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 = BITMAP_ALLOC (&oldpta_obstack);
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 BITMAP_FREE (get_varinfo (from)->oldsolution);
1509 if (stats.iterations > 0)
1511 BITMAP_FREE (get_varinfo (to)->oldsolution);
1512 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1515 if (valid_graph_edge (graph, to, to))
1517 if (graph->succs[to])
1518 bitmap_clear_bit (graph->succs[to], to);
1522 /* Information needed to compute the topological ordering of a graph. */
1526 /* sbitmap of visited nodes. */
1528 /* Array that stores the topological order of the graph, *in
1530 VEC(unsigned,heap) *topo_order;
1534 /* Initialize and return a topological info structure. */
1536 static struct topo_info *
1537 init_topo_info (void)
1539 size_t size = graph->size;
1540 struct topo_info *ti = XNEW (struct topo_info);
1541 ti->visited = sbitmap_alloc (size);
1542 sbitmap_zero (ti->visited);
1543 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1548 /* Free the topological sort info pointed to by TI. */
1551 free_topo_info (struct topo_info *ti)
1553 sbitmap_free (ti->visited);
1554 VEC_free (unsigned, heap, ti->topo_order);
1558 /* Visit the graph in topological order, and store the order in the
1559 topo_info structure. */
1562 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1568 SET_BIT (ti->visited, n);
1570 if (graph->succs[n])
1571 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1573 if (!TEST_BIT (ti->visited, j))
1574 topo_visit (graph, ti, j);
1577 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1580 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1581 starting solution for y. */
1584 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1587 unsigned int lhs = c->lhs.var;
1589 bitmap sol = get_varinfo (lhs)->solution;
1592 HOST_WIDE_INT roffset = c->rhs.offset;
1594 /* Our IL does not allow this. */
1595 gcc_assert (c->lhs.offset == 0);
1597 /* If the solution of Y contains anything it is good enough to transfer
1599 if (bitmap_bit_p (delta, anything_id))
1601 flag |= bitmap_set_bit (sol, anything_id);
1605 /* If we do not know at with offset the rhs is dereferenced compute
1606 the reachability set of DELTA, conservatively assuming it is
1607 dereferenced at all valid offsets. */
1608 if (roffset == UNKNOWN_OFFSET)
1610 solution_set_expand (delta, delta);
1611 /* No further offset processing is necessary. */
1615 /* For each variable j in delta (Sol(y)), add
1616 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1617 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1619 varinfo_t v = get_varinfo (j);
1620 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1624 fieldoffset = v->offset;
1625 else if (roffset != 0)
1626 v = first_vi_for_offset (v, fieldoffset);
1627 /* If the access is outside of the variable we can ignore it. */
1635 /* Adding edges from the special vars is pointless.
1636 They don't have sets that can change. */
1637 if (get_varinfo (t)->is_special_var)
1638 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1639 /* Merging the solution from ESCAPED needlessly increases
1640 the set. Use ESCAPED as representative instead. */
1641 else if (v->id == escaped_id)
1642 flag |= bitmap_set_bit (sol, escaped_id);
1643 else if (v->may_have_pointers
1644 && add_graph_edge (graph, lhs, t))
1645 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1647 /* If the variable is not exactly at the requested offset
1648 we have to include the next one. */
1649 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1654 fieldoffset = v->offset;
1660 /* If the LHS solution changed, mark the var as changed. */
1663 get_varinfo (lhs)->solution = sol;
1664 bitmap_set_bit (changed, lhs);
1668 /* Process a constraint C that represents *(x + off) = y using DELTA
1669 as the starting solution for x. */
1672 do_ds_constraint (constraint_t c, bitmap delta)
1674 unsigned int rhs = c->rhs.var;
1675 bitmap sol = get_varinfo (rhs)->solution;
1678 HOST_WIDE_INT loff = c->lhs.offset;
1679 bool escaped_p = false;
1681 /* Our IL does not allow this. */
1682 gcc_assert (c->rhs.offset == 0);
1684 /* If the solution of y contains ANYTHING simply use the ANYTHING
1685 solution. This avoids needlessly increasing the points-to sets. */
1686 if (bitmap_bit_p (sol, anything_id))
1687 sol = get_varinfo (find (anything_id))->solution;
1689 /* If the solution for x contains ANYTHING we have to merge the
1690 solution of y into all pointer variables which we do via
1692 if (bitmap_bit_p (delta, anything_id))
1694 unsigned t = find (storedanything_id);
1695 if (add_graph_edge (graph, t, rhs))
1697 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1698 bitmap_set_bit (changed, t);
1703 /* If we do not know at with offset the rhs is dereferenced compute
1704 the reachability set of DELTA, conservatively assuming it is
1705 dereferenced at all valid offsets. */
1706 if (loff == UNKNOWN_OFFSET)
1708 solution_set_expand (delta, delta);
1712 /* For each member j of delta (Sol(x)), add an edge from y to j and
1713 union Sol(y) into Sol(j) */
1714 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1716 varinfo_t v = get_varinfo (j);
1718 HOST_WIDE_INT fieldoffset = v->offset + loff;
1721 fieldoffset = v->offset;
1723 v = first_vi_for_offset (v, fieldoffset);
1724 /* If the access is outside of the variable we can ignore it. */
1730 if (v->may_have_pointers)
1732 /* If v is a global variable then this is an escape point. */
1733 if (v->is_global_var
1736 t = find (escaped_id);
1737 if (add_graph_edge (graph, t, rhs)
1738 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1739 bitmap_set_bit (changed, t);
1740 /* Enough to let rhs escape once. */
1744 if (v->is_special_var)
1748 if (add_graph_edge (graph, t, rhs)
1749 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1750 bitmap_set_bit (changed, t);
1753 /* If the variable is not exactly at the requested offset
1754 we have to include the next one. */
1755 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1760 fieldoffset = v->offset;
1766 /* Handle a non-simple (simple meaning requires no iteration),
1767 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1770 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1772 if (c->lhs.type == DEREF)
1774 if (c->rhs.type == ADDRESSOF)
1781 do_ds_constraint (c, delta);
1784 else if (c->rhs.type == DEREF)
1787 if (!(get_varinfo (c->lhs.var)->is_special_var))
1788 do_sd_constraint (graph, c, delta);
1796 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1797 solution = get_varinfo (c->rhs.var)->solution;
1798 tmp = get_varinfo (c->lhs.var)->solution;
1800 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1804 get_varinfo (c->lhs.var)->solution = tmp;
1805 bitmap_set_bit (changed, c->lhs.var);
1810 /* Initialize and return a new SCC info structure. */
1812 static struct scc_info *
1813 init_scc_info (size_t size)
1815 struct scc_info *si = XNEW (struct scc_info);
1818 si->current_index = 0;
1819 si->visited = sbitmap_alloc (size);
1820 sbitmap_zero (si->visited);
1821 si->deleted = sbitmap_alloc (size);
1822 sbitmap_zero (si->deleted);
1823 si->node_mapping = XNEWVEC (unsigned int, size);
1824 si->dfs = XCNEWVEC (unsigned int, size);
1826 for (i = 0; i < size; i++)
1827 si->node_mapping[i] = i;
1829 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1833 /* Free an SCC info structure pointed to by SI */
1836 free_scc_info (struct scc_info *si)
1838 sbitmap_free (si->visited);
1839 sbitmap_free (si->deleted);
1840 free (si->node_mapping);
1842 VEC_free (unsigned, heap, si->scc_stack);
1847 /* Find indirect cycles in GRAPH that occur, using strongly connected
1848 components, and note them in the indirect cycles map.
1850 This technique comes from Ben Hardekopf and Calvin Lin,
1851 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1852 Lines of Code", submitted to PLDI 2007. */
1855 find_indirect_cycles (constraint_graph_t graph)
1858 unsigned int size = graph->size;
1859 struct scc_info *si = init_scc_info (size);
1861 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1862 if (!TEST_BIT (si->visited, i) && find (i) == i)
1863 scc_visit (graph, si, i);
1868 /* Compute a topological ordering for GRAPH, and store the result in the
1869 topo_info structure TI. */
1872 compute_topo_order (constraint_graph_t graph,
1873 struct topo_info *ti)
1876 unsigned int size = graph->size;
1878 for (i = 0; i != size; ++i)
1879 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1880 topo_visit (graph, ti, i);
1883 /* Structure used to for hash value numbering of pointer equivalence
1886 typedef struct equiv_class_label
1889 unsigned int equivalence_class;
1891 } *equiv_class_label_t;
1892 typedef const struct equiv_class_label *const_equiv_class_label_t;
1894 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1896 static htab_t pointer_equiv_class_table;
1898 /* A hashtable for mapping a bitmap of labels->location equivalence
1900 static htab_t location_equiv_class_table;
1902 /* Hash function for a equiv_class_label_t */
1905 equiv_class_label_hash (const void *p)
1907 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1908 return ecl->hashcode;
1911 /* Equality function for two equiv_class_label_t's. */
1914 equiv_class_label_eq (const void *p1, const void *p2)
1916 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1917 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1918 return (eql1->hashcode == eql2->hashcode
1919 && bitmap_equal_p (eql1->labels, eql2->labels));
1922 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1926 equiv_class_lookup (htab_t table, bitmap labels)
1929 struct equiv_class_label ecl;
1931 ecl.labels = labels;
1932 ecl.hashcode = bitmap_hash (labels);
1934 slot = htab_find_slot_with_hash (table, &ecl,
1935 ecl.hashcode, NO_INSERT);
1939 return ((equiv_class_label_t) *slot)->equivalence_class;
1943 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1947 equiv_class_add (htab_t table, unsigned int equivalence_class,
1951 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1953 ecl->labels = labels;
1954 ecl->equivalence_class = equivalence_class;
1955 ecl->hashcode = bitmap_hash (labels);
1957 slot = htab_find_slot_with_hash (table, ecl,
1958 ecl->hashcode, INSERT);
1959 gcc_assert (!*slot);
1960 *slot = (void *) ecl;
1963 /* Perform offline variable substitution.
1965 This is a worst case quadratic time way of identifying variables
1966 that must have equivalent points-to sets, including those caused by
1967 static cycles, and single entry subgraphs, in the constraint graph.
1969 The technique is described in "Exploiting Pointer and Location
1970 Equivalence to Optimize Pointer Analysis. In the 14th International
1971 Static Analysis Symposium (SAS), August 2007." It is known as the
1972 "HU" algorithm, and is equivalent to value numbering the collapsed
1973 constraint graph including evaluating unions.
1975 The general method of finding equivalence classes is as follows:
1976 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1977 Initialize all non-REF nodes to be direct nodes.
1978 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1980 For each constraint containing the dereference, we also do the same
1983 We then compute SCC's in the graph and unify nodes in the same SCC,
1986 For each non-collapsed node x:
1987 Visit all unvisited explicit incoming edges.
1988 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1990 Lookup the equivalence class for pts(x).
1991 If we found one, equivalence_class(x) = found class.
1992 Otherwise, equivalence_class(x) = new class, and new_class is
1993 added to the lookup table.
1995 All direct nodes with the same equivalence class can be replaced
1996 with a single representative node.
1997 All unlabeled nodes (label == 0) are not pointers and all edges
1998 involving them can be eliminated.
1999 We perform these optimizations during rewrite_constraints
2001 In addition to pointer equivalence class finding, we also perform
2002 location equivalence class finding. This is the set of variables
2003 that always appear together in points-to sets. We use this to
2004 compress the size of the points-to sets. */
2006 /* Current maximum pointer equivalence class id. */
2007 static int pointer_equiv_class;
2009 /* Current maximum location equivalence class id. */
2010 static int location_equiv_class;
2012 /* Recursive routine to find strongly connected components in GRAPH,
2013 and label it's nodes with DFS numbers. */
2016 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2020 unsigned int my_dfs;
2022 gcc_assert (si->node_mapping[n] == n);
2023 SET_BIT (si->visited, n);
2024 si->dfs[n] = si->current_index ++;
2025 my_dfs = si->dfs[n];
2027 /* Visit all the successors. */
2028 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2030 unsigned int w = si->node_mapping[i];
2032 if (TEST_BIT (si->deleted, w))
2035 if (!TEST_BIT (si->visited, w))
2036 condense_visit (graph, si, w);
2038 unsigned int t = si->node_mapping[w];
2039 unsigned int nnode = si->node_mapping[n];
2040 gcc_assert (nnode == n);
2042 if (si->dfs[t] < si->dfs[nnode])
2043 si->dfs[n] = si->dfs[t];
2047 /* Visit all the implicit predecessors. */
2048 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2050 unsigned int w = si->node_mapping[i];
2052 if (TEST_BIT (si->deleted, w))
2055 if (!TEST_BIT (si->visited, w))
2056 condense_visit (graph, si, w);
2058 unsigned int t = si->node_mapping[w];
2059 unsigned int nnode = si->node_mapping[n];
2060 gcc_assert (nnode == n);
2062 if (si->dfs[t] < si->dfs[nnode])
2063 si->dfs[n] = si->dfs[t];
2067 /* See if any components have been identified. */
2068 if (si->dfs[n] == my_dfs)
2070 while (VEC_length (unsigned, si->scc_stack) != 0
2071 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2073 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2074 si->node_mapping[w] = n;
2076 if (!TEST_BIT (graph->direct_nodes, w))
2077 RESET_BIT (graph->direct_nodes, n);
2079 /* Unify our nodes. */
2080 if (graph->preds[w])
2082 if (!graph->preds[n])
2083 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2084 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2086 if (graph->implicit_preds[w])
2088 if (!graph->implicit_preds[n])
2089 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2090 bitmap_ior_into (graph->implicit_preds[n],
2091 graph->implicit_preds[w]);
2093 if (graph->points_to[w])
2095 if (!graph->points_to[n])
2096 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2097 bitmap_ior_into (graph->points_to[n],
2098 graph->points_to[w]);
2101 SET_BIT (si->deleted, n);
2104 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2107 /* Label pointer equivalences. */
2110 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2114 SET_BIT (si->visited, n);
2116 if (!graph->points_to[n])
2117 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2119 /* Label and union our incoming edges's points to sets. */
2120 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2122 unsigned int w = si->node_mapping[i];
2123 if (!TEST_BIT (si->visited, w))
2124 label_visit (graph, si, w);
2126 /* Skip unused edges */
2127 if (w == n || graph->pointer_label[w] == 0)
2130 if (graph->points_to[w])
2131 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2133 /* Indirect nodes get fresh variables. */
2134 if (!TEST_BIT (graph->direct_nodes, n))
2135 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2137 if (!bitmap_empty_p (graph->points_to[n]))
2139 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2140 graph->points_to[n]);
2143 label = pointer_equiv_class++;
2144 equiv_class_add (pointer_equiv_class_table,
2145 label, graph->points_to[n]);
2147 graph->pointer_label[n] = label;
2151 /* Perform offline variable substitution, discovering equivalence
2152 classes, and eliminating non-pointer variables. */
2154 static struct scc_info *
2155 perform_var_substitution (constraint_graph_t graph)
2158 unsigned int size = graph->size;
2159 struct scc_info *si = init_scc_info (size);
2161 bitmap_obstack_initialize (&iteration_obstack);
2162 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2163 equiv_class_label_eq, free);
2164 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2165 equiv_class_label_eq, free);
2166 pointer_equiv_class = 1;
2167 location_equiv_class = 1;
2169 /* Condense the nodes, which means to find SCC's, count incoming
2170 predecessors, and unite nodes in SCC's. */
2171 for (i = 0; i < FIRST_REF_NODE; i++)
2172 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2173 condense_visit (graph, si, si->node_mapping[i]);
2175 sbitmap_zero (si->visited);
2176 /* Actually the label the nodes for pointer equivalences */
2177 for (i = 0; i < FIRST_REF_NODE; i++)
2178 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2179 label_visit (graph, si, si->node_mapping[i]);
2181 /* Calculate location equivalence labels. */
2182 for (i = 0; i < FIRST_REF_NODE; i++)
2189 if (!graph->pointed_by[i])
2191 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2193 /* Translate the pointed-by mapping for pointer equivalence
2195 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2197 bitmap_set_bit (pointed_by,
2198 graph->pointer_label[si->node_mapping[j]]);
2200 /* The original pointed_by is now dead. */
2201 BITMAP_FREE (graph->pointed_by[i]);
2203 /* Look up the location equivalence label if one exists, or make
2205 label = equiv_class_lookup (location_equiv_class_table,
2209 label = location_equiv_class++;
2210 equiv_class_add (location_equiv_class_table,
2215 if (dump_file && (dump_flags & TDF_DETAILS))
2216 fprintf (dump_file, "Found location equivalence for node %s\n",
2217 get_varinfo (i)->name);
2218 BITMAP_FREE (pointed_by);
2220 graph->loc_label[i] = label;
2224 if (dump_file && (dump_flags & TDF_DETAILS))
2225 for (i = 0; i < FIRST_REF_NODE; i++)
2227 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2229 "Equivalence classes for %s node id %d:%s are pointer: %d"
2231 direct_node ? "Direct node" : "Indirect node", i,
2232 get_varinfo (i)->name,
2233 graph->pointer_label[si->node_mapping[i]],
2234 graph->loc_label[si->node_mapping[i]]);
2237 /* Quickly eliminate our non-pointer variables. */
2239 for (i = 0; i < FIRST_REF_NODE; i++)
2241 unsigned int node = si->node_mapping[i];
2243 if (graph->pointer_label[node] == 0)
2245 if (dump_file && (dump_flags & TDF_DETAILS))
2247 "%s is a non-pointer variable, eliminating edges.\n",
2248 get_varinfo (node)->name);
2249 stats.nonpointer_vars++;
2250 clear_edges_for_node (graph, node);
2257 /* Free information that was only necessary for variable
2261 free_var_substitution_info (struct scc_info *si)
2264 free (graph->pointer_label);
2265 free (graph->loc_label);
2266 free (graph->pointed_by);
2267 free (graph->points_to);
2268 free (graph->eq_rep);
2269 sbitmap_free (graph->direct_nodes);
2270 htab_delete (pointer_equiv_class_table);
2271 htab_delete (location_equiv_class_table);
2272 bitmap_obstack_release (&iteration_obstack);
2275 /* Return an existing node that is equivalent to NODE, which has
2276 equivalence class LABEL, if one exists. Return NODE otherwise. */
2279 find_equivalent_node (constraint_graph_t graph,
2280 unsigned int node, unsigned int label)
2282 /* If the address version of this variable is unused, we can
2283 substitute it for anything else with the same label.
2284 Otherwise, we know the pointers are equivalent, but not the
2285 locations, and we can unite them later. */
2287 if (!bitmap_bit_p (graph->address_taken, node))
2289 gcc_assert (label < graph->size);
2291 if (graph->eq_rep[label] != -1)
2293 /* Unify the two variables since we know they are equivalent. */
2294 if (unite (graph->eq_rep[label], node))
2295 unify_nodes (graph, graph->eq_rep[label], node, false);
2296 return graph->eq_rep[label];
2300 graph->eq_rep[label] = node;
2301 graph->pe_rep[label] = node;
2306 gcc_assert (label < graph->size);
2307 graph->pe[node] = label;
2308 if (graph->pe_rep[label] == -1)
2309 graph->pe_rep[label] = node;
2315 /* Unite pointer equivalent but not location equivalent nodes in
2316 GRAPH. This may only be performed once variable substitution is
2320 unite_pointer_equivalences (constraint_graph_t graph)
2324 /* Go through the pointer equivalences and unite them to their
2325 representative, if they aren't already. */
2326 for (i = 0; i < FIRST_REF_NODE; i++)
2328 unsigned int label = graph->pe[i];
2331 int label_rep = graph->pe_rep[label];
2333 if (label_rep == -1)
2336 label_rep = find (label_rep);
2337 if (label_rep >= 0 && unite (label_rep, find (i)))
2338 unify_nodes (graph, label_rep, i, false);
2343 /* Move complex constraints to the GRAPH nodes they belong to. */
2346 move_complex_constraints (constraint_graph_t graph)
2351 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2355 struct constraint_expr lhs = c->lhs;
2356 struct constraint_expr rhs = c->rhs;
2358 if (lhs.type == DEREF)
2360 insert_into_complex (graph, lhs.var, c);
2362 else if (rhs.type == DEREF)
2364 if (!(get_varinfo (lhs.var)->is_special_var))
2365 insert_into_complex (graph, rhs.var, c);
2367 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2368 && (lhs.offset != 0 || rhs.offset != 0))
2370 insert_into_complex (graph, rhs.var, c);
2377 /* Optimize and rewrite complex constraints while performing
2378 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2379 result of perform_variable_substitution. */
2382 rewrite_constraints (constraint_graph_t graph,
2383 struct scc_info *si)
2389 for (j = 0; j < graph->size; j++)
2390 gcc_assert (find (j) == j);
2392 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2394 struct constraint_expr lhs = c->lhs;
2395 struct constraint_expr rhs = c->rhs;
2396 unsigned int lhsvar = find (lhs.var);
2397 unsigned int rhsvar = find (rhs.var);
2398 unsigned int lhsnode, rhsnode;
2399 unsigned int lhslabel, rhslabel;
2401 lhsnode = si->node_mapping[lhsvar];
2402 rhsnode = si->node_mapping[rhsvar];
2403 lhslabel = graph->pointer_label[lhsnode];
2404 rhslabel = graph->pointer_label[rhsnode];
2406 /* See if it is really a non-pointer variable, and if so, ignore
2410 if (dump_file && (dump_flags & TDF_DETAILS))
2413 fprintf (dump_file, "%s is a non-pointer variable,"
2414 "ignoring constraint:",
2415 get_varinfo (lhs.var)->name);
2416 dump_constraint (dump_file, c);
2417 fprintf (dump_file, "\n");
2419 VEC_replace (constraint_t, constraints, i, NULL);
2425 if (dump_file && (dump_flags & TDF_DETAILS))
2428 fprintf (dump_file, "%s is a non-pointer variable,"
2429 "ignoring constraint:",
2430 get_varinfo (rhs.var)->name);
2431 dump_constraint (dump_file, c);
2432 fprintf (dump_file, "\n");
2434 VEC_replace (constraint_t, constraints, i, NULL);
2438 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2439 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2440 c->lhs.var = lhsvar;
2441 c->rhs.var = rhsvar;
2446 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2447 part of an SCC, false otherwise. */
2450 eliminate_indirect_cycles (unsigned int node)
2452 if (graph->indirect_cycles[node] != -1
2453 && !bitmap_empty_p (get_varinfo (node)->solution))
2456 VEC(unsigned,heap) *queue = NULL;
2458 unsigned int to = find (graph->indirect_cycles[node]);
2461 /* We can't touch the solution set and call unify_nodes
2462 at the same time, because unify_nodes is going to do
2463 bitmap unions into it. */
2465 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2467 if (find (i) == i && i != to)
2470 VEC_safe_push (unsigned, heap, queue, i);
2475 VEC_iterate (unsigned, queue, queuepos, i);
2478 unify_nodes (graph, to, i, true);
2480 VEC_free (unsigned, heap, queue);
2486 /* Solve the constraint graph GRAPH using our worklist solver.
2487 This is based on the PW* family of solvers from the "Efficient Field
2488 Sensitive Pointer Analysis for C" paper.
2489 It works by iterating over all the graph nodes, processing the complex
2490 constraints and propagating the copy constraints, until everything stops
2491 changed. This corresponds to steps 6-8 in the solving list given above. */
2494 solve_graph (constraint_graph_t graph)
2496 unsigned int size = graph->size;
2500 changed = BITMAP_ALLOC (NULL);
2502 /* Mark all initial non-collapsed nodes as changed. */
2503 for (i = 0; i < size; i++)
2505 varinfo_t ivi = get_varinfo (i);
2506 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2507 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2508 || VEC_length (constraint_t, graph->complex[i]) > 0))
2509 bitmap_set_bit (changed, i);
2512 /* Allocate a bitmap to be used to store the changed bits. */
2513 pts = BITMAP_ALLOC (&pta_obstack);
2515 while (!bitmap_empty_p (changed))
2518 struct topo_info *ti = init_topo_info ();
2521 bitmap_obstack_initialize (&iteration_obstack);
2523 compute_topo_order (graph, ti);
2525 while (VEC_length (unsigned, ti->topo_order) != 0)
2528 i = VEC_pop (unsigned, ti->topo_order);
2530 /* If this variable is not a representative, skip it. */
2534 /* In certain indirect cycle cases, we may merge this
2535 variable to another. */
2536 if (eliminate_indirect_cycles (i) && find (i) != i)
2539 /* If the node has changed, we need to process the
2540 complex constraints and outgoing edges again. */
2541 if (bitmap_clear_bit (changed, i))
2546 VEC(constraint_t,heap) *complex = graph->complex[i];
2547 bool solution_empty;
2549 /* Compute the changed set of solution bits. */
2550 bitmap_and_compl (pts, get_varinfo (i)->solution,
2551 get_varinfo (i)->oldsolution);
2553 if (bitmap_empty_p (pts))
2556 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2558 solution = get_varinfo (i)->solution;
2559 solution_empty = bitmap_empty_p (solution);
2561 /* Process the complex constraints */
2562 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2564 /* XXX: This is going to unsort the constraints in
2565 some cases, which will occasionally add duplicate
2566 constraints during unification. This does not
2567 affect correctness. */
2568 c->lhs.var = find (c->lhs.var);
2569 c->rhs.var = find (c->rhs.var);
2571 /* The only complex constraint that can change our
2572 solution to non-empty, given an empty solution,
2573 is a constraint where the lhs side is receiving
2574 some set from elsewhere. */
2575 if (!solution_empty || c->lhs.type != DEREF)
2576 do_complex_constraint (graph, c, pts);
2579 solution_empty = bitmap_empty_p (solution);
2581 if (!solution_empty)
2584 unsigned eff_escaped_id = find (escaped_id);
2586 /* Propagate solution to all successors. */
2587 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2593 unsigned int to = find (j);
2594 tmp = get_varinfo (to)->solution;
2597 /* Don't try to propagate to ourselves. */
2601 /* If we propagate from ESCAPED use ESCAPED as
2603 if (i == eff_escaped_id)
2604 flag = bitmap_set_bit (tmp, escaped_id);
2606 flag = set_union_with_increment (tmp, pts, 0);
2610 get_varinfo (to)->solution = tmp;
2611 bitmap_set_bit (changed, to);
2617 free_topo_info (ti);
2618 bitmap_obstack_release (&iteration_obstack);
2622 BITMAP_FREE (changed);
2623 bitmap_obstack_release (&oldpta_obstack);
2626 /* Map from trees to variable infos. */
2627 static struct pointer_map_t *vi_for_tree;
2630 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2633 insert_vi_for_tree (tree t, varinfo_t vi)
2635 void **slot = pointer_map_insert (vi_for_tree, t);
2637 gcc_assert (*slot == NULL);
2641 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2642 exist in the map, return NULL, otherwise, return the varinfo we found. */
2645 lookup_vi_for_tree (tree t)
2647 void **slot = pointer_map_contains (vi_for_tree, t);
2651 return (varinfo_t) *slot;
2654 /* Return a printable name for DECL */
2657 alias_get_name (tree decl)
2661 int num_printed = 0;
2663 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2664 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2666 res= get_name (decl);
2674 if (TREE_CODE (decl) == SSA_NAME)
2676 num_printed = asprintf (&temp, "%s_%u",
2677 alias_get_name (SSA_NAME_VAR (decl)),
2678 SSA_NAME_VERSION (decl));
2680 else if (DECL_P (decl))
2682 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2684 if (num_printed > 0)
2686 res = ggc_strdup (temp);
2692 /* Find the variable id for tree T in the map.
2693 If T doesn't exist in the map, create an entry for it and return it. */
2696 get_vi_for_tree (tree t)
2698 void **slot = pointer_map_contains (vi_for_tree, t);
2700 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2702 return (varinfo_t) *slot;
2705 /* Get a scalar constraint expression for a new temporary variable. */
2707 static struct constraint_expr
2708 new_scalar_tmp_constraint_exp (const char *name)
2710 struct constraint_expr tmp;
2713 vi = new_var_info (NULL_TREE, name);
2717 vi->is_full_var = 1;
2726 /* Get a constraint expression vector from an SSA_VAR_P node.
2727 If address_p is true, the result will be taken its address of. */
2730 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2732 struct constraint_expr cexpr;
2735 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2736 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2738 /* For parameters, get at the points-to set for the actual parm
2740 if (TREE_CODE (t) == SSA_NAME
2741 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2742 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2743 && SSA_NAME_IS_DEFAULT_DEF (t))
2745 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2749 /* For global variables resort to the alias target. */
2750 if (TREE_CODE (t) == VAR_DECL
2751 && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
2753 struct varpool_node *node = varpool_get_node (t);
2754 if (node && node->alias)
2756 node = varpool_variable_node (node, NULL);
2761 vi = get_vi_for_tree (t);
2763 cexpr.type = SCALAR;
2765 /* If we determine the result is "anything", and we know this is readonly,
2766 say it points to readonly memory instead. */
2767 if (cexpr.var == anything_id && TREE_READONLY (t))
2770 cexpr.type = ADDRESSOF;
2771 cexpr.var = readonly_id;
2774 /* If we are not taking the address of the constraint expr, add all
2775 sub-fiels of the variable as well. */
2777 && !vi->is_full_var)
2779 for (; vi; vi = vi->next)
2782 VEC_safe_push (ce_s, heap, *results, &cexpr);
2787 VEC_safe_push (ce_s, heap, *results, &cexpr);
2790 /* Process constraint T, performing various simplifications and then
2791 adding it to our list of overall constraints. */
2794 process_constraint (constraint_t t)
2796 struct constraint_expr rhs = t->rhs;
2797 struct constraint_expr lhs = t->lhs;
2799 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2800 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2802 /* If we didn't get any useful constraint from the lhs we get
2803 &ANYTHING as fallback from get_constraint_for. Deal with
2804 it here by turning it into *ANYTHING. */
2805 if (lhs.type == ADDRESSOF
2806 && lhs.var == anything_id)
2809 /* ADDRESSOF on the lhs is invalid. */
2810 gcc_assert (lhs.type != ADDRESSOF);
2812 /* We shouldn't add constraints from things that cannot have pointers.
2813 It's not completely trivial to avoid in the callers, so do it here. */
2814 if (rhs.type != ADDRESSOF
2815 && !get_varinfo (rhs.var)->may_have_pointers)
2818 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2819 if (!get_varinfo (lhs.var)->may_have_pointers)
2822 /* This can happen in our IR with things like n->a = *p */
2823 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2825 /* Split into tmp = *rhs, *lhs = tmp */
2826 struct constraint_expr tmplhs;
2827 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2828 process_constraint (new_constraint (tmplhs, rhs));
2829 process_constraint (new_constraint (lhs, tmplhs));
2831 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2833 /* Split into tmp = &rhs, *lhs = tmp */
2834 struct constraint_expr tmplhs;
2835 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2836 process_constraint (new_constraint (tmplhs, rhs));
2837 process_constraint (new_constraint (lhs, tmplhs));
2841 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2842 VEC_safe_push (constraint_t, heap, constraints, t);
2847 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2850 static HOST_WIDE_INT
2851 bitpos_of_field (const tree fdecl)
2853 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2854 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2857 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2858 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2862 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2863 resulting constraint expressions in *RESULTS. */
2866 get_constraint_for_ptr_offset (tree ptr, tree offset,
2867 VEC (ce_s, heap) **results)
2869 struct constraint_expr c;
2871 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2873 /* If we do not do field-sensitive PTA adding offsets to pointers
2874 does not change the points-to solution. */
2875 if (!use_field_sensitive)
2877 get_constraint_for_rhs (ptr, results);
2881 /* If the offset is not a non-negative integer constant that fits
2882 in a HOST_WIDE_INT, we have to fall back to a conservative
2883 solution which includes all sub-fields of all pointed-to
2884 variables of ptr. */
2885 if (offset == NULL_TREE
2886 || !host_integerp (offset, 0))
2887 rhsoffset = UNKNOWN_OFFSET;
2890 /* Make sure the bit-offset also fits. */
2891 rhsunitoffset = TREE_INT_CST_LOW (offset);
2892 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2893 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2894 rhsoffset = UNKNOWN_OFFSET;
2897 get_constraint_for_rhs (ptr, results);
2901 /* As we are eventually appending to the solution do not use
2902 VEC_iterate here. */
2903 n = VEC_length (ce_s, *results);
2904 for (j = 0; j < n; j++)
2907 c = *VEC_index (ce_s, *results, j);
2908 curr = get_varinfo (c.var);
2910 if (c.type == ADDRESSOF
2911 /* If this varinfo represents a full variable just use it. */
2912 && curr->is_full_var)
2914 else if (c.type == ADDRESSOF
2915 /* If we do not know the offset add all subfields. */
2916 && rhsoffset == UNKNOWN_OFFSET)
2918 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2921 struct constraint_expr c2;
2923 c2.type = ADDRESSOF;
2925 if (c2.var != c.var)
2926 VEC_safe_push (ce_s, heap, *results, &c2);
2931 else if (c.type == ADDRESSOF)
2934 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2936 /* Search the sub-field which overlaps with the
2937 pointed-to offset. If the result is outside of the variable
2938 we have to provide a conservative result, as the variable is
2939 still reachable from the resulting pointer (even though it
2940 technically cannot point to anything). The last and first
2941 sub-fields are such conservative results.
2942 ??? If we always had a sub-field for &object + 1 then
2943 we could represent this in a more precise way. */
2945 && curr->offset < offset)
2947 temp = first_or_preceding_vi_for_offset (curr, offset);
2949 /* If the found variable is not exactly at the pointed to
2950 result, we have to include the next variable in the
2951 solution as well. Otherwise two increments by offset / 2
2952 do not result in the same or a conservative superset
2954 if (temp->offset != offset
2955 && temp->next != NULL)
2957 struct constraint_expr c2;
2958 c2.var = temp->next->id;
2959 c2.type = ADDRESSOF;
2961 VEC_safe_push (ce_s, heap, *results, &c2);
2967 c.offset = rhsoffset;
2969 VEC_replace (ce_s, *results, j, &c);
2974 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2975 If address_p is true the result will be taken its address of.
2976 If lhs_p is true then the constraint expression is assumed to be used
2980 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2981 bool address_p, bool lhs_p)
2984 HOST_WIDE_INT bitsize = -1;
2985 HOST_WIDE_INT bitmaxsize = -1;
2986 HOST_WIDE_INT bitpos;
2988 struct constraint_expr *result;
2990 /* Some people like to do cute things like take the address of
2993 while (handled_component_p (forzero)
2994 || INDIRECT_REF_P (forzero)
2995 || TREE_CODE (forzero) == MEM_REF)
2996 forzero = TREE_OPERAND (forzero, 0);
2998 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3000 struct constraint_expr temp;
3003 temp.var = integer_id;
3005 VEC_safe_push (ce_s, heap, *results, &temp);
3009 /* Handle type-punning through unions. If we are extracting a pointer
3010 from a union via a possibly type-punning access that pointer
3011 points to anything, similar to a conversion of an integer to
3017 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3018 u = TREE_OPERAND (u, 0))
3019 if (TREE_CODE (u) == COMPONENT_REF
3020 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3022 struct constraint_expr temp;
3025 temp.var = anything_id;
3026 temp.type = ADDRESSOF;
3027 VEC_safe_push (ce_s, heap, *results, &temp);
3032 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3034 /* Pretend to take the address of the base, we'll take care of
3035 adding the required subset of sub-fields below. */
3036 get_constraint_for_1 (t, results, true, lhs_p);
3037 gcc_assert (VEC_length (ce_s, *results) == 1);
3038 result = VEC_last (ce_s, *results);
3040 if (result->type == SCALAR
3041 && get_varinfo (result->var)->is_full_var)
3042 /* For single-field vars do not bother about the offset. */
3044 else if (result->type == SCALAR)
3046 /* In languages like C, you can access one past the end of an
3047 array. You aren't allowed to dereference it, so we can
3048 ignore this constraint. When we handle pointer subtraction,
3049 we may have to do something cute here. */
3051 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3054 /* It's also not true that the constraint will actually start at the
3055 right offset, it may start in some padding. We only care about
3056 setting the constraint to the first actual field it touches, so
3058 struct constraint_expr cexpr = *result;
3060 VEC_pop (ce_s, *results);
3062 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3064 if (ranges_overlap_p (curr->offset, curr->size,
3065 bitpos, bitmaxsize))
3067 cexpr.var = curr->id;
3068 VEC_safe_push (ce_s, heap, *results, &cexpr);
3073 /* If we are going to take the address of this field then
3074 to be able to compute reachability correctly add at least
3075 the last field of the variable. */
3077 && VEC_length (ce_s, *results) == 0)
3079 curr = get_varinfo (cexpr.var);
3080 while (curr->next != NULL)
3082 cexpr.var = curr->id;
3083 VEC_safe_push (ce_s, heap, *results, &cexpr);
3085 else if (VEC_length (ce_s, *results) == 0)
3086 /* Assert that we found *some* field there. The user couldn't be
3087 accessing *only* padding. */
3088 /* Still the user could access one past the end of an array
3089 embedded in a struct resulting in accessing *only* padding. */
3090 /* Or accessing only padding via type-punning to a type
3091 that has a filed just in padding space. */
3093 cexpr.type = SCALAR;
3094 cexpr.var = anything_id;
3096 VEC_safe_push (ce_s, heap, *results, &cexpr);
3099 else if (bitmaxsize == 0)
3101 if (dump_file && (dump_flags & TDF_DETAILS))
3102 fprintf (dump_file, "Access to zero-sized part of variable,"
3106 if (dump_file && (dump_flags & TDF_DETAILS))
3107 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3109 else if (result->type == DEREF)
3111 /* If we do not know exactly where the access goes say so. Note
3112 that only for non-structure accesses we know that we access
3113 at most one subfiled of any variable. */
3115 || bitsize != bitmaxsize
3116 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3117 || result->offset == UNKNOWN_OFFSET)
3118 result->offset = UNKNOWN_OFFSET;
3120 result->offset += bitpos;
3122 else if (result->type == ADDRESSOF)
3124 /* We can end up here for component references on a
3125 VIEW_CONVERT_EXPR <>(&foobar). */
3126 result->type = SCALAR;
3127 result->var = anything_id;
3135 /* Dereference the constraint expression CONS, and return the result.
3136 DEREF (ADDRESSOF) = SCALAR
3137 DEREF (SCALAR) = DEREF
3138 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3139 This is needed so that we can handle dereferencing DEREF constraints. */
3142 do_deref (VEC (ce_s, heap) **constraints)
3144 struct constraint_expr *c;
3147 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3149 if (c->type == SCALAR)
3151 else if (c->type == ADDRESSOF)
3153 else if (c->type == DEREF)
3155 struct constraint_expr tmplhs;
3156 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3157 process_constraint (new_constraint (tmplhs, *c));
3158 c->var = tmplhs.var;
3165 /* Given a tree T, return the constraint expression for taking the
3169 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3171 struct constraint_expr *c;
3174 get_constraint_for_1 (t, results, true, true);
3176 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3178 if (c->type == DEREF)
3181 c->type = ADDRESSOF;
3185 /* Given a tree T, return the constraint expression for it. */
3188 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3191 struct constraint_expr temp;
3193 /* x = integer is all glommed to a single variable, which doesn't
3194 point to anything by itself. That is, of course, unless it is an
3195 integer constant being treated as a pointer, in which case, we
3196 will return that this is really the addressof anything. This
3197 happens below, since it will fall into the default case. The only
3198 case we know something about an integer treated like a pointer is
3199 when it is the NULL pointer, and then we just say it points to
3202 Do not do that if -fno-delete-null-pointer-checks though, because
3203 in that case *NULL does not fail, so it _should_ alias *anything.
3204 It is not worth adding a new option or renaming the existing one,
3205 since this case is relatively obscure. */
3206 if ((TREE_CODE (t) == INTEGER_CST
3207 && integer_zerop (t))
3208 /* The only valid CONSTRUCTORs in gimple with pointer typed
3209 elements are zero-initializer. But in IPA mode we also
3210 process global initializers, so verify at least. */
3211 || (TREE_CODE (t) == CONSTRUCTOR
3212 && CONSTRUCTOR_NELTS (t) == 0))
3214 if (flag_delete_null_pointer_checks)
3215 temp.var = nothing_id;
3217 temp.var = nonlocal_id;
3218 temp.type = ADDRESSOF;
3220 VEC_safe_push (ce_s, heap, *results, &temp);
3224 /* String constants are read-only. */
3225 if (TREE_CODE (t) == STRING_CST)
3227 temp.var = readonly_id;
3230 VEC_safe_push (ce_s, heap, *results, &temp);
3234 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3236 case tcc_expression:
3238 switch (TREE_CODE (t))
3241 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3249 switch (TREE_CODE (t))
3253 struct constraint_expr cs;
3255 tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
3256 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
3259 /* If we are not taking the address then make sure to process
3260 all subvariables we might access. */
3261 cs = *VEC_last (ce_s, *results);
3263 || cs.type != SCALAR)
3266 vi = get_varinfo (cs.var);
3268 if (!vi->is_full_var
3271 unsigned HOST_WIDE_INT size;
3272 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3273 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3276 for (; curr; curr = curr->next)
3278 if (curr->offset - vi->offset < size)
3281 VEC_safe_push (ce_s, heap, *results, &cs);
3290 case ARRAY_RANGE_REF:
3292 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3294 case VIEW_CONVERT_EXPR:
3295 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3298 /* We are missing handling for TARGET_MEM_REF here. */
3303 case tcc_exceptional:
3305 switch (TREE_CODE (t))
3309 get_constraint_for_ssa_var (t, results, address_p);
3316 VEC (ce_s, heap) *tmp = NULL;
3317 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3319 struct constraint_expr *rhsp;
3321 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3322 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3323 VEC_safe_push (ce_s, heap, *results, rhsp);
3324 VEC_truncate (ce_s, tmp, 0);
3326 VEC_free (ce_s, heap, tmp);
3327 /* We do not know whether the constructor was complete,
3328 so technically we have to add &NOTHING or &ANYTHING
3329 like we do for an empty constructor as well. */
3336 case tcc_declaration:
3338 get_constraint_for_ssa_var (t, results, address_p);
3343 /* We cannot refer to automatic variables through constants. */
3344 temp.type = ADDRESSOF;
3345 temp.var = nonlocal_id;
3347 VEC_safe_push (ce_s, heap, *results, &temp);
3353 /* The default fallback is a constraint from anything. */
3354 temp.type = ADDRESSOF;
3355 temp.var = anything_id;
3357 VEC_safe_push (ce_s, heap, *results, &temp);
3360 /* Given a gimple tree T, return the constraint expression vector for it. */
3363 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3365 gcc_assert (VEC_length (ce_s, *results) == 0);
3367 get_constraint_for_1 (t, results, false, true);
3370 /* Given a gimple tree T, return the constraint expression vector for it
3371 to be used as the rhs of a constraint. */
3374 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3376 gcc_assert (VEC_length (ce_s, *results) == 0);
3378 get_constraint_for_1 (t, results, false, false);
3382 /* Efficiently generates constraints from all entries in *RHSC to all
3383 entries in *LHSC. */
3386 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3388 struct constraint_expr *lhsp, *rhsp;
3391 if (VEC_length (ce_s, lhsc) <= 1
3392 || VEC_length (ce_s, rhsc) <= 1)
3394 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3395 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3396 process_constraint (new_constraint (*lhsp, *rhsp));
3400 struct constraint_expr tmp;
3401 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3402 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3403 process_constraint (new_constraint (tmp, *rhsp));
3404 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3405 process_constraint (new_constraint (*lhsp, tmp));
3409 /* Handle aggregate copies by expanding into copies of the respective
3410 fields of the structures. */
3413 do_structure_copy (tree lhsop, tree rhsop)
3415 struct constraint_expr *lhsp, *rhsp;
3416 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3419 get_constraint_for (lhsop, &lhsc);
3420 get_constraint_for_rhs (rhsop, &rhsc);
3421 lhsp = VEC_index (ce_s, lhsc, 0);
3422 rhsp = VEC_index (ce_s, rhsc, 0);
3423 if (lhsp->type == DEREF
3424 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3425 || rhsp->type == DEREF)
3427 if (lhsp->type == DEREF)
3429 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3430 lhsp->offset = UNKNOWN_OFFSET;
3432 if (rhsp->type == DEREF)
3434 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3435 rhsp->offset = UNKNOWN_OFFSET;
3437 process_all_all_constraints (lhsc, rhsc);
3439 else if (lhsp->type == SCALAR
3440 && (rhsp->type == SCALAR
3441 || rhsp->type == ADDRESSOF))
3443 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3444 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3446 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3447 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3448 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3450 varinfo_t lhsv, rhsv;
3451 rhsp = VEC_index (ce_s, rhsc, k);
3452 lhsv = get_varinfo (lhsp->var);
3453 rhsv = get_varinfo (rhsp->var);
3454 if (lhsv->may_have_pointers
3455 && (lhsv->is_full_var
3456 || rhsv->is_full_var
3457 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3458 rhsv->offset + lhsoffset, rhsv->size)))
3459 process_constraint (new_constraint (*lhsp, *rhsp));
3460 if (!rhsv->is_full_var
3461 && (lhsv->is_full_var
3462 || (lhsv->offset + rhsoffset + lhsv->size
3463 > rhsv->offset + lhsoffset + rhsv->size)))
3466 if (k >= VEC_length (ce_s, rhsc))
3476 VEC_free (ce_s, heap, lhsc);
3477 VEC_free (ce_s, heap, rhsc);
3480 /* Create constraints ID = { rhsc }. */
3483 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3485 struct constraint_expr *c;
3486 struct constraint_expr includes;
3490 includes.offset = 0;
3491 includes.type = SCALAR;
3493 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3494 process_constraint (new_constraint (includes, *c));
3497 /* Create a constraint ID = OP. */
3500 make_constraint_to (unsigned id, tree op)
3502 VEC(ce_s, heap) *rhsc = NULL;
3503 get_constraint_for_rhs (op, &rhsc);
3504 make_constraints_to (id, rhsc);
3505 VEC_free (ce_s, heap, rhsc);
3508 /* Create a constraint ID = &FROM. */
3511 make_constraint_from (varinfo_t vi, int from)
3513 struct constraint_expr lhs, rhs;
3521 rhs.type = ADDRESSOF;
3522 process_constraint (new_constraint (lhs, rhs));
3525 /* Create a constraint ID = FROM. */
3528 make_copy_constraint (varinfo_t vi, int from)
3530 struct constraint_expr lhs, rhs;
3539 process_constraint (new_constraint (lhs, rhs));
3542 /* Make constraints necessary to make OP escape. */
3545 make_escape_constraint (tree op)
3547 make_constraint_to (escaped_id, op);
3550 /* Add constraints to that the solution of VI is transitively closed. */
3553 make_transitive_closure_constraints (varinfo_t vi)
3555 struct constraint_expr lhs, rhs;
3564 process_constraint (new_constraint (lhs, rhs));
3566 /* VAR = VAR + UNKNOWN; */
3572 rhs.offset = UNKNOWN_OFFSET;
3573 process_constraint (new_constraint (lhs, rhs));
3576 /* Temporary storage for fake var decls. */
3577 struct obstack fake_var_decl_obstack;
3579 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
3582 build_fake_var_decl (tree type)
3584 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
3585 memset (decl, 0, sizeof (struct tree_var_decl));
3586 TREE_SET_CODE (decl, VAR_DECL);
3587 TREE_TYPE (decl) = type;
3588 DECL_UID (decl) = allocate_decl_uid ();
3589 SET_DECL_PT_UID (decl, -1);
3590 layout_decl (decl, 0);
3594 /* Create a new artificial heap variable with NAME.
3595 Return the created variable. */
3598 make_heapvar (const char *name)
3603 heapvar = build_fake_var_decl (ptr_type_node);
3604 DECL_EXTERNAL (heapvar) = 1;
3606 vi = new_var_info (heapvar, name);
3607 vi->is_artificial_var = true;
3608 vi->is_heap_var = true;
3609 vi->is_unknown_size_var = true;
3613 vi->is_full_var = true;
3614 insert_vi_for_tree (heapvar, vi);
3619 /* Create a new artificial heap variable with NAME and make a
3620 constraint from it to LHS. Return the created variable. */
3623 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3625 varinfo_t vi = make_heapvar (name);
3626 make_constraint_from (lhs, vi->id);
3631 /* Create a new artificial heap variable with NAME and make a
3632 constraint from it to LHS. Set flags according to a tag used
3633 for tracking restrict pointers. */
3636 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3639 vi = make_constraint_from_heapvar (lhs, name);
3640 vi->is_restrict_var = 1;
3641 vi->is_global_var = 0;
3642 vi->is_special_var = 1;
3643 vi->may_have_pointers = 0;
3646 /* In IPA mode there are varinfos for different aspects of reach
3647 function designator. One for the points-to set of the return
3648 value, one for the variables that are clobbered by the function,
3649 one for its uses and one for each parameter (including a single
3650 glob for remaining variadic arguments). */
3652 enum { fi_clobbers = 1, fi_uses = 2,
3653 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3655 /* Get a constraint for the requested part of a function designator FI
3656 when operating in IPA mode. */
3658 static struct constraint_expr
3659 get_function_part_constraint (varinfo_t fi, unsigned part)
3661 struct constraint_expr c;
3663 gcc_assert (in_ipa_mode);
3665 if (fi->id == anything_id)
3667 /* ??? We probably should have a ANYFN special variable. */
3668 c.var = anything_id;
3672 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3674 varinfo_t ai = first_vi_for_offset (fi, part);
3678 c.var = anything_id;
3692 /* For non-IPA mode, generate constraints necessary for a call on the
3696 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3698 struct constraint_expr rhsc;
3700 bool returns_uses = false;
3702 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3704 tree arg = gimple_call_arg (stmt, i);
3705 int flags = gimple_call_arg_flags (stmt, i);
3707 /* If the argument is not used we can ignore it. */
3708 if (flags & EAF_UNUSED)
3711 /* As we compute ESCAPED context-insensitive we do not gain
3712 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3713 set. The argument would still get clobbered through the
3715 ??? We might get away with less (and more precise) constraints
3716 if using a temporary for transitively closing things. */
3717 if ((flags & EAF_NOCLOBBER)
3718 && (flags & EAF_NOESCAPE))
3720 varinfo_t uses = get_call_use_vi (stmt);
3721 if (!(flags & EAF_DIRECT))
3722 make_transitive_closure_constraints (uses);
3723 make_constraint_to (uses->id, arg);
3724 returns_uses = true;
3726 else if (flags & EAF_NOESCAPE)
3728 varinfo_t uses = get_call_use_vi (stmt);
3729 varinfo_t clobbers = get_call_clobber_vi (stmt);
3730 if (!(flags & EAF_DIRECT))
3732 make_transitive_closure_constraints (uses);
3733 make_transitive_closure_constraints (clobbers);
3735 make_constraint_to (uses->id, arg);
3736 make_constraint_to (clobbers->id, arg);
3737 returns_uses = true;
3740 make_escape_constraint (arg);
3743 /* If we added to the calls uses solution make sure we account for
3744 pointers to it to be returned. */
3747 rhsc.var = get_call_use_vi (stmt)->id;
3750 VEC_safe_push (ce_s, heap, *results, &rhsc);
3753 /* The static chain escapes as well. */
3754 if (gimple_call_chain (stmt))
3755 make_escape_constraint (gimple_call_chain (stmt));
3757 /* And if we applied NRV the address of the return slot escapes as well. */
3758 if (gimple_call_return_slot_opt_p (stmt)
3759 && gimple_call_lhs (stmt) != NULL_TREE
3760 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3762 VEC(ce_s, heap) *tmpc = NULL;
3763 struct constraint_expr lhsc, *c;
3764 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3765 lhsc.var = escaped_id;
3768 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3769 process_constraint (new_constraint (lhsc, *c));
3770 VEC_free(ce_s, heap, tmpc);
3773 /* Regular functions return nonlocal memory. */
3774 rhsc.var = nonlocal_id;
3777 VEC_safe_push (ce_s, heap, *results, &rhsc);
3780 /* For non-IPA mode, generate constraints necessary for a call
3781 that returns a pointer and assigns it to LHS. This simply makes
3782 the LHS point to global and escaped variables. */
3785 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3788 VEC(ce_s, heap) *lhsc = NULL;
3790 get_constraint_for (lhs, &lhsc);
3791 /* If the store is to a global decl make sure to
3792 add proper escape constraints. */
3793 lhs = get_base_address (lhs);
3796 && is_global_var (lhs))
3798 struct constraint_expr tmpc;
3799 tmpc.var = escaped_id;
3802 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3805 /* If the call returns an argument unmodified override the rhs
3807 flags = gimple_call_return_flags (stmt);
3808 if (flags & ERF_RETURNS_ARG
3809 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3813 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3814 get_constraint_for (arg, &rhsc);
3815 process_all_all_constraints (lhsc, rhsc);
3816 VEC_free (ce_s, heap, rhsc);
3818 else if (flags & ERF_NOALIAS)
3821 struct constraint_expr tmpc;
3823 vi = make_heapvar ("HEAP");
3824 /* We delay marking allocated storage global until we know if
3826 DECL_EXTERNAL (vi->decl) = 0;
3827 vi->is_global_var = 0;
3828 /* If this is not a real malloc call assume the memory was
3829 initialized and thus may point to global memory. All
3830 builtin functions with the malloc attribute behave in a sane way. */
3832 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3833 make_constraint_from (vi, nonlocal_id);
3836 tmpc.type = ADDRESSOF;
3837 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3840 process_all_all_constraints (lhsc, rhsc);
3842 VEC_free (ce_s, heap, lhsc);
3845 /* For non-IPA mode, generate constraints necessary for a call of a
3846 const function that returns a pointer in the statement STMT. */
3849 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3851 struct constraint_expr rhsc;
3854 /* Treat nested const functions the same as pure functions as far
3855 as the static chain is concerned. */
3856 if (gimple_call_chain (stmt))
3858 varinfo_t uses = get_call_use_vi (stmt);
3859 make_transitive_closure_constraints (uses);
3860 make_constraint_to (uses->id, gimple_call_chain (stmt));
3861 rhsc.var = uses->id;
3864 VEC_safe_push (ce_s, heap, *results, &rhsc);
3867 /* May return arguments. */
3868 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3870 tree arg = gimple_call_arg (stmt, k);
3871 VEC(ce_s, heap) *argc = NULL;
3873 struct constraint_expr *argp;
3874 get_constraint_for_rhs (arg, &argc);
3875 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3876 VEC_safe_push (ce_s, heap, *results, argp);
3877 VEC_free(ce_s, heap, argc);
3880 /* May return addresses of globals. */
3881 rhsc.var = nonlocal_id;
3883 rhsc.type = ADDRESSOF;
3884 VEC_safe_push (ce_s, heap, *results, &rhsc);
3887 /* For non-IPA mode, generate constraints necessary for a call to a
3888 pure function in statement STMT. */
3891 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3893 struct constraint_expr rhsc;
3895 varinfo_t uses = NULL;
3897 /* Memory reached from pointer arguments is call-used. */
3898 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3900 tree arg = gimple_call_arg (stmt, i);
3903 uses = get_call_use_vi (stmt);
3904 make_transitive_closure_constraints (uses);
3906 make_constraint_to (uses->id, arg);
3909 /* The static chain is used as well. */
3910 if (gimple_call_chain (stmt))
3914 uses = get_call_use_vi (stmt);
3915 make_transitive_closure_constraints (uses);
3917 make_constraint_to (uses->id, gimple_call_chain (stmt));
3920 /* Pure functions may return call-used and nonlocal memory. */
3923 rhsc.var = uses->id;
3926 VEC_safe_push (ce_s, heap, *results, &rhsc);
3928 rhsc.var = nonlocal_id;
3931 VEC_safe_push (ce_s, heap, *results, &rhsc);
3935 /* Return the varinfo for the callee of CALL. */
3938 get_fi_for_callee (gimple call)
3940 tree decl, fn = gimple_call_fn (call);
3942 if (fn && TREE_CODE (fn) == OBJ_TYPE_REF)
3943 fn = OBJ_TYPE_REF_EXPR (fn);
3945 /* If we can directly resolve the function being called, do so.
3946 Otherwise, it must be some sort of indirect expression that
3947 we should still be able to handle. */
3948 decl = gimple_call_addr_fndecl (fn);
3950 return get_vi_for_tree (decl);
3952 /* If the function is anything other than a SSA name pointer we have no
3953 clue and should be getting ANYFN (well, ANYTHING for now). */
3954 if (!fn || TREE_CODE (fn) != SSA_NAME)
3955 return get_varinfo (anything_id);
3957 if ((TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL
3958 || TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL)
3959 && SSA_NAME_IS_DEFAULT_DEF (fn))
3960 fn = SSA_NAME_VAR (fn);
3962 return get_vi_for_tree (fn);
3965 /* Create constraints for the builtin call T. Return true if the call
3966 was handled, otherwise false. */
3969 find_func_aliases_for_builtin_call (gimple t)
3971 tree fndecl = gimple_call_fndecl (t);
3972 VEC(ce_s, heap) *lhsc = NULL;
3973 VEC(ce_s, heap) *rhsc = NULL;
3976 if (fndecl != NULL_TREE
3977 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
3978 /* ??? All builtins that are handled here need to be handled
3979 in the alias-oracle query functions explicitly! */
3980 switch (DECL_FUNCTION_CODE (fndecl))
3982 /* All the following functions return a pointer to the same object
3983 as their first argument points to. The functions do not add
3984 to the ESCAPED solution. The functions make the first argument
3985 pointed to memory point to what the second argument pointed to
3986 memory points to. */
3987 case BUILT_IN_STRCPY:
3988 case BUILT_IN_STRNCPY:
3989 case BUILT_IN_BCOPY:
3990 case BUILT_IN_MEMCPY:
3991 case BUILT_IN_MEMMOVE:
3992 case BUILT_IN_MEMPCPY:
3993 case BUILT_IN_STPCPY:
3994 case BUILT_IN_STPNCPY:
3995 case BUILT_IN_STRCAT:
3996 case BUILT_IN_STRNCAT:
3997 case BUILT_IN_STRCPY_CHK:
3998 case BUILT_IN_STRNCPY_CHK:
3999 case BUILT_IN_MEMCPY_CHK:
4000 case BUILT_IN_MEMMOVE_CHK:
4001 case BUILT_IN_MEMPCPY_CHK:
4002 case BUILT_IN_STPCPY_CHK:
4003 case BUILT_IN_STRCAT_CHK:
4004 case BUILT_IN_STRNCAT_CHK:
4006 tree res = gimple_call_lhs (t);
4007 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4008 == BUILT_IN_BCOPY ? 1 : 0));
4009 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4010 == BUILT_IN_BCOPY ? 0 : 1));
4011 if (res != NULL_TREE)
4013 get_constraint_for (res, &lhsc);
4014 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4015 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4016 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4017 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4019 get_constraint_for (dest, &rhsc);
4020 process_all_all_constraints (lhsc, rhsc);
4021 VEC_free (ce_s, heap, lhsc);
4022 VEC_free (ce_s, heap, rhsc);
4024 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4025 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4028 process_all_all_constraints (lhsc, rhsc);
4029 VEC_free (ce_s, heap, lhsc);
4030 VEC_free (ce_s, heap, rhsc);
4033 case BUILT_IN_MEMSET:
4034 case BUILT_IN_MEMSET_CHK:
4036 tree res = gimple_call_lhs (t);
4037 tree dest = gimple_call_arg (t, 0);
4040 struct constraint_expr ac;
4041 if (res != NULL_TREE)
4043 get_constraint_for (res, &lhsc);
4044 get_constraint_for (dest, &rhsc);
4045 process_all_all_constraints (lhsc, rhsc);
4046 VEC_free (ce_s, heap, lhsc);
4047 VEC_free (ce_s, heap, rhsc);
4049 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4051 if (flag_delete_null_pointer_checks
4052 && integer_zerop (gimple_call_arg (t, 1)))
4054 ac.type = ADDRESSOF;
4055 ac.var = nothing_id;
4060 ac.var = integer_id;
4063 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4064 process_constraint (new_constraint (*lhsp, ac));
4065 VEC_free (ce_s, heap, lhsc);
4068 /* All the following functions do not return pointers, do not
4069 modify the points-to sets of memory reachable from their
4070 arguments and do not add to the ESCAPED solution. */
4071 case BUILT_IN_SINCOS:
4072 case BUILT_IN_SINCOSF:
4073 case BUILT_IN_SINCOSL:
4074 case BUILT_IN_FREXP:
4075 case BUILT_IN_FREXPF:
4076 case BUILT_IN_FREXPL:
4077 case BUILT_IN_GAMMA_R:
4078 case BUILT_IN_GAMMAF_R:
4079 case BUILT_IN_GAMMAL_R:
4080 case BUILT_IN_LGAMMA_R:
4081 case BUILT_IN_LGAMMAF_R:
4082 case BUILT_IN_LGAMMAL_R:
4084 case BUILT_IN_MODFF:
4085 case BUILT_IN_MODFL:
4086 case BUILT_IN_REMQUO:
4087 case BUILT_IN_REMQUOF:
4088 case BUILT_IN_REMQUOL:
4091 /* Trampolines are special - they set up passing the static
4093 case BUILT_IN_INIT_TRAMPOLINE:
4095 tree tramp = gimple_call_arg (t, 0);
4096 tree nfunc = gimple_call_arg (t, 1);
4097 tree frame = gimple_call_arg (t, 2);
4099 struct constraint_expr lhs, *rhsp;
4102 varinfo_t nfi = NULL;
4103 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4104 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4107 lhs = get_function_part_constraint (nfi, fi_static_chain);
4108 get_constraint_for (frame, &rhsc);
4109 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4110 process_constraint (new_constraint (lhs, *rhsp));
4111 VEC_free (ce_s, heap, rhsc);
4113 /* Make the frame point to the function for
4114 the trampoline adjustment call. */
4115 get_constraint_for (tramp, &lhsc);
4117 get_constraint_for (nfunc, &rhsc);
4118 process_all_all_constraints (lhsc, rhsc);
4119 VEC_free (ce_s, heap, rhsc);
4120 VEC_free (ce_s, heap, lhsc);
4125 /* Else fallthru to generic handling which will let
4126 the frame escape. */
4129 case BUILT_IN_ADJUST_TRAMPOLINE:
4131 tree tramp = gimple_call_arg (t, 0);
4132 tree res = gimple_call_lhs (t);
4133 if (in_ipa_mode && res)
4135 get_constraint_for (res, &lhsc);
4136 get_constraint_for (tramp, &rhsc);
4138 process_all_all_constraints (lhsc, rhsc);
4139 VEC_free (ce_s, heap, rhsc);
4140 VEC_free (ce_s, heap, lhsc);
4144 /* Variadic argument handling needs to be handled in IPA
4146 case BUILT_IN_VA_START:
4150 tree valist = gimple_call_arg (t, 0);
4151 struct constraint_expr rhs, *lhsp;
4153 /* The va_list gets access to pointers in variadic
4155 fi = lookup_vi_for_tree (cfun->decl);
4156 gcc_assert (fi != NULL);
4157 get_constraint_for (valist, &lhsc);
4159 rhs = get_function_part_constraint (fi, ~0);
4160 rhs.type = ADDRESSOF;
4161 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4162 process_constraint (new_constraint (*lhsp, rhs));
4163 VEC_free (ce_s, heap, lhsc);
4164 /* va_list is clobbered. */
4165 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4170 /* va_end doesn't have any effect that matters. */
4171 case BUILT_IN_VA_END:
4173 /* Alternate return. Simply give up for now. */
4174 case BUILT_IN_RETURN:
4178 || !(fi = get_vi_for_tree (cfun->decl)))
4179 make_constraint_from (get_varinfo (escaped_id), anything_id);
4180 else if (in_ipa_mode
4183 struct constraint_expr lhs, rhs;
4184 lhs = get_function_part_constraint (fi, fi_result);
4185 rhs.var = anything_id;
4188 process_constraint (new_constraint (lhs, rhs));
4192 /* printf-style functions may have hooks to set pointers to
4193 point to somewhere into the generated string. Leave them
4194 for a later excercise... */
4196 /* Fallthru to general call handling. */;
4202 /* Create constraints for the call T. */
4205 find_func_aliases_for_call (gimple t)
4207 tree fndecl = gimple_call_fndecl (t);
4208 VEC(ce_s, heap) *lhsc = NULL;
4209 VEC(ce_s, heap) *rhsc = NULL;
4212 if (fndecl != NULL_TREE
4213 && DECL_BUILT_IN (fndecl)
4214 && find_func_aliases_for_builtin_call (t))
4217 fi = get_fi_for_callee (t);
4219 || (fndecl && !fi->is_fn_info))
4221 VEC(ce_s, heap) *rhsc = NULL;
4222 int flags = gimple_call_flags (t);
4224 /* Const functions can return their arguments and addresses
4225 of global memory but not of escaped memory. */
4226 if (flags & (ECF_CONST|ECF_NOVOPS))
4228 if (gimple_call_lhs (t))
4229 handle_const_call (t, &rhsc);
4231 /* Pure functions can return addresses in and of memory
4232 reachable from their arguments, but they are not an escape
4233 point for reachable memory of their arguments. */
4234 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4235 handle_pure_call (t, &rhsc);
4237 handle_rhs_call (t, &rhsc);
4238 if (gimple_call_lhs (t))
4239 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4240 VEC_free (ce_s, heap, rhsc);
4247 /* Assign all the passed arguments to the appropriate incoming
4248 parameters of the function. */
4249 for (j = 0; j < gimple_call_num_args (t); j++)
4251 struct constraint_expr lhs ;
4252 struct constraint_expr *rhsp;
4253 tree arg = gimple_call_arg (t, j);
4255 get_constraint_for_rhs (arg, &rhsc);
4256 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4257 while (VEC_length (ce_s, rhsc) != 0)
4259 rhsp = VEC_last (ce_s, rhsc);
4260 process_constraint (new_constraint (lhs, *rhsp));
4261 VEC_pop (ce_s, rhsc);
4265 /* If we are returning a value, assign it to the result. */
4266 lhsop = gimple_call_lhs (t);
4269 struct constraint_expr rhs;
4270 struct constraint_expr *lhsp;
4272 get_constraint_for (lhsop, &lhsc);
4273 rhs = get_function_part_constraint (fi, fi_result);
4275 && DECL_RESULT (fndecl)
4276 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4278 VEC(ce_s, heap) *tem = NULL;
4279 VEC_safe_push (ce_s, heap, tem, &rhs);
4281 rhs = *VEC_index (ce_s, tem, 0);
4282 VEC_free(ce_s, heap, tem);
4284 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4285 process_constraint (new_constraint (*lhsp, rhs));
4288 /* If we pass the result decl by reference, honor that. */
4291 && DECL_RESULT (fndecl)
4292 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4294 struct constraint_expr lhs;
4295 struct constraint_expr *rhsp;
4297 get_constraint_for_address_of (lhsop, &rhsc);
4298 lhs = get_function_part_constraint (fi, fi_result);
4299 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4300 process_constraint (new_constraint (lhs, *rhsp));
4301 VEC_free (ce_s, heap, rhsc);
4304 /* If we use a static chain, pass it along. */
4305 if (gimple_call_chain (t))
4307 struct constraint_expr lhs;
4308 struct constraint_expr *rhsp;
4310 get_constraint_for (gimple_call_chain (t), &rhsc);
4311 lhs = get_function_part_constraint (fi, fi_static_chain);
4312 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4313 process_constraint (new_constraint (lhs, *rhsp));
4318 /* Walk statement T setting up aliasing constraints according to the
4319 references found in T. This function is the main part of the
4320 constraint builder. AI points to auxiliary alias information used
4321 when building alias sets and computing alias grouping heuristics. */
4324 find_func_aliases (gimple origt)
4327 VEC(ce_s, heap) *lhsc = NULL;
4328 VEC(ce_s, heap) *rhsc = NULL;
4329 struct constraint_expr *c;
4332 /* Now build constraints expressions. */
4333 if (gimple_code (t) == GIMPLE_PHI)
4338 /* For a phi node, assign all the arguments to
4340 get_constraint_for (gimple_phi_result (t), &lhsc);
4341 for (i = 0; i < gimple_phi_num_args (t); i++)
4343 tree strippedrhs = PHI_ARG_DEF (t, i);
4345 STRIP_NOPS (strippedrhs);
4346 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4348 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4350 struct constraint_expr *c2;
4351 while (VEC_length (ce_s, rhsc) > 0)
4353 c2 = VEC_last (ce_s, rhsc);
4354 process_constraint (new_constraint (*c, *c2));
4355 VEC_pop (ce_s, rhsc);
4360 /* In IPA mode, we need to generate constraints to pass call
4361 arguments through their calls. There are two cases,
4362 either a GIMPLE_CALL returning a value, or just a plain
4363 GIMPLE_CALL when we are not.
4365 In non-ipa mode, we need to generate constraints for each
4366 pointer passed by address. */
4367 else if (is_gimple_call (t))
4368 find_func_aliases_for_call (t);
4370 /* Otherwise, just a regular assignment statement. Only care about
4371 operations with pointer result, others are dealt with as escape
4372 points if they have pointer operands. */
4373 else if (is_gimple_assign (t))
4375 /* Otherwise, just a regular assignment statement. */
4376 tree lhsop = gimple_assign_lhs (t);
4377 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4379 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4380 do_structure_copy (lhsop, rhsop);
4383 enum tree_code code = gimple_assign_rhs_code (t);
4385 get_constraint_for (lhsop, &lhsc);
4387 if (code == POINTER_PLUS_EXPR)
4388 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4389 gimple_assign_rhs2 (t), &rhsc);
4390 else if (code == BIT_AND_EXPR
4391 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4393 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4394 the pointer. Handle it by offsetting it by UNKNOWN. */
4395 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4398 else if ((CONVERT_EXPR_CODE_P (code)
4399 && !(POINTER_TYPE_P (gimple_expr_type (t))
4400 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4401 || gimple_assign_single_p (t))
4402 get_constraint_for_rhs (rhsop, &rhsc);
4403 else if (truth_value_p (code))
4404 /* Truth value results are not pointer (parts). Or at least
4405 very very unreasonable obfuscation of a part. */
4409 /* All other operations are merges. */
4410 VEC (ce_s, heap) *tmp = NULL;
4411 struct constraint_expr *rhsp;
4413 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4414 for (i = 2; i < gimple_num_ops (t); ++i)
4416 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4417 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4418 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4419 VEC_truncate (ce_s, tmp, 0);
4421 VEC_free (ce_s, heap, tmp);
4423 process_all_all_constraints (lhsc, rhsc);
4425 /* If there is a store to a global variable the rhs escapes. */
4426 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4428 && is_global_var (lhsop)
4430 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4431 make_escape_constraint (rhsop);
4432 /* If this is a conversion of a non-restrict pointer to a
4433 restrict pointer track it with a new heapvar. */
4434 else if (gimple_assign_cast_p (t)
4435 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4436 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4437 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4438 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4439 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4442 /* Handle escapes through return. */
4443 else if (gimple_code (t) == GIMPLE_RETURN
4444 && gimple_return_retval (t) != NULL_TREE)
4448 || !(fi = get_vi_for_tree (cfun->decl)))
4449 make_escape_constraint (gimple_return_retval (t));
4450 else if (in_ipa_mode
4453 struct constraint_expr lhs ;
4454 struct constraint_expr *rhsp;
4457 lhs = get_function_part_constraint (fi, fi_result);
4458 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4459 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4460 process_constraint (new_constraint (lhs, *rhsp));
4463 /* Handle asms conservatively by adding escape constraints to everything. */
4464 else if (gimple_code (t) == GIMPLE_ASM)
4466 unsigned i, noutputs;
4467 const char **oconstraints;
4468 const char *constraint;
4469 bool allows_mem, allows_reg, is_inout;
4471 noutputs = gimple_asm_noutputs (t);
4472 oconstraints = XALLOCAVEC (const char *, noutputs);
4474 for (i = 0; i < noutputs; ++i)
4476 tree link = gimple_asm_output_op (t, i);
4477 tree op = TREE_VALUE (link);
4479 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4480 oconstraints[i] = constraint;
4481 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4482 &allows_reg, &is_inout);
4484 /* A memory constraint makes the address of the operand escape. */
4485 if (!allows_reg && allows_mem)
4486 make_escape_constraint (build_fold_addr_expr (op));
4488 /* The asm may read global memory, so outputs may point to
4489 any global memory. */
4492 VEC(ce_s, heap) *lhsc = NULL;
4493 struct constraint_expr rhsc, *lhsp;
4495 get_constraint_for (op, &lhsc);
4496 rhsc.var = nonlocal_id;
4499 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4500 process_constraint (new_constraint (*lhsp, rhsc));
4501 VEC_free (ce_s, heap, lhsc);
4504 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4506 tree link = gimple_asm_input_op (t, i);
4507 tree op = TREE_VALUE (link);
4509 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4511 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4512 &allows_mem, &allows_reg);
4514 /* A memory constraint makes the address of the operand escape. */
4515 if (!allows_reg && allows_mem)
4516 make_escape_constraint (build_fold_addr_expr (op));
4517 /* Strictly we'd only need the constraint to ESCAPED if
4518 the asm clobbers memory, otherwise using something
4519 along the lines of per-call clobbers/uses would be enough. */
4521 make_escape_constraint (op);
4525 VEC_free (ce_s, heap, rhsc);
4526 VEC_free (ce_s, heap, lhsc);
4530 /* Create a constraint adding to the clobber set of FI the memory
4531 pointed to by PTR. */
4534 process_ipa_clobber (varinfo_t fi, tree ptr)
4536 VEC(ce_s, heap) *ptrc = NULL;
4537 struct constraint_expr *c, lhs;
4539 get_constraint_for_rhs (ptr, &ptrc);
4540 lhs = get_function_part_constraint (fi, fi_clobbers);
4541 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4542 process_constraint (new_constraint (lhs, *c));
4543 VEC_free (ce_s, heap, ptrc);
4546 /* Walk statement T setting up clobber and use constraints according to the
4547 references found in T. This function is a main part of the
4548 IPA constraint builder. */
4551 find_func_clobbers (gimple origt)
4554 VEC(ce_s, heap) *lhsc = NULL;
4555 VEC(ce_s, heap) *rhsc = NULL;
4558 /* Add constraints for clobbered/used in IPA mode.
4559 We are not interested in what automatic variables are clobbered
4560 or used as we only use the information in the caller to which
4561 they do not escape. */
4562 gcc_assert (in_ipa_mode);
4564 /* If the stmt refers to memory in any way it better had a VUSE. */
4565 if (gimple_vuse (t) == NULL_TREE)
4568 /* We'd better have function information for the current function. */
4569 fi = lookup_vi_for_tree (cfun->decl);
4570 gcc_assert (fi != NULL);
4572 /* Account for stores in assignments and calls. */
4573 if (gimple_vdef (t) != NULL_TREE
4574 && gimple_has_lhs (t))
4576 tree lhs = gimple_get_lhs (t);
4578 while (handled_component_p (tem))
4579 tem = TREE_OPERAND (tem, 0);
4581 && !auto_var_in_fn_p (tem, cfun->decl))
4582 || INDIRECT_REF_P (tem)
4583 || (TREE_CODE (tem) == MEM_REF
4584 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4586 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4588 struct constraint_expr lhsc, *rhsp;
4590 lhsc = get_function_part_constraint (fi, fi_clobbers);
4591 get_constraint_for_address_of (lhs, &rhsc);
4592 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4593 process_constraint (new_constraint (lhsc, *rhsp));
4594 VEC_free (ce_s, heap, rhsc);
4598 /* Account for uses in assigments and returns. */
4599 if (gimple_assign_single_p (t)
4600 || (gimple_code (t) == GIMPLE_RETURN
4601 && gimple_return_retval (t) != NULL_TREE))
4603 tree rhs = (gimple_assign_single_p (t)
4604 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4606 while (handled_component_p (tem))
4607 tem = TREE_OPERAND (tem, 0);
4609 && !auto_var_in_fn_p (tem, cfun->decl))
4610 || INDIRECT_REF_P (tem)
4611 || (TREE_CODE (tem) == MEM_REF
4612 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4614 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4616 struct constraint_expr lhs, *rhsp;
4618 lhs = get_function_part_constraint (fi, fi_uses);
4619 get_constraint_for_address_of (rhs, &rhsc);
4620 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4621 process_constraint (new_constraint (lhs, *rhsp));
4622 VEC_free (ce_s, heap, rhsc);
4626 if (is_gimple_call (t))
4628 varinfo_t cfi = NULL;
4629 tree decl = gimple_call_fndecl (t);
4630 struct constraint_expr lhs, rhs;
4633 /* For builtins we do not have separate function info. For those
4634 we do not generate escapes for we have to generate clobbers/uses. */
4636 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4637 switch (DECL_FUNCTION_CODE (decl))
4639 /* The following functions use and clobber memory pointed to
4640 by their arguments. */
4641 case BUILT_IN_STRCPY:
4642 case BUILT_IN_STRNCPY:
4643 case BUILT_IN_BCOPY:
4644 case BUILT_IN_MEMCPY:
4645 case BUILT_IN_MEMMOVE:
4646 case BUILT_IN_MEMPCPY:
4647 case BUILT_IN_STPCPY:
4648 case BUILT_IN_STPNCPY:
4649 case BUILT_IN_STRCAT:
4650 case BUILT_IN_STRNCAT:
4651 case BUILT_IN_STRCPY_CHK:
4652 case BUILT_IN_STRNCPY_CHK:
4653 case BUILT_IN_MEMCPY_CHK:
4654 case BUILT_IN_MEMMOVE_CHK:
4655 case BUILT_IN_MEMPCPY_CHK:
4656 case BUILT_IN_STPCPY_CHK:
4657 case BUILT_IN_STRCAT_CHK:
4658 case BUILT_IN_STRNCAT_CHK:
4660 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4661 == BUILT_IN_BCOPY ? 1 : 0));
4662 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4663 == BUILT_IN_BCOPY ? 0 : 1));
4665 struct constraint_expr *rhsp, *lhsp;
4666 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4667 lhs = get_function_part_constraint (fi, fi_clobbers);
4668 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4669 process_constraint (new_constraint (lhs, *lhsp));
4670 VEC_free (ce_s, heap, lhsc);
4671 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4672 lhs = get_function_part_constraint (fi, fi_uses);
4673 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4674 process_constraint (new_constraint (lhs, *rhsp));
4675 VEC_free (ce_s, heap, rhsc);
4678 /* The following function clobbers memory pointed to by
4680 case BUILT_IN_MEMSET:
4681 case BUILT_IN_MEMSET_CHK:
4683 tree dest = gimple_call_arg (t, 0);
4686 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4687 lhs = get_function_part_constraint (fi, fi_clobbers);
4688 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4689 process_constraint (new_constraint (lhs, *lhsp));
4690 VEC_free (ce_s, heap, lhsc);
4693 /* The following functions clobber their second and third
4695 case BUILT_IN_SINCOS:
4696 case BUILT_IN_SINCOSF:
4697 case BUILT_IN_SINCOSL:
4699 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4700 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4703 /* The following functions clobber their second argument. */
4704 case BUILT_IN_FREXP:
4705 case BUILT_IN_FREXPF:
4706 case BUILT_IN_FREXPL:
4707 case BUILT_IN_LGAMMA_R:
4708 case BUILT_IN_LGAMMAF_R:
4709 case BUILT_IN_LGAMMAL_R:
4710 case BUILT_IN_GAMMA_R:
4711 case BUILT_IN_GAMMAF_R:
4712 case BUILT_IN_GAMMAL_R:
4714 case BUILT_IN_MODFF:
4715 case BUILT_IN_MODFL:
4717 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4720 /* The following functions clobber their third argument. */
4721 case BUILT_IN_REMQUO:
4722 case BUILT_IN_REMQUOF:
4723 case BUILT_IN_REMQUOL:
4725 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4728 /* The following functions neither read nor clobber memory. */
4731 /* Trampolines are of no interest to us. */
4732 case BUILT_IN_INIT_TRAMPOLINE:
4733 case BUILT_IN_ADJUST_TRAMPOLINE:
4735 case BUILT_IN_VA_START:
4736 case BUILT_IN_VA_END:
4738 /* printf-style functions may have hooks to set pointers to
4739 point to somewhere into the generated string. Leave them
4740 for a later excercise... */
4742 /* Fallthru to general call handling. */;
4745 /* Parameters passed by value are used. */
4746 lhs = get_function_part_constraint (fi, fi_uses);
4747 for (i = 0; i < gimple_call_num_args (t); i++)
4749 struct constraint_expr *rhsp;
4750 tree arg = gimple_call_arg (t, i);
4752 if (TREE_CODE (arg) == SSA_NAME
4753 || is_gimple_min_invariant (arg))
4756 get_constraint_for_address_of (arg, &rhsc);
4757 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4758 process_constraint (new_constraint (lhs, *rhsp));
4759 VEC_free (ce_s, heap, rhsc);
4762 /* Build constraints for propagating clobbers/uses along the
4764 cfi = get_fi_for_callee (t);
4765 if (cfi->id == anything_id)
4767 if (gimple_vdef (t))
4768 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4770 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4775 /* For callees without function info (that's external functions),
4776 ESCAPED is clobbered and used. */
4777 if (gimple_call_fndecl (t)
4778 && !cfi->is_fn_info)
4782 if (gimple_vdef (t))
4783 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4785 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4787 /* Also honor the call statement use/clobber info. */
4788 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4789 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4791 if ((vi = lookup_call_use_vi (t)) != NULL)
4792 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4797 /* Otherwise the caller clobbers and uses what the callee does.
4798 ??? This should use a new complex constraint that filters
4799 local variables of the callee. */
4800 if (gimple_vdef (t))
4802 lhs = get_function_part_constraint (fi, fi_clobbers);
4803 rhs = get_function_part_constraint (cfi, fi_clobbers);
4804 process_constraint (new_constraint (lhs, rhs));
4806 lhs = get_function_part_constraint (fi, fi_uses);
4807 rhs = get_function_part_constraint (cfi, fi_uses);
4808 process_constraint (new_constraint (lhs, rhs));
4810 else if (gimple_code (t) == GIMPLE_ASM)
4812 /* ??? Ick. We can do better. */
4813 if (gimple_vdef (t))
4814 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4816 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4820 VEC_free (ce_s, heap, rhsc);
4824 /* Find the first varinfo in the same variable as START that overlaps with
4825 OFFSET. Return NULL if we can't find one. */
4828 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4830 /* If the offset is outside of the variable, bail out. */
4831 if (offset >= start->fullsize)
4834 /* If we cannot reach offset from start, lookup the first field
4835 and start from there. */
4836 if (start->offset > offset)
4837 start = lookup_vi_for_tree (start->decl);
4841 /* We may not find a variable in the field list with the actual
4842 offset when when we have glommed a structure to a variable.
4843 In that case, however, offset should still be within the size
4845 if (offset >= start->offset
4846 && (offset - start->offset) < start->size)
4855 /* Find the first varinfo in the same variable as START that overlaps with
4856 OFFSET. If there is no such varinfo the varinfo directly preceding
4857 OFFSET is returned. */
4860 first_or_preceding_vi_for_offset (varinfo_t start,
4861 unsigned HOST_WIDE_INT offset)
4863 /* If we cannot reach offset from start, lookup the first field
4864 and start from there. */
4865 if (start->offset > offset)
4866 start = lookup_vi_for_tree (start->decl);
4868 /* We may not find a variable in the field list with the actual
4869 offset when when we have glommed a structure to a variable.
4870 In that case, however, offset should still be within the size
4872 If we got beyond the offset we look for return the field
4873 directly preceding offset which may be the last field. */
4875 && offset >= start->offset
4876 && !((offset - start->offset) < start->size))
4877 start = start->next;
4883 /* This structure is used during pushing fields onto the fieldstack
4884 to track the offset of the field, since bitpos_of_field gives it
4885 relative to its immediate containing type, and we want it relative
4886 to the ultimate containing object. */
4890 /* Offset from the base of the base containing object to this field. */
4891 HOST_WIDE_INT offset;
4893 /* Size, in bits, of the field. */
4894 unsigned HOST_WIDE_INT size;
4896 unsigned has_unknown_size : 1;
4898 unsigned must_have_pointers : 1;
4900 unsigned may_have_pointers : 1;
4902 unsigned only_restrict_pointers : 1;
4904 typedef struct fieldoff fieldoff_s;
4906 DEF_VEC_O(fieldoff_s);
4907 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4909 /* qsort comparison function for two fieldoff's PA and PB */
4912 fieldoff_compare (const void *pa, const void *pb)
4914 const fieldoff_s *foa = (const fieldoff_s *)pa;
4915 const fieldoff_s *fob = (const fieldoff_s *)pb;
4916 unsigned HOST_WIDE_INT foasize, fobsize;
4918 if (foa->offset < fob->offset)
4920 else if (foa->offset > fob->offset)
4923 foasize = foa->size;
4924 fobsize = fob->size;
4925 if (foasize < fobsize)
4927 else if (foasize > fobsize)
4932 /* Sort a fieldstack according to the field offset and sizes. */
4934 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4936 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
4939 /* Return true if V is a tree that we can have subvars for.
4940 Normally, this is any aggregate type. Also complex
4941 types which are not gimple registers can have subvars. */
4944 var_can_have_subvars (const_tree v)
4946 /* Volatile variables should never have subvars. */
4947 if (TREE_THIS_VOLATILE (v))
4950 /* Non decls or memory tags can never have subvars. */
4954 /* Aggregates without overlapping fields can have subvars. */
4955 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4961 /* Return true if T is a type that does contain pointers. */
4964 type_must_have_pointers (tree type)
4966 if (POINTER_TYPE_P (type))
4969 if (TREE_CODE (type) == ARRAY_TYPE)
4970 return type_must_have_pointers (TREE_TYPE (type));
4972 /* A function or method can have pointers as arguments, so track
4973 those separately. */
4974 if (TREE_CODE (type) == FUNCTION_TYPE
4975 || TREE_CODE (type) == METHOD_TYPE)
4982 field_must_have_pointers (tree t)
4984 return type_must_have_pointers (TREE_TYPE (t));
4987 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4988 the fields of TYPE onto fieldstack, recording their offsets along
4991 OFFSET is used to keep track of the offset in this entire
4992 structure, rather than just the immediately containing structure.
4993 Returns false if the caller is supposed to handle the field we
4997 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4998 HOST_WIDE_INT offset)
5001 bool empty_p = true;
5003 if (TREE_CODE (type) != RECORD_TYPE)
5006 /* If the vector of fields is growing too big, bail out early.
5007 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5009 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5012 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5013 if (TREE_CODE (field) == FIELD_DECL)
5016 HOST_WIDE_INT foff = bitpos_of_field (field);
5018 if (!var_can_have_subvars (field)
5019 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5020 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5022 else if (!push_fields_onto_fieldstack
5023 (TREE_TYPE (field), fieldstack, offset + foff)
5024 && (DECL_SIZE (field)
5025 && !integer_zerop (DECL_SIZE (field))))
5026 /* Empty structures may have actual size, like in C++. So
5027 see if we didn't push any subfields and the size is
5028 nonzero, push the field onto the stack. */
5033 fieldoff_s *pair = NULL;
5034 bool has_unknown_size = false;
5035 bool must_have_pointers_p;
5037 if (!VEC_empty (fieldoff_s, *fieldstack))
5038 pair = VEC_last (fieldoff_s, *fieldstack);
5040 /* If there isn't anything at offset zero, create sth. */
5042 && offset + foff != 0)
5044 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5046 pair->size = offset + foff;
5047 pair->has_unknown_size = false;
5048 pair->must_have_pointers = false;
5049 pair->may_have_pointers = false;
5050 pair->only_restrict_pointers = false;
5053 if (!DECL_SIZE (field)
5054 || !host_integerp (DECL_SIZE (field), 1))
5055 has_unknown_size = true;
5057 /* If adjacent fields do not contain pointers merge them. */
5058 must_have_pointers_p = field_must_have_pointers (field);
5060 && !has_unknown_size
5061 && !must_have_pointers_p
5062 && !pair->must_have_pointers
5063 && !pair->has_unknown_size
5064 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5066 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5070 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5071 pair->offset = offset + foff;
5072 pair->has_unknown_size = has_unknown_size;
5073 if (!has_unknown_size)
5074 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5077 pair->must_have_pointers = must_have_pointers_p;
5078 pair->may_have_pointers = true;
5079 pair->only_restrict_pointers
5080 = (!has_unknown_size
5081 && POINTER_TYPE_P (TREE_TYPE (field))
5082 && TYPE_RESTRICT (TREE_TYPE (field)));
5092 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5093 if it is a varargs function. */
5096 count_num_arguments (tree decl, bool *is_varargs)
5098 unsigned int num = 0;
5101 /* Capture named arguments for K&R functions. They do not
5102 have a prototype and thus no TYPE_ARG_TYPES. */
5103 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5106 /* Check if the function has variadic arguments. */
5107 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5108 if (TREE_VALUE (t) == void_type_node)
5116 /* Creation function node for DECL, using NAME, and return the index
5117 of the variable we've created for the function. */
5120 create_function_info_for (tree decl, const char *name)
5122 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5123 varinfo_t vi, prev_vi;
5126 bool is_varargs = false;
5127 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5129 /* Create the variable info. */
5131 vi = new_var_info (decl, name);
5134 vi->fullsize = fi_parm_base + num_args;
5136 vi->may_have_pointers = false;
5139 insert_vi_for_tree (vi->decl, vi);
5143 /* Create a variable for things the function clobbers and one for
5144 things the function uses. */
5146 varinfo_t clobbervi, usevi;
5147 const char *newname;
5150 asprintf (&tempname, "%s.clobber", name);
5151 newname = ggc_strdup (tempname);
5154 clobbervi = new_var_info (NULL, newname);
5155 clobbervi->offset = fi_clobbers;
5156 clobbervi->size = 1;
5157 clobbervi->fullsize = vi->fullsize;
5158 clobbervi->is_full_var = true;
5159 clobbervi->is_global_var = false;
5160 gcc_assert (prev_vi->offset < clobbervi->offset);
5161 prev_vi->next = clobbervi;
5162 prev_vi = clobbervi;
5164 asprintf (&tempname, "%s.use", name);
5165 newname = ggc_strdup (tempname);
5168 usevi = new_var_info (NULL, newname);
5169 usevi->offset = fi_uses;
5171 usevi->fullsize = vi->fullsize;
5172 usevi->is_full_var = true;
5173 usevi->is_global_var = false;
5174 gcc_assert (prev_vi->offset < usevi->offset);
5175 prev_vi->next = usevi;
5179 /* And one for the static chain. */
5180 if (fn->static_chain_decl != NULL_TREE)
5183 const char *newname;
5186 asprintf (&tempname, "%s.chain", name);
5187 newname = ggc_strdup (tempname);
5190 chainvi = new_var_info (fn->static_chain_decl, newname);
5191 chainvi->offset = fi_static_chain;
5193 chainvi->fullsize = vi->fullsize;
5194 chainvi->is_full_var = true;
5195 chainvi->is_global_var = false;
5196 gcc_assert (prev_vi->offset < chainvi->offset);
5197 prev_vi->next = chainvi;
5199 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5202 /* Create a variable for the return var. */
5203 if (DECL_RESULT (decl) != NULL
5204 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5207 const char *newname;
5209 tree resultdecl = decl;
5211 if (DECL_RESULT (decl))
5212 resultdecl = DECL_RESULT (decl);
5214 asprintf (&tempname, "%s.result", name);
5215 newname = ggc_strdup (tempname);
5218 resultvi = new_var_info (resultdecl, newname);
5219 resultvi->offset = fi_result;
5221 resultvi->fullsize = vi->fullsize;
5222 resultvi->is_full_var = true;
5223 if (DECL_RESULT (decl))
5224 resultvi->may_have_pointers = true;
5225 gcc_assert (prev_vi->offset < resultvi->offset);
5226 prev_vi->next = resultvi;
5228 if (DECL_RESULT (decl))
5229 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5232 /* Set up variables for each argument. */
5233 arg = DECL_ARGUMENTS (decl);
5234 for (i = 0; i < num_args; i++)
5237 const char *newname;
5239 tree argdecl = decl;
5244 asprintf (&tempname, "%s.arg%d", name, i);
5245 newname = ggc_strdup (tempname);
5248 argvi = new_var_info (argdecl, newname);
5249 argvi->offset = fi_parm_base + i;
5251 argvi->is_full_var = true;
5252 argvi->fullsize = vi->fullsize;
5254 argvi->may_have_pointers = true;
5255 gcc_assert (prev_vi->offset < argvi->offset);
5256 prev_vi->next = argvi;
5260 insert_vi_for_tree (arg, argvi);
5261 arg = DECL_CHAIN (arg);
5265 /* Add one representative for all further args. */
5269 const char *newname;
5273 asprintf (&tempname, "%s.varargs", name);
5274 newname = ggc_strdup (tempname);
5277 /* We need sth that can be pointed to for va_start. */
5278 decl = build_fake_var_decl (ptr_type_node);
5280 argvi = new_var_info (decl, newname);
5281 argvi->offset = fi_parm_base + num_args;
5283 argvi->is_full_var = true;
5284 argvi->is_heap_var = true;
5285 argvi->fullsize = vi->fullsize;
5286 gcc_assert (prev_vi->offset < argvi->offset);
5287 prev_vi->next = argvi;
5295 /* Return true if FIELDSTACK contains fields that overlap.
5296 FIELDSTACK is assumed to be sorted by offset. */
5299 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5301 fieldoff_s *fo = NULL;
5303 HOST_WIDE_INT lastoffset = -1;
5305 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5307 if (fo->offset == lastoffset)
5309 lastoffset = fo->offset;
5314 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5315 This will also create any varinfo structures necessary for fields
5319 create_variable_info_for_1 (tree decl, const char *name)
5321 varinfo_t vi, newvi;
5322 tree decl_type = TREE_TYPE (decl);
5323 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5324 VEC (fieldoff_s,heap) *fieldstack = NULL;
5329 || !host_integerp (declsize, 1))
5331 vi = new_var_info (decl, name);
5335 vi->is_unknown_size_var = true;
5336 vi->is_full_var = true;
5337 vi->may_have_pointers = true;
5341 /* Collect field information. */
5342 if (use_field_sensitive
5343 && var_can_have_subvars (decl)
5344 /* ??? Force us to not use subfields for global initializers
5345 in IPA mode. Else we'd have to parse arbitrary initializers. */
5347 && is_global_var (decl)
5348 && DECL_INITIAL (decl)))
5350 fieldoff_s *fo = NULL;
5351 bool notokay = false;
5354 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5356 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5357 if (fo->has_unknown_size
5364 /* We can't sort them if we have a field with a variable sized type,
5365 which will make notokay = true. In that case, we are going to return
5366 without creating varinfos for the fields anyway, so sorting them is a
5370 sort_fieldstack (fieldstack);
5371 /* Due to some C++ FE issues, like PR 22488, we might end up
5372 what appear to be overlapping fields even though they,
5373 in reality, do not overlap. Until the C++ FE is fixed,
5374 we will simply disable field-sensitivity for these cases. */
5375 notokay = check_for_overlaps (fieldstack);
5379 VEC_free (fieldoff_s, heap, fieldstack);
5382 /* If we didn't end up collecting sub-variables create a full
5383 variable for the decl. */
5384 if (VEC_length (fieldoff_s, fieldstack) <= 1
5385 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5387 vi = new_var_info (decl, name);
5389 vi->may_have_pointers = true;
5390 vi->fullsize = TREE_INT_CST_LOW (declsize);
5391 vi->size = vi->fullsize;
5392 vi->is_full_var = true;
5393 VEC_free (fieldoff_s, heap, fieldstack);
5397 vi = new_var_info (decl, name);
5398 vi->fullsize = TREE_INT_CST_LOW (declsize);
5399 for (i = 0, newvi = vi;
5400 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5401 ++i, newvi = newvi->next)
5403 const char *newname = "NULL";
5408 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5409 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5410 newname = ggc_strdup (tempname);
5413 newvi->name = newname;
5414 newvi->offset = fo->offset;
5415 newvi->size = fo->size;
5416 newvi->fullsize = vi->fullsize;
5417 newvi->may_have_pointers = fo->may_have_pointers;
5418 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5419 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5420 newvi->next = new_var_info (decl, name);
5423 VEC_free (fieldoff_s, heap, fieldstack);
5429 create_variable_info_for (tree decl, const char *name)
5431 varinfo_t vi = create_variable_info_for_1 (decl, name);
5432 unsigned int id = vi->id;
5434 insert_vi_for_tree (decl, vi);
5436 /* Create initial constraints for globals. */
5437 for (; vi; vi = vi->next)
5439 if (!vi->may_have_pointers
5440 || !vi->is_global_var)
5443 /* Mark global restrict qualified pointers. */
5444 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5445 && TYPE_RESTRICT (TREE_TYPE (decl)))
5446 || vi->only_restrict_pointers)
5447 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5449 /* For escaped variables initialize them from nonlocal. */
5451 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5452 make_copy_constraint (vi, nonlocal_id);
5454 /* If this is a global variable with an initializer and we are in
5455 IPA mode generate constraints for it. In non-IPA mode
5456 the initializer from nonlocal is all we need. */
5458 && DECL_INITIAL (decl))
5460 VEC (ce_s, heap) *rhsc = NULL;
5461 struct constraint_expr lhs, *rhsp;
5463 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5467 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5468 process_constraint (new_constraint (lhs, *rhsp));
5469 /* If this is a variable that escapes from the unit
5470 the initializer escapes as well. */
5471 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5473 lhs.var = escaped_id;
5476 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5477 process_constraint (new_constraint (lhs, *rhsp));
5479 VEC_free (ce_s, heap, rhsc);
5486 /* Print out the points-to solution for VAR to FILE. */
5489 dump_solution_for_var (FILE *file, unsigned int var)
5491 varinfo_t vi = get_varinfo (var);
5495 /* Dump the solution for unified vars anyway, this avoids difficulties
5496 in scanning dumps in the testsuite. */
5497 fprintf (file, "%s = { ", vi->name);
5498 vi = get_varinfo (find (var));
5499 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5500 fprintf (file, "%s ", get_varinfo (i)->name);
5501 fprintf (file, "}");
5503 /* But note when the variable was unified. */
5505 fprintf (file, " same as %s", vi->name);
5507 fprintf (file, "\n");
5510 /* Print the points-to solution for VAR to stdout. */
5513 debug_solution_for_var (unsigned int var)
5515 dump_solution_for_var (stdout, var);
5518 /* Create varinfo structures for all of the variables in the
5519 function for intraprocedural mode. */
5522 intra_create_variable_infos (void)
5526 /* For each incoming pointer argument arg, create the constraint ARG
5527 = NONLOCAL or a dummy variable if it is a restrict qualified
5528 passed-by-reference argument. */
5529 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5533 /* For restrict qualified pointers to objects passed by
5534 reference build a real representative for the pointed-to object. */
5535 if (DECL_BY_REFERENCE (t)
5536 && POINTER_TYPE_P (TREE_TYPE (t))
5537 && TYPE_RESTRICT (TREE_TYPE (t)))
5539 struct constraint_expr lhsc, rhsc;
5541 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t)));
5542 DECL_EXTERNAL (heapvar) = 1;
5543 vi = get_varinfo (create_variable_info_for (heapvar, "PARM_NOALIAS"));
5544 lhsc.var = get_vi_for_tree (t)->id;
5548 rhsc.type = ADDRESSOF;
5550 process_constraint (new_constraint (lhsc, rhsc));
5551 vi->is_restrict_var = 1;
5555 for (p = get_vi_for_tree (t); p; p = p->next)
5557 if (p->may_have_pointers)
5558 make_constraint_from (p, nonlocal_id);
5559 if (p->only_restrict_pointers)
5560 make_constraint_from_restrict (p, "PARM_RESTRICT");
5562 if (POINTER_TYPE_P (TREE_TYPE (t))
5563 && TYPE_RESTRICT (TREE_TYPE (t)))
5564 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5567 /* Add a constraint for a result decl that is passed by reference. */
5568 if (DECL_RESULT (cfun->decl)
5569 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5571 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5573 for (p = result_vi; p; p = p->next)
5574 make_constraint_from (p, nonlocal_id);
5577 /* Add a constraint for the incoming static chain parameter. */
5578 if (cfun->static_chain_decl != NULL_TREE)
5580 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5582 for (p = chain_vi; p; p = p->next)
5583 make_constraint_from (p, nonlocal_id);
5587 /* Structure used to put solution bitmaps in a hashtable so they can
5588 be shared among variables with the same points-to set. */
5590 typedef struct shared_bitmap_info
5594 } *shared_bitmap_info_t;
5595 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5597 static htab_t shared_bitmap_table;
5599 /* Hash function for a shared_bitmap_info_t */
5602 shared_bitmap_hash (const void *p)
5604 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5605 return bi->hashcode;
5608 /* Equality function for two shared_bitmap_info_t's. */
5611 shared_bitmap_eq (const void *p1, const void *p2)
5613 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5614 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5615 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5618 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5619 existing instance if there is one, NULL otherwise. */
5622 shared_bitmap_lookup (bitmap pt_vars)
5625 struct shared_bitmap_info sbi;
5627 sbi.pt_vars = pt_vars;
5628 sbi.hashcode = bitmap_hash (pt_vars);
5630 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5631 sbi.hashcode, NO_INSERT);
5635 return ((shared_bitmap_info_t) *slot)->pt_vars;
5639 /* Add a bitmap to the shared bitmap hashtable. */
5642 shared_bitmap_add (bitmap pt_vars)
5645 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5647 sbi->pt_vars = pt_vars;
5648 sbi->hashcode = bitmap_hash (pt_vars);
5650 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5651 sbi->hashcode, INSERT);
5652 gcc_assert (!*slot);
5653 *slot = (void *) sbi;
5657 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5660 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5665 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5667 varinfo_t vi = get_varinfo (i);
5669 /* The only artificial variables that are allowed in a may-alias
5670 set are heap variables. */
5671 if (vi->is_artificial_var && !vi->is_heap_var)
5674 if (TREE_CODE (vi->decl) == VAR_DECL
5675 || TREE_CODE (vi->decl) == PARM_DECL
5676 || TREE_CODE (vi->decl) == RESULT_DECL)
5678 /* If we are in IPA mode we will not recompute points-to
5679 sets after inlining so make sure they stay valid. */
5681 && !DECL_PT_UID_SET_P (vi->decl))
5682 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5684 /* Add the decl to the points-to set. Note that the points-to
5685 set contains global variables. */
5686 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5687 if (vi->is_global_var)
5688 pt->vars_contains_global = true;
5694 /* Compute the points-to solution *PT for the variable VI. */
5697 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5701 bitmap finished_solution;
5705 memset (pt, 0, sizeof (struct pt_solution));
5707 /* This variable may have been collapsed, let's get the real
5709 vi = get_varinfo (find (orig_vi->id));
5711 /* Translate artificial variables into SSA_NAME_PTR_INFO
5713 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5715 varinfo_t vi = get_varinfo (i);
5717 if (vi->is_artificial_var)
5719 if (vi->id == nothing_id)
5721 else if (vi->id == escaped_id)
5724 pt->ipa_escaped = 1;
5728 else if (vi->id == nonlocal_id)
5730 else if (vi->is_heap_var)
5731 /* We represent heapvars in the points-to set properly. */
5733 else if (vi->id == readonly_id)
5736 else if (vi->id == anything_id
5737 || vi->id == integer_id)
5740 if (vi->is_restrict_var)
5741 pt->vars_contains_restrict = true;
5744 /* Instead of doing extra work, simply do not create
5745 elaborate points-to information for pt_anything pointers. */
5747 && (orig_vi->is_artificial_var
5748 || !pt->vars_contains_restrict))
5751 /* Share the final set of variables when possible. */
5752 finished_solution = BITMAP_GGC_ALLOC ();
5753 stats.points_to_sets_created++;
5755 set_uids_in_ptset (finished_solution, vi->solution, pt);
5756 result = shared_bitmap_lookup (finished_solution);
5759 shared_bitmap_add (finished_solution);
5760 pt->vars = finished_solution;
5765 bitmap_clear (finished_solution);
5769 /* Given a pointer variable P, fill in its points-to set. */
5772 find_what_p_points_to (tree p)
5774 struct ptr_info_def *pi;
5778 /* For parameters, get at the points-to set for the actual parm
5780 if (TREE_CODE (p) == SSA_NAME
5781 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5782 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5783 && SSA_NAME_IS_DEFAULT_DEF (p))
5784 lookup_p = SSA_NAME_VAR (p);
5786 vi = lookup_vi_for_tree (lookup_p);
5790 pi = get_ptr_info (p);
5791 find_what_var_points_to (vi, &pi->pt);
5795 /* Query statistics for points-to solutions. */
5798 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5799 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5800 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5801 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5805 dump_pta_stats (FILE *s)
5807 fprintf (s, "\nPTA query stats:\n");
5808 fprintf (s, " pt_solution_includes: "
5809 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5810 HOST_WIDE_INT_PRINT_DEC" queries\n",
5811 pta_stats.pt_solution_includes_no_alias,
5812 pta_stats.pt_solution_includes_no_alias
5813 + pta_stats.pt_solution_includes_may_alias);
5814 fprintf (s, " pt_solutions_intersect: "
5815 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5816 HOST_WIDE_INT_PRINT_DEC" queries\n",
5817 pta_stats.pt_solutions_intersect_no_alias,
5818 pta_stats.pt_solutions_intersect_no_alias
5819 + pta_stats.pt_solutions_intersect_may_alias);
5823 /* Reset the points-to solution *PT to a conservative default
5824 (point to anything). */
5827 pt_solution_reset (struct pt_solution *pt)
5829 memset (pt, 0, sizeof (struct pt_solution));
5830 pt->anything = true;
5833 /* Set the points-to solution *PT to point only to the variables
5834 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5835 global variables and VARS_CONTAINS_RESTRICT specifies whether
5836 it contains restrict tag variables. */
5839 pt_solution_set (struct pt_solution *pt, bitmap vars,
5840 bool vars_contains_global, bool vars_contains_restrict)
5842 memset (pt, 0, sizeof (struct pt_solution));
5844 pt->vars_contains_global = vars_contains_global;
5845 pt->vars_contains_restrict = vars_contains_restrict;
5848 /* Set the points-to solution *PT to point only to the variable VAR. */
5851 pt_solution_set_var (struct pt_solution *pt, tree var)
5853 memset (pt, 0, sizeof (struct pt_solution));
5854 pt->vars = BITMAP_GGC_ALLOC ();
5855 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5856 pt->vars_contains_global = is_global_var (var);
5859 /* Computes the union of the points-to solutions *DEST and *SRC and
5860 stores the result in *DEST. This changes the points-to bitmap
5861 of *DEST and thus may not be used if that might be shared.
5862 The points-to bitmap of *SRC and *DEST will not be shared after
5863 this function if they were not before. */
5866 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5868 dest->anything |= src->anything;
5871 pt_solution_reset (dest);
5875 dest->nonlocal |= src->nonlocal;
5876 dest->escaped |= src->escaped;
5877 dest->ipa_escaped |= src->ipa_escaped;
5878 dest->null |= src->null;
5879 dest->vars_contains_global |= src->vars_contains_global;
5880 dest->vars_contains_restrict |= src->vars_contains_restrict;
5885 dest->vars = BITMAP_GGC_ALLOC ();
5886 bitmap_ior_into (dest->vars, src->vars);
5889 /* Return true if the points-to solution *PT is empty. */
5892 pt_solution_empty_p (struct pt_solution *pt)
5899 && !bitmap_empty_p (pt->vars))
5902 /* If the solution includes ESCAPED, check if that is empty. */
5904 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5907 /* If the solution includes ESCAPED, check if that is empty. */
5909 && !pt_solution_empty_p (&ipa_escaped_pt))
5915 /* Return true if the points-to solution *PT includes global memory. */
5918 pt_solution_includes_global (struct pt_solution *pt)
5922 || pt->vars_contains_global)
5926 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5928 if (pt->ipa_escaped)
5929 return pt_solution_includes_global (&ipa_escaped_pt);
5931 /* ??? This predicate is not correct for the IPA-PTA solution
5932 as we do not properly distinguish between unit escape points
5933 and global variables. */
5934 if (cfun->gimple_df->ipa_pta)
5940 /* Return true if the points-to solution *PT includes the variable
5941 declaration DECL. */
5944 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5950 && is_global_var (decl))
5954 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5957 /* If the solution includes ESCAPED, check it. */
5959 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5962 /* If the solution includes ESCAPED, check it. */
5964 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5971 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5973 bool res = pt_solution_includes_1 (pt, decl);
5975 ++pta_stats.pt_solution_includes_may_alias;
5977 ++pta_stats.pt_solution_includes_no_alias;
5981 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5985 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5987 if (pt1->anything || pt2->anything)
5990 /* If either points to unknown global memory and the other points to
5991 any global memory they alias. */
5994 || pt2->vars_contains_global))
5996 && pt1->vars_contains_global))
5999 /* Check the escaped solution if required. */
6000 if ((pt1->escaped || pt2->escaped)
6001 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6003 /* If both point to escaped memory and that solution
6004 is not empty they alias. */
6005 if (pt1->escaped && pt2->escaped)
6008 /* If either points to escaped memory see if the escaped solution
6009 intersects with the other. */
6011 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6013 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6017 /* Check the escaped solution if required.
6018 ??? Do we need to check the local against the IPA escaped sets? */
6019 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6020 && !pt_solution_empty_p (&ipa_escaped_pt))
6022 /* If both point to escaped memory and that solution
6023 is not empty they alias. */
6024 if (pt1->ipa_escaped && pt2->ipa_escaped)
6027 /* If either points to escaped memory see if the escaped solution
6028 intersects with the other. */
6029 if ((pt1->ipa_escaped
6030 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6031 || (pt2->ipa_escaped
6032 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6036 /* Now both pointers alias if their points-to solution intersects. */
6039 && bitmap_intersect_p (pt1->vars, pt2->vars));
6043 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6045 bool res = pt_solutions_intersect_1 (pt1, pt2);
6047 ++pta_stats.pt_solutions_intersect_may_alias;
6049 ++pta_stats.pt_solutions_intersect_no_alias;
6053 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6054 qualified pointers are possibly based on the same pointer. */
6057 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6058 struct pt_solution *pt2)
6060 /* If we deal with points-to solutions of two restrict qualified
6061 pointers solely rely on the pointed-to variable bitmap intersection.
6062 For two pointers that are based on each other the bitmaps will
6064 if (pt1->vars_contains_restrict
6065 && pt2->vars_contains_restrict)
6067 gcc_assert (pt1->vars && pt2->vars);
6068 return bitmap_intersect_p (pt1->vars, pt2->vars);
6075 /* Dump points-to information to OUTFILE. */
6078 dump_sa_points_to_info (FILE *outfile)
6082 fprintf (outfile, "\nPoints-to sets\n\n");
6084 if (dump_flags & TDF_STATS)
6086 fprintf (outfile, "Stats:\n");
6087 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6088 fprintf (outfile, "Non-pointer vars: %d\n",
6089 stats.nonpointer_vars);
6090 fprintf (outfile, "Statically unified vars: %d\n",
6091 stats.unified_vars_static);
6092 fprintf (outfile, "Dynamically unified vars: %d\n",
6093 stats.unified_vars_dynamic);
6094 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6095 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6096 fprintf (outfile, "Number of implicit edges: %d\n",
6097 stats.num_implicit_edges);
6100 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6102 varinfo_t vi = get_varinfo (i);
6103 if (!vi->may_have_pointers)
6105 dump_solution_for_var (outfile, i);
6110 /* Debug points-to information to stderr. */
6113 debug_sa_points_to_info (void)
6115 dump_sa_points_to_info (stderr);
6119 /* Initialize the always-existing constraint variables for NULL
6120 ANYTHING, READONLY, and INTEGER */
6123 init_base_vars (void)
6125 struct constraint_expr lhs, rhs;
6126 varinfo_t var_anything;
6127 varinfo_t var_nothing;
6128 varinfo_t var_readonly;
6129 varinfo_t var_escaped;
6130 varinfo_t var_nonlocal;
6131 varinfo_t var_storedanything;
6132 varinfo_t var_integer;
6134 /* Create the NULL variable, used to represent that a variable points
6136 var_nothing = new_var_info (NULL_TREE, "NULL");
6137 gcc_assert (var_nothing->id == nothing_id);
6138 var_nothing->is_artificial_var = 1;
6139 var_nothing->offset = 0;
6140 var_nothing->size = ~0;
6141 var_nothing->fullsize = ~0;
6142 var_nothing->is_special_var = 1;
6143 var_nothing->may_have_pointers = 0;
6144 var_nothing->is_global_var = 0;
6146 /* Create the ANYTHING variable, used to represent that a variable
6147 points to some unknown piece of memory. */
6148 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6149 gcc_assert (var_anything->id == anything_id);
6150 var_anything->is_artificial_var = 1;
6151 var_anything->size = ~0;
6152 var_anything->offset = 0;
6153 var_anything->next = NULL;
6154 var_anything->fullsize = ~0;
6155 var_anything->is_special_var = 1;
6157 /* Anything points to anything. This makes deref constraints just
6158 work in the presence of linked list and other p = *p type loops,
6159 by saying that *ANYTHING = ANYTHING. */
6161 lhs.var = anything_id;
6163 rhs.type = ADDRESSOF;
6164 rhs.var = anything_id;
6167 /* This specifically does not use process_constraint because
6168 process_constraint ignores all anything = anything constraints, since all
6169 but this one are redundant. */
6170 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6172 /* Create the READONLY variable, used to represent that a variable
6173 points to readonly memory. */
6174 var_readonly = new_var_info (NULL_TREE, "READONLY");
6175 gcc_assert (var_readonly->id == readonly_id);
6176 var_readonly->is_artificial_var = 1;
6177 var_readonly->offset = 0;
6178 var_readonly->size = ~0;
6179 var_readonly->fullsize = ~0;
6180 var_readonly->next = NULL;
6181 var_readonly->is_special_var = 1;
6183 /* readonly memory points to anything, in order to make deref
6184 easier. In reality, it points to anything the particular
6185 readonly variable can point to, but we don't track this
6188 lhs.var = readonly_id;
6190 rhs.type = ADDRESSOF;
6191 rhs.var = readonly_id; /* FIXME */
6193 process_constraint (new_constraint (lhs, rhs));
6195 /* Create the ESCAPED variable, used to represent the set of escaped
6197 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6198 gcc_assert (var_escaped->id == escaped_id);
6199 var_escaped->is_artificial_var = 1;
6200 var_escaped->offset = 0;
6201 var_escaped->size = ~0;
6202 var_escaped->fullsize = ~0;
6203 var_escaped->is_special_var = 0;
6205 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6207 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6208 gcc_assert (var_nonlocal->id == nonlocal_id);
6209 var_nonlocal->is_artificial_var = 1;
6210 var_nonlocal->offset = 0;
6211 var_nonlocal->size = ~0;
6212 var_nonlocal->fullsize = ~0;
6213 var_nonlocal->is_special_var = 1;
6215 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6217 lhs.var = escaped_id;
6220 rhs.var = escaped_id;
6222 process_constraint (new_constraint (lhs, rhs));
6224 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6225 whole variable escapes. */
6227 lhs.var = escaped_id;
6230 rhs.var = escaped_id;
6231 rhs.offset = UNKNOWN_OFFSET;
6232 process_constraint (new_constraint (lhs, rhs));
6234 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6235 everything pointed to by escaped points to what global memory can
6238 lhs.var = escaped_id;
6241 rhs.var = nonlocal_id;
6243 process_constraint (new_constraint (lhs, rhs));
6245 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6246 global memory may point to global memory and escaped memory. */
6248 lhs.var = nonlocal_id;
6250 rhs.type = ADDRESSOF;
6251 rhs.var = nonlocal_id;
6253 process_constraint (new_constraint (lhs, rhs));
6254 rhs.type = ADDRESSOF;
6255 rhs.var = escaped_id;
6257 process_constraint (new_constraint (lhs, rhs));
6259 /* Create the STOREDANYTHING variable, used to represent the set of
6260 variables stored to *ANYTHING. */
6261 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6262 gcc_assert (var_storedanything->id == storedanything_id);
6263 var_storedanything->is_artificial_var = 1;
6264 var_storedanything->offset = 0;
6265 var_storedanything->size = ~0;
6266 var_storedanything->fullsize = ~0;
6267 var_storedanything->is_special_var = 0;
6269 /* Create the INTEGER variable, used to represent that a variable points
6270 to what an INTEGER "points to". */
6271 var_integer = new_var_info (NULL_TREE, "INTEGER");
6272 gcc_assert (var_integer->id == integer_id);
6273 var_integer->is_artificial_var = 1;
6274 var_integer->size = ~0;
6275 var_integer->fullsize = ~0;
6276 var_integer->offset = 0;
6277 var_integer->next = NULL;
6278 var_integer->is_special_var = 1;
6280 /* INTEGER = ANYTHING, because we don't know where a dereference of
6281 a random integer will point to. */
6283 lhs.var = integer_id;
6285 rhs.type = ADDRESSOF;
6286 rhs.var = anything_id;
6288 process_constraint (new_constraint (lhs, rhs));
6291 /* Initialize things necessary to perform PTA */
6294 init_alias_vars (void)
6296 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6298 bitmap_obstack_initialize (&pta_obstack);
6299 bitmap_obstack_initialize (&oldpta_obstack);
6300 bitmap_obstack_initialize (&predbitmap_obstack);
6302 constraint_pool = create_alloc_pool ("Constraint pool",
6303 sizeof (struct constraint), 30);
6304 variable_info_pool = create_alloc_pool ("Variable info pool",
6305 sizeof (struct variable_info), 30);
6306 constraints = VEC_alloc (constraint_t, heap, 8);
6307 varmap = VEC_alloc (varinfo_t, heap, 8);
6308 vi_for_tree = pointer_map_create ();
6309 call_stmt_vars = pointer_map_create ();
6311 memset (&stats, 0, sizeof (stats));
6312 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6313 shared_bitmap_eq, free);
6316 gcc_obstack_init (&fake_var_decl_obstack);
6319 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6320 predecessor edges. */
6323 remove_preds_and_fake_succs (constraint_graph_t graph)
6327 /* Clear the implicit ref and address nodes from the successor
6329 for (i = 0; i < FIRST_REF_NODE; i++)
6331 if (graph->succs[i])
6332 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6333 FIRST_REF_NODE * 2);
6336 /* Free the successor list for the non-ref nodes. */
6337 for (i = FIRST_REF_NODE; i < graph->size; i++)
6339 if (graph->succs[i])
6340 BITMAP_FREE (graph->succs[i]);
6343 /* Now reallocate the size of the successor list as, and blow away
6344 the predecessor bitmaps. */
6345 graph->size = VEC_length (varinfo_t, varmap);
6346 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6348 free (graph->implicit_preds);
6349 graph->implicit_preds = NULL;
6350 free (graph->preds);
6351 graph->preds = NULL;
6352 bitmap_obstack_release (&predbitmap_obstack);
6355 /* Solve the constraint set. */
6358 solve_constraints (void)
6360 struct scc_info *si;
6364 "\nCollapsing static cycles and doing variable "
6367 init_graph (VEC_length (varinfo_t, varmap) * 2);
6370 fprintf (dump_file, "Building predecessor graph\n");
6371 build_pred_graph ();
6374 fprintf (dump_file, "Detecting pointer and location "
6376 si = perform_var_substitution (graph);
6379 fprintf (dump_file, "Rewriting constraints and unifying "
6381 rewrite_constraints (graph, si);
6383 build_succ_graph ();
6385 free_var_substitution_info (si);
6387 /* Attach complex constraints to graph nodes. */
6388 move_complex_constraints (graph);
6391 fprintf (dump_file, "Uniting pointer but not location equivalent "
6393 unite_pointer_equivalences (graph);
6396 fprintf (dump_file, "Finding indirect cycles\n");
6397 find_indirect_cycles (graph);
6399 /* Implicit nodes and predecessors are no longer necessary at this
6401 remove_preds_and_fake_succs (graph);
6403 if (dump_file && (dump_flags & TDF_GRAPH))
6405 fprintf (dump_file, "\n\n// The constraint graph before solve-graph "
6406 "in dot format:\n");
6407 dump_constraint_graph (dump_file);
6408 fprintf (dump_file, "\n\n");
6412 fprintf (dump_file, "Solving graph\n");
6414 solve_graph (graph);
6416 if (dump_file && (dump_flags & TDF_GRAPH))
6418 fprintf (dump_file, "\n\n// The constraint graph after solve-graph "
6419 "in dot format:\n");
6420 dump_constraint_graph (dump_file);
6421 fprintf (dump_file, "\n\n");
6425 dump_sa_points_to_info (dump_file);
6428 /* Create points-to sets for the current function. See the comments
6429 at the start of the file for an algorithmic overview. */
6432 compute_points_to_sets (void)
6438 timevar_push (TV_TREE_PTA);
6442 intra_create_variable_infos ();
6444 /* Now walk all statements and build the constraint set. */
6447 gimple_stmt_iterator gsi;
6449 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6451 gimple phi = gsi_stmt (gsi);
6453 if (is_gimple_reg (gimple_phi_result (phi)))
6454 find_func_aliases (phi);
6457 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6459 gimple stmt = gsi_stmt (gsi);
6461 find_func_aliases (stmt);
6467 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6468 dump_constraints (dump_file, 0);
6471 /* From the constraints compute the points-to sets. */
6472 solve_constraints ();
6474 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6475 find_what_var_points_to (get_varinfo (escaped_id),
6476 &cfun->gimple_df->escaped);
6478 /* Make sure the ESCAPED solution (which is used as placeholder in
6479 other solutions) does not reference itself. This simplifies
6480 points-to solution queries. */
6481 cfun->gimple_df->escaped.escaped = 0;
6483 /* Mark escaped HEAP variables as global. */
6484 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6486 && !vi->is_restrict_var
6487 && !vi->is_global_var)
6488 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6489 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6491 /* Compute the points-to sets for pointer SSA_NAMEs. */
6492 for (i = 0; i < num_ssa_names; ++i)
6494 tree ptr = ssa_name (i);
6496 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6497 find_what_p_points_to (ptr);
6500 /* Compute the call-used/clobbered sets. */
6503 gimple_stmt_iterator gsi;
6505 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6507 gimple stmt = gsi_stmt (gsi);
6508 struct pt_solution *pt;
6509 if (!is_gimple_call (stmt))
6512 pt = gimple_call_use_set (stmt);
6513 if (gimple_call_flags (stmt) & ECF_CONST)
6514 memset (pt, 0, sizeof (struct pt_solution));
6515 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6517 find_what_var_points_to (vi, pt);
6518 /* Escaped (and thus nonlocal) variables are always
6519 implicitly used by calls. */
6520 /* ??? ESCAPED can be empty even though NONLOCAL
6527 /* If there is nothing special about this call then
6528 we have made everything that is used also escape. */
6529 *pt = cfun->gimple_df->escaped;
6533 pt = gimple_call_clobber_set (stmt);
6534 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6535 memset (pt, 0, sizeof (struct pt_solution));
6536 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6538 find_what_var_points_to (vi, pt);
6539 /* Escaped (and thus nonlocal) variables are always
6540 implicitly clobbered by calls. */
6541 /* ??? ESCAPED can be empty even though NONLOCAL
6548 /* If there is nothing special about this call then
6549 we have made everything that is used also escape. */
6550 *pt = cfun->gimple_df->escaped;
6556 timevar_pop (TV_TREE_PTA);
6560 /* Delete created points-to sets. */
6563 delete_points_to_sets (void)
6567 htab_delete (shared_bitmap_table);
6568 if (dump_file && (dump_flags & TDF_STATS))
6569 fprintf (dump_file, "Points to sets created:%d\n",
6570 stats.points_to_sets_created);
6572 pointer_map_destroy (vi_for_tree);
6573 pointer_map_destroy (call_stmt_vars);
6574 bitmap_obstack_release (&pta_obstack);
6575 VEC_free (constraint_t, heap, constraints);
6577 for (i = 0; i < graph->size; i++)
6578 VEC_free (constraint_t, heap, graph->complex[i]);
6579 free (graph->complex);
6582 free (graph->succs);
6584 free (graph->pe_rep);
6585 free (graph->indirect_cycles);
6588 VEC_free (varinfo_t, heap, varmap);
6589 free_alloc_pool (variable_info_pool);
6590 free_alloc_pool (constraint_pool);
6592 obstack_free (&fake_var_decl_obstack, NULL);
6596 /* Compute points-to information for every SSA_NAME pointer in the
6597 current function and compute the transitive closure of escaped
6598 variables to re-initialize the call-clobber states of local variables. */
6601 compute_may_aliases (void)
6603 if (cfun->gimple_df->ipa_pta)
6607 fprintf (dump_file, "\nNot re-computing points-to information "
6608 "because IPA points-to information is available.\n\n");
6610 /* But still dump what we have remaining it. */
6611 dump_alias_info (dump_file);
6613 if (dump_flags & TDF_DETAILS)
6614 dump_referenced_vars (dump_file);
6620 /* For each pointer P_i, determine the sets of variables that P_i may
6621 point-to. Compute the reachability set of escaped and call-used
6623 compute_points_to_sets ();
6625 /* Debugging dumps. */
6628 dump_alias_info (dump_file);
6630 if (dump_flags & TDF_DETAILS)
6631 dump_referenced_vars (dump_file);
6634 /* Deallocate memory used by aliasing data structures and the internal
6635 points-to solution. */
6636 delete_points_to_sets ();
6638 gcc_assert (!need_ssa_update_p (cfun));
6644 gate_tree_pta (void)
6646 return flag_tree_pta;
6649 /* A dummy pass to cause points-to information to be computed via
6650 TODO_rebuild_alias. */
6652 struct gimple_opt_pass pass_build_alias =
6657 gate_tree_pta, /* gate */
6661 0, /* static_pass_number */
6662 TV_NONE, /* tv_id */
6663 PROP_cfg | PROP_ssa, /* properties_required */
6664 0, /* properties_provided */
6665 0, /* properties_destroyed */
6666 0, /* todo_flags_start */
6667 TODO_rebuild_alias /* todo_flags_finish */
6671 /* A dummy pass to cause points-to information to be computed via
6672 TODO_rebuild_alias. */
6674 struct gimple_opt_pass pass_build_ealias =
6678 "ealias", /* name */
6679 gate_tree_pta, /* gate */
6683 0, /* static_pass_number */
6684 TV_NONE, /* tv_id */
6685 PROP_cfg | PROP_ssa, /* properties_required */
6686 0, /* properties_provided */
6687 0, /* properties_destroyed */
6688 0, /* todo_flags_start */
6689 TODO_rebuild_alias /* todo_flags_finish */
6694 /* Return true if we should execute IPA PTA. */
6700 /* Don't bother doing anything if the program has errors. */
6704 /* IPA PTA solutions for ESCAPED. */
6705 struct pt_solution ipa_escaped_pt
6706 = { true, false, false, false, false, false, false, NULL };
6708 /* Associate node with varinfo DATA. Worker for
6709 cgraph_for_node_and_aliases. */
6711 associate_varinfo_to_alias (struct cgraph_node *node, void *data)
6713 if (node->alias || node->thunk.thunk_p)
6714 insert_vi_for_tree (node->decl, (varinfo_t)data);
6718 /* Execute the driver for IPA PTA. */
6720 ipa_pta_execute (void)
6722 struct cgraph_node *node;
6723 struct varpool_node *var;
6730 /* Build the constraints. */
6731 for (node = cgraph_nodes; node; node = node->next)
6734 /* Nodes without a body are not interesting. Especially do not
6735 visit clones at this point for now - we get duplicate decls
6736 there for inline clones at least. */
6737 if (!cgraph_function_with_gimple_body_p (node)
6741 vi = create_function_info_for (node->decl,
6742 alias_get_name (node->decl));
6743 cgraph_for_node_and_aliases (node, associate_varinfo_to_alias, vi, true);
6746 /* Create constraints for global variables and their initializers. */
6747 for (var = varpool_nodes; var; var = var->next)
6752 get_vi_for_tree (var->decl);
6758 "Generating constraints for global initializers\n\n");
6759 dump_constraints (dump_file, 0);
6760 fprintf (dump_file, "\n");
6762 from = VEC_length (constraint_t, constraints);
6764 for (node = cgraph_nodes; node; node = node->next)
6766 struct function *func;
6770 /* Nodes without a body are not interesting. */
6771 if (!cgraph_function_with_gimple_body_p (node)
6778 "Generating constraints for %s", cgraph_node_name (node));
6779 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6780 fprintf (dump_file, " (%s)",
6781 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6782 fprintf (dump_file, "\n");
6785 func = DECL_STRUCT_FUNCTION (node->decl);
6786 old_func_decl = current_function_decl;
6788 current_function_decl = node->decl;
6790 if (node->local.externally_visible)
6792 /* For externally visible functions use local constraints for
6793 their arguments. For local functions we see all callers
6794 and thus do not need initial constraints for parameters. */
6795 intra_create_variable_infos ();
6797 /* We also need to make function return values escape. Nothing
6798 escapes by returning from main though. */
6799 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6802 fi = lookup_vi_for_tree (node->decl);
6803 rvi = first_vi_for_offset (fi, fi_result);
6804 if (rvi && rvi->offset == fi_result)
6806 struct constraint_expr includes;
6807 struct constraint_expr var;
6808 includes.var = escaped_id;
6809 includes.offset = 0;
6810 includes.type = SCALAR;
6814 process_constraint (new_constraint (includes, var));
6819 /* Build constriants for the function body. */
6820 FOR_EACH_BB_FN (bb, func)
6822 gimple_stmt_iterator gsi;
6824 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6827 gimple phi = gsi_stmt (gsi);
6829 if (is_gimple_reg (gimple_phi_result (phi)))
6830 find_func_aliases (phi);
6833 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6835 gimple stmt = gsi_stmt (gsi);
6837 find_func_aliases (stmt);
6838 find_func_clobbers (stmt);
6842 current_function_decl = old_func_decl;
6847 fprintf (dump_file, "\n");
6848 dump_constraints (dump_file, from);
6849 fprintf (dump_file, "\n");
6851 from = VEC_length (constraint_t, constraints);
6854 /* From the constraints compute the points-to sets. */
6855 solve_constraints ();
6857 /* Compute the global points-to sets for ESCAPED.
6858 ??? Note that the computed escape set is not correct
6859 for the whole unit as we fail to consider graph edges to
6860 externally visible functions. */
6861 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6863 /* Make sure the ESCAPED solution (which is used as placeholder in
6864 other solutions) does not reference itself. This simplifies
6865 points-to solution queries. */
6866 ipa_escaped_pt.ipa_escaped = 0;
6868 /* Assign the points-to sets to the SSA names in the unit. */
6869 for (node = cgraph_nodes; node; node = node->next)
6872 struct function *fn;
6876 struct pt_solution uses, clobbers;
6877 struct cgraph_edge *e;
6879 /* Nodes without a body are not interesting. */
6880 if (!cgraph_function_with_gimple_body_p (node)
6884 fn = DECL_STRUCT_FUNCTION (node->decl);
6886 /* Compute the points-to sets for pointer SSA_NAMEs. */
6887 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6890 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6891 find_what_p_points_to (ptr);
6894 /* Compute the call-use and call-clobber sets for all direct calls. */
6895 fi = lookup_vi_for_tree (node->decl);
6896 gcc_assert (fi->is_fn_info);
6897 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6899 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6900 for (e = node->callers; e; e = e->next_caller)
6905 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6906 *gimple_call_use_set (e->call_stmt) = uses;
6909 /* Compute the call-use and call-clobber sets for indirect calls
6910 and calls to external functions. */
6911 FOR_EACH_BB_FN (bb, fn)
6913 gimple_stmt_iterator gsi;
6915 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6917 gimple stmt = gsi_stmt (gsi);
6918 struct pt_solution *pt;
6922 if (!is_gimple_call (stmt))
6925 /* Handle direct calls to external functions. */
6926 decl = gimple_call_fndecl (stmt);
6928 && (!(fi = lookup_vi_for_tree (decl))
6929 || !fi->is_fn_info))
6931 pt = gimple_call_use_set (stmt);
6932 if (gimple_call_flags (stmt) & ECF_CONST)
6933 memset (pt, 0, sizeof (struct pt_solution));
6934 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6936 find_what_var_points_to (vi, pt);
6937 /* Escaped (and thus nonlocal) variables are always
6938 implicitly used by calls. */
6939 /* ??? ESCAPED can be empty even though NONLOCAL
6942 pt->ipa_escaped = 1;
6946 /* If there is nothing special about this call then
6947 we have made everything that is used also escape. */
6948 *pt = ipa_escaped_pt;
6952 pt = gimple_call_clobber_set (stmt);
6953 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6954 memset (pt, 0, sizeof (struct pt_solution));
6955 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6957 find_what_var_points_to (vi, pt);
6958 /* Escaped (and thus nonlocal) variables are always
6959 implicitly clobbered by calls. */
6960 /* ??? ESCAPED can be empty even though NONLOCAL
6963 pt->ipa_escaped = 1;
6967 /* If there is nothing special about this call then
6968 we have made everything that is used also escape. */
6969 *pt = ipa_escaped_pt;
6974 /* Handle indirect calls. */
6976 && (fi = get_fi_for_callee (stmt)))
6978 /* We need to accumulate all clobbers/uses of all possible
6980 fi = get_varinfo (find (fi->id));
6981 /* If we cannot constrain the set of functions we'll end up
6982 calling we end up using/clobbering everything. */
6983 if (bitmap_bit_p (fi->solution, anything_id)
6984 || bitmap_bit_p (fi->solution, nonlocal_id)
6985 || bitmap_bit_p (fi->solution, escaped_id))
6987 pt_solution_reset (gimple_call_clobber_set (stmt));
6988 pt_solution_reset (gimple_call_use_set (stmt));
6994 struct pt_solution *uses, *clobbers;
6996 uses = gimple_call_use_set (stmt);
6997 clobbers = gimple_call_clobber_set (stmt);
6998 memset (uses, 0, sizeof (struct pt_solution));
6999 memset (clobbers, 0, sizeof (struct pt_solution));
7000 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7002 struct pt_solution sol;
7004 vi = get_varinfo (i);
7005 if (!vi->is_fn_info)
7007 /* ??? We could be more precise here? */
7009 uses->ipa_escaped = 1;
7010 clobbers->nonlocal = 1;
7011 clobbers->ipa_escaped = 1;
7015 if (!uses->anything)
7017 find_what_var_points_to
7018 (first_vi_for_offset (vi, fi_uses), &sol);
7019 pt_solution_ior_into (uses, &sol);
7021 if (!clobbers->anything)
7023 find_what_var_points_to
7024 (first_vi_for_offset (vi, fi_clobbers), &sol);
7025 pt_solution_ior_into (clobbers, &sol);
7033 fn->gimple_df->ipa_pta = true;
7036 delete_points_to_sets ();
7043 struct simple_ipa_opt_pass pass_ipa_pta =
7048 gate_ipa_pta, /* gate */
7049 ipa_pta_execute, /* execute */
7052 0, /* static_pass_number */
7053 TV_IPA_PTA, /* tv_id */
7054 0, /* properties_required */
7055 0, /* properties_provided */
7056 0, /* properties_destroyed */
7057 0, /* todo_flags_start */
7058 TODO_update_ssa /* todo_flags_finish */