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 field may contain pointers. */
265 unsigned int may_have_pointers : 1;
267 /* True if this field has only restrict qualified pointers. */
268 unsigned int only_restrict_pointers : 1;
270 /* True if this represents a global variable. */
271 unsigned int is_global_var : 1;
273 /* True if this represents a IPA function info. */
274 unsigned int is_fn_info : 1;
276 /* A link to the variable for the next field in this structure. */
277 struct variable_info *next;
279 /* Offset of this variable, in bits, from the base variable */
280 unsigned HOST_WIDE_INT offset;
282 /* Size of the variable, in bits. */
283 unsigned HOST_WIDE_INT size;
285 /* Full size of the base variable, in bits. */
286 unsigned HOST_WIDE_INT fullsize;
288 /* Name of this variable */
291 /* Tree that this variable is associated with. */
294 /* Points-to set for this variable. */
297 /* Old points-to set for this variable. */
300 typedef struct variable_info *varinfo_t;
302 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
303 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
304 unsigned HOST_WIDE_INT);
305 static varinfo_t lookup_vi_for_tree (tree);
306 static inline bool type_can_have_subvars (const_tree);
308 /* Pool of variable info structures. */
309 static alloc_pool variable_info_pool;
311 DEF_VEC_P(varinfo_t);
313 DEF_VEC_ALLOC_P(varinfo_t, heap);
315 /* Table of variable info structures for constraint variables.
316 Indexed directly by variable info id. */
317 static VEC(varinfo_t,heap) *varmap;
319 /* Return the varmap element N */
321 static inline varinfo_t
322 get_varinfo (unsigned int n)
324 return VEC_index (varinfo_t, varmap, n);
327 /* Static IDs for the special variables. */
328 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
329 escaped_id = 3, nonlocal_id = 4,
330 storedanything_id = 5, integer_id = 6 };
332 /* Return a new variable info structure consisting for a variable
333 named NAME, and using constraint graph node NODE. Append it
334 to the vector of variable info structures. */
337 new_var_info (tree t, const char *name)
339 unsigned index = VEC_length (varinfo_t, varmap);
340 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
345 /* Vars without decl are artificial and do not have sub-variables. */
346 ret->is_artificial_var = (t == NULL_TREE);
347 ret->is_special_var = false;
348 ret->is_unknown_size_var = false;
349 ret->is_full_var = (t == NULL_TREE);
350 ret->is_heap_var = false;
351 ret->may_have_pointers = true;
352 ret->only_restrict_pointers = false;
353 ret->is_global_var = (t == NULL_TREE);
354 ret->is_fn_info = false;
356 ret->is_global_var = (is_global_var (t)
357 /* We have to treat even local register variables
359 || (TREE_CODE (t) == VAR_DECL
360 && DECL_HARD_REGISTER (t)));
361 ret->solution = BITMAP_ALLOC (&pta_obstack);
362 ret->oldsolution = NULL;
367 VEC_safe_push (varinfo_t, heap, varmap, ret);
373 /* A map mapping call statements to per-stmt variables for uses
374 and clobbers specific to the call. */
375 struct pointer_map_t *call_stmt_vars;
377 /* Lookup or create the variable for the call statement CALL. */
380 get_call_vi (gimple call)
385 slot_p = pointer_map_insert (call_stmt_vars, call);
387 return (varinfo_t) *slot_p;
389 vi = new_var_info (NULL_TREE, "CALLUSED");
393 vi->is_full_var = true;
395 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
399 vi2->is_full_var = true;
401 *slot_p = (void *) vi;
405 /* Lookup the variable for the call statement CALL representing
406 the uses. Returns NULL if there is nothing special about this call. */
409 lookup_call_use_vi (gimple call)
413 slot_p = pointer_map_contains (call_stmt_vars, call);
415 return (varinfo_t) *slot_p;
420 /* Lookup the variable for the call statement CALL representing
421 the clobbers. Returns NULL if there is nothing special about this call. */
424 lookup_call_clobber_vi (gimple call)
426 varinfo_t uses = lookup_call_use_vi (call);
433 /* Lookup or create the variable for the call statement CALL representing
437 get_call_use_vi (gimple call)
439 return get_call_vi (call);
442 /* Lookup or create the variable for the call statement CALL representing
445 static varinfo_t ATTRIBUTE_UNUSED
446 get_call_clobber_vi (gimple call)
448 return get_call_vi (call)->next;
452 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
454 /* An expression that appears in a constraint. */
456 struct constraint_expr
458 /* Constraint type. */
459 constraint_expr_type type;
461 /* Variable we are referring to in the constraint. */
464 /* Offset, in bits, of this constraint from the beginning of
465 variables it ends up referring to.
467 IOW, in a deref constraint, we would deref, get the result set,
468 then add OFFSET to each member. */
469 HOST_WIDE_INT offset;
472 /* Use 0x8000... as special unknown offset. */
473 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
475 typedef struct constraint_expr ce_s;
477 DEF_VEC_ALLOC_O(ce_s, heap);
478 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
479 static void get_constraint_for (tree, VEC(ce_s, heap) **);
480 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
481 static void do_deref (VEC (ce_s, heap) **);
483 /* Our set constraints are made up of two constraint expressions, one
486 As described in the introduction, our set constraints each represent an
487 operation between set valued variables.
491 struct constraint_expr lhs;
492 struct constraint_expr rhs;
495 /* List of constraints that we use to build the constraint graph from. */
497 static VEC(constraint_t,heap) *constraints;
498 static alloc_pool constraint_pool;
500 /* The constraint graph is represented as an array of bitmaps
501 containing successor nodes. */
503 struct constraint_graph
505 /* Size of this graph, which may be different than the number of
506 nodes in the variable map. */
509 /* Explicit successors of each node. */
512 /* Implicit predecessors of each node (Used for variable
514 bitmap *implicit_preds;
516 /* Explicit predecessors of each node (Used for variable substitution). */
519 /* Indirect cycle representatives, or -1 if the node has no indirect
521 int *indirect_cycles;
523 /* Representative node for a node. rep[a] == a unless the node has
527 /* Equivalence class representative for a label. This is used for
528 variable substitution. */
531 /* Pointer equivalence label for a node. All nodes with the same
532 pointer equivalence label can be unified together at some point
533 (either during constraint optimization or after the constraint
537 /* Pointer equivalence representative for a label. This is used to
538 handle nodes that are pointer equivalent but not location
539 equivalent. We can unite these once the addressof constraints
540 are transformed into initial points-to sets. */
543 /* Pointer equivalence label for each node, used during variable
545 unsigned int *pointer_label;
547 /* Location equivalence label for each node, used during location
548 equivalence finding. */
549 unsigned int *loc_label;
551 /* Pointed-by set for each node, used during location equivalence
552 finding. This is pointed-by rather than pointed-to, because it
553 is constructed using the predecessor graph. */
556 /* Points to sets for pointer equivalence. This is *not* the actual
557 points-to sets for nodes. */
560 /* Bitmap of nodes where the bit is set if the node is a direct
561 node. Used for variable substitution. */
562 sbitmap direct_nodes;
564 /* Bitmap of nodes where the bit is set if the node is address
565 taken. Used for variable substitution. */
566 bitmap address_taken;
568 /* Vector of complex constraints for each graph node. Complex
569 constraints are those involving dereferences or offsets that are
571 VEC(constraint_t,heap) **complex;
574 static constraint_graph_t graph;
576 /* During variable substitution and the offline version of indirect
577 cycle finding, we create nodes to represent dereferences and
578 address taken constraints. These represent where these start and
580 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
581 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
583 /* Return the representative node for NODE, if NODE has been unioned
585 This function performs path compression along the way to finding
586 the representative. */
589 find (unsigned int node)
591 gcc_assert (node < graph->size);
592 if (graph->rep[node] != node)
593 return graph->rep[node] = find (graph->rep[node]);
597 /* Union the TO and FROM nodes to the TO nodes.
598 Note that at some point in the future, we may want to do
599 union-by-rank, in which case we are going to have to return the
600 node we unified to. */
603 unite (unsigned int to, unsigned int from)
605 gcc_assert (to < graph->size && from < graph->size);
606 if (to != from && graph->rep[from] != to)
608 graph->rep[from] = to;
614 /* Create a new constraint consisting of LHS and RHS expressions. */
617 new_constraint (const struct constraint_expr lhs,
618 const struct constraint_expr rhs)
620 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
626 /* Print out constraint C to FILE. */
629 dump_constraint (FILE *file, constraint_t c)
631 if (c->lhs.type == ADDRESSOF)
633 else if (c->lhs.type == DEREF)
635 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
636 if (c->lhs.offset == UNKNOWN_OFFSET)
637 fprintf (file, " + UNKNOWN");
638 else if (c->lhs.offset != 0)
639 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
640 fprintf (file, " = ");
641 if (c->rhs.type == ADDRESSOF)
643 else if (c->rhs.type == DEREF)
645 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
646 if (c->rhs.offset == UNKNOWN_OFFSET)
647 fprintf (file, " + UNKNOWN");
648 else if (c->rhs.offset != 0)
649 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
653 void debug_constraint (constraint_t);
654 void debug_constraints (void);
655 void debug_constraint_graph (void);
656 void debug_solution_for_var (unsigned int);
657 void debug_sa_points_to_info (void);
659 /* Print out constraint C to stderr. */
662 debug_constraint (constraint_t c)
664 dump_constraint (stderr, c);
665 fprintf (stderr, "\n");
668 /* Print out all constraints to FILE */
671 dump_constraints (FILE *file, int from)
675 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
678 dump_constraint (file, c);
679 fprintf (file, "\n");
683 /* Print out all constraints to stderr. */
686 debug_constraints (void)
688 dump_constraints (stderr, 0);
691 /* Print the constraint graph in dot format. */
694 dump_constraint_graph (FILE *file)
698 /* Only print the graph if it has already been initialized: */
702 /* Prints the header of the dot file: */
703 fprintf (file, "strict digraph {\n");
704 fprintf (file, " node [\n shape = box\n ]\n");
705 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
706 fprintf (file, "\n // List of nodes and complex constraints in "
707 "the constraint graph:\n");
709 /* The next lines print the nodes in the graph together with the
710 complex constraints attached to them. */
711 for (i = 0; i < graph->size; i++)
715 if (i < FIRST_REF_NODE)
716 fprintf (file, "\"%s\"", get_varinfo (i)->name);
718 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
719 if (graph->complex[i])
723 fprintf (file, " [label=\"\\N\\n");
724 for (j = 0; VEC_iterate (constraint_t, graph->complex[i], j, c); ++j)
726 dump_constraint (file, c);
727 fprintf (file, "\\l");
729 fprintf (file, "\"]");
731 fprintf (file, ";\n");
734 /* Go over the edges. */
735 fprintf (file, "\n // Edges in the constraint graph:\n");
736 for (i = 0; i < graph->size; i++)
742 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi)
744 unsigned to = find (j);
747 if (i < FIRST_REF_NODE)
748 fprintf (file, "\"%s\"", get_varinfo (i)->name);
750 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
751 fprintf (file, " -> ");
752 if (to < FIRST_REF_NODE)
753 fprintf (file, "\"%s\"", get_varinfo (to)->name);
755 fprintf (file, "\"*%s\"", get_varinfo (to - FIRST_REF_NODE)->name);
756 fprintf (file, ";\n");
760 /* Prints the tail of the dot file. */
761 fprintf (file, "}\n");
764 /* Print out the constraint graph to stderr. */
767 debug_constraint_graph (void)
769 dump_constraint_graph (stderr);
774 The solver is a simple worklist solver, that works on the following
777 sbitmap changed_nodes = all zeroes;
779 For each node that is not already collapsed:
781 set bit in changed nodes
783 while (changed_count > 0)
785 compute topological ordering for constraint graph
787 find and collapse cycles in the constraint graph (updating
788 changed if necessary)
790 for each node (n) in the graph in topological order:
793 Process each complex constraint associated with the node,
794 updating changed if necessary.
796 For each outgoing edge from n, propagate the solution from n to
797 the destination of the edge, updating changed as necessary.
801 /* Return true if two constraint expressions A and B are equal. */
804 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
806 return a.type == b.type && a.var == b.var && a.offset == b.offset;
809 /* Return true if constraint expression A is less than constraint expression
810 B. This is just arbitrary, but consistent, in order to give them an
814 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
816 if (a.type == b.type)
819 return a.offset < b.offset;
821 return a.var < b.var;
824 return a.type < b.type;
827 /* Return true if constraint A is less than constraint B. This is just
828 arbitrary, but consistent, in order to give them an ordering. */
831 constraint_less (const constraint_t a, const constraint_t b)
833 if (constraint_expr_less (a->lhs, b->lhs))
835 else if (constraint_expr_less (b->lhs, a->lhs))
838 return constraint_expr_less (a->rhs, b->rhs);
841 /* Return true if two constraints A and B are equal. */
844 constraint_equal (struct constraint a, struct constraint b)
846 return constraint_expr_equal (a.lhs, b.lhs)
847 && constraint_expr_equal (a.rhs, b.rhs);
851 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
854 constraint_vec_find (VEC(constraint_t,heap) *vec,
855 struct constraint lookfor)
863 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
864 if (place >= VEC_length (constraint_t, vec))
866 found = VEC_index (constraint_t, vec, place);
867 if (!constraint_equal (*found, lookfor))
872 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
875 constraint_set_union (VEC(constraint_t,heap) **to,
876 VEC(constraint_t,heap) **from)
881 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
883 if (constraint_vec_find (*to, *c) == NULL)
885 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
887 VEC_safe_insert (constraint_t, heap, *to, place, c);
892 /* Expands the solution in SET to all sub-fields of variables included.
893 Union the expanded result into RESULT. */
896 solution_set_expand (bitmap result, bitmap set)
902 /* In a first pass record all variables we need to add all
903 sub-fields off. This avoids quadratic behavior. */
904 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
906 varinfo_t v = get_varinfo (j);
907 if (v->is_artificial_var
910 v = lookup_vi_for_tree (v->decl);
912 vars = BITMAP_ALLOC (NULL);
913 bitmap_set_bit (vars, v->id);
916 /* In the second pass now do the addition to the solution and
917 to speed up solving add it to the delta as well. */
920 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
922 varinfo_t v = get_varinfo (j);
923 for (; v != NULL; v = v->next)
924 bitmap_set_bit (result, v->id);
930 /* Take a solution set SET, add OFFSET to each member of the set, and
931 overwrite SET with the result when done. */
934 solution_set_add (bitmap set, HOST_WIDE_INT offset)
936 bitmap result = BITMAP_ALLOC (&iteration_obstack);
940 /* If the offset is unknown we have to expand the solution to
942 if (offset == UNKNOWN_OFFSET)
944 solution_set_expand (set, set);
948 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
950 varinfo_t vi = get_varinfo (i);
952 /* If this is a variable with just one field just set its bit
954 if (vi->is_artificial_var
955 || vi->is_unknown_size_var
957 bitmap_set_bit (result, i);
960 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
962 /* If the offset makes the pointer point to before the
963 variable use offset zero for the field lookup. */
965 && fieldoffset > vi->offset)
969 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
971 bitmap_set_bit (result, vi->id);
972 /* If the result is not exactly at fieldoffset include the next
973 field as well. See get_constraint_for_ptr_offset for more
975 if (vi->offset != fieldoffset
977 bitmap_set_bit (result, vi->next->id);
981 bitmap_copy (set, result);
982 BITMAP_FREE (result);
985 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
989 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
992 return bitmap_ior_into (to, from);
998 tmp = BITMAP_ALLOC (&iteration_obstack);
999 bitmap_copy (tmp, from);
1000 solution_set_add (tmp, inc);
1001 res = bitmap_ior_into (to, tmp);
1007 /* Insert constraint C into the list of complex constraints for graph
1011 insert_into_complex (constraint_graph_t graph,
1012 unsigned int var, constraint_t c)
1014 VEC (constraint_t, heap) *complex = graph->complex[var];
1015 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1018 /* Only insert constraints that do not already exist. */
1019 if (place >= VEC_length (constraint_t, complex)
1020 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1021 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1025 /* Condense two variable nodes into a single variable node, by moving
1026 all associated info from SRC to TO. */
1029 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1035 gcc_assert (find (from) == to);
1037 /* Move all complex constraints from src node into to node */
1038 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1040 /* In complex constraints for node src, we may have either
1041 a = *src, and *src = a, or an offseted constraint which are
1042 always added to the rhs node's constraints. */
1044 if (c->rhs.type == DEREF)
1046 else if (c->lhs.type == DEREF)
1051 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1052 VEC_free (constraint_t, heap, graph->complex[from]);
1053 graph->complex[from] = NULL;
1057 /* Remove edges involving NODE from GRAPH. */
1060 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1062 if (graph->succs[node])
1063 BITMAP_FREE (graph->succs[node]);
1066 /* Merge GRAPH nodes FROM and TO into node TO. */
1069 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1072 if (graph->indirect_cycles[from] != -1)
1074 /* If we have indirect cycles with the from node, and we have
1075 none on the to node, the to node has indirect cycles from the
1076 from node now that they are unified.
1077 If indirect cycles exist on both, unify the nodes that they
1078 are in a cycle with, since we know they are in a cycle with
1080 if (graph->indirect_cycles[to] == -1)
1081 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1084 /* Merge all the successor edges. */
1085 if (graph->succs[from])
1087 if (!graph->succs[to])
1088 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1089 bitmap_ior_into (graph->succs[to],
1090 graph->succs[from]);
1093 clear_edges_for_node (graph, from);
1097 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1098 it doesn't exist in the graph already. */
1101 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1107 if (!graph->implicit_preds[to])
1108 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1110 if (bitmap_set_bit (graph->implicit_preds[to], from))
1111 stats.num_implicit_edges++;
1114 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1115 it doesn't exist in the graph already.
1116 Return false if the edge already existed, true otherwise. */
1119 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1122 if (!graph->preds[to])
1123 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1124 bitmap_set_bit (graph->preds[to], from);
1127 /* Add a graph edge to GRAPH, going from FROM to TO if
1128 it doesn't exist in the graph already.
1129 Return false if the edge already existed, true otherwise. */
1132 add_graph_edge (constraint_graph_t graph, unsigned int to,
1143 if (!graph->succs[from])
1144 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1145 if (bitmap_set_bit (graph->succs[from], to))
1148 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1156 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1159 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1162 return (graph->succs[dest]
1163 && bitmap_bit_p (graph->succs[dest], src));
1166 /* Initialize the constraint graph structure to contain SIZE nodes. */
1169 init_graph (unsigned int size)
1173 graph = XCNEW (struct constraint_graph);
1175 graph->succs = XCNEWVEC (bitmap, graph->size);
1176 graph->indirect_cycles = XNEWVEC (int, graph->size);
1177 graph->rep = XNEWVEC (unsigned int, graph->size);
1178 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1179 graph->pe = XCNEWVEC (unsigned int, graph->size);
1180 graph->pe_rep = XNEWVEC (int, graph->size);
1182 for (j = 0; j < graph->size; j++)
1185 graph->pe_rep[j] = -1;
1186 graph->indirect_cycles[j] = -1;
1190 /* Build the constraint graph, adding only predecessor edges right now. */
1193 build_pred_graph (void)
1199 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1200 graph->preds = XCNEWVEC (bitmap, graph->size);
1201 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1202 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1203 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1204 graph->points_to = XCNEWVEC (bitmap, graph->size);
1205 graph->eq_rep = XNEWVEC (int, graph->size);
1206 graph->direct_nodes = sbitmap_alloc (graph->size);
1207 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1208 sbitmap_zero (graph->direct_nodes);
1210 for (j = 0; j < FIRST_REF_NODE; j++)
1212 if (!get_varinfo (j)->is_special_var)
1213 SET_BIT (graph->direct_nodes, j);
1216 for (j = 0; j < graph->size; j++)
1217 graph->eq_rep[j] = -1;
1219 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1220 graph->indirect_cycles[j] = -1;
1222 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1224 struct constraint_expr lhs = c->lhs;
1225 struct constraint_expr rhs = c->rhs;
1226 unsigned int lhsvar = lhs.var;
1227 unsigned int rhsvar = rhs.var;
1229 if (lhs.type == DEREF)
1232 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1233 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1235 else if (rhs.type == DEREF)
1238 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1239 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1241 RESET_BIT (graph->direct_nodes, lhsvar);
1243 else if (rhs.type == ADDRESSOF)
1248 if (graph->points_to[lhsvar] == NULL)
1249 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1250 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1252 if (graph->pointed_by[rhsvar] == NULL)
1253 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1254 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1256 /* Implicitly, *x = y */
1257 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1259 /* All related variables are no longer direct nodes. */
1260 RESET_BIT (graph->direct_nodes, rhsvar);
1261 v = get_varinfo (rhsvar);
1262 if (!v->is_full_var)
1264 v = lookup_vi_for_tree (v->decl);
1267 RESET_BIT (graph->direct_nodes, v->id);
1272 bitmap_set_bit (graph->address_taken, rhsvar);
1274 else if (lhsvar > anything_id
1275 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1278 add_pred_graph_edge (graph, lhsvar, rhsvar);
1279 /* Implicitly, *x = *y */
1280 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1281 FIRST_REF_NODE + rhsvar);
1283 else if (lhs.offset != 0 || rhs.offset != 0)
1285 if (rhs.offset != 0)
1286 RESET_BIT (graph->direct_nodes, lhs.var);
1287 else if (lhs.offset != 0)
1288 RESET_BIT (graph->direct_nodes, rhs.var);
1293 /* Build the constraint graph, adding successor edges. */
1296 build_succ_graph (void)
1301 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1303 struct constraint_expr lhs;
1304 struct constraint_expr rhs;
1305 unsigned int lhsvar;
1306 unsigned int rhsvar;
1313 lhsvar = find (lhs.var);
1314 rhsvar = find (rhs.var);
1316 if (lhs.type == DEREF)
1318 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1319 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1321 else if (rhs.type == DEREF)
1323 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1324 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1326 else if (rhs.type == ADDRESSOF)
1329 gcc_assert (find (rhs.var) == rhs.var);
1330 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1332 else if (lhsvar > anything_id
1333 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1335 add_graph_edge (graph, lhsvar, rhsvar);
1339 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1340 receive pointers. */
1341 t = find (storedanything_id);
1342 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1344 if (!TEST_BIT (graph->direct_nodes, i)
1345 && get_varinfo (i)->may_have_pointers)
1346 add_graph_edge (graph, find (i), t);
1349 /* Everything stored to ANYTHING also potentially escapes. */
1350 add_graph_edge (graph, find (escaped_id), t);
1354 /* Changed variables on the last iteration. */
1355 static bitmap changed;
1357 /* Strongly Connected Component visitation info. */
1364 unsigned int *node_mapping;
1366 VEC(unsigned,heap) *scc_stack;
1370 /* Recursive routine to find strongly connected components in GRAPH.
1371 SI is the SCC info to store the information in, and N is the id of current
1372 graph node we are processing.
1374 This is Tarjan's strongly connected component finding algorithm, as
1375 modified by Nuutila to keep only non-root nodes on the stack.
1376 The algorithm can be found in "On finding the strongly connected
1377 connected components in a directed graph" by Esko Nuutila and Eljas
1378 Soisalon-Soininen, in Information Processing Letters volume 49,
1379 number 1, pages 9-14. */
1382 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1386 unsigned int my_dfs;
1388 SET_BIT (si->visited, n);
1389 si->dfs[n] = si->current_index ++;
1390 my_dfs = si->dfs[n];
1392 /* Visit all the successors. */
1393 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1397 if (i > LAST_REF_NODE)
1401 if (TEST_BIT (si->deleted, w))
1404 if (!TEST_BIT (si->visited, w))
1405 scc_visit (graph, si, w);
1407 unsigned int t = find (w);
1408 unsigned int nnode = find (n);
1409 gcc_assert (nnode == n);
1411 if (si->dfs[t] < si->dfs[nnode])
1412 si->dfs[n] = si->dfs[t];
1416 /* See if any components have been identified. */
1417 if (si->dfs[n] == my_dfs)
1419 if (VEC_length (unsigned, si->scc_stack) > 0
1420 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1422 bitmap scc = BITMAP_ALLOC (NULL);
1423 unsigned int lowest_node;
1426 bitmap_set_bit (scc, n);
1428 while (VEC_length (unsigned, si->scc_stack) != 0
1429 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1431 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1433 bitmap_set_bit (scc, w);
1436 lowest_node = bitmap_first_set_bit (scc);
1437 gcc_assert (lowest_node < FIRST_REF_NODE);
1439 /* Collapse the SCC nodes into a single node, and mark the
1441 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1443 if (i < FIRST_REF_NODE)
1445 if (unite (lowest_node, i))
1446 unify_nodes (graph, lowest_node, i, false);
1450 unite (lowest_node, i);
1451 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1455 SET_BIT (si->deleted, n);
1458 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1461 /* Unify node FROM into node TO, updating the changed count if
1462 necessary when UPDATE_CHANGED is true. */
1465 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1466 bool update_changed)
1469 gcc_assert (to != from && find (to) == to);
1470 if (dump_file && (dump_flags & TDF_DETAILS))
1471 fprintf (dump_file, "Unifying %s to %s\n",
1472 get_varinfo (from)->name,
1473 get_varinfo (to)->name);
1476 stats.unified_vars_dynamic++;
1478 stats.unified_vars_static++;
1480 merge_graph_nodes (graph, to, from);
1481 merge_node_constraints (graph, to, from);
1483 /* Mark TO as changed if FROM was changed. If TO was already marked
1484 as changed, decrease the changed count. */
1487 && bitmap_bit_p (changed, from))
1489 bitmap_clear_bit (changed, from);
1490 bitmap_set_bit (changed, to);
1492 if (get_varinfo (from)->solution)
1494 /* If the solution changes because of the merging, we need to mark
1495 the variable as changed. */
1496 if (bitmap_ior_into (get_varinfo (to)->solution,
1497 get_varinfo (from)->solution))
1500 bitmap_set_bit (changed, to);
1503 BITMAP_FREE (get_varinfo (from)->solution);
1504 if (get_varinfo (from)->oldsolution)
1505 BITMAP_FREE (get_varinfo (from)->oldsolution);
1507 if (stats.iterations > 0
1508 && get_varinfo (to)->oldsolution)
1509 BITMAP_FREE (get_varinfo (to)->oldsolution);
1511 if (valid_graph_edge (graph, to, to))
1513 if (graph->succs[to])
1514 bitmap_clear_bit (graph->succs[to], to);
1518 /* Information needed to compute the topological ordering of a graph. */
1522 /* sbitmap of visited nodes. */
1524 /* Array that stores the topological order of the graph, *in
1526 VEC(unsigned,heap) *topo_order;
1530 /* Initialize and return a topological info structure. */
1532 static struct topo_info *
1533 init_topo_info (void)
1535 size_t size = graph->size;
1536 struct topo_info *ti = XNEW (struct topo_info);
1537 ti->visited = sbitmap_alloc (size);
1538 sbitmap_zero (ti->visited);
1539 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1544 /* Free the topological sort info pointed to by TI. */
1547 free_topo_info (struct topo_info *ti)
1549 sbitmap_free (ti->visited);
1550 VEC_free (unsigned, heap, ti->topo_order);
1554 /* Visit the graph in topological order, and store the order in the
1555 topo_info structure. */
1558 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1564 SET_BIT (ti->visited, n);
1566 if (graph->succs[n])
1567 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1569 if (!TEST_BIT (ti->visited, j))
1570 topo_visit (graph, ti, j);
1573 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1576 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1577 starting solution for y. */
1580 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1583 unsigned int lhs = c->lhs.var;
1585 bitmap sol = get_varinfo (lhs)->solution;
1588 HOST_WIDE_INT roffset = c->rhs.offset;
1590 /* Our IL does not allow this. */
1591 gcc_assert (c->lhs.offset == 0);
1593 /* If the solution of Y contains anything it is good enough to transfer
1595 if (bitmap_bit_p (delta, anything_id))
1597 flag |= bitmap_set_bit (sol, anything_id);
1601 /* If we do not know at with offset the rhs is dereferenced compute
1602 the reachability set of DELTA, conservatively assuming it is
1603 dereferenced at all valid offsets. */
1604 if (roffset == UNKNOWN_OFFSET)
1606 solution_set_expand (delta, delta);
1607 /* No further offset processing is necessary. */
1611 /* For each variable j in delta (Sol(y)), add
1612 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1613 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1615 varinfo_t v = get_varinfo (j);
1616 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1620 fieldoffset = v->offset;
1621 else if (roffset != 0)
1622 v = first_vi_for_offset (v, fieldoffset);
1623 /* If the access is outside of the variable we can ignore it. */
1631 /* Adding edges from the special vars is pointless.
1632 They don't have sets that can change. */
1633 if (get_varinfo (t)->is_special_var)
1634 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1635 /* Merging the solution from ESCAPED needlessly increases
1636 the set. Use ESCAPED as representative instead. */
1637 else if (v->id == escaped_id)
1638 flag |= bitmap_set_bit (sol, escaped_id);
1639 else if (v->may_have_pointers
1640 && add_graph_edge (graph, lhs, t))
1641 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1643 /* If the variable is not exactly at the requested offset
1644 we have to include the next one. */
1645 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1650 fieldoffset = v->offset;
1656 /* If the LHS solution changed, mark the var as changed. */
1659 get_varinfo (lhs)->solution = sol;
1660 bitmap_set_bit (changed, lhs);
1664 /* Process a constraint C that represents *(x + off) = y using DELTA
1665 as the starting solution for x. */
1668 do_ds_constraint (constraint_t c, bitmap delta)
1670 unsigned int rhs = c->rhs.var;
1671 bitmap sol = get_varinfo (rhs)->solution;
1674 HOST_WIDE_INT loff = c->lhs.offset;
1675 bool escaped_p = false;
1677 /* Our IL does not allow this. */
1678 gcc_assert (c->rhs.offset == 0);
1680 /* If the solution of y contains ANYTHING simply use the ANYTHING
1681 solution. This avoids needlessly increasing the points-to sets. */
1682 if (bitmap_bit_p (sol, anything_id))
1683 sol = get_varinfo (find (anything_id))->solution;
1685 /* If the solution for x contains ANYTHING we have to merge the
1686 solution of y into all pointer variables which we do via
1688 if (bitmap_bit_p (delta, anything_id))
1690 unsigned t = find (storedanything_id);
1691 if (add_graph_edge (graph, t, rhs))
1693 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1694 bitmap_set_bit (changed, t);
1699 /* If we do not know at with offset the rhs is dereferenced compute
1700 the reachability set of DELTA, conservatively assuming it is
1701 dereferenced at all valid offsets. */
1702 if (loff == UNKNOWN_OFFSET)
1704 solution_set_expand (delta, delta);
1708 /* For each member j of delta (Sol(x)), add an edge from y to j and
1709 union Sol(y) into Sol(j) */
1710 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1712 varinfo_t v = get_varinfo (j);
1714 HOST_WIDE_INT fieldoffset = v->offset + loff;
1717 fieldoffset = v->offset;
1719 v = first_vi_for_offset (v, fieldoffset);
1720 /* If the access is outside of the variable we can ignore it. */
1726 if (v->may_have_pointers)
1728 /* If v is a global variable then this is an escape point. */
1729 if (v->is_global_var
1732 t = find (escaped_id);
1733 if (add_graph_edge (graph, t, rhs)
1734 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1735 bitmap_set_bit (changed, t);
1736 /* Enough to let rhs escape once. */
1740 if (v->is_special_var)
1744 if (add_graph_edge (graph, t, rhs)
1745 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1746 bitmap_set_bit (changed, t);
1749 /* If the variable is not exactly at the requested offset
1750 we have to include the next one. */
1751 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1756 fieldoffset = v->offset;
1762 /* Handle a non-simple (simple meaning requires no iteration),
1763 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1766 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1768 if (c->lhs.type == DEREF)
1770 if (c->rhs.type == ADDRESSOF)
1777 do_ds_constraint (c, delta);
1780 else if (c->rhs.type == DEREF)
1783 if (!(get_varinfo (c->lhs.var)->is_special_var))
1784 do_sd_constraint (graph, c, delta);
1792 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1793 solution = get_varinfo (c->rhs.var)->solution;
1794 tmp = get_varinfo (c->lhs.var)->solution;
1796 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1800 get_varinfo (c->lhs.var)->solution = tmp;
1801 bitmap_set_bit (changed, c->lhs.var);
1806 /* Initialize and return a new SCC info structure. */
1808 static struct scc_info *
1809 init_scc_info (size_t size)
1811 struct scc_info *si = XNEW (struct scc_info);
1814 si->current_index = 0;
1815 si->visited = sbitmap_alloc (size);
1816 sbitmap_zero (si->visited);
1817 si->deleted = sbitmap_alloc (size);
1818 sbitmap_zero (si->deleted);
1819 si->node_mapping = XNEWVEC (unsigned int, size);
1820 si->dfs = XCNEWVEC (unsigned int, size);
1822 for (i = 0; i < size; i++)
1823 si->node_mapping[i] = i;
1825 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1829 /* Free an SCC info structure pointed to by SI */
1832 free_scc_info (struct scc_info *si)
1834 sbitmap_free (si->visited);
1835 sbitmap_free (si->deleted);
1836 free (si->node_mapping);
1838 VEC_free (unsigned, heap, si->scc_stack);
1843 /* Find indirect cycles in GRAPH that occur, using strongly connected
1844 components, and note them in the indirect cycles map.
1846 This technique comes from Ben Hardekopf and Calvin Lin,
1847 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1848 Lines of Code", submitted to PLDI 2007. */
1851 find_indirect_cycles (constraint_graph_t graph)
1854 unsigned int size = graph->size;
1855 struct scc_info *si = init_scc_info (size);
1857 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1858 if (!TEST_BIT (si->visited, i) && find (i) == i)
1859 scc_visit (graph, si, i);
1864 /* Compute a topological ordering for GRAPH, and store the result in the
1865 topo_info structure TI. */
1868 compute_topo_order (constraint_graph_t graph,
1869 struct topo_info *ti)
1872 unsigned int size = graph->size;
1874 for (i = 0; i != size; ++i)
1875 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1876 topo_visit (graph, ti, i);
1879 /* Structure used to for hash value numbering of pointer equivalence
1882 typedef struct equiv_class_label
1885 unsigned int equivalence_class;
1887 } *equiv_class_label_t;
1888 typedef const struct equiv_class_label *const_equiv_class_label_t;
1890 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1892 static htab_t pointer_equiv_class_table;
1894 /* A hashtable for mapping a bitmap of labels->location equivalence
1896 static htab_t location_equiv_class_table;
1898 /* Hash function for a equiv_class_label_t */
1901 equiv_class_label_hash (const void *p)
1903 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1904 return ecl->hashcode;
1907 /* Equality function for two equiv_class_label_t's. */
1910 equiv_class_label_eq (const void *p1, const void *p2)
1912 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1913 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1914 return (eql1->hashcode == eql2->hashcode
1915 && bitmap_equal_p (eql1->labels, eql2->labels));
1918 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1922 equiv_class_lookup (htab_t table, bitmap labels)
1925 struct equiv_class_label ecl;
1927 ecl.labels = labels;
1928 ecl.hashcode = bitmap_hash (labels);
1930 slot = htab_find_slot_with_hash (table, &ecl,
1931 ecl.hashcode, NO_INSERT);
1935 return ((equiv_class_label_t) *slot)->equivalence_class;
1939 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1943 equiv_class_add (htab_t table, unsigned int equivalence_class,
1947 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1949 ecl->labels = labels;
1950 ecl->equivalence_class = equivalence_class;
1951 ecl->hashcode = bitmap_hash (labels);
1953 slot = htab_find_slot_with_hash (table, ecl,
1954 ecl->hashcode, INSERT);
1955 gcc_assert (!*slot);
1956 *slot = (void *) ecl;
1959 /* Perform offline variable substitution.
1961 This is a worst case quadratic time way of identifying variables
1962 that must have equivalent points-to sets, including those caused by
1963 static cycles, and single entry subgraphs, in the constraint graph.
1965 The technique is described in "Exploiting Pointer and Location
1966 Equivalence to Optimize Pointer Analysis. In the 14th International
1967 Static Analysis Symposium (SAS), August 2007." It is known as the
1968 "HU" algorithm, and is equivalent to value numbering the collapsed
1969 constraint graph including evaluating unions.
1971 The general method of finding equivalence classes is as follows:
1972 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1973 Initialize all non-REF nodes to be direct nodes.
1974 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1976 For each constraint containing the dereference, we also do the same
1979 We then compute SCC's in the graph and unify nodes in the same SCC,
1982 For each non-collapsed node x:
1983 Visit all unvisited explicit incoming edges.
1984 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1986 Lookup the equivalence class for pts(x).
1987 If we found one, equivalence_class(x) = found class.
1988 Otherwise, equivalence_class(x) = new class, and new_class is
1989 added to the lookup table.
1991 All direct nodes with the same equivalence class can be replaced
1992 with a single representative node.
1993 All unlabeled nodes (label == 0) are not pointers and all edges
1994 involving them can be eliminated.
1995 We perform these optimizations during rewrite_constraints
1997 In addition to pointer equivalence class finding, we also perform
1998 location equivalence class finding. This is the set of variables
1999 that always appear together in points-to sets. We use this to
2000 compress the size of the points-to sets. */
2002 /* Current maximum pointer equivalence class id. */
2003 static int pointer_equiv_class;
2005 /* Current maximum location equivalence class id. */
2006 static int location_equiv_class;
2008 /* Recursive routine to find strongly connected components in GRAPH,
2009 and label it's nodes with DFS numbers. */
2012 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2016 unsigned int my_dfs;
2018 gcc_assert (si->node_mapping[n] == n);
2019 SET_BIT (si->visited, n);
2020 si->dfs[n] = si->current_index ++;
2021 my_dfs = si->dfs[n];
2023 /* Visit all the successors. */
2024 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2026 unsigned int w = si->node_mapping[i];
2028 if (TEST_BIT (si->deleted, w))
2031 if (!TEST_BIT (si->visited, w))
2032 condense_visit (graph, si, w);
2034 unsigned int t = si->node_mapping[w];
2035 unsigned int nnode = si->node_mapping[n];
2036 gcc_assert (nnode == n);
2038 if (si->dfs[t] < si->dfs[nnode])
2039 si->dfs[n] = si->dfs[t];
2043 /* Visit all the implicit predecessors. */
2044 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2046 unsigned int w = si->node_mapping[i];
2048 if (TEST_BIT (si->deleted, w))
2051 if (!TEST_BIT (si->visited, w))
2052 condense_visit (graph, si, w);
2054 unsigned int t = si->node_mapping[w];
2055 unsigned int nnode = si->node_mapping[n];
2056 gcc_assert (nnode == n);
2058 if (si->dfs[t] < si->dfs[nnode])
2059 si->dfs[n] = si->dfs[t];
2063 /* See if any components have been identified. */
2064 if (si->dfs[n] == my_dfs)
2066 while (VEC_length (unsigned, si->scc_stack) != 0
2067 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2069 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2070 si->node_mapping[w] = n;
2072 if (!TEST_BIT (graph->direct_nodes, w))
2073 RESET_BIT (graph->direct_nodes, n);
2075 /* Unify our nodes. */
2076 if (graph->preds[w])
2078 if (!graph->preds[n])
2079 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2080 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2082 if (graph->implicit_preds[w])
2084 if (!graph->implicit_preds[n])
2085 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2086 bitmap_ior_into (graph->implicit_preds[n],
2087 graph->implicit_preds[w]);
2089 if (graph->points_to[w])
2091 if (!graph->points_to[n])
2092 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2093 bitmap_ior_into (graph->points_to[n],
2094 graph->points_to[w]);
2097 SET_BIT (si->deleted, n);
2100 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2103 /* Label pointer equivalences. */
2106 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2110 SET_BIT (si->visited, n);
2112 if (!graph->points_to[n])
2113 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2115 /* Label and union our incoming edges's points to sets. */
2116 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2118 unsigned int w = si->node_mapping[i];
2119 if (!TEST_BIT (si->visited, w))
2120 label_visit (graph, si, w);
2122 /* Skip unused edges */
2123 if (w == n || graph->pointer_label[w] == 0)
2126 if (graph->points_to[w])
2127 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2129 /* Indirect nodes get fresh variables. */
2130 if (!TEST_BIT (graph->direct_nodes, n))
2131 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2133 if (!bitmap_empty_p (graph->points_to[n]))
2135 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2136 graph->points_to[n]);
2139 label = pointer_equiv_class++;
2140 equiv_class_add (pointer_equiv_class_table,
2141 label, graph->points_to[n]);
2143 graph->pointer_label[n] = label;
2147 /* Perform offline variable substitution, discovering equivalence
2148 classes, and eliminating non-pointer variables. */
2150 static struct scc_info *
2151 perform_var_substitution (constraint_graph_t graph)
2154 unsigned int size = graph->size;
2155 struct scc_info *si = init_scc_info (size);
2157 bitmap_obstack_initialize (&iteration_obstack);
2158 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2159 equiv_class_label_eq, free);
2160 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2161 equiv_class_label_eq, free);
2162 pointer_equiv_class = 1;
2163 location_equiv_class = 1;
2165 /* Condense the nodes, which means to find SCC's, count incoming
2166 predecessors, and unite nodes in SCC's. */
2167 for (i = 0; i < FIRST_REF_NODE; i++)
2168 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2169 condense_visit (graph, si, si->node_mapping[i]);
2171 sbitmap_zero (si->visited);
2172 /* Actually the label the nodes for pointer equivalences */
2173 for (i = 0; i < FIRST_REF_NODE; i++)
2174 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2175 label_visit (graph, si, si->node_mapping[i]);
2177 /* Calculate location equivalence labels. */
2178 for (i = 0; i < FIRST_REF_NODE; i++)
2185 if (!graph->pointed_by[i])
2187 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2189 /* Translate the pointed-by mapping for pointer equivalence
2191 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2193 bitmap_set_bit (pointed_by,
2194 graph->pointer_label[si->node_mapping[j]]);
2196 /* The original pointed_by is now dead. */
2197 BITMAP_FREE (graph->pointed_by[i]);
2199 /* Look up the location equivalence label if one exists, or make
2201 label = equiv_class_lookup (location_equiv_class_table,
2205 label = location_equiv_class++;
2206 equiv_class_add (location_equiv_class_table,
2211 if (dump_file && (dump_flags & TDF_DETAILS))
2212 fprintf (dump_file, "Found location equivalence for node %s\n",
2213 get_varinfo (i)->name);
2214 BITMAP_FREE (pointed_by);
2216 graph->loc_label[i] = label;
2220 if (dump_file && (dump_flags & TDF_DETAILS))
2221 for (i = 0; i < FIRST_REF_NODE; i++)
2223 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2225 "Equivalence classes for %s node id %d:%s are pointer: %d"
2227 direct_node ? "Direct node" : "Indirect node", i,
2228 get_varinfo (i)->name,
2229 graph->pointer_label[si->node_mapping[i]],
2230 graph->loc_label[si->node_mapping[i]]);
2233 /* Quickly eliminate our non-pointer variables. */
2235 for (i = 0; i < FIRST_REF_NODE; i++)
2237 unsigned int node = si->node_mapping[i];
2239 if (graph->pointer_label[node] == 0)
2241 if (dump_file && (dump_flags & TDF_DETAILS))
2243 "%s is a non-pointer variable, eliminating edges.\n",
2244 get_varinfo (node)->name);
2245 stats.nonpointer_vars++;
2246 clear_edges_for_node (graph, node);
2253 /* Free information that was only necessary for variable
2257 free_var_substitution_info (struct scc_info *si)
2260 free (graph->pointer_label);
2261 free (graph->loc_label);
2262 free (graph->pointed_by);
2263 free (graph->points_to);
2264 free (graph->eq_rep);
2265 sbitmap_free (graph->direct_nodes);
2266 htab_delete (pointer_equiv_class_table);
2267 htab_delete (location_equiv_class_table);
2268 bitmap_obstack_release (&iteration_obstack);
2271 /* Return an existing node that is equivalent to NODE, which has
2272 equivalence class LABEL, if one exists. Return NODE otherwise. */
2275 find_equivalent_node (constraint_graph_t graph,
2276 unsigned int node, unsigned int label)
2278 /* If the address version of this variable is unused, we can
2279 substitute it for anything else with the same label.
2280 Otherwise, we know the pointers are equivalent, but not the
2281 locations, and we can unite them later. */
2283 if (!bitmap_bit_p (graph->address_taken, node))
2285 gcc_assert (label < graph->size);
2287 if (graph->eq_rep[label] != -1)
2289 /* Unify the two variables since we know they are equivalent. */
2290 if (unite (graph->eq_rep[label], node))
2291 unify_nodes (graph, graph->eq_rep[label], node, false);
2292 return graph->eq_rep[label];
2296 graph->eq_rep[label] = node;
2297 graph->pe_rep[label] = node;
2302 gcc_assert (label < graph->size);
2303 graph->pe[node] = label;
2304 if (graph->pe_rep[label] == -1)
2305 graph->pe_rep[label] = node;
2311 /* Unite pointer equivalent but not location equivalent nodes in
2312 GRAPH. This may only be performed once variable substitution is
2316 unite_pointer_equivalences (constraint_graph_t graph)
2320 /* Go through the pointer equivalences and unite them to their
2321 representative, if they aren't already. */
2322 for (i = 0; i < FIRST_REF_NODE; i++)
2324 unsigned int label = graph->pe[i];
2327 int label_rep = graph->pe_rep[label];
2329 if (label_rep == -1)
2332 label_rep = find (label_rep);
2333 if (label_rep >= 0 && unite (label_rep, find (i)))
2334 unify_nodes (graph, label_rep, i, false);
2339 /* Move complex constraints to the GRAPH nodes they belong to. */
2342 move_complex_constraints (constraint_graph_t graph)
2347 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2351 struct constraint_expr lhs = c->lhs;
2352 struct constraint_expr rhs = c->rhs;
2354 if (lhs.type == DEREF)
2356 insert_into_complex (graph, lhs.var, c);
2358 else if (rhs.type == DEREF)
2360 if (!(get_varinfo (lhs.var)->is_special_var))
2361 insert_into_complex (graph, rhs.var, c);
2363 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2364 && (lhs.offset != 0 || rhs.offset != 0))
2366 insert_into_complex (graph, rhs.var, c);
2373 /* Optimize and rewrite complex constraints while performing
2374 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2375 result of perform_variable_substitution. */
2378 rewrite_constraints (constraint_graph_t graph,
2379 struct scc_info *si)
2385 for (j = 0; j < graph->size; j++)
2386 gcc_assert (find (j) == j);
2388 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2390 struct constraint_expr lhs = c->lhs;
2391 struct constraint_expr rhs = c->rhs;
2392 unsigned int lhsvar = find (lhs.var);
2393 unsigned int rhsvar = find (rhs.var);
2394 unsigned int lhsnode, rhsnode;
2395 unsigned int lhslabel, rhslabel;
2397 lhsnode = si->node_mapping[lhsvar];
2398 rhsnode = si->node_mapping[rhsvar];
2399 lhslabel = graph->pointer_label[lhsnode];
2400 rhslabel = graph->pointer_label[rhsnode];
2402 /* See if it is really a non-pointer variable, and if so, ignore
2406 if (dump_file && (dump_flags & TDF_DETAILS))
2409 fprintf (dump_file, "%s is a non-pointer variable,"
2410 "ignoring constraint:",
2411 get_varinfo (lhs.var)->name);
2412 dump_constraint (dump_file, c);
2413 fprintf (dump_file, "\n");
2415 VEC_replace (constraint_t, constraints, i, NULL);
2421 if (dump_file && (dump_flags & TDF_DETAILS))
2424 fprintf (dump_file, "%s is a non-pointer variable,"
2425 "ignoring constraint:",
2426 get_varinfo (rhs.var)->name);
2427 dump_constraint (dump_file, c);
2428 fprintf (dump_file, "\n");
2430 VEC_replace (constraint_t, constraints, i, NULL);
2434 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2435 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2436 c->lhs.var = lhsvar;
2437 c->rhs.var = rhsvar;
2442 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2443 part of an SCC, false otherwise. */
2446 eliminate_indirect_cycles (unsigned int node)
2448 if (graph->indirect_cycles[node] != -1
2449 && !bitmap_empty_p (get_varinfo (node)->solution))
2452 VEC(unsigned,heap) *queue = NULL;
2454 unsigned int to = find (graph->indirect_cycles[node]);
2457 /* We can't touch the solution set and call unify_nodes
2458 at the same time, because unify_nodes is going to do
2459 bitmap unions into it. */
2461 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2463 if (find (i) == i && i != to)
2466 VEC_safe_push (unsigned, heap, queue, i);
2471 VEC_iterate (unsigned, queue, queuepos, i);
2474 unify_nodes (graph, to, i, true);
2476 VEC_free (unsigned, heap, queue);
2482 /* Solve the constraint graph GRAPH using our worklist solver.
2483 This is based on the PW* family of solvers from the "Efficient Field
2484 Sensitive Pointer Analysis for C" paper.
2485 It works by iterating over all the graph nodes, processing the complex
2486 constraints and propagating the copy constraints, until everything stops
2487 changed. This corresponds to steps 6-8 in the solving list given above. */
2490 solve_graph (constraint_graph_t graph)
2492 unsigned int size = graph->size;
2496 changed = BITMAP_ALLOC (NULL);
2498 /* Mark all initial non-collapsed nodes as changed. */
2499 for (i = 0; i < size; i++)
2501 varinfo_t ivi = get_varinfo (i);
2502 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2503 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2504 || VEC_length (constraint_t, graph->complex[i]) > 0))
2505 bitmap_set_bit (changed, i);
2508 /* Allocate a bitmap to be used to store the changed bits. */
2509 pts = BITMAP_ALLOC (&pta_obstack);
2511 while (!bitmap_empty_p (changed))
2514 struct topo_info *ti = init_topo_info ();
2517 bitmap_obstack_initialize (&iteration_obstack);
2519 compute_topo_order (graph, ti);
2521 while (VEC_length (unsigned, ti->topo_order) != 0)
2524 i = VEC_pop (unsigned, ti->topo_order);
2526 /* If this variable is not a representative, skip it. */
2530 /* In certain indirect cycle cases, we may merge this
2531 variable to another. */
2532 if (eliminate_indirect_cycles (i) && find (i) != i)
2535 /* If the node has changed, we need to process the
2536 complex constraints and outgoing edges again. */
2537 if (bitmap_clear_bit (changed, i))
2542 VEC(constraint_t,heap) *complex = graph->complex[i];
2543 varinfo_t vi = get_varinfo (i);
2544 bool solution_empty;
2546 /* Compute the changed set of solution bits. */
2547 if (vi->oldsolution)
2548 bitmap_and_compl (pts, vi->solution, vi->oldsolution);
2550 bitmap_copy (pts, vi->solution);
2552 if (bitmap_empty_p (pts))
2555 if (vi->oldsolution)
2556 bitmap_ior_into (vi->oldsolution, pts);
2559 vi->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
2560 bitmap_copy (vi->oldsolution, pts);
2563 solution = vi->solution;
2564 solution_empty = bitmap_empty_p (solution);
2566 /* Process the complex constraints */
2567 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2569 /* XXX: This is going to unsort the constraints in
2570 some cases, which will occasionally add duplicate
2571 constraints during unification. This does not
2572 affect correctness. */
2573 c->lhs.var = find (c->lhs.var);
2574 c->rhs.var = find (c->rhs.var);
2576 /* The only complex constraint that can change our
2577 solution to non-empty, given an empty solution,
2578 is a constraint where the lhs side is receiving
2579 some set from elsewhere. */
2580 if (!solution_empty || c->lhs.type != DEREF)
2581 do_complex_constraint (graph, c, pts);
2584 solution_empty = bitmap_empty_p (solution);
2586 if (!solution_empty)
2589 unsigned eff_escaped_id = find (escaped_id);
2591 /* Propagate solution to all successors. */
2592 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2598 unsigned int to = find (j);
2599 tmp = get_varinfo (to)->solution;
2602 /* Don't try to propagate to ourselves. */
2606 /* If we propagate from ESCAPED use ESCAPED as
2608 if (i == eff_escaped_id)
2609 flag = bitmap_set_bit (tmp, escaped_id);
2611 flag = set_union_with_increment (tmp, pts, 0);
2615 get_varinfo (to)->solution = tmp;
2616 bitmap_set_bit (changed, to);
2622 free_topo_info (ti);
2623 bitmap_obstack_release (&iteration_obstack);
2627 BITMAP_FREE (changed);
2628 bitmap_obstack_release (&oldpta_obstack);
2631 /* Map from trees to variable infos. */
2632 static struct pointer_map_t *vi_for_tree;
2635 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2638 insert_vi_for_tree (tree t, varinfo_t vi)
2640 void **slot = pointer_map_insert (vi_for_tree, t);
2642 gcc_assert (*slot == NULL);
2646 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2647 exist in the map, return NULL, otherwise, return the varinfo we found. */
2650 lookup_vi_for_tree (tree t)
2652 void **slot = pointer_map_contains (vi_for_tree, t);
2656 return (varinfo_t) *slot;
2659 /* Return a printable name for DECL */
2662 alias_get_name (tree decl)
2666 int num_printed = 0;
2668 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2669 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2671 res= get_name (decl);
2679 if (TREE_CODE (decl) == SSA_NAME)
2681 num_printed = asprintf (&temp, "%s_%u",
2682 alias_get_name (SSA_NAME_VAR (decl)),
2683 SSA_NAME_VERSION (decl));
2685 else if (DECL_P (decl))
2687 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2689 if (num_printed > 0)
2691 res = ggc_strdup (temp);
2697 /* Find the variable id for tree T in the map.
2698 If T doesn't exist in the map, create an entry for it and return it. */
2701 get_vi_for_tree (tree t)
2703 void **slot = pointer_map_contains (vi_for_tree, t);
2705 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2707 return (varinfo_t) *slot;
2710 /* Get a scalar constraint expression for a new temporary variable. */
2712 static struct constraint_expr
2713 new_scalar_tmp_constraint_exp (const char *name)
2715 struct constraint_expr tmp;
2718 vi = new_var_info (NULL_TREE, name);
2722 vi->is_full_var = 1;
2731 /* Get a constraint expression vector from an SSA_VAR_P node.
2732 If address_p is true, the result will be taken its address of. */
2735 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2737 struct constraint_expr cexpr;
2740 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2741 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2743 /* For parameters, get at the points-to set for the actual parm
2745 if (TREE_CODE (t) == SSA_NAME
2746 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2747 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2748 && SSA_NAME_IS_DEFAULT_DEF (t))
2750 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2754 /* For global variables resort to the alias target. */
2755 if (TREE_CODE (t) == VAR_DECL
2756 && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
2758 struct varpool_node *node = varpool_get_node (t);
2759 if (node && node->alias)
2761 node = varpool_variable_node (node, NULL);
2766 vi = get_vi_for_tree (t);
2768 cexpr.type = SCALAR;
2770 /* If we determine the result is "anything", and we know this is readonly,
2771 say it points to readonly memory instead. */
2772 if (cexpr.var == anything_id && TREE_READONLY (t))
2775 cexpr.type = ADDRESSOF;
2776 cexpr.var = readonly_id;
2779 /* If we are not taking the address of the constraint expr, add all
2780 sub-fiels of the variable as well. */
2782 && !vi->is_full_var)
2784 for (; vi; vi = vi->next)
2787 VEC_safe_push (ce_s, heap, *results, &cexpr);
2792 VEC_safe_push (ce_s, heap, *results, &cexpr);
2795 /* Process constraint T, performing various simplifications and then
2796 adding it to our list of overall constraints. */
2799 process_constraint (constraint_t t)
2801 struct constraint_expr rhs = t->rhs;
2802 struct constraint_expr lhs = t->lhs;
2804 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2805 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2807 /* If we didn't get any useful constraint from the lhs we get
2808 &ANYTHING as fallback from get_constraint_for. Deal with
2809 it here by turning it into *ANYTHING. */
2810 if (lhs.type == ADDRESSOF
2811 && lhs.var == anything_id)
2814 /* ADDRESSOF on the lhs is invalid. */
2815 gcc_assert (lhs.type != ADDRESSOF);
2817 /* We shouldn't add constraints from things that cannot have pointers.
2818 It's not completely trivial to avoid in the callers, so do it here. */
2819 if (rhs.type != ADDRESSOF
2820 && !get_varinfo (rhs.var)->may_have_pointers)
2823 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2824 if (!get_varinfo (lhs.var)->may_have_pointers)
2827 /* This can happen in our IR with things like n->a = *p */
2828 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2830 /* Split into tmp = *rhs, *lhs = tmp */
2831 struct constraint_expr tmplhs;
2832 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2833 process_constraint (new_constraint (tmplhs, rhs));
2834 process_constraint (new_constraint (lhs, tmplhs));
2836 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2838 /* Split into tmp = &rhs, *lhs = tmp */
2839 struct constraint_expr tmplhs;
2840 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2841 process_constraint (new_constraint (tmplhs, rhs));
2842 process_constraint (new_constraint (lhs, tmplhs));
2846 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2847 VEC_safe_push (constraint_t, heap, constraints, t);
2852 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2855 static HOST_WIDE_INT
2856 bitpos_of_field (const tree fdecl)
2858 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2859 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2862 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2863 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2867 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2868 resulting constraint expressions in *RESULTS. */
2871 get_constraint_for_ptr_offset (tree ptr, tree offset,
2872 VEC (ce_s, heap) **results)
2874 struct constraint_expr c;
2876 HOST_WIDE_INT rhsoffset;
2878 /* If we do not do field-sensitive PTA adding offsets to pointers
2879 does not change the points-to solution. */
2880 if (!use_field_sensitive)
2882 get_constraint_for_rhs (ptr, results);
2886 /* If the offset is not a non-negative integer constant that fits
2887 in a HOST_WIDE_INT, we have to fall back to a conservative
2888 solution which includes all sub-fields of all pointed-to
2889 variables of ptr. */
2890 if (offset == NULL_TREE
2891 || TREE_CODE (offset) != INTEGER_CST)
2892 rhsoffset = UNKNOWN_OFFSET;
2895 /* Sign-extend the offset. */
2897 = double_int_sext (tree_to_double_int (offset),
2898 TYPE_PRECISION (TREE_TYPE (offset)));
2899 if (!double_int_fits_in_shwi_p (soffset))
2900 rhsoffset = UNKNOWN_OFFSET;
2903 /* Make sure the bit-offset also fits. */
2904 HOST_WIDE_INT rhsunitoffset = soffset.low;
2905 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2906 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2907 rhsoffset = UNKNOWN_OFFSET;
2911 get_constraint_for_rhs (ptr, results);
2915 /* As we are eventually appending to the solution do not use
2916 VEC_iterate here. */
2917 n = VEC_length (ce_s, *results);
2918 for (j = 0; j < n; j++)
2921 c = *VEC_index (ce_s, *results, j);
2922 curr = get_varinfo (c.var);
2924 if (c.type == ADDRESSOF
2925 /* If this varinfo represents a full variable just use it. */
2926 && curr->is_full_var)
2928 else if (c.type == ADDRESSOF
2929 /* If we do not know the offset add all subfields. */
2930 && rhsoffset == UNKNOWN_OFFSET)
2932 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2935 struct constraint_expr c2;
2937 c2.type = ADDRESSOF;
2939 if (c2.var != c.var)
2940 VEC_safe_push (ce_s, heap, *results, &c2);
2945 else if (c.type == ADDRESSOF)
2948 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2950 /* Search the sub-field which overlaps with the
2951 pointed-to offset. If the result is outside of the variable
2952 we have to provide a conservative result, as the variable is
2953 still reachable from the resulting pointer (even though it
2954 technically cannot point to anything). The last and first
2955 sub-fields are such conservative results.
2956 ??? If we always had a sub-field for &object + 1 then
2957 we could represent this in a more precise way. */
2959 && curr->offset < offset)
2961 temp = first_or_preceding_vi_for_offset (curr, offset);
2963 /* If the found variable is not exactly at the pointed to
2964 result, we have to include the next variable in the
2965 solution as well. Otherwise two increments by offset / 2
2966 do not result in the same or a conservative superset
2968 if (temp->offset != offset
2969 && temp->next != NULL)
2971 struct constraint_expr c2;
2972 c2.var = temp->next->id;
2973 c2.type = ADDRESSOF;
2975 VEC_safe_push (ce_s, heap, *results, &c2);
2981 c.offset = rhsoffset;
2983 VEC_replace (ce_s, *results, j, &c);
2988 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2989 If address_p is true the result will be taken its address of.
2990 If lhs_p is true then the constraint expression is assumed to be used
2994 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2995 bool address_p, bool lhs_p)
2998 HOST_WIDE_INT bitsize = -1;
2999 HOST_WIDE_INT bitmaxsize = -1;
3000 HOST_WIDE_INT bitpos;
3002 struct constraint_expr *result;
3004 /* Some people like to do cute things like take the address of
3007 while (handled_component_p (forzero)
3008 || INDIRECT_REF_P (forzero)
3009 || TREE_CODE (forzero) == MEM_REF)
3010 forzero = TREE_OPERAND (forzero, 0);
3012 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3014 struct constraint_expr temp;
3017 temp.var = integer_id;
3019 VEC_safe_push (ce_s, heap, *results, &temp);
3023 /* Handle type-punning through unions. If we are extracting a pointer
3024 from a union via a possibly type-punning access that pointer
3025 points to anything, similar to a conversion of an integer to
3031 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3032 u = TREE_OPERAND (u, 0))
3033 if (TREE_CODE (u) == COMPONENT_REF
3034 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3036 struct constraint_expr temp;
3039 temp.var = anything_id;
3040 temp.type = ADDRESSOF;
3041 VEC_safe_push (ce_s, heap, *results, &temp);
3046 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3048 /* Pretend to take the address of the base, we'll take care of
3049 adding the required subset of sub-fields below. */
3050 get_constraint_for_1 (t, results, true, lhs_p);
3051 gcc_assert (VEC_length (ce_s, *results) == 1);
3052 result = VEC_last (ce_s, *results);
3054 if (result->type == SCALAR
3055 && get_varinfo (result->var)->is_full_var)
3056 /* For single-field vars do not bother about the offset. */
3058 else if (result->type == SCALAR)
3060 /* In languages like C, you can access one past the end of an
3061 array. You aren't allowed to dereference it, so we can
3062 ignore this constraint. When we handle pointer subtraction,
3063 we may have to do something cute here. */
3065 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3068 /* It's also not true that the constraint will actually start at the
3069 right offset, it may start in some padding. We only care about
3070 setting the constraint to the first actual field it touches, so
3072 struct constraint_expr cexpr = *result;
3074 VEC_pop (ce_s, *results);
3076 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3078 if (ranges_overlap_p (curr->offset, curr->size,
3079 bitpos, bitmaxsize))
3081 cexpr.var = curr->id;
3082 VEC_safe_push (ce_s, heap, *results, &cexpr);
3087 /* If we are going to take the address of this field then
3088 to be able to compute reachability correctly add at least
3089 the last field of the variable. */
3091 && VEC_length (ce_s, *results) == 0)
3093 curr = get_varinfo (cexpr.var);
3094 while (curr->next != NULL)
3096 cexpr.var = curr->id;
3097 VEC_safe_push (ce_s, heap, *results, &cexpr);
3099 else if (VEC_length (ce_s, *results) == 0)
3100 /* Assert that we found *some* field there. The user couldn't be
3101 accessing *only* padding. */
3102 /* Still the user could access one past the end of an array
3103 embedded in a struct resulting in accessing *only* padding. */
3104 /* Or accessing only padding via type-punning to a type
3105 that has a filed just in padding space. */
3107 cexpr.type = SCALAR;
3108 cexpr.var = anything_id;
3110 VEC_safe_push (ce_s, heap, *results, &cexpr);
3113 else if (bitmaxsize == 0)
3115 if (dump_file && (dump_flags & TDF_DETAILS))
3116 fprintf (dump_file, "Access to zero-sized part of variable,"
3120 if (dump_file && (dump_flags & TDF_DETAILS))
3121 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3123 else if (result->type == DEREF)
3125 /* If we do not know exactly where the access goes say so. Note
3126 that only for non-structure accesses we know that we access
3127 at most one subfiled of any variable. */
3129 || bitsize != bitmaxsize
3130 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3131 || result->offset == UNKNOWN_OFFSET)
3132 result->offset = UNKNOWN_OFFSET;
3134 result->offset += bitpos;
3136 else if (result->type == ADDRESSOF)
3138 /* We can end up here for component references on a
3139 VIEW_CONVERT_EXPR <>(&foobar). */
3140 result->type = SCALAR;
3141 result->var = anything_id;
3149 /* Dereference the constraint expression CONS, and return the result.
3150 DEREF (ADDRESSOF) = SCALAR
3151 DEREF (SCALAR) = DEREF
3152 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3153 This is needed so that we can handle dereferencing DEREF constraints. */
3156 do_deref (VEC (ce_s, heap) **constraints)
3158 struct constraint_expr *c;
3161 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3163 if (c->type == SCALAR)
3165 else if (c->type == ADDRESSOF)
3167 else if (c->type == DEREF)
3169 struct constraint_expr tmplhs;
3170 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3171 process_constraint (new_constraint (tmplhs, *c));
3172 c->var = tmplhs.var;
3179 /* Given a tree T, return the constraint expression for taking the
3183 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3185 struct constraint_expr *c;
3188 get_constraint_for_1 (t, results, true, true);
3190 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3192 if (c->type == DEREF)
3195 c->type = ADDRESSOF;
3199 /* Given a tree T, return the constraint expression for it. */
3202 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3205 struct constraint_expr temp;
3207 /* x = integer is all glommed to a single variable, which doesn't
3208 point to anything by itself. That is, of course, unless it is an
3209 integer constant being treated as a pointer, in which case, we
3210 will return that this is really the addressof anything. This
3211 happens below, since it will fall into the default case. The only
3212 case we know something about an integer treated like a pointer is
3213 when it is the NULL pointer, and then we just say it points to
3216 Do not do that if -fno-delete-null-pointer-checks though, because
3217 in that case *NULL does not fail, so it _should_ alias *anything.
3218 It is not worth adding a new option or renaming the existing one,
3219 since this case is relatively obscure. */
3220 if ((TREE_CODE (t) == INTEGER_CST
3221 && integer_zerop (t))
3222 /* The only valid CONSTRUCTORs in gimple with pointer typed
3223 elements are zero-initializer. But in IPA mode we also
3224 process global initializers, so verify at least. */
3225 || (TREE_CODE (t) == CONSTRUCTOR
3226 && CONSTRUCTOR_NELTS (t) == 0))
3228 if (flag_delete_null_pointer_checks)
3229 temp.var = nothing_id;
3231 temp.var = nonlocal_id;
3232 temp.type = ADDRESSOF;
3234 VEC_safe_push (ce_s, heap, *results, &temp);
3238 /* String constants are read-only. */
3239 if (TREE_CODE (t) == STRING_CST)
3241 temp.var = readonly_id;
3244 VEC_safe_push (ce_s, heap, *results, &temp);
3248 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3250 case tcc_expression:
3252 switch (TREE_CODE (t))
3255 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3263 switch (TREE_CODE (t))
3267 struct constraint_expr cs;
3269 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
3270 TREE_OPERAND (t, 1), results);
3273 /* If we are not taking the address then make sure to process
3274 all subvariables we might access. */
3278 cs = *VEC_last (ce_s, *results);
3279 if (cs.type == DEREF
3280 && type_can_have_subvars (TREE_TYPE (t)))
3282 /* For dereferences this means we have to defer it
3284 VEC_last (ce_s, *results)->offset = UNKNOWN_OFFSET;
3287 if (cs.type != SCALAR)
3290 vi = get_varinfo (cs.var);
3292 if (!vi->is_full_var
3295 unsigned HOST_WIDE_INT size;
3296 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3297 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3300 for (; curr; curr = curr->next)
3302 if (curr->offset - vi->offset < size)
3305 VEC_safe_push (ce_s, heap, *results, &cs);
3314 case ARRAY_RANGE_REF:
3316 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3318 case VIEW_CONVERT_EXPR:
3319 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3322 /* We are missing handling for TARGET_MEM_REF here. */
3327 case tcc_exceptional:
3329 switch (TREE_CODE (t))
3333 get_constraint_for_ssa_var (t, results, address_p);
3340 VEC (ce_s, heap) *tmp = NULL;
3341 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3343 struct constraint_expr *rhsp;
3345 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3346 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3347 VEC_safe_push (ce_s, heap, *results, rhsp);
3348 VEC_truncate (ce_s, tmp, 0);
3350 VEC_free (ce_s, heap, tmp);
3351 /* We do not know whether the constructor was complete,
3352 so technically we have to add &NOTHING or &ANYTHING
3353 like we do for an empty constructor as well. */
3360 case tcc_declaration:
3362 get_constraint_for_ssa_var (t, results, address_p);
3367 /* We cannot refer to automatic variables through constants. */
3368 temp.type = ADDRESSOF;
3369 temp.var = nonlocal_id;
3371 VEC_safe_push (ce_s, heap, *results, &temp);
3377 /* The default fallback is a constraint from anything. */
3378 temp.type = ADDRESSOF;
3379 temp.var = anything_id;
3381 VEC_safe_push (ce_s, heap, *results, &temp);
3384 /* Given a gimple tree T, return the constraint expression vector for it. */
3387 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3389 gcc_assert (VEC_length (ce_s, *results) == 0);
3391 get_constraint_for_1 (t, results, false, true);
3394 /* Given a gimple tree T, return the constraint expression vector for it
3395 to be used as the rhs of a constraint. */
3398 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3400 gcc_assert (VEC_length (ce_s, *results) == 0);
3402 get_constraint_for_1 (t, results, false, false);
3406 /* Efficiently generates constraints from all entries in *RHSC to all
3407 entries in *LHSC. */
3410 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3412 struct constraint_expr *lhsp, *rhsp;
3415 if (VEC_length (ce_s, lhsc) <= 1
3416 || VEC_length (ce_s, rhsc) <= 1)
3418 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3419 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3420 process_constraint (new_constraint (*lhsp, *rhsp));
3424 struct constraint_expr tmp;
3425 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3426 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3427 process_constraint (new_constraint (tmp, *rhsp));
3428 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3429 process_constraint (new_constraint (*lhsp, tmp));
3433 /* Handle aggregate copies by expanding into copies of the respective
3434 fields of the structures. */
3437 do_structure_copy (tree lhsop, tree rhsop)
3439 struct constraint_expr *lhsp, *rhsp;
3440 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3443 get_constraint_for (lhsop, &lhsc);
3444 get_constraint_for_rhs (rhsop, &rhsc);
3445 lhsp = VEC_index (ce_s, lhsc, 0);
3446 rhsp = VEC_index (ce_s, rhsc, 0);
3447 if (lhsp->type == DEREF
3448 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3449 || rhsp->type == DEREF)
3451 if (lhsp->type == DEREF)
3453 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3454 lhsp->offset = UNKNOWN_OFFSET;
3456 if (rhsp->type == DEREF)
3458 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3459 rhsp->offset = UNKNOWN_OFFSET;
3461 process_all_all_constraints (lhsc, rhsc);
3463 else if (lhsp->type == SCALAR
3464 && (rhsp->type == SCALAR
3465 || rhsp->type == ADDRESSOF))
3467 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3468 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3470 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3471 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3472 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3474 varinfo_t lhsv, rhsv;
3475 rhsp = VEC_index (ce_s, rhsc, k);
3476 lhsv = get_varinfo (lhsp->var);
3477 rhsv = get_varinfo (rhsp->var);
3478 if (lhsv->may_have_pointers
3479 && (lhsv->is_full_var
3480 || rhsv->is_full_var
3481 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3482 rhsv->offset + lhsoffset, rhsv->size)))
3483 process_constraint (new_constraint (*lhsp, *rhsp));
3484 if (!rhsv->is_full_var
3485 && (lhsv->is_full_var
3486 || (lhsv->offset + rhsoffset + lhsv->size
3487 > rhsv->offset + lhsoffset + rhsv->size)))
3490 if (k >= VEC_length (ce_s, rhsc))
3500 VEC_free (ce_s, heap, lhsc);
3501 VEC_free (ce_s, heap, rhsc);
3504 /* Create constraints ID = { rhsc }. */
3507 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3509 struct constraint_expr *c;
3510 struct constraint_expr includes;
3514 includes.offset = 0;
3515 includes.type = SCALAR;
3517 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3518 process_constraint (new_constraint (includes, *c));
3521 /* Create a constraint ID = OP. */
3524 make_constraint_to (unsigned id, tree op)
3526 VEC(ce_s, heap) *rhsc = NULL;
3527 get_constraint_for_rhs (op, &rhsc);
3528 make_constraints_to (id, rhsc);
3529 VEC_free (ce_s, heap, rhsc);
3532 /* Create a constraint ID = &FROM. */
3535 make_constraint_from (varinfo_t vi, int from)
3537 struct constraint_expr lhs, rhs;
3545 rhs.type = ADDRESSOF;
3546 process_constraint (new_constraint (lhs, rhs));
3549 /* Create a constraint ID = FROM. */
3552 make_copy_constraint (varinfo_t vi, int from)
3554 struct constraint_expr lhs, rhs;
3563 process_constraint (new_constraint (lhs, rhs));
3566 /* Make constraints necessary to make OP escape. */
3569 make_escape_constraint (tree op)
3571 make_constraint_to (escaped_id, op);
3574 /* Add constraints to that the solution of VI is transitively closed. */
3577 make_transitive_closure_constraints (varinfo_t vi)
3579 struct constraint_expr lhs, rhs;
3588 process_constraint (new_constraint (lhs, rhs));
3590 /* VAR = VAR + UNKNOWN; */
3596 rhs.offset = UNKNOWN_OFFSET;
3597 process_constraint (new_constraint (lhs, rhs));
3600 /* Temporary storage for fake var decls. */
3601 struct obstack fake_var_decl_obstack;
3603 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
3606 build_fake_var_decl (tree type)
3608 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
3609 memset (decl, 0, sizeof (struct tree_var_decl));
3610 TREE_SET_CODE (decl, VAR_DECL);
3611 TREE_TYPE (decl) = type;
3612 DECL_UID (decl) = allocate_decl_uid ();
3613 SET_DECL_PT_UID (decl, -1);
3614 layout_decl (decl, 0);
3618 /* Create a new artificial heap variable with NAME.
3619 Return the created variable. */
3622 make_heapvar (const char *name)
3627 heapvar = build_fake_var_decl (ptr_type_node);
3628 DECL_EXTERNAL (heapvar) = 1;
3630 vi = new_var_info (heapvar, name);
3631 vi->is_artificial_var = true;
3632 vi->is_heap_var = true;
3633 vi->is_unknown_size_var = true;
3637 vi->is_full_var = true;
3638 insert_vi_for_tree (heapvar, vi);
3643 /* Create a new artificial heap variable with NAME and make a
3644 constraint from it to LHS. Set flags according to a tag used
3645 for tracking restrict pointers. */
3648 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3650 varinfo_t vi = make_heapvar (name);
3651 vi->is_global_var = 1;
3652 vi->may_have_pointers = 1;
3653 make_constraint_from (lhs, vi->id);
3657 /* Create a new artificial heap variable with NAME and make a
3658 constraint from it to LHS. Set flags according to a tag used
3659 for tracking restrict pointers and make the artificial heap
3660 point to global memory. */
3663 make_constraint_from_global_restrict (varinfo_t lhs, const char *name)
3665 varinfo_t vi = make_constraint_from_restrict (lhs, name);
3666 make_copy_constraint (vi, nonlocal_id);
3670 /* In IPA mode there are varinfos for different aspects of reach
3671 function designator. One for the points-to set of the return
3672 value, one for the variables that are clobbered by the function,
3673 one for its uses and one for each parameter (including a single
3674 glob for remaining variadic arguments). */
3676 enum { fi_clobbers = 1, fi_uses = 2,
3677 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3679 /* Get a constraint for the requested part of a function designator FI
3680 when operating in IPA mode. */
3682 static struct constraint_expr
3683 get_function_part_constraint (varinfo_t fi, unsigned part)
3685 struct constraint_expr c;
3687 gcc_assert (in_ipa_mode);
3689 if (fi->id == anything_id)
3691 /* ??? We probably should have a ANYFN special variable. */
3692 c.var = anything_id;
3696 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3698 varinfo_t ai = first_vi_for_offset (fi, part);
3702 c.var = anything_id;
3716 /* For non-IPA mode, generate constraints necessary for a call on the
3720 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3722 struct constraint_expr rhsc;
3724 bool returns_uses = false;
3726 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3728 tree arg = gimple_call_arg (stmt, i);
3729 int flags = gimple_call_arg_flags (stmt, i);
3731 /* If the argument is not used we can ignore it. */
3732 if (flags & EAF_UNUSED)
3735 /* As we compute ESCAPED context-insensitive we do not gain
3736 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3737 set. The argument would still get clobbered through the
3739 ??? We might get away with less (and more precise) constraints
3740 if using a temporary for transitively closing things. */
3741 if ((flags & EAF_NOCLOBBER)
3742 && (flags & EAF_NOESCAPE))
3744 varinfo_t uses = get_call_use_vi (stmt);
3745 if (!(flags & EAF_DIRECT))
3746 make_transitive_closure_constraints (uses);
3747 make_constraint_to (uses->id, arg);
3748 returns_uses = true;
3750 else if (flags & EAF_NOESCAPE)
3752 varinfo_t uses = get_call_use_vi (stmt);
3753 varinfo_t clobbers = get_call_clobber_vi (stmt);
3754 if (!(flags & EAF_DIRECT))
3756 make_transitive_closure_constraints (uses);
3757 make_transitive_closure_constraints (clobbers);
3759 make_constraint_to (uses->id, arg);
3760 make_constraint_to (clobbers->id, arg);
3761 returns_uses = true;
3764 make_escape_constraint (arg);
3767 /* If we added to the calls uses solution make sure we account for
3768 pointers to it to be returned. */
3771 rhsc.var = get_call_use_vi (stmt)->id;
3774 VEC_safe_push (ce_s, heap, *results, &rhsc);
3777 /* The static chain escapes as well. */
3778 if (gimple_call_chain (stmt))
3779 make_escape_constraint (gimple_call_chain (stmt));
3781 /* And if we applied NRV the address of the return slot escapes as well. */
3782 if (gimple_call_return_slot_opt_p (stmt)
3783 && gimple_call_lhs (stmt) != NULL_TREE
3784 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3786 VEC(ce_s, heap) *tmpc = NULL;
3787 struct constraint_expr lhsc, *c;
3788 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3789 lhsc.var = escaped_id;
3792 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3793 process_constraint (new_constraint (lhsc, *c));
3794 VEC_free(ce_s, heap, tmpc);
3797 /* Regular functions return nonlocal memory. */
3798 rhsc.var = nonlocal_id;
3801 VEC_safe_push (ce_s, heap, *results, &rhsc);
3804 /* For non-IPA mode, generate constraints necessary for a call
3805 that returns a pointer and assigns it to LHS. This simply makes
3806 the LHS point to global and escaped variables. */
3809 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3812 VEC(ce_s, heap) *lhsc = NULL;
3814 get_constraint_for (lhs, &lhsc);
3815 /* If the store is to a global decl make sure to
3816 add proper escape constraints. */
3817 lhs = get_base_address (lhs);
3820 && is_global_var (lhs))
3822 struct constraint_expr tmpc;
3823 tmpc.var = escaped_id;
3826 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3829 /* If the call returns an argument unmodified override the rhs
3831 flags = gimple_call_return_flags (stmt);
3832 if (flags & ERF_RETURNS_ARG
3833 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3837 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3838 get_constraint_for (arg, &rhsc);
3839 process_all_all_constraints (lhsc, rhsc);
3840 VEC_free (ce_s, heap, rhsc);
3842 else if (flags & ERF_NOALIAS)
3845 struct constraint_expr tmpc;
3847 vi = make_heapvar ("HEAP");
3848 /* We delay marking allocated storage global until we know if
3850 DECL_EXTERNAL (vi->decl) = 0;
3851 vi->is_global_var = 0;
3852 /* If this is not a real malloc call assume the memory was
3853 initialized and thus may point to global memory. All
3854 builtin functions with the malloc attribute behave in a sane way. */
3856 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3857 make_constraint_from (vi, nonlocal_id);
3860 tmpc.type = ADDRESSOF;
3861 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3864 process_all_all_constraints (lhsc, rhsc);
3866 VEC_free (ce_s, heap, lhsc);
3869 /* For non-IPA mode, generate constraints necessary for a call of a
3870 const function that returns a pointer in the statement STMT. */
3873 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3875 struct constraint_expr rhsc;
3878 /* Treat nested const functions the same as pure functions as far
3879 as the static chain is concerned. */
3880 if (gimple_call_chain (stmt))
3882 varinfo_t uses = get_call_use_vi (stmt);
3883 make_transitive_closure_constraints (uses);
3884 make_constraint_to (uses->id, gimple_call_chain (stmt));
3885 rhsc.var = uses->id;
3888 VEC_safe_push (ce_s, heap, *results, &rhsc);
3891 /* May return arguments. */
3892 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3894 tree arg = gimple_call_arg (stmt, k);
3895 VEC(ce_s, heap) *argc = NULL;
3897 struct constraint_expr *argp;
3898 get_constraint_for_rhs (arg, &argc);
3899 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3900 VEC_safe_push (ce_s, heap, *results, argp);
3901 VEC_free(ce_s, heap, argc);
3904 /* May return addresses of globals. */
3905 rhsc.var = nonlocal_id;
3907 rhsc.type = ADDRESSOF;
3908 VEC_safe_push (ce_s, heap, *results, &rhsc);
3911 /* For non-IPA mode, generate constraints necessary for a call to a
3912 pure function in statement STMT. */
3915 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3917 struct constraint_expr rhsc;
3919 varinfo_t uses = NULL;
3921 /* Memory reached from pointer arguments is call-used. */
3922 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3924 tree arg = gimple_call_arg (stmt, i);
3927 uses = get_call_use_vi (stmt);
3928 make_transitive_closure_constraints (uses);
3930 make_constraint_to (uses->id, arg);
3933 /* The static chain is used as well. */
3934 if (gimple_call_chain (stmt))
3938 uses = get_call_use_vi (stmt);
3939 make_transitive_closure_constraints (uses);
3941 make_constraint_to (uses->id, gimple_call_chain (stmt));
3944 /* Pure functions may return call-used and nonlocal memory. */
3947 rhsc.var = uses->id;
3950 VEC_safe_push (ce_s, heap, *results, &rhsc);
3952 rhsc.var = nonlocal_id;
3955 VEC_safe_push (ce_s, heap, *results, &rhsc);
3959 /* Return the varinfo for the callee of CALL. */
3962 get_fi_for_callee (gimple call)
3964 tree decl, fn = gimple_call_fn (call);
3966 if (fn && TREE_CODE (fn) == OBJ_TYPE_REF)
3967 fn = OBJ_TYPE_REF_EXPR (fn);
3969 /* If we can directly resolve the function being called, do so.
3970 Otherwise, it must be some sort of indirect expression that
3971 we should still be able to handle. */
3972 decl = gimple_call_addr_fndecl (fn);
3974 return get_vi_for_tree (decl);
3976 /* If the function is anything other than a SSA name pointer we have no
3977 clue and should be getting ANYFN (well, ANYTHING for now). */
3978 if (!fn || TREE_CODE (fn) != SSA_NAME)
3979 return get_varinfo (anything_id);
3981 if ((TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL
3982 || TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL)
3983 && SSA_NAME_IS_DEFAULT_DEF (fn))
3984 fn = SSA_NAME_VAR (fn);
3986 return get_vi_for_tree (fn);
3989 /* Create constraints for the builtin call T. Return true if the call
3990 was handled, otherwise false. */
3993 find_func_aliases_for_builtin_call (gimple t)
3995 tree fndecl = gimple_call_fndecl (t);
3996 VEC(ce_s, heap) *lhsc = NULL;
3997 VEC(ce_s, heap) *rhsc = NULL;
4000 if (fndecl != NULL_TREE
4001 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4002 /* ??? All builtins that are handled here need to be handled
4003 in the alias-oracle query functions explicitly! */
4004 switch (DECL_FUNCTION_CODE (fndecl))
4006 /* All the following functions return a pointer to the same object
4007 as their first argument points to. The functions do not add
4008 to the ESCAPED solution. The functions make the first argument
4009 pointed to memory point to what the second argument pointed to
4010 memory points to. */
4011 case BUILT_IN_STRCPY:
4012 case BUILT_IN_STRNCPY:
4013 case BUILT_IN_BCOPY:
4014 case BUILT_IN_MEMCPY:
4015 case BUILT_IN_MEMMOVE:
4016 case BUILT_IN_MEMPCPY:
4017 case BUILT_IN_STPCPY:
4018 case BUILT_IN_STPNCPY:
4019 case BUILT_IN_STRCAT:
4020 case BUILT_IN_STRNCAT:
4021 case BUILT_IN_STRCPY_CHK:
4022 case BUILT_IN_STRNCPY_CHK:
4023 case BUILT_IN_MEMCPY_CHK:
4024 case BUILT_IN_MEMMOVE_CHK:
4025 case BUILT_IN_MEMPCPY_CHK:
4026 case BUILT_IN_STPCPY_CHK:
4027 case BUILT_IN_STPNCPY_CHK:
4028 case BUILT_IN_STRCAT_CHK:
4029 case BUILT_IN_STRNCAT_CHK:
4030 case BUILT_IN_TM_MEMCPY:
4031 case BUILT_IN_TM_MEMMOVE:
4033 tree res = gimple_call_lhs (t);
4034 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4035 == BUILT_IN_BCOPY ? 1 : 0));
4036 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4037 == BUILT_IN_BCOPY ? 0 : 1));
4038 if (res != NULL_TREE)
4040 get_constraint_for (res, &lhsc);
4041 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4042 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4043 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY
4044 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHK
4045 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY_CHK
4046 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY_CHK)
4047 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4049 get_constraint_for (dest, &rhsc);
4050 process_all_all_constraints (lhsc, rhsc);
4051 VEC_free (ce_s, heap, lhsc);
4052 VEC_free (ce_s, heap, rhsc);
4054 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4055 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4058 process_all_all_constraints (lhsc, rhsc);
4059 VEC_free (ce_s, heap, lhsc);
4060 VEC_free (ce_s, heap, rhsc);
4063 case BUILT_IN_MEMSET:
4064 case BUILT_IN_MEMSET_CHK:
4065 case BUILT_IN_TM_MEMSET:
4067 tree res = gimple_call_lhs (t);
4068 tree dest = gimple_call_arg (t, 0);
4071 struct constraint_expr ac;
4072 if (res != NULL_TREE)
4074 get_constraint_for (res, &lhsc);
4075 get_constraint_for (dest, &rhsc);
4076 process_all_all_constraints (lhsc, rhsc);
4077 VEC_free (ce_s, heap, lhsc);
4078 VEC_free (ce_s, heap, rhsc);
4080 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4082 if (flag_delete_null_pointer_checks
4083 && integer_zerop (gimple_call_arg (t, 1)))
4085 ac.type = ADDRESSOF;
4086 ac.var = nothing_id;
4091 ac.var = integer_id;
4094 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4095 process_constraint (new_constraint (*lhsp, ac));
4096 VEC_free (ce_s, heap, lhsc);
4099 case BUILT_IN_ASSUME_ALIGNED:
4101 tree res = gimple_call_lhs (t);
4102 tree dest = gimple_call_arg (t, 0);
4103 if (res != NULL_TREE)
4105 get_constraint_for (res, &lhsc);
4106 get_constraint_for (dest, &rhsc);
4107 process_all_all_constraints (lhsc, rhsc);
4108 VEC_free (ce_s, heap, lhsc);
4109 VEC_free (ce_s, heap, rhsc);
4113 /* All the following functions do not return pointers, do not
4114 modify the points-to sets of memory reachable from their
4115 arguments and do not add to the ESCAPED solution. */
4116 case BUILT_IN_SINCOS:
4117 case BUILT_IN_SINCOSF:
4118 case BUILT_IN_SINCOSL:
4119 case BUILT_IN_FREXP:
4120 case BUILT_IN_FREXPF:
4121 case BUILT_IN_FREXPL:
4122 case BUILT_IN_GAMMA_R:
4123 case BUILT_IN_GAMMAF_R:
4124 case BUILT_IN_GAMMAL_R:
4125 case BUILT_IN_LGAMMA_R:
4126 case BUILT_IN_LGAMMAF_R:
4127 case BUILT_IN_LGAMMAL_R:
4129 case BUILT_IN_MODFF:
4130 case BUILT_IN_MODFL:
4131 case BUILT_IN_REMQUO:
4132 case BUILT_IN_REMQUOF:
4133 case BUILT_IN_REMQUOL:
4136 case BUILT_IN_STRDUP:
4137 case BUILT_IN_STRNDUP:
4138 if (gimple_call_lhs (t))
4140 handle_lhs_call (t, gimple_call_lhs (t), gimple_call_flags (t),
4142 get_constraint_for_ptr_offset (gimple_call_lhs (t),
4144 get_constraint_for_ptr_offset (gimple_call_arg (t, 0),
4148 process_all_all_constraints (lhsc, rhsc);
4149 VEC_free (ce_s, heap, lhsc);
4150 VEC_free (ce_s, heap, rhsc);
4154 /* Trampolines are special - they set up passing the static
4156 case BUILT_IN_INIT_TRAMPOLINE:
4158 tree tramp = gimple_call_arg (t, 0);
4159 tree nfunc = gimple_call_arg (t, 1);
4160 tree frame = gimple_call_arg (t, 2);
4162 struct constraint_expr lhs, *rhsp;
4165 varinfo_t nfi = NULL;
4166 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4167 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4170 lhs = get_function_part_constraint (nfi, fi_static_chain);
4171 get_constraint_for (frame, &rhsc);
4172 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4173 process_constraint (new_constraint (lhs, *rhsp));
4174 VEC_free (ce_s, heap, rhsc);
4176 /* Make the frame point to the function for
4177 the trampoline adjustment call. */
4178 get_constraint_for (tramp, &lhsc);
4180 get_constraint_for (nfunc, &rhsc);
4181 process_all_all_constraints (lhsc, rhsc);
4182 VEC_free (ce_s, heap, rhsc);
4183 VEC_free (ce_s, heap, lhsc);
4188 /* Else fallthru to generic handling which will let
4189 the frame escape. */
4192 case BUILT_IN_ADJUST_TRAMPOLINE:
4194 tree tramp = gimple_call_arg (t, 0);
4195 tree res = gimple_call_lhs (t);
4196 if (in_ipa_mode && res)
4198 get_constraint_for (res, &lhsc);
4199 get_constraint_for (tramp, &rhsc);
4201 process_all_all_constraints (lhsc, rhsc);
4202 VEC_free (ce_s, heap, rhsc);
4203 VEC_free (ce_s, heap, lhsc);
4207 CASE_BUILT_IN_TM_STORE (1):
4208 CASE_BUILT_IN_TM_STORE (2):
4209 CASE_BUILT_IN_TM_STORE (4):
4210 CASE_BUILT_IN_TM_STORE (8):
4211 CASE_BUILT_IN_TM_STORE (FLOAT):
4212 CASE_BUILT_IN_TM_STORE (DOUBLE):
4213 CASE_BUILT_IN_TM_STORE (LDOUBLE):
4214 CASE_BUILT_IN_TM_STORE (M64):
4215 CASE_BUILT_IN_TM_STORE (M128):
4216 CASE_BUILT_IN_TM_STORE (M256):
4218 tree addr = gimple_call_arg (t, 0);
4219 tree src = gimple_call_arg (t, 1);
4221 get_constraint_for (addr, &lhsc);
4223 get_constraint_for (src, &rhsc);
4224 process_all_all_constraints (lhsc, rhsc);
4225 VEC_free (ce_s, heap, lhsc);
4226 VEC_free (ce_s, heap, rhsc);
4229 CASE_BUILT_IN_TM_LOAD (1):
4230 CASE_BUILT_IN_TM_LOAD (2):
4231 CASE_BUILT_IN_TM_LOAD (4):
4232 CASE_BUILT_IN_TM_LOAD (8):
4233 CASE_BUILT_IN_TM_LOAD (FLOAT):
4234 CASE_BUILT_IN_TM_LOAD (DOUBLE):
4235 CASE_BUILT_IN_TM_LOAD (LDOUBLE):
4236 CASE_BUILT_IN_TM_LOAD (M64):
4237 CASE_BUILT_IN_TM_LOAD (M128):
4238 CASE_BUILT_IN_TM_LOAD (M256):
4240 tree dest = gimple_call_lhs (t);
4241 tree addr = gimple_call_arg (t, 0);
4243 get_constraint_for (dest, &lhsc);
4244 get_constraint_for (addr, &rhsc);
4246 process_all_all_constraints (lhsc, rhsc);
4247 VEC_free (ce_s, heap, lhsc);
4248 VEC_free (ce_s, heap, rhsc);
4251 /* Variadic argument handling needs to be handled in IPA
4253 case BUILT_IN_VA_START:
4255 tree valist = gimple_call_arg (t, 0);
4256 struct constraint_expr rhs, *lhsp;
4258 get_constraint_for (valist, &lhsc);
4260 /* The va_list gets access to pointers in variadic
4261 arguments. Which we know in the case of IPA analysis
4262 and otherwise are just all nonlocal variables. */
4265 fi = lookup_vi_for_tree (cfun->decl);
4266 rhs = get_function_part_constraint (fi, ~0);
4267 rhs.type = ADDRESSOF;
4271 rhs.var = nonlocal_id;
4272 rhs.type = ADDRESSOF;
4275 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4276 process_constraint (new_constraint (*lhsp, rhs));
4277 VEC_free (ce_s, heap, lhsc);
4278 /* va_list is clobbered. */
4279 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4282 /* va_end doesn't have any effect that matters. */
4283 case BUILT_IN_VA_END:
4285 /* Alternate return. Simply give up for now. */
4286 case BUILT_IN_RETURN:
4290 || !(fi = get_vi_for_tree (cfun->decl)))
4291 make_constraint_from (get_varinfo (escaped_id), anything_id);
4292 else if (in_ipa_mode
4295 struct constraint_expr lhs, rhs;
4296 lhs = get_function_part_constraint (fi, fi_result);
4297 rhs.var = anything_id;
4300 process_constraint (new_constraint (lhs, rhs));
4304 /* printf-style functions may have hooks to set pointers to
4305 point to somewhere into the generated string. Leave them
4306 for a later excercise... */
4308 /* Fallthru to general call handling. */;
4314 /* Create constraints for the call T. */
4317 find_func_aliases_for_call (gimple t)
4319 tree fndecl = gimple_call_fndecl (t);
4320 VEC(ce_s, heap) *lhsc = NULL;
4321 VEC(ce_s, heap) *rhsc = NULL;
4324 if (fndecl != NULL_TREE
4325 && DECL_BUILT_IN (fndecl)
4326 && find_func_aliases_for_builtin_call (t))
4329 fi = get_fi_for_callee (t);
4331 || (fndecl && !fi->is_fn_info))
4333 VEC(ce_s, heap) *rhsc = NULL;
4334 int flags = gimple_call_flags (t);
4336 /* Const functions can return their arguments and addresses
4337 of global memory but not of escaped memory. */
4338 if (flags & (ECF_CONST|ECF_NOVOPS))
4340 if (gimple_call_lhs (t))
4341 handle_const_call (t, &rhsc);
4343 /* Pure functions can return addresses in and of memory
4344 reachable from their arguments, but they are not an escape
4345 point for reachable memory of their arguments. */
4346 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4347 handle_pure_call (t, &rhsc);
4349 handle_rhs_call (t, &rhsc);
4350 if (gimple_call_lhs (t))
4351 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4352 VEC_free (ce_s, heap, rhsc);
4359 /* Assign all the passed arguments to the appropriate incoming
4360 parameters of the function. */
4361 for (j = 0; j < gimple_call_num_args (t); j++)
4363 struct constraint_expr lhs ;
4364 struct constraint_expr *rhsp;
4365 tree arg = gimple_call_arg (t, j);
4367 get_constraint_for_rhs (arg, &rhsc);
4368 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4369 while (VEC_length (ce_s, rhsc) != 0)
4371 rhsp = VEC_last (ce_s, rhsc);
4372 process_constraint (new_constraint (lhs, *rhsp));
4373 VEC_pop (ce_s, rhsc);
4377 /* If we are returning a value, assign it to the result. */
4378 lhsop = gimple_call_lhs (t);
4381 struct constraint_expr rhs;
4382 struct constraint_expr *lhsp;
4384 get_constraint_for (lhsop, &lhsc);
4385 rhs = get_function_part_constraint (fi, fi_result);
4387 && DECL_RESULT (fndecl)
4388 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4390 VEC(ce_s, heap) *tem = NULL;
4391 VEC_safe_push (ce_s, heap, tem, &rhs);
4393 rhs = *VEC_index (ce_s, tem, 0);
4394 VEC_free(ce_s, heap, tem);
4396 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4397 process_constraint (new_constraint (*lhsp, rhs));
4400 /* If we pass the result decl by reference, honor that. */
4403 && DECL_RESULT (fndecl)
4404 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4406 struct constraint_expr lhs;
4407 struct constraint_expr *rhsp;
4409 get_constraint_for_address_of (lhsop, &rhsc);
4410 lhs = get_function_part_constraint (fi, fi_result);
4411 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4412 process_constraint (new_constraint (lhs, *rhsp));
4413 VEC_free (ce_s, heap, rhsc);
4416 /* If we use a static chain, pass it along. */
4417 if (gimple_call_chain (t))
4419 struct constraint_expr lhs;
4420 struct constraint_expr *rhsp;
4422 get_constraint_for (gimple_call_chain (t), &rhsc);
4423 lhs = get_function_part_constraint (fi, fi_static_chain);
4424 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4425 process_constraint (new_constraint (lhs, *rhsp));
4430 /* Walk statement T setting up aliasing constraints according to the
4431 references found in T. This function is the main part of the
4432 constraint builder. AI points to auxiliary alias information used
4433 when building alias sets and computing alias grouping heuristics. */
4436 find_func_aliases (gimple origt)
4439 VEC(ce_s, heap) *lhsc = NULL;
4440 VEC(ce_s, heap) *rhsc = NULL;
4441 struct constraint_expr *c;
4444 /* Now build constraints expressions. */
4445 if (gimple_code (t) == GIMPLE_PHI)
4450 /* For a phi node, assign all the arguments to
4452 get_constraint_for (gimple_phi_result (t), &lhsc);
4453 for (i = 0; i < gimple_phi_num_args (t); i++)
4455 tree strippedrhs = PHI_ARG_DEF (t, i);
4457 STRIP_NOPS (strippedrhs);
4458 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4460 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4462 struct constraint_expr *c2;
4463 while (VEC_length (ce_s, rhsc) > 0)
4465 c2 = VEC_last (ce_s, rhsc);
4466 process_constraint (new_constraint (*c, *c2));
4467 VEC_pop (ce_s, rhsc);
4472 /* In IPA mode, we need to generate constraints to pass call
4473 arguments through their calls. There are two cases,
4474 either a GIMPLE_CALL returning a value, or just a plain
4475 GIMPLE_CALL when we are not.
4477 In non-ipa mode, we need to generate constraints for each
4478 pointer passed by address. */
4479 else if (is_gimple_call (t))
4480 find_func_aliases_for_call (t);
4482 /* Otherwise, just a regular assignment statement. Only care about
4483 operations with pointer result, others are dealt with as escape
4484 points if they have pointer operands. */
4485 else if (is_gimple_assign (t))
4487 /* Otherwise, just a regular assignment statement. */
4488 tree lhsop = gimple_assign_lhs (t);
4489 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4491 if (rhsop && TREE_CLOBBER_P (rhsop))
4492 /* Ignore clobbers, they don't actually store anything into
4495 else if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4496 do_structure_copy (lhsop, rhsop);
4499 enum tree_code code = gimple_assign_rhs_code (t);
4501 get_constraint_for (lhsop, &lhsc);
4503 if (code == POINTER_PLUS_EXPR)
4504 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4505 gimple_assign_rhs2 (t), &rhsc);
4506 else if (code == BIT_AND_EXPR
4507 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4509 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4510 the pointer. Handle it by offsetting it by UNKNOWN. */
4511 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4514 else if ((CONVERT_EXPR_CODE_P (code)
4515 && !(POINTER_TYPE_P (gimple_expr_type (t))
4516 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4517 || gimple_assign_single_p (t))
4518 get_constraint_for_rhs (rhsop, &rhsc);
4519 else if (truth_value_p (code))
4520 /* Truth value results are not pointer (parts). Or at least
4521 very very unreasonable obfuscation of a part. */
4525 /* All other operations are merges. */
4526 VEC (ce_s, heap) *tmp = NULL;
4527 struct constraint_expr *rhsp;
4529 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4530 for (i = 2; i < gimple_num_ops (t); ++i)
4532 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4533 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4534 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4535 VEC_truncate (ce_s, tmp, 0);
4537 VEC_free (ce_s, heap, tmp);
4539 process_all_all_constraints (lhsc, rhsc);
4541 /* If there is a store to a global variable the rhs escapes. */
4542 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4544 && is_global_var (lhsop)
4546 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4547 make_escape_constraint (rhsop);
4549 /* Handle escapes through return. */
4550 else if (gimple_code (t) == GIMPLE_RETURN
4551 && gimple_return_retval (t) != NULL_TREE)
4555 || !(fi = get_vi_for_tree (cfun->decl)))
4556 make_escape_constraint (gimple_return_retval (t));
4557 else if (in_ipa_mode
4560 struct constraint_expr lhs ;
4561 struct constraint_expr *rhsp;
4564 lhs = get_function_part_constraint (fi, fi_result);
4565 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4566 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4567 process_constraint (new_constraint (lhs, *rhsp));
4570 /* Handle asms conservatively by adding escape constraints to everything. */
4571 else if (gimple_code (t) == GIMPLE_ASM)
4573 unsigned i, noutputs;
4574 const char **oconstraints;
4575 const char *constraint;
4576 bool allows_mem, allows_reg, is_inout;
4578 noutputs = gimple_asm_noutputs (t);
4579 oconstraints = XALLOCAVEC (const char *, noutputs);
4581 for (i = 0; i < noutputs; ++i)
4583 tree link = gimple_asm_output_op (t, i);
4584 tree op = TREE_VALUE (link);
4586 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4587 oconstraints[i] = constraint;
4588 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4589 &allows_reg, &is_inout);
4591 /* A memory constraint makes the address of the operand escape. */
4592 if (!allows_reg && allows_mem)
4593 make_escape_constraint (build_fold_addr_expr (op));
4595 /* The asm may read global memory, so outputs may point to
4596 any global memory. */
4599 VEC(ce_s, heap) *lhsc = NULL;
4600 struct constraint_expr rhsc, *lhsp;
4602 get_constraint_for (op, &lhsc);
4603 rhsc.var = nonlocal_id;
4606 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4607 process_constraint (new_constraint (*lhsp, rhsc));
4608 VEC_free (ce_s, heap, lhsc);
4611 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4613 tree link = gimple_asm_input_op (t, i);
4614 tree op = TREE_VALUE (link);
4616 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4618 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4619 &allows_mem, &allows_reg);
4621 /* A memory constraint makes the address of the operand escape. */
4622 if (!allows_reg && allows_mem)
4623 make_escape_constraint (build_fold_addr_expr (op));
4624 /* Strictly we'd only need the constraint to ESCAPED if
4625 the asm clobbers memory, otherwise using something
4626 along the lines of per-call clobbers/uses would be enough. */
4628 make_escape_constraint (op);
4632 VEC_free (ce_s, heap, rhsc);
4633 VEC_free (ce_s, heap, lhsc);
4637 /* Create a constraint adding to the clobber set of FI the memory
4638 pointed to by PTR. */
4641 process_ipa_clobber (varinfo_t fi, tree ptr)
4643 VEC(ce_s, heap) *ptrc = NULL;
4644 struct constraint_expr *c, lhs;
4646 get_constraint_for_rhs (ptr, &ptrc);
4647 lhs = get_function_part_constraint (fi, fi_clobbers);
4648 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4649 process_constraint (new_constraint (lhs, *c));
4650 VEC_free (ce_s, heap, ptrc);
4653 /* Walk statement T setting up clobber and use constraints according to the
4654 references found in T. This function is a main part of the
4655 IPA constraint builder. */
4658 find_func_clobbers (gimple origt)
4661 VEC(ce_s, heap) *lhsc = NULL;
4662 VEC(ce_s, heap) *rhsc = NULL;
4665 /* Add constraints for clobbered/used in IPA mode.
4666 We are not interested in what automatic variables are clobbered
4667 or used as we only use the information in the caller to which
4668 they do not escape. */
4669 gcc_assert (in_ipa_mode);
4671 /* If the stmt refers to memory in any way it better had a VUSE. */
4672 if (gimple_vuse (t) == NULL_TREE)
4675 /* We'd better have function information for the current function. */
4676 fi = lookup_vi_for_tree (cfun->decl);
4677 gcc_assert (fi != NULL);
4679 /* Account for stores in assignments and calls. */
4680 if (gimple_vdef (t) != NULL_TREE
4681 && gimple_has_lhs (t))
4683 tree lhs = gimple_get_lhs (t);
4685 while (handled_component_p (tem))
4686 tem = TREE_OPERAND (tem, 0);
4688 && !auto_var_in_fn_p (tem, cfun->decl))
4689 || INDIRECT_REF_P (tem)
4690 || (TREE_CODE (tem) == MEM_REF
4691 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4693 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4695 struct constraint_expr lhsc, *rhsp;
4697 lhsc = get_function_part_constraint (fi, fi_clobbers);
4698 get_constraint_for_address_of (lhs, &rhsc);
4699 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4700 process_constraint (new_constraint (lhsc, *rhsp));
4701 VEC_free (ce_s, heap, rhsc);
4705 /* Account for uses in assigments and returns. */
4706 if (gimple_assign_single_p (t)
4707 || (gimple_code (t) == GIMPLE_RETURN
4708 && gimple_return_retval (t) != NULL_TREE))
4710 tree rhs = (gimple_assign_single_p (t)
4711 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4713 while (handled_component_p (tem))
4714 tem = TREE_OPERAND (tem, 0);
4716 && !auto_var_in_fn_p (tem, cfun->decl))
4717 || INDIRECT_REF_P (tem)
4718 || (TREE_CODE (tem) == MEM_REF
4719 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4721 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4723 struct constraint_expr lhs, *rhsp;
4725 lhs = get_function_part_constraint (fi, fi_uses);
4726 get_constraint_for_address_of (rhs, &rhsc);
4727 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4728 process_constraint (new_constraint (lhs, *rhsp));
4729 VEC_free (ce_s, heap, rhsc);
4733 if (is_gimple_call (t))
4735 varinfo_t cfi = NULL;
4736 tree decl = gimple_call_fndecl (t);
4737 struct constraint_expr lhs, rhs;
4740 /* For builtins we do not have separate function info. For those
4741 we do not generate escapes for we have to generate clobbers/uses. */
4743 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4744 switch (DECL_FUNCTION_CODE (decl))
4746 /* The following functions use and clobber memory pointed to
4747 by their arguments. */
4748 case BUILT_IN_STRCPY:
4749 case BUILT_IN_STRNCPY:
4750 case BUILT_IN_BCOPY:
4751 case BUILT_IN_MEMCPY:
4752 case BUILT_IN_MEMMOVE:
4753 case BUILT_IN_MEMPCPY:
4754 case BUILT_IN_STPCPY:
4755 case BUILT_IN_STPNCPY:
4756 case BUILT_IN_STRCAT:
4757 case BUILT_IN_STRNCAT:
4758 case BUILT_IN_STRCPY_CHK:
4759 case BUILT_IN_STRNCPY_CHK:
4760 case BUILT_IN_MEMCPY_CHK:
4761 case BUILT_IN_MEMMOVE_CHK:
4762 case BUILT_IN_MEMPCPY_CHK:
4763 case BUILT_IN_STPCPY_CHK:
4764 case BUILT_IN_STPNCPY_CHK:
4765 case BUILT_IN_STRCAT_CHK:
4766 case BUILT_IN_STRNCAT_CHK:
4768 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4769 == BUILT_IN_BCOPY ? 1 : 0));
4770 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4771 == BUILT_IN_BCOPY ? 0 : 1));
4773 struct constraint_expr *rhsp, *lhsp;
4774 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4775 lhs = get_function_part_constraint (fi, fi_clobbers);
4776 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4777 process_constraint (new_constraint (lhs, *lhsp));
4778 VEC_free (ce_s, heap, lhsc);
4779 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4780 lhs = get_function_part_constraint (fi, fi_uses);
4781 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4782 process_constraint (new_constraint (lhs, *rhsp));
4783 VEC_free (ce_s, heap, rhsc);
4786 /* The following function clobbers memory pointed to by
4788 case BUILT_IN_MEMSET:
4789 case BUILT_IN_MEMSET_CHK:
4791 tree dest = gimple_call_arg (t, 0);
4794 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4795 lhs = get_function_part_constraint (fi, fi_clobbers);
4796 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4797 process_constraint (new_constraint (lhs, *lhsp));
4798 VEC_free (ce_s, heap, lhsc);
4801 /* The following functions clobber their second and third
4803 case BUILT_IN_SINCOS:
4804 case BUILT_IN_SINCOSF:
4805 case BUILT_IN_SINCOSL:
4807 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4808 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4811 /* The following functions clobber their second argument. */
4812 case BUILT_IN_FREXP:
4813 case BUILT_IN_FREXPF:
4814 case BUILT_IN_FREXPL:
4815 case BUILT_IN_LGAMMA_R:
4816 case BUILT_IN_LGAMMAF_R:
4817 case BUILT_IN_LGAMMAL_R:
4818 case BUILT_IN_GAMMA_R:
4819 case BUILT_IN_GAMMAF_R:
4820 case BUILT_IN_GAMMAL_R:
4822 case BUILT_IN_MODFF:
4823 case BUILT_IN_MODFL:
4825 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4828 /* The following functions clobber their third argument. */
4829 case BUILT_IN_REMQUO:
4830 case BUILT_IN_REMQUOF:
4831 case BUILT_IN_REMQUOL:
4833 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4836 /* The following functions neither read nor clobber memory. */
4837 case BUILT_IN_ASSUME_ALIGNED:
4840 /* Trampolines are of no interest to us. */
4841 case BUILT_IN_INIT_TRAMPOLINE:
4842 case BUILT_IN_ADJUST_TRAMPOLINE:
4844 case BUILT_IN_VA_START:
4845 case BUILT_IN_VA_END:
4847 /* printf-style functions may have hooks to set pointers to
4848 point to somewhere into the generated string. Leave them
4849 for a later excercise... */
4851 /* Fallthru to general call handling. */;
4854 /* Parameters passed by value are used. */
4855 lhs = get_function_part_constraint (fi, fi_uses);
4856 for (i = 0; i < gimple_call_num_args (t); i++)
4858 struct constraint_expr *rhsp;
4859 tree arg = gimple_call_arg (t, i);
4861 if (TREE_CODE (arg) == SSA_NAME
4862 || is_gimple_min_invariant (arg))
4865 get_constraint_for_address_of (arg, &rhsc);
4866 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4867 process_constraint (new_constraint (lhs, *rhsp));
4868 VEC_free (ce_s, heap, rhsc);
4871 /* Build constraints for propagating clobbers/uses along the
4873 cfi = get_fi_for_callee (t);
4874 if (cfi->id == anything_id)
4876 if (gimple_vdef (t))
4877 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4879 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4884 /* For callees without function info (that's external functions),
4885 ESCAPED is clobbered and used. */
4886 if (gimple_call_fndecl (t)
4887 && !cfi->is_fn_info)
4891 if (gimple_vdef (t))
4892 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4894 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4896 /* Also honor the call statement use/clobber info. */
4897 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4898 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4900 if ((vi = lookup_call_use_vi (t)) != NULL)
4901 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4906 /* Otherwise the caller clobbers and uses what the callee does.
4907 ??? This should use a new complex constraint that filters
4908 local variables of the callee. */
4909 if (gimple_vdef (t))
4911 lhs = get_function_part_constraint (fi, fi_clobbers);
4912 rhs = get_function_part_constraint (cfi, fi_clobbers);
4913 process_constraint (new_constraint (lhs, rhs));
4915 lhs = get_function_part_constraint (fi, fi_uses);
4916 rhs = get_function_part_constraint (cfi, fi_uses);
4917 process_constraint (new_constraint (lhs, rhs));
4919 else if (gimple_code (t) == GIMPLE_ASM)
4921 /* ??? Ick. We can do better. */
4922 if (gimple_vdef (t))
4923 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4925 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4929 VEC_free (ce_s, heap, rhsc);
4933 /* Find the first varinfo in the same variable as START that overlaps with
4934 OFFSET. Return NULL if we can't find one. */
4937 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4939 /* If the offset is outside of the variable, bail out. */
4940 if (offset >= start->fullsize)
4943 /* If we cannot reach offset from start, lookup the first field
4944 and start from there. */
4945 if (start->offset > offset)
4946 start = lookup_vi_for_tree (start->decl);
4950 /* We may not find a variable in the field list with the actual
4951 offset when when we have glommed a structure to a variable.
4952 In that case, however, offset should still be within the size
4954 if (offset >= start->offset
4955 && (offset - start->offset) < start->size)
4964 /* Find the first varinfo in the same variable as START that overlaps with
4965 OFFSET. If there is no such varinfo the varinfo directly preceding
4966 OFFSET is returned. */
4969 first_or_preceding_vi_for_offset (varinfo_t start,
4970 unsigned HOST_WIDE_INT offset)
4972 /* If we cannot reach offset from start, lookup the first field
4973 and start from there. */
4974 if (start->offset > offset)
4975 start = lookup_vi_for_tree (start->decl);
4977 /* We may not find a variable in the field list with the actual
4978 offset when when we have glommed a structure to a variable.
4979 In that case, however, offset should still be within the size
4981 If we got beyond the offset we look for return the field
4982 directly preceding offset which may be the last field. */
4984 && offset >= start->offset
4985 && !((offset - start->offset) < start->size))
4986 start = start->next;
4992 /* This structure is used during pushing fields onto the fieldstack
4993 to track the offset of the field, since bitpos_of_field gives it
4994 relative to its immediate containing type, and we want it relative
4995 to the ultimate containing object. */
4999 /* Offset from the base of the base containing object to this field. */
5000 HOST_WIDE_INT offset;
5002 /* Size, in bits, of the field. */
5003 unsigned HOST_WIDE_INT size;
5005 unsigned has_unknown_size : 1;
5007 unsigned must_have_pointers : 1;
5009 unsigned may_have_pointers : 1;
5011 unsigned only_restrict_pointers : 1;
5013 typedef struct fieldoff fieldoff_s;
5015 DEF_VEC_O(fieldoff_s);
5016 DEF_VEC_ALLOC_O(fieldoff_s,heap);
5018 /* qsort comparison function for two fieldoff's PA and PB */
5021 fieldoff_compare (const void *pa, const void *pb)
5023 const fieldoff_s *foa = (const fieldoff_s *)pa;
5024 const fieldoff_s *fob = (const fieldoff_s *)pb;
5025 unsigned HOST_WIDE_INT foasize, fobsize;
5027 if (foa->offset < fob->offset)
5029 else if (foa->offset > fob->offset)
5032 foasize = foa->size;
5033 fobsize = fob->size;
5034 if (foasize < fobsize)
5036 else if (foasize > fobsize)
5041 /* Sort a fieldstack according to the field offset and sizes. */
5043 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
5045 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
5048 /* Return true if T is a type that can have subvars. */
5051 type_can_have_subvars (const_tree t)
5053 /* Aggregates without overlapping fields can have subvars. */
5054 return TREE_CODE (t) == RECORD_TYPE;
5057 /* Return true if V is a tree that we can have subvars for.
5058 Normally, this is any aggregate type. Also complex
5059 types which are not gimple registers can have subvars. */
5062 var_can_have_subvars (const_tree v)
5064 /* Volatile variables should never have subvars. */
5065 if (TREE_THIS_VOLATILE (v))
5068 /* Non decls or memory tags can never have subvars. */
5072 return type_can_have_subvars (TREE_TYPE (v));
5075 /* Return true if T is a type that does contain pointers. */
5078 type_must_have_pointers (tree type)
5080 if (POINTER_TYPE_P (type))
5083 if (TREE_CODE (type) == ARRAY_TYPE)
5084 return type_must_have_pointers (TREE_TYPE (type));
5086 /* A function or method can have pointers as arguments, so track
5087 those separately. */
5088 if (TREE_CODE (type) == FUNCTION_TYPE
5089 || TREE_CODE (type) == METHOD_TYPE)
5096 field_must_have_pointers (tree t)
5098 return type_must_have_pointers (TREE_TYPE (t));
5101 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5102 the fields of TYPE onto fieldstack, recording their offsets along
5105 OFFSET is used to keep track of the offset in this entire
5106 structure, rather than just the immediately containing structure.
5107 Returns false if the caller is supposed to handle the field we
5111 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5112 HOST_WIDE_INT offset)
5115 bool empty_p = true;
5117 if (TREE_CODE (type) != RECORD_TYPE)
5120 /* If the vector of fields is growing too big, bail out early.
5121 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5123 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5126 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5127 if (TREE_CODE (field) == FIELD_DECL)
5130 HOST_WIDE_INT foff = bitpos_of_field (field);
5132 if (!var_can_have_subvars (field)
5133 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5134 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5136 else if (!push_fields_onto_fieldstack
5137 (TREE_TYPE (field), fieldstack, offset + foff)
5138 && (DECL_SIZE (field)
5139 && !integer_zerop (DECL_SIZE (field))))
5140 /* Empty structures may have actual size, like in C++. So
5141 see if we didn't push any subfields and the size is
5142 nonzero, push the field onto the stack. */
5147 fieldoff_s *pair = NULL;
5148 bool has_unknown_size = false;
5149 bool must_have_pointers_p;
5151 if (!VEC_empty (fieldoff_s, *fieldstack))
5152 pair = VEC_last (fieldoff_s, *fieldstack);
5154 /* If there isn't anything at offset zero, create sth. */
5156 && offset + foff != 0)
5158 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5160 pair->size = offset + foff;
5161 pair->has_unknown_size = false;
5162 pair->must_have_pointers = false;
5163 pair->may_have_pointers = false;
5164 pair->only_restrict_pointers = false;
5167 if (!DECL_SIZE (field)
5168 || !host_integerp (DECL_SIZE (field), 1))
5169 has_unknown_size = true;
5171 /* If adjacent fields do not contain pointers merge them. */
5172 must_have_pointers_p = field_must_have_pointers (field);
5174 && !has_unknown_size
5175 && !must_have_pointers_p
5176 && !pair->must_have_pointers
5177 && !pair->has_unknown_size
5178 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5180 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5184 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5185 pair->offset = offset + foff;
5186 pair->has_unknown_size = has_unknown_size;
5187 if (!has_unknown_size)
5188 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5191 pair->must_have_pointers = must_have_pointers_p;
5192 pair->may_have_pointers = true;
5193 pair->only_restrict_pointers
5194 = (!has_unknown_size
5195 && POINTER_TYPE_P (TREE_TYPE (field))
5196 && TYPE_RESTRICT (TREE_TYPE (field)));
5206 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5207 if it is a varargs function. */
5210 count_num_arguments (tree decl, bool *is_varargs)
5212 unsigned int num = 0;
5215 /* Capture named arguments for K&R functions. They do not
5216 have a prototype and thus no TYPE_ARG_TYPES. */
5217 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5220 /* Check if the function has variadic arguments. */
5221 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5222 if (TREE_VALUE (t) == void_type_node)
5230 /* Creation function node for DECL, using NAME, and return the index
5231 of the variable we've created for the function. */
5234 create_function_info_for (tree decl, const char *name)
5236 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5237 varinfo_t vi, prev_vi;
5240 bool is_varargs = false;
5241 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5243 /* Create the variable info. */
5245 vi = new_var_info (decl, name);
5248 vi->fullsize = fi_parm_base + num_args;
5250 vi->may_have_pointers = false;
5253 insert_vi_for_tree (vi->decl, vi);
5257 /* Create a variable for things the function clobbers and one for
5258 things the function uses. */
5260 varinfo_t clobbervi, usevi;
5261 const char *newname;
5264 asprintf (&tempname, "%s.clobber", name);
5265 newname = ggc_strdup (tempname);
5268 clobbervi = new_var_info (NULL, newname);
5269 clobbervi->offset = fi_clobbers;
5270 clobbervi->size = 1;
5271 clobbervi->fullsize = vi->fullsize;
5272 clobbervi->is_full_var = true;
5273 clobbervi->is_global_var = false;
5274 gcc_assert (prev_vi->offset < clobbervi->offset);
5275 prev_vi->next = clobbervi;
5276 prev_vi = clobbervi;
5278 asprintf (&tempname, "%s.use", name);
5279 newname = ggc_strdup (tempname);
5282 usevi = new_var_info (NULL, newname);
5283 usevi->offset = fi_uses;
5285 usevi->fullsize = vi->fullsize;
5286 usevi->is_full_var = true;
5287 usevi->is_global_var = false;
5288 gcc_assert (prev_vi->offset < usevi->offset);
5289 prev_vi->next = usevi;
5293 /* And one for the static chain. */
5294 if (fn->static_chain_decl != NULL_TREE)
5297 const char *newname;
5300 asprintf (&tempname, "%s.chain", name);
5301 newname = ggc_strdup (tempname);
5304 chainvi = new_var_info (fn->static_chain_decl, newname);
5305 chainvi->offset = fi_static_chain;
5307 chainvi->fullsize = vi->fullsize;
5308 chainvi->is_full_var = true;
5309 chainvi->is_global_var = false;
5310 gcc_assert (prev_vi->offset < chainvi->offset);
5311 prev_vi->next = chainvi;
5313 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5316 /* Create a variable for the return var. */
5317 if (DECL_RESULT (decl) != NULL
5318 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5321 const char *newname;
5323 tree resultdecl = decl;
5325 if (DECL_RESULT (decl))
5326 resultdecl = DECL_RESULT (decl);
5328 asprintf (&tempname, "%s.result", name);
5329 newname = ggc_strdup (tempname);
5332 resultvi = new_var_info (resultdecl, newname);
5333 resultvi->offset = fi_result;
5335 resultvi->fullsize = vi->fullsize;
5336 resultvi->is_full_var = true;
5337 if (DECL_RESULT (decl))
5338 resultvi->may_have_pointers = true;
5339 gcc_assert (prev_vi->offset < resultvi->offset);
5340 prev_vi->next = resultvi;
5342 if (DECL_RESULT (decl))
5343 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5346 /* Set up variables for each argument. */
5347 arg = DECL_ARGUMENTS (decl);
5348 for (i = 0; i < num_args; i++)
5351 const char *newname;
5353 tree argdecl = decl;
5358 asprintf (&tempname, "%s.arg%d", name, i);
5359 newname = ggc_strdup (tempname);
5362 argvi = new_var_info (argdecl, newname);
5363 argvi->offset = fi_parm_base + i;
5365 argvi->is_full_var = true;
5366 argvi->fullsize = vi->fullsize;
5368 argvi->may_have_pointers = true;
5369 gcc_assert (prev_vi->offset < argvi->offset);
5370 prev_vi->next = argvi;
5374 insert_vi_for_tree (arg, argvi);
5375 arg = DECL_CHAIN (arg);
5379 /* Add one representative for all further args. */
5383 const char *newname;
5387 asprintf (&tempname, "%s.varargs", name);
5388 newname = ggc_strdup (tempname);
5391 /* We need sth that can be pointed to for va_start. */
5392 decl = build_fake_var_decl (ptr_type_node);
5394 argvi = new_var_info (decl, newname);
5395 argvi->offset = fi_parm_base + num_args;
5397 argvi->is_full_var = true;
5398 argvi->is_heap_var = true;
5399 argvi->fullsize = vi->fullsize;
5400 gcc_assert (prev_vi->offset < argvi->offset);
5401 prev_vi->next = argvi;
5409 /* Return true if FIELDSTACK contains fields that overlap.
5410 FIELDSTACK is assumed to be sorted by offset. */
5413 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5415 fieldoff_s *fo = NULL;
5417 HOST_WIDE_INT lastoffset = -1;
5419 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5421 if (fo->offset == lastoffset)
5423 lastoffset = fo->offset;
5428 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5429 This will also create any varinfo structures necessary for fields
5433 create_variable_info_for_1 (tree decl, const char *name)
5435 varinfo_t vi, newvi;
5436 tree decl_type = TREE_TYPE (decl);
5437 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5438 VEC (fieldoff_s,heap) *fieldstack = NULL;
5443 || !host_integerp (declsize, 1))
5445 vi = new_var_info (decl, name);
5449 vi->is_unknown_size_var = true;
5450 vi->is_full_var = true;
5451 vi->may_have_pointers = true;
5455 /* Collect field information. */
5456 if (use_field_sensitive
5457 && var_can_have_subvars (decl)
5458 /* ??? Force us to not use subfields for global initializers
5459 in IPA mode. Else we'd have to parse arbitrary initializers. */
5461 && is_global_var (decl)
5462 && DECL_INITIAL (decl)))
5464 fieldoff_s *fo = NULL;
5465 bool notokay = false;
5468 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5470 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5471 if (fo->has_unknown_size
5478 /* We can't sort them if we have a field with a variable sized type,
5479 which will make notokay = true. In that case, we are going to return
5480 without creating varinfos for the fields anyway, so sorting them is a
5484 sort_fieldstack (fieldstack);
5485 /* Due to some C++ FE issues, like PR 22488, we might end up
5486 what appear to be overlapping fields even though they,
5487 in reality, do not overlap. Until the C++ FE is fixed,
5488 we will simply disable field-sensitivity for these cases. */
5489 notokay = check_for_overlaps (fieldstack);
5493 VEC_free (fieldoff_s, heap, fieldstack);
5496 /* If we didn't end up collecting sub-variables create a full
5497 variable for the decl. */
5498 if (VEC_length (fieldoff_s, fieldstack) <= 1
5499 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5501 vi = new_var_info (decl, name);
5503 vi->may_have_pointers = true;
5504 vi->fullsize = TREE_INT_CST_LOW (declsize);
5505 vi->size = vi->fullsize;
5506 vi->is_full_var = true;
5507 VEC_free (fieldoff_s, heap, fieldstack);
5511 vi = new_var_info (decl, name);
5512 vi->fullsize = TREE_INT_CST_LOW (declsize);
5513 for (i = 0, newvi = vi;
5514 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5515 ++i, newvi = newvi->next)
5517 const char *newname = "NULL";
5522 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5523 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5524 newname = ggc_strdup (tempname);
5527 newvi->name = newname;
5528 newvi->offset = fo->offset;
5529 newvi->size = fo->size;
5530 newvi->fullsize = vi->fullsize;
5531 newvi->may_have_pointers = fo->may_have_pointers;
5532 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5533 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5534 newvi->next = new_var_info (decl, name);
5537 VEC_free (fieldoff_s, heap, fieldstack);
5543 create_variable_info_for (tree decl, const char *name)
5545 varinfo_t vi = create_variable_info_for_1 (decl, name);
5546 unsigned int id = vi->id;
5548 insert_vi_for_tree (decl, vi);
5550 if (TREE_CODE (decl) != VAR_DECL)
5553 /* Create initial constraints for globals. */
5554 for (; vi; vi = vi->next)
5556 if (!vi->may_have_pointers
5557 || !vi->is_global_var)
5560 /* Mark global restrict qualified pointers. */
5561 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5562 && TYPE_RESTRICT (TREE_TYPE (decl)))
5563 || vi->only_restrict_pointers)
5565 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
5569 /* In non-IPA mode the initializer from nonlocal is all we need. */
5571 || DECL_HARD_REGISTER (decl))
5572 make_copy_constraint (vi, nonlocal_id);
5574 /* In IPA mode parse the initializer and generate proper constraints
5578 struct varpool_node *vnode = varpool_get_node (decl);
5580 /* For escaped variables initialize them from nonlocal. */
5581 if (!varpool_all_refs_explicit_p (vnode))
5582 make_copy_constraint (vi, nonlocal_id);
5584 /* If this is a global variable with an initializer and we are in
5585 IPA mode generate constraints for it. */
5586 if (DECL_INITIAL (decl))
5588 VEC (ce_s, heap) *rhsc = NULL;
5589 struct constraint_expr lhs, *rhsp;
5591 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5595 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5596 process_constraint (new_constraint (lhs, *rhsp));
5597 /* If this is a variable that escapes from the unit
5598 the initializer escapes as well. */
5599 if (!varpool_all_refs_explicit_p (vnode))
5601 lhs.var = escaped_id;
5604 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5605 process_constraint (new_constraint (lhs, *rhsp));
5607 VEC_free (ce_s, heap, rhsc);
5615 /* Print out the points-to solution for VAR to FILE. */
5618 dump_solution_for_var (FILE *file, unsigned int var)
5620 varinfo_t vi = get_varinfo (var);
5624 /* Dump the solution for unified vars anyway, this avoids difficulties
5625 in scanning dumps in the testsuite. */
5626 fprintf (file, "%s = { ", vi->name);
5627 vi = get_varinfo (find (var));
5628 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5629 fprintf (file, "%s ", get_varinfo (i)->name);
5630 fprintf (file, "}");
5632 /* But note when the variable was unified. */
5634 fprintf (file, " same as %s", vi->name);
5636 fprintf (file, "\n");
5639 /* Print the points-to solution for VAR to stdout. */
5642 debug_solution_for_var (unsigned int var)
5644 dump_solution_for_var (stdout, var);
5647 /* Create varinfo structures for all of the variables in the
5648 function for intraprocedural mode. */
5651 intra_create_variable_infos (void)
5655 /* For each incoming pointer argument arg, create the constraint ARG
5656 = NONLOCAL or a dummy variable if it is a restrict qualified
5657 passed-by-reference argument. */
5658 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5660 varinfo_t p = get_vi_for_tree (t);
5662 /* For restrict qualified pointers to objects passed by
5663 reference build a real representative for the pointed-to object.
5664 Treat restrict qualified references the same. */
5665 if (TYPE_RESTRICT (TREE_TYPE (t))
5666 && ((DECL_BY_REFERENCE (t) && POINTER_TYPE_P (TREE_TYPE (t)))
5667 || TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE))
5669 struct constraint_expr lhsc, rhsc;
5671 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t)));
5672 DECL_EXTERNAL (heapvar) = 1;
5673 vi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS");
5674 insert_vi_for_tree (heapvar, vi);
5679 rhsc.type = ADDRESSOF;
5681 process_constraint (new_constraint (lhsc, rhsc));
5682 for (; vi; vi = vi->next)
5683 if (vi->may_have_pointers)
5685 if (vi->only_restrict_pointers)
5686 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
5688 make_copy_constraint (vi, nonlocal_id);
5693 if (POINTER_TYPE_P (TREE_TYPE (t))
5694 && TYPE_RESTRICT (TREE_TYPE (t)))
5695 make_constraint_from_global_restrict (p, "PARM_RESTRICT");
5698 for (; p; p = p->next)
5700 if (p->only_restrict_pointers)
5701 make_constraint_from_global_restrict (p, "PARM_RESTRICT");
5702 else if (p->may_have_pointers)
5703 make_constraint_from (p, nonlocal_id);
5708 /* Add a constraint for a result decl that is passed by reference. */
5709 if (DECL_RESULT (cfun->decl)
5710 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5712 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5714 for (p = result_vi; p; p = p->next)
5715 make_constraint_from (p, nonlocal_id);
5718 /* Add a constraint for the incoming static chain parameter. */
5719 if (cfun->static_chain_decl != NULL_TREE)
5721 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5723 for (p = chain_vi; p; p = p->next)
5724 make_constraint_from (p, nonlocal_id);
5728 /* Structure used to put solution bitmaps in a hashtable so they can
5729 be shared among variables with the same points-to set. */
5731 typedef struct shared_bitmap_info
5735 } *shared_bitmap_info_t;
5736 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5738 static htab_t shared_bitmap_table;
5740 /* Hash function for a shared_bitmap_info_t */
5743 shared_bitmap_hash (const void *p)
5745 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5746 return bi->hashcode;
5749 /* Equality function for two shared_bitmap_info_t's. */
5752 shared_bitmap_eq (const void *p1, const void *p2)
5754 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5755 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5756 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5759 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5760 existing instance if there is one, NULL otherwise. */
5763 shared_bitmap_lookup (bitmap pt_vars)
5766 struct shared_bitmap_info sbi;
5768 sbi.pt_vars = pt_vars;
5769 sbi.hashcode = bitmap_hash (pt_vars);
5771 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5772 sbi.hashcode, NO_INSERT);
5776 return ((shared_bitmap_info_t) *slot)->pt_vars;
5780 /* Add a bitmap to the shared bitmap hashtable. */
5783 shared_bitmap_add (bitmap pt_vars)
5786 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5788 sbi->pt_vars = pt_vars;
5789 sbi->hashcode = bitmap_hash (pt_vars);
5791 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5792 sbi->hashcode, INSERT);
5793 gcc_assert (!*slot);
5794 *slot = (void *) sbi;
5798 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5801 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5806 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5808 varinfo_t vi = get_varinfo (i);
5810 /* The only artificial variables that are allowed in a may-alias
5811 set are heap variables. */
5812 if (vi->is_artificial_var && !vi->is_heap_var)
5815 if (TREE_CODE (vi->decl) == VAR_DECL
5816 || TREE_CODE (vi->decl) == PARM_DECL
5817 || TREE_CODE (vi->decl) == RESULT_DECL)
5819 /* If we are in IPA mode we will not recompute points-to
5820 sets after inlining so make sure they stay valid. */
5822 && !DECL_PT_UID_SET_P (vi->decl))
5823 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5825 /* Add the decl to the points-to set. Note that the points-to
5826 set contains global variables. */
5827 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5828 if (vi->is_global_var)
5829 pt->vars_contains_global = true;
5835 /* Compute the points-to solution *PT for the variable VI. */
5838 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5842 bitmap finished_solution;
5846 memset (pt, 0, sizeof (struct pt_solution));
5848 /* This variable may have been collapsed, let's get the real
5850 vi = get_varinfo (find (orig_vi->id));
5852 /* Translate artificial variables into SSA_NAME_PTR_INFO
5854 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5856 varinfo_t vi = get_varinfo (i);
5858 if (vi->is_artificial_var)
5860 if (vi->id == nothing_id)
5862 else if (vi->id == escaped_id)
5865 pt->ipa_escaped = 1;
5869 else if (vi->id == nonlocal_id)
5871 else if (vi->is_heap_var)
5872 /* We represent heapvars in the points-to set properly. */
5874 else if (vi->id == readonly_id)
5877 else if (vi->id == anything_id
5878 || vi->id == integer_id)
5883 /* Instead of doing extra work, simply do not create
5884 elaborate points-to information for pt_anything pointers. */
5888 /* Share the final set of variables when possible. */
5889 finished_solution = BITMAP_GGC_ALLOC ();
5890 stats.points_to_sets_created++;
5892 set_uids_in_ptset (finished_solution, vi->solution, pt);
5893 result = shared_bitmap_lookup (finished_solution);
5896 shared_bitmap_add (finished_solution);
5897 pt->vars = finished_solution;
5902 bitmap_clear (finished_solution);
5906 /* Given a pointer variable P, fill in its points-to set. */
5909 find_what_p_points_to (tree p)
5911 struct ptr_info_def *pi;
5915 /* For parameters, get at the points-to set for the actual parm
5917 if (TREE_CODE (p) == SSA_NAME
5918 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5919 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5920 && SSA_NAME_IS_DEFAULT_DEF (p))
5921 lookup_p = SSA_NAME_VAR (p);
5923 vi = lookup_vi_for_tree (lookup_p);
5927 pi = get_ptr_info (p);
5928 find_what_var_points_to (vi, &pi->pt);
5932 /* Query statistics for points-to solutions. */
5935 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5936 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5937 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5938 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5942 dump_pta_stats (FILE *s)
5944 fprintf (s, "\nPTA query stats:\n");
5945 fprintf (s, " pt_solution_includes: "
5946 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5947 HOST_WIDE_INT_PRINT_DEC" queries\n",
5948 pta_stats.pt_solution_includes_no_alias,
5949 pta_stats.pt_solution_includes_no_alias
5950 + pta_stats.pt_solution_includes_may_alias);
5951 fprintf (s, " pt_solutions_intersect: "
5952 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5953 HOST_WIDE_INT_PRINT_DEC" queries\n",
5954 pta_stats.pt_solutions_intersect_no_alias,
5955 pta_stats.pt_solutions_intersect_no_alias
5956 + pta_stats.pt_solutions_intersect_may_alias);
5960 /* Reset the points-to solution *PT to a conservative default
5961 (point to anything). */
5964 pt_solution_reset (struct pt_solution *pt)
5966 memset (pt, 0, sizeof (struct pt_solution));
5967 pt->anything = true;
5970 /* Set the points-to solution *PT to point only to the variables
5971 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5972 global variables and VARS_CONTAINS_RESTRICT specifies whether
5973 it contains restrict tag variables. */
5976 pt_solution_set (struct pt_solution *pt, bitmap vars, bool vars_contains_global)
5978 memset (pt, 0, sizeof (struct pt_solution));
5980 pt->vars_contains_global = vars_contains_global;
5983 /* Set the points-to solution *PT to point only to the variable VAR. */
5986 pt_solution_set_var (struct pt_solution *pt, tree var)
5988 memset (pt, 0, sizeof (struct pt_solution));
5989 pt->vars = BITMAP_GGC_ALLOC ();
5990 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5991 pt->vars_contains_global = is_global_var (var);
5994 /* Computes the union of the points-to solutions *DEST and *SRC and
5995 stores the result in *DEST. This changes the points-to bitmap
5996 of *DEST and thus may not be used if that might be shared.
5997 The points-to bitmap of *SRC and *DEST will not be shared after
5998 this function if they were not before. */
6001 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
6003 dest->anything |= src->anything;
6006 pt_solution_reset (dest);
6010 dest->nonlocal |= src->nonlocal;
6011 dest->escaped |= src->escaped;
6012 dest->ipa_escaped |= src->ipa_escaped;
6013 dest->null |= src->null;
6014 dest->vars_contains_global |= src->vars_contains_global;
6019 dest->vars = BITMAP_GGC_ALLOC ();
6020 bitmap_ior_into (dest->vars, src->vars);
6023 /* Return true if the points-to solution *PT is empty. */
6026 pt_solution_empty_p (struct pt_solution *pt)
6033 && !bitmap_empty_p (pt->vars))
6036 /* If the solution includes ESCAPED, check if that is empty. */
6038 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6041 /* If the solution includes ESCAPED, check if that is empty. */
6043 && !pt_solution_empty_p (&ipa_escaped_pt))
6049 /* Return true if the points-to solution *PT only point to a single var, and
6050 return the var uid in *UID. */
6053 pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid)
6055 if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped
6056 || pt->null || pt->vars == NULL
6057 || !bitmap_single_bit_set_p (pt->vars))
6060 *uid = bitmap_first_set_bit (pt->vars);
6064 /* Return true if the points-to solution *PT includes global memory. */
6067 pt_solution_includes_global (struct pt_solution *pt)
6071 || pt->vars_contains_global)
6075 return pt_solution_includes_global (&cfun->gimple_df->escaped);
6077 if (pt->ipa_escaped)
6078 return pt_solution_includes_global (&ipa_escaped_pt);
6080 /* ??? This predicate is not correct for the IPA-PTA solution
6081 as we do not properly distinguish between unit escape points
6082 and global variables. */
6083 if (cfun->gimple_df->ipa_pta)
6089 /* Return true if the points-to solution *PT includes the variable
6090 declaration DECL. */
6093 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
6099 && is_global_var (decl))
6103 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
6106 /* If the solution includes ESCAPED, check it. */
6108 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
6111 /* If the solution includes ESCAPED, check it. */
6113 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6120 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6122 bool res = pt_solution_includes_1 (pt, decl);
6124 ++pta_stats.pt_solution_includes_may_alias;
6126 ++pta_stats.pt_solution_includes_no_alias;
6130 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6134 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6136 if (pt1->anything || pt2->anything)
6139 /* If either points to unknown global memory and the other points to
6140 any global memory they alias. */
6143 || pt2->vars_contains_global))
6145 && pt1->vars_contains_global))
6148 /* Check the escaped solution if required. */
6149 if ((pt1->escaped || pt2->escaped)
6150 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6152 /* If both point to escaped memory and that solution
6153 is not empty they alias. */
6154 if (pt1->escaped && pt2->escaped)
6157 /* If either points to escaped memory see if the escaped solution
6158 intersects with the other. */
6160 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6162 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6166 /* Check the escaped solution if required.
6167 ??? Do we need to check the local against the IPA escaped sets? */
6168 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6169 && !pt_solution_empty_p (&ipa_escaped_pt))
6171 /* If both point to escaped memory and that solution
6172 is not empty they alias. */
6173 if (pt1->ipa_escaped && pt2->ipa_escaped)
6176 /* If either points to escaped memory see if the escaped solution
6177 intersects with the other. */
6178 if ((pt1->ipa_escaped
6179 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6180 || (pt2->ipa_escaped
6181 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6185 /* Now both pointers alias if their points-to solution intersects. */
6188 && bitmap_intersect_p (pt1->vars, pt2->vars));
6192 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6194 bool res = pt_solutions_intersect_1 (pt1, pt2);
6196 ++pta_stats.pt_solutions_intersect_may_alias;
6198 ++pta_stats.pt_solutions_intersect_no_alias;
6203 /* Dump points-to information to OUTFILE. */
6206 dump_sa_points_to_info (FILE *outfile)
6210 fprintf (outfile, "\nPoints-to sets\n\n");
6212 if (dump_flags & TDF_STATS)
6214 fprintf (outfile, "Stats:\n");
6215 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6216 fprintf (outfile, "Non-pointer vars: %d\n",
6217 stats.nonpointer_vars);
6218 fprintf (outfile, "Statically unified vars: %d\n",
6219 stats.unified_vars_static);
6220 fprintf (outfile, "Dynamically unified vars: %d\n",
6221 stats.unified_vars_dynamic);
6222 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6223 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6224 fprintf (outfile, "Number of implicit edges: %d\n",
6225 stats.num_implicit_edges);
6228 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6230 varinfo_t vi = get_varinfo (i);
6231 if (!vi->may_have_pointers)
6233 dump_solution_for_var (outfile, i);
6238 /* Debug points-to information to stderr. */
6241 debug_sa_points_to_info (void)
6243 dump_sa_points_to_info (stderr);
6247 /* Initialize the always-existing constraint variables for NULL
6248 ANYTHING, READONLY, and INTEGER */
6251 init_base_vars (void)
6253 struct constraint_expr lhs, rhs;
6254 varinfo_t var_anything;
6255 varinfo_t var_nothing;
6256 varinfo_t var_readonly;
6257 varinfo_t var_escaped;
6258 varinfo_t var_nonlocal;
6259 varinfo_t var_storedanything;
6260 varinfo_t var_integer;
6262 /* Create the NULL variable, used to represent that a variable points
6264 var_nothing = new_var_info (NULL_TREE, "NULL");
6265 gcc_assert (var_nothing->id == nothing_id);
6266 var_nothing->is_artificial_var = 1;
6267 var_nothing->offset = 0;
6268 var_nothing->size = ~0;
6269 var_nothing->fullsize = ~0;
6270 var_nothing->is_special_var = 1;
6271 var_nothing->may_have_pointers = 0;
6272 var_nothing->is_global_var = 0;
6274 /* Create the ANYTHING variable, used to represent that a variable
6275 points to some unknown piece of memory. */
6276 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6277 gcc_assert (var_anything->id == anything_id);
6278 var_anything->is_artificial_var = 1;
6279 var_anything->size = ~0;
6280 var_anything->offset = 0;
6281 var_anything->next = NULL;
6282 var_anything->fullsize = ~0;
6283 var_anything->is_special_var = 1;
6285 /* Anything points to anything. This makes deref constraints just
6286 work in the presence of linked list and other p = *p type loops,
6287 by saying that *ANYTHING = ANYTHING. */
6289 lhs.var = anything_id;
6291 rhs.type = ADDRESSOF;
6292 rhs.var = anything_id;
6295 /* This specifically does not use process_constraint because
6296 process_constraint ignores all anything = anything constraints, since all
6297 but this one are redundant. */
6298 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6300 /* Create the READONLY variable, used to represent that a variable
6301 points to readonly memory. */
6302 var_readonly = new_var_info (NULL_TREE, "READONLY");
6303 gcc_assert (var_readonly->id == readonly_id);
6304 var_readonly->is_artificial_var = 1;
6305 var_readonly->offset = 0;
6306 var_readonly->size = ~0;
6307 var_readonly->fullsize = ~0;
6308 var_readonly->next = NULL;
6309 var_readonly->is_special_var = 1;
6311 /* readonly memory points to anything, in order to make deref
6312 easier. In reality, it points to anything the particular
6313 readonly variable can point to, but we don't track this
6316 lhs.var = readonly_id;
6318 rhs.type = ADDRESSOF;
6319 rhs.var = readonly_id; /* FIXME */
6321 process_constraint (new_constraint (lhs, rhs));
6323 /* Create the ESCAPED variable, used to represent the set of escaped
6325 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6326 gcc_assert (var_escaped->id == escaped_id);
6327 var_escaped->is_artificial_var = 1;
6328 var_escaped->offset = 0;
6329 var_escaped->size = ~0;
6330 var_escaped->fullsize = ~0;
6331 var_escaped->is_special_var = 0;
6333 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6335 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6336 gcc_assert (var_nonlocal->id == nonlocal_id);
6337 var_nonlocal->is_artificial_var = 1;
6338 var_nonlocal->offset = 0;
6339 var_nonlocal->size = ~0;
6340 var_nonlocal->fullsize = ~0;
6341 var_nonlocal->is_special_var = 1;
6343 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6345 lhs.var = escaped_id;
6348 rhs.var = escaped_id;
6350 process_constraint (new_constraint (lhs, rhs));
6352 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6353 whole variable escapes. */
6355 lhs.var = escaped_id;
6358 rhs.var = escaped_id;
6359 rhs.offset = UNKNOWN_OFFSET;
6360 process_constraint (new_constraint (lhs, rhs));
6362 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6363 everything pointed to by escaped points to what global memory can
6366 lhs.var = escaped_id;
6369 rhs.var = nonlocal_id;
6371 process_constraint (new_constraint (lhs, rhs));
6373 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6374 global memory may point to global memory and escaped memory. */
6376 lhs.var = nonlocal_id;
6378 rhs.type = ADDRESSOF;
6379 rhs.var = nonlocal_id;
6381 process_constraint (new_constraint (lhs, rhs));
6382 rhs.type = ADDRESSOF;
6383 rhs.var = escaped_id;
6385 process_constraint (new_constraint (lhs, rhs));
6387 /* Create the STOREDANYTHING variable, used to represent the set of
6388 variables stored to *ANYTHING. */
6389 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6390 gcc_assert (var_storedanything->id == storedanything_id);
6391 var_storedanything->is_artificial_var = 1;
6392 var_storedanything->offset = 0;
6393 var_storedanything->size = ~0;
6394 var_storedanything->fullsize = ~0;
6395 var_storedanything->is_special_var = 0;
6397 /* Create the INTEGER variable, used to represent that a variable points
6398 to what an INTEGER "points to". */
6399 var_integer = new_var_info (NULL_TREE, "INTEGER");
6400 gcc_assert (var_integer->id == integer_id);
6401 var_integer->is_artificial_var = 1;
6402 var_integer->size = ~0;
6403 var_integer->fullsize = ~0;
6404 var_integer->offset = 0;
6405 var_integer->next = NULL;
6406 var_integer->is_special_var = 1;
6408 /* INTEGER = ANYTHING, because we don't know where a dereference of
6409 a random integer will point to. */
6411 lhs.var = integer_id;
6413 rhs.type = ADDRESSOF;
6414 rhs.var = anything_id;
6416 process_constraint (new_constraint (lhs, rhs));
6419 /* Initialize things necessary to perform PTA */
6422 init_alias_vars (void)
6424 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6426 bitmap_obstack_initialize (&pta_obstack);
6427 bitmap_obstack_initialize (&oldpta_obstack);
6428 bitmap_obstack_initialize (&predbitmap_obstack);
6430 constraint_pool = create_alloc_pool ("Constraint pool",
6431 sizeof (struct constraint), 30);
6432 variable_info_pool = create_alloc_pool ("Variable info pool",
6433 sizeof (struct variable_info), 30);
6434 constraints = VEC_alloc (constraint_t, heap, 8);
6435 varmap = VEC_alloc (varinfo_t, heap, 8);
6436 vi_for_tree = pointer_map_create ();
6437 call_stmt_vars = pointer_map_create ();
6439 memset (&stats, 0, sizeof (stats));
6440 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6441 shared_bitmap_eq, free);
6444 gcc_obstack_init (&fake_var_decl_obstack);
6447 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6448 predecessor edges. */
6451 remove_preds_and_fake_succs (constraint_graph_t graph)
6455 /* Clear the implicit ref and address nodes from the successor
6457 for (i = 0; i < FIRST_REF_NODE; i++)
6459 if (graph->succs[i])
6460 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6461 FIRST_REF_NODE * 2);
6464 /* Free the successor list for the non-ref nodes. */
6465 for (i = FIRST_REF_NODE; i < graph->size; i++)
6467 if (graph->succs[i])
6468 BITMAP_FREE (graph->succs[i]);
6471 /* Now reallocate the size of the successor list as, and blow away
6472 the predecessor bitmaps. */
6473 graph->size = VEC_length (varinfo_t, varmap);
6474 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6476 free (graph->implicit_preds);
6477 graph->implicit_preds = NULL;
6478 free (graph->preds);
6479 graph->preds = NULL;
6480 bitmap_obstack_release (&predbitmap_obstack);
6483 /* Solve the constraint set. */
6486 solve_constraints (void)
6488 struct scc_info *si;
6492 "\nCollapsing static cycles and doing variable "
6495 init_graph (VEC_length (varinfo_t, varmap) * 2);
6498 fprintf (dump_file, "Building predecessor graph\n");
6499 build_pred_graph ();
6502 fprintf (dump_file, "Detecting pointer and location "
6504 si = perform_var_substitution (graph);
6507 fprintf (dump_file, "Rewriting constraints and unifying "
6509 rewrite_constraints (graph, si);
6511 build_succ_graph ();
6513 free_var_substitution_info (si);
6515 /* Attach complex constraints to graph nodes. */
6516 move_complex_constraints (graph);
6519 fprintf (dump_file, "Uniting pointer but not location equivalent "
6521 unite_pointer_equivalences (graph);
6524 fprintf (dump_file, "Finding indirect cycles\n");
6525 find_indirect_cycles (graph);
6527 /* Implicit nodes and predecessors are no longer necessary at this
6529 remove_preds_and_fake_succs (graph);
6531 if (dump_file && (dump_flags & TDF_GRAPH))
6533 fprintf (dump_file, "\n\n// The constraint graph before solve-graph "
6534 "in dot format:\n");
6535 dump_constraint_graph (dump_file);
6536 fprintf (dump_file, "\n\n");
6540 fprintf (dump_file, "Solving graph\n");
6542 solve_graph (graph);
6544 if (dump_file && (dump_flags & TDF_GRAPH))
6546 fprintf (dump_file, "\n\n// The constraint graph after solve-graph "
6547 "in dot format:\n");
6548 dump_constraint_graph (dump_file);
6549 fprintf (dump_file, "\n\n");
6553 dump_sa_points_to_info (dump_file);
6556 /* Create points-to sets for the current function. See the comments
6557 at the start of the file for an algorithmic overview. */
6560 compute_points_to_sets (void)
6566 timevar_push (TV_TREE_PTA);
6570 intra_create_variable_infos ();
6572 /* Now walk all statements and build the constraint set. */
6575 gimple_stmt_iterator gsi;
6577 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6579 gimple phi = gsi_stmt (gsi);
6581 if (is_gimple_reg (gimple_phi_result (phi)))
6582 find_func_aliases (phi);
6585 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6587 gimple stmt = gsi_stmt (gsi);
6589 find_func_aliases (stmt);
6595 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6596 dump_constraints (dump_file, 0);
6599 /* From the constraints compute the points-to sets. */
6600 solve_constraints ();
6602 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6603 find_what_var_points_to (get_varinfo (escaped_id),
6604 &cfun->gimple_df->escaped);
6606 /* Make sure the ESCAPED solution (which is used as placeholder in
6607 other solutions) does not reference itself. This simplifies
6608 points-to solution queries. */
6609 cfun->gimple_df->escaped.escaped = 0;
6611 /* Mark escaped HEAP variables as global. */
6612 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6614 && !vi->is_global_var)
6615 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6616 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6618 /* Compute the points-to sets for pointer SSA_NAMEs. */
6619 for (i = 0; i < num_ssa_names; ++i)
6621 tree ptr = ssa_name (i);
6623 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6624 find_what_p_points_to (ptr);
6627 /* Compute the call-used/clobbered sets. */
6630 gimple_stmt_iterator gsi;
6632 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6634 gimple stmt = gsi_stmt (gsi);
6635 struct pt_solution *pt;
6636 if (!is_gimple_call (stmt))
6639 pt = gimple_call_use_set (stmt);
6640 if (gimple_call_flags (stmt) & ECF_CONST)
6641 memset (pt, 0, sizeof (struct pt_solution));
6642 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6644 find_what_var_points_to (vi, pt);
6645 /* Escaped (and thus nonlocal) variables are always
6646 implicitly used by calls. */
6647 /* ??? ESCAPED can be empty even though NONLOCAL
6654 /* If there is nothing special about this call then
6655 we have made everything that is used also escape. */
6656 *pt = cfun->gimple_df->escaped;
6660 pt = gimple_call_clobber_set (stmt);
6661 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6662 memset (pt, 0, sizeof (struct pt_solution));
6663 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6665 find_what_var_points_to (vi, pt);
6666 /* Escaped (and thus nonlocal) variables are always
6667 implicitly clobbered by calls. */
6668 /* ??? ESCAPED can be empty even though NONLOCAL
6675 /* If there is nothing special about this call then
6676 we have made everything that is used also escape. */
6677 *pt = cfun->gimple_df->escaped;
6683 timevar_pop (TV_TREE_PTA);
6687 /* Delete created points-to sets. */
6690 delete_points_to_sets (void)
6694 htab_delete (shared_bitmap_table);
6695 if (dump_file && (dump_flags & TDF_STATS))
6696 fprintf (dump_file, "Points to sets created:%d\n",
6697 stats.points_to_sets_created);
6699 pointer_map_destroy (vi_for_tree);
6700 pointer_map_destroy (call_stmt_vars);
6701 bitmap_obstack_release (&pta_obstack);
6702 VEC_free (constraint_t, heap, constraints);
6704 for (i = 0; i < graph->size; i++)
6705 VEC_free (constraint_t, heap, graph->complex[i]);
6706 free (graph->complex);
6709 free (graph->succs);
6711 free (graph->pe_rep);
6712 free (graph->indirect_cycles);
6715 VEC_free (varinfo_t, heap, varmap);
6716 free_alloc_pool (variable_info_pool);
6717 free_alloc_pool (constraint_pool);
6719 obstack_free (&fake_var_decl_obstack, NULL);
6723 /* Compute points-to information for every SSA_NAME pointer in the
6724 current function and compute the transitive closure of escaped
6725 variables to re-initialize the call-clobber states of local variables. */
6728 compute_may_aliases (void)
6730 if (cfun->gimple_df->ipa_pta)
6734 fprintf (dump_file, "\nNot re-computing points-to information "
6735 "because IPA points-to information is available.\n\n");
6737 /* But still dump what we have remaining it. */
6738 dump_alias_info (dump_file);
6740 if (dump_flags & TDF_DETAILS)
6741 dump_referenced_vars (dump_file);
6747 /* For each pointer P_i, determine the sets of variables that P_i may
6748 point-to. Compute the reachability set of escaped and call-used
6750 compute_points_to_sets ();
6752 /* Debugging dumps. */
6755 dump_alias_info (dump_file);
6757 if (dump_flags & TDF_DETAILS)
6758 dump_referenced_vars (dump_file);
6761 /* Deallocate memory used by aliasing data structures and the internal
6762 points-to solution. */
6763 delete_points_to_sets ();
6765 gcc_assert (!need_ssa_update_p (cfun));
6771 gate_tree_pta (void)
6773 return flag_tree_pta;
6776 /* A dummy pass to cause points-to information to be computed via
6777 TODO_rebuild_alias. */
6779 struct gimple_opt_pass pass_build_alias =
6784 gate_tree_pta, /* gate */
6788 0, /* static_pass_number */
6789 TV_NONE, /* tv_id */
6790 PROP_cfg | PROP_ssa, /* properties_required */
6791 0, /* properties_provided */
6792 0, /* properties_destroyed */
6793 0, /* todo_flags_start */
6794 TODO_rebuild_alias /* todo_flags_finish */
6798 /* A dummy pass to cause points-to information to be computed via
6799 TODO_rebuild_alias. */
6801 struct gimple_opt_pass pass_build_ealias =
6805 "ealias", /* name */
6806 gate_tree_pta, /* gate */
6810 0, /* static_pass_number */
6811 TV_NONE, /* tv_id */
6812 PROP_cfg | PROP_ssa, /* properties_required */
6813 0, /* properties_provided */
6814 0, /* properties_destroyed */
6815 0, /* todo_flags_start */
6816 TODO_rebuild_alias /* todo_flags_finish */
6821 /* Return true if we should execute IPA PTA. */
6827 /* Don't bother doing anything if the program has errors. */
6831 /* IPA PTA solutions for ESCAPED. */
6832 struct pt_solution ipa_escaped_pt
6833 = { true, false, false, false, false, false, NULL };
6835 /* Associate node with varinfo DATA. Worker for
6836 cgraph_for_node_and_aliases. */
6838 associate_varinfo_to_alias (struct cgraph_node *node, void *data)
6840 if (node->alias || node->thunk.thunk_p)
6841 insert_vi_for_tree (node->decl, (varinfo_t)data);
6845 /* Execute the driver for IPA PTA. */
6847 ipa_pta_execute (void)
6849 struct cgraph_node *node;
6850 struct varpool_node *var;
6857 if (dump_file && (dump_flags & TDF_DETAILS))
6859 dump_cgraph (dump_file);
6860 fprintf (dump_file, "\n");
6863 /* Build the constraints. */
6864 for (node = cgraph_nodes; node; node = node->next)
6867 /* Nodes without a body are not interesting. Especially do not
6868 visit clones at this point for now - we get duplicate decls
6869 there for inline clones at least. */
6870 if (!cgraph_function_with_gimple_body_p (node))
6873 gcc_assert (!node->clone_of);
6875 vi = create_function_info_for (node->decl,
6876 alias_get_name (node->decl));
6877 cgraph_for_node_and_aliases (node, associate_varinfo_to_alias, vi, true);
6880 /* Create constraints for global variables and their initializers. */
6881 for (var = varpool_nodes; var; var = var->next)
6886 get_vi_for_tree (var->decl);
6892 "Generating constraints for global initializers\n\n");
6893 dump_constraints (dump_file, 0);
6894 fprintf (dump_file, "\n");
6896 from = VEC_length (constraint_t, constraints);
6898 for (node = cgraph_nodes; node; node = node->next)
6900 struct function *func;
6904 /* Nodes without a body are not interesting. */
6905 if (!cgraph_function_with_gimple_body_p (node))
6911 "Generating constraints for %s", cgraph_node_name (node));
6912 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6913 fprintf (dump_file, " (%s)",
6914 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6915 fprintf (dump_file, "\n");
6918 func = DECL_STRUCT_FUNCTION (node->decl);
6919 old_func_decl = current_function_decl;
6921 current_function_decl = node->decl;
6923 /* For externally visible or attribute used annotated functions use
6924 local constraints for their arguments.
6925 For local functions we see all callers and thus do not need initial
6926 constraints for parameters. */
6927 if (node->reachable_from_other_partition
6928 || node->local.externally_visible
6931 intra_create_variable_infos ();
6933 /* We also need to make function return values escape. Nothing
6934 escapes by returning from main though. */
6935 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6938 fi = lookup_vi_for_tree (node->decl);
6939 rvi = first_vi_for_offset (fi, fi_result);
6940 if (rvi && rvi->offset == fi_result)
6942 struct constraint_expr includes;
6943 struct constraint_expr var;
6944 includes.var = escaped_id;
6945 includes.offset = 0;
6946 includes.type = SCALAR;
6950 process_constraint (new_constraint (includes, var));
6955 /* Build constriants for the function body. */
6956 FOR_EACH_BB_FN (bb, func)
6958 gimple_stmt_iterator gsi;
6960 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6963 gimple phi = gsi_stmt (gsi);
6965 if (is_gimple_reg (gimple_phi_result (phi)))
6966 find_func_aliases (phi);
6969 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6971 gimple stmt = gsi_stmt (gsi);
6973 find_func_aliases (stmt);
6974 find_func_clobbers (stmt);
6978 current_function_decl = old_func_decl;
6983 fprintf (dump_file, "\n");
6984 dump_constraints (dump_file, from);
6985 fprintf (dump_file, "\n");
6987 from = VEC_length (constraint_t, constraints);
6990 /* From the constraints compute the points-to sets. */
6991 solve_constraints ();
6993 /* Compute the global points-to sets for ESCAPED.
6994 ??? Note that the computed escape set is not correct
6995 for the whole unit as we fail to consider graph edges to
6996 externally visible functions. */
6997 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6999 /* Make sure the ESCAPED solution (which is used as placeholder in
7000 other solutions) does not reference itself. This simplifies
7001 points-to solution queries. */
7002 ipa_escaped_pt.ipa_escaped = 0;
7004 /* Assign the points-to sets to the SSA names in the unit. */
7005 for (node = cgraph_nodes; node; node = node->next)
7008 struct function *fn;
7012 struct pt_solution uses, clobbers;
7013 struct cgraph_edge *e;
7015 /* Nodes without a body are not interesting. */
7016 if (!cgraph_function_with_gimple_body_p (node))
7019 fn = DECL_STRUCT_FUNCTION (node->decl);
7021 /* Compute the points-to sets for pointer SSA_NAMEs. */
7022 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
7025 && POINTER_TYPE_P (TREE_TYPE (ptr)))
7026 find_what_p_points_to (ptr);
7029 /* Compute the call-use and call-clobber sets for all direct calls. */
7030 fi = lookup_vi_for_tree (node->decl);
7031 gcc_assert (fi->is_fn_info);
7032 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
7034 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
7035 for (e = node->callers; e; e = e->next_caller)
7040 *gimple_call_clobber_set (e->call_stmt) = clobbers;
7041 *gimple_call_use_set (e->call_stmt) = uses;
7044 /* Compute the call-use and call-clobber sets for indirect calls
7045 and calls to external functions. */
7046 FOR_EACH_BB_FN (bb, fn)
7048 gimple_stmt_iterator gsi;
7050 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
7052 gimple stmt = gsi_stmt (gsi);
7053 struct pt_solution *pt;
7057 if (!is_gimple_call (stmt))
7060 /* Handle direct calls to external functions. */
7061 decl = gimple_call_fndecl (stmt);
7063 && (!(fi = lookup_vi_for_tree (decl))
7064 || !fi->is_fn_info))
7066 pt = gimple_call_use_set (stmt);
7067 if (gimple_call_flags (stmt) & ECF_CONST)
7068 memset (pt, 0, sizeof (struct pt_solution));
7069 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
7071 find_what_var_points_to (vi, pt);
7072 /* Escaped (and thus nonlocal) variables are always
7073 implicitly used by calls. */
7074 /* ??? ESCAPED can be empty even though NONLOCAL
7077 pt->ipa_escaped = 1;
7081 /* If there is nothing special about this call then
7082 we have made everything that is used also escape. */
7083 *pt = ipa_escaped_pt;
7087 pt = gimple_call_clobber_set (stmt);
7088 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
7089 memset (pt, 0, sizeof (struct pt_solution));
7090 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
7092 find_what_var_points_to (vi, pt);
7093 /* Escaped (and thus nonlocal) variables are always
7094 implicitly clobbered by calls. */
7095 /* ??? ESCAPED can be empty even though NONLOCAL
7098 pt->ipa_escaped = 1;
7102 /* If there is nothing special about this call then
7103 we have made everything that is used also escape. */
7104 *pt = ipa_escaped_pt;
7109 /* Handle indirect calls. */
7111 && (fi = get_fi_for_callee (stmt)))
7113 /* We need to accumulate all clobbers/uses of all possible
7115 fi = get_varinfo (find (fi->id));
7116 /* If we cannot constrain the set of functions we'll end up
7117 calling we end up using/clobbering everything. */
7118 if (bitmap_bit_p (fi->solution, anything_id)
7119 || bitmap_bit_p (fi->solution, nonlocal_id)
7120 || bitmap_bit_p (fi->solution, escaped_id))
7122 pt_solution_reset (gimple_call_clobber_set (stmt));
7123 pt_solution_reset (gimple_call_use_set (stmt));
7129 struct pt_solution *uses, *clobbers;
7131 uses = gimple_call_use_set (stmt);
7132 clobbers = gimple_call_clobber_set (stmt);
7133 memset (uses, 0, sizeof (struct pt_solution));
7134 memset (clobbers, 0, sizeof (struct pt_solution));
7135 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7137 struct pt_solution sol;
7139 vi = get_varinfo (i);
7140 if (!vi->is_fn_info)
7142 /* ??? We could be more precise here? */
7144 uses->ipa_escaped = 1;
7145 clobbers->nonlocal = 1;
7146 clobbers->ipa_escaped = 1;
7150 if (!uses->anything)
7152 find_what_var_points_to
7153 (first_vi_for_offset (vi, fi_uses), &sol);
7154 pt_solution_ior_into (uses, &sol);
7156 if (!clobbers->anything)
7158 find_what_var_points_to
7159 (first_vi_for_offset (vi, fi_clobbers), &sol);
7160 pt_solution_ior_into (clobbers, &sol);
7168 fn->gimple_df->ipa_pta = true;
7171 delete_points_to_sets ();
7178 struct simple_ipa_opt_pass pass_ipa_pta =
7183 gate_ipa_pta, /* gate */
7184 ipa_pta_execute, /* execute */
7187 0, /* static_pass_number */
7188 TV_IPA_PTA, /* tv_id */
7189 0, /* properties_required */
7190 0, /* properties_provided */
7191 0, /* properties_destroyed */
7192 0, /* todo_flags_start */
7193 TODO_update_ssa /* todo_flags_finish */