1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dberlin@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "basic-block.h"
33 #include "tree-flow.h"
34 #include "tree-inline.h"
35 #include "diagnostic-core.h"
41 #include "tree-pass.h"
43 #include "alloc-pool.h"
44 #include "splay-tree.h"
48 #include "pointer-set.h"
50 /* The idea behind this analyzer is to generate set constraints from the
51 program, then solve the resulting constraints in order to generate the
54 Set constraints are a way of modeling program analysis problems that
55 involve sets. They consist of an inclusion constraint language,
56 describing the variables (each variable is a set) and operations that
57 are involved on the variables, and a set of rules that derive facts
58 from these operations. To solve a system of set constraints, you derive
59 all possible facts under the rules, which gives you the correct sets
62 See "Efficient Field-sensitive pointer analysis for C" by "David
63 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
64 http://citeseer.ist.psu.edu/pearce04efficient.html
66 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
67 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
68 http://citeseer.ist.psu.edu/heintze01ultrafast.html
70 There are three types of real constraint expressions, DEREF,
71 ADDRESSOF, and SCALAR. Each constraint expression consists
72 of a constraint type, a variable, and an offset.
74 SCALAR is a constraint expression type used to represent x, whether
75 it appears on the LHS or the RHS of a statement.
76 DEREF is a constraint expression type used to represent *x, whether
77 it appears on the LHS or the RHS of a statement.
78 ADDRESSOF is a constraint expression used to represent &x, whether
79 it appears on the LHS or the RHS of a statement.
81 Each pointer variable in the program is assigned an integer id, and
82 each field of a structure variable is assigned an integer id as well.
84 Structure variables are linked to their list of fields through a "next
85 field" in each variable that points to the next field in offset
87 Each variable for a structure field has
89 1. "size", that tells the size in bits of that field.
90 2. "fullsize, that tells the size in bits of the entire structure.
91 3. "offset", that tells the offset in bits from the beginning of the
92 structure to this field.
104 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
105 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
106 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
109 In order to solve the system of set constraints, the following is
112 1. Each constraint variable x has a solution set associated with it,
115 2. Constraints are separated into direct, copy, and complex.
116 Direct constraints are ADDRESSOF constraints that require no extra
117 processing, such as P = &Q
118 Copy constraints are those of the form P = Q.
119 Complex constraints are all the constraints involving dereferences
120 and offsets (including offsetted copies).
122 3. All direct constraints of the form P = &Q are processed, such
123 that Q is added to Sol(P)
125 4. All complex constraints for a given constraint variable are stored in a
126 linked list attached to that variable's node.
128 5. A directed graph is built out of the copy constraints. Each
129 constraint variable is a node in the graph, and an edge from
130 Q to P is added for each copy constraint of the form P = Q
132 6. The graph is then walked, and solution sets are
133 propagated along the copy edges, such that an edge from Q to P
134 causes Sol(P) <- Sol(P) union Sol(Q).
136 7. As we visit each node, all complex constraints associated with
137 that node are processed by adding appropriate copy edges to the graph, or the
138 appropriate variables to the solution set.
140 8. The process of walking the graph is iterated until no solution
143 Prior to walking the graph in steps 6 and 7, We perform static
144 cycle elimination on the constraint graph, as well
145 as off-line variable substitution.
147 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
148 on and turned into anything), but isn't. You can just see what offset
149 inside the pointed-to struct it's going to access.
151 TODO: Constant bounded arrays can be handled as if they were structs of the
152 same number of elements.
154 TODO: Modeling heap and incoming pointers becomes much better if we
155 add fields to them as we discover them, which we could do.
157 TODO: We could handle unions, but to be honest, it's probably not
158 worth the pain or slowdown. */
160 /* IPA-PTA optimizations possible.
162 When the indirect function called is ANYTHING we can add disambiguation
163 based on the function signatures (or simply the parameter count which
164 is the varinfo size). We also do not need to consider functions that
165 do not have their address taken.
167 The is_global_var bit which marks escape points is overly conservative
168 in IPA mode. Split it to is_escape_point and is_global_var - only
169 externally visible globals are escape points in IPA mode. This is
170 also needed to fix the pt_solution_includes_global predicate
171 (and thus ptr_deref_may_alias_global_p).
173 The way we introduce DECL_PT_UID to avoid fixing up all points-to
174 sets in the translation unit when we copy a DECL during inlining
175 pessimizes precision. The advantage is that the DECL_PT_UID keeps
176 compile-time and memory usage overhead low - the points-to sets
177 do not grow or get unshared as they would during a fixup phase.
178 An alternative solution is to delay IPA PTA until after all
179 inlining transformations have been applied.
181 The way we propagate clobber/use information isn't optimized.
182 It should use a new complex constraint that properly filters
183 out local variables of the callee (though that would make
184 the sets invalid after inlining). OTOH we might as well
185 admit defeat to WHOPR and simply do all the clobber/use analysis
186 and propagation after PTA finished but before we threw away
187 points-to information for memory variables. WHOPR and PTA
188 do not play along well anyway - the whole constraint solving
189 would need to be done in WPA phase and it will be very interesting
190 to apply the results to local SSA names during LTRANS phase.
192 We probably should compute a per-function unit-ESCAPE solution
193 propagating it simply like the clobber / uses solutions. The
194 solution can go alongside the non-IPA espaced solution and be
195 used to query which vars escape the unit through a function.
197 We never put function decls in points-to sets so we do not
198 keep the set of called functions for indirect calls.
200 And probably more. */
201 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct heapvar_map)))
202 htab_t heapvar_for_stmt;
204 static bool use_field_sensitive = true;
205 static int in_ipa_mode = 0;
207 /* Used for predecessor bitmaps. */
208 static bitmap_obstack predbitmap_obstack;
210 /* Used for points-to sets. */
211 static bitmap_obstack pta_obstack;
213 /* Used for oldsolution members of variables. */
214 static bitmap_obstack oldpta_obstack;
216 /* Used for per-solver-iteration bitmaps. */
217 static bitmap_obstack iteration_obstack;
219 static unsigned int create_variable_info_for (tree, const char *);
220 typedef struct constraint_graph *constraint_graph_t;
221 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
224 typedef struct constraint *constraint_t;
226 DEF_VEC_P(constraint_t);
227 DEF_VEC_ALLOC_P(constraint_t,heap);
229 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
231 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
233 static struct constraint_stats
235 unsigned int total_vars;
236 unsigned int nonpointer_vars;
237 unsigned int unified_vars_static;
238 unsigned int unified_vars_dynamic;
239 unsigned int iterations;
240 unsigned int num_edges;
241 unsigned int num_implicit_edges;
242 unsigned int points_to_sets_created;
247 /* ID of this variable */
250 /* True if this is a variable created by the constraint analysis, such as
251 heap variables and constraints we had to break up. */
252 unsigned int is_artificial_var : 1;
254 /* True if this is a special variable whose solution set should not be
256 unsigned int is_special_var : 1;
258 /* True for variables whose size is not known or variable. */
259 unsigned int is_unknown_size_var : 1;
261 /* True for (sub-)fields that represent a whole variable. */
262 unsigned int is_full_var : 1;
264 /* True if this is a heap variable. */
265 unsigned int is_heap_var : 1;
267 /* True if this is a variable tracking a restrict pointer source. */
268 unsigned int is_restrict_var : 1;
270 /* True if this field may contain pointers. */
271 unsigned int may_have_pointers : 1;
273 /* True if this field has only restrict qualified pointers. */
274 unsigned int only_restrict_pointers : 1;
276 /* True if this represents a global variable. */
277 unsigned int is_global_var : 1;
279 /* True if this represents a IPA function info. */
280 unsigned int is_fn_info : 1;
282 /* A link to the variable for the next field in this structure. */
283 struct variable_info *next;
285 /* Offset of this variable, in bits, from the base variable */
286 unsigned HOST_WIDE_INT offset;
288 /* Size of the variable, in bits. */
289 unsigned HOST_WIDE_INT size;
291 /* Full size of the base variable, in bits. */
292 unsigned HOST_WIDE_INT fullsize;
294 /* Name of this variable */
297 /* Tree that this variable is associated with. */
300 /* Points-to set for this variable. */
303 /* Old points-to set for this variable. */
306 typedef struct variable_info *varinfo_t;
308 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
309 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
310 unsigned HOST_WIDE_INT);
311 static varinfo_t lookup_vi_for_tree (tree);
313 /* Pool of variable info structures. */
314 static alloc_pool variable_info_pool;
316 DEF_VEC_P(varinfo_t);
318 DEF_VEC_ALLOC_P(varinfo_t, heap);
320 /* Table of variable info structures for constraint variables.
321 Indexed directly by variable info id. */
322 static VEC(varinfo_t,heap) *varmap;
324 /* Return the varmap element N */
326 static inline varinfo_t
327 get_varinfo (unsigned int n)
329 return VEC_index (varinfo_t, varmap, n);
332 /* Static IDs for the special variables. */
333 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
334 escaped_id = 3, nonlocal_id = 4,
335 storedanything_id = 5, integer_id = 6 };
337 struct GTY(()) heapvar_map {
339 unsigned HOST_WIDE_INT offset;
343 heapvar_map_eq (const void *p1, const void *p2)
345 const struct heapvar_map *h1 = (const struct heapvar_map *)p1;
346 const struct heapvar_map *h2 = (const struct heapvar_map *)p2;
347 return (h1->map.base.from == h2->map.base.from
348 && h1->offset == h2->offset);
352 heapvar_map_hash (struct heapvar_map *h)
354 return iterative_hash_host_wide_int (h->offset,
355 htab_hash_pointer (h->map.base.from));
358 /* Lookup a heap var for FROM, and return it if we find one. */
361 heapvar_lookup (tree from, unsigned HOST_WIDE_INT offset)
363 struct heapvar_map *h, in;
364 in.map.base.from = from;
366 h = (struct heapvar_map *) htab_find_with_hash (heapvar_for_stmt, &in,
367 heapvar_map_hash (&in));
373 /* Insert a mapping FROM->TO in the heap var for statement
377 heapvar_insert (tree from, unsigned HOST_WIDE_INT offset, tree to)
379 struct heapvar_map *h;
382 h = ggc_alloc_heapvar_map ();
383 h->map.base.from = from;
385 h->map.hash = heapvar_map_hash (h);
387 loc = htab_find_slot_with_hash (heapvar_for_stmt, h, h->map.hash, INSERT);
388 gcc_assert (*loc == NULL);
389 *(struct heapvar_map **) loc = h;
392 /* Return a new variable info structure consisting for a variable
393 named NAME, and using constraint graph node NODE. Append it
394 to the vector of variable info structures. */
397 new_var_info (tree t, const char *name)
399 unsigned index = VEC_length (varinfo_t, varmap);
400 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
405 /* Vars without decl are artificial and do not have sub-variables. */
406 ret->is_artificial_var = (t == NULL_TREE);
407 ret->is_special_var = false;
408 ret->is_unknown_size_var = false;
409 ret->is_full_var = (t == NULL_TREE);
410 ret->is_heap_var = false;
411 ret->is_restrict_var = false;
412 ret->may_have_pointers = true;
413 ret->only_restrict_pointers = false;
414 ret->is_global_var = (t == NULL_TREE);
415 ret->is_fn_info = false;
417 ret->is_global_var = is_global_var (t);
418 ret->solution = BITMAP_ALLOC (&pta_obstack);
419 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
424 VEC_safe_push (varinfo_t, heap, varmap, ret);
430 /* A map mapping call statements to per-stmt variables for uses
431 and clobbers specific to the call. */
432 struct pointer_map_t *call_stmt_vars;
434 /* Lookup or create the variable for the call statement CALL. */
437 get_call_vi (gimple call)
442 slot_p = pointer_map_insert (call_stmt_vars, call);
444 return (varinfo_t) *slot_p;
446 vi = new_var_info (NULL_TREE, "CALLUSED");
450 vi->is_full_var = true;
452 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
456 vi2->is_full_var = true;
458 *slot_p = (void *) vi;
462 /* Lookup the variable for the call statement CALL representing
463 the uses. Returns NULL if there is nothing special about this call. */
466 lookup_call_use_vi (gimple call)
470 slot_p = pointer_map_contains (call_stmt_vars, call);
472 return (varinfo_t) *slot_p;
477 /* Lookup the variable for the call statement CALL representing
478 the clobbers. Returns NULL if there is nothing special about this call. */
481 lookup_call_clobber_vi (gimple call)
483 varinfo_t uses = lookup_call_use_vi (call);
490 /* Lookup or create the variable for the call statement CALL representing
494 get_call_use_vi (gimple call)
496 return get_call_vi (call);
499 /* Lookup or create the variable for the call statement CALL representing
502 static varinfo_t ATTRIBUTE_UNUSED
503 get_call_clobber_vi (gimple call)
505 return get_call_vi (call)->next;
509 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
511 /* An expression that appears in a constraint. */
513 struct constraint_expr
515 /* Constraint type. */
516 constraint_expr_type type;
518 /* Variable we are referring to in the constraint. */
521 /* Offset, in bits, of this constraint from the beginning of
522 variables it ends up referring to.
524 IOW, in a deref constraint, we would deref, get the result set,
525 then add OFFSET to each member. */
526 HOST_WIDE_INT offset;
529 /* Use 0x8000... as special unknown offset. */
530 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
532 typedef struct constraint_expr ce_s;
534 DEF_VEC_ALLOC_O(ce_s, heap);
535 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
536 static void get_constraint_for (tree, VEC(ce_s, heap) **);
537 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
538 static void do_deref (VEC (ce_s, heap) **);
540 /* Our set constraints are made up of two constraint expressions, one
543 As described in the introduction, our set constraints each represent an
544 operation between set valued variables.
548 struct constraint_expr lhs;
549 struct constraint_expr rhs;
552 /* List of constraints that we use to build the constraint graph from. */
554 static VEC(constraint_t,heap) *constraints;
555 static alloc_pool constraint_pool;
557 /* The constraint graph is represented as an array of bitmaps
558 containing successor nodes. */
560 struct constraint_graph
562 /* Size of this graph, which may be different than the number of
563 nodes in the variable map. */
566 /* Explicit successors of each node. */
569 /* Implicit predecessors of each node (Used for variable
571 bitmap *implicit_preds;
573 /* Explicit predecessors of each node (Used for variable substitution). */
576 /* Indirect cycle representatives, or -1 if the node has no indirect
578 int *indirect_cycles;
580 /* Representative node for a node. rep[a] == a unless the node has
584 /* Equivalence class representative for a label. This is used for
585 variable substitution. */
588 /* Pointer equivalence label for a node. All nodes with the same
589 pointer equivalence label can be unified together at some point
590 (either during constraint optimization or after the constraint
594 /* Pointer equivalence representative for a label. This is used to
595 handle nodes that are pointer equivalent but not location
596 equivalent. We can unite these once the addressof constraints
597 are transformed into initial points-to sets. */
600 /* Pointer equivalence label for each node, used during variable
602 unsigned int *pointer_label;
604 /* Location equivalence label for each node, used during location
605 equivalence finding. */
606 unsigned int *loc_label;
608 /* Pointed-by set for each node, used during location equivalence
609 finding. This is pointed-by rather than pointed-to, because it
610 is constructed using the predecessor graph. */
613 /* Points to sets for pointer equivalence. This is *not* the actual
614 points-to sets for nodes. */
617 /* Bitmap of nodes where the bit is set if the node is a direct
618 node. Used for variable substitution. */
619 sbitmap direct_nodes;
621 /* Bitmap of nodes where the bit is set if the node is address
622 taken. Used for variable substitution. */
623 bitmap address_taken;
625 /* Vector of complex constraints for each graph node. Complex
626 constraints are those involving dereferences or offsets that are
628 VEC(constraint_t,heap) **complex;
631 static constraint_graph_t graph;
633 /* During variable substitution and the offline version of indirect
634 cycle finding, we create nodes to represent dereferences and
635 address taken constraints. These represent where these start and
637 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
638 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
640 /* Return the representative node for NODE, if NODE has been unioned
642 This function performs path compression along the way to finding
643 the representative. */
646 find (unsigned int node)
648 gcc_assert (node < graph->size);
649 if (graph->rep[node] != node)
650 return graph->rep[node] = find (graph->rep[node]);
654 /* Union the TO and FROM nodes to the TO nodes.
655 Note that at some point in the future, we may want to do
656 union-by-rank, in which case we are going to have to return the
657 node we unified to. */
660 unite (unsigned int to, unsigned int from)
662 gcc_assert (to < graph->size && from < graph->size);
663 if (to != from && graph->rep[from] != to)
665 graph->rep[from] = to;
671 /* Create a new constraint consisting of LHS and RHS expressions. */
674 new_constraint (const struct constraint_expr lhs,
675 const struct constraint_expr rhs)
677 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
683 /* Print out constraint C to FILE. */
686 dump_constraint (FILE *file, constraint_t c)
688 if (c->lhs.type == ADDRESSOF)
690 else if (c->lhs.type == DEREF)
692 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
693 if (c->lhs.offset == UNKNOWN_OFFSET)
694 fprintf (file, " + UNKNOWN");
695 else if (c->lhs.offset != 0)
696 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
697 fprintf (file, " = ");
698 if (c->rhs.type == ADDRESSOF)
700 else if (c->rhs.type == DEREF)
702 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
703 if (c->rhs.offset == UNKNOWN_OFFSET)
704 fprintf (file, " + UNKNOWN");
705 else if (c->rhs.offset != 0)
706 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
707 fprintf (file, "\n");
711 void debug_constraint (constraint_t);
712 void debug_constraints (void);
713 void debug_constraint_graph (void);
714 void debug_solution_for_var (unsigned int);
715 void debug_sa_points_to_info (void);
717 /* Print out constraint C to stderr. */
720 debug_constraint (constraint_t c)
722 dump_constraint (stderr, c);
725 /* Print out all constraints to FILE */
728 dump_constraints (FILE *file, int from)
732 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
733 dump_constraint (file, c);
736 /* Print out all constraints to stderr. */
739 debug_constraints (void)
741 dump_constraints (stderr, 0);
744 /* Print out to FILE the edge in the constraint graph that is created by
745 constraint c. The edge may have a label, depending on the type of
746 constraint that it represents. If complex1, e.g: a = *b, then the label
747 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
748 complex with an offset, e.g: a = b + 8, then the label is "+".
749 Otherwise the edge has no label. */
752 dump_constraint_edge (FILE *file, constraint_t c)
754 if (c->rhs.type != ADDRESSOF)
756 const char *src = get_varinfo (c->rhs.var)->name;
757 const char *dst = get_varinfo (c->lhs.var)->name;
758 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
759 /* Due to preprocessing of constraints, instructions like *a = *b are
760 illegal; thus, we do not have to handle such cases. */
761 if (c->lhs.type == DEREF)
762 fprintf (file, " [ label=\"*=\" ] ;\n");
763 else if (c->rhs.type == DEREF)
764 fprintf (file, " [ label=\"=*\" ] ;\n");
767 /* We must check the case where the constraint is an offset.
768 In this case, it is treated as a complex constraint. */
769 if (c->rhs.offset != c->lhs.offset)
770 fprintf (file, " [ label=\"+\" ] ;\n");
772 fprintf (file, " ;\n");
777 /* Print the constraint graph in dot format. */
780 dump_constraint_graph (FILE *file)
782 unsigned int i=0, size;
785 /* Only print the graph if it has already been initialized: */
789 /* Print the constraints used to produce the constraint graph. The
790 constraints will be printed as comments in the dot file: */
791 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
792 dump_constraints (file, 0);
793 fprintf (file, "*/\n");
795 /* Prints the header of the dot file: */
796 fprintf (file, "\n\n// The constraint graph in dot format:\n");
797 fprintf (file, "strict digraph {\n");
798 fprintf (file, " node [\n shape = box\n ]\n");
799 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
800 fprintf (file, "\n // List of nodes in the constraint graph:\n");
802 /* The next lines print the nodes in the graph. In order to get the
803 number of nodes in the graph, we must choose the minimum between the
804 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
805 yet been initialized, then graph->size == 0, otherwise we must only
806 read nodes that have an entry in VEC (varinfo_t, varmap). */
807 size = VEC_length (varinfo_t, varmap);
808 size = size < graph->size ? size : graph->size;
809 for (i = 0; i < size; i++)
811 const char *name = get_varinfo (graph->rep[i])->name;
812 fprintf (file, " \"%s\" ;\n", name);
815 /* Go over the list of constraints printing the edges in the constraint
817 fprintf (file, "\n // The constraint edges:\n");
818 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
820 dump_constraint_edge (file, c);
822 /* Prints the tail of the dot file. By now, only the closing bracket. */
823 fprintf (file, "}\n\n\n");
826 /* Print out the constraint graph to stderr. */
829 debug_constraint_graph (void)
831 dump_constraint_graph (stderr);
836 The solver is a simple worklist solver, that works on the following
839 sbitmap changed_nodes = all zeroes;
841 For each node that is not already collapsed:
843 set bit in changed nodes
845 while (changed_count > 0)
847 compute topological ordering for constraint graph
849 find and collapse cycles in the constraint graph (updating
850 changed if necessary)
852 for each node (n) in the graph in topological order:
855 Process each complex constraint associated with the node,
856 updating changed if necessary.
858 For each outgoing edge from n, propagate the solution from n to
859 the destination of the edge, updating changed as necessary.
863 /* Return true if two constraint expressions A and B are equal. */
866 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
868 return a.type == b.type && a.var == b.var && a.offset == b.offset;
871 /* Return true if constraint expression A is less than constraint expression
872 B. This is just arbitrary, but consistent, in order to give them an
876 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
878 if (a.type == b.type)
881 return a.offset < b.offset;
883 return a.var < b.var;
886 return a.type < b.type;
889 /* Return true if constraint A is less than constraint B. This is just
890 arbitrary, but consistent, in order to give them an ordering. */
893 constraint_less (const constraint_t a, const constraint_t b)
895 if (constraint_expr_less (a->lhs, b->lhs))
897 else if (constraint_expr_less (b->lhs, a->lhs))
900 return constraint_expr_less (a->rhs, b->rhs);
903 /* Return true if two constraints A and B are equal. */
906 constraint_equal (struct constraint a, struct constraint b)
908 return constraint_expr_equal (a.lhs, b.lhs)
909 && constraint_expr_equal (a.rhs, b.rhs);
913 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
916 constraint_vec_find (VEC(constraint_t,heap) *vec,
917 struct constraint lookfor)
925 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
926 if (place >= VEC_length (constraint_t, vec))
928 found = VEC_index (constraint_t, vec, place);
929 if (!constraint_equal (*found, lookfor))
934 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
937 constraint_set_union (VEC(constraint_t,heap) **to,
938 VEC(constraint_t,heap) **from)
943 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
945 if (constraint_vec_find (*to, *c) == NULL)
947 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
949 VEC_safe_insert (constraint_t, heap, *to, place, c);
954 /* Expands the solution in SET to all sub-fields of variables included.
955 Union the expanded result into RESULT. */
958 solution_set_expand (bitmap result, bitmap set)
964 /* In a first pass record all variables we need to add all
965 sub-fields off. This avoids quadratic behavior. */
966 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
968 varinfo_t v = get_varinfo (j);
969 if (v->is_artificial_var
972 v = lookup_vi_for_tree (v->decl);
974 vars = BITMAP_ALLOC (NULL);
975 bitmap_set_bit (vars, v->id);
978 /* In the second pass now do the addition to the solution and
979 to speed up solving add it to the delta as well. */
982 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
984 varinfo_t v = get_varinfo (j);
985 for (; v != NULL; v = v->next)
986 bitmap_set_bit (result, v->id);
992 /* Take a solution set SET, add OFFSET to each member of the set, and
993 overwrite SET with the result when done. */
996 solution_set_add (bitmap set, HOST_WIDE_INT offset)
998 bitmap result = BITMAP_ALLOC (&iteration_obstack);
1002 /* If the offset is unknown we have to expand the solution to
1004 if (offset == UNKNOWN_OFFSET)
1006 solution_set_expand (set, set);
1010 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
1012 varinfo_t vi = get_varinfo (i);
1014 /* If this is a variable with just one field just set its bit
1016 if (vi->is_artificial_var
1017 || vi->is_unknown_size_var
1019 bitmap_set_bit (result, i);
1022 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
1024 /* If the offset makes the pointer point to before the
1025 variable use offset zero for the field lookup. */
1027 && fieldoffset > vi->offset)
1031 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
1033 bitmap_set_bit (result, vi->id);
1034 /* If the result is not exactly at fieldoffset include the next
1035 field as well. See get_constraint_for_ptr_offset for more
1037 if (vi->offset != fieldoffset
1038 && vi->next != NULL)
1039 bitmap_set_bit (result, vi->next->id);
1043 bitmap_copy (set, result);
1044 BITMAP_FREE (result);
1047 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
1051 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1054 return bitmap_ior_into (to, from);
1060 tmp = BITMAP_ALLOC (&iteration_obstack);
1061 bitmap_copy (tmp, from);
1062 solution_set_add (tmp, inc);
1063 res = bitmap_ior_into (to, tmp);
1069 /* Insert constraint C into the list of complex constraints for graph
1073 insert_into_complex (constraint_graph_t graph,
1074 unsigned int var, constraint_t c)
1076 VEC (constraint_t, heap) *complex = graph->complex[var];
1077 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1080 /* Only insert constraints that do not already exist. */
1081 if (place >= VEC_length (constraint_t, complex)
1082 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1083 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1087 /* Condense two variable nodes into a single variable node, by moving
1088 all associated info from SRC to TO. */
1091 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1097 gcc_assert (find (from) == to);
1099 /* Move all complex constraints from src node into to node */
1100 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1102 /* In complex constraints for node src, we may have either
1103 a = *src, and *src = a, or an offseted constraint which are
1104 always added to the rhs node's constraints. */
1106 if (c->rhs.type == DEREF)
1108 else if (c->lhs.type == DEREF)
1113 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1114 VEC_free (constraint_t, heap, graph->complex[from]);
1115 graph->complex[from] = NULL;
1119 /* Remove edges involving NODE from GRAPH. */
1122 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1124 if (graph->succs[node])
1125 BITMAP_FREE (graph->succs[node]);
1128 /* Merge GRAPH nodes FROM and TO into node TO. */
1131 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1134 if (graph->indirect_cycles[from] != -1)
1136 /* If we have indirect cycles with the from node, and we have
1137 none on the to node, the to node has indirect cycles from the
1138 from node now that they are unified.
1139 If indirect cycles exist on both, unify the nodes that they
1140 are in a cycle with, since we know they are in a cycle with
1142 if (graph->indirect_cycles[to] == -1)
1143 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1146 /* Merge all the successor edges. */
1147 if (graph->succs[from])
1149 if (!graph->succs[to])
1150 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1151 bitmap_ior_into (graph->succs[to],
1152 graph->succs[from]);
1155 clear_edges_for_node (graph, from);
1159 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1160 it doesn't exist in the graph already. */
1163 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1169 if (!graph->implicit_preds[to])
1170 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1172 if (bitmap_set_bit (graph->implicit_preds[to], from))
1173 stats.num_implicit_edges++;
1176 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1177 it doesn't exist in the graph already.
1178 Return false if the edge already existed, true otherwise. */
1181 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1184 if (!graph->preds[to])
1185 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1186 bitmap_set_bit (graph->preds[to], from);
1189 /* Add a graph edge to GRAPH, going from FROM to TO if
1190 it doesn't exist in the graph already.
1191 Return false if the edge already existed, true otherwise. */
1194 add_graph_edge (constraint_graph_t graph, unsigned int to,
1205 if (!graph->succs[from])
1206 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1207 if (bitmap_set_bit (graph->succs[from], to))
1210 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1218 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1221 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1224 return (graph->succs[dest]
1225 && bitmap_bit_p (graph->succs[dest], src));
1228 /* Initialize the constraint graph structure to contain SIZE nodes. */
1231 init_graph (unsigned int size)
1235 graph = XCNEW (struct constraint_graph);
1237 graph->succs = XCNEWVEC (bitmap, graph->size);
1238 graph->indirect_cycles = XNEWVEC (int, graph->size);
1239 graph->rep = XNEWVEC (unsigned int, graph->size);
1240 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1241 graph->pe = XCNEWVEC (unsigned int, graph->size);
1242 graph->pe_rep = XNEWVEC (int, graph->size);
1244 for (j = 0; j < graph->size; j++)
1247 graph->pe_rep[j] = -1;
1248 graph->indirect_cycles[j] = -1;
1252 /* Build the constraint graph, adding only predecessor edges right now. */
1255 build_pred_graph (void)
1261 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1262 graph->preds = XCNEWVEC (bitmap, graph->size);
1263 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1264 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1265 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1266 graph->points_to = XCNEWVEC (bitmap, graph->size);
1267 graph->eq_rep = XNEWVEC (int, graph->size);
1268 graph->direct_nodes = sbitmap_alloc (graph->size);
1269 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1270 sbitmap_zero (graph->direct_nodes);
1272 for (j = 0; j < FIRST_REF_NODE; j++)
1274 if (!get_varinfo (j)->is_special_var)
1275 SET_BIT (graph->direct_nodes, j);
1278 for (j = 0; j < graph->size; j++)
1279 graph->eq_rep[j] = -1;
1281 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1282 graph->indirect_cycles[j] = -1;
1284 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1286 struct constraint_expr lhs = c->lhs;
1287 struct constraint_expr rhs = c->rhs;
1288 unsigned int lhsvar = lhs.var;
1289 unsigned int rhsvar = rhs.var;
1291 if (lhs.type == DEREF)
1294 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1295 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1297 else if (rhs.type == DEREF)
1300 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1301 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1303 RESET_BIT (graph->direct_nodes, lhsvar);
1305 else if (rhs.type == ADDRESSOF)
1310 if (graph->points_to[lhsvar] == NULL)
1311 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1312 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1314 if (graph->pointed_by[rhsvar] == NULL)
1315 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1316 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1318 /* Implicitly, *x = y */
1319 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1321 /* All related variables are no longer direct nodes. */
1322 RESET_BIT (graph->direct_nodes, rhsvar);
1323 v = get_varinfo (rhsvar);
1324 if (!v->is_full_var)
1326 v = lookup_vi_for_tree (v->decl);
1329 RESET_BIT (graph->direct_nodes, v->id);
1334 bitmap_set_bit (graph->address_taken, rhsvar);
1336 else if (lhsvar > anything_id
1337 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1340 add_pred_graph_edge (graph, lhsvar, rhsvar);
1341 /* Implicitly, *x = *y */
1342 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1343 FIRST_REF_NODE + rhsvar);
1345 else if (lhs.offset != 0 || rhs.offset != 0)
1347 if (rhs.offset != 0)
1348 RESET_BIT (graph->direct_nodes, lhs.var);
1349 else if (lhs.offset != 0)
1350 RESET_BIT (graph->direct_nodes, rhs.var);
1355 /* Build the constraint graph, adding successor edges. */
1358 build_succ_graph (void)
1363 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1365 struct constraint_expr lhs;
1366 struct constraint_expr rhs;
1367 unsigned int lhsvar;
1368 unsigned int rhsvar;
1375 lhsvar = find (lhs.var);
1376 rhsvar = find (rhs.var);
1378 if (lhs.type == DEREF)
1380 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1381 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1383 else if (rhs.type == DEREF)
1385 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1386 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1388 else if (rhs.type == ADDRESSOF)
1391 gcc_assert (find (rhs.var) == rhs.var);
1392 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1394 else if (lhsvar > anything_id
1395 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1397 add_graph_edge (graph, lhsvar, rhsvar);
1401 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1402 receive pointers. */
1403 t = find (storedanything_id);
1404 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1406 if (!TEST_BIT (graph->direct_nodes, i)
1407 && get_varinfo (i)->may_have_pointers)
1408 add_graph_edge (graph, find (i), t);
1411 /* Everything stored to ANYTHING also potentially escapes. */
1412 add_graph_edge (graph, find (escaped_id), t);
1416 /* Changed variables on the last iteration. */
1417 static unsigned int changed_count;
1418 static sbitmap changed;
1420 /* Strongly Connected Component visitation info. */
1427 unsigned int *node_mapping;
1429 VEC(unsigned,heap) *scc_stack;
1433 /* Recursive routine to find strongly connected components in GRAPH.
1434 SI is the SCC info to store the information in, and N is the id of current
1435 graph node we are processing.
1437 This is Tarjan's strongly connected component finding algorithm, as
1438 modified by Nuutila to keep only non-root nodes on the stack.
1439 The algorithm can be found in "On finding the strongly connected
1440 connected components in a directed graph" by Esko Nuutila and Eljas
1441 Soisalon-Soininen, in Information Processing Letters volume 49,
1442 number 1, pages 9-14. */
1445 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1449 unsigned int my_dfs;
1451 SET_BIT (si->visited, n);
1452 si->dfs[n] = si->current_index ++;
1453 my_dfs = si->dfs[n];
1455 /* Visit all the successors. */
1456 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1460 if (i > LAST_REF_NODE)
1464 if (TEST_BIT (si->deleted, w))
1467 if (!TEST_BIT (si->visited, w))
1468 scc_visit (graph, si, w);
1470 unsigned int t = find (w);
1471 unsigned int nnode = find (n);
1472 gcc_assert (nnode == n);
1474 if (si->dfs[t] < si->dfs[nnode])
1475 si->dfs[n] = si->dfs[t];
1479 /* See if any components have been identified. */
1480 if (si->dfs[n] == my_dfs)
1482 if (VEC_length (unsigned, si->scc_stack) > 0
1483 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1485 bitmap scc = BITMAP_ALLOC (NULL);
1486 unsigned int lowest_node;
1489 bitmap_set_bit (scc, n);
1491 while (VEC_length (unsigned, si->scc_stack) != 0
1492 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1494 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1496 bitmap_set_bit (scc, w);
1499 lowest_node = bitmap_first_set_bit (scc);
1500 gcc_assert (lowest_node < FIRST_REF_NODE);
1502 /* Collapse the SCC nodes into a single node, and mark the
1504 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1506 if (i < FIRST_REF_NODE)
1508 if (unite (lowest_node, i))
1509 unify_nodes (graph, lowest_node, i, false);
1513 unite (lowest_node, i);
1514 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1518 SET_BIT (si->deleted, n);
1521 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1524 /* Unify node FROM into node TO, updating the changed count if
1525 necessary when UPDATE_CHANGED is true. */
1528 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1529 bool update_changed)
1532 gcc_assert (to != from && find (to) == to);
1533 if (dump_file && (dump_flags & TDF_DETAILS))
1534 fprintf (dump_file, "Unifying %s to %s\n",
1535 get_varinfo (from)->name,
1536 get_varinfo (to)->name);
1539 stats.unified_vars_dynamic++;
1541 stats.unified_vars_static++;
1543 merge_graph_nodes (graph, to, from);
1544 merge_node_constraints (graph, to, from);
1546 /* Mark TO as changed if FROM was changed. If TO was already marked
1547 as changed, decrease the changed count. */
1549 if (update_changed && TEST_BIT (changed, from))
1551 RESET_BIT (changed, from);
1552 if (!TEST_BIT (changed, to))
1553 SET_BIT (changed, to);
1556 gcc_assert (changed_count > 0);
1560 if (get_varinfo (from)->solution)
1562 /* If the solution changes because of the merging, we need to mark
1563 the variable as changed. */
1564 if (bitmap_ior_into (get_varinfo (to)->solution,
1565 get_varinfo (from)->solution))
1567 if (update_changed && !TEST_BIT (changed, to))
1569 SET_BIT (changed, to);
1574 BITMAP_FREE (get_varinfo (from)->solution);
1575 BITMAP_FREE (get_varinfo (from)->oldsolution);
1577 if (stats.iterations > 0)
1579 BITMAP_FREE (get_varinfo (to)->oldsolution);
1580 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1583 if (valid_graph_edge (graph, to, to))
1585 if (graph->succs[to])
1586 bitmap_clear_bit (graph->succs[to], to);
1590 /* Information needed to compute the topological ordering of a graph. */
1594 /* sbitmap of visited nodes. */
1596 /* Array that stores the topological order of the graph, *in
1598 VEC(unsigned,heap) *topo_order;
1602 /* Initialize and return a topological info structure. */
1604 static struct topo_info *
1605 init_topo_info (void)
1607 size_t size = graph->size;
1608 struct topo_info *ti = XNEW (struct topo_info);
1609 ti->visited = sbitmap_alloc (size);
1610 sbitmap_zero (ti->visited);
1611 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1616 /* Free the topological sort info pointed to by TI. */
1619 free_topo_info (struct topo_info *ti)
1621 sbitmap_free (ti->visited);
1622 VEC_free (unsigned, heap, ti->topo_order);
1626 /* Visit the graph in topological order, and store the order in the
1627 topo_info structure. */
1630 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1636 SET_BIT (ti->visited, n);
1638 if (graph->succs[n])
1639 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1641 if (!TEST_BIT (ti->visited, j))
1642 topo_visit (graph, ti, j);
1645 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1648 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1649 starting solution for y. */
1652 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1655 unsigned int lhs = c->lhs.var;
1657 bitmap sol = get_varinfo (lhs)->solution;
1660 HOST_WIDE_INT roffset = c->rhs.offset;
1662 /* Our IL does not allow this. */
1663 gcc_assert (c->lhs.offset == 0);
1665 /* If the solution of Y contains anything it is good enough to transfer
1667 if (bitmap_bit_p (delta, anything_id))
1669 flag |= bitmap_set_bit (sol, anything_id);
1673 /* If we do not know at with offset the rhs is dereferenced compute
1674 the reachability set of DELTA, conservatively assuming it is
1675 dereferenced at all valid offsets. */
1676 if (roffset == UNKNOWN_OFFSET)
1678 solution_set_expand (delta, delta);
1679 /* No further offset processing is necessary. */
1683 /* For each variable j in delta (Sol(y)), add
1684 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1685 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1687 varinfo_t v = get_varinfo (j);
1688 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1692 fieldoffset = v->offset;
1693 else if (roffset != 0)
1694 v = first_vi_for_offset (v, fieldoffset);
1695 /* If the access is outside of the variable we can ignore it. */
1703 /* Adding edges from the special vars is pointless.
1704 They don't have sets that can change. */
1705 if (get_varinfo (t)->is_special_var)
1706 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1707 /* Merging the solution from ESCAPED needlessly increases
1708 the set. Use ESCAPED as representative instead. */
1709 else if (v->id == escaped_id)
1710 flag |= bitmap_set_bit (sol, escaped_id);
1711 else if (v->may_have_pointers
1712 && add_graph_edge (graph, lhs, t))
1713 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1715 /* If the variable is not exactly at the requested offset
1716 we have to include the next one. */
1717 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1722 fieldoffset = v->offset;
1728 /* If the LHS solution changed, mark the var as changed. */
1731 get_varinfo (lhs)->solution = sol;
1732 if (!TEST_BIT (changed, lhs))
1734 SET_BIT (changed, lhs);
1740 /* Process a constraint C that represents *(x + off) = y using DELTA
1741 as the starting solution for x. */
1744 do_ds_constraint (constraint_t c, bitmap delta)
1746 unsigned int rhs = c->rhs.var;
1747 bitmap sol = get_varinfo (rhs)->solution;
1750 HOST_WIDE_INT loff = c->lhs.offset;
1751 bool escaped_p = false;
1753 /* Our IL does not allow this. */
1754 gcc_assert (c->rhs.offset == 0);
1756 /* If the solution of y contains ANYTHING simply use the ANYTHING
1757 solution. This avoids needlessly increasing the points-to sets. */
1758 if (bitmap_bit_p (sol, anything_id))
1759 sol = get_varinfo (find (anything_id))->solution;
1761 /* If the solution for x contains ANYTHING we have to merge the
1762 solution of y into all pointer variables which we do via
1764 if (bitmap_bit_p (delta, anything_id))
1766 unsigned t = find (storedanything_id);
1767 if (add_graph_edge (graph, t, rhs))
1769 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1771 if (!TEST_BIT (changed, t))
1773 SET_BIT (changed, t);
1781 /* If we do not know at with offset the rhs is dereferenced compute
1782 the reachability set of DELTA, conservatively assuming it is
1783 dereferenced at all valid offsets. */
1784 if (loff == UNKNOWN_OFFSET)
1786 solution_set_expand (delta, delta);
1790 /* For each member j of delta (Sol(x)), add an edge from y to j and
1791 union Sol(y) into Sol(j) */
1792 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1794 varinfo_t v = get_varinfo (j);
1796 HOST_WIDE_INT fieldoffset = v->offset + loff;
1799 fieldoffset = v->offset;
1801 v = first_vi_for_offset (v, fieldoffset);
1802 /* If the access is outside of the variable we can ignore it. */
1808 if (v->may_have_pointers)
1810 /* If v is a global variable then this is an escape point. */
1811 if (v->is_global_var
1814 t = find (escaped_id);
1815 if (add_graph_edge (graph, t, rhs)
1816 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1817 && !TEST_BIT (changed, t))
1819 SET_BIT (changed, t);
1822 /* Enough to let rhs escape once. */
1826 if (v->is_special_var)
1830 if (add_graph_edge (graph, t, rhs)
1831 && bitmap_ior_into (get_varinfo (t)->solution, sol)
1832 && !TEST_BIT (changed, t))
1834 SET_BIT (changed, t);
1839 /* If the variable is not exactly at the requested offset
1840 we have to include the next one. */
1841 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1846 fieldoffset = v->offset;
1852 /* Handle a non-simple (simple meaning requires no iteration),
1853 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1856 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1858 if (c->lhs.type == DEREF)
1860 if (c->rhs.type == ADDRESSOF)
1867 do_ds_constraint (c, delta);
1870 else if (c->rhs.type == DEREF)
1873 if (!(get_varinfo (c->lhs.var)->is_special_var))
1874 do_sd_constraint (graph, c, delta);
1882 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1883 solution = get_varinfo (c->rhs.var)->solution;
1884 tmp = get_varinfo (c->lhs.var)->solution;
1886 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1890 get_varinfo (c->lhs.var)->solution = tmp;
1891 if (!TEST_BIT (changed, c->lhs.var))
1893 SET_BIT (changed, c->lhs.var);
1900 /* Initialize and return a new SCC info structure. */
1902 static struct scc_info *
1903 init_scc_info (size_t size)
1905 struct scc_info *si = XNEW (struct scc_info);
1908 si->current_index = 0;
1909 si->visited = sbitmap_alloc (size);
1910 sbitmap_zero (si->visited);
1911 si->deleted = sbitmap_alloc (size);
1912 sbitmap_zero (si->deleted);
1913 si->node_mapping = XNEWVEC (unsigned int, size);
1914 si->dfs = XCNEWVEC (unsigned int, size);
1916 for (i = 0; i < size; i++)
1917 si->node_mapping[i] = i;
1919 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1923 /* Free an SCC info structure pointed to by SI */
1926 free_scc_info (struct scc_info *si)
1928 sbitmap_free (si->visited);
1929 sbitmap_free (si->deleted);
1930 free (si->node_mapping);
1932 VEC_free (unsigned, heap, si->scc_stack);
1937 /* Find indirect cycles in GRAPH that occur, using strongly connected
1938 components, and note them in the indirect cycles map.
1940 This technique comes from Ben Hardekopf and Calvin Lin,
1941 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1942 Lines of Code", submitted to PLDI 2007. */
1945 find_indirect_cycles (constraint_graph_t graph)
1948 unsigned int size = graph->size;
1949 struct scc_info *si = init_scc_info (size);
1951 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1952 if (!TEST_BIT (si->visited, i) && find (i) == i)
1953 scc_visit (graph, si, i);
1958 /* Compute a topological ordering for GRAPH, and store the result in the
1959 topo_info structure TI. */
1962 compute_topo_order (constraint_graph_t graph,
1963 struct topo_info *ti)
1966 unsigned int size = graph->size;
1968 for (i = 0; i != size; ++i)
1969 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1970 topo_visit (graph, ti, i);
1973 /* Structure used to for hash value numbering of pointer equivalence
1976 typedef struct equiv_class_label
1979 unsigned int equivalence_class;
1981 } *equiv_class_label_t;
1982 typedef const struct equiv_class_label *const_equiv_class_label_t;
1984 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1986 static htab_t pointer_equiv_class_table;
1988 /* A hashtable for mapping a bitmap of labels->location equivalence
1990 static htab_t location_equiv_class_table;
1992 /* Hash function for a equiv_class_label_t */
1995 equiv_class_label_hash (const void *p)
1997 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1998 return ecl->hashcode;
2001 /* Equality function for two equiv_class_label_t's. */
2004 equiv_class_label_eq (const void *p1, const void *p2)
2006 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
2007 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
2008 return (eql1->hashcode == eql2->hashcode
2009 && bitmap_equal_p (eql1->labels, eql2->labels));
2012 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
2016 equiv_class_lookup (htab_t table, bitmap labels)
2019 struct equiv_class_label ecl;
2021 ecl.labels = labels;
2022 ecl.hashcode = bitmap_hash (labels);
2024 slot = htab_find_slot_with_hash (table, &ecl,
2025 ecl.hashcode, NO_INSERT);
2029 return ((equiv_class_label_t) *slot)->equivalence_class;
2033 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
2037 equiv_class_add (htab_t table, unsigned int equivalence_class,
2041 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
2043 ecl->labels = labels;
2044 ecl->equivalence_class = equivalence_class;
2045 ecl->hashcode = bitmap_hash (labels);
2047 slot = htab_find_slot_with_hash (table, ecl,
2048 ecl->hashcode, INSERT);
2049 gcc_assert (!*slot);
2050 *slot = (void *) ecl;
2053 /* Perform offline variable substitution.
2055 This is a worst case quadratic time way of identifying variables
2056 that must have equivalent points-to sets, including those caused by
2057 static cycles, and single entry subgraphs, in the constraint graph.
2059 The technique is described in "Exploiting Pointer and Location
2060 Equivalence to Optimize Pointer Analysis. In the 14th International
2061 Static Analysis Symposium (SAS), August 2007." It is known as the
2062 "HU" algorithm, and is equivalent to value numbering the collapsed
2063 constraint graph including evaluating unions.
2065 The general method of finding equivalence classes is as follows:
2066 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
2067 Initialize all non-REF nodes to be direct nodes.
2068 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
2070 For each constraint containing the dereference, we also do the same
2073 We then compute SCC's in the graph and unify nodes in the same SCC,
2076 For each non-collapsed node x:
2077 Visit all unvisited explicit incoming edges.
2078 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
2080 Lookup the equivalence class for pts(x).
2081 If we found one, equivalence_class(x) = found class.
2082 Otherwise, equivalence_class(x) = new class, and new_class is
2083 added to the lookup table.
2085 All direct nodes with the same equivalence class can be replaced
2086 with a single representative node.
2087 All unlabeled nodes (label == 0) are not pointers and all edges
2088 involving them can be eliminated.
2089 We perform these optimizations during rewrite_constraints
2091 In addition to pointer equivalence class finding, we also perform
2092 location equivalence class finding. This is the set of variables
2093 that always appear together in points-to sets. We use this to
2094 compress the size of the points-to sets. */
2096 /* Current maximum pointer equivalence class id. */
2097 static int pointer_equiv_class;
2099 /* Current maximum location equivalence class id. */
2100 static int location_equiv_class;
2102 /* Recursive routine to find strongly connected components in GRAPH,
2103 and label it's nodes with DFS numbers. */
2106 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2110 unsigned int my_dfs;
2112 gcc_assert (si->node_mapping[n] == n);
2113 SET_BIT (si->visited, n);
2114 si->dfs[n] = si->current_index ++;
2115 my_dfs = si->dfs[n];
2117 /* Visit all the successors. */
2118 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2120 unsigned int w = si->node_mapping[i];
2122 if (TEST_BIT (si->deleted, w))
2125 if (!TEST_BIT (si->visited, w))
2126 condense_visit (graph, si, w);
2128 unsigned int t = si->node_mapping[w];
2129 unsigned int nnode = si->node_mapping[n];
2130 gcc_assert (nnode == n);
2132 if (si->dfs[t] < si->dfs[nnode])
2133 si->dfs[n] = si->dfs[t];
2137 /* Visit all the implicit predecessors. */
2138 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2140 unsigned int w = si->node_mapping[i];
2142 if (TEST_BIT (si->deleted, w))
2145 if (!TEST_BIT (si->visited, w))
2146 condense_visit (graph, si, w);
2148 unsigned int t = si->node_mapping[w];
2149 unsigned int nnode = si->node_mapping[n];
2150 gcc_assert (nnode == n);
2152 if (si->dfs[t] < si->dfs[nnode])
2153 si->dfs[n] = si->dfs[t];
2157 /* See if any components have been identified. */
2158 if (si->dfs[n] == my_dfs)
2160 while (VEC_length (unsigned, si->scc_stack) != 0
2161 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2163 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2164 si->node_mapping[w] = n;
2166 if (!TEST_BIT (graph->direct_nodes, w))
2167 RESET_BIT (graph->direct_nodes, n);
2169 /* Unify our nodes. */
2170 if (graph->preds[w])
2172 if (!graph->preds[n])
2173 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2174 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2176 if (graph->implicit_preds[w])
2178 if (!graph->implicit_preds[n])
2179 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2180 bitmap_ior_into (graph->implicit_preds[n],
2181 graph->implicit_preds[w]);
2183 if (graph->points_to[w])
2185 if (!graph->points_to[n])
2186 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2187 bitmap_ior_into (graph->points_to[n],
2188 graph->points_to[w]);
2191 SET_BIT (si->deleted, n);
2194 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2197 /* Label pointer equivalences. */
2200 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2204 SET_BIT (si->visited, n);
2206 if (!graph->points_to[n])
2207 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2209 /* Label and union our incoming edges's points to sets. */
2210 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2212 unsigned int w = si->node_mapping[i];
2213 if (!TEST_BIT (si->visited, w))
2214 label_visit (graph, si, w);
2216 /* Skip unused edges */
2217 if (w == n || graph->pointer_label[w] == 0)
2220 if (graph->points_to[w])
2221 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2223 /* Indirect nodes get fresh variables. */
2224 if (!TEST_BIT (graph->direct_nodes, n))
2225 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2227 if (!bitmap_empty_p (graph->points_to[n]))
2229 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2230 graph->points_to[n]);
2233 label = pointer_equiv_class++;
2234 equiv_class_add (pointer_equiv_class_table,
2235 label, graph->points_to[n]);
2237 graph->pointer_label[n] = label;
2241 /* Perform offline variable substitution, discovering equivalence
2242 classes, and eliminating non-pointer variables. */
2244 static struct scc_info *
2245 perform_var_substitution (constraint_graph_t graph)
2248 unsigned int size = graph->size;
2249 struct scc_info *si = init_scc_info (size);
2251 bitmap_obstack_initialize (&iteration_obstack);
2252 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2253 equiv_class_label_eq, free);
2254 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2255 equiv_class_label_eq, free);
2256 pointer_equiv_class = 1;
2257 location_equiv_class = 1;
2259 /* Condense the nodes, which means to find SCC's, count incoming
2260 predecessors, and unite nodes in SCC's. */
2261 for (i = 0; i < FIRST_REF_NODE; i++)
2262 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2263 condense_visit (graph, si, si->node_mapping[i]);
2265 sbitmap_zero (si->visited);
2266 /* Actually the label the nodes for pointer equivalences */
2267 for (i = 0; i < FIRST_REF_NODE; i++)
2268 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2269 label_visit (graph, si, si->node_mapping[i]);
2271 /* Calculate location equivalence labels. */
2272 for (i = 0; i < FIRST_REF_NODE; i++)
2279 if (!graph->pointed_by[i])
2281 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2283 /* Translate the pointed-by mapping for pointer equivalence
2285 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2287 bitmap_set_bit (pointed_by,
2288 graph->pointer_label[si->node_mapping[j]]);
2290 /* The original pointed_by is now dead. */
2291 BITMAP_FREE (graph->pointed_by[i]);
2293 /* Look up the location equivalence label if one exists, or make
2295 label = equiv_class_lookup (location_equiv_class_table,
2299 label = location_equiv_class++;
2300 equiv_class_add (location_equiv_class_table,
2305 if (dump_file && (dump_flags & TDF_DETAILS))
2306 fprintf (dump_file, "Found location equivalence for node %s\n",
2307 get_varinfo (i)->name);
2308 BITMAP_FREE (pointed_by);
2310 graph->loc_label[i] = label;
2314 if (dump_file && (dump_flags & TDF_DETAILS))
2315 for (i = 0; i < FIRST_REF_NODE; i++)
2317 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2319 "Equivalence classes for %s node id %d:%s are pointer: %d"
2321 direct_node ? "Direct node" : "Indirect node", i,
2322 get_varinfo (i)->name,
2323 graph->pointer_label[si->node_mapping[i]],
2324 graph->loc_label[si->node_mapping[i]]);
2327 /* Quickly eliminate our non-pointer variables. */
2329 for (i = 0; i < FIRST_REF_NODE; i++)
2331 unsigned int node = si->node_mapping[i];
2333 if (graph->pointer_label[node] == 0)
2335 if (dump_file && (dump_flags & TDF_DETAILS))
2337 "%s is a non-pointer variable, eliminating edges.\n",
2338 get_varinfo (node)->name);
2339 stats.nonpointer_vars++;
2340 clear_edges_for_node (graph, node);
2347 /* Free information that was only necessary for variable
2351 free_var_substitution_info (struct scc_info *si)
2354 free (graph->pointer_label);
2355 free (graph->loc_label);
2356 free (graph->pointed_by);
2357 free (graph->points_to);
2358 free (graph->eq_rep);
2359 sbitmap_free (graph->direct_nodes);
2360 htab_delete (pointer_equiv_class_table);
2361 htab_delete (location_equiv_class_table);
2362 bitmap_obstack_release (&iteration_obstack);
2365 /* Return an existing node that is equivalent to NODE, which has
2366 equivalence class LABEL, if one exists. Return NODE otherwise. */
2369 find_equivalent_node (constraint_graph_t graph,
2370 unsigned int node, unsigned int label)
2372 /* If the address version of this variable is unused, we can
2373 substitute it for anything else with the same label.
2374 Otherwise, we know the pointers are equivalent, but not the
2375 locations, and we can unite them later. */
2377 if (!bitmap_bit_p (graph->address_taken, node))
2379 gcc_assert (label < graph->size);
2381 if (graph->eq_rep[label] != -1)
2383 /* Unify the two variables since we know they are equivalent. */
2384 if (unite (graph->eq_rep[label], node))
2385 unify_nodes (graph, graph->eq_rep[label], node, false);
2386 return graph->eq_rep[label];
2390 graph->eq_rep[label] = node;
2391 graph->pe_rep[label] = node;
2396 gcc_assert (label < graph->size);
2397 graph->pe[node] = label;
2398 if (graph->pe_rep[label] == -1)
2399 graph->pe_rep[label] = node;
2405 /* Unite pointer equivalent but not location equivalent nodes in
2406 GRAPH. This may only be performed once variable substitution is
2410 unite_pointer_equivalences (constraint_graph_t graph)
2414 /* Go through the pointer equivalences and unite them to their
2415 representative, if they aren't already. */
2416 for (i = 0; i < FIRST_REF_NODE; i++)
2418 unsigned int label = graph->pe[i];
2421 int label_rep = graph->pe_rep[label];
2423 if (label_rep == -1)
2426 label_rep = find (label_rep);
2427 if (label_rep >= 0 && unite (label_rep, find (i)))
2428 unify_nodes (graph, label_rep, i, false);
2433 /* Move complex constraints to the GRAPH nodes they belong to. */
2436 move_complex_constraints (constraint_graph_t graph)
2441 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2445 struct constraint_expr lhs = c->lhs;
2446 struct constraint_expr rhs = c->rhs;
2448 if (lhs.type == DEREF)
2450 insert_into_complex (graph, lhs.var, c);
2452 else if (rhs.type == DEREF)
2454 if (!(get_varinfo (lhs.var)->is_special_var))
2455 insert_into_complex (graph, rhs.var, c);
2457 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2458 && (lhs.offset != 0 || rhs.offset != 0))
2460 insert_into_complex (graph, rhs.var, c);
2467 /* Optimize and rewrite complex constraints while performing
2468 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2469 result of perform_variable_substitution. */
2472 rewrite_constraints (constraint_graph_t graph,
2473 struct scc_info *si)
2479 for (j = 0; j < graph->size; j++)
2480 gcc_assert (find (j) == j);
2482 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2484 struct constraint_expr lhs = c->lhs;
2485 struct constraint_expr rhs = c->rhs;
2486 unsigned int lhsvar = find (lhs.var);
2487 unsigned int rhsvar = find (rhs.var);
2488 unsigned int lhsnode, rhsnode;
2489 unsigned int lhslabel, rhslabel;
2491 lhsnode = si->node_mapping[lhsvar];
2492 rhsnode = si->node_mapping[rhsvar];
2493 lhslabel = graph->pointer_label[lhsnode];
2494 rhslabel = graph->pointer_label[rhsnode];
2496 /* See if it is really a non-pointer variable, and if so, ignore
2500 if (dump_file && (dump_flags & TDF_DETAILS))
2503 fprintf (dump_file, "%s is a non-pointer variable,"
2504 "ignoring constraint:",
2505 get_varinfo (lhs.var)->name);
2506 dump_constraint (dump_file, c);
2508 VEC_replace (constraint_t, constraints, i, NULL);
2514 if (dump_file && (dump_flags & TDF_DETAILS))
2517 fprintf (dump_file, "%s is a non-pointer variable,"
2518 "ignoring constraint:",
2519 get_varinfo (rhs.var)->name);
2520 dump_constraint (dump_file, c);
2522 VEC_replace (constraint_t, constraints, i, NULL);
2526 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2527 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2528 c->lhs.var = lhsvar;
2529 c->rhs.var = rhsvar;
2534 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2535 part of an SCC, false otherwise. */
2538 eliminate_indirect_cycles (unsigned int node)
2540 if (graph->indirect_cycles[node] != -1
2541 && !bitmap_empty_p (get_varinfo (node)->solution))
2544 VEC(unsigned,heap) *queue = NULL;
2546 unsigned int to = find (graph->indirect_cycles[node]);
2549 /* We can't touch the solution set and call unify_nodes
2550 at the same time, because unify_nodes is going to do
2551 bitmap unions into it. */
2553 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2555 if (find (i) == i && i != to)
2558 VEC_safe_push (unsigned, heap, queue, i);
2563 VEC_iterate (unsigned, queue, queuepos, i);
2566 unify_nodes (graph, to, i, true);
2568 VEC_free (unsigned, heap, queue);
2574 /* Solve the constraint graph GRAPH using our worklist solver.
2575 This is based on the PW* family of solvers from the "Efficient Field
2576 Sensitive Pointer Analysis for C" paper.
2577 It works by iterating over all the graph nodes, processing the complex
2578 constraints and propagating the copy constraints, until everything stops
2579 changed. This corresponds to steps 6-8 in the solving list given above. */
2582 solve_graph (constraint_graph_t graph)
2584 unsigned int size = graph->size;
2589 changed = sbitmap_alloc (size);
2590 sbitmap_zero (changed);
2592 /* Mark all initial non-collapsed nodes as changed. */
2593 for (i = 0; i < size; i++)
2595 varinfo_t ivi = get_varinfo (i);
2596 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2597 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2598 || VEC_length (constraint_t, graph->complex[i]) > 0))
2600 SET_BIT (changed, i);
2605 /* Allocate a bitmap to be used to store the changed bits. */
2606 pts = BITMAP_ALLOC (&pta_obstack);
2608 while (changed_count > 0)
2611 struct topo_info *ti = init_topo_info ();
2614 bitmap_obstack_initialize (&iteration_obstack);
2616 compute_topo_order (graph, ti);
2618 while (VEC_length (unsigned, ti->topo_order) != 0)
2621 i = VEC_pop (unsigned, ti->topo_order);
2623 /* If this variable is not a representative, skip it. */
2627 /* In certain indirect cycle cases, we may merge this
2628 variable to another. */
2629 if (eliminate_indirect_cycles (i) && find (i) != i)
2632 /* If the node has changed, we need to process the
2633 complex constraints and outgoing edges again. */
2634 if (TEST_BIT (changed, i))
2639 VEC(constraint_t,heap) *complex = graph->complex[i];
2640 bool solution_empty;
2642 RESET_BIT (changed, i);
2645 /* Compute the changed set of solution bits. */
2646 bitmap_and_compl (pts, get_varinfo (i)->solution,
2647 get_varinfo (i)->oldsolution);
2649 if (bitmap_empty_p (pts))
2652 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2654 solution = get_varinfo (i)->solution;
2655 solution_empty = bitmap_empty_p (solution);
2657 /* Process the complex constraints */
2658 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2660 /* XXX: This is going to unsort the constraints in
2661 some cases, which will occasionally add duplicate
2662 constraints during unification. This does not
2663 affect correctness. */
2664 c->lhs.var = find (c->lhs.var);
2665 c->rhs.var = find (c->rhs.var);
2667 /* The only complex constraint that can change our
2668 solution to non-empty, given an empty solution,
2669 is a constraint where the lhs side is receiving
2670 some set from elsewhere. */
2671 if (!solution_empty || c->lhs.type != DEREF)
2672 do_complex_constraint (graph, c, pts);
2675 solution_empty = bitmap_empty_p (solution);
2677 if (!solution_empty)
2680 unsigned eff_escaped_id = find (escaped_id);
2682 /* Propagate solution to all successors. */
2683 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2689 unsigned int to = find (j);
2690 tmp = get_varinfo (to)->solution;
2693 /* Don't try to propagate to ourselves. */
2697 /* If we propagate from ESCAPED use ESCAPED as
2699 if (i == eff_escaped_id)
2700 flag = bitmap_set_bit (tmp, escaped_id);
2702 flag = set_union_with_increment (tmp, pts, 0);
2706 get_varinfo (to)->solution = tmp;
2707 if (!TEST_BIT (changed, to))
2709 SET_BIT (changed, to);
2717 free_topo_info (ti);
2718 bitmap_obstack_release (&iteration_obstack);
2722 sbitmap_free (changed);
2723 bitmap_obstack_release (&oldpta_obstack);
2726 /* Map from trees to variable infos. */
2727 static struct pointer_map_t *vi_for_tree;
2730 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2733 insert_vi_for_tree (tree t, varinfo_t vi)
2735 void **slot = pointer_map_insert (vi_for_tree, t);
2737 gcc_assert (*slot == NULL);
2741 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2742 exist in the map, return NULL, otherwise, return the varinfo we found. */
2745 lookup_vi_for_tree (tree t)
2747 void **slot = pointer_map_contains (vi_for_tree, t);
2751 return (varinfo_t) *slot;
2754 /* Return a printable name for DECL */
2757 alias_get_name (tree decl)
2761 int num_printed = 0;
2763 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2764 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2766 res= get_name (decl);
2774 if (TREE_CODE (decl) == SSA_NAME)
2776 num_printed = asprintf (&temp, "%s_%u",
2777 alias_get_name (SSA_NAME_VAR (decl)),
2778 SSA_NAME_VERSION (decl));
2780 else if (DECL_P (decl))
2782 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2784 if (num_printed > 0)
2786 res = ggc_strdup (temp);
2792 /* Find the variable id for tree T in the map.
2793 If T doesn't exist in the map, create an entry for it and return it. */
2796 get_vi_for_tree (tree t)
2798 void **slot = pointer_map_contains (vi_for_tree, t);
2800 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2802 return (varinfo_t) *slot;
2805 /* Get a scalar constraint expression for a new temporary variable. */
2807 static struct constraint_expr
2808 new_scalar_tmp_constraint_exp (const char *name)
2810 struct constraint_expr tmp;
2813 vi = new_var_info (NULL_TREE, name);
2817 vi->is_full_var = 1;
2826 /* Get a constraint expression vector from an SSA_VAR_P node.
2827 If address_p is true, the result will be taken its address of. */
2830 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2832 struct constraint_expr cexpr;
2835 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2836 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2838 /* For parameters, get at the points-to set for the actual parm
2840 if (TREE_CODE (t) == SSA_NAME
2841 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2842 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2843 && SSA_NAME_IS_DEFAULT_DEF (t))
2845 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2849 vi = get_vi_for_tree (t);
2851 cexpr.type = SCALAR;
2853 /* If we determine the result is "anything", and we know this is readonly,
2854 say it points to readonly memory instead. */
2855 if (cexpr.var == anything_id && TREE_READONLY (t))
2858 cexpr.type = ADDRESSOF;
2859 cexpr.var = readonly_id;
2862 /* If we are not taking the address of the constraint expr, add all
2863 sub-fiels of the variable as well. */
2865 && !vi->is_full_var)
2867 for (; vi; vi = vi->next)
2870 VEC_safe_push (ce_s, heap, *results, &cexpr);
2875 VEC_safe_push (ce_s, heap, *results, &cexpr);
2878 /* Process constraint T, performing various simplifications and then
2879 adding it to our list of overall constraints. */
2882 process_constraint (constraint_t t)
2884 struct constraint_expr rhs = t->rhs;
2885 struct constraint_expr lhs = t->lhs;
2887 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2888 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2890 /* If we didn't get any useful constraint from the lhs we get
2891 &ANYTHING as fallback from get_constraint_for. Deal with
2892 it here by turning it into *ANYTHING. */
2893 if (lhs.type == ADDRESSOF
2894 && lhs.var == anything_id)
2897 /* ADDRESSOF on the lhs is invalid. */
2898 gcc_assert (lhs.type != ADDRESSOF);
2900 /* We shouldn't add constraints from things that cannot have pointers.
2901 It's not completely trivial to avoid in the callers, so do it here. */
2902 if (rhs.type != ADDRESSOF
2903 && !get_varinfo (rhs.var)->may_have_pointers)
2906 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2907 if (!get_varinfo (lhs.var)->may_have_pointers)
2910 /* This can happen in our IR with things like n->a = *p */
2911 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2913 /* Split into tmp = *rhs, *lhs = tmp */
2914 struct constraint_expr tmplhs;
2915 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2916 process_constraint (new_constraint (tmplhs, rhs));
2917 process_constraint (new_constraint (lhs, tmplhs));
2919 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2921 /* Split into tmp = &rhs, *lhs = tmp */
2922 struct constraint_expr tmplhs;
2923 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2924 process_constraint (new_constraint (tmplhs, rhs));
2925 process_constraint (new_constraint (lhs, tmplhs));
2929 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2930 VEC_safe_push (constraint_t, heap, constraints, t);
2934 /* Return true if T is a type that could contain pointers. */
2937 type_could_have_pointers (tree type)
2939 if (POINTER_TYPE_P (type))
2942 if (TREE_CODE (type) == ARRAY_TYPE)
2943 return type_could_have_pointers (TREE_TYPE (type));
2945 /* A function or method can consume pointers.
2946 ??? We could be more precise here. */
2947 if (TREE_CODE (type) == FUNCTION_TYPE
2948 || TREE_CODE (type) == METHOD_TYPE)
2951 return AGGREGATE_TYPE_P (type);
2954 /* Return true if T is a variable of a type that could contain
2958 could_have_pointers (tree t)
2960 return (((TREE_CODE (t) == VAR_DECL
2961 || TREE_CODE (t) == PARM_DECL
2962 || TREE_CODE (t) == RESULT_DECL)
2963 && (TREE_PUBLIC (t) || DECL_EXTERNAL (t) || TREE_ADDRESSABLE (t)))
2964 || type_could_have_pointers (TREE_TYPE (t)));
2967 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2970 static HOST_WIDE_INT
2971 bitpos_of_field (const tree fdecl)
2974 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2975 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2978 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2979 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2983 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2984 resulting constraint expressions in *RESULTS. */
2987 get_constraint_for_ptr_offset (tree ptr, tree offset,
2988 VEC (ce_s, heap) **results)
2990 struct constraint_expr c;
2992 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2994 /* If we do not do field-sensitive PTA adding offsets to pointers
2995 does not change the points-to solution. */
2996 if (!use_field_sensitive)
2998 get_constraint_for_rhs (ptr, results);
3002 /* If the offset is not a non-negative integer constant that fits
3003 in a HOST_WIDE_INT, we have to fall back to a conservative
3004 solution which includes all sub-fields of all pointed-to
3005 variables of ptr. */
3006 if (offset == NULL_TREE
3007 || !host_integerp (offset, 0))
3008 rhsoffset = UNKNOWN_OFFSET;
3011 /* Make sure the bit-offset also fits. */
3012 rhsunitoffset = TREE_INT_CST_LOW (offset);
3013 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
3014 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
3015 rhsoffset = UNKNOWN_OFFSET;
3018 get_constraint_for_rhs (ptr, results);
3022 /* As we are eventually appending to the solution do not use
3023 VEC_iterate here. */
3024 n = VEC_length (ce_s, *results);
3025 for (j = 0; j < n; j++)
3028 c = *VEC_index (ce_s, *results, j);
3029 curr = get_varinfo (c.var);
3031 if (c.type == ADDRESSOF
3032 /* If this varinfo represents a full variable just use it. */
3033 && curr->is_full_var)
3035 else if (c.type == ADDRESSOF
3036 /* If we do not know the offset add all subfields. */
3037 && rhsoffset == UNKNOWN_OFFSET)
3039 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3042 struct constraint_expr c2;
3044 c2.type = ADDRESSOF;
3046 if (c2.var != c.var)
3047 VEC_safe_push (ce_s, heap, *results, &c2);
3052 else if (c.type == ADDRESSOF)
3055 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3057 /* Search the sub-field which overlaps with the
3058 pointed-to offset. If the result is outside of the variable
3059 we have to provide a conservative result, as the variable is
3060 still reachable from the resulting pointer (even though it
3061 technically cannot point to anything). The last and first
3062 sub-fields are such conservative results.
3063 ??? If we always had a sub-field for &object + 1 then
3064 we could represent this in a more precise way. */
3066 && curr->offset < offset)
3068 temp = first_or_preceding_vi_for_offset (curr, offset);
3070 /* If the found variable is not exactly at the pointed to
3071 result, we have to include the next variable in the
3072 solution as well. Otherwise two increments by offset / 2
3073 do not result in the same or a conservative superset
3075 if (temp->offset != offset
3076 && temp->next != NULL)
3078 struct constraint_expr c2;
3079 c2.var = temp->next->id;
3080 c2.type = ADDRESSOF;
3082 VEC_safe_push (ce_s, heap, *results, &c2);
3088 c.offset = rhsoffset;
3090 VEC_replace (ce_s, *results, j, &c);
3095 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3096 If address_p is true the result will be taken its address of.
3097 If lhs_p is true then the constraint expression is assumed to be used
3101 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3102 bool address_p, bool lhs_p)
3105 HOST_WIDE_INT bitsize = -1;
3106 HOST_WIDE_INT bitmaxsize = -1;
3107 HOST_WIDE_INT bitpos;
3109 struct constraint_expr *result;
3111 /* Some people like to do cute things like take the address of
3114 while (handled_component_p (forzero)
3115 || INDIRECT_REF_P (forzero)
3116 || TREE_CODE (forzero) == MEM_REF)
3117 forzero = TREE_OPERAND (forzero, 0);
3119 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3121 struct constraint_expr temp;
3124 temp.var = integer_id;
3126 VEC_safe_push (ce_s, heap, *results, &temp);
3130 /* Handle type-punning through unions. If we are extracting a pointer
3131 from a union via a possibly type-punning access that pointer
3132 points to anything, similar to a conversion of an integer to
3138 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3139 u = TREE_OPERAND (u, 0))
3140 if (TREE_CODE (u) == COMPONENT_REF
3141 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3143 struct constraint_expr temp;
3146 temp.var = anything_id;
3147 temp.type = ADDRESSOF;
3148 VEC_safe_push (ce_s, heap, *results, &temp);
3153 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3155 /* Pretend to take the address of the base, we'll take care of
3156 adding the required subset of sub-fields below. */
3157 get_constraint_for_1 (t, results, true, lhs_p);
3158 gcc_assert (VEC_length (ce_s, *results) == 1);
3159 result = VEC_last (ce_s, *results);
3161 if (result->type == SCALAR
3162 && get_varinfo (result->var)->is_full_var)
3163 /* For single-field vars do not bother about the offset. */
3165 else if (result->type == SCALAR)
3167 /* In languages like C, you can access one past the end of an
3168 array. You aren't allowed to dereference it, so we can
3169 ignore this constraint. When we handle pointer subtraction,
3170 we may have to do something cute here. */
3172 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3175 /* It's also not true that the constraint will actually start at the
3176 right offset, it may start in some padding. We only care about
3177 setting the constraint to the first actual field it touches, so
3179 struct constraint_expr cexpr = *result;
3181 VEC_pop (ce_s, *results);
3183 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3185 if (ranges_overlap_p (curr->offset, curr->size,
3186 bitpos, bitmaxsize))
3188 cexpr.var = curr->id;
3189 VEC_safe_push (ce_s, heap, *results, &cexpr);
3194 /* If we are going to take the address of this field then
3195 to be able to compute reachability correctly add at least
3196 the last field of the variable. */
3198 && VEC_length (ce_s, *results) == 0)
3200 curr = get_varinfo (cexpr.var);
3201 while (curr->next != NULL)
3203 cexpr.var = curr->id;
3204 VEC_safe_push (ce_s, heap, *results, &cexpr);
3206 else if (VEC_length (ce_s, *results) == 0)
3207 /* Assert that we found *some* field there. The user couldn't be
3208 accessing *only* padding. */
3209 /* Still the user could access one past the end of an array
3210 embedded in a struct resulting in accessing *only* padding. */
3211 /* Or accessing only padding via type-punning to a type
3212 that has a filed just in padding space. */
3214 cexpr.type = SCALAR;
3215 cexpr.var = anything_id;
3217 VEC_safe_push (ce_s, heap, *results, &cexpr);
3220 else if (bitmaxsize == 0)
3222 if (dump_file && (dump_flags & TDF_DETAILS))
3223 fprintf (dump_file, "Access to zero-sized part of variable,"
3227 if (dump_file && (dump_flags & TDF_DETAILS))
3228 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3230 else if (result->type == DEREF)
3232 /* If we do not know exactly where the access goes say so. Note
3233 that only for non-structure accesses we know that we access
3234 at most one subfiled of any variable. */
3236 || bitsize != bitmaxsize
3237 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3238 || result->offset == UNKNOWN_OFFSET)
3239 result->offset = UNKNOWN_OFFSET;
3241 result->offset += bitpos;
3243 else if (result->type == ADDRESSOF)
3245 /* We can end up here for component references on a
3246 VIEW_CONVERT_EXPR <>(&foobar). */
3247 result->type = SCALAR;
3248 result->var = anything_id;
3256 /* Dereference the constraint expression CONS, and return the result.
3257 DEREF (ADDRESSOF) = SCALAR
3258 DEREF (SCALAR) = DEREF
3259 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3260 This is needed so that we can handle dereferencing DEREF constraints. */
3263 do_deref (VEC (ce_s, heap) **constraints)
3265 struct constraint_expr *c;
3268 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3270 if (c->type == SCALAR)
3272 else if (c->type == ADDRESSOF)
3274 else if (c->type == DEREF)
3276 struct constraint_expr tmplhs;
3277 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3278 process_constraint (new_constraint (tmplhs, *c));
3279 c->var = tmplhs.var;
3286 /* Given a tree T, return the constraint expression for taking the
3290 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3292 struct constraint_expr *c;
3295 get_constraint_for_1 (t, results, true, true);
3297 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3299 if (c->type == DEREF)
3302 c->type = ADDRESSOF;
3306 /* Given a tree T, return the constraint expression for it. */
3309 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3312 struct constraint_expr temp;
3314 /* x = integer is all glommed to a single variable, which doesn't
3315 point to anything by itself. That is, of course, unless it is an
3316 integer constant being treated as a pointer, in which case, we
3317 will return that this is really the addressof anything. This
3318 happens below, since it will fall into the default case. The only
3319 case we know something about an integer treated like a pointer is
3320 when it is the NULL pointer, and then we just say it points to
3323 Do not do that if -fno-delete-null-pointer-checks though, because
3324 in that case *NULL does not fail, so it _should_ alias *anything.
3325 It is not worth adding a new option or renaming the existing one,
3326 since this case is relatively obscure. */
3327 if ((TREE_CODE (t) == INTEGER_CST
3328 && integer_zerop (t))
3329 /* The only valid CONSTRUCTORs in gimple with pointer typed
3330 elements are zero-initializer. But in IPA mode we also
3331 process global initializers, so verify at least. */
3332 || (TREE_CODE (t) == CONSTRUCTOR
3333 && CONSTRUCTOR_NELTS (t) == 0))
3335 if (flag_delete_null_pointer_checks)
3336 temp.var = nothing_id;
3338 temp.var = nonlocal_id;
3339 temp.type = ADDRESSOF;
3341 VEC_safe_push (ce_s, heap, *results, &temp);
3345 /* String constants are read-only. */
3346 if (TREE_CODE (t) == STRING_CST)
3348 temp.var = readonly_id;
3351 VEC_safe_push (ce_s, heap, *results, &temp);
3355 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3357 case tcc_expression:
3359 switch (TREE_CODE (t))
3362 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3370 switch (TREE_CODE (t))
3374 tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
3375 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
3380 case ARRAY_RANGE_REF:
3382 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3384 case VIEW_CONVERT_EXPR:
3385 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3388 /* We are missing handling for TARGET_MEM_REF here. */
3393 case tcc_exceptional:
3395 switch (TREE_CODE (t))
3399 get_constraint_for_ssa_var (t, results, address_p);
3406 VEC (ce_s, heap) *tmp = NULL;
3407 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3409 struct constraint_expr *rhsp;
3411 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3412 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3413 VEC_safe_push (ce_s, heap, *results, rhsp);
3414 VEC_truncate (ce_s, tmp, 0);
3416 VEC_free (ce_s, heap, tmp);
3417 /* We do not know whether the constructor was complete,
3418 so technically we have to add &NOTHING or &ANYTHING
3419 like we do for an empty constructor as well. */
3426 case tcc_declaration:
3428 get_constraint_for_ssa_var (t, results, address_p);
3433 /* We cannot refer to automatic variables through constants. */
3434 temp.type = ADDRESSOF;
3435 temp.var = nonlocal_id;
3437 VEC_safe_push (ce_s, heap, *results, &temp);
3443 /* The default fallback is a constraint from anything. */
3444 temp.type = ADDRESSOF;
3445 temp.var = anything_id;
3447 VEC_safe_push (ce_s, heap, *results, &temp);
3450 /* Given a gimple tree T, return the constraint expression vector for it. */
3453 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3455 gcc_assert (VEC_length (ce_s, *results) == 0);
3457 get_constraint_for_1 (t, results, false, true);
3460 /* Given a gimple tree T, return the constraint expression vector for it
3461 to be used as the rhs of a constraint. */
3464 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3466 gcc_assert (VEC_length (ce_s, *results) == 0);
3468 get_constraint_for_1 (t, results, false, false);
3472 /* Efficiently generates constraints from all entries in *RHSC to all
3473 entries in *LHSC. */
3476 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3478 struct constraint_expr *lhsp, *rhsp;
3481 if (VEC_length (ce_s, lhsc) <= 1
3482 || VEC_length (ce_s, rhsc) <= 1)
3484 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3485 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3486 process_constraint (new_constraint (*lhsp, *rhsp));
3490 struct constraint_expr tmp;
3491 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3492 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3493 process_constraint (new_constraint (tmp, *rhsp));
3494 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3495 process_constraint (new_constraint (*lhsp, tmp));
3499 /* Handle aggregate copies by expanding into copies of the respective
3500 fields of the structures. */
3503 do_structure_copy (tree lhsop, tree rhsop)
3505 struct constraint_expr *lhsp, *rhsp;
3506 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3509 get_constraint_for (lhsop, &lhsc);
3510 get_constraint_for_rhs (rhsop, &rhsc);
3511 lhsp = VEC_index (ce_s, lhsc, 0);
3512 rhsp = VEC_index (ce_s, rhsc, 0);
3513 if (lhsp->type == DEREF
3514 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3515 || rhsp->type == DEREF)
3517 if (lhsp->type == DEREF)
3519 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3520 lhsp->offset = UNKNOWN_OFFSET;
3522 if (rhsp->type == DEREF)
3524 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3525 rhsp->offset = UNKNOWN_OFFSET;
3527 process_all_all_constraints (lhsc, rhsc);
3529 else if (lhsp->type == SCALAR
3530 && (rhsp->type == SCALAR
3531 || rhsp->type == ADDRESSOF))
3533 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3534 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3536 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3537 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3538 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3540 varinfo_t lhsv, rhsv;
3541 rhsp = VEC_index (ce_s, rhsc, k);
3542 lhsv = get_varinfo (lhsp->var);
3543 rhsv = get_varinfo (rhsp->var);
3544 if (lhsv->may_have_pointers
3545 && ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3546 rhsv->offset + lhsoffset, rhsv->size))
3547 process_constraint (new_constraint (*lhsp, *rhsp));
3548 if (lhsv->offset + rhsoffset + lhsv->size
3549 > rhsv->offset + lhsoffset + rhsv->size)
3552 if (k >= VEC_length (ce_s, rhsc))
3562 VEC_free (ce_s, heap, lhsc);
3563 VEC_free (ce_s, heap, rhsc);
3566 /* Create constraints ID = { rhsc }. */
3569 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3571 struct constraint_expr *c;
3572 struct constraint_expr includes;
3576 includes.offset = 0;
3577 includes.type = SCALAR;
3579 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3580 process_constraint (new_constraint (includes, *c));
3583 /* Create a constraint ID = OP. */
3586 make_constraint_to (unsigned id, tree op)
3588 VEC(ce_s, heap) *rhsc = NULL;
3589 get_constraint_for_rhs (op, &rhsc);
3590 make_constraints_to (id, rhsc);
3591 VEC_free (ce_s, heap, rhsc);
3594 /* Create a constraint ID = &FROM. */
3597 make_constraint_from (varinfo_t vi, int from)
3599 struct constraint_expr lhs, rhs;
3607 rhs.type = ADDRESSOF;
3608 process_constraint (new_constraint (lhs, rhs));
3611 /* Create a constraint ID = FROM. */
3614 make_copy_constraint (varinfo_t vi, int from)
3616 struct constraint_expr lhs, rhs;
3625 process_constraint (new_constraint (lhs, rhs));
3628 /* Make constraints necessary to make OP escape. */
3631 make_escape_constraint (tree op)
3633 make_constraint_to (escaped_id, op);
3636 /* Add constraints to that the solution of VI is transitively closed. */
3639 make_transitive_closure_constraints (varinfo_t vi)
3641 struct constraint_expr lhs, rhs;
3650 process_constraint (new_constraint (lhs, rhs));
3652 /* VAR = VAR + UNKNOWN; */
3658 rhs.offset = UNKNOWN_OFFSET;
3659 process_constraint (new_constraint (lhs, rhs));
3662 /* Create a new artificial heap variable with NAME.
3663 Return the created variable. */
3666 make_heapvar_for (varinfo_t lhs, const char *name)
3669 tree heapvar = heapvar_lookup (lhs->decl, lhs->offset);
3671 if (heapvar == NULL_TREE)
3674 heapvar = create_tmp_var_raw (ptr_type_node, name);
3675 DECL_EXTERNAL (heapvar) = 1;
3677 heapvar_insert (lhs->decl, lhs->offset, heapvar);
3679 ann = get_var_ann (heapvar);
3680 ann->is_heapvar = 1;
3683 /* For global vars we need to add a heapvar to the list of referenced
3684 vars of a different function than it was created for originally. */
3685 if (cfun && gimple_referenced_vars (cfun))
3686 add_referenced_var (heapvar);
3688 vi = new_var_info (heapvar, name);
3689 vi->is_artificial_var = true;
3690 vi->is_heap_var = true;
3691 vi->is_unknown_size_var = true;
3695 vi->is_full_var = true;
3696 insert_vi_for_tree (heapvar, vi);
3701 /* Create a new artificial heap variable with NAME and make a
3702 constraint from it to LHS. Return the created variable. */
3705 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3707 varinfo_t vi = make_heapvar_for (lhs, name);
3708 make_constraint_from (lhs, vi->id);
3713 /* Create a new artificial heap variable with NAME and make a
3714 constraint from it to LHS. Set flags according to a tag used
3715 for tracking restrict pointers. */
3718 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3721 vi = make_constraint_from_heapvar (lhs, name);
3722 vi->is_restrict_var = 1;
3723 vi->is_global_var = 0;
3724 vi->is_special_var = 1;
3725 vi->may_have_pointers = 0;
3728 /* In IPA mode there are varinfos for different aspects of reach
3729 function designator. One for the points-to set of the return
3730 value, one for the variables that are clobbered by the function,
3731 one for its uses and one for each parameter (including a single
3732 glob for remaining variadic arguments). */
3734 enum { fi_clobbers = 1, fi_uses = 2,
3735 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3737 /* Get a constraint for the requested part of a function designator FI
3738 when operating in IPA mode. */
3740 static struct constraint_expr
3741 get_function_part_constraint (varinfo_t fi, unsigned part)
3743 struct constraint_expr c;
3745 gcc_assert (in_ipa_mode);
3747 if (fi->id == anything_id)
3749 /* ??? We probably should have a ANYFN special variable. */
3750 c.var = anything_id;
3754 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3756 varinfo_t ai = first_vi_for_offset (fi, part);
3760 c.var = anything_id;
3774 /* For non-IPA mode, generate constraints necessary for a call on the
3778 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3780 struct constraint_expr rhsc;
3782 bool returns_uses = false;
3784 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3786 tree arg = gimple_call_arg (stmt, i);
3787 int flags = gimple_call_arg_flags (stmt, i);
3789 /* If the argument is not used or it does not contain pointers
3790 we can ignore it. */
3791 if ((flags & EAF_UNUSED)
3792 || !could_have_pointers (arg))
3795 /* As we compute ESCAPED context-insensitive we do not gain
3796 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3797 set. The argument would still get clobbered through the
3799 ??? We might get away with less (and more precise) constraints
3800 if using a temporary for transitively closing things. */
3801 if ((flags & EAF_NOCLOBBER)
3802 && (flags & EAF_NOESCAPE))
3804 varinfo_t uses = get_call_use_vi (stmt);
3805 if (!(flags & EAF_DIRECT))
3806 make_transitive_closure_constraints (uses);
3807 make_constraint_to (uses->id, arg);
3808 returns_uses = true;
3810 else if (flags & EAF_NOESCAPE)
3812 varinfo_t uses = get_call_use_vi (stmt);
3813 varinfo_t clobbers = get_call_clobber_vi (stmt);
3814 if (!(flags & EAF_DIRECT))
3816 make_transitive_closure_constraints (uses);
3817 make_transitive_closure_constraints (clobbers);
3819 make_constraint_to (uses->id, arg);
3820 make_constraint_to (clobbers->id, arg);
3821 returns_uses = true;
3824 make_escape_constraint (arg);
3827 /* If we added to the calls uses solution make sure we account for
3828 pointers to it to be returned. */
3831 rhsc.var = get_call_use_vi (stmt)->id;
3834 VEC_safe_push (ce_s, heap, *results, &rhsc);
3837 /* The static chain escapes as well. */
3838 if (gimple_call_chain (stmt))
3839 make_escape_constraint (gimple_call_chain (stmt));
3841 /* And if we applied NRV the address of the return slot escapes as well. */
3842 if (gimple_call_return_slot_opt_p (stmt)
3843 && gimple_call_lhs (stmt) != NULL_TREE
3844 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3846 VEC(ce_s, heap) *tmpc = NULL;
3847 struct constraint_expr lhsc, *c;
3848 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3849 lhsc.var = escaped_id;
3852 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3853 process_constraint (new_constraint (lhsc, *c));
3854 VEC_free(ce_s, heap, tmpc);
3857 /* Regular functions return nonlocal memory. */
3858 rhsc.var = nonlocal_id;
3861 VEC_safe_push (ce_s, heap, *results, &rhsc);
3864 /* For non-IPA mode, generate constraints necessary for a call
3865 that returns a pointer and assigns it to LHS. This simply makes
3866 the LHS point to global and escaped variables. */
3869 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3872 VEC(ce_s, heap) *lhsc = NULL;
3874 get_constraint_for (lhs, &lhsc);
3875 /* If the store is to a global decl make sure to
3876 add proper escape constraints. */
3877 lhs = get_base_address (lhs);
3880 && is_global_var (lhs))
3882 struct constraint_expr tmpc;
3883 tmpc.var = escaped_id;
3886 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3889 /* If the call returns an argument unmodified override the rhs
3891 flags = gimple_call_return_flags (stmt);
3892 if (flags & ERF_RETURNS_ARG
3893 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3897 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3898 get_constraint_for (arg, &rhsc);
3899 process_all_all_constraints (lhsc, rhsc);
3900 VEC_free (ce_s, heap, rhsc);
3902 else if (flags & ERF_NOALIAS)
3905 struct constraint_expr tmpc;
3907 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3908 /* We delay marking allocated storage global until we know if
3910 DECL_EXTERNAL (vi->decl) = 0;
3911 vi->is_global_var = 0;
3912 /* If this is not a real malloc call assume the memory was
3913 initialized and thus may point to global memory. All
3914 builtin functions with the malloc attribute behave in a sane way. */
3916 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3917 make_constraint_from (vi, nonlocal_id);
3920 tmpc.type = ADDRESSOF;
3921 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3924 process_all_all_constraints (lhsc, rhsc);
3926 VEC_free (ce_s, heap, lhsc);
3929 /* For non-IPA mode, generate constraints necessary for a call of a
3930 const function that returns a pointer in the statement STMT. */
3933 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3935 struct constraint_expr rhsc;
3938 /* Treat nested const functions the same as pure functions as far
3939 as the static chain is concerned. */
3940 if (gimple_call_chain (stmt))
3942 varinfo_t uses = get_call_use_vi (stmt);
3943 make_transitive_closure_constraints (uses);
3944 make_constraint_to (uses->id, gimple_call_chain (stmt));
3945 rhsc.var = uses->id;
3948 VEC_safe_push (ce_s, heap, *results, &rhsc);
3951 /* May return arguments. */
3952 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3954 tree arg = gimple_call_arg (stmt, k);
3956 if (could_have_pointers (arg))
3958 VEC(ce_s, heap) *argc = NULL;
3960 struct constraint_expr *argp;
3961 get_constraint_for_rhs (arg, &argc);
3962 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3963 VEC_safe_push (ce_s, heap, *results, argp);
3964 VEC_free(ce_s, heap, argc);
3968 /* May return addresses of globals. */
3969 rhsc.var = nonlocal_id;
3971 rhsc.type = ADDRESSOF;
3972 VEC_safe_push (ce_s, heap, *results, &rhsc);
3975 /* For non-IPA mode, generate constraints necessary for a call to a
3976 pure function in statement STMT. */
3979 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3981 struct constraint_expr rhsc;
3983 varinfo_t uses = NULL;
3985 /* Memory reached from pointer arguments is call-used. */
3986 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3988 tree arg = gimple_call_arg (stmt, i);
3990 if (could_have_pointers (arg))
3994 uses = get_call_use_vi (stmt);
3995 make_transitive_closure_constraints (uses);
3997 make_constraint_to (uses->id, arg);
4001 /* The static chain is used as well. */
4002 if (gimple_call_chain (stmt))
4006 uses = get_call_use_vi (stmt);
4007 make_transitive_closure_constraints (uses);
4009 make_constraint_to (uses->id, gimple_call_chain (stmt));
4012 /* Pure functions may return call-used and nonlocal memory. */
4015 rhsc.var = uses->id;
4018 VEC_safe_push (ce_s, heap, *results, &rhsc);
4020 rhsc.var = nonlocal_id;
4023 VEC_safe_push (ce_s, heap, *results, &rhsc);
4027 /* Return the varinfo for the callee of CALL. */
4030 get_fi_for_callee (gimple call)
4034 /* If we can directly resolve the function being called, do so.
4035 Otherwise, it must be some sort of indirect expression that
4036 we should still be able to handle. */
4037 decl = gimple_call_fndecl (call);
4039 return get_vi_for_tree (decl);
4041 decl = gimple_call_fn (call);
4042 /* The function can be either an SSA name pointer or,
4043 worse, an OBJ_TYPE_REF. In this case we have no
4044 clue and should be getting ANYFN (well, ANYTHING for now). */
4045 if (TREE_CODE (decl) == SSA_NAME)
4047 if (TREE_CODE (decl) == SSA_NAME
4048 && (TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
4049 || TREE_CODE (SSA_NAME_VAR (decl)) == RESULT_DECL)
4050 && SSA_NAME_IS_DEFAULT_DEF (decl))
4051 decl = SSA_NAME_VAR (decl);
4052 return get_vi_for_tree (decl);
4054 else if (TREE_CODE (decl) == INTEGER_CST
4055 || TREE_CODE (decl) == OBJ_TYPE_REF)
4056 return get_varinfo (anything_id);
4061 /* Walk statement T setting up aliasing constraints according to the
4062 references found in T. This function is the main part of the
4063 constraint builder. AI points to auxiliary alias information used
4064 when building alias sets and computing alias grouping heuristics. */
4067 find_func_aliases (gimple origt)
4070 VEC(ce_s, heap) *lhsc = NULL;
4071 VEC(ce_s, heap) *rhsc = NULL;
4072 struct constraint_expr *c;
4075 /* Now build constraints expressions. */
4076 if (gimple_code (t) == GIMPLE_PHI)
4078 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t))));
4080 /* Only care about pointers and structures containing
4082 if (could_have_pointers (gimple_phi_result (t)))
4087 /* For a phi node, assign all the arguments to
4089 get_constraint_for (gimple_phi_result (t), &lhsc);
4090 for (i = 0; i < gimple_phi_num_args (t); i++)
4092 tree strippedrhs = PHI_ARG_DEF (t, i);
4094 STRIP_NOPS (strippedrhs);
4095 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4097 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4099 struct constraint_expr *c2;
4100 while (VEC_length (ce_s, rhsc) > 0)
4102 c2 = VEC_last (ce_s, rhsc);
4103 process_constraint (new_constraint (*c, *c2));
4104 VEC_pop (ce_s, rhsc);
4110 /* In IPA mode, we need to generate constraints to pass call
4111 arguments through their calls. There are two cases,
4112 either a GIMPLE_CALL returning a value, or just a plain
4113 GIMPLE_CALL when we are not.
4115 In non-ipa mode, we need to generate constraints for each
4116 pointer passed by address. */
4117 else if (is_gimple_call (t))
4119 tree fndecl = gimple_call_fndecl (t);
4120 if (fndecl != NULL_TREE
4121 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4122 /* ??? All builtins that are handled here need to be handled
4123 in the alias-oracle query functions explicitly! */
4124 switch (DECL_FUNCTION_CODE (fndecl))
4126 /* All the following functions return a pointer to the same object
4127 as their first argument points to. The functions do not add
4128 to the ESCAPED solution. The functions make the first argument
4129 pointed to memory point to what the second argument pointed to
4130 memory points to. */
4131 case BUILT_IN_STRCPY:
4132 case BUILT_IN_STRNCPY:
4133 case BUILT_IN_BCOPY:
4134 case BUILT_IN_MEMCPY:
4135 case BUILT_IN_MEMMOVE:
4136 case BUILT_IN_MEMPCPY:
4137 case BUILT_IN_STPCPY:
4138 case BUILT_IN_STPNCPY:
4139 case BUILT_IN_STRCAT:
4140 case BUILT_IN_STRNCAT:
4142 tree res = gimple_call_lhs (t);
4143 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4144 == BUILT_IN_BCOPY ? 1 : 0));
4145 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4146 == BUILT_IN_BCOPY ? 0 : 1));
4147 if (res != NULL_TREE)
4149 get_constraint_for (res, &lhsc);
4150 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4151 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4152 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4153 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4155 get_constraint_for (dest, &rhsc);
4156 process_all_all_constraints (lhsc, rhsc);
4157 VEC_free (ce_s, heap, lhsc);
4158 VEC_free (ce_s, heap, rhsc);
4160 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4161 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4164 process_all_all_constraints (lhsc, rhsc);
4165 VEC_free (ce_s, heap, lhsc);
4166 VEC_free (ce_s, heap, rhsc);
4169 case BUILT_IN_MEMSET:
4171 tree res = gimple_call_lhs (t);
4172 tree dest = gimple_call_arg (t, 0);
4175 struct constraint_expr ac;
4176 if (res != NULL_TREE)
4178 get_constraint_for (res, &lhsc);
4179 get_constraint_for (dest, &rhsc);
4180 process_all_all_constraints (lhsc, rhsc);
4181 VEC_free (ce_s, heap, lhsc);
4182 VEC_free (ce_s, heap, rhsc);
4184 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4186 if (flag_delete_null_pointer_checks
4187 && integer_zerop (gimple_call_arg (t, 1)))
4189 ac.type = ADDRESSOF;
4190 ac.var = nothing_id;
4195 ac.var = integer_id;
4198 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4199 process_constraint (new_constraint (*lhsp, ac));
4200 VEC_free (ce_s, heap, lhsc);
4203 /* All the following functions do not return pointers, do not
4204 modify the points-to sets of memory reachable from their
4205 arguments and do not add to the ESCAPED solution. */
4206 case BUILT_IN_SINCOS:
4207 case BUILT_IN_SINCOSF:
4208 case BUILT_IN_SINCOSL:
4209 case BUILT_IN_FREXP:
4210 case BUILT_IN_FREXPF:
4211 case BUILT_IN_FREXPL:
4212 case BUILT_IN_GAMMA_R:
4213 case BUILT_IN_GAMMAF_R:
4214 case BUILT_IN_GAMMAL_R:
4215 case BUILT_IN_LGAMMA_R:
4216 case BUILT_IN_LGAMMAF_R:
4217 case BUILT_IN_LGAMMAL_R:
4219 case BUILT_IN_MODFF:
4220 case BUILT_IN_MODFL:
4221 case BUILT_IN_REMQUO:
4222 case BUILT_IN_REMQUOF:
4223 case BUILT_IN_REMQUOL:
4226 /* Trampolines are special - they set up passing the static
4228 case BUILT_IN_INIT_TRAMPOLINE:
4230 tree tramp = gimple_call_arg (t, 0);
4231 tree nfunc = gimple_call_arg (t, 1);
4232 tree frame = gimple_call_arg (t, 2);
4234 struct constraint_expr lhs, *rhsp;
4237 varinfo_t nfi = NULL;
4238 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4239 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4242 lhs = get_function_part_constraint (nfi, fi_static_chain);
4243 get_constraint_for (frame, &rhsc);
4244 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4245 process_constraint (new_constraint (lhs, *rhsp));
4246 VEC_free (ce_s, heap, rhsc);
4248 /* Make the frame point to the function for
4249 the trampoline adjustment call. */
4250 get_constraint_for (tramp, &lhsc);
4252 get_constraint_for (nfunc, &rhsc);
4253 process_all_all_constraints (lhsc, rhsc);
4254 VEC_free (ce_s, heap, rhsc);
4255 VEC_free (ce_s, heap, lhsc);
4260 /* Else fallthru to generic handling which will let
4261 the frame escape. */
4264 case BUILT_IN_ADJUST_TRAMPOLINE:
4266 tree tramp = gimple_call_arg (t, 0);
4267 tree res = gimple_call_lhs (t);
4268 if (in_ipa_mode && res)
4270 get_constraint_for (res, &lhsc);
4271 get_constraint_for (tramp, &rhsc);
4273 process_all_all_constraints (lhsc, rhsc);
4274 VEC_free (ce_s, heap, rhsc);
4275 VEC_free (ce_s, heap, lhsc);
4279 /* Variadic argument handling needs to be handled in IPA
4281 case BUILT_IN_VA_START:
4285 tree valist = gimple_call_arg (t, 0);
4286 struct constraint_expr rhs, *lhsp;
4288 /* The va_list gets access to pointers in variadic
4290 fi = lookup_vi_for_tree (cfun->decl);
4291 gcc_assert (fi != NULL);
4292 get_constraint_for (valist, &lhsc);
4294 rhs = get_function_part_constraint (fi, ~0);
4295 rhs.type = ADDRESSOF;
4296 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4297 process_constraint (new_constraint (*lhsp, rhs));
4298 VEC_free (ce_s, heap, lhsc);
4299 /* va_list is clobbered. */
4300 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4305 /* va_end doesn't have any effect that matters. */
4306 case BUILT_IN_VA_END:
4308 /* Alternate return. Simply give up for now. */
4309 case BUILT_IN_RETURN:
4313 || !(fi = get_vi_for_tree (cfun->decl)))
4314 make_constraint_from (get_varinfo (escaped_id), anything_id);
4315 else if (in_ipa_mode
4318 struct constraint_expr lhs, rhs;
4319 lhs = get_function_part_constraint (fi, fi_result);
4320 rhs.var = anything_id;
4323 process_constraint (new_constraint (lhs, rhs));
4327 /* printf-style functions may have hooks to set pointers to
4328 point to somewhere into the generated string. Leave them
4329 for a later excercise... */
4331 /* Fallthru to general call handling. */;
4335 && (!(fi = lookup_vi_for_tree (fndecl))
4336 || !fi->is_fn_info)))
4338 VEC(ce_s, heap) *rhsc = NULL;
4339 int flags = gimple_call_flags (t);
4341 /* Const functions can return their arguments and addresses
4342 of global memory but not of escaped memory. */
4343 if (flags & (ECF_CONST|ECF_NOVOPS))
4345 if (gimple_call_lhs (t))
4346 handle_const_call (t, &rhsc);
4348 /* Pure functions can return addresses in and of memory
4349 reachable from their arguments, but they are not an escape
4350 point for reachable memory of their arguments. */
4351 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4352 handle_pure_call (t, &rhsc);
4354 handle_rhs_call (t, &rhsc);
4355 if (gimple_call_lhs (t))
4357 if (could_have_pointers (gimple_call_lhs (t)))
4358 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4359 /* Similar to conversions a result that is not a pointer
4360 is an escape point for any pointer the function might
4362 else if (flags & (ECF_CONST|ECF_PURE
4363 |ECF_NOVOPS|ECF_LOOPING_CONST_OR_PURE))
4364 make_constraints_to (escaped_id, rhsc);
4366 VEC_free (ce_s, heap, rhsc);
4373 fi = get_fi_for_callee (t);
4375 /* Assign all the passed arguments to the appropriate incoming
4376 parameters of the function. */
4377 for (j = 0; j < gimple_call_num_args (t); j++)
4379 struct constraint_expr lhs ;
4380 struct constraint_expr *rhsp;
4381 tree arg = gimple_call_arg (t, j);
4383 if (!could_have_pointers (arg))
4386 get_constraint_for_rhs (arg, &rhsc);
4387 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4388 while (VEC_length (ce_s, rhsc) != 0)
4390 rhsp = VEC_last (ce_s, rhsc);
4391 process_constraint (new_constraint (lhs, *rhsp));
4392 VEC_pop (ce_s, rhsc);
4396 /* If we are returning a value, assign it to the result. */
4397 lhsop = gimple_call_lhs (t);
4399 && type_could_have_pointers (TREE_TYPE (lhsop)))
4401 struct constraint_expr rhs;
4402 struct constraint_expr *lhsp;
4404 get_constraint_for (lhsop, &lhsc);
4405 rhs = get_function_part_constraint (fi, fi_result);
4407 && DECL_RESULT (fndecl)
4408 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4410 VEC(ce_s, heap) *tem = NULL;
4411 VEC_safe_push (ce_s, heap, tem, &rhs);
4413 rhs = *VEC_index (ce_s, tem, 0);
4414 VEC_free(ce_s, heap, tem);
4416 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4417 process_constraint (new_constraint (*lhsp, rhs));
4420 /* If we pass the result decl by reference, honor that. */
4423 && DECL_RESULT (fndecl)
4424 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4426 struct constraint_expr lhs;
4427 struct constraint_expr *rhsp;
4429 get_constraint_for_address_of (lhsop, &rhsc);
4430 lhs = get_function_part_constraint (fi, fi_result);
4431 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4432 process_constraint (new_constraint (lhs, *rhsp));
4433 VEC_free (ce_s, heap, rhsc);
4436 /* If we use a static chain, pass it along. */
4437 if (gimple_call_chain (t))
4439 struct constraint_expr lhs;
4440 struct constraint_expr *rhsp;
4442 get_constraint_for (gimple_call_chain (t), &rhsc);
4443 lhs = get_function_part_constraint (fi, fi_static_chain);
4444 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4445 process_constraint (new_constraint (lhs, *rhsp));
4449 /* Otherwise, just a regular assignment statement. Only care about
4450 operations with pointer result, others are dealt with as escape
4451 points if they have pointer operands. */
4452 else if (is_gimple_assign (t)
4453 && type_could_have_pointers (TREE_TYPE (gimple_assign_lhs (t))))
4455 /* Otherwise, just a regular assignment statement. */
4456 tree lhsop = gimple_assign_lhs (t);
4457 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4459 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4460 do_structure_copy (lhsop, rhsop);
4463 struct constraint_expr temp;
4464 get_constraint_for (lhsop, &lhsc);
4466 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4467 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4468 gimple_assign_rhs2 (t), &rhsc);
4469 else if (gimple_assign_rhs_code (t) == BIT_AND_EXPR
4470 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4472 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4473 the pointer. Handle it by offsetting it by UNKNOWN. */
4474 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4477 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4478 && !(POINTER_TYPE_P (gimple_expr_type (t))
4479 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4480 || gimple_assign_single_p (t))
4481 get_constraint_for_rhs (rhsop, &rhsc);
4484 temp.type = ADDRESSOF;
4485 temp.var = anything_id;
4487 VEC_safe_push (ce_s, heap, rhsc, &temp);
4489 process_all_all_constraints (lhsc, rhsc);
4491 /* If there is a store to a global variable the rhs escapes. */
4492 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4494 && is_global_var (lhsop)
4496 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4497 make_escape_constraint (rhsop);
4498 /* If this is a conversion of a non-restrict pointer to a
4499 restrict pointer track it with a new heapvar. */
4500 else if (gimple_assign_cast_p (t)
4501 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4502 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4503 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4504 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4505 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4508 /* For conversions of pointers to non-pointers the pointer escapes. */
4509 else if (gimple_assign_cast_p (t)
4510 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
4511 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
4513 make_escape_constraint (gimple_assign_rhs1 (t));
4515 /* Handle escapes through return. */
4516 else if (gimple_code (t) == GIMPLE_RETURN
4517 && gimple_return_retval (t) != NULL_TREE
4518 && could_have_pointers (gimple_return_retval (t)))
4522 || !(fi = get_vi_for_tree (cfun->decl)))
4523 make_escape_constraint (gimple_return_retval (t));
4524 else if (in_ipa_mode
4527 struct constraint_expr lhs ;
4528 struct constraint_expr *rhsp;
4531 lhs = get_function_part_constraint (fi, fi_result);
4532 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4533 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4534 process_constraint (new_constraint (lhs, *rhsp));
4537 /* Handle asms conservatively by adding escape constraints to everything. */
4538 else if (gimple_code (t) == GIMPLE_ASM)
4540 unsigned i, noutputs;
4541 const char **oconstraints;
4542 const char *constraint;
4543 bool allows_mem, allows_reg, is_inout;
4545 noutputs = gimple_asm_noutputs (t);
4546 oconstraints = XALLOCAVEC (const char *, noutputs);
4548 for (i = 0; i < noutputs; ++i)
4550 tree link = gimple_asm_output_op (t, i);
4551 tree op = TREE_VALUE (link);
4553 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4554 oconstraints[i] = constraint;
4555 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4556 &allows_reg, &is_inout);
4558 /* A memory constraint makes the address of the operand escape. */
4559 if (!allows_reg && allows_mem)
4560 make_escape_constraint (build_fold_addr_expr (op));
4562 /* The asm may read global memory, so outputs may point to
4563 any global memory. */
4564 if (op && could_have_pointers (op))
4566 VEC(ce_s, heap) *lhsc = NULL;
4567 struct constraint_expr rhsc, *lhsp;
4569 get_constraint_for (op, &lhsc);
4570 rhsc.var = nonlocal_id;
4573 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4574 process_constraint (new_constraint (*lhsp, rhsc));
4575 VEC_free (ce_s, heap, lhsc);
4578 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4580 tree link = gimple_asm_input_op (t, i);
4581 tree op = TREE_VALUE (link);
4583 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4585 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4586 &allows_mem, &allows_reg);
4588 /* A memory constraint makes the address of the operand escape. */
4589 if (!allows_reg && allows_mem)
4590 make_escape_constraint (build_fold_addr_expr (op));
4591 /* Strictly we'd only need the constraint to ESCAPED if
4592 the asm clobbers memory, otherwise using something
4593 along the lines of per-call clobbers/uses would be enough. */
4594 else if (op && could_have_pointers (op))
4595 make_escape_constraint (op);
4599 VEC_free (ce_s, heap, rhsc);
4600 VEC_free (ce_s, heap, lhsc);
4604 /* Create a constraint adding to the clobber set of FI the memory
4605 pointed to by PTR. */
4608 process_ipa_clobber (varinfo_t fi, tree ptr)
4610 VEC(ce_s, heap) *ptrc = NULL;
4611 struct constraint_expr *c, lhs;
4613 get_constraint_for_rhs (ptr, &ptrc);
4614 lhs = get_function_part_constraint (fi, fi_clobbers);
4615 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4616 process_constraint (new_constraint (lhs, *c));
4617 VEC_free (ce_s, heap, ptrc);
4620 /* Walk statement T setting up clobber and use constraints according to the
4621 references found in T. This function is a main part of the
4622 IPA constraint builder. */
4625 find_func_clobbers (gimple origt)
4628 VEC(ce_s, heap) *lhsc = NULL;
4629 VEC(ce_s, heap) *rhsc = NULL;
4632 /* Add constraints for clobbered/used in IPA mode.
4633 We are not interested in what automatic variables are clobbered
4634 or used as we only use the information in the caller to which
4635 they do not escape. */
4636 gcc_assert (in_ipa_mode);
4638 /* If the stmt refers to memory in any way it better had a VUSE. */
4639 if (gimple_vuse (t) == NULL_TREE)
4642 /* We'd better have function information for the current function. */
4643 fi = lookup_vi_for_tree (cfun->decl);
4644 gcc_assert (fi != NULL);
4646 /* Account for stores in assignments and calls. */
4647 if (gimple_vdef (t) != NULL_TREE
4648 && gimple_has_lhs (t))
4650 tree lhs = gimple_get_lhs (t);
4652 while (handled_component_p (tem))
4653 tem = TREE_OPERAND (tem, 0);
4655 && !auto_var_in_fn_p (tem, cfun->decl))
4656 || INDIRECT_REF_P (tem)
4657 || (TREE_CODE (tem) == MEM_REF
4658 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4660 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4662 struct constraint_expr lhsc, *rhsp;
4664 lhsc = get_function_part_constraint (fi, fi_clobbers);
4665 get_constraint_for_address_of (lhs, &rhsc);
4666 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4667 process_constraint (new_constraint (lhsc, *rhsp));
4668 VEC_free (ce_s, heap, rhsc);
4672 /* Account for uses in assigments and returns. */
4673 if (gimple_assign_single_p (t)
4674 || (gimple_code (t) == GIMPLE_RETURN
4675 && gimple_return_retval (t) != NULL_TREE))
4677 tree rhs = (gimple_assign_single_p (t)
4678 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4680 while (handled_component_p (tem))
4681 tem = TREE_OPERAND (tem, 0);
4683 && !auto_var_in_fn_p (tem, cfun->decl))
4684 || INDIRECT_REF_P (tem)
4685 || (TREE_CODE (tem) == MEM_REF
4686 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4688 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4690 struct constraint_expr lhs, *rhsp;
4692 lhs = get_function_part_constraint (fi, fi_uses);
4693 get_constraint_for_address_of (rhs, &rhsc);
4694 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4695 process_constraint (new_constraint (lhs, *rhsp));
4696 VEC_free (ce_s, heap, rhsc);
4700 if (is_gimple_call (t))
4702 varinfo_t cfi = NULL;
4703 tree decl = gimple_call_fndecl (t);
4704 struct constraint_expr lhs, rhs;
4707 /* For builtins we do not have separate function info. For those
4708 we do not generate escapes for we have to generate clobbers/uses. */
4710 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4711 switch (DECL_FUNCTION_CODE (decl))
4713 /* The following functions use and clobber memory pointed to
4714 by their arguments. */
4715 case BUILT_IN_STRCPY:
4716 case BUILT_IN_STRNCPY:
4717 case BUILT_IN_BCOPY:
4718 case BUILT_IN_MEMCPY:
4719 case BUILT_IN_MEMMOVE:
4720 case BUILT_IN_MEMPCPY:
4721 case BUILT_IN_STPCPY:
4722 case BUILT_IN_STPNCPY:
4723 case BUILT_IN_STRCAT:
4724 case BUILT_IN_STRNCAT:
4726 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4727 == BUILT_IN_BCOPY ? 1 : 0));
4728 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4729 == BUILT_IN_BCOPY ? 0 : 1));
4731 struct constraint_expr *rhsp, *lhsp;
4732 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4733 lhs = get_function_part_constraint (fi, fi_clobbers);
4734 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4735 process_constraint (new_constraint (lhs, *lhsp));
4736 VEC_free (ce_s, heap, lhsc);
4737 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4738 lhs = get_function_part_constraint (fi, fi_uses);
4739 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4740 process_constraint (new_constraint (lhs, *rhsp));
4741 VEC_free (ce_s, heap, rhsc);
4744 /* The following function clobbers memory pointed to by
4746 case BUILT_IN_MEMSET:
4748 tree dest = gimple_call_arg (t, 0);
4751 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4752 lhs = get_function_part_constraint (fi, fi_clobbers);
4753 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4754 process_constraint (new_constraint (lhs, *lhsp));
4755 VEC_free (ce_s, heap, lhsc);
4758 /* The following functions clobber their second and third
4760 case BUILT_IN_SINCOS:
4761 case BUILT_IN_SINCOSF:
4762 case BUILT_IN_SINCOSL:
4764 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4765 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4768 /* The following functions clobber their second argument. */
4769 case BUILT_IN_FREXP:
4770 case BUILT_IN_FREXPF:
4771 case BUILT_IN_FREXPL:
4772 case BUILT_IN_LGAMMA_R:
4773 case BUILT_IN_LGAMMAF_R:
4774 case BUILT_IN_LGAMMAL_R:
4775 case BUILT_IN_GAMMA_R:
4776 case BUILT_IN_GAMMAF_R:
4777 case BUILT_IN_GAMMAL_R:
4779 case BUILT_IN_MODFF:
4780 case BUILT_IN_MODFL:
4782 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4785 /* The following functions clobber their third argument. */
4786 case BUILT_IN_REMQUO:
4787 case BUILT_IN_REMQUOF:
4788 case BUILT_IN_REMQUOL:
4790 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4793 /* The following functions neither read nor clobber memory. */
4796 /* Trampolines are of no interest to us. */
4797 case BUILT_IN_INIT_TRAMPOLINE:
4798 case BUILT_IN_ADJUST_TRAMPOLINE:
4800 case BUILT_IN_VA_START:
4801 case BUILT_IN_VA_END:
4803 /* printf-style functions may have hooks to set pointers to
4804 point to somewhere into the generated string. Leave them
4805 for a later excercise... */
4807 /* Fallthru to general call handling. */;
4810 /* Parameters passed by value are used. */
4811 lhs = get_function_part_constraint (fi, fi_uses);
4812 for (i = 0; i < gimple_call_num_args (t); i++)
4814 struct constraint_expr *rhsp;
4815 tree arg = gimple_call_arg (t, i);
4817 if (TREE_CODE (arg) == SSA_NAME
4818 || is_gimple_min_invariant (arg))
4821 get_constraint_for_address_of (arg, &rhsc);
4822 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4823 process_constraint (new_constraint (lhs, *rhsp));
4824 VEC_free (ce_s, heap, rhsc);
4827 /* Build constraints for propagating clobbers/uses along the
4829 cfi = get_fi_for_callee (t);
4830 if (cfi->id == anything_id)
4832 if (gimple_vdef (t))
4833 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4835 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4840 /* For callees without function info (that's external functions),
4841 ESCAPED is clobbered and used. */
4842 if (gimple_call_fndecl (t)
4843 && !cfi->is_fn_info)
4847 if (gimple_vdef (t))
4848 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4850 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4852 /* Also honor the call statement use/clobber info. */
4853 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4854 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4856 if ((vi = lookup_call_use_vi (t)) != NULL)
4857 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4862 /* Otherwise the caller clobbers and uses what the callee does.
4863 ??? This should use a new complex constraint that filters
4864 local variables of the callee. */
4865 if (gimple_vdef (t))
4867 lhs = get_function_part_constraint (fi, fi_clobbers);
4868 rhs = get_function_part_constraint (cfi, fi_clobbers);
4869 process_constraint (new_constraint (lhs, rhs));
4871 lhs = get_function_part_constraint (fi, fi_uses);
4872 rhs = get_function_part_constraint (cfi, fi_uses);
4873 process_constraint (new_constraint (lhs, rhs));
4875 else if (gimple_code (t) == GIMPLE_ASM)
4877 /* ??? Ick. We can do better. */
4878 if (gimple_vdef (t))
4879 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4881 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4885 VEC_free (ce_s, heap, rhsc);
4889 /* Find the first varinfo in the same variable as START that overlaps with
4890 OFFSET. Return NULL if we can't find one. */
4893 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4895 /* If the offset is outside of the variable, bail out. */
4896 if (offset >= start->fullsize)
4899 /* If we cannot reach offset from start, lookup the first field
4900 and start from there. */
4901 if (start->offset > offset)
4902 start = lookup_vi_for_tree (start->decl);
4906 /* We may not find a variable in the field list with the actual
4907 offset when when we have glommed a structure to a variable.
4908 In that case, however, offset should still be within the size
4910 if (offset >= start->offset
4911 && (offset - start->offset) < start->size)
4920 /* Find the first varinfo in the same variable as START that overlaps with
4921 OFFSET. If there is no such varinfo the varinfo directly preceding
4922 OFFSET is returned. */
4925 first_or_preceding_vi_for_offset (varinfo_t start,
4926 unsigned HOST_WIDE_INT offset)
4928 /* If we cannot reach offset from start, lookup the first field
4929 and start from there. */
4930 if (start->offset > offset)
4931 start = lookup_vi_for_tree (start->decl);
4933 /* We may not find a variable in the field list with the actual
4934 offset when when we have glommed a structure to a variable.
4935 In that case, however, offset should still be within the size
4937 If we got beyond the offset we look for return the field
4938 directly preceding offset which may be the last field. */
4940 && offset >= start->offset
4941 && !((offset - start->offset) < start->size))
4942 start = start->next;
4948 /* This structure is used during pushing fields onto the fieldstack
4949 to track the offset of the field, since bitpos_of_field gives it
4950 relative to its immediate containing type, and we want it relative
4951 to the ultimate containing object. */
4955 /* Offset from the base of the base containing object to this field. */
4956 HOST_WIDE_INT offset;
4958 /* Size, in bits, of the field. */
4959 unsigned HOST_WIDE_INT size;
4961 unsigned has_unknown_size : 1;
4963 unsigned may_have_pointers : 1;
4965 unsigned only_restrict_pointers : 1;
4967 typedef struct fieldoff fieldoff_s;
4969 DEF_VEC_O(fieldoff_s);
4970 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4972 /* qsort comparison function for two fieldoff's PA and PB */
4975 fieldoff_compare (const void *pa, const void *pb)
4977 const fieldoff_s *foa = (const fieldoff_s *)pa;
4978 const fieldoff_s *fob = (const fieldoff_s *)pb;
4979 unsigned HOST_WIDE_INT foasize, fobsize;
4981 if (foa->offset < fob->offset)
4983 else if (foa->offset > fob->offset)
4986 foasize = foa->size;
4987 fobsize = fob->size;
4988 if (foasize < fobsize)
4990 else if (foasize > fobsize)
4995 /* Sort a fieldstack according to the field offset and sizes. */
4997 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4999 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
5002 /* Return true if V is a tree that we can have subvars for.
5003 Normally, this is any aggregate type. Also complex
5004 types which are not gimple registers can have subvars. */
5007 var_can_have_subvars (const_tree v)
5009 /* Volatile variables should never have subvars. */
5010 if (TREE_THIS_VOLATILE (v))
5013 /* Non decls or memory tags can never have subvars. */
5017 /* Aggregates without overlapping fields can have subvars. */
5018 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
5024 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5025 the fields of TYPE onto fieldstack, recording their offsets along
5028 OFFSET is used to keep track of the offset in this entire
5029 structure, rather than just the immediately containing structure.
5030 Returns false if the caller is supposed to handle the field we
5034 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5035 HOST_WIDE_INT offset, bool must_have_pointers_p)
5038 bool empty_p = true;
5040 if (TREE_CODE (type) != RECORD_TYPE)
5043 /* If the vector of fields is growing too big, bail out early.
5044 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5046 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5049 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5050 if (TREE_CODE (field) == FIELD_DECL)
5053 HOST_WIDE_INT foff = bitpos_of_field (field);
5055 if (!var_can_have_subvars (field)
5056 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5057 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5059 else if (!push_fields_onto_fieldstack
5060 (TREE_TYPE (field), fieldstack, offset + foff,
5061 must_have_pointers_p)
5062 && (DECL_SIZE (field)
5063 && !integer_zerop (DECL_SIZE (field))))
5064 /* Empty structures may have actual size, like in C++. So
5065 see if we didn't push any subfields and the size is
5066 nonzero, push the field onto the stack. */
5071 fieldoff_s *pair = NULL;
5072 bool has_unknown_size = false;
5074 if (!VEC_empty (fieldoff_s, *fieldstack))
5075 pair = VEC_last (fieldoff_s, *fieldstack);
5077 if (!DECL_SIZE (field)
5078 || !host_integerp (DECL_SIZE (field), 1))
5079 has_unknown_size = true;
5081 /* If adjacent fields do not contain pointers merge them. */
5083 && !pair->may_have_pointers
5084 && !pair->has_unknown_size
5085 && !has_unknown_size
5086 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff
5087 && !must_have_pointers_p
5088 && !could_have_pointers (field))
5090 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5094 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5095 pair->offset = offset + foff;
5096 pair->has_unknown_size = has_unknown_size;
5097 if (!has_unknown_size)
5098 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5101 pair->may_have_pointers
5102 = must_have_pointers_p || could_have_pointers (field);
5103 pair->only_restrict_pointers
5104 = (!has_unknown_size
5105 && POINTER_TYPE_P (TREE_TYPE (field))
5106 && TYPE_RESTRICT (TREE_TYPE (field)));
5116 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5117 if it is a varargs function. */
5120 count_num_arguments (tree decl, bool *is_varargs)
5122 unsigned int num = 0;
5125 /* Capture named arguments for K&R functions. They do not
5126 have a prototype and thus no TYPE_ARG_TYPES. */
5127 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5130 /* Check if the function has variadic arguments. */
5131 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5132 if (TREE_VALUE (t) == void_type_node)
5140 /* Creation function node for DECL, using NAME, and return the index
5141 of the variable we've created for the function. */
5144 create_function_info_for (tree decl, const char *name)
5146 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5147 varinfo_t vi, prev_vi;
5150 bool is_varargs = false;
5151 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5153 /* Create the variable info. */
5155 vi = new_var_info (decl, name);
5158 vi->fullsize = fi_parm_base + num_args;
5160 vi->may_have_pointers = false;
5163 insert_vi_for_tree (vi->decl, vi);
5167 /* Create a variable for things the function clobbers and one for
5168 things the function uses. */
5170 varinfo_t clobbervi, usevi;
5171 const char *newname;
5174 asprintf (&tempname, "%s.clobber", name);
5175 newname = ggc_strdup (tempname);
5178 clobbervi = new_var_info (NULL, newname);
5179 clobbervi->offset = fi_clobbers;
5180 clobbervi->size = 1;
5181 clobbervi->fullsize = vi->fullsize;
5182 clobbervi->is_full_var = true;
5183 clobbervi->is_global_var = false;
5184 gcc_assert (prev_vi->offset < clobbervi->offset);
5185 prev_vi->next = clobbervi;
5186 prev_vi = clobbervi;
5188 asprintf (&tempname, "%s.use", name);
5189 newname = ggc_strdup (tempname);
5192 usevi = new_var_info (NULL, newname);
5193 usevi->offset = fi_uses;
5195 usevi->fullsize = vi->fullsize;
5196 usevi->is_full_var = true;
5197 usevi->is_global_var = false;
5198 gcc_assert (prev_vi->offset < usevi->offset);
5199 prev_vi->next = usevi;
5203 /* And one for the static chain. */
5204 if (fn->static_chain_decl != NULL_TREE)
5207 const char *newname;
5210 asprintf (&tempname, "%s.chain", name);
5211 newname = ggc_strdup (tempname);
5214 chainvi = new_var_info (fn->static_chain_decl, newname);
5215 chainvi->offset = fi_static_chain;
5217 chainvi->fullsize = vi->fullsize;
5218 chainvi->is_full_var = true;
5219 chainvi->is_global_var = false;
5220 gcc_assert (prev_vi->offset < chainvi->offset);
5221 prev_vi->next = chainvi;
5223 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5226 /* Create a variable for the return var. */
5227 if (DECL_RESULT (decl) != NULL
5228 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5231 const char *newname;
5233 tree resultdecl = decl;
5235 if (DECL_RESULT (decl))
5236 resultdecl = DECL_RESULT (decl);
5238 asprintf (&tempname, "%s.result", name);
5239 newname = ggc_strdup (tempname);
5242 resultvi = new_var_info (resultdecl, newname);
5243 resultvi->offset = fi_result;
5245 resultvi->fullsize = vi->fullsize;
5246 resultvi->is_full_var = true;
5247 if (DECL_RESULT (decl))
5248 resultvi->may_have_pointers = could_have_pointers (DECL_RESULT (decl));
5249 gcc_assert (prev_vi->offset < resultvi->offset);
5250 prev_vi->next = resultvi;
5252 if (DECL_RESULT (decl))
5253 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5256 /* Set up variables for each argument. */
5257 arg = DECL_ARGUMENTS (decl);
5258 for (i = 0; i < num_args; i++)
5261 const char *newname;
5263 tree argdecl = decl;
5268 asprintf (&tempname, "%s.arg%d", name, i);
5269 newname = ggc_strdup (tempname);
5272 argvi = new_var_info (argdecl, newname);
5273 argvi->offset = fi_parm_base + i;
5275 argvi->is_full_var = true;
5276 argvi->fullsize = vi->fullsize;
5278 argvi->may_have_pointers = could_have_pointers (arg);
5279 gcc_assert (prev_vi->offset < argvi->offset);
5280 prev_vi->next = argvi;
5284 insert_vi_for_tree (arg, argvi);
5285 arg = DECL_CHAIN (arg);
5289 /* Add one representative for all further args. */
5293 const char *newname;
5297 asprintf (&tempname, "%s.varargs", name);
5298 newname = ggc_strdup (tempname);
5301 /* We need sth that can be pointed to for va_start. */
5302 decl = create_tmp_var_raw (ptr_type_node, name);
5305 argvi = new_var_info (decl, newname);
5306 argvi->offset = fi_parm_base + num_args;
5308 argvi->is_full_var = true;
5309 argvi->is_heap_var = true;
5310 argvi->fullsize = vi->fullsize;
5311 gcc_assert (prev_vi->offset < argvi->offset);
5312 prev_vi->next = argvi;
5320 /* Return true if FIELDSTACK contains fields that overlap.
5321 FIELDSTACK is assumed to be sorted by offset. */
5324 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5326 fieldoff_s *fo = NULL;
5328 HOST_WIDE_INT lastoffset = -1;
5330 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5332 if (fo->offset == lastoffset)
5334 lastoffset = fo->offset;
5339 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5340 This will also create any varinfo structures necessary for fields
5344 create_variable_info_for_1 (tree decl, const char *name)
5346 varinfo_t vi, newvi;
5347 tree decl_type = TREE_TYPE (decl);
5348 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5349 VEC (fieldoff_s,heap) *fieldstack = NULL;
5354 || !host_integerp (declsize, 1))
5356 vi = new_var_info (decl, name);
5360 vi->is_unknown_size_var = true;
5361 vi->is_full_var = true;
5362 vi->may_have_pointers = could_have_pointers (decl);
5366 /* Collect field information. */
5367 if (use_field_sensitive
5368 && var_can_have_subvars (decl)
5369 /* ??? Force us to not use subfields for global initializers
5370 in IPA mode. Else we'd have to parse arbitrary initializers. */
5372 && is_global_var (decl)
5373 && DECL_INITIAL (decl)))
5375 fieldoff_s *fo = NULL;
5376 bool notokay = false;
5379 push_fields_onto_fieldstack (decl_type, &fieldstack, 0,
5381 || DECL_EXTERNAL (decl)
5382 || TREE_ADDRESSABLE (decl));
5384 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5385 if (fo->has_unknown_size
5392 /* We can't sort them if we have a field with a variable sized type,
5393 which will make notokay = true. In that case, we are going to return
5394 without creating varinfos for the fields anyway, so sorting them is a
5398 sort_fieldstack (fieldstack);
5399 /* Due to some C++ FE issues, like PR 22488, we might end up
5400 what appear to be overlapping fields even though they,
5401 in reality, do not overlap. Until the C++ FE is fixed,
5402 we will simply disable field-sensitivity for these cases. */
5403 notokay = check_for_overlaps (fieldstack);
5407 VEC_free (fieldoff_s, heap, fieldstack);
5410 /* If we didn't end up collecting sub-variables create a full
5411 variable for the decl. */
5412 if (VEC_length (fieldoff_s, fieldstack) <= 1
5413 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5415 vi = new_var_info (decl, name);
5417 vi->may_have_pointers = could_have_pointers (decl);
5418 vi->fullsize = TREE_INT_CST_LOW (declsize);
5419 vi->size = vi->fullsize;
5420 vi->is_full_var = true;
5421 VEC_free (fieldoff_s, heap, fieldstack);
5425 vi = new_var_info (decl, name);
5426 vi->fullsize = TREE_INT_CST_LOW (declsize);
5427 for (i = 0, newvi = vi;
5428 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5429 ++i, newvi = newvi->next)
5431 const char *newname = "NULL";
5436 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5437 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5438 newname = ggc_strdup (tempname);
5441 newvi->name = newname;
5442 newvi->offset = fo->offset;
5443 newvi->size = fo->size;
5444 newvi->fullsize = vi->fullsize;
5445 newvi->may_have_pointers = fo->may_have_pointers;
5446 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5447 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5448 newvi->next = new_var_info (decl, name);
5451 VEC_free (fieldoff_s, heap, fieldstack);
5457 create_variable_info_for (tree decl, const char *name)
5459 varinfo_t vi = create_variable_info_for_1 (decl, name);
5460 unsigned int id = vi->id;
5462 insert_vi_for_tree (decl, vi);
5464 /* Create initial constraints for globals. */
5465 for (; vi; vi = vi->next)
5467 if (!vi->may_have_pointers
5468 || !vi->is_global_var)
5471 /* Mark global restrict qualified pointers. */
5472 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5473 && TYPE_RESTRICT (TREE_TYPE (decl)))
5474 || vi->only_restrict_pointers)
5475 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5477 /* For escaped variables initialize them from nonlocal. */
5479 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5480 make_copy_constraint (vi, nonlocal_id);
5482 /* If this is a global variable with an initializer and we are in
5483 IPA mode generate constraints for it. In non-IPA mode
5484 the initializer from nonlocal is all we need. */
5486 && DECL_INITIAL (decl))
5488 VEC (ce_s, heap) *rhsc = NULL;
5489 struct constraint_expr lhs, *rhsp;
5491 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5495 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5496 process_constraint (new_constraint (lhs, *rhsp));
5497 /* If this is a variable that escapes from the unit
5498 the initializer escapes as well. */
5499 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5501 lhs.var = escaped_id;
5504 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5505 process_constraint (new_constraint (lhs, *rhsp));
5507 VEC_free (ce_s, heap, rhsc);
5514 /* Print out the points-to solution for VAR to FILE. */
5517 dump_solution_for_var (FILE *file, unsigned int var)
5519 varinfo_t vi = get_varinfo (var);
5523 /* Dump the solution for unified vars anyway, this avoids difficulties
5524 in scanning dumps in the testsuite. */
5525 fprintf (file, "%s = { ", vi->name);
5526 vi = get_varinfo (find (var));
5527 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5528 fprintf (file, "%s ", get_varinfo (i)->name);
5529 fprintf (file, "}");
5531 /* But note when the variable was unified. */
5533 fprintf (file, " same as %s", vi->name);
5535 fprintf (file, "\n");
5538 /* Print the points-to solution for VAR to stdout. */
5541 debug_solution_for_var (unsigned int var)
5543 dump_solution_for_var (stdout, var);
5546 /* Create varinfo structures for all of the variables in the
5547 function for intraprocedural mode. */
5550 intra_create_variable_infos (void)
5554 /* For each incoming pointer argument arg, create the constraint ARG
5555 = NONLOCAL or a dummy variable if it is a restrict qualified
5556 passed-by-reference argument. */
5557 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5561 if (!could_have_pointers (t))
5564 /* For restrict qualified pointers to objects passed by
5565 reference build a real representative for the pointed-to object. */
5566 if (DECL_BY_REFERENCE (t)
5567 && POINTER_TYPE_P (TREE_TYPE (t))
5568 && TYPE_RESTRICT (TREE_TYPE (t)))
5570 struct constraint_expr lhsc, rhsc;
5572 tree heapvar = heapvar_lookup (t, 0);
5573 if (heapvar == NULL_TREE)
5576 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5578 DECL_EXTERNAL (heapvar) = 1;
5579 heapvar_insert (t, 0, heapvar);
5580 ann = get_var_ann (heapvar);
5581 ann->is_heapvar = 1;
5583 if (gimple_referenced_vars (cfun))
5584 add_referenced_var (heapvar);
5585 lhsc.var = get_vi_for_tree (t)->id;
5588 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5589 rhsc.type = ADDRESSOF;
5591 process_constraint (new_constraint (lhsc, rhsc));
5592 vi->is_restrict_var = 1;
5596 for (p = get_vi_for_tree (t); p; p = p->next)
5598 if (p->may_have_pointers)
5599 make_constraint_from (p, nonlocal_id);
5600 if (p->only_restrict_pointers)
5601 make_constraint_from_restrict (p, "PARM_RESTRICT");
5603 if (POINTER_TYPE_P (TREE_TYPE (t))
5604 && TYPE_RESTRICT (TREE_TYPE (t)))
5605 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5608 /* Add a constraint for a result decl that is passed by reference. */
5609 if (DECL_RESULT (cfun->decl)
5610 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5612 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5614 for (p = result_vi; p; p = p->next)
5615 make_constraint_from (p, nonlocal_id);
5618 /* Add a constraint for the incoming static chain parameter. */
5619 if (cfun->static_chain_decl != NULL_TREE)
5621 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5623 for (p = chain_vi; p; p = p->next)
5624 make_constraint_from (p, nonlocal_id);
5628 /* Structure used to put solution bitmaps in a hashtable so they can
5629 be shared among variables with the same points-to set. */
5631 typedef struct shared_bitmap_info
5635 } *shared_bitmap_info_t;
5636 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5638 static htab_t shared_bitmap_table;
5640 /* Hash function for a shared_bitmap_info_t */
5643 shared_bitmap_hash (const void *p)
5645 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5646 return bi->hashcode;
5649 /* Equality function for two shared_bitmap_info_t's. */
5652 shared_bitmap_eq (const void *p1, const void *p2)
5654 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5655 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5656 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5659 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5660 existing instance if there is one, NULL otherwise. */
5663 shared_bitmap_lookup (bitmap pt_vars)
5666 struct shared_bitmap_info sbi;
5668 sbi.pt_vars = pt_vars;
5669 sbi.hashcode = bitmap_hash (pt_vars);
5671 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5672 sbi.hashcode, NO_INSERT);
5676 return ((shared_bitmap_info_t) *slot)->pt_vars;
5680 /* Add a bitmap to the shared bitmap hashtable. */
5683 shared_bitmap_add (bitmap pt_vars)
5686 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5688 sbi->pt_vars = pt_vars;
5689 sbi->hashcode = bitmap_hash (pt_vars);
5691 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5692 sbi->hashcode, INSERT);
5693 gcc_assert (!*slot);
5694 *slot = (void *) sbi;
5698 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5701 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5706 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5708 varinfo_t vi = get_varinfo (i);
5710 /* The only artificial variables that are allowed in a may-alias
5711 set are heap variables. */
5712 if (vi->is_artificial_var && !vi->is_heap_var)
5715 if (TREE_CODE (vi->decl) == VAR_DECL
5716 || TREE_CODE (vi->decl) == PARM_DECL
5717 || TREE_CODE (vi->decl) == RESULT_DECL)
5719 /* If we are in IPA mode we will not recompute points-to
5720 sets after inlining so make sure they stay valid. */
5722 && !DECL_PT_UID_SET_P (vi->decl))
5723 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5725 /* Add the decl to the points-to set. Note that the points-to
5726 set contains global variables. */
5727 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5728 if (vi->is_global_var)
5729 pt->vars_contains_global = true;
5735 /* Compute the points-to solution *PT for the variable VI. */
5738 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5742 bitmap finished_solution;
5746 memset (pt, 0, sizeof (struct pt_solution));
5748 /* This variable may have been collapsed, let's get the real
5750 vi = get_varinfo (find (orig_vi->id));
5752 /* Translate artificial variables into SSA_NAME_PTR_INFO
5754 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5756 varinfo_t vi = get_varinfo (i);
5758 if (vi->is_artificial_var)
5760 if (vi->id == nothing_id)
5762 else if (vi->id == escaped_id)
5765 pt->ipa_escaped = 1;
5769 else if (vi->id == nonlocal_id)
5771 else if (vi->is_heap_var)
5772 /* We represent heapvars in the points-to set properly. */
5774 else if (vi->id == readonly_id)
5777 else if (vi->id == anything_id
5778 || vi->id == integer_id)
5781 if (vi->is_restrict_var)
5782 pt->vars_contains_restrict = true;
5785 /* Instead of doing extra work, simply do not create
5786 elaborate points-to information for pt_anything pointers. */
5788 && (orig_vi->is_artificial_var
5789 || !pt->vars_contains_restrict))
5792 /* Share the final set of variables when possible. */
5793 finished_solution = BITMAP_GGC_ALLOC ();
5794 stats.points_to_sets_created++;
5796 set_uids_in_ptset (finished_solution, vi->solution, pt);
5797 result = shared_bitmap_lookup (finished_solution);
5800 shared_bitmap_add (finished_solution);
5801 pt->vars = finished_solution;
5806 bitmap_clear (finished_solution);
5810 /* Given a pointer variable P, fill in its points-to set. */
5813 find_what_p_points_to (tree p)
5815 struct ptr_info_def *pi;
5819 /* For parameters, get at the points-to set for the actual parm
5821 if (TREE_CODE (p) == SSA_NAME
5822 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5823 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5824 && SSA_NAME_IS_DEFAULT_DEF (p))
5825 lookup_p = SSA_NAME_VAR (p);
5827 vi = lookup_vi_for_tree (lookup_p);
5831 pi = get_ptr_info (p);
5832 find_what_var_points_to (vi, &pi->pt);
5836 /* Query statistics for points-to solutions. */
5839 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5840 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5841 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5842 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5846 dump_pta_stats (FILE *s)
5848 fprintf (s, "\nPTA query stats:\n");
5849 fprintf (s, " pt_solution_includes: "
5850 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5851 HOST_WIDE_INT_PRINT_DEC" queries\n",
5852 pta_stats.pt_solution_includes_no_alias,
5853 pta_stats.pt_solution_includes_no_alias
5854 + pta_stats.pt_solution_includes_may_alias);
5855 fprintf (s, " pt_solutions_intersect: "
5856 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5857 HOST_WIDE_INT_PRINT_DEC" queries\n",
5858 pta_stats.pt_solutions_intersect_no_alias,
5859 pta_stats.pt_solutions_intersect_no_alias
5860 + pta_stats.pt_solutions_intersect_may_alias);
5864 /* Reset the points-to solution *PT to a conservative default
5865 (point to anything). */
5868 pt_solution_reset (struct pt_solution *pt)
5870 memset (pt, 0, sizeof (struct pt_solution));
5871 pt->anything = true;
5874 /* Set the points-to solution *PT to point only to the variables
5875 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5876 global variables and VARS_CONTAINS_RESTRICT specifies whether
5877 it contains restrict tag variables. */
5880 pt_solution_set (struct pt_solution *pt, bitmap vars,
5881 bool vars_contains_global, bool vars_contains_restrict)
5883 memset (pt, 0, sizeof (struct pt_solution));
5885 pt->vars_contains_global = vars_contains_global;
5886 pt->vars_contains_restrict = vars_contains_restrict;
5889 /* Set the points-to solution *PT to point only to the variable VAR. */
5892 pt_solution_set_var (struct pt_solution *pt, tree var)
5894 memset (pt, 0, sizeof (struct pt_solution));
5895 pt->vars = BITMAP_GGC_ALLOC ();
5896 bitmap_set_bit (pt->vars, DECL_UID (var));
5897 pt->vars_contains_global = is_global_var (var);
5900 /* Computes the union of the points-to solutions *DEST and *SRC and
5901 stores the result in *DEST. This changes the points-to bitmap
5902 of *DEST and thus may not be used if that might be shared.
5903 The points-to bitmap of *SRC and *DEST will not be shared after
5904 this function if they were not before. */
5907 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5909 dest->anything |= src->anything;
5912 pt_solution_reset (dest);
5916 dest->nonlocal |= src->nonlocal;
5917 dest->escaped |= src->escaped;
5918 dest->ipa_escaped |= src->ipa_escaped;
5919 dest->null |= src->null;
5920 dest->vars_contains_global |= src->vars_contains_global;
5921 dest->vars_contains_restrict |= src->vars_contains_restrict;
5926 dest->vars = BITMAP_GGC_ALLOC ();
5927 bitmap_ior_into (dest->vars, src->vars);
5930 /* Return true if the points-to solution *PT is empty. */
5933 pt_solution_empty_p (struct pt_solution *pt)
5940 && !bitmap_empty_p (pt->vars))
5943 /* If the solution includes ESCAPED, check if that is empty. */
5945 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5948 /* If the solution includes ESCAPED, check if that is empty. */
5950 && !pt_solution_empty_p (&ipa_escaped_pt))
5956 /* Return true if the points-to solution *PT includes global memory. */
5959 pt_solution_includes_global (struct pt_solution *pt)
5963 || pt->vars_contains_global)
5967 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5969 if (pt->ipa_escaped)
5970 return pt_solution_includes_global (&ipa_escaped_pt);
5972 /* ??? This predicate is not correct for the IPA-PTA solution
5973 as we do not properly distinguish between unit escape points
5974 and global variables. */
5975 if (cfun->gimple_df->ipa_pta)
5981 /* Return true if the points-to solution *PT includes the variable
5982 declaration DECL. */
5985 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5991 && is_global_var (decl))
5995 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5998 /* If the solution includes ESCAPED, check it. */
6000 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
6003 /* If the solution includes ESCAPED, check it. */
6005 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6012 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6014 bool res = pt_solution_includes_1 (pt, decl);
6016 ++pta_stats.pt_solution_includes_may_alias;
6018 ++pta_stats.pt_solution_includes_no_alias;
6022 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6026 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6028 if (pt1->anything || pt2->anything)
6031 /* If either points to unknown global memory and the other points to
6032 any global memory they alias. */
6035 || pt2->vars_contains_global))
6037 && pt1->vars_contains_global))
6040 /* Check the escaped solution if required. */
6041 if ((pt1->escaped || pt2->escaped)
6042 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6044 /* If both point to escaped memory and that solution
6045 is not empty they alias. */
6046 if (pt1->escaped && pt2->escaped)
6049 /* If either points to escaped memory see if the escaped solution
6050 intersects with the other. */
6052 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6054 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6058 /* Check the escaped solution if required.
6059 ??? Do we need to check the local against the IPA escaped sets? */
6060 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6061 && !pt_solution_empty_p (&ipa_escaped_pt))
6063 /* If both point to escaped memory and that solution
6064 is not empty they alias. */
6065 if (pt1->ipa_escaped && pt2->ipa_escaped)
6068 /* If either points to escaped memory see if the escaped solution
6069 intersects with the other. */
6070 if ((pt1->ipa_escaped
6071 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6072 || (pt2->ipa_escaped
6073 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6077 /* Now both pointers alias if their points-to solution intersects. */
6080 && bitmap_intersect_p (pt1->vars, pt2->vars));
6084 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6086 bool res = pt_solutions_intersect_1 (pt1, pt2);
6088 ++pta_stats.pt_solutions_intersect_may_alias;
6090 ++pta_stats.pt_solutions_intersect_no_alias;
6094 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6095 qualified pointers are possibly based on the same pointer. */
6098 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6099 struct pt_solution *pt2)
6101 /* If we deal with points-to solutions of two restrict qualified
6102 pointers solely rely on the pointed-to variable bitmap intersection.
6103 For two pointers that are based on each other the bitmaps will
6105 if (pt1->vars_contains_restrict
6106 && pt2->vars_contains_restrict)
6108 gcc_assert (pt1->vars && pt2->vars);
6109 return bitmap_intersect_p (pt1->vars, pt2->vars);
6116 /* Dump points-to information to OUTFILE. */
6119 dump_sa_points_to_info (FILE *outfile)
6123 fprintf (outfile, "\nPoints-to sets\n\n");
6125 if (dump_flags & TDF_STATS)
6127 fprintf (outfile, "Stats:\n");
6128 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6129 fprintf (outfile, "Non-pointer vars: %d\n",
6130 stats.nonpointer_vars);
6131 fprintf (outfile, "Statically unified vars: %d\n",
6132 stats.unified_vars_static);
6133 fprintf (outfile, "Dynamically unified vars: %d\n",
6134 stats.unified_vars_dynamic);
6135 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6136 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6137 fprintf (outfile, "Number of implicit edges: %d\n",
6138 stats.num_implicit_edges);
6141 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6143 varinfo_t vi = get_varinfo (i);
6144 if (!vi->may_have_pointers)
6146 dump_solution_for_var (outfile, i);
6151 /* Debug points-to information to stderr. */
6154 debug_sa_points_to_info (void)
6156 dump_sa_points_to_info (stderr);
6160 /* Initialize the always-existing constraint variables for NULL
6161 ANYTHING, READONLY, and INTEGER */
6164 init_base_vars (void)
6166 struct constraint_expr lhs, rhs;
6167 varinfo_t var_anything;
6168 varinfo_t var_nothing;
6169 varinfo_t var_readonly;
6170 varinfo_t var_escaped;
6171 varinfo_t var_nonlocal;
6172 varinfo_t var_storedanything;
6173 varinfo_t var_integer;
6175 /* Create the NULL variable, used to represent that a variable points
6177 var_nothing = new_var_info (NULL_TREE, "NULL");
6178 gcc_assert (var_nothing->id == nothing_id);
6179 var_nothing->is_artificial_var = 1;
6180 var_nothing->offset = 0;
6181 var_nothing->size = ~0;
6182 var_nothing->fullsize = ~0;
6183 var_nothing->is_special_var = 1;
6184 var_nothing->may_have_pointers = 0;
6185 var_nothing->is_global_var = 0;
6187 /* Create the ANYTHING variable, used to represent that a variable
6188 points to some unknown piece of memory. */
6189 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6190 gcc_assert (var_anything->id == anything_id);
6191 var_anything->is_artificial_var = 1;
6192 var_anything->size = ~0;
6193 var_anything->offset = 0;
6194 var_anything->next = NULL;
6195 var_anything->fullsize = ~0;
6196 var_anything->is_special_var = 1;
6198 /* Anything points to anything. This makes deref constraints just
6199 work in the presence of linked list and other p = *p type loops,
6200 by saying that *ANYTHING = ANYTHING. */
6202 lhs.var = anything_id;
6204 rhs.type = ADDRESSOF;
6205 rhs.var = anything_id;
6208 /* This specifically does not use process_constraint because
6209 process_constraint ignores all anything = anything constraints, since all
6210 but this one are redundant. */
6211 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6213 /* Create the READONLY variable, used to represent that a variable
6214 points to readonly memory. */
6215 var_readonly = new_var_info (NULL_TREE, "READONLY");
6216 gcc_assert (var_readonly->id == readonly_id);
6217 var_readonly->is_artificial_var = 1;
6218 var_readonly->offset = 0;
6219 var_readonly->size = ~0;
6220 var_readonly->fullsize = ~0;
6221 var_readonly->next = NULL;
6222 var_readonly->is_special_var = 1;
6224 /* readonly memory points to anything, in order to make deref
6225 easier. In reality, it points to anything the particular
6226 readonly variable can point to, but we don't track this
6229 lhs.var = readonly_id;
6231 rhs.type = ADDRESSOF;
6232 rhs.var = readonly_id; /* FIXME */
6234 process_constraint (new_constraint (lhs, rhs));
6236 /* Create the ESCAPED variable, used to represent the set of escaped
6238 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6239 gcc_assert (var_escaped->id == escaped_id);
6240 var_escaped->is_artificial_var = 1;
6241 var_escaped->offset = 0;
6242 var_escaped->size = ~0;
6243 var_escaped->fullsize = ~0;
6244 var_escaped->is_special_var = 0;
6246 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6248 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6249 gcc_assert (var_nonlocal->id == nonlocal_id);
6250 var_nonlocal->is_artificial_var = 1;
6251 var_nonlocal->offset = 0;
6252 var_nonlocal->size = ~0;
6253 var_nonlocal->fullsize = ~0;
6254 var_nonlocal->is_special_var = 1;
6256 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6258 lhs.var = escaped_id;
6261 rhs.var = escaped_id;
6263 process_constraint (new_constraint (lhs, rhs));
6265 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6266 whole variable escapes. */
6268 lhs.var = escaped_id;
6271 rhs.var = escaped_id;
6272 rhs.offset = UNKNOWN_OFFSET;
6273 process_constraint (new_constraint (lhs, rhs));
6275 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6276 everything pointed to by escaped points to what global memory can
6279 lhs.var = escaped_id;
6282 rhs.var = nonlocal_id;
6284 process_constraint (new_constraint (lhs, rhs));
6286 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6287 global memory may point to global memory and escaped memory. */
6289 lhs.var = nonlocal_id;
6291 rhs.type = ADDRESSOF;
6292 rhs.var = nonlocal_id;
6294 process_constraint (new_constraint (lhs, rhs));
6295 rhs.type = ADDRESSOF;
6296 rhs.var = escaped_id;
6298 process_constraint (new_constraint (lhs, rhs));
6300 /* Create the STOREDANYTHING variable, used to represent the set of
6301 variables stored to *ANYTHING. */
6302 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6303 gcc_assert (var_storedanything->id == storedanything_id);
6304 var_storedanything->is_artificial_var = 1;
6305 var_storedanything->offset = 0;
6306 var_storedanything->size = ~0;
6307 var_storedanything->fullsize = ~0;
6308 var_storedanything->is_special_var = 0;
6310 /* Create the INTEGER variable, used to represent that a variable points
6311 to what an INTEGER "points to". */
6312 var_integer = new_var_info (NULL_TREE, "INTEGER");
6313 gcc_assert (var_integer->id == integer_id);
6314 var_integer->is_artificial_var = 1;
6315 var_integer->size = ~0;
6316 var_integer->fullsize = ~0;
6317 var_integer->offset = 0;
6318 var_integer->next = NULL;
6319 var_integer->is_special_var = 1;
6321 /* INTEGER = ANYTHING, because we don't know where a dereference of
6322 a random integer will point to. */
6324 lhs.var = integer_id;
6326 rhs.type = ADDRESSOF;
6327 rhs.var = anything_id;
6329 process_constraint (new_constraint (lhs, rhs));
6332 /* Initialize things necessary to perform PTA */
6335 init_alias_vars (void)
6337 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6339 bitmap_obstack_initialize (&pta_obstack);
6340 bitmap_obstack_initialize (&oldpta_obstack);
6341 bitmap_obstack_initialize (&predbitmap_obstack);
6343 constraint_pool = create_alloc_pool ("Constraint pool",
6344 sizeof (struct constraint), 30);
6345 variable_info_pool = create_alloc_pool ("Variable info pool",
6346 sizeof (struct variable_info), 30);
6347 constraints = VEC_alloc (constraint_t, heap, 8);
6348 varmap = VEC_alloc (varinfo_t, heap, 8);
6349 vi_for_tree = pointer_map_create ();
6350 call_stmt_vars = pointer_map_create ();
6352 memset (&stats, 0, sizeof (stats));
6353 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6354 shared_bitmap_eq, free);
6358 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6359 predecessor edges. */
6362 remove_preds_and_fake_succs (constraint_graph_t graph)
6366 /* Clear the implicit ref and address nodes from the successor
6368 for (i = 0; i < FIRST_REF_NODE; i++)
6370 if (graph->succs[i])
6371 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6372 FIRST_REF_NODE * 2);
6375 /* Free the successor list for the non-ref nodes. */
6376 for (i = FIRST_REF_NODE; i < graph->size; i++)
6378 if (graph->succs[i])
6379 BITMAP_FREE (graph->succs[i]);
6382 /* Now reallocate the size of the successor list as, and blow away
6383 the predecessor bitmaps. */
6384 graph->size = VEC_length (varinfo_t, varmap);
6385 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6387 free (graph->implicit_preds);
6388 graph->implicit_preds = NULL;
6389 free (graph->preds);
6390 graph->preds = NULL;
6391 bitmap_obstack_release (&predbitmap_obstack);
6394 /* Initialize the heapvar for statement mapping. */
6397 init_alias_heapvars (void)
6399 if (!heapvar_for_stmt)
6400 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6404 /* Delete the heapvar for statement mapping. */
6407 delete_alias_heapvars (void)
6409 if (heapvar_for_stmt)
6410 htab_delete (heapvar_for_stmt);
6411 heapvar_for_stmt = NULL;
6414 /* Solve the constraint set. */
6417 solve_constraints (void)
6419 struct scc_info *si;
6423 "\nCollapsing static cycles and doing variable "
6426 init_graph (VEC_length (varinfo_t, varmap) * 2);
6429 fprintf (dump_file, "Building predecessor graph\n");
6430 build_pred_graph ();
6433 fprintf (dump_file, "Detecting pointer and location "
6435 si = perform_var_substitution (graph);
6438 fprintf (dump_file, "Rewriting constraints and unifying "
6440 rewrite_constraints (graph, si);
6442 build_succ_graph ();
6443 free_var_substitution_info (si);
6445 if (dump_file && (dump_flags & TDF_GRAPH))
6446 dump_constraint_graph (dump_file);
6448 move_complex_constraints (graph);
6451 fprintf (dump_file, "Uniting pointer but not location equivalent "
6453 unite_pointer_equivalences (graph);
6456 fprintf (dump_file, "Finding indirect cycles\n");
6457 find_indirect_cycles (graph);
6459 /* Implicit nodes and predecessors are no longer necessary at this
6461 remove_preds_and_fake_succs (graph);
6464 fprintf (dump_file, "Solving graph\n");
6466 solve_graph (graph);
6469 dump_sa_points_to_info (dump_file);
6472 /* Create points-to sets for the current function. See the comments
6473 at the start of the file for an algorithmic overview. */
6476 compute_points_to_sets (void)
6482 timevar_push (TV_TREE_PTA);
6485 init_alias_heapvars ();
6487 intra_create_variable_infos ();
6489 /* Now walk all statements and build the constraint set. */
6492 gimple_stmt_iterator gsi;
6494 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6496 gimple phi = gsi_stmt (gsi);
6498 if (is_gimple_reg (gimple_phi_result (phi)))
6499 find_func_aliases (phi);
6502 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6504 gimple stmt = gsi_stmt (gsi);
6506 find_func_aliases (stmt);
6512 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6513 dump_constraints (dump_file, 0);
6516 /* From the constraints compute the points-to sets. */
6517 solve_constraints ();
6519 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6520 find_what_var_points_to (get_varinfo (escaped_id),
6521 &cfun->gimple_df->escaped);
6523 /* Make sure the ESCAPED solution (which is used as placeholder in
6524 other solutions) does not reference itself. This simplifies
6525 points-to solution queries. */
6526 cfun->gimple_df->escaped.escaped = 0;
6528 /* Mark escaped HEAP variables as global. */
6529 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6531 && !vi->is_restrict_var
6532 && !vi->is_global_var)
6533 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6534 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6536 /* Compute the points-to sets for pointer SSA_NAMEs. */
6537 for (i = 0; i < num_ssa_names; ++i)
6539 tree ptr = ssa_name (i);
6541 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6542 find_what_p_points_to (ptr);
6545 /* Compute the call-used/clobbered sets. */
6548 gimple_stmt_iterator gsi;
6550 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6552 gimple stmt = gsi_stmt (gsi);
6553 struct pt_solution *pt;
6554 if (!is_gimple_call (stmt))
6557 pt = gimple_call_use_set (stmt);
6558 if (gimple_call_flags (stmt) & ECF_CONST)
6559 memset (pt, 0, sizeof (struct pt_solution));
6560 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6562 find_what_var_points_to (vi, pt);
6563 /* Escaped (and thus nonlocal) variables are always
6564 implicitly used by calls. */
6565 /* ??? ESCAPED can be empty even though NONLOCAL
6572 /* If there is nothing special about this call then
6573 we have made everything that is used also escape. */
6574 *pt = cfun->gimple_df->escaped;
6578 pt = gimple_call_clobber_set (stmt);
6579 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6580 memset (pt, 0, sizeof (struct pt_solution));
6581 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6583 find_what_var_points_to (vi, pt);
6584 /* Escaped (and thus nonlocal) variables are always
6585 implicitly clobbered by calls. */
6586 /* ??? ESCAPED can be empty even though NONLOCAL
6593 /* If there is nothing special about this call then
6594 we have made everything that is used also escape. */
6595 *pt = cfun->gimple_df->escaped;
6601 timevar_pop (TV_TREE_PTA);
6605 /* Delete created points-to sets. */
6608 delete_points_to_sets (void)
6612 htab_delete (shared_bitmap_table);
6613 if (dump_file && (dump_flags & TDF_STATS))
6614 fprintf (dump_file, "Points to sets created:%d\n",
6615 stats.points_to_sets_created);
6617 pointer_map_destroy (vi_for_tree);
6618 pointer_map_destroy (call_stmt_vars);
6619 bitmap_obstack_release (&pta_obstack);
6620 VEC_free (constraint_t, heap, constraints);
6622 for (i = 0; i < graph->size; i++)
6623 VEC_free (constraint_t, heap, graph->complex[i]);
6624 free (graph->complex);
6627 free (graph->succs);
6629 free (graph->pe_rep);
6630 free (graph->indirect_cycles);
6633 VEC_free (varinfo_t, heap, varmap);
6634 free_alloc_pool (variable_info_pool);
6635 free_alloc_pool (constraint_pool);
6639 /* Compute points-to information for every SSA_NAME pointer in the
6640 current function and compute the transitive closure of escaped
6641 variables to re-initialize the call-clobber states of local variables. */
6644 compute_may_aliases (void)
6646 if (cfun->gimple_df->ipa_pta)
6650 fprintf (dump_file, "\nNot re-computing points-to information "
6651 "because IPA points-to information is available.\n\n");
6653 /* But still dump what we have remaining it. */
6654 dump_alias_info (dump_file);
6656 if (dump_flags & TDF_DETAILS)
6657 dump_referenced_vars (dump_file);
6663 /* For each pointer P_i, determine the sets of variables that P_i may
6664 point-to. Compute the reachability set of escaped and call-used
6666 compute_points_to_sets ();
6668 /* Debugging dumps. */
6671 dump_alias_info (dump_file);
6673 if (dump_flags & TDF_DETAILS)
6674 dump_referenced_vars (dump_file);
6677 /* Deallocate memory used by aliasing data structures and the internal
6678 points-to solution. */
6679 delete_points_to_sets ();
6681 gcc_assert (!need_ssa_update_p (cfun));
6687 gate_tree_pta (void)
6689 return flag_tree_pta;
6692 /* A dummy pass to cause points-to information to be computed via
6693 TODO_rebuild_alias. */
6695 struct gimple_opt_pass pass_build_alias =
6700 gate_tree_pta, /* gate */
6704 0, /* static_pass_number */
6705 TV_NONE, /* tv_id */
6706 PROP_cfg | PROP_ssa, /* properties_required */
6707 0, /* properties_provided */
6708 0, /* properties_destroyed */
6709 0, /* todo_flags_start */
6710 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6714 /* A dummy pass to cause points-to information to be computed via
6715 TODO_rebuild_alias. */
6717 struct gimple_opt_pass pass_build_ealias =
6721 "ealias", /* name */
6722 gate_tree_pta, /* gate */
6726 0, /* static_pass_number */
6727 TV_NONE, /* tv_id */
6728 PROP_cfg | PROP_ssa, /* properties_required */
6729 0, /* properties_provided */
6730 0, /* properties_destroyed */
6731 0, /* todo_flags_start */
6732 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6737 /* Return true if we should execute IPA PTA. */
6743 /* Don't bother doing anything if the program has errors. */
6747 /* IPA PTA solutions for ESCAPED. */
6748 struct pt_solution ipa_escaped_pt
6749 = { true, false, false, false, false, false, false, NULL };
6751 /* Execute the driver for IPA PTA. */
6753 ipa_pta_execute (void)
6755 struct cgraph_node *node;
6756 struct varpool_node *var;
6761 init_alias_heapvars ();
6764 /* Build the constraints. */
6765 for (node = cgraph_nodes; node; node = node->next)
6767 struct cgraph_node *alias;
6770 /* Nodes without a body are not interesting. Especially do not
6771 visit clones at this point for now - we get duplicate decls
6772 there for inline clones at least. */
6773 if (!gimple_has_body_p (node->decl)
6777 vi = create_function_info_for (node->decl,
6778 alias_get_name (node->decl));
6780 /* Associate the varinfo node with all aliases. */
6781 for (alias = node->same_body; alias; alias = alias->next)
6782 insert_vi_for_tree (alias->decl, vi);
6785 /* Create constraints for global variables and their initializers. */
6786 for (var = varpool_nodes; var; var = var->next)
6788 struct varpool_node *alias;
6791 vi = get_vi_for_tree (var->decl);
6793 /* Associate the varinfo node with all aliases. */
6794 for (alias = var->extra_name; alias; alias = alias->next)
6795 insert_vi_for_tree (alias->decl, vi);
6801 "Generating constraints for global initializers\n\n");
6802 dump_constraints (dump_file, 0);
6803 fprintf (dump_file, "\n");
6805 from = VEC_length (constraint_t, constraints);
6807 for (node = cgraph_nodes; node; node = node->next)
6809 struct function *func;
6813 /* Nodes without a body are not interesting. */
6814 if (!gimple_has_body_p (node->decl)
6821 "Generating constraints for %s", cgraph_node_name (node));
6822 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6823 fprintf (dump_file, " (%s)",
6824 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6825 fprintf (dump_file, "\n");
6828 func = DECL_STRUCT_FUNCTION (node->decl);
6829 old_func_decl = current_function_decl;
6831 current_function_decl = node->decl;
6833 /* For externally visible functions use local constraints for
6834 their arguments. For local functions we see all callers
6835 and thus do not need initial constraints for parameters. */
6836 if (node->local.externally_visible)
6837 intra_create_variable_infos ();
6839 /* Build constriants for the function body. */
6840 FOR_EACH_BB_FN (bb, func)
6842 gimple_stmt_iterator gsi;
6844 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6847 gimple phi = gsi_stmt (gsi);
6849 if (is_gimple_reg (gimple_phi_result (phi)))
6850 find_func_aliases (phi);
6853 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6855 gimple stmt = gsi_stmt (gsi);
6857 find_func_aliases (stmt);
6858 find_func_clobbers (stmt);
6862 current_function_decl = old_func_decl;
6867 fprintf (dump_file, "\n");
6868 dump_constraints (dump_file, from);
6869 fprintf (dump_file, "\n");
6871 from = VEC_length (constraint_t, constraints);
6874 /* From the constraints compute the points-to sets. */
6875 solve_constraints ();
6877 /* Compute the global points-to sets for ESCAPED.
6878 ??? Note that the computed escape set is not correct
6879 for the whole unit as we fail to consider graph edges to
6880 externally visible functions. */
6881 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6883 /* Make sure the ESCAPED solution (which is used as placeholder in
6884 other solutions) does not reference itself. This simplifies
6885 points-to solution queries. */
6886 ipa_escaped_pt.ipa_escaped = 0;
6888 /* Assign the points-to sets to the SSA names in the unit. */
6889 for (node = cgraph_nodes; node; node = node->next)
6892 struct function *fn;
6896 struct pt_solution uses, clobbers;
6897 struct cgraph_edge *e;
6899 /* Nodes without a body are not interesting. */
6900 if (!gimple_has_body_p (node->decl)
6904 fn = DECL_STRUCT_FUNCTION (node->decl);
6906 /* Compute the points-to sets for pointer SSA_NAMEs. */
6907 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6910 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6911 find_what_p_points_to (ptr);
6914 /* Compute the call-use and call-clobber sets for all direct calls. */
6915 fi = lookup_vi_for_tree (node->decl);
6916 gcc_assert (fi->is_fn_info);
6917 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6919 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6920 for (e = node->callers; e; e = e->next_caller)
6925 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6926 *gimple_call_use_set (e->call_stmt) = uses;
6929 /* Compute the call-use and call-clobber sets for indirect calls
6930 and calls to external functions. */
6931 FOR_EACH_BB_FN (bb, fn)
6933 gimple_stmt_iterator gsi;
6935 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6937 gimple stmt = gsi_stmt (gsi);
6938 struct pt_solution *pt;
6942 if (!is_gimple_call (stmt))
6945 /* Handle direct calls to external functions. */
6946 decl = gimple_call_fndecl (stmt);
6948 && (!(fi = lookup_vi_for_tree (decl))
6949 || !fi->is_fn_info))
6951 pt = gimple_call_use_set (stmt);
6952 if (gimple_call_flags (stmt) & ECF_CONST)
6953 memset (pt, 0, sizeof (struct pt_solution));
6954 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6956 find_what_var_points_to (vi, pt);
6957 /* Escaped (and thus nonlocal) variables are always
6958 implicitly used by calls. */
6959 /* ??? ESCAPED can be empty even though NONLOCAL
6962 pt->ipa_escaped = 1;
6966 /* If there is nothing special about this call then
6967 we have made everything that is used also escape. */
6968 *pt = ipa_escaped_pt;
6972 pt = gimple_call_clobber_set (stmt);
6973 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6974 memset (pt, 0, sizeof (struct pt_solution));
6975 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6977 find_what_var_points_to (vi, pt);
6978 /* Escaped (and thus nonlocal) variables are always
6979 implicitly clobbered by calls. */
6980 /* ??? ESCAPED can be empty even though NONLOCAL
6983 pt->ipa_escaped = 1;
6987 /* If there is nothing special about this call then
6988 we have made everything that is used also escape. */
6989 *pt = ipa_escaped_pt;
6994 /* Handle indirect calls. */
6996 && (fi = get_fi_for_callee (stmt)))
6998 /* We need to accumulate all clobbers/uses of all possible
7000 fi = get_varinfo (find (fi->id));
7001 /* If we cannot constrain the set of functions we'll end up
7002 calling we end up using/clobbering everything. */
7003 if (bitmap_bit_p (fi->solution, anything_id)
7004 || bitmap_bit_p (fi->solution, nonlocal_id)
7005 || bitmap_bit_p (fi->solution, escaped_id))
7007 pt_solution_reset (gimple_call_clobber_set (stmt));
7008 pt_solution_reset (gimple_call_use_set (stmt));
7014 struct pt_solution *uses, *clobbers;
7016 uses = gimple_call_use_set (stmt);
7017 clobbers = gimple_call_clobber_set (stmt);
7018 memset (uses, 0, sizeof (struct pt_solution));
7019 memset (clobbers, 0, sizeof (struct pt_solution));
7020 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7022 struct pt_solution sol;
7024 vi = get_varinfo (i);
7025 if (!vi->is_fn_info)
7027 /* ??? We could be more precise here? */
7029 uses->ipa_escaped = 1;
7030 clobbers->nonlocal = 1;
7031 clobbers->ipa_escaped = 1;
7035 if (!uses->anything)
7037 find_what_var_points_to
7038 (first_vi_for_offset (vi, fi_uses), &sol);
7039 pt_solution_ior_into (uses, &sol);
7041 if (!clobbers->anything)
7043 find_what_var_points_to
7044 (first_vi_for_offset (vi, fi_clobbers), &sol);
7045 pt_solution_ior_into (clobbers, &sol);
7053 fn->gimple_df->ipa_pta = true;
7056 delete_points_to_sets ();
7063 struct simple_ipa_opt_pass pass_ipa_pta =
7068 gate_ipa_pta, /* gate */
7069 ipa_pta_execute, /* execute */
7072 0, /* static_pass_number */
7073 TV_IPA_PTA, /* tv_id */
7074 0, /* properties_required */
7075 0, /* properties_provided */
7076 0, /* properties_destroyed */
7077 0, /* todo_flags_start */
7078 TODO_update_ssa /* todo_flags_finish */
7083 #include "gt-tree-ssa-structalias.h"