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);
2935 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2938 static HOST_WIDE_INT
2939 bitpos_of_field (const tree fdecl)
2942 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2943 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2946 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * 8
2947 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2951 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2952 resulting constraint expressions in *RESULTS. */
2955 get_constraint_for_ptr_offset (tree ptr, tree offset,
2956 VEC (ce_s, heap) **results)
2958 struct constraint_expr c;
2960 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2962 /* If we do not do field-sensitive PTA adding offsets to pointers
2963 does not change the points-to solution. */
2964 if (!use_field_sensitive)
2966 get_constraint_for_rhs (ptr, results);
2970 /* If the offset is not a non-negative integer constant that fits
2971 in a HOST_WIDE_INT, we have to fall back to a conservative
2972 solution which includes all sub-fields of all pointed-to
2973 variables of ptr. */
2974 if (offset == NULL_TREE
2975 || !host_integerp (offset, 0))
2976 rhsoffset = UNKNOWN_OFFSET;
2979 /* Make sure the bit-offset also fits. */
2980 rhsunitoffset = TREE_INT_CST_LOW (offset);
2981 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2982 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2983 rhsoffset = UNKNOWN_OFFSET;
2986 get_constraint_for_rhs (ptr, results);
2990 /* As we are eventually appending to the solution do not use
2991 VEC_iterate here. */
2992 n = VEC_length (ce_s, *results);
2993 for (j = 0; j < n; j++)
2996 c = *VEC_index (ce_s, *results, j);
2997 curr = get_varinfo (c.var);
2999 if (c.type == ADDRESSOF
3000 /* If this varinfo represents a full variable just use it. */
3001 && curr->is_full_var)
3003 else if (c.type == ADDRESSOF
3004 /* If we do not know the offset add all subfields. */
3005 && rhsoffset == UNKNOWN_OFFSET)
3007 varinfo_t temp = lookup_vi_for_tree (curr->decl);
3010 struct constraint_expr c2;
3012 c2.type = ADDRESSOF;
3014 if (c2.var != c.var)
3015 VEC_safe_push (ce_s, heap, *results, &c2);
3020 else if (c.type == ADDRESSOF)
3023 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
3025 /* Search the sub-field which overlaps with the
3026 pointed-to offset. If the result is outside of the variable
3027 we have to provide a conservative result, as the variable is
3028 still reachable from the resulting pointer (even though it
3029 technically cannot point to anything). The last and first
3030 sub-fields are such conservative results.
3031 ??? If we always had a sub-field for &object + 1 then
3032 we could represent this in a more precise way. */
3034 && curr->offset < offset)
3036 temp = first_or_preceding_vi_for_offset (curr, offset);
3038 /* If the found variable is not exactly at the pointed to
3039 result, we have to include the next variable in the
3040 solution as well. Otherwise two increments by offset / 2
3041 do not result in the same or a conservative superset
3043 if (temp->offset != offset
3044 && temp->next != NULL)
3046 struct constraint_expr c2;
3047 c2.var = temp->next->id;
3048 c2.type = ADDRESSOF;
3050 VEC_safe_push (ce_s, heap, *results, &c2);
3056 c.offset = rhsoffset;
3058 VEC_replace (ce_s, *results, j, &c);
3063 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
3064 If address_p is true the result will be taken its address of.
3065 If lhs_p is true then the constraint expression is assumed to be used
3069 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
3070 bool address_p, bool lhs_p)
3073 HOST_WIDE_INT bitsize = -1;
3074 HOST_WIDE_INT bitmaxsize = -1;
3075 HOST_WIDE_INT bitpos;
3077 struct constraint_expr *result;
3079 /* Some people like to do cute things like take the address of
3082 while (handled_component_p (forzero)
3083 || INDIRECT_REF_P (forzero)
3084 || TREE_CODE (forzero) == MEM_REF)
3085 forzero = TREE_OPERAND (forzero, 0);
3087 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3089 struct constraint_expr temp;
3092 temp.var = integer_id;
3094 VEC_safe_push (ce_s, heap, *results, &temp);
3098 /* Handle type-punning through unions. If we are extracting a pointer
3099 from a union via a possibly type-punning access that pointer
3100 points to anything, similar to a conversion of an integer to
3106 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3107 u = TREE_OPERAND (u, 0))
3108 if (TREE_CODE (u) == COMPONENT_REF
3109 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3111 struct constraint_expr temp;
3114 temp.var = anything_id;
3115 temp.type = ADDRESSOF;
3116 VEC_safe_push (ce_s, heap, *results, &temp);
3121 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3123 /* Pretend to take the address of the base, we'll take care of
3124 adding the required subset of sub-fields below. */
3125 get_constraint_for_1 (t, results, true, lhs_p);
3126 gcc_assert (VEC_length (ce_s, *results) == 1);
3127 result = VEC_last (ce_s, *results);
3129 if (result->type == SCALAR
3130 && get_varinfo (result->var)->is_full_var)
3131 /* For single-field vars do not bother about the offset. */
3133 else if (result->type == SCALAR)
3135 /* In languages like C, you can access one past the end of an
3136 array. You aren't allowed to dereference it, so we can
3137 ignore this constraint. When we handle pointer subtraction,
3138 we may have to do something cute here. */
3140 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3143 /* It's also not true that the constraint will actually start at the
3144 right offset, it may start in some padding. We only care about
3145 setting the constraint to the first actual field it touches, so
3147 struct constraint_expr cexpr = *result;
3149 VEC_pop (ce_s, *results);
3151 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3153 if (ranges_overlap_p (curr->offset, curr->size,
3154 bitpos, bitmaxsize))
3156 cexpr.var = curr->id;
3157 VEC_safe_push (ce_s, heap, *results, &cexpr);
3162 /* If we are going to take the address of this field then
3163 to be able to compute reachability correctly add at least
3164 the last field of the variable. */
3166 && VEC_length (ce_s, *results) == 0)
3168 curr = get_varinfo (cexpr.var);
3169 while (curr->next != NULL)
3171 cexpr.var = curr->id;
3172 VEC_safe_push (ce_s, heap, *results, &cexpr);
3174 else if (VEC_length (ce_s, *results) == 0)
3175 /* Assert that we found *some* field there. The user couldn't be
3176 accessing *only* padding. */
3177 /* Still the user could access one past the end of an array
3178 embedded in a struct resulting in accessing *only* padding. */
3179 /* Or accessing only padding via type-punning to a type
3180 that has a filed just in padding space. */
3182 cexpr.type = SCALAR;
3183 cexpr.var = anything_id;
3185 VEC_safe_push (ce_s, heap, *results, &cexpr);
3188 else if (bitmaxsize == 0)
3190 if (dump_file && (dump_flags & TDF_DETAILS))
3191 fprintf (dump_file, "Access to zero-sized part of variable,"
3195 if (dump_file && (dump_flags & TDF_DETAILS))
3196 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3198 else if (result->type == DEREF)
3200 /* If we do not know exactly where the access goes say so. Note
3201 that only for non-structure accesses we know that we access
3202 at most one subfiled of any variable. */
3204 || bitsize != bitmaxsize
3205 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3206 || result->offset == UNKNOWN_OFFSET)
3207 result->offset = UNKNOWN_OFFSET;
3209 result->offset += bitpos;
3211 else if (result->type == ADDRESSOF)
3213 /* We can end up here for component references on a
3214 VIEW_CONVERT_EXPR <>(&foobar). */
3215 result->type = SCALAR;
3216 result->var = anything_id;
3224 /* Dereference the constraint expression CONS, and return the result.
3225 DEREF (ADDRESSOF) = SCALAR
3226 DEREF (SCALAR) = DEREF
3227 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3228 This is needed so that we can handle dereferencing DEREF constraints. */
3231 do_deref (VEC (ce_s, heap) **constraints)
3233 struct constraint_expr *c;
3236 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3238 if (c->type == SCALAR)
3240 else if (c->type == ADDRESSOF)
3242 else if (c->type == DEREF)
3244 struct constraint_expr tmplhs;
3245 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3246 process_constraint (new_constraint (tmplhs, *c));
3247 c->var = tmplhs.var;
3254 /* Given a tree T, return the constraint expression for taking the
3258 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3260 struct constraint_expr *c;
3263 get_constraint_for_1 (t, results, true, true);
3265 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3267 if (c->type == DEREF)
3270 c->type = ADDRESSOF;
3274 /* Given a tree T, return the constraint expression for it. */
3277 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3280 struct constraint_expr temp;
3282 /* x = integer is all glommed to a single variable, which doesn't
3283 point to anything by itself. That is, of course, unless it is an
3284 integer constant being treated as a pointer, in which case, we
3285 will return that this is really the addressof anything. This
3286 happens below, since it will fall into the default case. The only
3287 case we know something about an integer treated like a pointer is
3288 when it is the NULL pointer, and then we just say it points to
3291 Do not do that if -fno-delete-null-pointer-checks though, because
3292 in that case *NULL does not fail, so it _should_ alias *anything.
3293 It is not worth adding a new option or renaming the existing one,
3294 since this case is relatively obscure. */
3295 if ((TREE_CODE (t) == INTEGER_CST
3296 && integer_zerop (t))
3297 /* The only valid CONSTRUCTORs in gimple with pointer typed
3298 elements are zero-initializer. But in IPA mode we also
3299 process global initializers, so verify at least. */
3300 || (TREE_CODE (t) == CONSTRUCTOR
3301 && CONSTRUCTOR_NELTS (t) == 0))
3303 if (flag_delete_null_pointer_checks)
3304 temp.var = nothing_id;
3306 temp.var = nonlocal_id;
3307 temp.type = ADDRESSOF;
3309 VEC_safe_push (ce_s, heap, *results, &temp);
3313 /* String constants are read-only. */
3314 if (TREE_CODE (t) == STRING_CST)
3316 temp.var = readonly_id;
3319 VEC_safe_push (ce_s, heap, *results, &temp);
3323 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3325 case tcc_expression:
3327 switch (TREE_CODE (t))
3330 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3338 switch (TREE_CODE (t))
3342 struct constraint_expr *c;
3344 tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
3345 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
3348 /* If we are not taking the address then make sure to process
3349 all subvariables we might access. */
3350 c = VEC_last (ce_s, *results);
3352 || c->type != SCALAR)
3355 vi = get_varinfo (c->var);
3357 if (!vi->is_full_var
3360 unsigned HOST_WIDE_INT size;
3361 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3362 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3365 for (; curr; curr = curr->next)
3367 if (curr->offset - vi->offset < size)
3369 struct constraint_expr cs = *c;
3371 VEC_safe_push (ce_s, heap, *results, &cs);
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 we can ignore it. */
3790 if (flags & EAF_UNUSED)
3793 /* As we compute ESCAPED context-insensitive we do not gain
3794 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3795 set. The argument would still get clobbered through the
3797 ??? We might get away with less (and more precise) constraints
3798 if using a temporary for transitively closing things. */
3799 if ((flags & EAF_NOCLOBBER)
3800 && (flags & EAF_NOESCAPE))
3802 varinfo_t uses = get_call_use_vi (stmt);
3803 if (!(flags & EAF_DIRECT))
3804 make_transitive_closure_constraints (uses);
3805 make_constraint_to (uses->id, arg);
3806 returns_uses = true;
3808 else if (flags & EAF_NOESCAPE)
3810 varinfo_t uses = get_call_use_vi (stmt);
3811 varinfo_t clobbers = get_call_clobber_vi (stmt);
3812 if (!(flags & EAF_DIRECT))
3814 make_transitive_closure_constraints (uses);
3815 make_transitive_closure_constraints (clobbers);
3817 make_constraint_to (uses->id, arg);
3818 make_constraint_to (clobbers->id, arg);
3819 returns_uses = true;
3822 make_escape_constraint (arg);
3825 /* If we added to the calls uses solution make sure we account for
3826 pointers to it to be returned. */
3829 rhsc.var = get_call_use_vi (stmt)->id;
3832 VEC_safe_push (ce_s, heap, *results, &rhsc);
3835 /* The static chain escapes as well. */
3836 if (gimple_call_chain (stmt))
3837 make_escape_constraint (gimple_call_chain (stmt));
3839 /* And if we applied NRV the address of the return slot escapes as well. */
3840 if (gimple_call_return_slot_opt_p (stmt)
3841 && gimple_call_lhs (stmt) != NULL_TREE
3842 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3844 VEC(ce_s, heap) *tmpc = NULL;
3845 struct constraint_expr lhsc, *c;
3846 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3847 lhsc.var = escaped_id;
3850 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3851 process_constraint (new_constraint (lhsc, *c));
3852 VEC_free(ce_s, heap, tmpc);
3855 /* Regular functions return nonlocal memory. */
3856 rhsc.var = nonlocal_id;
3859 VEC_safe_push (ce_s, heap, *results, &rhsc);
3862 /* For non-IPA mode, generate constraints necessary for a call
3863 that returns a pointer and assigns it to LHS. This simply makes
3864 the LHS point to global and escaped variables. */
3867 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3870 VEC(ce_s, heap) *lhsc = NULL;
3872 get_constraint_for (lhs, &lhsc);
3873 /* If the store is to a global decl make sure to
3874 add proper escape constraints. */
3875 lhs = get_base_address (lhs);
3878 && is_global_var (lhs))
3880 struct constraint_expr tmpc;
3881 tmpc.var = escaped_id;
3884 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3887 /* If the call returns an argument unmodified override the rhs
3889 flags = gimple_call_return_flags (stmt);
3890 if (flags & ERF_RETURNS_ARG
3891 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3895 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3896 get_constraint_for (arg, &rhsc);
3897 process_all_all_constraints (lhsc, rhsc);
3898 VEC_free (ce_s, heap, rhsc);
3900 else if (flags & ERF_NOALIAS)
3903 struct constraint_expr tmpc;
3905 vi = make_heapvar_for (get_vi_for_tree (lhs), "HEAP");
3906 /* We delay marking allocated storage global until we know if
3908 DECL_EXTERNAL (vi->decl) = 0;
3909 vi->is_global_var = 0;
3910 /* If this is not a real malloc call assume the memory was
3911 initialized and thus may point to global memory. All
3912 builtin functions with the malloc attribute behave in a sane way. */
3914 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3915 make_constraint_from (vi, nonlocal_id);
3918 tmpc.type = ADDRESSOF;
3919 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3922 process_all_all_constraints (lhsc, rhsc);
3924 VEC_free (ce_s, heap, lhsc);
3927 /* For non-IPA mode, generate constraints necessary for a call of a
3928 const function that returns a pointer in the statement STMT. */
3931 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3933 struct constraint_expr rhsc;
3936 /* Treat nested const functions the same as pure functions as far
3937 as the static chain is concerned. */
3938 if (gimple_call_chain (stmt))
3940 varinfo_t uses = get_call_use_vi (stmt);
3941 make_transitive_closure_constraints (uses);
3942 make_constraint_to (uses->id, gimple_call_chain (stmt));
3943 rhsc.var = uses->id;
3946 VEC_safe_push (ce_s, heap, *results, &rhsc);
3949 /* May return arguments. */
3950 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3952 tree arg = gimple_call_arg (stmt, k);
3953 VEC(ce_s, heap) *argc = NULL;
3955 struct constraint_expr *argp;
3956 get_constraint_for_rhs (arg, &argc);
3957 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3958 VEC_safe_push (ce_s, heap, *results, argp);
3959 VEC_free(ce_s, heap, argc);
3962 /* May return addresses of globals. */
3963 rhsc.var = nonlocal_id;
3965 rhsc.type = ADDRESSOF;
3966 VEC_safe_push (ce_s, heap, *results, &rhsc);
3969 /* For non-IPA mode, generate constraints necessary for a call to a
3970 pure function in statement STMT. */
3973 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3975 struct constraint_expr rhsc;
3977 varinfo_t uses = NULL;
3979 /* Memory reached from pointer arguments is call-used. */
3980 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3982 tree arg = gimple_call_arg (stmt, i);
3985 uses = get_call_use_vi (stmt);
3986 make_transitive_closure_constraints (uses);
3988 make_constraint_to (uses->id, arg);
3991 /* The static chain is used as well. */
3992 if (gimple_call_chain (stmt))
3996 uses = get_call_use_vi (stmt);
3997 make_transitive_closure_constraints (uses);
3999 make_constraint_to (uses->id, gimple_call_chain (stmt));
4002 /* Pure functions may return call-used and nonlocal memory. */
4005 rhsc.var = uses->id;
4008 VEC_safe_push (ce_s, heap, *results, &rhsc);
4010 rhsc.var = nonlocal_id;
4013 VEC_safe_push (ce_s, heap, *results, &rhsc);
4017 /* Return the varinfo for the callee of CALL. */
4020 get_fi_for_callee (gimple call)
4024 /* If we can directly resolve the function being called, do so.
4025 Otherwise, it must be some sort of indirect expression that
4026 we should still be able to handle. */
4027 decl = gimple_call_fndecl (call);
4029 return get_vi_for_tree (decl);
4031 decl = gimple_call_fn (call);
4032 /* The function can be either an SSA name pointer or,
4033 worse, an OBJ_TYPE_REF. In this case we have no
4034 clue and should be getting ANYFN (well, ANYTHING for now). */
4035 if (TREE_CODE (decl) == SSA_NAME)
4037 if (TREE_CODE (decl) == SSA_NAME
4038 && (TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
4039 || TREE_CODE (SSA_NAME_VAR (decl)) == RESULT_DECL)
4040 && SSA_NAME_IS_DEFAULT_DEF (decl))
4041 decl = SSA_NAME_VAR (decl);
4042 return get_vi_for_tree (decl);
4044 else if (TREE_CODE (decl) == INTEGER_CST
4045 || TREE_CODE (decl) == OBJ_TYPE_REF)
4046 return get_varinfo (anything_id);
4051 /* Walk statement T setting up aliasing constraints according to the
4052 references found in T. This function is the main part of the
4053 constraint builder. AI points to auxiliary alias information used
4054 when building alias sets and computing alias grouping heuristics. */
4057 find_func_aliases (gimple origt)
4060 VEC(ce_s, heap) *lhsc = NULL;
4061 VEC(ce_s, heap) *rhsc = NULL;
4062 struct constraint_expr *c;
4065 /* Now build constraints expressions. */
4066 if (gimple_code (t) == GIMPLE_PHI)
4071 /* For a phi node, assign all the arguments to
4073 get_constraint_for (gimple_phi_result (t), &lhsc);
4074 for (i = 0; i < gimple_phi_num_args (t); i++)
4076 tree strippedrhs = PHI_ARG_DEF (t, i);
4078 STRIP_NOPS (strippedrhs);
4079 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4081 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4083 struct constraint_expr *c2;
4084 while (VEC_length (ce_s, rhsc) > 0)
4086 c2 = VEC_last (ce_s, rhsc);
4087 process_constraint (new_constraint (*c, *c2));
4088 VEC_pop (ce_s, rhsc);
4093 /* In IPA mode, we need to generate constraints to pass call
4094 arguments through their calls. There are two cases,
4095 either a GIMPLE_CALL returning a value, or just a plain
4096 GIMPLE_CALL when we are not.
4098 In non-ipa mode, we need to generate constraints for each
4099 pointer passed by address. */
4100 else if (is_gimple_call (t))
4102 tree fndecl = gimple_call_fndecl (t);
4103 if (fndecl != NULL_TREE
4104 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4105 /* ??? All builtins that are handled here need to be handled
4106 in the alias-oracle query functions explicitly! */
4107 switch (DECL_FUNCTION_CODE (fndecl))
4109 /* All the following functions return a pointer to the same object
4110 as their first argument points to. The functions do not add
4111 to the ESCAPED solution. The functions make the first argument
4112 pointed to memory point to what the second argument pointed to
4113 memory points to. */
4114 case BUILT_IN_STRCPY:
4115 case BUILT_IN_STRNCPY:
4116 case BUILT_IN_BCOPY:
4117 case BUILT_IN_MEMCPY:
4118 case BUILT_IN_MEMMOVE:
4119 case BUILT_IN_MEMPCPY:
4120 case BUILT_IN_STPCPY:
4121 case BUILT_IN_STPNCPY:
4122 case BUILT_IN_STRCAT:
4123 case BUILT_IN_STRNCAT:
4125 tree res = gimple_call_lhs (t);
4126 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4127 == BUILT_IN_BCOPY ? 1 : 0));
4128 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4129 == BUILT_IN_BCOPY ? 0 : 1));
4130 if (res != NULL_TREE)
4132 get_constraint_for (res, &lhsc);
4133 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4134 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4135 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4136 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4138 get_constraint_for (dest, &rhsc);
4139 process_all_all_constraints (lhsc, rhsc);
4140 VEC_free (ce_s, heap, lhsc);
4141 VEC_free (ce_s, heap, rhsc);
4143 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4144 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4147 process_all_all_constraints (lhsc, rhsc);
4148 VEC_free (ce_s, heap, lhsc);
4149 VEC_free (ce_s, heap, rhsc);
4152 case BUILT_IN_MEMSET:
4154 tree res = gimple_call_lhs (t);
4155 tree dest = gimple_call_arg (t, 0);
4158 struct constraint_expr ac;
4159 if (res != NULL_TREE)
4161 get_constraint_for (res, &lhsc);
4162 get_constraint_for (dest, &rhsc);
4163 process_all_all_constraints (lhsc, rhsc);
4164 VEC_free (ce_s, heap, lhsc);
4165 VEC_free (ce_s, heap, rhsc);
4167 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4169 if (flag_delete_null_pointer_checks
4170 && integer_zerop (gimple_call_arg (t, 1)))
4172 ac.type = ADDRESSOF;
4173 ac.var = nothing_id;
4178 ac.var = integer_id;
4181 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4182 process_constraint (new_constraint (*lhsp, ac));
4183 VEC_free (ce_s, heap, lhsc);
4186 /* All the following functions do not return pointers, do not
4187 modify the points-to sets of memory reachable from their
4188 arguments and do not add to the ESCAPED solution. */
4189 case BUILT_IN_SINCOS:
4190 case BUILT_IN_SINCOSF:
4191 case BUILT_IN_SINCOSL:
4192 case BUILT_IN_FREXP:
4193 case BUILT_IN_FREXPF:
4194 case BUILT_IN_FREXPL:
4195 case BUILT_IN_GAMMA_R:
4196 case BUILT_IN_GAMMAF_R:
4197 case BUILT_IN_GAMMAL_R:
4198 case BUILT_IN_LGAMMA_R:
4199 case BUILT_IN_LGAMMAF_R:
4200 case BUILT_IN_LGAMMAL_R:
4202 case BUILT_IN_MODFF:
4203 case BUILT_IN_MODFL:
4204 case BUILT_IN_REMQUO:
4205 case BUILT_IN_REMQUOF:
4206 case BUILT_IN_REMQUOL:
4209 /* Trampolines are special - they set up passing the static
4211 case BUILT_IN_INIT_TRAMPOLINE:
4213 tree tramp = gimple_call_arg (t, 0);
4214 tree nfunc = gimple_call_arg (t, 1);
4215 tree frame = gimple_call_arg (t, 2);
4217 struct constraint_expr lhs, *rhsp;
4220 varinfo_t nfi = NULL;
4221 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4222 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4225 lhs = get_function_part_constraint (nfi, fi_static_chain);
4226 get_constraint_for (frame, &rhsc);
4227 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4228 process_constraint (new_constraint (lhs, *rhsp));
4229 VEC_free (ce_s, heap, rhsc);
4231 /* Make the frame point to the function for
4232 the trampoline adjustment call. */
4233 get_constraint_for (tramp, &lhsc);
4235 get_constraint_for (nfunc, &rhsc);
4236 process_all_all_constraints (lhsc, rhsc);
4237 VEC_free (ce_s, heap, rhsc);
4238 VEC_free (ce_s, heap, lhsc);
4243 /* Else fallthru to generic handling which will let
4244 the frame escape. */
4247 case BUILT_IN_ADJUST_TRAMPOLINE:
4249 tree tramp = gimple_call_arg (t, 0);
4250 tree res = gimple_call_lhs (t);
4251 if (in_ipa_mode && res)
4253 get_constraint_for (res, &lhsc);
4254 get_constraint_for (tramp, &rhsc);
4256 process_all_all_constraints (lhsc, rhsc);
4257 VEC_free (ce_s, heap, rhsc);
4258 VEC_free (ce_s, heap, lhsc);
4262 /* Variadic argument handling needs to be handled in IPA
4264 case BUILT_IN_VA_START:
4268 tree valist = gimple_call_arg (t, 0);
4269 struct constraint_expr rhs, *lhsp;
4271 /* The va_list gets access to pointers in variadic
4273 fi = lookup_vi_for_tree (cfun->decl);
4274 gcc_assert (fi != NULL);
4275 get_constraint_for (valist, &lhsc);
4277 rhs = get_function_part_constraint (fi, ~0);
4278 rhs.type = ADDRESSOF;
4279 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4280 process_constraint (new_constraint (*lhsp, rhs));
4281 VEC_free (ce_s, heap, lhsc);
4282 /* va_list is clobbered. */
4283 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4288 /* va_end doesn't have any effect that matters. */
4289 case BUILT_IN_VA_END:
4291 /* Alternate return. Simply give up for now. */
4292 case BUILT_IN_RETURN:
4296 || !(fi = get_vi_for_tree (cfun->decl)))
4297 make_constraint_from (get_varinfo (escaped_id), anything_id);
4298 else if (in_ipa_mode
4301 struct constraint_expr lhs, rhs;
4302 lhs = get_function_part_constraint (fi, fi_result);
4303 rhs.var = anything_id;
4306 process_constraint (new_constraint (lhs, rhs));
4310 /* printf-style functions may have hooks to set pointers to
4311 point to somewhere into the generated string. Leave them
4312 for a later excercise... */
4314 /* Fallthru to general call handling. */;
4318 && (!(fi = lookup_vi_for_tree (fndecl))
4319 || !fi->is_fn_info)))
4321 VEC(ce_s, heap) *rhsc = NULL;
4322 int flags = gimple_call_flags (t);
4324 /* Const functions can return their arguments and addresses
4325 of global memory but not of escaped memory. */
4326 if (flags & (ECF_CONST|ECF_NOVOPS))
4328 if (gimple_call_lhs (t))
4329 handle_const_call (t, &rhsc);
4331 /* Pure functions can return addresses in and of memory
4332 reachable from their arguments, but they are not an escape
4333 point for reachable memory of their arguments. */
4334 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4335 handle_pure_call (t, &rhsc);
4337 handle_rhs_call (t, &rhsc);
4338 if (gimple_call_lhs (t))
4339 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4340 VEC_free (ce_s, heap, rhsc);
4347 fi = get_fi_for_callee (t);
4349 /* Assign all the passed arguments to the appropriate incoming
4350 parameters of the function. */
4351 for (j = 0; j < gimple_call_num_args (t); j++)
4353 struct constraint_expr lhs ;
4354 struct constraint_expr *rhsp;
4355 tree arg = gimple_call_arg (t, j);
4357 get_constraint_for_rhs (arg, &rhsc);
4358 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4359 while (VEC_length (ce_s, rhsc) != 0)
4361 rhsp = VEC_last (ce_s, rhsc);
4362 process_constraint (new_constraint (lhs, *rhsp));
4363 VEC_pop (ce_s, rhsc);
4367 /* If we are returning a value, assign it to the result. */
4368 lhsop = gimple_call_lhs (t);
4371 struct constraint_expr rhs;
4372 struct constraint_expr *lhsp;
4374 get_constraint_for (lhsop, &lhsc);
4375 rhs = get_function_part_constraint (fi, fi_result);
4377 && DECL_RESULT (fndecl)
4378 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4380 VEC(ce_s, heap) *tem = NULL;
4381 VEC_safe_push (ce_s, heap, tem, &rhs);
4383 rhs = *VEC_index (ce_s, tem, 0);
4384 VEC_free(ce_s, heap, tem);
4386 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4387 process_constraint (new_constraint (*lhsp, rhs));
4390 /* If we pass the result decl by reference, honor that. */
4393 && DECL_RESULT (fndecl)
4394 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4396 struct constraint_expr lhs;
4397 struct constraint_expr *rhsp;
4399 get_constraint_for_address_of (lhsop, &rhsc);
4400 lhs = get_function_part_constraint (fi, fi_result);
4401 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4402 process_constraint (new_constraint (lhs, *rhsp));
4403 VEC_free (ce_s, heap, rhsc);
4406 /* If we use a static chain, pass it along. */
4407 if (gimple_call_chain (t))
4409 struct constraint_expr lhs;
4410 struct constraint_expr *rhsp;
4412 get_constraint_for (gimple_call_chain (t), &rhsc);
4413 lhs = get_function_part_constraint (fi, fi_static_chain);
4414 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4415 process_constraint (new_constraint (lhs, *rhsp));
4419 /* Otherwise, just a regular assignment statement. Only care about
4420 operations with pointer result, others are dealt with as escape
4421 points if they have pointer operands. */
4422 else if (is_gimple_assign (t))
4424 /* Otherwise, just a regular assignment statement. */
4425 tree lhsop = gimple_assign_lhs (t);
4426 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4428 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4429 do_structure_copy (lhsop, rhsop);
4432 get_constraint_for (lhsop, &lhsc);
4434 if (gimple_assign_rhs_code (t) == POINTER_PLUS_EXPR)
4435 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4436 gimple_assign_rhs2 (t), &rhsc);
4437 else if (gimple_assign_rhs_code (t) == BIT_AND_EXPR
4438 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4440 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4441 the pointer. Handle it by offsetting it by UNKNOWN. */
4442 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4445 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
4446 && !(POINTER_TYPE_P (gimple_expr_type (t))
4447 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4448 || gimple_assign_single_p (t))
4449 get_constraint_for_rhs (rhsop, &rhsc);
4452 /* All other operations are merges. */
4453 VEC (ce_s, heap) *tmp = NULL;
4454 struct constraint_expr *rhsp;
4456 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4457 for (i = 2; i < gimple_num_ops (t); ++i)
4459 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4460 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4461 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4462 VEC_truncate (ce_s, tmp, 0);
4464 VEC_free (ce_s, heap, tmp);
4466 process_all_all_constraints (lhsc, rhsc);
4468 /* If there is a store to a global variable the rhs escapes. */
4469 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4471 && is_global_var (lhsop)
4473 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4474 make_escape_constraint (rhsop);
4475 /* If this is a conversion of a non-restrict pointer to a
4476 restrict pointer track it with a new heapvar. */
4477 else if (gimple_assign_cast_p (t)
4478 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4479 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4480 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4481 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4482 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4485 /* Handle escapes through return. */
4486 else if (gimple_code (t) == GIMPLE_RETURN
4487 && gimple_return_retval (t) != NULL_TREE)
4491 || !(fi = get_vi_for_tree (cfun->decl)))
4492 make_escape_constraint (gimple_return_retval (t));
4493 else if (in_ipa_mode
4496 struct constraint_expr lhs ;
4497 struct constraint_expr *rhsp;
4500 lhs = get_function_part_constraint (fi, fi_result);
4501 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4502 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4503 process_constraint (new_constraint (lhs, *rhsp));
4506 /* Handle asms conservatively by adding escape constraints to everything. */
4507 else if (gimple_code (t) == GIMPLE_ASM)
4509 unsigned i, noutputs;
4510 const char **oconstraints;
4511 const char *constraint;
4512 bool allows_mem, allows_reg, is_inout;
4514 noutputs = gimple_asm_noutputs (t);
4515 oconstraints = XALLOCAVEC (const char *, noutputs);
4517 for (i = 0; i < noutputs; ++i)
4519 tree link = gimple_asm_output_op (t, i);
4520 tree op = TREE_VALUE (link);
4522 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4523 oconstraints[i] = constraint;
4524 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4525 &allows_reg, &is_inout);
4527 /* A memory constraint makes the address of the operand escape. */
4528 if (!allows_reg && allows_mem)
4529 make_escape_constraint (build_fold_addr_expr (op));
4531 /* The asm may read global memory, so outputs may point to
4532 any global memory. */
4535 VEC(ce_s, heap) *lhsc = NULL;
4536 struct constraint_expr rhsc, *lhsp;
4538 get_constraint_for (op, &lhsc);
4539 rhsc.var = nonlocal_id;
4542 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4543 process_constraint (new_constraint (*lhsp, rhsc));
4544 VEC_free (ce_s, heap, lhsc);
4547 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4549 tree link = gimple_asm_input_op (t, i);
4550 tree op = TREE_VALUE (link);
4552 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4554 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4555 &allows_mem, &allows_reg);
4557 /* A memory constraint makes the address of the operand escape. */
4558 if (!allows_reg && allows_mem)
4559 make_escape_constraint (build_fold_addr_expr (op));
4560 /* Strictly we'd only need the constraint to ESCAPED if
4561 the asm clobbers memory, otherwise using something
4562 along the lines of per-call clobbers/uses would be enough. */
4564 make_escape_constraint (op);
4568 VEC_free (ce_s, heap, rhsc);
4569 VEC_free (ce_s, heap, lhsc);
4573 /* Create a constraint adding to the clobber set of FI the memory
4574 pointed to by PTR. */
4577 process_ipa_clobber (varinfo_t fi, tree ptr)
4579 VEC(ce_s, heap) *ptrc = NULL;
4580 struct constraint_expr *c, lhs;
4582 get_constraint_for_rhs (ptr, &ptrc);
4583 lhs = get_function_part_constraint (fi, fi_clobbers);
4584 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4585 process_constraint (new_constraint (lhs, *c));
4586 VEC_free (ce_s, heap, ptrc);
4589 /* Walk statement T setting up clobber and use constraints according to the
4590 references found in T. This function is a main part of the
4591 IPA constraint builder. */
4594 find_func_clobbers (gimple origt)
4597 VEC(ce_s, heap) *lhsc = NULL;
4598 VEC(ce_s, heap) *rhsc = NULL;
4601 /* Add constraints for clobbered/used in IPA mode.
4602 We are not interested in what automatic variables are clobbered
4603 or used as we only use the information in the caller to which
4604 they do not escape. */
4605 gcc_assert (in_ipa_mode);
4607 /* If the stmt refers to memory in any way it better had a VUSE. */
4608 if (gimple_vuse (t) == NULL_TREE)
4611 /* We'd better have function information for the current function. */
4612 fi = lookup_vi_for_tree (cfun->decl);
4613 gcc_assert (fi != NULL);
4615 /* Account for stores in assignments and calls. */
4616 if (gimple_vdef (t) != NULL_TREE
4617 && gimple_has_lhs (t))
4619 tree lhs = gimple_get_lhs (t);
4621 while (handled_component_p (tem))
4622 tem = TREE_OPERAND (tem, 0);
4624 && !auto_var_in_fn_p (tem, cfun->decl))
4625 || INDIRECT_REF_P (tem)
4626 || (TREE_CODE (tem) == MEM_REF
4627 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4629 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4631 struct constraint_expr lhsc, *rhsp;
4633 lhsc = get_function_part_constraint (fi, fi_clobbers);
4634 get_constraint_for_address_of (lhs, &rhsc);
4635 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4636 process_constraint (new_constraint (lhsc, *rhsp));
4637 VEC_free (ce_s, heap, rhsc);
4641 /* Account for uses in assigments and returns. */
4642 if (gimple_assign_single_p (t)
4643 || (gimple_code (t) == GIMPLE_RETURN
4644 && gimple_return_retval (t) != NULL_TREE))
4646 tree rhs = (gimple_assign_single_p (t)
4647 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4649 while (handled_component_p (tem))
4650 tem = TREE_OPERAND (tem, 0);
4652 && !auto_var_in_fn_p (tem, cfun->decl))
4653 || INDIRECT_REF_P (tem)
4654 || (TREE_CODE (tem) == MEM_REF
4655 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4657 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4659 struct constraint_expr lhs, *rhsp;
4661 lhs = get_function_part_constraint (fi, fi_uses);
4662 get_constraint_for_address_of (rhs, &rhsc);
4663 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4664 process_constraint (new_constraint (lhs, *rhsp));
4665 VEC_free (ce_s, heap, rhsc);
4669 if (is_gimple_call (t))
4671 varinfo_t cfi = NULL;
4672 tree decl = gimple_call_fndecl (t);
4673 struct constraint_expr lhs, rhs;
4676 /* For builtins we do not have separate function info. For those
4677 we do not generate escapes for we have to generate clobbers/uses. */
4679 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4680 switch (DECL_FUNCTION_CODE (decl))
4682 /* The following functions use and clobber memory pointed to
4683 by their arguments. */
4684 case BUILT_IN_STRCPY:
4685 case BUILT_IN_STRNCPY:
4686 case BUILT_IN_BCOPY:
4687 case BUILT_IN_MEMCPY:
4688 case BUILT_IN_MEMMOVE:
4689 case BUILT_IN_MEMPCPY:
4690 case BUILT_IN_STPCPY:
4691 case BUILT_IN_STPNCPY:
4692 case BUILT_IN_STRCAT:
4693 case BUILT_IN_STRNCAT:
4695 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4696 == BUILT_IN_BCOPY ? 1 : 0));
4697 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4698 == BUILT_IN_BCOPY ? 0 : 1));
4700 struct constraint_expr *rhsp, *lhsp;
4701 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4702 lhs = get_function_part_constraint (fi, fi_clobbers);
4703 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4704 process_constraint (new_constraint (lhs, *lhsp));
4705 VEC_free (ce_s, heap, lhsc);
4706 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4707 lhs = get_function_part_constraint (fi, fi_uses);
4708 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4709 process_constraint (new_constraint (lhs, *rhsp));
4710 VEC_free (ce_s, heap, rhsc);
4713 /* The following function clobbers memory pointed to by
4715 case BUILT_IN_MEMSET:
4717 tree dest = gimple_call_arg (t, 0);
4720 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4721 lhs = get_function_part_constraint (fi, fi_clobbers);
4722 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4723 process_constraint (new_constraint (lhs, *lhsp));
4724 VEC_free (ce_s, heap, lhsc);
4727 /* The following functions clobber their second and third
4729 case BUILT_IN_SINCOS:
4730 case BUILT_IN_SINCOSF:
4731 case BUILT_IN_SINCOSL:
4733 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4734 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4737 /* The following functions clobber their second argument. */
4738 case BUILT_IN_FREXP:
4739 case BUILT_IN_FREXPF:
4740 case BUILT_IN_FREXPL:
4741 case BUILT_IN_LGAMMA_R:
4742 case BUILT_IN_LGAMMAF_R:
4743 case BUILT_IN_LGAMMAL_R:
4744 case BUILT_IN_GAMMA_R:
4745 case BUILT_IN_GAMMAF_R:
4746 case BUILT_IN_GAMMAL_R:
4748 case BUILT_IN_MODFF:
4749 case BUILT_IN_MODFL:
4751 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4754 /* The following functions clobber their third argument. */
4755 case BUILT_IN_REMQUO:
4756 case BUILT_IN_REMQUOF:
4757 case BUILT_IN_REMQUOL:
4759 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4762 /* The following functions neither read nor clobber memory. */
4765 /* Trampolines are of no interest to us. */
4766 case BUILT_IN_INIT_TRAMPOLINE:
4767 case BUILT_IN_ADJUST_TRAMPOLINE:
4769 case BUILT_IN_VA_START:
4770 case BUILT_IN_VA_END:
4772 /* printf-style functions may have hooks to set pointers to
4773 point to somewhere into the generated string. Leave them
4774 for a later excercise... */
4776 /* Fallthru to general call handling. */;
4779 /* Parameters passed by value are used. */
4780 lhs = get_function_part_constraint (fi, fi_uses);
4781 for (i = 0; i < gimple_call_num_args (t); i++)
4783 struct constraint_expr *rhsp;
4784 tree arg = gimple_call_arg (t, i);
4786 if (TREE_CODE (arg) == SSA_NAME
4787 || is_gimple_min_invariant (arg))
4790 get_constraint_for_address_of (arg, &rhsc);
4791 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4792 process_constraint (new_constraint (lhs, *rhsp));
4793 VEC_free (ce_s, heap, rhsc);
4796 /* Build constraints for propagating clobbers/uses along the
4798 cfi = get_fi_for_callee (t);
4799 if (cfi->id == anything_id)
4801 if (gimple_vdef (t))
4802 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4804 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4809 /* For callees without function info (that's external functions),
4810 ESCAPED is clobbered and used. */
4811 if (gimple_call_fndecl (t)
4812 && !cfi->is_fn_info)
4816 if (gimple_vdef (t))
4817 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4819 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4821 /* Also honor the call statement use/clobber info. */
4822 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4823 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4825 if ((vi = lookup_call_use_vi (t)) != NULL)
4826 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4831 /* Otherwise the caller clobbers and uses what the callee does.
4832 ??? This should use a new complex constraint that filters
4833 local variables of the callee. */
4834 if (gimple_vdef (t))
4836 lhs = get_function_part_constraint (fi, fi_clobbers);
4837 rhs = get_function_part_constraint (cfi, fi_clobbers);
4838 process_constraint (new_constraint (lhs, rhs));
4840 lhs = get_function_part_constraint (fi, fi_uses);
4841 rhs = get_function_part_constraint (cfi, fi_uses);
4842 process_constraint (new_constraint (lhs, rhs));
4844 else if (gimple_code (t) == GIMPLE_ASM)
4846 /* ??? Ick. We can do better. */
4847 if (gimple_vdef (t))
4848 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4850 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4854 VEC_free (ce_s, heap, rhsc);
4858 /* Find the first varinfo in the same variable as START that overlaps with
4859 OFFSET. Return NULL if we can't find one. */
4862 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4864 /* If the offset is outside of the variable, bail out. */
4865 if (offset >= start->fullsize)
4868 /* If we cannot reach offset from start, lookup the first field
4869 and start from there. */
4870 if (start->offset > offset)
4871 start = lookup_vi_for_tree (start->decl);
4875 /* We may not find a variable in the field list with the actual
4876 offset when when we have glommed a structure to a variable.
4877 In that case, however, offset should still be within the size
4879 if (offset >= start->offset
4880 && (offset - start->offset) < start->size)
4889 /* Find the first varinfo in the same variable as START that overlaps with
4890 OFFSET. If there is no such varinfo the varinfo directly preceding
4891 OFFSET is returned. */
4894 first_or_preceding_vi_for_offset (varinfo_t start,
4895 unsigned HOST_WIDE_INT offset)
4897 /* If we cannot reach offset from start, lookup the first field
4898 and start from there. */
4899 if (start->offset > offset)
4900 start = lookup_vi_for_tree (start->decl);
4902 /* We may not find a variable in the field list with the actual
4903 offset when when we have glommed a structure to a variable.
4904 In that case, however, offset should still be within the size
4906 If we got beyond the offset we look for return the field
4907 directly preceding offset which may be the last field. */
4909 && offset >= start->offset
4910 && !((offset - start->offset) < start->size))
4911 start = start->next;
4917 /* This structure is used during pushing fields onto the fieldstack
4918 to track the offset of the field, since bitpos_of_field gives it
4919 relative to its immediate containing type, and we want it relative
4920 to the ultimate containing object. */
4924 /* Offset from the base of the base containing object to this field. */
4925 HOST_WIDE_INT offset;
4927 /* Size, in bits, of the field. */
4928 unsigned HOST_WIDE_INT size;
4930 unsigned has_unknown_size : 1;
4932 unsigned must_have_pointers : 1;
4934 unsigned may_have_pointers : 1;
4936 unsigned only_restrict_pointers : 1;
4938 typedef struct fieldoff fieldoff_s;
4940 DEF_VEC_O(fieldoff_s);
4941 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4943 /* qsort comparison function for two fieldoff's PA and PB */
4946 fieldoff_compare (const void *pa, const void *pb)
4948 const fieldoff_s *foa = (const fieldoff_s *)pa;
4949 const fieldoff_s *fob = (const fieldoff_s *)pb;
4950 unsigned HOST_WIDE_INT foasize, fobsize;
4952 if (foa->offset < fob->offset)
4954 else if (foa->offset > fob->offset)
4957 foasize = foa->size;
4958 fobsize = fob->size;
4959 if (foasize < fobsize)
4961 else if (foasize > fobsize)
4966 /* Sort a fieldstack according to the field offset and sizes. */
4968 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4970 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
4973 /* Return true if V is a tree that we can have subvars for.
4974 Normally, this is any aggregate type. Also complex
4975 types which are not gimple registers can have subvars. */
4978 var_can_have_subvars (const_tree v)
4980 /* Volatile variables should never have subvars. */
4981 if (TREE_THIS_VOLATILE (v))
4984 /* Non decls or memory tags can never have subvars. */
4988 /* Aggregates without overlapping fields can have subvars. */
4989 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4995 /* Return true if T is a type that does contain pointers. */
4998 type_must_have_pointers (tree type)
5000 if (POINTER_TYPE_P (type))
5003 if (TREE_CODE (type) == ARRAY_TYPE)
5004 return type_must_have_pointers (TREE_TYPE (type));
5006 /* A function or method can have pointers as arguments, so track
5007 those separately. */
5008 if (TREE_CODE (type) == FUNCTION_TYPE
5009 || TREE_CODE (type) == METHOD_TYPE)
5016 field_must_have_pointers (tree t)
5018 return type_must_have_pointers (TREE_TYPE (t));
5021 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5022 the fields of TYPE onto fieldstack, recording their offsets along
5025 OFFSET is used to keep track of the offset in this entire
5026 structure, rather than just the immediately containing structure.
5027 Returns false if the caller is supposed to handle the field we
5031 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5032 HOST_WIDE_INT offset)
5035 bool empty_p = true;
5037 if (TREE_CODE (type) != RECORD_TYPE)
5040 /* If the vector of fields is growing too big, bail out early.
5041 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5043 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5046 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5047 if (TREE_CODE (field) == FIELD_DECL)
5050 HOST_WIDE_INT foff = bitpos_of_field (field);
5052 if (!var_can_have_subvars (field)
5053 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5054 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5056 else if (!push_fields_onto_fieldstack
5057 (TREE_TYPE (field), fieldstack, offset + foff)
5058 && (DECL_SIZE (field)
5059 && !integer_zerop (DECL_SIZE (field))))
5060 /* Empty structures may have actual size, like in C++. So
5061 see if we didn't push any subfields and the size is
5062 nonzero, push the field onto the stack. */
5067 fieldoff_s *pair = NULL;
5068 bool has_unknown_size = false;
5069 bool must_have_pointers_p;
5071 if (!VEC_empty (fieldoff_s, *fieldstack))
5072 pair = VEC_last (fieldoff_s, *fieldstack);
5074 if (!DECL_SIZE (field)
5075 || !host_integerp (DECL_SIZE (field), 1))
5076 has_unknown_size = true;
5078 /* If adjacent fields do not contain pointers merge them. */
5079 must_have_pointers_p = field_must_have_pointers (field);
5081 && !has_unknown_size
5082 && !must_have_pointers_p
5083 && !pair->must_have_pointers
5084 && !pair->has_unknown_size
5085 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5087 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5091 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5092 pair->offset = offset + foff;
5093 pair->has_unknown_size = has_unknown_size;
5094 if (!has_unknown_size)
5095 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5098 pair->must_have_pointers = must_have_pointers_p;
5099 pair->may_have_pointers = true;
5100 pair->only_restrict_pointers
5101 = (!has_unknown_size
5102 && POINTER_TYPE_P (TREE_TYPE (field))
5103 && TYPE_RESTRICT (TREE_TYPE (field)));
5113 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5114 if it is a varargs function. */
5117 count_num_arguments (tree decl, bool *is_varargs)
5119 unsigned int num = 0;
5122 /* Capture named arguments for K&R functions. They do not
5123 have a prototype and thus no TYPE_ARG_TYPES. */
5124 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5127 /* Check if the function has variadic arguments. */
5128 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5129 if (TREE_VALUE (t) == void_type_node)
5137 /* Creation function node for DECL, using NAME, and return the index
5138 of the variable we've created for the function. */
5141 create_function_info_for (tree decl, const char *name)
5143 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5144 varinfo_t vi, prev_vi;
5147 bool is_varargs = false;
5148 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5150 /* Create the variable info. */
5152 vi = new_var_info (decl, name);
5155 vi->fullsize = fi_parm_base + num_args;
5157 vi->may_have_pointers = false;
5160 insert_vi_for_tree (vi->decl, vi);
5164 /* Create a variable for things the function clobbers and one for
5165 things the function uses. */
5167 varinfo_t clobbervi, usevi;
5168 const char *newname;
5171 asprintf (&tempname, "%s.clobber", name);
5172 newname = ggc_strdup (tempname);
5175 clobbervi = new_var_info (NULL, newname);
5176 clobbervi->offset = fi_clobbers;
5177 clobbervi->size = 1;
5178 clobbervi->fullsize = vi->fullsize;
5179 clobbervi->is_full_var = true;
5180 clobbervi->is_global_var = false;
5181 gcc_assert (prev_vi->offset < clobbervi->offset);
5182 prev_vi->next = clobbervi;
5183 prev_vi = clobbervi;
5185 asprintf (&tempname, "%s.use", name);
5186 newname = ggc_strdup (tempname);
5189 usevi = new_var_info (NULL, newname);
5190 usevi->offset = fi_uses;
5192 usevi->fullsize = vi->fullsize;
5193 usevi->is_full_var = true;
5194 usevi->is_global_var = false;
5195 gcc_assert (prev_vi->offset < usevi->offset);
5196 prev_vi->next = usevi;
5200 /* And one for the static chain. */
5201 if (fn->static_chain_decl != NULL_TREE)
5204 const char *newname;
5207 asprintf (&tempname, "%s.chain", name);
5208 newname = ggc_strdup (tempname);
5211 chainvi = new_var_info (fn->static_chain_decl, newname);
5212 chainvi->offset = fi_static_chain;
5214 chainvi->fullsize = vi->fullsize;
5215 chainvi->is_full_var = true;
5216 chainvi->is_global_var = false;
5217 gcc_assert (prev_vi->offset < chainvi->offset);
5218 prev_vi->next = chainvi;
5220 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5223 /* Create a variable for the return var. */
5224 if (DECL_RESULT (decl) != NULL
5225 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5228 const char *newname;
5230 tree resultdecl = decl;
5232 if (DECL_RESULT (decl))
5233 resultdecl = DECL_RESULT (decl);
5235 asprintf (&tempname, "%s.result", name);
5236 newname = ggc_strdup (tempname);
5239 resultvi = new_var_info (resultdecl, newname);
5240 resultvi->offset = fi_result;
5242 resultvi->fullsize = vi->fullsize;
5243 resultvi->is_full_var = true;
5244 if (DECL_RESULT (decl))
5245 resultvi->may_have_pointers = true;
5246 gcc_assert (prev_vi->offset < resultvi->offset);
5247 prev_vi->next = resultvi;
5249 if (DECL_RESULT (decl))
5250 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5253 /* Set up variables for each argument. */
5254 arg = DECL_ARGUMENTS (decl);
5255 for (i = 0; i < num_args; i++)
5258 const char *newname;
5260 tree argdecl = decl;
5265 asprintf (&tempname, "%s.arg%d", name, i);
5266 newname = ggc_strdup (tempname);
5269 argvi = new_var_info (argdecl, newname);
5270 argvi->offset = fi_parm_base + i;
5272 argvi->is_full_var = true;
5273 argvi->fullsize = vi->fullsize;
5275 argvi->may_have_pointers = true;
5276 gcc_assert (prev_vi->offset < argvi->offset);
5277 prev_vi->next = argvi;
5281 insert_vi_for_tree (arg, argvi);
5282 arg = DECL_CHAIN (arg);
5286 /* Add one representative for all further args. */
5290 const char *newname;
5294 asprintf (&tempname, "%s.varargs", name);
5295 newname = ggc_strdup (tempname);
5298 /* We need sth that can be pointed to for va_start. */
5299 decl = create_tmp_var_raw (ptr_type_node, name);
5302 argvi = new_var_info (decl, newname);
5303 argvi->offset = fi_parm_base + num_args;
5305 argvi->is_full_var = true;
5306 argvi->is_heap_var = true;
5307 argvi->fullsize = vi->fullsize;
5308 gcc_assert (prev_vi->offset < argvi->offset);
5309 prev_vi->next = argvi;
5317 /* Return true if FIELDSTACK contains fields that overlap.
5318 FIELDSTACK is assumed to be sorted by offset. */
5321 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5323 fieldoff_s *fo = NULL;
5325 HOST_WIDE_INT lastoffset = -1;
5327 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5329 if (fo->offset == lastoffset)
5331 lastoffset = fo->offset;
5336 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5337 This will also create any varinfo structures necessary for fields
5341 create_variable_info_for_1 (tree decl, const char *name)
5343 varinfo_t vi, newvi;
5344 tree decl_type = TREE_TYPE (decl);
5345 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5346 VEC (fieldoff_s,heap) *fieldstack = NULL;
5351 || !host_integerp (declsize, 1))
5353 vi = new_var_info (decl, name);
5357 vi->is_unknown_size_var = true;
5358 vi->is_full_var = true;
5359 vi->may_have_pointers = true;
5363 /* Collect field information. */
5364 if (use_field_sensitive
5365 && var_can_have_subvars (decl)
5366 /* ??? Force us to not use subfields for global initializers
5367 in IPA mode. Else we'd have to parse arbitrary initializers. */
5369 && is_global_var (decl)
5370 && DECL_INITIAL (decl)))
5372 fieldoff_s *fo = NULL;
5373 bool notokay = false;
5376 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5378 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5379 if (fo->has_unknown_size
5386 /* We can't sort them if we have a field with a variable sized type,
5387 which will make notokay = true. In that case, we are going to return
5388 without creating varinfos for the fields anyway, so sorting them is a
5392 sort_fieldstack (fieldstack);
5393 /* Due to some C++ FE issues, like PR 22488, we might end up
5394 what appear to be overlapping fields even though they,
5395 in reality, do not overlap. Until the C++ FE is fixed,
5396 we will simply disable field-sensitivity for these cases. */
5397 notokay = check_for_overlaps (fieldstack);
5401 VEC_free (fieldoff_s, heap, fieldstack);
5404 /* If we didn't end up collecting sub-variables create a full
5405 variable for the decl. */
5406 if (VEC_length (fieldoff_s, fieldstack) <= 1
5407 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5409 vi = new_var_info (decl, name);
5411 vi->may_have_pointers = true;
5412 vi->fullsize = TREE_INT_CST_LOW (declsize);
5413 vi->size = vi->fullsize;
5414 vi->is_full_var = true;
5415 VEC_free (fieldoff_s, heap, fieldstack);
5419 vi = new_var_info (decl, name);
5420 vi->fullsize = TREE_INT_CST_LOW (declsize);
5421 for (i = 0, newvi = vi;
5422 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5423 ++i, newvi = newvi->next)
5425 const char *newname = "NULL";
5430 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5431 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5432 newname = ggc_strdup (tempname);
5435 newvi->name = newname;
5436 newvi->offset = fo->offset;
5437 newvi->size = fo->size;
5438 newvi->fullsize = vi->fullsize;
5439 newvi->may_have_pointers = fo->may_have_pointers;
5440 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5441 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5442 newvi->next = new_var_info (decl, name);
5445 VEC_free (fieldoff_s, heap, fieldstack);
5451 create_variable_info_for (tree decl, const char *name)
5453 varinfo_t vi = create_variable_info_for_1 (decl, name);
5454 unsigned int id = vi->id;
5456 insert_vi_for_tree (decl, vi);
5458 /* Create initial constraints for globals. */
5459 for (; vi; vi = vi->next)
5461 if (!vi->may_have_pointers
5462 || !vi->is_global_var)
5465 /* Mark global restrict qualified pointers. */
5466 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5467 && TYPE_RESTRICT (TREE_TYPE (decl)))
5468 || vi->only_restrict_pointers)
5469 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5471 /* For escaped variables initialize them from nonlocal. */
5473 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5474 make_copy_constraint (vi, nonlocal_id);
5476 /* If this is a global variable with an initializer and we are in
5477 IPA mode generate constraints for it. In non-IPA mode
5478 the initializer from nonlocal is all we need. */
5480 && DECL_INITIAL (decl))
5482 VEC (ce_s, heap) *rhsc = NULL;
5483 struct constraint_expr lhs, *rhsp;
5485 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5489 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5490 process_constraint (new_constraint (lhs, *rhsp));
5491 /* If this is a variable that escapes from the unit
5492 the initializer escapes as well. */
5493 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5495 lhs.var = escaped_id;
5498 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5499 process_constraint (new_constraint (lhs, *rhsp));
5501 VEC_free (ce_s, heap, rhsc);
5508 /* Print out the points-to solution for VAR to FILE. */
5511 dump_solution_for_var (FILE *file, unsigned int var)
5513 varinfo_t vi = get_varinfo (var);
5517 /* Dump the solution for unified vars anyway, this avoids difficulties
5518 in scanning dumps in the testsuite. */
5519 fprintf (file, "%s = { ", vi->name);
5520 vi = get_varinfo (find (var));
5521 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5522 fprintf (file, "%s ", get_varinfo (i)->name);
5523 fprintf (file, "}");
5525 /* But note when the variable was unified. */
5527 fprintf (file, " same as %s", vi->name);
5529 fprintf (file, "\n");
5532 /* Print the points-to solution for VAR to stdout. */
5535 debug_solution_for_var (unsigned int var)
5537 dump_solution_for_var (stdout, var);
5540 /* Create varinfo structures for all of the variables in the
5541 function for intraprocedural mode. */
5544 intra_create_variable_infos (void)
5548 /* For each incoming pointer argument arg, create the constraint ARG
5549 = NONLOCAL or a dummy variable if it is a restrict qualified
5550 passed-by-reference argument. */
5551 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5555 /* For restrict qualified pointers to objects passed by
5556 reference build a real representative for the pointed-to object. */
5557 if (DECL_BY_REFERENCE (t)
5558 && POINTER_TYPE_P (TREE_TYPE (t))
5559 && TYPE_RESTRICT (TREE_TYPE (t)))
5561 struct constraint_expr lhsc, rhsc;
5563 tree heapvar = heapvar_lookup (t, 0);
5564 if (heapvar == NULL_TREE)
5567 heapvar = create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t)),
5569 DECL_EXTERNAL (heapvar) = 1;
5570 heapvar_insert (t, 0, heapvar);
5571 ann = get_var_ann (heapvar);
5572 ann->is_heapvar = 1;
5574 if (gimple_referenced_vars (cfun))
5575 add_referenced_var (heapvar);
5576 lhsc.var = get_vi_for_tree (t)->id;
5579 rhsc.var = (vi = get_vi_for_tree (heapvar))->id;
5580 rhsc.type = ADDRESSOF;
5582 process_constraint (new_constraint (lhsc, rhsc));
5583 vi->is_restrict_var = 1;
5587 for (p = get_vi_for_tree (t); p; p = p->next)
5589 if (p->may_have_pointers)
5590 make_constraint_from (p, nonlocal_id);
5591 if (p->only_restrict_pointers)
5592 make_constraint_from_restrict (p, "PARM_RESTRICT");
5594 if (POINTER_TYPE_P (TREE_TYPE (t))
5595 && TYPE_RESTRICT (TREE_TYPE (t)))
5596 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5599 /* Add a constraint for a result decl that is passed by reference. */
5600 if (DECL_RESULT (cfun->decl)
5601 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5603 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5605 for (p = result_vi; p; p = p->next)
5606 make_constraint_from (p, nonlocal_id);
5609 /* Add a constraint for the incoming static chain parameter. */
5610 if (cfun->static_chain_decl != NULL_TREE)
5612 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5614 for (p = chain_vi; p; p = p->next)
5615 make_constraint_from (p, nonlocal_id);
5619 /* Structure used to put solution bitmaps in a hashtable so they can
5620 be shared among variables with the same points-to set. */
5622 typedef struct shared_bitmap_info
5626 } *shared_bitmap_info_t;
5627 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5629 static htab_t shared_bitmap_table;
5631 /* Hash function for a shared_bitmap_info_t */
5634 shared_bitmap_hash (const void *p)
5636 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5637 return bi->hashcode;
5640 /* Equality function for two shared_bitmap_info_t's. */
5643 shared_bitmap_eq (const void *p1, const void *p2)
5645 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5646 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5647 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5650 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5651 existing instance if there is one, NULL otherwise. */
5654 shared_bitmap_lookup (bitmap pt_vars)
5657 struct shared_bitmap_info sbi;
5659 sbi.pt_vars = pt_vars;
5660 sbi.hashcode = bitmap_hash (pt_vars);
5662 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5663 sbi.hashcode, NO_INSERT);
5667 return ((shared_bitmap_info_t) *slot)->pt_vars;
5671 /* Add a bitmap to the shared bitmap hashtable. */
5674 shared_bitmap_add (bitmap pt_vars)
5677 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5679 sbi->pt_vars = pt_vars;
5680 sbi->hashcode = bitmap_hash (pt_vars);
5682 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5683 sbi->hashcode, INSERT);
5684 gcc_assert (!*slot);
5685 *slot = (void *) sbi;
5689 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5692 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5697 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5699 varinfo_t vi = get_varinfo (i);
5701 /* The only artificial variables that are allowed in a may-alias
5702 set are heap variables. */
5703 if (vi->is_artificial_var && !vi->is_heap_var)
5706 if (TREE_CODE (vi->decl) == VAR_DECL
5707 || TREE_CODE (vi->decl) == PARM_DECL
5708 || TREE_CODE (vi->decl) == RESULT_DECL)
5710 /* If we are in IPA mode we will not recompute points-to
5711 sets after inlining so make sure they stay valid. */
5713 && !DECL_PT_UID_SET_P (vi->decl))
5714 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5716 /* Add the decl to the points-to set. Note that the points-to
5717 set contains global variables. */
5718 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5719 if (vi->is_global_var)
5720 pt->vars_contains_global = true;
5726 /* Compute the points-to solution *PT for the variable VI. */
5729 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5733 bitmap finished_solution;
5737 memset (pt, 0, sizeof (struct pt_solution));
5739 /* This variable may have been collapsed, let's get the real
5741 vi = get_varinfo (find (orig_vi->id));
5743 /* Translate artificial variables into SSA_NAME_PTR_INFO
5745 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5747 varinfo_t vi = get_varinfo (i);
5749 if (vi->is_artificial_var)
5751 if (vi->id == nothing_id)
5753 else if (vi->id == escaped_id)
5756 pt->ipa_escaped = 1;
5760 else if (vi->id == nonlocal_id)
5762 else if (vi->is_heap_var)
5763 /* We represent heapvars in the points-to set properly. */
5765 else if (vi->id == readonly_id)
5768 else if (vi->id == anything_id
5769 || vi->id == integer_id)
5772 if (vi->is_restrict_var)
5773 pt->vars_contains_restrict = true;
5776 /* Instead of doing extra work, simply do not create
5777 elaborate points-to information for pt_anything pointers. */
5779 && (orig_vi->is_artificial_var
5780 || !pt->vars_contains_restrict))
5783 /* Share the final set of variables when possible. */
5784 finished_solution = BITMAP_GGC_ALLOC ();
5785 stats.points_to_sets_created++;
5787 set_uids_in_ptset (finished_solution, vi->solution, pt);
5788 result = shared_bitmap_lookup (finished_solution);
5791 shared_bitmap_add (finished_solution);
5792 pt->vars = finished_solution;
5797 bitmap_clear (finished_solution);
5801 /* Given a pointer variable P, fill in its points-to set. */
5804 find_what_p_points_to (tree p)
5806 struct ptr_info_def *pi;
5810 /* For parameters, get at the points-to set for the actual parm
5812 if (TREE_CODE (p) == SSA_NAME
5813 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5814 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5815 && SSA_NAME_IS_DEFAULT_DEF (p))
5816 lookup_p = SSA_NAME_VAR (p);
5818 vi = lookup_vi_for_tree (lookup_p);
5822 pi = get_ptr_info (p);
5823 find_what_var_points_to (vi, &pi->pt);
5827 /* Query statistics for points-to solutions. */
5830 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5831 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5832 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5833 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5837 dump_pta_stats (FILE *s)
5839 fprintf (s, "\nPTA query stats:\n");
5840 fprintf (s, " pt_solution_includes: "
5841 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5842 HOST_WIDE_INT_PRINT_DEC" queries\n",
5843 pta_stats.pt_solution_includes_no_alias,
5844 pta_stats.pt_solution_includes_no_alias
5845 + pta_stats.pt_solution_includes_may_alias);
5846 fprintf (s, " pt_solutions_intersect: "
5847 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5848 HOST_WIDE_INT_PRINT_DEC" queries\n",
5849 pta_stats.pt_solutions_intersect_no_alias,
5850 pta_stats.pt_solutions_intersect_no_alias
5851 + pta_stats.pt_solutions_intersect_may_alias);
5855 /* Reset the points-to solution *PT to a conservative default
5856 (point to anything). */
5859 pt_solution_reset (struct pt_solution *pt)
5861 memset (pt, 0, sizeof (struct pt_solution));
5862 pt->anything = true;
5865 /* Set the points-to solution *PT to point only to the variables
5866 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5867 global variables and VARS_CONTAINS_RESTRICT specifies whether
5868 it contains restrict tag variables. */
5871 pt_solution_set (struct pt_solution *pt, bitmap vars,
5872 bool vars_contains_global, bool vars_contains_restrict)
5874 memset (pt, 0, sizeof (struct pt_solution));
5876 pt->vars_contains_global = vars_contains_global;
5877 pt->vars_contains_restrict = vars_contains_restrict;
5880 /* Set the points-to solution *PT to point only to the variable VAR. */
5883 pt_solution_set_var (struct pt_solution *pt, tree var)
5885 memset (pt, 0, sizeof (struct pt_solution));
5886 pt->vars = BITMAP_GGC_ALLOC ();
5887 bitmap_set_bit (pt->vars, DECL_UID (var));
5888 pt->vars_contains_global = is_global_var (var);
5891 /* Computes the union of the points-to solutions *DEST and *SRC and
5892 stores the result in *DEST. This changes the points-to bitmap
5893 of *DEST and thus may not be used if that might be shared.
5894 The points-to bitmap of *SRC and *DEST will not be shared after
5895 this function if they were not before. */
5898 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5900 dest->anything |= src->anything;
5903 pt_solution_reset (dest);
5907 dest->nonlocal |= src->nonlocal;
5908 dest->escaped |= src->escaped;
5909 dest->ipa_escaped |= src->ipa_escaped;
5910 dest->null |= src->null;
5911 dest->vars_contains_global |= src->vars_contains_global;
5912 dest->vars_contains_restrict |= src->vars_contains_restrict;
5917 dest->vars = BITMAP_GGC_ALLOC ();
5918 bitmap_ior_into (dest->vars, src->vars);
5921 /* Return true if the points-to solution *PT is empty. */
5924 pt_solution_empty_p (struct pt_solution *pt)
5931 && !bitmap_empty_p (pt->vars))
5934 /* If the solution includes ESCAPED, check if that is empty. */
5936 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5939 /* If the solution includes ESCAPED, check if that is empty. */
5941 && !pt_solution_empty_p (&ipa_escaped_pt))
5947 /* Return true if the points-to solution *PT includes global memory. */
5950 pt_solution_includes_global (struct pt_solution *pt)
5954 || pt->vars_contains_global)
5958 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5960 if (pt->ipa_escaped)
5961 return pt_solution_includes_global (&ipa_escaped_pt);
5963 /* ??? This predicate is not correct for the IPA-PTA solution
5964 as we do not properly distinguish between unit escape points
5965 and global variables. */
5966 if (cfun->gimple_df->ipa_pta)
5972 /* Return true if the points-to solution *PT includes the variable
5973 declaration DECL. */
5976 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5982 && is_global_var (decl))
5986 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5989 /* If the solution includes ESCAPED, check it. */
5991 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5994 /* If the solution includes ESCAPED, check it. */
5996 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6003 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6005 bool res = pt_solution_includes_1 (pt, decl);
6007 ++pta_stats.pt_solution_includes_may_alias;
6009 ++pta_stats.pt_solution_includes_no_alias;
6013 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6017 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6019 if (pt1->anything || pt2->anything)
6022 /* If either points to unknown global memory and the other points to
6023 any global memory they alias. */
6026 || pt2->vars_contains_global))
6028 && pt1->vars_contains_global))
6031 /* Check the escaped solution if required. */
6032 if ((pt1->escaped || pt2->escaped)
6033 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6035 /* If both point to escaped memory and that solution
6036 is not empty they alias. */
6037 if (pt1->escaped && pt2->escaped)
6040 /* If either points to escaped memory see if the escaped solution
6041 intersects with the other. */
6043 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6045 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6049 /* Check the escaped solution if required.
6050 ??? Do we need to check the local against the IPA escaped sets? */
6051 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6052 && !pt_solution_empty_p (&ipa_escaped_pt))
6054 /* If both point to escaped memory and that solution
6055 is not empty they alias. */
6056 if (pt1->ipa_escaped && pt2->ipa_escaped)
6059 /* If either points to escaped memory see if the escaped solution
6060 intersects with the other. */
6061 if ((pt1->ipa_escaped
6062 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6063 || (pt2->ipa_escaped
6064 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6068 /* Now both pointers alias if their points-to solution intersects. */
6071 && bitmap_intersect_p (pt1->vars, pt2->vars));
6075 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6077 bool res = pt_solutions_intersect_1 (pt1, pt2);
6079 ++pta_stats.pt_solutions_intersect_may_alias;
6081 ++pta_stats.pt_solutions_intersect_no_alias;
6085 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6086 qualified pointers are possibly based on the same pointer. */
6089 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6090 struct pt_solution *pt2)
6092 /* If we deal with points-to solutions of two restrict qualified
6093 pointers solely rely on the pointed-to variable bitmap intersection.
6094 For two pointers that are based on each other the bitmaps will
6096 if (pt1->vars_contains_restrict
6097 && pt2->vars_contains_restrict)
6099 gcc_assert (pt1->vars && pt2->vars);
6100 return bitmap_intersect_p (pt1->vars, pt2->vars);
6107 /* Dump points-to information to OUTFILE. */
6110 dump_sa_points_to_info (FILE *outfile)
6114 fprintf (outfile, "\nPoints-to sets\n\n");
6116 if (dump_flags & TDF_STATS)
6118 fprintf (outfile, "Stats:\n");
6119 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6120 fprintf (outfile, "Non-pointer vars: %d\n",
6121 stats.nonpointer_vars);
6122 fprintf (outfile, "Statically unified vars: %d\n",
6123 stats.unified_vars_static);
6124 fprintf (outfile, "Dynamically unified vars: %d\n",
6125 stats.unified_vars_dynamic);
6126 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6127 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6128 fprintf (outfile, "Number of implicit edges: %d\n",
6129 stats.num_implicit_edges);
6132 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6134 varinfo_t vi = get_varinfo (i);
6135 if (!vi->may_have_pointers)
6137 dump_solution_for_var (outfile, i);
6142 /* Debug points-to information to stderr. */
6145 debug_sa_points_to_info (void)
6147 dump_sa_points_to_info (stderr);
6151 /* Initialize the always-existing constraint variables for NULL
6152 ANYTHING, READONLY, and INTEGER */
6155 init_base_vars (void)
6157 struct constraint_expr lhs, rhs;
6158 varinfo_t var_anything;
6159 varinfo_t var_nothing;
6160 varinfo_t var_readonly;
6161 varinfo_t var_escaped;
6162 varinfo_t var_nonlocal;
6163 varinfo_t var_storedanything;
6164 varinfo_t var_integer;
6166 /* Create the NULL variable, used to represent that a variable points
6168 var_nothing = new_var_info (NULL_TREE, "NULL");
6169 gcc_assert (var_nothing->id == nothing_id);
6170 var_nothing->is_artificial_var = 1;
6171 var_nothing->offset = 0;
6172 var_nothing->size = ~0;
6173 var_nothing->fullsize = ~0;
6174 var_nothing->is_special_var = 1;
6175 var_nothing->may_have_pointers = 0;
6176 var_nothing->is_global_var = 0;
6178 /* Create the ANYTHING variable, used to represent that a variable
6179 points to some unknown piece of memory. */
6180 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6181 gcc_assert (var_anything->id == anything_id);
6182 var_anything->is_artificial_var = 1;
6183 var_anything->size = ~0;
6184 var_anything->offset = 0;
6185 var_anything->next = NULL;
6186 var_anything->fullsize = ~0;
6187 var_anything->is_special_var = 1;
6189 /* Anything points to anything. This makes deref constraints just
6190 work in the presence of linked list and other p = *p type loops,
6191 by saying that *ANYTHING = ANYTHING. */
6193 lhs.var = anything_id;
6195 rhs.type = ADDRESSOF;
6196 rhs.var = anything_id;
6199 /* This specifically does not use process_constraint because
6200 process_constraint ignores all anything = anything constraints, since all
6201 but this one are redundant. */
6202 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6204 /* Create the READONLY variable, used to represent that a variable
6205 points to readonly memory. */
6206 var_readonly = new_var_info (NULL_TREE, "READONLY");
6207 gcc_assert (var_readonly->id == readonly_id);
6208 var_readonly->is_artificial_var = 1;
6209 var_readonly->offset = 0;
6210 var_readonly->size = ~0;
6211 var_readonly->fullsize = ~0;
6212 var_readonly->next = NULL;
6213 var_readonly->is_special_var = 1;
6215 /* readonly memory points to anything, in order to make deref
6216 easier. In reality, it points to anything the particular
6217 readonly variable can point to, but we don't track this
6220 lhs.var = readonly_id;
6222 rhs.type = ADDRESSOF;
6223 rhs.var = readonly_id; /* FIXME */
6225 process_constraint (new_constraint (lhs, rhs));
6227 /* Create the ESCAPED variable, used to represent the set of escaped
6229 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6230 gcc_assert (var_escaped->id == escaped_id);
6231 var_escaped->is_artificial_var = 1;
6232 var_escaped->offset = 0;
6233 var_escaped->size = ~0;
6234 var_escaped->fullsize = ~0;
6235 var_escaped->is_special_var = 0;
6237 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6239 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6240 gcc_assert (var_nonlocal->id == nonlocal_id);
6241 var_nonlocal->is_artificial_var = 1;
6242 var_nonlocal->offset = 0;
6243 var_nonlocal->size = ~0;
6244 var_nonlocal->fullsize = ~0;
6245 var_nonlocal->is_special_var = 1;
6247 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6249 lhs.var = escaped_id;
6252 rhs.var = escaped_id;
6254 process_constraint (new_constraint (lhs, rhs));
6256 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6257 whole variable escapes. */
6259 lhs.var = escaped_id;
6262 rhs.var = escaped_id;
6263 rhs.offset = UNKNOWN_OFFSET;
6264 process_constraint (new_constraint (lhs, rhs));
6266 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6267 everything pointed to by escaped points to what global memory can
6270 lhs.var = escaped_id;
6273 rhs.var = nonlocal_id;
6275 process_constraint (new_constraint (lhs, rhs));
6277 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6278 global memory may point to global memory and escaped memory. */
6280 lhs.var = nonlocal_id;
6282 rhs.type = ADDRESSOF;
6283 rhs.var = nonlocal_id;
6285 process_constraint (new_constraint (lhs, rhs));
6286 rhs.type = ADDRESSOF;
6287 rhs.var = escaped_id;
6289 process_constraint (new_constraint (lhs, rhs));
6291 /* Create the STOREDANYTHING variable, used to represent the set of
6292 variables stored to *ANYTHING. */
6293 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6294 gcc_assert (var_storedanything->id == storedanything_id);
6295 var_storedanything->is_artificial_var = 1;
6296 var_storedanything->offset = 0;
6297 var_storedanything->size = ~0;
6298 var_storedanything->fullsize = ~0;
6299 var_storedanything->is_special_var = 0;
6301 /* Create the INTEGER variable, used to represent that a variable points
6302 to what an INTEGER "points to". */
6303 var_integer = new_var_info (NULL_TREE, "INTEGER");
6304 gcc_assert (var_integer->id == integer_id);
6305 var_integer->is_artificial_var = 1;
6306 var_integer->size = ~0;
6307 var_integer->fullsize = ~0;
6308 var_integer->offset = 0;
6309 var_integer->next = NULL;
6310 var_integer->is_special_var = 1;
6312 /* INTEGER = ANYTHING, because we don't know where a dereference of
6313 a random integer will point to. */
6315 lhs.var = integer_id;
6317 rhs.type = ADDRESSOF;
6318 rhs.var = anything_id;
6320 process_constraint (new_constraint (lhs, rhs));
6323 /* Initialize things necessary to perform PTA */
6326 init_alias_vars (void)
6328 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6330 bitmap_obstack_initialize (&pta_obstack);
6331 bitmap_obstack_initialize (&oldpta_obstack);
6332 bitmap_obstack_initialize (&predbitmap_obstack);
6334 constraint_pool = create_alloc_pool ("Constraint pool",
6335 sizeof (struct constraint), 30);
6336 variable_info_pool = create_alloc_pool ("Variable info pool",
6337 sizeof (struct variable_info), 30);
6338 constraints = VEC_alloc (constraint_t, heap, 8);
6339 varmap = VEC_alloc (varinfo_t, heap, 8);
6340 vi_for_tree = pointer_map_create ();
6341 call_stmt_vars = pointer_map_create ();
6343 memset (&stats, 0, sizeof (stats));
6344 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6345 shared_bitmap_eq, free);
6349 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6350 predecessor edges. */
6353 remove_preds_and_fake_succs (constraint_graph_t graph)
6357 /* Clear the implicit ref and address nodes from the successor
6359 for (i = 0; i < FIRST_REF_NODE; i++)
6361 if (graph->succs[i])
6362 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6363 FIRST_REF_NODE * 2);
6366 /* Free the successor list for the non-ref nodes. */
6367 for (i = FIRST_REF_NODE; i < graph->size; i++)
6369 if (graph->succs[i])
6370 BITMAP_FREE (graph->succs[i]);
6373 /* Now reallocate the size of the successor list as, and blow away
6374 the predecessor bitmaps. */
6375 graph->size = VEC_length (varinfo_t, varmap);
6376 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6378 free (graph->implicit_preds);
6379 graph->implicit_preds = NULL;
6380 free (graph->preds);
6381 graph->preds = NULL;
6382 bitmap_obstack_release (&predbitmap_obstack);
6385 /* Initialize the heapvar for statement mapping. */
6388 init_alias_heapvars (void)
6390 if (!heapvar_for_stmt)
6391 heapvar_for_stmt = htab_create_ggc (11, tree_map_hash, heapvar_map_eq,
6395 /* Delete the heapvar for statement mapping. */
6398 delete_alias_heapvars (void)
6400 if (heapvar_for_stmt)
6401 htab_delete (heapvar_for_stmt);
6402 heapvar_for_stmt = NULL;
6405 /* Solve the constraint set. */
6408 solve_constraints (void)
6410 struct scc_info *si;
6414 "\nCollapsing static cycles and doing variable "
6417 init_graph (VEC_length (varinfo_t, varmap) * 2);
6420 fprintf (dump_file, "Building predecessor graph\n");
6421 build_pred_graph ();
6424 fprintf (dump_file, "Detecting pointer and location "
6426 si = perform_var_substitution (graph);
6429 fprintf (dump_file, "Rewriting constraints and unifying "
6431 rewrite_constraints (graph, si);
6433 build_succ_graph ();
6434 free_var_substitution_info (si);
6436 if (dump_file && (dump_flags & TDF_GRAPH))
6437 dump_constraint_graph (dump_file);
6439 move_complex_constraints (graph);
6442 fprintf (dump_file, "Uniting pointer but not location equivalent "
6444 unite_pointer_equivalences (graph);
6447 fprintf (dump_file, "Finding indirect cycles\n");
6448 find_indirect_cycles (graph);
6450 /* Implicit nodes and predecessors are no longer necessary at this
6452 remove_preds_and_fake_succs (graph);
6455 fprintf (dump_file, "Solving graph\n");
6457 solve_graph (graph);
6460 dump_sa_points_to_info (dump_file);
6463 /* Create points-to sets for the current function. See the comments
6464 at the start of the file for an algorithmic overview. */
6467 compute_points_to_sets (void)
6473 timevar_push (TV_TREE_PTA);
6476 init_alias_heapvars ();
6478 intra_create_variable_infos ();
6480 /* Now walk all statements and build the constraint set. */
6483 gimple_stmt_iterator gsi;
6485 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6487 gimple phi = gsi_stmt (gsi);
6489 if (is_gimple_reg (gimple_phi_result (phi)))
6490 find_func_aliases (phi);
6493 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6495 gimple stmt = gsi_stmt (gsi);
6497 find_func_aliases (stmt);
6503 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6504 dump_constraints (dump_file, 0);
6507 /* From the constraints compute the points-to sets. */
6508 solve_constraints ();
6510 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6511 find_what_var_points_to (get_varinfo (escaped_id),
6512 &cfun->gimple_df->escaped);
6514 /* Make sure the ESCAPED solution (which is used as placeholder in
6515 other solutions) does not reference itself. This simplifies
6516 points-to solution queries. */
6517 cfun->gimple_df->escaped.escaped = 0;
6519 /* Mark escaped HEAP variables as global. */
6520 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6522 && !vi->is_restrict_var
6523 && !vi->is_global_var)
6524 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6525 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6527 /* Compute the points-to sets for pointer SSA_NAMEs. */
6528 for (i = 0; i < num_ssa_names; ++i)
6530 tree ptr = ssa_name (i);
6532 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6533 find_what_p_points_to (ptr);
6536 /* Compute the call-used/clobbered sets. */
6539 gimple_stmt_iterator gsi;
6541 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6543 gimple stmt = gsi_stmt (gsi);
6544 struct pt_solution *pt;
6545 if (!is_gimple_call (stmt))
6548 pt = gimple_call_use_set (stmt);
6549 if (gimple_call_flags (stmt) & ECF_CONST)
6550 memset (pt, 0, sizeof (struct pt_solution));
6551 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6553 find_what_var_points_to (vi, pt);
6554 /* Escaped (and thus nonlocal) variables are always
6555 implicitly used by calls. */
6556 /* ??? ESCAPED can be empty even though NONLOCAL
6563 /* If there is nothing special about this call then
6564 we have made everything that is used also escape. */
6565 *pt = cfun->gimple_df->escaped;
6569 pt = gimple_call_clobber_set (stmt);
6570 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6571 memset (pt, 0, sizeof (struct pt_solution));
6572 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6574 find_what_var_points_to (vi, pt);
6575 /* Escaped (and thus nonlocal) variables are always
6576 implicitly clobbered by calls. */
6577 /* ??? ESCAPED can be empty even though NONLOCAL
6584 /* If there is nothing special about this call then
6585 we have made everything that is used also escape. */
6586 *pt = cfun->gimple_df->escaped;
6592 timevar_pop (TV_TREE_PTA);
6596 /* Delete created points-to sets. */
6599 delete_points_to_sets (void)
6603 htab_delete (shared_bitmap_table);
6604 if (dump_file && (dump_flags & TDF_STATS))
6605 fprintf (dump_file, "Points to sets created:%d\n",
6606 stats.points_to_sets_created);
6608 pointer_map_destroy (vi_for_tree);
6609 pointer_map_destroy (call_stmt_vars);
6610 bitmap_obstack_release (&pta_obstack);
6611 VEC_free (constraint_t, heap, constraints);
6613 for (i = 0; i < graph->size; i++)
6614 VEC_free (constraint_t, heap, graph->complex[i]);
6615 free (graph->complex);
6618 free (graph->succs);
6620 free (graph->pe_rep);
6621 free (graph->indirect_cycles);
6624 VEC_free (varinfo_t, heap, varmap);
6625 free_alloc_pool (variable_info_pool);
6626 free_alloc_pool (constraint_pool);
6630 /* Compute points-to information for every SSA_NAME pointer in the
6631 current function and compute the transitive closure of escaped
6632 variables to re-initialize the call-clobber states of local variables. */
6635 compute_may_aliases (void)
6637 if (cfun->gimple_df->ipa_pta)
6641 fprintf (dump_file, "\nNot re-computing points-to information "
6642 "because IPA points-to information is available.\n\n");
6644 /* But still dump what we have remaining it. */
6645 dump_alias_info (dump_file);
6647 if (dump_flags & TDF_DETAILS)
6648 dump_referenced_vars (dump_file);
6654 /* For each pointer P_i, determine the sets of variables that P_i may
6655 point-to. Compute the reachability set of escaped and call-used
6657 compute_points_to_sets ();
6659 /* Debugging dumps. */
6662 dump_alias_info (dump_file);
6664 if (dump_flags & TDF_DETAILS)
6665 dump_referenced_vars (dump_file);
6668 /* Deallocate memory used by aliasing data structures and the internal
6669 points-to solution. */
6670 delete_points_to_sets ();
6672 gcc_assert (!need_ssa_update_p (cfun));
6678 gate_tree_pta (void)
6680 return flag_tree_pta;
6683 /* A dummy pass to cause points-to information to be computed via
6684 TODO_rebuild_alias. */
6686 struct gimple_opt_pass pass_build_alias =
6691 gate_tree_pta, /* gate */
6695 0, /* static_pass_number */
6696 TV_NONE, /* tv_id */
6697 PROP_cfg | PROP_ssa, /* properties_required */
6698 0, /* properties_provided */
6699 0, /* properties_destroyed */
6700 0, /* todo_flags_start */
6701 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6705 /* A dummy pass to cause points-to information to be computed via
6706 TODO_rebuild_alias. */
6708 struct gimple_opt_pass pass_build_ealias =
6712 "ealias", /* name */
6713 gate_tree_pta, /* gate */
6717 0, /* static_pass_number */
6718 TV_NONE, /* tv_id */
6719 PROP_cfg | PROP_ssa, /* properties_required */
6720 0, /* properties_provided */
6721 0, /* properties_destroyed */
6722 0, /* todo_flags_start */
6723 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6728 /* Return true if we should execute IPA PTA. */
6734 /* Don't bother doing anything if the program has errors. */
6738 /* IPA PTA solutions for ESCAPED. */
6739 struct pt_solution ipa_escaped_pt
6740 = { true, false, false, false, false, false, false, NULL };
6742 /* Execute the driver for IPA PTA. */
6744 ipa_pta_execute (void)
6746 struct cgraph_node *node;
6747 struct varpool_node *var;
6752 init_alias_heapvars ();
6755 /* Build the constraints. */
6756 for (node = cgraph_nodes; node; node = node->next)
6758 struct cgraph_node *alias;
6761 /* Nodes without a body are not interesting. Especially do not
6762 visit clones at this point for now - we get duplicate decls
6763 there for inline clones at least. */
6764 if (!gimple_has_body_p (node->decl)
6768 vi = create_function_info_for (node->decl,
6769 alias_get_name (node->decl));
6771 /* Associate the varinfo node with all aliases. */
6772 for (alias = node->same_body; alias; alias = alias->next)
6773 insert_vi_for_tree (alias->decl, vi);
6776 /* Create constraints for global variables and their initializers. */
6777 for (var = varpool_nodes; var; var = var->next)
6779 struct varpool_node *alias;
6782 vi = get_vi_for_tree (var->decl);
6784 /* Associate the varinfo node with all aliases. */
6785 for (alias = var->extra_name; alias; alias = alias->next)
6786 insert_vi_for_tree (alias->decl, vi);
6792 "Generating constraints for global initializers\n\n");
6793 dump_constraints (dump_file, 0);
6794 fprintf (dump_file, "\n");
6796 from = VEC_length (constraint_t, constraints);
6798 for (node = cgraph_nodes; node; node = node->next)
6800 struct function *func;
6804 /* Nodes without a body are not interesting. */
6805 if (!gimple_has_body_p (node->decl)
6812 "Generating constraints for %s", cgraph_node_name (node));
6813 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6814 fprintf (dump_file, " (%s)",
6815 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6816 fprintf (dump_file, "\n");
6819 func = DECL_STRUCT_FUNCTION (node->decl);
6820 old_func_decl = current_function_decl;
6822 current_function_decl = node->decl;
6824 /* For externally visible functions use local constraints for
6825 their arguments. For local functions we see all callers
6826 and thus do not need initial constraints for parameters. */
6827 if (node->local.externally_visible)
6828 intra_create_variable_infos ();
6830 /* Build constriants for the function body. */
6831 FOR_EACH_BB_FN (bb, func)
6833 gimple_stmt_iterator gsi;
6835 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6838 gimple phi = gsi_stmt (gsi);
6840 if (is_gimple_reg (gimple_phi_result (phi)))
6841 find_func_aliases (phi);
6844 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6846 gimple stmt = gsi_stmt (gsi);
6848 find_func_aliases (stmt);
6849 find_func_clobbers (stmt);
6853 current_function_decl = old_func_decl;
6858 fprintf (dump_file, "\n");
6859 dump_constraints (dump_file, from);
6860 fprintf (dump_file, "\n");
6862 from = VEC_length (constraint_t, constraints);
6865 /* From the constraints compute the points-to sets. */
6866 solve_constraints ();
6868 /* Compute the global points-to sets for ESCAPED.
6869 ??? Note that the computed escape set is not correct
6870 for the whole unit as we fail to consider graph edges to
6871 externally visible functions. */
6872 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6874 /* Make sure the ESCAPED solution (which is used as placeholder in
6875 other solutions) does not reference itself. This simplifies
6876 points-to solution queries. */
6877 ipa_escaped_pt.ipa_escaped = 0;
6879 /* Assign the points-to sets to the SSA names in the unit. */
6880 for (node = cgraph_nodes; node; node = node->next)
6883 struct function *fn;
6887 struct pt_solution uses, clobbers;
6888 struct cgraph_edge *e;
6890 /* Nodes without a body are not interesting. */
6891 if (!gimple_has_body_p (node->decl)
6895 fn = DECL_STRUCT_FUNCTION (node->decl);
6897 /* Compute the points-to sets for pointer SSA_NAMEs. */
6898 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6901 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6902 find_what_p_points_to (ptr);
6905 /* Compute the call-use and call-clobber sets for all direct calls. */
6906 fi = lookup_vi_for_tree (node->decl);
6907 gcc_assert (fi->is_fn_info);
6908 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6910 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6911 for (e = node->callers; e; e = e->next_caller)
6916 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6917 *gimple_call_use_set (e->call_stmt) = uses;
6920 /* Compute the call-use and call-clobber sets for indirect calls
6921 and calls to external functions. */
6922 FOR_EACH_BB_FN (bb, fn)
6924 gimple_stmt_iterator gsi;
6926 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6928 gimple stmt = gsi_stmt (gsi);
6929 struct pt_solution *pt;
6933 if (!is_gimple_call (stmt))
6936 /* Handle direct calls to external functions. */
6937 decl = gimple_call_fndecl (stmt);
6939 && (!(fi = lookup_vi_for_tree (decl))
6940 || !fi->is_fn_info))
6942 pt = gimple_call_use_set (stmt);
6943 if (gimple_call_flags (stmt) & ECF_CONST)
6944 memset (pt, 0, sizeof (struct pt_solution));
6945 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6947 find_what_var_points_to (vi, pt);
6948 /* Escaped (and thus nonlocal) variables are always
6949 implicitly used by calls. */
6950 /* ??? ESCAPED can be empty even though NONLOCAL
6953 pt->ipa_escaped = 1;
6957 /* If there is nothing special about this call then
6958 we have made everything that is used also escape. */
6959 *pt = ipa_escaped_pt;
6963 pt = gimple_call_clobber_set (stmt);
6964 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6965 memset (pt, 0, sizeof (struct pt_solution));
6966 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6968 find_what_var_points_to (vi, pt);
6969 /* Escaped (and thus nonlocal) variables are always
6970 implicitly clobbered by calls. */
6971 /* ??? ESCAPED can be empty even though NONLOCAL
6974 pt->ipa_escaped = 1;
6978 /* If there is nothing special about this call then
6979 we have made everything that is used also escape. */
6980 *pt = ipa_escaped_pt;
6985 /* Handle indirect calls. */
6987 && (fi = get_fi_for_callee (stmt)))
6989 /* We need to accumulate all clobbers/uses of all possible
6991 fi = get_varinfo (find (fi->id));
6992 /* If we cannot constrain the set of functions we'll end up
6993 calling we end up using/clobbering everything. */
6994 if (bitmap_bit_p (fi->solution, anything_id)
6995 || bitmap_bit_p (fi->solution, nonlocal_id)
6996 || bitmap_bit_p (fi->solution, escaped_id))
6998 pt_solution_reset (gimple_call_clobber_set (stmt));
6999 pt_solution_reset (gimple_call_use_set (stmt));
7005 struct pt_solution *uses, *clobbers;
7007 uses = gimple_call_use_set (stmt);
7008 clobbers = gimple_call_clobber_set (stmt);
7009 memset (uses, 0, sizeof (struct pt_solution));
7010 memset (clobbers, 0, sizeof (struct pt_solution));
7011 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7013 struct pt_solution sol;
7015 vi = get_varinfo (i);
7016 if (!vi->is_fn_info)
7018 /* ??? We could be more precise here? */
7020 uses->ipa_escaped = 1;
7021 clobbers->nonlocal = 1;
7022 clobbers->ipa_escaped = 1;
7026 if (!uses->anything)
7028 find_what_var_points_to
7029 (first_vi_for_offset (vi, fi_uses), &sol);
7030 pt_solution_ior_into (uses, &sol);
7032 if (!clobbers->anything)
7034 find_what_var_points_to
7035 (first_vi_for_offset (vi, fi_clobbers), &sol);
7036 pt_solution_ior_into (clobbers, &sol);
7044 fn->gimple_df->ipa_pta = true;
7047 delete_points_to_sets ();
7054 struct simple_ipa_opt_pass pass_ipa_pta =
7059 gate_ipa_pta, /* gate */
7060 ipa_pta_execute, /* execute */
7063 0, /* static_pass_number */
7064 TV_IPA_PTA, /* tv_id */
7065 0, /* properties_required */
7066 0, /* properties_provided */
7067 0, /* properties_destroyed */
7068 0, /* todo_flags_start */
7069 TODO_update_ssa /* todo_flags_finish */
7074 #include "gt-tree-ssa-structalias.h"