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"
40 #include "tree-pass.h"
42 #include "alloc-pool.h"
43 #include "splay-tree.h"
47 #include "pointer-set.h"
49 /* The idea behind this analyzer is to generate set constraints from the
50 program, then solve the resulting constraints in order to generate the
53 Set constraints are a way of modeling program analysis problems that
54 involve sets. They consist of an inclusion constraint language,
55 describing the variables (each variable is a set) and operations that
56 are involved on the variables, and a set of rules that derive facts
57 from these operations. To solve a system of set constraints, you derive
58 all possible facts under the rules, which gives you the correct sets
61 See "Efficient Field-sensitive pointer analysis for C" by "David
62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
63 http://citeseer.ist.psu.edu/pearce04efficient.html
65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
67 http://citeseer.ist.psu.edu/heintze01ultrafast.html
69 There are three types of real constraint expressions, DEREF,
70 ADDRESSOF, and SCALAR. Each constraint expression consists
71 of a constraint type, a variable, and an offset.
73 SCALAR is a constraint expression type used to represent x, whether
74 it appears on the LHS or the RHS of a statement.
75 DEREF is a constraint expression type used to represent *x, whether
76 it appears on the LHS or the RHS of a statement.
77 ADDRESSOF is a constraint expression used to represent &x, whether
78 it appears on the LHS or the RHS of a statement.
80 Each pointer variable in the program is assigned an integer id, and
81 each field of a structure variable is assigned an integer id as well.
83 Structure variables are linked to their list of fields through a "next
84 field" in each variable that points to the next field in offset
86 Each variable for a structure field has
88 1. "size", that tells the size in bits of that field.
89 2. "fullsize, that tells the size in bits of the entire structure.
90 3. "offset", that tells the offset in bits from the beginning of the
91 structure to this field.
103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
108 In order to solve the system of set constraints, the following is
111 1. Each constraint variable x has a solution set associated with it,
114 2. Constraints are separated into direct, copy, and complex.
115 Direct constraints are ADDRESSOF constraints that require no extra
116 processing, such as P = &Q
117 Copy constraints are those of the form P = Q.
118 Complex constraints are all the constraints involving dereferences
119 and offsets (including offsetted copies).
121 3. All direct constraints of the form P = &Q are processed, such
122 that Q is added to Sol(P)
124 4. All complex constraints for a given constraint variable are stored in a
125 linked list attached to that variable's node.
127 5. A directed graph is built out of the copy constraints. Each
128 constraint variable is a node in the graph, and an edge from
129 Q to P is added for each copy constraint of the form P = Q
131 6. The graph is then walked, and solution sets are
132 propagated along the copy edges, such that an edge from Q to P
133 causes Sol(P) <- Sol(P) union Sol(Q).
135 7. As we visit each node, all complex constraints associated with
136 that node are processed by adding appropriate copy edges to the graph, or the
137 appropriate variables to the solution set.
139 8. The process of walking the graph is iterated until no solution
142 Prior to walking the graph in steps 6 and 7, We perform static
143 cycle elimination on the constraint graph, as well
144 as off-line variable substitution.
146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
147 on and turned into anything), but isn't. You can just see what offset
148 inside the pointed-to struct it's going to access.
150 TODO: Constant bounded arrays can be handled as if they were structs of the
151 same number of elements.
153 TODO: Modeling heap and incoming pointers becomes much better if we
154 add fields to them as we discover them, which we could do.
156 TODO: We could handle unions, but to be honest, it's probably not
157 worth the pain or slowdown. */
159 /* IPA-PTA optimizations possible.
161 When the indirect function called is ANYTHING we can add disambiguation
162 based on the function signatures (or simply the parameter count which
163 is the varinfo size). We also do not need to consider functions that
164 do not have their address taken.
166 The is_global_var bit which marks escape points is overly conservative
167 in IPA mode. Split it to is_escape_point and is_global_var - only
168 externally visible globals are escape points in IPA mode. This is
169 also needed to fix the pt_solution_includes_global predicate
170 (and thus ptr_deref_may_alias_global_p).
172 The way we introduce DECL_PT_UID to avoid fixing up all points-to
173 sets in the translation unit when we copy a DECL during inlining
174 pessimizes precision. The advantage is that the DECL_PT_UID keeps
175 compile-time and memory usage overhead low - the points-to sets
176 do not grow or get unshared as they would during a fixup phase.
177 An alternative solution is to delay IPA PTA until after all
178 inlining transformations have been applied.
180 The way we propagate clobber/use information isn't optimized.
181 It should use a new complex constraint that properly filters
182 out local variables of the callee (though that would make
183 the sets invalid after inlining). OTOH we might as well
184 admit defeat to WHOPR and simply do all the clobber/use analysis
185 and propagation after PTA finished but before we threw away
186 points-to information for memory variables. WHOPR and PTA
187 do not play along well anyway - the whole constraint solving
188 would need to be done in WPA phase and it will be very interesting
189 to apply the results to local SSA names during LTRANS phase.
191 We probably should compute a per-function unit-ESCAPE solution
192 propagating it simply like the clobber / uses solutions. The
193 solution can go alongside the non-IPA espaced solution and be
194 used to query which vars escape the unit through a function.
196 We never put function decls in points-to sets so we do not
197 keep the set of called functions for indirect calls.
199 And probably more. */
201 static bool use_field_sensitive = true;
202 static int in_ipa_mode = 0;
204 /* Used for predecessor bitmaps. */
205 static bitmap_obstack predbitmap_obstack;
207 /* Used for points-to sets. */
208 static bitmap_obstack pta_obstack;
210 /* Used for oldsolution members of variables. */
211 static bitmap_obstack oldpta_obstack;
213 /* Used for per-solver-iteration bitmaps. */
214 static bitmap_obstack iteration_obstack;
216 static unsigned int create_variable_info_for (tree, const char *);
217 typedef struct constraint_graph *constraint_graph_t;
218 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
221 typedef struct constraint *constraint_t;
223 DEF_VEC_P(constraint_t);
224 DEF_VEC_ALLOC_P(constraint_t,heap);
226 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
228 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
230 static struct constraint_stats
232 unsigned int total_vars;
233 unsigned int nonpointer_vars;
234 unsigned int unified_vars_static;
235 unsigned int unified_vars_dynamic;
236 unsigned int iterations;
237 unsigned int num_edges;
238 unsigned int num_implicit_edges;
239 unsigned int points_to_sets_created;
244 /* ID of this variable */
247 /* True if this is a variable created by the constraint analysis, such as
248 heap variables and constraints we had to break up. */
249 unsigned int is_artificial_var : 1;
251 /* True if this is a special variable whose solution set should not be
253 unsigned int is_special_var : 1;
255 /* True for variables whose size is not known or variable. */
256 unsigned int is_unknown_size_var : 1;
258 /* True for (sub-)fields that represent a whole variable. */
259 unsigned int is_full_var : 1;
261 /* True if this is a heap variable. */
262 unsigned int is_heap_var : 1;
264 /* True if this is a variable tracking a restrict pointer source. */
265 unsigned int is_restrict_var : 1;
267 /* True if this field may contain pointers. */
268 unsigned int may_have_pointers : 1;
270 /* True if this field has only restrict qualified pointers. */
271 unsigned int only_restrict_pointers : 1;
273 /* True if this represents a global variable. */
274 unsigned int is_global_var : 1;
276 /* True if this represents a IPA function info. */
277 unsigned int is_fn_info : 1;
279 /* A link to the variable for the next field in this structure. */
280 struct variable_info *next;
282 /* Offset of this variable, in bits, from the base variable */
283 unsigned HOST_WIDE_INT offset;
285 /* Size of the variable, in bits. */
286 unsigned HOST_WIDE_INT size;
288 /* Full size of the base variable, in bits. */
289 unsigned HOST_WIDE_INT fullsize;
291 /* Name of this variable */
294 /* Tree that this variable is associated with. */
297 /* Points-to set for this variable. */
300 /* Old points-to set for this variable. */
303 typedef struct variable_info *varinfo_t;
305 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
306 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
307 unsigned HOST_WIDE_INT);
308 static varinfo_t lookup_vi_for_tree (tree);
310 /* Pool of variable info structures. */
311 static alloc_pool variable_info_pool;
313 DEF_VEC_P(varinfo_t);
315 DEF_VEC_ALLOC_P(varinfo_t, heap);
317 /* Table of variable info structures for constraint variables.
318 Indexed directly by variable info id. */
319 static VEC(varinfo_t,heap) *varmap;
321 /* Return the varmap element N */
323 static inline varinfo_t
324 get_varinfo (unsigned int n)
326 return VEC_index (varinfo_t, varmap, n);
329 /* Static IDs for the special variables. */
330 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
331 escaped_id = 3, nonlocal_id = 4,
332 storedanything_id = 5, integer_id = 6 };
334 /* Return a new variable info structure consisting for a variable
335 named NAME, and using constraint graph node NODE. Append it
336 to the vector of variable info structures. */
339 new_var_info (tree t, const char *name)
341 unsigned index = VEC_length (varinfo_t, varmap);
342 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
347 /* Vars without decl are artificial and do not have sub-variables. */
348 ret->is_artificial_var = (t == NULL_TREE);
349 ret->is_special_var = false;
350 ret->is_unknown_size_var = false;
351 ret->is_full_var = (t == NULL_TREE);
352 ret->is_heap_var = false;
353 ret->is_restrict_var = false;
354 ret->may_have_pointers = true;
355 ret->only_restrict_pointers = false;
356 ret->is_global_var = (t == NULL_TREE);
357 ret->is_fn_info = false;
359 ret->is_global_var = (is_global_var (t)
360 /* We have to treat even local register variables
362 || (TREE_CODE (t) == VAR_DECL
363 && DECL_HARD_REGISTER (t)));
364 ret->solution = BITMAP_ALLOC (&pta_obstack);
365 ret->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
370 VEC_safe_push (varinfo_t, heap, varmap, ret);
376 /* A map mapping call statements to per-stmt variables for uses
377 and clobbers specific to the call. */
378 struct pointer_map_t *call_stmt_vars;
380 /* Lookup or create the variable for the call statement CALL. */
383 get_call_vi (gimple call)
388 slot_p = pointer_map_insert (call_stmt_vars, call);
390 return (varinfo_t) *slot_p;
392 vi = new_var_info (NULL_TREE, "CALLUSED");
396 vi->is_full_var = true;
398 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
402 vi2->is_full_var = true;
404 *slot_p = (void *) vi;
408 /* Lookup the variable for the call statement CALL representing
409 the uses. Returns NULL if there is nothing special about this call. */
412 lookup_call_use_vi (gimple call)
416 slot_p = pointer_map_contains (call_stmt_vars, call);
418 return (varinfo_t) *slot_p;
423 /* Lookup the variable for the call statement CALL representing
424 the clobbers. Returns NULL if there is nothing special about this call. */
427 lookup_call_clobber_vi (gimple call)
429 varinfo_t uses = lookup_call_use_vi (call);
436 /* Lookup or create the variable for the call statement CALL representing
440 get_call_use_vi (gimple call)
442 return get_call_vi (call);
445 /* Lookup or create the variable for the call statement CALL representing
448 static varinfo_t ATTRIBUTE_UNUSED
449 get_call_clobber_vi (gimple call)
451 return get_call_vi (call)->next;
455 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
457 /* An expression that appears in a constraint. */
459 struct constraint_expr
461 /* Constraint type. */
462 constraint_expr_type type;
464 /* Variable we are referring to in the constraint. */
467 /* Offset, in bits, of this constraint from the beginning of
468 variables it ends up referring to.
470 IOW, in a deref constraint, we would deref, get the result set,
471 then add OFFSET to each member. */
472 HOST_WIDE_INT offset;
475 /* Use 0x8000... as special unknown offset. */
476 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
478 typedef struct constraint_expr ce_s;
480 DEF_VEC_ALLOC_O(ce_s, heap);
481 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
482 static void get_constraint_for (tree, VEC(ce_s, heap) **);
483 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
484 static void do_deref (VEC (ce_s, heap) **);
486 /* Our set constraints are made up of two constraint expressions, one
489 As described in the introduction, our set constraints each represent an
490 operation between set valued variables.
494 struct constraint_expr lhs;
495 struct constraint_expr rhs;
498 /* List of constraints that we use to build the constraint graph from. */
500 static VEC(constraint_t,heap) *constraints;
501 static alloc_pool constraint_pool;
503 /* The constraint graph is represented as an array of bitmaps
504 containing successor nodes. */
506 struct constraint_graph
508 /* Size of this graph, which may be different than the number of
509 nodes in the variable map. */
512 /* Explicit successors of each node. */
515 /* Implicit predecessors of each node (Used for variable
517 bitmap *implicit_preds;
519 /* Explicit predecessors of each node (Used for variable substitution). */
522 /* Indirect cycle representatives, or -1 if the node has no indirect
524 int *indirect_cycles;
526 /* Representative node for a node. rep[a] == a unless the node has
530 /* Equivalence class representative for a label. This is used for
531 variable substitution. */
534 /* Pointer equivalence label for a node. All nodes with the same
535 pointer equivalence label can be unified together at some point
536 (either during constraint optimization or after the constraint
540 /* Pointer equivalence representative for a label. This is used to
541 handle nodes that are pointer equivalent but not location
542 equivalent. We can unite these once the addressof constraints
543 are transformed into initial points-to sets. */
546 /* Pointer equivalence label for each node, used during variable
548 unsigned int *pointer_label;
550 /* Location equivalence label for each node, used during location
551 equivalence finding. */
552 unsigned int *loc_label;
554 /* Pointed-by set for each node, used during location equivalence
555 finding. This is pointed-by rather than pointed-to, because it
556 is constructed using the predecessor graph. */
559 /* Points to sets for pointer equivalence. This is *not* the actual
560 points-to sets for nodes. */
563 /* Bitmap of nodes where the bit is set if the node is a direct
564 node. Used for variable substitution. */
565 sbitmap direct_nodes;
567 /* Bitmap of nodes where the bit is set if the node is address
568 taken. Used for variable substitution. */
569 bitmap address_taken;
571 /* Vector of complex constraints for each graph node. Complex
572 constraints are those involving dereferences or offsets that are
574 VEC(constraint_t,heap) **complex;
577 static constraint_graph_t graph;
579 /* During variable substitution and the offline version of indirect
580 cycle finding, we create nodes to represent dereferences and
581 address taken constraints. These represent where these start and
583 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
584 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
586 /* Return the representative node for NODE, if NODE has been unioned
588 This function performs path compression along the way to finding
589 the representative. */
592 find (unsigned int node)
594 gcc_assert (node < graph->size);
595 if (graph->rep[node] != node)
596 return graph->rep[node] = find (graph->rep[node]);
600 /* Union the TO and FROM nodes to the TO nodes.
601 Note that at some point in the future, we may want to do
602 union-by-rank, in which case we are going to have to return the
603 node we unified to. */
606 unite (unsigned int to, unsigned int from)
608 gcc_assert (to < graph->size && from < graph->size);
609 if (to != from && graph->rep[from] != to)
611 graph->rep[from] = to;
617 /* Create a new constraint consisting of LHS and RHS expressions. */
620 new_constraint (const struct constraint_expr lhs,
621 const struct constraint_expr rhs)
623 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
629 /* Print out constraint C to FILE. */
632 dump_constraint (FILE *file, constraint_t c)
634 if (c->lhs.type == ADDRESSOF)
636 else if (c->lhs.type == DEREF)
638 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
639 if (c->lhs.offset == UNKNOWN_OFFSET)
640 fprintf (file, " + UNKNOWN");
641 else if (c->lhs.offset != 0)
642 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
643 fprintf (file, " = ");
644 if (c->rhs.type == ADDRESSOF)
646 else if (c->rhs.type == DEREF)
648 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
649 if (c->rhs.offset == UNKNOWN_OFFSET)
650 fprintf (file, " + UNKNOWN");
651 else if (c->rhs.offset != 0)
652 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
653 fprintf (file, "\n");
657 void debug_constraint (constraint_t);
658 void debug_constraints (void);
659 void debug_constraint_graph (void);
660 void debug_solution_for_var (unsigned int);
661 void debug_sa_points_to_info (void);
663 /* Print out constraint C to stderr. */
666 debug_constraint (constraint_t c)
668 dump_constraint (stderr, c);
671 /* Print out all constraints to FILE */
674 dump_constraints (FILE *file, int from)
678 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
679 dump_constraint (file, c);
682 /* Print out all constraints to stderr. */
685 debug_constraints (void)
687 dump_constraints (stderr, 0);
690 /* Print out to FILE the edge in the constraint graph that is created by
691 constraint c. The edge may have a label, depending on the type of
692 constraint that it represents. If complex1, e.g: a = *b, then the label
693 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
694 complex with an offset, e.g: a = b + 8, then the label is "+".
695 Otherwise the edge has no label. */
698 dump_constraint_edge (FILE *file, constraint_t c)
700 if (c->rhs.type != ADDRESSOF)
702 const char *src = get_varinfo (c->rhs.var)->name;
703 const char *dst = get_varinfo (c->lhs.var)->name;
704 fprintf (file, " \"%s\" -> \"%s\" ", src, dst);
705 /* Due to preprocessing of constraints, instructions like *a = *b are
706 illegal; thus, we do not have to handle such cases. */
707 if (c->lhs.type == DEREF)
708 fprintf (file, " [ label=\"*=\" ] ;\n");
709 else if (c->rhs.type == DEREF)
710 fprintf (file, " [ label=\"=*\" ] ;\n");
713 /* We must check the case where the constraint is an offset.
714 In this case, it is treated as a complex constraint. */
715 if (c->rhs.offset != c->lhs.offset)
716 fprintf (file, " [ label=\"+\" ] ;\n");
718 fprintf (file, " ;\n");
723 /* Print the constraint graph in dot format. */
726 dump_constraint_graph (FILE *file)
728 unsigned int i=0, size;
731 /* Only print the graph if it has already been initialized: */
735 /* Print the constraints used to produce the constraint graph. The
736 constraints will be printed as comments in the dot file: */
737 fprintf (file, "\n\n/* Constraints used in the constraint graph:\n");
738 dump_constraints (file, 0);
739 fprintf (file, "*/\n");
741 /* Prints the header of the dot file: */
742 fprintf (file, "\n\n// The constraint graph in dot format:\n");
743 fprintf (file, "strict digraph {\n");
744 fprintf (file, " node [\n shape = box\n ]\n");
745 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
746 fprintf (file, "\n // List of nodes in the constraint graph:\n");
748 /* The next lines print the nodes in the graph. In order to get the
749 number of nodes in the graph, we must choose the minimum between the
750 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
751 yet been initialized, then graph->size == 0, otherwise we must only
752 read nodes that have an entry in VEC (varinfo_t, varmap). */
753 size = VEC_length (varinfo_t, varmap);
754 size = size < graph->size ? size : graph->size;
755 for (i = 0; i < size; i++)
757 const char *name = get_varinfo (graph->rep[i])->name;
758 fprintf (file, " \"%s\" ;\n", name);
761 /* Go over the list of constraints printing the edges in the constraint
763 fprintf (file, "\n // The constraint edges:\n");
764 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
766 dump_constraint_edge (file, c);
768 /* Prints the tail of the dot file. By now, only the closing bracket. */
769 fprintf (file, "}\n\n\n");
772 /* Print out the constraint graph to stderr. */
775 debug_constraint_graph (void)
777 dump_constraint_graph (stderr);
782 The solver is a simple worklist solver, that works on the following
785 sbitmap changed_nodes = all zeroes;
787 For each node that is not already collapsed:
789 set bit in changed nodes
791 while (changed_count > 0)
793 compute topological ordering for constraint graph
795 find and collapse cycles in the constraint graph (updating
796 changed if necessary)
798 for each node (n) in the graph in topological order:
801 Process each complex constraint associated with the node,
802 updating changed if necessary.
804 For each outgoing edge from n, propagate the solution from n to
805 the destination of the edge, updating changed as necessary.
809 /* Return true if two constraint expressions A and B are equal. */
812 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
814 return a.type == b.type && a.var == b.var && a.offset == b.offset;
817 /* Return true if constraint expression A is less than constraint expression
818 B. This is just arbitrary, but consistent, in order to give them an
822 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
824 if (a.type == b.type)
827 return a.offset < b.offset;
829 return a.var < b.var;
832 return a.type < b.type;
835 /* Return true if constraint A is less than constraint B. This is just
836 arbitrary, but consistent, in order to give them an ordering. */
839 constraint_less (const constraint_t a, const constraint_t b)
841 if (constraint_expr_less (a->lhs, b->lhs))
843 else if (constraint_expr_less (b->lhs, a->lhs))
846 return constraint_expr_less (a->rhs, b->rhs);
849 /* Return true if two constraints A and B are equal. */
852 constraint_equal (struct constraint a, struct constraint b)
854 return constraint_expr_equal (a.lhs, b.lhs)
855 && constraint_expr_equal (a.rhs, b.rhs);
859 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
862 constraint_vec_find (VEC(constraint_t,heap) *vec,
863 struct constraint lookfor)
871 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
872 if (place >= VEC_length (constraint_t, vec))
874 found = VEC_index (constraint_t, vec, place);
875 if (!constraint_equal (*found, lookfor))
880 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
883 constraint_set_union (VEC(constraint_t,heap) **to,
884 VEC(constraint_t,heap) **from)
889 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
891 if (constraint_vec_find (*to, *c) == NULL)
893 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
895 VEC_safe_insert (constraint_t, heap, *to, place, c);
900 /* Expands the solution in SET to all sub-fields of variables included.
901 Union the expanded result into RESULT. */
904 solution_set_expand (bitmap result, bitmap set)
910 /* In a first pass record all variables we need to add all
911 sub-fields off. This avoids quadratic behavior. */
912 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
914 varinfo_t v = get_varinfo (j);
915 if (v->is_artificial_var
918 v = lookup_vi_for_tree (v->decl);
920 vars = BITMAP_ALLOC (NULL);
921 bitmap_set_bit (vars, v->id);
924 /* In the second pass now do the addition to the solution and
925 to speed up solving add it to the delta as well. */
928 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
930 varinfo_t v = get_varinfo (j);
931 for (; v != NULL; v = v->next)
932 bitmap_set_bit (result, v->id);
938 /* Take a solution set SET, add OFFSET to each member of the set, and
939 overwrite SET with the result when done. */
942 solution_set_add (bitmap set, HOST_WIDE_INT offset)
944 bitmap result = BITMAP_ALLOC (&iteration_obstack);
948 /* If the offset is unknown we have to expand the solution to
950 if (offset == UNKNOWN_OFFSET)
952 solution_set_expand (set, set);
956 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
958 varinfo_t vi = get_varinfo (i);
960 /* If this is a variable with just one field just set its bit
962 if (vi->is_artificial_var
963 || vi->is_unknown_size_var
965 bitmap_set_bit (result, i);
968 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
970 /* If the offset makes the pointer point to before the
971 variable use offset zero for the field lookup. */
973 && fieldoffset > vi->offset)
977 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
979 bitmap_set_bit (result, vi->id);
980 /* If the result is not exactly at fieldoffset include the next
981 field as well. See get_constraint_for_ptr_offset for more
983 if (vi->offset != fieldoffset
985 bitmap_set_bit (result, vi->next->id);
989 bitmap_copy (set, result);
990 BITMAP_FREE (result);
993 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
997 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
1000 return bitmap_ior_into (to, from);
1006 tmp = BITMAP_ALLOC (&iteration_obstack);
1007 bitmap_copy (tmp, from);
1008 solution_set_add (tmp, inc);
1009 res = bitmap_ior_into (to, tmp);
1015 /* Insert constraint C into the list of complex constraints for graph
1019 insert_into_complex (constraint_graph_t graph,
1020 unsigned int var, constraint_t c)
1022 VEC (constraint_t, heap) *complex = graph->complex[var];
1023 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1026 /* Only insert constraints that do not already exist. */
1027 if (place >= VEC_length (constraint_t, complex)
1028 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1029 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1033 /* Condense two variable nodes into a single variable node, by moving
1034 all associated info from SRC to TO. */
1037 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1043 gcc_assert (find (from) == to);
1045 /* Move all complex constraints from src node into to node */
1046 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1048 /* In complex constraints for node src, we may have either
1049 a = *src, and *src = a, or an offseted constraint which are
1050 always added to the rhs node's constraints. */
1052 if (c->rhs.type == DEREF)
1054 else if (c->lhs.type == DEREF)
1059 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1060 VEC_free (constraint_t, heap, graph->complex[from]);
1061 graph->complex[from] = NULL;
1065 /* Remove edges involving NODE from GRAPH. */
1068 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1070 if (graph->succs[node])
1071 BITMAP_FREE (graph->succs[node]);
1074 /* Merge GRAPH nodes FROM and TO into node TO. */
1077 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1080 if (graph->indirect_cycles[from] != -1)
1082 /* If we have indirect cycles with the from node, and we have
1083 none on the to node, the to node has indirect cycles from the
1084 from node now that they are unified.
1085 If indirect cycles exist on both, unify the nodes that they
1086 are in a cycle with, since we know they are in a cycle with
1088 if (graph->indirect_cycles[to] == -1)
1089 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1092 /* Merge all the successor edges. */
1093 if (graph->succs[from])
1095 if (!graph->succs[to])
1096 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1097 bitmap_ior_into (graph->succs[to],
1098 graph->succs[from]);
1101 clear_edges_for_node (graph, from);
1105 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1106 it doesn't exist in the graph already. */
1109 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1115 if (!graph->implicit_preds[to])
1116 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1118 if (bitmap_set_bit (graph->implicit_preds[to], from))
1119 stats.num_implicit_edges++;
1122 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1123 it doesn't exist in the graph already.
1124 Return false if the edge already existed, true otherwise. */
1127 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1130 if (!graph->preds[to])
1131 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1132 bitmap_set_bit (graph->preds[to], from);
1135 /* Add a graph edge to GRAPH, going from FROM to TO if
1136 it doesn't exist in the graph already.
1137 Return false if the edge already existed, true otherwise. */
1140 add_graph_edge (constraint_graph_t graph, unsigned int to,
1151 if (!graph->succs[from])
1152 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1153 if (bitmap_set_bit (graph->succs[from], to))
1156 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1164 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1167 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1170 return (graph->succs[dest]
1171 && bitmap_bit_p (graph->succs[dest], src));
1174 /* Initialize the constraint graph structure to contain SIZE nodes. */
1177 init_graph (unsigned int size)
1181 graph = XCNEW (struct constraint_graph);
1183 graph->succs = XCNEWVEC (bitmap, graph->size);
1184 graph->indirect_cycles = XNEWVEC (int, graph->size);
1185 graph->rep = XNEWVEC (unsigned int, graph->size);
1186 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1187 graph->pe = XCNEWVEC (unsigned int, graph->size);
1188 graph->pe_rep = XNEWVEC (int, graph->size);
1190 for (j = 0; j < graph->size; j++)
1193 graph->pe_rep[j] = -1;
1194 graph->indirect_cycles[j] = -1;
1198 /* Build the constraint graph, adding only predecessor edges right now. */
1201 build_pred_graph (void)
1207 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1208 graph->preds = XCNEWVEC (bitmap, graph->size);
1209 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1210 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1211 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1212 graph->points_to = XCNEWVEC (bitmap, graph->size);
1213 graph->eq_rep = XNEWVEC (int, graph->size);
1214 graph->direct_nodes = sbitmap_alloc (graph->size);
1215 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1216 sbitmap_zero (graph->direct_nodes);
1218 for (j = 0; j < FIRST_REF_NODE; j++)
1220 if (!get_varinfo (j)->is_special_var)
1221 SET_BIT (graph->direct_nodes, j);
1224 for (j = 0; j < graph->size; j++)
1225 graph->eq_rep[j] = -1;
1227 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1228 graph->indirect_cycles[j] = -1;
1230 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1232 struct constraint_expr lhs = c->lhs;
1233 struct constraint_expr rhs = c->rhs;
1234 unsigned int lhsvar = lhs.var;
1235 unsigned int rhsvar = rhs.var;
1237 if (lhs.type == DEREF)
1240 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1241 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1243 else if (rhs.type == DEREF)
1246 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1247 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1249 RESET_BIT (graph->direct_nodes, lhsvar);
1251 else if (rhs.type == ADDRESSOF)
1256 if (graph->points_to[lhsvar] == NULL)
1257 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1258 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1260 if (graph->pointed_by[rhsvar] == NULL)
1261 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1262 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1264 /* Implicitly, *x = y */
1265 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1267 /* All related variables are no longer direct nodes. */
1268 RESET_BIT (graph->direct_nodes, rhsvar);
1269 v = get_varinfo (rhsvar);
1270 if (!v->is_full_var)
1272 v = lookup_vi_for_tree (v->decl);
1275 RESET_BIT (graph->direct_nodes, v->id);
1280 bitmap_set_bit (graph->address_taken, rhsvar);
1282 else if (lhsvar > anything_id
1283 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1286 add_pred_graph_edge (graph, lhsvar, rhsvar);
1287 /* Implicitly, *x = *y */
1288 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1289 FIRST_REF_NODE + rhsvar);
1291 else if (lhs.offset != 0 || rhs.offset != 0)
1293 if (rhs.offset != 0)
1294 RESET_BIT (graph->direct_nodes, lhs.var);
1295 else if (lhs.offset != 0)
1296 RESET_BIT (graph->direct_nodes, rhs.var);
1301 /* Build the constraint graph, adding successor edges. */
1304 build_succ_graph (void)
1309 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1311 struct constraint_expr lhs;
1312 struct constraint_expr rhs;
1313 unsigned int lhsvar;
1314 unsigned int rhsvar;
1321 lhsvar = find (lhs.var);
1322 rhsvar = find (rhs.var);
1324 if (lhs.type == DEREF)
1326 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1327 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1329 else if (rhs.type == DEREF)
1331 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1332 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1334 else if (rhs.type == ADDRESSOF)
1337 gcc_assert (find (rhs.var) == rhs.var);
1338 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1340 else if (lhsvar > anything_id
1341 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1343 add_graph_edge (graph, lhsvar, rhsvar);
1347 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1348 receive pointers. */
1349 t = find (storedanything_id);
1350 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1352 if (!TEST_BIT (graph->direct_nodes, i)
1353 && get_varinfo (i)->may_have_pointers)
1354 add_graph_edge (graph, find (i), t);
1357 /* Everything stored to ANYTHING also potentially escapes. */
1358 add_graph_edge (graph, find (escaped_id), t);
1362 /* Changed variables on the last iteration. */
1363 static bitmap changed;
1365 /* Strongly Connected Component visitation info. */
1372 unsigned int *node_mapping;
1374 VEC(unsigned,heap) *scc_stack;
1378 /* Recursive routine to find strongly connected components in GRAPH.
1379 SI is the SCC info to store the information in, and N is the id of current
1380 graph node we are processing.
1382 This is Tarjan's strongly connected component finding algorithm, as
1383 modified by Nuutila to keep only non-root nodes on the stack.
1384 The algorithm can be found in "On finding the strongly connected
1385 connected components in a directed graph" by Esko Nuutila and Eljas
1386 Soisalon-Soininen, in Information Processing Letters volume 49,
1387 number 1, pages 9-14. */
1390 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1394 unsigned int my_dfs;
1396 SET_BIT (si->visited, n);
1397 si->dfs[n] = si->current_index ++;
1398 my_dfs = si->dfs[n];
1400 /* Visit all the successors. */
1401 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1405 if (i > LAST_REF_NODE)
1409 if (TEST_BIT (si->deleted, w))
1412 if (!TEST_BIT (si->visited, w))
1413 scc_visit (graph, si, w);
1415 unsigned int t = find (w);
1416 unsigned int nnode = find (n);
1417 gcc_assert (nnode == n);
1419 if (si->dfs[t] < si->dfs[nnode])
1420 si->dfs[n] = si->dfs[t];
1424 /* See if any components have been identified. */
1425 if (si->dfs[n] == my_dfs)
1427 if (VEC_length (unsigned, si->scc_stack) > 0
1428 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1430 bitmap scc = BITMAP_ALLOC (NULL);
1431 unsigned int lowest_node;
1434 bitmap_set_bit (scc, n);
1436 while (VEC_length (unsigned, si->scc_stack) != 0
1437 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1439 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1441 bitmap_set_bit (scc, w);
1444 lowest_node = bitmap_first_set_bit (scc);
1445 gcc_assert (lowest_node < FIRST_REF_NODE);
1447 /* Collapse the SCC nodes into a single node, and mark the
1449 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1451 if (i < FIRST_REF_NODE)
1453 if (unite (lowest_node, i))
1454 unify_nodes (graph, lowest_node, i, false);
1458 unite (lowest_node, i);
1459 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1463 SET_BIT (si->deleted, n);
1466 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1469 /* Unify node FROM into node TO, updating the changed count if
1470 necessary when UPDATE_CHANGED is true. */
1473 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1474 bool update_changed)
1477 gcc_assert (to != from && find (to) == to);
1478 if (dump_file && (dump_flags & TDF_DETAILS))
1479 fprintf (dump_file, "Unifying %s to %s\n",
1480 get_varinfo (from)->name,
1481 get_varinfo (to)->name);
1484 stats.unified_vars_dynamic++;
1486 stats.unified_vars_static++;
1488 merge_graph_nodes (graph, to, from);
1489 merge_node_constraints (graph, to, from);
1491 /* Mark TO as changed if FROM was changed. If TO was already marked
1492 as changed, decrease the changed count. */
1495 && bitmap_bit_p (changed, from))
1497 bitmap_clear_bit (changed, from);
1498 bitmap_set_bit (changed, to);
1500 if (get_varinfo (from)->solution)
1502 /* If the solution changes because of the merging, we need to mark
1503 the variable as changed. */
1504 if (bitmap_ior_into (get_varinfo (to)->solution,
1505 get_varinfo (from)->solution))
1508 bitmap_set_bit (changed, to);
1511 BITMAP_FREE (get_varinfo (from)->solution);
1512 BITMAP_FREE (get_varinfo (from)->oldsolution);
1514 if (stats.iterations > 0)
1516 BITMAP_FREE (get_varinfo (to)->oldsolution);
1517 get_varinfo (to)->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
1520 if (valid_graph_edge (graph, to, to))
1522 if (graph->succs[to])
1523 bitmap_clear_bit (graph->succs[to], to);
1527 /* Information needed to compute the topological ordering of a graph. */
1531 /* sbitmap of visited nodes. */
1533 /* Array that stores the topological order of the graph, *in
1535 VEC(unsigned,heap) *topo_order;
1539 /* Initialize and return a topological info structure. */
1541 static struct topo_info *
1542 init_topo_info (void)
1544 size_t size = graph->size;
1545 struct topo_info *ti = XNEW (struct topo_info);
1546 ti->visited = sbitmap_alloc (size);
1547 sbitmap_zero (ti->visited);
1548 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1553 /* Free the topological sort info pointed to by TI. */
1556 free_topo_info (struct topo_info *ti)
1558 sbitmap_free (ti->visited);
1559 VEC_free (unsigned, heap, ti->topo_order);
1563 /* Visit the graph in topological order, and store the order in the
1564 topo_info structure. */
1567 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1573 SET_BIT (ti->visited, n);
1575 if (graph->succs[n])
1576 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1578 if (!TEST_BIT (ti->visited, j))
1579 topo_visit (graph, ti, j);
1582 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1585 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1586 starting solution for y. */
1589 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1592 unsigned int lhs = c->lhs.var;
1594 bitmap sol = get_varinfo (lhs)->solution;
1597 HOST_WIDE_INT roffset = c->rhs.offset;
1599 /* Our IL does not allow this. */
1600 gcc_assert (c->lhs.offset == 0);
1602 /* If the solution of Y contains anything it is good enough to transfer
1604 if (bitmap_bit_p (delta, anything_id))
1606 flag |= bitmap_set_bit (sol, anything_id);
1610 /* If we do not know at with offset the rhs is dereferenced compute
1611 the reachability set of DELTA, conservatively assuming it is
1612 dereferenced at all valid offsets. */
1613 if (roffset == UNKNOWN_OFFSET)
1615 solution_set_expand (delta, delta);
1616 /* No further offset processing is necessary. */
1620 /* For each variable j in delta (Sol(y)), add
1621 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1622 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1624 varinfo_t v = get_varinfo (j);
1625 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1629 fieldoffset = v->offset;
1630 else if (roffset != 0)
1631 v = first_vi_for_offset (v, fieldoffset);
1632 /* If the access is outside of the variable we can ignore it. */
1640 /* Adding edges from the special vars is pointless.
1641 They don't have sets that can change. */
1642 if (get_varinfo (t)->is_special_var)
1643 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1644 /* Merging the solution from ESCAPED needlessly increases
1645 the set. Use ESCAPED as representative instead. */
1646 else if (v->id == escaped_id)
1647 flag |= bitmap_set_bit (sol, escaped_id);
1648 else if (v->may_have_pointers
1649 && add_graph_edge (graph, lhs, t))
1650 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1652 /* If the variable is not exactly at the requested offset
1653 we have to include the next one. */
1654 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1659 fieldoffset = v->offset;
1665 /* If the LHS solution changed, mark the var as changed. */
1668 get_varinfo (lhs)->solution = sol;
1669 bitmap_set_bit (changed, lhs);
1673 /* Process a constraint C that represents *(x + off) = y using DELTA
1674 as the starting solution for x. */
1677 do_ds_constraint (constraint_t c, bitmap delta)
1679 unsigned int rhs = c->rhs.var;
1680 bitmap sol = get_varinfo (rhs)->solution;
1683 HOST_WIDE_INT loff = c->lhs.offset;
1684 bool escaped_p = false;
1686 /* Our IL does not allow this. */
1687 gcc_assert (c->rhs.offset == 0);
1689 /* If the solution of y contains ANYTHING simply use the ANYTHING
1690 solution. This avoids needlessly increasing the points-to sets. */
1691 if (bitmap_bit_p (sol, anything_id))
1692 sol = get_varinfo (find (anything_id))->solution;
1694 /* If the solution for x contains ANYTHING we have to merge the
1695 solution of y into all pointer variables which we do via
1697 if (bitmap_bit_p (delta, anything_id))
1699 unsigned t = find (storedanything_id);
1700 if (add_graph_edge (graph, t, rhs))
1702 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1703 bitmap_set_bit (changed, t);
1708 /* If we do not know at with offset the rhs is dereferenced compute
1709 the reachability set of DELTA, conservatively assuming it is
1710 dereferenced at all valid offsets. */
1711 if (loff == UNKNOWN_OFFSET)
1713 solution_set_expand (delta, delta);
1717 /* For each member j of delta (Sol(x)), add an edge from y to j and
1718 union Sol(y) into Sol(j) */
1719 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1721 varinfo_t v = get_varinfo (j);
1723 HOST_WIDE_INT fieldoffset = v->offset + loff;
1726 fieldoffset = v->offset;
1728 v = first_vi_for_offset (v, fieldoffset);
1729 /* If the access is outside of the variable we can ignore it. */
1735 if (v->may_have_pointers)
1737 /* If v is a global variable then this is an escape point. */
1738 if (v->is_global_var
1741 t = find (escaped_id);
1742 if (add_graph_edge (graph, t, rhs)
1743 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1744 bitmap_set_bit (changed, t);
1745 /* Enough to let rhs escape once. */
1749 if (v->is_special_var)
1753 if (add_graph_edge (graph, t, rhs)
1754 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1755 bitmap_set_bit (changed, t);
1758 /* If the variable is not exactly at the requested offset
1759 we have to include the next one. */
1760 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1765 fieldoffset = v->offset;
1771 /* Handle a non-simple (simple meaning requires no iteration),
1772 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1775 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1777 if (c->lhs.type == DEREF)
1779 if (c->rhs.type == ADDRESSOF)
1786 do_ds_constraint (c, delta);
1789 else if (c->rhs.type == DEREF)
1792 if (!(get_varinfo (c->lhs.var)->is_special_var))
1793 do_sd_constraint (graph, c, delta);
1801 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1802 solution = get_varinfo (c->rhs.var)->solution;
1803 tmp = get_varinfo (c->lhs.var)->solution;
1805 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1809 get_varinfo (c->lhs.var)->solution = tmp;
1810 bitmap_set_bit (changed, c->lhs.var);
1815 /* Initialize and return a new SCC info structure. */
1817 static struct scc_info *
1818 init_scc_info (size_t size)
1820 struct scc_info *si = XNEW (struct scc_info);
1823 si->current_index = 0;
1824 si->visited = sbitmap_alloc (size);
1825 sbitmap_zero (si->visited);
1826 si->deleted = sbitmap_alloc (size);
1827 sbitmap_zero (si->deleted);
1828 si->node_mapping = XNEWVEC (unsigned int, size);
1829 si->dfs = XCNEWVEC (unsigned int, size);
1831 for (i = 0; i < size; i++)
1832 si->node_mapping[i] = i;
1834 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1838 /* Free an SCC info structure pointed to by SI */
1841 free_scc_info (struct scc_info *si)
1843 sbitmap_free (si->visited);
1844 sbitmap_free (si->deleted);
1845 free (si->node_mapping);
1847 VEC_free (unsigned, heap, si->scc_stack);
1852 /* Find indirect cycles in GRAPH that occur, using strongly connected
1853 components, and note them in the indirect cycles map.
1855 This technique comes from Ben Hardekopf and Calvin Lin,
1856 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1857 Lines of Code", submitted to PLDI 2007. */
1860 find_indirect_cycles (constraint_graph_t graph)
1863 unsigned int size = graph->size;
1864 struct scc_info *si = init_scc_info (size);
1866 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1867 if (!TEST_BIT (si->visited, i) && find (i) == i)
1868 scc_visit (graph, si, i);
1873 /* Compute a topological ordering for GRAPH, and store the result in the
1874 topo_info structure TI. */
1877 compute_topo_order (constraint_graph_t graph,
1878 struct topo_info *ti)
1881 unsigned int size = graph->size;
1883 for (i = 0; i != size; ++i)
1884 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1885 topo_visit (graph, ti, i);
1888 /* Structure used to for hash value numbering of pointer equivalence
1891 typedef struct equiv_class_label
1894 unsigned int equivalence_class;
1896 } *equiv_class_label_t;
1897 typedef const struct equiv_class_label *const_equiv_class_label_t;
1899 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1901 static htab_t pointer_equiv_class_table;
1903 /* A hashtable for mapping a bitmap of labels->location equivalence
1905 static htab_t location_equiv_class_table;
1907 /* Hash function for a equiv_class_label_t */
1910 equiv_class_label_hash (const void *p)
1912 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1913 return ecl->hashcode;
1916 /* Equality function for two equiv_class_label_t's. */
1919 equiv_class_label_eq (const void *p1, const void *p2)
1921 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1922 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1923 return (eql1->hashcode == eql2->hashcode
1924 && bitmap_equal_p (eql1->labels, eql2->labels));
1927 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1931 equiv_class_lookup (htab_t table, bitmap labels)
1934 struct equiv_class_label ecl;
1936 ecl.labels = labels;
1937 ecl.hashcode = bitmap_hash (labels);
1939 slot = htab_find_slot_with_hash (table, &ecl,
1940 ecl.hashcode, NO_INSERT);
1944 return ((equiv_class_label_t) *slot)->equivalence_class;
1948 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1952 equiv_class_add (htab_t table, unsigned int equivalence_class,
1956 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1958 ecl->labels = labels;
1959 ecl->equivalence_class = equivalence_class;
1960 ecl->hashcode = bitmap_hash (labels);
1962 slot = htab_find_slot_with_hash (table, ecl,
1963 ecl->hashcode, INSERT);
1964 gcc_assert (!*slot);
1965 *slot = (void *) ecl;
1968 /* Perform offline variable substitution.
1970 This is a worst case quadratic time way of identifying variables
1971 that must have equivalent points-to sets, including those caused by
1972 static cycles, and single entry subgraphs, in the constraint graph.
1974 The technique is described in "Exploiting Pointer and Location
1975 Equivalence to Optimize Pointer Analysis. In the 14th International
1976 Static Analysis Symposium (SAS), August 2007." It is known as the
1977 "HU" algorithm, and is equivalent to value numbering the collapsed
1978 constraint graph including evaluating unions.
1980 The general method of finding equivalence classes is as follows:
1981 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1982 Initialize all non-REF nodes to be direct nodes.
1983 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1985 For each constraint containing the dereference, we also do the same
1988 We then compute SCC's in the graph and unify nodes in the same SCC,
1991 For each non-collapsed node x:
1992 Visit all unvisited explicit incoming edges.
1993 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1995 Lookup the equivalence class for pts(x).
1996 If we found one, equivalence_class(x) = found class.
1997 Otherwise, equivalence_class(x) = new class, and new_class is
1998 added to the lookup table.
2000 All direct nodes with the same equivalence class can be replaced
2001 with a single representative node.
2002 All unlabeled nodes (label == 0) are not pointers and all edges
2003 involving them can be eliminated.
2004 We perform these optimizations during rewrite_constraints
2006 In addition to pointer equivalence class finding, we also perform
2007 location equivalence class finding. This is the set of variables
2008 that always appear together in points-to sets. We use this to
2009 compress the size of the points-to sets. */
2011 /* Current maximum pointer equivalence class id. */
2012 static int pointer_equiv_class;
2014 /* Current maximum location equivalence class id. */
2015 static int location_equiv_class;
2017 /* Recursive routine to find strongly connected components in GRAPH,
2018 and label it's nodes with DFS numbers. */
2021 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2025 unsigned int my_dfs;
2027 gcc_assert (si->node_mapping[n] == n);
2028 SET_BIT (si->visited, n);
2029 si->dfs[n] = si->current_index ++;
2030 my_dfs = si->dfs[n];
2032 /* Visit all the successors. */
2033 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2035 unsigned int w = si->node_mapping[i];
2037 if (TEST_BIT (si->deleted, w))
2040 if (!TEST_BIT (si->visited, w))
2041 condense_visit (graph, si, w);
2043 unsigned int t = si->node_mapping[w];
2044 unsigned int nnode = si->node_mapping[n];
2045 gcc_assert (nnode == n);
2047 if (si->dfs[t] < si->dfs[nnode])
2048 si->dfs[n] = si->dfs[t];
2052 /* Visit all the implicit predecessors. */
2053 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2055 unsigned int w = si->node_mapping[i];
2057 if (TEST_BIT (si->deleted, w))
2060 if (!TEST_BIT (si->visited, w))
2061 condense_visit (graph, si, w);
2063 unsigned int t = si->node_mapping[w];
2064 unsigned int nnode = si->node_mapping[n];
2065 gcc_assert (nnode == n);
2067 if (si->dfs[t] < si->dfs[nnode])
2068 si->dfs[n] = si->dfs[t];
2072 /* See if any components have been identified. */
2073 if (si->dfs[n] == my_dfs)
2075 while (VEC_length (unsigned, si->scc_stack) != 0
2076 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2078 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2079 si->node_mapping[w] = n;
2081 if (!TEST_BIT (graph->direct_nodes, w))
2082 RESET_BIT (graph->direct_nodes, n);
2084 /* Unify our nodes. */
2085 if (graph->preds[w])
2087 if (!graph->preds[n])
2088 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2089 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2091 if (graph->implicit_preds[w])
2093 if (!graph->implicit_preds[n])
2094 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2095 bitmap_ior_into (graph->implicit_preds[n],
2096 graph->implicit_preds[w]);
2098 if (graph->points_to[w])
2100 if (!graph->points_to[n])
2101 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2102 bitmap_ior_into (graph->points_to[n],
2103 graph->points_to[w]);
2106 SET_BIT (si->deleted, n);
2109 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2112 /* Label pointer equivalences. */
2115 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2119 SET_BIT (si->visited, n);
2121 if (!graph->points_to[n])
2122 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2124 /* Label and union our incoming edges's points to sets. */
2125 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2127 unsigned int w = si->node_mapping[i];
2128 if (!TEST_BIT (si->visited, w))
2129 label_visit (graph, si, w);
2131 /* Skip unused edges */
2132 if (w == n || graph->pointer_label[w] == 0)
2135 if (graph->points_to[w])
2136 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2138 /* Indirect nodes get fresh variables. */
2139 if (!TEST_BIT (graph->direct_nodes, n))
2140 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2142 if (!bitmap_empty_p (graph->points_to[n]))
2144 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2145 graph->points_to[n]);
2148 label = pointer_equiv_class++;
2149 equiv_class_add (pointer_equiv_class_table,
2150 label, graph->points_to[n]);
2152 graph->pointer_label[n] = label;
2156 /* Perform offline variable substitution, discovering equivalence
2157 classes, and eliminating non-pointer variables. */
2159 static struct scc_info *
2160 perform_var_substitution (constraint_graph_t graph)
2163 unsigned int size = graph->size;
2164 struct scc_info *si = init_scc_info (size);
2166 bitmap_obstack_initialize (&iteration_obstack);
2167 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2168 equiv_class_label_eq, free);
2169 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2170 equiv_class_label_eq, free);
2171 pointer_equiv_class = 1;
2172 location_equiv_class = 1;
2174 /* Condense the nodes, which means to find SCC's, count incoming
2175 predecessors, and unite nodes in SCC's. */
2176 for (i = 0; i < FIRST_REF_NODE; i++)
2177 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2178 condense_visit (graph, si, si->node_mapping[i]);
2180 sbitmap_zero (si->visited);
2181 /* Actually the label the nodes for pointer equivalences */
2182 for (i = 0; i < FIRST_REF_NODE; i++)
2183 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2184 label_visit (graph, si, si->node_mapping[i]);
2186 /* Calculate location equivalence labels. */
2187 for (i = 0; i < FIRST_REF_NODE; i++)
2194 if (!graph->pointed_by[i])
2196 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2198 /* Translate the pointed-by mapping for pointer equivalence
2200 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2202 bitmap_set_bit (pointed_by,
2203 graph->pointer_label[si->node_mapping[j]]);
2205 /* The original pointed_by is now dead. */
2206 BITMAP_FREE (graph->pointed_by[i]);
2208 /* Look up the location equivalence label if one exists, or make
2210 label = equiv_class_lookup (location_equiv_class_table,
2214 label = location_equiv_class++;
2215 equiv_class_add (location_equiv_class_table,
2220 if (dump_file && (dump_flags & TDF_DETAILS))
2221 fprintf (dump_file, "Found location equivalence for node %s\n",
2222 get_varinfo (i)->name);
2223 BITMAP_FREE (pointed_by);
2225 graph->loc_label[i] = label;
2229 if (dump_file && (dump_flags & TDF_DETAILS))
2230 for (i = 0; i < FIRST_REF_NODE; i++)
2232 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2234 "Equivalence classes for %s node id %d:%s are pointer: %d"
2236 direct_node ? "Direct node" : "Indirect node", i,
2237 get_varinfo (i)->name,
2238 graph->pointer_label[si->node_mapping[i]],
2239 graph->loc_label[si->node_mapping[i]]);
2242 /* Quickly eliminate our non-pointer variables. */
2244 for (i = 0; i < FIRST_REF_NODE; i++)
2246 unsigned int node = si->node_mapping[i];
2248 if (graph->pointer_label[node] == 0)
2250 if (dump_file && (dump_flags & TDF_DETAILS))
2252 "%s is a non-pointer variable, eliminating edges.\n",
2253 get_varinfo (node)->name);
2254 stats.nonpointer_vars++;
2255 clear_edges_for_node (graph, node);
2262 /* Free information that was only necessary for variable
2266 free_var_substitution_info (struct scc_info *si)
2269 free (graph->pointer_label);
2270 free (graph->loc_label);
2271 free (graph->pointed_by);
2272 free (graph->points_to);
2273 free (graph->eq_rep);
2274 sbitmap_free (graph->direct_nodes);
2275 htab_delete (pointer_equiv_class_table);
2276 htab_delete (location_equiv_class_table);
2277 bitmap_obstack_release (&iteration_obstack);
2280 /* Return an existing node that is equivalent to NODE, which has
2281 equivalence class LABEL, if one exists. Return NODE otherwise. */
2284 find_equivalent_node (constraint_graph_t graph,
2285 unsigned int node, unsigned int label)
2287 /* If the address version of this variable is unused, we can
2288 substitute it for anything else with the same label.
2289 Otherwise, we know the pointers are equivalent, but not the
2290 locations, and we can unite them later. */
2292 if (!bitmap_bit_p (graph->address_taken, node))
2294 gcc_assert (label < graph->size);
2296 if (graph->eq_rep[label] != -1)
2298 /* Unify the two variables since we know they are equivalent. */
2299 if (unite (graph->eq_rep[label], node))
2300 unify_nodes (graph, graph->eq_rep[label], node, false);
2301 return graph->eq_rep[label];
2305 graph->eq_rep[label] = node;
2306 graph->pe_rep[label] = node;
2311 gcc_assert (label < graph->size);
2312 graph->pe[node] = label;
2313 if (graph->pe_rep[label] == -1)
2314 graph->pe_rep[label] = node;
2320 /* Unite pointer equivalent but not location equivalent nodes in
2321 GRAPH. This may only be performed once variable substitution is
2325 unite_pointer_equivalences (constraint_graph_t graph)
2329 /* Go through the pointer equivalences and unite them to their
2330 representative, if they aren't already. */
2331 for (i = 0; i < FIRST_REF_NODE; i++)
2333 unsigned int label = graph->pe[i];
2336 int label_rep = graph->pe_rep[label];
2338 if (label_rep == -1)
2341 label_rep = find (label_rep);
2342 if (label_rep >= 0 && unite (label_rep, find (i)))
2343 unify_nodes (graph, label_rep, i, false);
2348 /* Move complex constraints to the GRAPH nodes they belong to. */
2351 move_complex_constraints (constraint_graph_t graph)
2356 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2360 struct constraint_expr lhs = c->lhs;
2361 struct constraint_expr rhs = c->rhs;
2363 if (lhs.type == DEREF)
2365 insert_into_complex (graph, lhs.var, c);
2367 else if (rhs.type == DEREF)
2369 if (!(get_varinfo (lhs.var)->is_special_var))
2370 insert_into_complex (graph, rhs.var, c);
2372 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2373 && (lhs.offset != 0 || rhs.offset != 0))
2375 insert_into_complex (graph, rhs.var, c);
2382 /* Optimize and rewrite complex constraints while performing
2383 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2384 result of perform_variable_substitution. */
2387 rewrite_constraints (constraint_graph_t graph,
2388 struct scc_info *si)
2394 for (j = 0; j < graph->size; j++)
2395 gcc_assert (find (j) == j);
2397 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2399 struct constraint_expr lhs = c->lhs;
2400 struct constraint_expr rhs = c->rhs;
2401 unsigned int lhsvar = find (lhs.var);
2402 unsigned int rhsvar = find (rhs.var);
2403 unsigned int lhsnode, rhsnode;
2404 unsigned int lhslabel, rhslabel;
2406 lhsnode = si->node_mapping[lhsvar];
2407 rhsnode = si->node_mapping[rhsvar];
2408 lhslabel = graph->pointer_label[lhsnode];
2409 rhslabel = graph->pointer_label[rhsnode];
2411 /* See if it is really a non-pointer variable, and if so, ignore
2415 if (dump_file && (dump_flags & TDF_DETAILS))
2418 fprintf (dump_file, "%s is a non-pointer variable,"
2419 "ignoring constraint:",
2420 get_varinfo (lhs.var)->name);
2421 dump_constraint (dump_file, c);
2423 VEC_replace (constraint_t, constraints, i, NULL);
2429 if (dump_file && (dump_flags & TDF_DETAILS))
2432 fprintf (dump_file, "%s is a non-pointer variable,"
2433 "ignoring constraint:",
2434 get_varinfo (rhs.var)->name);
2435 dump_constraint (dump_file, c);
2437 VEC_replace (constraint_t, constraints, i, NULL);
2441 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2442 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2443 c->lhs.var = lhsvar;
2444 c->rhs.var = rhsvar;
2449 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2450 part of an SCC, false otherwise. */
2453 eliminate_indirect_cycles (unsigned int node)
2455 if (graph->indirect_cycles[node] != -1
2456 && !bitmap_empty_p (get_varinfo (node)->solution))
2459 VEC(unsigned,heap) *queue = NULL;
2461 unsigned int to = find (graph->indirect_cycles[node]);
2464 /* We can't touch the solution set and call unify_nodes
2465 at the same time, because unify_nodes is going to do
2466 bitmap unions into it. */
2468 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2470 if (find (i) == i && i != to)
2473 VEC_safe_push (unsigned, heap, queue, i);
2478 VEC_iterate (unsigned, queue, queuepos, i);
2481 unify_nodes (graph, to, i, true);
2483 VEC_free (unsigned, heap, queue);
2489 /* Solve the constraint graph GRAPH using our worklist solver.
2490 This is based on the PW* family of solvers from the "Efficient Field
2491 Sensitive Pointer Analysis for C" paper.
2492 It works by iterating over all the graph nodes, processing the complex
2493 constraints and propagating the copy constraints, until everything stops
2494 changed. This corresponds to steps 6-8 in the solving list given above. */
2497 solve_graph (constraint_graph_t graph)
2499 unsigned int size = graph->size;
2503 changed = BITMAP_ALLOC (NULL);
2505 /* Mark all initial non-collapsed nodes as changed. */
2506 for (i = 0; i < size; i++)
2508 varinfo_t ivi = get_varinfo (i);
2509 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2510 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2511 || VEC_length (constraint_t, graph->complex[i]) > 0))
2512 bitmap_set_bit (changed, i);
2515 /* Allocate a bitmap to be used to store the changed bits. */
2516 pts = BITMAP_ALLOC (&pta_obstack);
2518 while (!bitmap_empty_p (changed))
2521 struct topo_info *ti = init_topo_info ();
2524 bitmap_obstack_initialize (&iteration_obstack);
2526 compute_topo_order (graph, ti);
2528 while (VEC_length (unsigned, ti->topo_order) != 0)
2531 i = VEC_pop (unsigned, ti->topo_order);
2533 /* If this variable is not a representative, skip it. */
2537 /* In certain indirect cycle cases, we may merge this
2538 variable to another. */
2539 if (eliminate_indirect_cycles (i) && find (i) != i)
2542 /* If the node has changed, we need to process the
2543 complex constraints and outgoing edges again. */
2544 if (bitmap_clear_bit (changed, i))
2549 VEC(constraint_t,heap) *complex = graph->complex[i];
2550 bool solution_empty;
2552 /* Compute the changed set of solution bits. */
2553 bitmap_and_compl (pts, get_varinfo (i)->solution,
2554 get_varinfo (i)->oldsolution);
2556 if (bitmap_empty_p (pts))
2559 bitmap_ior_into (get_varinfo (i)->oldsolution, pts);
2561 solution = get_varinfo (i)->solution;
2562 solution_empty = bitmap_empty_p (solution);
2564 /* Process the complex constraints */
2565 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2567 /* XXX: This is going to unsort the constraints in
2568 some cases, which will occasionally add duplicate
2569 constraints during unification. This does not
2570 affect correctness. */
2571 c->lhs.var = find (c->lhs.var);
2572 c->rhs.var = find (c->rhs.var);
2574 /* The only complex constraint that can change our
2575 solution to non-empty, given an empty solution,
2576 is a constraint where the lhs side is receiving
2577 some set from elsewhere. */
2578 if (!solution_empty || c->lhs.type != DEREF)
2579 do_complex_constraint (graph, c, pts);
2582 solution_empty = bitmap_empty_p (solution);
2584 if (!solution_empty)
2587 unsigned eff_escaped_id = find (escaped_id);
2589 /* Propagate solution to all successors. */
2590 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2596 unsigned int to = find (j);
2597 tmp = get_varinfo (to)->solution;
2600 /* Don't try to propagate to ourselves. */
2604 /* If we propagate from ESCAPED use ESCAPED as
2606 if (i == eff_escaped_id)
2607 flag = bitmap_set_bit (tmp, escaped_id);
2609 flag = set_union_with_increment (tmp, pts, 0);
2613 get_varinfo (to)->solution = tmp;
2614 bitmap_set_bit (changed, to);
2620 free_topo_info (ti);
2621 bitmap_obstack_release (&iteration_obstack);
2625 BITMAP_FREE (changed);
2626 bitmap_obstack_release (&oldpta_obstack);
2629 /* Map from trees to variable infos. */
2630 static struct pointer_map_t *vi_for_tree;
2633 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2636 insert_vi_for_tree (tree t, varinfo_t vi)
2638 void **slot = pointer_map_insert (vi_for_tree, t);
2640 gcc_assert (*slot == NULL);
2644 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2645 exist in the map, return NULL, otherwise, return the varinfo we found. */
2648 lookup_vi_for_tree (tree t)
2650 void **slot = pointer_map_contains (vi_for_tree, t);
2654 return (varinfo_t) *slot;
2657 /* Return a printable name for DECL */
2660 alias_get_name (tree decl)
2664 int num_printed = 0;
2666 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2667 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2669 res= get_name (decl);
2677 if (TREE_CODE (decl) == SSA_NAME)
2679 num_printed = asprintf (&temp, "%s_%u",
2680 alias_get_name (SSA_NAME_VAR (decl)),
2681 SSA_NAME_VERSION (decl));
2683 else if (DECL_P (decl))
2685 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2687 if (num_printed > 0)
2689 res = ggc_strdup (temp);
2695 /* Find the variable id for tree T in the map.
2696 If T doesn't exist in the map, create an entry for it and return it. */
2699 get_vi_for_tree (tree t)
2701 void **slot = pointer_map_contains (vi_for_tree, t);
2703 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2705 return (varinfo_t) *slot;
2708 /* Get a scalar constraint expression for a new temporary variable. */
2710 static struct constraint_expr
2711 new_scalar_tmp_constraint_exp (const char *name)
2713 struct constraint_expr tmp;
2716 vi = new_var_info (NULL_TREE, name);
2720 vi->is_full_var = 1;
2729 /* Get a constraint expression vector from an SSA_VAR_P node.
2730 If address_p is true, the result will be taken its address of. */
2733 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2735 struct constraint_expr cexpr;
2738 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2739 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2741 /* For parameters, get at the points-to set for the actual parm
2743 if (TREE_CODE (t) == SSA_NAME
2744 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2745 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2746 && SSA_NAME_IS_DEFAULT_DEF (t))
2748 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2752 vi = get_vi_for_tree (t);
2754 cexpr.type = SCALAR;
2756 /* If we determine the result is "anything", and we know this is readonly,
2757 say it points to readonly memory instead. */
2758 if (cexpr.var == anything_id && TREE_READONLY (t))
2761 cexpr.type = ADDRESSOF;
2762 cexpr.var = readonly_id;
2765 /* If we are not taking the address of the constraint expr, add all
2766 sub-fiels of the variable as well. */
2768 && !vi->is_full_var)
2770 for (; vi; vi = vi->next)
2773 VEC_safe_push (ce_s, heap, *results, &cexpr);
2778 VEC_safe_push (ce_s, heap, *results, &cexpr);
2781 /* Process constraint T, performing various simplifications and then
2782 adding it to our list of overall constraints. */
2785 process_constraint (constraint_t t)
2787 struct constraint_expr rhs = t->rhs;
2788 struct constraint_expr lhs = t->lhs;
2790 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2791 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2793 /* If we didn't get any useful constraint from the lhs we get
2794 &ANYTHING as fallback from get_constraint_for. Deal with
2795 it here by turning it into *ANYTHING. */
2796 if (lhs.type == ADDRESSOF
2797 && lhs.var == anything_id)
2800 /* ADDRESSOF on the lhs is invalid. */
2801 gcc_assert (lhs.type != ADDRESSOF);
2803 /* We shouldn't add constraints from things that cannot have pointers.
2804 It's not completely trivial to avoid in the callers, so do it here. */
2805 if (rhs.type != ADDRESSOF
2806 && !get_varinfo (rhs.var)->may_have_pointers)
2809 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2810 if (!get_varinfo (lhs.var)->may_have_pointers)
2813 /* This can happen in our IR with things like n->a = *p */
2814 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2816 /* Split into tmp = *rhs, *lhs = tmp */
2817 struct constraint_expr tmplhs;
2818 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2819 process_constraint (new_constraint (tmplhs, rhs));
2820 process_constraint (new_constraint (lhs, tmplhs));
2822 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2824 /* Split into tmp = &rhs, *lhs = tmp */
2825 struct constraint_expr tmplhs;
2826 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2827 process_constraint (new_constraint (tmplhs, rhs));
2828 process_constraint (new_constraint (lhs, tmplhs));
2832 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2833 VEC_safe_push (constraint_t, heap, constraints, t);
2838 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2841 static HOST_WIDE_INT
2842 bitpos_of_field (const tree fdecl)
2844 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2845 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2848 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2849 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2853 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2854 resulting constraint expressions in *RESULTS. */
2857 get_constraint_for_ptr_offset (tree ptr, tree offset,
2858 VEC (ce_s, heap) **results)
2860 struct constraint_expr c;
2862 HOST_WIDE_INT rhsunitoffset, rhsoffset;
2864 /* If we do not do field-sensitive PTA adding offsets to pointers
2865 does not change the points-to solution. */
2866 if (!use_field_sensitive)
2868 get_constraint_for_rhs (ptr, results);
2872 /* If the offset is not a non-negative integer constant that fits
2873 in a HOST_WIDE_INT, we have to fall back to a conservative
2874 solution which includes all sub-fields of all pointed-to
2875 variables of ptr. */
2876 if (offset == NULL_TREE
2877 || !host_integerp (offset, 0))
2878 rhsoffset = UNKNOWN_OFFSET;
2881 /* Make sure the bit-offset also fits. */
2882 rhsunitoffset = TREE_INT_CST_LOW (offset);
2883 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2884 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2885 rhsoffset = UNKNOWN_OFFSET;
2888 get_constraint_for_rhs (ptr, results);
2892 /* As we are eventually appending to the solution do not use
2893 VEC_iterate here. */
2894 n = VEC_length (ce_s, *results);
2895 for (j = 0; j < n; j++)
2898 c = *VEC_index (ce_s, *results, j);
2899 curr = get_varinfo (c.var);
2901 if (c.type == ADDRESSOF
2902 /* If this varinfo represents a full variable just use it. */
2903 && curr->is_full_var)
2905 else if (c.type == ADDRESSOF
2906 /* If we do not know the offset add all subfields. */
2907 && rhsoffset == UNKNOWN_OFFSET)
2909 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2912 struct constraint_expr c2;
2914 c2.type = ADDRESSOF;
2916 if (c2.var != c.var)
2917 VEC_safe_push (ce_s, heap, *results, &c2);
2922 else if (c.type == ADDRESSOF)
2925 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2927 /* Search the sub-field which overlaps with the
2928 pointed-to offset. If the result is outside of the variable
2929 we have to provide a conservative result, as the variable is
2930 still reachable from the resulting pointer (even though it
2931 technically cannot point to anything). The last and first
2932 sub-fields are such conservative results.
2933 ??? If we always had a sub-field for &object + 1 then
2934 we could represent this in a more precise way. */
2936 && curr->offset < offset)
2938 temp = first_or_preceding_vi_for_offset (curr, offset);
2940 /* If the found variable is not exactly at the pointed to
2941 result, we have to include the next variable in the
2942 solution as well. Otherwise two increments by offset / 2
2943 do not result in the same or a conservative superset
2945 if (temp->offset != offset
2946 && temp->next != NULL)
2948 struct constraint_expr c2;
2949 c2.var = temp->next->id;
2950 c2.type = ADDRESSOF;
2952 VEC_safe_push (ce_s, heap, *results, &c2);
2958 c.offset = rhsoffset;
2960 VEC_replace (ce_s, *results, j, &c);
2965 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2966 If address_p is true the result will be taken its address of.
2967 If lhs_p is true then the constraint expression is assumed to be used
2971 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2972 bool address_p, bool lhs_p)
2975 HOST_WIDE_INT bitsize = -1;
2976 HOST_WIDE_INT bitmaxsize = -1;
2977 HOST_WIDE_INT bitpos;
2979 struct constraint_expr *result;
2981 /* Some people like to do cute things like take the address of
2984 while (handled_component_p (forzero)
2985 || INDIRECT_REF_P (forzero)
2986 || TREE_CODE (forzero) == MEM_REF)
2987 forzero = TREE_OPERAND (forzero, 0);
2989 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
2991 struct constraint_expr temp;
2994 temp.var = integer_id;
2996 VEC_safe_push (ce_s, heap, *results, &temp);
3000 /* Handle type-punning through unions. If we are extracting a pointer
3001 from a union via a possibly type-punning access that pointer
3002 points to anything, similar to a conversion of an integer to
3008 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3009 u = TREE_OPERAND (u, 0))
3010 if (TREE_CODE (u) == COMPONENT_REF
3011 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3013 struct constraint_expr temp;
3016 temp.var = anything_id;
3017 temp.type = ADDRESSOF;
3018 VEC_safe_push (ce_s, heap, *results, &temp);
3023 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3025 /* Pretend to take the address of the base, we'll take care of
3026 adding the required subset of sub-fields below. */
3027 get_constraint_for_1 (t, results, true, lhs_p);
3028 gcc_assert (VEC_length (ce_s, *results) == 1);
3029 result = VEC_last (ce_s, *results);
3031 if (result->type == SCALAR
3032 && get_varinfo (result->var)->is_full_var)
3033 /* For single-field vars do not bother about the offset. */
3035 else if (result->type == SCALAR)
3037 /* In languages like C, you can access one past the end of an
3038 array. You aren't allowed to dereference it, so we can
3039 ignore this constraint. When we handle pointer subtraction,
3040 we may have to do something cute here. */
3042 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3045 /* It's also not true that the constraint will actually start at the
3046 right offset, it may start in some padding. We only care about
3047 setting the constraint to the first actual field it touches, so
3049 struct constraint_expr cexpr = *result;
3051 VEC_pop (ce_s, *results);
3053 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3055 if (ranges_overlap_p (curr->offset, curr->size,
3056 bitpos, bitmaxsize))
3058 cexpr.var = curr->id;
3059 VEC_safe_push (ce_s, heap, *results, &cexpr);
3064 /* If we are going to take the address of this field then
3065 to be able to compute reachability correctly add at least
3066 the last field of the variable. */
3068 && VEC_length (ce_s, *results) == 0)
3070 curr = get_varinfo (cexpr.var);
3071 while (curr->next != NULL)
3073 cexpr.var = curr->id;
3074 VEC_safe_push (ce_s, heap, *results, &cexpr);
3076 else if (VEC_length (ce_s, *results) == 0)
3077 /* Assert that we found *some* field there. The user couldn't be
3078 accessing *only* padding. */
3079 /* Still the user could access one past the end of an array
3080 embedded in a struct resulting in accessing *only* padding. */
3081 /* Or accessing only padding via type-punning to a type
3082 that has a filed just in padding space. */
3084 cexpr.type = SCALAR;
3085 cexpr.var = anything_id;
3087 VEC_safe_push (ce_s, heap, *results, &cexpr);
3090 else if (bitmaxsize == 0)
3092 if (dump_file && (dump_flags & TDF_DETAILS))
3093 fprintf (dump_file, "Access to zero-sized part of variable,"
3097 if (dump_file && (dump_flags & TDF_DETAILS))
3098 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3100 else if (result->type == DEREF)
3102 /* If we do not know exactly where the access goes say so. Note
3103 that only for non-structure accesses we know that we access
3104 at most one subfiled of any variable. */
3106 || bitsize != bitmaxsize
3107 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3108 || result->offset == UNKNOWN_OFFSET)
3109 result->offset = UNKNOWN_OFFSET;
3111 result->offset += bitpos;
3113 else if (result->type == ADDRESSOF)
3115 /* We can end up here for component references on a
3116 VIEW_CONVERT_EXPR <>(&foobar). */
3117 result->type = SCALAR;
3118 result->var = anything_id;
3126 /* Dereference the constraint expression CONS, and return the result.
3127 DEREF (ADDRESSOF) = SCALAR
3128 DEREF (SCALAR) = DEREF
3129 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3130 This is needed so that we can handle dereferencing DEREF constraints. */
3133 do_deref (VEC (ce_s, heap) **constraints)
3135 struct constraint_expr *c;
3138 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3140 if (c->type == SCALAR)
3142 else if (c->type == ADDRESSOF)
3144 else if (c->type == DEREF)
3146 struct constraint_expr tmplhs;
3147 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3148 process_constraint (new_constraint (tmplhs, *c));
3149 c->var = tmplhs.var;
3156 /* Given a tree T, return the constraint expression for taking the
3160 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3162 struct constraint_expr *c;
3165 get_constraint_for_1 (t, results, true, true);
3167 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3169 if (c->type == DEREF)
3172 c->type = ADDRESSOF;
3176 /* Given a tree T, return the constraint expression for it. */
3179 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3182 struct constraint_expr temp;
3184 /* x = integer is all glommed to a single variable, which doesn't
3185 point to anything by itself. That is, of course, unless it is an
3186 integer constant being treated as a pointer, in which case, we
3187 will return that this is really the addressof anything. This
3188 happens below, since it will fall into the default case. The only
3189 case we know something about an integer treated like a pointer is
3190 when it is the NULL pointer, and then we just say it points to
3193 Do not do that if -fno-delete-null-pointer-checks though, because
3194 in that case *NULL does not fail, so it _should_ alias *anything.
3195 It is not worth adding a new option or renaming the existing one,
3196 since this case is relatively obscure. */
3197 if ((TREE_CODE (t) == INTEGER_CST
3198 && integer_zerop (t))
3199 /* The only valid CONSTRUCTORs in gimple with pointer typed
3200 elements are zero-initializer. But in IPA mode we also
3201 process global initializers, so verify at least. */
3202 || (TREE_CODE (t) == CONSTRUCTOR
3203 && CONSTRUCTOR_NELTS (t) == 0))
3205 if (flag_delete_null_pointer_checks)
3206 temp.var = nothing_id;
3208 temp.var = nonlocal_id;
3209 temp.type = ADDRESSOF;
3211 VEC_safe_push (ce_s, heap, *results, &temp);
3215 /* String constants are read-only. */
3216 if (TREE_CODE (t) == STRING_CST)
3218 temp.var = readonly_id;
3221 VEC_safe_push (ce_s, heap, *results, &temp);
3225 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3227 case tcc_expression:
3229 switch (TREE_CODE (t))
3232 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3240 switch (TREE_CODE (t))
3244 struct constraint_expr cs;
3246 tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
3247 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
3250 /* If we are not taking the address then make sure to process
3251 all subvariables we might access. */
3252 cs = *VEC_last (ce_s, *results);
3254 || cs.type != SCALAR)
3257 vi = get_varinfo (cs.var);
3259 if (!vi->is_full_var
3262 unsigned HOST_WIDE_INT size;
3263 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3264 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3267 for (; curr; curr = curr->next)
3269 if (curr->offset - vi->offset < size)
3272 VEC_safe_push (ce_s, heap, *results, &cs);
3281 case ARRAY_RANGE_REF:
3283 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3285 case VIEW_CONVERT_EXPR:
3286 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3289 /* We are missing handling for TARGET_MEM_REF here. */
3294 case tcc_exceptional:
3296 switch (TREE_CODE (t))
3300 get_constraint_for_ssa_var (t, results, address_p);
3307 VEC (ce_s, heap) *tmp = NULL;
3308 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3310 struct constraint_expr *rhsp;
3312 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3313 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3314 VEC_safe_push (ce_s, heap, *results, rhsp);
3315 VEC_truncate (ce_s, tmp, 0);
3317 VEC_free (ce_s, heap, tmp);
3318 /* We do not know whether the constructor was complete,
3319 so technically we have to add &NOTHING or &ANYTHING
3320 like we do for an empty constructor as well. */
3327 case tcc_declaration:
3329 get_constraint_for_ssa_var (t, results, address_p);
3334 /* We cannot refer to automatic variables through constants. */
3335 temp.type = ADDRESSOF;
3336 temp.var = nonlocal_id;
3338 VEC_safe_push (ce_s, heap, *results, &temp);
3344 /* The default fallback is a constraint from anything. */
3345 temp.type = ADDRESSOF;
3346 temp.var = anything_id;
3348 VEC_safe_push (ce_s, heap, *results, &temp);
3351 /* Given a gimple tree T, return the constraint expression vector for it. */
3354 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3356 gcc_assert (VEC_length (ce_s, *results) == 0);
3358 get_constraint_for_1 (t, results, false, true);
3361 /* Given a gimple tree T, return the constraint expression vector for it
3362 to be used as the rhs of a constraint. */
3365 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3367 gcc_assert (VEC_length (ce_s, *results) == 0);
3369 get_constraint_for_1 (t, results, false, false);
3373 /* Efficiently generates constraints from all entries in *RHSC to all
3374 entries in *LHSC. */
3377 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3379 struct constraint_expr *lhsp, *rhsp;
3382 if (VEC_length (ce_s, lhsc) <= 1
3383 || VEC_length (ce_s, rhsc) <= 1)
3385 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3386 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3387 process_constraint (new_constraint (*lhsp, *rhsp));
3391 struct constraint_expr tmp;
3392 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3393 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3394 process_constraint (new_constraint (tmp, *rhsp));
3395 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3396 process_constraint (new_constraint (*lhsp, tmp));
3400 /* Handle aggregate copies by expanding into copies of the respective
3401 fields of the structures. */
3404 do_structure_copy (tree lhsop, tree rhsop)
3406 struct constraint_expr *lhsp, *rhsp;
3407 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3410 get_constraint_for (lhsop, &lhsc);
3411 get_constraint_for_rhs (rhsop, &rhsc);
3412 lhsp = VEC_index (ce_s, lhsc, 0);
3413 rhsp = VEC_index (ce_s, rhsc, 0);
3414 if (lhsp->type == DEREF
3415 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3416 || rhsp->type == DEREF)
3418 if (lhsp->type == DEREF)
3420 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3421 lhsp->offset = UNKNOWN_OFFSET;
3423 if (rhsp->type == DEREF)
3425 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3426 rhsp->offset = UNKNOWN_OFFSET;
3428 process_all_all_constraints (lhsc, rhsc);
3430 else if (lhsp->type == SCALAR
3431 && (rhsp->type == SCALAR
3432 || rhsp->type == ADDRESSOF))
3434 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3435 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3437 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3438 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3439 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3441 varinfo_t lhsv, rhsv;
3442 rhsp = VEC_index (ce_s, rhsc, k);
3443 lhsv = get_varinfo (lhsp->var);
3444 rhsv = get_varinfo (rhsp->var);
3445 if (lhsv->may_have_pointers
3446 && (lhsv->is_full_var
3447 || rhsv->is_full_var
3448 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3449 rhsv->offset + lhsoffset, rhsv->size)))
3450 process_constraint (new_constraint (*lhsp, *rhsp));
3451 if (!rhsv->is_full_var
3452 && (lhsv->is_full_var
3453 || (lhsv->offset + rhsoffset + lhsv->size
3454 > rhsv->offset + lhsoffset + rhsv->size)))
3457 if (k >= VEC_length (ce_s, rhsc))
3467 VEC_free (ce_s, heap, lhsc);
3468 VEC_free (ce_s, heap, rhsc);
3471 /* Create constraints ID = { rhsc }. */
3474 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3476 struct constraint_expr *c;
3477 struct constraint_expr includes;
3481 includes.offset = 0;
3482 includes.type = SCALAR;
3484 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3485 process_constraint (new_constraint (includes, *c));
3488 /* Create a constraint ID = OP. */
3491 make_constraint_to (unsigned id, tree op)
3493 VEC(ce_s, heap) *rhsc = NULL;
3494 get_constraint_for_rhs (op, &rhsc);
3495 make_constraints_to (id, rhsc);
3496 VEC_free (ce_s, heap, rhsc);
3499 /* Create a constraint ID = &FROM. */
3502 make_constraint_from (varinfo_t vi, int from)
3504 struct constraint_expr lhs, rhs;
3512 rhs.type = ADDRESSOF;
3513 process_constraint (new_constraint (lhs, rhs));
3516 /* Create a constraint ID = FROM. */
3519 make_copy_constraint (varinfo_t vi, int from)
3521 struct constraint_expr lhs, rhs;
3530 process_constraint (new_constraint (lhs, rhs));
3533 /* Make constraints necessary to make OP escape. */
3536 make_escape_constraint (tree op)
3538 make_constraint_to (escaped_id, op);
3541 /* Add constraints to that the solution of VI is transitively closed. */
3544 make_transitive_closure_constraints (varinfo_t vi)
3546 struct constraint_expr lhs, rhs;
3555 process_constraint (new_constraint (lhs, rhs));
3557 /* VAR = VAR + UNKNOWN; */
3563 rhs.offset = UNKNOWN_OFFSET;
3564 process_constraint (new_constraint (lhs, rhs));
3567 /* Temporary storage for fake var decls. */
3568 struct obstack fake_var_decl_obstack;
3570 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
3573 build_fake_var_decl (tree type)
3575 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
3576 memset (decl, 0, sizeof (struct tree_var_decl));
3577 TREE_SET_CODE (decl, VAR_DECL);
3578 TREE_TYPE (decl) = type;
3579 DECL_UID (decl) = allocate_decl_uid ();
3580 SET_DECL_PT_UID (decl, -1);
3581 layout_decl (decl, 0);
3585 /* Create a new artificial heap variable with NAME.
3586 Return the created variable. */
3589 make_heapvar (const char *name)
3594 heapvar = build_fake_var_decl (ptr_type_node);
3595 DECL_EXTERNAL (heapvar) = 1;
3597 vi = new_var_info (heapvar, name);
3598 vi->is_artificial_var = true;
3599 vi->is_heap_var = true;
3600 vi->is_unknown_size_var = true;
3604 vi->is_full_var = true;
3605 insert_vi_for_tree (heapvar, vi);
3610 /* Create a new artificial heap variable with NAME and make a
3611 constraint from it to LHS. Return the created variable. */
3614 make_constraint_from_heapvar (varinfo_t lhs, const char *name)
3616 varinfo_t vi = make_heapvar (name);
3617 make_constraint_from (lhs, vi->id);
3622 /* Create a new artificial heap variable with NAME and make a
3623 constraint from it to LHS. Set flags according to a tag used
3624 for tracking restrict pointers. */
3627 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3630 vi = make_constraint_from_heapvar (lhs, name);
3631 vi->is_restrict_var = 1;
3632 vi->is_global_var = 0;
3633 vi->is_special_var = 1;
3634 vi->may_have_pointers = 0;
3637 /* In IPA mode there are varinfos for different aspects of reach
3638 function designator. One for the points-to set of the return
3639 value, one for the variables that are clobbered by the function,
3640 one for its uses and one for each parameter (including a single
3641 glob for remaining variadic arguments). */
3643 enum { fi_clobbers = 1, fi_uses = 2,
3644 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3646 /* Get a constraint for the requested part of a function designator FI
3647 when operating in IPA mode. */
3649 static struct constraint_expr
3650 get_function_part_constraint (varinfo_t fi, unsigned part)
3652 struct constraint_expr c;
3654 gcc_assert (in_ipa_mode);
3656 if (fi->id == anything_id)
3658 /* ??? We probably should have a ANYFN special variable. */
3659 c.var = anything_id;
3663 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3665 varinfo_t ai = first_vi_for_offset (fi, part);
3669 c.var = anything_id;
3683 /* For non-IPA mode, generate constraints necessary for a call on the
3687 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3689 struct constraint_expr rhsc;
3691 bool returns_uses = false;
3693 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3695 tree arg = gimple_call_arg (stmt, i);
3696 int flags = gimple_call_arg_flags (stmt, i);
3698 /* If the argument is not used we can ignore it. */
3699 if (flags & EAF_UNUSED)
3702 /* As we compute ESCAPED context-insensitive we do not gain
3703 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3704 set. The argument would still get clobbered through the
3706 ??? We might get away with less (and more precise) constraints
3707 if using a temporary for transitively closing things. */
3708 if ((flags & EAF_NOCLOBBER)
3709 && (flags & EAF_NOESCAPE))
3711 varinfo_t uses = get_call_use_vi (stmt);
3712 if (!(flags & EAF_DIRECT))
3713 make_transitive_closure_constraints (uses);
3714 make_constraint_to (uses->id, arg);
3715 returns_uses = true;
3717 else if (flags & EAF_NOESCAPE)
3719 varinfo_t uses = get_call_use_vi (stmt);
3720 varinfo_t clobbers = get_call_clobber_vi (stmt);
3721 if (!(flags & EAF_DIRECT))
3723 make_transitive_closure_constraints (uses);
3724 make_transitive_closure_constraints (clobbers);
3726 make_constraint_to (uses->id, arg);
3727 make_constraint_to (clobbers->id, arg);
3728 returns_uses = true;
3731 make_escape_constraint (arg);
3734 /* If we added to the calls uses solution make sure we account for
3735 pointers to it to be returned. */
3738 rhsc.var = get_call_use_vi (stmt)->id;
3741 VEC_safe_push (ce_s, heap, *results, &rhsc);
3744 /* The static chain escapes as well. */
3745 if (gimple_call_chain (stmt))
3746 make_escape_constraint (gimple_call_chain (stmt));
3748 /* And if we applied NRV the address of the return slot escapes as well. */
3749 if (gimple_call_return_slot_opt_p (stmt)
3750 && gimple_call_lhs (stmt) != NULL_TREE
3751 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3753 VEC(ce_s, heap) *tmpc = NULL;
3754 struct constraint_expr lhsc, *c;
3755 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3756 lhsc.var = escaped_id;
3759 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3760 process_constraint (new_constraint (lhsc, *c));
3761 VEC_free(ce_s, heap, tmpc);
3764 /* Regular functions return nonlocal memory. */
3765 rhsc.var = nonlocal_id;
3768 VEC_safe_push (ce_s, heap, *results, &rhsc);
3771 /* For non-IPA mode, generate constraints necessary for a call
3772 that returns a pointer and assigns it to LHS. This simply makes
3773 the LHS point to global and escaped variables. */
3776 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3779 VEC(ce_s, heap) *lhsc = NULL;
3781 get_constraint_for (lhs, &lhsc);
3782 /* If the store is to a global decl make sure to
3783 add proper escape constraints. */
3784 lhs = get_base_address (lhs);
3787 && is_global_var (lhs))
3789 struct constraint_expr tmpc;
3790 tmpc.var = escaped_id;
3793 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3796 /* If the call returns an argument unmodified override the rhs
3798 flags = gimple_call_return_flags (stmt);
3799 if (flags & ERF_RETURNS_ARG
3800 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3804 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3805 get_constraint_for (arg, &rhsc);
3806 process_all_all_constraints (lhsc, rhsc);
3807 VEC_free (ce_s, heap, rhsc);
3809 else if (flags & ERF_NOALIAS)
3812 struct constraint_expr tmpc;
3814 vi = make_heapvar ("HEAP");
3815 /* We delay marking allocated storage global until we know if
3817 DECL_EXTERNAL (vi->decl) = 0;
3818 vi->is_global_var = 0;
3819 /* If this is not a real malloc call assume the memory was
3820 initialized and thus may point to global memory. All
3821 builtin functions with the malloc attribute behave in a sane way. */
3823 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3824 make_constraint_from (vi, nonlocal_id);
3827 tmpc.type = ADDRESSOF;
3828 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3831 process_all_all_constraints (lhsc, rhsc);
3833 VEC_free (ce_s, heap, lhsc);
3836 /* For non-IPA mode, generate constraints necessary for a call of a
3837 const function that returns a pointer in the statement STMT. */
3840 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3842 struct constraint_expr rhsc;
3845 /* Treat nested const functions the same as pure functions as far
3846 as the static chain is concerned. */
3847 if (gimple_call_chain (stmt))
3849 varinfo_t uses = get_call_use_vi (stmt);
3850 make_transitive_closure_constraints (uses);
3851 make_constraint_to (uses->id, gimple_call_chain (stmt));
3852 rhsc.var = uses->id;
3855 VEC_safe_push (ce_s, heap, *results, &rhsc);
3858 /* May return arguments. */
3859 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3861 tree arg = gimple_call_arg (stmt, k);
3862 VEC(ce_s, heap) *argc = NULL;
3864 struct constraint_expr *argp;
3865 get_constraint_for_rhs (arg, &argc);
3866 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3867 VEC_safe_push (ce_s, heap, *results, argp);
3868 VEC_free(ce_s, heap, argc);
3871 /* May return addresses of globals. */
3872 rhsc.var = nonlocal_id;
3874 rhsc.type = ADDRESSOF;
3875 VEC_safe_push (ce_s, heap, *results, &rhsc);
3878 /* For non-IPA mode, generate constraints necessary for a call to a
3879 pure function in statement STMT. */
3882 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3884 struct constraint_expr rhsc;
3886 varinfo_t uses = NULL;
3888 /* Memory reached from pointer arguments is call-used. */
3889 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3891 tree arg = gimple_call_arg (stmt, i);
3894 uses = get_call_use_vi (stmt);
3895 make_transitive_closure_constraints (uses);
3897 make_constraint_to (uses->id, arg);
3900 /* The static chain is used as well. */
3901 if (gimple_call_chain (stmt))
3905 uses = get_call_use_vi (stmt);
3906 make_transitive_closure_constraints (uses);
3908 make_constraint_to (uses->id, gimple_call_chain (stmt));
3911 /* Pure functions may return call-used and nonlocal memory. */
3914 rhsc.var = uses->id;
3917 VEC_safe_push (ce_s, heap, *results, &rhsc);
3919 rhsc.var = nonlocal_id;
3922 VEC_safe_push (ce_s, heap, *results, &rhsc);
3926 /* Return the varinfo for the callee of CALL. */
3929 get_fi_for_callee (gimple call)
3933 gcc_assert (!gimple_call_internal_p (call));
3935 /* If we can directly resolve the function being called, do so.
3936 Otherwise, it must be some sort of indirect expression that
3937 we should still be able to handle. */
3938 decl = gimple_call_fndecl (call);
3940 return get_vi_for_tree (decl);
3942 decl = gimple_call_fn (call);
3943 /* The function can be either an SSA name pointer or,
3944 worse, an OBJ_TYPE_REF. In this case we have no
3945 clue and should be getting ANYFN (well, ANYTHING for now). */
3946 if (TREE_CODE (decl) == SSA_NAME)
3948 if (TREE_CODE (decl) == SSA_NAME
3949 && (TREE_CODE (SSA_NAME_VAR (decl)) == PARM_DECL
3950 || TREE_CODE (SSA_NAME_VAR (decl)) == RESULT_DECL)
3951 && SSA_NAME_IS_DEFAULT_DEF (decl))
3952 decl = SSA_NAME_VAR (decl);
3953 return get_vi_for_tree (decl);
3955 else if (TREE_CODE (decl) == INTEGER_CST
3956 || TREE_CODE (decl) == OBJ_TYPE_REF)
3957 return get_varinfo (anything_id);
3962 /* Create constraints for the builtin call T. Return true if the call
3963 was handled, otherwise false. */
3966 find_func_aliases_for_builtin_call (gimple t)
3968 tree fndecl = gimple_call_fndecl (t);
3969 VEC(ce_s, heap) *lhsc = NULL;
3970 VEC(ce_s, heap) *rhsc = NULL;
3973 if (fndecl != NULL_TREE
3974 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
3975 /* ??? All builtins that are handled here need to be handled
3976 in the alias-oracle query functions explicitly! */
3977 switch (DECL_FUNCTION_CODE (fndecl))
3979 /* All the following functions return a pointer to the same object
3980 as their first argument points to. The functions do not add
3981 to the ESCAPED solution. The functions make the first argument
3982 pointed to memory point to what the second argument pointed to
3983 memory points to. */
3984 case BUILT_IN_STRCPY:
3985 case BUILT_IN_STRNCPY:
3986 case BUILT_IN_BCOPY:
3987 case BUILT_IN_MEMCPY:
3988 case BUILT_IN_MEMMOVE:
3989 case BUILT_IN_MEMPCPY:
3990 case BUILT_IN_STPCPY:
3991 case BUILT_IN_STPNCPY:
3992 case BUILT_IN_STRCAT:
3993 case BUILT_IN_STRNCAT:
3995 tree res = gimple_call_lhs (t);
3996 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
3997 == BUILT_IN_BCOPY ? 1 : 0));
3998 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
3999 == BUILT_IN_BCOPY ? 0 : 1));
4000 if (res != NULL_TREE)
4002 get_constraint_for (res, &lhsc);
4003 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4004 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4005 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY)
4006 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4008 get_constraint_for (dest, &rhsc);
4009 process_all_all_constraints (lhsc, rhsc);
4010 VEC_free (ce_s, heap, lhsc);
4011 VEC_free (ce_s, heap, rhsc);
4013 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4014 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4017 process_all_all_constraints (lhsc, rhsc);
4018 VEC_free (ce_s, heap, lhsc);
4019 VEC_free (ce_s, heap, rhsc);
4022 case BUILT_IN_MEMSET:
4024 tree res = gimple_call_lhs (t);
4025 tree dest = gimple_call_arg (t, 0);
4028 struct constraint_expr ac;
4029 if (res != NULL_TREE)
4031 get_constraint_for (res, &lhsc);
4032 get_constraint_for (dest, &rhsc);
4033 process_all_all_constraints (lhsc, rhsc);
4034 VEC_free (ce_s, heap, lhsc);
4035 VEC_free (ce_s, heap, rhsc);
4037 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4039 if (flag_delete_null_pointer_checks
4040 && integer_zerop (gimple_call_arg (t, 1)))
4042 ac.type = ADDRESSOF;
4043 ac.var = nothing_id;
4048 ac.var = integer_id;
4051 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4052 process_constraint (new_constraint (*lhsp, ac));
4053 VEC_free (ce_s, heap, lhsc);
4056 /* All the following functions do not return pointers, do not
4057 modify the points-to sets of memory reachable from their
4058 arguments and do not add to the ESCAPED solution. */
4059 case BUILT_IN_SINCOS:
4060 case BUILT_IN_SINCOSF:
4061 case BUILT_IN_SINCOSL:
4062 case BUILT_IN_FREXP:
4063 case BUILT_IN_FREXPF:
4064 case BUILT_IN_FREXPL:
4065 case BUILT_IN_GAMMA_R:
4066 case BUILT_IN_GAMMAF_R:
4067 case BUILT_IN_GAMMAL_R:
4068 case BUILT_IN_LGAMMA_R:
4069 case BUILT_IN_LGAMMAF_R:
4070 case BUILT_IN_LGAMMAL_R:
4072 case BUILT_IN_MODFF:
4073 case BUILT_IN_MODFL:
4074 case BUILT_IN_REMQUO:
4075 case BUILT_IN_REMQUOF:
4076 case BUILT_IN_REMQUOL:
4079 /* Trampolines are special - they set up passing the static
4081 case BUILT_IN_INIT_TRAMPOLINE:
4083 tree tramp = gimple_call_arg (t, 0);
4084 tree nfunc = gimple_call_arg (t, 1);
4085 tree frame = gimple_call_arg (t, 2);
4087 struct constraint_expr lhs, *rhsp;
4090 varinfo_t nfi = NULL;
4091 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4092 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4095 lhs = get_function_part_constraint (nfi, fi_static_chain);
4096 get_constraint_for (frame, &rhsc);
4097 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4098 process_constraint (new_constraint (lhs, *rhsp));
4099 VEC_free (ce_s, heap, rhsc);
4101 /* Make the frame point to the function for
4102 the trampoline adjustment call. */
4103 get_constraint_for (tramp, &lhsc);
4105 get_constraint_for (nfunc, &rhsc);
4106 process_all_all_constraints (lhsc, rhsc);
4107 VEC_free (ce_s, heap, rhsc);
4108 VEC_free (ce_s, heap, lhsc);
4113 /* Else fallthru to generic handling which will let
4114 the frame escape. */
4117 case BUILT_IN_ADJUST_TRAMPOLINE:
4119 tree tramp = gimple_call_arg (t, 0);
4120 tree res = gimple_call_lhs (t);
4121 if (in_ipa_mode && res)
4123 get_constraint_for (res, &lhsc);
4124 get_constraint_for (tramp, &rhsc);
4126 process_all_all_constraints (lhsc, rhsc);
4127 VEC_free (ce_s, heap, rhsc);
4128 VEC_free (ce_s, heap, lhsc);
4132 /* Variadic argument handling needs to be handled in IPA
4134 case BUILT_IN_VA_START:
4138 tree valist = gimple_call_arg (t, 0);
4139 struct constraint_expr rhs, *lhsp;
4141 /* The va_list gets access to pointers in variadic
4143 fi = lookup_vi_for_tree (cfun->decl);
4144 gcc_assert (fi != NULL);
4145 get_constraint_for (valist, &lhsc);
4147 rhs = get_function_part_constraint (fi, ~0);
4148 rhs.type = ADDRESSOF;
4149 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4150 process_constraint (new_constraint (*lhsp, rhs));
4151 VEC_free (ce_s, heap, lhsc);
4152 /* va_list is clobbered. */
4153 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4158 /* va_end doesn't have any effect that matters. */
4159 case BUILT_IN_VA_END:
4161 /* Alternate return. Simply give up for now. */
4162 case BUILT_IN_RETURN:
4166 || !(fi = get_vi_for_tree (cfun->decl)))
4167 make_constraint_from (get_varinfo (escaped_id), anything_id);
4168 else if (in_ipa_mode
4171 struct constraint_expr lhs, rhs;
4172 lhs = get_function_part_constraint (fi, fi_result);
4173 rhs.var = anything_id;
4176 process_constraint (new_constraint (lhs, rhs));
4180 /* printf-style functions may have hooks to set pointers to
4181 point to somewhere into the generated string. Leave them
4182 for a later excercise... */
4184 /* Fallthru to general call handling. */;
4190 /* Create constraints for the call T. */
4193 find_func_aliases_for_call (gimple t)
4195 tree fndecl = gimple_call_fndecl (t);
4196 VEC(ce_s, heap) *lhsc = NULL;
4197 VEC(ce_s, heap) *rhsc = NULL;
4200 if (fndecl != NULL_TREE
4201 && DECL_BUILT_IN (fndecl)
4202 && find_func_aliases_for_builtin_call (t))
4206 || gimple_call_internal_p (t)
4208 && (!(fi = lookup_vi_for_tree (fndecl))
4209 || !fi->is_fn_info)))
4211 VEC(ce_s, heap) *rhsc = NULL;
4212 int flags = gimple_call_flags (t);
4214 /* Const functions can return their arguments and addresses
4215 of global memory but not of escaped memory. */
4216 if (flags & (ECF_CONST|ECF_NOVOPS))
4218 if (gimple_call_lhs (t))
4219 handle_const_call (t, &rhsc);
4221 /* Pure functions can return addresses in and of memory
4222 reachable from their arguments, but they are not an escape
4223 point for reachable memory of their arguments. */
4224 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4225 handle_pure_call (t, &rhsc);
4227 handle_rhs_call (t, &rhsc);
4228 if (gimple_call_lhs (t))
4229 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4230 VEC_free (ce_s, heap, rhsc);
4237 fi = get_fi_for_callee (t);
4239 /* Assign all the passed arguments to the appropriate incoming
4240 parameters of the function. */
4241 for (j = 0; j < gimple_call_num_args (t); j++)
4243 struct constraint_expr lhs ;
4244 struct constraint_expr *rhsp;
4245 tree arg = gimple_call_arg (t, j);
4247 get_constraint_for_rhs (arg, &rhsc);
4248 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4249 while (VEC_length (ce_s, rhsc) != 0)
4251 rhsp = VEC_last (ce_s, rhsc);
4252 process_constraint (new_constraint (lhs, *rhsp));
4253 VEC_pop (ce_s, rhsc);
4257 /* If we are returning a value, assign it to the result. */
4258 lhsop = gimple_call_lhs (t);
4261 struct constraint_expr rhs;
4262 struct constraint_expr *lhsp;
4264 get_constraint_for (lhsop, &lhsc);
4265 rhs = get_function_part_constraint (fi, fi_result);
4267 && DECL_RESULT (fndecl)
4268 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4270 VEC(ce_s, heap) *tem = NULL;
4271 VEC_safe_push (ce_s, heap, tem, &rhs);
4273 rhs = *VEC_index (ce_s, tem, 0);
4274 VEC_free(ce_s, heap, tem);
4276 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4277 process_constraint (new_constraint (*lhsp, rhs));
4280 /* If we pass the result decl by reference, honor that. */
4283 && DECL_RESULT (fndecl)
4284 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4286 struct constraint_expr lhs;
4287 struct constraint_expr *rhsp;
4289 get_constraint_for_address_of (lhsop, &rhsc);
4290 lhs = get_function_part_constraint (fi, fi_result);
4291 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4292 process_constraint (new_constraint (lhs, *rhsp));
4293 VEC_free (ce_s, heap, rhsc);
4296 /* If we use a static chain, pass it along. */
4297 if (gimple_call_chain (t))
4299 struct constraint_expr lhs;
4300 struct constraint_expr *rhsp;
4302 get_constraint_for (gimple_call_chain (t), &rhsc);
4303 lhs = get_function_part_constraint (fi, fi_static_chain);
4304 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4305 process_constraint (new_constraint (lhs, *rhsp));
4310 /* Walk statement T setting up aliasing constraints according to the
4311 references found in T. This function is the main part of the
4312 constraint builder. AI points to auxiliary alias information used
4313 when building alias sets and computing alias grouping heuristics. */
4316 find_func_aliases (gimple origt)
4319 VEC(ce_s, heap) *lhsc = NULL;
4320 VEC(ce_s, heap) *rhsc = NULL;
4321 struct constraint_expr *c;
4324 /* Now build constraints expressions. */
4325 if (gimple_code (t) == GIMPLE_PHI)
4330 /* For a phi node, assign all the arguments to
4332 get_constraint_for (gimple_phi_result (t), &lhsc);
4333 for (i = 0; i < gimple_phi_num_args (t); i++)
4335 tree strippedrhs = PHI_ARG_DEF (t, i);
4337 STRIP_NOPS (strippedrhs);
4338 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4340 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4342 struct constraint_expr *c2;
4343 while (VEC_length (ce_s, rhsc) > 0)
4345 c2 = VEC_last (ce_s, rhsc);
4346 process_constraint (new_constraint (*c, *c2));
4347 VEC_pop (ce_s, rhsc);
4352 /* In IPA mode, we need to generate constraints to pass call
4353 arguments through their calls. There are two cases,
4354 either a GIMPLE_CALL returning a value, or just a plain
4355 GIMPLE_CALL when we are not.
4357 In non-ipa mode, we need to generate constraints for each
4358 pointer passed by address. */
4359 else if (is_gimple_call (t))
4360 find_func_aliases_for_call (t);
4362 /* Otherwise, just a regular assignment statement. Only care about
4363 operations with pointer result, others are dealt with as escape
4364 points if they have pointer operands. */
4365 else if (is_gimple_assign (t))
4367 /* Otherwise, just a regular assignment statement. */
4368 tree lhsop = gimple_assign_lhs (t);
4369 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4371 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4372 do_structure_copy (lhsop, rhsop);
4375 enum tree_code code = gimple_assign_rhs_code (t);
4377 get_constraint_for (lhsop, &lhsc);
4379 if (code == POINTER_PLUS_EXPR)
4380 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4381 gimple_assign_rhs2 (t), &rhsc);
4382 else if (code == BIT_AND_EXPR
4383 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4385 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4386 the pointer. Handle it by offsetting it by UNKNOWN. */
4387 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4390 else if ((CONVERT_EXPR_CODE_P (code)
4391 && !(POINTER_TYPE_P (gimple_expr_type (t))
4392 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4393 || gimple_assign_single_p (t))
4394 get_constraint_for_rhs (rhsop, &rhsc);
4395 else if (truth_value_p (code))
4396 /* Truth value results are not pointer (parts). Or at least
4397 very very unreasonable obfuscation of a part. */
4401 /* All other operations are merges. */
4402 VEC (ce_s, heap) *tmp = NULL;
4403 struct constraint_expr *rhsp;
4405 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4406 for (i = 2; i < gimple_num_ops (t); ++i)
4408 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4409 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4410 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4411 VEC_truncate (ce_s, tmp, 0);
4413 VEC_free (ce_s, heap, tmp);
4415 process_all_all_constraints (lhsc, rhsc);
4417 /* If there is a store to a global variable the rhs escapes. */
4418 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4420 && is_global_var (lhsop)
4422 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4423 make_escape_constraint (rhsop);
4424 /* If this is a conversion of a non-restrict pointer to a
4425 restrict pointer track it with a new heapvar. */
4426 else if (gimple_assign_cast_p (t)
4427 && POINTER_TYPE_P (TREE_TYPE (rhsop))
4428 && POINTER_TYPE_P (TREE_TYPE (lhsop))
4429 && !TYPE_RESTRICT (TREE_TYPE (rhsop))
4430 && TYPE_RESTRICT (TREE_TYPE (lhsop)))
4431 make_constraint_from_restrict (get_vi_for_tree (lhsop),
4434 /* Handle escapes through return. */
4435 else if (gimple_code (t) == GIMPLE_RETURN
4436 && gimple_return_retval (t) != NULL_TREE)
4440 || !(fi = get_vi_for_tree (cfun->decl)))
4441 make_escape_constraint (gimple_return_retval (t));
4442 else if (in_ipa_mode
4445 struct constraint_expr lhs ;
4446 struct constraint_expr *rhsp;
4449 lhs = get_function_part_constraint (fi, fi_result);
4450 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4451 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4452 process_constraint (new_constraint (lhs, *rhsp));
4455 /* Handle asms conservatively by adding escape constraints to everything. */
4456 else if (gimple_code (t) == GIMPLE_ASM)
4458 unsigned i, noutputs;
4459 const char **oconstraints;
4460 const char *constraint;
4461 bool allows_mem, allows_reg, is_inout;
4463 noutputs = gimple_asm_noutputs (t);
4464 oconstraints = XALLOCAVEC (const char *, noutputs);
4466 for (i = 0; i < noutputs; ++i)
4468 tree link = gimple_asm_output_op (t, i);
4469 tree op = TREE_VALUE (link);
4471 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4472 oconstraints[i] = constraint;
4473 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4474 &allows_reg, &is_inout);
4476 /* A memory constraint makes the address of the operand escape. */
4477 if (!allows_reg && allows_mem)
4478 make_escape_constraint (build_fold_addr_expr (op));
4480 /* The asm may read global memory, so outputs may point to
4481 any global memory. */
4484 VEC(ce_s, heap) *lhsc = NULL;
4485 struct constraint_expr rhsc, *lhsp;
4487 get_constraint_for (op, &lhsc);
4488 rhsc.var = nonlocal_id;
4491 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4492 process_constraint (new_constraint (*lhsp, rhsc));
4493 VEC_free (ce_s, heap, lhsc);
4496 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4498 tree link = gimple_asm_input_op (t, i);
4499 tree op = TREE_VALUE (link);
4501 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4503 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4504 &allows_mem, &allows_reg);
4506 /* A memory constraint makes the address of the operand escape. */
4507 if (!allows_reg && allows_mem)
4508 make_escape_constraint (build_fold_addr_expr (op));
4509 /* Strictly we'd only need the constraint to ESCAPED if
4510 the asm clobbers memory, otherwise using something
4511 along the lines of per-call clobbers/uses would be enough. */
4513 make_escape_constraint (op);
4517 VEC_free (ce_s, heap, rhsc);
4518 VEC_free (ce_s, heap, lhsc);
4522 /* Create a constraint adding to the clobber set of FI the memory
4523 pointed to by PTR. */
4526 process_ipa_clobber (varinfo_t fi, tree ptr)
4528 VEC(ce_s, heap) *ptrc = NULL;
4529 struct constraint_expr *c, lhs;
4531 get_constraint_for_rhs (ptr, &ptrc);
4532 lhs = get_function_part_constraint (fi, fi_clobbers);
4533 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4534 process_constraint (new_constraint (lhs, *c));
4535 VEC_free (ce_s, heap, ptrc);
4538 /* Walk statement T setting up clobber and use constraints according to the
4539 references found in T. This function is a main part of the
4540 IPA constraint builder. */
4543 find_func_clobbers (gimple origt)
4546 VEC(ce_s, heap) *lhsc = NULL;
4547 VEC(ce_s, heap) *rhsc = NULL;
4550 /* Add constraints for clobbered/used in IPA mode.
4551 We are not interested in what automatic variables are clobbered
4552 or used as we only use the information in the caller to which
4553 they do not escape. */
4554 gcc_assert (in_ipa_mode);
4556 /* If the stmt refers to memory in any way it better had a VUSE. */
4557 if (gimple_vuse (t) == NULL_TREE)
4560 /* We'd better have function information for the current function. */
4561 fi = lookup_vi_for_tree (cfun->decl);
4562 gcc_assert (fi != NULL);
4564 /* Account for stores in assignments and calls. */
4565 if (gimple_vdef (t) != NULL_TREE
4566 && gimple_has_lhs (t))
4568 tree lhs = gimple_get_lhs (t);
4570 while (handled_component_p (tem))
4571 tem = TREE_OPERAND (tem, 0);
4573 && !auto_var_in_fn_p (tem, cfun->decl))
4574 || INDIRECT_REF_P (tem)
4575 || (TREE_CODE (tem) == MEM_REF
4576 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4578 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4580 struct constraint_expr lhsc, *rhsp;
4582 lhsc = get_function_part_constraint (fi, fi_clobbers);
4583 get_constraint_for_address_of (lhs, &rhsc);
4584 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4585 process_constraint (new_constraint (lhsc, *rhsp));
4586 VEC_free (ce_s, heap, rhsc);
4590 /* Account for uses in assigments and returns. */
4591 if (gimple_assign_single_p (t)
4592 || (gimple_code (t) == GIMPLE_RETURN
4593 && gimple_return_retval (t) != NULL_TREE))
4595 tree rhs = (gimple_assign_single_p (t)
4596 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4598 while (handled_component_p (tem))
4599 tem = TREE_OPERAND (tem, 0);
4601 && !auto_var_in_fn_p (tem, cfun->decl))
4602 || INDIRECT_REF_P (tem)
4603 || (TREE_CODE (tem) == MEM_REF
4604 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4606 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4608 struct constraint_expr lhs, *rhsp;
4610 lhs = get_function_part_constraint (fi, fi_uses);
4611 get_constraint_for_address_of (rhs, &rhsc);
4612 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4613 process_constraint (new_constraint (lhs, *rhsp));
4614 VEC_free (ce_s, heap, rhsc);
4618 if (is_gimple_call (t))
4620 varinfo_t cfi = NULL;
4621 tree decl = gimple_call_fndecl (t);
4622 struct constraint_expr lhs, rhs;
4625 /* For builtins we do not have separate function info. For those
4626 we do not generate escapes for we have to generate clobbers/uses. */
4628 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4629 switch (DECL_FUNCTION_CODE (decl))
4631 /* The following functions use and clobber memory pointed to
4632 by their arguments. */
4633 case BUILT_IN_STRCPY:
4634 case BUILT_IN_STRNCPY:
4635 case BUILT_IN_BCOPY:
4636 case BUILT_IN_MEMCPY:
4637 case BUILT_IN_MEMMOVE:
4638 case BUILT_IN_MEMPCPY:
4639 case BUILT_IN_STPCPY:
4640 case BUILT_IN_STPNCPY:
4641 case BUILT_IN_STRCAT:
4642 case BUILT_IN_STRNCAT:
4644 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4645 == BUILT_IN_BCOPY ? 1 : 0));
4646 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4647 == BUILT_IN_BCOPY ? 0 : 1));
4649 struct constraint_expr *rhsp, *lhsp;
4650 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4651 lhs = get_function_part_constraint (fi, fi_clobbers);
4652 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4653 process_constraint (new_constraint (lhs, *lhsp));
4654 VEC_free (ce_s, heap, lhsc);
4655 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4656 lhs = get_function_part_constraint (fi, fi_uses);
4657 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4658 process_constraint (new_constraint (lhs, *rhsp));
4659 VEC_free (ce_s, heap, rhsc);
4662 /* The following function clobbers memory pointed to by
4664 case BUILT_IN_MEMSET:
4666 tree dest = gimple_call_arg (t, 0);
4669 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4670 lhs = get_function_part_constraint (fi, fi_clobbers);
4671 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4672 process_constraint (new_constraint (lhs, *lhsp));
4673 VEC_free (ce_s, heap, lhsc);
4676 /* The following functions clobber their second and third
4678 case BUILT_IN_SINCOS:
4679 case BUILT_IN_SINCOSF:
4680 case BUILT_IN_SINCOSL:
4682 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4683 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4686 /* The following functions clobber their second argument. */
4687 case BUILT_IN_FREXP:
4688 case BUILT_IN_FREXPF:
4689 case BUILT_IN_FREXPL:
4690 case BUILT_IN_LGAMMA_R:
4691 case BUILT_IN_LGAMMAF_R:
4692 case BUILT_IN_LGAMMAL_R:
4693 case BUILT_IN_GAMMA_R:
4694 case BUILT_IN_GAMMAF_R:
4695 case BUILT_IN_GAMMAL_R:
4697 case BUILT_IN_MODFF:
4698 case BUILT_IN_MODFL:
4700 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4703 /* The following functions clobber their third argument. */
4704 case BUILT_IN_REMQUO:
4705 case BUILT_IN_REMQUOF:
4706 case BUILT_IN_REMQUOL:
4708 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4711 /* The following functions neither read nor clobber memory. */
4714 /* Trampolines are of no interest to us. */
4715 case BUILT_IN_INIT_TRAMPOLINE:
4716 case BUILT_IN_ADJUST_TRAMPOLINE:
4718 case BUILT_IN_VA_START:
4719 case BUILT_IN_VA_END:
4721 /* printf-style functions may have hooks to set pointers to
4722 point to somewhere into the generated string. Leave them
4723 for a later excercise... */
4725 /* Fallthru to general call handling. */;
4728 /* Parameters passed by value are used. */
4729 lhs = get_function_part_constraint (fi, fi_uses);
4730 for (i = 0; i < gimple_call_num_args (t); i++)
4732 struct constraint_expr *rhsp;
4733 tree arg = gimple_call_arg (t, i);
4735 if (TREE_CODE (arg) == SSA_NAME
4736 || is_gimple_min_invariant (arg))
4739 get_constraint_for_address_of (arg, &rhsc);
4740 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4741 process_constraint (new_constraint (lhs, *rhsp));
4742 VEC_free (ce_s, heap, rhsc);
4745 /* Build constraints for propagating clobbers/uses along the
4747 cfi = get_fi_for_callee (t);
4748 if (cfi->id == anything_id)
4750 if (gimple_vdef (t))
4751 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4753 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4758 /* For callees without function info (that's external functions),
4759 ESCAPED is clobbered and used. */
4760 if (gimple_call_fndecl (t)
4761 && !cfi->is_fn_info)
4765 if (gimple_vdef (t))
4766 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4768 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4770 /* Also honor the call statement use/clobber info. */
4771 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4772 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4774 if ((vi = lookup_call_use_vi (t)) != NULL)
4775 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4780 /* Otherwise the caller clobbers and uses what the callee does.
4781 ??? This should use a new complex constraint that filters
4782 local variables of the callee. */
4783 if (gimple_vdef (t))
4785 lhs = get_function_part_constraint (fi, fi_clobbers);
4786 rhs = get_function_part_constraint (cfi, fi_clobbers);
4787 process_constraint (new_constraint (lhs, rhs));
4789 lhs = get_function_part_constraint (fi, fi_uses);
4790 rhs = get_function_part_constraint (cfi, fi_uses);
4791 process_constraint (new_constraint (lhs, rhs));
4793 else if (gimple_code (t) == GIMPLE_ASM)
4795 /* ??? Ick. We can do better. */
4796 if (gimple_vdef (t))
4797 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4799 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4803 VEC_free (ce_s, heap, rhsc);
4807 /* Find the first varinfo in the same variable as START that overlaps with
4808 OFFSET. Return NULL if we can't find one. */
4811 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4813 /* If the offset is outside of the variable, bail out. */
4814 if (offset >= start->fullsize)
4817 /* If we cannot reach offset from start, lookup the first field
4818 and start from there. */
4819 if (start->offset > offset)
4820 start = lookup_vi_for_tree (start->decl);
4824 /* We may not find a variable in the field list with the actual
4825 offset when when we have glommed a structure to a variable.
4826 In that case, however, offset should still be within the size
4828 if (offset >= start->offset
4829 && (offset - start->offset) < start->size)
4838 /* Find the first varinfo in the same variable as START that overlaps with
4839 OFFSET. If there is no such varinfo the varinfo directly preceding
4840 OFFSET is returned. */
4843 first_or_preceding_vi_for_offset (varinfo_t start,
4844 unsigned HOST_WIDE_INT offset)
4846 /* If we cannot reach offset from start, lookup the first field
4847 and start from there. */
4848 if (start->offset > offset)
4849 start = lookup_vi_for_tree (start->decl);
4851 /* We may not find a variable in the field list with the actual
4852 offset when when we have glommed a structure to a variable.
4853 In that case, however, offset should still be within the size
4855 If we got beyond the offset we look for return the field
4856 directly preceding offset which may be the last field. */
4858 && offset >= start->offset
4859 && !((offset - start->offset) < start->size))
4860 start = start->next;
4866 /* This structure is used during pushing fields onto the fieldstack
4867 to track the offset of the field, since bitpos_of_field gives it
4868 relative to its immediate containing type, and we want it relative
4869 to the ultimate containing object. */
4873 /* Offset from the base of the base containing object to this field. */
4874 HOST_WIDE_INT offset;
4876 /* Size, in bits, of the field. */
4877 unsigned HOST_WIDE_INT size;
4879 unsigned has_unknown_size : 1;
4881 unsigned must_have_pointers : 1;
4883 unsigned may_have_pointers : 1;
4885 unsigned only_restrict_pointers : 1;
4887 typedef struct fieldoff fieldoff_s;
4889 DEF_VEC_O(fieldoff_s);
4890 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4892 /* qsort comparison function for two fieldoff's PA and PB */
4895 fieldoff_compare (const void *pa, const void *pb)
4897 const fieldoff_s *foa = (const fieldoff_s *)pa;
4898 const fieldoff_s *fob = (const fieldoff_s *)pb;
4899 unsigned HOST_WIDE_INT foasize, fobsize;
4901 if (foa->offset < fob->offset)
4903 else if (foa->offset > fob->offset)
4906 foasize = foa->size;
4907 fobsize = fob->size;
4908 if (foasize < fobsize)
4910 else if (foasize > fobsize)
4915 /* Sort a fieldstack according to the field offset and sizes. */
4917 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4919 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
4922 /* Return true if V is a tree that we can have subvars for.
4923 Normally, this is any aggregate type. Also complex
4924 types which are not gimple registers can have subvars. */
4927 var_can_have_subvars (const_tree v)
4929 /* Volatile variables should never have subvars. */
4930 if (TREE_THIS_VOLATILE (v))
4933 /* Non decls or memory tags can never have subvars. */
4937 /* Aggregates without overlapping fields can have subvars. */
4938 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
4944 /* Return true if T is a type that does contain pointers. */
4947 type_must_have_pointers (tree type)
4949 if (POINTER_TYPE_P (type))
4952 if (TREE_CODE (type) == ARRAY_TYPE)
4953 return type_must_have_pointers (TREE_TYPE (type));
4955 /* A function or method can have pointers as arguments, so track
4956 those separately. */
4957 if (TREE_CODE (type) == FUNCTION_TYPE
4958 || TREE_CODE (type) == METHOD_TYPE)
4965 field_must_have_pointers (tree t)
4967 return type_must_have_pointers (TREE_TYPE (t));
4970 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4971 the fields of TYPE onto fieldstack, recording their offsets along
4974 OFFSET is used to keep track of the offset in this entire
4975 structure, rather than just the immediately containing structure.
4976 Returns false if the caller is supposed to handle the field we
4980 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
4981 HOST_WIDE_INT offset)
4984 bool empty_p = true;
4986 if (TREE_CODE (type) != RECORD_TYPE)
4989 /* If the vector of fields is growing too big, bail out early.
4990 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4992 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
4995 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
4996 if (TREE_CODE (field) == FIELD_DECL)
4999 HOST_WIDE_INT foff = bitpos_of_field (field);
5001 if (!var_can_have_subvars (field)
5002 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5003 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5005 else if (!push_fields_onto_fieldstack
5006 (TREE_TYPE (field), fieldstack, offset + foff)
5007 && (DECL_SIZE (field)
5008 && !integer_zerop (DECL_SIZE (field))))
5009 /* Empty structures may have actual size, like in C++. So
5010 see if we didn't push any subfields and the size is
5011 nonzero, push the field onto the stack. */
5016 fieldoff_s *pair = NULL;
5017 bool has_unknown_size = false;
5018 bool must_have_pointers_p;
5020 if (!VEC_empty (fieldoff_s, *fieldstack))
5021 pair = VEC_last (fieldoff_s, *fieldstack);
5023 /* If there isn't anything at offset zero, create sth. */
5025 && offset + foff != 0)
5027 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5029 pair->size = offset + foff;
5030 pair->has_unknown_size = false;
5031 pair->must_have_pointers = false;
5032 pair->may_have_pointers = false;
5033 pair->only_restrict_pointers = false;
5036 if (!DECL_SIZE (field)
5037 || !host_integerp (DECL_SIZE (field), 1))
5038 has_unknown_size = true;
5040 /* If adjacent fields do not contain pointers merge them. */
5041 must_have_pointers_p = field_must_have_pointers (field);
5043 && !has_unknown_size
5044 && !must_have_pointers_p
5045 && !pair->must_have_pointers
5046 && !pair->has_unknown_size
5047 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5049 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5053 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5054 pair->offset = offset + foff;
5055 pair->has_unknown_size = has_unknown_size;
5056 if (!has_unknown_size)
5057 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5060 pair->must_have_pointers = must_have_pointers_p;
5061 pair->may_have_pointers = true;
5062 pair->only_restrict_pointers
5063 = (!has_unknown_size
5064 && POINTER_TYPE_P (TREE_TYPE (field))
5065 && TYPE_RESTRICT (TREE_TYPE (field)));
5075 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5076 if it is a varargs function. */
5079 count_num_arguments (tree decl, bool *is_varargs)
5081 unsigned int num = 0;
5084 /* Capture named arguments for K&R functions. They do not
5085 have a prototype and thus no TYPE_ARG_TYPES. */
5086 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5089 /* Check if the function has variadic arguments. */
5090 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5091 if (TREE_VALUE (t) == void_type_node)
5099 /* Creation function node for DECL, using NAME, and return the index
5100 of the variable we've created for the function. */
5103 create_function_info_for (tree decl, const char *name)
5105 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5106 varinfo_t vi, prev_vi;
5109 bool is_varargs = false;
5110 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5112 /* Create the variable info. */
5114 vi = new_var_info (decl, name);
5117 vi->fullsize = fi_parm_base + num_args;
5119 vi->may_have_pointers = false;
5122 insert_vi_for_tree (vi->decl, vi);
5126 /* Create a variable for things the function clobbers and one for
5127 things the function uses. */
5129 varinfo_t clobbervi, usevi;
5130 const char *newname;
5133 asprintf (&tempname, "%s.clobber", name);
5134 newname = ggc_strdup (tempname);
5137 clobbervi = new_var_info (NULL, newname);
5138 clobbervi->offset = fi_clobbers;
5139 clobbervi->size = 1;
5140 clobbervi->fullsize = vi->fullsize;
5141 clobbervi->is_full_var = true;
5142 clobbervi->is_global_var = false;
5143 gcc_assert (prev_vi->offset < clobbervi->offset);
5144 prev_vi->next = clobbervi;
5145 prev_vi = clobbervi;
5147 asprintf (&tempname, "%s.use", name);
5148 newname = ggc_strdup (tempname);
5151 usevi = new_var_info (NULL, newname);
5152 usevi->offset = fi_uses;
5154 usevi->fullsize = vi->fullsize;
5155 usevi->is_full_var = true;
5156 usevi->is_global_var = false;
5157 gcc_assert (prev_vi->offset < usevi->offset);
5158 prev_vi->next = usevi;
5162 /* And one for the static chain. */
5163 if (fn->static_chain_decl != NULL_TREE)
5166 const char *newname;
5169 asprintf (&tempname, "%s.chain", name);
5170 newname = ggc_strdup (tempname);
5173 chainvi = new_var_info (fn->static_chain_decl, newname);
5174 chainvi->offset = fi_static_chain;
5176 chainvi->fullsize = vi->fullsize;
5177 chainvi->is_full_var = true;
5178 chainvi->is_global_var = false;
5179 gcc_assert (prev_vi->offset < chainvi->offset);
5180 prev_vi->next = chainvi;
5182 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5185 /* Create a variable for the return var. */
5186 if (DECL_RESULT (decl) != NULL
5187 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5190 const char *newname;
5192 tree resultdecl = decl;
5194 if (DECL_RESULT (decl))
5195 resultdecl = DECL_RESULT (decl);
5197 asprintf (&tempname, "%s.result", name);
5198 newname = ggc_strdup (tempname);
5201 resultvi = new_var_info (resultdecl, newname);
5202 resultvi->offset = fi_result;
5204 resultvi->fullsize = vi->fullsize;
5205 resultvi->is_full_var = true;
5206 if (DECL_RESULT (decl))
5207 resultvi->may_have_pointers = true;
5208 gcc_assert (prev_vi->offset < resultvi->offset);
5209 prev_vi->next = resultvi;
5211 if (DECL_RESULT (decl))
5212 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5215 /* Set up variables for each argument. */
5216 arg = DECL_ARGUMENTS (decl);
5217 for (i = 0; i < num_args; i++)
5220 const char *newname;
5222 tree argdecl = decl;
5227 asprintf (&tempname, "%s.arg%d", name, i);
5228 newname = ggc_strdup (tempname);
5231 argvi = new_var_info (argdecl, newname);
5232 argvi->offset = fi_parm_base + i;
5234 argvi->is_full_var = true;
5235 argvi->fullsize = vi->fullsize;
5237 argvi->may_have_pointers = true;
5238 gcc_assert (prev_vi->offset < argvi->offset);
5239 prev_vi->next = argvi;
5243 insert_vi_for_tree (arg, argvi);
5244 arg = DECL_CHAIN (arg);
5248 /* Add one representative for all further args. */
5252 const char *newname;
5256 asprintf (&tempname, "%s.varargs", name);
5257 newname = ggc_strdup (tempname);
5260 /* We need sth that can be pointed to for va_start. */
5261 decl = build_fake_var_decl (ptr_type_node);
5263 argvi = new_var_info (decl, newname);
5264 argvi->offset = fi_parm_base + num_args;
5266 argvi->is_full_var = true;
5267 argvi->is_heap_var = true;
5268 argvi->fullsize = vi->fullsize;
5269 gcc_assert (prev_vi->offset < argvi->offset);
5270 prev_vi->next = argvi;
5278 /* Return true if FIELDSTACK contains fields that overlap.
5279 FIELDSTACK is assumed to be sorted by offset. */
5282 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5284 fieldoff_s *fo = NULL;
5286 HOST_WIDE_INT lastoffset = -1;
5288 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5290 if (fo->offset == lastoffset)
5292 lastoffset = fo->offset;
5297 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5298 This will also create any varinfo structures necessary for fields
5302 create_variable_info_for_1 (tree decl, const char *name)
5304 varinfo_t vi, newvi;
5305 tree decl_type = TREE_TYPE (decl);
5306 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5307 VEC (fieldoff_s,heap) *fieldstack = NULL;
5312 || !host_integerp (declsize, 1))
5314 vi = new_var_info (decl, name);
5318 vi->is_unknown_size_var = true;
5319 vi->is_full_var = true;
5320 vi->may_have_pointers = true;
5324 /* Collect field information. */
5325 if (use_field_sensitive
5326 && var_can_have_subvars (decl)
5327 /* ??? Force us to not use subfields for global initializers
5328 in IPA mode. Else we'd have to parse arbitrary initializers. */
5330 && is_global_var (decl)
5331 && DECL_INITIAL (decl)))
5333 fieldoff_s *fo = NULL;
5334 bool notokay = false;
5337 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5339 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5340 if (fo->has_unknown_size
5347 /* We can't sort them if we have a field with a variable sized type,
5348 which will make notokay = true. In that case, we are going to return
5349 without creating varinfos for the fields anyway, so sorting them is a
5353 sort_fieldstack (fieldstack);
5354 /* Due to some C++ FE issues, like PR 22488, we might end up
5355 what appear to be overlapping fields even though they,
5356 in reality, do not overlap. Until the C++ FE is fixed,
5357 we will simply disable field-sensitivity for these cases. */
5358 notokay = check_for_overlaps (fieldstack);
5362 VEC_free (fieldoff_s, heap, fieldstack);
5365 /* If we didn't end up collecting sub-variables create a full
5366 variable for the decl. */
5367 if (VEC_length (fieldoff_s, fieldstack) <= 1
5368 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5370 vi = new_var_info (decl, name);
5372 vi->may_have_pointers = true;
5373 vi->fullsize = TREE_INT_CST_LOW (declsize);
5374 vi->size = vi->fullsize;
5375 vi->is_full_var = true;
5376 VEC_free (fieldoff_s, heap, fieldstack);
5380 vi = new_var_info (decl, name);
5381 vi->fullsize = TREE_INT_CST_LOW (declsize);
5382 for (i = 0, newvi = vi;
5383 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5384 ++i, newvi = newvi->next)
5386 const char *newname = "NULL";
5391 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5392 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5393 newname = ggc_strdup (tempname);
5396 newvi->name = newname;
5397 newvi->offset = fo->offset;
5398 newvi->size = fo->size;
5399 newvi->fullsize = vi->fullsize;
5400 newvi->may_have_pointers = fo->may_have_pointers;
5401 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5402 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5403 newvi->next = new_var_info (decl, name);
5406 VEC_free (fieldoff_s, heap, fieldstack);
5412 create_variable_info_for (tree decl, const char *name)
5414 varinfo_t vi = create_variable_info_for_1 (decl, name);
5415 unsigned int id = vi->id;
5417 insert_vi_for_tree (decl, vi);
5419 /* Create initial constraints for globals. */
5420 for (; vi; vi = vi->next)
5422 if (!vi->may_have_pointers
5423 || !vi->is_global_var)
5426 /* Mark global restrict qualified pointers. */
5427 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5428 && TYPE_RESTRICT (TREE_TYPE (decl)))
5429 || vi->only_restrict_pointers)
5430 make_constraint_from_restrict (vi, "GLOBAL_RESTRICT");
5432 /* For escaped variables initialize them from nonlocal. */
5434 || DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5435 make_copy_constraint (vi, nonlocal_id);
5437 /* If this is a global variable with an initializer and we are in
5438 IPA mode generate constraints for it. In non-IPA mode
5439 the initializer from nonlocal is all we need. */
5441 && DECL_INITIAL (decl))
5443 VEC (ce_s, heap) *rhsc = NULL;
5444 struct constraint_expr lhs, *rhsp;
5446 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5450 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5451 process_constraint (new_constraint (lhs, *rhsp));
5452 /* If this is a variable that escapes from the unit
5453 the initializer escapes as well. */
5454 if (DECL_EXTERNAL (decl) || TREE_PUBLIC (decl))
5456 lhs.var = escaped_id;
5459 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5460 process_constraint (new_constraint (lhs, *rhsp));
5462 VEC_free (ce_s, heap, rhsc);
5469 /* Print out the points-to solution for VAR to FILE. */
5472 dump_solution_for_var (FILE *file, unsigned int var)
5474 varinfo_t vi = get_varinfo (var);
5478 /* Dump the solution for unified vars anyway, this avoids difficulties
5479 in scanning dumps in the testsuite. */
5480 fprintf (file, "%s = { ", vi->name);
5481 vi = get_varinfo (find (var));
5482 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5483 fprintf (file, "%s ", get_varinfo (i)->name);
5484 fprintf (file, "}");
5486 /* But note when the variable was unified. */
5488 fprintf (file, " same as %s", vi->name);
5490 fprintf (file, "\n");
5493 /* Print the points-to solution for VAR to stdout. */
5496 debug_solution_for_var (unsigned int var)
5498 dump_solution_for_var (stdout, var);
5501 /* Create varinfo structures for all of the variables in the
5502 function for intraprocedural mode. */
5505 intra_create_variable_infos (void)
5509 /* For each incoming pointer argument arg, create the constraint ARG
5510 = NONLOCAL or a dummy variable if it is a restrict qualified
5511 passed-by-reference argument. */
5512 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5516 /* For restrict qualified pointers to objects passed by
5517 reference build a real representative for the pointed-to object. */
5518 if (DECL_BY_REFERENCE (t)
5519 && POINTER_TYPE_P (TREE_TYPE (t))
5520 && TYPE_RESTRICT (TREE_TYPE (t)))
5522 struct constraint_expr lhsc, rhsc;
5524 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t)));
5525 DECL_EXTERNAL (heapvar) = 1;
5526 vi = get_varinfo (create_variable_info_for (heapvar, "PARM_NOALIAS"));
5527 lhsc.var = get_vi_for_tree (t)->id;
5531 rhsc.type = ADDRESSOF;
5533 process_constraint (new_constraint (lhsc, rhsc));
5534 vi->is_restrict_var = 1;
5538 for (p = get_vi_for_tree (t); p; p = p->next)
5540 if (p->may_have_pointers)
5541 make_constraint_from (p, nonlocal_id);
5542 if (p->only_restrict_pointers)
5543 make_constraint_from_restrict (p, "PARM_RESTRICT");
5545 if (POINTER_TYPE_P (TREE_TYPE (t))
5546 && TYPE_RESTRICT (TREE_TYPE (t)))
5547 make_constraint_from_restrict (get_vi_for_tree (t), "PARM_RESTRICT");
5550 /* Add a constraint for a result decl that is passed by reference. */
5551 if (DECL_RESULT (cfun->decl)
5552 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5554 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5556 for (p = result_vi; p; p = p->next)
5557 make_constraint_from (p, nonlocal_id);
5560 /* Add a constraint for the incoming static chain parameter. */
5561 if (cfun->static_chain_decl != NULL_TREE)
5563 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5565 for (p = chain_vi; p; p = p->next)
5566 make_constraint_from (p, nonlocal_id);
5570 /* Structure used to put solution bitmaps in a hashtable so they can
5571 be shared among variables with the same points-to set. */
5573 typedef struct shared_bitmap_info
5577 } *shared_bitmap_info_t;
5578 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5580 static htab_t shared_bitmap_table;
5582 /* Hash function for a shared_bitmap_info_t */
5585 shared_bitmap_hash (const void *p)
5587 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5588 return bi->hashcode;
5591 /* Equality function for two shared_bitmap_info_t's. */
5594 shared_bitmap_eq (const void *p1, const void *p2)
5596 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5597 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5598 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5601 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5602 existing instance if there is one, NULL otherwise. */
5605 shared_bitmap_lookup (bitmap pt_vars)
5608 struct shared_bitmap_info sbi;
5610 sbi.pt_vars = pt_vars;
5611 sbi.hashcode = bitmap_hash (pt_vars);
5613 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5614 sbi.hashcode, NO_INSERT);
5618 return ((shared_bitmap_info_t) *slot)->pt_vars;
5622 /* Add a bitmap to the shared bitmap hashtable. */
5625 shared_bitmap_add (bitmap pt_vars)
5628 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5630 sbi->pt_vars = pt_vars;
5631 sbi->hashcode = bitmap_hash (pt_vars);
5633 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5634 sbi->hashcode, INSERT);
5635 gcc_assert (!*slot);
5636 *slot = (void *) sbi;
5640 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5643 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5648 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5650 varinfo_t vi = get_varinfo (i);
5652 /* The only artificial variables that are allowed in a may-alias
5653 set are heap variables. */
5654 if (vi->is_artificial_var && !vi->is_heap_var)
5657 if (TREE_CODE (vi->decl) == VAR_DECL
5658 || TREE_CODE (vi->decl) == PARM_DECL
5659 || TREE_CODE (vi->decl) == RESULT_DECL)
5661 /* If we are in IPA mode we will not recompute points-to
5662 sets after inlining so make sure they stay valid. */
5664 && !DECL_PT_UID_SET_P (vi->decl))
5665 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5667 /* Add the decl to the points-to set. Note that the points-to
5668 set contains global variables. */
5669 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5670 if (vi->is_global_var)
5671 pt->vars_contains_global = true;
5677 /* Compute the points-to solution *PT for the variable VI. */
5680 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5684 bitmap finished_solution;
5688 memset (pt, 0, sizeof (struct pt_solution));
5690 /* This variable may have been collapsed, let's get the real
5692 vi = get_varinfo (find (orig_vi->id));
5694 /* Translate artificial variables into SSA_NAME_PTR_INFO
5696 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5698 varinfo_t vi = get_varinfo (i);
5700 if (vi->is_artificial_var)
5702 if (vi->id == nothing_id)
5704 else if (vi->id == escaped_id)
5707 pt->ipa_escaped = 1;
5711 else if (vi->id == nonlocal_id)
5713 else if (vi->is_heap_var)
5714 /* We represent heapvars in the points-to set properly. */
5716 else if (vi->id == readonly_id)
5719 else if (vi->id == anything_id
5720 || vi->id == integer_id)
5723 if (vi->is_restrict_var)
5724 pt->vars_contains_restrict = true;
5727 /* Instead of doing extra work, simply do not create
5728 elaborate points-to information for pt_anything pointers. */
5730 && (orig_vi->is_artificial_var
5731 || !pt->vars_contains_restrict))
5734 /* Share the final set of variables when possible. */
5735 finished_solution = BITMAP_GGC_ALLOC ();
5736 stats.points_to_sets_created++;
5738 set_uids_in_ptset (finished_solution, vi->solution, pt);
5739 result = shared_bitmap_lookup (finished_solution);
5742 shared_bitmap_add (finished_solution);
5743 pt->vars = finished_solution;
5748 bitmap_clear (finished_solution);
5752 /* Given a pointer variable P, fill in its points-to set. */
5755 find_what_p_points_to (tree p)
5757 struct ptr_info_def *pi;
5761 /* For parameters, get at the points-to set for the actual parm
5763 if (TREE_CODE (p) == SSA_NAME
5764 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5765 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5766 && SSA_NAME_IS_DEFAULT_DEF (p))
5767 lookup_p = SSA_NAME_VAR (p);
5769 vi = lookup_vi_for_tree (lookup_p);
5773 pi = get_ptr_info (p);
5774 find_what_var_points_to (vi, &pi->pt);
5778 /* Query statistics for points-to solutions. */
5781 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5782 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5783 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5784 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5788 dump_pta_stats (FILE *s)
5790 fprintf (s, "\nPTA query stats:\n");
5791 fprintf (s, " pt_solution_includes: "
5792 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5793 HOST_WIDE_INT_PRINT_DEC" queries\n",
5794 pta_stats.pt_solution_includes_no_alias,
5795 pta_stats.pt_solution_includes_no_alias
5796 + pta_stats.pt_solution_includes_may_alias);
5797 fprintf (s, " pt_solutions_intersect: "
5798 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5799 HOST_WIDE_INT_PRINT_DEC" queries\n",
5800 pta_stats.pt_solutions_intersect_no_alias,
5801 pta_stats.pt_solutions_intersect_no_alias
5802 + pta_stats.pt_solutions_intersect_may_alias);
5806 /* Reset the points-to solution *PT to a conservative default
5807 (point to anything). */
5810 pt_solution_reset (struct pt_solution *pt)
5812 memset (pt, 0, sizeof (struct pt_solution));
5813 pt->anything = true;
5816 /* Set the points-to solution *PT to point only to the variables
5817 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5818 global variables and VARS_CONTAINS_RESTRICT specifies whether
5819 it contains restrict tag variables. */
5822 pt_solution_set (struct pt_solution *pt, bitmap vars,
5823 bool vars_contains_global, bool vars_contains_restrict)
5825 memset (pt, 0, sizeof (struct pt_solution));
5827 pt->vars_contains_global = vars_contains_global;
5828 pt->vars_contains_restrict = vars_contains_restrict;
5831 /* Set the points-to solution *PT to point only to the variable VAR. */
5834 pt_solution_set_var (struct pt_solution *pt, tree var)
5836 memset (pt, 0, sizeof (struct pt_solution));
5837 pt->vars = BITMAP_GGC_ALLOC ();
5838 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5839 pt->vars_contains_global = is_global_var (var);
5842 /* Computes the union of the points-to solutions *DEST and *SRC and
5843 stores the result in *DEST. This changes the points-to bitmap
5844 of *DEST and thus may not be used if that might be shared.
5845 The points-to bitmap of *SRC and *DEST will not be shared after
5846 this function if they were not before. */
5849 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5851 dest->anything |= src->anything;
5854 pt_solution_reset (dest);
5858 dest->nonlocal |= src->nonlocal;
5859 dest->escaped |= src->escaped;
5860 dest->ipa_escaped |= src->ipa_escaped;
5861 dest->null |= src->null;
5862 dest->vars_contains_global |= src->vars_contains_global;
5863 dest->vars_contains_restrict |= src->vars_contains_restrict;
5868 dest->vars = BITMAP_GGC_ALLOC ();
5869 bitmap_ior_into (dest->vars, src->vars);
5872 /* Return true if the points-to solution *PT is empty. */
5875 pt_solution_empty_p (struct pt_solution *pt)
5882 && !bitmap_empty_p (pt->vars))
5885 /* If the solution includes ESCAPED, check if that is empty. */
5887 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5890 /* If the solution includes ESCAPED, check if that is empty. */
5892 && !pt_solution_empty_p (&ipa_escaped_pt))
5898 /* Return true if the points-to solution *PT includes global memory. */
5901 pt_solution_includes_global (struct pt_solution *pt)
5905 || pt->vars_contains_global)
5909 return pt_solution_includes_global (&cfun->gimple_df->escaped);
5911 if (pt->ipa_escaped)
5912 return pt_solution_includes_global (&ipa_escaped_pt);
5914 /* ??? This predicate is not correct for the IPA-PTA solution
5915 as we do not properly distinguish between unit escape points
5916 and global variables. */
5917 if (cfun->gimple_df->ipa_pta)
5923 /* Return true if the points-to solution *PT includes the variable
5924 declaration DECL. */
5927 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
5933 && is_global_var (decl))
5937 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
5940 /* If the solution includes ESCAPED, check it. */
5942 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
5945 /* If the solution includes ESCAPED, check it. */
5947 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
5954 pt_solution_includes (struct pt_solution *pt, const_tree decl)
5956 bool res = pt_solution_includes_1 (pt, decl);
5958 ++pta_stats.pt_solution_includes_may_alias;
5960 ++pta_stats.pt_solution_includes_no_alias;
5964 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5968 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
5970 if (pt1->anything || pt2->anything)
5973 /* If either points to unknown global memory and the other points to
5974 any global memory they alias. */
5977 || pt2->vars_contains_global))
5979 && pt1->vars_contains_global))
5982 /* Check the escaped solution if required. */
5983 if ((pt1->escaped || pt2->escaped)
5984 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5986 /* If both point to escaped memory and that solution
5987 is not empty they alias. */
5988 if (pt1->escaped && pt2->escaped)
5991 /* If either points to escaped memory see if the escaped solution
5992 intersects with the other. */
5994 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
5996 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6000 /* Check the escaped solution if required.
6001 ??? Do we need to check the local against the IPA escaped sets? */
6002 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6003 && !pt_solution_empty_p (&ipa_escaped_pt))
6005 /* If both point to escaped memory and that solution
6006 is not empty they alias. */
6007 if (pt1->ipa_escaped && pt2->ipa_escaped)
6010 /* If either points to escaped memory see if the escaped solution
6011 intersects with the other. */
6012 if ((pt1->ipa_escaped
6013 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6014 || (pt2->ipa_escaped
6015 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6019 /* Now both pointers alias if their points-to solution intersects. */
6022 && bitmap_intersect_p (pt1->vars, pt2->vars));
6026 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6028 bool res = pt_solutions_intersect_1 (pt1, pt2);
6030 ++pta_stats.pt_solutions_intersect_may_alias;
6032 ++pta_stats.pt_solutions_intersect_no_alias;
6036 /* Return true if both points-to solutions PT1 and PT2 for two restrict
6037 qualified pointers are possibly based on the same pointer. */
6040 pt_solutions_same_restrict_base (struct pt_solution *pt1,
6041 struct pt_solution *pt2)
6043 /* If we deal with points-to solutions of two restrict qualified
6044 pointers solely rely on the pointed-to variable bitmap intersection.
6045 For two pointers that are based on each other the bitmaps will
6047 if (pt1->vars_contains_restrict
6048 && pt2->vars_contains_restrict)
6050 gcc_assert (pt1->vars && pt2->vars);
6051 return bitmap_intersect_p (pt1->vars, pt2->vars);
6058 /* Dump points-to information to OUTFILE. */
6061 dump_sa_points_to_info (FILE *outfile)
6065 fprintf (outfile, "\nPoints-to sets\n\n");
6067 if (dump_flags & TDF_STATS)
6069 fprintf (outfile, "Stats:\n");
6070 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6071 fprintf (outfile, "Non-pointer vars: %d\n",
6072 stats.nonpointer_vars);
6073 fprintf (outfile, "Statically unified vars: %d\n",
6074 stats.unified_vars_static);
6075 fprintf (outfile, "Dynamically unified vars: %d\n",
6076 stats.unified_vars_dynamic);
6077 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6078 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6079 fprintf (outfile, "Number of implicit edges: %d\n",
6080 stats.num_implicit_edges);
6083 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6085 varinfo_t vi = get_varinfo (i);
6086 if (!vi->may_have_pointers)
6088 dump_solution_for_var (outfile, i);
6093 /* Debug points-to information to stderr. */
6096 debug_sa_points_to_info (void)
6098 dump_sa_points_to_info (stderr);
6102 /* Initialize the always-existing constraint variables for NULL
6103 ANYTHING, READONLY, and INTEGER */
6106 init_base_vars (void)
6108 struct constraint_expr lhs, rhs;
6109 varinfo_t var_anything;
6110 varinfo_t var_nothing;
6111 varinfo_t var_readonly;
6112 varinfo_t var_escaped;
6113 varinfo_t var_nonlocal;
6114 varinfo_t var_storedanything;
6115 varinfo_t var_integer;
6117 /* Create the NULL variable, used to represent that a variable points
6119 var_nothing = new_var_info (NULL_TREE, "NULL");
6120 gcc_assert (var_nothing->id == nothing_id);
6121 var_nothing->is_artificial_var = 1;
6122 var_nothing->offset = 0;
6123 var_nothing->size = ~0;
6124 var_nothing->fullsize = ~0;
6125 var_nothing->is_special_var = 1;
6126 var_nothing->may_have_pointers = 0;
6127 var_nothing->is_global_var = 0;
6129 /* Create the ANYTHING variable, used to represent that a variable
6130 points to some unknown piece of memory. */
6131 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6132 gcc_assert (var_anything->id == anything_id);
6133 var_anything->is_artificial_var = 1;
6134 var_anything->size = ~0;
6135 var_anything->offset = 0;
6136 var_anything->next = NULL;
6137 var_anything->fullsize = ~0;
6138 var_anything->is_special_var = 1;
6140 /* Anything points to anything. This makes deref constraints just
6141 work in the presence of linked list and other p = *p type loops,
6142 by saying that *ANYTHING = ANYTHING. */
6144 lhs.var = anything_id;
6146 rhs.type = ADDRESSOF;
6147 rhs.var = anything_id;
6150 /* This specifically does not use process_constraint because
6151 process_constraint ignores all anything = anything constraints, since all
6152 but this one are redundant. */
6153 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6155 /* Create the READONLY variable, used to represent that a variable
6156 points to readonly memory. */
6157 var_readonly = new_var_info (NULL_TREE, "READONLY");
6158 gcc_assert (var_readonly->id == readonly_id);
6159 var_readonly->is_artificial_var = 1;
6160 var_readonly->offset = 0;
6161 var_readonly->size = ~0;
6162 var_readonly->fullsize = ~0;
6163 var_readonly->next = NULL;
6164 var_readonly->is_special_var = 1;
6166 /* readonly memory points to anything, in order to make deref
6167 easier. In reality, it points to anything the particular
6168 readonly variable can point to, but we don't track this
6171 lhs.var = readonly_id;
6173 rhs.type = ADDRESSOF;
6174 rhs.var = readonly_id; /* FIXME */
6176 process_constraint (new_constraint (lhs, rhs));
6178 /* Create the ESCAPED variable, used to represent the set of escaped
6180 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6181 gcc_assert (var_escaped->id == escaped_id);
6182 var_escaped->is_artificial_var = 1;
6183 var_escaped->offset = 0;
6184 var_escaped->size = ~0;
6185 var_escaped->fullsize = ~0;
6186 var_escaped->is_special_var = 0;
6188 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6190 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6191 gcc_assert (var_nonlocal->id == nonlocal_id);
6192 var_nonlocal->is_artificial_var = 1;
6193 var_nonlocal->offset = 0;
6194 var_nonlocal->size = ~0;
6195 var_nonlocal->fullsize = ~0;
6196 var_nonlocal->is_special_var = 1;
6198 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6200 lhs.var = escaped_id;
6203 rhs.var = escaped_id;
6205 process_constraint (new_constraint (lhs, rhs));
6207 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6208 whole variable escapes. */
6210 lhs.var = escaped_id;
6213 rhs.var = escaped_id;
6214 rhs.offset = UNKNOWN_OFFSET;
6215 process_constraint (new_constraint (lhs, rhs));
6217 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6218 everything pointed to by escaped points to what global memory can
6221 lhs.var = escaped_id;
6224 rhs.var = nonlocal_id;
6226 process_constraint (new_constraint (lhs, rhs));
6228 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6229 global memory may point to global memory and escaped memory. */
6231 lhs.var = nonlocal_id;
6233 rhs.type = ADDRESSOF;
6234 rhs.var = nonlocal_id;
6236 process_constraint (new_constraint (lhs, rhs));
6237 rhs.type = ADDRESSOF;
6238 rhs.var = escaped_id;
6240 process_constraint (new_constraint (lhs, rhs));
6242 /* Create the STOREDANYTHING variable, used to represent the set of
6243 variables stored to *ANYTHING. */
6244 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6245 gcc_assert (var_storedanything->id == storedanything_id);
6246 var_storedanything->is_artificial_var = 1;
6247 var_storedanything->offset = 0;
6248 var_storedanything->size = ~0;
6249 var_storedanything->fullsize = ~0;
6250 var_storedanything->is_special_var = 0;
6252 /* Create the INTEGER variable, used to represent that a variable points
6253 to what an INTEGER "points to". */
6254 var_integer = new_var_info (NULL_TREE, "INTEGER");
6255 gcc_assert (var_integer->id == integer_id);
6256 var_integer->is_artificial_var = 1;
6257 var_integer->size = ~0;
6258 var_integer->fullsize = ~0;
6259 var_integer->offset = 0;
6260 var_integer->next = NULL;
6261 var_integer->is_special_var = 1;
6263 /* INTEGER = ANYTHING, because we don't know where a dereference of
6264 a random integer will point to. */
6266 lhs.var = integer_id;
6268 rhs.type = ADDRESSOF;
6269 rhs.var = anything_id;
6271 process_constraint (new_constraint (lhs, rhs));
6274 /* Initialize things necessary to perform PTA */
6277 init_alias_vars (void)
6279 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6281 bitmap_obstack_initialize (&pta_obstack);
6282 bitmap_obstack_initialize (&oldpta_obstack);
6283 bitmap_obstack_initialize (&predbitmap_obstack);
6285 constraint_pool = create_alloc_pool ("Constraint pool",
6286 sizeof (struct constraint), 30);
6287 variable_info_pool = create_alloc_pool ("Variable info pool",
6288 sizeof (struct variable_info), 30);
6289 constraints = VEC_alloc (constraint_t, heap, 8);
6290 varmap = VEC_alloc (varinfo_t, heap, 8);
6291 vi_for_tree = pointer_map_create ();
6292 call_stmt_vars = pointer_map_create ();
6294 memset (&stats, 0, sizeof (stats));
6295 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6296 shared_bitmap_eq, free);
6299 gcc_obstack_init (&fake_var_decl_obstack);
6302 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6303 predecessor edges. */
6306 remove_preds_and_fake_succs (constraint_graph_t graph)
6310 /* Clear the implicit ref and address nodes from the successor
6312 for (i = 0; i < FIRST_REF_NODE; i++)
6314 if (graph->succs[i])
6315 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6316 FIRST_REF_NODE * 2);
6319 /* Free the successor list for the non-ref nodes. */
6320 for (i = FIRST_REF_NODE; i < graph->size; i++)
6322 if (graph->succs[i])
6323 BITMAP_FREE (graph->succs[i]);
6326 /* Now reallocate the size of the successor list as, and blow away
6327 the predecessor bitmaps. */
6328 graph->size = VEC_length (varinfo_t, varmap);
6329 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6331 free (graph->implicit_preds);
6332 graph->implicit_preds = NULL;
6333 free (graph->preds);
6334 graph->preds = NULL;
6335 bitmap_obstack_release (&predbitmap_obstack);
6338 /* Solve the constraint set. */
6341 solve_constraints (void)
6343 struct scc_info *si;
6347 "\nCollapsing static cycles and doing variable "
6350 init_graph (VEC_length (varinfo_t, varmap) * 2);
6353 fprintf (dump_file, "Building predecessor graph\n");
6354 build_pred_graph ();
6357 fprintf (dump_file, "Detecting pointer and location "
6359 si = perform_var_substitution (graph);
6362 fprintf (dump_file, "Rewriting constraints and unifying "
6364 rewrite_constraints (graph, si);
6366 build_succ_graph ();
6367 free_var_substitution_info (si);
6369 if (dump_file && (dump_flags & TDF_GRAPH))
6370 dump_constraint_graph (dump_file);
6372 move_complex_constraints (graph);
6375 fprintf (dump_file, "Uniting pointer but not location equivalent "
6377 unite_pointer_equivalences (graph);
6380 fprintf (dump_file, "Finding indirect cycles\n");
6381 find_indirect_cycles (graph);
6383 /* Implicit nodes and predecessors are no longer necessary at this
6385 remove_preds_and_fake_succs (graph);
6388 fprintf (dump_file, "Solving graph\n");
6390 solve_graph (graph);
6393 dump_sa_points_to_info (dump_file);
6396 /* Create points-to sets for the current function. See the comments
6397 at the start of the file for an algorithmic overview. */
6400 compute_points_to_sets (void)
6406 timevar_push (TV_TREE_PTA);
6410 intra_create_variable_infos ();
6412 /* Now walk all statements and build the constraint set. */
6415 gimple_stmt_iterator gsi;
6417 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6419 gimple phi = gsi_stmt (gsi);
6421 if (is_gimple_reg (gimple_phi_result (phi)))
6422 find_func_aliases (phi);
6425 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6427 gimple stmt = gsi_stmt (gsi);
6429 find_func_aliases (stmt);
6435 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6436 dump_constraints (dump_file, 0);
6439 /* From the constraints compute the points-to sets. */
6440 solve_constraints ();
6442 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6443 find_what_var_points_to (get_varinfo (escaped_id),
6444 &cfun->gimple_df->escaped);
6446 /* Make sure the ESCAPED solution (which is used as placeholder in
6447 other solutions) does not reference itself. This simplifies
6448 points-to solution queries. */
6449 cfun->gimple_df->escaped.escaped = 0;
6451 /* Mark escaped HEAP variables as global. */
6452 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6454 && !vi->is_restrict_var
6455 && !vi->is_global_var)
6456 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6457 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6459 /* Compute the points-to sets for pointer SSA_NAMEs. */
6460 for (i = 0; i < num_ssa_names; ++i)
6462 tree ptr = ssa_name (i);
6464 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6465 find_what_p_points_to (ptr);
6468 /* Compute the call-used/clobbered sets. */
6471 gimple_stmt_iterator gsi;
6473 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6475 gimple stmt = gsi_stmt (gsi);
6476 struct pt_solution *pt;
6477 if (!is_gimple_call (stmt))
6480 pt = gimple_call_use_set (stmt);
6481 if (gimple_call_flags (stmt) & ECF_CONST)
6482 memset (pt, 0, sizeof (struct pt_solution));
6483 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6485 find_what_var_points_to (vi, pt);
6486 /* Escaped (and thus nonlocal) variables are always
6487 implicitly used by calls. */
6488 /* ??? ESCAPED can be empty even though NONLOCAL
6495 /* If there is nothing special about this call then
6496 we have made everything that is used also escape. */
6497 *pt = cfun->gimple_df->escaped;
6501 pt = gimple_call_clobber_set (stmt);
6502 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6503 memset (pt, 0, sizeof (struct pt_solution));
6504 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6506 find_what_var_points_to (vi, pt);
6507 /* Escaped (and thus nonlocal) variables are always
6508 implicitly clobbered by calls. */
6509 /* ??? ESCAPED can be empty even though NONLOCAL
6516 /* If there is nothing special about this call then
6517 we have made everything that is used also escape. */
6518 *pt = cfun->gimple_df->escaped;
6524 timevar_pop (TV_TREE_PTA);
6528 /* Delete created points-to sets. */
6531 delete_points_to_sets (void)
6535 htab_delete (shared_bitmap_table);
6536 if (dump_file && (dump_flags & TDF_STATS))
6537 fprintf (dump_file, "Points to sets created:%d\n",
6538 stats.points_to_sets_created);
6540 pointer_map_destroy (vi_for_tree);
6541 pointer_map_destroy (call_stmt_vars);
6542 bitmap_obstack_release (&pta_obstack);
6543 VEC_free (constraint_t, heap, constraints);
6545 for (i = 0; i < graph->size; i++)
6546 VEC_free (constraint_t, heap, graph->complex[i]);
6547 free (graph->complex);
6550 free (graph->succs);
6552 free (graph->pe_rep);
6553 free (graph->indirect_cycles);
6556 VEC_free (varinfo_t, heap, varmap);
6557 free_alloc_pool (variable_info_pool);
6558 free_alloc_pool (constraint_pool);
6560 obstack_free (&fake_var_decl_obstack, NULL);
6564 /* Compute points-to information for every SSA_NAME pointer in the
6565 current function and compute the transitive closure of escaped
6566 variables to re-initialize the call-clobber states of local variables. */
6569 compute_may_aliases (void)
6571 if (cfun->gimple_df->ipa_pta)
6575 fprintf (dump_file, "\nNot re-computing points-to information "
6576 "because IPA points-to information is available.\n\n");
6578 /* But still dump what we have remaining it. */
6579 dump_alias_info (dump_file);
6581 if (dump_flags & TDF_DETAILS)
6582 dump_referenced_vars (dump_file);
6588 /* For each pointer P_i, determine the sets of variables that P_i may
6589 point-to. Compute the reachability set of escaped and call-used
6591 compute_points_to_sets ();
6593 /* Debugging dumps. */
6596 dump_alias_info (dump_file);
6598 if (dump_flags & TDF_DETAILS)
6599 dump_referenced_vars (dump_file);
6602 /* Deallocate memory used by aliasing data structures and the internal
6603 points-to solution. */
6604 delete_points_to_sets ();
6606 gcc_assert (!need_ssa_update_p (cfun));
6612 gate_tree_pta (void)
6614 return flag_tree_pta;
6617 /* A dummy pass to cause points-to information to be computed via
6618 TODO_rebuild_alias. */
6620 struct gimple_opt_pass pass_build_alias =
6625 gate_tree_pta, /* gate */
6629 0, /* static_pass_number */
6630 TV_NONE, /* tv_id */
6631 PROP_cfg | PROP_ssa, /* properties_required */
6632 0, /* properties_provided */
6633 0, /* properties_destroyed */
6634 0, /* todo_flags_start */
6635 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6639 /* A dummy pass to cause points-to information to be computed via
6640 TODO_rebuild_alias. */
6642 struct gimple_opt_pass pass_build_ealias =
6646 "ealias", /* name */
6647 gate_tree_pta, /* gate */
6651 0, /* static_pass_number */
6652 TV_NONE, /* tv_id */
6653 PROP_cfg | PROP_ssa, /* properties_required */
6654 0, /* properties_provided */
6655 0, /* properties_destroyed */
6656 0, /* todo_flags_start */
6657 TODO_rebuild_alias | TODO_dump_func /* todo_flags_finish */
6662 /* Return true if we should execute IPA PTA. */
6668 /* Don't bother doing anything if the program has errors. */
6672 /* IPA PTA solutions for ESCAPED. */
6673 struct pt_solution ipa_escaped_pt
6674 = { true, false, false, false, false, false, false, NULL };
6676 /* Execute the driver for IPA PTA. */
6678 ipa_pta_execute (void)
6680 struct cgraph_node *node;
6681 struct varpool_node *var;
6688 /* Build the constraints. */
6689 for (node = cgraph_nodes; node; node = node->next)
6691 struct cgraph_node *alias;
6694 /* Nodes without a body are not interesting. Especially do not
6695 visit clones at this point for now - we get duplicate decls
6696 there for inline clones at least. */
6697 if (!gimple_has_body_p (node->decl)
6701 vi = create_function_info_for (node->decl,
6702 alias_get_name (node->decl));
6704 /* Associate the varinfo node with all aliases. */
6705 for (alias = node->same_body; alias; alias = alias->next)
6706 insert_vi_for_tree (alias->decl, vi);
6709 /* Create constraints for global variables and their initializers. */
6710 for (var = varpool_nodes; var; var = var->next)
6712 struct varpool_node *alias;
6715 vi = get_vi_for_tree (var->decl);
6717 /* Associate the varinfo node with all aliases. */
6718 for (alias = var->extra_name; alias; alias = alias->next)
6719 insert_vi_for_tree (alias->decl, vi);
6725 "Generating constraints for global initializers\n\n");
6726 dump_constraints (dump_file, 0);
6727 fprintf (dump_file, "\n");
6729 from = VEC_length (constraint_t, constraints);
6731 for (node = cgraph_nodes; node; node = node->next)
6733 struct function *func;
6737 /* Nodes without a body are not interesting. */
6738 if (!gimple_has_body_p (node->decl)
6745 "Generating constraints for %s", cgraph_node_name (node));
6746 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6747 fprintf (dump_file, " (%s)",
6748 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6749 fprintf (dump_file, "\n");
6752 func = DECL_STRUCT_FUNCTION (node->decl);
6753 old_func_decl = current_function_decl;
6755 current_function_decl = node->decl;
6757 if (node->local.externally_visible)
6759 /* For externally visible functions use local constraints for
6760 their arguments. For local functions we see all callers
6761 and thus do not need initial constraints for parameters. */
6762 intra_create_variable_infos ();
6764 /* We also need to make function return values escape. Nothing
6765 escapes by returning from main though. */
6766 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6769 fi = lookup_vi_for_tree (node->decl);
6770 rvi = first_vi_for_offset (fi, fi_result);
6771 if (rvi && rvi->offset == fi_result)
6773 struct constraint_expr includes;
6774 struct constraint_expr var;
6775 includes.var = escaped_id;
6776 includes.offset = 0;
6777 includes.type = SCALAR;
6781 process_constraint (new_constraint (includes, var));
6786 /* Build constriants for the function body. */
6787 FOR_EACH_BB_FN (bb, func)
6789 gimple_stmt_iterator gsi;
6791 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6794 gimple phi = gsi_stmt (gsi);
6796 if (is_gimple_reg (gimple_phi_result (phi)))
6797 find_func_aliases (phi);
6800 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6802 gimple stmt = gsi_stmt (gsi);
6804 find_func_aliases (stmt);
6805 find_func_clobbers (stmt);
6809 current_function_decl = old_func_decl;
6814 fprintf (dump_file, "\n");
6815 dump_constraints (dump_file, from);
6816 fprintf (dump_file, "\n");
6818 from = VEC_length (constraint_t, constraints);
6821 /* From the constraints compute the points-to sets. */
6822 solve_constraints ();
6824 /* Compute the global points-to sets for ESCAPED.
6825 ??? Note that the computed escape set is not correct
6826 for the whole unit as we fail to consider graph edges to
6827 externally visible functions. */
6828 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6830 /* Make sure the ESCAPED solution (which is used as placeholder in
6831 other solutions) does not reference itself. This simplifies
6832 points-to solution queries. */
6833 ipa_escaped_pt.ipa_escaped = 0;
6835 /* Assign the points-to sets to the SSA names in the unit. */
6836 for (node = cgraph_nodes; node; node = node->next)
6839 struct function *fn;
6843 struct pt_solution uses, clobbers;
6844 struct cgraph_edge *e;
6846 /* Nodes without a body are not interesting. */
6847 if (!gimple_has_body_p (node->decl)
6851 fn = DECL_STRUCT_FUNCTION (node->decl);
6853 /* Compute the points-to sets for pointer SSA_NAMEs. */
6854 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6857 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6858 find_what_p_points_to (ptr);
6861 /* Compute the call-use and call-clobber sets for all direct calls. */
6862 fi = lookup_vi_for_tree (node->decl);
6863 gcc_assert (fi->is_fn_info);
6864 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6866 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6867 for (e = node->callers; e; e = e->next_caller)
6872 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6873 *gimple_call_use_set (e->call_stmt) = uses;
6876 /* Compute the call-use and call-clobber sets for indirect calls
6877 and calls to external functions. */
6878 FOR_EACH_BB_FN (bb, fn)
6880 gimple_stmt_iterator gsi;
6882 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6884 gimple stmt = gsi_stmt (gsi);
6885 struct pt_solution *pt;
6889 if (!is_gimple_call (stmt))
6892 /* Handle direct calls to external functions. */
6893 decl = gimple_call_fndecl (stmt);
6895 && (!(fi = lookup_vi_for_tree (decl))
6896 || !fi->is_fn_info))
6898 pt = gimple_call_use_set (stmt);
6899 if (gimple_call_flags (stmt) & ECF_CONST)
6900 memset (pt, 0, sizeof (struct pt_solution));
6901 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6903 find_what_var_points_to (vi, pt);
6904 /* Escaped (and thus nonlocal) variables are always
6905 implicitly used by calls. */
6906 /* ??? ESCAPED can be empty even though NONLOCAL
6909 pt->ipa_escaped = 1;
6913 /* If there is nothing special about this call then
6914 we have made everything that is used also escape. */
6915 *pt = ipa_escaped_pt;
6919 pt = gimple_call_clobber_set (stmt);
6920 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6921 memset (pt, 0, sizeof (struct pt_solution));
6922 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6924 find_what_var_points_to (vi, pt);
6925 /* Escaped (and thus nonlocal) variables are always
6926 implicitly clobbered by calls. */
6927 /* ??? ESCAPED can be empty even though NONLOCAL
6930 pt->ipa_escaped = 1;
6934 /* If there is nothing special about this call then
6935 we have made everything that is used also escape. */
6936 *pt = ipa_escaped_pt;
6941 /* Handle indirect calls. */
6943 && (fi = get_fi_for_callee (stmt)))
6945 /* We need to accumulate all clobbers/uses of all possible
6947 fi = get_varinfo (find (fi->id));
6948 /* If we cannot constrain the set of functions we'll end up
6949 calling we end up using/clobbering everything. */
6950 if (bitmap_bit_p (fi->solution, anything_id)
6951 || bitmap_bit_p (fi->solution, nonlocal_id)
6952 || bitmap_bit_p (fi->solution, escaped_id))
6954 pt_solution_reset (gimple_call_clobber_set (stmt));
6955 pt_solution_reset (gimple_call_use_set (stmt));
6961 struct pt_solution *uses, *clobbers;
6963 uses = gimple_call_use_set (stmt);
6964 clobbers = gimple_call_clobber_set (stmt);
6965 memset (uses, 0, sizeof (struct pt_solution));
6966 memset (clobbers, 0, sizeof (struct pt_solution));
6967 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
6969 struct pt_solution sol;
6971 vi = get_varinfo (i);
6972 if (!vi->is_fn_info)
6974 /* ??? We could be more precise here? */
6976 uses->ipa_escaped = 1;
6977 clobbers->nonlocal = 1;
6978 clobbers->ipa_escaped = 1;
6982 if (!uses->anything)
6984 find_what_var_points_to
6985 (first_vi_for_offset (vi, fi_uses), &sol);
6986 pt_solution_ior_into (uses, &sol);
6988 if (!clobbers->anything)
6990 find_what_var_points_to
6991 (first_vi_for_offset (vi, fi_clobbers), &sol);
6992 pt_solution_ior_into (clobbers, &sol);
7000 fn->gimple_df->ipa_pta = true;
7003 delete_points_to_sets ();
7010 struct simple_ipa_opt_pass pass_ipa_pta =
7015 gate_ipa_pta, /* gate */
7016 ipa_pta_execute, /* execute */
7019 0, /* static_pass_number */
7020 TV_IPA_PTA, /* tv_id */
7021 0, /* properties_required */
7022 0, /* properties_provided */
7023 0, /* properties_destroyed */
7024 0, /* todo_flags_start */
7025 TODO_update_ssa /* todo_flags_finish */