1 /* Tree based points-to analysis
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
3 Contributed by Daniel Berlin <dberlin@dberlin.org>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
31 #include "hard-reg-set.h"
32 #include "basic-block.h"
35 #include "tree-flow.h"
36 #include "tree-inline.h"
38 #include "diagnostic.h"
44 #include "tree-pass.h"
46 #include "alloc-pool.h"
47 #include "splay-tree.h"
51 #include "pointer-set.h"
53 /* The idea behind this analyzer is to generate set constraints from the
54 program, then solve the resulting constraints in order to generate the
57 Set constraints are a way of modeling program analysis problems that
58 involve sets. They consist of an inclusion constraint language,
59 describing the variables (each variable is a set) and operations that
60 are involved on the variables, and a set of rules that derive facts
61 from these operations. To solve a system of set constraints, you derive
62 all possible facts under the rules, which gives you the correct sets
65 See "Efficient Field-sensitive pointer analysis for C" by "David
66 J. Pearce and Paul H. J. Kelly and Chris Hankin, at
67 http://citeseer.ist.psu.edu/pearce04efficient.html
69 Also see "Ultra-fast Aliasing Analysis using CLA: A Million Lines
70 of C Code in a Second" by ""Nevin Heintze and Olivier Tardieu" at
71 http://citeseer.ist.psu.edu/heintze01ultrafast.html
73 There are three types of real constraint expressions, DEREF,
74 ADDRESSOF, and SCALAR. Each constraint expression consists
75 of a constraint type, a variable, and an offset.
77 SCALAR is a constraint expression type used to represent x, whether
78 it appears on the LHS or the RHS of a statement.
79 DEREF is a constraint expression type used to represent *x, whether
80 it appears on the LHS or the RHS of a statement.
81 ADDRESSOF is a constraint expression used to represent &x, whether
82 it appears on the LHS or the RHS of a statement.
84 Each pointer variable in the program is assigned an integer id, and
85 each field of a structure variable is assigned an integer id as well.
87 Structure variables are linked to their list of fields through a "next
88 field" in each variable that points to the next field in offset
90 Each variable for a structure field has
92 1. "size", that tells the size in bits of that field.
93 2. "fullsize, that tells the size in bits of the entire structure.
94 3. "offset", that tells the offset in bits from the beginning of the
95 structure to this field.
107 foo.a -> id 1, size 32, offset 0, fullsize 64, next foo.b
108 foo.b -> id 2, size 32, offset 32, fullsize 64, next NULL
109 bar -> id 3, size 32, offset 0, fullsize 32, next NULL
112 In order to solve the system of set constraints, the following is
115 1. Each constraint variable x has a solution set associated with it,
118 2. Constraints are separated into direct, copy, and complex.
119 Direct constraints are ADDRESSOF constraints that require no extra
120 processing, such as P = &Q
121 Copy constraints are those of the form P = Q.
122 Complex constraints are all the constraints involving dereferences
123 and offsets (including offsetted copies).
125 3. All direct constraints of the form P = &Q are processed, such
126 that Q is added to Sol(P)
128 4. All complex constraints for a given constraint variable are stored in a
129 linked list attached to that variable's node.
131 5. A directed graph is built out of the copy constraints. Each
132 constraint variable is a node in the graph, and an edge from
133 Q to P is added for each copy constraint of the form P = Q
135 6. The graph is then walked, and solution sets are
136 propagated along the copy edges, such that an edge from Q to P
137 causes Sol(P) <- Sol(P) union Sol(Q).
139 7. As we visit each node, all complex constraints associated with
140 that node are processed by adding appropriate copy edges to the graph, or the
141 appropriate variables to the solution set.
143 8. The process of walking the graph is iterated until no solution
146 Prior to walking the graph in steps 6 and 7, We perform static
147 cycle elimination on the constraint graph, as well
148 as off-line variable substitution.
150 TODO: Adding offsets to pointer-to-structures can be handled (IE not punted
151 on and turned into anything), but isn't. You can just see what offset
152 inside the pointed-to struct it's going to access.
154 TODO: Constant bounded arrays can be handled as if they were structs of the
155 same number of elements.
157 TODO: Modeling heap and incoming pointers becomes much better if we
158 add fields to them as we discover them, which we could do.
160 TODO: We could handle unions, but to be honest, it's probably not
161 worth the pain or slowdown. */
163 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map
)))
164 htab_t heapvar_for_stmt
;
166 static bool use_field_sensitive
= true;
167 static int in_ipa_mode
= 0;
169 /* Used for predecessor bitmaps. */
170 static bitmap_obstack predbitmap_obstack
;
172 /* Used for points-to sets. */
173 static bitmap_obstack pta_obstack
;
175 /* Used for oldsolution members of variables. */
176 static bitmap_obstack oldpta_obstack
;
178 /* Used for per-solver-iteration bitmaps. */
179 static bitmap_obstack iteration_obstack
;
181 static unsigned int create_variable_info_for (tree
, const char *);
182 typedef struct constraint_graph
*constraint_graph_t
;
183 static void unify_nodes (constraint_graph_t
, unsigned int, unsigned int, bool);
186 typedef struct constraint
*constraint_t
;
188 DEF_VEC_P(constraint_t
);
189 DEF_VEC_ALLOC_P(constraint_t
,heap
);
191 #define EXECUTE_IF_IN_NONNULL_BITMAP(a, b, c, d) \
193 EXECUTE_IF_SET_IN_BITMAP (a, b, c, d)
195 static struct constraint_stats
197 unsigned int total_vars
;
198 unsigned int nonpointer_vars
;
199 unsigned int unified_vars_static
;
200 unsigned int unified_vars_dynamic
;
201 unsigned int iterations
;
202 unsigned int num_edges
;
203 unsigned int num_implicit_edges
;
204 unsigned int points_to_sets_created
;
209 /* ID of this variable */
212 /* True if this is a variable created by the constraint analysis, such as
213 heap variables and constraints we had to break up. */
214 unsigned int is_artificial_var
:1;
216 /* True if this is a special variable whose solution set should not be
218 unsigned int is_special_var
:1;
220 /* True for variables whose size is not known or variable. */
221 unsigned int is_unknown_size_var
:1;
223 /* True for (sub-)fields that represent a whole variable. */
224 unsigned int is_full_var
: 1;
226 /* True if this is a heap variable. */
227 unsigned int is_heap_var
:1;
229 /* True if this field may contain pointers. */
230 unsigned int may_have_pointers
: 1;
232 /* A link to the variable for the next field in this structure. */
233 struct variable_info
*next
;
235 /* Offset of this variable, in bits, from the base variable */
236 unsigned HOST_WIDE_INT offset
;
238 /* Size of the variable, in bits. */
239 unsigned HOST_WIDE_INT size
;
241 /* Full size of the base variable, in bits. */
242 unsigned HOST_WIDE_INT fullsize
;
244 /* Name of this variable */
247 /* Tree that this variable is associated with. */
250 /* Points-to set for this variable. */
253 /* Old points-to set for this variable. */
256 typedef struct variable_info
*varinfo_t
;
258 static varinfo_t
first_vi_for_offset (varinfo_t
, unsigned HOST_WIDE_INT
);
259 static varinfo_t
first_or_preceding_vi_for_offset (varinfo_t
,
260 unsigned HOST_WIDE_INT
);
261 static varinfo_t
lookup_vi_for_tree (tree
);
263 /* Pool of variable info structures. */
264 static alloc_pool variable_info_pool
;
266 DEF_VEC_P(varinfo_t
);
268 DEF_VEC_ALLOC_P(varinfo_t
, heap
);
270 /* Table of variable info structures for constraint variables.
271 Indexed directly by variable info id. */
272 static VEC(varinfo_t
,heap
) *varmap
;
274 /* Return the varmap element N */
276 static inline varinfo_t
277 get_varinfo (unsigned int n
)
279 return VEC_index (varinfo_t
, varmap
, n
);
282 /* Static IDs for the special variables. */
283 enum { nothing_id
= 0, anything_id
= 1, readonly_id
= 2,
284 escaped_id
= 3, nonlocal_id
= 4, callused_id
= 5,
285 storedanything_id
= 6, integer_id
= 7 };
287 /* Variable that represents the unknown pointer. */
288 static varinfo_t var_anything
;
289 static tree anything_tree
;
291 /* Variable that represents the NULL pointer. */
292 static varinfo_t var_nothing
;
293 static tree nothing_tree
;
295 /* Variable that represents read only memory. */
296 static varinfo_t var_readonly
;
297 static tree readonly_tree
;
299 /* Variable that represents escaped memory. */
300 static varinfo_t var_escaped
;
301 static tree escaped_tree
;
303 /* Variable that represents nonlocal memory. */
304 static varinfo_t var_nonlocal
;
305 static tree nonlocal_tree
;
307 /* Variable that represents call-used memory. */
308 static varinfo_t var_callused
;
309 static tree callused_tree
;
311 /* Variable that represents variables that are stored to anything. */
312 static varinfo_t var_storedanything
;
313 static tree storedanything_tree
;
315 /* Variable that represents integers. This is used for when people do things
317 static varinfo_t var_integer
;
318 static tree integer_tree
;
320 /* Lookup a heap var for FROM, and return it if we find one. */
323 heapvar_lookup (tree from
)
325 struct tree_map
*h
, in
;
328 h
= (struct tree_map
*) htab_find_with_hash (heapvar_for_stmt
, &in
,
329 htab_hash_pointer (from
));
335 /* Insert a mapping FROM->TO in the heap var for statement
339 heapvar_insert (tree from
, tree to
)
344 h
= GGC_NEW (struct tree_map
);
345 h
->hash
= htab_hash_pointer (from
);
348 loc
= htab_find_slot_with_hash (heapvar_for_stmt
, h
, h
->hash
, INSERT
);
349 *(struct tree_map
**) loc
= h
;
352 /* Return a new variable info structure consisting for a variable
353 named NAME, and using constraint graph node NODE. */
356 new_var_info (tree t
, unsigned int id
, const char *name
)
358 varinfo_t ret
= (varinfo_t
) pool_alloc (variable_info_pool
);
363 ret
->is_artificial_var
= false;
364 ret
->is_heap_var
= false;
365 ret
->is_special_var
= false;
366 ret
->is_unknown_size_var
= false;
367 ret
->is_full_var
= false;
368 ret
->may_have_pointers
= true;
369 ret
->solution
= BITMAP_ALLOC (&pta_obstack
);
370 ret
->oldsolution
= BITMAP_ALLOC (&oldpta_obstack
);
375 typedef enum {SCALAR
, DEREF
, ADDRESSOF
} constraint_expr_type
;
377 /* An expression that appears in a constraint. */
379 struct constraint_expr
381 /* Constraint type. */
382 constraint_expr_type type
;
384 /* Variable we are referring to in the constraint. */
387 /* Offset, in bits, of this constraint from the beginning of
388 variables it ends up referring to.
390 IOW, in a deref constraint, we would deref, get the result set,
391 then add OFFSET to each member. */
392 HOST_WIDE_INT offset
;
395 /* Use 0x8000... as special unknown offset. */
396 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
398 typedef struct constraint_expr ce_s
;
400 DEF_VEC_ALLOC_O(ce_s
, heap
);
401 static void get_constraint_for_1 (tree
, VEC(ce_s
, heap
) **, bool);
402 static void get_constraint_for (tree
, VEC(ce_s
, heap
) **);
403 static void do_deref (VEC (ce_s
, heap
) **);
405 /* Our set constraints are made up of two constraint expressions, one
408 As described in the introduction, our set constraints each represent an
409 operation between set valued variables.
413 struct constraint_expr lhs
;
414 struct constraint_expr rhs
;
417 /* List of constraints that we use to build the constraint graph from. */
419 static VEC(constraint_t
,heap
) *constraints
;
420 static alloc_pool constraint_pool
;
424 DEF_VEC_ALLOC_I(int, heap
);
426 /* The constraint graph is represented as an array of bitmaps
427 containing successor nodes. */
429 struct constraint_graph
431 /* Size of this graph, which may be different than the number of
432 nodes in the variable map. */
435 /* Explicit successors of each node. */
438 /* Implicit predecessors of each node (Used for variable
440 bitmap
*implicit_preds
;
442 /* Explicit predecessors of each node (Used for variable substitution). */
445 /* Indirect cycle representatives, or -1 if the node has no indirect
447 int *indirect_cycles
;
449 /* Representative node for a node. rep[a] == a unless the node has
453 /* Equivalence class representative for a label. This is used for
454 variable substitution. */
457 /* Pointer equivalence label for a node. All nodes with the same
458 pointer equivalence label can be unified together at some point
459 (either during constraint optimization or after the constraint
463 /* Pointer equivalence representative for a label. This is used to
464 handle nodes that are pointer equivalent but not location
465 equivalent. We can unite these once the addressof constraints
466 are transformed into initial points-to sets. */
469 /* Pointer equivalence label for each node, used during variable
471 unsigned int *pointer_label
;
473 /* Location equivalence label for each node, used during location
474 equivalence finding. */
475 unsigned int *loc_label
;
477 /* Pointed-by set for each node, used during location equivalence
478 finding. This is pointed-by rather than pointed-to, because it
479 is constructed using the predecessor graph. */
482 /* Points to sets for pointer equivalence. This is *not* the actual
483 points-to sets for nodes. */
486 /* Bitmap of nodes where the bit is set if the node is a direct
487 node. Used for variable substitution. */
488 sbitmap direct_nodes
;
490 /* Bitmap of nodes where the bit is set if the node is address
491 taken. Used for variable substitution. */
492 bitmap address_taken
;
494 /* Vector of complex constraints for each graph node. Complex
495 constraints are those involving dereferences or offsets that are
497 VEC(constraint_t
,heap
) **complex;
500 static constraint_graph_t graph
;
502 /* During variable substitution and the offline version of indirect
503 cycle finding, we create nodes to represent dereferences and
504 address taken constraints. These represent where these start and
506 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
507 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
509 /* Return the representative node for NODE, if NODE has been unioned
511 This function performs path compression along the way to finding
512 the representative. */
515 find (unsigned int node
)
517 gcc_assert (node
< graph
->size
);
518 if (graph
->rep
[node
] != node
)
519 return graph
->rep
[node
] = find (graph
->rep
[node
]);
523 /* Union the TO and FROM nodes to the TO nodes.
524 Note that at some point in the future, we may want to do
525 union-by-rank, in which case we are going to have to return the
526 node we unified to. */
529 unite (unsigned int to
, unsigned int from
)
531 gcc_assert (to
< graph
->size
&& from
< graph
->size
);
532 if (to
!= from
&& graph
->rep
[from
] != to
)
534 graph
->rep
[from
] = to
;
540 /* Create a new constraint consisting of LHS and RHS expressions. */
543 new_constraint (const struct constraint_expr lhs
,
544 const struct constraint_expr rhs
)
546 constraint_t ret
= (constraint_t
) pool_alloc (constraint_pool
);
552 /* Print out constraint C to FILE. */
555 dump_constraint (FILE *file
, constraint_t c
)
557 if (c
->lhs
.type
== ADDRESSOF
)
559 else if (c
->lhs
.type
== DEREF
)
561 fprintf (file
, "%s", get_varinfo (c
->lhs
.var
)->name
);
562 if (c
->lhs
.offset
== UNKNOWN_OFFSET
)
563 fprintf (file
, " + UNKNOWN");
564 else if (c
->lhs
.offset
!= 0)
565 fprintf (file
, " + " HOST_WIDE_INT_PRINT_DEC
, c
->lhs
.offset
);
566 fprintf (file
, " = ");
567 if (c
->rhs
.type
== ADDRESSOF
)
569 else if (c
->rhs
.type
== DEREF
)
571 fprintf (file
, "%s", get_varinfo (c
->rhs
.var
)->name
);
572 if (c
->rhs
.offset
== UNKNOWN_OFFSET
)
573 fprintf (file
, " + UNKNOWN");
574 else if (c
->rhs
.offset
!= 0)
575 fprintf (file
, " + " HOST_WIDE_INT_PRINT_DEC
, c
->rhs
.offset
);
576 fprintf (file
, "\n");
580 void debug_constraint (constraint_t
);
581 void debug_constraints (void);
582 void debug_constraint_graph (void);
583 void debug_solution_for_var (unsigned int);
584 void debug_sa_points_to_info (void);
586 /* Print out constraint C to stderr. */
589 debug_constraint (constraint_t c
)
591 dump_constraint (stderr
, c
);
594 /* Print out all constraints to FILE */
597 dump_constraints (FILE *file
)
601 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
602 dump_constraint (file
, c
);
605 /* Print out all constraints to stderr. */
608 debug_constraints (void)
610 dump_constraints (stderr
);
613 /* Print out to FILE the edge in the constraint graph that is created by
614 constraint c. The edge may have a label, depending on the type of
615 constraint that it represents. If complex1, e.g: a = *b, then the label
616 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
617 complex with an offset, e.g: a = b + 8, then the label is "+".
618 Otherwise the edge has no label. */
621 dump_constraint_edge (FILE *file
, constraint_t c
)
623 if (c
->rhs
.type
!= ADDRESSOF
)
625 const char *src
= get_varinfo (c
->rhs
.var
)->name
;
626 const char *dst
= get_varinfo (c
->lhs
.var
)->name
;
627 fprintf (file
, " \"%s\" -> \"%s\" ", src
, dst
);
628 /* Due to preprocessing of constraints, instructions like *a = *b are
629 illegal; thus, we do not have to handle such cases. */
630 if (c
->lhs
.type
== DEREF
)
631 fprintf (file
, " [ label=\"*=\" ] ;\n");
632 else if (c
->rhs
.type
== DEREF
)
633 fprintf (file
, " [ label=\"=*\" ] ;\n");
636 /* We must check the case where the constraint is an offset.
637 In this case, it is treated as a complex constraint. */
638 if (c
->rhs
.offset
!= c
->lhs
.offset
)
639 fprintf (file
, " [ label=\"+\" ] ;\n");
641 fprintf (file
, " ;\n");
646 /* Print the constraint graph in dot format. */
649 dump_constraint_graph (FILE *file
)
651 unsigned int i
=0, size
;
654 /* Only print the graph if it has already been initialized: */
658 /* Print the constraints used to produce the constraint graph. The
659 constraints will be printed as comments in the dot file: */
660 fprintf (file
, "\n\n/* Constraints used in the constraint graph:\n");
661 dump_constraints (file
);
662 fprintf (file
, "*/\n");
664 /* Prints the header of the dot file: */
665 fprintf (file
, "\n\n// The constraint graph in dot format:\n");
666 fprintf (file
, "strict digraph {\n");
667 fprintf (file
, " node [\n shape = box\n ]\n");
668 fprintf (file
, " edge [\n fontsize = \"12\"\n ]\n");
669 fprintf (file
, "\n // List of nodes in the constraint graph:\n");
671 /* The next lines print the nodes in the graph. In order to get the
672 number of nodes in the graph, we must choose the minimum between the
673 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
674 yet been initialized, then graph->size == 0, otherwise we must only
675 read nodes that have an entry in VEC (varinfo_t, varmap). */
676 size
= VEC_length (varinfo_t
, varmap
);
677 size
= size
< graph
->size
? size
: graph
->size
;
678 for (i
= 0; i
< size
; i
++)
680 const char *name
= get_varinfo (graph
->rep
[i
])->name
;
681 fprintf (file
, " \"%s\" ;\n", name
);
684 /* Go over the list of constraints printing the edges in the constraint
686 fprintf (file
, "\n // The constraint edges:\n");
687 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
689 dump_constraint_edge (file
, c
);
691 /* Prints the tail of the dot file. By now, only the closing bracket. */
692 fprintf (file
, "}\n\n\n");
695 /* Print out the constraint graph to stderr. */
698 debug_constraint_graph (void)
700 dump_constraint_graph (stderr
);
705 The solver is a simple worklist solver, that works on the following
708 sbitmap changed_nodes = all zeroes;
710 For each node that is not already collapsed:
712 set bit in changed nodes
714 while (changed_count > 0)
716 compute topological ordering for constraint graph
718 find and collapse cycles in the constraint graph (updating
719 changed if necessary)
721 for each node (n) in the graph in topological order:
724 Process each complex constraint associated with the node,
725 updating changed if necessary.
727 For each outgoing edge from n, propagate the solution from n to
728 the destination of the edge, updating changed as necessary.
732 /* Return true if two constraint expressions A and B are equal. */
735 constraint_expr_equal (struct constraint_expr a
, struct constraint_expr b
)
737 return a
.type
== b
.type
&& a
.var
== b
.var
&& a
.offset
== b
.offset
;
740 /* Return true if constraint expression A is less than constraint expression
741 B. This is just arbitrary, but consistent, in order to give them an
745 constraint_expr_less (struct constraint_expr a
, struct constraint_expr b
)
747 if (a
.type
== b
.type
)
750 return a
.offset
< b
.offset
;
752 return a
.var
< b
.var
;
755 return a
.type
< b
.type
;
758 /* Return true if constraint A is less than constraint B. This is just
759 arbitrary, but consistent, in order to give them an ordering. */
762 constraint_less (const constraint_t a
, const constraint_t b
)
764 if (constraint_expr_less (a
->lhs
, b
->lhs
))
766 else if (constraint_expr_less (b
->lhs
, a
->lhs
))
769 return constraint_expr_less (a
->rhs
, b
->rhs
);
772 /* Return true if two constraints A and B are equal. */
775 constraint_equal (struct constraint a
, struct constraint b
)
777 return constraint_expr_equal (a
.lhs
, b
.lhs
)
778 && constraint_expr_equal (a
.rhs
, b
.rhs
);
782 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
785 constraint_vec_find (VEC(constraint_t
,heap
) *vec
,
786 struct constraint lookfor
)
794 place
= VEC_lower_bound (constraint_t
, vec
, &lookfor
, constraint_less
);
795 if (place
>= VEC_length (constraint_t
, vec
))
797 found
= VEC_index (constraint_t
, vec
, place
);
798 if (!constraint_equal (*found
, lookfor
))
803 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
806 constraint_set_union (VEC(constraint_t
,heap
) **to
,
807 VEC(constraint_t
,heap
) **from
)
812 for (i
= 0; VEC_iterate (constraint_t
, *from
, i
, c
); i
++)
814 if (constraint_vec_find (*to
, *c
) == NULL
)
816 unsigned int place
= VEC_lower_bound (constraint_t
, *to
, c
,
818 VEC_safe_insert (constraint_t
, heap
, *to
, place
, c
);
823 /* Expands the solution in SET to all sub-fields of variables included.
824 Union the expanded result into RESULT. */
827 solution_set_expand (bitmap result
, bitmap set
)
833 /* In a first pass record all variables we need to add all
834 sub-fields off. This avoids quadratic behavior. */
835 EXECUTE_IF_SET_IN_BITMAP (set
, 0, j
, bi
)
837 varinfo_t v
= get_varinfo (j
);
838 if (v
->is_artificial_var
841 v
= lookup_vi_for_tree (v
->decl
);
843 vars
= BITMAP_ALLOC (NULL
);
844 bitmap_set_bit (vars
, v
->id
);
847 /* In the second pass now do the addition to the solution and
848 to speed up solving add it to the delta as well. */
851 EXECUTE_IF_SET_IN_BITMAP (vars
, 0, j
, bi
)
853 varinfo_t v
= get_varinfo (j
);
854 for (; v
!= NULL
; v
= v
->next
)
855 bitmap_set_bit (result
, v
->id
);
861 /* Take a solution set SET, add OFFSET to each member of the set, and
862 overwrite SET with the result when done. */
865 solution_set_add (bitmap set
, HOST_WIDE_INT offset
)
867 bitmap result
= BITMAP_ALLOC (&iteration_obstack
);
871 /* If the offset is unknown we have to expand the solution to
873 if (offset
== UNKNOWN_OFFSET
)
875 solution_set_expand (set
, set
);
879 EXECUTE_IF_SET_IN_BITMAP (set
, 0, i
, bi
)
881 varinfo_t vi
= get_varinfo (i
);
883 /* If this is a variable with just one field just set its bit
885 if (vi
->is_artificial_var
886 || vi
->is_unknown_size_var
888 bitmap_set_bit (result
, i
);
891 unsigned HOST_WIDE_INT fieldoffset
= vi
->offset
+ offset
;
893 /* If the offset makes the pointer point to before the
894 variable use offset zero for the field lookup. */
896 && fieldoffset
> vi
->offset
)
900 vi
= first_or_preceding_vi_for_offset (vi
, fieldoffset
);
902 bitmap_set_bit (result
, vi
->id
);
903 /* If the result is not exactly at fieldoffset include the next
904 field as well. See get_constraint_for_ptr_offset for more
906 if (vi
->offset
!= fieldoffset
908 bitmap_set_bit (result
, vi
->next
->id
);
912 bitmap_copy (set
, result
);
913 BITMAP_FREE (result
);
916 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
920 set_union_with_increment (bitmap to
, bitmap from
, HOST_WIDE_INT inc
)
923 return bitmap_ior_into (to
, from
);
929 tmp
= BITMAP_ALLOC (&iteration_obstack
);
930 bitmap_copy (tmp
, from
);
931 solution_set_add (tmp
, inc
);
932 res
= bitmap_ior_into (to
, tmp
);
938 /* Insert constraint C into the list of complex constraints for graph
942 insert_into_complex (constraint_graph_t graph
,
943 unsigned int var
, constraint_t c
)
945 VEC (constraint_t
, heap
) *complex = graph
->complex[var
];
946 unsigned int place
= VEC_lower_bound (constraint_t
, complex, c
,
949 /* Only insert constraints that do not already exist. */
950 if (place
>= VEC_length (constraint_t
, complex)
951 || !constraint_equal (*c
, *VEC_index (constraint_t
, complex, place
)))
952 VEC_safe_insert (constraint_t
, heap
, graph
->complex[var
], place
, c
);
956 /* Condense two variable nodes into a single variable node, by moving
957 all associated info from SRC to TO. */
960 merge_node_constraints (constraint_graph_t graph
, unsigned int to
,
966 gcc_assert (find (from
) == to
);
968 /* Move all complex constraints from src node into to node */
969 for (i
= 0; VEC_iterate (constraint_t
, graph
->complex[from
], i
, c
); i
++)
971 /* In complex constraints for node src, we may have either
972 a = *src, and *src = a, or an offseted constraint which are
973 always added to the rhs node's constraints. */
975 if (c
->rhs
.type
== DEREF
)
977 else if (c
->lhs
.type
== DEREF
)
982 constraint_set_union (&graph
->complex[to
], &graph
->complex[from
]);
983 VEC_free (constraint_t
, heap
, graph
->complex[from
]);
984 graph
->complex[from
] = NULL
;
988 /* Remove edges involving NODE from GRAPH. */
991 clear_edges_for_node (constraint_graph_t graph
, unsigned int node
)
993 if (graph
->succs
[node
])
994 BITMAP_FREE (graph
->succs
[node
]);
997 /* Merge GRAPH nodes FROM and TO into node TO. */
1000 merge_graph_nodes (constraint_graph_t graph
, unsigned int to
,
1003 if (graph
->indirect_cycles
[from
] != -1)
1005 /* If we have indirect cycles with the from node, and we have
1006 none on the to node, the to node has indirect cycles from the
1007 from node now that they are unified.
1008 If indirect cycles exist on both, unify the nodes that they
1009 are in a cycle with, since we know they are in a cycle with
1011 if (graph
->indirect_cycles
[to
] == -1)
1012 graph
->indirect_cycles
[to
] = graph
->indirect_cycles
[from
];
1015 /* Merge all the successor edges. */
1016 if (graph
->succs
[from
])
1018 if (!graph
->succs
[to
])
1019 graph
->succs
[to
] = BITMAP_ALLOC (&pta_obstack
);
1020 bitmap_ior_into (graph
->succs
[to
],
1021 graph
->succs
[from
]);
1024 clear_edges_for_node (graph
, from
);
1028 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1029 it doesn't exist in the graph already. */
1032 add_implicit_graph_edge (constraint_graph_t graph
, unsigned int to
,
1038 if (!graph
->implicit_preds
[to
])
1039 graph
->implicit_preds
[to
] = BITMAP_ALLOC (&predbitmap_obstack
);
1041 if (bitmap_set_bit (graph
->implicit_preds
[to
], from
))
1042 stats
.num_implicit_edges
++;
1045 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1046 it doesn't exist in the graph already.
1047 Return false if the edge already existed, true otherwise. */
1050 add_pred_graph_edge (constraint_graph_t graph
, unsigned int to
,
1053 if (!graph
->preds
[to
])
1054 graph
->preds
[to
] = BITMAP_ALLOC (&predbitmap_obstack
);
1055 bitmap_set_bit (graph
->preds
[to
], from
);
1058 /* Add a graph edge to GRAPH, going from FROM to TO if
1059 it doesn't exist in the graph already.
1060 Return false if the edge already existed, true otherwise. */
1063 add_graph_edge (constraint_graph_t graph
, unsigned int to
,
1074 if (!graph
->succs
[from
])
1075 graph
->succs
[from
] = BITMAP_ALLOC (&pta_obstack
);
1076 if (bitmap_set_bit (graph
->succs
[from
], to
))
1079 if (to
< FIRST_REF_NODE
&& from
< FIRST_REF_NODE
)
1087 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1090 valid_graph_edge (constraint_graph_t graph
, unsigned int src
,
1093 return (graph
->succs
[dest
]
1094 && bitmap_bit_p (graph
->succs
[dest
], src
));
1097 /* Initialize the constraint graph structure to contain SIZE nodes. */
1100 init_graph (unsigned int size
)
1104 graph
= XCNEW (struct constraint_graph
);
1106 graph
->succs
= XCNEWVEC (bitmap
, graph
->size
);
1107 graph
->indirect_cycles
= XNEWVEC (int, graph
->size
);
1108 graph
->rep
= XNEWVEC (unsigned int, graph
->size
);
1109 graph
->complex = XCNEWVEC (VEC(constraint_t
, heap
) *, size
);
1110 graph
->pe
= XCNEWVEC (unsigned int, graph
->size
);
1111 graph
->pe_rep
= XNEWVEC (int, graph
->size
);
1113 for (j
= 0; j
< graph
->size
; j
++)
1116 graph
->pe_rep
[j
] = -1;
1117 graph
->indirect_cycles
[j
] = -1;
1121 /* Build the constraint graph, adding only predecessor edges right now. */
1124 build_pred_graph (void)
1130 graph
->implicit_preds
= XCNEWVEC (bitmap
, graph
->size
);
1131 graph
->preds
= XCNEWVEC (bitmap
, graph
->size
);
1132 graph
->pointer_label
= XCNEWVEC (unsigned int, graph
->size
);
1133 graph
->loc_label
= XCNEWVEC (unsigned int, graph
->size
);
1134 graph
->pointed_by
= XCNEWVEC (bitmap
, graph
->size
);
1135 graph
->points_to
= XCNEWVEC (bitmap
, graph
->size
);
1136 graph
->eq_rep
= XNEWVEC (int, graph
->size
);
1137 graph
->direct_nodes
= sbitmap_alloc (graph
->size
);
1138 graph
->address_taken
= BITMAP_ALLOC (&predbitmap_obstack
);
1139 sbitmap_zero (graph
->direct_nodes
);
1141 for (j
= 0; j
< FIRST_REF_NODE
; j
++)
1143 if (!get_varinfo (j
)->is_special_var
)
1144 SET_BIT (graph
->direct_nodes
, j
);
1147 for (j
= 0; j
< graph
->size
; j
++)
1148 graph
->eq_rep
[j
] = -1;
1150 for (j
= 0; j
< VEC_length (varinfo_t
, varmap
); j
++)
1151 graph
->indirect_cycles
[j
] = -1;
1153 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
1155 struct constraint_expr lhs
= c
->lhs
;
1156 struct constraint_expr rhs
= c
->rhs
;
1157 unsigned int lhsvar
= lhs
.var
;
1158 unsigned int rhsvar
= rhs
.var
;
1160 if (lhs
.type
== DEREF
)
1163 if (rhs
.offset
== 0 && lhs
.offset
== 0 && rhs
.type
== SCALAR
)
1164 add_pred_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1166 else if (rhs
.type
== DEREF
)
1169 if (rhs
.offset
== 0 && lhs
.offset
== 0 && lhs
.type
== SCALAR
)
1170 add_pred_graph_edge (graph
, lhsvar
, FIRST_REF_NODE
+ rhsvar
);
1172 RESET_BIT (graph
->direct_nodes
, lhsvar
);
1174 else if (rhs
.type
== ADDRESSOF
)
1179 if (graph
->points_to
[lhsvar
] == NULL
)
1180 graph
->points_to
[lhsvar
] = BITMAP_ALLOC (&predbitmap_obstack
);
1181 bitmap_set_bit (graph
->points_to
[lhsvar
], rhsvar
);
1183 if (graph
->pointed_by
[rhsvar
] == NULL
)
1184 graph
->pointed_by
[rhsvar
] = BITMAP_ALLOC (&predbitmap_obstack
);
1185 bitmap_set_bit (graph
->pointed_by
[rhsvar
], lhsvar
);
1187 /* Implicitly, *x = y */
1188 add_implicit_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1190 /* All related variables are no longer direct nodes. */
1191 RESET_BIT (graph
->direct_nodes
, rhsvar
);
1192 v
= get_varinfo (rhsvar
);
1193 if (!v
->is_full_var
)
1195 v
= lookup_vi_for_tree (v
->decl
);
1198 RESET_BIT (graph
->direct_nodes
, v
->id
);
1203 bitmap_set_bit (graph
->address_taken
, rhsvar
);
1205 else if (lhsvar
> anything_id
1206 && lhsvar
!= rhsvar
&& lhs
.offset
== 0 && rhs
.offset
== 0)
1209 add_pred_graph_edge (graph
, lhsvar
, rhsvar
);
1210 /* Implicitly, *x = *y */
1211 add_implicit_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
,
1212 FIRST_REF_NODE
+ rhsvar
);
1214 else if (lhs
.offset
!= 0 || rhs
.offset
!= 0)
1216 if (rhs
.offset
!= 0)
1217 RESET_BIT (graph
->direct_nodes
, lhs
.var
);
1218 else if (lhs
.offset
!= 0)
1219 RESET_BIT (graph
->direct_nodes
, rhs
.var
);
1224 /* Build the constraint graph, adding successor edges. */
1227 build_succ_graph (void)
1232 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
1234 struct constraint_expr lhs
;
1235 struct constraint_expr rhs
;
1236 unsigned int lhsvar
;
1237 unsigned int rhsvar
;
1244 lhsvar
= find (lhs
.var
);
1245 rhsvar
= find (rhs
.var
);
1247 if (lhs
.type
== DEREF
)
1249 if (rhs
.offset
== 0 && lhs
.offset
== 0 && rhs
.type
== SCALAR
)
1250 add_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1252 else if (rhs
.type
== DEREF
)
1254 if (rhs
.offset
== 0 && lhs
.offset
== 0 && lhs
.type
== SCALAR
)
1255 add_graph_edge (graph
, lhsvar
, FIRST_REF_NODE
+ rhsvar
);
1257 else if (rhs
.type
== ADDRESSOF
)
1260 gcc_assert (find (rhs
.var
) == rhs
.var
);
1261 bitmap_set_bit (get_varinfo (lhsvar
)->solution
, rhsvar
);
1263 else if (lhsvar
> anything_id
1264 && lhsvar
!= rhsvar
&& lhs
.offset
== 0 && rhs
.offset
== 0)
1266 add_graph_edge (graph
, lhsvar
, rhsvar
);
1270 /* Add edges from STOREDANYTHING to all non-direct nodes. */
1271 t
= find (storedanything_id
);
1272 for (i
= integer_id
+ 1; i
< FIRST_REF_NODE
; ++i
)
1274 if (!TEST_BIT (graph
->direct_nodes
, i
))
1275 add_graph_edge (graph
, find (i
), t
);
1280 /* Changed variables on the last iteration. */
1281 static unsigned int changed_count
;
1282 static sbitmap changed
;
1284 DEF_VEC_I(unsigned);
1285 DEF_VEC_ALLOC_I(unsigned,heap
);
1288 /* Strongly Connected Component visitation info. */
1295 unsigned int *node_mapping
;
1297 VEC(unsigned,heap
) *scc_stack
;
1301 /* Recursive routine to find strongly connected components in GRAPH.
1302 SI is the SCC info to store the information in, and N is the id of current
1303 graph node we are processing.
1305 This is Tarjan's strongly connected component finding algorithm, as
1306 modified by Nuutila to keep only non-root nodes on the stack.
1307 The algorithm can be found in "On finding the strongly connected
1308 connected components in a directed graph" by Esko Nuutila and Eljas
1309 Soisalon-Soininen, in Information Processing Letters volume 49,
1310 number 1, pages 9-14. */
1313 scc_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
1317 unsigned int my_dfs
;
1319 SET_BIT (si
->visited
, n
);
1320 si
->dfs
[n
] = si
->current_index
++;
1321 my_dfs
= si
->dfs
[n
];
1323 /* Visit all the successors. */
1324 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->succs
[n
], 0, i
, bi
)
1328 if (i
> LAST_REF_NODE
)
1332 if (TEST_BIT (si
->deleted
, w
))
1335 if (!TEST_BIT (si
->visited
, w
))
1336 scc_visit (graph
, si
, w
);
1338 unsigned int t
= find (w
);
1339 unsigned int nnode
= find (n
);
1340 gcc_assert (nnode
== n
);
1342 if (si
->dfs
[t
] < si
->dfs
[nnode
])
1343 si
->dfs
[n
] = si
->dfs
[t
];
1347 /* See if any components have been identified. */
1348 if (si
->dfs
[n
] == my_dfs
)
1350 if (VEC_length (unsigned, si
->scc_stack
) > 0
1351 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
1353 bitmap scc
= BITMAP_ALLOC (NULL
);
1354 bool have_ref_node
= n
>= FIRST_REF_NODE
;
1355 unsigned int lowest_node
;
1358 bitmap_set_bit (scc
, n
);
1360 while (VEC_length (unsigned, si
->scc_stack
) != 0
1361 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
1363 unsigned int w
= VEC_pop (unsigned, si
->scc_stack
);
1365 bitmap_set_bit (scc
, w
);
1366 if (w
>= FIRST_REF_NODE
)
1367 have_ref_node
= true;
1370 lowest_node
= bitmap_first_set_bit (scc
);
1371 gcc_assert (lowest_node
< FIRST_REF_NODE
);
1373 /* Collapse the SCC nodes into a single node, and mark the
1375 EXECUTE_IF_SET_IN_BITMAP (scc
, 0, i
, bi
)
1377 if (i
< FIRST_REF_NODE
)
1379 if (unite (lowest_node
, i
))
1380 unify_nodes (graph
, lowest_node
, i
, false);
1384 unite (lowest_node
, i
);
1385 graph
->indirect_cycles
[i
- FIRST_REF_NODE
] = lowest_node
;
1389 SET_BIT (si
->deleted
, n
);
1392 VEC_safe_push (unsigned, heap
, si
->scc_stack
, n
);
1395 /* Unify node FROM into node TO, updating the changed count if
1396 necessary when UPDATE_CHANGED is true. */
1399 unify_nodes (constraint_graph_t graph
, unsigned int to
, unsigned int from
,
1400 bool update_changed
)
1403 gcc_assert (to
!= from
&& find (to
) == to
);
1404 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1405 fprintf (dump_file
, "Unifying %s to %s\n",
1406 get_varinfo (from
)->name
,
1407 get_varinfo (to
)->name
);
1410 stats
.unified_vars_dynamic
++;
1412 stats
.unified_vars_static
++;
1414 merge_graph_nodes (graph
, to
, from
);
1415 merge_node_constraints (graph
, to
, from
);
1417 /* Mark TO as changed if FROM was changed. If TO was already marked
1418 as changed, decrease the changed count. */
1420 if (update_changed
&& TEST_BIT (changed
, from
))
1422 RESET_BIT (changed
, from
);
1423 if (!TEST_BIT (changed
, to
))
1424 SET_BIT (changed
, to
);
1427 gcc_assert (changed_count
> 0);
1431 if (get_varinfo (from
)->solution
)
1433 /* If the solution changes because of the merging, we need to mark
1434 the variable as changed. */
1435 if (bitmap_ior_into (get_varinfo (to
)->solution
,
1436 get_varinfo (from
)->solution
))
1438 if (update_changed
&& !TEST_BIT (changed
, to
))
1440 SET_BIT (changed
, to
);
1445 BITMAP_FREE (get_varinfo (from
)->solution
);
1446 BITMAP_FREE (get_varinfo (from
)->oldsolution
);
1448 if (stats
.iterations
> 0)
1450 BITMAP_FREE (get_varinfo (to
)->oldsolution
);
1451 get_varinfo (to
)->oldsolution
= BITMAP_ALLOC (&oldpta_obstack
);
1454 if (valid_graph_edge (graph
, to
, to
))
1456 if (graph
->succs
[to
])
1457 bitmap_clear_bit (graph
->succs
[to
], to
);
1461 /* Information needed to compute the topological ordering of a graph. */
1465 /* sbitmap of visited nodes. */
1467 /* Array that stores the topological order of the graph, *in
1469 VEC(unsigned,heap
) *topo_order
;
1473 /* Initialize and return a topological info structure. */
1475 static struct topo_info
*
1476 init_topo_info (void)
1478 size_t size
= graph
->size
;
1479 struct topo_info
*ti
= XNEW (struct topo_info
);
1480 ti
->visited
= sbitmap_alloc (size
);
1481 sbitmap_zero (ti
->visited
);
1482 ti
->topo_order
= VEC_alloc (unsigned, heap
, 1);
1487 /* Free the topological sort info pointed to by TI. */
1490 free_topo_info (struct topo_info
*ti
)
1492 sbitmap_free (ti
->visited
);
1493 VEC_free (unsigned, heap
, ti
->topo_order
);
1497 /* Visit the graph in topological order, and store the order in the
1498 topo_info structure. */
1501 topo_visit (constraint_graph_t graph
, struct topo_info
*ti
,
1507 SET_BIT (ti
->visited
, n
);
1509 if (graph
->succs
[n
])
1510 EXECUTE_IF_SET_IN_BITMAP (graph
->succs
[n
], 0, j
, bi
)
1512 if (!TEST_BIT (ti
->visited
, j
))
1513 topo_visit (graph
, ti
, j
);
1516 VEC_safe_push (unsigned, heap
, ti
->topo_order
, n
);
1519 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1520 starting solution for y. */
1523 do_sd_constraint (constraint_graph_t graph
, constraint_t c
,
1526 unsigned int lhs
= c
->lhs
.var
;
1528 bitmap sol
= get_varinfo (lhs
)->solution
;
1531 HOST_WIDE_INT roffset
= c
->rhs
.offset
;
1533 /* Our IL does not allow this. */
1534 gcc_assert (c
->lhs
.offset
== 0);
1536 /* If the solution of Y contains anything it is good enough to transfer
1538 if (bitmap_bit_p (delta
, anything_id
))
1540 flag
|= bitmap_set_bit (sol
, anything_id
);
1544 /* If we do not know at with offset the rhs is dereferenced compute
1545 the reachability set of DELTA, conservatively assuming it is
1546 dereferenced at all valid offsets. */
1547 if (roffset
== UNKNOWN_OFFSET
)
1549 solution_set_expand (delta
, delta
);
1550 /* No further offset processing is necessary. */
1554 /* For each variable j in delta (Sol(y)), add
1555 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1556 EXECUTE_IF_SET_IN_BITMAP (delta
, 0, j
, bi
)
1558 varinfo_t v
= get_varinfo (j
);
1559 HOST_WIDE_INT fieldoffset
= v
->offset
+ roffset
;
1563 fieldoffset
= v
->offset
;
1564 else if (roffset
!= 0)
1565 v
= first_vi_for_offset (v
, fieldoffset
);
1566 /* If the access is outside of the variable we can ignore it. */
1574 /* Adding edges from the special vars is pointless.
1575 They don't have sets that can change. */
1576 if (get_varinfo (t
)->is_special_var
)
1577 flag
|= bitmap_ior_into (sol
, get_varinfo (t
)->solution
);
1578 /* Merging the solution from ESCAPED needlessly increases
1579 the set. Use ESCAPED as representative instead. */
1580 else if (v
->id
== escaped_id
)
1581 flag
|= bitmap_set_bit (sol
, escaped_id
);
1582 else if (add_graph_edge (graph
, lhs
, t
))
1583 flag
|= bitmap_ior_into (sol
, get_varinfo (t
)->solution
);
1585 /* If the variable is not exactly at the requested offset
1586 we have to include the next one. */
1587 if (v
->offset
== (unsigned HOST_WIDE_INT
)fieldoffset
1592 fieldoffset
= v
->offset
;
1598 /* If the LHS solution changed, mark the var as changed. */
1601 get_varinfo (lhs
)->solution
= sol
;
1602 if (!TEST_BIT (changed
, lhs
))
1604 SET_BIT (changed
, lhs
);
1610 /* Process a constraint C that represents *(x + off) = y using DELTA
1611 as the starting solution for x. */
1614 do_ds_constraint (constraint_t c
, bitmap delta
)
1616 unsigned int rhs
= c
->rhs
.var
;
1617 bitmap sol
= get_varinfo (rhs
)->solution
;
1620 HOST_WIDE_INT loff
= c
->lhs
.offset
;
1622 /* Our IL does not allow this. */
1623 gcc_assert (c
->rhs
.offset
== 0);
1625 /* If the solution of y contains ANYTHING simply use the ANYTHING
1626 solution. This avoids needlessly increasing the points-to sets. */
1627 if (bitmap_bit_p (sol
, anything_id
))
1628 sol
= get_varinfo (find (anything_id
))->solution
;
1630 /* If the solution for x contains ANYTHING we have to merge the
1631 solution of y into all pointer variables which we do via
1633 if (bitmap_bit_p (delta
, anything_id
))
1635 unsigned t
= find (storedanything_id
);
1636 if (add_graph_edge (graph
, t
, rhs
))
1638 if (bitmap_ior_into (get_varinfo (t
)->solution
, sol
))
1640 if (!TEST_BIT (changed
, t
))
1642 SET_BIT (changed
, t
);
1650 /* If we do not know at with offset the rhs is dereferenced compute
1651 the reachability set of DELTA, conservatively assuming it is
1652 dereferenced at all valid offsets. */
1653 if (loff
== UNKNOWN_OFFSET
)
1655 solution_set_expand (delta
, delta
);
1659 /* For each member j of delta (Sol(x)), add an edge from y to j and
1660 union Sol(y) into Sol(j) */
1661 EXECUTE_IF_SET_IN_BITMAP (delta
, 0, j
, bi
)
1663 varinfo_t v
= get_varinfo (j
);
1665 HOST_WIDE_INT fieldoffset
= v
->offset
+ loff
;
1667 if (v
->is_special_var
)
1671 fieldoffset
= v
->offset
;
1673 v
= first_vi_for_offset (v
, fieldoffset
);
1674 /* If the access is outside of the variable we can ignore it. */
1680 if (v
->may_have_pointers
)
1683 if (add_graph_edge (graph
, t
, rhs
))
1685 if (bitmap_ior_into (get_varinfo (t
)->solution
, sol
))
1688 sol
= get_varinfo (rhs
)->solution
;
1689 if (!TEST_BIT (changed
, t
))
1691 SET_BIT (changed
, t
);
1698 /* If the variable is not exactly at the requested offset
1699 we have to include the next one. */
1700 if (v
->offset
== (unsigned HOST_WIDE_INT
)fieldoffset
1705 fieldoffset
= v
->offset
;
1711 /* Handle a non-simple (simple meaning requires no iteration),
1712 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1715 do_complex_constraint (constraint_graph_t graph
, constraint_t c
, bitmap delta
)
1717 if (c
->lhs
.type
== DEREF
)
1719 if (c
->rhs
.type
== ADDRESSOF
)
1726 do_ds_constraint (c
, delta
);
1729 else if (c
->rhs
.type
== DEREF
)
1732 if (!(get_varinfo (c
->lhs
.var
)->is_special_var
))
1733 do_sd_constraint (graph
, c
, delta
);
1741 gcc_assert (c
->rhs
.type
== SCALAR
&& c
->lhs
.type
== SCALAR
);
1742 solution
= get_varinfo (c
->rhs
.var
)->solution
;
1743 tmp
= get_varinfo (c
->lhs
.var
)->solution
;
1745 flag
= set_union_with_increment (tmp
, solution
, c
->rhs
.offset
);
1749 get_varinfo (c
->lhs
.var
)->solution
= tmp
;
1750 if (!TEST_BIT (changed
, c
->lhs
.var
))
1752 SET_BIT (changed
, c
->lhs
.var
);
1759 /* Initialize and return a new SCC info structure. */
1761 static struct scc_info
*
1762 init_scc_info (size_t size
)
1764 struct scc_info
*si
= XNEW (struct scc_info
);
1767 si
->current_index
= 0;
1768 si
->visited
= sbitmap_alloc (size
);
1769 sbitmap_zero (si
->visited
);
1770 si
->deleted
= sbitmap_alloc (size
);
1771 sbitmap_zero (si
->deleted
);
1772 si
->node_mapping
= XNEWVEC (unsigned int, size
);
1773 si
->dfs
= XCNEWVEC (unsigned int, size
);
1775 for (i
= 0; i
< size
; i
++)
1776 si
->node_mapping
[i
] = i
;
1778 si
->scc_stack
= VEC_alloc (unsigned, heap
, 1);
1782 /* Free an SCC info structure pointed to by SI */
1785 free_scc_info (struct scc_info
*si
)
1787 sbitmap_free (si
->visited
);
1788 sbitmap_free (si
->deleted
);
1789 free (si
->node_mapping
);
1791 VEC_free (unsigned, heap
, si
->scc_stack
);
1796 /* Find indirect cycles in GRAPH that occur, using strongly connected
1797 components, and note them in the indirect cycles map.
1799 This technique comes from Ben Hardekopf and Calvin Lin,
1800 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1801 Lines of Code", submitted to PLDI 2007. */
1804 find_indirect_cycles (constraint_graph_t graph
)
1807 unsigned int size
= graph
->size
;
1808 struct scc_info
*si
= init_scc_info (size
);
1810 for (i
= 0; i
< MIN (LAST_REF_NODE
, size
); i
++ )
1811 if (!TEST_BIT (si
->visited
, i
) && find (i
) == i
)
1812 scc_visit (graph
, si
, i
);
1817 /* Compute a topological ordering for GRAPH, and store the result in the
1818 topo_info structure TI. */
1821 compute_topo_order (constraint_graph_t graph
,
1822 struct topo_info
*ti
)
1825 unsigned int size
= graph
->size
;
1827 for (i
= 0; i
!= size
; ++i
)
1828 if (!TEST_BIT (ti
->visited
, i
) && find (i
) == i
)
1829 topo_visit (graph
, ti
, i
);
1832 /* Structure used to for hash value numbering of pointer equivalence
1835 typedef struct equiv_class_label
1838 unsigned int equivalence_class
;
1840 } *equiv_class_label_t
;
1841 typedef const struct equiv_class_label
*const_equiv_class_label_t
;
1843 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1845 static htab_t pointer_equiv_class_table
;
1847 /* A hashtable for mapping a bitmap of labels->location equivalence
1849 static htab_t location_equiv_class_table
;
1851 /* Hash function for a equiv_class_label_t */
1854 equiv_class_label_hash (const void *p
)
1856 const_equiv_class_label_t
const ecl
= (const_equiv_class_label_t
) p
;
1857 return ecl
->hashcode
;
1860 /* Equality function for two equiv_class_label_t's. */
1863 equiv_class_label_eq (const void *p1
, const void *p2
)
1865 const_equiv_class_label_t
const eql1
= (const_equiv_class_label_t
) p1
;
1866 const_equiv_class_label_t
const eql2
= (const_equiv_class_label_t
) p2
;
1867 return bitmap_equal_p (eql1
->labels
, eql2
->labels
);
1870 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1874 equiv_class_lookup (htab_t table
, bitmap labels
)
1877 struct equiv_class_label ecl
;
1879 ecl
.labels
= labels
;
1880 ecl
.hashcode
= bitmap_hash (labels
);
1882 slot
= htab_find_slot_with_hash (table
, &ecl
,
1883 ecl
.hashcode
, NO_INSERT
);
1887 return ((equiv_class_label_t
) *slot
)->equivalence_class
;
1891 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1895 equiv_class_add (htab_t table
, unsigned int equivalence_class
,
1899 equiv_class_label_t ecl
= XNEW (struct equiv_class_label
);
1901 ecl
->labels
= labels
;
1902 ecl
->equivalence_class
= equivalence_class
;
1903 ecl
->hashcode
= bitmap_hash (labels
);
1905 slot
= htab_find_slot_with_hash (table
, ecl
,
1906 ecl
->hashcode
, INSERT
);
1907 gcc_assert (!*slot
);
1908 *slot
= (void *) ecl
;
1911 /* Perform offline variable substitution.
1913 This is a worst case quadratic time way of identifying variables
1914 that must have equivalent points-to sets, including those caused by
1915 static cycles, and single entry subgraphs, in the constraint graph.
1917 The technique is described in "Exploiting Pointer and Location
1918 Equivalence to Optimize Pointer Analysis. In the 14th International
1919 Static Analysis Symposium (SAS), August 2007." It is known as the
1920 "HU" algorithm, and is equivalent to value numbering the collapsed
1921 constraint graph including evaluating unions.
1923 The general method of finding equivalence classes is as follows:
1924 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1925 Initialize all non-REF nodes to be direct nodes.
1926 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1928 For each constraint containing the dereference, we also do the same
1931 We then compute SCC's in the graph and unify nodes in the same SCC,
1934 For each non-collapsed node x:
1935 Visit all unvisited explicit incoming edges.
1936 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1938 Lookup the equivalence class for pts(x).
1939 If we found one, equivalence_class(x) = found class.
1940 Otherwise, equivalence_class(x) = new class, and new_class is
1941 added to the lookup table.
1943 All direct nodes with the same equivalence class can be replaced
1944 with a single representative node.
1945 All unlabeled nodes (label == 0) are not pointers and all edges
1946 involving them can be eliminated.
1947 We perform these optimizations during rewrite_constraints
1949 In addition to pointer equivalence class finding, we also perform
1950 location equivalence class finding. This is the set of variables
1951 that always appear together in points-to sets. We use this to
1952 compress the size of the points-to sets. */
1954 /* Current maximum pointer equivalence class id. */
1955 static int pointer_equiv_class
;
1957 /* Current maximum location equivalence class id. */
1958 static int location_equiv_class
;
1960 /* Recursive routine to find strongly connected components in GRAPH,
1961 and label it's nodes with DFS numbers. */
1964 condense_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
1968 unsigned int my_dfs
;
1970 gcc_assert (si
->node_mapping
[n
] == n
);
1971 SET_BIT (si
->visited
, n
);
1972 si
->dfs
[n
] = si
->current_index
++;
1973 my_dfs
= si
->dfs
[n
];
1975 /* Visit all the successors. */
1976 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->preds
[n
], 0, i
, bi
)
1978 unsigned int w
= si
->node_mapping
[i
];
1980 if (TEST_BIT (si
->deleted
, w
))
1983 if (!TEST_BIT (si
->visited
, w
))
1984 condense_visit (graph
, si
, w
);
1986 unsigned int t
= si
->node_mapping
[w
];
1987 unsigned int nnode
= si
->node_mapping
[n
];
1988 gcc_assert (nnode
== n
);
1990 if (si
->dfs
[t
] < si
->dfs
[nnode
])
1991 si
->dfs
[n
] = si
->dfs
[t
];
1995 /* Visit all the implicit predecessors. */
1996 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->implicit_preds
[n
], 0, i
, bi
)
1998 unsigned int w
= si
->node_mapping
[i
];
2000 if (TEST_BIT (si
->deleted
, w
))
2003 if (!TEST_BIT (si
->visited
, w
))
2004 condense_visit (graph
, si
, w
);
2006 unsigned int t
= si
->node_mapping
[w
];
2007 unsigned int nnode
= si
->node_mapping
[n
];
2008 gcc_assert (nnode
== n
);
2010 if (si
->dfs
[t
] < si
->dfs
[nnode
])
2011 si
->dfs
[n
] = si
->dfs
[t
];
2015 /* See if any components have been identified. */
2016 if (si
->dfs
[n
] == my_dfs
)
2018 while (VEC_length (unsigned, si
->scc_stack
) != 0
2019 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
2021 unsigned int w
= VEC_pop (unsigned, si
->scc_stack
);
2022 si
->node_mapping
[w
] = n
;
2024 if (!TEST_BIT (graph
->direct_nodes
, w
))
2025 RESET_BIT (graph
->direct_nodes
, n
);
2027 /* Unify our nodes. */
2028 if (graph
->preds
[w
])
2030 if (!graph
->preds
[n
])
2031 graph
->preds
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2032 bitmap_ior_into (graph
->preds
[n
], graph
->preds
[w
]);
2034 if (graph
->implicit_preds
[w
])
2036 if (!graph
->implicit_preds
[n
])
2037 graph
->implicit_preds
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2038 bitmap_ior_into (graph
->implicit_preds
[n
],
2039 graph
->implicit_preds
[w
]);
2041 if (graph
->points_to
[w
])
2043 if (!graph
->points_to
[n
])
2044 graph
->points_to
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2045 bitmap_ior_into (graph
->points_to
[n
],
2046 graph
->points_to
[w
]);
2049 SET_BIT (si
->deleted
, n
);
2052 VEC_safe_push (unsigned, heap
, si
->scc_stack
, n
);
2055 /* Label pointer equivalences. */
2058 label_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
2062 SET_BIT (si
->visited
, n
);
2064 if (!graph
->points_to
[n
])
2065 graph
->points_to
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2067 /* Label and union our incoming edges's points to sets. */
2068 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->preds
[n
], 0, i
, bi
)
2070 unsigned int w
= si
->node_mapping
[i
];
2071 if (!TEST_BIT (si
->visited
, w
))
2072 label_visit (graph
, si
, w
);
2074 /* Skip unused edges */
2075 if (w
== n
|| graph
->pointer_label
[w
] == 0)
2078 if (graph
->points_to
[w
])
2079 bitmap_ior_into(graph
->points_to
[n
], graph
->points_to
[w
]);
2081 /* Indirect nodes get fresh variables. */
2082 if (!TEST_BIT (graph
->direct_nodes
, n
))
2083 bitmap_set_bit (graph
->points_to
[n
], FIRST_REF_NODE
+ n
);
2085 if (!bitmap_empty_p (graph
->points_to
[n
]))
2087 unsigned int label
= equiv_class_lookup (pointer_equiv_class_table
,
2088 graph
->points_to
[n
]);
2091 label
= pointer_equiv_class
++;
2092 equiv_class_add (pointer_equiv_class_table
,
2093 label
, graph
->points_to
[n
]);
2095 graph
->pointer_label
[n
] = label
;
2099 /* Perform offline variable substitution, discovering equivalence
2100 classes, and eliminating non-pointer variables. */
2102 static struct scc_info
*
2103 perform_var_substitution (constraint_graph_t graph
)
2106 unsigned int size
= graph
->size
;
2107 struct scc_info
*si
= init_scc_info (size
);
2109 bitmap_obstack_initialize (&iteration_obstack
);
2110 pointer_equiv_class_table
= htab_create (511, equiv_class_label_hash
,
2111 equiv_class_label_eq
, free
);
2112 location_equiv_class_table
= htab_create (511, equiv_class_label_hash
,
2113 equiv_class_label_eq
, free
);
2114 pointer_equiv_class
= 1;
2115 location_equiv_class
= 1;
2117 /* Condense the nodes, which means to find SCC's, count incoming
2118 predecessors, and unite nodes in SCC's. */
2119 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2120 if (!TEST_BIT (si
->visited
, si
->node_mapping
[i
]))
2121 condense_visit (graph
, si
, si
->node_mapping
[i
]);
2123 sbitmap_zero (si
->visited
);
2124 /* Actually the label the nodes for pointer equivalences */
2125 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2126 if (!TEST_BIT (si
->visited
, si
->node_mapping
[i
]))
2127 label_visit (graph
, si
, si
->node_mapping
[i
]);
2129 /* Calculate location equivalence labels. */
2130 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2137 if (!graph
->pointed_by
[i
])
2139 pointed_by
= BITMAP_ALLOC (&iteration_obstack
);
2141 /* Translate the pointed-by mapping for pointer equivalence
2143 EXECUTE_IF_SET_IN_BITMAP (graph
->pointed_by
[i
], 0, j
, bi
)
2145 bitmap_set_bit (pointed_by
,
2146 graph
->pointer_label
[si
->node_mapping
[j
]]);
2148 /* The original pointed_by is now dead. */
2149 BITMAP_FREE (graph
->pointed_by
[i
]);
2151 /* Look up the location equivalence label if one exists, or make
2153 label
= equiv_class_lookup (location_equiv_class_table
,
2157 label
= location_equiv_class
++;
2158 equiv_class_add (location_equiv_class_table
,
2163 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2164 fprintf (dump_file
, "Found location equivalence for node %s\n",
2165 get_varinfo (i
)->name
);
2166 BITMAP_FREE (pointed_by
);
2168 graph
->loc_label
[i
] = label
;
2172 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2173 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2175 bool direct_node
= TEST_BIT (graph
->direct_nodes
, i
);
2177 "Equivalence classes for %s node id %d:%s are pointer: %d"
2179 direct_node
? "Direct node" : "Indirect node", i
,
2180 get_varinfo (i
)->name
,
2181 graph
->pointer_label
[si
->node_mapping
[i
]],
2182 graph
->loc_label
[si
->node_mapping
[i
]]);
2185 /* Quickly eliminate our non-pointer variables. */
2187 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2189 unsigned int node
= si
->node_mapping
[i
];
2191 if (graph
->pointer_label
[node
] == 0)
2193 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2195 "%s is a non-pointer variable, eliminating edges.\n",
2196 get_varinfo (node
)->name
);
2197 stats
.nonpointer_vars
++;
2198 clear_edges_for_node (graph
, node
);
2205 /* Free information that was only necessary for variable
2209 free_var_substitution_info (struct scc_info
*si
)
2212 free (graph
->pointer_label
);
2213 free (graph
->loc_label
);
2214 free (graph
->pointed_by
);
2215 free (graph
->points_to
);
2216 free (graph
->eq_rep
);
2217 sbitmap_free (graph
->direct_nodes
);
2218 htab_delete (pointer_equiv_class_table
);
2219 htab_delete (location_equiv_class_table
);
2220 bitmap_obstack_release (&iteration_obstack
);
2223 /* Return an existing node that is equivalent to NODE, which has
2224 equivalence class LABEL, if one exists. Return NODE otherwise. */
2227 find_equivalent_node (constraint_graph_t graph
,
2228 unsigned int node
, unsigned int label
)
2230 /* If the address version of this variable is unused, we can
2231 substitute it for anything else with the same label.
2232 Otherwise, we know the pointers are equivalent, but not the
2233 locations, and we can unite them later. */
2235 if (!bitmap_bit_p (graph
->address_taken
, node
))
2237 gcc_assert (label
< graph
->size
);
2239 if (graph
->eq_rep
[label
] != -1)
2241 /* Unify the two variables since we know they are equivalent. */
2242 if (unite (graph
->eq_rep
[label
], node
))
2243 unify_nodes (graph
, graph
->eq_rep
[label
], node
, false);
2244 return graph
->eq_rep
[label
];
2248 graph
->eq_rep
[label
] = node
;
2249 graph
->pe_rep
[label
] = node
;
2254 gcc_assert (label
< graph
->size
);
2255 graph
->pe
[node
] = label
;
2256 if (graph
->pe_rep
[label
] == -1)
2257 graph
->pe_rep
[label
] = node
;
2263 /* Unite pointer equivalent but not location equivalent nodes in
2264 GRAPH. This may only be performed once variable substitution is
2268 unite_pointer_equivalences (constraint_graph_t graph
)
2272 /* Go through the pointer equivalences and unite them to their
2273 representative, if they aren't already. */
2274 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2276 unsigned int label
= graph
->pe
[i
];
2279 int label_rep
= graph
->pe_rep
[label
];
2281 if (label_rep
== -1)
2284 label_rep
= find (label_rep
);
2285 if (label_rep
>= 0 && unite (label_rep
, find (i
)))
2286 unify_nodes (graph
, label_rep
, i
, false);
2291 /* Move complex constraints to the GRAPH nodes they belong to. */
2294 move_complex_constraints (constraint_graph_t graph
)
2299 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
2303 struct constraint_expr lhs
= c
->lhs
;
2304 struct constraint_expr rhs
= c
->rhs
;
2306 if (lhs
.type
== DEREF
)
2308 insert_into_complex (graph
, lhs
.var
, c
);
2310 else if (rhs
.type
== DEREF
)
2312 if (!(get_varinfo (lhs
.var
)->is_special_var
))
2313 insert_into_complex (graph
, rhs
.var
, c
);
2315 else if (rhs
.type
!= ADDRESSOF
&& lhs
.var
> anything_id
2316 && (lhs
.offset
!= 0 || rhs
.offset
!= 0))
2318 insert_into_complex (graph
, rhs
.var
, c
);
2325 /* Optimize and rewrite complex constraints while performing
2326 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2327 result of perform_variable_substitution. */
2330 rewrite_constraints (constraint_graph_t graph
,
2331 struct scc_info
*si
)
2337 for (j
= 0; j
< graph
->size
; j
++)
2338 gcc_assert (find (j
) == j
);
2340 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
2342 struct constraint_expr lhs
= c
->lhs
;
2343 struct constraint_expr rhs
= c
->rhs
;
2344 unsigned int lhsvar
= find (lhs
.var
);
2345 unsigned int rhsvar
= find (rhs
.var
);
2346 unsigned int lhsnode
, rhsnode
;
2347 unsigned int lhslabel
, rhslabel
;
2349 lhsnode
= si
->node_mapping
[lhsvar
];
2350 rhsnode
= si
->node_mapping
[rhsvar
];
2351 lhslabel
= graph
->pointer_label
[lhsnode
];
2352 rhslabel
= graph
->pointer_label
[rhsnode
];
2354 /* See if it is really a non-pointer variable, and if so, ignore
2358 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2361 fprintf (dump_file
, "%s is a non-pointer variable,"
2362 "ignoring constraint:",
2363 get_varinfo (lhs
.var
)->name
);
2364 dump_constraint (dump_file
, c
);
2366 VEC_replace (constraint_t
, constraints
, i
, NULL
);
2372 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2375 fprintf (dump_file
, "%s is a non-pointer variable,"
2376 "ignoring constraint:",
2377 get_varinfo (rhs
.var
)->name
);
2378 dump_constraint (dump_file
, c
);
2380 VEC_replace (constraint_t
, constraints
, i
, NULL
);
2384 lhsvar
= find_equivalent_node (graph
, lhsvar
, lhslabel
);
2385 rhsvar
= find_equivalent_node (graph
, rhsvar
, rhslabel
);
2386 c
->lhs
.var
= lhsvar
;
2387 c
->rhs
.var
= rhsvar
;
2392 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2393 part of an SCC, false otherwise. */
2396 eliminate_indirect_cycles (unsigned int node
)
2398 if (graph
->indirect_cycles
[node
] != -1
2399 && !bitmap_empty_p (get_varinfo (node
)->solution
))
2402 VEC(unsigned,heap
) *queue
= NULL
;
2404 unsigned int to
= find (graph
->indirect_cycles
[node
]);
2407 /* We can't touch the solution set and call unify_nodes
2408 at the same time, because unify_nodes is going to do
2409 bitmap unions into it. */
2411 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node
)->solution
, 0, i
, bi
)
2413 if (find (i
) == i
&& i
!= to
)
2416 VEC_safe_push (unsigned, heap
, queue
, i
);
2421 VEC_iterate (unsigned, queue
, queuepos
, i
);
2424 unify_nodes (graph
, to
, i
, true);
2426 VEC_free (unsigned, heap
, queue
);
2432 /* Solve the constraint graph GRAPH using our worklist solver.
2433 This is based on the PW* family of solvers from the "Efficient Field
2434 Sensitive Pointer Analysis for C" paper.
2435 It works by iterating over all the graph nodes, processing the complex
2436 constraints and propagating the copy constraints, until everything stops
2437 changed. This corresponds to steps 6-8 in the solving list given above. */
2440 solve_graph (constraint_graph_t graph
)
2442 unsigned int size
= graph
->size
;
2447 changed
= sbitmap_alloc (size
);
2448 sbitmap_zero (changed
);
2450 /* Mark all initial non-collapsed nodes as changed. */
2451 for (i
= 0; i
< size
; i
++)
2453 varinfo_t ivi
= get_varinfo (i
);
2454 if (find (i
) == i
&& !bitmap_empty_p (ivi
->solution
)
2455 && ((graph
->succs
[i
] && !bitmap_empty_p (graph
->succs
[i
]))
2456 || VEC_length (constraint_t
, graph
->complex[i
]) > 0))
2458 SET_BIT (changed
, i
);
2463 /* Allocate a bitmap to be used to store the changed bits. */
2464 pts
= BITMAP_ALLOC (&pta_obstack
);
2466 while (changed_count
> 0)
2469 struct topo_info
*ti
= init_topo_info ();
2472 bitmap_obstack_initialize (&iteration_obstack
);
2474 compute_topo_order (graph
, ti
);
2476 while (VEC_length (unsigned, ti
->topo_order
) != 0)
2479 i
= VEC_pop (unsigned, ti
->topo_order
);
2481 /* If this variable is not a representative, skip it. */
2485 /* In certain indirect cycle cases, we may merge this
2486 variable to another. */
2487 if (eliminate_indirect_cycles (i
) && find (i
) != i
)
2490 /* If the node has changed, we need to process the
2491 complex constraints and outgoing edges again. */
2492 if (TEST_BIT (changed
, i
))
2497 VEC(constraint_t
,heap
) *complex = graph
->complex[i
];
2498 bool solution_empty
;
2500 RESET_BIT (changed
, i
);
2503 /* Compute the changed set of solution bits. */
2504 bitmap_and_compl (pts
, get_varinfo (i
)->solution
,
2505 get_varinfo (i
)->oldsolution
);
2507 if (bitmap_empty_p (pts
))
2510 bitmap_ior_into (get_varinfo (i
)->oldsolution
, pts
);
2512 solution
= get_varinfo (i
)->solution
;
2513 solution_empty
= bitmap_empty_p (solution
);
2515 /* Process the complex constraints */
2516 for (j
= 0; VEC_iterate (constraint_t
, complex, j
, c
); j
++)
2518 /* XXX: This is going to unsort the constraints in
2519 some cases, which will occasionally add duplicate
2520 constraints during unification. This does not
2521 affect correctness. */
2522 c
->lhs
.var
= find (c
->lhs
.var
);
2523 c
->rhs
.var
= find (c
->rhs
.var
);
2525 /* The only complex constraint that can change our
2526 solution to non-empty, given an empty solution,
2527 is a constraint where the lhs side is receiving
2528 some set from elsewhere. */
2529 if (!solution_empty
|| c
->lhs
.type
!= DEREF
)
2530 do_complex_constraint (graph
, c
, pts
);
2533 solution_empty
= bitmap_empty_p (solution
);
2535 if (!solution_empty
)
2538 unsigned eff_escaped_id
= find (escaped_id
);
2540 /* Propagate solution to all successors. */
2541 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->succs
[i
],
2547 unsigned int to
= find (j
);
2548 tmp
= get_varinfo (to
)->solution
;
2551 /* Don't try to propagate to ourselves. */
2555 /* If we propagate from ESCAPED use ESCAPED as
2557 if (i
== eff_escaped_id
)
2558 flag
= bitmap_set_bit (tmp
, escaped_id
);
2560 flag
= set_union_with_increment (tmp
, pts
, 0);
2564 get_varinfo (to
)->solution
= tmp
;
2565 if (!TEST_BIT (changed
, to
))
2567 SET_BIT (changed
, to
);
2575 free_topo_info (ti
);
2576 bitmap_obstack_release (&iteration_obstack
);
2580 sbitmap_free (changed
);
2581 bitmap_obstack_release (&oldpta_obstack
);
2584 /* Map from trees to variable infos. */
2585 static struct pointer_map_t
*vi_for_tree
;
2588 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2591 insert_vi_for_tree (tree t
, varinfo_t vi
)
2593 void **slot
= pointer_map_insert (vi_for_tree
, t
);
2595 gcc_assert (*slot
== NULL
);
2599 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2600 exist in the map, return NULL, otherwise, return the varinfo we found. */
2603 lookup_vi_for_tree (tree t
)
2605 void **slot
= pointer_map_contains (vi_for_tree
, t
);
2609 return (varinfo_t
) *slot
;
2612 /* Return a printable name for DECL */
2615 alias_get_name (tree decl
)
2617 const char *res
= get_name (decl
);
2619 int num_printed
= 0;
2628 if (TREE_CODE (decl
) == SSA_NAME
)
2630 num_printed
= asprintf (&temp
, "%s_%u",
2631 alias_get_name (SSA_NAME_VAR (decl
)),
2632 SSA_NAME_VERSION (decl
));
2634 else if (DECL_P (decl
))
2636 num_printed
= asprintf (&temp
, "D.%u", DECL_UID (decl
));
2638 if (num_printed
> 0)
2640 res
= ggc_strdup (temp
);
2646 /* Find the variable id for tree T in the map.
2647 If T doesn't exist in the map, create an entry for it and return it. */
2650 get_vi_for_tree (tree t
)
2652 void **slot
= pointer_map_contains (vi_for_tree
, t
);
2654 return get_varinfo (create_variable_info_for (t
, alias_get_name (t
)));
2656 return (varinfo_t
) *slot
;
2659 /* Get a constraint expression for a new temporary variable. */
2661 static struct constraint_expr
2662 get_constraint_exp_for_temp (tree t
)
2664 struct constraint_expr cexpr
;
2666 gcc_assert (SSA_VAR_P (t
));
2668 cexpr
.type
= SCALAR
;
2669 cexpr
.var
= get_vi_for_tree (t
)->id
;
2675 /* Get a constraint expression vector from an SSA_VAR_P node.
2676 If address_p is true, the result will be taken its address of. */
2679 get_constraint_for_ssa_var (tree t
, VEC(ce_s
, heap
) **results
, bool address_p
)
2681 struct constraint_expr cexpr
;
2684 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2685 gcc_assert (SSA_VAR_P (t
) || DECL_P (t
));
2687 /* For parameters, get at the points-to set for the actual parm
2689 if (TREE_CODE (t
) == SSA_NAME
2690 && TREE_CODE (SSA_NAME_VAR (t
)) == PARM_DECL
2691 && SSA_NAME_IS_DEFAULT_DEF (t
))
2693 get_constraint_for_ssa_var (SSA_NAME_VAR (t
), results
, address_p
);
2697 vi
= get_vi_for_tree (t
);
2699 cexpr
.type
= SCALAR
;
2701 /* If we determine the result is "anything", and we know this is readonly,
2702 say it points to readonly memory instead. */
2703 if (cexpr
.var
== anything_id
&& TREE_READONLY (t
))
2706 cexpr
.type
= ADDRESSOF
;
2707 cexpr
.var
= readonly_id
;
2710 /* If we are not taking the address of the constraint expr, add all
2711 sub-fiels of the variable as well. */
2714 for (; vi
; vi
= vi
->next
)
2717 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
2722 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
2725 /* Process constraint T, performing various simplifications and then
2726 adding it to our list of overall constraints. */
2729 process_constraint (constraint_t t
)
2731 struct constraint_expr rhs
= t
->rhs
;
2732 struct constraint_expr lhs
= t
->lhs
;
2734 gcc_assert (rhs
.var
< VEC_length (varinfo_t
, varmap
));
2735 gcc_assert (lhs
.var
< VEC_length (varinfo_t
, varmap
));
2737 /* If we didn't get any useful constraint from the lhs we get
2738 &ANYTHING as fallback from get_constraint_for. Deal with
2739 it here by turning it into *ANYTHING. */
2740 if (lhs
.type
== ADDRESSOF
2741 && lhs
.var
== anything_id
)
2744 /* ADDRESSOF on the lhs is invalid. */
2745 gcc_assert (lhs
.type
!= ADDRESSOF
);
2747 /* This can happen in our IR with things like n->a = *p */
2748 if (rhs
.type
== DEREF
&& lhs
.type
== DEREF
&& rhs
.var
!= anything_id
)
2750 /* Split into tmp = *rhs, *lhs = tmp */
2751 tree rhsdecl
= get_varinfo (rhs
.var
)->decl
;
2752 tree pointertype
= TREE_TYPE (rhsdecl
);
2753 tree pointedtotype
= TREE_TYPE (pointertype
);
2754 tree tmpvar
= create_tmp_var_raw (pointedtotype
, "doubledereftmp");
2755 struct constraint_expr tmplhs
= get_constraint_exp_for_temp (tmpvar
);
2757 process_constraint (new_constraint (tmplhs
, rhs
));
2758 process_constraint (new_constraint (lhs
, tmplhs
));
2760 else if (rhs
.type
== ADDRESSOF
&& lhs
.type
== DEREF
)
2762 /* Split into tmp = &rhs, *lhs = tmp */
2763 tree rhsdecl
= get_varinfo (rhs
.var
)->decl
;
2764 tree pointertype
= TREE_TYPE (rhsdecl
);
2765 tree tmpvar
= create_tmp_var_raw (pointertype
, "derefaddrtmp");
2766 struct constraint_expr tmplhs
= get_constraint_exp_for_temp (tmpvar
);
2768 process_constraint (new_constraint (tmplhs
, rhs
));
2769 process_constraint (new_constraint (lhs
, tmplhs
));
2773 gcc_assert (rhs
.type
!= ADDRESSOF
|| rhs
.offset
== 0);
2774 VEC_safe_push (constraint_t
, heap
, constraints
, t
);
2778 /* Return true if T is a type that could contain pointers. */
2781 type_could_have_pointers (tree type
)
2783 if (POINTER_TYPE_P (type
))
2786 if (TREE_CODE (type
) == ARRAY_TYPE
)
2787 return type_could_have_pointers (TREE_TYPE (type
));
2789 return AGGREGATE_TYPE_P (type
);
2792 /* Return true if T is a variable of a type that could contain
2796 could_have_pointers (tree t
)
2798 return type_could_have_pointers (TREE_TYPE (t
));
2801 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2804 static HOST_WIDE_INT
2805 bitpos_of_field (const tree fdecl
)
2808 if (!host_integerp (DECL_FIELD_OFFSET (fdecl
), 0)
2809 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl
), 0))
2812 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl
)) * 8
2813 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl
)));
2817 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2818 resulting constraint expressions in *RESULTS. */
2821 get_constraint_for_ptr_offset (tree ptr
, tree offset
,
2822 VEC (ce_s
, heap
) **results
)
2824 struct constraint_expr
*c
;
2826 HOST_WIDE_INT rhsunitoffset
, rhsoffset
;
2828 /* If we do not do field-sensitive PTA adding offsets to pointers
2829 does not change the points-to solution. */
2830 if (!use_field_sensitive
)
2832 get_constraint_for (ptr
, results
);
2836 /* If the offset is not a non-negative integer constant that fits
2837 in a HOST_WIDE_INT, we have to fall back to a conservative
2838 solution which includes all sub-fields of all pointed-to
2839 variables of ptr. */
2840 if (!host_integerp (offset
, 0))
2841 rhsoffset
= UNKNOWN_OFFSET
;
2844 /* Make sure the bit-offset also fits. */
2845 rhsunitoffset
= TREE_INT_CST_LOW (offset
);
2846 rhsoffset
= rhsunitoffset
* BITS_PER_UNIT
;
2847 if (rhsunitoffset
!= rhsoffset
/ BITS_PER_UNIT
)
2848 rhsoffset
= UNKNOWN_OFFSET
;
2851 get_constraint_for (ptr
, results
);
2855 /* As we are eventually appending to the solution do not use
2856 VEC_iterate here. */
2857 n
= VEC_length (ce_s
, *results
);
2858 for (j
= 0; j
< n
; j
++)
2861 c
= VEC_index (ce_s
, *results
, j
);
2862 curr
= get_varinfo (c
->var
);
2864 if (c
->type
== ADDRESSOF
2865 /* If this varinfo represents a full variable just use it. */
2866 && curr
->is_full_var
)
2868 else if (c
->type
== ADDRESSOF
2869 /* If we do not know the offset add all subfields. */
2870 && rhsoffset
== UNKNOWN_OFFSET
)
2872 varinfo_t temp
= lookup_vi_for_tree (curr
->decl
);
2875 struct constraint_expr c2
;
2877 c2
.type
= ADDRESSOF
;
2879 VEC_safe_push (ce_s
, heap
, *results
, &c2
);
2884 else if (c
->type
== ADDRESSOF
)
2887 unsigned HOST_WIDE_INT offset
= curr
->offset
+ rhsoffset
;
2889 /* Search the sub-field which overlaps with the
2890 pointed-to offset. If the result is outside of the variable
2891 we have to provide a conservative result, as the variable is
2892 still reachable from the resulting pointer (even though it
2893 technically cannot point to anything). The last and first
2894 sub-fields are such conservative results.
2895 ??? If we always had a sub-field for &object + 1 then
2896 we could represent this in a more precise way. */
2898 && curr
->offset
< offset
)
2900 temp
= first_or_preceding_vi_for_offset (curr
, offset
);
2902 /* If the found variable is not exactly at the pointed to
2903 result, we have to include the next variable in the
2904 solution as well. Otherwise two increments by offset / 2
2905 do not result in the same or a conservative superset
2907 if (temp
->offset
!= offset
2908 && temp
->next
!= NULL
)
2910 struct constraint_expr c2
;
2911 c2
.var
= temp
->next
->id
;
2912 c2
.type
= ADDRESSOF
;
2914 VEC_safe_push (ce_s
, heap
, *results
, &c2
);
2920 c
->offset
= rhsoffset
;
2925 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2926 If address_p is true the result will be taken its address of. */
2929 get_constraint_for_component_ref (tree t
, VEC(ce_s
, heap
) **results
,
2933 HOST_WIDE_INT bitsize
= -1;
2934 HOST_WIDE_INT bitmaxsize
= -1;
2935 HOST_WIDE_INT bitpos
;
2937 struct constraint_expr
*result
;
2939 /* Some people like to do cute things like take the address of
2942 while (!SSA_VAR_P (forzero
) && !CONSTANT_CLASS_P (forzero
))
2943 forzero
= TREE_OPERAND (forzero
, 0);
2945 if (CONSTANT_CLASS_P (forzero
) && integer_zerop (forzero
))
2947 struct constraint_expr temp
;
2950 temp
.var
= integer_id
;
2952 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
2956 t
= get_ref_base_and_extent (t
, &bitpos
, &bitsize
, &bitmaxsize
);
2958 /* Pretend to take the address of the base, we'll take care of
2959 adding the required subset of sub-fields below. */
2960 get_constraint_for_1 (t
, results
, true);
2961 gcc_assert (VEC_length (ce_s
, *results
) == 1);
2962 result
= VEC_last (ce_s
, *results
);
2964 if (result
->type
== SCALAR
2965 && get_varinfo (result
->var
)->is_full_var
)
2966 /* For single-field vars do not bother about the offset. */
2968 else if (result
->type
== SCALAR
)
2970 /* In languages like C, you can access one past the end of an
2971 array. You aren't allowed to dereference it, so we can
2972 ignore this constraint. When we handle pointer subtraction,
2973 we may have to do something cute here. */
2975 if ((unsigned HOST_WIDE_INT
)bitpos
< get_varinfo (result
->var
)->fullsize
2978 /* It's also not true that the constraint will actually start at the
2979 right offset, it may start in some padding. We only care about
2980 setting the constraint to the first actual field it touches, so
2982 struct constraint_expr cexpr
= *result
;
2984 VEC_pop (ce_s
, *results
);
2986 for (curr
= get_varinfo (cexpr
.var
); curr
; curr
= curr
->next
)
2988 if (ranges_overlap_p (curr
->offset
, curr
->size
,
2989 bitpos
, bitmaxsize
))
2991 cexpr
.var
= curr
->id
;
2992 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
2997 /* If we are going to take the address of this field then
2998 to be able to compute reachability correctly add at least
2999 the last field of the variable. */
3001 && VEC_length (ce_s
, *results
) == 0)
3003 curr
= get_varinfo (cexpr
.var
);
3004 while (curr
->next
!= NULL
)
3006 cexpr
.var
= curr
->id
;
3007 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
3010 /* Assert that we found *some* field there. The user couldn't be
3011 accessing *only* padding. */
3012 /* Still the user could access one past the end of an array
3013 embedded in a struct resulting in accessing *only* padding. */
3014 gcc_assert (VEC_length (ce_s
, *results
) >= 1
3015 || ref_contains_array_ref (orig_t
));
3017 else if (bitmaxsize
== 0)
3019 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3020 fprintf (dump_file
, "Access to zero-sized part of variable,"
3024 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3025 fprintf (dump_file
, "Access to past the end of variable, ignoring\n");
3027 else if (result
->type
== DEREF
)
3029 /* If we do not know exactly where the access goes say so. Note
3030 that only for non-structure accesses we know that we access
3031 at most one subfiled of any variable. */
3033 || bitsize
!= bitmaxsize
3034 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t
)))
3035 result
->offset
= UNKNOWN_OFFSET
;
3037 result
->offset
= bitpos
;
3039 else if (result
->type
== ADDRESSOF
)
3041 /* We can end up here for component references on a
3042 VIEW_CONVERT_EXPR <>(&foobar). */
3043 result
->type
= SCALAR
;
3044 result
->var
= anything_id
;
3052 /* Dereference the constraint expression CONS, and return the result.
3053 DEREF (ADDRESSOF) = SCALAR
3054 DEREF (SCALAR) = DEREF
3055 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3056 This is needed so that we can handle dereferencing DEREF constraints. */
3059 do_deref (VEC (ce_s
, heap
) **constraints
)
3061 struct constraint_expr
*c
;
3064 for (i
= 0; VEC_iterate (ce_s
, *constraints
, i
, c
); i
++)
3066 if (c
->type
== SCALAR
)
3068 else if (c
->type
== ADDRESSOF
)
3070 else if (c
->type
== DEREF
)
3072 tree tmpvar
= create_tmp_var_raw (ptr_type_node
, "dereftmp");
3073 struct constraint_expr tmplhs
= get_constraint_exp_for_temp (tmpvar
);
3074 process_constraint (new_constraint (tmplhs
, *c
));
3075 c
->var
= tmplhs
.var
;
3082 /* Given a tree T, return the constraint expression for it. */
3085 get_constraint_for_1 (tree t
, VEC (ce_s
, heap
) **results
, bool address_p
)
3087 struct constraint_expr temp
;
3089 /* x = integer is all glommed to a single variable, which doesn't
3090 point to anything by itself. That is, of course, unless it is an
3091 integer constant being treated as a pointer, in which case, we
3092 will return that this is really the addressof anything. This
3093 happens below, since it will fall into the default case. The only
3094 case we know something about an integer treated like a pointer is
3095 when it is the NULL pointer, and then we just say it points to
3098 Do not do that if -fno-delete-null-pointer-checks though, because
3099 in that case *NULL does not fail, so it _should_ alias *anything.
3100 It is not worth adding a new option or renaming the existing one,
3101 since this case is relatively obscure. */
3102 if (flag_delete_null_pointer_checks
3103 && ((TREE_CODE (t
) == INTEGER_CST
3104 && integer_zerop (t
))
3105 /* The only valid CONSTRUCTORs in gimple with pointer typed
3106 elements are zero-initializer. */
3107 || TREE_CODE (t
) == CONSTRUCTOR
))
3109 temp
.var
= nothing_id
;
3110 temp
.type
= ADDRESSOF
;
3112 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3116 /* String constants are read-only. */
3117 if (TREE_CODE (t
) == STRING_CST
)
3119 temp
.var
= readonly_id
;
3122 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3126 switch (TREE_CODE_CLASS (TREE_CODE (t
)))
3128 case tcc_expression
:
3130 switch (TREE_CODE (t
))
3134 struct constraint_expr
*c
;
3136 tree exp
= TREE_OPERAND (t
, 0);
3138 get_constraint_for_1 (exp
, results
, true);
3140 for (i
= 0; VEC_iterate (ce_s
, *results
, i
, c
); i
++)
3142 if (c
->type
== DEREF
)
3145 c
->type
= ADDRESSOF
;
3156 switch (TREE_CODE (t
))
3160 get_constraint_for_1 (TREE_OPERAND (t
, 0), results
, address_p
);
3165 case ARRAY_RANGE_REF
:
3167 get_constraint_for_component_ref (t
, results
, address_p
);
3169 case VIEW_CONVERT_EXPR
:
3170 get_constraint_for_1 (TREE_OPERAND (t
, 0), results
, address_p
);
3172 /* We are missing handling for TARGET_MEM_REF here. */
3177 case tcc_exceptional
:
3179 switch (TREE_CODE (t
))
3183 get_constraint_for_ssa_var (t
, results
, address_p
);
3190 case tcc_declaration
:
3192 get_constraint_for_ssa_var (t
, results
, address_p
);
3198 /* The default fallback is a constraint from anything. */
3199 temp
.type
= ADDRESSOF
;
3200 temp
.var
= anything_id
;
3202 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3205 /* Given a gimple tree T, return the constraint expression vector for it. */
3208 get_constraint_for (tree t
, VEC (ce_s
, heap
) **results
)
3210 gcc_assert (VEC_length (ce_s
, *results
) == 0);
3212 get_constraint_for_1 (t
, results
, false);
3215 /* Handle aggregate copies by expanding into copies of the respective
3216 fields of the structures. */
3219 do_structure_copy (tree lhsop
, tree rhsop
)
3221 struct constraint_expr
*lhsp
, *rhsp
;
3222 VEC (ce_s
, heap
) *lhsc
= NULL
, *rhsc
= NULL
;
3225 get_constraint_for (lhsop
, &lhsc
);
3226 get_constraint_for (rhsop
, &rhsc
);
3227 lhsp
= VEC_index (ce_s
, lhsc
, 0);
3228 rhsp
= VEC_index (ce_s
, rhsc
, 0);
3229 if (lhsp
->type
== DEREF
3230 || (lhsp
->type
== ADDRESSOF
&& lhsp
->var
== anything_id
)
3231 || rhsp
->type
== DEREF
)
3233 struct constraint_expr tmp
;
3234 tree tmpvar
= create_tmp_var_raw (ptr_type_node
,
3235 "structcopydereftmp");
3236 tmp
.var
= get_vi_for_tree (tmpvar
)->id
;
3239 for (j
= 0; VEC_iterate (ce_s
, rhsc
, j
, rhsp
); ++j
)
3240 process_constraint (new_constraint (tmp
, *rhsp
));
3241 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); ++j
)
3242 process_constraint (new_constraint (*lhsp
, tmp
));
3244 else if (lhsp
->type
== SCALAR
3245 && (rhsp
->type
== SCALAR
3246 || rhsp
->type
== ADDRESSOF
))
3248 tree lhsbase
, rhsbase
;
3249 HOST_WIDE_INT lhssize
, lhsmaxsize
, lhsoffset
;
3250 HOST_WIDE_INT rhssize
, rhsmaxsize
, rhsoffset
;
3252 lhsbase
= get_ref_base_and_extent (lhsop
, &lhsoffset
,
3253 &lhssize
, &lhsmaxsize
);
3254 rhsbase
= get_ref_base_and_extent (rhsop
, &rhsoffset
,
3255 &rhssize
, &rhsmaxsize
);
3256 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
);)
3258 varinfo_t lhsv
, rhsv
;
3259 rhsp
= VEC_index (ce_s
, rhsc
, k
);
3260 lhsv
= get_varinfo (lhsp
->var
);
3261 rhsv
= get_varinfo (rhsp
->var
);
3262 if (lhsv
->may_have_pointers
3263 && ranges_overlap_p (lhsv
->offset
+ rhsoffset
, lhsv
->size
,
3264 rhsv
->offset
+ lhsoffset
, rhsv
->size
))
3265 process_constraint (new_constraint (*lhsp
, *rhsp
));
3266 if (lhsv
->offset
+ rhsoffset
+ lhsv
->size
3267 > rhsv
->offset
+ lhsoffset
+ rhsv
->size
)
3270 if (k
>= VEC_length (ce_s
, rhsc
))
3280 VEC_free (ce_s
, heap
, lhsc
);
3281 VEC_free (ce_s
, heap
, rhsc
);
3284 /* Create a constraint ID = OP. */
3287 make_constraint_to (unsigned id
, tree op
)
3289 VEC(ce_s
, heap
) *rhsc
= NULL
;
3290 struct constraint_expr
*c
;
3291 struct constraint_expr includes
;
3295 includes
.offset
= 0;
3296 includes
.type
= SCALAR
;
3298 get_constraint_for (op
, &rhsc
);
3299 for (j
= 0; VEC_iterate (ce_s
, rhsc
, j
, c
); j
++)
3300 process_constraint (new_constraint (includes
, *c
));
3301 VEC_free (ce_s
, heap
, rhsc
);
3304 /* Make constraints necessary to make OP escape. */
3307 make_escape_constraint (tree op
)
3309 make_constraint_to (escaped_id
, op
);
3312 /* For non-IPA mode, generate constraints necessary for a call on the
3316 handle_rhs_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3318 struct constraint_expr rhsc
;
3321 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
3323 tree arg
= gimple_call_arg (stmt
, i
);
3325 /* Find those pointers being passed, and make sure they end up
3326 pointing to anything. */
3327 if (could_have_pointers (arg
))
3328 make_escape_constraint (arg
);
3331 /* The static chain escapes as well. */
3332 if (gimple_call_chain (stmt
))
3333 make_escape_constraint (gimple_call_chain (stmt
));
3335 /* Regular functions return nonlocal memory. */
3336 rhsc
.var
= nonlocal_id
;
3339 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3342 /* For non-IPA mode, generate constraints necessary for a call
3343 that returns a pointer and assigns it to LHS. This simply makes
3344 the LHS point to global and escaped variables. */
3347 handle_lhs_call (tree lhs
, int flags
, VEC(ce_s
, heap
) *rhsc
)
3349 VEC(ce_s
, heap
) *lhsc
= NULL
;
3351 struct constraint_expr
*lhsp
;
3353 get_constraint_for (lhs
, &lhsc
);
3355 if (flags
& ECF_MALLOC
)
3357 struct constraint_expr rhsc
;
3358 tree heapvar
= heapvar_lookup (lhs
);
3361 if (heapvar
== NULL
)
3363 heapvar
= create_tmp_var_raw (ptr_type_node
, "HEAP");
3364 DECL_EXTERNAL (heapvar
) = 1;
3365 get_var_ann (heapvar
)->is_heapvar
= 1;
3366 if (gimple_referenced_vars (cfun
))
3367 add_referenced_var (heapvar
);
3368 heapvar_insert (lhs
, heapvar
);
3371 rhsc
.var
= create_variable_info_for (heapvar
,
3372 alias_get_name (heapvar
));
3373 vi
= get_varinfo (rhsc
.var
);
3374 vi
->is_artificial_var
= 1;
3375 vi
->is_heap_var
= 1;
3376 vi
->is_unknown_size_var
= true;
3379 rhsc
.type
= ADDRESSOF
;
3381 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); j
++)
3382 process_constraint (new_constraint (*lhsp
, rhsc
));
3384 else if (VEC_length (ce_s
, rhsc
) > 0)
3386 struct constraint_expr
*lhsp
, *rhsp
;
3388 /* If the store is to a global decl make sure to
3389 add proper escape constraints. */
3390 lhs
= get_base_address (lhs
);
3393 && is_global_var (lhs
))
3395 struct constraint_expr tmpc
;
3396 tmpc
.var
= escaped_id
;
3399 VEC_safe_push (ce_s
, heap
, lhsc
, &tmpc
);
3401 for (i
= 0; VEC_iterate (ce_s
, lhsc
, i
, lhsp
); ++i
)
3402 for (j
= 0; VEC_iterate (ce_s
, rhsc
, j
, rhsp
); ++j
)
3403 process_constraint (new_constraint (*lhsp
, *rhsp
));
3405 VEC_free (ce_s
, heap
, lhsc
);
3408 /* For non-IPA mode, generate constraints necessary for a call of a
3409 const function that returns a pointer in the statement STMT. */
3412 handle_const_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3414 struct constraint_expr rhsc
, tmpc
;
3415 tree tmpvar
= NULL_TREE
;
3418 /* Treat nested const functions the same as pure functions as far
3419 as the static chain is concerned. */
3420 if (gimple_call_chain (stmt
))
3422 make_constraint_to (callused_id
, gimple_call_chain (stmt
));
3423 rhsc
.var
= callused_id
;
3426 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3429 /* May return arguments. */
3430 for (k
= 0; k
< gimple_call_num_args (stmt
); ++k
)
3432 tree arg
= gimple_call_arg (stmt
, k
);
3434 if (could_have_pointers (arg
))
3436 VEC(ce_s
, heap
) *argc
= NULL
;
3437 struct constraint_expr
*argp
;
3440 /* We always use a temporary here, otherwise we end up with
3441 a quadratic amount of constraints for
3442 large_struct = const_call (large_struct);
3443 with field-sensitive PTA. */
3444 if (tmpvar
== NULL_TREE
)
3446 tmpvar
= create_tmp_var_raw (ptr_type_node
, "consttmp");
3447 tmpc
= get_constraint_exp_for_temp (tmpvar
);
3450 get_constraint_for (arg
, &argc
);
3451 for (i
= 0; VEC_iterate (ce_s
, argc
, i
, argp
); i
++)
3452 process_constraint (new_constraint (tmpc
, *argp
));
3453 VEC_free (ce_s
, heap
, argc
);
3456 if (tmpvar
!= NULL_TREE
)
3457 VEC_safe_push (ce_s
, heap
, *results
, &tmpc
);
3459 /* May return addresses of globals. */
3460 rhsc
.var
= nonlocal_id
;
3462 rhsc
.type
= ADDRESSOF
;
3463 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3466 /* For non-IPA mode, generate constraints necessary for a call to a
3467 pure function in statement STMT. */
3470 handle_pure_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3472 struct constraint_expr rhsc
;
3474 bool need_callused
= false;
3476 /* Memory reached from pointer arguments is call-used. */
3477 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
3479 tree arg
= gimple_call_arg (stmt
, i
);
3481 if (could_have_pointers (arg
))
3483 make_constraint_to (callused_id
, arg
);
3484 need_callused
= true;
3488 /* The static chain is used as well. */
3489 if (gimple_call_chain (stmt
))
3491 make_constraint_to (callused_id
, gimple_call_chain (stmt
));
3492 need_callused
= true;
3495 /* Pure functions may return callused and nonlocal memory. */
3498 rhsc
.var
= callused_id
;
3501 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3503 rhsc
.var
= nonlocal_id
;
3506 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3509 /* Walk statement T setting up aliasing constraints according to the
3510 references found in T. This function is the main part of the
3511 constraint builder. AI points to auxiliary alias information used
3512 when building alias sets and computing alias grouping heuristics. */
3515 find_func_aliases (gimple origt
)
3518 VEC(ce_s
, heap
) *lhsc
= NULL
;
3519 VEC(ce_s
, heap
) *rhsc
= NULL
;
3520 struct constraint_expr
*c
;
3521 enum escape_type stmt_escape_type
;
3523 /* Now build constraints expressions. */
3524 if (gimple_code (t
) == GIMPLE_PHI
)
3526 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t
))));
3528 /* Only care about pointers and structures containing
3530 if (could_have_pointers (gimple_phi_result (t
)))
3535 /* For a phi node, assign all the arguments to
3537 get_constraint_for (gimple_phi_result (t
), &lhsc
);
3538 for (i
= 0; i
< gimple_phi_num_args (t
); i
++)
3541 tree strippedrhs
= PHI_ARG_DEF (t
, i
);
3543 STRIP_NOPS (strippedrhs
);
3544 rhstype
= TREE_TYPE (strippedrhs
);
3545 get_constraint_for (gimple_phi_arg_def (t
, i
), &rhsc
);
3547 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, c
); j
++)
3549 struct constraint_expr
*c2
;
3550 while (VEC_length (ce_s
, rhsc
) > 0)
3552 c2
= VEC_last (ce_s
, rhsc
);
3553 process_constraint (new_constraint (*c
, *c2
));
3554 VEC_pop (ce_s
, rhsc
);
3560 /* In IPA mode, we need to generate constraints to pass call
3561 arguments through their calls. There are two cases,
3562 either a GIMPLE_CALL returning a value, or just a plain
3563 GIMPLE_CALL when we are not.
3565 In non-ipa mode, we need to generate constraints for each
3566 pointer passed by address. */
3567 else if (is_gimple_call (t
))
3571 VEC(ce_s
, heap
) *rhsc
= NULL
;
3572 int flags
= gimple_call_flags (t
);
3574 /* Const functions can return their arguments and addresses
3575 of global memory but not of escaped memory. */
3576 if (flags
& (ECF_CONST
|ECF_NOVOPS
))
3578 if (gimple_call_lhs (t
)
3579 && could_have_pointers (gimple_call_lhs (t
)))
3580 handle_const_call (t
, &rhsc
);
3582 /* Pure functions can return addresses in and of memory
3583 reachable from their arguments, but they are not an escape
3584 point for reachable memory of their arguments. */
3585 else if (flags
& (ECF_PURE
|ECF_LOOPING_CONST_OR_PURE
))
3586 handle_pure_call (t
, &rhsc
);
3588 handle_rhs_call (t
, &rhsc
);
3589 if (gimple_call_lhs (t
)
3590 && could_have_pointers (gimple_call_lhs (t
)))
3591 handle_lhs_call (gimple_call_lhs (t
), flags
, rhsc
);
3592 VEC_free (ce_s
, heap
, rhsc
);
3602 lhsop
= gimple_call_lhs (t
);
3603 decl
= gimple_call_fndecl (t
);
3605 /* If we can directly resolve the function being called, do so.
3606 Otherwise, it must be some sort of indirect expression that
3607 we should still be able to handle. */
3609 fi
= get_vi_for_tree (decl
);
3612 decl
= gimple_call_fn (t
);
3613 fi
= get_vi_for_tree (decl
);
3616 /* Assign all the passed arguments to the appropriate incoming
3617 parameters of the function. */
3618 for (j
= 0; j
< gimple_call_num_args (t
); j
++)
3620 struct constraint_expr lhs
;
3621 struct constraint_expr
*rhsp
;
3622 tree arg
= gimple_call_arg (t
, j
);
3624 get_constraint_for (arg
, &rhsc
);
3625 if (TREE_CODE (decl
) != FUNCTION_DECL
)
3634 lhs
.var
= first_vi_for_offset (fi
, i
)->id
;
3637 while (VEC_length (ce_s
, rhsc
) != 0)
3639 rhsp
= VEC_last (ce_s
, rhsc
);
3640 process_constraint (new_constraint (lhs
, *rhsp
));
3641 VEC_pop (ce_s
, rhsc
);
3646 /* If we are returning a value, assign it to the result. */
3649 struct constraint_expr rhs
;
3650 struct constraint_expr
*lhsp
;
3653 get_constraint_for (lhsop
, &lhsc
);
3654 if (TREE_CODE (decl
) != FUNCTION_DECL
)
3663 rhs
.var
= first_vi_for_offset (fi
, i
)->id
;
3666 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); j
++)
3667 process_constraint (new_constraint (*lhsp
, rhs
));
3671 /* Otherwise, just a regular assignment statement. Only care about
3672 operations with pointer result, others are dealt with as escape
3673 points if they have pointer operands. */
3674 else if (is_gimple_assign (t
)
3675 && could_have_pointers (gimple_assign_lhs (t
)))
3677 /* Otherwise, just a regular assignment statement. */
3678 tree lhsop
= gimple_assign_lhs (t
);
3679 tree rhsop
= (gimple_num_ops (t
) == 2) ? gimple_assign_rhs1 (t
) : NULL
;
3681 if (rhsop
&& AGGREGATE_TYPE_P (TREE_TYPE (lhsop
)))
3682 do_structure_copy (lhsop
, rhsop
);
3686 struct constraint_expr temp
;
3687 get_constraint_for (lhsop
, &lhsc
);
3689 if (gimple_assign_rhs_code (t
) == POINTER_PLUS_EXPR
)
3690 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t
),
3691 gimple_assign_rhs2 (t
), &rhsc
);
3692 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t
))
3693 && !(POINTER_TYPE_P (gimple_expr_type (t
))
3694 && !POINTER_TYPE_P (TREE_TYPE (rhsop
))))
3695 || gimple_assign_single_p (t
))
3696 get_constraint_for (rhsop
, &rhsc
);
3699 temp
.type
= ADDRESSOF
;
3700 temp
.var
= anything_id
;
3702 VEC_safe_push (ce_s
, heap
, rhsc
, &temp
);
3704 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, c
); j
++)
3706 struct constraint_expr
*c2
;
3709 for (k
= 0; VEC_iterate (ce_s
, rhsc
, k
, c2
); k
++)
3710 process_constraint (new_constraint (*c
, *c2
));
3715 stmt_escape_type
= is_escape_site (t
);
3716 if (stmt_escape_type
== ESCAPE_STORED_IN_GLOBAL
)
3718 gcc_assert (is_gimple_assign (t
));
3719 if (gimple_assign_rhs_code (t
) == ADDR_EXPR
)
3721 tree rhs
= gimple_assign_rhs1 (t
);
3722 tree base
= get_base_address (TREE_OPERAND (rhs
, 0));
3725 || !is_global_var (base
)))
3726 make_escape_constraint (rhs
);
3728 else if (get_gimple_rhs_class (gimple_assign_rhs_code (t
))
3729 == GIMPLE_SINGLE_RHS
)
3731 if (could_have_pointers (gimple_assign_rhs1 (t
)))
3732 make_escape_constraint (gimple_assign_rhs1 (t
));
3737 else if (stmt_escape_type
== ESCAPE_BAD_CAST
)
3739 gcc_assert (is_gimple_assign (t
));
3740 gcc_assert (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t
))
3741 || gimple_assign_rhs_code (t
) == VIEW_CONVERT_EXPR
);
3742 make_escape_constraint (gimple_assign_rhs1 (t
));
3744 else if (stmt_escape_type
== ESCAPE_TO_ASM
)
3746 unsigned i
, noutputs
;
3747 const char **oconstraints
;
3748 const char *constraint
;
3749 bool allows_mem
, allows_reg
, is_inout
;
3751 noutputs
= gimple_asm_noutputs (t
);
3752 oconstraints
= XALLOCAVEC (const char *, noutputs
);
3754 for (i
= 0; i
< noutputs
; ++i
)
3756 tree link
= gimple_asm_output_op (t
, i
);
3757 tree op
= TREE_VALUE (link
);
3759 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
3760 oconstraints
[i
] = constraint
;
3761 parse_output_constraint (&constraint
, i
, 0, 0, &allows_mem
,
3762 &allows_reg
, &is_inout
);
3764 /* A memory constraint makes the address of the operand escape. */
3765 if (!allows_reg
&& allows_mem
)
3766 make_escape_constraint (build_fold_addr_expr (op
));
3768 /* The asm may read global memory, so outputs may point to
3769 any global memory. */
3770 if (op
&& could_have_pointers (op
))
3772 VEC(ce_s
, heap
) *lhsc
= NULL
;
3773 struct constraint_expr rhsc
, *lhsp
;
3775 get_constraint_for (op
, &lhsc
);
3776 rhsc
.var
= nonlocal_id
;
3779 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); j
++)
3780 process_constraint (new_constraint (*lhsp
, rhsc
));
3781 VEC_free (ce_s
, heap
, lhsc
);
3784 for (i
= 0; i
< gimple_asm_ninputs (t
); ++i
)
3786 tree link
= gimple_asm_input_op (t
, i
);
3787 tree op
= TREE_VALUE (link
);
3789 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
3791 parse_input_constraint (&constraint
, 0, 0, noutputs
, 0, oconstraints
,
3792 &allows_mem
, &allows_reg
);
3794 /* A memory constraint makes the address of the operand escape. */
3795 if (!allows_reg
&& allows_mem
)
3796 make_escape_constraint (build_fold_addr_expr (op
));
3797 /* Strictly we'd only need the constraint to ESCAPED if
3798 the asm clobbers memory, otherwise using CALLUSED
3800 else if (op
&& could_have_pointers (op
))
3801 make_escape_constraint (op
);
3805 VEC_free (ce_s
, heap
, rhsc
);
3806 VEC_free (ce_s
, heap
, lhsc
);
3810 /* Find the first varinfo in the same variable as START that overlaps with
3811 OFFSET. Return NULL if we can't find one. */
3814 first_vi_for_offset (varinfo_t start
, unsigned HOST_WIDE_INT offset
)
3816 /* If the offset is outside of the variable, bail out. */
3817 if (offset
>= start
->fullsize
)
3820 /* If we cannot reach offset from start, lookup the first field
3821 and start from there. */
3822 if (start
->offset
> offset
)
3823 start
= lookup_vi_for_tree (start
->decl
);
3827 /* We may not find a variable in the field list with the actual
3828 offset when when we have glommed a structure to a variable.
3829 In that case, however, offset should still be within the size
3831 if (offset
>= start
->offset
3832 && offset
< (start
->offset
+ start
->size
))
3841 /* Find the first varinfo in the same variable as START that overlaps with
3842 OFFSET. If there is no such varinfo the varinfo directly preceding
3843 OFFSET is returned. */
3846 first_or_preceding_vi_for_offset (varinfo_t start
,
3847 unsigned HOST_WIDE_INT offset
)
3849 /* If we cannot reach offset from start, lookup the first field
3850 and start from there. */
3851 if (start
->offset
> offset
)
3852 start
= lookup_vi_for_tree (start
->decl
);
3854 /* We may not find a variable in the field list with the actual
3855 offset when when we have glommed a structure to a variable.
3856 In that case, however, offset should still be within the size
3858 If we got beyond the offset we look for return the field
3859 directly preceding offset which may be the last field. */
3861 && offset
>= start
->offset
3862 && !(offset
< (start
->offset
+ start
->size
)))
3863 start
= start
->next
;
3869 /* Insert the varinfo FIELD into the field list for BASE, at the front
3873 insert_into_field_list (varinfo_t base
, varinfo_t field
)
3875 varinfo_t prev
= base
;
3876 varinfo_t curr
= base
->next
;
3882 /* Insert the varinfo FIELD into the field list for BASE, ordered by
3886 insert_into_field_list_sorted (varinfo_t base
, varinfo_t field
)
3888 varinfo_t prev
= base
;
3889 varinfo_t curr
= base
->next
;
3900 if (field
->offset
<= curr
->offset
)
3905 field
->next
= prev
->next
;
3910 /* This structure is used during pushing fields onto the fieldstack
3911 to track the offset of the field, since bitpos_of_field gives it
3912 relative to its immediate containing type, and we want it relative
3913 to the ultimate containing object. */
3917 /* Offset from the base of the base containing object to this field. */
3918 HOST_WIDE_INT offset
;
3920 /* Size, in bits, of the field. */
3921 unsigned HOST_WIDE_INT size
;
3923 unsigned has_unknown_size
: 1;
3925 unsigned may_have_pointers
: 1;
3927 typedef struct fieldoff fieldoff_s
;
3929 DEF_VEC_O(fieldoff_s
);
3930 DEF_VEC_ALLOC_O(fieldoff_s
,heap
);
3932 /* qsort comparison function for two fieldoff's PA and PB */
3935 fieldoff_compare (const void *pa
, const void *pb
)
3937 const fieldoff_s
*foa
= (const fieldoff_s
*)pa
;
3938 const fieldoff_s
*fob
= (const fieldoff_s
*)pb
;
3939 unsigned HOST_WIDE_INT foasize
, fobsize
;
3941 if (foa
->offset
< fob
->offset
)
3943 else if (foa
->offset
> fob
->offset
)
3946 foasize
= foa
->size
;
3947 fobsize
= fob
->size
;
3948 if (foasize
< fobsize
)
3950 else if (foasize
> fobsize
)
3955 /* Sort a fieldstack according to the field offset and sizes. */
3957 sort_fieldstack (VEC(fieldoff_s
,heap
) *fieldstack
)
3959 qsort (VEC_address (fieldoff_s
, fieldstack
),
3960 VEC_length (fieldoff_s
, fieldstack
),
3961 sizeof (fieldoff_s
),
3965 /* Return true if V is a tree that we can have subvars for.
3966 Normally, this is any aggregate type. Also complex
3967 types which are not gimple registers can have subvars. */
3970 var_can_have_subvars (const_tree v
)
3972 /* Volatile variables should never have subvars. */
3973 if (TREE_THIS_VOLATILE (v
))
3976 /* Non decls or memory tags can never have subvars. */
3980 /* Aggregates without overlapping fields can have subvars. */
3981 if (TREE_CODE (TREE_TYPE (v
)) == RECORD_TYPE
)
3987 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
3988 the fields of TYPE onto fieldstack, recording their offsets along
3991 OFFSET is used to keep track of the offset in this entire
3992 structure, rather than just the immediately containing structure.
3993 Returns the number of fields pushed. */
3996 push_fields_onto_fieldstack (tree type
, VEC(fieldoff_s
,heap
) **fieldstack
,
3997 HOST_WIDE_INT offset
)
4002 if (TREE_CODE (type
) != RECORD_TYPE
)
4005 /* If the vector of fields is growing too big, bail out early.
4006 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4008 if (VEC_length (fieldoff_s
, *fieldstack
) > MAX_FIELDS_FOR_FIELD_SENSITIVE
)
4011 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
4012 if (TREE_CODE (field
) == FIELD_DECL
)
4016 HOST_WIDE_INT foff
= bitpos_of_field (field
);
4018 if (!var_can_have_subvars (field
)
4019 || TREE_CODE (TREE_TYPE (field
)) == QUAL_UNION_TYPE
4020 || TREE_CODE (TREE_TYPE (field
)) == UNION_TYPE
)
4022 else if (!(pushed
= push_fields_onto_fieldstack
4023 (TREE_TYPE (field
), fieldstack
, offset
+ foff
))
4024 && (DECL_SIZE (field
)
4025 && !integer_zerop (DECL_SIZE (field
))))
4026 /* Empty structures may have actual size, like in C++. So
4027 see if we didn't push any subfields and the size is
4028 nonzero, push the field onto the stack. */
4033 fieldoff_s
*pair
= NULL
;
4034 bool has_unknown_size
= false;
4036 if (!VEC_empty (fieldoff_s
, *fieldstack
))
4037 pair
= VEC_last (fieldoff_s
, *fieldstack
);
4039 if (!DECL_SIZE (field
)
4040 || !host_integerp (DECL_SIZE (field
), 1))
4041 has_unknown_size
= true;
4043 /* If adjacent fields do not contain pointers merge them. */
4045 && !pair
->may_have_pointers
4046 && !could_have_pointers (field
)
4047 && !pair
->has_unknown_size
4048 && !has_unknown_size
4049 && pair
->offset
+ (HOST_WIDE_INT
)pair
->size
== offset
+ foff
)
4051 pair
= VEC_last (fieldoff_s
, *fieldstack
);
4052 pair
->size
+= TREE_INT_CST_LOW (DECL_SIZE (field
));
4056 pair
= VEC_safe_push (fieldoff_s
, heap
, *fieldstack
, NULL
);
4057 pair
->offset
= offset
+ foff
;
4058 pair
->has_unknown_size
= has_unknown_size
;
4059 if (!has_unknown_size
)
4060 pair
->size
= TREE_INT_CST_LOW (DECL_SIZE (field
));
4063 pair
->may_have_pointers
= could_have_pointers (field
);
4074 /* Create a constraint ID = &FROM. */
4077 make_constraint_from (varinfo_t vi
, int from
)
4079 struct constraint_expr lhs
, rhs
;
4087 rhs
.type
= ADDRESSOF
;
4088 process_constraint (new_constraint (lhs
, rhs
));
4091 /* Create a constraint ID = FROM. */
4094 make_copy_constraint (varinfo_t vi
, int from
)
4096 struct constraint_expr lhs
, rhs
;
4105 process_constraint (new_constraint (lhs
, rhs
));
4108 /* Count the number of arguments DECL has, and set IS_VARARGS to true
4109 if it is a varargs function. */
4112 count_num_arguments (tree decl
, bool *is_varargs
)
4117 for (t
= TYPE_ARG_TYPES (TREE_TYPE (decl
));
4121 if (TREE_VALUE (t
) == void_type_node
)
4131 /* Creation function node for DECL, using NAME, and return the index
4132 of the variable we've created for the function. */
4135 create_function_info_for (tree decl
, const char *name
)
4137 unsigned int index
= VEC_length (varinfo_t
, varmap
);
4141 bool is_varargs
= false;
4143 /* Create the variable info. */
4145 vi
= new_var_info (decl
, index
, name
);
4149 vi
->fullsize
= count_num_arguments (decl
, &is_varargs
) + 1;
4150 insert_vi_for_tree (vi
->decl
, vi
);
4151 VEC_safe_push (varinfo_t
, heap
, varmap
, vi
);
4155 /* If it's varargs, we don't know how many arguments it has, so we
4161 vi
->is_unknown_size_var
= true;
4166 arg
= DECL_ARGUMENTS (decl
);
4168 /* Set up variables for each argument. */
4169 for (i
= 1; i
< vi
->fullsize
; i
++)
4172 const char *newname
;
4174 unsigned int newindex
;
4175 tree argdecl
= decl
;
4180 newindex
= VEC_length (varinfo_t
, varmap
);
4181 asprintf (&tempname
, "%s.arg%d", name
, i
-1);
4182 newname
= ggc_strdup (tempname
);
4185 argvi
= new_var_info (argdecl
, newindex
, newname
);
4186 argvi
->decl
= argdecl
;
4187 VEC_safe_push (varinfo_t
, heap
, varmap
, argvi
);
4190 argvi
->is_full_var
= true;
4191 argvi
->fullsize
= vi
->fullsize
;
4192 insert_into_field_list_sorted (vi
, argvi
);
4193 stats
.total_vars
++;
4196 insert_vi_for_tree (arg
, argvi
);
4197 arg
= TREE_CHAIN (arg
);
4201 /* Create a variable for the return var. */
4202 if (DECL_RESULT (decl
) != NULL
4203 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl
))))
4206 const char *newname
;
4208 unsigned int newindex
;
4209 tree resultdecl
= decl
;
4213 if (DECL_RESULT (decl
))
4214 resultdecl
= DECL_RESULT (decl
);
4216 newindex
= VEC_length (varinfo_t
, varmap
);
4217 asprintf (&tempname
, "%s.result", name
);
4218 newname
= ggc_strdup (tempname
);
4221 resultvi
= new_var_info (resultdecl
, newindex
, newname
);
4222 resultvi
->decl
= resultdecl
;
4223 VEC_safe_push (varinfo_t
, heap
, varmap
, resultvi
);
4224 resultvi
->offset
= i
;
4226 resultvi
->fullsize
= vi
->fullsize
;
4227 resultvi
->is_full_var
= true;
4228 insert_into_field_list_sorted (vi
, resultvi
);
4229 stats
.total_vars
++;
4230 if (DECL_RESULT (decl
))
4231 insert_vi_for_tree (DECL_RESULT (decl
), resultvi
);
4237 /* Return true if FIELDSTACK contains fields that overlap.
4238 FIELDSTACK is assumed to be sorted by offset. */
4241 check_for_overlaps (VEC (fieldoff_s
,heap
) *fieldstack
)
4243 fieldoff_s
*fo
= NULL
;
4245 HOST_WIDE_INT lastoffset
= -1;
4247 for (i
= 0; VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
); i
++)
4249 if (fo
->offset
== lastoffset
)
4251 lastoffset
= fo
->offset
;
4256 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
4257 This will also create any varinfo structures necessary for fields
4261 create_variable_info_for (tree decl
, const char *name
)
4263 unsigned int index
= VEC_length (varinfo_t
, varmap
);
4265 tree decl_type
= TREE_TYPE (decl
);
4266 tree declsize
= DECL_P (decl
) ? DECL_SIZE (decl
) : TYPE_SIZE (decl_type
);
4267 bool is_global
= DECL_P (decl
) ? is_global_var (decl
) : false;
4268 VEC (fieldoff_s
,heap
) *fieldstack
= NULL
;
4270 if (TREE_CODE (decl
) == FUNCTION_DECL
&& in_ipa_mode
)
4271 return create_function_info_for (decl
, name
);
4273 if (var_can_have_subvars (decl
) && use_field_sensitive
4275 || var_ann (decl
)->noalias_state
== 0)
4277 || !var_ann (decl
)->is_heapvar
))
4278 push_fields_onto_fieldstack (decl_type
, &fieldstack
, 0);
4280 /* If the variable doesn't have subvars, we may end up needing to
4281 sort the field list and create fake variables for all the
4283 vi
= new_var_info (decl
, index
, name
);
4286 vi
->may_have_pointers
= could_have_pointers (decl
);
4288 || !host_integerp (declsize
, 1))
4290 vi
->is_unknown_size_var
= true;
4296 vi
->fullsize
= TREE_INT_CST_LOW (declsize
);
4297 vi
->size
= vi
->fullsize
;
4300 insert_vi_for_tree (vi
->decl
, vi
);
4301 VEC_safe_push (varinfo_t
, heap
, varmap
, vi
);
4302 if (is_global
&& (!flag_whole_program
|| !in_ipa_mode
)
4303 && vi
->may_have_pointers
)
4306 && var_ann (decl
)->noalias_state
== NO_ALIAS_ANYTHING
)
4307 make_constraint_from (vi
, vi
->id
);
4309 make_copy_constraint (vi
, nonlocal_id
);
4313 if (use_field_sensitive
4314 && !vi
->is_unknown_size_var
4315 && var_can_have_subvars (decl
)
4316 && VEC_length (fieldoff_s
, fieldstack
) > 1
4317 && VEC_length (fieldoff_s
, fieldstack
) <= MAX_FIELDS_FOR_FIELD_SENSITIVE
)
4319 unsigned int newindex
= VEC_length (varinfo_t
, varmap
);
4320 fieldoff_s
*fo
= NULL
;
4321 bool notokay
= false;
4324 for (i
= 0; !notokay
&& VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
); i
++)
4326 if (fo
->has_unknown_size
4334 /* We can't sort them if we have a field with a variable sized type,
4335 which will make notokay = true. In that case, we are going to return
4336 without creating varinfos for the fields anyway, so sorting them is a
4340 sort_fieldstack (fieldstack
);
4341 /* Due to some C++ FE issues, like PR 22488, we might end up
4342 what appear to be overlapping fields even though they,
4343 in reality, do not overlap. Until the C++ FE is fixed,
4344 we will simply disable field-sensitivity for these cases. */
4345 notokay
= check_for_overlaps (fieldstack
);
4349 if (VEC_length (fieldoff_s
, fieldstack
) != 0)
4350 fo
= VEC_index (fieldoff_s
, fieldstack
, 0);
4352 if (fo
== NULL
|| notokay
)
4354 vi
->is_unknown_size_var
= 1;
4357 vi
->is_full_var
= true;
4358 VEC_free (fieldoff_s
, heap
, fieldstack
);
4362 vi
->size
= fo
->size
;
4363 vi
->offset
= fo
->offset
;
4364 vi
->may_have_pointers
= fo
->may_have_pointers
;
4365 for (i
= VEC_length (fieldoff_s
, fieldstack
) - 1;
4366 i
>= 1 && VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
);
4370 const char *newname
= "NULL";
4373 newindex
= VEC_length (varinfo_t
, varmap
);
4376 asprintf (&tempname
, "%s." HOST_WIDE_INT_PRINT_DEC
4377 "+" HOST_WIDE_INT_PRINT_DEC
,
4378 vi
->name
, fo
->offset
, fo
->size
);
4379 newname
= ggc_strdup (tempname
);
4382 newvi
= new_var_info (decl
, newindex
, newname
);
4383 newvi
->offset
= fo
->offset
;
4384 newvi
->size
= fo
->size
;
4385 newvi
->fullsize
= vi
->fullsize
;
4386 newvi
->may_have_pointers
= fo
->may_have_pointers
;
4387 insert_into_field_list (vi
, newvi
);
4388 VEC_safe_push (varinfo_t
, heap
, varmap
, newvi
);
4389 if (is_global
&& (!flag_whole_program
|| !in_ipa_mode
)
4390 && newvi
->may_have_pointers
)
4391 make_copy_constraint (newvi
, nonlocal_id
);
4397 vi
->is_full_var
= true;
4399 VEC_free (fieldoff_s
, heap
, fieldstack
);
4404 /* Print out the points-to solution for VAR to FILE. */
4407 dump_solution_for_var (FILE *file
, unsigned int var
)
4409 varinfo_t vi
= get_varinfo (var
);
4413 if (find (var
) != var
)
4415 varinfo_t vipt
= get_varinfo (find (var
));
4416 fprintf (file
, "%s = same as %s\n", vi
->name
, vipt
->name
);
4420 fprintf (file
, "%s = { ", vi
->name
);
4421 EXECUTE_IF_SET_IN_BITMAP (vi
->solution
, 0, i
, bi
)
4423 fprintf (file
, "%s ", get_varinfo (i
)->name
);
4425 fprintf (file
, "}\n");
4429 /* Print the points-to solution for VAR to stdout. */
4432 debug_solution_for_var (unsigned int var
)
4434 dump_solution_for_var (stdout
, var
);
4437 /* Create varinfo structures for all of the variables in the
4438 function for intraprocedural mode. */
4441 intra_create_variable_infos (void)
4444 struct constraint_expr lhs
, rhs
;
4446 /* For each incoming pointer argument arg, create the constraint ARG
4447 = NONLOCAL or a dummy variable if flag_argument_noalias is set. */
4448 for (t
= DECL_ARGUMENTS (current_function_decl
); t
; t
= TREE_CHAIN (t
))
4452 if (!could_have_pointers (t
))
4455 /* If flag_argument_noalias is set, then function pointer
4456 arguments are guaranteed not to point to each other. In that
4457 case, create an artificial variable PARM_NOALIAS and the
4458 constraint ARG = &PARM_NOALIAS. */
4459 if (POINTER_TYPE_P (TREE_TYPE (t
)) && flag_argument_noalias
> 0)
4462 tree heapvar
= heapvar_lookup (t
);
4466 lhs
.var
= get_vi_for_tree (t
)->id
;
4468 if (heapvar
== NULL_TREE
)
4471 heapvar
= create_tmp_var_raw (ptr_type_node
,
4473 DECL_EXTERNAL (heapvar
) = 1;
4474 if (gimple_referenced_vars (cfun
))
4475 add_referenced_var (heapvar
);
4477 heapvar_insert (t
, heapvar
);
4479 ann
= get_var_ann (heapvar
);
4480 ann
->is_heapvar
= 1;
4481 if (flag_argument_noalias
== 1)
4482 ann
->noalias_state
= NO_ALIAS
;
4483 else if (flag_argument_noalias
== 2)
4484 ann
->noalias_state
= NO_ALIAS_GLOBAL
;
4485 else if (flag_argument_noalias
== 3)
4486 ann
->noalias_state
= NO_ALIAS_ANYTHING
;
4491 vi
= get_vi_for_tree (heapvar
);
4492 vi
->is_artificial_var
= 1;
4493 vi
->is_heap_var
= 1;
4494 vi
->is_unknown_size_var
= true;
4498 rhs
.type
= ADDRESSOF
;
4500 for (p
= get_varinfo (lhs
.var
); p
; p
= p
->next
)
4502 struct constraint_expr temp
= lhs
;
4504 process_constraint (new_constraint (temp
, rhs
));
4509 varinfo_t arg_vi
= get_vi_for_tree (t
);
4511 for (p
= arg_vi
; p
; p
= p
->next
)
4512 make_constraint_from (p
, nonlocal_id
);
4516 /* Add a constraint for a result decl that is passed by reference. */
4517 if (DECL_RESULT (cfun
->decl
)
4518 && DECL_BY_REFERENCE (DECL_RESULT (cfun
->decl
)))
4520 varinfo_t p
, result_vi
= get_vi_for_tree (DECL_RESULT (cfun
->decl
));
4522 for (p
= result_vi
; p
; p
= p
->next
)
4523 make_constraint_from (p
, nonlocal_id
);
4526 /* Add a constraint for the incoming static chain parameter. */
4527 if (cfun
->static_chain_decl
!= NULL_TREE
)
4529 varinfo_t p
, chain_vi
= get_vi_for_tree (cfun
->static_chain_decl
);
4531 for (p
= chain_vi
; p
; p
= p
->next
)
4532 make_constraint_from (p
, nonlocal_id
);
4536 /* Structure used to put solution bitmaps in a hashtable so they can
4537 be shared among variables with the same points-to set. */
4539 typedef struct shared_bitmap_info
4543 } *shared_bitmap_info_t
;
4544 typedef const struct shared_bitmap_info
*const_shared_bitmap_info_t
;
4546 static htab_t shared_bitmap_table
;
4548 /* Hash function for a shared_bitmap_info_t */
4551 shared_bitmap_hash (const void *p
)
4553 const_shared_bitmap_info_t
const bi
= (const_shared_bitmap_info_t
) p
;
4554 return bi
->hashcode
;
4557 /* Equality function for two shared_bitmap_info_t's. */
4560 shared_bitmap_eq (const void *p1
, const void *p2
)
4562 const_shared_bitmap_info_t
const sbi1
= (const_shared_bitmap_info_t
) p1
;
4563 const_shared_bitmap_info_t
const sbi2
= (const_shared_bitmap_info_t
) p2
;
4564 return bitmap_equal_p (sbi1
->pt_vars
, sbi2
->pt_vars
);
4567 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
4568 existing instance if there is one, NULL otherwise. */
4571 shared_bitmap_lookup (bitmap pt_vars
)
4574 struct shared_bitmap_info sbi
;
4576 sbi
.pt_vars
= pt_vars
;
4577 sbi
.hashcode
= bitmap_hash (pt_vars
);
4579 slot
= htab_find_slot_with_hash (shared_bitmap_table
, &sbi
,
4580 sbi
.hashcode
, NO_INSERT
);
4584 return ((shared_bitmap_info_t
) *slot
)->pt_vars
;
4588 /* Add a bitmap to the shared bitmap hashtable. */
4591 shared_bitmap_add (bitmap pt_vars
)
4594 shared_bitmap_info_t sbi
= XNEW (struct shared_bitmap_info
);
4596 sbi
->pt_vars
= pt_vars
;
4597 sbi
->hashcode
= bitmap_hash (pt_vars
);
4599 slot
= htab_find_slot_with_hash (shared_bitmap_table
, sbi
,
4600 sbi
->hashcode
, INSERT
);
4601 gcc_assert (!*slot
);
4602 *slot
= (void *) sbi
;
4606 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
4609 set_uids_in_ptset (bitmap into
, bitmap from
, struct pt_solution
*pt
)
4614 EXECUTE_IF_SET_IN_BITMAP (from
, 0, i
, bi
)
4616 varinfo_t vi
= get_varinfo (i
);
4618 /* The only artificial variables that are allowed in a may-alias
4619 set are heap variables. */
4620 if (vi
->is_artificial_var
&& !vi
->is_heap_var
)
4623 if (TREE_CODE (vi
->decl
) == VAR_DECL
4624 || TREE_CODE (vi
->decl
) == PARM_DECL
4625 || TREE_CODE (vi
->decl
) == RESULT_DECL
)
4627 /* Add the decl to the points-to set. Note that the points-to
4628 set contains global variables. */
4629 bitmap_set_bit (into
, DECL_UID (vi
->decl
));
4630 if (is_global_var (vi
->decl
))
4631 pt
->vars_contains_global
= true;
4637 static bool have_alias_info
= false;
4639 /* Compute the points-to solution *PT for the variable VI. */
4642 find_what_var_points_to (varinfo_t vi
, struct pt_solution
*pt
)
4646 bitmap finished_solution
;
4648 tree ptr
= vi
->decl
;
4650 memset (pt
, 0, sizeof (struct pt_solution
));
4652 /* This variable may have been collapsed, let's get the real
4654 vi
= get_varinfo (find (vi
->id
));
4656 /* Translate artificial variables into SSA_NAME_PTR_INFO
4658 EXECUTE_IF_SET_IN_BITMAP (vi
->solution
, 0, i
, bi
)
4660 varinfo_t vi
= get_varinfo (i
);
4662 if (vi
->is_artificial_var
)
4664 if (vi
->id
== nothing_id
)
4666 else if (vi
->id
== escaped_id
)
4668 else if (vi
->id
== callused_id
)
4670 else if (vi
->id
== nonlocal_id
)
4672 else if (vi
->is_heap_var
)
4673 /* We represent heapvars in the points-to set properly. */
4675 else if (vi
->id
== anything_id
4676 || vi
->id
== readonly_id
4677 || vi
->id
== integer_id
)
4682 /* Instead of doing extra work, simply do not create
4683 elaborate points-to information for pt_anything pointers. */
4687 /* Share the final set of variables when possible. */
4688 finished_solution
= BITMAP_GGC_ALLOC ();
4689 stats
.points_to_sets_created
++;
4691 if (TREE_CODE (ptr
) == SSA_NAME
)
4692 ptr
= SSA_NAME_VAR (ptr
);
4694 set_uids_in_ptset (finished_solution
, vi
->solution
, pt
);
4695 result
= shared_bitmap_lookup (finished_solution
);
4698 shared_bitmap_add (finished_solution
);
4699 pt
->vars
= finished_solution
;
4704 bitmap_clear (finished_solution
);
4708 /* Given a pointer variable P, fill in its points-to set. */
4711 find_what_p_points_to (tree p
)
4713 struct ptr_info_def
*pi
;
4717 /* For parameters, get at the points-to set for the actual parm
4719 if (TREE_CODE (p
) == SSA_NAME
4720 && TREE_CODE (SSA_NAME_VAR (p
)) == PARM_DECL
4721 && SSA_NAME_IS_DEFAULT_DEF (p
))
4722 lookup_p
= SSA_NAME_VAR (p
);
4724 vi
= lookup_vi_for_tree (lookup_p
);
4728 pi
= get_ptr_info (p
);
4729 find_what_var_points_to (vi
, &pi
->pt
);
4733 /* Query statistics for points-to solutions. */
4736 unsigned HOST_WIDE_INT pt_solution_includes_may_alias
;
4737 unsigned HOST_WIDE_INT pt_solution_includes_no_alias
;
4738 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias
;
4739 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias
;
4743 dump_pta_stats (FILE *s
)
4745 fprintf (s
, "\nPTA query stats:\n");
4746 fprintf (s
, " pt_solution_includes: "
4747 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
4748 HOST_WIDE_INT_PRINT_DEC
" queries\n",
4749 pta_stats
.pt_solution_includes_no_alias
,
4750 pta_stats
.pt_solution_includes_no_alias
4751 + pta_stats
.pt_solution_includes_may_alias
);
4752 fprintf (s
, " pt_solutions_intersect: "
4753 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
4754 HOST_WIDE_INT_PRINT_DEC
" queries\n",
4755 pta_stats
.pt_solutions_intersect_no_alias
,
4756 pta_stats
.pt_solutions_intersect_no_alias
4757 + pta_stats
.pt_solutions_intersect_may_alias
);
4761 /* Reset the points-to solution *PT to a conservative default
4762 (point to anything). */
4765 pt_solution_reset (struct pt_solution
*pt
)
4767 memset (pt
, 0, sizeof (struct pt_solution
));
4768 pt
->anything
= true;
4771 /* Return true if the points-to solution *PT is empty. */
4774 pt_solution_empty_p (struct pt_solution
*pt
)
4781 && !bitmap_empty_p (pt
->vars
))
4784 /* If the solution includes ESCAPED, check if that is empty. */
4786 && !pt_solution_empty_p (&cfun
->gimple_df
->escaped
))
4792 /* Return true if the points-to solution *PT includes global memory. */
4795 pt_solution_includes_global (struct pt_solution
*pt
)
4799 || pt
->vars_contains_global
)
4803 return pt_solution_includes_global (&cfun
->gimple_df
->escaped
);
4808 /* Return true if the points-to solution *PT includes the variable
4809 declaration DECL. */
4812 pt_solution_includes_1 (struct pt_solution
*pt
, const_tree decl
)
4818 && is_global_var (decl
))
4822 && bitmap_bit_p (pt
->vars
, DECL_UID (decl
)))
4825 /* If the solution includes ESCAPED, check it. */
4827 && pt_solution_includes_1 (&cfun
->gimple_df
->escaped
, decl
))
4834 pt_solution_includes (struct pt_solution
*pt
, const_tree decl
)
4836 bool res
= pt_solution_includes_1 (pt
, decl
);
4838 ++pta_stats
.pt_solution_includes_may_alias
;
4840 ++pta_stats
.pt_solution_includes_no_alias
;
4844 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
4848 pt_solutions_intersect_1 (struct pt_solution
*pt1
, struct pt_solution
*pt2
)
4850 if (pt1
->anything
|| pt2
->anything
)
4853 /* If either points to unknown global memory and the other points to
4854 any global memory they alias. */
4857 || pt2
->vars_contains_global
))
4859 && pt1
->vars_contains_global
))
4862 /* Check the escaped solution if required. */
4863 if ((pt1
->escaped
|| pt2
->escaped
)
4864 && !pt_solution_empty_p (&cfun
->gimple_df
->escaped
))
4866 /* If both point to escaped memory and that solution
4867 is not empty they alias. */
4868 if (pt1
->escaped
&& pt2
->escaped
)
4871 /* If either points to escaped memory see if the escaped solution
4872 intersects with the other. */
4874 && pt_solutions_intersect_1 (&cfun
->gimple_df
->escaped
, pt2
))
4876 && pt_solutions_intersect_1 (&cfun
->gimple_df
->escaped
, pt1
)))
4880 /* Now both pointers alias if their points-to solution intersects. */
4883 && bitmap_intersect_p (pt1
->vars
, pt2
->vars
));
4887 pt_solutions_intersect (struct pt_solution
*pt1
, struct pt_solution
*pt2
)
4889 bool res
= pt_solutions_intersect_1 (pt1
, pt2
);
4891 ++pta_stats
.pt_solutions_intersect_may_alias
;
4893 ++pta_stats
.pt_solutions_intersect_no_alias
;
4898 /* Dump points-to information to OUTFILE. */
4901 dump_sa_points_to_info (FILE *outfile
)
4905 fprintf (outfile
, "\nPoints-to sets\n\n");
4907 if (dump_flags
& TDF_STATS
)
4909 fprintf (outfile
, "Stats:\n");
4910 fprintf (outfile
, "Total vars: %d\n", stats
.total_vars
);
4911 fprintf (outfile
, "Non-pointer vars: %d\n",
4912 stats
.nonpointer_vars
);
4913 fprintf (outfile
, "Statically unified vars: %d\n",
4914 stats
.unified_vars_static
);
4915 fprintf (outfile
, "Dynamically unified vars: %d\n",
4916 stats
.unified_vars_dynamic
);
4917 fprintf (outfile
, "Iterations: %d\n", stats
.iterations
);
4918 fprintf (outfile
, "Number of edges: %d\n", stats
.num_edges
);
4919 fprintf (outfile
, "Number of implicit edges: %d\n",
4920 stats
.num_implicit_edges
);
4923 for (i
= 0; i
< VEC_length (varinfo_t
, varmap
); i
++)
4924 dump_solution_for_var (outfile
, i
);
4928 /* Debug points-to information to stderr. */
4931 debug_sa_points_to_info (void)
4933 dump_sa_points_to_info (stderr
);
4937 /* Initialize the always-existing constraint variables for NULL
4938 ANYTHING, READONLY, and INTEGER */
4941 init_base_vars (void)
4943 struct constraint_expr lhs
, rhs
;
4945 /* Create the NULL variable, used to represent that a variable points
4947 nothing_tree
= create_tmp_var_raw (void_type_node
, "NULL");
4948 var_nothing
= new_var_info (nothing_tree
, nothing_id
, "NULL");
4949 insert_vi_for_tree (nothing_tree
, var_nothing
);
4950 var_nothing
->is_artificial_var
= 1;
4951 var_nothing
->offset
= 0;
4952 var_nothing
->size
= ~0;
4953 var_nothing
->fullsize
= ~0;
4954 var_nothing
->is_special_var
= 1;
4955 VEC_safe_push (varinfo_t
, heap
, varmap
, var_nothing
);
4957 /* Create the ANYTHING variable, used to represent that a variable
4958 points to some unknown piece of memory. */
4959 anything_tree
= create_tmp_var_raw (ptr_type_node
, "ANYTHING");
4960 var_anything
= new_var_info (anything_tree
, anything_id
, "ANYTHING");
4961 insert_vi_for_tree (anything_tree
, var_anything
);
4962 var_anything
->is_artificial_var
= 1;
4963 var_anything
->size
= ~0;
4964 var_anything
->offset
= 0;
4965 var_anything
->next
= NULL
;
4966 var_anything
->fullsize
= ~0;
4967 var_anything
->is_special_var
= 1;
4969 /* Anything points to anything. This makes deref constraints just
4970 work in the presence of linked list and other p = *p type loops,
4971 by saying that *ANYTHING = ANYTHING. */
4972 VEC_safe_push (varinfo_t
, heap
, varmap
, var_anything
);
4974 lhs
.var
= anything_id
;
4976 rhs
.type
= ADDRESSOF
;
4977 rhs
.var
= anything_id
;
4980 /* This specifically does not use process_constraint because
4981 process_constraint ignores all anything = anything constraints, since all
4982 but this one are redundant. */
4983 VEC_safe_push (constraint_t
, heap
, constraints
, new_constraint (lhs
, rhs
));
4985 /* Create the READONLY variable, used to represent that a variable
4986 points to readonly memory. */
4987 readonly_tree
= create_tmp_var_raw (ptr_type_node
, "READONLY");
4988 var_readonly
= new_var_info (readonly_tree
, readonly_id
, "READONLY");
4989 var_readonly
->is_artificial_var
= 1;
4990 var_readonly
->offset
= 0;
4991 var_readonly
->size
= ~0;
4992 var_readonly
->fullsize
= ~0;
4993 var_readonly
->next
= NULL
;
4994 var_readonly
->is_special_var
= 1;
4995 insert_vi_for_tree (readonly_tree
, var_readonly
);
4996 VEC_safe_push (varinfo_t
, heap
, varmap
, var_readonly
);
4998 /* readonly memory points to anything, in order to make deref
4999 easier. In reality, it points to anything the particular
5000 readonly variable can point to, but we don't track this
5003 lhs
.var
= readonly_id
;
5005 rhs
.type
= ADDRESSOF
;
5006 rhs
.var
= readonly_id
; /* FIXME */
5008 process_constraint (new_constraint (lhs
, rhs
));
5010 /* Create the ESCAPED variable, used to represent the set of escaped
5012 escaped_tree
= create_tmp_var_raw (ptr_type_node
, "ESCAPED");
5013 var_escaped
= new_var_info (escaped_tree
, escaped_id
, "ESCAPED");
5014 insert_vi_for_tree (escaped_tree
, var_escaped
);
5015 var_escaped
->is_artificial_var
= 1;
5016 var_escaped
->offset
= 0;
5017 var_escaped
->size
= ~0;
5018 var_escaped
->fullsize
= ~0;
5019 var_escaped
->is_special_var
= 0;
5020 VEC_safe_push (varinfo_t
, heap
, varmap
, var_escaped
);
5021 gcc_assert (VEC_index (varinfo_t
, varmap
, 3) == var_escaped
);
5023 /* Create the NONLOCAL variable, used to represent the set of nonlocal
5025 nonlocal_tree
= create_tmp_var_raw (ptr_type_node
, "NONLOCAL");
5026 var_nonlocal
= new_var_info (nonlocal_tree
, nonlocal_id
, "NONLOCAL");
5027 insert_vi_for_tree (nonlocal_tree
, var_nonlocal
);
5028 var_nonlocal
->is_artificial_var
= 1;
5029 var_nonlocal
->offset
= 0;
5030 var_nonlocal
->size
= ~0;
5031 var_nonlocal
->fullsize
= ~0;
5032 var_nonlocal
->is_special_var
= 1;
5033 VEC_safe_push (varinfo_t
, heap
, varmap
, var_nonlocal
);
5035 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
5037 lhs
.var
= escaped_id
;
5040 rhs
.var
= escaped_id
;
5042 process_constraint (new_constraint (lhs
, rhs
));
5044 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
5045 whole variable escapes. */
5047 lhs
.var
= escaped_id
;
5050 rhs
.var
= escaped_id
;
5051 rhs
.offset
= UNKNOWN_OFFSET
;
5052 process_constraint (new_constraint (lhs
, rhs
));
5054 /* *ESCAPED = NONLOCAL. This is true because we have to assume
5055 everything pointed to by escaped points to what global memory can
5058 lhs
.var
= escaped_id
;
5061 rhs
.var
= nonlocal_id
;
5063 process_constraint (new_constraint (lhs
, rhs
));
5065 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
5066 global memory may point to global memory and escaped memory. */
5068 lhs
.var
= nonlocal_id
;
5070 rhs
.type
= ADDRESSOF
;
5071 rhs
.var
= nonlocal_id
;
5073 process_constraint (new_constraint (lhs
, rhs
));
5074 rhs
.type
= ADDRESSOF
;
5075 rhs
.var
= escaped_id
;
5077 process_constraint (new_constraint (lhs
, rhs
));
5079 /* Create the CALLUSED variable, used to represent the set of call-used
5081 callused_tree
= create_tmp_var_raw (ptr_type_node
, "CALLUSED");
5082 var_callused
= new_var_info (callused_tree
, callused_id
, "CALLUSED");
5083 insert_vi_for_tree (callused_tree
, var_callused
);
5084 var_callused
->is_artificial_var
= 1;
5085 var_callused
->offset
= 0;
5086 var_callused
->size
= ~0;
5087 var_callused
->fullsize
= ~0;
5088 var_callused
->is_special_var
= 0;
5089 VEC_safe_push (varinfo_t
, heap
, varmap
, var_callused
);
5091 /* CALLUSED = *CALLUSED, because call-used is may-deref'd at calls, etc. */
5093 lhs
.var
= callused_id
;
5096 rhs
.var
= callused_id
;
5098 process_constraint (new_constraint (lhs
, rhs
));
5100 /* CALLUSED = CALLUSED + UNKNOWN, because if a sub-field is call-used the
5101 whole variable is call-used. */
5103 lhs
.var
= callused_id
;
5106 rhs
.var
= callused_id
;
5107 rhs
.offset
= UNKNOWN_OFFSET
;
5108 process_constraint (new_constraint (lhs
, rhs
));
5110 /* Create the STOREDANYTHING variable, used to represent the set of
5111 variables stored to *ANYTHING. */
5112 storedanything_tree
= create_tmp_var_raw (ptr_type_node
, "STOREDANYTHING");
5113 var_storedanything
= new_var_info (storedanything_tree
, storedanything_id
,
5115 insert_vi_for_tree (storedanything_tree
, var_storedanything
);
5116 var_storedanything
->is_artificial_var
= 1;
5117 var_storedanything
->offset
= 0;
5118 var_storedanything
->size
= ~0;
5119 var_storedanything
->fullsize
= ~0;
5120 var_storedanything
->is_special_var
= 0;
5121 VEC_safe_push (varinfo_t
, heap
, varmap
, var_storedanything
);
5123 /* Create the INTEGER variable, used to represent that a variable points
5124 to what an INTEGER "points to". */
5125 integer_tree
= create_tmp_var_raw (ptr_type_node
, "INTEGER");
5126 var_integer
= new_var_info (integer_tree
, integer_id
, "INTEGER");
5127 insert_vi_for_tree (integer_tree
, var_integer
);
5128 var_integer
->is_artificial_var
= 1;
5129 var_integer
->size
= ~0;
5130 var_integer
->fullsize
= ~0;
5131 var_integer
->offset
= 0;
5132 var_integer
->next
= NULL
;
5133 var_integer
->is_special_var
= 1;
5134 VEC_safe_push (varinfo_t
, heap
, varmap
, var_integer
);
5136 /* INTEGER = ANYTHING, because we don't know where a dereference of
5137 a random integer will point to. */
5139 lhs
.var
= integer_id
;
5141 rhs
.type
= ADDRESSOF
;
5142 rhs
.var
= anything_id
;
5144 process_constraint (new_constraint (lhs
, rhs
));
5147 /* Initialize things necessary to perform PTA */
5150 init_alias_vars (void)
5152 use_field_sensitive
= (MAX_FIELDS_FOR_FIELD_SENSITIVE
> 1);
5154 bitmap_obstack_initialize (&pta_obstack
);
5155 bitmap_obstack_initialize (&oldpta_obstack
);
5156 bitmap_obstack_initialize (&predbitmap_obstack
);
5158 constraint_pool
= create_alloc_pool ("Constraint pool",
5159 sizeof (struct constraint
), 30);
5160 variable_info_pool
= create_alloc_pool ("Variable info pool",
5161 sizeof (struct variable_info
), 30);
5162 constraints
= VEC_alloc (constraint_t
, heap
, 8);
5163 varmap
= VEC_alloc (varinfo_t
, heap
, 8);
5164 vi_for_tree
= pointer_map_create ();
5166 memset (&stats
, 0, sizeof (stats
));
5167 shared_bitmap_table
= htab_create (511, shared_bitmap_hash
,
5168 shared_bitmap_eq
, free
);
5172 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
5173 predecessor edges. */
5176 remove_preds_and_fake_succs (constraint_graph_t graph
)
5180 /* Clear the implicit ref and address nodes from the successor
5182 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
5184 if (graph
->succs
[i
])
5185 bitmap_clear_range (graph
->succs
[i
], FIRST_REF_NODE
,
5186 FIRST_REF_NODE
* 2);
5189 /* Free the successor list for the non-ref nodes. */
5190 for (i
= FIRST_REF_NODE
; i
< graph
->size
; i
++)
5192 if (graph
->succs
[i
])
5193 BITMAP_FREE (graph
->succs
[i
]);
5196 /* Now reallocate the size of the successor list as, and blow away
5197 the predecessor bitmaps. */
5198 graph
->size
= VEC_length (varinfo_t
, varmap
);
5199 graph
->succs
= XRESIZEVEC (bitmap
, graph
->succs
, graph
->size
);
5201 free (graph
->implicit_preds
);
5202 graph
->implicit_preds
= NULL
;
5203 free (graph
->preds
);
5204 graph
->preds
= NULL
;
5205 bitmap_obstack_release (&predbitmap_obstack
);
5208 /* Initialize the heapvar for statement mapping. */
5211 init_alias_heapvars (void)
5213 if (!heapvar_for_stmt
)
5214 heapvar_for_stmt
= htab_create_ggc (11, tree_map_hash
, tree_map_eq
,
5218 /* Delete the heapvar for statement mapping. */
5221 delete_alias_heapvars (void)
5223 if (heapvar_for_stmt
)
5224 htab_delete (heapvar_for_stmt
);
5225 heapvar_for_stmt
= NULL
;
5228 /* Create points-to sets for the current function. See the comments
5229 at the start of the file for an algorithmic overview. */
5232 compute_points_to_sets (void)
5234 struct scc_info
*si
;
5238 timevar_push (TV_TREE_PTA
);
5241 init_alias_heapvars ();
5243 intra_create_variable_infos ();
5245 /* Now walk all statements and derive aliases. */
5248 gimple_stmt_iterator gsi
;
5250 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5252 gimple phi
= gsi_stmt (gsi
);
5254 if (is_gimple_reg (gimple_phi_result (phi
)))
5255 find_func_aliases (phi
);
5258 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5260 gimple stmt
= gsi_stmt (gsi
);
5262 find_func_aliases (stmt
);
5268 fprintf (dump_file
, "Points-to analysis\n\nConstraints:\n\n");
5269 dump_constraints (dump_file
);
5274 "\nCollapsing static cycles and doing variable "
5277 init_graph (VEC_length (varinfo_t
, varmap
) * 2);
5280 fprintf (dump_file
, "Building predecessor graph\n");
5281 build_pred_graph ();
5284 fprintf (dump_file
, "Detecting pointer and location "
5286 si
= perform_var_substitution (graph
);
5289 fprintf (dump_file
, "Rewriting constraints and unifying "
5291 rewrite_constraints (graph
, si
);
5293 build_succ_graph ();
5294 free_var_substitution_info (si
);
5296 if (dump_file
&& (dump_flags
& TDF_GRAPH
))
5297 dump_constraint_graph (dump_file
);
5299 move_complex_constraints (graph
);
5302 fprintf (dump_file
, "Uniting pointer but not location equivalent "
5304 unite_pointer_equivalences (graph
);
5307 fprintf (dump_file
, "Finding indirect cycles\n");
5308 find_indirect_cycles (graph
);
5310 /* Implicit nodes and predecessors are no longer necessary at this
5312 remove_preds_and_fake_succs (graph
);
5315 fprintf (dump_file
, "Solving graph\n");
5317 solve_graph (graph
);
5320 dump_sa_points_to_info (dump_file
);
5322 /* Compute the points-to sets for ESCAPED and CALLUSED used for
5323 call-clobber analysis. */
5324 find_what_var_points_to (var_escaped
, &cfun
->gimple_df
->escaped
);
5325 find_what_var_points_to (var_callused
, &cfun
->gimple_df
->callused
);
5327 /* Make sure the ESCAPED solution (which is used as placeholder in
5328 other solutions) does not reference itself. This simplifies
5329 points-to solution queries. */
5330 cfun
->gimple_df
->escaped
.escaped
= 0;
5332 /* Compute the points-to sets for pointer SSA_NAMEs. */
5333 for (i
= 0; i
< num_ssa_names
; ++i
)
5335 tree ptr
= ssa_name (i
);
5337 && POINTER_TYPE_P (TREE_TYPE (ptr
)))
5338 find_what_p_points_to (ptr
);
5341 timevar_pop (TV_TREE_PTA
);
5343 have_alias_info
= true;
5347 /* Delete created points-to sets. */
5350 delete_points_to_sets (void)
5354 htab_delete (shared_bitmap_table
);
5355 if (dump_file
&& (dump_flags
& TDF_STATS
))
5356 fprintf (dump_file
, "Points to sets created:%d\n",
5357 stats
.points_to_sets_created
);
5359 pointer_map_destroy (vi_for_tree
);
5360 bitmap_obstack_release (&pta_obstack
);
5361 VEC_free (constraint_t
, heap
, constraints
);
5363 for (i
= 0; i
< graph
->size
; i
++)
5364 VEC_free (constraint_t
, heap
, graph
->complex[i
]);
5365 free (graph
->complex);
5368 free (graph
->succs
);
5370 free (graph
->pe_rep
);
5371 free (graph
->indirect_cycles
);
5374 VEC_free (varinfo_t
, heap
, varmap
);
5375 free_alloc_pool (variable_info_pool
);
5376 free_alloc_pool (constraint_pool
);
5377 have_alias_info
= false;
5381 /* Compute points-to information for every SSA_NAME pointer in the
5382 current function and compute the transitive closure of escaped
5383 variables to re-initialize the call-clobber states of local variables. */
5386 compute_may_aliases (void)
5388 /* For each pointer P_i, determine the sets of variables that P_i may
5389 point-to. Compute the reachability set of escaped and call-used
5391 compute_points_to_sets ();
5393 /* Debugging dumps. */
5396 dump_alias_info (dump_file
);
5398 if (dump_flags
& TDF_DETAILS
)
5399 dump_referenced_vars (dump_file
);
5402 /* Deallocate memory used by aliasing data structures and the internal
5403 points-to solution. */
5404 delete_points_to_sets ();
5406 gcc_assert (!need_ssa_update_p (cfun
));
5412 gate_tree_pta (void)
5414 return flag_tree_pta
;
5417 /* A dummy pass to cause points-to information to be computed via
5418 TODO_rebuild_alias. */
5420 struct gimple_opt_pass pass_build_alias
=
5425 gate_tree_pta
, /* gate */
5429 0, /* static_pass_number */
5430 TV_NONE
, /* tv_id */
5431 PROP_cfg
| PROP_ssa
, /* properties_required */
5432 0, /* properties_provided */
5433 0, /* properties_destroyed */
5434 0, /* todo_flags_start */
5435 TODO_rebuild_alias
| TODO_dump_func
/* todo_flags_finish */
5440 /* Return true if we should execute IPA PTA. */
5444 return (flag_ipa_pta
5445 /* Don't bother doing anything if the program has errors. */
5446 && !(errorcount
|| sorrycount
));
5449 /* Execute the driver for IPA PTA. */
5451 ipa_pta_execute (void)
5453 struct cgraph_node
*node
;
5454 struct scc_info
*si
;
5457 init_alias_heapvars ();
5460 for (node
= cgraph_nodes
; node
; node
= node
->next
)
5464 varid
= create_function_info_for (node
->decl
,
5465 cgraph_node_name (node
));
5466 if (node
->local
.externally_visible
)
5468 varinfo_t fi
= get_varinfo (varid
);
5469 for (; fi
; fi
= fi
->next
)
5470 make_constraint_from (fi
, anything_id
);
5473 for (node
= cgraph_nodes
; node
; node
= node
->next
)
5477 struct function
*func
= DECL_STRUCT_FUNCTION (node
->decl
);
5479 tree old_func_decl
= current_function_decl
;
5482 "Generating constraints for %s\n",
5483 cgraph_node_name (node
));
5485 current_function_decl
= node
->decl
;
5487 FOR_EACH_BB_FN (bb
, func
)
5489 gimple_stmt_iterator gsi
;
5491 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
);
5494 gimple phi
= gsi_stmt (gsi
);
5496 if (is_gimple_reg (gimple_phi_result (phi
)))
5497 find_func_aliases (phi
);
5500 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5501 find_func_aliases (gsi_stmt (gsi
));
5503 current_function_decl
= old_func_decl
;
5508 /* Make point to anything. */
5514 fprintf (dump_file
, "Points-to analysis\n\nConstraints:\n\n");
5515 dump_constraints (dump_file
);
5520 "\nCollapsing static cycles and doing variable "
5523 init_graph (VEC_length (varinfo_t
, varmap
) * 2);
5524 build_pred_graph ();
5525 si
= perform_var_substitution (graph
);
5526 rewrite_constraints (graph
, si
);
5528 build_succ_graph ();
5529 free_var_substitution_info (si
);
5530 move_complex_constraints (graph
);
5531 unite_pointer_equivalences (graph
);
5532 find_indirect_cycles (graph
);
5534 /* Implicit nodes and predecessors are no longer necessary at this
5536 remove_preds_and_fake_succs (graph
);
5539 fprintf (dump_file
, "\nSolving graph\n");
5541 solve_graph (graph
);
5544 dump_sa_points_to_info (dump_file
);
5547 delete_alias_heapvars ();
5548 delete_points_to_sets ();
5552 struct simple_ipa_opt_pass pass_ipa_pta
=
5557 gate_ipa_pta
, /* gate */
5558 ipa_pta_execute
, /* execute */
5561 0, /* static_pass_number */
5562 TV_IPA_PTA
, /* tv_id */
5563 0, /* properties_required */
5564 0, /* properties_provided */
5565 0, /* properties_destroyed */
5566 0, /* todo_flags_start */
5567 TODO_update_ssa
/* todo_flags_finish */
5572 #include "gt-tree-ssa-structalias.h"