1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dberlin@dberlin.org>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "basic-block.h"
33 #include "tree-flow.h"
34 #include "tree-inline.h"
35 #include "diagnostic-core.h"
40 #include "tree-pass.h"
42 #include "alloc-pool.h"
43 #include "splay-tree.h"
47 #include "pointer-set.h"
49 /* The idea behind this analyzer is to generate set constraints from the
50 program, then solve the resulting constraints in order to generate the
53 Set constraints are a way of modeling program analysis problems that
54 involve sets. They consist of an inclusion constraint language,
55 describing the variables (each variable is a set) and operations that
56 are involved on the variables, and a set of rules that derive facts
57 from these operations. To solve a system of set constraints, you derive
58 all possible facts under the rules, which gives you the correct sets
61 See "Efficient Field-sensitive pointer analysis for C" by "David
62 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
63 http://citeseer.ist.psu.edu/pearce04efficient.html
65 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
66 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
67 http://citeseer.ist.psu.edu/heintze01ultrafast.html
69 There are three types of real constraint expressions, DEREF,
70 ADDRESSOF, and SCALAR. Each constraint expression consists
71 of a constraint type, a variable, and an offset.
73 SCALAR is a constraint expression type used to represent x, whether
74 it appears on the LHS or the RHS of a statement.
75 DEREF is a constraint expression type used to represent *x, whether
76 it appears on the LHS or the RHS of a statement.
77 ADDRESSOF is a constraint expression used to represent &x, whether
78 it appears on the LHS or the RHS of a statement.
80 Each pointer variable in the program is assigned an integer id, and
81 each field of a structure variable is assigned an integer id as well.
83 Structure variables are linked to their list of fields through a "next
84 field" in each variable that points to the next field in offset
86 Each variable for a structure field has
88 1. "size", that tells the size in bits of that field.
89 2. "fullsize, that tells the size in bits of the entire structure.
90 3. "offset", that tells the offset in bits from the beginning of the
91 structure to this field.
103 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
104 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
105 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
108 In order to solve the system of set constraints, the following is
111 1. Each constraint variable x has a solution set associated with it,
114 2. Constraints are separated into direct, copy, and complex.
115 Direct constraints are ADDRESSOF constraints that require no extra
116 processing, such as P = &Q
117 Copy constraints are those of the form P = Q.
118 Complex constraints are all the constraints involving dereferences
119 and offsets (including offsetted copies).
121 3. All direct constraints of the form P = &Q are processed, such
122 that Q is added to Sol(P)
124 4. All complex constraints for a given constraint variable are stored in a
125 linked list attached to that variable's node.
127 5. A directed graph is built out of the copy constraints. Each
128 constraint variable is a node in the graph, and an edge from
129 Q to P is added for each copy constraint of the form P = Q
131 6. The graph is then walked, and solution sets are
132 propagated along the copy edges, such that an edge from Q to P
133 causes Sol(P) <- Sol(P) union Sol(Q).
135 7. As we visit each node, all complex constraints associated with
136 that node are processed by adding appropriate copy edges to the graph, or the
137 appropriate variables to the solution set.
139 8. The process of walking the graph is iterated until no solution
142 Prior to walking the graph in steps 6 and 7, We perform static
143 cycle elimination on the constraint graph, as well
144 as off-line variable substitution.
146 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
147 on and turned into anything), but isn't. You can just see what offset
148 inside the pointed-to struct it's going to access.
150 TODO: Constant bounded arrays can be handled as if they were structs of the
151 same number of elements.
153 TODO: Modeling heap and incoming pointers becomes much better if we
154 add fields to them as we discover them, which we could do.
156 TODO: We could handle unions, but to be honest, it's probably not
157 worth the pain or slowdown. */
159 /* IPA-PTA optimizations possible.
161 When the indirect function called is ANYTHING we can add disambiguation
162 based on the function signatures (or simply the parameter count which
163 is the varinfo size). We also do not need to consider functions that
164 do not have their address taken.
166 The is_global_var bit which marks escape points is overly conservative
167 in IPA mode. Split it to is_escape_point and is_global_var - only
168 externally visible globals are escape points in IPA mode. This is
169 also needed to fix the pt_solution_includes_global predicate
170 (and thus ptr_deref_may_alias_global_p).
172 The way we introduce DECL_PT_UID to avoid fixing up all points-to
173 sets in the translation unit when we copy a DECL during inlining
174 pessimizes precision. The advantage is that the DECL_PT_UID keeps
175 compile-time and memory usage overhead low - the points-to sets
176 do not grow or get unshared as they would during a fixup phase.
177 An alternative solution is to delay IPA PTA until after all
178 inlining transformations have been applied.
180 The way we propagate clobber/use information isn't optimized.
181 It should use a new complex constraint that properly filters
182 out local variables of the callee (though that would make
183 the sets invalid after inlining). OTOH we might as well
184 admit defeat to WHOPR and simply do all the clobber/use analysis
185 and propagation after PTA finished but before we threw away
186 points-to information for memory variables. WHOPR and PTA
187 do not play along well anyway - the whole constraint solving
188 would need to be done in WPA phase and it will be very interesting
189 to apply the results to local SSA names during LTRANS phase.
191 We probably should compute a per-function unit-ESCAPE solution
192 propagating it simply like the clobber / uses solutions. The
193 solution can go alongside the non-IPA espaced solution and be
194 used to query which vars escape the unit through a function.
196 We never put function decls in points-to sets so we do not
197 keep the set of called functions for indirect calls.
199 And probably more. */
201 static bool use_field_sensitive = true;
202 static int in_ipa_mode = 0;
204 /* Used for predecessor bitmaps. */
205 static bitmap_obstack predbitmap_obstack;
207 /* Used for points-to sets. */
208 static bitmap_obstack pta_obstack;
210 /* Used for oldsolution members of variables. */
211 static bitmap_obstack oldpta_obstack;
213 /* Used for per-solver-iteration bitmaps. */
214 static bitmap_obstack iteration_obstack;
216 static unsigned int create_variable_info_for (tree, const char *);
217 typedef struct constraint_graph *constraint_graph_t;
218 static void unify_nodes (constraint_graph_t, unsigned int, unsigned int, bool);
221 typedef struct constraint *constraint_t;
223 DEF_VEC_P(constraint_t);
224 DEF_VEC_ALLOC_P(constraint_t,heap);
226 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
228 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
230 static struct constraint_stats
232 unsigned int total_vars;
233 unsigned int nonpointer_vars;
234 unsigned int unified_vars_static;
235 unsigned int unified_vars_dynamic;
236 unsigned int iterations;
237 unsigned int num_edges;
238 unsigned int num_implicit_edges;
239 unsigned int points_to_sets_created;
244 /* ID of this variable */
247 /* True if this is a variable created by the constraint analysis, such as
248 heap variables and constraints we had to break up. */
249 unsigned int is_artificial_var : 1;
251 /* True if this is a special variable whose solution set should not be
253 unsigned int is_special_var : 1;
255 /* True for variables whose size is not known or variable. */
256 unsigned int is_unknown_size_var : 1;
258 /* True for (sub-)fields that represent a whole variable. */
259 unsigned int is_full_var : 1;
261 /* True if this is a heap variable. */
262 unsigned int is_heap_var : 1;
264 /* True if this field may contain pointers. */
265 unsigned int may_have_pointers : 1;
267 /* True if this field has only restrict qualified pointers. */
268 unsigned int only_restrict_pointers : 1;
270 /* True if this represents a global variable. */
271 unsigned int is_global_var : 1;
273 /* True if this represents a IPA function info. */
274 unsigned int is_fn_info : 1;
276 /* A link to the variable for the next field in this structure. */
277 struct variable_info *next;
279 /* Offset of this variable, in bits, from the base variable */
280 unsigned HOST_WIDE_INT offset;
282 /* Size of the variable, in bits. */
283 unsigned HOST_WIDE_INT size;
285 /* Full size of the base variable, in bits. */
286 unsigned HOST_WIDE_INT fullsize;
288 /* Name of this variable */
291 /* Tree that this variable is associated with. */
294 /* Points-to set for this variable. */
297 /* Old points-to set for this variable. */
300 typedef struct variable_info *varinfo_t;
302 static varinfo_t first_vi_for_offset (varinfo_t, unsigned HOST_WIDE_INT);
303 static varinfo_t first_or_preceding_vi_for_offset (varinfo_t,
304 unsigned HOST_WIDE_INT);
305 static varinfo_t lookup_vi_for_tree (tree);
307 /* Pool of variable info structures. */
308 static alloc_pool variable_info_pool;
310 DEF_VEC_P(varinfo_t);
312 DEF_VEC_ALLOC_P(varinfo_t, heap);
314 /* Table of variable info structures for constraint variables.
315 Indexed directly by variable info id. */
316 static VEC(varinfo_t,heap) *varmap;
318 /* Return the varmap element N */
320 static inline varinfo_t
321 get_varinfo (unsigned int n)
323 return VEC_index (varinfo_t, varmap, n);
326 /* Static IDs for the special variables. */
327 enum { nothing_id = 0, anything_id = 1, readonly_id = 2,
328 escaped_id = 3, nonlocal_id = 4,
329 storedanything_id = 5, integer_id = 6 };
331 /* Return a new variable info structure consisting for a variable
332 named NAME, and using constraint graph node NODE. Append it
333 to the vector of variable info structures. */
336 new_var_info (tree t, const char *name)
338 unsigned index = VEC_length (varinfo_t, varmap);
339 varinfo_t ret = (varinfo_t) pool_alloc (variable_info_pool);
344 /* Vars without decl are artificial and do not have sub-variables. */
345 ret->is_artificial_var = (t == NULL_TREE);
346 ret->is_special_var = false;
347 ret->is_unknown_size_var = false;
348 ret->is_full_var = (t == NULL_TREE);
349 ret->is_heap_var = false;
350 ret->may_have_pointers = true;
351 ret->only_restrict_pointers = false;
352 ret->is_global_var = (t == NULL_TREE);
353 ret->is_fn_info = false;
355 ret->is_global_var = (is_global_var (t)
356 /* We have to treat even local register variables
358 || (TREE_CODE (t) == VAR_DECL
359 && DECL_HARD_REGISTER (t)));
360 ret->solution = BITMAP_ALLOC (&pta_obstack);
361 ret->oldsolution = NULL;
366 VEC_safe_push (varinfo_t, heap, varmap, ret);
372 /* A map mapping call statements to per-stmt variables for uses
373 and clobbers specific to the call. */
374 struct pointer_map_t *call_stmt_vars;
376 /* Lookup or create the variable for the call statement CALL. */
379 get_call_vi (gimple call)
384 slot_p = pointer_map_insert (call_stmt_vars, call);
386 return (varinfo_t) *slot_p;
388 vi = new_var_info (NULL_TREE, "CALLUSED");
392 vi->is_full_var = true;
394 vi->next = vi2 = new_var_info (NULL_TREE, "CALLCLOBBERED");
398 vi2->is_full_var = true;
400 *slot_p = (void *) vi;
404 /* Lookup the variable for the call statement CALL representing
405 the uses. Returns NULL if there is nothing special about this call. */
408 lookup_call_use_vi (gimple call)
412 slot_p = pointer_map_contains (call_stmt_vars, call);
414 return (varinfo_t) *slot_p;
419 /* Lookup the variable for the call statement CALL representing
420 the clobbers. Returns NULL if there is nothing special about this call. */
423 lookup_call_clobber_vi (gimple call)
425 varinfo_t uses = lookup_call_use_vi (call);
432 /* Lookup or create the variable for the call statement CALL representing
436 get_call_use_vi (gimple call)
438 return get_call_vi (call);
441 /* Lookup or create the variable for the call statement CALL representing
444 static varinfo_t ATTRIBUTE_UNUSED
445 get_call_clobber_vi (gimple call)
447 return get_call_vi (call)->next;
451 typedef enum {SCALAR, DEREF, ADDRESSOF} constraint_expr_type;
453 /* An expression that appears in a constraint. */
455 struct constraint_expr
457 /* Constraint type. */
458 constraint_expr_type type;
460 /* Variable we are referring to in the constraint. */
463 /* Offset, in bits, of this constraint from the beginning of
464 variables it ends up referring to.
466 IOW, in a deref constraint, we would deref, get the result set,
467 then add OFFSET to each member. */
468 HOST_WIDE_INT offset;
471 /* Use 0x8000... as special unknown offset. */
472 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
474 typedef struct constraint_expr ce_s;
476 DEF_VEC_ALLOC_O(ce_s, heap);
477 static void get_constraint_for_1 (tree, VEC(ce_s, heap) **, bool, bool);
478 static void get_constraint_for (tree, VEC(ce_s, heap) **);
479 static void get_constraint_for_rhs (tree, VEC(ce_s, heap) **);
480 static void do_deref (VEC (ce_s, heap) **);
482 /* Our set constraints are made up of two constraint expressions, one
485 As described in the introduction, our set constraints each represent an
486 operation between set valued variables.
490 struct constraint_expr lhs;
491 struct constraint_expr rhs;
494 /* List of constraints that we use to build the constraint graph from. */
496 static VEC(constraint_t,heap) *constraints;
497 static alloc_pool constraint_pool;
499 /* The constraint graph is represented as an array of bitmaps
500 containing successor nodes. */
502 struct constraint_graph
504 /* Size of this graph, which may be different than the number of
505 nodes in the variable map. */
508 /* Explicit successors of each node. */
511 /* Implicit predecessors of each node (Used for variable
513 bitmap *implicit_preds;
515 /* Explicit predecessors of each node (Used for variable substitution). */
518 /* Indirect cycle representatives, or -1 if the node has no indirect
520 int *indirect_cycles;
522 /* Representative node for a node. rep[a] == a unless the node has
526 /* Equivalence class representative for a label. This is used for
527 variable substitution. */
530 /* Pointer equivalence label for a node. All nodes with the same
531 pointer equivalence label can be unified together at some point
532 (either during constraint optimization or after the constraint
536 /* Pointer equivalence representative for a label. This is used to
537 handle nodes that are pointer equivalent but not location
538 equivalent. We can unite these once the addressof constraints
539 are transformed into initial points-to sets. */
542 /* Pointer equivalence label for each node, used during variable
544 unsigned int *pointer_label;
546 /* Location equivalence label for each node, used during location
547 equivalence finding. */
548 unsigned int *loc_label;
550 /* Pointed-by set for each node, used during location equivalence
551 finding. This is pointed-by rather than pointed-to, because it
552 is constructed using the predecessor graph. */
555 /* Points to sets for pointer equivalence. This is *not* the actual
556 points-to sets for nodes. */
559 /* Bitmap of nodes where the bit is set if the node is a direct
560 node. Used for variable substitution. */
561 sbitmap direct_nodes;
563 /* Bitmap of nodes where the bit is set if the node is address
564 taken. Used for variable substitution. */
565 bitmap address_taken;
567 /* Vector of complex constraints for each graph node. Complex
568 constraints are those involving dereferences or offsets that are
570 VEC(constraint_t,heap) **complex;
573 static constraint_graph_t graph;
575 /* During variable substitution and the offline version of indirect
576 cycle finding, we create nodes to represent dereferences and
577 address taken constraints. These represent where these start and
579 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
580 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
582 /* Return the representative node for NODE, if NODE has been unioned
584 This function performs path compression along the way to finding
585 the representative. */
588 find (unsigned int node)
590 gcc_assert (node < graph->size);
591 if (graph->rep[node] != node)
592 return graph->rep[node] = find (graph->rep[node]);
596 /* Union the TO and FROM nodes to the TO nodes.
597 Note that at some point in the future, we may want to do
598 union-by-rank, in which case we are going to have to return the
599 node we unified to. */
602 unite (unsigned int to, unsigned int from)
604 gcc_assert (to < graph->size && from < graph->size);
605 if (to != from && graph->rep[from] != to)
607 graph->rep[from] = to;
613 /* Create a new constraint consisting of LHS and RHS expressions. */
616 new_constraint (const struct constraint_expr lhs,
617 const struct constraint_expr rhs)
619 constraint_t ret = (constraint_t) pool_alloc (constraint_pool);
625 /* Print out constraint C to FILE. */
628 dump_constraint (FILE *file, constraint_t c)
630 if (c->lhs.type == ADDRESSOF)
632 else if (c->lhs.type == DEREF)
634 fprintf (file, "%s", get_varinfo (c->lhs.var)->name);
635 if (c->lhs.offset == UNKNOWN_OFFSET)
636 fprintf (file, " + UNKNOWN");
637 else if (c->lhs.offset != 0)
638 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->lhs.offset);
639 fprintf (file, " = ");
640 if (c->rhs.type == ADDRESSOF)
642 else if (c->rhs.type == DEREF)
644 fprintf (file, "%s", get_varinfo (c->rhs.var)->name);
645 if (c->rhs.offset == UNKNOWN_OFFSET)
646 fprintf (file, " + UNKNOWN");
647 else if (c->rhs.offset != 0)
648 fprintf (file, " + " HOST_WIDE_INT_PRINT_DEC, c->rhs.offset);
652 void debug_constraint (constraint_t);
653 void debug_constraints (void);
654 void debug_constraint_graph (void);
655 void debug_solution_for_var (unsigned int);
656 void debug_sa_points_to_info (void);
658 /* Print out constraint C to stderr. */
661 debug_constraint (constraint_t c)
663 dump_constraint (stderr, c);
664 fprintf (stderr, "\n");
667 /* Print out all constraints to FILE */
670 dump_constraints (FILE *file, int from)
674 for (i = from; VEC_iterate (constraint_t, constraints, i, c); i++)
677 dump_constraint (file, c);
678 fprintf (file, "\n");
682 /* Print out all constraints to stderr. */
685 debug_constraints (void)
687 dump_constraints (stderr, 0);
690 /* Print the constraint graph in dot format. */
693 dump_constraint_graph (FILE *file)
697 /* Only print the graph if it has already been initialized: */
701 /* Prints the header of the dot file: */
702 fprintf (file, "strict digraph {\n");
703 fprintf (file, " node [\n shape = box\n ]\n");
704 fprintf (file, " edge [\n fontsize = \"12\"\n ]\n");
705 fprintf (file, "\n // List of nodes and complex constraints in "
706 "the constraint graph:\n");
708 /* The next lines print the nodes in the graph together with the
709 complex constraints attached to them. */
710 for (i = 0; i < graph->size; i++)
714 if (i < FIRST_REF_NODE)
715 fprintf (file, "\"%s\"", get_varinfo (i)->name);
717 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
718 if (graph->complex[i])
722 fprintf (file, " [label=\"\\N\\n");
723 for (j = 0; VEC_iterate (constraint_t, graph->complex[i], j, c); ++j)
725 dump_constraint (file, c);
726 fprintf (file, "\\l");
728 fprintf (file, "\"]");
730 fprintf (file, ";\n");
733 /* Go over the edges. */
734 fprintf (file, "\n // Edges in the constraint graph:\n");
735 for (i = 0; i < graph->size; i++)
741 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i], 0, j, bi)
743 unsigned to = find (j);
746 if (i < FIRST_REF_NODE)
747 fprintf (file, "\"%s\"", get_varinfo (i)->name);
749 fprintf (file, "\"*%s\"", get_varinfo (i - FIRST_REF_NODE)->name);
750 fprintf (file, " -> ");
751 if (to < FIRST_REF_NODE)
752 fprintf (file, "\"%s\"", get_varinfo (to)->name);
754 fprintf (file, "\"*%s\"", get_varinfo (to - FIRST_REF_NODE)->name);
755 fprintf (file, ";\n");
759 /* Prints the tail of the dot file. */
760 fprintf (file, "}\n");
763 /* Print out the constraint graph to stderr. */
766 debug_constraint_graph (void)
768 dump_constraint_graph (stderr);
773 The solver is a simple worklist solver, that works on the following
776 sbitmap changed_nodes = all zeroes;
778 For each node that is not already collapsed:
780 set bit in changed nodes
782 while (changed_count > 0)
784 compute topological ordering for constraint graph
786 find and collapse cycles in the constraint graph (updating
787 changed if necessary)
789 for each node (n) in the graph in topological order:
792 Process each complex constraint associated with the node,
793 updating changed if necessary.
795 For each outgoing edge from n, propagate the solution from n to
796 the destination of the edge, updating changed as necessary.
800 /* Return true if two constraint expressions A and B are equal. */
803 constraint_expr_equal (struct constraint_expr a, struct constraint_expr b)
805 return a.type == b.type && a.var == b.var && a.offset == b.offset;
808 /* Return true if constraint expression A is less than constraint expression
809 B. This is just arbitrary, but consistent, in order to give them an
813 constraint_expr_less (struct constraint_expr a, struct constraint_expr b)
815 if (a.type == b.type)
818 return a.offset < b.offset;
820 return a.var < b.var;
823 return a.type < b.type;
826 /* Return true if constraint A is less than constraint B. This is just
827 arbitrary, but consistent, in order to give them an ordering. */
830 constraint_less (const constraint_t a, const constraint_t b)
832 if (constraint_expr_less (a->lhs, b->lhs))
834 else if (constraint_expr_less (b->lhs, a->lhs))
837 return constraint_expr_less (a->rhs, b->rhs);
840 /* Return true if two constraints A and B are equal. */
843 constraint_equal (struct constraint a, struct constraint b)
845 return constraint_expr_equal (a.lhs, b.lhs)
846 && constraint_expr_equal (a.rhs, b.rhs);
850 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
853 constraint_vec_find (VEC(constraint_t,heap) *vec,
854 struct constraint lookfor)
862 place = VEC_lower_bound (constraint_t, vec, &lookfor, constraint_less);
863 if (place >= VEC_length (constraint_t, vec))
865 found = VEC_index (constraint_t, vec, place);
866 if (!constraint_equal (*found, lookfor))
871 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
874 constraint_set_union (VEC(constraint_t,heap) **to,
875 VEC(constraint_t,heap) **from)
880 FOR_EACH_VEC_ELT (constraint_t, *from, i, c)
882 if (constraint_vec_find (*to, *c) == NULL)
884 unsigned int place = VEC_lower_bound (constraint_t, *to, c,
886 VEC_safe_insert (constraint_t, heap, *to, place, c);
891 /* Expands the solution in SET to all sub-fields of variables included.
892 Union the expanded result into RESULT. */
895 solution_set_expand (bitmap result, bitmap set)
901 /* In a first pass record all variables we need to add all
902 sub-fields off. This avoids quadratic behavior. */
903 EXECUTE_IF_SET_IN_BITMAP (set, 0, j, bi)
905 varinfo_t v = get_varinfo (j);
906 if (v->is_artificial_var
909 v = lookup_vi_for_tree (v->decl);
911 vars = BITMAP_ALLOC (NULL);
912 bitmap_set_bit (vars, v->id);
915 /* In the second pass now do the addition to the solution and
916 to speed up solving add it to the delta as well. */
919 EXECUTE_IF_SET_IN_BITMAP (vars, 0, j, bi)
921 varinfo_t v = get_varinfo (j);
922 for (; v != NULL; v = v->next)
923 bitmap_set_bit (result, v->id);
929 /* Take a solution set SET, add OFFSET to each member of the set, and
930 overwrite SET with the result when done. */
933 solution_set_add (bitmap set, HOST_WIDE_INT offset)
935 bitmap result = BITMAP_ALLOC (&iteration_obstack);
939 /* If the offset is unknown we have to expand the solution to
941 if (offset == UNKNOWN_OFFSET)
943 solution_set_expand (set, set);
947 EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
949 varinfo_t vi = get_varinfo (i);
951 /* If this is a variable with just one field just set its bit
953 if (vi->is_artificial_var
954 || vi->is_unknown_size_var
956 bitmap_set_bit (result, i);
959 unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
961 /* If the offset makes the pointer point to before the
962 variable use offset zero for the field lookup. */
964 && fieldoffset > vi->offset)
968 vi = first_or_preceding_vi_for_offset (vi, fieldoffset);
970 bitmap_set_bit (result, vi->id);
971 /* If the result is not exactly at fieldoffset include the next
972 field as well. See get_constraint_for_ptr_offset for more
974 if (vi->offset != fieldoffset
976 bitmap_set_bit (result, vi->next->id);
980 bitmap_copy (set, result);
981 BITMAP_FREE (result);
984 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
988 set_union_with_increment (bitmap to, bitmap from, HOST_WIDE_INT inc)
991 return bitmap_ior_into (to, from);
997 tmp = BITMAP_ALLOC (&iteration_obstack);
998 bitmap_copy (tmp, from);
999 solution_set_add (tmp, inc);
1000 res = bitmap_ior_into (to, tmp);
1006 /* Insert constraint C into the list of complex constraints for graph
1010 insert_into_complex (constraint_graph_t graph,
1011 unsigned int var, constraint_t c)
1013 VEC (constraint_t, heap) *complex = graph->complex[var];
1014 unsigned int place = VEC_lower_bound (constraint_t, complex, c,
1017 /* Only insert constraints that do not already exist. */
1018 if (place >= VEC_length (constraint_t, complex)
1019 || !constraint_equal (*c, *VEC_index (constraint_t, complex, place)))
1020 VEC_safe_insert (constraint_t, heap, graph->complex[var], place, c);
1024 /* Condense two variable nodes into a single variable node, by moving
1025 all associated info from SRC to TO. */
1028 merge_node_constraints (constraint_graph_t graph, unsigned int to,
1034 gcc_assert (find (from) == to);
1036 /* Move all complex constraints from src node into to node */
1037 FOR_EACH_VEC_ELT (constraint_t, graph->complex[from], i, c)
1039 /* In complex constraints for node src, we may have either
1040 a = *src, and *src = a, or an offseted constraint which are
1041 always added to the rhs node's constraints. */
1043 if (c->rhs.type == DEREF)
1045 else if (c->lhs.type == DEREF)
1050 constraint_set_union (&graph->complex[to], &graph->complex[from]);
1051 VEC_free (constraint_t, heap, graph->complex[from]);
1052 graph->complex[from] = NULL;
1056 /* Remove edges involving NODE from GRAPH. */
1059 clear_edges_for_node (constraint_graph_t graph, unsigned int node)
1061 if (graph->succs[node])
1062 BITMAP_FREE (graph->succs[node]);
1065 /* Merge GRAPH nodes FROM and TO into node TO. */
1068 merge_graph_nodes (constraint_graph_t graph, unsigned int to,
1071 if (graph->indirect_cycles[from] != -1)
1073 /* If we have indirect cycles with the from node, and we have
1074 none on the to node, the to node has indirect cycles from the
1075 from node now that they are unified.
1076 If indirect cycles exist on both, unify the nodes that they
1077 are in a cycle with, since we know they are in a cycle with
1079 if (graph->indirect_cycles[to] == -1)
1080 graph->indirect_cycles[to] = graph->indirect_cycles[from];
1083 /* Merge all the successor edges. */
1084 if (graph->succs[from])
1086 if (!graph->succs[to])
1087 graph->succs[to] = BITMAP_ALLOC (&pta_obstack);
1088 bitmap_ior_into (graph->succs[to],
1089 graph->succs[from]);
1092 clear_edges_for_node (graph, from);
1096 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1097 it doesn't exist in the graph already. */
1100 add_implicit_graph_edge (constraint_graph_t graph, unsigned int to,
1106 if (!graph->implicit_preds[to])
1107 graph->implicit_preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1109 if (bitmap_set_bit (graph->implicit_preds[to], from))
1110 stats.num_implicit_edges++;
1113 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1114 it doesn't exist in the graph already.
1115 Return false if the edge already existed, true otherwise. */
1118 add_pred_graph_edge (constraint_graph_t graph, unsigned int to,
1121 if (!graph->preds[to])
1122 graph->preds[to] = BITMAP_ALLOC (&predbitmap_obstack);
1123 bitmap_set_bit (graph->preds[to], from);
1126 /* Add a graph edge to GRAPH, going from FROM to TO if
1127 it doesn't exist in the graph already.
1128 Return false if the edge already existed, true otherwise. */
1131 add_graph_edge (constraint_graph_t graph, unsigned int to,
1142 if (!graph->succs[from])
1143 graph->succs[from] = BITMAP_ALLOC (&pta_obstack);
1144 if (bitmap_set_bit (graph->succs[from], to))
1147 if (to < FIRST_REF_NODE && from < FIRST_REF_NODE)
1155 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1158 valid_graph_edge (constraint_graph_t graph, unsigned int src,
1161 return (graph->succs[dest]
1162 && bitmap_bit_p (graph->succs[dest], src));
1165 /* Initialize the constraint graph structure to contain SIZE nodes. */
1168 init_graph (unsigned int size)
1172 graph = XCNEW (struct constraint_graph);
1174 graph->succs = XCNEWVEC (bitmap, graph->size);
1175 graph->indirect_cycles = XNEWVEC (int, graph->size);
1176 graph->rep = XNEWVEC (unsigned int, graph->size);
1177 graph->complex = XCNEWVEC (VEC(constraint_t, heap) *, size);
1178 graph->pe = XCNEWVEC (unsigned int, graph->size);
1179 graph->pe_rep = XNEWVEC (int, graph->size);
1181 for (j = 0; j < graph->size; j++)
1184 graph->pe_rep[j] = -1;
1185 graph->indirect_cycles[j] = -1;
1189 /* Build the constraint graph, adding only predecessor edges right now. */
1192 build_pred_graph (void)
1198 graph->implicit_preds = XCNEWVEC (bitmap, graph->size);
1199 graph->preds = XCNEWVEC (bitmap, graph->size);
1200 graph->pointer_label = XCNEWVEC (unsigned int, graph->size);
1201 graph->loc_label = XCNEWVEC (unsigned int, graph->size);
1202 graph->pointed_by = XCNEWVEC (bitmap, graph->size);
1203 graph->points_to = XCNEWVEC (bitmap, graph->size);
1204 graph->eq_rep = XNEWVEC (int, graph->size);
1205 graph->direct_nodes = sbitmap_alloc (graph->size);
1206 graph->address_taken = BITMAP_ALLOC (&predbitmap_obstack);
1207 sbitmap_zero (graph->direct_nodes);
1209 for (j = 0; j < FIRST_REF_NODE; j++)
1211 if (!get_varinfo (j)->is_special_var)
1212 SET_BIT (graph->direct_nodes, j);
1215 for (j = 0; j < graph->size; j++)
1216 graph->eq_rep[j] = -1;
1218 for (j = 0; j < VEC_length (varinfo_t, varmap); j++)
1219 graph->indirect_cycles[j] = -1;
1221 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1223 struct constraint_expr lhs = c->lhs;
1224 struct constraint_expr rhs = c->rhs;
1225 unsigned int lhsvar = lhs.var;
1226 unsigned int rhsvar = rhs.var;
1228 if (lhs.type == DEREF)
1231 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1232 add_pred_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1234 else if (rhs.type == DEREF)
1237 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1238 add_pred_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1240 RESET_BIT (graph->direct_nodes, lhsvar);
1242 else if (rhs.type == ADDRESSOF)
1247 if (graph->points_to[lhsvar] == NULL)
1248 graph->points_to[lhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1249 bitmap_set_bit (graph->points_to[lhsvar], rhsvar);
1251 if (graph->pointed_by[rhsvar] == NULL)
1252 graph->pointed_by[rhsvar] = BITMAP_ALLOC (&predbitmap_obstack);
1253 bitmap_set_bit (graph->pointed_by[rhsvar], lhsvar);
1255 /* Implicitly, *x = y */
1256 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1258 /* All related variables are no longer direct nodes. */
1259 RESET_BIT (graph->direct_nodes, rhsvar);
1260 v = get_varinfo (rhsvar);
1261 if (!v->is_full_var)
1263 v = lookup_vi_for_tree (v->decl);
1266 RESET_BIT (graph->direct_nodes, v->id);
1271 bitmap_set_bit (graph->address_taken, rhsvar);
1273 else if (lhsvar > anything_id
1274 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1277 add_pred_graph_edge (graph, lhsvar, rhsvar);
1278 /* Implicitly, *x = *y */
1279 add_implicit_graph_edge (graph, FIRST_REF_NODE + lhsvar,
1280 FIRST_REF_NODE + rhsvar);
1282 else if (lhs.offset != 0 || rhs.offset != 0)
1284 if (rhs.offset != 0)
1285 RESET_BIT (graph->direct_nodes, lhs.var);
1286 else if (lhs.offset != 0)
1287 RESET_BIT (graph->direct_nodes, rhs.var);
1292 /* Build the constraint graph, adding successor edges. */
1295 build_succ_graph (void)
1300 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
1302 struct constraint_expr lhs;
1303 struct constraint_expr rhs;
1304 unsigned int lhsvar;
1305 unsigned int rhsvar;
1312 lhsvar = find (lhs.var);
1313 rhsvar = find (rhs.var);
1315 if (lhs.type == DEREF)
1317 if (rhs.offset == 0 && lhs.offset == 0 && rhs.type == SCALAR)
1318 add_graph_edge (graph, FIRST_REF_NODE + lhsvar, rhsvar);
1320 else if (rhs.type == DEREF)
1322 if (rhs.offset == 0 && lhs.offset == 0 && lhs.type == SCALAR)
1323 add_graph_edge (graph, lhsvar, FIRST_REF_NODE + rhsvar);
1325 else if (rhs.type == ADDRESSOF)
1328 gcc_assert (find (rhs.var) == rhs.var);
1329 bitmap_set_bit (get_varinfo (lhsvar)->solution, rhsvar);
1331 else if (lhsvar > anything_id
1332 && lhsvar != rhsvar && lhs.offset == 0 && rhs.offset == 0)
1334 add_graph_edge (graph, lhsvar, rhsvar);
1338 /* Add edges from STOREDANYTHING to all non-direct nodes that can
1339 receive pointers. */
1340 t = find (storedanything_id);
1341 for (i = integer_id + 1; i < FIRST_REF_NODE; ++i)
1343 if (!TEST_BIT (graph->direct_nodes, i)
1344 && get_varinfo (i)->may_have_pointers)
1345 add_graph_edge (graph, find (i), t);
1348 /* Everything stored to ANYTHING also potentially escapes. */
1349 add_graph_edge (graph, find (escaped_id), t);
1353 /* Changed variables on the last iteration. */
1354 static bitmap changed;
1356 /* Strongly Connected Component visitation info. */
1363 unsigned int *node_mapping;
1365 VEC(unsigned,heap) *scc_stack;
1369 /* Recursive routine to find strongly connected components in GRAPH.
1370 SI is the SCC info to store the information in, and N is the id of current
1371 graph node we are processing.
1373 This is Tarjan's strongly connected component finding algorithm, as
1374 modified by Nuutila to keep only non-root nodes on the stack.
1375 The algorithm can be found in "On finding the strongly connected
1376 connected components in a directed graph" by Esko Nuutila and Eljas
1377 Soisalon-Soininen, in Information Processing Letters volume 49,
1378 number 1, pages 9-14. */
1381 scc_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
1385 unsigned int my_dfs;
1387 SET_BIT (si->visited, n);
1388 si->dfs[n] = si->current_index ++;
1389 my_dfs = si->dfs[n];
1391 /* Visit all the successors. */
1392 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[n], 0, i, bi)
1396 if (i > LAST_REF_NODE)
1400 if (TEST_BIT (si->deleted, w))
1403 if (!TEST_BIT (si->visited, w))
1404 scc_visit (graph, si, w);
1406 unsigned int t = find (w);
1407 unsigned int nnode = find (n);
1408 gcc_assert (nnode == n);
1410 if (si->dfs[t] < si->dfs[nnode])
1411 si->dfs[n] = si->dfs[t];
1415 /* See if any components have been identified. */
1416 if (si->dfs[n] == my_dfs)
1418 if (VEC_length (unsigned, si->scc_stack) > 0
1419 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1421 bitmap scc = BITMAP_ALLOC (NULL);
1422 unsigned int lowest_node;
1425 bitmap_set_bit (scc, n);
1427 while (VEC_length (unsigned, si->scc_stack) != 0
1428 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
1430 unsigned int w = VEC_pop (unsigned, si->scc_stack);
1432 bitmap_set_bit (scc, w);
1435 lowest_node = bitmap_first_set_bit (scc);
1436 gcc_assert (lowest_node < FIRST_REF_NODE);
1438 /* Collapse the SCC nodes into a single node, and mark the
1440 EXECUTE_IF_SET_IN_BITMAP (scc, 0, i, bi)
1442 if (i < FIRST_REF_NODE)
1444 if (unite (lowest_node, i))
1445 unify_nodes (graph, lowest_node, i, false);
1449 unite (lowest_node, i);
1450 graph->indirect_cycles[i - FIRST_REF_NODE] = lowest_node;
1454 SET_BIT (si->deleted, n);
1457 VEC_safe_push (unsigned, heap, si->scc_stack, n);
1460 /* Unify node FROM into node TO, updating the changed count if
1461 necessary when UPDATE_CHANGED is true. */
1464 unify_nodes (constraint_graph_t graph, unsigned int to, unsigned int from,
1465 bool update_changed)
1468 gcc_assert (to != from && find (to) == to);
1469 if (dump_file && (dump_flags & TDF_DETAILS))
1470 fprintf (dump_file, "Unifying %s to %s\n",
1471 get_varinfo (from)->name,
1472 get_varinfo (to)->name);
1475 stats.unified_vars_dynamic++;
1477 stats.unified_vars_static++;
1479 merge_graph_nodes (graph, to, from);
1480 merge_node_constraints (graph, to, from);
1482 /* Mark TO as changed if FROM was changed. If TO was already marked
1483 as changed, decrease the changed count. */
1486 && bitmap_bit_p (changed, from))
1488 bitmap_clear_bit (changed, from);
1489 bitmap_set_bit (changed, to);
1491 if (get_varinfo (from)->solution)
1493 /* If the solution changes because of the merging, we need to mark
1494 the variable as changed. */
1495 if (bitmap_ior_into (get_varinfo (to)->solution,
1496 get_varinfo (from)->solution))
1499 bitmap_set_bit (changed, to);
1502 BITMAP_FREE (get_varinfo (from)->solution);
1503 if (get_varinfo (from)->oldsolution)
1504 BITMAP_FREE (get_varinfo (from)->oldsolution);
1506 if (stats.iterations > 0
1507 && get_varinfo (to)->oldsolution)
1508 BITMAP_FREE (get_varinfo (to)->oldsolution);
1510 if (valid_graph_edge (graph, to, to))
1512 if (graph->succs[to])
1513 bitmap_clear_bit (graph->succs[to], to);
1517 /* Information needed to compute the topological ordering of a graph. */
1521 /* sbitmap of visited nodes. */
1523 /* Array that stores the topological order of the graph, *in
1525 VEC(unsigned,heap) *topo_order;
1529 /* Initialize and return a topological info structure. */
1531 static struct topo_info *
1532 init_topo_info (void)
1534 size_t size = graph->size;
1535 struct topo_info *ti = XNEW (struct topo_info);
1536 ti->visited = sbitmap_alloc (size);
1537 sbitmap_zero (ti->visited);
1538 ti->topo_order = VEC_alloc (unsigned, heap, 1);
1543 /* Free the topological sort info pointed to by TI. */
1546 free_topo_info (struct topo_info *ti)
1548 sbitmap_free (ti->visited);
1549 VEC_free (unsigned, heap, ti->topo_order);
1553 /* Visit the graph in topological order, and store the order in the
1554 topo_info structure. */
1557 topo_visit (constraint_graph_t graph, struct topo_info *ti,
1563 SET_BIT (ti->visited, n);
1565 if (graph->succs[n])
1566 EXECUTE_IF_SET_IN_BITMAP (graph->succs[n], 0, j, bi)
1568 if (!TEST_BIT (ti->visited, j))
1569 topo_visit (graph, ti, j);
1572 VEC_safe_push (unsigned, heap, ti->topo_order, n);
1575 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1576 starting solution for y. */
1579 do_sd_constraint (constraint_graph_t graph, constraint_t c,
1582 unsigned int lhs = c->lhs.var;
1584 bitmap sol = get_varinfo (lhs)->solution;
1587 HOST_WIDE_INT roffset = c->rhs.offset;
1589 /* Our IL does not allow this. */
1590 gcc_assert (c->lhs.offset == 0);
1592 /* If the solution of Y contains anything it is good enough to transfer
1594 if (bitmap_bit_p (delta, anything_id))
1596 flag |= bitmap_set_bit (sol, anything_id);
1600 /* If we do not know at with offset the rhs is dereferenced compute
1601 the reachability set of DELTA, conservatively assuming it is
1602 dereferenced at all valid offsets. */
1603 if (roffset == UNKNOWN_OFFSET)
1605 solution_set_expand (delta, delta);
1606 /* No further offset processing is necessary. */
1610 /* For each variable j in delta (Sol(y)), add
1611 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1612 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1614 varinfo_t v = get_varinfo (j);
1615 HOST_WIDE_INT fieldoffset = v->offset + roffset;
1619 fieldoffset = v->offset;
1620 else if (roffset != 0)
1621 v = first_vi_for_offset (v, fieldoffset);
1622 /* If the access is outside of the variable we can ignore it. */
1630 /* Adding edges from the special vars is pointless.
1631 They don't have sets that can change. */
1632 if (get_varinfo (t)->is_special_var)
1633 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1634 /* Merging the solution from ESCAPED needlessly increases
1635 the set. Use ESCAPED as representative instead. */
1636 else if (v->id == escaped_id)
1637 flag |= bitmap_set_bit (sol, escaped_id);
1638 else if (v->may_have_pointers
1639 && add_graph_edge (graph, lhs, t))
1640 flag |= bitmap_ior_into (sol, get_varinfo (t)->solution);
1642 /* If the variable is not exactly at the requested offset
1643 we have to include the next one. */
1644 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1649 fieldoffset = v->offset;
1655 /* If the LHS solution changed, mark the var as changed. */
1658 get_varinfo (lhs)->solution = sol;
1659 bitmap_set_bit (changed, lhs);
1663 /* Process a constraint C that represents *(x + off) = y using DELTA
1664 as the starting solution for x. */
1667 do_ds_constraint (constraint_t c, bitmap delta)
1669 unsigned int rhs = c->rhs.var;
1670 bitmap sol = get_varinfo (rhs)->solution;
1673 HOST_WIDE_INT loff = c->lhs.offset;
1674 bool escaped_p = false;
1676 /* Our IL does not allow this. */
1677 gcc_assert (c->rhs.offset == 0);
1679 /* If the solution of y contains ANYTHING simply use the ANYTHING
1680 solution. This avoids needlessly increasing the points-to sets. */
1681 if (bitmap_bit_p (sol, anything_id))
1682 sol = get_varinfo (find (anything_id))->solution;
1684 /* If the solution for x contains ANYTHING we have to merge the
1685 solution of y into all pointer variables which we do via
1687 if (bitmap_bit_p (delta, anything_id))
1689 unsigned t = find (storedanything_id);
1690 if (add_graph_edge (graph, t, rhs))
1692 if (bitmap_ior_into (get_varinfo (t)->solution, sol))
1693 bitmap_set_bit (changed, t);
1698 /* If we do not know at with offset the rhs is dereferenced compute
1699 the reachability set of DELTA, conservatively assuming it is
1700 dereferenced at all valid offsets. */
1701 if (loff == UNKNOWN_OFFSET)
1703 solution_set_expand (delta, delta);
1707 /* For each member j of delta (Sol(x)), add an edge from y to j and
1708 union Sol(y) into Sol(j) */
1709 EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
1711 varinfo_t v = get_varinfo (j);
1713 HOST_WIDE_INT fieldoffset = v->offset + loff;
1716 fieldoffset = v->offset;
1718 v = first_vi_for_offset (v, fieldoffset);
1719 /* If the access is outside of the variable we can ignore it. */
1725 if (v->may_have_pointers)
1727 /* If v is a global variable then this is an escape point. */
1728 if (v->is_global_var
1731 t = find (escaped_id);
1732 if (add_graph_edge (graph, t, rhs)
1733 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1734 bitmap_set_bit (changed, t);
1735 /* Enough to let rhs escape once. */
1739 if (v->is_special_var)
1743 if (add_graph_edge (graph, t, rhs)
1744 && bitmap_ior_into (get_varinfo (t)->solution, sol))
1745 bitmap_set_bit (changed, t);
1748 /* If the variable is not exactly at the requested offset
1749 we have to include the next one. */
1750 if (v->offset == (unsigned HOST_WIDE_INT)fieldoffset
1755 fieldoffset = v->offset;
1761 /* Handle a non-simple (simple meaning requires no iteration),
1762 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1765 do_complex_constraint (constraint_graph_t graph, constraint_t c, bitmap delta)
1767 if (c->lhs.type == DEREF)
1769 if (c->rhs.type == ADDRESSOF)
1776 do_ds_constraint (c, delta);
1779 else if (c->rhs.type == DEREF)
1782 if (!(get_varinfo (c->lhs.var)->is_special_var))
1783 do_sd_constraint (graph, c, delta);
1791 gcc_assert (c->rhs.type == SCALAR && c->lhs.type == SCALAR);
1792 solution = get_varinfo (c->rhs.var)->solution;
1793 tmp = get_varinfo (c->lhs.var)->solution;
1795 flag = set_union_with_increment (tmp, solution, c->rhs.offset);
1799 get_varinfo (c->lhs.var)->solution = tmp;
1800 bitmap_set_bit (changed, c->lhs.var);
1805 /* Initialize and return a new SCC info structure. */
1807 static struct scc_info *
1808 init_scc_info (size_t size)
1810 struct scc_info *si = XNEW (struct scc_info);
1813 si->current_index = 0;
1814 si->visited = sbitmap_alloc (size);
1815 sbitmap_zero (si->visited);
1816 si->deleted = sbitmap_alloc (size);
1817 sbitmap_zero (si->deleted);
1818 si->node_mapping = XNEWVEC (unsigned int, size);
1819 si->dfs = XCNEWVEC (unsigned int, size);
1821 for (i = 0; i < size; i++)
1822 si->node_mapping[i] = i;
1824 si->scc_stack = VEC_alloc (unsigned, heap, 1);
1828 /* Free an SCC info structure pointed to by SI */
1831 free_scc_info (struct scc_info *si)
1833 sbitmap_free (si->visited);
1834 sbitmap_free (si->deleted);
1835 free (si->node_mapping);
1837 VEC_free (unsigned, heap, si->scc_stack);
1842 /* Find indirect cycles in GRAPH that occur, using strongly connected
1843 components, and note them in the indirect cycles map.
1845 This technique comes from Ben Hardekopf and Calvin Lin,
1846 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1847 Lines of Code", submitted to PLDI 2007. */
1850 find_indirect_cycles (constraint_graph_t graph)
1853 unsigned int size = graph->size;
1854 struct scc_info *si = init_scc_info (size);
1856 for (i = 0; i < MIN (LAST_REF_NODE, size); i ++ )
1857 if (!TEST_BIT (si->visited, i) && find (i) == i)
1858 scc_visit (graph, si, i);
1863 /* Compute a topological ordering for GRAPH, and store the result in the
1864 topo_info structure TI. */
1867 compute_topo_order (constraint_graph_t graph,
1868 struct topo_info *ti)
1871 unsigned int size = graph->size;
1873 for (i = 0; i != size; ++i)
1874 if (!TEST_BIT (ti->visited, i) && find (i) == i)
1875 topo_visit (graph, ti, i);
1878 /* Structure used to for hash value numbering of pointer equivalence
1881 typedef struct equiv_class_label
1884 unsigned int equivalence_class;
1886 } *equiv_class_label_t;
1887 typedef const struct equiv_class_label *const_equiv_class_label_t;
1889 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1891 static htab_t pointer_equiv_class_table;
1893 /* A hashtable for mapping a bitmap of labels->location equivalence
1895 static htab_t location_equiv_class_table;
1897 /* Hash function for a equiv_class_label_t */
1900 equiv_class_label_hash (const void *p)
1902 const_equiv_class_label_t const ecl = (const_equiv_class_label_t) p;
1903 return ecl->hashcode;
1906 /* Equality function for two equiv_class_label_t's. */
1909 equiv_class_label_eq (const void *p1, const void *p2)
1911 const_equiv_class_label_t const eql1 = (const_equiv_class_label_t) p1;
1912 const_equiv_class_label_t const eql2 = (const_equiv_class_label_t) p2;
1913 return (eql1->hashcode == eql2->hashcode
1914 && bitmap_equal_p (eql1->labels, eql2->labels));
1917 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1921 equiv_class_lookup (htab_t table, bitmap labels)
1924 struct equiv_class_label ecl;
1926 ecl.labels = labels;
1927 ecl.hashcode = bitmap_hash (labels);
1929 slot = htab_find_slot_with_hash (table, &ecl,
1930 ecl.hashcode, NO_INSERT);
1934 return ((equiv_class_label_t) *slot)->equivalence_class;
1938 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1942 equiv_class_add (htab_t table, unsigned int equivalence_class,
1946 equiv_class_label_t ecl = XNEW (struct equiv_class_label);
1948 ecl->labels = labels;
1949 ecl->equivalence_class = equivalence_class;
1950 ecl->hashcode = bitmap_hash (labels);
1952 slot = htab_find_slot_with_hash (table, ecl,
1953 ecl->hashcode, INSERT);
1954 gcc_assert (!*slot);
1955 *slot = (void *) ecl;
1958 /* Perform offline variable substitution.
1960 This is a worst case quadratic time way of identifying variables
1961 that must have equivalent points-to sets, including those caused by
1962 static cycles, and single entry subgraphs, in the constraint graph.
1964 The technique is described in "Exploiting Pointer and Location
1965 Equivalence to Optimize Pointer Analysis. In the 14th International
1966 Static Analysis Symposium (SAS), August 2007." It is known as the
1967 "HU" algorithm, and is equivalent to value numbering the collapsed
1968 constraint graph including evaluating unions.
1970 The general method of finding equivalence classes is as follows:
1971 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1972 Initialize all non-REF nodes to be direct nodes.
1973 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1975 For each constraint containing the dereference, we also do the same
1978 We then compute SCC's in the graph and unify nodes in the same SCC,
1981 For each non-collapsed node x:
1982 Visit all unvisited explicit incoming edges.
1983 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1985 Lookup the equivalence class for pts(x).
1986 If we found one, equivalence_class(x) = found class.
1987 Otherwise, equivalence_class(x) = new class, and new_class is
1988 added to the lookup table.
1990 All direct nodes with the same equivalence class can be replaced
1991 with a single representative node.
1992 All unlabeled nodes (label == 0) are not pointers and all edges
1993 involving them can be eliminated.
1994 We perform these optimizations during rewrite_constraints
1996 In addition to pointer equivalence class finding, we also perform
1997 location equivalence class finding. This is the set of variables
1998 that always appear together in points-to sets. We use this to
1999 compress the size of the points-to sets. */
2001 /* Current maximum pointer equivalence class id. */
2002 static int pointer_equiv_class;
2004 /* Current maximum location equivalence class id. */
2005 static int location_equiv_class;
2007 /* Recursive routine to find strongly connected components in GRAPH,
2008 and label it's nodes with DFS numbers. */
2011 condense_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2015 unsigned int my_dfs;
2017 gcc_assert (si->node_mapping[n] == n);
2018 SET_BIT (si->visited, n);
2019 si->dfs[n] = si->current_index ++;
2020 my_dfs = si->dfs[n];
2022 /* Visit all the successors. */
2023 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2025 unsigned int w = si->node_mapping[i];
2027 if (TEST_BIT (si->deleted, w))
2030 if (!TEST_BIT (si->visited, w))
2031 condense_visit (graph, si, w);
2033 unsigned int t = si->node_mapping[w];
2034 unsigned int nnode = si->node_mapping[n];
2035 gcc_assert (nnode == n);
2037 if (si->dfs[t] < si->dfs[nnode])
2038 si->dfs[n] = si->dfs[t];
2042 /* Visit all the implicit predecessors. */
2043 EXECUTE_IF_IN_NONNULL_BITMAP (graph->implicit_preds[n], 0, i, bi)
2045 unsigned int w = si->node_mapping[i];
2047 if (TEST_BIT (si->deleted, w))
2050 if (!TEST_BIT (si->visited, w))
2051 condense_visit (graph, si, w);
2053 unsigned int t = si->node_mapping[w];
2054 unsigned int nnode = si->node_mapping[n];
2055 gcc_assert (nnode == n);
2057 if (si->dfs[t] < si->dfs[nnode])
2058 si->dfs[n] = si->dfs[t];
2062 /* See if any components have been identified. */
2063 if (si->dfs[n] == my_dfs)
2065 while (VEC_length (unsigned, si->scc_stack) != 0
2066 && si->dfs[VEC_last (unsigned, si->scc_stack)] >= my_dfs)
2068 unsigned int w = VEC_pop (unsigned, si->scc_stack);
2069 si->node_mapping[w] = n;
2071 if (!TEST_BIT (graph->direct_nodes, w))
2072 RESET_BIT (graph->direct_nodes, n);
2074 /* Unify our nodes. */
2075 if (graph->preds[w])
2077 if (!graph->preds[n])
2078 graph->preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2079 bitmap_ior_into (graph->preds[n], graph->preds[w]);
2081 if (graph->implicit_preds[w])
2083 if (!graph->implicit_preds[n])
2084 graph->implicit_preds[n] = BITMAP_ALLOC (&predbitmap_obstack);
2085 bitmap_ior_into (graph->implicit_preds[n],
2086 graph->implicit_preds[w]);
2088 if (graph->points_to[w])
2090 if (!graph->points_to[n])
2091 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2092 bitmap_ior_into (graph->points_to[n],
2093 graph->points_to[w]);
2096 SET_BIT (si->deleted, n);
2099 VEC_safe_push (unsigned, heap, si->scc_stack, n);
2102 /* Label pointer equivalences. */
2105 label_visit (constraint_graph_t graph, struct scc_info *si, unsigned int n)
2109 SET_BIT (si->visited, n);
2111 if (!graph->points_to[n])
2112 graph->points_to[n] = BITMAP_ALLOC (&predbitmap_obstack);
2114 /* Label and union our incoming edges's points to sets. */
2115 EXECUTE_IF_IN_NONNULL_BITMAP (graph->preds[n], 0, i, bi)
2117 unsigned int w = si->node_mapping[i];
2118 if (!TEST_BIT (si->visited, w))
2119 label_visit (graph, si, w);
2121 /* Skip unused edges */
2122 if (w == n || graph->pointer_label[w] == 0)
2125 if (graph->points_to[w])
2126 bitmap_ior_into(graph->points_to[n], graph->points_to[w]);
2128 /* Indirect nodes get fresh variables. */
2129 if (!TEST_BIT (graph->direct_nodes, n))
2130 bitmap_set_bit (graph->points_to[n], FIRST_REF_NODE + n);
2132 if (!bitmap_empty_p (graph->points_to[n]))
2134 unsigned int label = equiv_class_lookup (pointer_equiv_class_table,
2135 graph->points_to[n]);
2138 label = pointer_equiv_class++;
2139 equiv_class_add (pointer_equiv_class_table,
2140 label, graph->points_to[n]);
2142 graph->pointer_label[n] = label;
2146 /* Perform offline variable substitution, discovering equivalence
2147 classes, and eliminating non-pointer variables. */
2149 static struct scc_info *
2150 perform_var_substitution (constraint_graph_t graph)
2153 unsigned int size = graph->size;
2154 struct scc_info *si = init_scc_info (size);
2156 bitmap_obstack_initialize (&iteration_obstack);
2157 pointer_equiv_class_table = htab_create (511, equiv_class_label_hash,
2158 equiv_class_label_eq, free);
2159 location_equiv_class_table = htab_create (511, equiv_class_label_hash,
2160 equiv_class_label_eq, free);
2161 pointer_equiv_class = 1;
2162 location_equiv_class = 1;
2164 /* Condense the nodes, which means to find SCC's, count incoming
2165 predecessors, and unite nodes in SCC's. */
2166 for (i = 0; i < FIRST_REF_NODE; i++)
2167 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2168 condense_visit (graph, si, si->node_mapping[i]);
2170 sbitmap_zero (si->visited);
2171 /* Actually the label the nodes for pointer equivalences */
2172 for (i = 0; i < FIRST_REF_NODE; i++)
2173 if (!TEST_BIT (si->visited, si->node_mapping[i]))
2174 label_visit (graph, si, si->node_mapping[i]);
2176 /* Calculate location equivalence labels. */
2177 for (i = 0; i < FIRST_REF_NODE; i++)
2184 if (!graph->pointed_by[i])
2186 pointed_by = BITMAP_ALLOC (&iteration_obstack);
2188 /* Translate the pointed-by mapping for pointer equivalence
2190 EXECUTE_IF_SET_IN_BITMAP (graph->pointed_by[i], 0, j, bi)
2192 bitmap_set_bit (pointed_by,
2193 graph->pointer_label[si->node_mapping[j]]);
2195 /* The original pointed_by is now dead. */
2196 BITMAP_FREE (graph->pointed_by[i]);
2198 /* Look up the location equivalence label if one exists, or make
2200 label = equiv_class_lookup (location_equiv_class_table,
2204 label = location_equiv_class++;
2205 equiv_class_add (location_equiv_class_table,
2210 if (dump_file && (dump_flags & TDF_DETAILS))
2211 fprintf (dump_file, "Found location equivalence for node %s\n",
2212 get_varinfo (i)->name);
2213 BITMAP_FREE (pointed_by);
2215 graph->loc_label[i] = label;
2219 if (dump_file && (dump_flags & TDF_DETAILS))
2220 for (i = 0; i < FIRST_REF_NODE; i++)
2222 bool direct_node = TEST_BIT (graph->direct_nodes, i);
2224 "Equivalence classes for %s node id %d:%s are pointer: %d"
2226 direct_node ? "Direct node" : "Indirect node", i,
2227 get_varinfo (i)->name,
2228 graph->pointer_label[si->node_mapping[i]],
2229 graph->loc_label[si->node_mapping[i]]);
2232 /* Quickly eliminate our non-pointer variables. */
2234 for (i = 0; i < FIRST_REF_NODE; i++)
2236 unsigned int node = si->node_mapping[i];
2238 if (graph->pointer_label[node] == 0)
2240 if (dump_file && (dump_flags & TDF_DETAILS))
2242 "%s is a non-pointer variable, eliminating edges.\n",
2243 get_varinfo (node)->name);
2244 stats.nonpointer_vars++;
2245 clear_edges_for_node (graph, node);
2252 /* Free information that was only necessary for variable
2256 free_var_substitution_info (struct scc_info *si)
2259 free (graph->pointer_label);
2260 free (graph->loc_label);
2261 free (graph->pointed_by);
2262 free (graph->points_to);
2263 free (graph->eq_rep);
2264 sbitmap_free (graph->direct_nodes);
2265 htab_delete (pointer_equiv_class_table);
2266 htab_delete (location_equiv_class_table);
2267 bitmap_obstack_release (&iteration_obstack);
2270 /* Return an existing node that is equivalent to NODE, which has
2271 equivalence class LABEL, if one exists. Return NODE otherwise. */
2274 find_equivalent_node (constraint_graph_t graph,
2275 unsigned int node, unsigned int label)
2277 /* If the address version of this variable is unused, we can
2278 substitute it for anything else with the same label.
2279 Otherwise, we know the pointers are equivalent, but not the
2280 locations, and we can unite them later. */
2282 if (!bitmap_bit_p (graph->address_taken, node))
2284 gcc_assert (label < graph->size);
2286 if (graph->eq_rep[label] != -1)
2288 /* Unify the two variables since we know they are equivalent. */
2289 if (unite (graph->eq_rep[label], node))
2290 unify_nodes (graph, graph->eq_rep[label], node, false);
2291 return graph->eq_rep[label];
2295 graph->eq_rep[label] = node;
2296 graph->pe_rep[label] = node;
2301 gcc_assert (label < graph->size);
2302 graph->pe[node] = label;
2303 if (graph->pe_rep[label] == -1)
2304 graph->pe_rep[label] = node;
2310 /* Unite pointer equivalent but not location equivalent nodes in
2311 GRAPH. This may only be performed once variable substitution is
2315 unite_pointer_equivalences (constraint_graph_t graph)
2319 /* Go through the pointer equivalences and unite them to their
2320 representative, if they aren't already. */
2321 for (i = 0; i < FIRST_REF_NODE; i++)
2323 unsigned int label = graph->pe[i];
2326 int label_rep = graph->pe_rep[label];
2328 if (label_rep == -1)
2331 label_rep = find (label_rep);
2332 if (label_rep >= 0 && unite (label_rep, find (i)))
2333 unify_nodes (graph, label_rep, i, false);
2338 /* Move complex constraints to the GRAPH nodes they belong to. */
2341 move_complex_constraints (constraint_graph_t graph)
2346 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2350 struct constraint_expr lhs = c->lhs;
2351 struct constraint_expr rhs = c->rhs;
2353 if (lhs.type == DEREF)
2355 insert_into_complex (graph, lhs.var, c);
2357 else if (rhs.type == DEREF)
2359 if (!(get_varinfo (lhs.var)->is_special_var))
2360 insert_into_complex (graph, rhs.var, c);
2362 else if (rhs.type != ADDRESSOF && lhs.var > anything_id
2363 && (lhs.offset != 0 || rhs.offset != 0))
2365 insert_into_complex (graph, rhs.var, c);
2372 /* Optimize and rewrite complex constraints while performing
2373 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2374 result of perform_variable_substitution. */
2377 rewrite_constraints (constraint_graph_t graph,
2378 struct scc_info *si)
2384 for (j = 0; j < graph->size; j++)
2385 gcc_assert (find (j) == j);
2387 FOR_EACH_VEC_ELT (constraint_t, constraints, i, c)
2389 struct constraint_expr lhs = c->lhs;
2390 struct constraint_expr rhs = c->rhs;
2391 unsigned int lhsvar = find (lhs.var);
2392 unsigned int rhsvar = find (rhs.var);
2393 unsigned int lhsnode, rhsnode;
2394 unsigned int lhslabel, rhslabel;
2396 lhsnode = si->node_mapping[lhsvar];
2397 rhsnode = si->node_mapping[rhsvar];
2398 lhslabel = graph->pointer_label[lhsnode];
2399 rhslabel = graph->pointer_label[rhsnode];
2401 /* See if it is really a non-pointer variable, and if so, ignore
2405 if (dump_file && (dump_flags & TDF_DETAILS))
2408 fprintf (dump_file, "%s is a non-pointer variable,"
2409 "ignoring constraint:",
2410 get_varinfo (lhs.var)->name);
2411 dump_constraint (dump_file, c);
2412 fprintf (dump_file, "\n");
2414 VEC_replace (constraint_t, constraints, i, NULL);
2420 if (dump_file && (dump_flags & TDF_DETAILS))
2423 fprintf (dump_file, "%s is a non-pointer variable,"
2424 "ignoring constraint:",
2425 get_varinfo (rhs.var)->name);
2426 dump_constraint (dump_file, c);
2427 fprintf (dump_file, "\n");
2429 VEC_replace (constraint_t, constraints, i, NULL);
2433 lhsvar = find_equivalent_node (graph, lhsvar, lhslabel);
2434 rhsvar = find_equivalent_node (graph, rhsvar, rhslabel);
2435 c->lhs.var = lhsvar;
2436 c->rhs.var = rhsvar;
2441 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2442 part of an SCC, false otherwise. */
2445 eliminate_indirect_cycles (unsigned int node)
2447 if (graph->indirect_cycles[node] != -1
2448 && !bitmap_empty_p (get_varinfo (node)->solution))
2451 VEC(unsigned,heap) *queue = NULL;
2453 unsigned int to = find (graph->indirect_cycles[node]);
2456 /* We can't touch the solution set and call unify_nodes
2457 at the same time, because unify_nodes is going to do
2458 bitmap unions into it. */
2460 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node)->solution, 0, i, bi)
2462 if (find (i) == i && i != to)
2465 VEC_safe_push (unsigned, heap, queue, i);
2470 VEC_iterate (unsigned, queue, queuepos, i);
2473 unify_nodes (graph, to, i, true);
2475 VEC_free (unsigned, heap, queue);
2481 /* Solve the constraint graph GRAPH using our worklist solver.
2482 This is based on the PW* family of solvers from the "Efficient Field
2483 Sensitive Pointer Analysis for C" paper.
2484 It works by iterating over all the graph nodes, processing the complex
2485 constraints and propagating the copy constraints, until everything stops
2486 changed. This corresponds to steps 6-8 in the solving list given above. */
2489 solve_graph (constraint_graph_t graph)
2491 unsigned int size = graph->size;
2495 changed = BITMAP_ALLOC (NULL);
2497 /* Mark all initial non-collapsed nodes as changed. */
2498 for (i = 0; i < size; i++)
2500 varinfo_t ivi = get_varinfo (i);
2501 if (find (i) == i && !bitmap_empty_p (ivi->solution)
2502 && ((graph->succs[i] && !bitmap_empty_p (graph->succs[i]))
2503 || VEC_length (constraint_t, graph->complex[i]) > 0))
2504 bitmap_set_bit (changed, i);
2507 /* Allocate a bitmap to be used to store the changed bits. */
2508 pts = BITMAP_ALLOC (&pta_obstack);
2510 while (!bitmap_empty_p (changed))
2513 struct topo_info *ti = init_topo_info ();
2516 bitmap_obstack_initialize (&iteration_obstack);
2518 compute_topo_order (graph, ti);
2520 while (VEC_length (unsigned, ti->topo_order) != 0)
2523 i = VEC_pop (unsigned, ti->topo_order);
2525 /* If this variable is not a representative, skip it. */
2529 /* In certain indirect cycle cases, we may merge this
2530 variable to another. */
2531 if (eliminate_indirect_cycles (i) && find (i) != i)
2534 /* If the node has changed, we need to process the
2535 complex constraints and outgoing edges again. */
2536 if (bitmap_clear_bit (changed, i))
2541 VEC(constraint_t,heap) *complex = graph->complex[i];
2542 varinfo_t vi = get_varinfo (i);
2543 bool solution_empty;
2545 /* Compute the changed set of solution bits. */
2546 if (vi->oldsolution)
2547 bitmap_and_compl (pts, vi->solution, vi->oldsolution);
2549 bitmap_copy (pts, vi->solution);
2551 if (bitmap_empty_p (pts))
2554 if (vi->oldsolution)
2555 bitmap_ior_into (vi->oldsolution, pts);
2558 vi->oldsolution = BITMAP_ALLOC (&oldpta_obstack);
2559 bitmap_copy (vi->oldsolution, pts);
2562 solution = vi->solution;
2563 solution_empty = bitmap_empty_p (solution);
2565 /* Process the complex constraints */
2566 FOR_EACH_VEC_ELT (constraint_t, complex, j, c)
2568 /* XXX: This is going to unsort the constraints in
2569 some cases, which will occasionally add duplicate
2570 constraints during unification. This does not
2571 affect correctness. */
2572 c->lhs.var = find (c->lhs.var);
2573 c->rhs.var = find (c->rhs.var);
2575 /* The only complex constraint that can change our
2576 solution to non-empty, given an empty solution,
2577 is a constraint where the lhs side is receiving
2578 some set from elsewhere. */
2579 if (!solution_empty || c->lhs.type != DEREF)
2580 do_complex_constraint (graph, c, pts);
2583 solution_empty = bitmap_empty_p (solution);
2585 if (!solution_empty)
2588 unsigned eff_escaped_id = find (escaped_id);
2590 /* Propagate solution to all successors. */
2591 EXECUTE_IF_IN_NONNULL_BITMAP (graph->succs[i],
2597 unsigned int to = find (j);
2598 tmp = get_varinfo (to)->solution;
2601 /* Don't try to propagate to ourselves. */
2605 /* If we propagate from ESCAPED use ESCAPED as
2607 if (i == eff_escaped_id)
2608 flag = bitmap_set_bit (tmp, escaped_id);
2610 flag = set_union_with_increment (tmp, pts, 0);
2614 get_varinfo (to)->solution = tmp;
2615 bitmap_set_bit (changed, to);
2621 free_topo_info (ti);
2622 bitmap_obstack_release (&iteration_obstack);
2626 BITMAP_FREE (changed);
2627 bitmap_obstack_release (&oldpta_obstack);
2630 /* Map from trees to variable infos. */
2631 static struct pointer_map_t *vi_for_tree;
2634 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2637 insert_vi_for_tree (tree t, varinfo_t vi)
2639 void **slot = pointer_map_insert (vi_for_tree, t);
2641 gcc_assert (*slot == NULL);
2645 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2646 exist in the map, return NULL, otherwise, return the varinfo we found. */
2649 lookup_vi_for_tree (tree t)
2651 void **slot = pointer_map_contains (vi_for_tree, t);
2655 return (varinfo_t) *slot;
2658 /* Return a printable name for DECL */
2661 alias_get_name (tree decl)
2665 int num_printed = 0;
2667 if (DECL_ASSEMBLER_NAME_SET_P (decl))
2668 res = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
2670 res= get_name (decl);
2678 if (TREE_CODE (decl) == SSA_NAME)
2680 num_printed = asprintf (&temp, "%s_%u",
2681 alias_get_name (SSA_NAME_VAR (decl)),
2682 SSA_NAME_VERSION (decl));
2684 else if (DECL_P (decl))
2686 num_printed = asprintf (&temp, "D.%u", DECL_UID (decl));
2688 if (num_printed > 0)
2690 res = ggc_strdup (temp);
2696 /* Find the variable id for tree T in the map.
2697 If T doesn't exist in the map, create an entry for it and return it. */
2700 get_vi_for_tree (tree t)
2702 void **slot = pointer_map_contains (vi_for_tree, t);
2704 return get_varinfo (create_variable_info_for (t, alias_get_name (t)));
2706 return (varinfo_t) *slot;
2709 /* Get a scalar constraint expression for a new temporary variable. */
2711 static struct constraint_expr
2712 new_scalar_tmp_constraint_exp (const char *name)
2714 struct constraint_expr tmp;
2717 vi = new_var_info (NULL_TREE, name);
2721 vi->is_full_var = 1;
2730 /* Get a constraint expression vector from an SSA_VAR_P node.
2731 If address_p is true, the result will be taken its address of. */
2734 get_constraint_for_ssa_var (tree t, VEC(ce_s, heap) **results, bool address_p)
2736 struct constraint_expr cexpr;
2739 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2740 gcc_assert (SSA_VAR_P (t) || DECL_P (t));
2742 /* For parameters, get at the points-to set for the actual parm
2744 if (TREE_CODE (t) == SSA_NAME
2745 && (TREE_CODE (SSA_NAME_VAR (t)) == PARM_DECL
2746 || TREE_CODE (SSA_NAME_VAR (t)) == RESULT_DECL)
2747 && SSA_NAME_IS_DEFAULT_DEF (t))
2749 get_constraint_for_ssa_var (SSA_NAME_VAR (t), results, address_p);
2753 /* For global variables resort to the alias target. */
2754 if (TREE_CODE (t) == VAR_DECL
2755 && (TREE_STATIC (t) || DECL_EXTERNAL (t)))
2757 struct varpool_node *node = varpool_get_node (t);
2758 if (node && node->alias)
2760 node = varpool_variable_node (node, NULL);
2765 vi = get_vi_for_tree (t);
2767 cexpr.type = SCALAR;
2769 /* If we determine the result is "anything", and we know this is readonly,
2770 say it points to readonly memory instead. */
2771 if (cexpr.var == anything_id && TREE_READONLY (t))
2774 cexpr.type = ADDRESSOF;
2775 cexpr.var = readonly_id;
2778 /* If we are not taking the address of the constraint expr, add all
2779 sub-fiels of the variable as well. */
2781 && !vi->is_full_var)
2783 for (; vi; vi = vi->next)
2786 VEC_safe_push (ce_s, heap, *results, &cexpr);
2791 VEC_safe_push (ce_s, heap, *results, &cexpr);
2794 /* Process constraint T, performing various simplifications and then
2795 adding it to our list of overall constraints. */
2798 process_constraint (constraint_t t)
2800 struct constraint_expr rhs = t->rhs;
2801 struct constraint_expr lhs = t->lhs;
2803 gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
2804 gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
2806 /* If we didn't get any useful constraint from the lhs we get
2807 &ANYTHING as fallback from get_constraint_for. Deal with
2808 it here by turning it into *ANYTHING. */
2809 if (lhs.type == ADDRESSOF
2810 && lhs.var == anything_id)
2813 /* ADDRESSOF on the lhs is invalid. */
2814 gcc_assert (lhs.type != ADDRESSOF);
2816 /* We shouldn't add constraints from things that cannot have pointers.
2817 It's not completely trivial to avoid in the callers, so do it here. */
2818 if (rhs.type != ADDRESSOF
2819 && !get_varinfo (rhs.var)->may_have_pointers)
2822 /* Likewise adding to the solution of a non-pointer var isn't useful. */
2823 if (!get_varinfo (lhs.var)->may_have_pointers)
2826 /* This can happen in our IR with things like n->a = *p */
2827 if (rhs.type == DEREF && lhs.type == DEREF && rhs.var != anything_id)
2829 /* Split into tmp = *rhs, *lhs = tmp */
2830 struct constraint_expr tmplhs;
2831 tmplhs = new_scalar_tmp_constraint_exp ("doubledereftmp");
2832 process_constraint (new_constraint (tmplhs, rhs));
2833 process_constraint (new_constraint (lhs, tmplhs));
2835 else if (rhs.type == ADDRESSOF && lhs.type == DEREF)
2837 /* Split into tmp = &rhs, *lhs = tmp */
2838 struct constraint_expr tmplhs;
2839 tmplhs = new_scalar_tmp_constraint_exp ("derefaddrtmp");
2840 process_constraint (new_constraint (tmplhs, rhs));
2841 process_constraint (new_constraint (lhs, tmplhs));
2845 gcc_assert (rhs.type != ADDRESSOF || rhs.offset == 0);
2846 VEC_safe_push (constraint_t, heap, constraints, t);
2851 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2854 static HOST_WIDE_INT
2855 bitpos_of_field (const tree fdecl)
2857 if (!host_integerp (DECL_FIELD_OFFSET (fdecl), 0)
2858 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl), 0))
2861 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl)) * BITS_PER_UNIT
2862 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl)));
2866 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2867 resulting constraint expressions in *RESULTS. */
2870 get_constraint_for_ptr_offset (tree ptr, tree offset,
2871 VEC (ce_s, heap) **results)
2873 struct constraint_expr c;
2875 HOST_WIDE_INT rhsoffset;
2877 /* If we do not do field-sensitive PTA adding offsets to pointers
2878 does not change the points-to solution. */
2879 if (!use_field_sensitive)
2881 get_constraint_for_rhs (ptr, results);
2885 /* If the offset is not a non-negative integer constant that fits
2886 in a HOST_WIDE_INT, we have to fall back to a conservative
2887 solution which includes all sub-fields of all pointed-to
2888 variables of ptr. */
2889 if (offset == NULL_TREE
2890 || TREE_CODE (offset) != INTEGER_CST)
2891 rhsoffset = UNKNOWN_OFFSET;
2894 /* Sign-extend the offset. */
2896 = double_int_sext (tree_to_double_int (offset),
2897 TYPE_PRECISION (TREE_TYPE (offset)));
2898 if (!double_int_fits_in_shwi_p (soffset))
2899 rhsoffset = UNKNOWN_OFFSET;
2902 /* Make sure the bit-offset also fits. */
2903 HOST_WIDE_INT rhsunitoffset = soffset.low;
2904 rhsoffset = rhsunitoffset * BITS_PER_UNIT;
2905 if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
2906 rhsoffset = UNKNOWN_OFFSET;
2910 get_constraint_for_rhs (ptr, results);
2914 /* As we are eventually appending to the solution do not use
2915 VEC_iterate here. */
2916 n = VEC_length (ce_s, *results);
2917 for (j = 0; j < n; j++)
2920 c = *VEC_index (ce_s, *results, j);
2921 curr = get_varinfo (c.var);
2923 if (c.type == ADDRESSOF
2924 /* If this varinfo represents a full variable just use it. */
2925 && curr->is_full_var)
2927 else if (c.type == ADDRESSOF
2928 /* If we do not know the offset add all subfields. */
2929 && rhsoffset == UNKNOWN_OFFSET)
2931 varinfo_t temp = lookup_vi_for_tree (curr->decl);
2934 struct constraint_expr c2;
2936 c2.type = ADDRESSOF;
2938 if (c2.var != c.var)
2939 VEC_safe_push (ce_s, heap, *results, &c2);
2944 else if (c.type == ADDRESSOF)
2947 unsigned HOST_WIDE_INT offset = curr->offset + rhsoffset;
2949 /* Search the sub-field which overlaps with the
2950 pointed-to offset. If the result is outside of the variable
2951 we have to provide a conservative result, as the variable is
2952 still reachable from the resulting pointer (even though it
2953 technically cannot point to anything). The last and first
2954 sub-fields are such conservative results.
2955 ??? If we always had a sub-field for &object + 1 then
2956 we could represent this in a more precise way. */
2958 && curr->offset < offset)
2960 temp = first_or_preceding_vi_for_offset (curr, offset);
2962 /* If the found variable is not exactly at the pointed to
2963 result, we have to include the next variable in the
2964 solution as well. Otherwise two increments by offset / 2
2965 do not result in the same or a conservative superset
2967 if (temp->offset != offset
2968 && temp->next != NULL)
2970 struct constraint_expr c2;
2971 c2.var = temp->next->id;
2972 c2.type = ADDRESSOF;
2974 VEC_safe_push (ce_s, heap, *results, &c2);
2980 c.offset = rhsoffset;
2982 VEC_replace (ce_s, *results, j, &c);
2987 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2988 If address_p is true the result will be taken its address of.
2989 If lhs_p is true then the constraint expression is assumed to be used
2993 get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
2994 bool address_p, bool lhs_p)
2997 HOST_WIDE_INT bitsize = -1;
2998 HOST_WIDE_INT bitmaxsize = -1;
2999 HOST_WIDE_INT bitpos;
3001 struct constraint_expr *result;
3003 /* Some people like to do cute things like take the address of
3006 while (handled_component_p (forzero)
3007 || INDIRECT_REF_P (forzero)
3008 || TREE_CODE (forzero) == MEM_REF)
3009 forzero = TREE_OPERAND (forzero, 0);
3011 if (CONSTANT_CLASS_P (forzero) && integer_zerop (forzero))
3013 struct constraint_expr temp;
3016 temp.var = integer_id;
3018 VEC_safe_push (ce_s, heap, *results, &temp);
3022 /* Handle type-punning through unions. If we are extracting a pointer
3023 from a union via a possibly type-punning access that pointer
3024 points to anything, similar to a conversion of an integer to
3030 TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
3031 u = TREE_OPERAND (u, 0))
3032 if (TREE_CODE (u) == COMPONENT_REF
3033 && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
3035 struct constraint_expr temp;
3038 temp.var = anything_id;
3039 temp.type = ADDRESSOF;
3040 VEC_safe_push (ce_s, heap, *results, &temp);
3045 t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
3047 /* Pretend to take the address of the base, we'll take care of
3048 adding the required subset of sub-fields below. */
3049 get_constraint_for_1 (t, results, true, lhs_p);
3050 gcc_assert (VEC_length (ce_s, *results) == 1);
3051 result = VEC_last (ce_s, *results);
3053 if (result->type == SCALAR
3054 && get_varinfo (result->var)->is_full_var)
3055 /* For single-field vars do not bother about the offset. */
3057 else if (result->type == SCALAR)
3059 /* In languages like C, you can access one past the end of an
3060 array. You aren't allowed to dereference it, so we can
3061 ignore this constraint. When we handle pointer subtraction,
3062 we may have to do something cute here. */
3064 if ((unsigned HOST_WIDE_INT)bitpos < get_varinfo (result->var)->fullsize
3067 /* It's also not true that the constraint will actually start at the
3068 right offset, it may start in some padding. We only care about
3069 setting the constraint to the first actual field it touches, so
3071 struct constraint_expr cexpr = *result;
3073 VEC_pop (ce_s, *results);
3075 for (curr = get_varinfo (cexpr.var); curr; curr = curr->next)
3077 if (ranges_overlap_p (curr->offset, curr->size,
3078 bitpos, bitmaxsize))
3080 cexpr.var = curr->id;
3081 VEC_safe_push (ce_s, heap, *results, &cexpr);
3086 /* If we are going to take the address of this field then
3087 to be able to compute reachability correctly add at least
3088 the last field of the variable. */
3090 && VEC_length (ce_s, *results) == 0)
3092 curr = get_varinfo (cexpr.var);
3093 while (curr->next != NULL)
3095 cexpr.var = curr->id;
3096 VEC_safe_push (ce_s, heap, *results, &cexpr);
3098 else if (VEC_length (ce_s, *results) == 0)
3099 /* Assert that we found *some* field there. The user couldn't be
3100 accessing *only* padding. */
3101 /* Still the user could access one past the end of an array
3102 embedded in a struct resulting in accessing *only* padding. */
3103 /* Or accessing only padding via type-punning to a type
3104 that has a filed just in padding space. */
3106 cexpr.type = SCALAR;
3107 cexpr.var = anything_id;
3109 VEC_safe_push (ce_s, heap, *results, &cexpr);
3112 else if (bitmaxsize == 0)
3114 if (dump_file && (dump_flags & TDF_DETAILS))
3115 fprintf (dump_file, "Access to zero-sized part of variable,"
3119 if (dump_file && (dump_flags & TDF_DETAILS))
3120 fprintf (dump_file, "Access to past the end of variable, ignoring\n");
3122 else if (result->type == DEREF)
3124 /* If we do not know exactly where the access goes say so. Note
3125 that only for non-structure accesses we know that we access
3126 at most one subfiled of any variable. */
3128 || bitsize != bitmaxsize
3129 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t))
3130 || result->offset == UNKNOWN_OFFSET)
3131 result->offset = UNKNOWN_OFFSET;
3133 result->offset += bitpos;
3135 else if (result->type == ADDRESSOF)
3137 /* We can end up here for component references on a
3138 VIEW_CONVERT_EXPR <>(&foobar). */
3139 result->type = SCALAR;
3140 result->var = anything_id;
3148 /* Dereference the constraint expression CONS, and return the result.
3149 DEREF (ADDRESSOF) = SCALAR
3150 DEREF (SCALAR) = DEREF
3151 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3152 This is needed so that we can handle dereferencing DEREF constraints. */
3155 do_deref (VEC (ce_s, heap) **constraints)
3157 struct constraint_expr *c;
3160 FOR_EACH_VEC_ELT (ce_s, *constraints, i, c)
3162 if (c->type == SCALAR)
3164 else if (c->type == ADDRESSOF)
3166 else if (c->type == DEREF)
3168 struct constraint_expr tmplhs;
3169 tmplhs = new_scalar_tmp_constraint_exp ("dereftmp");
3170 process_constraint (new_constraint (tmplhs, *c));
3171 c->var = tmplhs.var;
3178 /* Given a tree T, return the constraint expression for taking the
3182 get_constraint_for_address_of (tree t, VEC (ce_s, heap) **results)
3184 struct constraint_expr *c;
3187 get_constraint_for_1 (t, results, true, true);
3189 FOR_EACH_VEC_ELT (ce_s, *results, i, c)
3191 if (c->type == DEREF)
3194 c->type = ADDRESSOF;
3198 /* Given a tree T, return the constraint expression for it. */
3201 get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p,
3204 struct constraint_expr temp;
3206 /* x = integer is all glommed to a single variable, which doesn't
3207 point to anything by itself. That is, of course, unless it is an
3208 integer constant being treated as a pointer, in which case, we
3209 will return that this is really the addressof anything. This
3210 happens below, since it will fall into the default case. The only
3211 case we know something about an integer treated like a pointer is
3212 when it is the NULL pointer, and then we just say it points to
3215 Do not do that if -fno-delete-null-pointer-checks though, because
3216 in that case *NULL does not fail, so it _should_ alias *anything.
3217 It is not worth adding a new option or renaming the existing one,
3218 since this case is relatively obscure. */
3219 if ((TREE_CODE (t) == INTEGER_CST
3220 && integer_zerop (t))
3221 /* The only valid CONSTRUCTORs in gimple with pointer typed
3222 elements are zero-initializer. But in IPA mode we also
3223 process global initializers, so verify at least. */
3224 || (TREE_CODE (t) == CONSTRUCTOR
3225 && CONSTRUCTOR_NELTS (t) == 0))
3227 if (flag_delete_null_pointer_checks)
3228 temp.var = nothing_id;
3230 temp.var = nonlocal_id;
3231 temp.type = ADDRESSOF;
3233 VEC_safe_push (ce_s, heap, *results, &temp);
3237 /* String constants are read-only. */
3238 if (TREE_CODE (t) == STRING_CST)
3240 temp.var = readonly_id;
3243 VEC_safe_push (ce_s, heap, *results, &temp);
3247 switch (TREE_CODE_CLASS (TREE_CODE (t)))
3249 case tcc_expression:
3251 switch (TREE_CODE (t))
3254 get_constraint_for_address_of (TREE_OPERAND (t, 0), results);
3262 switch (TREE_CODE (t))
3266 struct constraint_expr cs;
3268 get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
3269 TREE_OPERAND (t, 1), results);
3272 /* If we are not taking the address then make sure to process
3273 all subvariables we might access. */
3277 cs = *VEC_last (ce_s, *results);
3278 if (cs.type == DEREF)
3280 /* For dereferences this means we have to defer it
3282 VEC_last (ce_s, *results)->offset = UNKNOWN_OFFSET;
3285 if (cs.type != SCALAR)
3288 vi = get_varinfo (cs.var);
3290 if (!vi->is_full_var
3293 unsigned HOST_WIDE_INT size;
3294 if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
3295 size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
3298 for (; curr; curr = curr->next)
3300 if (curr->offset - vi->offset < size)
3303 VEC_safe_push (ce_s, heap, *results, &cs);
3312 case ARRAY_RANGE_REF:
3314 get_constraint_for_component_ref (t, results, address_p, lhs_p);
3316 case VIEW_CONVERT_EXPR:
3317 get_constraint_for_1 (TREE_OPERAND (t, 0), results, address_p,
3320 /* We are missing handling for TARGET_MEM_REF here. */
3325 case tcc_exceptional:
3327 switch (TREE_CODE (t))
3331 get_constraint_for_ssa_var (t, results, address_p);
3338 VEC (ce_s, heap) *tmp = NULL;
3339 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), i, val)
3341 struct constraint_expr *rhsp;
3343 get_constraint_for_1 (val, &tmp, address_p, lhs_p);
3344 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
3345 VEC_safe_push (ce_s, heap, *results, rhsp);
3346 VEC_truncate (ce_s, tmp, 0);
3348 VEC_free (ce_s, heap, tmp);
3349 /* We do not know whether the constructor was complete,
3350 so technically we have to add &NOTHING or &ANYTHING
3351 like we do for an empty constructor as well. */
3358 case tcc_declaration:
3360 get_constraint_for_ssa_var (t, results, address_p);
3365 /* We cannot refer to automatic variables through constants. */
3366 temp.type = ADDRESSOF;
3367 temp.var = nonlocal_id;
3369 VEC_safe_push (ce_s, heap, *results, &temp);
3375 /* The default fallback is a constraint from anything. */
3376 temp.type = ADDRESSOF;
3377 temp.var = anything_id;
3379 VEC_safe_push (ce_s, heap, *results, &temp);
3382 /* Given a gimple tree T, return the constraint expression vector for it. */
3385 get_constraint_for (tree t, VEC (ce_s, heap) **results)
3387 gcc_assert (VEC_length (ce_s, *results) == 0);
3389 get_constraint_for_1 (t, results, false, true);
3392 /* Given a gimple tree T, return the constraint expression vector for it
3393 to be used as the rhs of a constraint. */
3396 get_constraint_for_rhs (tree t, VEC (ce_s, heap) **results)
3398 gcc_assert (VEC_length (ce_s, *results) == 0);
3400 get_constraint_for_1 (t, results, false, false);
3404 /* Efficiently generates constraints from all entries in *RHSC to all
3405 entries in *LHSC. */
3408 process_all_all_constraints (VEC (ce_s, heap) *lhsc, VEC (ce_s, heap) *rhsc)
3410 struct constraint_expr *lhsp, *rhsp;
3413 if (VEC_length (ce_s, lhsc) <= 1
3414 || VEC_length (ce_s, rhsc) <= 1)
3416 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3417 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
3418 process_constraint (new_constraint (*lhsp, *rhsp));
3422 struct constraint_expr tmp;
3423 tmp = new_scalar_tmp_constraint_exp ("allalltmp");
3424 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
3425 process_constraint (new_constraint (tmp, *rhsp));
3426 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
3427 process_constraint (new_constraint (*lhsp, tmp));
3431 /* Handle aggregate copies by expanding into copies of the respective
3432 fields of the structures. */
3435 do_structure_copy (tree lhsop, tree rhsop)
3437 struct constraint_expr *lhsp, *rhsp;
3438 VEC (ce_s, heap) *lhsc = NULL, *rhsc = NULL;
3441 get_constraint_for (lhsop, &lhsc);
3442 get_constraint_for_rhs (rhsop, &rhsc);
3443 lhsp = VEC_index (ce_s, lhsc, 0);
3444 rhsp = VEC_index (ce_s, rhsc, 0);
3445 if (lhsp->type == DEREF
3446 || (lhsp->type == ADDRESSOF && lhsp->var == anything_id)
3447 || rhsp->type == DEREF)
3449 if (lhsp->type == DEREF)
3451 gcc_assert (VEC_length (ce_s, lhsc) == 1);
3452 lhsp->offset = UNKNOWN_OFFSET;
3454 if (rhsp->type == DEREF)
3456 gcc_assert (VEC_length (ce_s, rhsc) == 1);
3457 rhsp->offset = UNKNOWN_OFFSET;
3459 process_all_all_constraints (lhsc, rhsc);
3461 else if (lhsp->type == SCALAR
3462 && (rhsp->type == SCALAR
3463 || rhsp->type == ADDRESSOF))
3465 HOST_WIDE_INT lhssize, lhsmaxsize, lhsoffset;
3466 HOST_WIDE_INT rhssize, rhsmaxsize, rhsoffset;
3468 get_ref_base_and_extent (lhsop, &lhsoffset, &lhssize, &lhsmaxsize);
3469 get_ref_base_and_extent (rhsop, &rhsoffset, &rhssize, &rhsmaxsize);
3470 for (j = 0; VEC_iterate (ce_s, lhsc, j, lhsp);)
3472 varinfo_t lhsv, rhsv;
3473 rhsp = VEC_index (ce_s, rhsc, k);
3474 lhsv = get_varinfo (lhsp->var);
3475 rhsv = get_varinfo (rhsp->var);
3476 if (lhsv->may_have_pointers
3477 && (lhsv->is_full_var
3478 || rhsv->is_full_var
3479 || ranges_overlap_p (lhsv->offset + rhsoffset, lhsv->size,
3480 rhsv->offset + lhsoffset, rhsv->size)))
3481 process_constraint (new_constraint (*lhsp, *rhsp));
3482 if (!rhsv->is_full_var
3483 && (lhsv->is_full_var
3484 || (lhsv->offset + rhsoffset + lhsv->size
3485 > rhsv->offset + lhsoffset + rhsv->size)))
3488 if (k >= VEC_length (ce_s, rhsc))
3498 VEC_free (ce_s, heap, lhsc);
3499 VEC_free (ce_s, heap, rhsc);
3502 /* Create constraints ID = { rhsc }. */
3505 make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
3507 struct constraint_expr *c;
3508 struct constraint_expr includes;
3512 includes.offset = 0;
3513 includes.type = SCALAR;
3515 FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
3516 process_constraint (new_constraint (includes, *c));
3519 /* Create a constraint ID = OP. */
3522 make_constraint_to (unsigned id, tree op)
3524 VEC(ce_s, heap) *rhsc = NULL;
3525 get_constraint_for_rhs (op, &rhsc);
3526 make_constraints_to (id, rhsc);
3527 VEC_free (ce_s, heap, rhsc);
3530 /* Create a constraint ID = &FROM. */
3533 make_constraint_from (varinfo_t vi, int from)
3535 struct constraint_expr lhs, rhs;
3543 rhs.type = ADDRESSOF;
3544 process_constraint (new_constraint (lhs, rhs));
3547 /* Create a constraint ID = FROM. */
3550 make_copy_constraint (varinfo_t vi, int from)
3552 struct constraint_expr lhs, rhs;
3561 process_constraint (new_constraint (lhs, rhs));
3564 /* Make constraints necessary to make OP escape. */
3567 make_escape_constraint (tree op)
3569 make_constraint_to (escaped_id, op);
3572 /* Add constraints to that the solution of VI is transitively closed. */
3575 make_transitive_closure_constraints (varinfo_t vi)
3577 struct constraint_expr lhs, rhs;
3586 process_constraint (new_constraint (lhs, rhs));
3588 /* VAR = VAR + UNKNOWN; */
3594 rhs.offset = UNKNOWN_OFFSET;
3595 process_constraint (new_constraint (lhs, rhs));
3598 /* Temporary storage for fake var decls. */
3599 struct obstack fake_var_decl_obstack;
3601 /* Build a fake VAR_DECL acting as referrer to a DECL_UID. */
3604 build_fake_var_decl (tree type)
3606 tree decl = (tree) XOBNEW (&fake_var_decl_obstack, struct tree_var_decl);
3607 memset (decl, 0, sizeof (struct tree_var_decl));
3608 TREE_SET_CODE (decl, VAR_DECL);
3609 TREE_TYPE (decl) = type;
3610 DECL_UID (decl) = allocate_decl_uid ();
3611 SET_DECL_PT_UID (decl, -1);
3612 layout_decl (decl, 0);
3616 /* Create a new artificial heap variable with NAME.
3617 Return the created variable. */
3620 make_heapvar (const char *name)
3625 heapvar = build_fake_var_decl (ptr_type_node);
3626 DECL_EXTERNAL (heapvar) = 1;
3628 vi = new_var_info (heapvar, name);
3629 vi->is_artificial_var = true;
3630 vi->is_heap_var = true;
3631 vi->is_unknown_size_var = true;
3635 vi->is_full_var = true;
3636 insert_vi_for_tree (heapvar, vi);
3641 /* Create a new artificial heap variable with NAME and make a
3642 constraint from it to LHS. Set flags according to a tag used
3643 for tracking restrict pointers. */
3646 make_constraint_from_restrict (varinfo_t lhs, const char *name)
3648 varinfo_t vi = make_heapvar (name);
3649 vi->is_global_var = 1;
3650 vi->may_have_pointers = 1;
3651 make_constraint_from (lhs, vi->id);
3655 /* Create a new artificial heap variable with NAME and make a
3656 constraint from it to LHS. Set flags according to a tag used
3657 for tracking restrict pointers and make the artificial heap
3658 point to global memory. */
3661 make_constraint_from_global_restrict (varinfo_t lhs, const char *name)
3663 varinfo_t vi = make_constraint_from_restrict (lhs, name);
3664 make_copy_constraint (vi, nonlocal_id);
3668 /* In IPA mode there are varinfos for different aspects of reach
3669 function designator. One for the points-to set of the return
3670 value, one for the variables that are clobbered by the function,
3671 one for its uses and one for each parameter (including a single
3672 glob for remaining variadic arguments). */
3674 enum { fi_clobbers = 1, fi_uses = 2,
3675 fi_static_chain = 3, fi_result = 4, fi_parm_base = 5 };
3677 /* Get a constraint for the requested part of a function designator FI
3678 when operating in IPA mode. */
3680 static struct constraint_expr
3681 get_function_part_constraint (varinfo_t fi, unsigned part)
3683 struct constraint_expr c;
3685 gcc_assert (in_ipa_mode);
3687 if (fi->id == anything_id)
3689 /* ??? We probably should have a ANYFN special variable. */
3690 c.var = anything_id;
3694 else if (TREE_CODE (fi->decl) == FUNCTION_DECL)
3696 varinfo_t ai = first_vi_for_offset (fi, part);
3700 c.var = anything_id;
3714 /* For non-IPA mode, generate constraints necessary for a call on the
3718 handle_rhs_call (gimple stmt, VEC(ce_s, heap) **results)
3720 struct constraint_expr rhsc;
3722 bool returns_uses = false;
3724 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3726 tree arg = gimple_call_arg (stmt, i);
3727 int flags = gimple_call_arg_flags (stmt, i);
3729 /* If the argument is not used we can ignore it. */
3730 if (flags & EAF_UNUSED)
3733 /* As we compute ESCAPED context-insensitive we do not gain
3734 any precision with just EAF_NOCLOBBER but not EAF_NOESCAPE
3735 set. The argument would still get clobbered through the
3737 ??? We might get away with less (and more precise) constraints
3738 if using a temporary for transitively closing things. */
3739 if ((flags & EAF_NOCLOBBER)
3740 && (flags & EAF_NOESCAPE))
3742 varinfo_t uses = get_call_use_vi (stmt);
3743 if (!(flags & EAF_DIRECT))
3744 make_transitive_closure_constraints (uses);
3745 make_constraint_to (uses->id, arg);
3746 returns_uses = true;
3748 else if (flags & EAF_NOESCAPE)
3750 varinfo_t uses = get_call_use_vi (stmt);
3751 varinfo_t clobbers = get_call_clobber_vi (stmt);
3752 if (!(flags & EAF_DIRECT))
3754 make_transitive_closure_constraints (uses);
3755 make_transitive_closure_constraints (clobbers);
3757 make_constraint_to (uses->id, arg);
3758 make_constraint_to (clobbers->id, arg);
3759 returns_uses = true;
3762 make_escape_constraint (arg);
3765 /* If we added to the calls uses solution make sure we account for
3766 pointers to it to be returned. */
3769 rhsc.var = get_call_use_vi (stmt)->id;
3772 VEC_safe_push (ce_s, heap, *results, &rhsc);
3775 /* The static chain escapes as well. */
3776 if (gimple_call_chain (stmt))
3777 make_escape_constraint (gimple_call_chain (stmt));
3779 /* And if we applied NRV the address of the return slot escapes as well. */
3780 if (gimple_call_return_slot_opt_p (stmt)
3781 && gimple_call_lhs (stmt) != NULL_TREE
3782 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
3784 VEC(ce_s, heap) *tmpc = NULL;
3785 struct constraint_expr lhsc, *c;
3786 get_constraint_for_address_of (gimple_call_lhs (stmt), &tmpc);
3787 lhsc.var = escaped_id;
3790 FOR_EACH_VEC_ELT (ce_s, tmpc, i, c)
3791 process_constraint (new_constraint (lhsc, *c));
3792 VEC_free(ce_s, heap, tmpc);
3795 /* Regular functions return nonlocal memory. */
3796 rhsc.var = nonlocal_id;
3799 VEC_safe_push (ce_s, heap, *results, &rhsc);
3802 /* For non-IPA mode, generate constraints necessary for a call
3803 that returns a pointer and assigns it to LHS. This simply makes
3804 the LHS point to global and escaped variables. */
3807 handle_lhs_call (gimple stmt, tree lhs, int flags, VEC(ce_s, heap) *rhsc,
3810 VEC(ce_s, heap) *lhsc = NULL;
3812 get_constraint_for (lhs, &lhsc);
3813 /* If the store is to a global decl make sure to
3814 add proper escape constraints. */
3815 lhs = get_base_address (lhs);
3818 && is_global_var (lhs))
3820 struct constraint_expr tmpc;
3821 tmpc.var = escaped_id;
3824 VEC_safe_push (ce_s, heap, lhsc, &tmpc);
3827 /* If the call returns an argument unmodified override the rhs
3829 flags = gimple_call_return_flags (stmt);
3830 if (flags & ERF_RETURNS_ARG
3831 && (flags & ERF_RETURN_ARG_MASK) < gimple_call_num_args (stmt))
3835 arg = gimple_call_arg (stmt, flags & ERF_RETURN_ARG_MASK);
3836 get_constraint_for (arg, &rhsc);
3837 process_all_all_constraints (lhsc, rhsc);
3838 VEC_free (ce_s, heap, rhsc);
3840 else if (flags & ERF_NOALIAS)
3843 struct constraint_expr tmpc;
3845 vi = make_heapvar ("HEAP");
3846 /* We delay marking allocated storage global until we know if
3848 DECL_EXTERNAL (vi->decl) = 0;
3849 vi->is_global_var = 0;
3850 /* If this is not a real malloc call assume the memory was
3851 initialized and thus may point to global memory. All
3852 builtin functions with the malloc attribute behave in a sane way. */
3854 || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL)
3855 make_constraint_from (vi, nonlocal_id);
3858 tmpc.type = ADDRESSOF;
3859 VEC_safe_push (ce_s, heap, rhsc, &tmpc);
3862 process_all_all_constraints (lhsc, rhsc);
3864 VEC_free (ce_s, heap, lhsc);
3867 /* For non-IPA mode, generate constraints necessary for a call of a
3868 const function that returns a pointer in the statement STMT. */
3871 handle_const_call (gimple stmt, VEC(ce_s, heap) **results)
3873 struct constraint_expr rhsc;
3876 /* Treat nested const functions the same as pure functions as far
3877 as the static chain is concerned. */
3878 if (gimple_call_chain (stmt))
3880 varinfo_t uses = get_call_use_vi (stmt);
3881 make_transitive_closure_constraints (uses);
3882 make_constraint_to (uses->id, gimple_call_chain (stmt));
3883 rhsc.var = uses->id;
3886 VEC_safe_push (ce_s, heap, *results, &rhsc);
3889 /* May return arguments. */
3890 for (k = 0; k < gimple_call_num_args (stmt); ++k)
3892 tree arg = gimple_call_arg (stmt, k);
3893 VEC(ce_s, heap) *argc = NULL;
3895 struct constraint_expr *argp;
3896 get_constraint_for_rhs (arg, &argc);
3897 FOR_EACH_VEC_ELT (ce_s, argc, i, argp)
3898 VEC_safe_push (ce_s, heap, *results, argp);
3899 VEC_free(ce_s, heap, argc);
3902 /* May return addresses of globals. */
3903 rhsc.var = nonlocal_id;
3905 rhsc.type = ADDRESSOF;
3906 VEC_safe_push (ce_s, heap, *results, &rhsc);
3909 /* For non-IPA mode, generate constraints necessary for a call to a
3910 pure function in statement STMT. */
3913 handle_pure_call (gimple stmt, VEC(ce_s, heap) **results)
3915 struct constraint_expr rhsc;
3917 varinfo_t uses = NULL;
3919 /* Memory reached from pointer arguments is call-used. */
3920 for (i = 0; i < gimple_call_num_args (stmt); ++i)
3922 tree arg = gimple_call_arg (stmt, i);
3925 uses = get_call_use_vi (stmt);
3926 make_transitive_closure_constraints (uses);
3928 make_constraint_to (uses->id, arg);
3931 /* The static chain is used as well. */
3932 if (gimple_call_chain (stmt))
3936 uses = get_call_use_vi (stmt);
3937 make_transitive_closure_constraints (uses);
3939 make_constraint_to (uses->id, gimple_call_chain (stmt));
3942 /* Pure functions may return call-used and nonlocal memory. */
3945 rhsc.var = uses->id;
3948 VEC_safe_push (ce_s, heap, *results, &rhsc);
3950 rhsc.var = nonlocal_id;
3953 VEC_safe_push (ce_s, heap, *results, &rhsc);
3957 /* Return the varinfo for the callee of CALL. */
3960 get_fi_for_callee (gimple call)
3962 tree decl, fn = gimple_call_fn (call);
3964 if (fn && TREE_CODE (fn) == OBJ_TYPE_REF)
3965 fn = OBJ_TYPE_REF_EXPR (fn);
3967 /* If we can directly resolve the function being called, do so.
3968 Otherwise, it must be some sort of indirect expression that
3969 we should still be able to handle. */
3970 decl = gimple_call_addr_fndecl (fn);
3972 return get_vi_for_tree (decl);
3974 /* If the function is anything other than a SSA name pointer we have no
3975 clue and should be getting ANYFN (well, ANYTHING for now). */
3976 if (!fn || TREE_CODE (fn) != SSA_NAME)
3977 return get_varinfo (anything_id);
3979 if ((TREE_CODE (SSA_NAME_VAR (fn)) == PARM_DECL
3980 || TREE_CODE (SSA_NAME_VAR (fn)) == RESULT_DECL)
3981 && SSA_NAME_IS_DEFAULT_DEF (fn))
3982 fn = SSA_NAME_VAR (fn);
3984 return get_vi_for_tree (fn);
3987 /* Create constraints for the builtin call T. Return true if the call
3988 was handled, otherwise false. */
3991 find_func_aliases_for_builtin_call (gimple t)
3993 tree fndecl = gimple_call_fndecl (t);
3994 VEC(ce_s, heap) *lhsc = NULL;
3995 VEC(ce_s, heap) *rhsc = NULL;
3998 if (fndecl != NULL_TREE
3999 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
4000 /* ??? All builtins that are handled here need to be handled
4001 in the alias-oracle query functions explicitly! */
4002 switch (DECL_FUNCTION_CODE (fndecl))
4004 /* All the following functions return a pointer to the same object
4005 as their first argument points to. The functions do not add
4006 to the ESCAPED solution. The functions make the first argument
4007 pointed to memory point to what the second argument pointed to
4008 memory points to. */
4009 case BUILT_IN_STRCPY:
4010 case BUILT_IN_STRNCPY:
4011 case BUILT_IN_BCOPY:
4012 case BUILT_IN_MEMCPY:
4013 case BUILT_IN_MEMMOVE:
4014 case BUILT_IN_MEMPCPY:
4015 case BUILT_IN_STPCPY:
4016 case BUILT_IN_STPNCPY:
4017 case BUILT_IN_STRCAT:
4018 case BUILT_IN_STRNCAT:
4019 case BUILT_IN_STRCPY_CHK:
4020 case BUILT_IN_STRNCPY_CHK:
4021 case BUILT_IN_MEMCPY_CHK:
4022 case BUILT_IN_MEMMOVE_CHK:
4023 case BUILT_IN_MEMPCPY_CHK:
4024 case BUILT_IN_STPCPY_CHK:
4025 case BUILT_IN_STRCAT_CHK:
4026 case BUILT_IN_STRNCAT_CHK:
4028 tree res = gimple_call_lhs (t);
4029 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4030 == BUILT_IN_BCOPY ? 1 : 0));
4031 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (fndecl)
4032 == BUILT_IN_BCOPY ? 0 : 1));
4033 if (res != NULL_TREE)
4035 get_constraint_for (res, &lhsc);
4036 if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY
4037 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY
4038 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPNCPY
4039 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMPCPY_CHK
4040 || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STPCPY_CHK)
4041 get_constraint_for_ptr_offset (dest, NULL_TREE, &rhsc);
4043 get_constraint_for (dest, &rhsc);
4044 process_all_all_constraints (lhsc, rhsc);
4045 VEC_free (ce_s, heap, lhsc);
4046 VEC_free (ce_s, heap, rhsc);
4048 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4049 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4052 process_all_all_constraints (lhsc, rhsc);
4053 VEC_free (ce_s, heap, lhsc);
4054 VEC_free (ce_s, heap, rhsc);
4057 case BUILT_IN_MEMSET:
4058 case BUILT_IN_MEMSET_CHK:
4060 tree res = gimple_call_lhs (t);
4061 tree dest = gimple_call_arg (t, 0);
4064 struct constraint_expr ac;
4065 if (res != NULL_TREE)
4067 get_constraint_for (res, &lhsc);
4068 get_constraint_for (dest, &rhsc);
4069 process_all_all_constraints (lhsc, rhsc);
4070 VEC_free (ce_s, heap, lhsc);
4071 VEC_free (ce_s, heap, rhsc);
4073 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4075 if (flag_delete_null_pointer_checks
4076 && integer_zerop (gimple_call_arg (t, 1)))
4078 ac.type = ADDRESSOF;
4079 ac.var = nothing_id;
4084 ac.var = integer_id;
4087 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4088 process_constraint (new_constraint (*lhsp, ac));
4089 VEC_free (ce_s, heap, lhsc);
4092 case BUILT_IN_ASSUME_ALIGNED:
4094 tree res = gimple_call_lhs (t);
4095 tree dest = gimple_call_arg (t, 0);
4096 if (res != NULL_TREE)
4098 get_constraint_for (res, &lhsc);
4099 get_constraint_for (dest, &rhsc);
4100 process_all_all_constraints (lhsc, rhsc);
4101 VEC_free (ce_s, heap, lhsc);
4102 VEC_free (ce_s, heap, rhsc);
4106 /* All the following functions do not return pointers, do not
4107 modify the points-to sets of memory reachable from their
4108 arguments and do not add to the ESCAPED solution. */
4109 case BUILT_IN_SINCOS:
4110 case BUILT_IN_SINCOSF:
4111 case BUILT_IN_SINCOSL:
4112 case BUILT_IN_FREXP:
4113 case BUILT_IN_FREXPF:
4114 case BUILT_IN_FREXPL:
4115 case BUILT_IN_GAMMA_R:
4116 case BUILT_IN_GAMMAF_R:
4117 case BUILT_IN_GAMMAL_R:
4118 case BUILT_IN_LGAMMA_R:
4119 case BUILT_IN_LGAMMAF_R:
4120 case BUILT_IN_LGAMMAL_R:
4122 case BUILT_IN_MODFF:
4123 case BUILT_IN_MODFL:
4124 case BUILT_IN_REMQUO:
4125 case BUILT_IN_REMQUOF:
4126 case BUILT_IN_REMQUOL:
4129 case BUILT_IN_STRDUP:
4130 case BUILT_IN_STRNDUP:
4131 if (gimple_call_lhs (t))
4133 handle_lhs_call (t, gimple_call_lhs (t), gimple_call_flags (t),
4135 get_constraint_for_ptr_offset (gimple_call_lhs (t),
4137 get_constraint_for_ptr_offset (gimple_call_arg (t, 0),
4141 process_all_all_constraints (lhsc, rhsc);
4142 VEC_free (ce_s, heap, lhsc);
4143 VEC_free (ce_s, heap, rhsc);
4147 /* Trampolines are special - they set up passing the static
4149 case BUILT_IN_INIT_TRAMPOLINE:
4151 tree tramp = gimple_call_arg (t, 0);
4152 tree nfunc = gimple_call_arg (t, 1);
4153 tree frame = gimple_call_arg (t, 2);
4155 struct constraint_expr lhs, *rhsp;
4158 varinfo_t nfi = NULL;
4159 gcc_assert (TREE_CODE (nfunc) == ADDR_EXPR);
4160 nfi = lookup_vi_for_tree (TREE_OPERAND (nfunc, 0));
4163 lhs = get_function_part_constraint (nfi, fi_static_chain);
4164 get_constraint_for (frame, &rhsc);
4165 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4166 process_constraint (new_constraint (lhs, *rhsp));
4167 VEC_free (ce_s, heap, rhsc);
4169 /* Make the frame point to the function for
4170 the trampoline adjustment call. */
4171 get_constraint_for (tramp, &lhsc);
4173 get_constraint_for (nfunc, &rhsc);
4174 process_all_all_constraints (lhsc, rhsc);
4175 VEC_free (ce_s, heap, rhsc);
4176 VEC_free (ce_s, heap, lhsc);
4181 /* Else fallthru to generic handling which will let
4182 the frame escape. */
4185 case BUILT_IN_ADJUST_TRAMPOLINE:
4187 tree tramp = gimple_call_arg (t, 0);
4188 tree res = gimple_call_lhs (t);
4189 if (in_ipa_mode && res)
4191 get_constraint_for (res, &lhsc);
4192 get_constraint_for (tramp, &rhsc);
4194 process_all_all_constraints (lhsc, rhsc);
4195 VEC_free (ce_s, heap, rhsc);
4196 VEC_free (ce_s, heap, lhsc);
4200 /* Variadic argument handling needs to be handled in IPA
4202 case BUILT_IN_VA_START:
4204 tree valist = gimple_call_arg (t, 0);
4205 struct constraint_expr rhs, *lhsp;
4207 get_constraint_for (valist, &lhsc);
4209 /* The va_list gets access to pointers in variadic
4210 arguments. Which we know in the case of IPA analysis
4211 and otherwise are just all nonlocal variables. */
4214 fi = lookup_vi_for_tree (cfun->decl);
4215 rhs = get_function_part_constraint (fi, ~0);
4216 rhs.type = ADDRESSOF;
4220 rhs.var = nonlocal_id;
4221 rhs.type = ADDRESSOF;
4224 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4225 process_constraint (new_constraint (*lhsp, rhs));
4226 VEC_free (ce_s, heap, lhsc);
4227 /* va_list is clobbered. */
4228 make_constraint_to (get_call_clobber_vi (t)->id, valist);
4231 /* va_end doesn't have any effect that matters. */
4232 case BUILT_IN_VA_END:
4234 /* Alternate return. Simply give up for now. */
4235 case BUILT_IN_RETURN:
4239 || !(fi = get_vi_for_tree (cfun->decl)))
4240 make_constraint_from (get_varinfo (escaped_id), anything_id);
4241 else if (in_ipa_mode
4244 struct constraint_expr lhs, rhs;
4245 lhs = get_function_part_constraint (fi, fi_result);
4246 rhs.var = anything_id;
4249 process_constraint (new_constraint (lhs, rhs));
4253 /* printf-style functions may have hooks to set pointers to
4254 point to somewhere into the generated string. Leave them
4255 for a later excercise... */
4257 /* Fallthru to general call handling. */;
4263 /* Create constraints for the call T. */
4266 find_func_aliases_for_call (gimple t)
4268 tree fndecl = gimple_call_fndecl (t);
4269 VEC(ce_s, heap) *lhsc = NULL;
4270 VEC(ce_s, heap) *rhsc = NULL;
4273 if (fndecl != NULL_TREE
4274 && DECL_BUILT_IN (fndecl)
4275 && find_func_aliases_for_builtin_call (t))
4278 fi = get_fi_for_callee (t);
4280 || (fndecl && !fi->is_fn_info))
4282 VEC(ce_s, heap) *rhsc = NULL;
4283 int flags = gimple_call_flags (t);
4285 /* Const functions can return their arguments and addresses
4286 of global memory but not of escaped memory. */
4287 if (flags & (ECF_CONST|ECF_NOVOPS))
4289 if (gimple_call_lhs (t))
4290 handle_const_call (t, &rhsc);
4292 /* Pure functions can return addresses in and of memory
4293 reachable from their arguments, but they are not an escape
4294 point for reachable memory of their arguments. */
4295 else if (flags & (ECF_PURE|ECF_LOOPING_CONST_OR_PURE))
4296 handle_pure_call (t, &rhsc);
4298 handle_rhs_call (t, &rhsc);
4299 if (gimple_call_lhs (t))
4300 handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
4301 VEC_free (ce_s, heap, rhsc);
4308 /* Assign all the passed arguments to the appropriate incoming
4309 parameters of the function. */
4310 for (j = 0; j < gimple_call_num_args (t); j++)
4312 struct constraint_expr lhs ;
4313 struct constraint_expr *rhsp;
4314 tree arg = gimple_call_arg (t, j);
4316 get_constraint_for_rhs (arg, &rhsc);
4317 lhs = get_function_part_constraint (fi, fi_parm_base + j);
4318 while (VEC_length (ce_s, rhsc) != 0)
4320 rhsp = VEC_last (ce_s, rhsc);
4321 process_constraint (new_constraint (lhs, *rhsp));
4322 VEC_pop (ce_s, rhsc);
4326 /* If we are returning a value, assign it to the result. */
4327 lhsop = gimple_call_lhs (t);
4330 struct constraint_expr rhs;
4331 struct constraint_expr *lhsp;
4333 get_constraint_for (lhsop, &lhsc);
4334 rhs = get_function_part_constraint (fi, fi_result);
4336 && DECL_RESULT (fndecl)
4337 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4339 VEC(ce_s, heap) *tem = NULL;
4340 VEC_safe_push (ce_s, heap, tem, &rhs);
4342 rhs = *VEC_index (ce_s, tem, 0);
4343 VEC_free(ce_s, heap, tem);
4345 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4346 process_constraint (new_constraint (*lhsp, rhs));
4349 /* If we pass the result decl by reference, honor that. */
4352 && DECL_RESULT (fndecl)
4353 && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))
4355 struct constraint_expr lhs;
4356 struct constraint_expr *rhsp;
4358 get_constraint_for_address_of (lhsop, &rhsc);
4359 lhs = get_function_part_constraint (fi, fi_result);
4360 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4361 process_constraint (new_constraint (lhs, *rhsp));
4362 VEC_free (ce_s, heap, rhsc);
4365 /* If we use a static chain, pass it along. */
4366 if (gimple_call_chain (t))
4368 struct constraint_expr lhs;
4369 struct constraint_expr *rhsp;
4371 get_constraint_for (gimple_call_chain (t), &rhsc);
4372 lhs = get_function_part_constraint (fi, fi_static_chain);
4373 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4374 process_constraint (new_constraint (lhs, *rhsp));
4379 /* Walk statement T setting up aliasing constraints according to the
4380 references found in T. This function is the main part of the
4381 constraint builder. AI points to auxiliary alias information used
4382 when building alias sets and computing alias grouping heuristics. */
4385 find_func_aliases (gimple origt)
4388 VEC(ce_s, heap) *lhsc = NULL;
4389 VEC(ce_s, heap) *rhsc = NULL;
4390 struct constraint_expr *c;
4393 /* Now build constraints expressions. */
4394 if (gimple_code (t) == GIMPLE_PHI)
4399 /* For a phi node, assign all the arguments to
4401 get_constraint_for (gimple_phi_result (t), &lhsc);
4402 for (i = 0; i < gimple_phi_num_args (t); i++)
4404 tree strippedrhs = PHI_ARG_DEF (t, i);
4406 STRIP_NOPS (strippedrhs);
4407 get_constraint_for_rhs (gimple_phi_arg_def (t, i), &rhsc);
4409 FOR_EACH_VEC_ELT (ce_s, lhsc, j, c)
4411 struct constraint_expr *c2;
4412 while (VEC_length (ce_s, rhsc) > 0)
4414 c2 = VEC_last (ce_s, rhsc);
4415 process_constraint (new_constraint (*c, *c2));
4416 VEC_pop (ce_s, rhsc);
4421 /* In IPA mode, we need to generate constraints to pass call
4422 arguments through their calls. There are two cases,
4423 either a GIMPLE_CALL returning a value, or just a plain
4424 GIMPLE_CALL when we are not.
4426 In non-ipa mode, we need to generate constraints for each
4427 pointer passed by address. */
4428 else if (is_gimple_call (t))
4429 find_func_aliases_for_call (t);
4431 /* Otherwise, just a regular assignment statement. Only care about
4432 operations with pointer result, others are dealt with as escape
4433 points if they have pointer operands. */
4434 else if (is_gimple_assign (t))
4436 /* Otherwise, just a regular assignment statement. */
4437 tree lhsop = gimple_assign_lhs (t);
4438 tree rhsop = (gimple_num_ops (t) == 2) ? gimple_assign_rhs1 (t) : NULL;
4440 if (rhsop && AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
4441 do_structure_copy (lhsop, rhsop);
4444 enum tree_code code = gimple_assign_rhs_code (t);
4446 get_constraint_for (lhsop, &lhsc);
4448 if (code == POINTER_PLUS_EXPR)
4449 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4450 gimple_assign_rhs2 (t), &rhsc);
4451 else if (code == BIT_AND_EXPR
4452 && TREE_CODE (gimple_assign_rhs2 (t)) == INTEGER_CST)
4454 /* Aligning a pointer via a BIT_AND_EXPR is offsetting
4455 the pointer. Handle it by offsetting it by UNKNOWN. */
4456 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t),
4459 else if ((CONVERT_EXPR_CODE_P (code)
4460 && !(POINTER_TYPE_P (gimple_expr_type (t))
4461 && !POINTER_TYPE_P (TREE_TYPE (rhsop))))
4462 || gimple_assign_single_p (t))
4463 get_constraint_for_rhs (rhsop, &rhsc);
4464 else if (truth_value_p (code))
4465 /* Truth value results are not pointer (parts). Or at least
4466 very very unreasonable obfuscation of a part. */
4470 /* All other operations are merges. */
4471 VEC (ce_s, heap) *tmp = NULL;
4472 struct constraint_expr *rhsp;
4474 get_constraint_for_rhs (gimple_assign_rhs1 (t), &rhsc);
4475 for (i = 2; i < gimple_num_ops (t); ++i)
4477 get_constraint_for_rhs (gimple_op (t, i), &tmp);
4478 FOR_EACH_VEC_ELT (ce_s, tmp, j, rhsp)
4479 VEC_safe_push (ce_s, heap, rhsc, rhsp);
4480 VEC_truncate (ce_s, tmp, 0);
4482 VEC_free (ce_s, heap, tmp);
4484 process_all_all_constraints (lhsc, rhsc);
4486 /* If there is a store to a global variable the rhs escapes. */
4487 if ((lhsop = get_base_address (lhsop)) != NULL_TREE
4489 && is_global_var (lhsop)
4491 || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
4492 make_escape_constraint (rhsop);
4494 /* Handle escapes through return. */
4495 else if (gimple_code (t) == GIMPLE_RETURN
4496 && gimple_return_retval (t) != NULL_TREE)
4500 || !(fi = get_vi_for_tree (cfun->decl)))
4501 make_escape_constraint (gimple_return_retval (t));
4502 else if (in_ipa_mode
4505 struct constraint_expr lhs ;
4506 struct constraint_expr *rhsp;
4509 lhs = get_function_part_constraint (fi, fi_result);
4510 get_constraint_for_rhs (gimple_return_retval (t), &rhsc);
4511 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4512 process_constraint (new_constraint (lhs, *rhsp));
4515 /* Handle asms conservatively by adding escape constraints to everything. */
4516 else if (gimple_code (t) == GIMPLE_ASM)
4518 unsigned i, noutputs;
4519 const char **oconstraints;
4520 const char *constraint;
4521 bool allows_mem, allows_reg, is_inout;
4523 noutputs = gimple_asm_noutputs (t);
4524 oconstraints = XALLOCAVEC (const char *, noutputs);
4526 for (i = 0; i < noutputs; ++i)
4528 tree link = gimple_asm_output_op (t, i);
4529 tree op = TREE_VALUE (link);
4531 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4532 oconstraints[i] = constraint;
4533 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
4534 &allows_reg, &is_inout);
4536 /* A memory constraint makes the address of the operand escape. */
4537 if (!allows_reg && allows_mem)
4538 make_escape_constraint (build_fold_addr_expr (op));
4540 /* The asm may read global memory, so outputs may point to
4541 any global memory. */
4544 VEC(ce_s, heap) *lhsc = NULL;
4545 struct constraint_expr rhsc, *lhsp;
4547 get_constraint_for (op, &lhsc);
4548 rhsc.var = nonlocal_id;
4551 FOR_EACH_VEC_ELT (ce_s, lhsc, j, lhsp)
4552 process_constraint (new_constraint (*lhsp, rhsc));
4553 VEC_free (ce_s, heap, lhsc);
4556 for (i = 0; i < gimple_asm_ninputs (t); ++i)
4558 tree link = gimple_asm_input_op (t, i);
4559 tree op = TREE_VALUE (link);
4561 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
4563 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
4564 &allows_mem, &allows_reg);
4566 /* A memory constraint makes the address of the operand escape. */
4567 if (!allows_reg && allows_mem)
4568 make_escape_constraint (build_fold_addr_expr (op));
4569 /* Strictly we'd only need the constraint to ESCAPED if
4570 the asm clobbers memory, otherwise using something
4571 along the lines of per-call clobbers/uses would be enough. */
4573 make_escape_constraint (op);
4577 VEC_free (ce_s, heap, rhsc);
4578 VEC_free (ce_s, heap, lhsc);
4582 /* Create a constraint adding to the clobber set of FI the memory
4583 pointed to by PTR. */
4586 process_ipa_clobber (varinfo_t fi, tree ptr)
4588 VEC(ce_s, heap) *ptrc = NULL;
4589 struct constraint_expr *c, lhs;
4591 get_constraint_for_rhs (ptr, &ptrc);
4592 lhs = get_function_part_constraint (fi, fi_clobbers);
4593 FOR_EACH_VEC_ELT (ce_s, ptrc, i, c)
4594 process_constraint (new_constraint (lhs, *c));
4595 VEC_free (ce_s, heap, ptrc);
4598 /* Walk statement T setting up clobber and use constraints according to the
4599 references found in T. This function is a main part of the
4600 IPA constraint builder. */
4603 find_func_clobbers (gimple origt)
4606 VEC(ce_s, heap) *lhsc = NULL;
4607 VEC(ce_s, heap) *rhsc = NULL;
4610 /* Add constraints for clobbered/used in IPA mode.
4611 We are not interested in what automatic variables are clobbered
4612 or used as we only use the information in the caller to which
4613 they do not escape. */
4614 gcc_assert (in_ipa_mode);
4616 /* If the stmt refers to memory in any way it better had a VUSE. */
4617 if (gimple_vuse (t) == NULL_TREE)
4620 /* We'd better have function information for the current function. */
4621 fi = lookup_vi_for_tree (cfun->decl);
4622 gcc_assert (fi != NULL);
4624 /* Account for stores in assignments and calls. */
4625 if (gimple_vdef (t) != NULL_TREE
4626 && gimple_has_lhs (t))
4628 tree lhs = gimple_get_lhs (t);
4630 while (handled_component_p (tem))
4631 tem = TREE_OPERAND (tem, 0);
4633 && !auto_var_in_fn_p (tem, cfun->decl))
4634 || INDIRECT_REF_P (tem)
4635 || (TREE_CODE (tem) == MEM_REF
4636 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4638 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4640 struct constraint_expr lhsc, *rhsp;
4642 lhsc = get_function_part_constraint (fi, fi_clobbers);
4643 get_constraint_for_address_of (lhs, &rhsc);
4644 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4645 process_constraint (new_constraint (lhsc, *rhsp));
4646 VEC_free (ce_s, heap, rhsc);
4650 /* Account for uses in assigments and returns. */
4651 if (gimple_assign_single_p (t)
4652 || (gimple_code (t) == GIMPLE_RETURN
4653 && gimple_return_retval (t) != NULL_TREE))
4655 tree rhs = (gimple_assign_single_p (t)
4656 ? gimple_assign_rhs1 (t) : gimple_return_retval (t));
4658 while (handled_component_p (tem))
4659 tem = TREE_OPERAND (tem, 0);
4661 && !auto_var_in_fn_p (tem, cfun->decl))
4662 || INDIRECT_REF_P (tem)
4663 || (TREE_CODE (tem) == MEM_REF
4664 && !(TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR
4666 (TREE_OPERAND (TREE_OPERAND (tem, 0), 0), cfun->decl))))
4668 struct constraint_expr lhs, *rhsp;
4670 lhs = get_function_part_constraint (fi, fi_uses);
4671 get_constraint_for_address_of (rhs, &rhsc);
4672 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4673 process_constraint (new_constraint (lhs, *rhsp));
4674 VEC_free (ce_s, heap, rhsc);
4678 if (is_gimple_call (t))
4680 varinfo_t cfi = NULL;
4681 tree decl = gimple_call_fndecl (t);
4682 struct constraint_expr lhs, rhs;
4685 /* For builtins we do not have separate function info. For those
4686 we do not generate escapes for we have to generate clobbers/uses. */
4688 && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
4689 switch (DECL_FUNCTION_CODE (decl))
4691 /* The following functions use and clobber memory pointed to
4692 by their arguments. */
4693 case BUILT_IN_STRCPY:
4694 case BUILT_IN_STRNCPY:
4695 case BUILT_IN_BCOPY:
4696 case BUILT_IN_MEMCPY:
4697 case BUILT_IN_MEMMOVE:
4698 case BUILT_IN_MEMPCPY:
4699 case BUILT_IN_STPCPY:
4700 case BUILT_IN_STPNCPY:
4701 case BUILT_IN_STRCAT:
4702 case BUILT_IN_STRNCAT:
4703 case BUILT_IN_STRCPY_CHK:
4704 case BUILT_IN_STRNCPY_CHK:
4705 case BUILT_IN_MEMCPY_CHK:
4706 case BUILT_IN_MEMMOVE_CHK:
4707 case BUILT_IN_MEMPCPY_CHK:
4708 case BUILT_IN_STPCPY_CHK:
4709 case BUILT_IN_STRCAT_CHK:
4710 case BUILT_IN_STRNCAT_CHK:
4712 tree dest = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4713 == BUILT_IN_BCOPY ? 1 : 0));
4714 tree src = gimple_call_arg (t, (DECL_FUNCTION_CODE (decl)
4715 == BUILT_IN_BCOPY ? 0 : 1));
4717 struct constraint_expr *rhsp, *lhsp;
4718 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4719 lhs = get_function_part_constraint (fi, fi_clobbers);
4720 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4721 process_constraint (new_constraint (lhs, *lhsp));
4722 VEC_free (ce_s, heap, lhsc);
4723 get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
4724 lhs = get_function_part_constraint (fi, fi_uses);
4725 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
4726 process_constraint (new_constraint (lhs, *rhsp));
4727 VEC_free (ce_s, heap, rhsc);
4730 /* The following function clobbers memory pointed to by
4732 case BUILT_IN_MEMSET:
4733 case BUILT_IN_MEMSET_CHK:
4735 tree dest = gimple_call_arg (t, 0);
4738 get_constraint_for_ptr_offset (dest, NULL_TREE, &lhsc);
4739 lhs = get_function_part_constraint (fi, fi_clobbers);
4740 FOR_EACH_VEC_ELT (ce_s, lhsc, i, lhsp)
4741 process_constraint (new_constraint (lhs, *lhsp));
4742 VEC_free (ce_s, heap, lhsc);
4745 /* The following functions clobber their second and third
4747 case BUILT_IN_SINCOS:
4748 case BUILT_IN_SINCOSF:
4749 case BUILT_IN_SINCOSL:
4751 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4752 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4755 /* The following functions clobber their second argument. */
4756 case BUILT_IN_FREXP:
4757 case BUILT_IN_FREXPF:
4758 case BUILT_IN_FREXPL:
4759 case BUILT_IN_LGAMMA_R:
4760 case BUILT_IN_LGAMMAF_R:
4761 case BUILT_IN_LGAMMAL_R:
4762 case BUILT_IN_GAMMA_R:
4763 case BUILT_IN_GAMMAF_R:
4764 case BUILT_IN_GAMMAL_R:
4766 case BUILT_IN_MODFF:
4767 case BUILT_IN_MODFL:
4769 process_ipa_clobber (fi, gimple_call_arg (t, 1));
4772 /* The following functions clobber their third argument. */
4773 case BUILT_IN_REMQUO:
4774 case BUILT_IN_REMQUOF:
4775 case BUILT_IN_REMQUOL:
4777 process_ipa_clobber (fi, gimple_call_arg (t, 2));
4780 /* The following functions neither read nor clobber memory. */
4781 case BUILT_IN_ASSUME_ALIGNED:
4784 /* Trampolines are of no interest to us. */
4785 case BUILT_IN_INIT_TRAMPOLINE:
4786 case BUILT_IN_ADJUST_TRAMPOLINE:
4788 case BUILT_IN_VA_START:
4789 case BUILT_IN_VA_END:
4791 /* printf-style functions may have hooks to set pointers to
4792 point to somewhere into the generated string. Leave them
4793 for a later excercise... */
4795 /* Fallthru to general call handling. */;
4798 /* Parameters passed by value are used. */
4799 lhs = get_function_part_constraint (fi, fi_uses);
4800 for (i = 0; i < gimple_call_num_args (t); i++)
4802 struct constraint_expr *rhsp;
4803 tree arg = gimple_call_arg (t, i);
4805 if (TREE_CODE (arg) == SSA_NAME
4806 || is_gimple_min_invariant (arg))
4809 get_constraint_for_address_of (arg, &rhsc);
4810 FOR_EACH_VEC_ELT (ce_s, rhsc, j, rhsp)
4811 process_constraint (new_constraint (lhs, *rhsp));
4812 VEC_free (ce_s, heap, rhsc);
4815 /* Build constraints for propagating clobbers/uses along the
4817 cfi = get_fi_for_callee (t);
4818 if (cfi->id == anything_id)
4820 if (gimple_vdef (t))
4821 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4823 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4828 /* For callees without function info (that's external functions),
4829 ESCAPED is clobbered and used. */
4830 if (gimple_call_fndecl (t)
4831 && !cfi->is_fn_info)
4835 if (gimple_vdef (t))
4836 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4838 make_copy_constraint (first_vi_for_offset (fi, fi_uses), escaped_id);
4840 /* Also honor the call statement use/clobber info. */
4841 if ((vi = lookup_call_clobber_vi (t)) != NULL)
4842 make_copy_constraint (first_vi_for_offset (fi, fi_clobbers),
4844 if ((vi = lookup_call_use_vi (t)) != NULL)
4845 make_copy_constraint (first_vi_for_offset (fi, fi_uses),
4850 /* Otherwise the caller clobbers and uses what the callee does.
4851 ??? This should use a new complex constraint that filters
4852 local variables of the callee. */
4853 if (gimple_vdef (t))
4855 lhs = get_function_part_constraint (fi, fi_clobbers);
4856 rhs = get_function_part_constraint (cfi, fi_clobbers);
4857 process_constraint (new_constraint (lhs, rhs));
4859 lhs = get_function_part_constraint (fi, fi_uses);
4860 rhs = get_function_part_constraint (cfi, fi_uses);
4861 process_constraint (new_constraint (lhs, rhs));
4863 else if (gimple_code (t) == GIMPLE_ASM)
4865 /* ??? Ick. We can do better. */
4866 if (gimple_vdef (t))
4867 make_constraint_from (first_vi_for_offset (fi, fi_clobbers),
4869 make_constraint_from (first_vi_for_offset (fi, fi_uses),
4873 VEC_free (ce_s, heap, rhsc);
4877 /* Find the first varinfo in the same variable as START that overlaps with
4878 OFFSET. Return NULL if we can't find one. */
4881 first_vi_for_offset (varinfo_t start, unsigned HOST_WIDE_INT offset)
4883 /* If the offset is outside of the variable, bail out. */
4884 if (offset >= start->fullsize)
4887 /* If we cannot reach offset from start, lookup the first field
4888 and start from there. */
4889 if (start->offset > offset)
4890 start = lookup_vi_for_tree (start->decl);
4894 /* We may not find a variable in the field list with the actual
4895 offset when when we have glommed a structure to a variable.
4896 In that case, however, offset should still be within the size
4898 if (offset >= start->offset
4899 && (offset - start->offset) < start->size)
4908 /* Find the first varinfo in the same variable as START that overlaps with
4909 OFFSET. If there is no such varinfo the varinfo directly preceding
4910 OFFSET is returned. */
4913 first_or_preceding_vi_for_offset (varinfo_t start,
4914 unsigned HOST_WIDE_INT offset)
4916 /* If we cannot reach offset from start, lookup the first field
4917 and start from there. */
4918 if (start->offset > offset)
4919 start = lookup_vi_for_tree (start->decl);
4921 /* We may not find a variable in the field list with the actual
4922 offset when when we have glommed a structure to a variable.
4923 In that case, however, offset should still be within the size
4925 If we got beyond the offset we look for return the field
4926 directly preceding offset which may be the last field. */
4928 && offset >= start->offset
4929 && !((offset - start->offset) < start->size))
4930 start = start->next;
4936 /* This structure is used during pushing fields onto the fieldstack
4937 to track the offset of the field, since bitpos_of_field gives it
4938 relative to its immediate containing type, and we want it relative
4939 to the ultimate containing object. */
4943 /* Offset from the base of the base containing object to this field. */
4944 HOST_WIDE_INT offset;
4946 /* Size, in bits, of the field. */
4947 unsigned HOST_WIDE_INT size;
4949 unsigned has_unknown_size : 1;
4951 unsigned must_have_pointers : 1;
4953 unsigned may_have_pointers : 1;
4955 unsigned only_restrict_pointers : 1;
4957 typedef struct fieldoff fieldoff_s;
4959 DEF_VEC_O(fieldoff_s);
4960 DEF_VEC_ALLOC_O(fieldoff_s,heap);
4962 /* qsort comparison function for two fieldoff's PA and PB */
4965 fieldoff_compare (const void *pa, const void *pb)
4967 const fieldoff_s *foa = (const fieldoff_s *)pa;
4968 const fieldoff_s *fob = (const fieldoff_s *)pb;
4969 unsigned HOST_WIDE_INT foasize, fobsize;
4971 if (foa->offset < fob->offset)
4973 else if (foa->offset > fob->offset)
4976 foasize = foa->size;
4977 fobsize = fob->size;
4978 if (foasize < fobsize)
4980 else if (foasize > fobsize)
4985 /* Sort a fieldstack according to the field offset and sizes. */
4987 sort_fieldstack (VEC(fieldoff_s,heap) *fieldstack)
4989 VEC_qsort (fieldoff_s, fieldstack, fieldoff_compare);
4992 /* Return true if V is a tree that we can have subvars for.
4993 Normally, this is any aggregate type. Also complex
4994 types which are not gimple registers can have subvars. */
4997 var_can_have_subvars (const_tree v)
4999 /* Volatile variables should never have subvars. */
5000 if (TREE_THIS_VOLATILE (v))
5003 /* Non decls or memory tags can never have subvars. */
5007 /* Aggregates without overlapping fields can have subvars. */
5008 if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE)
5014 /* Return true if T is a type that does contain pointers. */
5017 type_must_have_pointers (tree type)
5019 if (POINTER_TYPE_P (type))
5022 if (TREE_CODE (type) == ARRAY_TYPE)
5023 return type_must_have_pointers (TREE_TYPE (type));
5025 /* A function or method can have pointers as arguments, so track
5026 those separately. */
5027 if (TREE_CODE (type) == FUNCTION_TYPE
5028 || TREE_CODE (type) == METHOD_TYPE)
5035 field_must_have_pointers (tree t)
5037 return type_must_have_pointers (TREE_TYPE (t));
5040 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
5041 the fields of TYPE onto fieldstack, recording their offsets along
5044 OFFSET is used to keep track of the offset in this entire
5045 structure, rather than just the immediately containing structure.
5046 Returns false if the caller is supposed to handle the field we
5050 push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
5051 HOST_WIDE_INT offset)
5054 bool empty_p = true;
5056 if (TREE_CODE (type) != RECORD_TYPE)
5059 /* If the vector of fields is growing too big, bail out early.
5060 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
5062 if (VEC_length (fieldoff_s, *fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5065 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
5066 if (TREE_CODE (field) == FIELD_DECL)
5069 HOST_WIDE_INT foff = bitpos_of_field (field);
5071 if (!var_can_have_subvars (field)
5072 || TREE_CODE (TREE_TYPE (field)) == QUAL_UNION_TYPE
5073 || TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
5075 else if (!push_fields_onto_fieldstack
5076 (TREE_TYPE (field), fieldstack, offset + foff)
5077 && (DECL_SIZE (field)
5078 && !integer_zerop (DECL_SIZE (field))))
5079 /* Empty structures may have actual size, like in C++. So
5080 see if we didn't push any subfields and the size is
5081 nonzero, push the field onto the stack. */
5086 fieldoff_s *pair = NULL;
5087 bool has_unknown_size = false;
5088 bool must_have_pointers_p;
5090 if (!VEC_empty (fieldoff_s, *fieldstack))
5091 pair = VEC_last (fieldoff_s, *fieldstack);
5093 /* If there isn't anything at offset zero, create sth. */
5095 && offset + foff != 0)
5097 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5099 pair->size = offset + foff;
5100 pair->has_unknown_size = false;
5101 pair->must_have_pointers = false;
5102 pair->may_have_pointers = false;
5103 pair->only_restrict_pointers = false;
5106 if (!DECL_SIZE (field)
5107 || !host_integerp (DECL_SIZE (field), 1))
5108 has_unknown_size = true;
5110 /* If adjacent fields do not contain pointers merge them. */
5111 must_have_pointers_p = field_must_have_pointers (field);
5113 && !has_unknown_size
5114 && !must_have_pointers_p
5115 && !pair->must_have_pointers
5116 && !pair->has_unknown_size
5117 && pair->offset + (HOST_WIDE_INT)pair->size == offset + foff)
5119 pair->size += TREE_INT_CST_LOW (DECL_SIZE (field));
5123 pair = VEC_safe_push (fieldoff_s, heap, *fieldstack, NULL);
5124 pair->offset = offset + foff;
5125 pair->has_unknown_size = has_unknown_size;
5126 if (!has_unknown_size)
5127 pair->size = TREE_INT_CST_LOW (DECL_SIZE (field));
5130 pair->must_have_pointers = must_have_pointers_p;
5131 pair->may_have_pointers = true;
5132 pair->only_restrict_pointers
5133 = (!has_unknown_size
5134 && POINTER_TYPE_P (TREE_TYPE (field))
5135 && TYPE_RESTRICT (TREE_TYPE (field)));
5145 /* Count the number of arguments DECL has, and set IS_VARARGS to true
5146 if it is a varargs function. */
5149 count_num_arguments (tree decl, bool *is_varargs)
5151 unsigned int num = 0;
5154 /* Capture named arguments for K&R functions. They do not
5155 have a prototype and thus no TYPE_ARG_TYPES. */
5156 for (t = DECL_ARGUMENTS (decl); t; t = DECL_CHAIN (t))
5159 /* Check if the function has variadic arguments. */
5160 for (t = TYPE_ARG_TYPES (TREE_TYPE (decl)); t; t = TREE_CHAIN (t))
5161 if (TREE_VALUE (t) == void_type_node)
5169 /* Creation function node for DECL, using NAME, and return the index
5170 of the variable we've created for the function. */
5173 create_function_info_for (tree decl, const char *name)
5175 struct function *fn = DECL_STRUCT_FUNCTION (decl);
5176 varinfo_t vi, prev_vi;
5179 bool is_varargs = false;
5180 unsigned int num_args = count_num_arguments (decl, &is_varargs);
5182 /* Create the variable info. */
5184 vi = new_var_info (decl, name);
5187 vi->fullsize = fi_parm_base + num_args;
5189 vi->may_have_pointers = false;
5192 insert_vi_for_tree (vi->decl, vi);
5196 /* Create a variable for things the function clobbers and one for
5197 things the function uses. */
5199 varinfo_t clobbervi, usevi;
5200 const char *newname;
5203 asprintf (&tempname, "%s.clobber", name);
5204 newname = ggc_strdup (tempname);
5207 clobbervi = new_var_info (NULL, newname);
5208 clobbervi->offset = fi_clobbers;
5209 clobbervi->size = 1;
5210 clobbervi->fullsize = vi->fullsize;
5211 clobbervi->is_full_var = true;
5212 clobbervi->is_global_var = false;
5213 gcc_assert (prev_vi->offset < clobbervi->offset);
5214 prev_vi->next = clobbervi;
5215 prev_vi = clobbervi;
5217 asprintf (&tempname, "%s.use", name);
5218 newname = ggc_strdup (tempname);
5221 usevi = new_var_info (NULL, newname);
5222 usevi->offset = fi_uses;
5224 usevi->fullsize = vi->fullsize;
5225 usevi->is_full_var = true;
5226 usevi->is_global_var = false;
5227 gcc_assert (prev_vi->offset < usevi->offset);
5228 prev_vi->next = usevi;
5232 /* And one for the static chain. */
5233 if (fn->static_chain_decl != NULL_TREE)
5236 const char *newname;
5239 asprintf (&tempname, "%s.chain", name);
5240 newname = ggc_strdup (tempname);
5243 chainvi = new_var_info (fn->static_chain_decl, newname);
5244 chainvi->offset = fi_static_chain;
5246 chainvi->fullsize = vi->fullsize;
5247 chainvi->is_full_var = true;
5248 chainvi->is_global_var = false;
5249 gcc_assert (prev_vi->offset < chainvi->offset);
5250 prev_vi->next = chainvi;
5252 insert_vi_for_tree (fn->static_chain_decl, chainvi);
5255 /* Create a variable for the return var. */
5256 if (DECL_RESULT (decl) != NULL
5257 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
5260 const char *newname;
5262 tree resultdecl = decl;
5264 if (DECL_RESULT (decl))
5265 resultdecl = DECL_RESULT (decl);
5267 asprintf (&tempname, "%s.result", name);
5268 newname = ggc_strdup (tempname);
5271 resultvi = new_var_info (resultdecl, newname);
5272 resultvi->offset = fi_result;
5274 resultvi->fullsize = vi->fullsize;
5275 resultvi->is_full_var = true;
5276 if (DECL_RESULT (decl))
5277 resultvi->may_have_pointers = true;
5278 gcc_assert (prev_vi->offset < resultvi->offset);
5279 prev_vi->next = resultvi;
5281 if (DECL_RESULT (decl))
5282 insert_vi_for_tree (DECL_RESULT (decl), resultvi);
5285 /* Set up variables for each argument. */
5286 arg = DECL_ARGUMENTS (decl);
5287 for (i = 0; i < num_args; i++)
5290 const char *newname;
5292 tree argdecl = decl;
5297 asprintf (&tempname, "%s.arg%d", name, i);
5298 newname = ggc_strdup (tempname);
5301 argvi = new_var_info (argdecl, newname);
5302 argvi->offset = fi_parm_base + i;
5304 argvi->is_full_var = true;
5305 argvi->fullsize = vi->fullsize;
5307 argvi->may_have_pointers = true;
5308 gcc_assert (prev_vi->offset < argvi->offset);
5309 prev_vi->next = argvi;
5313 insert_vi_for_tree (arg, argvi);
5314 arg = DECL_CHAIN (arg);
5318 /* Add one representative for all further args. */
5322 const char *newname;
5326 asprintf (&tempname, "%s.varargs", name);
5327 newname = ggc_strdup (tempname);
5330 /* We need sth that can be pointed to for va_start. */
5331 decl = build_fake_var_decl (ptr_type_node);
5333 argvi = new_var_info (decl, newname);
5334 argvi->offset = fi_parm_base + num_args;
5336 argvi->is_full_var = true;
5337 argvi->is_heap_var = true;
5338 argvi->fullsize = vi->fullsize;
5339 gcc_assert (prev_vi->offset < argvi->offset);
5340 prev_vi->next = argvi;
5348 /* Return true if FIELDSTACK contains fields that overlap.
5349 FIELDSTACK is assumed to be sorted by offset. */
5352 check_for_overlaps (VEC (fieldoff_s,heap) *fieldstack)
5354 fieldoff_s *fo = NULL;
5356 HOST_WIDE_INT lastoffset = -1;
5358 FOR_EACH_VEC_ELT (fieldoff_s, fieldstack, i, fo)
5360 if (fo->offset == lastoffset)
5362 lastoffset = fo->offset;
5367 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
5368 This will also create any varinfo structures necessary for fields
5372 create_variable_info_for_1 (tree decl, const char *name)
5374 varinfo_t vi, newvi;
5375 tree decl_type = TREE_TYPE (decl);
5376 tree declsize = DECL_P (decl) ? DECL_SIZE (decl) : TYPE_SIZE (decl_type);
5377 VEC (fieldoff_s,heap) *fieldstack = NULL;
5382 || !host_integerp (declsize, 1))
5384 vi = new_var_info (decl, name);
5388 vi->is_unknown_size_var = true;
5389 vi->is_full_var = true;
5390 vi->may_have_pointers = true;
5394 /* Collect field information. */
5395 if (use_field_sensitive
5396 && var_can_have_subvars (decl)
5397 /* ??? Force us to not use subfields for global initializers
5398 in IPA mode. Else we'd have to parse arbitrary initializers. */
5400 && is_global_var (decl)
5401 && DECL_INITIAL (decl)))
5403 fieldoff_s *fo = NULL;
5404 bool notokay = false;
5407 push_fields_onto_fieldstack (decl_type, &fieldstack, 0);
5409 for (i = 0; !notokay && VEC_iterate (fieldoff_s, fieldstack, i, fo); i++)
5410 if (fo->has_unknown_size
5417 /* We can't sort them if we have a field with a variable sized type,
5418 which will make notokay = true. In that case, we are going to return
5419 without creating varinfos for the fields anyway, so sorting them is a
5423 sort_fieldstack (fieldstack);
5424 /* Due to some C++ FE issues, like PR 22488, we might end up
5425 what appear to be overlapping fields even though they,
5426 in reality, do not overlap. Until the C++ FE is fixed,
5427 we will simply disable field-sensitivity for these cases. */
5428 notokay = check_for_overlaps (fieldstack);
5432 VEC_free (fieldoff_s, heap, fieldstack);
5435 /* If we didn't end up collecting sub-variables create a full
5436 variable for the decl. */
5437 if (VEC_length (fieldoff_s, fieldstack) <= 1
5438 || VEC_length (fieldoff_s, fieldstack) > MAX_FIELDS_FOR_FIELD_SENSITIVE)
5440 vi = new_var_info (decl, name);
5442 vi->may_have_pointers = true;
5443 vi->fullsize = TREE_INT_CST_LOW (declsize);
5444 vi->size = vi->fullsize;
5445 vi->is_full_var = true;
5446 VEC_free (fieldoff_s, heap, fieldstack);
5450 vi = new_var_info (decl, name);
5451 vi->fullsize = TREE_INT_CST_LOW (declsize);
5452 for (i = 0, newvi = vi;
5453 VEC_iterate (fieldoff_s, fieldstack, i, fo);
5454 ++i, newvi = newvi->next)
5456 const char *newname = "NULL";
5461 asprintf (&tempname, "%s." HOST_WIDE_INT_PRINT_DEC
5462 "+" HOST_WIDE_INT_PRINT_DEC, name, fo->offset, fo->size);
5463 newname = ggc_strdup (tempname);
5466 newvi->name = newname;
5467 newvi->offset = fo->offset;
5468 newvi->size = fo->size;
5469 newvi->fullsize = vi->fullsize;
5470 newvi->may_have_pointers = fo->may_have_pointers;
5471 newvi->only_restrict_pointers = fo->only_restrict_pointers;
5472 if (i + 1 < VEC_length (fieldoff_s, fieldstack))
5473 newvi->next = new_var_info (decl, name);
5476 VEC_free (fieldoff_s, heap, fieldstack);
5482 create_variable_info_for (tree decl, const char *name)
5484 varinfo_t vi = create_variable_info_for_1 (decl, name);
5485 unsigned int id = vi->id;
5487 insert_vi_for_tree (decl, vi);
5489 if (TREE_CODE (decl) != VAR_DECL)
5492 /* Create initial constraints for globals. */
5493 for (; vi; vi = vi->next)
5495 if (!vi->may_have_pointers
5496 || !vi->is_global_var)
5499 /* Mark global restrict qualified pointers. */
5500 if ((POINTER_TYPE_P (TREE_TYPE (decl))
5501 && TYPE_RESTRICT (TREE_TYPE (decl)))
5502 || vi->only_restrict_pointers)
5504 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
5508 /* In non-IPA mode the initializer from nonlocal is all we need. */
5510 || DECL_HARD_REGISTER (decl))
5511 make_copy_constraint (vi, nonlocal_id);
5513 /* In IPA mode parse the initializer and generate proper constraints
5517 struct varpool_node *vnode = varpool_get_node (decl);
5519 /* For escaped variables initialize them from nonlocal. */
5520 if (!varpool_all_refs_explicit_p (vnode))
5521 make_copy_constraint (vi, nonlocal_id);
5523 /* If this is a global variable with an initializer and we are in
5524 IPA mode generate constraints for it. */
5525 if (DECL_INITIAL (decl))
5527 VEC (ce_s, heap) *rhsc = NULL;
5528 struct constraint_expr lhs, *rhsp;
5530 get_constraint_for_rhs (DECL_INITIAL (decl), &rhsc);
5534 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5535 process_constraint (new_constraint (lhs, *rhsp));
5536 /* If this is a variable that escapes from the unit
5537 the initializer escapes as well. */
5538 if (!varpool_all_refs_explicit_p (vnode))
5540 lhs.var = escaped_id;
5543 FOR_EACH_VEC_ELT (ce_s, rhsc, i, rhsp)
5544 process_constraint (new_constraint (lhs, *rhsp));
5546 VEC_free (ce_s, heap, rhsc);
5554 /* Print out the points-to solution for VAR to FILE. */
5557 dump_solution_for_var (FILE *file, unsigned int var)
5559 varinfo_t vi = get_varinfo (var);
5563 /* Dump the solution for unified vars anyway, this avoids difficulties
5564 in scanning dumps in the testsuite. */
5565 fprintf (file, "%s = { ", vi->name);
5566 vi = get_varinfo (find (var));
5567 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5568 fprintf (file, "%s ", get_varinfo (i)->name);
5569 fprintf (file, "}");
5571 /* But note when the variable was unified. */
5573 fprintf (file, " same as %s", vi->name);
5575 fprintf (file, "\n");
5578 /* Print the points-to solution for VAR to stdout. */
5581 debug_solution_for_var (unsigned int var)
5583 dump_solution_for_var (stdout, var);
5586 /* Create varinfo structures for all of the variables in the
5587 function for intraprocedural mode. */
5590 intra_create_variable_infos (void)
5594 /* For each incoming pointer argument arg, create the constraint ARG
5595 = NONLOCAL or a dummy variable if it is a restrict qualified
5596 passed-by-reference argument. */
5597 for (t = DECL_ARGUMENTS (current_function_decl); t; t = DECL_CHAIN (t))
5599 varinfo_t p = get_vi_for_tree (t);
5601 /* For restrict qualified pointers to objects passed by
5602 reference build a real representative for the pointed-to object.
5603 Treat restrict qualified references the same. */
5604 if (TYPE_RESTRICT (TREE_TYPE (t))
5605 && ((DECL_BY_REFERENCE (t) && POINTER_TYPE_P (TREE_TYPE (t)))
5606 || TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE))
5608 struct constraint_expr lhsc, rhsc;
5610 tree heapvar = build_fake_var_decl (TREE_TYPE (TREE_TYPE (t)));
5611 DECL_EXTERNAL (heapvar) = 1;
5612 vi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS");
5613 insert_vi_for_tree (heapvar, vi);
5618 rhsc.type = ADDRESSOF;
5620 process_constraint (new_constraint (lhsc, rhsc));
5621 for (; vi; vi = vi->next)
5622 if (vi->may_have_pointers)
5624 if (vi->only_restrict_pointers)
5625 make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
5627 make_copy_constraint (vi, nonlocal_id);
5632 if (POINTER_TYPE_P (TREE_TYPE (t))
5633 && TYPE_RESTRICT (TREE_TYPE (t)))
5634 make_constraint_from_global_restrict (p, "PARM_RESTRICT");
5637 for (; p; p = p->next)
5639 if (p->only_restrict_pointers)
5640 make_constraint_from_global_restrict (p, "PARM_RESTRICT");
5641 else if (p->may_have_pointers)
5642 make_constraint_from (p, nonlocal_id);
5647 /* Add a constraint for a result decl that is passed by reference. */
5648 if (DECL_RESULT (cfun->decl)
5649 && DECL_BY_REFERENCE (DECL_RESULT (cfun->decl)))
5651 varinfo_t p, result_vi = get_vi_for_tree (DECL_RESULT (cfun->decl));
5653 for (p = result_vi; p; p = p->next)
5654 make_constraint_from (p, nonlocal_id);
5657 /* Add a constraint for the incoming static chain parameter. */
5658 if (cfun->static_chain_decl != NULL_TREE)
5660 varinfo_t p, chain_vi = get_vi_for_tree (cfun->static_chain_decl);
5662 for (p = chain_vi; p; p = p->next)
5663 make_constraint_from (p, nonlocal_id);
5667 /* Structure used to put solution bitmaps in a hashtable so they can
5668 be shared among variables with the same points-to set. */
5670 typedef struct shared_bitmap_info
5674 } *shared_bitmap_info_t;
5675 typedef const struct shared_bitmap_info *const_shared_bitmap_info_t;
5677 static htab_t shared_bitmap_table;
5679 /* Hash function for a shared_bitmap_info_t */
5682 shared_bitmap_hash (const void *p)
5684 const_shared_bitmap_info_t const bi = (const_shared_bitmap_info_t) p;
5685 return bi->hashcode;
5688 /* Equality function for two shared_bitmap_info_t's. */
5691 shared_bitmap_eq (const void *p1, const void *p2)
5693 const_shared_bitmap_info_t const sbi1 = (const_shared_bitmap_info_t) p1;
5694 const_shared_bitmap_info_t const sbi2 = (const_shared_bitmap_info_t) p2;
5695 return bitmap_equal_p (sbi1->pt_vars, sbi2->pt_vars);
5698 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
5699 existing instance if there is one, NULL otherwise. */
5702 shared_bitmap_lookup (bitmap pt_vars)
5705 struct shared_bitmap_info sbi;
5707 sbi.pt_vars = pt_vars;
5708 sbi.hashcode = bitmap_hash (pt_vars);
5710 slot = htab_find_slot_with_hash (shared_bitmap_table, &sbi,
5711 sbi.hashcode, NO_INSERT);
5715 return ((shared_bitmap_info_t) *slot)->pt_vars;
5719 /* Add a bitmap to the shared bitmap hashtable. */
5722 shared_bitmap_add (bitmap pt_vars)
5725 shared_bitmap_info_t sbi = XNEW (struct shared_bitmap_info);
5727 sbi->pt_vars = pt_vars;
5728 sbi->hashcode = bitmap_hash (pt_vars);
5730 slot = htab_find_slot_with_hash (shared_bitmap_table, sbi,
5731 sbi->hashcode, INSERT);
5732 gcc_assert (!*slot);
5733 *slot = (void *) sbi;
5737 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
5740 set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt)
5745 EXECUTE_IF_SET_IN_BITMAP (from, 0, i, bi)
5747 varinfo_t vi = get_varinfo (i);
5749 /* The only artificial variables that are allowed in a may-alias
5750 set are heap variables. */
5751 if (vi->is_artificial_var && !vi->is_heap_var)
5754 if (TREE_CODE (vi->decl) == VAR_DECL
5755 || TREE_CODE (vi->decl) == PARM_DECL
5756 || TREE_CODE (vi->decl) == RESULT_DECL)
5758 /* If we are in IPA mode we will not recompute points-to
5759 sets after inlining so make sure they stay valid. */
5761 && !DECL_PT_UID_SET_P (vi->decl))
5762 SET_DECL_PT_UID (vi->decl, DECL_UID (vi->decl));
5764 /* Add the decl to the points-to set. Note that the points-to
5765 set contains global variables. */
5766 bitmap_set_bit (into, DECL_PT_UID (vi->decl));
5767 if (vi->is_global_var)
5768 pt->vars_contains_global = true;
5774 /* Compute the points-to solution *PT for the variable VI. */
5777 find_what_var_points_to (varinfo_t orig_vi, struct pt_solution *pt)
5781 bitmap finished_solution;
5785 memset (pt, 0, sizeof (struct pt_solution));
5787 /* This variable may have been collapsed, let's get the real
5789 vi = get_varinfo (find (orig_vi->id));
5791 /* Translate artificial variables into SSA_NAME_PTR_INFO
5793 EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, i, bi)
5795 varinfo_t vi = get_varinfo (i);
5797 if (vi->is_artificial_var)
5799 if (vi->id == nothing_id)
5801 else if (vi->id == escaped_id)
5804 pt->ipa_escaped = 1;
5808 else if (vi->id == nonlocal_id)
5810 else if (vi->is_heap_var)
5811 /* We represent heapvars in the points-to set properly. */
5813 else if (vi->id == readonly_id)
5816 else if (vi->id == anything_id
5817 || vi->id == integer_id)
5822 /* Instead of doing extra work, simply do not create
5823 elaborate points-to information for pt_anything pointers. */
5827 /* Share the final set of variables when possible. */
5828 finished_solution = BITMAP_GGC_ALLOC ();
5829 stats.points_to_sets_created++;
5831 set_uids_in_ptset (finished_solution, vi->solution, pt);
5832 result = shared_bitmap_lookup (finished_solution);
5835 shared_bitmap_add (finished_solution);
5836 pt->vars = finished_solution;
5841 bitmap_clear (finished_solution);
5845 /* Given a pointer variable P, fill in its points-to set. */
5848 find_what_p_points_to (tree p)
5850 struct ptr_info_def *pi;
5854 /* For parameters, get at the points-to set for the actual parm
5856 if (TREE_CODE (p) == SSA_NAME
5857 && (TREE_CODE (SSA_NAME_VAR (p)) == PARM_DECL
5858 || TREE_CODE (SSA_NAME_VAR (p)) == RESULT_DECL)
5859 && SSA_NAME_IS_DEFAULT_DEF (p))
5860 lookup_p = SSA_NAME_VAR (p);
5862 vi = lookup_vi_for_tree (lookup_p);
5866 pi = get_ptr_info (p);
5867 find_what_var_points_to (vi, &pi->pt);
5871 /* Query statistics for points-to solutions. */
5874 unsigned HOST_WIDE_INT pt_solution_includes_may_alias;
5875 unsigned HOST_WIDE_INT pt_solution_includes_no_alias;
5876 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias;
5877 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias;
5881 dump_pta_stats (FILE *s)
5883 fprintf (s, "\nPTA query stats:\n");
5884 fprintf (s, " pt_solution_includes: "
5885 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5886 HOST_WIDE_INT_PRINT_DEC" queries\n",
5887 pta_stats.pt_solution_includes_no_alias,
5888 pta_stats.pt_solution_includes_no_alias
5889 + pta_stats.pt_solution_includes_may_alias);
5890 fprintf (s, " pt_solutions_intersect: "
5891 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
5892 HOST_WIDE_INT_PRINT_DEC" queries\n",
5893 pta_stats.pt_solutions_intersect_no_alias,
5894 pta_stats.pt_solutions_intersect_no_alias
5895 + pta_stats.pt_solutions_intersect_may_alias);
5899 /* Reset the points-to solution *PT to a conservative default
5900 (point to anything). */
5903 pt_solution_reset (struct pt_solution *pt)
5905 memset (pt, 0, sizeof (struct pt_solution));
5906 pt->anything = true;
5909 /* Set the points-to solution *PT to point only to the variables
5910 in VARS. VARS_CONTAINS_GLOBAL specifies whether that contains
5911 global variables and VARS_CONTAINS_RESTRICT specifies whether
5912 it contains restrict tag variables. */
5915 pt_solution_set (struct pt_solution *pt, bitmap vars, bool vars_contains_global)
5917 memset (pt, 0, sizeof (struct pt_solution));
5919 pt->vars_contains_global = vars_contains_global;
5922 /* Set the points-to solution *PT to point only to the variable VAR. */
5925 pt_solution_set_var (struct pt_solution *pt, tree var)
5927 memset (pt, 0, sizeof (struct pt_solution));
5928 pt->vars = BITMAP_GGC_ALLOC ();
5929 bitmap_set_bit (pt->vars, DECL_PT_UID (var));
5930 pt->vars_contains_global = is_global_var (var);
5933 /* Computes the union of the points-to solutions *DEST and *SRC and
5934 stores the result in *DEST. This changes the points-to bitmap
5935 of *DEST and thus may not be used if that might be shared.
5936 The points-to bitmap of *SRC and *DEST will not be shared after
5937 this function if they were not before. */
5940 pt_solution_ior_into (struct pt_solution *dest, struct pt_solution *src)
5942 dest->anything |= src->anything;
5945 pt_solution_reset (dest);
5949 dest->nonlocal |= src->nonlocal;
5950 dest->escaped |= src->escaped;
5951 dest->ipa_escaped |= src->ipa_escaped;
5952 dest->null |= src->null;
5953 dest->vars_contains_global |= src->vars_contains_global;
5958 dest->vars = BITMAP_GGC_ALLOC ();
5959 bitmap_ior_into (dest->vars, src->vars);
5962 /* Return true if the points-to solution *PT is empty. */
5965 pt_solution_empty_p (struct pt_solution *pt)
5972 && !bitmap_empty_p (pt->vars))
5975 /* If the solution includes ESCAPED, check if that is empty. */
5977 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
5980 /* If the solution includes ESCAPED, check if that is empty. */
5982 && !pt_solution_empty_p (&ipa_escaped_pt))
5988 /* Return true if the points-to solution *PT only point to a single var, and
5989 return the var uid in *UID. */
5992 pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid)
5994 if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped
5995 || pt->null || pt->vars == NULL
5996 || !bitmap_single_bit_set_p (pt->vars))
5999 *uid = bitmap_first_set_bit (pt->vars);
6003 /* Return true if the points-to solution *PT includes global memory. */
6006 pt_solution_includes_global (struct pt_solution *pt)
6010 || pt->vars_contains_global)
6014 return pt_solution_includes_global (&cfun->gimple_df->escaped);
6016 if (pt->ipa_escaped)
6017 return pt_solution_includes_global (&ipa_escaped_pt);
6019 /* ??? This predicate is not correct for the IPA-PTA solution
6020 as we do not properly distinguish between unit escape points
6021 and global variables. */
6022 if (cfun->gimple_df->ipa_pta)
6028 /* Return true if the points-to solution *PT includes the variable
6029 declaration DECL. */
6032 pt_solution_includes_1 (struct pt_solution *pt, const_tree decl)
6038 && is_global_var (decl))
6042 && bitmap_bit_p (pt->vars, DECL_PT_UID (decl)))
6045 /* If the solution includes ESCAPED, check it. */
6047 && pt_solution_includes_1 (&cfun->gimple_df->escaped, decl))
6050 /* If the solution includes ESCAPED, check it. */
6052 && pt_solution_includes_1 (&ipa_escaped_pt, decl))
6059 pt_solution_includes (struct pt_solution *pt, const_tree decl)
6061 bool res = pt_solution_includes_1 (pt, decl);
6063 ++pta_stats.pt_solution_includes_may_alias;
6065 ++pta_stats.pt_solution_includes_no_alias;
6069 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
6073 pt_solutions_intersect_1 (struct pt_solution *pt1, struct pt_solution *pt2)
6075 if (pt1->anything || pt2->anything)
6078 /* If either points to unknown global memory and the other points to
6079 any global memory they alias. */
6082 || pt2->vars_contains_global))
6084 && pt1->vars_contains_global))
6087 /* Check the escaped solution if required. */
6088 if ((pt1->escaped || pt2->escaped)
6089 && !pt_solution_empty_p (&cfun->gimple_df->escaped))
6091 /* If both point to escaped memory and that solution
6092 is not empty they alias. */
6093 if (pt1->escaped && pt2->escaped)
6096 /* If either points to escaped memory see if the escaped solution
6097 intersects with the other. */
6099 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt2))
6101 && pt_solutions_intersect_1 (&cfun->gimple_df->escaped, pt1)))
6105 /* Check the escaped solution if required.
6106 ??? Do we need to check the local against the IPA escaped sets? */
6107 if ((pt1->ipa_escaped || pt2->ipa_escaped)
6108 && !pt_solution_empty_p (&ipa_escaped_pt))
6110 /* If both point to escaped memory and that solution
6111 is not empty they alias. */
6112 if (pt1->ipa_escaped && pt2->ipa_escaped)
6115 /* If either points to escaped memory see if the escaped solution
6116 intersects with the other. */
6117 if ((pt1->ipa_escaped
6118 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt2))
6119 || (pt2->ipa_escaped
6120 && pt_solutions_intersect_1 (&ipa_escaped_pt, pt1)))
6124 /* Now both pointers alias if their points-to solution intersects. */
6127 && bitmap_intersect_p (pt1->vars, pt2->vars));
6131 pt_solutions_intersect (struct pt_solution *pt1, struct pt_solution *pt2)
6133 bool res = pt_solutions_intersect_1 (pt1, pt2);
6135 ++pta_stats.pt_solutions_intersect_may_alias;
6137 ++pta_stats.pt_solutions_intersect_no_alias;
6142 /* Dump points-to information to OUTFILE. */
6145 dump_sa_points_to_info (FILE *outfile)
6149 fprintf (outfile, "\nPoints-to sets\n\n");
6151 if (dump_flags & TDF_STATS)
6153 fprintf (outfile, "Stats:\n");
6154 fprintf (outfile, "Total vars: %d\n", stats.total_vars);
6155 fprintf (outfile, "Non-pointer vars: %d\n",
6156 stats.nonpointer_vars);
6157 fprintf (outfile, "Statically unified vars: %d\n",
6158 stats.unified_vars_static);
6159 fprintf (outfile, "Dynamically unified vars: %d\n",
6160 stats.unified_vars_dynamic);
6161 fprintf (outfile, "Iterations: %d\n", stats.iterations);
6162 fprintf (outfile, "Number of edges: %d\n", stats.num_edges);
6163 fprintf (outfile, "Number of implicit edges: %d\n",
6164 stats.num_implicit_edges);
6167 for (i = 0; i < VEC_length (varinfo_t, varmap); i++)
6169 varinfo_t vi = get_varinfo (i);
6170 if (!vi->may_have_pointers)
6172 dump_solution_for_var (outfile, i);
6177 /* Debug points-to information to stderr. */
6180 debug_sa_points_to_info (void)
6182 dump_sa_points_to_info (stderr);
6186 /* Initialize the always-existing constraint variables for NULL
6187 ANYTHING, READONLY, and INTEGER */
6190 init_base_vars (void)
6192 struct constraint_expr lhs, rhs;
6193 varinfo_t var_anything;
6194 varinfo_t var_nothing;
6195 varinfo_t var_readonly;
6196 varinfo_t var_escaped;
6197 varinfo_t var_nonlocal;
6198 varinfo_t var_storedanything;
6199 varinfo_t var_integer;
6201 /* Create the NULL variable, used to represent that a variable points
6203 var_nothing = new_var_info (NULL_TREE, "NULL");
6204 gcc_assert (var_nothing->id == nothing_id);
6205 var_nothing->is_artificial_var = 1;
6206 var_nothing->offset = 0;
6207 var_nothing->size = ~0;
6208 var_nothing->fullsize = ~0;
6209 var_nothing->is_special_var = 1;
6210 var_nothing->may_have_pointers = 0;
6211 var_nothing->is_global_var = 0;
6213 /* Create the ANYTHING variable, used to represent that a variable
6214 points to some unknown piece of memory. */
6215 var_anything = new_var_info (NULL_TREE, "ANYTHING");
6216 gcc_assert (var_anything->id == anything_id);
6217 var_anything->is_artificial_var = 1;
6218 var_anything->size = ~0;
6219 var_anything->offset = 0;
6220 var_anything->next = NULL;
6221 var_anything->fullsize = ~0;
6222 var_anything->is_special_var = 1;
6224 /* Anything points to anything. This makes deref constraints just
6225 work in the presence of linked list and other p = *p type loops,
6226 by saying that *ANYTHING = ANYTHING. */
6228 lhs.var = anything_id;
6230 rhs.type = ADDRESSOF;
6231 rhs.var = anything_id;
6234 /* This specifically does not use process_constraint because
6235 process_constraint ignores all anything = anything constraints, since all
6236 but this one are redundant. */
6237 VEC_safe_push (constraint_t, heap, constraints, new_constraint (lhs, rhs));
6239 /* Create the READONLY variable, used to represent that a variable
6240 points to readonly memory. */
6241 var_readonly = new_var_info (NULL_TREE, "READONLY");
6242 gcc_assert (var_readonly->id == readonly_id);
6243 var_readonly->is_artificial_var = 1;
6244 var_readonly->offset = 0;
6245 var_readonly->size = ~0;
6246 var_readonly->fullsize = ~0;
6247 var_readonly->next = NULL;
6248 var_readonly->is_special_var = 1;
6250 /* readonly memory points to anything, in order to make deref
6251 easier. In reality, it points to anything the particular
6252 readonly variable can point to, but we don't track this
6255 lhs.var = readonly_id;
6257 rhs.type = ADDRESSOF;
6258 rhs.var = readonly_id; /* FIXME */
6260 process_constraint (new_constraint (lhs, rhs));
6262 /* Create the ESCAPED variable, used to represent the set of escaped
6264 var_escaped = new_var_info (NULL_TREE, "ESCAPED");
6265 gcc_assert (var_escaped->id == escaped_id);
6266 var_escaped->is_artificial_var = 1;
6267 var_escaped->offset = 0;
6268 var_escaped->size = ~0;
6269 var_escaped->fullsize = ~0;
6270 var_escaped->is_special_var = 0;
6272 /* Create the NONLOCAL variable, used to represent the set of nonlocal
6274 var_nonlocal = new_var_info (NULL_TREE, "NONLOCAL");
6275 gcc_assert (var_nonlocal->id == nonlocal_id);
6276 var_nonlocal->is_artificial_var = 1;
6277 var_nonlocal->offset = 0;
6278 var_nonlocal->size = ~0;
6279 var_nonlocal->fullsize = ~0;
6280 var_nonlocal->is_special_var = 1;
6282 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
6284 lhs.var = escaped_id;
6287 rhs.var = escaped_id;
6289 process_constraint (new_constraint (lhs, rhs));
6291 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
6292 whole variable escapes. */
6294 lhs.var = escaped_id;
6297 rhs.var = escaped_id;
6298 rhs.offset = UNKNOWN_OFFSET;
6299 process_constraint (new_constraint (lhs, rhs));
6301 /* *ESCAPED = NONLOCAL. This is true because we have to assume
6302 everything pointed to by escaped points to what global memory can
6305 lhs.var = escaped_id;
6308 rhs.var = nonlocal_id;
6310 process_constraint (new_constraint (lhs, rhs));
6312 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
6313 global memory may point to global memory and escaped memory. */
6315 lhs.var = nonlocal_id;
6317 rhs.type = ADDRESSOF;
6318 rhs.var = nonlocal_id;
6320 process_constraint (new_constraint (lhs, rhs));
6321 rhs.type = ADDRESSOF;
6322 rhs.var = escaped_id;
6324 process_constraint (new_constraint (lhs, rhs));
6326 /* Create the STOREDANYTHING variable, used to represent the set of
6327 variables stored to *ANYTHING. */
6328 var_storedanything = new_var_info (NULL_TREE, "STOREDANYTHING");
6329 gcc_assert (var_storedanything->id == storedanything_id);
6330 var_storedanything->is_artificial_var = 1;
6331 var_storedanything->offset = 0;
6332 var_storedanything->size = ~0;
6333 var_storedanything->fullsize = ~0;
6334 var_storedanything->is_special_var = 0;
6336 /* Create the INTEGER variable, used to represent that a variable points
6337 to what an INTEGER "points to". */
6338 var_integer = new_var_info (NULL_TREE, "INTEGER");
6339 gcc_assert (var_integer->id == integer_id);
6340 var_integer->is_artificial_var = 1;
6341 var_integer->size = ~0;
6342 var_integer->fullsize = ~0;
6343 var_integer->offset = 0;
6344 var_integer->next = NULL;
6345 var_integer->is_special_var = 1;
6347 /* INTEGER = ANYTHING, because we don't know where a dereference of
6348 a random integer will point to. */
6350 lhs.var = integer_id;
6352 rhs.type = ADDRESSOF;
6353 rhs.var = anything_id;
6355 process_constraint (new_constraint (lhs, rhs));
6358 /* Initialize things necessary to perform PTA */
6361 init_alias_vars (void)
6363 use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
6365 bitmap_obstack_initialize (&pta_obstack);
6366 bitmap_obstack_initialize (&oldpta_obstack);
6367 bitmap_obstack_initialize (&predbitmap_obstack);
6369 constraint_pool = create_alloc_pool ("Constraint pool",
6370 sizeof (struct constraint), 30);
6371 variable_info_pool = create_alloc_pool ("Variable info pool",
6372 sizeof (struct variable_info), 30);
6373 constraints = VEC_alloc (constraint_t, heap, 8);
6374 varmap = VEC_alloc (varinfo_t, heap, 8);
6375 vi_for_tree = pointer_map_create ();
6376 call_stmt_vars = pointer_map_create ();
6378 memset (&stats, 0, sizeof (stats));
6379 shared_bitmap_table = htab_create (511, shared_bitmap_hash,
6380 shared_bitmap_eq, free);
6383 gcc_obstack_init (&fake_var_decl_obstack);
6386 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
6387 predecessor edges. */
6390 remove_preds_and_fake_succs (constraint_graph_t graph)
6394 /* Clear the implicit ref and address nodes from the successor
6396 for (i = 0; i < FIRST_REF_NODE; i++)
6398 if (graph->succs[i])
6399 bitmap_clear_range (graph->succs[i], FIRST_REF_NODE,
6400 FIRST_REF_NODE * 2);
6403 /* Free the successor list for the non-ref nodes. */
6404 for (i = FIRST_REF_NODE; i < graph->size; i++)
6406 if (graph->succs[i])
6407 BITMAP_FREE (graph->succs[i]);
6410 /* Now reallocate the size of the successor list as, and blow away
6411 the predecessor bitmaps. */
6412 graph->size = VEC_length (varinfo_t, varmap);
6413 graph->succs = XRESIZEVEC (bitmap, graph->succs, graph->size);
6415 free (graph->implicit_preds);
6416 graph->implicit_preds = NULL;
6417 free (graph->preds);
6418 graph->preds = NULL;
6419 bitmap_obstack_release (&predbitmap_obstack);
6422 /* Solve the constraint set. */
6425 solve_constraints (void)
6427 struct scc_info *si;
6431 "\nCollapsing static cycles and doing variable "
6434 init_graph (VEC_length (varinfo_t, varmap) * 2);
6437 fprintf (dump_file, "Building predecessor graph\n");
6438 build_pred_graph ();
6441 fprintf (dump_file, "Detecting pointer and location "
6443 si = perform_var_substitution (graph);
6446 fprintf (dump_file, "Rewriting constraints and unifying "
6448 rewrite_constraints (graph, si);
6450 build_succ_graph ();
6452 free_var_substitution_info (si);
6454 /* Attach complex constraints to graph nodes. */
6455 move_complex_constraints (graph);
6458 fprintf (dump_file, "Uniting pointer but not location equivalent "
6460 unite_pointer_equivalences (graph);
6463 fprintf (dump_file, "Finding indirect cycles\n");
6464 find_indirect_cycles (graph);
6466 /* Implicit nodes and predecessors are no longer necessary at this
6468 remove_preds_and_fake_succs (graph);
6470 if (dump_file && (dump_flags & TDF_GRAPH))
6472 fprintf (dump_file, "\n\n// The constraint graph before solve-graph "
6473 "in dot format:\n");
6474 dump_constraint_graph (dump_file);
6475 fprintf (dump_file, "\n\n");
6479 fprintf (dump_file, "Solving graph\n");
6481 solve_graph (graph);
6483 if (dump_file && (dump_flags & TDF_GRAPH))
6485 fprintf (dump_file, "\n\n// The constraint graph after solve-graph "
6486 "in dot format:\n");
6487 dump_constraint_graph (dump_file);
6488 fprintf (dump_file, "\n\n");
6492 dump_sa_points_to_info (dump_file);
6495 /* Create points-to sets for the current function. See the comments
6496 at the start of the file for an algorithmic overview. */
6499 compute_points_to_sets (void)
6505 timevar_push (TV_TREE_PTA);
6509 intra_create_variable_infos ();
6511 /* Now walk all statements and build the constraint set. */
6514 gimple_stmt_iterator gsi;
6516 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6518 gimple phi = gsi_stmt (gsi);
6520 if (is_gimple_reg (gimple_phi_result (phi)))
6521 find_func_aliases (phi);
6524 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6526 gimple stmt = gsi_stmt (gsi);
6528 find_func_aliases (stmt);
6534 fprintf (dump_file, "Points-to analysis\n\nConstraints:\n\n");
6535 dump_constraints (dump_file, 0);
6538 /* From the constraints compute the points-to sets. */
6539 solve_constraints ();
6541 /* Compute the points-to set for ESCAPED used for call-clobber analysis. */
6542 find_what_var_points_to (get_varinfo (escaped_id),
6543 &cfun->gimple_df->escaped);
6545 /* Make sure the ESCAPED solution (which is used as placeholder in
6546 other solutions) does not reference itself. This simplifies
6547 points-to solution queries. */
6548 cfun->gimple_df->escaped.escaped = 0;
6550 /* Mark escaped HEAP variables as global. */
6551 FOR_EACH_VEC_ELT (varinfo_t, varmap, i, vi)
6553 && !vi->is_global_var)
6554 DECL_EXTERNAL (vi->decl) = vi->is_global_var
6555 = pt_solution_includes (&cfun->gimple_df->escaped, vi->decl);
6557 /* Compute the points-to sets for pointer SSA_NAMEs. */
6558 for (i = 0; i < num_ssa_names; ++i)
6560 tree ptr = ssa_name (i);
6562 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6563 find_what_p_points_to (ptr);
6566 /* Compute the call-used/clobbered sets. */
6569 gimple_stmt_iterator gsi;
6571 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6573 gimple stmt = gsi_stmt (gsi);
6574 struct pt_solution *pt;
6575 if (!is_gimple_call (stmt))
6578 pt = gimple_call_use_set (stmt);
6579 if (gimple_call_flags (stmt) & ECF_CONST)
6580 memset (pt, 0, sizeof (struct pt_solution));
6581 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
6583 find_what_var_points_to (vi, pt);
6584 /* Escaped (and thus nonlocal) variables are always
6585 implicitly used by calls. */
6586 /* ??? ESCAPED can be empty even though NONLOCAL
6593 /* If there is nothing special about this call then
6594 we have made everything that is used also escape. */
6595 *pt = cfun->gimple_df->escaped;
6599 pt = gimple_call_clobber_set (stmt);
6600 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
6601 memset (pt, 0, sizeof (struct pt_solution));
6602 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
6604 find_what_var_points_to (vi, pt);
6605 /* Escaped (and thus nonlocal) variables are always
6606 implicitly clobbered by calls. */
6607 /* ??? ESCAPED can be empty even though NONLOCAL
6614 /* If there is nothing special about this call then
6615 we have made everything that is used also escape. */
6616 *pt = cfun->gimple_df->escaped;
6622 timevar_pop (TV_TREE_PTA);
6626 /* Delete created points-to sets. */
6629 delete_points_to_sets (void)
6633 htab_delete (shared_bitmap_table);
6634 if (dump_file && (dump_flags & TDF_STATS))
6635 fprintf (dump_file, "Points to sets created:%d\n",
6636 stats.points_to_sets_created);
6638 pointer_map_destroy (vi_for_tree);
6639 pointer_map_destroy (call_stmt_vars);
6640 bitmap_obstack_release (&pta_obstack);
6641 VEC_free (constraint_t, heap, constraints);
6643 for (i = 0; i < graph->size; i++)
6644 VEC_free (constraint_t, heap, graph->complex[i]);
6645 free (graph->complex);
6648 free (graph->succs);
6650 free (graph->pe_rep);
6651 free (graph->indirect_cycles);
6654 VEC_free (varinfo_t, heap, varmap);
6655 free_alloc_pool (variable_info_pool);
6656 free_alloc_pool (constraint_pool);
6658 obstack_free (&fake_var_decl_obstack, NULL);
6662 /* Compute points-to information for every SSA_NAME pointer in the
6663 current function and compute the transitive closure of escaped
6664 variables to re-initialize the call-clobber states of local variables. */
6667 compute_may_aliases (void)
6669 if (cfun->gimple_df->ipa_pta)
6673 fprintf (dump_file, "\nNot re-computing points-to information "
6674 "because IPA points-to information is available.\n\n");
6676 /* But still dump what we have remaining it. */
6677 dump_alias_info (dump_file);
6679 if (dump_flags & TDF_DETAILS)
6680 dump_referenced_vars (dump_file);
6686 /* For each pointer P_i, determine the sets of variables that P_i may
6687 point-to. Compute the reachability set of escaped and call-used
6689 compute_points_to_sets ();
6691 /* Debugging dumps. */
6694 dump_alias_info (dump_file);
6696 if (dump_flags & TDF_DETAILS)
6697 dump_referenced_vars (dump_file);
6700 /* Deallocate memory used by aliasing data structures and the internal
6701 points-to solution. */
6702 delete_points_to_sets ();
6704 gcc_assert (!need_ssa_update_p (cfun));
6710 gate_tree_pta (void)
6712 return flag_tree_pta;
6715 /* A dummy pass to cause points-to information to be computed via
6716 TODO_rebuild_alias. */
6718 struct gimple_opt_pass pass_build_alias =
6723 gate_tree_pta, /* gate */
6727 0, /* static_pass_number */
6728 TV_NONE, /* tv_id */
6729 PROP_cfg | PROP_ssa, /* properties_required */
6730 0, /* properties_provided */
6731 0, /* properties_destroyed */
6732 0, /* todo_flags_start */
6733 TODO_rebuild_alias /* todo_flags_finish */
6737 /* A dummy pass to cause points-to information to be computed via
6738 TODO_rebuild_alias. */
6740 struct gimple_opt_pass pass_build_ealias =
6744 "ealias", /* name */
6745 gate_tree_pta, /* gate */
6749 0, /* static_pass_number */
6750 TV_NONE, /* tv_id */
6751 PROP_cfg | PROP_ssa, /* properties_required */
6752 0, /* properties_provided */
6753 0, /* properties_destroyed */
6754 0, /* todo_flags_start */
6755 TODO_rebuild_alias /* todo_flags_finish */
6760 /* Return true if we should execute IPA PTA. */
6766 /* Don't bother doing anything if the program has errors. */
6770 /* IPA PTA solutions for ESCAPED. */
6771 struct pt_solution ipa_escaped_pt
6772 = { true, false, false, false, false, false, NULL };
6774 /* Associate node with varinfo DATA. Worker for
6775 cgraph_for_node_and_aliases. */
6777 associate_varinfo_to_alias (struct cgraph_node *node, void *data)
6779 if (node->alias || node->thunk.thunk_p)
6780 insert_vi_for_tree (node->decl, (varinfo_t)data);
6784 /* Execute the driver for IPA PTA. */
6786 ipa_pta_execute (void)
6788 struct cgraph_node *node;
6789 struct varpool_node *var;
6796 if (dump_file && (dump_flags & TDF_DETAILS))
6798 dump_cgraph (dump_file);
6799 fprintf (dump_file, "\n");
6802 /* Build the constraints. */
6803 for (node = cgraph_nodes; node; node = node->next)
6806 /* Nodes without a body are not interesting. Especially do not
6807 visit clones at this point for now - we get duplicate decls
6808 there for inline clones at least. */
6809 if (!cgraph_function_with_gimple_body_p (node))
6812 gcc_assert (!node->clone_of);
6814 vi = create_function_info_for (node->decl,
6815 alias_get_name (node->decl));
6816 cgraph_for_node_and_aliases (node, associate_varinfo_to_alias, vi, true);
6819 /* Create constraints for global variables and their initializers. */
6820 for (var = varpool_nodes; var; var = var->next)
6825 get_vi_for_tree (var->decl);
6831 "Generating constraints for global initializers\n\n");
6832 dump_constraints (dump_file, 0);
6833 fprintf (dump_file, "\n");
6835 from = VEC_length (constraint_t, constraints);
6837 for (node = cgraph_nodes; node; node = node->next)
6839 struct function *func;
6843 /* Nodes without a body are not interesting. */
6844 if (!cgraph_function_with_gimple_body_p (node))
6850 "Generating constraints for %s", cgraph_node_name (node));
6851 if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
6852 fprintf (dump_file, " (%s)",
6853 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
6854 fprintf (dump_file, "\n");
6857 func = DECL_STRUCT_FUNCTION (node->decl);
6858 old_func_decl = current_function_decl;
6860 current_function_decl = node->decl;
6862 /* For externally visible or attribute used annotated functions use
6863 local constraints for their arguments.
6864 For local functions we see all callers and thus do not need initial
6865 constraints for parameters. */
6866 if (node->reachable_from_other_partition
6867 || node->local.externally_visible
6870 intra_create_variable_infos ();
6872 /* We also need to make function return values escape. Nothing
6873 escapes by returning from main though. */
6874 if (!MAIN_NAME_P (DECL_NAME (node->decl)))
6877 fi = lookup_vi_for_tree (node->decl);
6878 rvi = first_vi_for_offset (fi, fi_result);
6879 if (rvi && rvi->offset == fi_result)
6881 struct constraint_expr includes;
6882 struct constraint_expr var;
6883 includes.var = escaped_id;
6884 includes.offset = 0;
6885 includes.type = SCALAR;
6889 process_constraint (new_constraint (includes, var));
6894 /* Build constriants for the function body. */
6895 FOR_EACH_BB_FN (bb, func)
6897 gimple_stmt_iterator gsi;
6899 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
6902 gimple phi = gsi_stmt (gsi);
6904 if (is_gimple_reg (gimple_phi_result (phi)))
6905 find_func_aliases (phi);
6908 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6910 gimple stmt = gsi_stmt (gsi);
6912 find_func_aliases (stmt);
6913 find_func_clobbers (stmt);
6917 current_function_decl = old_func_decl;
6922 fprintf (dump_file, "\n");
6923 dump_constraints (dump_file, from);
6924 fprintf (dump_file, "\n");
6926 from = VEC_length (constraint_t, constraints);
6929 /* From the constraints compute the points-to sets. */
6930 solve_constraints ();
6932 /* Compute the global points-to sets for ESCAPED.
6933 ??? Note that the computed escape set is not correct
6934 for the whole unit as we fail to consider graph edges to
6935 externally visible functions. */
6936 find_what_var_points_to (get_varinfo (escaped_id), &ipa_escaped_pt);
6938 /* Make sure the ESCAPED solution (which is used as placeholder in
6939 other solutions) does not reference itself. This simplifies
6940 points-to solution queries. */
6941 ipa_escaped_pt.ipa_escaped = 0;
6943 /* Assign the points-to sets to the SSA names in the unit. */
6944 for (node = cgraph_nodes; node; node = node->next)
6947 struct function *fn;
6951 struct pt_solution uses, clobbers;
6952 struct cgraph_edge *e;
6954 /* Nodes without a body are not interesting. */
6955 if (!cgraph_function_with_gimple_body_p (node))
6958 fn = DECL_STRUCT_FUNCTION (node->decl);
6960 /* Compute the points-to sets for pointer SSA_NAMEs. */
6961 FOR_EACH_VEC_ELT (tree, fn->gimple_df->ssa_names, i, ptr)
6964 && POINTER_TYPE_P (TREE_TYPE (ptr)))
6965 find_what_p_points_to (ptr);
6968 /* Compute the call-use and call-clobber sets for all direct calls. */
6969 fi = lookup_vi_for_tree (node->decl);
6970 gcc_assert (fi->is_fn_info);
6971 find_what_var_points_to (first_vi_for_offset (fi, fi_clobbers),
6973 find_what_var_points_to (first_vi_for_offset (fi, fi_uses), &uses);
6974 for (e = node->callers; e; e = e->next_caller)
6979 *gimple_call_clobber_set (e->call_stmt) = clobbers;
6980 *gimple_call_use_set (e->call_stmt) = uses;
6983 /* Compute the call-use and call-clobber sets for indirect calls
6984 and calls to external functions. */
6985 FOR_EACH_BB_FN (bb, fn)
6987 gimple_stmt_iterator gsi;
6989 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
6991 gimple stmt = gsi_stmt (gsi);
6992 struct pt_solution *pt;
6996 if (!is_gimple_call (stmt))
6999 /* Handle direct calls to external functions. */
7000 decl = gimple_call_fndecl (stmt);
7002 && (!(fi = lookup_vi_for_tree (decl))
7003 || !fi->is_fn_info))
7005 pt = gimple_call_use_set (stmt);
7006 if (gimple_call_flags (stmt) & ECF_CONST)
7007 memset (pt, 0, sizeof (struct pt_solution));
7008 else if ((vi = lookup_call_use_vi (stmt)) != NULL)
7010 find_what_var_points_to (vi, pt);
7011 /* Escaped (and thus nonlocal) variables are always
7012 implicitly used by calls. */
7013 /* ??? ESCAPED can be empty even though NONLOCAL
7016 pt->ipa_escaped = 1;
7020 /* If there is nothing special about this call then
7021 we have made everything that is used also escape. */
7022 *pt = ipa_escaped_pt;
7026 pt = gimple_call_clobber_set (stmt);
7027 if (gimple_call_flags (stmt) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
7028 memset (pt, 0, sizeof (struct pt_solution));
7029 else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
7031 find_what_var_points_to (vi, pt);
7032 /* Escaped (and thus nonlocal) variables are always
7033 implicitly clobbered by calls. */
7034 /* ??? ESCAPED can be empty even though NONLOCAL
7037 pt->ipa_escaped = 1;
7041 /* If there is nothing special about this call then
7042 we have made everything that is used also escape. */
7043 *pt = ipa_escaped_pt;
7048 /* Handle indirect calls. */
7050 && (fi = get_fi_for_callee (stmt)))
7052 /* We need to accumulate all clobbers/uses of all possible
7054 fi = get_varinfo (find (fi->id));
7055 /* If we cannot constrain the set of functions we'll end up
7056 calling we end up using/clobbering everything. */
7057 if (bitmap_bit_p (fi->solution, anything_id)
7058 || bitmap_bit_p (fi->solution, nonlocal_id)
7059 || bitmap_bit_p (fi->solution, escaped_id))
7061 pt_solution_reset (gimple_call_clobber_set (stmt));
7062 pt_solution_reset (gimple_call_use_set (stmt));
7068 struct pt_solution *uses, *clobbers;
7070 uses = gimple_call_use_set (stmt);
7071 clobbers = gimple_call_clobber_set (stmt);
7072 memset (uses, 0, sizeof (struct pt_solution));
7073 memset (clobbers, 0, sizeof (struct pt_solution));
7074 EXECUTE_IF_SET_IN_BITMAP (fi->solution, 0, i, bi)
7076 struct pt_solution sol;
7078 vi = get_varinfo (i);
7079 if (!vi->is_fn_info)
7081 /* ??? We could be more precise here? */
7083 uses->ipa_escaped = 1;
7084 clobbers->nonlocal = 1;
7085 clobbers->ipa_escaped = 1;
7089 if (!uses->anything)
7091 find_what_var_points_to
7092 (first_vi_for_offset (vi, fi_uses), &sol);
7093 pt_solution_ior_into (uses, &sol);
7095 if (!clobbers->anything)
7097 find_what_var_points_to
7098 (first_vi_for_offset (vi, fi_clobbers), &sol);
7099 pt_solution_ior_into (clobbers, &sol);
7107 fn->gimple_df->ipa_pta = true;
7110 delete_points_to_sets ();
7117 struct simple_ipa_opt_pass pass_ipa_pta =
7122 gate_ipa_pta, /* gate */
7123 ipa_pta_execute, /* execute */
7126 0, /* static_pass_number */
7127 TV_IPA_PTA, /* tv_id */
7128 0, /* properties_required */
7129 0, /* properties_provided */
7130 0, /* properties_destroyed */
7131 0, /* todo_flags_start */
7132 TODO_update_ssa /* todo_flags_finish */