each field of a structure variable is assigned an integer id as well.
83 Structure variables are linked to their list of fields through a "next
84 field" in each variable that points to the next field in offset
86 Each variable for a structure field has
88 1. "size", that tells the size in bits of that field.
89 2. "fullsize, that tells the size in bits of the entire structure.
90 3. "offset", that tells the offset in bits from the beginning of the
91 structure to this field.
103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
108 In order to solve the system of set constraints, the following is
111 1. Each constraint variable x has a solution set associated with it,
114 2. Constraints are separated into direct, copy, and complex.
115 Direct constraints are ADDRESSOF constraints that require no extra
116 processing, such as P = &Q
117 Copy constraints are those of the form P = Q.
118 Complex constraints are all the constraints involving dereferences
119 and offsets (including offsetted copies).
121 3. All direct constraints of the form P = &Q are processed, such
122 that Q is added to Sol(P)
124 4. All complex constraints for a given constraint variable are stored in a
125 linked list attached to that variable's node.
127 5. A directed graph is built out of the copy constraints. Each
128 constraint variable is a node in the graph, and an edge from
129 Q to P is added for each copy constraint of the form P = Q
131 6. The graph is then walked, and solution sets are
132 propagated along the copy edges, such that an edge from Q to P
133 causes Sol(P) <- Sol(P) union Sol(Q).
135 7. As we visit each node, all complex constraints associated with
136 that node are processed by adding appropriate copy edges to the graph, or the
137 appropriate variables to the solution set.
139 8. The process of walking the graph is iterated until no solution
142 Prior to walking the graph in steps 6 and 7, We perform static
143 cycle elimination on the constraint graph, as well
144 as off-line variable substitution.
146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
147 on and turned into anything), but isn't. You can just see what offset
148 inside the pointed-to struct it's going to access.
150 TODO: Constant bounded arrays can be handled as if they were structs of the
151 same number of elements.
153 TODO: Modeling heap and incoming pointers becomes much better if we
154 add fields to them as we discover them, which we could do.
156 TODO: We could handle unions, but to be honest, it's probably not
157 worth the pain or slowdown. */
159 /* IPA-PTA optimizations possible.
161 When the indirect function called is ANYTHING we can add disambiguation
162 based on the function signatures (or simply the parameter count which
163 is the varinfo size). We also do not need to consider functions that
164 do not have their address taken.
166 The is_global_var bit which marks escape points is overly conservative
167 in IPA mode. Split it to is_escape_point and is_global_var - only
168 externally visible globals are escape points in IPA mode. This is
169 also needed to fix the pt_solution_includes_global predicate
170 (and thus ptr_deref_may_alias_global_p).
172 The way we introduce DECL_PT_UID to avoid fixing up all points-to
173 sets in the translation unit when we copy a DECL during inlining
174 pessimizes precision. The advantage is that the DECL_PT_UID keeps
175 compile-time and memory usage overhead low - the points-to sets
176 do not grow or get unshared as they would during a fixup phase.
177 An alternative solution is to delay IPA PTA until after all
178 inlining transformations have been applied.
180 The way we propagate clobber/use information isn't optimized.
181 It should use a new complex constraint that properly filters
182 out local variables of the callee (though that would make
183 the sets invalid after inlining). OTOH we might as well
184 admit defeat to WHOPR and simply do all the clobber/use analysis
185 and propagation after PTA finished but before we threw away
186 points-to information for memory variables. WHOPR and PTA
187 do not play along well anyway - the whole constraint solving
188 would need to be done in WPA phase and it will be very interesting
189 to apply the results to local SSA names during LTRANS phase.
191 We probably should compute a per-function unit-ESCAPE solution
192 propagating it simply like the clobber / uses solutions. The
193 solution can go alongside the non-IPA espaced solution and be
194 used to query which vars escape the unit through a function.
196 We never put function decls in points-to sets so we do not
197 keep the set of called functions for indirect calls.
199 And probably more. */
201 static bool use_field_sensitive = true;
202 static int in_ipa_mode = 0;
204 /* Used for predecessor bitmaps. */
205 static bitmap_obstack predbitmap_obstack;
207 /* Used for points-to sets. */
208 static bitmap_obstack pta_obstack;
210 /* Used for oldsolution members of variables. */
211 static bitmap_obstack oldpta_obstack;
213 /* Used for per-solver-iteration bitmaps. */
214 static bitmap_obstack iteration_obstack;
216 static unsigned int create_variable_info_for (tree, const char *);
217 typedef struct constraint_graph *constraint_graph_t;
218 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
221 typedef struct constraint *constraint_t;
223 DEF_VEC_P(constraint_t);
224 DEF_VEC_ALLOC_P(constraint_t,heap);
226 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
228 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
230 static struct constraint_stats
232 unsigned int total_vars;
233 unsigned int nonpointer_vars;
234 unsigned int unified_vars_static;
235 unsigned int unified_vars_dynamic;
236 unsigned int iterations;
237 unsigned int num_edges;
238 unsigned int num_implicit_edges;
239 unsigned int points_to_sets_created;
244 /* ID of this variable */
247 /* True if this is a variable created by the constraint analysis, such as
248 heap variables and constraints we had to break up. */
249 unsigned int is_artificial_var : 1;
251 /* True if this is a special variable whose solution set should not be
253 unsigned int is_special_var : 1;
255 /* True for variables whose size is not known or variable. */
256 unsigned int is_unknown_size_var : 1;
258 /* True for (sub-)fields that represent a whole variable. */
259 unsigned int is_full_var : 1;
261 /* True if this is a heap variable. */
262 unsigned int is_heap_var : 1;
264 /* True if this is a variable tracking a restrict pointer source. */
265 unsigned int is_restrict_var : 1;
267 /* True if this field may contain pointers. */
268 unsigned int may_have_pointers : 1;
270 /* True if this field has only restrict qualified pointers. */
271 unsigned int only_restrict_pointers : 1;
273 /* True if this represents a global variable. */
274 unsigned int is_global_var : 1;
276 /* True if this represents a IPA function info. */
277 unsigned int is_fn_info : 1;
279 /* A link to the variable for the next field in this structure. */
280 struct variable_info *next;
282 /* Offset of this variable, in bits, from the base variable */
283 unsigned HOST_WIDE_INT offset;
285 /* Size of the variable, in bits. */
286 unsigned HOST_WIDE_INT size;
288 /* Full size of the base variable, in bits. */
289 unsigned HOST_WIDE_INT fullsize;
291 /* Name of this variable */
294 /* Tree that this variable is associated with. */
297 /* Points-to set for this variable. */
300 /* Old points-to set for this variable. */
303 typedef struct variable_info *varinfo_t;
305 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
306 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
307 unsigned HOST_WIDE_INT);
308 static varinfo_t lookup_vi_for_tree (tree);
310 /* Pool of variable info structures. */
311 static alloc_pool variable_info_pool;
313 DEF_VEC_P(varinfo_t);
315 DEF_VEC_ALLOC_P(varinfo_t, heap);
317 /* Table of variable info structures for constraint variables.
318 Indexed directly by variable info id. */
319 static VEC(varinfo_t,heap) *varmap;
321 /* Return the varmap element N */
323 static inline varinfo_t
324 get_varinfo (unsigned int n)
326 return VEC_index (varinfo_t, varmap, n);
329 /* Static IDs for the special variables. */
330 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
331 escaped_id = 3, nonlocal_id = 4,
332 storedanything_id = 5, integer_id = 6 };
334 /* Return a new variable info structure consisting for a variable
335 named NAME, and using constraint graph node NODE. Append it
336 to the vector of variable info structures. */
339 new_var_info (tree t, const char *name)
341 unsigned index = VEC_length (varinfo_t, varmap);
342 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
347 /* Vars without decl are artificial and do not have sub-variables. */
348 ret->is_artificial_var = (t == NULL_TREE);
349 ret->is_special_var = false;
350 ret->is_unknown_size_var = false;
351 ret->is_full_var = (t == NULL_TREE);
352 ret->is_heap_var = false;
353 ret->is_restrict_var = false;
354 ret->may_have_pointers = true;
355 ret->only_restrict_pointers = false;
356 ret->is_global_var = (t == NULL_TREE);
357 ret->is_fn_info = false;
359 ret->is_global_var = (is_global_var (t)
360 /* We have to treat even local register variables
362 || (TREE_CODE (t) == VAR_DECL
363 && DECL_HARD_REGISTER (t)));
364 ret->solution = BITMAP_ALLOC (&pta_obstack);
365 ret->oldsolution = NULL;
370 VEC_safe_push (varinfo_t, heap, varmap, ret);
376 /* A map mapping call statements to per-stmt variables for uses
377 and clobbers specific to the call. */
378 struct pointer_map_t *call_stmt_vars;
380 /* Lookup or create the variable for the call statement CALL. */
383 get_call_vi (gimple call)
388 slot_p = pointer_map_insert (call_stmt_vars, call);
390 return (varinfo_t) *slot_p;
392 vi = new_var_info (NULL_TREE, "CALLUSED");
396 vi->is_full_var = true;
398 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
402 vi2->is_full_var = true;
404 *slot_p = (void *) vi;
408 /* Lookup the variable for the call statement CALL representing
409 the uses. Returns NULL if there is nothing special about this call. */
412 lookup_call_use_vi (gimple call)
416 slot_p = pointer_map_contains (call_stmt_vars, call);
418 return (varinfo_t) *slot_p;
423 /* Lookup the variable for the call statement CALL representing
424 the clobbers. Returns NULL if there is nothing special about this call. */
427 lookup_call_clobber_vi (gimple call)
429 varinfo_t uses = lookup_call_use_vi (call);
436 /* Lookup or create the variable for the call statement CALL representing
440 get_call_use_vi (gimple call)
442 return get_call_vi (call);
445 /* Lookup or create the variable for the call statement CALL representing
448 static varinfo_t ATTRIBUTE_UNUSED
449 get_call_clobber_vi (gimple call)
451 return get_call_vi (call)->next;
455 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
457 /* An expression that appears in a constraint. */
459 struct constraint_expr
461 /* Constraint type. */
462 constraint_expr_type type;
464 /* Variable we are referring to in the constraint. */
467 /* Offset, in bits, of this constraint from the beginning of
468 variables it ends up referring to.
470 IOW, in a deref constraint, we would deref, get the result set,
471 then add OFFSET to each member. */
472 HOST_WIDE_INT offset;
475 /* Use 0x8000... as special unknown offset. */
476 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
478 typedef struct constraint_expr ce_s;
480 DEF_VEC_ALLOC_O(ce_s, heap);
481 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
482 static void get_constraint_for (tree, VEC(ce_s, heap) **);
483 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
484 static void do_deref (VEC (ce_s, heap) **);
486 /* Our set constraints are made up of two constraint expressions, one
489 As described in the introduction, our set constraints each represent an
490 operation between set valued variables.
494 struct constraint_expr lhs;
495 struct constraint_expr rhs;
498 /* List of constraints that we use to build the constraint graph from. */
500 static VEC(constraint_t,heap) *constraints;
501 static alloc_pool constraint_pool;
503 /* The constraint graph is represented as an array of bitmaps
504 containing successor nodes. */
506 struct constraint_graph
508 /* Size of this graph, which may be different than the number of
509 nodes in the variable map. */
512 /* Explicit successors of each node. */
515 /* Implicit predecessors of each node (Used for variable
517 bitmap *implicit_preds;
519 /* Explicit predecessors of each node (Used for variable substitution). */
522 /* Indirect cycle representatives, or -1 if the node has no indirect
524 int *indirect_cycles;
526 /* Representative node for a node. rep[a] == a unless the node has
530 /* Equivalence class representative for a label. This is used for
531 variable substitution. */
534 /* Pointer equivalence label for a node. All nodes with the same
535 pointer equivalence label can be unified together at some point
536 (either during constraint optimization or after the constraint
540 /* Pointer equivalence representative for a label. This is used to
541 handle nodes that are pointer equivalent but not location
542 equivalent. We can unite these once the addressof constraints
543 are transformed into initial points-to sets. */
546 /* Pointer equivalence label for each node, used during variable
548 unsigned int *pointer_label;
550 /* Location equivalence label for each node, used during location
551 equivalence finding. */
552 unsigned int *loc_label;
554 /* Pointed-by set for each node, used during location equivalence
555 finding. This is pointed-by rather than pointed-to, because it
556 is constructed using the predecessor graph. */
559 /* Points to sets for pointer equivalence. This is *not* the actual
560 points-to sets for nodes. */
563 /* Bitmap of nodes where the bit is set if the node is a direct
564 node. Used for variable substitution. */
565 sbitmap direct_nodes;
567 /* Bitmap of nodes where the bit is set if the node is address
568 taken. Used for variable substitution. */
569 bitmap address_taken;
571 /* Vector of complex constraints for each graph node. Complex
572 constraints are those involving dereferences or offsets that are
574 VEC(constraint_t,heap) **complex;
577 static constraint_graph_t graph;
579 /* During variable substitution and the offline version of indirect
580 cycle finding, we create nodes to represent dereferences and
581 address taken constraints. These represent where these start and
583 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
584 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
586 /* Return the representative node for NODE, if NODE has been unioned
588 This function performs path compression along the way to finding
589 the representative. */
592 find (unsigned int node)
594 gcc_assert (node < graph->size);
595 if (graph->rep[node] != node)
596 return graph->rep[node] = find (graph->rep[node]);
600 /* Union the TO and FROM nodes to the TO nodes.
601 Note that at some point in the future, we may want to do
602 union-by-rank, in which case we are going to have to return the
603 node we unified to. */
606 unite (unsigned int to, unsigned int from)
608 gcc_assert (to < graph->size && from < graph->size);
609 if (to != from && graph->rep[from] != to)
611 graph->rep[from] = to;
617 /* Create a new constraint consisting of LHS and RHS expressions. */
620 new_constraint (const struct constraint_expr lhs,
621 const struct constraint_expr rhs)
623 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
629 /* Print out constraint C to FILE. */
632 dump_constraint (FILE *file, constraint_t c)
634 if (c->lhs.type == ADDRESSOF)
636 else if (c->lhs.type == DEREF)
638 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
639 if (c->lhs.offset == UNKNOWN_OFFSET)
640 fprintf (file, " + UNKNOWN");
641 else if (c->lhs.offset != 0)
642 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
643 fprintf (file, " = ");
644 if (c->rhs.type == ADDRESSOF)
646 else if (c->rhs.type == DEREF)
648 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
649 if (c->rhs.offset == UNKNOWN_OFFSET)
650 fprintf (file, " + UNKNOWN");
651 else if (c->rhs.offset != 0)
652 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
656 void debug_constraint (constraint_t);
657 void debug_constraints (void);
658 void debug_constraint_graph (void);
659 void debug_solution_for_var (unsigned int);
660 void debug_sa_points_to_info (void);
662 /* Print out constraint C to stderr. */
665 debug_constraint (constraint_t c)
667 dump_constraint (stderr, c);
668 fprintf (stderr, "\n");
671 /* Print out all constraints to FILE */
674 dump_constraints (FILE *file, int from)
678 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
681 dump_constraint (file, c);
682 fprintf (file, "\n");
686 /* Print out all constraints to stderr. */
689 debug_constraints (void)
691 dump_constraints (stderr, 0);
694 /* Print the constraint graph in dot format. */
697 dump_constraint_graph (FILE *file)
701 /* Only print the graph if it has already been initialized: */
705 /* Prints the header of the dot file: */
706 fprintf (file, "strict digraph {\n");
707 fprintf (file, " node [\n shape = box\n ]\n");
708 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
709 fprintf (file, "\n // List of nodes and complex constraints in "
710 "the constraint graph:\n");
712 /* The next lines print the nodes in the graph together with the
713 complex constraints attached to them. */
714 for (i = 0; i < graph->size; i++)
718 if (i < FIRST_REF_NODE)
719 fprintf (file, "\"%s\"", get_varinfo (i)->name);
721 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
722 if (graph->complex[i])
726 fprintf (file, " [label=\"\\N\\n");
727 for (j = 0; VEC_iterate (constraint_t, graph->complex[i], j, c); ++j)
729 dump_constraint (file, c);
730 fprintf (file, "\\l");
732 fprintf (file, "\"]");
734 fprintf (file, ";\n");
737 /* Go over the edges. */
738 fprintf (file, "\n // Edges in the constraint graph:\n");
739 for (i = 0; i < graph->size; i++)
745 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi)
747 unsigned to = find (j);
750 if (i < FIRST_REF_NODE)
751 fprintf (file, "\"%s\"", get_varinfo (i)->name);
753 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
754 fprintf (file, " -> ");
755 if (to < FIRST_REF_NODE)
756 fprintf (file, "\"%s\"", get_varinfo (to)->name);
758 fprintf (file, "\"*%s\"", get_varinfo (to - FIRST_REF_NODE)->name);
759 fprintf (file, ";\n");
763 /* Prints the tail of the dot file. */
764 fprintf (file, "}\n");
767 /* Print out the constraint graph to stderr. */
770 debug_constraint_graph (void)
772 dump_constraint_graph (stderr);
777 The solver is a simple worklist solver, that works on the following
780 sbitmap changed_nodes = all zeroes;
782 For each node that is not already collapsed:
784 set bit in changed nodes
786 while (changed_count > 0)
788 compute topological ordering for constraint graph
790 find and collapse cycles in the constraint graph (updating
791 changed if necessary)
793 for each node (n) in the graph in topological order:
796 Process each complex constraint associated with the node,
797 updating changed if necessary.
799 For each outgoing edge from n, propagate the solution from n to
800 the destination of the edge, updating changed as necessary.
804 /* Return true if two constraint expressions A and B are equal. */
807 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
809 return a.type == b.type && a.var == b.var && a.offset == b.offset;
812 /* Return true if constraint expression A is less than constraint expression
813 B. This is just arbitrary, but consistent, in order to give them an
817 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
819 if (a.type == b.type)
822 return a.offset < b.offset;
824 return a.var < b.var;
827 return a.type < b.type;
830 /* Return true if constraint A is less than constraint B. This is just
831 arbitrary, but consistent, in order to give them an ordering. */
834 constraint_less (const constraint_t a, const constraint_t b)
836 if (constraint_expr_less (a->lhs, b->lhs))
838 else if (constraint_expr_less (b->lhs, a->lhs))
841 return constraint_expr_less (a->rhs, b->rhs);
844 /* Return true if two constraints A and B are equal. */
847 constraint_equal (struct constraint a, struct constraint b)
849 return constraint_expr_equal (a.lhs, b.lhs)
850 && constraint_expr_equal (a.rhs, b.rhs);
854 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
857 constraint_vec_find (VEC(constraint_t,heap) *vec,
858 struct constraint lookfor)
866 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
867 if (place >= VEC_length (constraint_t, vec))
869 found = VEC_index (constraint_t, vec, place);
870 if (!constraint_equal (*found, lookfor))
875 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
878 constraint_set_union (VEC(constraint_t,heap) **to,
879 VEC(constraint_t,heap) **from)
884 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
886 if (constraint_vec_find (*to, *c) == NULL)
888 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
890 VEC_safe_insert (constraint_t, heap, *to, place, c);
895 /* Expands the solution in SET to all sub-fields of variables included.
896 Union the expanded result into RESULT. */
899 solution_set_expand (bitmap result, bitmap set)
905 /* In a first pass record all variables we need to add all
906 sub-fields off. This avoids quadratic behavior. */
907 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
909 varinfo_t v = get_varinfo (j);
910 if (v->is_artificial_var
913 v = lookup_vi_for_tree (v->decl);
915 vars = BITMAP_ALLOC (NULL);
916 bitmap_set_bit (vars, v->id);
919 /* In the second pass now do the addition to the solution and
920 to speed up solving add it to the delta as well. */
923 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
925 varinfo_t v = get_varinfo (j);
926 for (; v != NULL; v = v->next)
927 bitmap_set_bit (result, v->id);
933 /* Take a solution set SET, add OFFSET to each member of the set, and
934 overwrite SET with the result when done. */
937 solution_set_add (bitmap set, HOST_WIDE_INT offset)
939 bitmap result = BITMAP_ALLOC (&iteration_obstack);
943 /* If the offset is unknown we have to expand the solution to
945 if (offset == UNKNOWN_OFFSET)
947 solution_set_expand (set, set);
951 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
953 varinfo_t vi = get_varinfo (i);
955 /* If this is a variable with just one field just set its bit
957 if (vi->is_artificial_var
958 || vi->is_unknown_size_var
960 bitmap_set_bit (result, i);
963 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
965 /* If the offset makes the pointer point to before the
966 variable use offset zero for the field lookup. */
968 && fieldoffset > vi->offset)
972 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
974 bitmap_set_bit (result, vi->id);
975 /* If the result is not exactly at fieldoffset include the next
976 field as well. See get_constraint_for_ptr_offset for more
978 if (vi->offset != fieldoffset
980 bitmap_set_bit (result, vi->next->id);
984 bitmap_copy (set, result);
985 BITMAP_FREE (result);
988 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
992 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
995 return bitmap_ior_into (to, from);
1001 tmp = BITMAP_ALLOC (&iteration_obstack);
1002 bitmap_copy (tmp, from);
1003 solution_set_add (tmp, inc);
1004 res = bitmap_ior_into (to, tmp);
1010 /* Insert constraint C into the list of complex constraints for graph
1014 insert_into_complex (constraint_graph_t graph,
1015 unsigned int var, constraint_t c)
1017 VEC (constraint_t, heap) *complex = graph->complex[var];
1018 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1021 /* Only insert constraints that do not already exist. */
1022 if (place >= VEC_length (constraint_t, complex)
1023 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1024 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1028 /* Condense two variable nodes into a single variable node, by moving
1029 all associated info from SRC to TO. */
1032 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1038 gcc_assert (find (from) == to);
1040 /* Move all complex constraints from src node into to node */
1041 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1043 /* In complex constraints for node src, we may have either
1044 a = *src, and *src = a, or an offseted constraint which are
1045 always added to the rhs node's constraints. */
1047 if (c->rhs.type == DEREF)
1049 else if (c->lhs.type == DEREF)
1054 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1055 VEC_free (constraint_t, heap, graph->complex[from]);
1056 graph->complex[from] = NULL;
1060 /* Remove edges involving NODE from GRAPH. */
1063 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1065 if (graph->succs[node])
1066 BITMAP_FREE (graph->succs[node]);
1069 /* Merge GRAPH nodes FROM and TO into node TO. */
1072 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1075 if (graph->indirect_cycles[from] != -1)
1077 /* If we have indirect cycles with the from node, and we have
1078 none on the to node, the to node has indirect cycles from the
1079 from node now that they are unified.
1080 If indirect cycles exist on both, unify the nodes that they
1081 are in a cycle with, since we know they are in a cycle with
1083 if (graph->indirect_cycles[to] == -1)
1084 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1087 /* Merge all the successor edges. */
1088 if (graph->succs[from])
1090 if (!graph->succs[to])
1091 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1092 bitmap_ior_into (graph->succs[to],
1093 graph->succs[from]);
1096 clear_edges_for_node (graph, from);
1100 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1101 it doesn't exist in the graph already. */
1104 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1110 if (!graph->implicit_preds[to])
1111 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1113 if (bitmap_set_bit (graph->implicit_preds[to], from))
1114 stats.num_implicit_edges++;
1117 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1118 it doesn't exist in the graph already.
1119 Return false if the edge already existed, true otherwise. */
1122 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1125 if (!graph->preds[to])
1126 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1127 bitmap_set_bit (graph->preds[to], from);
1130 /* Add a graph edge to GRAPH, going from FROM to TO if
1131 it doesn't exist in the graph already.
1132 Return false if the edge already existed, true otherwise. */
1135 add_graph_edge (constraint_graph_t graph, unsigned int to,
1146 if (!graph->succs[from])
1147 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1148 if (bitmap_set_bit (graph->succs[from], to))
1151 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1159 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1162 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1165 return (graph->succs[dest]
1166 && bitmap_bit_p (graph->succs[dest], src));
1169 /* Initialize the constraint graph structure to contain SIZE nodes. */
1172 init_graph (unsigned int size)
1176 graph = XCNEW (struct constraint_graph);
1178 graph->succs = XCNEWVEC (bitmap, graph->size);
1179 graph->indirect_cycles = XNEWVEC (int, graph->size);
1180 graph->rep = XNEWVEC (unsigned int, graph->size);
1181 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1182 graph->pe = XCNEWVEC (unsigned int, graph->size);
1183 graph->pe_rep = XNEWVEC (int, graph->size);
1185 for (j = 0; j < graph->size; j++)
1188 graph->pe_rep[j] = -1;
1189 graph->indirect_cycles[j] = -1;
1193 /* Build the constraint graph, adding only predecessor edges right now. */
1196 build_pred_graph (void)
1202 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1203 graph->preds = XCNEWVEC (bitmap, graph->size);
1204 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1205 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1206 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1207 graph->points_to = XCNEWVEC (bitmap, graph->size);
1208 graph->eq_rep = XNEWVEC (int, graph->size);
1209 graph->direct_nodes = sbitmap_alloc (graph->size);
1210 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1211 sbitmap_zero (graph->direct_nodes);
1213 for (j = 0; j < FIRST_REF_NODE; j++)
1215 if (!get_varinfo (j)->is_special_var)
1216 SET_BIT (graph->direct_nodes, j);
1219 for (j = 0; j < graph->size; j++)
1220 graph->eq_rep[j] = -1;
1222 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1223 graph->indirect_cycles[j] = -1;
1225 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1227 struct constraint_expr lhs = c->lhs;
1228 struct constraint_expr rhs = c->rhs;
1229 unsigned int lhsvar = lhs.var;
1230 unsigned int rhsvar = rhs.var;
1232 if (lhs.type == DEREF)
1235 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1236 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1238 else if (rhs.type == DEREF)
1241 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1242 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1244 RESET_BIT (graph->direct_nodes, lhsvar);
1246 else if (rhs.type == ADDRESSOF)
1251 if (graph->points_to[lhsvar] == NULL)
1252 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1253 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1255 if (graph->pointed_by[rhsvar] == NULL)
1256 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1257 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1259 /* Implicitly, *x = y */
1260 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1262 /* All related variables are no longer direct nodes. */
1263 RESET_BIT (graph->direct_nodes, rhsvar);
1264 v = get_varinfo (rhsvar);
1265 if (!v->is_full_var)
1267 v = lookup_vi_for_tree (v->decl);
1270 RESET_BIT (graph->direct_nodes, v->id);
1275 bitmap_set_bit (graph->address_taken, rhsvar);
1277 else if (lhsvar > anything_id
1278 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1281 add_pred_graph_edge (graph, lhsvar, rhsvar);
1282 /* Implicitly, *x = *y */
1283 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1284 FIRST_REF_NODE + rhsvar);
1286 else if (lhs.offset != 0 || rhs.offset != 0)
1288 if (rhs.offset != 0)
1289 RESET_BIT (graph->direct_nodes, lhs.var);
1290 else if (lhs.offset != 0)
1291 RESET_BIT (graph->direct_nodes, rhs.var);
1296 /* Build the constraint graph, adding successor edges. */
1299 build_succ_graph (void)
1304 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1306 struct constraint_expr lhs;
1307 struct constraint_expr rhs;
1308 unsigned int lhsvar;
1309 unsigned int rhsvar;
1316 lhsvar = find (lhs.var);
1317 rhsvar = find (rhs.var);
1319 if (lhs.type == DEREF)
1321 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1322 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1324 else if (rhs.type == DEREF)
1326 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1327 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1329 else if (rhs.type == ADDRESSOF)
1332 gcc_assert (find (rhs.var) == rhs.var);
1333 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1335 else if (lhsvar > anything_id
1336 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1338 add_graph_edge (graph, lhsvar, rhsvar);
1342 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1343 receive pointers. */
1344 t = find (storedanything_id);
1345 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1347 if (!TEST_BIT (graph->direct_nodes, i)
1348 && get_varinfo (i)->may_have_pointers)
1349 add_graph_edge (graph, find (i), t);
1352 /* Everything stored to ANYTHING also potentially escapes. */
1353 add_graph_edge (graph, find (escaped_id), t);
1357 /* Changed variables on the last iteration. */
1358 static bitmap changed;
1360 /* Strongly Connected Component visitation info. */
1367 unsigned int *node_mapping;
1369 VEC(unsigned,heap) *scc_stack;
1373 /* Recursive routine to find strongly connected components in GRAPH.
1374 SI is the SCC info to store the information in, and N is the id of current
1375 graph node we are processing.
1377 This is Tarjan's strongly connected component finding algorithm, as
1378 modified by Nuutila to keep only non-root nodes on the stack.
1379 The algorithm can be found in "On finding the strongly connected
1380 connected components in a directed graph" by Esko Nuutila and Eljas
1381 Soisalon-Soininen, in Information Processing Letters volume 49,
1382 number 1, pages 9-14. */
1385 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1389 unsigned int my_dfs;
1391 SET_BIT (si->visited, n);
1392 si->dfs[n] = si->current_index ++;
1393 my_dfs = si->dfs[n];
1395 /* Visit all the successors. */
1396 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1400 if (i > LAST_REF_NODE)
1404 if (TEST_BIT (si->deleted, w))
1407 if (!TEST_BIT (si->visited, w))
1408 scc_visit (graph, si, w);
1410 unsigned int t = find (w);
1411 unsigned int nnode = find (n);
1412 gcc_assert (nnode == n);
1414 if (si->dfs[t] < si->dfs[nnode])
1415 si->dfs[n] = si->dfs[t];
1419 /* See if any components have been identified. */
1420 if (si->dfs[n] == my_dfs)
1422 if (VEC_length (unsigned, si->scc_stack) > 0
1423 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1425 bitmap scc = BITMAP_ALLOC (NULL);
1426 unsigned int lowest_node;
1429 bitmap_set_bit (scc, n);
1431 while (VEC_length (unsigned, si->scc_stack) != 0
1432 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1434 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1436 bitmap_set_bit (scc, w);
1439 lowest_node = bitmap_first_set_bit (scc);
1440 gcc_assert (lowest_node < FIRST_REF_NODE);
1442 /* Collapse the SCC nodes into a single node, and mark the
1444 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1446 if (i < FIRST_REF_NODE)
1448 if (unite (lowest_node, i))
1449 unify_nodes (graph, lowest_node, i, false);
1453 unite (lowest_node, i);
1454 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1458 SET_BIT (si->deleted, n);
1461 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1464 /* Unify node FROM into node TO, updating the changed count if
1465 necessary when UPDATE_CHANGED is true. */
1468 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1469 bool update_changed)
1472 gcc_assert (to != from && find (to) == to);
1473 if (dump_file && (dump_flags & TDF_DETAILS))
1474 fprintf (dump_file, "Unifying %s to %s\n",
1475 get_varinfo (from)->name,
1476 get_varinfo (to)->name);
1479 stats.unified_vars_dynamic++;
1481 stats.unified_vars_static++;
1483 merge_graph_nodes (graph, to, from);
1484 merge_node_constraints (graph, to, from);
1486 /* Mark TO as changed if FROM was changed. If TO was already marked
1487 as changed, decrease the changed count. */
1490 && bitmap_bit_p (changed, from))
1492 bitmap_clear_bit (changed, from);
1493 bitmap_set_bit (changed, to);
1495 if (get_varinfo (from)->solution)
1497 /* If the solution changes because of the merging, we need to mark
1498 the variable as changed. */
1499 if (bitmap_ior_into (get_varinfo (to)->solution,
1500 get_varinfo (from)->solution))
1503 bitmap_set_bit (changed, to);
1506 BITMAP_FREE (get_varinfo (from)->solution);
1507 if (get_varinfo (from)->oldsolution)
1508 BITMAP_FREE (get_varinfo (from)->oldsolution);
1510 if (stats.iterations > 0
1511 && get_varinfo (to)->oldsolution)
1512 BITMAP_FREE (get_varinfo (to)->oldsolution);
1514 if (valid_graph_edge (graph, to, to))
1516 if (graph->succs[to])
1517 bitmap_clear_bit (graph->succs[to], to);
1521 /* Information needed to compute the topological ordering of a graph. */
1525 /* sbitmap of visited nodes. */
1527 /* Array that stores the topological order of the graph, *in
1529 VEC(unsigned,heap) *topo_order;
1533 /* Initialize and return a topological info structure. */
1535 static struct topo_info *
1536 init_topo_info (void)
1538 size_t size = graph->size;
1539 struct topo_info *ti = XNEW (struct topo_info);
1540 ti->visited = sbitmap_alloc (size);
1541 sbitmap_zero (ti->visited);
1542 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1547 /* Free the topological sort info pointed to by TI. */
1550 free_topo_info (struct topo_info *ti)
1552 sbitmap_free (ti->visited);
1553 VEC_free (unsigned, heap, ti->topo_order);
1557 /* Visit the graph in topological order, and store the order in the
1558 topo_info structure. */
1561 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1567 SET_BIT (ti->visited, n);
1569 if (graph->succs[n])
1570 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1572 if (!TEST_BIT (ti->visited, j))
1573 topo_visit (graph, ti, j);
1576 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1579 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1580 starting solution for y. */
1583 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1586 unsigned int lhs = c->lhs.var;
1588 bitmap sol = get_varinfo (lhs)->solution;
1591 HOST_WIDE_INT roffset = c->rhs.offset;
1593 /* Our IL does not allow this. */
1594 gcc_assert (c->lhs.offset == 0);
1596 /* If the solution of Y contains anything it is good enough to transfer
1598 if (bitmap_bit_p (delta, anything_id))
1600 flag |= bitmap_set_bit (sol, anything_id);
1604 /* If we do not know at with offset the rhs is dereferenced compute
1605 the reachability set of DELTA, conservatively assuming it is
1606 dereferenced at all valid offsets. */
1607 if (roffset == UNKNOWN_OFFSET)
1609 solution_set_expand (delta, delta);
1610 /* No further offset processing is necessary. */
1614 /* For each variable j in delta (Sol(y)), add
1615 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1616 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1618 varinfo_t v = get_varinfo (j);
1619 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1623 fieldoffset = v->offset;
1624 else if (roffset != 0)
1625 v = first_vi_for_offset (v, fieldoffset);
1626 /* If the access is outside of the variable we can ignore it. */
1634 /* Adding edges from the special vars is pointless.
1635 They don't have sets that can change. */
1636 if (get_varinfo (t)->is_special_var)
1637 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1638 /* Merging the solution from ESCAPED needlessly increases
1639 the set. Use ESCAPED as representative instead. */
1640 else if (v->id == escaped_id)
1641 flag |= bitmap_set_bit (sol, escaped_id);
1642 else if (v->may_have_pointers
1643 && add_graph_edge (graph, lhs, t))
1644 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1646 /* If the variable is not exactly at the requested offset
1647 we have to include the next one. */
1648 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1653 fieldoffset = v->offset;
1659 /* If the LHS solution changed, mark the var as changed. */
1662 get_varinfo (lhs)->solution = sol;
1663 bitmap_set_bit (changed, lhs);
1667 /* Process a constraint C that represents *(x + off) = y using DELTA
1668 as the starting solution for x. */
1671 do_ds_constraint (constraint_t c, bitmap delta)
1673 unsigned int rhs = c->rhs.var;
1674 bitmap sol = get_varinfo (rhs)->solution;
1677 HOST_WIDE_INT loff = c->lhs.offset;
1678 bool escaped_p = false;
1680 /* Our IL does not allow this. */
1681 gcc_assert (c->rhs.offset == 0);
1683 /* If the solution of y contains ANYTHING simply use the ANYTHING
1684 solution. This avoids needlessly increasing the points-to sets. */
1685 if (bitmap_bit_p (sol, anything_id))
1686 sol = get_varinfo (find (anything_id))->solution;
1688 /* If the solution for x contains ANYTHING we have to merge the
1689 solution of y into all pointer variables which we do via
1691 if (bitmap_bit_p (delta, anything_id))
1693 unsigned t = find (storedanything_id);
1694 if (add_graph_edge (graph, t, rhs))
1696 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1697 bitmap_set_bit (changed, t);
1702 /* If we do not know at with offset the rhs is dereferenced compute
1703 the reachability set of DELTA, conservatively assuming it is
1704 dereferenced at all valid offsets. */
1705 if (loff == UNKNOWN_OFFSET)
1707 solution_set_expand (delta, delta);
1711 /* For each member j of delta (Sol(x)), add an edge from y to j and
1712 union Sol(y) into Sol(j) */
1713 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1715 varinfo_t v = get_varinfo (j);
1717 HOST_WIDE_INT fieldoffset = v->offset + loff;
1720 fieldoffset = v->offset;
1722 v = first_vi_for_offset (v, fieldoffset);
1723 /* If the access is outside of the variable we can ignore it. */
1729 if (v->may_have_pointers)
1731 /* If v is a global variable then this is an escape point. */
1732 if (v->is_global_var
1735 t = find (escaped_id);
1736 if (add_graph_edge (graph, t, rhs)
1737 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1738 bitmap_set_bit (changed, t);
1739 /* Enough to let rhs escape once. */
1743 if (v->is_special_var)
1747 if (add_graph_edge (graph, t, rhs)
1748 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1749 bitmap_set_bit (changed, t);
1752 /* If the variable is not exactly at the requested offset
1753 we have to include the next one. */
1754 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1759 fieldoffset = v->offset;
1765 /* Handle a non-simple (simple meaning requires no iteration),
1766 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1769 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1771 if (c->lhs.type == DEREF)
1773 if (c->rhs.type == ADDRESSOF)
1780 do_ds_constraint (c, delta);
1783 else if (c->rhs.type == DEREF)
1786 if (!(get_varinfo (c->lhs.var)->is_special_var))
1787 do_sd_constraint (graph, c, delta);
1795 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1796 solution = get_varinfo (c->rhs.var)->solution;
1797 tmp = get_varinfo (c->lhs.var)->solution;
1799 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1803 get_varinfo (c->lhs.var)->solution = tmp;
1804 bitmap_set_bit (changed, c->lhs.var);
1809 /* Initialize and return a new SCC info structure. */
1811 static struct scc_info *
1812 init_scc_info (size_t size)
1814 struct scc_info *si = XNEW (struct scc_info);
1817 si->current_index = 0;
1818 si->visited = sbitmap_alloc (size);
1819 sbitmap_zero (si->visited);
1820 si->deleted = sbitmap_alloc (size);
1821 sbitmap_zero (si->deleted);
1822 si->node_mapping = XNEWVEC (unsigned int, size);
1823 si->dfs = XCNEWVEC (unsigned int, size);
1825 for (i = 0; i < size; i++)
1826 si->node_mapping[i] = i;
1828 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1832 /* Free an SCC info structure pointed to by SI */
1835 free_scc_info (struct scc_info *si)
1837 sbitmap_free (si->visited);
1838 sbitmap_free (si->deleted);
1839 free (si->node_mapping);
1841 VEC_free (unsigned, heap, si->scc_stack);
1846 /* Find indirect cycles in GRAPH that occur, using strongly connected
1847 components, and note them in the indirect cycles map.
1849 This technique comes from Ben Hardekopf and Calvin Lin,
1850 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1851 Lines of Code", submitted to PLDI 2007. */
1854 find_indirect_cycles (constraint_graph_t graph)
1857 unsigned int size = graph->size;
1858 struct scc_info *si = init_scc_info (size);
1860 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1861 if (!TEST_BIT (si->visited, i) && find (i) == i)
1862 scc_visit (graph, si, i);
1867 /* Compute a topological ordering for GRAPH, and store the result in the
1868 topo_info structure TI. */
1871 compute_topo_order (constraint_graph_t graph,
1872 struct topo_info *ti)
1875 unsigned int size = graph->size;
1877 for (i = 0; i != size; ++i)
1878 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1879 topo_visit (graph, ti, i);
1882 /* Structure used to for hash value numbering of pointer equivalence
1885 typedef struct equiv_class_label
1888 unsigned int equivalence_class;
1890 } *equiv_class_label_t;
1891 typedef const struct equiv_class_label *const_equiv_class_label_t;
1893 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1895 static htab_t pointer_equiv_class_table;
1897 /* A hashtable for mapping a bitmap of labels->location equivalence
1899 static htab_t location_equiv_class_table;
1901 /* Hash function for a equiv_class_label_t */
1904 equiv_class_label_hash (const void *p)
1906 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1907 return ecl->hashcode;
1910 /* Equality function for two equiv_class_label_t's. */
1913 equiv_class_label_eq (const void *p1, const void *p2)
1915 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1916 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1917 return (eql1->hashcode == eql2->hashcode
1918 && bitmap_equal_p (eql1->labels, eql2->labels));
1921 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1925 equiv_class_lookup (htab_t table, bitmap labels)
1928 struct equiv_class_label ecl;
1930 ecl.labels = labels;
1931 ecl.hashcode = bitmap_hash (labels);
1933 slot = htab_find_slot_with_hash (table, &ecl,
1934 ecl.hashcode, NO_INSERT);
1938 return ((equiv_class_label_t) *slot)->equivalence_class;
1942 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1946 equiv_class_add (htab_t table, unsigned int equivalence_class,
1950 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1952 ecl->labels = labels;
1953 ecl->equivalence_class = equivalence_class;
1954 ecl->hashcode = bitmap_hash (labels);
1956 slot = htab_find_slot_with_hash (table, ecl,
1957 ecl->hashcode, INSERT);
1958 gcc_assert (!*slot);
1959 *slot = (void *) ecl;
1962 /* Perform offline variable substitution.
1964 This is a worst case quadratic time way of identifying variables
1965 that must have equivalent points-to sets, including those caused by
1966 static cycles, and single entry subgraphs, in the constraint graph.
1968 The technique is described in "Exploiting Pointer and Location
1969 Equivalence to Optimize Pointer Analysis. In the 14th International
1970 Static Analysis Symposium (SAS), August 2007." It is known as the
1971 "HU" algorithm, and is equivalent to value numbering the collapsed
1972 constraint graph including evaluating unions.
1974 The general method of finding equivalence classes is as follows:
1975 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1976 Initialize all non-REF nodes to be direct nodes.
1977 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1979 For each constraint containing the dereference, we also do the same
1982 We then compute SCC's in the graph and unify nodes in the same SCC,
1985 For each non-collapsed node x:
1986 Visit all unvisited explicit incoming edges.
1987 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1989 Lookup the equivalence class for pts(x).
1990 If we found one, equivalence_class(x) = found class.
1991 Otherwise, equivalence_class(x) = new class, and new_class is
1992 added to the lookup table.
1994 All direct nodes with the same equivalence class can be replaced
1995 with a single representative node.
1996 All unlabeled nodes (label == 0) are not pointers and all edges
1997 involving them can be eliminated.
1998 We perform these optimizations during rewrite_constraints
2000 In addition to pointer equivalence class finding, we also perform
2001 location equivalence class finding. This is the set of variables
2002 that always appear together in points-to sets. We use this to
2003 compress the size of the points-to sets. */
2005 /* Current maximum pointer equivalence class id. */
2006 static int pointer_equiv_class;
2008 /* Current maximum location equivalence class id. */
2009 static int location_equiv_class;
2011 /* Recursive routine to find strongly connected components in GRAPH,
2012 and label it's nodes with DFS numbers. */
2015 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2019 unsigned int my_dfs;
2021 gcc_assert (si->node_mapping[n] == n);
2022 SET_BIT (si->visited, n);
2023 si->dfs[n] = si->current_index ++;
2024 my_dfs = si->dfs[n];
2026 /* Visit all the successors. */
2027 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2029 unsigned int w = si->node_mapping[i];
2031 if (TEST_BIT (si->deleted, w))
2034 if (!TEST_BIT (si->visited, w))
2035 condense_visit (graph, si, w);
2037 unsigned int t = si->node_mapping[w];
2038 unsigned int nnode = si->node_mapping[n];
2039 gcc_assert (nnode == n);
2041 if (si->dfs[t] < si->dfs[nnode])
2042 si->dfs[n] = si->dfs[t];
2046 /* Visit all the implicit predecessors. */
2047 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2049 unsigned int w = si->node_mapping[i];
2051 if (TEST_BIT (si->deleted, w))
2054 if (!TEST_BIT (si->visited, w))
2055 condense_visit (graph, si, w);
2057 unsigned int t = si->node_mapping[w];
2058 unsigned int nnode = si->node_mapping[n];
2059 gcc_assert (nnode == n);
2061 if (si->dfs[t] < si->dfs[nnode])
2062 si->dfs[n] = si->dfs[t];
2066 /* See if any components have been identified. */
2067 if (si->dfs[n] == my_dfs)
2069 while (VEC_length (unsigned, si->scc_stack) != 0
2070 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2072 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2073 si->node_mapping[w] = n;
2075 if (!TEST_BIT (graph->direct_nodes, w))
2076 RESET_BIT (graph->direct_nodes, n);
2078 /* Unify our nodes. */
2079 if (graph->preds[w])
2081 if (!graph->preds[n])
2082 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2083 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2085 if (graph->implicit_preds[w])
2087 if (!graph->implicit_preds[n])
2088 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2089 bitmap_ior_into (graph->implicit_preds[n],
2090 graph->implicit_preds[w]);
2092 if (graph->points_to[w])
2094 if (!graph->points_to[n])
2095 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2096 bitmap_ior_into (graph->points_to[n],
2097 graph->points_to[w]);
2100 SET_BIT (si->deleted, n);
2103 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2106 /* Label pointer equivalences. */
2109 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2113 SET_BIT (si->visited, n);
2115 if (!graph->points_to[n])
2116 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2118 /* Label and union our incoming edges's points to sets. */
2119 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2121 unsigned int w = si->node_mapping[i];
2122 if (!TEST_BIT (si->visited, w))
2123 label_visit (graph, si, w);
2125 /* Skip unused edges */
2126 if (w == n || graph->pointer_label[w] == 0)
2129 if (graph->points_to[w])
2130 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2132 /* Indirect nodes get fresh variables. */
2133 if (!TEST_BIT (graph->direct_nodes, n))
2134 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2136 if (!bitmap_empty_p (graph->points_to[n]))
2138 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2139 graph->points_to[n]);
2142 label = pointer_equiv_class++;
2143 equiv_class_add (pointer_equiv_class_table,
2144 label, graph->points_to[n]);
2146 graph->pointer_label[n] = label;
2150 /* Perform offline variable substitution, discovering equivalence
2151 classes, and eliminating non-pointer variables. */
2153 static struct scc_info *
2154 perform_var_substitution (constraint_graph_t graph)
2157 unsigned int size = graph->size;
2158 struct scc_info *si = init_scc_info (size);
2160 bitmap_obstack_initialize (&iteration_obstack);
2161 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2162 equiv_class_label_eq, free);
2163 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2164 equiv_class_label_eq, free);
2165 pointer_equiv_class = 1;
2166 location_equiv_class = 1;
2168 /* Condense the nodes, which means to find SCC's, count incoming
2169 predecessors, and unite nodes in SCC's. */
2170 for (i = 0; i < FIRST_REF_NODE; i++)
2171 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2172 condense_visit (graph, si, si->node_mapping[i]);
2174 sbitmap_zero (si->visited);
2175 /* Actually the label the nodes for pointer equivalences */
2176 for (i = 0; i < FIRST_REF_NODE; i++)
2177 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2178 label_visit (graph, si, si->node_mapping[i]);
2180 /* Calculate location equivalence labels. */
2181 for (i = 0; i < FIRST_REF_NODE; i++)
2188 if (!graph->pointed_by[i])
2190 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2192 /* Translate the pointed-by mapping for pointer equivalence
2194 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2196 bitmap_set_bit (pointed_by,
2197 graph->pointer_label[si->node_mapping[j]]);
2199 /* The original pointed_by is now dead. */
2200 BITMAP_FREE (graph->pointed_by[i]);
2202 /* Look up the location equivalence label if one exists, or make
2204 label = equiv_class_lookup (location_equiv_class_table,
2208 label = location_equiv_class++;
2209 equiv_class_add (location_equiv_class_table,
2214 if (dump_file && (dump_flags & TDF_DETAILS))
2215 fprintf (dump_file, "Found location equivalence for node %s\n",
2216 get_varinfo (i)->name);
2217 BITMAP_FREE (pointed_by);
2219 graph->loc_label[i] = label;
2223 if (dump_file && (dump_flags & TDF_DETAILS))
2224 for (i = 0; i < FIRST_REF_NODE; i++)
2226 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2228 "Equivalence classes for %s node id %d:%s are pointer: %d"
2230 direct_node ? "Direct node" : "Indirect node", i,
2231 get_varinfo (i)->name,
2232 graph->pointer_label[si->node_mapping[i]],
2233 graph->loc_label[si->node_mapping[i]]);
2236 /* Quickly eliminate our non-pointer variables. */
2238 for (i = 0; i < FIRST_REF_NODE; i++)
2240 unsigned int node = si->node_mapping[i];
2242 if (graph->pointer_label[node] == 0)
2244 if (dump_file && (dump_flags & TDF_DETAILS))
2246 "%s is a non-pointer variable, eliminating edges.\n",
2247 get_varinfo (node)->name);
2248 stats.nonpointer_vars++;
2249 clear_edges_for_node (graph, node);
2256 /* Free information that was only necessary for variable
2260 free_var_substitution_info (struct scc_info *si)
2263 free (graph->pointer_label);
2264 free (graph->loc_label);
2265 free (graph->pointed_by);
2266 free (graph->points_to);
2267 free (graph->eq_rep);
2268 sbitmap_free (graph->direct_nodes);
2269 htab_delete (pointer_equiv_class_table);
2270 htab_delete (location_equiv_class_table);
2271 bitmap_obstack_release (&iteration_obstack);
2274 /* Return an existing node that is equivalent to NODE, which has
2275 equivalence class LABEL, if one exists. Return NODE otherwise. */
2278 find_equivalent_node (constraint_graph_t graph,
2279 unsigned int node, unsigned int label)
2281 /* If the address version of this variable is unused, we can
2282 substitute it for anything else with the same label.
2283 Otherwise, we know the pointers are equivalent, but not the
2284 locations, and we can unite them later. */
2286 if (!bitmap_bit_p (graph->address_taken, node))
2288 gcc_assert (label < graph->size);
2290 if (graph->eq_rep[label] != -1)
2292 /* Unify the two variables since we know they are equivalent. */
2293 if (unite (graph->eq_rep[label], node))
2294 unify_nodes (graph, graph->eq_rep[label], node, false);
2295 return graph->eq_rep[label];
2299 graph->eq_rep[label] = node;
2300 graph->pe_rep[label] = node;
2305 gcc_assert (label < graph->size);
2306 graph->pe[node] = label;
2307 if (graph->pe_rep[label] == -1)
2308 graph->pe_rep[label] = node;
2314 /* Unite pointer equivalent but not location equivalent nodes in
2315 GRAPH. This may only be performed once variable substitution is
2319 unite_pointer_equivalences (constraint_graph_t graph)
2323 /* Go through the pointer equivalences and unite them to their
2324 representative, if they aren't already. */
2325 for (i = 0; i < FIRST_REF_NODE; i++)
2327 unsigned int label = graph->pe[i];
2330 int label_rep = graph->pe_rep[label];
2332 if (label_rep == -1)
2335 label_rep = find (label_rep);
2336 if (label_rep >= 0 && unite (label_rep, find (i)))
2337 unify_nodes (graph, label_rep, i, false);
2342 /* Move complex constraints to the GRAPH nodes they belong to. */
2345 move_complex_constraints (constraint_graph_t graph)
2350 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2354 struct constraint_expr lhs = c->lhs;
2355 struct constraint_expr rhs = c->rhs;
2357 if (lhs.type == DEREF)
2359 insert_into_complex (graph, lhs.var, c);
2361 else if (rhs.type == DEREF)
2363 if (!(get_varinfo (lhs.var)->is_special_var))
2364 insert_into_complex (graph, rhs.var, c);
2366 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2367 && (lhs.offset != 0 || rhs.offset != 0))
2369 insert_into_complex (graph, rhs.var, c);
2376 /* Optimize and rewrite complex constraints while performing
2377 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2378 result of perform_variable_substitution. */
2381 rewrite_constraints (constraint_graph_t graph,
2382 struct scc_info *si)
2388 for (j = 0; j < graph->size; j++)
2389 gcc_assert (find (j) == j);
2391 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2393 struct constraint_expr lhs = c->lhs;
2394 struct constraint_expr rhs = c->rhs;
2395 unsigned int lhsvar = find (lhs.var);
2396 unsigned int rhsvar = find (rhs.var);
2397 unsigned int lhsnode, rhsnode;
2398 unsigned int lhslabel, rhslabel;
2400 lhsnode = si->node_mapping[lhsvar];
2401 rhsnode = si->node_mapping[rhsvar];
2402 lhslabel = graph->pointer_label[lhsnode];
2403 rhslabel = graph->pointer_label[rhsnode];
2405 /* See if it is really a non-pointer variable, and if so, ignore
2409 if (dump_file && (dump_flags & TDF_DETAILS))
2412 fprintf (dump_file, "%s is a non-pointer variable,"
2413 "ignoring constraint:",
2414 get_varinfo (lhs.var)->name);
2415 dump_constraint (dump_file, c);
2416 fprintf (dump_file, "\n");
2418 VEC_replace (constraint_t, constraints, i, NULL);
2424 if (dump_file && (dump_flags & TDF_DETAILS))
2427 fprintf (dump_file, "%s is a non-pointer variable,"
2428 "ignoring constraint:",
2429 get_varinfo (rhs.var)->name);
2430 dump_constraint (dump_file, c);
2431 fprintf (dump_file, "\n");
2433 VEC_replace (constraint_t, constraints, i, NULL);
2437 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2438 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2439 c->lhs.var = lhsvar;
2440 c->rhs.var = rhsvar;
2445 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2446 part of an SCC, false otherwise. */
2449 eliminate_indirect_cycles (unsigned int node)
2451 if (graph->indirect_cycles[node] != -1
2452 && !bitmap_empty_p (get_varinfo (node)->solution))
2455 VEC(unsigned,heap) *queue = NULL;
2457 unsigned int to = find (graph->indirect_cycles[node]);
2460 /* We can't touch the solution set and call unify_nodes
2461 at the same time, because unify_nodes is going to do
2462 bitmap unions into it. */
2464 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2466 if (find (i) == i && i != to)
2469 VEC_safe_push (unsigned, heap, queue, i);
2474 VEC_iterate (unsigned, queue, queuepos, i);
2477 unify_nodes (graph, to, i, true);
2479 VEC_free (unsigned, heap, queue);
2485 /* Solve the constraint graph GRAPH using our worklist solver.
2486 This is based on the PW* family of solvers from the "Efficient Field
2487 Sensitive Pointer Analysis for C" paper.
2488 It works by iterating over all the graph nodes, processing the complex
2489 constraints and propagating the copy constraints, until everything stops
2490 changed. This corresponds to steps 6-8 in the solving list given above. */
2493 solve_graph (constraint_graph_t graph)
2495 unsigned int size = graph->size;
2499 changed = BITMAP_ALLOC (NULL);
2501 /* Mark all initial non-collapsed nodes as changed. */
2502 for (i = 0; i < size; i++)
2504 varinfo_t ivi = get_varinfo (i);
2505 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2506 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2507 || VEC_length (constraint_t, graph->complex[i]) > 0))
2508 bitmap_set_bit (changed, i);
2511 /* Allocate a bitmap to be used to store the changed bits. */
2512 pts = BITMAP_ALLOC (&pta_obstack);
2514 while (!bitmap_empty_p (changed))
2517 struct topo_info *ti = init_topo_info ();
2520 bitmap_obstack_initialize (&iteration_obstack);
2522 compute_topo_order (graph, ti);
2524 while (VEC_length (unsigned, ti->topo_order) != 0)
2527 i = VEC_pop (unsigned, ti->topo_order);
2529 /* If this variable is not a representative, skip it. */
2533 /* In certain indirect cycle cases, we may merge this
2534 variable to another. */
2535 if (eliminate_indirect_cycles (i) && find (i) != i)
2538 /* If the node has changed, we need to process the
2539 complex constraints and outgoing edges again. */
2540 if (bitmap_clear_bit (changed, i))
2545 VEC(constraint_t,heap) *complex = graph->complex[i];
2546 varinfo_t vi = get_varinfo (i);
2547 bool solution_empty;
2549 /* Compute the changed set of solution bits. */
2550 if (vi->oldsolution)
2551 bitmap_and_compl (pts, vi->solution, vi->oldsolution);
2553 bitmap_copy (pts, vi->solution);
2555 if (bitmap_empty_p (pts))
2558 if (vi->oldsolution)
2559 bitmap_ior_into (vi->oldsolution, pts);
2562 vi->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
2563 bitmap_copy (vi->oldsolution, pts);
2566 solution = vi->solution;
2567 solution_empty = bitmap_empty_p (solution);
2569 /* Process the complex constraints */
2570 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2572 /* XXX: This is going to unsort the constraints in
2573 some cases, which will occasionally add duplicate
2574 constraints during unification. This does not
2575 affect correctness. */
2576 c->lhs.var = find (c->lhs.var);
2577 c->rhs.var = find (c->rhs.var);
2579 /* The only complex constraint that can change our
2580 solution to non-empty, given an empty solution,
2581 is a constraint where the lhs side is receiving
2582 some set from elsewhere. */
2583 if (!solution_empty || c->lhs.type != DEREF)
2584 do_complex_constraint (graph, c, pts);
2587 solution_empty = bitmap_empty_p (solution);
2589 if (!solution_empty)
2592 unsigned eff_escaped_id = find (escaped_id);
2594 /* Propagate solution to all successors. */
2595 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2601 unsigned int to = find (j);
2602 tmp = get_varinfo (to)->solution;
2605 /* Don't try to propagate to ourselves. */
2609 /* If we propagate from ESCAPED use ESCAPED as
2611 if (i == eff_escaped_id)
2612 flag = bitmap_set_bit (tmp, escaped_id);
2614 flag = set_union_with_increment (tmp, pts, 0);
2618 get_varinfo (to)->solution = tmp;
2619 bitmap_set_bit (changed, to);
2625 free_topo_info (ti);
2626 bitmap_obstack_release (&iteration_obstack);
2630 BITMAP_FREE (changed);
2631 bitmap_obstack_release (&oldpta_obstack);
2634 /* Map from trees to variable infos. */
2635 static struct pointer_map_t *vi_for_tree;
2638 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2641 insert_vi_for_tree (tree t, varinfo_t vi)
2643 void **slot = pointer_map_insert (vi_for_tree, t);
2645 gcc_assert (*slot == NULL);
2649 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2650 exist in the map, return NULL, otherwise, return the varinfo we found. */
2653 lookup_vi_for_tree (tree t)
2655 void **slot = pointer_map_contains (vi_for_tree, t);
2659 return (varinfo_t) *slot;
2662 /* Return a printable name for DECL */
2665 alias_get_name (tree decl)
2669 int num_printed = 0;
2671 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2672 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2674 res= get_name (decl);
2682 if (TREE_CODE (decl) == SSA_NAME)
2684 num_printed = asprintf (&temp, "%s_%u",
2685 alias_get_name (SSA_NAME_VAR (decl)),
2686 SSA_NAME_VERSION (decl));
2688 else if (DECL_P (decl))
2690 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2692 if (num_printed > 0)
2694 res = ggc_strdup (temp);
2700 /* Find the variable id for tree T in the map.
2701 If T doesn't exist in the map, create an entry for it and return it. */
2704 get_vi_for_tree (tree t)
2706 void **slot = pointer_map_contains (vi_for_tree, t);
2708 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2710 return (varinfo_t) *slot;
2713 /* Get a scalar constraint expression for a new temporary variable. */
2715 static struct constraint_expr
2716 new_scalar_tmp_constraint_exp (const char *name)
2718 struct constraint_expr tmp;
2721 vi = new_var_info (NULL_TREE, name);
2725 vi->is_full_var = 1;
2734 /* Get a constraint expression vector from an SSA_VAR_P node.
2735 If address_p is true, the result will be taken its address of. */
2738 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2740 struct constraint_expr cexpr;
2743 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2744 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2746 /* For parameters, get at the points-to set for the actual parm
2748 if (TREE_CODE (t) == SSA_NAME
2749 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2750 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2751 && SSA_NAME_IS_DEFAULT_DEF (t))
2753 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2757 /* For global variables resort to the alias target. */
2758 if (TREE_CODE (t) == VAR_DECL
2759 && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
2761 struct varpool_node *node = varpool_get_node (t);
2762 if (node && node->alias)
2764 node = varpool_variable_node (node, NULL);
2769 vi = get_vi_for_tree (t);
2771 cexpr.type = SCALAR;
2773 /* If we determine the result is "anything", and we know this is readonly,
2774 say it points to readonly memory instead. */
2775 if (cexpr.var == anything_id && TREE_READONLY (t))
2778 cexpr.type = ADDRESSOF;
2779 cexpr.var = readonly_id;
2782 /* If we are not taking the address of the constraint expr, add all
2783 sub-fiels of the variable as well. */
2785 && !vi->is_full_var)
2787 for (; vi; vi = vi->next)
2790 VEC_safe_push (ce_s, heap, *results, &cexpr);
2795 VEC_safe_push (ce_s, heap, *results, &cexpr);
2798 /* Process constraint T, performing various simplifications and then
2799 adding it to our list of overall constraints. */
2802 process_constraint (constraint_t t)
2804 struct constraint_expr rhs = t->rhs;
2805 struct constraint_expr lhs = t->lhs;
2807 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2808 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2810 /* If we didn't get any useful constraint from the lhs we get
2811 &ANYTHING as fallback from get_constraint_for. Deal with
2812 it here by turning it into *ANYTHING. */
2813 if (lhs.type == ADDRESSOF
2814 && lhs.var == anything_id)
2817 /* ADDRESSOF on the lhs is invalid. */
2818 gcc_assert (lhs.type != ADDRESSOF);
2820 /* We shouldn't add constraints from things that cannot have pointers.
2821 It's not completely trivial to avoid in the callers, so do it here. */
2822 if (rhs.type != ADDRESSOF
2823 && !get_varinfo (rhs.var)->may_have_pointers)
2826 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2827 if (!get_varinfo (lhs.var)->may_have_pointers)
2830 /* This can happen in our IR with things like n->a = *p */
2831 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2833 /* Split into tmp = *rhs, *lhs = tmp */
2834 struct constraint_expr tmplhs;
2835 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2836 process_constraint (new_constraint (tmplhs, rhs));
2837 process_constraint (new_constraint (lhs, tmplhs));
2839 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2841 /* Split into tmp = &rhs, *lhs = tmp */
2842 struct constraint_expr tmplhs;
2843 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2844 process_constraint (new_constraint (tmplhs, rhs));
2845 process_constraint (new_constraint (lhs, tmplhs));
2849 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2850 VEC_safe_push (constraint_t, heap, constraints, t);
2855 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2858 static HOST_WIDE_INT
2859 bitpos_of_field (const tree fdecl)
2861 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2862 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2865 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2866 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2870 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2871 resulting constraint expressions in *RESULTS. */
2874 get_constraint_for_ptr_offset (tree ptr, tree offset,
2875 VEC (ce_s, heap) **results)
2877 struct constraint_expr c;
2879 HOST_WIDE_INT rhsoffset;
2881 /* If we do not do field-sensitive PTA adding offsets to pointers
2882 does not change the points-to solution. */
2883 if (!use_field_sensitive)
2885 get_constraint_for_rhs (ptr, results);
2889 /* If the offset is not a non-negative integer constant that fits
2890 in a HOST_WIDE_INT, we have to fall back to a conservative
2891 solution which includes all sub-fields of all pointed-to
2892 variables of ptr. */
2893 if (offset == NULL_TREE
2894 || TREE_CODE (offset) != INTEGER_CST)
2895 rhsoffset = UNKNOWN_OFFSET;
2898 /* Sign-extend the offset. */
2900 = double_int_sext (tree_to_double_int (offset),
2901 TYPE_PRECISION (TREE_TYPE (offset)));
2902 if (!double_int_fits_in_shwi_p (soffset))
2903 rhsoffset = UNKNOWN_OFFSET;
2906 /* Make sure the bit-offset also fits. */
2907 HOST_WIDE_INT rhsunitoffset = soffset.low;
2908 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2909 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2910 rhsoffset = UNKNOWN_OFFSET;
2914 get_constraint_for_rhs (ptr, results);
2918 /* As we are eventually appending to the solution do not use
2919 VEC_iterate here. */
2920 n = VEC_length (ce_s, *results);
2921 for (j = 0; j < n; j++)
2924 c = *VEC_index (ce_s, *results, j);
2925 curr = get_varinfo (c.var);
2927 if (c.type == ADDRESSOF
2928 /* If this varinfo represents a full variable just use it. */
2929 && curr->is_full_var)
2931 else if (c.type == ADDRESSOF
2932 /* If we do not know the offset add all subfields. */
2933 && rhsoffset == UNKNOWN_OFFSET)
2935 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2938 struct constraint_expr c2;
2940 c2.type = ADDRESSOF;
2942 if (c2.var != c.var)
2943 VEC_safe_push (ce_s, heap, *results, &c2);
2948 else if (c.type == ADDRESSOF)
2951 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2953 /* Search the sub-field which overlaps with the
2954 pointed-to offset. If the result is outside of the variable
2955 we have to provide a conservative result, as the variable is
2956 still reachable from the resulting pointer (even though it
2957 technically cannot point to anything). The last and first
2958 sub-fields are such conservative results.
2959 ??? If we always had a sub-field for &object + 1 then
2960 we could represent this in a more precise way. */
2962 && curr->offset < offset)
2964 temp = first_or_preceding_vi_for_offset (curr, offset);
2966 /* If the found variable is not exactly at the pointed to
2967 result, we have to include the next variable in the
2968 solution as well. Otherwise two increments by offset / 2
2969 do not result in the same or a conservative superset
2971 if (temp->offset != offset
2972 && temp->next != NULL)
2974 struct constraint_expr c2;
2975 c2.var = temp->next->id;
2976 c2.type = ADDRESSOF;
2978 VEC_safe_push (ce_s, heap, *results, &c2);
2984 c.offset = rhsoffset;
2986 VEC_replace (ce_s, *results, j, &c);
2991 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2992 If address_p is true the result will be taken its address of.
2993 If lhs_p is true then the constraint expression is assumed to be used
2997 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2998 bool address_p, bool lhs_p)
3001 HOST_WIDE_INT bitsize = -1;
3002 HOST_WIDE_INT bitmaxsize = -1;
3003 HOST_WIDE_INT bitpos;
3005 struct constraint_expr *result;
3007 /* Some people like to do cute things like take the address of
3010 while (handled_component_p (forzero)
3011 || INDIRECT_REF_P (forzero)
3012 || TREE_CODE (forzero) == MEM_REF)
3013 forzero = TREE_OPERAND (forzero, 0);
3015 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3017 struct constraint_expr temp;
3020 temp.var = integer_id;
3022 VEC_safe_push (ce_s, heap, *results, &temp);
3026 /* Handle type-punning through unions. If we are extracting a pointer
3027 from a union via a possibly type-punning access that pointer
3028 points to anything, similar to a conversion of an integer to
3034 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3035 u = TREE_OPERAND (u, 0))
3036 if (TREE_CODE (u) == COMPONENT_REF
3037 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3039 struct constraint_expr temp;
3042 temp.var = anything_id;
3043 temp.type = ADDRESSOF;
3044 VEC_safe_push (ce_s, heap, *results, &temp);
3049 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3051 /* Pretend to take the address of the base, we'll take care of
3052 adding the required subset of sub-fields below. */
3053 get_constraint_for_1 (t, results, true, lhs_p);
3054 gcc_assert (VEC_length (ce_s, *results) == 1);
3055 result = VEC_last (ce_s, *results);
3057 if (result->type == SCALAR
3058 && get_varinfo (result->var)->is_full_var)
3059 /* For single-field vars do not bother about the offset. */
3061 else if (result->type == SCALAR)
3063 /* In languages like C, you can access one past the end of an
3064 array. You aren't allowed to dereference it, so we can
3065 ignore this constraint. When we handle pointer subtraction,
3066 we may have to do something cute here. */
3068 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3071 /* It's also not true that the constraint will actually start at the
3072 right offset, it may start in some padding. We only care about
3073 setting the constraint to the first actual field it touches, so
3075 struct constraint_expr cexpr = *result;
3077 VEC_pop (ce_s, *results);
3079 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3081 if (ranges_overlap_p (curr->offset, curr->size,
3082 bitpos, bitmaxsize))
3084 cexpr.var = curr->id;
3085 VEC_safe_push (ce_s, heap, *results, &cexpr);
3090 /* If we are going to take the address of this field then
3091 to be able to compute reachability correctly add at least
3092 the last field of the variable. */
3094 && VEC_length (ce_s, *results) == 0)
3096 curr = get_varinfo (cexpr.var);
3097 while (curr->next != NULL)
3099 cexpr.var = curr->id;
3100 VEC_safe_push (ce_s, heap, *results, &cexpr);
3102 else if (VEC_length (ce_s, *results) == 0)
3103 /* Assert that we found *some* field there. The user couldn't be
3104 accessing *only* padding. */
3105 /* Still the user could access one past the end of an array
3106 embedded in a struct resulting in accessing *only* padding. */
3107 /* Or accessing only padding via type-punning to a type
3108 that has a filed just in padding space. */
3110 cexpr.type = SCALAR;
3111 cexpr.var = anything_id;
3113 VEC_safe_push (ce_s, heap, *results, &cexpr);
3116 else if (bitmaxsize == 0)
3118 if (dump_file && (dump_flags & TDF_DETAILS))
3119 fprintf (dump_file, "Access to zero-sized part of variable,"
3123 if (dump_file && (dump_flags & TDF_DETAILS))
3124 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3126 else if (result->type == DEREF)
3128 /* If we do not know exactly where the access goes say so. Note
3129 that only for non-structure accesses we know that we access
3130 at most one subfiled of any variable. */
3132 || bitsize != bitmaxsize
3133 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3134 || result->offset == UNKNOWN_OFFSET)
3135 result->offset = UNKNOWN_OFFSET;
3137 result->offset += bitpos;
3139 else if (result->type == ADDRESSOF)
3141 /* We can end up here for component references on a
3142 VIEW_CONVERT_EXPR <>(&foobar). */
3143 result->type = SCALAR;
3144 result->var = anything_id;
3152 /* Dereference the constraint expression CONS, and return the result.
3153 DEREF (ADDRESSOF) = SCALAR
3154 DEREF (SCALAR) = DEREF
3155 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3156 This is needed so that we can handle dereferencing DEREF constraints. */
3159 do_deref (VEC (ce_s, heap) **constraints)
3161 struct constraint_expr *c;
3164 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3166 if (c->type == SCALAR)
3168 else if (c->type == ADDRESSOF)
3170 else if (c->type == DEREF)
3172 struct constraint_expr tmplhs;
3173 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3174 process_constraint (new_constraint (tmplhs, *c));
3175 c->var = tmplhs.var;
3182 /* Given a tree T, return the constraint expression for taking the
3186 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3188 struct constraint_expr *c;
3191 get_constraint_for_1 (t, results, true, true);
3193 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3195 if (c->type == DEREF)
3198 c->type = ADDRESSOF;
3202 /* Given a tree T, return the constraint expression for it. */
3205 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3208 struct constraint_expr temp;
3210 /* x = integer is all glommed to a single variable, which doesn't
3211 point to anything by itself. That is, of course, unless it is an
3212 integer constant being treated as a pointer, in which case, we
3213 will return that this is really the addressof anything. This
3214 happens below, since it will fall into the default case. The only
3215 case we know something about an integer treated like a pointer is
3216 when it is the NULL pointer, and then we just say it points to
3219 Do not do that if -fno-delete-null-pointer-checks though, because
3220 in that case *NULL does not fail, so it _should_ alias *anything.
3221 It is not worth adding a new option or renaming the existing one,
3222 since this case is relatively obscure. */
3223 if ((TREE_CODE (t) == INTEGER_CST
3224 && integer_zerop (t))
3225 /* The only valid CONSTRUCTORs in gimple with pointer typed
3226 elements are zero-initializer. But in IPA mode we also
3227 process global initializers, so verify at least. */
3228 || (TREE_CODE (t) == CONSTRUCTOR
3229 && CONSTRUCTOR_NELTS (t) == 0))
3231 if (flag_delete_null_pointer_checks)
3232 temp.var = nothing_id;
3234 temp.var = nonlocal_id;
3235 temp.type = ADDRESSOF;
3237 VEC_safe_push (ce_s, heap, *results, &temp);
3241 /* String constants are read-only. */
3242 if (TREE_CODE (t) == STRING_CST)
3244 temp.var = readonly_id;
3247 VEC_safe_push (ce_s, heap, *results, &temp);
3251 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3253 case tcc_expression:
3255 switch (TREE_CODE (t))
3258 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3266 switch (TREE_CODE (t))
3270 struct constraint_expr cs;
3272 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
3273 TREE_OPERAND (t, 1), results);
3276 /* If we are not taking the address then make sure to process
3277 all subvariables we might access. */
3281 cs = *VEC_last (ce_s, *results);
3282 if (cs.type == DEREF)
3284 /* For dereferences this means we have to defer it
3286 VEC_last (ce_s, *results)->offset = UNKNOWN_OFFSET;
3289 if (cs.type != SCALAR)
3292 vi = get_varinfo (cs.var);
3294 if (!vi->is_full_var
3297 unsigned HOST_WIDE_INT size;
3298 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3299 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3302 for (; curr; curr = curr->next)
3304 if (curr->offset - vi->offset < size)
3307 VEC_safe_push (ce_s, heap, *results, &cs);
3316 case ARRAY_RANGE_REF:
3318 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3320 case VIEW_CONVERT_EXPR:
3321 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3324 /* We are missing handling for TARGET_MEM_REF here. */
3329 case tcc_exceptional:
3331 switch (TREE_CODE (t))
3335 get_constraint_for_ssa_var (t, results, address_p);
3342 VEC (ce_s, heap) *tmp = NULL;
3343 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3345 struct constraint_expr *rhsp;
3347 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3348 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3349 VEC_safe_push (ce_s, heap, *results, rhsp);
3350 VEC_truncate (ce_s, tmp, 0);
3352 VEC_free (ce_s, heap, tmp);
3353 /* We do not know whether the constructor was complete,
3354 so technically we have to add &NOTHING or &ANYTHING
3355 like we do for an empty constructor as well. */
3362 case tcc_declaration:
3364 get_constraint_for_ssa_var (t, results, address_p);
3369 /* We cannot refer to automatic variables through constants. */
3370 temp.type = ADDRESSOF;
3371 temp.var = nonlocal_id;
3373 VEC_safe_push (ce_s, heap, *results, &temp);
3379 /* The default fallback is a constraint from anything. */
3380 temp.type = ADDRESSOF;
3381 temp.var = anything_id;
3383 VEC_safe_push (ce_s, heap, *results, &temp);
3386 /* Given a gimple tree T, return the constraint expression vector for it. */
3389 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3391 gcc_assert (VEC_length (ce_s, *results) == 0);
3393 get_constraint_for_1 (t, results, false, true);
3396 /* Given a gimple tree T, return the constraint expression vector for it
3397 to be used as the rhs of a constraint. */
3400 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3402 gcc_assert (VEC_length (ce_s, *results) == 0);
3404 get_constraint_for_1 (t, results, false, false);
3408 /* Efficiently generates constraints from all entries in *RHSC to all
3409 entries in *LHSC. */
3412 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3414 struct constraint_expr *lhsp, *rhsp;
3417 if (VEC_length (ce_s, lhsc) <= 1
3418 || VEC_length (ce_s, rhsc) <= 1)
3420 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3421 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3422 process_constraint (new_constraint (*lhsp, *rhsp));
3426 struct constraint_expr tmp;
3427 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3428 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3429 process_constraint (new_constraint (tmp, *rhsp));
3430 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3431 process_constraint (new_constraint (*lhsp, tmp));
3435 /* Handle aggregate copies by expanding into copies of the respective
3436 fields of the structures. */
3439 do_structure_copy (tree lhsop, tree rhsop)
3441 struct constraint_expr *lhsp, *rhsp;
3442 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3445 get_constraint_for (lhsop, &lhsc);
3446 get_constraint_for_rhs (rhsop, &rhsc);
3447 lhsp = VEC_index (ce_s, lhsc, 0);
3448 rhsp = VEC_index (ce_s, rhsc, 0);
3449 if (lhsp->type == DEREF
3450 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3451 || rhsp->type == DEREF)
3453 if (lhsp->type == DEREF)
3455 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3456 lhsp->offset = UNKNOWN_OFFSET;
3458 if (rhsp->type == DEREF)
3460 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3461 rhsp->offset = UNKNOWN_OFFSET;
3463 process_all_all_constraints (lhsc, rhsc);
3465 else if (lhsp->type == SCALAR
3466 && (rhsp->type == SCALAR
3467 || rhsp->type == ADDRESSOF))
3469 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3470 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3472 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3473 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3474 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3476 varinfo_t lhsv, rhsv;
3477 rhsp = VEC_index (ce_s, rhsc, k);
3478 lhsv = get_varinfo (lhsp->var);
3479 rhsv = get_varinfo (rhsp->var);
3480 if (lhsv->may_have_pointers
3481 && (lhsv->is_full_var
3482 || rhsv->is_full_var
3483 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3484 rhsv->offset + lhsoffset, rhsv->size)))
3485 process_constraint (new_constraint (*lhsp, *rhsp));
3486 if (!rhsv->is_full_var
3487 && (lhsv->is_full_var
3488 || (lhsv->offset + rhsoffset + lhsv->size
3489 > rhsv->offset + lhsoffset + rhsv->size)))
3492 if (k >= VEC_length (ce_s, rhsc))
3502 VEC_free (ce_s, heap, lhsc);
3503 VEC_free (ce_s, heap, rhsc);
3506 /* Create constraints ID = { rhsc }. */
3509 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3511 struct constraint_expr *c;
3512 struct constraint_expr includes;
3516 includes.offset = 0;
3517 includes.type = SCALAR;
3519 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3520 process_constraint (new_constraint (includes, *c));
3523 /* Create a constraint ID = OP. */
3526 make_constraint_to (unsigned id, tree op)
3528 VEC(ce_s, heap) *rhsc = NULL;
3529 get_constraint_for_rhs (op, &rhsc);
3530 make_constraints_to (id, rhsc);
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 /* Temporary storage for fake var decls. */
3603 struct obstack fake_var_decl_obstack;
3605 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
3608 build_fake_var_decl (tree type)
3610 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
3611 memset (decl, 0, sizeof (struct tree_var_decl));
3612 TREE_SET_CODE (decl, VAR_DECL);
3613 TREE_TYPE (decl) = type;
3614 DECL_UID (decl) = allocate_decl_uid ();
3615 SET_DECL_PT_UID (decl, -1);
3616 layout_decl (decl, 0);
3620 /* Create a new artificial heap variable with NAME.
3621 Return the created variable. */
3624 make_heapvar (const char *name)
3629 heapvar = build_fake_var_decl (ptr_type_node);
3630 DECL_EXTERNAL (heapvar) = 1;
3632 vi = new_var_info (heapvar, name);
3633 vi->is_artificial_var = true;
3634 vi->is_heap_var = true;
3635 vi->is_unknown_size_var = true;
3639 vi->is_full_var = true;
3640 insert_vi_for_tree (heapvar, vi);
3645 /* Create a new artificial heap variable with NAME and make a
3646 constraint from it to LHS. Return the created variable. */
3649 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3651 varinfo_t vi = make_heapvar (name);
3652 make_constraint_from (lhs, vi->id);
3657 /* Create a new artificial heap variable with NAME and make a
3658 constraint from it to LHS. Set flags according to a tag used
3659 for tracking restrict pointers. */
3662 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3665 vi = make_constraint_from_heapvar (lhs, name);
3666 vi->is_restrict_var = 1;
3667 vi->is_global_var = 0;
3668 vi->is_special_var = 1;
3669 vi->may_have_pointers = 0;
3672 /* In IPA mode there are varinfos for different aspects of reach
3673 function designator. One for the points-to set of the return
3674 value, one for the variables that are clobbered by the function,
3675 one for its uses and one for each parameter (including a single
3676 glob for remaining variadic arguments). */
3678 enum { fi_clobbers = 1, fi_uses = 2,
3679 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3681 /* Get a constraint for the requested part of a function designator FI
3682 when operating in IPA mode. */
3684 static struct constraint_expr
3685 get_function_part_constraint (varinfo_t fi, unsigned part)
3687 struct constraint_expr c;
3689 gcc_assert (in_ipa_mode);
3691 if (fi->id == anything_id)
3693 /* ??? We probably should have a ANYFN special variable. */
3694 c.var = anything_id;
3698 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3700 varinfo_t ai = first_vi_for_offset (fi, part);
3704 c.var = anything_id;
3718 /* For non-IPA mode, generate constraints necessary for a call on the
3722 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3724 struct constraint_expr rhsc;
3726 bool returns_uses = false;
3728 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3730 tree arg = gimple_call_arg (stmt, i);
3731 int flags = gimple_call_arg_flags (stmt, i);
3733 /* If the argument is not used we can ignore it. */
3734 if (flags & EAF_UNUSED)
3737 /* As we compute ESCAPED context-insensitive we do not gain
3738 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3739 set. The argument would still get clobbered through the
3741 ??? We might get away with less (and more precise) constraints
3742 if using a temporary for transitively closing things. */
3743 if ((flags & EAF_NOCLOBBER)
3744 && (flags & EAF_NOESCAPE))
3746 varinfo_t uses = get_call_use_vi (stmt);
3747 if (!(flags & EAF_DIRECT))
3748 make_transitive_closure_constraints (uses);
3749 make_constraint_to (uses->id, arg);
3750 returns_uses = true;
3752 else if (flags & EAF_NOESCAPE)
3754 varinfo_t uses = get_call_use_vi (stmt);
3755 varinfo_t clobbers = get_call_clobber_vi (stmt);
3756 if (!(flags & EAF_DIRECT))
3758 make_transitive_closure_constraints (uses);
3759 make_transitive_closure_constraints (clobbers);
3761 make_constraint_to (uses->id, arg);
3762 make_constraint_to (clobbers->id, arg);
3763 returns_uses = true;
3766 make_escape_constraint (arg);
3769 /* If we added to the calls uses solution make sure we account for
3770 pointers to it to be returned. */
3773 rhsc.var = get_call_use_vi (stmt)->id;
3776 VEC_safe_push (ce_s, heap, *results, &rhsc);
3779 /* The static chain escapes as well. */
3780 if (gimple_call_chain (stmt))
3781 make_escape_constraint (gimple_call_chain (stmt));
3783 /* And if we applied NRV the address of the return slot escapes as well. */
3784 if (gimple_call_return_slot_opt_p (stmt)
3785 && gimple_call_lhs (stmt) != NULL_TREE
3786 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3788 VEC(ce_s, heap) *tmpc = NULL;
3789 struct constraint_expr lhsc, *c;
3790 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3791 lhsc.var = escaped_id;
3794 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3795 process_constraint (new_constraint (lhsc, *c));
3796 VEC_free(ce_s, heap, tmpc);
3799 /* Regular functions return nonlocal memory. */
3800 rhsc.var = nonlocal_id;
3803 VEC_safe_push (ce_s, heap, *results, &rhsc);
3806 /* For non-IPA mode, generate constraints necessary for a call
3807 that returns a pointer and assigns it to LHS. This simply makes
3808 the LHS point to global and escaped variables. */
3811 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3814 VEC(ce_s, heap) *lhsc = NULL;
3816 get_constraint_for (lhs, &lhsc);
3817 /* If the store is to a global decl make sure to
3818 add proper escape constraints. */
3819 lhs = get_base_address (lhs);
3822 && is_global_var (lhs))
3824 struct constraint_expr tmpc;
3825 tmpc.var = escaped_id;
3828 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3831 /* If the call returns an argument unmodified override the rhs
3833 flags = gimple_call_return_flags (stmt);
3834 if (flags & ERF_RETURNS_ARG
3835 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3839 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3840 get_constraint_for (arg, &rhsc);
3841 process_all_all_constraints (lhsc, rhsc);
3842 VEC_free (ce_s, heap, rhsc);
3844 else if (flags & ERF_NOALIAS)
3847 struct constraint_expr tmpc;
3849 vi = make_heapvar ("HEAP");
3850 /* We delay marking allocated storage global until we know if
3852 DECL_EXTERNAL (vi->decl) = 0;
3853 vi->is_global_var = 0;
3854 /* If this is not a real malloc call assume the memory was
3855 initialized and thus may point to global memory. All
3856 builtin functions with the malloc attribute behave in a sane way. */
3858 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3859 make_constraint_from (vi, nonlocal_id);
3862 tmpc.type = ADDRESSOF;
3863 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3866 process_all_all_constraints (lhsc, rhsc);
3868 VEC_free (ce_s, heap, lhsc);
3871 /* For non-IPA mode, generate constraints necessary for a call of a
3872 const function that returns a pointer in the statement STMT. */
3875 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3877 struct constraint_expr rhsc;
3880 /* Treat nested const functions the same as pure functions as far
3881 as the static chain is concerned. */
3882 if (gimple_call_chain (stmt))
3884 varinfo_t uses = get_call_use_vi (stmt);
3885 make_transitive_closure_constraints (uses);
3886 make_constraint_to (uses->id, gimple_call_chain (stmt));
3887 rhsc.var = uses->id;
3890 VEC_safe_push (ce_s, heap, *results, &rhsc);
3893 /* May return arguments. */
3894 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3896 tree arg = gimple_call_arg (stmt, k);
3897 VEC(ce_s, heap) *argc = NULL;
3899 struct constraint_expr *argp;
3900 get_constraint_for_rhs (arg, &argc);
3901 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3902 VEC_safe_push (ce_s, heap, *results, argp);
3903 VEC_free(ce_s, heap, argc);
3906 /* May return addresses of globals. */
3907 rhsc.var = nonlocal_id;
3909 rhsc.type = ADDRESSOF;
3910 VEC_safe_push (ce_s, heap, *results, &rhsc);
3913 /* For non-IPA mode, generate constraints necessary for a call to a
3914 pure function in statement STMT. */
3917 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3919 struct constraint_expr rhsc;
3921 varinfo_t uses = NULL;
3923 /* Memory reached from pointer arguments is call-used. */
3924 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3926 tree arg = gimple_call_arg (stmt, i);
3929 uses = get_call_use_vi (stmt);
3930 make_transitive_closure_constraints (uses);
3932 make_constraint_to (uses->id, arg);
3935 /* The static chain is used as well. */
3936 if (gimple_call_chain (stmt))
3940 uses = get_call_use_vi (stmt);
3941 make_transitive_closure_constraints (uses);
3943 make_constraint_to (uses->id, gimple_call_chain (stmt));
3946 /* Pure functions may return call-used and nonlocal memory. */
3949 rhsc.var = uses->id;
3952 VEC_safe_push (ce_s, heap, *results, &rhsc);
3954 rhsc.var = nonlocal_id;
3957 VEC_safe_push (ce_s, heap, *results, &rhsc);
3961 /* Return the varinfo for the callee of CALL. */
3964 get_fi_for_callee (gimple call)
3966 tree decl, fn = gimple_call_fn (call);
3968 if (fn && TREE_CODE (fn) == OBJ_TYPE_REF)
3969 fn = OBJ_TYPE_REF_EXPR (fn);
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_addr_fndecl (fn);
3976 return get_vi_for_tree (decl);
3978 /* If the function is anything other than a SSA name pointer we have no
3979 clue and should be getting ANYFN (well, ANYTHING for now). */
3980 if (!fn || TREE_CODE (fn) != SSA_NAME)
3981 return get_varinfo (anything_id);
3983 if ((TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL
3984 || TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL)
3985 && SSA_NAME_IS_DEFAULT_DEF (fn))
3986 fn = SSA_NAME_VAR (fn);
3988 return get_vi_for_tree (fn);
3991 /* Create constraints for the builtin call T. Return true if the call
3992 was handled, otherwise false. */
3995 find_func_aliases_for_builtin_call (gimple t)
3997 tree fndecl = gimple_call_fndecl (t);
3998 VEC(ce_s, heap) *lhsc = NULL;
3999 VEC(ce_s, heap) *rhsc = NULL;
4002 if (fndecl != NULL_TREE
4003 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4004 /* ??? All builtins that are handled here need to be handled
4005 in the alias-oracle query functions explicitly! */
4006 switch (DECL_FUNCTION_CODE (fndecl))
4008 /* All the following functions return a pointer to the same object
4009 as their first argument points to. The functions do not add
4010 to the ESCAPED solution. The functions make the first argument
4011 pointed to memory point to what the second argument pointed to
4012 memory points to. */
4013 case BUILT_IN_STRCPY:
4014 case BUILT_IN_STRNCPY:
4015 case BUILT_IN_BCOPY:
4016 case BUILT_IN_MEMCPY:
4017 case BUILT_IN_MEMMOVE:
4018 case BUILT_IN_MEMPCPY:
4019 case BUILT_IN_STPCPY:
4020 case BUILT_IN_STPNCPY:
4021 case BUILT_IN_STRCAT:
4022 case BUILT_IN_STRNCAT:
4023 case BUILT_IN_STRCPY_CHK:
4024 case BUILT_IN_STRNCPY_CHK:
4025 case BUILT_IN_MEMCPY_CHK:
4026 case BUILT_IN_MEMMOVE_CHK:
4027 case BUILT_IN_MEMPCPY_CHK:
4028 case BUILT_IN_STPCPY_CHK:
4029 case BUILT_IN_STRCAT_CHK:
4030 case BUILT_IN_STRNCAT_CHK:
4032 tree res = gimple_call_lhs (t);
4033 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4034 == BUILT_IN_BCOPY ? 1 : 0));
4035 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4036 == BUILT_IN_BCOPY ? 0 : 1));
4037 if (res != NULL_TREE)
4039 get_constraint_for (res, &lhsc);
4040 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4041 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4042 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY
4043 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHK
4044 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY_CHK)
4045 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4047 get_constraint_for (dest, &rhsc);
4048 process_all_all_constraints (lhsc, rhsc);
4049 VEC_free (ce_s, heap, lhsc);
4050 VEC_free (ce_s, heap, rhsc);
4052 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4053 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4056 process_all_all_constraints (lhsc, rhsc);
4057 VEC_free (ce_s, heap, lhsc);
4058 VEC_free (ce_s, heap, rhsc);
4061 case BUILT_IN_MEMSET:
4062 case BUILT_IN_MEMSET_CHK:
4064 tree res = gimple_call_lhs (t);
4065 tree dest = gimple_call_arg (t, 0);
4068 struct constraint_expr ac;
4069 if (res != NULL_TREE)
4071 get_constraint_for (res, &lhsc);
4072 get_constraint_for (dest, &rhsc);
4073 process_all_all_constraints (lhsc, rhsc);
4074 VEC_free (ce_s, heap, lhsc);
4075 VEC_free (ce_s, heap, rhsc);
4077 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4079 if (flag_delete_null_pointer_checks
4080 && integer_zerop (gimple_call_arg (t, 1)))
4082 ac.type = ADDRESSOF;
4083 ac.var = nothing_id;
4088 ac.var = integer_id;
4091 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4092 process_constraint (new_constraint (*lhsp, ac));
4093 VEC_free (ce_s, heap, lhsc);
4096 case BUILT_IN_ASSUME_ALIGNED:
4098 tree res = gimple_call_lhs (t);
4099 tree dest = gimple_call_arg (t, 0);
4100 if (res != NULL_TREE)
4102 get_constraint_for (res, &lhsc);
4103 get_constraint_for (dest, &rhsc);
4104 process_all_all_constraints (lhsc, rhsc);
4105 VEC_free (ce_s, heap, lhsc);
4106 VEC_free (ce_s, heap, rhsc);
4110 /* All the following functions do not return pointers, do not
4111 modify the points-to sets of memory reachable from their
4112 arguments and do not add to the ESCAPED solution. */
4113 case BUILT_IN_SINCOS:
4114 case BUILT_IN_SINCOSF:
4115 case BUILT_IN_SINCOSL:
4116 case BUILT_IN_FREXP:
4117 case BUILT_IN_FREXPF:
4118 case BUILT_IN_FREXPL:
4119 case BUILT_IN_GAMMA_R:
4120 case BUILT_IN_GAMMAF_R:
4121 case BUILT_IN_GAMMAL_R:
4122 case BUILT_IN_LGAMMA_R:
4123 case BUILT_IN_LGAMMAF_R:
4124 case BUILT_IN_LGAMMAL_R:
4126 case BUILT_IN_MODFF:
4127 case BUILT_IN_MODFL:
4128 case BUILT_IN_REMQUO:
4129 case BUILT_IN_REMQUOF:
4130 case BUILT_IN_REMQUOL:
4133 case BUILT_IN_STRDUP:
4134 case BUILT_IN_STRNDUP:
4135 if (gimple_call_lhs (t))
4137 handle_lhs_call (t, gimple_call_lhs (t), gimple_call_flags (t),
4139 get_constraint_for_ptr_offset (gimple_call_lhs (t),
4141 get_constraint_for_ptr_offset (gimple_call_arg (t, 0),
4145 process_all_all_constraints (lhsc, rhsc);
4146 VEC_free (ce_s, heap, lhsc);
4147 VEC_free (ce_s, heap, rhsc);
4151 /* Trampolines are special - they set up passing the static
4153 case BUILT_IN_INIT_TRAMPOLINE:
4155 tree tramp = gimple_call_arg (t, 0);
4156 tree nfunc = gimple_call_arg (t, 1);
4157 tree frame = gimple_call_arg (t, 2);
4159 struct constraint_expr lhs, *rhsp;
4162 varinfo_t nfi = NULL;
4163 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4164 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4167 lhs = get_function_part_constraint (nfi, fi_static_chain);
4168 get_constraint_for (frame, &rhsc);
4169 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4170 process_constraint (new_constraint (lhs, *rhsp));
4171 VEC_free (ce_s, heap, rhsc);
4173 /* Make the frame point to the function for
4174 the trampoline adjustment call. */
4175 get_constraint_for (tramp, &lhsc);
4177 get_constraint_for (nfunc, &rhsc);
4178 process_all_all_constraints (lhsc, rhsc);
4179 VEC_free (ce_s, heap, rhsc);
4180 VEC_free (ce_s, heap, lhsc);
4185 /* Else fallthru to generic handling which will let
4186 the frame escape. */
4189 case BUILT_IN_ADJUST_TRAMPOLINE:
4191 tree tramp = gimple_call_arg (t, 0);
4192 tree res = gimple_call_lhs (t);
4193 if (in_ipa_mode && res)
4195 get_constraint_for (res, &lhsc);
4196 get_constraint_for (tramp, &rhsc);
4198 process_all_all_constraints (lhsc, rhsc);
4199 VEC_free (ce_s, heap, rhsc);
4200 VEC_free (ce_s, heap, lhsc);
4204 /* Variadic argument handling needs to be handled in IPA
4206 case BUILT_IN_VA_START:
4208 tree valist = gimple_call_arg (t, 0);
4209 struct constraint_expr rhs, *lhsp;
4211 get_constraint_for (valist, &lhsc);
4213 /* The va_list gets access to pointers in variadic
4214 arguments. Which we know in the case of IPA analysis
4215 and otherwise are just all nonlocal variables. */
4218 fi = lookup_vi_for_tree (cfun->decl);
4219 rhs = get_function_part_constraint (fi, ~0);
4220 rhs.type = ADDRESSOF;
4224 rhs.var = nonlocal_id;
4225 rhs.type = ADDRESSOF;
4228 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4229 process_constraint (new_constraint (*lhsp, rhs));
4230 VEC_free (ce_s, heap, lhsc);
4231 /* va_list is clobbered. */
4232 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4235 /* va_end doesn't have any effect that matters. */
4236 case BUILT_IN_VA_END:
4238 /* Alternate return. Simply give up for now. */
4239 case BUILT_IN_RETURN:
4243 || !(fi = get_vi_for_tree (cfun->decl)))
4244 make_constraint_from (get_varinfo (escaped_id), anything_id);
4245 else if (in_ipa_mode
4248 struct constraint_expr lhs, rhs;
4249 lhs = get_function_part_constraint (fi, fi_result);
4250 rhs.var = anything_id;
4253 process_constraint (new_constraint (lhs, rhs));
4257 /* printf-style functions may have hooks to set pointers to
4258 point to somewhere into the generated string. Leave them
4259 for a later excercise... */
4261 /* Fallthru to general call handling. */;
4267 /* Create constraints for the call T. */
4270 find_func_aliases_for_call (gimple t)
4272 tree fndecl = gimple_call_fndecl (t);
4273 VEC(ce_s, heap) *lhsc = NULL;
4274 VEC(ce_s, heap) *rhsc = NULL;
4277 if (fndecl != NULL_TREE
4278 && DECL_BUILT_IN (fndecl)
4279 && find_func_aliases_for_builtin_call (t))
4282 fi = get_fi_for_callee (t);
4284 || (fndecl && !fi->is_fn_info))
4286 VEC(ce_s, heap) *rhsc = NULL;
4287 int flags = gimple_call_flags (t);
4289 /* Const functions can return their arguments and addresses
4290 of global memory but not of escaped memory. */
4291 if (flags & (ECF_CONST|ECF_NOVOPS))
4293 if (gimple_call_lhs (t))
4294 handle_const_call (t, &rhsc);
4296 /* Pure functions can return addresses in and of memory
4297 reachable from their arguments, but they are not an escape
4298 point for reachable memory of their arguments. */
4299 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4300 handle_pure_call (t, &rhsc);
4302 handle_rhs_call (t, &rhsc);
4303 if (gimple_call_lhs (t))
4304 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4305 VEC_free (ce_s, heap, rhsc);
4312 /* Assign all the passed arguments to the appropriate incoming
4313 parameters of the function. */
4314 for (j = 0; j < gimple_call_num_args (t); j++)
4316 struct constraint_expr lhs ;
4317 struct constraint_expr *rhsp;
4318 tree arg = gimple_call_arg (t, j);
4320 get_constraint_for_rhs (arg, &rhsc);
4321 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4322 while (VEC_length (ce_s, rhsc) != 0)
4324 rhsp = VEC_last (ce_s, rhsc);
4325 process_constraint (new_constraint (lhs, *rhsp));
4326 VEC_pop (ce_s, rhsc);
4330 /* If we are returning a value, assign it to the result. */
4331 lhsop = gimple_call_lhs (t);
4334 struct constraint_expr rhs;
4335 struct constraint_expr *lhsp;
4337 get_constraint_for (lhsop, &lhsc);
4338 rhs = get_function_part_constraint (fi, fi_result);
4340 && DECL_RESULT (fndecl)
4341 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4343 VEC(ce_s, heap) *tem = NULL;
4344 VEC_safe_push (ce_s, heap, tem, &rhs);
4346 rhs = *VEC_index (ce_s, tem, 0);
4347 VEC_free(ce_s, heap, tem);
4349 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4350 process_constraint (new_constraint (*lhsp, rhs));
4353 /* If we pass the result decl by reference, honor that. */
4356 && DECL_RESULT (fndecl)
4357 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4359 struct constraint_expr lhs;
4360 struct constraint_expr *rhsp;
4362 get_constraint_for_address_of (lhsop, &rhsc);
4363 lhs = get_function_part_constraint (fi, fi_result);
4364 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4365 process_constraint (new_constraint (lhs, *rhsp));
4366 VEC_free (ce_s, heap, rhsc);
4369 /* If we use a static chain, pass it along. */
4370 if (gimple_call_chain (t))
4372 struct constraint_expr lhs;
4373 struct constraint_expr *rhsp;
4375 get_constraint_for (gimple_call_chain (t), &rhsc);
4376 lhs = get_function_part_constraint (fi, fi_static_chain);
4377 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4378 process_constraint (new_constraint (lhs, *rhsp));
4383 /* Walk statement T setting up aliasing constraints according to the
4384 references found in T. This function is the main part of the
4385 constraint builder. AI points to auxiliary alias information used
4386 when building alias sets and computing alias grouping heuristics. */
4389 find_func_aliases (gimple origt)
4392 VEC(ce_s, heap) *lhsc = NULL;
4393 VEC(ce_s, heap) *rhsc = NULL;
4394 struct constraint_expr *c;
4397 /* Now build constraints expressions. */
4398 if (gimple_code (t) == GIMPLE_PHI)
4403 /* For a phi node, assign all the arguments to
4405 get_constraint_for (gimple_phi_result (t), &lhsc);
4406 for (i = 0; i < gimple_phi_num_args (t); i++)
4408 tree strippedrhs = PHI_ARG_DEF (t, i);
4410 STRIP_NOPS (strippedrhs);
4411 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4413 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4415 struct constraint_expr *c2;
4416 while (VEC_length (ce_s, rhsc) > 0)
4418 c2 = VEC_last (ce_s, rhsc);
4419 process_constraint (new_constraint (*c, *c2));
4420 VEC_pop (ce_s, rhsc);
4425 /* In IPA mode, we need to generate constraints to pass call
4426 arguments through their calls. There are two cases,
4427 either a GIMPLE_CALL returning a value, or just a plain
4428 GIMPLE_CALL when we are not.
4430 In non-ipa mode, we need to generate constraints for each
4431 pointer passed by address. */
4432 else if (is_gimple_call (t))
4433 find_func_aliases_for_call (t);
4435 /* Otherwise, just a regular assignment statement. Only care about
4436 operations with pointer result, others are dealt with as escape
4437 points if they have pointer operands. */
4438 else if (is_gimple_assign (t))
4440 /* Otherwise, just a regular assignment statement. */
4441 tree lhsop = gimple_assign_lhs (t);
4442 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4444 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4445 do_structure_copy (lhsop, rhsop);
4448 enum tree_code code = gimple_assign_rhs_code (t);
4450 get_constraint_for (lhsop, &lhsc);
4452 if (code == POINTER_PLUS_EXPR)
4453 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4454 gimple_assign_rhs2 (t), &rhsc);
4455 else if (code == BIT_AND_EXPR
4456 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4458 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4459 the pointer. Handle it by offsetting it by UNKNOWN. */
4460 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4463 else if ((CONVERT_EXPR_CODE_P (code)
4464 && !(POINTER_TYPE_P (gimple_expr_type (t))
4465 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4466 || gimple_assign_single_p (t))
4467 get_constraint_for_rhs (rhsop, &rhsc);
4468 else if (truth_value_p (code))
4469 /* Truth value results are not pointer (parts). Or at least
4470 very very unreasonable obfuscation of a part. */
4474 /* All other operations are merges. */
4475 VEC (ce_s, heap) *tmp = NULL;
4476 struct constraint_expr *rhsp;
4478 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4479 for (i = 2; i < gimple_num_ops (t); ++i)
4481 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4482 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4483 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4484 VEC_truncate (ce_s, tmp, 0);
4486 VEC_free (ce_s, heap, tmp);
4488 process_all_all_constraints (lhsc, rhsc);
4490 /* If there is a store to a global variable the rhs escapes. */
4491 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4493 && is_global_var (lhsop)
4495 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4496 make_escape_constraint (rhsop);
4497 /* If this is a conversion of a non-restrict pointer to a
4498 restrict pointer track it with a new heapvar. */
4499 else if (gimple_assign_cast_p (t)
4500 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4501 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4502 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4503 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4504 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4507 /* Handle escapes through return. */
4508 else if (gimple_code (t) == GIMPLE_RETURN
4509 && gimple_return_retval (t) != NULL_TREE)
4513 || !(fi = get_vi_for_tree (cfun->decl)))
4514 make_escape_constraint (gimple_return_retval (t));
4515 else if (in_ipa_mode
4518 struct constraint_expr lhs ;
4519 struct constraint_expr *rhsp;
4522 lhs = get_function_part_constraint (fi, fi_result);
4523 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4524 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4525 process_constraint (new_constraint (lhs, *rhsp));
4528 /* Handle asms conservatively by adding escape constraints to everything. */
4529 else if (gimple_code (t) == GIMPLE_ASM)
4531 unsigned i, noutputs;
4532 const char **oconstraints;
4533 const char *constraint;
4534 bool allows_mem, allows_reg, is_inout;
4536 noutputs = gimple_asm_noutputs (t);
4537 oconstraints = XALLOCAVEC (const char *, noutputs);
4539 for (i = 0; i < noutputs; ++i)
4541 tree link = gimple_asm_output_op (t, i);
4542 tree op = TREE_VALUE (link);
4544 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4545 oconstraints[i] = constraint;
4546 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4547 &allows_reg, &is_inout);
4549 /* A memory constraint makes the address of the operand escape. */
4550 if (!allows_reg && allows_mem)
4551 make_escape_constraint (build_fold_addr_expr (op));
4553 /* The asm may read global memory, so outputs may point to
4554 any global memory. */
4557 VEC(ce_s, heap) *lhsc = NULL;
4558 struct constraint_expr rhsc, *lhsp;
4560 get_constraint_for (op, &lhsc);
4561 rhsc.var = nonlocal_id;
4564 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4565 process_constraint (new_constraint (*lhsp, rhsc));
4566 VEC_free (ce_s, heap, lhsc);
4569 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4571 tree link = gimple_asm_input_op (t, i);
4572 tree op = TREE_VALUE (link);
4574 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4576 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4577 &allows_mem, &allows_reg);
4579 /* A memory constraint makes the address of the operand escape. */
4580 if (!allows_reg && allows_mem)
4581 make_escape_constraint (build_fold_addr_expr (op));
4582 /* Strictly we'd only need the constraint to ESCAPED if
4583 the asm clobbers memory, otherwise using something
4584 along the lines of per-call clobbers/uses would be enough. */
4586 make_escape_constraint (op);
4590 VEC_free (ce_s, heap, rhsc);
4591 VEC_free (ce_s, heap, lhsc);
4595 /* Create a constraint adding to the clobber set of FI the memory
4596 pointed to by PTR. */
4599 process_ipa_clobber (varinfo_t fi, tree ptr)
4601 VEC(ce_s, heap) *ptrc = NULL;
4602 struct constraint_expr *c, lhs;
4604 get_constraint_for_rhs (ptr, &ptrc);
4605 lhs = get_function_part_constraint (fi, fi_clobbers);
4606 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4607 process_constraint (new_constraint (lhs, *c));
4608 VEC_free (ce_s, heap, ptrc);
4611 /* Walk statement T setting up clobber and use constraints according to the
4612 references found in T. This function is a main part of the
4613 IPA constraint builder. */
4616 find_func_clobbers (gimple origt)
4619 VEC(ce_s, heap) *lhsc = NULL;
4620 VEC(ce_s, heap) *rhsc = NULL;
4623 /* Add constraints for clobbered/used in IPA mode.
4624 We are not interested in what automatic variables are clobbered
4625 or used as we only use the information in the caller to which
4626 they do not escape. */
4627 gcc_assert (in_ipa_mode);
4629 /* If the stmt refers to memory in any way it better had a VUSE. */
4630 if (gimple_vuse (t) == NULL_TREE)
4633 /* We'd better have function information for the current function. */
4634 fi = lookup_vi_for_tree (cfun->decl);
4635 gcc_assert (fi != NULL);
4637 /* Account for stores in assignments and calls. */
4638 if (gimple_vdef (t) != NULL_TREE
4639 && gimple_has_lhs (t))
4641 tree lhs = gimple_get_lhs (t);
4643 while (handled_component_p (tem))
4644 tem = TREE_OPERAND (tem, 0);
4646 && !auto_var_in_fn_p (tem, cfun->decl))
4647 || INDIRECT_REF_P (tem)
4648 || (TREE_CODE (tem) == MEM_REF
4649 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4651 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4653 struct constraint_expr lhsc, *rhsp;
4655 lhsc = get_function_part_constraint (fi, fi_clobbers);
4656 get_constraint_for_address_of (lhs, &rhsc);
4657 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4658 process_constraint (new_constraint (lhsc, *rhsp));
4659 VEC_free (ce_s, heap, rhsc);
4663 /* Account for uses in assigments and returns. */
4664 if (gimple_assign_single_p (t)
4665 || (gimple_code (t) == GIMPLE_RETURN
4666 && gimple_return_retval (t) != NULL_TREE))
4668 tree rhs = (gimple_assign_single_p (t)
4669 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4671 while (handled_component_p (tem))
4672 tem = TREE_OPERAND (tem, 0);
4674 && !auto_var_in_fn_p (tem, cfun->decl))
4675 || INDIRECT_REF_P (tem)
4676 || (TREE_CODE (tem) == MEM_REF
4677 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4679 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4681 struct constraint_expr lhs, *rhsp;
4683 lhs = get_function_part_constraint (fi, fi_uses);
4684 get_constraint_for_address_of (rhs, &rhsc);
4685 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4686 process_constraint (new_constraint (lhs, *rhsp));
4687 VEC_free (ce_s, heap, rhsc);
4691 if (is_gimple_call (t))
4693 varinfo_t cfi = NULL;
4694 tree decl = gimple_call_fndecl (t);
4695 struct constraint_expr lhs, rhs;
4698 /* For builtins we do not have separate function info. For those
4699 we do not generate escapes for we have to generate clobbers/uses. */
4701 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4702 switch (DECL_FUNCTION_CODE (decl))
4704 /* The following functions use and clobber memory pointed to
4705 by their arguments. */
4706 case BUILT_IN_STRCPY:
4707 case BUILT_IN_STRNCPY:
4708 case BUILT_IN_BCOPY:
4709 case BUILT_IN_MEMCPY:
4710 case BUILT_IN_MEMMOVE:
4711 case BUILT_IN_MEMPCPY:
4712 case BUILT_IN_STPCPY:
4713 case BUILT_IN_STPNCPY:
4714 case BUILT_IN_STRCAT:
4715 case BUILT_IN_STRNCAT:
4716 case BUILT_IN_STRCPY_CHK:
4717 case BUILT_IN_STRNCPY_CHK:
4718 case BUILT_IN_MEMCPY_CHK:
4719 case BUILT_IN_MEMMOVE_CHK:
4720 case BUILT_IN_MEMPCPY_CHK:
4721 case BUILT_IN_STPCPY_CHK:
4722 case BUILT_IN_STRCAT_CHK:
4723 case BUILT_IN_STRNCAT_CHK:
4725 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4726 == BUILT_IN_BCOPY ? 1 : 0));
4727 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4728 == BUILT_IN_BCOPY ? 0 : 1));
4730 struct constraint_expr *rhsp, *lhsp;
4731 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4732 lhs = get_function_part_constraint (fi, fi_clobbers);
4733 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4734 process_constraint (new_constraint (lhs, *lhsp));
4735 VEC_free (ce_s, heap, lhsc);
4736 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4737 lhs = get_function_part_constraint (fi, fi_uses);
4738 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4739 process_constraint (new_constraint (lhs, *rhsp));
4740 VEC_free (ce_s, heap, rhsc);
4743 /* The following function clobbers memory pointed to by
4745 case BUILT_IN_MEMSET:
4746 case BUILT_IN_MEMSET_CHK:
4748 tree dest = gimple_call_arg (t, 0);
4751 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4752 lhs = get_function_part_constraint (fi, fi_clobbers);
4753 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4754 process_constraint (new_constraint (lhs, *lhsp));
4755 VEC_free (ce_s, heap, lhsc);
4758 /* The following functions clobber their second and third
4760 case BUILT_IN_SINCOS:
4761 case BUILT_IN_SINCOSF:
4762 case BUILT_IN_SINCOSL:
4764 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4765 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4768 /* The following functions clobber their second argument. */
4769 case BUILT_IN_FREXP:
4770 case BUILT_IN_FREXPF:
4771 case BUILT_IN_FREXPL:
4772 case BUILT_IN_LGAMMA_R:
4773 case BUILT_IN_LGAMMAF_R:
4774 case BUILT_IN_LGAMMAL_R:
4775 case BUILT_IN_GAMMA_R:
4776 case BUILT_IN_GAMMAF_R:
4777 case BUILT_IN_GAMMAL_R:
4779 case BUILT_IN_MODFF:
4780 case BUILT_IN_MODFL:
4782 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4785 /* The following functions clobber their third argument. */
4786 case BUILT_IN_REMQUO:
4787 case BUILT_IN_REMQUOF:
4788 case BUILT_IN_REMQUOL:
4790 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4793 /* The following functions neither read nor clobber memory. */
4794 case BUILT_IN_ASSUME_ALIGNED:
4797 /* Trampolines are of no interest to us. */
4798 case BUILT_IN_INIT_TRAMPOLINE:
4799 case BUILT_IN_ADJUST_TRAMPOLINE:
4801 case BUILT_IN_VA_START:
4802 case BUILT_IN_VA_END:
4804 /* printf-style functions may have hooks to set pointers to
4805 point to somewhere into the generated string. Leave them
4806 for a later excercise... */
4808 /* Fallthru to general call handling. */;
4811 /* Parameters passed by value are used. */
4812 lhs = get_function_part_constraint (fi, fi_uses);
4813 for (i = 0; i < gimple_call_num_args (t); i++)
4815 struct constraint_expr *rhsp;
4816 tree arg = gimple_call_arg (t, i);
4818 if (TREE_CODE (arg) == SSA_NAME
4819 || is_gimple_min_invariant (arg))
4822 get_constraint_for_address_of (arg, &rhsc);
4823 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4824 process_constraint (new_constraint (lhs, *rhsp));
4825 VEC_free (ce_s, heap, rhsc);
4828 /* Build constraints for propagating clobbers/uses along the
4830 cfi = get_fi_for_callee (t);
4831 if (cfi->id == anything_id)
4833 if (gimple_vdef (t))
4834 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4836 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4841 /* For callees without function info (that's external functions),
4842 ESCAPED is clobbered and used. */
4843 if (gimple_call_fndecl (t)
4844 && !cfi->is_fn_info)
4848 if (gimple_vdef (t))
4849 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4851 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4853 /* Also honor the call statement use/clobber info. */
4854 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4855 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4857 if ((vi = lookup_call_use_vi (t)) != NULL)
4858 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4863 /* Otherwise the caller clobbers and uses what the callee does.
4864 ??? This should use a new complex constraint that filters
4865 local variables of the callee. */
4866 if (gimple_vdef (t))
4868 lhs = get_function_part_constraint (fi, fi_clobbers);
4869 rhs = get_function_part_constraint (cfi, fi_clobbers);
4870 process_constraint (new_constraint (lhs, rhs));
4872 lhs = get_function_part_constraint (fi, fi_uses);
4873 rhs = get_function_part_constraint (cfi, fi_uses);
4874 process_constraint (new_constraint (lhs, rhs));
4876 else if (gimple_code (t) == GIMPLE_ASM)
4878 /* ??? Ick. We can do better. */
4879 if (gimple_vdef (t))
4880 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4882 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4886 VEC_free (ce_s, heap, rhsc);
4890 /* Find the first varinfo in the same variable as START that overlaps with
4891 OFFSET. Return NULL if we can't find one. */
4894 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4896 /* If the offset is outside of the variable, bail out. */
4897 if (offset >= start->fullsize)
4900 /* If we cannot reach offset from start, lookup the first field
4901 and start from there. */
4902 if (start->offset > offset)
4903 start = lookup_vi_for_tree (start->decl);
4907 /* We may not find a variable in the field list with the actual
4908 offset when when we have glommed a structure to a variable.
4909 In that case, however, offset should still be within the size
4911 if (offset >= start->offset
4912 && (offset - start->offset) < start->size)
4921 /* Find the first varinfo in the same variable as START that overlaps with
4922 OFFSET. If there is no such varinfo the varinfo directly preceding
4923 OFFSET is returned. */
4926 first_or_preceding_vi_for_offset (varinfo_t start,
4927 unsigned HOST_WIDE_INT offset)
4929 /* If we cannot reach offset from start, lookup the first field
4930 and start from there. */
4931 if (start->offset > offset)
4932 start = lookup_vi_for_tree (start->decl);
4934 /* We may not find a variable in the field list with the actual
4935 offset when when we have glommed a structure to a variable.
4936 In that case, however, offset should still be within the size
4938 If we got beyond the offset we look for return the field
4939 directly preceding offset which may be the last field. */
4941 && offset >= start->offset
4942 && !((offset - start->offset) < start->size))
4943 start = start->next;
4949 /* This structure is used during pushing fields onto the fieldstack
4950 to track the offset of the field, since bitpos_of_field gives it
4951 relative to its immediate containing type, and we want it relative
4952 to the ultimate containing object. */
4956 /* Offset from the base of the base containing object to this field. */
4957 HOST_WIDE_INT offset;
4959 /* Size, in bits, of the field. */
4960 unsigned HOST_WIDE_INT size;
4962 unsigned has_unknown_size : 1;
4964 unsigned must_have_pointers : 1;
4966 unsigned may_have_pointers : 1;
4968 unsigned only_restrict_pointers : 1;
4970 typedef struct fieldoff fieldoff_s;
4972 DEF_VEC_O(fieldoff_s);
4973 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4975 /* qsort comparison function for two fieldoff's PA and PB */
4978 fieldoff_compare (const void *pa, const void *pb)
4980 const fieldoff_s *foa = (const fieldoff_s *)pa;
4981 const fieldoff_s *fob = (const fieldoff_s *)pb;
4982 unsigned HOST_WIDE_INT foasize, fobsize;
4984 if (foa->offset < fob->offset)
4986 else if (foa->offset > fob->offset)
4989 foasize = foa->size;
4990 fobsize = fob->size;
4991 if (foasize < fobsize)
4993 else if (foasize > fobsize)
4998 /* Sort a fieldstack according to the field offset and sizes. */
5000 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
5002 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
5005 /* Return true if V is a tree that we can have subvars for.
5006 Normally, this is any aggregate type. Also complex
5007 types which are not gimple registers can have subvars. */
5010 var_can_have_subvars (const_tree v)
5012 /* Volatile variables should never have subvars. */
5013 if (TREE_THIS_VOLATILE (v))
5016 /* Non decls or memory tags can never have subvars. */
5020 /* Aggregates without overlapping fields can have subvars. */
5021 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
5027 /* Return true if T is a type that does contain pointers. */
5030 type_must_have_pointers (tree type)
5032 if (POINTER_TYPE_P (type))
5035 if (TREE_CODE (type) == ARRAY_TYPE)
5036 return type_must_have_pointers (TREE_TYPE (type));
5038 /* A function or method can have pointers as arguments, so track
5039 those separately. */
5040 if (TREE_CODE (type) == FUNCTION_TYPE
5041 || TREE_CODE (type) == METHOD_TYPE)
5048 field_must_have_pointers (tree t)
5050 return type_must_have_pointers (TREE_TYPE (t));
5053 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5054 the fields of TYPE onto fieldstack, recording their offsets along
5057 OFFSET is used to keep track of the offset in this entire
5058 structure, rather than just the immediately containing structure.
5059 Returns false if the caller is supposed to handle the field we
5063 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5064 HOST_WIDE_INT offset)
5067 bool empty_p = true;
5069 if (TREE_CODE (type) != RECORD_TYPE)
5072 /* If the vector of fields is growing too big, bail out early.
5073 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5075 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5078 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5079 if (TREE_CODE (field) == FIELD_DECL)
5082 HOST_WIDE_INT foff = bitpos_of_field (field);
5084 if (!var_can_have_subvars (field)
5085 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5086 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5088 else if (!push_fields_onto_fieldstack
5089 (TREE_TYPE (field), fieldstack, offset + foff)
5090 && (DECL_SIZE (field)
5091 && !integer_zerop (DECL_SIZE (field))))
5092 /* Empty structures may have actual size, like in C++. So
5093 see if we didn't push any subfields and the size is
5094 nonzero, push the field onto the stack. */
5099 fieldoff_s *pair = NULL;
5100 bool has_unknown_size = false;
5101 bool must_have_pointers_p;
5103 if (!VEC_empty (fieldoff_s, *fieldstack))
5104 pair = VEC_last (fieldoff_s, *fieldstack);
5106 /* If there isn't anything at offset zero, create sth. */
5108 && offset + foff != 0)
5110 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5112 pair->size = offset + foff;
5113 pair->has_unknown_size = false;
5114 pair->must_have_pointers = false;
5115 pair->may_have_pointers = false;
5116 pair->only_restrict_pointers = false;
5119 if (!DECL_SIZE (field)
5120 || !host_integerp (DECL_SIZE (field), 1))
5121 has_unknown_size = true;
5123 /* If adjacent fields do not contain pointers merge them. */
5124 must_have_pointers_p = field_must_have_pointers (field);
5126 && !has_unknown_size
5127 && !must_have_pointers_p
5128 && !pair->must_have_pointers
5129 && !pair->has_unknown_size
5130 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5132 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5136 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5137 pair->offset = offset + foff;
5138 pair->has_unknown_size = has_unknown_size;
5139 if (!has_unknown_size)
5140 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5143 pair->must_have_pointers = must_have_pointers_p;
5144 pair->may_have_pointers = true;
5145 pair->only_restrict_pointers
5146 = (!has_unknown_size
5147 && POINTER_TYPE_P (TREE_TYPE (field))
5148 && TYPE_RESTRICT (TREE_TYPE (field)));
5158 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5159 if it is a varargs function. */
5162 count_num_arguments (tree decl, bool *is_varargs)
5164 unsigned int num = 0;
5167 /* Capture named arguments for K&R functions. They do not
5168 have a prototype and thus no TYPE_ARG_TYPES. */
5169 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5172 /* Check if the function has variadic arguments. */
5173 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5174 if (TREE_VALUE (t) == void_type_node)
5182 /* Creation function node for DECL, using NAME, and return the index
5183 of the variable we've created for the function. */
5186 create_function_info_for (tree decl, const char *name)
5188 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5189 varinfo_t vi, prev_vi;
5192 bool is_varargs = false;
5193 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5195 /* Create the variable info. */
5197 vi = new_var_info (decl, name);
5200 vi->fullsize = fi_parm_base + num_args;
5202 vi->may_have_pointers = false;
5205 insert_vi_for_tree (vi->decl, vi);
5209 /* Create a variable for things the function clobbers and one for
5210 things the function uses. */
5212 varinfo_t clobbervi, usevi;
5213 const char *newname;
5216 asprintf (&tempname, "%s.clobber", name);
5217 newname = ggc_strdup (tempname);
5220 clobbervi = new_var_info (NULL, newname);
5221 clobbervi->offset = fi_clobbers;
5222 clobbervi->size = 1;
5223 clobbervi->fullsize = vi->fullsize;
5224 clobbervi->is_full_var = true;
5225 clobbervi->is_global_var = false;
5226 gcc_assert (prev_vi->offset < clobbervi->offset);
5227 prev_vi->next = clobbervi;
5228 prev_vi = clobbervi;
5230 asprintf (&tempname, "%s.use", name);
5231 newname = ggc_strdup (tempname);
5234 usevi = new_var_info (NULL, newname);
5235 usevi->offset = fi_uses;
5237 usevi->fullsize = vi->fullsize;
5238 usevi->is_full_var = true;
5239 usevi->is_global_var = false;
5240 gcc_assert (prev_vi->offset < usevi->offset);
5241 prev_vi->next = usevi;
5245 /* And one for the static chain. */
5246 if (fn->static_chain_decl != NULL_TREE)
5249 const char *newname;
5252 asprintf (&tempname, "%s.chain", name);
5253 newname = ggc_strdup (tempname);
5256 chainvi = new_var_info (fn->static_chain_decl, newname);
5257 chainvi->offset = fi_static_chain;
5259 chainvi->fullsize = vi->fullsize;
5260 chainvi->is_full_var = true;
5261 chainvi->is_global_var = false;
5262 gcc_assert (prev_vi->offset < chainvi->offset);
5263 prev_vi->next = chainvi;
5265 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5268 /* Create a variable for the return var. */
5269 if (DECL_RESULT (decl) != NULL
5270 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5273 const char *newname;
5275 tree resultdecl = decl;
5277 if (DECL_RESULT (decl))
5278 resultdecl = DECL_RESULT (decl);
5280 asprintf (&tempname, "%s.result", name);
5281 newname = ggc_strdup (tempname);
5284 resultvi = new_var_info (resultdecl, newname);
5285 resultvi->offset = fi_result;
5287 resultvi->fullsize = vi->fullsize;
5288 resultvi->is_full_var = true;
5289 if (DECL_RESULT (decl))
5290 resultvi->may_have_pointers = true;
5291 gcc_assert (prev_vi->offset < resultvi->offset);
5292 prev_vi->next = resultvi;
5294 if (DECL_RESULT (decl))
5295 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5298 /* Set up variables for each argument. */
5299 arg = DECL_ARGUMENTS (decl);
5300 for (i = 0; i < num_args; i++)
5303 const char *newname;
5305 tree argdecl = decl;
5310 asprintf (&tempname, "%s.arg%d", name, i);
5311 newname = ggc_strdup (tempname);
5314 argvi = new_var_info (argdecl, newname);
5315 argvi->offset = fi_parm_base + i;
5317 argvi->is_full_var = true;
5318 argvi->fullsize = vi->fullsize;
5320 argvi->may_have_pointers = true;
5321 gcc_assert (prev_vi->offset < argvi->offset);
5322 prev_vi->next = argvi;
5326 insert_vi_for_tree (arg, argvi);
5327 arg = DECL_CHAIN (arg);
5331 /* Add one representative for all further args. */
5335 const char *newname;
5339 asprintf (&tempname, "%s.varargs", name);
5340 newname = ggc_strdup (tempname);
5343 /* We need sth that can be pointed to for va_start. */
5344 decl = build_fake_var_decl (ptr_type_node);
5346 argvi = new_var_info (decl, newname);
5347 argvi->offset = fi_parm_base + num_args;
5349 argvi->is_full_var = true;
5350 argvi->is_heap_var = true;
5351 argvi->fullsize = vi->fullsize;
5352 gcc_assert (prev_vi->offset < argvi->offset);
5353 prev_vi->next = argvi;
5361 /* Return true if FIELDSTACK contains fields that overlap.
5362 FIELDSTACK is assumed to be sorted by offset. */
5365 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5367 fieldoff_s *fo = NULL;
5369 HOST_WIDE_INT lastoffset = -1;
5371 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5373 if (fo->offset == lastoffset)
5375 lastoffset = fo->offset;
5380 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5381 This will also create any varinfo structures necessary for fields
5385 create_variable_info_for_1 (tree decl, const char *name)
5387 varinfo_t vi, newvi;
5388 tree decl_type = TREE_TYPE (decl);
5389 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5390 VEC (fieldoff_s,heap) *fieldstack = NULL;
5395 || !host_integerp (declsize, 1))
5397 vi = new_var_info (decl, name);
5401 vi->is_unknown_size_var = true;
5402 vi->is_full_var = true;
5403 vi->may_have_pointers = true;
5407 /* Collect field information. */
5408 if (use_field_sensitive
5409 && var_can_have_subvars (decl)
5410 /* ??? Force us to not use subfields for global initializers
5411 in IPA mode. Else we'd have to parse arbitrary initializers. */
5413 && is_global_var (decl)
5414 && DECL_INITIAL (decl)))
5416 fieldoff_s *fo = NULL;
5417 bool notokay = false;
5420 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5422 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5423 if (fo->has_unknown_size
5430 /* We can't sort them if we have a field with a variable sized type,
5431 which will make notokay = true. In that case, we are going to return
5432 without creating varinfos for the fields anyway, so sorting them is a
5436 sort_fieldstack (fieldstack);
5437 /* Due to some C++ FE issues, like PR 22488, we might end up
5438 what appear to be overlapping fields even though they,
5439 in reality, do not overlap. Until the C++ FE is fixed,
5440 we will simply disable field-sensitivity for these cases. */
5441 notokay = check_for_overlaps (fieldstack);
5445 VEC_free (fieldoff_s, heap, fieldstack);
5448 /* If we didn't end up collecting sub-variables create a full
5449 variable for the decl. */
5450 if (VEC_length (fieldoff_s, fieldstack) <= 1
5451 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5453 vi = new_var_info (decl, name);
5455 vi->may_have_pointers = true;
5456 vi->fullsize = TREE_INT_CST_LOW (declsize);
5457 vi->size = vi->fullsize;
5458 vi->is_full_var = true;
5459 VEC_free (fieldoff_s, heap, fieldstack);
5463 vi = new_var_info (decl, name);
5464 vi->fullsize = TREE_INT_CST_LOW (declsize);
5465 for (i = 0, newvi = vi;
5466 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5467 ++i, newvi = newvi->next)
5469 const char *newname = "NULL";
5474 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5475 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5476 newname = ggc_strdup (tempname);
5479 newvi->name = newname;
5480 newvi->offset = fo->offset;
5481 newvi->size = fo->size;
5482 newvi->fullsize = vi->fullsize;
5483 newvi->may_have_pointers = fo->may_have_pointers;
5484 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5485 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5486 newvi->next = new_var_info (decl, name);
5489 VEC_free (fieldoff_s, heap, fieldstack);
5495 create_variable_info_for (tree decl, const char *name)
5497 varinfo_t vi = create_variable_info_for_1 (decl, name);
5498 unsigned int id = vi->id;
5500 insert_vi_for_tree (decl, vi);
5502 if (TREE_CODE (decl) != VAR_DECL)
5505 /* Create initial constraints for globals. */
5506 for (; vi; vi = vi->next)
5508 if (!vi->may_have_pointers
5509 || !vi->is_global_var)
5512 /* Mark global restrict qualified pointers. */
5513 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5514 && TYPE_RESTRICT (TREE_TYPE (decl)))
5515 || vi->only_restrict_pointers)
5516 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5518 /* In non-IPA mode the initializer from nonlocal is all we need. */
5520 || DECL_HARD_REGISTER (decl))
5521 make_copy_constraint (vi, nonlocal_id);
5525 struct varpool_node *vnode = varpool_get_node (decl);
5527 /* For escaped variables initialize them from nonlocal. */
5528 if (!varpool_all_refs_explicit_p (vnode))
5529 make_copy_constraint (vi, nonlocal_id);
5531 /* If this is a global variable with an initializer and we are in
5532 IPA mode generate constraints for it. */
5533 if (DECL_INITIAL (decl))
5535 VEC (ce_s, heap) *rhsc = NULL;
5536 struct constraint_expr lhs, *rhsp;
5538 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5542 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5543 process_constraint (new_constraint (lhs, *rhsp));
5544 /* If this is a variable that escapes from the unit
5545 the initializer escapes as well. */
5546 if (!varpool_all_refs_explicit_p (vnode))
5548 lhs.var = escaped_id;
5551 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5552 process_constraint (new_constraint (lhs, *rhsp));
5554 VEC_free (ce_s, heap, rhsc);
5562 /* Print out the points-to solution for VAR to FILE. */
5565 dump_solution_for_var (FILE *file, unsigned int var)
5567 varinfo_t vi = get_varinfo (var);
5571 /* Dump the solution for unified vars anyway, this avoids difficulties
5572 in scanning dumps in the testsuite. */
5573 fprintf (file, "%s = { ", vi->name);
5574 vi = get_varinfo (find (var));
5575 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5576 fprintf (file, "%s ", get_varinfo (i)->name);
5577 fprintf (file, "}");
5579 /* But note when the variable was unified. */
5581 fprintf (file, " same as %s", vi->name);
5583 fprintf (file, "\n");
5586 /* Print the points-to solution for VAR to stdout. */
5589 debug_solution_for_var (unsigned int var)
5591 dump_solution_for_var (stdout, var);
5594 /* Create varinfo structures for all of the variables in the
5595 function for intraprocedural mode. */
5598 intra_create_variable_infos (void)
5602 /* For each incoming pointer argument arg, create the constraint ARG
5603 = NONLOCAL or a dummy variable if it is a restrict qualified
5604 passed-by-reference argument. */
5605 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5609 /* For restrict qualified pointers to objects passed by
5610 reference build a real representative for the pointed-to object.
5611 Treat restrict qualified references the same. */
5612 if (TYPE_RESTRICT (TREE_TYPE (t))
5613 && ((DECL_BY_REFERENCE (t) && POINTER_TYPE_P (TREE_TYPE (t)))
5614 || TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE))
5616 struct constraint_expr lhsc, rhsc;
5618 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t)));
5619 DECL_EXTERNAL (heapvar) = 1;
5620 vi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS");
5621 insert_vi_for_tree (heapvar, vi);
5622 lhsc.var = get_vi_for_tree (t)->id;
5626 rhsc.type = ADDRESSOF;
5628 process_constraint (new_constraint (lhsc, rhsc));
5629 vi->is_restrict_var = 1;
5630 for (; vi; vi = vi->next)
5631 if (vi->may_have_pointers)
5633 if (vi->only_restrict_pointers)
5634 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5635 make_copy_constraint (vi, nonlocal_id);
5640 for (p = get_vi_for_tree (t); p; p = p->next)
5642 if (p->may_have_pointers)
5643 make_constraint_from (p, nonlocal_id);
5644 if (p->only_restrict_pointers)
5645 make_constraint_from_restrict (p, "PARM_RESTRICT");
5647 if (POINTER_TYPE_P (TREE_TYPE (t))
5648 && TYPE_RESTRICT (TREE_TYPE (t)))
5649 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5652 /* Add a constraint for a result decl that is passed by reference. */
5653 if (DECL_RESULT (cfun->decl)
5654 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5656 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5658 for (p = result_vi; p; p = p->next)
5659 make_constraint_from (p, nonlocal_id);
5662 /* Add a constraint for the incoming static chain parameter. */
5663 if (cfun->static_chain_decl != NULL_TREE)
5665 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5667 for (p = chain_vi; p; p = p->next)
5668 make_constraint_from (p, nonlocal_id);
5672 /* Structure used to put solution bitmaps in a hashtable so they can
5673 be shared among variables with the same points-to set. */
5675 typedef struct shared_bitmap_info
5679 } *shared_bitmap_info_t;
5680 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5682 static htab_t shared_bitmap_table;
5684 /* Hash function for a shared_bitmap_info_t */
5687 shared_bitmap_hash (const void *p)
5689 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5690 return bi->hashcode;
5693 /* Equality function for two shared_bitmap_info_t's. */
5696 shared_bitmap_eq (const void *p1, const void *p2)
5698 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5699 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5700 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5703 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5704 existing instance if there is one, NULL otherwise. */
5707 shared_bitmap_lookup (bitmap pt_vars)
5710 struct shared_bitmap_info sbi;
5712 sbi.pt_vars = pt_vars;
5713 sbi.hashcode = bitmap_hash (pt_vars);
5715 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5716 sbi.hashcode, NO_INSERT);
5720 return ((shared_bitmap_info_t) *slot)->pt_vars;
5724 /* Add a bitmap to the shared bitmap hashtable. */
5727 shared_bitmap_add (bitmap pt_vars)
5730 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5732 sbi->pt_vars = pt_vars;
5733 sbi->hashcode = bitmap_hash (pt_vars);
5735 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5736 sbi->hashcode, INSERT);
5737 gcc_assert (!*slot);
5738 *slot = (void *) sbi;
5742 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5745 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5750 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5752 varinfo_t vi = get_varinfo (i);
5754 /* The only artificial variables that are allowed in a may-alias
5755 set are heap variables. */
5756 if (vi->is_artificial_var && !vi->is_heap_var)
5759 if (TREE_CODE (vi->decl) == VAR_DECL
5760 || TREE_CODE (vi->decl) == PARM_DECL
5761 || TREE_CODE (vi->decl) == RESULT_DECL)
5763 /* If we are in IPA mode we will not recompute points-to
5764 sets after inlining so make sure they stay valid. */
5766 && !DECL_PT_UID_SET_P (vi->decl))
5767 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5769 /* Add the decl to the points-to set. Note that the points-to
5770 set contains global variables. */
5771 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5772 if (vi->is_global_var)
5773 pt->vars_contains_global = true;
5779 /* Compute the points-to solution *PT for the variable VI. */
5782 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5786 bitmap finished_solution;
5790 memset (pt, 0, sizeof (struct pt_solution));
5792 /* This variable may have been collapsed, let's get the real
5794 vi = get_varinfo (find (orig_vi->id));
5796 /* Translate artificial variables into SSA_NAME_PTR_INFO
5798 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5800 varinfo_t vi = get_varinfo (i);
5802 if (vi->is_artificial_var)
5804 if (vi->id == nothing_id)
5806 else if (vi->id == escaped_id)
5809 pt->ipa_escaped = 1;
5813 else if (vi->id == nonlocal_id)
5815 else if (vi->is_heap_var)
5816 /* We represent heapvars in the points-to set properly. */
5818 else if (vi->id == readonly_id)
5821 else if (vi->id == anything_id
5822 || vi->id == integer_id)
5825 if (vi->is_restrict_var)
5826 pt->vars_contains_restrict = true;
5829 /* Instead of doing extra work, simply do not create
5830 elaborate points-to information for pt_anything pointers. */
5832 && (orig_vi->is_artificial_var
5833 || !pt->vars_contains_restrict))
5836 /* Share the final set of variables when possible. */
5837 finished_solution = BITMAP_GGC_ALLOC ();
5838 stats.points_to_sets_created++;
5840 set_uids_in_ptset (finished_solution, vi->solution, pt);
5841 result = shared_bitmap_lookup (finished_solution);
5844 shared_bitmap_add (finished_solution);
5845 pt->vars = finished_solution;
5850 bitmap_clear (finished_solution);
5854 /* Given a pointer variable P, fill in its points-to set. */
5857 find_what_p_points_to (tree p)
5859 struct ptr_info_def *pi;
5863 /* For parameters, get at the points-to set for the actual parm
5865 if (TREE_CODE (p) == SSA_NAME
5866 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5867 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5868 && SSA_NAME_IS_DEFAULT_DEF (p))
5869 lookup_p = SSA_NAME_VAR (p);
5871 vi = lookup_vi_for_tree (lookup_p);
5875 pi = get_ptr_info (p);
5876 find_what_var_points_to (vi, &pi->pt);
5880 /* Query statistics for points-to solutions. */
5883 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5884 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5885 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5886 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5890 dump_pta_stats (FILE *s)
5892 fprintf (s, "\nPTA query stats:\n");
5893 fprintf (s, " pt_solution_includes: "
5894 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5895 HOST_WIDE_INT_PRINT_DEC" queries\n",
5896 pta_stats.pt_solution_includes_no_alias,
5897 pta_stats.pt_solution_includes_no_alias
5898 + pta_stats.pt_solution_includes_may_alias);
5899 fprintf (s, " pt_solutions_intersect: "
5900 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5901 HOST_WIDE_INT_PRINT_DEC" queries\n",
5902 pta_stats.pt_solutions_intersect_no_alias,
5903 pta_stats.pt_solutions_intersect_no_alias
5904 + pta_stats.pt_solutions_intersect_may_alias);
5908 /* Reset the points-to solution *PT to a conservative default
5909 (point to anything). */
5912 pt_solution_reset (struct pt_solution *pt)
5914 memset (pt, 0, sizeof (struct pt_solution));
5915 pt->anything = true;
5918 /* Set the points-to solution *PT to point only to the variables
5919 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5920 global variables and VARS_CONTAINS_RESTRICT specifies whether
5921 it contains restrict tag variables. */
5924 pt_solution_set (struct pt_solution *pt, bitmap vars,
5925 bool vars_contains_global, bool vars_contains_restrict)
5927 memset (pt, 0, sizeof (struct pt_solution));
5929 pt->vars_contains_global = vars_contains_global;
5930 pt->vars_contains_restrict = vars_contains_restrict;
5933 /* Set the points-to solution *PT to point only to the variable VAR. */
5936 pt_solution_set_var (struct pt_solution *pt, tree var)
5938 memset (pt, 0, sizeof (struct pt_solution));
5939 pt->vars = BITMAP_GGC_ALLOC ();
5940 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5941 pt->vars_contains_global = is_global_var (var);
5944 /* Computes the union of the points-to solutions *DEST and *SRC and
5945 stores the result in *DEST. This changes the points-to bitmap
5946 of *DEST and thus may not be used if that might be shared.
5947 The points-to bitmap of *SRC and *DEST will not be shared after
5948 this function if they were not before. */
5951 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5953 dest->anything |= src->anything;
5956 pt_solution_reset (dest);
5960 dest->nonlocal |= src->nonlocal;
5961 dest->escaped |= src->escaped;
5962 dest->ipa_escaped |= src->ipa_escaped;
5963 dest->null |= src->null;
5964 dest->vars_contains_global |= src->vars_contains_global;
5965 dest->vars_contains_restrict |= src->vars_contains_restrict;
5970 dest->vars = BITMAP_GGC_ALLOC ();
5971 bitmap_ior_into (dest->vars, src->vars);
5974 /* Return true if the points-to solution *PT is empty. */
5977 pt_solution_empty_p (struct pt_solution *pt)
5984 && !bitmap_empty_p (pt->vars))
5987 /* If the solution includes ESCAPED, check if that is empty. */
5989 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5992 /* If the solution includes ESCAPED, check if that is empty. */
5994 && !pt_solution_empty_p (&ipa_escaped_pt))
6000 /* Return true if the points-to solution *PT only point to a single var, and
6001 return the var uid in *UID. */
6004 pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid)
6006 if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped
6007 || pt->null || pt->vars == NULL
6008 || !bitmap_single_bit_set_p (pt->vars))
6011 *uid = bitmap_first_set_bit (pt->vars);
6015 /* Return true if the points-to solution *PT includes global memory. */
6018 pt_solution_includes_global (struct pt_solution *pt)
6022 || pt->vars_contains_global)
6026 return pt_solution_includes_global (&cfun->gimple_df->escaped);
6028 if (pt->ipa_escaped)
6029 return pt_solution_includes_global (&ipa_escaped_pt);
6031 /* ??? This predicate is not correct for the IPA-PTA solution
6032 as we do not properly distinguish between unit escape points
6033 and global variables. */
6034 if (cfun->gimple_df->ipa_pta)
6040 /* Return true if the points-to solution *PT includes the variable
6041 declaration DECL. */
6044 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
6050 && is_global_var (decl))
6054 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
6057 /* If the solution includes ESCAPED, check it. */
6059 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
6062 /* If the solution includes ESCAPED, check it. */
6064 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6071 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6073 bool res = pt_solution_includes_1 (pt, decl);
6075 ++pta_stats.pt_solution_includes_may_alias;
6077 ++pta_stats.pt_solution_includes_no_alias;
6081 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6085 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6087 if (pt1->anything || pt2->anything)
6090 /* If either points to unknown global memory and the other points to
6091 any global memory they alias. */
6094 || pt2->vars_contains_global))
6096 && pt1->vars_contains_global))
6099 /* Check the escaped solution if required. */
6100 if ((pt1->escaped || pt2->escaped)
6101 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6103 /* If both point to escaped memory and that solution
6104 is not empty they alias. */
6105 if (pt1->escaped && pt2->escaped)
6108 /* If either points to escaped memory see if the escaped solution
6109 intersects with the other. */
6111 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6113 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6117 /* Check the escaped solution if required.
6118 ??? Do we need to check the local against the IPA escaped sets? */
6119 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6120 && !pt_solution_empty_p (&ipa_escaped_pt))
6122 /* If both point to escaped memory and that solution
6123 is not empty they alias. */
6124 if (pt1->ipa_escaped && pt2->ipa_escaped)
6127 /* If either points to escaped memory see if the escaped solution
6128 intersects with the other. */
6129 if ((pt1->ipa_escaped
6130 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6131 || (pt2->ipa_escaped
6132 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6136 /* Now both pointers alias if their points-to solution intersects. */
6139 && bitmap_intersect_p (pt1->vars, pt2->vars));
6143 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6145 bool res = pt_solutions_intersect_1 (pt1, pt2);
6147 ++pta_stats.pt_solutions_intersect_may_alias;
6149 ++pta_stats.pt_solutions_intersect_no_alias;
6153 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6154 qualified pointers are possibly based on the same pointer. */
6157 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6158 struct pt_solution *pt2)
6160 /* If we deal with points-to solutions of two restrict qualified
6161 pointers solely rely on the pointed-to variable bitmap intersection.
6162 For two pointers that are based on each other the bitmaps will
6164 if (pt1->vars_contains_restrict
6165 && pt2->vars_contains_restrict)
6167 gcc_assert (pt1->vars && pt2->vars);
6168 return bitmap_intersect_p (pt1->vars, pt2->vars);
6175 /* Dump points-to information to OUTFILE. */
6178 dump_sa_points_to_info (FILE *outfile)
6182 fprintf (outfile, "\nPoints-to sets\n\n");
6184 if (dump_flags & TDF_STATS)
6186 fprintf (outfile, "Stats:\n");
6187 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6188 fprintf (outfile, "Non-pointer vars: %d\n",
6189 stats.nonpointer_vars);
6190 fprintf (outfile, "Statically unified vars: %d\n",
6191 stats.unified_vars_static);
6192 fprintf (outfile, "Dynamically unified vars: %d\n",
6193 stats.unified_vars_dynamic);
6194 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6195 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6196 fprintf (outfile, "Number of implicit edges: %d\n",
6197 stats.num_implicit_edges);
6200 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6202 varinfo_t vi = get_varinfo (i);
6203 if (!vi->may_have_pointers)
6205 dump_solution_for_var (outfile, i);
6210 /* Debug points-to information to stderr. */
6213 debug_sa_points_to_info (void)
6215 dump_sa_points_to_info (stderr);
6219 /* Initialize the always-existing constraint variables for NULL
6220 ANYTHING, READONLY, and INTEGER */
6223 init_base_vars (void)
6225 struct constraint_expr lhs, rhs;
6226 varinfo_t var_anything;
6227 varinfo_t var_nothing;
6228 varinfo_t var_readonly;
6229 varinfo_t var_escaped;
6230 varinfo_t var_nonlocal;
6231 varinfo_t var_storedanything;
6232 varinfo_t var_integer;
6234 /* Create the NULL variable, used to represent that a variable points
6236 var_nothing = new_var_info (NULL_TREE, "NULL");
6237 gcc_assert (var_nothing->id == nothing_id);
6238 var_nothing->is_artificial_var = 1;
6239 var_nothing->offset = 0;
6240 var_nothing->size = ~0;
6241 var_nothing->fullsize = ~0;
6242 var_nothing->is_special_var = 1;
6243 var_nothing->may_have_pointers = 0;
6244 var_nothing->is_global_var = 0;
6246 /* Create the ANYTHING variable, used to represent that a variable
6247 points to some unknown piece of memory. */
6248 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6249 gcc_assert (var_anything->id == anything_id);
6250 var_anything->is_artificial_var = 1;
6251 var_anything->size = ~0;
6252 var_anything->offset = 0;
6253 var_anything->next = NULL;
6254 var_anything->fullsize = ~0;
6255 var_anything->is_special_var = 1;
6257 /* Anything points to anything. This makes deref constraints just
6258 work in the presence of linked list and other p = *p type loops,
6259 by saying that *ANYTHING = ANYTHING. */
6261 lhs.var = anything_id;
6263 rhs.type = ADDRESSOF;
6264 rhs.var = anything_id;
6267 /* This specifically does not use process_constraint because
6268 process_constraint ignores all anything = anything constraints, since all
6269 but this one are redundant. */
6270 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6272 /* Create the READONLY variable, used to represent that a variable
6273 points to readonly memory. */
6274 var_readonly = new_var_info (NULL_TREE, "READONLY");
6275 gcc_assert (var_readonly->id == readonly_id);
6276 var_readonly->is_artificial_var = 1;
6277 var_readonly->offset = 0;
6278 var_readonly->size = ~0;
6279 var_readonly->fullsize = ~0;
6280 var_readonly->next = NULL;
6281 var_readonly->is_special_var = 1;
6283 /* readonly memory points to anything, in order to make deref
6284 easier. In reality, it points to anything the particular
6285 readonly variable can point to, but we don't track this
6288 lhs.var = readonly_id;
6290 rhs.type = ADDRESSOF;
6291 rhs.var = readonly_id; /* FIXME */
6293 process_constraint (new_constraint (lhs, rhs));
6295 /* Create the ESCAPED variable, used to represent the set of escaped
6297 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6298 gcc_assert (var_escaped->id == escaped_id);
6299 var_escaped->is_artificial_var = 1;
6300 var_escaped->offset = 0;
6301 var_escaped->size = ~0;
6302 var_escaped->fullsize = ~0;
6303 var_escaped->is_special_var = 0;
6305 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6307 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6308 gcc_assert (var_nonlocal->id == nonlocal_id);
6309 var_nonlocal->is_artificial_var = 1;
6310 var_nonlocal->offset = 0;
6311 var_nonlocal->size = ~0;
6312 var_nonlocal->fullsize = ~0;
6313 var_nonlocal->is_special_var = 1;
6315 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6317 lhs.var = escaped_id;
6320 rhs.var = escaped_id;
6322 process_constraint (new_constraint (lhs, rhs));
6324 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6325 whole variable escapes. */
6327 lhs.var = escaped_id;
6330 rhs.var = escaped_id;
6331 rhs.offset = UNKNOWN_OFFSET;
6332 process_constraint (new_constraint (lhs, rhs));
6334 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6335 everything pointed to by escaped points to what global memory can
6338 lhs.var = escaped_id;
6341 rhs.var = nonlocal_id;
6343 process_constraint (new_constraint (lhs, rhs));
6345 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6346 global memory may point to global memory and escaped memory. */
6348 lhs.var = nonlocal_id;
6350 rhs.type = ADDRESSOF;
6351 rhs.var = nonlocal_id;
6353 process_constraint (new_constraint (lhs, rhs));
6354 rhs.type = ADDRESSOF;
6355 rhs.var = escaped_id;
6357 process_constraint (new_constraint (lhs, rhs));
6359 /* Create the STOREDANYTHING variable, used to represent the set of
6360 variables stored to *ANYTHING. */
6361 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6362 gcc_assert (var_storedanything->id == storedanything_id);
6363 var_storedanything->is_artificial_var = 1;
6364 var_storedanything->offset = 0;
6365 var_storedanything->size = ~0;
6366 var_storedanything->fullsize = ~0;
6367 var_storedanything->is_special_var = 0;
6369 /* Create the INTEGER variable, used to represent that a variable points
6370 to what an INTEGER "points to". */
6371 var_integer = new_var_info (NULL_TREE, "INTEGER");
6372 gcc_assert (var_integer->id == integer_id);
6373 var_integer->is_artificial_var = 1;
6374 var_integer->size = ~0;
6375 var_integer->fullsize = ~0;
6376 var_integer->offset = 0;
6377 var_integer->next = NULL;
6378 var_integer->is_special_var = 1;
6380 /* INTEGER = ANYTHING, because we don't know where a dereference of
6381 a random integer will point to. */
6383 lhs.var = integer_id;
6385 rhs.type = ADDRESSOF;
6386 rhs.var = anything_id;
6388 process_constraint (new_constraint (lhs, rhs));
6391 /* Initialize things necessary to perform PTA */
6394 init_alias_vars (void)
6396 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6398 bitmap_obstack_initialize (&pta_obstack);
6399 bitmap_obstack_initialize (&oldpta_obstack);
6400 bitmap_obstack_initialize (&predbitmap_obstack);
6402 constraint_pool = create_alloc_pool ("Constraint pool",
6403 sizeof (struct constraint), 30);
6404 variable_info_pool = create_alloc_pool ("Variable info pool",
6405 sizeof (struct variable_info), 30);
6406 constraints = VEC_alloc (constraint_t, heap, 8);
6407 varmap = VEC_alloc (varinfo_t, heap, 8);
6408 vi_for_tree = pointer_map_create ();
6409 call_stmt_vars = pointer_map_create ();
6411 memset (&stats, 0, sizeof (stats));
6412 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6413 shared_bitmap_eq, free);
6416 gcc_obstack_init (&fake_var_decl_obstack);
6419 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6420 predecessor edges. */
6423 remove_preds_and_fake_succs (constraint_graph_t graph)
6427 /* Clear the implicit ref and address nodes from the successor
6429 for (i = 0; i < FIRST_REF_NODE; i++)
6431 if (graph->succs[i])
6432 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6433 FIRST_REF_NODE * 2);
6436 /* Free the successor list for the non-ref nodes. */
6437 for (i = FIRST_REF_NODE; i < graph->size; i++)
6439 if (graph->succs[i])
6440 BITMAP_FREE (graph->succs[i]);
6443 /* Now reallocate the size of the successor list as, and blow away
6444 the predecessor bitmaps. */
6445 graph->size = VEC_length (varinfo_t, varmap);
6446 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6448 free (graph->implicit_preds);
6449 graph->implicit_preds = NULL;
6450 free (graph->preds);
6451 graph->preds = NULL;
6452 bitmap_obstack_release (&predbitmap_obstack);
6455 /* Solve the constraint set. */
6458 solve_constraints (void)
6460 struct scc_info *si;
6464 "\nCollapsing static cycles and doing variable "
6467 init_graph (VEC_length (varinfo_t, varmap) * 2);
6470 fprintf (dump_file, "Building predecessor graph\n");
6471 build_pred_graph ();
6474 fprintf (dump_file, "Detecting pointer and location "
6476 si = perform_var_substitution (graph);
6479 fprintf (dump_file, "Rewriting constraints and unifying "
6481 rewrite_constraints (graph, si);
6483 build_succ_graph ();
6485 free_var_substitution_info (si);
6487 /* Attach complex constraints to graph nodes. */
6488 move_complex_constraints (graph);
6491 fprintf (dump_file, "Uniting pointer but not location equivalent "
6493 unite_pointer_equivalences (graph);
6496 fprintf (dump_file, "Finding indirect cycles\n");
6497 find_indirect_cycles (graph);
6499 /* Implicit nodes and predecessors are no longer necessary at this
6501 remove_preds_and_fake_succs (graph);
6503 if (dump_file && (dump_flags & TDF_GRAPH))
6505 fprintf (dump_file, "\n\n// The constraint graph before solve-graph "
6506 "in dot format:\n");
6507 dump_constraint_graph (dump_file);
6508 fprintf (dump_file, "\n\n");
6512 fprintf (dump_file, "Solving graph\n");
6514 solve_graph (graph);
6516 if (dump_file && (dump_flags & TDF_GRAPH))
6518 fprintf (dump_file, "\n\n// The constraint graph after solve-graph "
6519 "in dot format:\n");
6520 dump_constraint_graph (dump_file);
6521 fprintf (dump_file, "\n\n");
6525 dump_sa_points_to_info (dump_file);
6528 /* Create points-to sets for the current function. See the comments
6529 at the start of the file for an algorithmic overview. */
6532 compute_points_to_sets (void)
6538 timevar_push (TV_TREE_PTA);
6542 intra_create_variable_infos ();
6544 /* Now walk all statements and build the constraint set. */
6547 gimple_stmt_iterator gsi;
6549 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6551 gimple phi = gsi_stmt (gsi);
6553 if (is_gimple_reg (gimple_phi_result (phi)))
6554 find_func_aliases (phi);
6557 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6559 gimple stmt = gsi_stmt (gsi);
6561 find_func_aliases (stmt);
6567 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6568 dump_constraints (dump_file, 0);
6571 /* From the constraints compute the points-to sets. */
6572 solve_constraints ();
6574 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6575 find_what_var_points_to (get_varinfo (escaped_id),
6576 &cfun->gimple_df->escaped);
6578 /* Make sure the ESCAPED solution (which is used as placeholder in
6579 other solutions) does not reference itself. This simplifies
6580 points-to solution queries. */
6581 cfun->gimple_df->escaped.escaped = 0;
6583 /* Mark escaped HEAP variables as global. */
6584 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6586 && !vi->is_restrict_var
6587 && !vi->is_global_var)
6588 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6589 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6591 /* Compute the points-to sets for pointer SSA_NAMEs. */
6592 for (i = 0; i < num_ssa_names; ++i)
6594 tree ptr = ssa_name (i);
6596 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6597 find_what_p_points_to (ptr);
6600 /* Compute the call-used/clobbered sets. */
6603 gimple_stmt_iterator gsi;
6605 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6607 gimple stmt = gsi_stmt (gsi);
6608 struct pt_solution *pt;
6609 if (!is_gimple_call (stmt))
6612 pt = gimple_call_use_set (stmt);
6613 if (gimple_call_flags (stmt) & ECF_CONST)
6614 memset (pt, 0, sizeof (struct pt_solution));
6615 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6617 find_what_var_points_to (vi, pt);
6618 /* Escaped (and thus nonlocal) variables are always
6619 implicitly used by calls. */
6620 /* ??? ESCAPED can be empty even though NONLOCAL
6627 /* If there is nothing special about this call then
6628 we have made everything that is used also escape. */
6629 *pt = cfun->gimple_df->escaped;
6633 pt = gimple_call_clobber_set (stmt);
6634 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6635 memset (pt, 0, sizeof (struct pt_solution));
6636 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6638 find_what_var_points_to (vi, pt);
6639 /* Escaped (and thus nonlocal) variables are always
6640 implicitly clobbered by calls. */
6641 /* ??? ESCAPED can be empty even though NONLOCAL
6648 /* If there is nothing special about this call then
6649 we have made everything that is used also escape. */
6650 *pt = cfun->gimple_df->escaped;
6656 timevar_pop (TV_TREE_PTA);
6660 /* Delete created points-to sets. */
6663 delete_points_to_sets (void)
6667 htab_delete (shared_bitmap_table);
6668 if (dump_file && (dump_flags & TDF_STATS))
6669 fprintf (dump_file, "Points to sets created:%d\n",
6670 stats.points_to_sets_created);
6672 pointer_map_destroy (vi_for_tree);
6673 pointer_map_destroy (call_stmt_vars);
6674 bitmap_obstack_release (&pta_obstack);
6675 VEC_free (constraint_t, heap, constraints);
6677 for (i = 0; i < graph->size; i++)
6678 VEC_free (constraint_t, heap, graph->complex[i]);
6679 free (graph->complex);
6682 free (graph->succs);
6684 free (graph->pe_rep);
6685 free (graph->indirect_cycles);
6688 VEC_free (varinfo_t, heap, varmap);
6689 free_alloc_pool (variable_info_pool);
6690 free_alloc_pool (constraint_pool);
6692 obstack_free (&fake_var_decl_obstack, NULL);
6696 /* Compute points-to information for every SSA_NAME pointer in the
6697 current function and compute the transitive closure of escaped
6698 variables to re-initialize the call-clobber states of local variables. */
6701 compute_may_aliases (void)
6703 if (cfun->gimple_df->ipa_pta)
6707 fprintf (dump_file, "\nNot re-computing points-to information "
6708 "because IPA points-to information is available.\n\n");
6710 /* But still dump what we have remaining it. */
6711 dump_alias_info (dump_file);
6713 if (dump_flags & TDF_DETAILS)
6714 dump_referenced_vars (dump_file);
6720 /* For each pointer P_i, determine the sets of variables that P_i may
6721 point-to. Compute the reachability set of escaped and call-used
6723 compute_points_to_sets ();
6725 /* Debugging dumps. */
6728 dump_alias_info (dump_file);
6730 if (dump_flags & TDF_DETAILS)
6731 dump_referenced_vars (dump_file);
6734 /* Deallocate memory used by aliasing data structures and the internal
6735 points-to solution. */
6736 delete_points_to_sets ();
6738 gcc_assert (!need_ssa_update_p (cfun));
6744 gate_tree_pta (void)
6746 return flag_tree_pta;
6749 /* A dummy pass to cause points-to information to be computed via
6750 TODO_rebuild_alias. */
6752 struct gimple_opt_pass pass_build_alias =
6757 gate_tree_pta, /* gate */
6761 0, /* static_pass_number */
6762 TV_NONE, /* tv_id */
6763 PROP_cfg | PROP_ssa, /* properties_required */
6764 0, /* properties_provided */
6765 0, /* properties_destroyed */
6766 0, /* todo_flags_start */
6767 TODO_rebuild_alias /* todo_flags_finish */
6771 /* A dummy pass to cause points-to information to be computed via
6772 TODO_rebuild_alias. */
6774 struct gimple_opt_pass pass_build_ealias =
6778 "ealias", /* name */
6779 gate_tree_pta, /* gate */
6783 0, /* static_pass_number */
6784 TV_NONE, /* tv_id */
6785 PROP_cfg | PROP_ssa, /* properties_required */
6786 0, /* properties_provided */
6787 0, /* properties_destroyed */
6788 0, /* todo_flags_start */
6789 TODO_rebuild_alias /* todo_flags_finish */
6794 /* Return true if we should execute IPA PTA. */
6800 /* Don't bother doing anything if the program has errors. */
6804 /* IPA PTA solutions for ESCAPED. */
6805 struct pt_solution ipa_escaped_pt
6806 = { true, false, false, false, false, false, false, NULL };
6808 /* Associate node with varinfo DATA. Worker for
6809 cgraph_for_node_and_aliases. */
6811 associate_varinfo_to_alias (struct cgraph_node *node, void *data)
6813 if (node->alias || node->thunk.thunk_p)
6814 insert_vi_for_tree (node->decl, (varinfo_t)data);
6818 /* Execute the driver for IPA PTA. */
6820 ipa_pta_execute (void)
6822 struct cgraph_node *node;
6823 struct varpool_node *var;
6830 if (dump_file && (dump_flags & TDF_DETAILS))
6832 dump_cgraph (dump_file);
6833 fprintf (dump_file, "\n");
6836 /* Build the constraints. */
6837 for (node = cgraph_nodes; node; node = node->next)
6840 /* Nodes without a body are not interesting. Especially do not
6841 visit clones at this point for now - we get duplicate decls
6842 there for inline clones at least. */
6843 if (!cgraph_function_with_gimple_body_p (node))
6846 gcc_assert (!node->clone_of);
6848 vi = create_function_info_for (node->decl,
6849 alias_get_name (node->decl));
6850 cgraph_for_node_and_aliases (node, associate_varinfo_to_alias, vi, true);
6853 /* Create constraints for global variables and their initializers. */
6854 for (var = varpool_nodes; var; var = var->next)
6859 get_vi_for_tree (var->decl);
6865 "Generating constraints for global initializers\n\n");
6866 dump_constraints (dump_file, 0);
6867 fprintf (dump_file, "\n");
6869 from = VEC_length (constraint_t, constraints);
6871 for (node = cgraph_nodes; node; node = node->next)
6873 struct function *func;
6877 /* Nodes without a body are not interesting. */
6878 if (!cgraph_function_with_gimple_body_p (node))
6884 "Generating constraints for %s", cgraph_node_name (node));
6885 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6886 fprintf (dump_file, " (%s)",
6887 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6888 fprintf (dump_file, "\n");
6891 func = DECL_STRUCT_FUNCTION (node->decl);
6892 old_func_decl = current_function_decl;
6894 current_function_decl = node->decl;
6896 /* For externally visible or attribute used annotated functions use
6897 local constraints for their arguments.
6898 For local functions we see all callers and thus do not need initial
6899 constraints for parameters. */
6900 if (node->reachable_from_other_partition
6901 || node->local.externally_visible
6904 intra_create_variable_infos ();
6906 /* We also need to make function return values escape. Nothing
6907 escapes by returning from main though. */
6908 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6911 fi = lookup_vi_for_tree (node->decl);
6912 rvi = first_vi_for_offset (fi, fi_result);
6913 if (rvi && rvi->offset == fi_result)
6915 struct constraint_expr includes;
6916 struct constraint_expr var;
6917 includes.var = escaped_id;
6918 includes.offset = 0;
6919 includes.type = SCALAR;
6923 process_constraint (new_constraint (includes, var));
6928 /* Build constriants for the function body. */
6929 FOR_EACH_BB_FN (bb, func)
6931 gimple_stmt_iterator gsi;
6933 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6936 gimple phi = gsi_stmt (gsi);
6938 if (is_gimple_reg (gimple_phi_result (phi)))
6939 find_func_aliases (phi);
6942 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6944 gimple stmt = gsi_stmt (gsi);
6946 find_func_aliases (stmt);
6947 find_func_clobbers (stmt);
6951 current_function_decl = old_func_decl;
6956 fprintf (dump_file, "\n");
6957 dump_constraints (dump_file, from);
6958 fprintf (dump_file, "\n");
6960 from = VEC_length (constraint_t, constraints);
6963 /* From the constraints compute the points-to sets. */
6964 solve_constraints ();
6966 /* Compute the global points-to sets for ESCAPED.
6967 ??? Note that the computed escape set is not correct
6968 for the whole unit as we fail to consider graph edges to
6969 externally visible functions. */
6970 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6972 /* Make sure the ESCAPED solution (which is used as placeholder in
6973 other solutions) does not reference itself. This simplifies
6974 points-to solution queries. */
6975 ipa_escaped_pt.ipa_escaped = 0;
6977 /* Assign the points-to sets to the SSA names in the unit. */
6978 for (node = cgraph_nodes; node; node = node->next)
6981 struct function *fn;
6985 struct pt_solution uses, clobbers;
6986 struct cgraph_edge *e;
6988 /* Nodes without a body are not interesting. */
6989 if (!cgraph_function_with_gimple_body_p (node))
6992 fn = DECL_STRUCT_FUNCTION (node->decl);
6994 /* Compute the points-to sets for pointer SSA_NAMEs. */
6995 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6998 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6999 find_what_p_points_to (ptr);
7002 /* Compute the call-use and call-clobber sets for all direct calls. */
7003 fi = lookup_vi_for_tree (node->decl);
7004 gcc_assert (fi->is_fn_info);
7005 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
7007 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
7008 for (e = node->callers; e; e = e->next_caller)
7013 *gimple_call_clobber_set (e->call_stmt) = clobbers;
7014 *gimple_call_use_set (e->call_stmt) = uses;
7017 /* Compute the call-use and call-clobber sets for indirect calls
7018 and calls to external functions. */
7019 FOR_EACH_BB_FN (bb, fn)
7021 gimple_stmt_iterator gsi;
7023 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
7025 gimple stmt = gsi_stmt (gsi);
7026 struct pt_solution *pt;
7030 if (!is_gimple_call (stmt))
7033 /* Handle direct calls to external functions. */
7034 decl = gimple_call_fndecl (stmt);
7036 && (!(fi = lookup_vi_for_tree (decl))
7037 || !fi->is_fn_info))
7039 pt = gimple_call_use_set (stmt);
7040 if (gimple_call_flags (stmt) & ECF_CONST)
7041 memset (pt, 0, sizeof (struct pt_solution));
7042 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
7044 find_what_var_points_to (vi, pt);
7045 /* Escaped (and thus nonlocal) variables are always
7046 implicitly used by calls. */
7047 /* ??? ESCAPED can be empty even though NONLOCAL
7050 pt->ipa_escaped = 1;
7054 /* If there is nothing special about this call then
7055 we have made everything that is used also escape. */
7056 *pt = ipa_escaped_pt;
7060 pt = gimple_call_clobber_set (stmt);
7061 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
7062 memset (pt, 0, sizeof (struct pt_solution));
7063 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
7065 find_what_var_points_to (vi, pt);
7066 /* Escaped (and thus nonlocal) variables are always
7067 implicitly clobbered by calls. */
7068 /* ??? ESCAPED can be empty even though NONLOCAL
7071 pt->ipa_escaped = 1;
7075 /* If there is nothing special about this call then
7076 we have made everything that is used also escape. */
7077 *pt = ipa_escaped_pt;
7082 /* Handle indirect calls. */
7084 && (fi = get_fi_for_callee (stmt)))
7086 /* We need to accumulate all clobbers/uses of all possible
7088 fi = get_varinfo (find (fi->id));
7089 /* If we cannot constrain the set of functions we'll end up
7090 calling we end up using/clobbering everything. */
7091 if (bitmap_bit_p (fi->solution, anything_id)
7092 || bitmap_bit_p (fi->solution, nonlocal_id)
7093 || bitmap_bit_p (fi->solution, escaped_id))
7095 pt_solution_reset (gimple_call_clobber_set (stmt));
7096 pt_solution_reset (gimple_call_use_set (stmt));
7102 struct pt_solution *uses, *clobbers;
7104 uses = gimple_call_use_set (stmt);
7105 clobbers = gimple_call_clobber_set (stmt);
7106 memset (uses, 0, sizeof (struct pt_solution));
7107 memset (clobbers, 0, sizeof (struct pt_solution));
7108 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7110 struct pt_solution sol;
7112 vi = get_varinfo (i);
7113 if (!vi->is_fn_info)
7115 /* ??? We could be more precise here? */
7117 uses->ipa_escaped = 1;
7118 clobbers->nonlocal = 1;
7119 clobbers->ipa_escaped = 1;
7123 if (!uses->anything)
7125 find_what_var_points_to
7126 (first_vi_for_offset (vi, fi_uses), &sol);
7127 pt_solution_ior_into (uses, &sol);
7129 if (!clobbers->anything)
7131 find_what_var_points_to
7132 (first_vi_for_offset (vi, fi_clobbers), &sol);
7133 pt_solution_ior_into (clobbers, &sol);
7141 fn->gimple_df->ipa_pta = true;
7144 delete_points_to_sets ();
7151 struct simple_ipa_opt_pass pass_ipa_pta =
7156 gate_ipa_pta, /* gate */
7157 ipa_pta_execute, /* execute */
7160 0, /* static_pass_number */
7161 TV_IPA_PTA, /* tv_id */
7162 0, /* properties_required */
7163 0, /* properties_provided */
7164 0, /* properties_destroyed */
7165 0, /* todo_flags_start */
7166 TODO_update_ssa /* todo_flags_finish */