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 is a variable tracking a restrict pointer source. */
230 unsigned int is_restrict_var
: 1;
232 /* True if this field may contain pointers. */
233 unsigned int may_have_pointers
: 1;
235 /* True if this represents a global variable. */
236 unsigned int is_global_var
: 1;
238 /* A link to the variable for the next field in this structure. */
239 struct variable_info
*next
;
241 /* Offset of this variable, in bits, from the base variable */
242 unsigned HOST_WIDE_INT offset
;
244 /* Size of the variable, in bits. */
245 unsigned HOST_WIDE_INT size
;
247 /* Full size of the base variable, in bits. */
248 unsigned HOST_WIDE_INT fullsize
;
250 /* Name of this variable */
253 /* Tree that this variable is associated with. */
256 /* Points-to set for this variable. */
259 /* Old points-to set for this variable. */
262 typedef struct variable_info
*varinfo_t
;
264 static varinfo_t
first_vi_for_offset (varinfo_t
, unsigned HOST_WIDE_INT
);
265 static varinfo_t
first_or_preceding_vi_for_offset (varinfo_t
,
266 unsigned HOST_WIDE_INT
);
267 static varinfo_t
lookup_vi_for_tree (tree
);
269 /* Pool of variable info structures. */
270 static alloc_pool variable_info_pool
;
272 DEF_VEC_P(varinfo_t
);
274 DEF_VEC_ALLOC_P(varinfo_t
, heap
);
276 /* Table of variable info structures for constraint variables.
277 Indexed directly by variable info id. */
278 static VEC(varinfo_t
,heap
) *varmap
;
280 /* Return the varmap element N */
282 static inline varinfo_t
283 get_varinfo (unsigned int n
)
285 return VEC_index (varinfo_t
, varmap
, n
);
288 /* Static IDs for the special variables. */
289 enum { nothing_id
= 0, anything_id
= 1, readonly_id
= 2,
290 escaped_id
= 3, nonlocal_id
= 4, callused_id
= 5,
291 storedanything_id
= 6, integer_id
= 7 };
293 struct GTY(()) heapvar_map
{
295 unsigned HOST_WIDE_INT offset
;
299 heapvar_map_eq (const void *p1
, const void *p2
)
301 const struct heapvar_map
*h1
= (const struct heapvar_map
*)p1
;
302 const struct heapvar_map
*h2
= (const struct heapvar_map
*)p2
;
303 return (h1
->map
.base
.from
== h2
->map
.base
.from
304 && h1
->offset
== h2
->offset
);
308 heapvar_map_hash (struct heapvar_map
*h
)
310 return iterative_hash_host_wide_int (h
->offset
,
311 htab_hash_pointer (h
->map
.base
.from
));
314 /* Lookup a heap var for FROM, and return it if we find one. */
317 heapvar_lookup (tree from
, unsigned HOST_WIDE_INT offset
)
319 struct heapvar_map
*h
, in
;
320 in
.map
.base
.from
= from
;
322 h
= (struct heapvar_map
*) htab_find_with_hash (heapvar_for_stmt
, &in
,
323 heapvar_map_hash (&in
));
329 /* Insert a mapping FROM->TO in the heap var for statement
333 heapvar_insert (tree from
, unsigned HOST_WIDE_INT offset
, tree to
)
335 struct heapvar_map
*h
;
338 h
= GGC_NEW (struct heapvar_map
);
339 h
->map
.base
.from
= from
;
341 h
->map
.hash
= heapvar_map_hash (h
);
343 loc
= htab_find_slot_with_hash (heapvar_for_stmt
, h
, h
->map
.hash
, INSERT
);
344 gcc_assert (*loc
== NULL
);
345 *(struct heapvar_map
**) loc
= h
;
348 /* Return a new variable info structure consisting for a variable
349 named NAME, and using constraint graph node NODE. Append it
350 to the vector of variable info structures. */
353 new_var_info (tree t
, const char *name
)
355 unsigned index
= VEC_length (varinfo_t
, varmap
);
356 varinfo_t ret
= (varinfo_t
) pool_alloc (variable_info_pool
);
361 /* Vars without decl are artificial and do not have sub-variables. */
362 ret
->is_artificial_var
= (t
== NULL_TREE
);
363 ret
->is_special_var
= false;
364 ret
->is_unknown_size_var
= false;
365 ret
->is_full_var
= (t
== NULL_TREE
);
366 ret
->is_heap_var
= false;
367 ret
->is_restrict_var
= false;
368 ret
->may_have_pointers
= true;
369 ret
->is_global_var
= (t
== NULL_TREE
);
371 ret
->is_global_var
= is_global_var (t
);
372 ret
->solution
= BITMAP_ALLOC (&pta_obstack
);
373 ret
->oldsolution
= BITMAP_ALLOC (&oldpta_obstack
);
376 VEC_safe_push (varinfo_t
, heap
, varmap
, ret
);
381 typedef enum {SCALAR
, DEREF
, ADDRESSOF
} constraint_expr_type
;
383 /* An expression that appears in a constraint. */
385 struct constraint_expr
387 /* Constraint type. */
388 constraint_expr_type type
;
390 /* Variable we are referring to in the constraint. */
393 /* Offset, in bits, of this constraint from the beginning of
394 variables it ends up referring to.
396 IOW, in a deref constraint, we would deref, get the result set,
397 then add OFFSET to each member. */
398 HOST_WIDE_INT offset
;
401 /* Use 0x8000... as special unknown offset. */
402 #define UNKNOWN_OFFSET ((HOST_WIDE_INT)-1 << (HOST_BITS_PER_WIDE_INT-1))
404 typedef struct constraint_expr ce_s
;
406 DEF_VEC_ALLOC_O(ce_s
, heap
);
407 static void get_constraint_for_1 (tree
, VEC(ce_s
, heap
) **, bool);
408 static void get_constraint_for (tree
, VEC(ce_s
, heap
) **);
409 static void do_deref (VEC (ce_s
, heap
) **);
411 /* Our set constraints are made up of two constraint expressions, one
414 As described in the introduction, our set constraints each represent an
415 operation between set valued variables.
419 struct constraint_expr lhs
;
420 struct constraint_expr rhs
;
423 /* List of constraints that we use to build the constraint graph from. */
425 static VEC(constraint_t
,heap
) *constraints
;
426 static alloc_pool constraint_pool
;
430 DEF_VEC_ALLOC_I(int, heap
);
432 /* The constraint graph is represented as an array of bitmaps
433 containing successor nodes. */
435 struct constraint_graph
437 /* Size of this graph, which may be different than the number of
438 nodes in the variable map. */
441 /* Explicit successors of each node. */
444 /* Implicit predecessors of each node (Used for variable
446 bitmap
*implicit_preds
;
448 /* Explicit predecessors of each node (Used for variable substitution). */
451 /* Indirect cycle representatives, or -1 if the node has no indirect
453 int *indirect_cycles
;
455 /* Representative node for a node. rep[a] == a unless the node has
459 /* Equivalence class representative for a label. This is used for
460 variable substitution. */
463 /* Pointer equivalence label for a node. All nodes with the same
464 pointer equivalence label can be unified together at some point
465 (either during constraint optimization or after the constraint
469 /* Pointer equivalence representative for a label. This is used to
470 handle nodes that are pointer equivalent but not location
471 equivalent. We can unite these once the addressof constraints
472 are transformed into initial points-to sets. */
475 /* Pointer equivalence label for each node, used during variable
477 unsigned int *pointer_label
;
479 /* Location equivalence label for each node, used during location
480 equivalence finding. */
481 unsigned int *loc_label
;
483 /* Pointed-by set for each node, used during location equivalence
484 finding. This is pointed-by rather than pointed-to, because it
485 is constructed using the predecessor graph. */
488 /* Points to sets for pointer equivalence. This is *not* the actual
489 points-to sets for nodes. */
492 /* Bitmap of nodes where the bit is set if the node is a direct
493 node. Used for variable substitution. */
494 sbitmap direct_nodes
;
496 /* Bitmap of nodes where the bit is set if the node is address
497 taken. Used for variable substitution. */
498 bitmap address_taken
;
500 /* Vector of complex constraints for each graph node. Complex
501 constraints are those involving dereferences or offsets that are
503 VEC(constraint_t
,heap
) **complex;
506 static constraint_graph_t graph
;
508 /* During variable substitution and the offline version of indirect
509 cycle finding, we create nodes to represent dereferences and
510 address taken constraints. These represent where these start and
512 #define FIRST_REF_NODE (VEC_length (varinfo_t, varmap))
513 #define LAST_REF_NODE (FIRST_REF_NODE + (FIRST_REF_NODE - 1))
515 /* Return the representative node for NODE, if NODE has been unioned
517 This function performs path compression along the way to finding
518 the representative. */
521 find (unsigned int node
)
523 gcc_assert (node
< graph
->size
);
524 if (graph
->rep
[node
] != node
)
525 return graph
->rep
[node
] = find (graph
->rep
[node
]);
529 /* Union the TO and FROM nodes to the TO nodes.
530 Note that at some point in the future, we may want to do
531 union-by-rank, in which case we are going to have to return the
532 node we unified to. */
535 unite (unsigned int to
, unsigned int from
)
537 gcc_assert (to
< graph
->size
&& from
< graph
->size
);
538 if (to
!= from
&& graph
->rep
[from
] != to
)
540 graph
->rep
[from
] = to
;
546 /* Create a new constraint consisting of LHS and RHS expressions. */
549 new_constraint (const struct constraint_expr lhs
,
550 const struct constraint_expr rhs
)
552 constraint_t ret
= (constraint_t
) pool_alloc (constraint_pool
);
558 /* Print out constraint C to FILE. */
561 dump_constraint (FILE *file
, constraint_t c
)
563 if (c
->lhs
.type
== ADDRESSOF
)
565 else if (c
->lhs
.type
== DEREF
)
567 fprintf (file
, "%s", get_varinfo (c
->lhs
.var
)->name
);
568 if (c
->lhs
.offset
== UNKNOWN_OFFSET
)
569 fprintf (file
, " + UNKNOWN");
570 else if (c
->lhs
.offset
!= 0)
571 fprintf (file
, " + " HOST_WIDE_INT_PRINT_DEC
, c
->lhs
.offset
);
572 fprintf (file
, " = ");
573 if (c
->rhs
.type
== ADDRESSOF
)
575 else if (c
->rhs
.type
== DEREF
)
577 fprintf (file
, "%s", get_varinfo (c
->rhs
.var
)->name
);
578 if (c
->rhs
.offset
== UNKNOWN_OFFSET
)
579 fprintf (file
, " + UNKNOWN");
580 else if (c
->rhs
.offset
!= 0)
581 fprintf (file
, " + " HOST_WIDE_INT_PRINT_DEC
, c
->rhs
.offset
);
582 fprintf (file
, "\n");
586 void debug_constraint (constraint_t
);
587 void debug_constraints (void);
588 void debug_constraint_graph (void);
589 void debug_solution_for_var (unsigned int);
590 void debug_sa_points_to_info (void);
592 /* Print out constraint C to stderr. */
595 debug_constraint (constraint_t c
)
597 dump_constraint (stderr
, c
);
600 /* Print out all constraints to FILE */
603 dump_constraints (FILE *file
)
607 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
608 dump_constraint (file
, c
);
611 /* Print out all constraints to stderr. */
614 debug_constraints (void)
616 dump_constraints (stderr
);
619 /* Print out to FILE the edge in the constraint graph that is created by
620 constraint c. The edge may have a label, depending on the type of
621 constraint that it represents. If complex1, e.g: a = *b, then the label
622 is "=*", if complex2, e.g: *a = b, then the label is "*=", if
623 complex with an offset, e.g: a = b + 8, then the label is "+".
624 Otherwise the edge has no label. */
627 dump_constraint_edge (FILE *file
, constraint_t c
)
629 if (c
->rhs
.type
!= ADDRESSOF
)
631 const char *src
= get_varinfo (c
->rhs
.var
)->name
;
632 const char *dst
= get_varinfo (c
->lhs
.var
)->name
;
633 fprintf (file
, " \"%s\" -> \"%s\" ", src
, dst
);
634 /* Due to preprocessing of constraints, instructions like *a = *b are
635 illegal; thus, we do not have to handle such cases. */
636 if (c
->lhs
.type
== DEREF
)
637 fprintf (file
, " [ label=\"*=\" ] ;\n");
638 else if (c
->rhs
.type
== DEREF
)
639 fprintf (file
, " [ label=\"=*\" ] ;\n");
642 /* We must check the case where the constraint is an offset.
643 In this case, it is treated as a complex constraint. */
644 if (c
->rhs
.offset
!= c
->lhs
.offset
)
645 fprintf (file
, " [ label=\"+\" ] ;\n");
647 fprintf (file
, " ;\n");
652 /* Print the constraint graph in dot format. */
655 dump_constraint_graph (FILE *file
)
657 unsigned int i
=0, size
;
660 /* Only print the graph if it has already been initialized: */
664 /* Print the constraints used to produce the constraint graph. The
665 constraints will be printed as comments in the dot file: */
666 fprintf (file
, "\n\n/* Constraints used in the constraint graph:\n");
667 dump_constraints (file
);
668 fprintf (file
, "*/\n");
670 /* Prints the header of the dot file: */
671 fprintf (file
, "\n\n// The constraint graph in dot format:\n");
672 fprintf (file
, "strict digraph {\n");
673 fprintf (file
, " node [\n shape = box\n ]\n");
674 fprintf (file
, " edge [\n fontsize = \"12\"\n ]\n");
675 fprintf (file
, "\n // List of nodes in the constraint graph:\n");
677 /* The next lines print the nodes in the graph. In order to get the
678 number of nodes in the graph, we must choose the minimum between the
679 vector VEC (varinfo_t, varmap) and graph->size. If the graph has not
680 yet been initialized, then graph->size == 0, otherwise we must only
681 read nodes that have an entry in VEC (varinfo_t, varmap). */
682 size
= VEC_length (varinfo_t
, varmap
);
683 size
= size
< graph
->size
? size
: graph
->size
;
684 for (i
= 0; i
< size
; i
++)
686 const char *name
= get_varinfo (graph
->rep
[i
])->name
;
687 fprintf (file
, " \"%s\" ;\n", name
);
690 /* Go over the list of constraints printing the edges in the constraint
692 fprintf (file
, "\n // The constraint edges:\n");
693 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
695 dump_constraint_edge (file
, c
);
697 /* Prints the tail of the dot file. By now, only the closing bracket. */
698 fprintf (file
, "}\n\n\n");
701 /* Print out the constraint graph to stderr. */
704 debug_constraint_graph (void)
706 dump_constraint_graph (stderr
);
711 The solver is a simple worklist solver, that works on the following
714 sbitmap changed_nodes = all zeroes;
716 For each node that is not already collapsed:
718 set bit in changed nodes
720 while (changed_count > 0)
722 compute topological ordering for constraint graph
724 find and collapse cycles in the constraint graph (updating
725 changed if necessary)
727 for each node (n) in the graph in topological order:
730 Process each complex constraint associated with the node,
731 updating changed if necessary.
733 For each outgoing edge from n, propagate the solution from n to
734 the destination of the edge, updating changed as necessary.
738 /* Return true if two constraint expressions A and B are equal. */
741 constraint_expr_equal (struct constraint_expr a
, struct constraint_expr b
)
743 return a
.type
== b
.type
&& a
.var
== b
.var
&& a
.offset
== b
.offset
;
746 /* Return true if constraint expression A is less than constraint expression
747 B. This is just arbitrary, but consistent, in order to give them an
751 constraint_expr_less (struct constraint_expr a
, struct constraint_expr b
)
753 if (a
.type
== b
.type
)
756 return a
.offset
< b
.offset
;
758 return a
.var
< b
.var
;
761 return a
.type
< b
.type
;
764 /* Return true if constraint A is less than constraint B. This is just
765 arbitrary, but consistent, in order to give them an ordering. */
768 constraint_less (const constraint_t a
, const constraint_t b
)
770 if (constraint_expr_less (a
->lhs
, b
->lhs
))
772 else if (constraint_expr_less (b
->lhs
, a
->lhs
))
775 return constraint_expr_less (a
->rhs
, b
->rhs
);
778 /* Return true if two constraints A and B are equal. */
781 constraint_equal (struct constraint a
, struct constraint b
)
783 return constraint_expr_equal (a
.lhs
, b
.lhs
)
784 && constraint_expr_equal (a
.rhs
, b
.rhs
);
788 /* Find a constraint LOOKFOR in the sorted constraint vector VEC */
791 constraint_vec_find (VEC(constraint_t
,heap
) *vec
,
792 struct constraint lookfor
)
800 place
= VEC_lower_bound (constraint_t
, vec
, &lookfor
, constraint_less
);
801 if (place
>= VEC_length (constraint_t
, vec
))
803 found
= VEC_index (constraint_t
, vec
, place
);
804 if (!constraint_equal (*found
, lookfor
))
809 /* Union two constraint vectors, TO and FROM. Put the result in TO. */
812 constraint_set_union (VEC(constraint_t
,heap
) **to
,
813 VEC(constraint_t
,heap
) **from
)
818 for (i
= 0; VEC_iterate (constraint_t
, *from
, i
, c
); i
++)
820 if (constraint_vec_find (*to
, *c
) == NULL
)
822 unsigned int place
= VEC_lower_bound (constraint_t
, *to
, c
,
824 VEC_safe_insert (constraint_t
, heap
, *to
, place
, c
);
829 /* Expands the solution in SET to all sub-fields of variables included.
830 Union the expanded result into RESULT. */
833 solution_set_expand (bitmap result
, bitmap set
)
839 /* In a first pass record all variables we need to add all
840 sub-fields off. This avoids quadratic behavior. */
841 EXECUTE_IF_SET_IN_BITMAP (set
, 0, j
, bi
)
843 varinfo_t v
= get_varinfo (j
);
844 if (v
->is_artificial_var
847 v
= lookup_vi_for_tree (v
->decl
);
849 vars
= BITMAP_ALLOC (NULL
);
850 bitmap_set_bit (vars
, v
->id
);
853 /* In the second pass now do the addition to the solution and
854 to speed up solving add it to the delta as well. */
857 EXECUTE_IF_SET_IN_BITMAP (vars
, 0, j
, bi
)
859 varinfo_t v
= get_varinfo (j
);
860 for (; v
!= NULL
; v
= v
->next
)
861 bitmap_set_bit (result
, v
->id
);
867 /* Take a solution set SET, add OFFSET to each member of the set, and
868 overwrite SET with the result when done. */
871 solution_set_add (bitmap set
, HOST_WIDE_INT offset
)
873 bitmap result
= BITMAP_ALLOC (&iteration_obstack
);
877 /* If the offset is unknown we have to expand the solution to
879 if (offset
== UNKNOWN_OFFSET
)
881 solution_set_expand (set
, set
);
885 EXECUTE_IF_SET_IN_BITMAP (set
, 0, i
, bi
)
887 varinfo_t vi
= get_varinfo (i
);
889 /* If this is a variable with just one field just set its bit
891 if (vi
->is_artificial_var
892 || vi
->is_unknown_size_var
894 bitmap_set_bit (result
, i
);
897 unsigned HOST_WIDE_INT fieldoffset
= vi
->offset
+ offset
;
899 /* If the offset makes the pointer point to before the
900 variable use offset zero for the field lookup. */
902 && fieldoffset
> vi
->offset
)
906 vi
= first_or_preceding_vi_for_offset (vi
, fieldoffset
);
908 bitmap_set_bit (result
, vi
->id
);
909 /* If the result is not exactly at fieldoffset include the next
910 field as well. See get_constraint_for_ptr_offset for more
912 if (vi
->offset
!= fieldoffset
914 bitmap_set_bit (result
, vi
->next
->id
);
918 bitmap_copy (set
, result
);
919 BITMAP_FREE (result
);
922 /* Union solution sets TO and FROM, and add INC to each member of FROM in the
926 set_union_with_increment (bitmap to
, bitmap from
, HOST_WIDE_INT inc
)
929 return bitmap_ior_into (to
, from
);
935 tmp
= BITMAP_ALLOC (&iteration_obstack
);
936 bitmap_copy (tmp
, from
);
937 solution_set_add (tmp
, inc
);
938 res
= bitmap_ior_into (to
, tmp
);
944 /* Insert constraint C into the list of complex constraints for graph
948 insert_into_complex (constraint_graph_t graph
,
949 unsigned int var
, constraint_t c
)
951 VEC (constraint_t
, heap
) *complex = graph
->complex[var
];
952 unsigned int place
= VEC_lower_bound (constraint_t
, complex, c
,
955 /* Only insert constraints that do not already exist. */
956 if (place
>= VEC_length (constraint_t
, complex)
957 || !constraint_equal (*c
, *VEC_index (constraint_t
, complex, place
)))
958 VEC_safe_insert (constraint_t
, heap
, graph
->complex[var
], place
, c
);
962 /* Condense two variable nodes into a single variable node, by moving
963 all associated info from SRC to TO. */
966 merge_node_constraints (constraint_graph_t graph
, unsigned int to
,
972 gcc_assert (find (from
) == to
);
974 /* Move all complex constraints from src node into to node */
975 for (i
= 0; VEC_iterate (constraint_t
, graph
->complex[from
], i
, c
); i
++)
977 /* In complex constraints for node src, we may have either
978 a = *src, and *src = a, or an offseted constraint which are
979 always added to the rhs node's constraints. */
981 if (c
->rhs
.type
== DEREF
)
983 else if (c
->lhs
.type
== DEREF
)
988 constraint_set_union (&graph
->complex[to
], &graph
->complex[from
]);
989 VEC_free (constraint_t
, heap
, graph
->complex[from
]);
990 graph
->complex[from
] = NULL
;
994 /* Remove edges involving NODE from GRAPH. */
997 clear_edges_for_node (constraint_graph_t graph
, unsigned int node
)
999 if (graph
->succs
[node
])
1000 BITMAP_FREE (graph
->succs
[node
]);
1003 /* Merge GRAPH nodes FROM and TO into node TO. */
1006 merge_graph_nodes (constraint_graph_t graph
, unsigned int to
,
1009 if (graph
->indirect_cycles
[from
] != -1)
1011 /* If we have indirect cycles with the from node, and we have
1012 none on the to node, the to node has indirect cycles from the
1013 from node now that they are unified.
1014 If indirect cycles exist on both, unify the nodes that they
1015 are in a cycle with, since we know they are in a cycle with
1017 if (graph
->indirect_cycles
[to
] == -1)
1018 graph
->indirect_cycles
[to
] = graph
->indirect_cycles
[from
];
1021 /* Merge all the successor edges. */
1022 if (graph
->succs
[from
])
1024 if (!graph
->succs
[to
])
1025 graph
->succs
[to
] = BITMAP_ALLOC (&pta_obstack
);
1026 bitmap_ior_into (graph
->succs
[to
],
1027 graph
->succs
[from
]);
1030 clear_edges_for_node (graph
, from
);
1034 /* Add an indirect graph edge to GRAPH, going from TO to FROM if
1035 it doesn't exist in the graph already. */
1038 add_implicit_graph_edge (constraint_graph_t graph
, unsigned int to
,
1044 if (!graph
->implicit_preds
[to
])
1045 graph
->implicit_preds
[to
] = BITMAP_ALLOC (&predbitmap_obstack
);
1047 if (bitmap_set_bit (graph
->implicit_preds
[to
], from
))
1048 stats
.num_implicit_edges
++;
1051 /* Add a predecessor graph edge to GRAPH, going from TO to FROM if
1052 it doesn't exist in the graph already.
1053 Return false if the edge already existed, true otherwise. */
1056 add_pred_graph_edge (constraint_graph_t graph
, unsigned int to
,
1059 if (!graph
->preds
[to
])
1060 graph
->preds
[to
] = BITMAP_ALLOC (&predbitmap_obstack
);
1061 bitmap_set_bit (graph
->preds
[to
], from
);
1064 /* Add a graph edge to GRAPH, going from FROM to TO if
1065 it doesn't exist in the graph already.
1066 Return false if the edge already existed, true otherwise. */
1069 add_graph_edge (constraint_graph_t graph
, unsigned int to
,
1080 if (!graph
->succs
[from
])
1081 graph
->succs
[from
] = BITMAP_ALLOC (&pta_obstack
);
1082 if (bitmap_set_bit (graph
->succs
[from
], to
))
1085 if (to
< FIRST_REF_NODE
&& from
< FIRST_REF_NODE
)
1093 /* Return true if {DEST.SRC} is an existing graph edge in GRAPH. */
1096 valid_graph_edge (constraint_graph_t graph
, unsigned int src
,
1099 return (graph
->succs
[dest
]
1100 && bitmap_bit_p (graph
->succs
[dest
], src
));
1103 /* Initialize the constraint graph structure to contain SIZE nodes. */
1106 init_graph (unsigned int size
)
1110 graph
= XCNEW (struct constraint_graph
);
1112 graph
->succs
= XCNEWVEC (bitmap
, graph
->size
);
1113 graph
->indirect_cycles
= XNEWVEC (int, graph
->size
);
1114 graph
->rep
= XNEWVEC (unsigned int, graph
->size
);
1115 graph
->complex = XCNEWVEC (VEC(constraint_t
, heap
) *, size
);
1116 graph
->pe
= XCNEWVEC (unsigned int, graph
->size
);
1117 graph
->pe_rep
= XNEWVEC (int, graph
->size
);
1119 for (j
= 0; j
< graph
->size
; j
++)
1122 graph
->pe_rep
[j
] = -1;
1123 graph
->indirect_cycles
[j
] = -1;
1127 /* Build the constraint graph, adding only predecessor edges right now. */
1130 build_pred_graph (void)
1136 graph
->implicit_preds
= XCNEWVEC (bitmap
, graph
->size
);
1137 graph
->preds
= XCNEWVEC (bitmap
, graph
->size
);
1138 graph
->pointer_label
= XCNEWVEC (unsigned int, graph
->size
);
1139 graph
->loc_label
= XCNEWVEC (unsigned int, graph
->size
);
1140 graph
->pointed_by
= XCNEWVEC (bitmap
, graph
->size
);
1141 graph
->points_to
= XCNEWVEC (bitmap
, graph
->size
);
1142 graph
->eq_rep
= XNEWVEC (int, graph
->size
);
1143 graph
->direct_nodes
= sbitmap_alloc (graph
->size
);
1144 graph
->address_taken
= BITMAP_ALLOC (&predbitmap_obstack
);
1145 sbitmap_zero (graph
->direct_nodes
);
1147 for (j
= 0; j
< FIRST_REF_NODE
; j
++)
1149 if (!get_varinfo (j
)->is_special_var
)
1150 SET_BIT (graph
->direct_nodes
, j
);
1153 for (j
= 0; j
< graph
->size
; j
++)
1154 graph
->eq_rep
[j
] = -1;
1156 for (j
= 0; j
< VEC_length (varinfo_t
, varmap
); j
++)
1157 graph
->indirect_cycles
[j
] = -1;
1159 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
1161 struct constraint_expr lhs
= c
->lhs
;
1162 struct constraint_expr rhs
= c
->rhs
;
1163 unsigned int lhsvar
= lhs
.var
;
1164 unsigned int rhsvar
= rhs
.var
;
1166 if (lhs
.type
== DEREF
)
1169 if (rhs
.offset
== 0 && lhs
.offset
== 0 && rhs
.type
== SCALAR
)
1170 add_pred_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1172 else if (rhs
.type
== DEREF
)
1175 if (rhs
.offset
== 0 && lhs
.offset
== 0 && lhs
.type
== SCALAR
)
1176 add_pred_graph_edge (graph
, lhsvar
, FIRST_REF_NODE
+ rhsvar
);
1178 RESET_BIT (graph
->direct_nodes
, lhsvar
);
1180 else if (rhs
.type
== ADDRESSOF
)
1185 if (graph
->points_to
[lhsvar
] == NULL
)
1186 graph
->points_to
[lhsvar
] = BITMAP_ALLOC (&predbitmap_obstack
);
1187 bitmap_set_bit (graph
->points_to
[lhsvar
], rhsvar
);
1189 if (graph
->pointed_by
[rhsvar
] == NULL
)
1190 graph
->pointed_by
[rhsvar
] = BITMAP_ALLOC (&predbitmap_obstack
);
1191 bitmap_set_bit (graph
->pointed_by
[rhsvar
], lhsvar
);
1193 /* Implicitly, *x = y */
1194 add_implicit_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1196 /* All related variables are no longer direct nodes. */
1197 RESET_BIT (graph
->direct_nodes
, rhsvar
);
1198 v
= get_varinfo (rhsvar
);
1199 if (!v
->is_full_var
)
1201 v
= lookup_vi_for_tree (v
->decl
);
1204 RESET_BIT (graph
->direct_nodes
, v
->id
);
1209 bitmap_set_bit (graph
->address_taken
, rhsvar
);
1211 else if (lhsvar
> anything_id
1212 && lhsvar
!= rhsvar
&& lhs
.offset
== 0 && rhs
.offset
== 0)
1215 add_pred_graph_edge (graph
, lhsvar
, rhsvar
);
1216 /* Implicitly, *x = *y */
1217 add_implicit_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
,
1218 FIRST_REF_NODE
+ rhsvar
);
1220 else if (lhs
.offset
!= 0 || rhs
.offset
!= 0)
1222 if (rhs
.offset
!= 0)
1223 RESET_BIT (graph
->direct_nodes
, lhs
.var
);
1224 else if (lhs
.offset
!= 0)
1225 RESET_BIT (graph
->direct_nodes
, rhs
.var
);
1230 /* Build the constraint graph, adding successor edges. */
1233 build_succ_graph (void)
1238 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
1240 struct constraint_expr lhs
;
1241 struct constraint_expr rhs
;
1242 unsigned int lhsvar
;
1243 unsigned int rhsvar
;
1250 lhsvar
= find (lhs
.var
);
1251 rhsvar
= find (rhs
.var
);
1253 if (lhs
.type
== DEREF
)
1255 if (rhs
.offset
== 0 && lhs
.offset
== 0 && rhs
.type
== SCALAR
)
1256 add_graph_edge (graph
, FIRST_REF_NODE
+ lhsvar
, rhsvar
);
1258 else if (rhs
.type
== DEREF
)
1260 if (rhs
.offset
== 0 && lhs
.offset
== 0 && lhs
.type
== SCALAR
)
1261 add_graph_edge (graph
, lhsvar
, FIRST_REF_NODE
+ rhsvar
);
1263 else if (rhs
.type
== ADDRESSOF
)
1266 gcc_assert (find (rhs
.var
) == rhs
.var
);
1267 bitmap_set_bit (get_varinfo (lhsvar
)->solution
, rhsvar
);
1269 else if (lhsvar
> anything_id
1270 && lhsvar
!= rhsvar
&& lhs
.offset
== 0 && rhs
.offset
== 0)
1272 add_graph_edge (graph
, lhsvar
, rhsvar
);
1276 /* Add edges from STOREDANYTHING to all non-direct nodes. */
1277 t
= find (storedanything_id
);
1278 for (i
= integer_id
+ 1; i
< FIRST_REF_NODE
; ++i
)
1280 if (!TEST_BIT (graph
->direct_nodes
, i
))
1281 add_graph_edge (graph
, find (i
), t
);
1286 /* Changed variables on the last iteration. */
1287 static unsigned int changed_count
;
1288 static sbitmap changed
;
1290 DEF_VEC_I(unsigned);
1291 DEF_VEC_ALLOC_I(unsigned,heap
);
1294 /* Strongly Connected Component visitation info. */
1301 unsigned int *node_mapping
;
1303 VEC(unsigned,heap
) *scc_stack
;
1307 /* Recursive routine to find strongly connected components in GRAPH.
1308 SI is the SCC info to store the information in, and N is the id of current
1309 graph node we are processing.
1311 This is Tarjan's strongly connected component finding algorithm, as
1312 modified by Nuutila to keep only non-root nodes on the stack.
1313 The algorithm can be found in "On finding the strongly connected
1314 connected components in a directed graph" by Esko Nuutila and Eljas
1315 Soisalon-Soininen, in Information Processing Letters volume 49,
1316 number 1, pages 9-14. */
1319 scc_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
1323 unsigned int my_dfs
;
1325 SET_BIT (si
->visited
, n
);
1326 si
->dfs
[n
] = si
->current_index
++;
1327 my_dfs
= si
->dfs
[n
];
1329 /* Visit all the successors. */
1330 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->succs
[n
], 0, i
, bi
)
1334 if (i
> LAST_REF_NODE
)
1338 if (TEST_BIT (si
->deleted
, w
))
1341 if (!TEST_BIT (si
->visited
, w
))
1342 scc_visit (graph
, si
, w
);
1344 unsigned int t
= find (w
);
1345 unsigned int nnode
= find (n
);
1346 gcc_assert (nnode
== n
);
1348 if (si
->dfs
[t
] < si
->dfs
[nnode
])
1349 si
->dfs
[n
] = si
->dfs
[t
];
1353 /* See if any components have been identified. */
1354 if (si
->dfs
[n
] == my_dfs
)
1356 if (VEC_length (unsigned, si
->scc_stack
) > 0
1357 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
1359 bitmap scc
= BITMAP_ALLOC (NULL
);
1360 bool have_ref_node
= n
>= FIRST_REF_NODE
;
1361 unsigned int lowest_node
;
1364 bitmap_set_bit (scc
, n
);
1366 while (VEC_length (unsigned, si
->scc_stack
) != 0
1367 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
1369 unsigned int w
= VEC_pop (unsigned, si
->scc_stack
);
1371 bitmap_set_bit (scc
, w
);
1372 if (w
>= FIRST_REF_NODE
)
1373 have_ref_node
= true;
1376 lowest_node
= bitmap_first_set_bit (scc
);
1377 gcc_assert (lowest_node
< FIRST_REF_NODE
);
1379 /* Collapse the SCC nodes into a single node, and mark the
1381 EXECUTE_IF_SET_IN_BITMAP (scc
, 0, i
, bi
)
1383 if (i
< FIRST_REF_NODE
)
1385 if (unite (lowest_node
, i
))
1386 unify_nodes (graph
, lowest_node
, i
, false);
1390 unite (lowest_node
, i
);
1391 graph
->indirect_cycles
[i
- FIRST_REF_NODE
] = lowest_node
;
1395 SET_BIT (si
->deleted
, n
);
1398 VEC_safe_push (unsigned, heap
, si
->scc_stack
, n
);
1401 /* Unify node FROM into node TO, updating the changed count if
1402 necessary when UPDATE_CHANGED is true. */
1405 unify_nodes (constraint_graph_t graph
, unsigned int to
, unsigned int from
,
1406 bool update_changed
)
1409 gcc_assert (to
!= from
&& find (to
) == to
);
1410 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
1411 fprintf (dump_file
, "Unifying %s to %s\n",
1412 get_varinfo (from
)->name
,
1413 get_varinfo (to
)->name
);
1416 stats
.unified_vars_dynamic
++;
1418 stats
.unified_vars_static
++;
1420 merge_graph_nodes (graph
, to
, from
);
1421 merge_node_constraints (graph
, to
, from
);
1423 /* Mark TO as changed if FROM was changed. If TO was already marked
1424 as changed, decrease the changed count. */
1426 if (update_changed
&& TEST_BIT (changed
, from
))
1428 RESET_BIT (changed
, from
);
1429 if (!TEST_BIT (changed
, to
))
1430 SET_BIT (changed
, to
);
1433 gcc_assert (changed_count
> 0);
1437 if (get_varinfo (from
)->solution
)
1439 /* If the solution changes because of the merging, we need to mark
1440 the variable as changed. */
1441 if (bitmap_ior_into (get_varinfo (to
)->solution
,
1442 get_varinfo (from
)->solution
))
1444 if (update_changed
&& !TEST_BIT (changed
, to
))
1446 SET_BIT (changed
, to
);
1451 BITMAP_FREE (get_varinfo (from
)->solution
);
1452 BITMAP_FREE (get_varinfo (from
)->oldsolution
);
1454 if (stats
.iterations
> 0)
1456 BITMAP_FREE (get_varinfo (to
)->oldsolution
);
1457 get_varinfo (to
)->oldsolution
= BITMAP_ALLOC (&oldpta_obstack
);
1460 if (valid_graph_edge (graph
, to
, to
))
1462 if (graph
->succs
[to
])
1463 bitmap_clear_bit (graph
->succs
[to
], to
);
1467 /* Information needed to compute the topological ordering of a graph. */
1471 /* sbitmap of visited nodes. */
1473 /* Array that stores the topological order of the graph, *in
1475 VEC(unsigned,heap
) *topo_order
;
1479 /* Initialize and return a topological info structure. */
1481 static struct topo_info
*
1482 init_topo_info (void)
1484 size_t size
= graph
->size
;
1485 struct topo_info
*ti
= XNEW (struct topo_info
);
1486 ti
->visited
= sbitmap_alloc (size
);
1487 sbitmap_zero (ti
->visited
);
1488 ti
->topo_order
= VEC_alloc (unsigned, heap
, 1);
1493 /* Free the topological sort info pointed to by TI. */
1496 free_topo_info (struct topo_info
*ti
)
1498 sbitmap_free (ti
->visited
);
1499 VEC_free (unsigned, heap
, ti
->topo_order
);
1503 /* Visit the graph in topological order, and store the order in the
1504 topo_info structure. */
1507 topo_visit (constraint_graph_t graph
, struct topo_info
*ti
,
1513 SET_BIT (ti
->visited
, n
);
1515 if (graph
->succs
[n
])
1516 EXECUTE_IF_SET_IN_BITMAP (graph
->succs
[n
], 0, j
, bi
)
1518 if (!TEST_BIT (ti
->visited
, j
))
1519 topo_visit (graph
, ti
, j
);
1522 VEC_safe_push (unsigned, heap
, ti
->topo_order
, n
);
1525 /* Process a constraint C that represents x = *(y + off), using DELTA as the
1526 starting solution for y. */
1529 do_sd_constraint (constraint_graph_t graph
, constraint_t c
,
1532 unsigned int lhs
= c
->lhs
.var
;
1534 bitmap sol
= get_varinfo (lhs
)->solution
;
1537 HOST_WIDE_INT roffset
= c
->rhs
.offset
;
1539 /* Our IL does not allow this. */
1540 gcc_assert (c
->lhs
.offset
== 0);
1542 /* If the solution of Y contains anything it is good enough to transfer
1544 if (bitmap_bit_p (delta
, anything_id
))
1546 flag
|= bitmap_set_bit (sol
, anything_id
);
1550 /* If we do not know at with offset the rhs is dereferenced compute
1551 the reachability set of DELTA, conservatively assuming it is
1552 dereferenced at all valid offsets. */
1553 if (roffset
== UNKNOWN_OFFSET
)
1555 solution_set_expand (delta
, delta
);
1556 /* No further offset processing is necessary. */
1560 /* For each variable j in delta (Sol(y)), add
1561 an edge in the graph from j to x, and union Sol(j) into Sol(x). */
1562 EXECUTE_IF_SET_IN_BITMAP (delta
, 0, j
, bi
)
1564 varinfo_t v
= get_varinfo (j
);
1565 HOST_WIDE_INT fieldoffset
= v
->offset
+ roffset
;
1569 fieldoffset
= v
->offset
;
1570 else if (roffset
!= 0)
1571 v
= first_vi_for_offset (v
, fieldoffset
);
1572 /* If the access is outside of the variable we can ignore it. */
1580 /* Adding edges from the special vars is pointless.
1581 They don't have sets that can change. */
1582 if (get_varinfo (t
)->is_special_var
)
1583 flag
|= bitmap_ior_into (sol
, get_varinfo (t
)->solution
);
1584 /* Merging the solution from ESCAPED needlessly increases
1585 the set. Use ESCAPED as representative instead. */
1586 else if (v
->id
== escaped_id
)
1587 flag
|= bitmap_set_bit (sol
, escaped_id
);
1588 else if (add_graph_edge (graph
, lhs
, t
))
1589 flag
|= bitmap_ior_into (sol
, get_varinfo (t
)->solution
);
1591 /* If the variable is not exactly at the requested offset
1592 we have to include the next one. */
1593 if (v
->offset
== (unsigned HOST_WIDE_INT
)fieldoffset
1598 fieldoffset
= v
->offset
;
1604 /* If the LHS solution changed, mark the var as changed. */
1607 get_varinfo (lhs
)->solution
= sol
;
1608 if (!TEST_BIT (changed
, lhs
))
1610 SET_BIT (changed
, lhs
);
1616 /* Process a constraint C that represents *(x + off) = y using DELTA
1617 as the starting solution for x. */
1620 do_ds_constraint (constraint_t c
, bitmap delta
)
1622 unsigned int rhs
= c
->rhs
.var
;
1623 bitmap sol
= get_varinfo (rhs
)->solution
;
1626 HOST_WIDE_INT loff
= c
->lhs
.offset
;
1628 /* Our IL does not allow this. */
1629 gcc_assert (c
->rhs
.offset
== 0);
1631 /* If the solution of y contains ANYTHING simply use the ANYTHING
1632 solution. This avoids needlessly increasing the points-to sets. */
1633 if (bitmap_bit_p (sol
, anything_id
))
1634 sol
= get_varinfo (find (anything_id
))->solution
;
1636 /* If the solution for x contains ANYTHING we have to merge the
1637 solution of y into all pointer variables which we do via
1639 if (bitmap_bit_p (delta
, anything_id
))
1641 unsigned t
= find (storedanything_id
);
1642 if (add_graph_edge (graph
, t
, rhs
))
1644 if (bitmap_ior_into (get_varinfo (t
)->solution
, sol
))
1646 if (!TEST_BIT (changed
, t
))
1648 SET_BIT (changed
, t
);
1656 /* If we do not know at with offset the rhs is dereferenced compute
1657 the reachability set of DELTA, conservatively assuming it is
1658 dereferenced at all valid offsets. */
1659 if (loff
== UNKNOWN_OFFSET
)
1661 solution_set_expand (delta
, delta
);
1665 /* For each member j of delta (Sol(x)), add an edge from y to j and
1666 union Sol(y) into Sol(j) */
1667 EXECUTE_IF_SET_IN_BITMAP (delta
, 0, j
, bi
)
1669 varinfo_t v
= get_varinfo (j
);
1671 HOST_WIDE_INT fieldoffset
= v
->offset
+ loff
;
1673 /* If v is a global variable then this is an escape point. */
1674 if (v
->is_global_var
)
1676 t
= find (escaped_id
);
1677 if (add_graph_edge (graph
, t
, rhs
)
1678 && bitmap_ior_into (get_varinfo (t
)->solution
, sol
)
1679 && !TEST_BIT (changed
, t
))
1681 SET_BIT (changed
, t
);
1686 if (v
->is_special_var
)
1690 fieldoffset
= v
->offset
;
1692 v
= first_vi_for_offset (v
, fieldoffset
);
1693 /* If the access is outside of the variable we can ignore it. */
1699 if (v
->may_have_pointers
)
1702 if (add_graph_edge (graph
, t
, rhs
)
1703 && bitmap_ior_into (get_varinfo (t
)->solution
, sol
)
1704 && !TEST_BIT (changed
, t
))
1706 SET_BIT (changed
, t
);
1711 /* If the variable is not exactly at the requested offset
1712 we have to include the next one. */
1713 if (v
->offset
== (unsigned HOST_WIDE_INT
)fieldoffset
1718 fieldoffset
= v
->offset
;
1724 /* Handle a non-simple (simple meaning requires no iteration),
1725 constraint (IE *x = &y, x = *y, *x = y, and x = y with offsets involved). */
1728 do_complex_constraint (constraint_graph_t graph
, constraint_t c
, bitmap delta
)
1730 if (c
->lhs
.type
== DEREF
)
1732 if (c
->rhs
.type
== ADDRESSOF
)
1739 do_ds_constraint (c
, delta
);
1742 else if (c
->rhs
.type
== DEREF
)
1745 if (!(get_varinfo (c
->lhs
.var
)->is_special_var
))
1746 do_sd_constraint (graph
, c
, delta
);
1754 gcc_assert (c
->rhs
.type
== SCALAR
&& c
->lhs
.type
== SCALAR
);
1755 solution
= get_varinfo (c
->rhs
.var
)->solution
;
1756 tmp
= get_varinfo (c
->lhs
.var
)->solution
;
1758 flag
= set_union_with_increment (tmp
, solution
, c
->rhs
.offset
);
1762 get_varinfo (c
->lhs
.var
)->solution
= tmp
;
1763 if (!TEST_BIT (changed
, c
->lhs
.var
))
1765 SET_BIT (changed
, c
->lhs
.var
);
1772 /* Initialize and return a new SCC info structure. */
1774 static struct scc_info
*
1775 init_scc_info (size_t size
)
1777 struct scc_info
*si
= XNEW (struct scc_info
);
1780 si
->current_index
= 0;
1781 si
->visited
= sbitmap_alloc (size
);
1782 sbitmap_zero (si
->visited
);
1783 si
->deleted
= sbitmap_alloc (size
);
1784 sbitmap_zero (si
->deleted
);
1785 si
->node_mapping
= XNEWVEC (unsigned int, size
);
1786 si
->dfs
= XCNEWVEC (unsigned int, size
);
1788 for (i
= 0; i
< size
; i
++)
1789 si
->node_mapping
[i
] = i
;
1791 si
->scc_stack
= VEC_alloc (unsigned, heap
, 1);
1795 /* Free an SCC info structure pointed to by SI */
1798 free_scc_info (struct scc_info
*si
)
1800 sbitmap_free (si
->visited
);
1801 sbitmap_free (si
->deleted
);
1802 free (si
->node_mapping
);
1804 VEC_free (unsigned, heap
, si
->scc_stack
);
1809 /* Find indirect cycles in GRAPH that occur, using strongly connected
1810 components, and note them in the indirect cycles map.
1812 This technique comes from Ben Hardekopf and Calvin Lin,
1813 "It Pays to be Lazy: Fast and Accurate Pointer Analysis for Millions of
1814 Lines of Code", submitted to PLDI 2007. */
1817 find_indirect_cycles (constraint_graph_t graph
)
1820 unsigned int size
= graph
->size
;
1821 struct scc_info
*si
= init_scc_info (size
);
1823 for (i
= 0; i
< MIN (LAST_REF_NODE
, size
); i
++ )
1824 if (!TEST_BIT (si
->visited
, i
) && find (i
) == i
)
1825 scc_visit (graph
, si
, i
);
1830 /* Compute a topological ordering for GRAPH, and store the result in the
1831 topo_info structure TI. */
1834 compute_topo_order (constraint_graph_t graph
,
1835 struct topo_info
*ti
)
1838 unsigned int size
= graph
->size
;
1840 for (i
= 0; i
!= size
; ++i
)
1841 if (!TEST_BIT (ti
->visited
, i
) && find (i
) == i
)
1842 topo_visit (graph
, ti
, i
);
1845 /* Structure used to for hash value numbering of pointer equivalence
1848 typedef struct equiv_class_label
1851 unsigned int equivalence_class
;
1853 } *equiv_class_label_t
;
1854 typedef const struct equiv_class_label
*const_equiv_class_label_t
;
1856 /* A hashtable for mapping a bitmap of labels->pointer equivalence
1858 static htab_t pointer_equiv_class_table
;
1860 /* A hashtable for mapping a bitmap of labels->location equivalence
1862 static htab_t location_equiv_class_table
;
1864 /* Hash function for a equiv_class_label_t */
1867 equiv_class_label_hash (const void *p
)
1869 const_equiv_class_label_t
const ecl
= (const_equiv_class_label_t
) p
;
1870 return ecl
->hashcode
;
1873 /* Equality function for two equiv_class_label_t's. */
1876 equiv_class_label_eq (const void *p1
, const void *p2
)
1878 const_equiv_class_label_t
const eql1
= (const_equiv_class_label_t
) p1
;
1879 const_equiv_class_label_t
const eql2
= (const_equiv_class_label_t
) p2
;
1880 return (eql1
->hashcode
== eql2
->hashcode
1881 && bitmap_equal_p (eql1
->labels
, eql2
->labels
));
1884 /* Lookup a equivalence class in TABLE by the bitmap of LABELS it
1888 equiv_class_lookup (htab_t table
, bitmap labels
)
1891 struct equiv_class_label ecl
;
1893 ecl
.labels
= labels
;
1894 ecl
.hashcode
= bitmap_hash (labels
);
1896 slot
= htab_find_slot_with_hash (table
, &ecl
,
1897 ecl
.hashcode
, NO_INSERT
);
1901 return ((equiv_class_label_t
) *slot
)->equivalence_class
;
1905 /* Add an equivalence class named EQUIVALENCE_CLASS with labels LABELS
1909 equiv_class_add (htab_t table
, unsigned int equivalence_class
,
1913 equiv_class_label_t ecl
= XNEW (struct equiv_class_label
);
1915 ecl
->labels
= labels
;
1916 ecl
->equivalence_class
= equivalence_class
;
1917 ecl
->hashcode
= bitmap_hash (labels
);
1919 slot
= htab_find_slot_with_hash (table
, ecl
,
1920 ecl
->hashcode
, INSERT
);
1921 gcc_assert (!*slot
);
1922 *slot
= (void *) ecl
;
1925 /* Perform offline variable substitution.
1927 This is a worst case quadratic time way of identifying variables
1928 that must have equivalent points-to sets, including those caused by
1929 static cycles, and single entry subgraphs, in the constraint graph.
1931 The technique is described in "Exploiting Pointer and Location
1932 Equivalence to Optimize Pointer Analysis. In the 14th International
1933 Static Analysis Symposium (SAS), August 2007." It is known as the
1934 "HU" algorithm, and is equivalent to value numbering the collapsed
1935 constraint graph including evaluating unions.
1937 The general method of finding equivalence classes is as follows:
1938 Add fake nodes (REF nodes) and edges for *a = b and a = *b constraints.
1939 Initialize all non-REF nodes to be direct nodes.
1940 For each constraint a = a U {b}, we set pts(a) = pts(a) u {fresh
1942 For each constraint containing the dereference, we also do the same
1945 We then compute SCC's in the graph and unify nodes in the same SCC,
1948 For each non-collapsed node x:
1949 Visit all unvisited explicit incoming edges.
1950 Ignoring all non-pointers, set pts(x) = Union of pts(a) for y
1952 Lookup the equivalence class for pts(x).
1953 If we found one, equivalence_class(x) = found class.
1954 Otherwise, equivalence_class(x) = new class, and new_class is
1955 added to the lookup table.
1957 All direct nodes with the same equivalence class can be replaced
1958 with a single representative node.
1959 All unlabeled nodes (label == 0) are not pointers and all edges
1960 involving them can be eliminated.
1961 We perform these optimizations during rewrite_constraints
1963 In addition to pointer equivalence class finding, we also perform
1964 location equivalence class finding. This is the set of variables
1965 that always appear together in points-to sets. We use this to
1966 compress the size of the points-to sets. */
1968 /* Current maximum pointer equivalence class id. */
1969 static int pointer_equiv_class
;
1971 /* Current maximum location equivalence class id. */
1972 static int location_equiv_class
;
1974 /* Recursive routine to find strongly connected components in GRAPH,
1975 and label it's nodes with DFS numbers. */
1978 condense_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
1982 unsigned int my_dfs
;
1984 gcc_assert (si
->node_mapping
[n
] == n
);
1985 SET_BIT (si
->visited
, n
);
1986 si
->dfs
[n
] = si
->current_index
++;
1987 my_dfs
= si
->dfs
[n
];
1989 /* Visit all the successors. */
1990 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->preds
[n
], 0, i
, bi
)
1992 unsigned int w
= si
->node_mapping
[i
];
1994 if (TEST_BIT (si
->deleted
, w
))
1997 if (!TEST_BIT (si
->visited
, w
))
1998 condense_visit (graph
, si
, w
);
2000 unsigned int t
= si
->node_mapping
[w
];
2001 unsigned int nnode
= si
->node_mapping
[n
];
2002 gcc_assert (nnode
== n
);
2004 if (si
->dfs
[t
] < si
->dfs
[nnode
])
2005 si
->dfs
[n
] = si
->dfs
[t
];
2009 /* Visit all the implicit predecessors. */
2010 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->implicit_preds
[n
], 0, i
, bi
)
2012 unsigned int w
= si
->node_mapping
[i
];
2014 if (TEST_BIT (si
->deleted
, w
))
2017 if (!TEST_BIT (si
->visited
, w
))
2018 condense_visit (graph
, si
, w
);
2020 unsigned int t
= si
->node_mapping
[w
];
2021 unsigned int nnode
= si
->node_mapping
[n
];
2022 gcc_assert (nnode
== n
);
2024 if (si
->dfs
[t
] < si
->dfs
[nnode
])
2025 si
->dfs
[n
] = si
->dfs
[t
];
2029 /* See if any components have been identified. */
2030 if (si
->dfs
[n
] == my_dfs
)
2032 while (VEC_length (unsigned, si
->scc_stack
) != 0
2033 && si
->dfs
[VEC_last (unsigned, si
->scc_stack
)] >= my_dfs
)
2035 unsigned int w
= VEC_pop (unsigned, si
->scc_stack
);
2036 si
->node_mapping
[w
] = n
;
2038 if (!TEST_BIT (graph
->direct_nodes
, w
))
2039 RESET_BIT (graph
->direct_nodes
, n
);
2041 /* Unify our nodes. */
2042 if (graph
->preds
[w
])
2044 if (!graph
->preds
[n
])
2045 graph
->preds
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2046 bitmap_ior_into (graph
->preds
[n
], graph
->preds
[w
]);
2048 if (graph
->implicit_preds
[w
])
2050 if (!graph
->implicit_preds
[n
])
2051 graph
->implicit_preds
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2052 bitmap_ior_into (graph
->implicit_preds
[n
],
2053 graph
->implicit_preds
[w
]);
2055 if (graph
->points_to
[w
])
2057 if (!graph
->points_to
[n
])
2058 graph
->points_to
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2059 bitmap_ior_into (graph
->points_to
[n
],
2060 graph
->points_to
[w
]);
2063 SET_BIT (si
->deleted
, n
);
2066 VEC_safe_push (unsigned, heap
, si
->scc_stack
, n
);
2069 /* Label pointer equivalences. */
2072 label_visit (constraint_graph_t graph
, struct scc_info
*si
, unsigned int n
)
2076 SET_BIT (si
->visited
, n
);
2078 if (!graph
->points_to
[n
])
2079 graph
->points_to
[n
] = BITMAP_ALLOC (&predbitmap_obstack
);
2081 /* Label and union our incoming edges's points to sets. */
2082 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->preds
[n
], 0, i
, bi
)
2084 unsigned int w
= si
->node_mapping
[i
];
2085 if (!TEST_BIT (si
->visited
, w
))
2086 label_visit (graph
, si
, w
);
2088 /* Skip unused edges */
2089 if (w
== n
|| graph
->pointer_label
[w
] == 0)
2092 if (graph
->points_to
[w
])
2093 bitmap_ior_into(graph
->points_to
[n
], graph
->points_to
[w
]);
2095 /* Indirect nodes get fresh variables. */
2096 if (!TEST_BIT (graph
->direct_nodes
, n
))
2097 bitmap_set_bit (graph
->points_to
[n
], FIRST_REF_NODE
+ n
);
2099 if (!bitmap_empty_p (graph
->points_to
[n
]))
2101 unsigned int label
= equiv_class_lookup (pointer_equiv_class_table
,
2102 graph
->points_to
[n
]);
2105 label
= pointer_equiv_class
++;
2106 equiv_class_add (pointer_equiv_class_table
,
2107 label
, graph
->points_to
[n
]);
2109 graph
->pointer_label
[n
] = label
;
2113 /* Perform offline variable substitution, discovering equivalence
2114 classes, and eliminating non-pointer variables. */
2116 static struct scc_info
*
2117 perform_var_substitution (constraint_graph_t graph
)
2120 unsigned int size
= graph
->size
;
2121 struct scc_info
*si
= init_scc_info (size
);
2123 bitmap_obstack_initialize (&iteration_obstack
);
2124 pointer_equiv_class_table
= htab_create (511, equiv_class_label_hash
,
2125 equiv_class_label_eq
, free
);
2126 location_equiv_class_table
= htab_create (511, equiv_class_label_hash
,
2127 equiv_class_label_eq
, free
);
2128 pointer_equiv_class
= 1;
2129 location_equiv_class
= 1;
2131 /* Condense the nodes, which means to find SCC's, count incoming
2132 predecessors, and unite nodes in SCC's. */
2133 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2134 if (!TEST_BIT (si
->visited
, si
->node_mapping
[i
]))
2135 condense_visit (graph
, si
, si
->node_mapping
[i
]);
2137 sbitmap_zero (si
->visited
);
2138 /* Actually the label the nodes for pointer equivalences */
2139 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2140 if (!TEST_BIT (si
->visited
, si
->node_mapping
[i
]))
2141 label_visit (graph
, si
, si
->node_mapping
[i
]);
2143 /* Calculate location equivalence labels. */
2144 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2151 if (!graph
->pointed_by
[i
])
2153 pointed_by
= BITMAP_ALLOC (&iteration_obstack
);
2155 /* Translate the pointed-by mapping for pointer equivalence
2157 EXECUTE_IF_SET_IN_BITMAP (graph
->pointed_by
[i
], 0, j
, bi
)
2159 bitmap_set_bit (pointed_by
,
2160 graph
->pointer_label
[si
->node_mapping
[j
]]);
2162 /* The original pointed_by is now dead. */
2163 BITMAP_FREE (graph
->pointed_by
[i
]);
2165 /* Look up the location equivalence label if one exists, or make
2167 label
= equiv_class_lookup (location_equiv_class_table
,
2171 label
= location_equiv_class
++;
2172 equiv_class_add (location_equiv_class_table
,
2177 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2178 fprintf (dump_file
, "Found location equivalence for node %s\n",
2179 get_varinfo (i
)->name
);
2180 BITMAP_FREE (pointed_by
);
2182 graph
->loc_label
[i
] = label
;
2186 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2187 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2189 bool direct_node
= TEST_BIT (graph
->direct_nodes
, i
);
2191 "Equivalence classes for %s node id %d:%s are pointer: %d"
2193 direct_node
? "Direct node" : "Indirect node", i
,
2194 get_varinfo (i
)->name
,
2195 graph
->pointer_label
[si
->node_mapping
[i
]],
2196 graph
->loc_label
[si
->node_mapping
[i
]]);
2199 /* Quickly eliminate our non-pointer variables. */
2201 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2203 unsigned int node
= si
->node_mapping
[i
];
2205 if (graph
->pointer_label
[node
] == 0)
2207 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2209 "%s is a non-pointer variable, eliminating edges.\n",
2210 get_varinfo (node
)->name
);
2211 stats
.nonpointer_vars
++;
2212 clear_edges_for_node (graph
, node
);
2219 /* Free information that was only necessary for variable
2223 free_var_substitution_info (struct scc_info
*si
)
2226 free (graph
->pointer_label
);
2227 free (graph
->loc_label
);
2228 free (graph
->pointed_by
);
2229 free (graph
->points_to
);
2230 free (graph
->eq_rep
);
2231 sbitmap_free (graph
->direct_nodes
);
2232 htab_delete (pointer_equiv_class_table
);
2233 htab_delete (location_equiv_class_table
);
2234 bitmap_obstack_release (&iteration_obstack
);
2237 /* Return an existing node that is equivalent to NODE, which has
2238 equivalence class LABEL, if one exists. Return NODE otherwise. */
2241 find_equivalent_node (constraint_graph_t graph
,
2242 unsigned int node
, unsigned int label
)
2244 /* If the address version of this variable is unused, we can
2245 substitute it for anything else with the same label.
2246 Otherwise, we know the pointers are equivalent, but not the
2247 locations, and we can unite them later. */
2249 if (!bitmap_bit_p (graph
->address_taken
, node
))
2251 gcc_assert (label
< graph
->size
);
2253 if (graph
->eq_rep
[label
] != -1)
2255 /* Unify the two variables since we know they are equivalent. */
2256 if (unite (graph
->eq_rep
[label
], node
))
2257 unify_nodes (graph
, graph
->eq_rep
[label
], node
, false);
2258 return graph
->eq_rep
[label
];
2262 graph
->eq_rep
[label
] = node
;
2263 graph
->pe_rep
[label
] = node
;
2268 gcc_assert (label
< graph
->size
);
2269 graph
->pe
[node
] = label
;
2270 if (graph
->pe_rep
[label
] == -1)
2271 graph
->pe_rep
[label
] = node
;
2277 /* Unite pointer equivalent but not location equivalent nodes in
2278 GRAPH. This may only be performed once variable substitution is
2282 unite_pointer_equivalences (constraint_graph_t graph
)
2286 /* Go through the pointer equivalences and unite them to their
2287 representative, if they aren't already. */
2288 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
2290 unsigned int label
= graph
->pe
[i
];
2293 int label_rep
= graph
->pe_rep
[label
];
2295 if (label_rep
== -1)
2298 label_rep
= find (label_rep
);
2299 if (label_rep
>= 0 && unite (label_rep
, find (i
)))
2300 unify_nodes (graph
, label_rep
, i
, false);
2305 /* Move complex constraints to the GRAPH nodes they belong to. */
2308 move_complex_constraints (constraint_graph_t graph
)
2313 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
2317 struct constraint_expr lhs
= c
->lhs
;
2318 struct constraint_expr rhs
= c
->rhs
;
2320 if (lhs
.type
== DEREF
)
2322 insert_into_complex (graph
, lhs
.var
, c
);
2324 else if (rhs
.type
== DEREF
)
2326 if (!(get_varinfo (lhs
.var
)->is_special_var
))
2327 insert_into_complex (graph
, rhs
.var
, c
);
2329 else if (rhs
.type
!= ADDRESSOF
&& lhs
.var
> anything_id
2330 && (lhs
.offset
!= 0 || rhs
.offset
!= 0))
2332 insert_into_complex (graph
, rhs
.var
, c
);
2339 /* Optimize and rewrite complex constraints while performing
2340 collapsing of equivalent nodes. SI is the SCC_INFO that is the
2341 result of perform_variable_substitution. */
2344 rewrite_constraints (constraint_graph_t graph
,
2345 struct scc_info
*si
)
2351 for (j
= 0; j
< graph
->size
; j
++)
2352 gcc_assert (find (j
) == j
);
2354 for (i
= 0; VEC_iterate (constraint_t
, constraints
, i
, c
); i
++)
2356 struct constraint_expr lhs
= c
->lhs
;
2357 struct constraint_expr rhs
= c
->rhs
;
2358 unsigned int lhsvar
= find (lhs
.var
);
2359 unsigned int rhsvar
= find (rhs
.var
);
2360 unsigned int lhsnode
, rhsnode
;
2361 unsigned int lhslabel
, rhslabel
;
2363 lhsnode
= si
->node_mapping
[lhsvar
];
2364 rhsnode
= si
->node_mapping
[rhsvar
];
2365 lhslabel
= graph
->pointer_label
[lhsnode
];
2366 rhslabel
= graph
->pointer_label
[rhsnode
];
2368 /* See if it is really a non-pointer variable, and if so, ignore
2372 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2375 fprintf (dump_file
, "%s is a non-pointer variable,"
2376 "ignoring constraint:",
2377 get_varinfo (lhs
.var
)->name
);
2378 dump_constraint (dump_file
, c
);
2380 VEC_replace (constraint_t
, constraints
, i
, NULL
);
2386 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
2389 fprintf (dump_file
, "%s is a non-pointer variable,"
2390 "ignoring constraint:",
2391 get_varinfo (rhs
.var
)->name
);
2392 dump_constraint (dump_file
, c
);
2394 VEC_replace (constraint_t
, constraints
, i
, NULL
);
2398 lhsvar
= find_equivalent_node (graph
, lhsvar
, lhslabel
);
2399 rhsvar
= find_equivalent_node (graph
, rhsvar
, rhslabel
);
2400 c
->lhs
.var
= lhsvar
;
2401 c
->rhs
.var
= rhsvar
;
2406 /* Eliminate indirect cycles involving NODE. Return true if NODE was
2407 part of an SCC, false otherwise. */
2410 eliminate_indirect_cycles (unsigned int node
)
2412 if (graph
->indirect_cycles
[node
] != -1
2413 && !bitmap_empty_p (get_varinfo (node
)->solution
))
2416 VEC(unsigned,heap
) *queue
= NULL
;
2418 unsigned int to
= find (graph
->indirect_cycles
[node
]);
2421 /* We can't touch the solution set and call unify_nodes
2422 at the same time, because unify_nodes is going to do
2423 bitmap unions into it. */
2425 EXECUTE_IF_SET_IN_BITMAP (get_varinfo (node
)->solution
, 0, i
, bi
)
2427 if (find (i
) == i
&& i
!= to
)
2430 VEC_safe_push (unsigned, heap
, queue
, i
);
2435 VEC_iterate (unsigned, queue
, queuepos
, i
);
2438 unify_nodes (graph
, to
, i
, true);
2440 VEC_free (unsigned, heap
, queue
);
2446 /* Solve the constraint graph GRAPH using our worklist solver.
2447 This is based on the PW* family of solvers from the "Efficient Field
2448 Sensitive Pointer Analysis for C" paper.
2449 It works by iterating over all the graph nodes, processing the complex
2450 constraints and propagating the copy constraints, until everything stops
2451 changed. This corresponds to steps 6-8 in the solving list given above. */
2454 solve_graph (constraint_graph_t graph
)
2456 unsigned int size
= graph
->size
;
2461 changed
= sbitmap_alloc (size
);
2462 sbitmap_zero (changed
);
2464 /* Mark all initial non-collapsed nodes as changed. */
2465 for (i
= 0; i
< size
; i
++)
2467 varinfo_t ivi
= get_varinfo (i
);
2468 if (find (i
) == i
&& !bitmap_empty_p (ivi
->solution
)
2469 && ((graph
->succs
[i
] && !bitmap_empty_p (graph
->succs
[i
]))
2470 || VEC_length (constraint_t
, graph
->complex[i
]) > 0))
2472 SET_BIT (changed
, i
);
2477 /* Allocate a bitmap to be used to store the changed bits. */
2478 pts
= BITMAP_ALLOC (&pta_obstack
);
2480 while (changed_count
> 0)
2483 struct topo_info
*ti
= init_topo_info ();
2486 bitmap_obstack_initialize (&iteration_obstack
);
2488 compute_topo_order (graph
, ti
);
2490 while (VEC_length (unsigned, ti
->topo_order
) != 0)
2493 i
= VEC_pop (unsigned, ti
->topo_order
);
2495 /* If this variable is not a representative, skip it. */
2499 /* In certain indirect cycle cases, we may merge this
2500 variable to another. */
2501 if (eliminate_indirect_cycles (i
) && find (i
) != i
)
2504 /* If the node has changed, we need to process the
2505 complex constraints and outgoing edges again. */
2506 if (TEST_BIT (changed
, i
))
2511 VEC(constraint_t
,heap
) *complex = graph
->complex[i
];
2512 bool solution_empty
;
2514 RESET_BIT (changed
, i
);
2517 /* Compute the changed set of solution bits. */
2518 bitmap_and_compl (pts
, get_varinfo (i
)->solution
,
2519 get_varinfo (i
)->oldsolution
);
2521 if (bitmap_empty_p (pts
))
2524 bitmap_ior_into (get_varinfo (i
)->oldsolution
, pts
);
2526 solution
= get_varinfo (i
)->solution
;
2527 solution_empty
= bitmap_empty_p (solution
);
2529 /* Process the complex constraints */
2530 for (j
= 0; VEC_iterate (constraint_t
, complex, j
, c
); j
++)
2532 /* XXX: This is going to unsort the constraints in
2533 some cases, which will occasionally add duplicate
2534 constraints during unification. This does not
2535 affect correctness. */
2536 c
->lhs
.var
= find (c
->lhs
.var
);
2537 c
->rhs
.var
= find (c
->rhs
.var
);
2539 /* The only complex constraint that can change our
2540 solution to non-empty, given an empty solution,
2541 is a constraint where the lhs side is receiving
2542 some set from elsewhere. */
2543 if (!solution_empty
|| c
->lhs
.type
!= DEREF
)
2544 do_complex_constraint (graph
, c
, pts
);
2547 solution_empty
= bitmap_empty_p (solution
);
2549 if (!solution_empty
)
2552 unsigned eff_escaped_id
= find (escaped_id
);
2554 /* Propagate solution to all successors. */
2555 EXECUTE_IF_IN_NONNULL_BITMAP (graph
->succs
[i
],
2561 unsigned int to
= find (j
);
2562 tmp
= get_varinfo (to
)->solution
;
2565 /* Don't try to propagate to ourselves. */
2569 /* If we propagate from ESCAPED use ESCAPED as
2571 if (i
== eff_escaped_id
)
2572 flag
= bitmap_set_bit (tmp
, escaped_id
);
2574 flag
= set_union_with_increment (tmp
, pts
, 0);
2578 get_varinfo (to
)->solution
= tmp
;
2579 if (!TEST_BIT (changed
, to
))
2581 SET_BIT (changed
, to
);
2589 free_topo_info (ti
);
2590 bitmap_obstack_release (&iteration_obstack
);
2594 sbitmap_free (changed
);
2595 bitmap_obstack_release (&oldpta_obstack
);
2598 /* Map from trees to variable infos. */
2599 static struct pointer_map_t
*vi_for_tree
;
2602 /* Insert ID as the variable id for tree T in the vi_for_tree map. */
2605 insert_vi_for_tree (tree t
, varinfo_t vi
)
2607 void **slot
= pointer_map_insert (vi_for_tree
, t
);
2609 gcc_assert (*slot
== NULL
);
2613 /* Find the variable info for tree T in VI_FOR_TREE. If T does not
2614 exist in the map, return NULL, otherwise, return the varinfo we found. */
2617 lookup_vi_for_tree (tree t
)
2619 void **slot
= pointer_map_contains (vi_for_tree
, t
);
2623 return (varinfo_t
) *slot
;
2626 /* Return a printable name for DECL */
2629 alias_get_name (tree decl
)
2631 const char *res
= get_name (decl
);
2633 int num_printed
= 0;
2642 if (TREE_CODE (decl
) == SSA_NAME
)
2644 num_printed
= asprintf (&temp
, "%s_%u",
2645 alias_get_name (SSA_NAME_VAR (decl
)),
2646 SSA_NAME_VERSION (decl
));
2648 else if (DECL_P (decl
))
2650 num_printed
= asprintf (&temp
, "D.%u", DECL_UID (decl
));
2652 if (num_printed
> 0)
2654 res
= ggc_strdup (temp
);
2660 /* Find the variable id for tree T in the map.
2661 If T doesn't exist in the map, create an entry for it and return it. */
2664 get_vi_for_tree (tree t
)
2666 void **slot
= pointer_map_contains (vi_for_tree
, t
);
2668 return get_varinfo (create_variable_info_for (t
, alias_get_name (t
)));
2670 return (varinfo_t
) *slot
;
2673 /* Get a scalar constraint expression for a new temporary variable. */
2675 static struct constraint_expr
2676 new_scalar_tmp_constraint_exp (const char *name
)
2678 struct constraint_expr tmp
;
2681 vi
= new_var_info (NULL_TREE
, name
);
2685 vi
->is_full_var
= 1;
2694 /* Get a constraint expression vector from an SSA_VAR_P node.
2695 If address_p is true, the result will be taken its address of. */
2698 get_constraint_for_ssa_var (tree t
, VEC(ce_s
, heap
) **results
, bool address_p
)
2700 struct constraint_expr cexpr
;
2703 /* We allow FUNCTION_DECLs here even though it doesn't make much sense. */
2704 gcc_assert (SSA_VAR_P (t
) || DECL_P (t
));
2706 /* For parameters, get at the points-to set for the actual parm
2708 if (TREE_CODE (t
) == SSA_NAME
2709 && TREE_CODE (SSA_NAME_VAR (t
)) == PARM_DECL
2710 && SSA_NAME_IS_DEFAULT_DEF (t
))
2712 get_constraint_for_ssa_var (SSA_NAME_VAR (t
), results
, address_p
);
2716 vi
= get_vi_for_tree (t
);
2718 cexpr
.type
= SCALAR
;
2720 /* If we determine the result is "anything", and we know this is readonly,
2721 say it points to readonly memory instead. */
2722 if (cexpr
.var
== anything_id
&& TREE_READONLY (t
))
2725 cexpr
.type
= ADDRESSOF
;
2726 cexpr
.var
= readonly_id
;
2729 /* If we are not taking the address of the constraint expr, add all
2730 sub-fiels of the variable as well. */
2733 for (; vi
; vi
= vi
->next
)
2736 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
2741 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
2744 /* Process constraint T, performing various simplifications and then
2745 adding it to our list of overall constraints. */
2748 process_constraint (constraint_t t
)
2750 struct constraint_expr rhs
= t
->rhs
;
2751 struct constraint_expr lhs
= t
->lhs
;
2753 gcc_assert (rhs
.var
< VEC_length (varinfo_t
, varmap
));
2754 gcc_assert (lhs
.var
< VEC_length (varinfo_t
, varmap
));
2756 /* If we didn't get any useful constraint from the lhs we get
2757 &ANYTHING as fallback from get_constraint_for. Deal with
2758 it here by turning it into *ANYTHING. */
2759 if (lhs
.type
== ADDRESSOF
2760 && lhs
.var
== anything_id
)
2763 /* ADDRESSOF on the lhs is invalid. */
2764 gcc_assert (lhs
.type
!= ADDRESSOF
);
2766 /* This can happen in our IR with things like n->a = *p */
2767 if (rhs
.type
== DEREF
&& lhs
.type
== DEREF
&& rhs
.var
!= anything_id
)
2769 /* Split into tmp = *rhs, *lhs = tmp */
2770 struct constraint_expr tmplhs
;
2771 tmplhs
= new_scalar_tmp_constraint_exp ("doubledereftmp");
2772 process_constraint (new_constraint (tmplhs
, rhs
));
2773 process_constraint (new_constraint (lhs
, tmplhs
));
2775 else if (rhs
.type
== ADDRESSOF
&& lhs
.type
== DEREF
)
2777 /* Split into tmp = &rhs, *lhs = tmp */
2778 struct constraint_expr tmplhs
;
2779 tmplhs
= new_scalar_tmp_constraint_exp ("derefaddrtmp");
2780 process_constraint (new_constraint (tmplhs
, rhs
));
2781 process_constraint (new_constraint (lhs
, tmplhs
));
2785 gcc_assert (rhs
.type
!= ADDRESSOF
|| rhs
.offset
== 0);
2786 VEC_safe_push (constraint_t
, heap
, constraints
, t
);
2790 /* Return true if T is a type that could contain pointers. */
2793 type_could_have_pointers (tree type
)
2795 if (POINTER_TYPE_P (type
))
2798 if (TREE_CODE (type
) == ARRAY_TYPE
)
2799 return type_could_have_pointers (TREE_TYPE (type
));
2801 return AGGREGATE_TYPE_P (type
);
2804 /* Return true if T is a variable of a type that could contain
2808 could_have_pointers (tree t
)
2810 return type_could_have_pointers (TREE_TYPE (t
));
2813 /* Return the position, in bits, of FIELD_DECL from the beginning of its
2816 static HOST_WIDE_INT
2817 bitpos_of_field (const tree fdecl
)
2820 if (!host_integerp (DECL_FIELD_OFFSET (fdecl
), 0)
2821 || !host_integerp (DECL_FIELD_BIT_OFFSET (fdecl
), 0))
2824 return (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (fdecl
)) * 8
2825 + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (fdecl
)));
2829 /* Get constraint expressions for offsetting PTR by OFFSET. Stores the
2830 resulting constraint expressions in *RESULTS. */
2833 get_constraint_for_ptr_offset (tree ptr
, tree offset
,
2834 VEC (ce_s
, heap
) **results
)
2836 struct constraint_expr
*c
;
2838 HOST_WIDE_INT rhsunitoffset
, rhsoffset
;
2840 /* If we do not do field-sensitive PTA adding offsets to pointers
2841 does not change the points-to solution. */
2842 if (!use_field_sensitive
)
2844 get_constraint_for (ptr
, results
);
2848 /* If the offset is not a non-negative integer constant that fits
2849 in a HOST_WIDE_INT, we have to fall back to a conservative
2850 solution which includes all sub-fields of all pointed-to
2851 variables of ptr. */
2852 if (offset
== NULL_TREE
2853 || !host_integerp (offset
, 0))
2854 rhsoffset
= UNKNOWN_OFFSET
;
2857 /* Make sure the bit-offset also fits. */
2858 rhsunitoffset
= TREE_INT_CST_LOW (offset
);
2859 rhsoffset
= rhsunitoffset
* BITS_PER_UNIT
;
2860 if (rhsunitoffset
!= rhsoffset
/ BITS_PER_UNIT
)
2861 rhsoffset
= UNKNOWN_OFFSET
;
2864 get_constraint_for (ptr
, results
);
2868 /* As we are eventually appending to the solution do not use
2869 VEC_iterate here. */
2870 n
= VEC_length (ce_s
, *results
);
2871 for (j
= 0; j
< n
; j
++)
2874 c
= VEC_index (ce_s
, *results
, j
);
2875 curr
= get_varinfo (c
->var
);
2877 if (c
->type
== ADDRESSOF
2878 /* If this varinfo represents a full variable just use it. */
2879 && curr
->is_full_var
)
2881 else if (c
->type
== ADDRESSOF
2882 /* If we do not know the offset add all subfields. */
2883 && rhsoffset
== UNKNOWN_OFFSET
)
2885 varinfo_t temp
= lookup_vi_for_tree (curr
->decl
);
2888 struct constraint_expr c2
;
2890 c2
.type
= ADDRESSOF
;
2892 if (c2
.var
!= c
->var
)
2893 VEC_safe_push (ce_s
, heap
, *results
, &c2
);
2898 else if (c
->type
== ADDRESSOF
)
2901 unsigned HOST_WIDE_INT offset
= curr
->offset
+ rhsoffset
;
2903 /* Search the sub-field which overlaps with the
2904 pointed-to offset. If the result is outside of the variable
2905 we have to provide a conservative result, as the variable is
2906 still reachable from the resulting pointer (even though it
2907 technically cannot point to anything). The last and first
2908 sub-fields are such conservative results.
2909 ??? If we always had a sub-field for &object + 1 then
2910 we could represent this in a more precise way. */
2912 && curr
->offset
< offset
)
2914 temp
= first_or_preceding_vi_for_offset (curr
, offset
);
2916 /* If the found variable is not exactly at the pointed to
2917 result, we have to include the next variable in the
2918 solution as well. Otherwise two increments by offset / 2
2919 do not result in the same or a conservative superset
2921 if (temp
->offset
!= offset
2922 && temp
->next
!= NULL
)
2924 struct constraint_expr c2
;
2925 c2
.var
= temp
->next
->id
;
2926 c2
.type
= ADDRESSOF
;
2928 VEC_safe_push (ce_s
, heap
, *results
, &c2
);
2934 c
->offset
= rhsoffset
;
2939 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
2940 If address_p is true the result will be taken its address of. */
2943 get_constraint_for_component_ref (tree t
, VEC(ce_s
, heap
) **results
,
2947 HOST_WIDE_INT bitsize
= -1;
2948 HOST_WIDE_INT bitmaxsize
= -1;
2949 HOST_WIDE_INT bitpos
;
2951 struct constraint_expr
*result
;
2953 /* Some people like to do cute things like take the address of
2956 while (!SSA_VAR_P (forzero
) && !CONSTANT_CLASS_P (forzero
))
2957 forzero
= TREE_OPERAND (forzero
, 0);
2959 if (CONSTANT_CLASS_P (forzero
) && integer_zerop (forzero
))
2961 struct constraint_expr temp
;
2964 temp
.var
= integer_id
;
2966 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
2970 t
= get_ref_base_and_extent (t
, &bitpos
, &bitsize
, &bitmaxsize
);
2972 /* Pretend to take the address of the base, we'll take care of
2973 adding the required subset of sub-fields below. */
2974 get_constraint_for_1 (t
, results
, true);
2975 gcc_assert (VEC_length (ce_s
, *results
) == 1);
2976 result
= VEC_last (ce_s
, *results
);
2978 if (result
->type
== SCALAR
2979 && get_varinfo (result
->var
)->is_full_var
)
2980 /* For single-field vars do not bother about the offset. */
2982 else if (result
->type
== SCALAR
)
2984 /* In languages like C, you can access one past the end of an
2985 array. You aren't allowed to dereference it, so we can
2986 ignore this constraint. When we handle pointer subtraction,
2987 we may have to do something cute here. */
2989 if ((unsigned HOST_WIDE_INT
)bitpos
< get_varinfo (result
->var
)->fullsize
2992 /* It's also not true that the constraint will actually start at the
2993 right offset, it may start in some padding. We only care about
2994 setting the constraint to the first actual field it touches, so
2996 struct constraint_expr cexpr
= *result
;
2998 VEC_pop (ce_s
, *results
);
3000 for (curr
= get_varinfo (cexpr
.var
); curr
; curr
= curr
->next
)
3002 if (ranges_overlap_p (curr
->offset
, curr
->size
,
3003 bitpos
, bitmaxsize
))
3005 cexpr
.var
= curr
->id
;
3006 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
3011 /* If we are going to take the address of this field then
3012 to be able to compute reachability correctly add at least
3013 the last field of the variable. */
3015 && VEC_length (ce_s
, *results
) == 0)
3017 curr
= get_varinfo (cexpr
.var
);
3018 while (curr
->next
!= NULL
)
3020 cexpr
.var
= curr
->id
;
3021 VEC_safe_push (ce_s
, heap
, *results
, &cexpr
);
3024 /* Assert that we found *some* field there. The user couldn't be
3025 accessing *only* padding. */
3026 /* Still the user could access one past the end of an array
3027 embedded in a struct resulting in accessing *only* padding. */
3028 gcc_assert (VEC_length (ce_s
, *results
) >= 1
3029 || ref_contains_array_ref (orig_t
));
3031 else if (bitmaxsize
== 0)
3033 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3034 fprintf (dump_file
, "Access to zero-sized part of variable,"
3038 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3039 fprintf (dump_file
, "Access to past the end of variable, ignoring\n");
3041 else if (result
->type
== DEREF
)
3043 /* If we do not know exactly where the access goes say so. Note
3044 that only for non-structure accesses we know that we access
3045 at most one subfiled of any variable. */
3047 || bitsize
!= bitmaxsize
3048 || AGGREGATE_TYPE_P (TREE_TYPE (orig_t
)))
3049 result
->offset
= UNKNOWN_OFFSET
;
3051 result
->offset
= bitpos
;
3053 else if (result
->type
== ADDRESSOF
)
3055 /* We can end up here for component references on a
3056 VIEW_CONVERT_EXPR <>(&foobar). */
3057 result
->type
= SCALAR
;
3058 result
->var
= anything_id
;
3066 /* Dereference the constraint expression CONS, and return the result.
3067 DEREF (ADDRESSOF) = SCALAR
3068 DEREF (SCALAR) = DEREF
3069 DEREF (DEREF) = (temp = DEREF1; result = DEREF(temp))
3070 This is needed so that we can handle dereferencing DEREF constraints. */
3073 do_deref (VEC (ce_s
, heap
) **constraints
)
3075 struct constraint_expr
*c
;
3078 for (i
= 0; VEC_iterate (ce_s
, *constraints
, i
, c
); i
++)
3080 if (c
->type
== SCALAR
)
3082 else if (c
->type
== ADDRESSOF
)
3084 else if (c
->type
== DEREF
)
3086 struct constraint_expr tmplhs
;
3087 tmplhs
= new_scalar_tmp_constraint_exp ("dereftmp");
3088 process_constraint (new_constraint (tmplhs
, *c
));
3089 c
->var
= tmplhs
.var
;
3096 static void get_constraint_for_1 (tree
, VEC (ce_s
, heap
) **, bool);
3098 /* Given a tree T, return the constraint expression for taking the
3102 get_constraint_for_address_of (tree t
, VEC (ce_s
, heap
) **results
)
3104 struct constraint_expr
*c
;
3107 get_constraint_for_1 (t
, results
, true);
3109 for (i
= 0; VEC_iterate (ce_s
, *results
, i
, c
); i
++)
3111 if (c
->type
== DEREF
)
3114 c
->type
= ADDRESSOF
;
3118 /* Given a tree T, return the constraint expression for it. */
3121 get_constraint_for_1 (tree t
, VEC (ce_s
, heap
) **results
, bool address_p
)
3123 struct constraint_expr temp
;
3125 /* x = integer is all glommed to a single variable, which doesn't
3126 point to anything by itself. That is, of course, unless it is an
3127 integer constant being treated as a pointer, in which case, we
3128 will return that this is really the addressof anything. This
3129 happens below, since it will fall into the default case. The only
3130 case we know something about an integer treated like a pointer is
3131 when it is the NULL pointer, and then we just say it points to
3134 Do not do that if -fno-delete-null-pointer-checks though, because
3135 in that case *NULL does not fail, so it _should_ alias *anything.
3136 It is not worth adding a new option or renaming the existing one,
3137 since this case is relatively obscure. */
3138 if (flag_delete_null_pointer_checks
3139 && ((TREE_CODE (t
) == INTEGER_CST
3140 && integer_zerop (t
))
3141 /* The only valid CONSTRUCTORs in gimple with pointer typed
3142 elements are zero-initializer. */
3143 || TREE_CODE (t
) == CONSTRUCTOR
))
3145 temp
.var
= nothing_id
;
3146 temp
.type
= ADDRESSOF
;
3148 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3152 /* String constants are read-only. */
3153 if (TREE_CODE (t
) == STRING_CST
)
3155 temp
.var
= readonly_id
;
3158 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3162 switch (TREE_CODE_CLASS (TREE_CODE (t
)))
3164 case tcc_expression
:
3166 switch (TREE_CODE (t
))
3169 get_constraint_for_address_of (TREE_OPERAND (t
, 0), results
);
3177 switch (TREE_CODE (t
))
3181 get_constraint_for_1 (TREE_OPERAND (t
, 0), results
, address_p
);
3186 case ARRAY_RANGE_REF
:
3188 get_constraint_for_component_ref (t
, results
, address_p
);
3190 case VIEW_CONVERT_EXPR
:
3191 get_constraint_for_1 (TREE_OPERAND (t
, 0), results
, address_p
);
3193 /* We are missing handling for TARGET_MEM_REF here. */
3198 case tcc_exceptional
:
3200 switch (TREE_CODE (t
))
3204 get_constraint_for_ssa_var (t
, results
, address_p
);
3211 case tcc_declaration
:
3213 get_constraint_for_ssa_var (t
, results
, address_p
);
3219 /* The default fallback is a constraint from anything. */
3220 temp
.type
= ADDRESSOF
;
3221 temp
.var
= anything_id
;
3223 VEC_safe_push (ce_s
, heap
, *results
, &temp
);
3226 /* Given a gimple tree T, return the constraint expression vector for it. */
3229 get_constraint_for (tree t
, VEC (ce_s
, heap
) **results
)
3231 gcc_assert (VEC_length (ce_s
, *results
) == 0);
3233 get_constraint_for_1 (t
, results
, false);
3237 /* Efficiently generates constraints from all entries in *RHSC to all
3238 entries in *LHSC. */
3241 process_all_all_constraints (VEC (ce_s
, heap
) *lhsc
, VEC (ce_s
, heap
) *rhsc
)
3243 struct constraint_expr
*lhsp
, *rhsp
;
3246 if (VEC_length (ce_s
, lhsc
) <= 1
3247 || VEC_length (ce_s
, rhsc
) <= 1)
3249 for (i
= 0; VEC_iterate (ce_s
, lhsc
, i
, lhsp
); ++i
)
3250 for (j
= 0; VEC_iterate (ce_s
, rhsc
, j
, rhsp
); ++j
)
3251 process_constraint (new_constraint (*lhsp
, *rhsp
));
3255 struct constraint_expr tmp
;
3256 tmp
= new_scalar_tmp_constraint_exp ("allalltmp");
3257 for (i
= 0; VEC_iterate (ce_s
, rhsc
, i
, rhsp
); ++i
)
3258 process_constraint (new_constraint (tmp
, *rhsp
));
3259 for (i
= 0; VEC_iterate (ce_s
, lhsc
, i
, lhsp
); ++i
)
3260 process_constraint (new_constraint (*lhsp
, tmp
));
3264 /* Handle aggregate copies by expanding into copies of the respective
3265 fields of the structures. */
3268 do_structure_copy (tree lhsop
, tree rhsop
)
3270 struct constraint_expr
*lhsp
, *rhsp
;
3271 VEC (ce_s
, heap
) *lhsc
= NULL
, *rhsc
= NULL
;
3274 get_constraint_for (lhsop
, &lhsc
);
3275 get_constraint_for (rhsop
, &rhsc
);
3276 lhsp
= VEC_index (ce_s
, lhsc
, 0);
3277 rhsp
= VEC_index (ce_s
, rhsc
, 0);
3278 if (lhsp
->type
== DEREF
3279 || (lhsp
->type
== ADDRESSOF
&& lhsp
->var
== anything_id
)
3280 || rhsp
->type
== DEREF
)
3281 process_all_all_constraints (lhsc
, rhsc
);
3282 else if (lhsp
->type
== SCALAR
3283 && (rhsp
->type
== SCALAR
3284 || rhsp
->type
== ADDRESSOF
))
3286 tree lhsbase
, rhsbase
;
3287 HOST_WIDE_INT lhssize
, lhsmaxsize
, lhsoffset
;
3288 HOST_WIDE_INT rhssize
, rhsmaxsize
, rhsoffset
;
3290 lhsbase
= get_ref_base_and_extent (lhsop
, &lhsoffset
,
3291 &lhssize
, &lhsmaxsize
);
3292 rhsbase
= get_ref_base_and_extent (rhsop
, &rhsoffset
,
3293 &rhssize
, &rhsmaxsize
);
3294 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
);)
3296 varinfo_t lhsv
, rhsv
;
3297 rhsp
= VEC_index (ce_s
, rhsc
, k
);
3298 lhsv
= get_varinfo (lhsp
->var
);
3299 rhsv
= get_varinfo (rhsp
->var
);
3300 if (lhsv
->may_have_pointers
3301 && ranges_overlap_p (lhsv
->offset
+ rhsoffset
, lhsv
->size
,
3302 rhsv
->offset
+ lhsoffset
, rhsv
->size
))
3303 process_constraint (new_constraint (*lhsp
, *rhsp
));
3304 if (lhsv
->offset
+ rhsoffset
+ lhsv
->size
3305 > rhsv
->offset
+ lhsoffset
+ rhsv
->size
)
3308 if (k
>= VEC_length (ce_s
, rhsc
))
3318 VEC_free (ce_s
, heap
, lhsc
);
3319 VEC_free (ce_s
, heap
, rhsc
);
3322 /* Create a constraint ID = OP. */
3325 make_constraint_to (unsigned id
, tree op
)
3327 VEC(ce_s
, heap
) *rhsc
= NULL
;
3328 struct constraint_expr
*c
;
3329 struct constraint_expr includes
;
3333 includes
.offset
= 0;
3334 includes
.type
= SCALAR
;
3336 get_constraint_for (op
, &rhsc
);
3337 for (j
= 0; VEC_iterate (ce_s
, rhsc
, j
, c
); j
++)
3338 process_constraint (new_constraint (includes
, *c
));
3339 VEC_free (ce_s
, heap
, rhsc
);
3342 /* Create a constraint ID = &FROM. */
3345 make_constraint_from (varinfo_t vi
, int from
)
3347 struct constraint_expr lhs
, rhs
;
3355 rhs
.type
= ADDRESSOF
;
3356 process_constraint (new_constraint (lhs
, rhs
));
3359 /* Create a constraint ID = FROM. */
3362 make_copy_constraint (varinfo_t vi
, int from
)
3364 struct constraint_expr lhs
, rhs
;
3373 process_constraint (new_constraint (lhs
, rhs
));
3376 /* Make constraints necessary to make OP escape. */
3379 make_escape_constraint (tree op
)
3381 make_constraint_to (escaped_id
, op
);
3384 /* Create a new artificial heap variable with NAME and make a
3385 constraint from it to LHS. Return the created variable. */
3388 make_constraint_from_heapvar (varinfo_t lhs
, const char *name
)
3391 tree heapvar
= heapvar_lookup (lhs
->decl
, lhs
->offset
);
3393 if (heapvar
== NULL_TREE
)
3396 heapvar
= create_tmp_var_raw (ptr_type_node
, name
);
3397 DECL_EXTERNAL (heapvar
) = 1;
3399 heapvar_insert (lhs
->decl
, lhs
->offset
, heapvar
);
3401 ann
= get_var_ann (heapvar
);
3402 ann
->is_heapvar
= 1;
3405 /* For global vars we need to add a heapvar to the list of referenced
3406 vars of a different function than it was created for originally. */
3407 if (gimple_referenced_vars (cfun
))
3408 add_referenced_var (heapvar
);
3410 vi
= new_var_info (heapvar
, name
);
3411 vi
->is_artificial_var
= true;
3412 vi
->is_heap_var
= true;
3413 vi
->is_unknown_size_var
= true;
3417 vi
->is_full_var
= true;
3418 insert_vi_for_tree (heapvar
, vi
);
3420 make_constraint_from (lhs
, vi
->id
);
3425 /* Create a new artificial heap variable with NAME and make a
3426 constraint from it to LHS. Set flags according to a tag used
3427 for tracking restrict pointers. */
3430 make_constraint_from_restrict (varinfo_t lhs
, const char *name
)
3433 vi
= make_constraint_from_heapvar (lhs
, name
);
3434 vi
->is_restrict_var
= 1;
3435 vi
->is_global_var
= 0;
3436 vi
->is_special_var
= 1;
3437 vi
->may_have_pointers
= 0;
3440 /* For non-IPA mode, generate constraints necessary for a call on the
3444 handle_rhs_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3446 struct constraint_expr rhsc
;
3449 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
3451 tree arg
= gimple_call_arg (stmt
, i
);
3453 /* Find those pointers being passed, and make sure they end up
3454 pointing to anything. */
3455 if (could_have_pointers (arg
))
3456 make_escape_constraint (arg
);
3459 /* The static chain escapes as well. */
3460 if (gimple_call_chain (stmt
))
3461 make_escape_constraint (gimple_call_chain (stmt
));
3463 /* And if we applied NRV the address of the return slot escapes as well. */
3464 if (gimple_call_return_slot_opt_p (stmt
)
3465 && gimple_call_lhs (stmt
) != NULL_TREE
3466 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt
))))
3468 VEC(ce_s
, heap
) *tmpc
= NULL
;
3469 struct constraint_expr lhsc
, *c
;
3470 get_constraint_for_address_of (gimple_call_lhs (stmt
), &tmpc
);
3471 lhsc
.var
= escaped_id
;
3474 for (i
= 0; VEC_iterate (ce_s
, tmpc
, i
, c
); ++i
)
3475 process_constraint (new_constraint (lhsc
, *c
));
3476 VEC_free(ce_s
, heap
, tmpc
);
3479 /* Regular functions return nonlocal memory. */
3480 rhsc
.var
= nonlocal_id
;
3483 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3486 /* For non-IPA mode, generate constraints necessary for a call
3487 that returns a pointer and assigns it to LHS. This simply makes
3488 the LHS point to global and escaped variables. */
3491 handle_lhs_call (tree lhs
, int flags
, VEC(ce_s
, heap
) *rhsc
)
3493 VEC(ce_s
, heap
) *lhsc
= NULL
;
3495 get_constraint_for (lhs
, &lhsc
);
3497 if (flags
& ECF_MALLOC
)
3500 vi
= make_constraint_from_heapvar (get_vi_for_tree (lhs
), "HEAP");
3501 /* We delay marking allocated storage global until we know if
3503 DECL_EXTERNAL (vi
->decl
) = 0;
3504 vi
->is_global_var
= 0;
3506 else if (VEC_length (ce_s
, rhsc
) > 0)
3508 /* If the store is to a global decl make sure to
3509 add proper escape constraints. */
3510 lhs
= get_base_address (lhs
);
3513 && is_global_var (lhs
))
3515 struct constraint_expr tmpc
;
3516 tmpc
.var
= escaped_id
;
3519 VEC_safe_push (ce_s
, heap
, lhsc
, &tmpc
);
3521 process_all_all_constraints (lhsc
, rhsc
);
3523 VEC_free (ce_s
, heap
, lhsc
);
3526 /* For non-IPA mode, generate constraints necessary for a call of a
3527 const function that returns a pointer in the statement STMT. */
3530 handle_const_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3532 struct constraint_expr rhsc
;
3535 /* Treat nested const functions the same as pure functions as far
3536 as the static chain is concerned. */
3537 if (gimple_call_chain (stmt
))
3539 make_constraint_to (callused_id
, gimple_call_chain (stmt
));
3540 rhsc
.var
= callused_id
;
3543 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3546 /* May return arguments. */
3547 for (k
= 0; k
< gimple_call_num_args (stmt
); ++k
)
3549 tree arg
= gimple_call_arg (stmt
, k
);
3551 if (could_have_pointers (arg
))
3553 VEC(ce_s
, heap
) *argc
= NULL
;
3555 struct constraint_expr
*argp
;
3556 get_constraint_for (arg
, &argc
);
3557 for (i
= 0; VEC_iterate (ce_s
, argc
, i
, argp
); ++i
)
3558 VEC_safe_push (ce_s
, heap
, *results
, argp
);
3559 VEC_free(ce_s
, heap
, argc
);
3563 /* May return addresses of globals. */
3564 rhsc
.var
= nonlocal_id
;
3566 rhsc
.type
= ADDRESSOF
;
3567 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3570 /* For non-IPA mode, generate constraints necessary for a call to a
3571 pure function in statement STMT. */
3574 handle_pure_call (gimple stmt
, VEC(ce_s
, heap
) **results
)
3576 struct constraint_expr rhsc
;
3578 bool need_callused
= false;
3580 /* Memory reached from pointer arguments is call-used. */
3581 for (i
= 0; i
< gimple_call_num_args (stmt
); ++i
)
3583 tree arg
= gimple_call_arg (stmt
, i
);
3585 if (could_have_pointers (arg
))
3587 make_constraint_to (callused_id
, arg
);
3588 need_callused
= true;
3592 /* The static chain is used as well. */
3593 if (gimple_call_chain (stmt
))
3595 make_constraint_to (callused_id
, gimple_call_chain (stmt
));
3596 need_callused
= true;
3599 /* Pure functions may return callused and nonlocal memory. */
3602 rhsc
.var
= callused_id
;
3605 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3607 rhsc
.var
= nonlocal_id
;
3610 VEC_safe_push (ce_s
, heap
, *results
, &rhsc
);
3613 /* Walk statement T setting up aliasing constraints according to the
3614 references found in T. This function is the main part of the
3615 constraint builder. AI points to auxiliary alias information used
3616 when building alias sets and computing alias grouping heuristics. */
3619 find_func_aliases (gimple origt
)
3622 VEC(ce_s
, heap
) *lhsc
= NULL
;
3623 VEC(ce_s
, heap
) *rhsc
= NULL
;
3624 struct constraint_expr
*c
;
3626 /* Now build constraints expressions. */
3627 if (gimple_code (t
) == GIMPLE_PHI
)
3629 gcc_assert (!AGGREGATE_TYPE_P (TREE_TYPE (gimple_phi_result (t
))));
3631 /* Only care about pointers and structures containing
3633 if (could_have_pointers (gimple_phi_result (t
)))
3638 /* For a phi node, assign all the arguments to
3640 get_constraint_for (gimple_phi_result (t
), &lhsc
);
3641 for (i
= 0; i
< gimple_phi_num_args (t
); i
++)
3644 tree strippedrhs
= PHI_ARG_DEF (t
, i
);
3646 STRIP_NOPS (strippedrhs
);
3647 rhstype
= TREE_TYPE (strippedrhs
);
3648 get_constraint_for (gimple_phi_arg_def (t
, i
), &rhsc
);
3650 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, c
); j
++)
3652 struct constraint_expr
*c2
;
3653 while (VEC_length (ce_s
, rhsc
) > 0)
3655 c2
= VEC_last (ce_s
, rhsc
);
3656 process_constraint (new_constraint (*c
, *c2
));
3657 VEC_pop (ce_s
, rhsc
);
3663 /* In IPA mode, we need to generate constraints to pass call
3664 arguments through their calls. There are two cases,
3665 either a GIMPLE_CALL returning a value, or just a plain
3666 GIMPLE_CALL when we are not.
3668 In non-ipa mode, we need to generate constraints for each
3669 pointer passed by address. */
3670 else if (is_gimple_call (t
))
3673 if ((fndecl
= gimple_call_fndecl (t
)) != NULL_TREE
3674 && DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
3675 /* ??? All builtins that are handled here need to be handled
3676 in the alias-oracle query functions explicitly! */
3677 switch (DECL_FUNCTION_CODE (fndecl
))
3679 /* All the following functions return a pointer to the same object
3680 as their first argument points to. The functions do not add
3681 to the ESCAPED solution. The functions make the first argument
3682 pointed to memory point to what the second argument pointed to
3683 memory points to. */
3684 case BUILT_IN_STRCPY
:
3685 case BUILT_IN_STRNCPY
:
3686 case BUILT_IN_BCOPY
:
3687 case BUILT_IN_MEMCPY
:
3688 case BUILT_IN_MEMMOVE
:
3689 case BUILT_IN_MEMPCPY
:
3690 case BUILT_IN_STPCPY
:
3691 case BUILT_IN_STPNCPY
:
3692 case BUILT_IN_STRCAT
:
3693 case BUILT_IN_STRNCAT
:
3695 tree res
= gimple_call_lhs (t
);
3696 tree dest
= gimple_call_arg (t
, 0);
3697 tree src
= gimple_call_arg (t
, 1);
3698 if (res
!= NULL_TREE
)
3700 get_constraint_for (res
, &lhsc
);
3701 if (DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_MEMPCPY
3702 || DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_STPCPY
3703 || DECL_FUNCTION_CODE (fndecl
) == BUILT_IN_STPNCPY
)
3704 get_constraint_for_ptr_offset (dest
, NULL_TREE
, &rhsc
);
3706 get_constraint_for (dest
, &rhsc
);
3707 process_all_all_constraints (lhsc
, rhsc
);
3708 VEC_free (ce_s
, heap
, lhsc
);
3709 VEC_free (ce_s
, heap
, rhsc
);
3711 get_constraint_for_ptr_offset (dest
, NULL_TREE
, &lhsc
);
3712 get_constraint_for_ptr_offset (src
, NULL_TREE
, &rhsc
);
3715 process_all_all_constraints (lhsc
, rhsc
);
3716 VEC_free (ce_s
, heap
, lhsc
);
3717 VEC_free (ce_s
, heap
, rhsc
);
3720 case BUILT_IN_MEMSET
:
3722 tree res
= gimple_call_lhs (t
);
3723 tree dest
= gimple_call_arg (t
, 0);
3726 struct constraint_expr ac
;
3727 if (res
!= NULL_TREE
)
3729 get_constraint_for (res
, &lhsc
);
3730 get_constraint_for (dest
, &rhsc
);
3731 process_all_all_constraints (lhsc
, rhsc
);
3732 VEC_free (ce_s
, heap
, lhsc
);
3733 VEC_free (ce_s
, heap
, rhsc
);
3735 get_constraint_for_ptr_offset (dest
, NULL_TREE
, &lhsc
);
3737 if (flag_delete_null_pointer_checks
3738 && integer_zerop (gimple_call_arg (t
, 1)))
3740 ac
.type
= ADDRESSOF
;
3741 ac
.var
= nothing_id
;
3746 ac
.var
= integer_id
;
3749 for (i
= 0; VEC_iterate (ce_s
, lhsc
, i
, lhsp
); ++i
)
3750 process_constraint (new_constraint (*lhsp
, ac
));
3751 VEC_free (ce_s
, heap
, lhsc
);
3754 /* All the following functions do not return pointers, do not
3755 modify the points-to sets of memory reachable from their
3756 arguments and do not add to the ESCAPED solution. */
3757 case BUILT_IN_SINCOS
:
3758 case BUILT_IN_SINCOSF
:
3759 case BUILT_IN_SINCOSL
:
3760 case BUILT_IN_FREXP
:
3761 case BUILT_IN_FREXPF
:
3762 case BUILT_IN_FREXPL
:
3763 case BUILT_IN_GAMMA_R
:
3764 case BUILT_IN_GAMMAF_R
:
3765 case BUILT_IN_GAMMAL_R
:
3766 case BUILT_IN_LGAMMA_R
:
3767 case BUILT_IN_LGAMMAF_R
:
3768 case BUILT_IN_LGAMMAL_R
:
3770 case BUILT_IN_MODFF
:
3771 case BUILT_IN_MODFL
:
3772 case BUILT_IN_REMQUO
:
3773 case BUILT_IN_REMQUOF
:
3774 case BUILT_IN_REMQUOL
:
3777 /* printf-style functions may have hooks to set pointers to
3778 point to somewhere into the generated string. Leave them
3779 for a later excercise... */
3781 /* Fallthru to general call handling. */;
3785 VEC(ce_s
, heap
) *rhsc
= NULL
;
3786 int flags
= gimple_call_flags (t
);
3788 /* Const functions can return their arguments and addresses
3789 of global memory but not of escaped memory. */
3790 if (flags
& (ECF_CONST
|ECF_NOVOPS
))
3792 if (gimple_call_lhs (t
)
3793 && could_have_pointers (gimple_call_lhs (t
)))
3794 handle_const_call (t
, &rhsc
);
3796 /* Pure functions can return addresses in and of memory
3797 reachable from their arguments, but they are not an escape
3798 point for reachable memory of their arguments. */
3799 else if (flags
& (ECF_PURE
|ECF_LOOPING_CONST_OR_PURE
))
3800 handle_pure_call (t
, &rhsc
);
3802 handle_rhs_call (t
, &rhsc
);
3803 if (gimple_call_lhs (t
)
3804 && could_have_pointers (gimple_call_lhs (t
)))
3805 handle_lhs_call (gimple_call_lhs (t
), flags
, rhsc
);
3806 VEC_free (ce_s
, heap
, rhsc
);
3816 lhsop
= gimple_call_lhs (t
);
3817 decl
= gimple_call_fndecl (t
);
3819 /* If we can directly resolve the function being called, do so.
3820 Otherwise, it must be some sort of indirect expression that
3821 we should still be able to handle. */
3823 fi
= get_vi_for_tree (decl
);
3826 decl
= gimple_call_fn (t
);
3827 fi
= get_vi_for_tree (decl
);
3830 /* Assign all the passed arguments to the appropriate incoming
3831 parameters of the function. */
3832 for (j
= 0; j
< gimple_call_num_args (t
); j
++)
3834 struct constraint_expr lhs
;
3835 struct constraint_expr
*rhsp
;
3836 tree arg
= gimple_call_arg (t
, j
);
3838 get_constraint_for (arg
, &rhsc
);
3839 if (TREE_CODE (decl
) != FUNCTION_DECL
)
3848 lhs
.var
= first_vi_for_offset (fi
, i
)->id
;
3851 while (VEC_length (ce_s
, rhsc
) != 0)
3853 rhsp
= VEC_last (ce_s
, rhsc
);
3854 process_constraint (new_constraint (lhs
, *rhsp
));
3855 VEC_pop (ce_s
, rhsc
);
3860 /* If we are returning a value, assign it to the result. */
3863 struct constraint_expr rhs
;
3864 struct constraint_expr
*lhsp
;
3867 get_constraint_for (lhsop
, &lhsc
);
3868 if (TREE_CODE (decl
) != FUNCTION_DECL
)
3877 rhs
.var
= first_vi_for_offset (fi
, i
)->id
;
3880 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); j
++)
3881 process_constraint (new_constraint (*lhsp
, rhs
));
3885 /* Otherwise, just a regular assignment statement. Only care about
3886 operations with pointer result, others are dealt with as escape
3887 points if they have pointer operands. */
3888 else if (is_gimple_assign (t
)
3889 && could_have_pointers (gimple_assign_lhs (t
)))
3891 /* Otherwise, just a regular assignment statement. */
3892 tree lhsop
= gimple_assign_lhs (t
);
3893 tree rhsop
= (gimple_num_ops (t
) == 2) ? gimple_assign_rhs1 (t
) : NULL
;
3895 if (rhsop
&& AGGREGATE_TYPE_P (TREE_TYPE (lhsop
)))
3896 do_structure_copy (lhsop
, rhsop
);
3899 struct constraint_expr temp
;
3900 get_constraint_for (lhsop
, &lhsc
);
3902 if (gimple_assign_rhs_code (t
) == POINTER_PLUS_EXPR
)
3903 get_constraint_for_ptr_offset (gimple_assign_rhs1 (t
),
3904 gimple_assign_rhs2 (t
), &rhsc
);
3905 else if ((CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t
))
3906 && !(POINTER_TYPE_P (gimple_expr_type (t
))
3907 && !POINTER_TYPE_P (TREE_TYPE (rhsop
))))
3908 || gimple_assign_single_p (t
))
3909 get_constraint_for (rhsop
, &rhsc
);
3912 temp
.type
= ADDRESSOF
;
3913 temp
.var
= anything_id
;
3915 VEC_safe_push (ce_s
, heap
, rhsc
, &temp
);
3917 process_all_all_constraints (lhsc
, rhsc
);
3919 /* If there is a store to a global variable the rhs escapes. */
3920 if ((lhsop
= get_base_address (lhsop
)) != NULL_TREE
3922 && is_global_var (lhsop
))
3923 make_escape_constraint (rhsop
);
3924 /* If this is a conversion of a non-restrict pointer to a
3925 restrict pointer track it with a new heapvar. */
3926 else if (gimple_assign_cast_p (t
)
3927 && POINTER_TYPE_P (TREE_TYPE (rhsop
))
3928 && POINTER_TYPE_P (TREE_TYPE (lhsop
))
3929 && !TYPE_RESTRICT (TREE_TYPE (rhsop
))
3930 && TYPE_RESTRICT (TREE_TYPE (lhsop
)))
3931 make_constraint_from_restrict (get_vi_for_tree (lhsop
),
3934 /* For conversions of pointers to non-pointers the pointer escapes. */
3935 else if (gimple_assign_cast_p (t
)
3936 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t
)))
3937 && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t
))))
3939 make_escape_constraint (gimple_assign_rhs1 (t
));
3941 /* Handle escapes through return. */
3942 else if (gimple_code (t
) == GIMPLE_RETURN
3943 && gimple_return_retval (t
) != NULL_TREE
3944 && could_have_pointers (gimple_return_retval (t
)))
3946 make_escape_constraint (gimple_return_retval (t
));
3948 /* Handle asms conservatively by adding escape constraints to everything. */
3949 else if (gimple_code (t
) == GIMPLE_ASM
)
3951 unsigned i
, noutputs
;
3952 const char **oconstraints
;
3953 const char *constraint
;
3954 bool allows_mem
, allows_reg
, is_inout
;
3956 noutputs
= gimple_asm_noutputs (t
);
3957 oconstraints
= XALLOCAVEC (const char *, noutputs
);
3959 for (i
= 0; i
< noutputs
; ++i
)
3961 tree link
= gimple_asm_output_op (t
, i
);
3962 tree op
= TREE_VALUE (link
);
3964 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
3965 oconstraints
[i
] = constraint
;
3966 parse_output_constraint (&constraint
, i
, 0, 0, &allows_mem
,
3967 &allows_reg
, &is_inout
);
3969 /* A memory constraint makes the address of the operand escape. */
3970 if (!allows_reg
&& allows_mem
)
3971 make_escape_constraint (build_fold_addr_expr (op
));
3973 /* The asm may read global memory, so outputs may point to
3974 any global memory. */
3975 if (op
&& could_have_pointers (op
))
3977 VEC(ce_s
, heap
) *lhsc
= NULL
;
3978 struct constraint_expr rhsc
, *lhsp
;
3980 get_constraint_for (op
, &lhsc
);
3981 rhsc
.var
= nonlocal_id
;
3984 for (j
= 0; VEC_iterate (ce_s
, lhsc
, j
, lhsp
); j
++)
3985 process_constraint (new_constraint (*lhsp
, rhsc
));
3986 VEC_free (ce_s
, heap
, lhsc
);
3989 for (i
= 0; i
< gimple_asm_ninputs (t
); ++i
)
3991 tree link
= gimple_asm_input_op (t
, i
);
3992 tree op
= TREE_VALUE (link
);
3994 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
3996 parse_input_constraint (&constraint
, 0, 0, noutputs
, 0, oconstraints
,
3997 &allows_mem
, &allows_reg
);
3999 /* A memory constraint makes the address of the operand escape. */
4000 if (!allows_reg
&& allows_mem
)
4001 make_escape_constraint (build_fold_addr_expr (op
));
4002 /* Strictly we'd only need the constraint to ESCAPED if
4003 the asm clobbers memory, otherwise using CALLUSED
4005 else if (op
&& could_have_pointers (op
))
4006 make_escape_constraint (op
);
4010 VEC_free (ce_s
, heap
, rhsc
);
4011 VEC_free (ce_s
, heap
, lhsc
);
4015 /* Find the first varinfo in the same variable as START that overlaps with
4016 OFFSET. Return NULL if we can't find one. */
4019 first_vi_for_offset (varinfo_t start
, unsigned HOST_WIDE_INT offset
)
4021 /* If the offset is outside of the variable, bail out. */
4022 if (offset
>= start
->fullsize
)
4025 /* If we cannot reach offset from start, lookup the first field
4026 and start from there. */
4027 if (start
->offset
> offset
)
4028 start
= lookup_vi_for_tree (start
->decl
);
4032 /* We may not find a variable in the field list with the actual
4033 offset when when we have glommed a structure to a variable.
4034 In that case, however, offset should still be within the size
4036 if (offset
>= start
->offset
4037 && offset
< (start
->offset
+ start
->size
))
4046 /* Find the first varinfo in the same variable as START that overlaps with
4047 OFFSET. If there is no such varinfo the varinfo directly preceding
4048 OFFSET is returned. */
4051 first_or_preceding_vi_for_offset (varinfo_t start
,
4052 unsigned HOST_WIDE_INT offset
)
4054 /* If we cannot reach offset from start, lookup the first field
4055 and start from there. */
4056 if (start
->offset
> offset
)
4057 start
= lookup_vi_for_tree (start
->decl
);
4059 /* We may not find a variable in the field list with the actual
4060 offset when when we have glommed a structure to a variable.
4061 In that case, however, offset should still be within the size
4063 If we got beyond the offset we look for return the field
4064 directly preceding offset which may be the last field. */
4066 && offset
>= start
->offset
4067 && !(offset
< (start
->offset
+ start
->size
)))
4068 start
= start
->next
;
4074 /* Insert the varinfo FIELD into the field list for BASE, at the front
4078 insert_into_field_list (varinfo_t base
, varinfo_t field
)
4080 varinfo_t prev
= base
;
4081 varinfo_t curr
= base
->next
;
4087 /* Insert the varinfo FIELD into the field list for BASE, ordered by
4091 insert_into_field_list_sorted (varinfo_t base
, varinfo_t field
)
4093 varinfo_t prev
= base
;
4094 varinfo_t curr
= base
->next
;
4105 if (field
->offset
<= curr
->offset
)
4110 field
->next
= prev
->next
;
4115 /* This structure is used during pushing fields onto the fieldstack
4116 to track the offset of the field, since bitpos_of_field gives it
4117 relative to its immediate containing type, and we want it relative
4118 to the ultimate containing object. */
4122 /* Offset from the base of the base containing object to this field. */
4123 HOST_WIDE_INT offset
;
4125 /* Size, in bits, of the field. */
4126 unsigned HOST_WIDE_INT size
;
4128 unsigned has_unknown_size
: 1;
4130 unsigned may_have_pointers
: 1;
4132 unsigned only_restrict_pointers
: 1;
4134 typedef struct fieldoff fieldoff_s
;
4136 DEF_VEC_O(fieldoff_s
);
4137 DEF_VEC_ALLOC_O(fieldoff_s
,heap
);
4139 /* qsort comparison function for two fieldoff's PA and PB */
4142 fieldoff_compare (const void *pa
, const void *pb
)
4144 const fieldoff_s
*foa
= (const fieldoff_s
*)pa
;
4145 const fieldoff_s
*fob
= (const fieldoff_s
*)pb
;
4146 unsigned HOST_WIDE_INT foasize
, fobsize
;
4148 if (foa
->offset
< fob
->offset
)
4150 else if (foa
->offset
> fob
->offset
)
4153 foasize
= foa
->size
;
4154 fobsize
= fob
->size
;
4155 if (foasize
< fobsize
)
4157 else if (foasize
> fobsize
)
4162 /* Sort a fieldstack according to the field offset and sizes. */
4164 sort_fieldstack (VEC(fieldoff_s
,heap
) *fieldstack
)
4166 qsort (VEC_address (fieldoff_s
, fieldstack
),
4167 VEC_length (fieldoff_s
, fieldstack
),
4168 sizeof (fieldoff_s
),
4172 /* Return true if V is a tree that we can have subvars for.
4173 Normally, this is any aggregate type. Also complex
4174 types which are not gimple registers can have subvars. */
4177 var_can_have_subvars (const_tree v
)
4179 /* Volatile variables should never have subvars. */
4180 if (TREE_THIS_VOLATILE (v
))
4183 /* Non decls or memory tags can never have subvars. */
4187 /* Aggregates without overlapping fields can have subvars. */
4188 if (TREE_CODE (TREE_TYPE (v
)) == RECORD_TYPE
)
4194 /* Given a TYPE, and a vector of field offsets FIELDSTACK, push all
4195 the fields of TYPE onto fieldstack, recording their offsets along
4198 OFFSET is used to keep track of the offset in this entire
4199 structure, rather than just the immediately containing structure.
4200 Returns the number of fields pushed. */
4203 push_fields_onto_fieldstack (tree type
, VEC(fieldoff_s
,heap
) **fieldstack
,
4204 HOST_WIDE_INT offset
)
4209 if (TREE_CODE (type
) != RECORD_TYPE
)
4212 /* If the vector of fields is growing too big, bail out early.
4213 Callers check for VEC_length <= MAX_FIELDS_FOR_FIELD_SENSITIVE, make
4215 if (VEC_length (fieldoff_s
, *fieldstack
) > MAX_FIELDS_FOR_FIELD_SENSITIVE
)
4218 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
4219 if (TREE_CODE (field
) == FIELD_DECL
)
4223 HOST_WIDE_INT foff
= bitpos_of_field (field
);
4225 if (!var_can_have_subvars (field
)
4226 || TREE_CODE (TREE_TYPE (field
)) == QUAL_UNION_TYPE
4227 || TREE_CODE (TREE_TYPE (field
)) == UNION_TYPE
)
4229 else if (!(pushed
= push_fields_onto_fieldstack
4230 (TREE_TYPE (field
), fieldstack
, offset
+ foff
))
4231 && (DECL_SIZE (field
)
4232 && !integer_zerop (DECL_SIZE (field
))))
4233 /* Empty structures may have actual size, like in C++. So
4234 see if we didn't push any subfields and the size is
4235 nonzero, push the field onto the stack. */
4240 fieldoff_s
*pair
= NULL
;
4241 bool has_unknown_size
= false;
4243 if (!VEC_empty (fieldoff_s
, *fieldstack
))
4244 pair
= VEC_last (fieldoff_s
, *fieldstack
);
4246 if (!DECL_SIZE (field
)
4247 || !host_integerp (DECL_SIZE (field
), 1))
4248 has_unknown_size
= true;
4250 /* If adjacent fields do not contain pointers merge them. */
4252 && !pair
->may_have_pointers
4253 && !could_have_pointers (field
)
4254 && !pair
->has_unknown_size
4255 && !has_unknown_size
4256 && pair
->offset
+ (HOST_WIDE_INT
)pair
->size
== offset
+ foff
)
4258 pair
= VEC_last (fieldoff_s
, *fieldstack
);
4259 pair
->size
+= TREE_INT_CST_LOW (DECL_SIZE (field
));
4263 pair
= VEC_safe_push (fieldoff_s
, heap
, *fieldstack
, NULL
);
4264 pair
->offset
= offset
+ foff
;
4265 pair
->has_unknown_size
= has_unknown_size
;
4266 if (!has_unknown_size
)
4267 pair
->size
= TREE_INT_CST_LOW (DECL_SIZE (field
));
4270 pair
->may_have_pointers
= could_have_pointers (field
);
4271 pair
->only_restrict_pointers
4272 = (!has_unknown_size
4273 && POINTER_TYPE_P (TREE_TYPE (field
))
4274 && TYPE_RESTRICT (TREE_TYPE (field
)));
4285 /* Count the number of arguments DECL has, and set IS_VARARGS to true
4286 if it is a varargs function. */
4289 count_num_arguments (tree decl
, bool *is_varargs
)
4294 for (t
= TYPE_ARG_TYPES (TREE_TYPE (decl
));
4298 if (TREE_VALUE (t
) == void_type_node
)
4308 /* Creation function node for DECL, using NAME, and return the index
4309 of the variable we've created for the function. */
4312 create_function_info_for (tree decl
, const char *name
)
4317 bool is_varargs
= false;
4319 /* Create the variable info. */
4321 vi
= new_var_info (decl
, name
);
4324 vi
->fullsize
= count_num_arguments (decl
, &is_varargs
) + 1;
4325 insert_vi_for_tree (vi
->decl
, vi
);
4329 /* If it's varargs, we don't know how many arguments it has, so we
4335 vi
->is_unknown_size_var
= true;
4339 arg
= DECL_ARGUMENTS (decl
);
4341 /* Set up variables for each argument. */
4342 for (i
= 1; i
< vi
->fullsize
; i
++)
4345 const char *newname
;
4347 tree argdecl
= decl
;
4352 asprintf (&tempname
, "%s.arg%d", name
, i
-1);
4353 newname
= ggc_strdup (tempname
);
4356 argvi
= new_var_info (argdecl
, newname
);
4359 argvi
->is_full_var
= true;
4360 argvi
->fullsize
= vi
->fullsize
;
4361 insert_into_field_list_sorted (vi
, argvi
);
4362 stats
.total_vars
++;
4365 insert_vi_for_tree (arg
, argvi
);
4366 arg
= TREE_CHAIN (arg
);
4370 /* Create a variable for the return var. */
4371 if (DECL_RESULT (decl
) != NULL
4372 || !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl
))))
4375 const char *newname
;
4377 tree resultdecl
= decl
;
4381 if (DECL_RESULT (decl
))
4382 resultdecl
= DECL_RESULT (decl
);
4384 asprintf (&tempname
, "%s.result", name
);
4385 newname
= ggc_strdup (tempname
);
4388 resultvi
= new_var_info (resultdecl
, newname
);
4389 resultvi
->offset
= i
;
4391 resultvi
->fullsize
= vi
->fullsize
;
4392 resultvi
->is_full_var
= true;
4393 insert_into_field_list_sorted (vi
, resultvi
);
4394 stats
.total_vars
++;
4395 if (DECL_RESULT (decl
))
4396 insert_vi_for_tree (DECL_RESULT (decl
), resultvi
);
4403 /* Return true if FIELDSTACK contains fields that overlap.
4404 FIELDSTACK is assumed to be sorted by offset. */
4407 check_for_overlaps (VEC (fieldoff_s
,heap
) *fieldstack
)
4409 fieldoff_s
*fo
= NULL
;
4411 HOST_WIDE_INT lastoffset
= -1;
4413 for (i
= 0; VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
); i
++)
4415 if (fo
->offset
== lastoffset
)
4417 lastoffset
= fo
->offset
;
4422 /* Create a varinfo structure for NAME and DECL, and add it to VARMAP.
4423 This will also create any varinfo structures necessary for fields
4427 create_variable_info_for (tree decl
, const char *name
)
4430 tree decl_type
= TREE_TYPE (decl
);
4431 tree declsize
= DECL_P (decl
) ? DECL_SIZE (decl
) : TYPE_SIZE (decl_type
);
4432 VEC (fieldoff_s
,heap
) *fieldstack
= NULL
;
4434 if (TREE_CODE (decl
) == FUNCTION_DECL
&& in_ipa_mode
)
4435 return create_function_info_for (decl
, name
);
4437 if (var_can_have_subvars (decl
) && use_field_sensitive
)
4438 push_fields_onto_fieldstack (decl_type
, &fieldstack
, 0);
4440 /* If the variable doesn't have subvars, we may end up needing to
4441 sort the field list and create fake variables for all the
4443 vi
= new_var_info (decl
, name
);
4445 vi
->may_have_pointers
= could_have_pointers (decl
);
4447 || !host_integerp (declsize
, 1))
4449 vi
->is_unknown_size_var
= true;
4455 vi
->fullsize
= TREE_INT_CST_LOW (declsize
);
4456 vi
->size
= vi
->fullsize
;
4459 insert_vi_for_tree (vi
->decl
, vi
);
4460 if (vi
->is_global_var
4461 && (!flag_whole_program
|| !in_ipa_mode
)
4462 && vi
->may_have_pointers
)
4464 if (POINTER_TYPE_P (TREE_TYPE (decl
))
4465 && TYPE_RESTRICT (TREE_TYPE (decl
)))
4466 make_constraint_from_restrict (vi
, "GLOBAL_RESTRICT");
4467 make_copy_constraint (vi
, nonlocal_id
);
4471 if (use_field_sensitive
4472 && !vi
->is_unknown_size_var
4473 && var_can_have_subvars (decl
)
4474 && VEC_length (fieldoff_s
, fieldstack
) > 1
4475 && VEC_length (fieldoff_s
, fieldstack
) <= MAX_FIELDS_FOR_FIELD_SENSITIVE
)
4477 fieldoff_s
*fo
= NULL
;
4478 bool notokay
= false;
4481 for (i
= 0; !notokay
&& VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
); i
++)
4483 if (fo
->has_unknown_size
4491 /* We can't sort them if we have a field with a variable sized type,
4492 which will make notokay = true. In that case, we are going to return
4493 without creating varinfos for the fields anyway, so sorting them is a
4497 sort_fieldstack (fieldstack
);
4498 /* Due to some C++ FE issues, like PR 22488, we might end up
4499 what appear to be overlapping fields even though they,
4500 in reality, do not overlap. Until the C++ FE is fixed,
4501 we will simply disable field-sensitivity for these cases. */
4502 notokay
= check_for_overlaps (fieldstack
);
4506 if (VEC_length (fieldoff_s
, fieldstack
) != 0)
4507 fo
= VEC_index (fieldoff_s
, fieldstack
, 0);
4509 if (fo
== NULL
|| notokay
)
4511 vi
->is_unknown_size_var
= 1;
4514 vi
->is_full_var
= true;
4515 VEC_free (fieldoff_s
, heap
, fieldstack
);
4519 vi
->size
= fo
->size
;
4520 vi
->offset
= fo
->offset
;
4521 vi
->may_have_pointers
= fo
->may_have_pointers
;
4522 if (vi
->is_global_var
4523 && (!flag_whole_program
|| !in_ipa_mode
)
4524 && vi
->may_have_pointers
)
4526 if (fo
->only_restrict_pointers
)
4527 make_constraint_from_restrict (vi
, "GLOBAL_RESTRICT");
4529 for (i
= VEC_length (fieldoff_s
, fieldstack
) - 1;
4530 i
>= 1 && VEC_iterate (fieldoff_s
, fieldstack
, i
, fo
);
4534 const char *newname
= "NULL";
4539 asprintf (&tempname
, "%s." HOST_WIDE_INT_PRINT_DEC
4540 "+" HOST_WIDE_INT_PRINT_DEC
,
4541 vi
->name
, fo
->offset
, fo
->size
);
4542 newname
= ggc_strdup (tempname
);
4545 newvi
= new_var_info (decl
, newname
);
4546 newvi
->offset
= fo
->offset
;
4547 newvi
->size
= fo
->size
;
4548 newvi
->fullsize
= vi
->fullsize
;
4549 newvi
->may_have_pointers
= fo
->may_have_pointers
;
4550 insert_into_field_list (vi
, newvi
);
4551 if ((newvi
->is_global_var
|| TREE_CODE (decl
) == PARM_DECL
)
4552 && newvi
->may_have_pointers
)
4554 if (fo
->only_restrict_pointers
)
4555 make_constraint_from_restrict (newvi
, "GLOBAL_RESTRICT");
4556 if (newvi
->is_global_var
&& !in_ipa_mode
)
4557 make_copy_constraint (newvi
, nonlocal_id
);
4564 vi
->is_full_var
= true;
4566 VEC_free (fieldoff_s
, heap
, fieldstack
);
4571 /* Print out the points-to solution for VAR to FILE. */
4574 dump_solution_for_var (FILE *file
, unsigned int var
)
4576 varinfo_t vi
= get_varinfo (var
);
4580 if (find (var
) != var
)
4582 varinfo_t vipt
= get_varinfo (find (var
));
4583 fprintf (file
, "%s = same as %s\n", vi
->name
, vipt
->name
);
4587 fprintf (file
, "%s = { ", vi
->name
);
4588 EXECUTE_IF_SET_IN_BITMAP (vi
->solution
, 0, i
, bi
)
4590 fprintf (file
, "%s ", get_varinfo (i
)->name
);
4592 fprintf (file
, "}\n");
4596 /* Print the points-to solution for VAR to stdout. */
4599 debug_solution_for_var (unsigned int var
)
4601 dump_solution_for_var (stdout
, var
);
4604 /* Create varinfo structures for all of the variables in the
4605 function for intraprocedural mode. */
4608 intra_create_variable_infos (void)
4612 /* For each incoming pointer argument arg, create the constraint ARG
4613 = NONLOCAL or a dummy variable if flag_argument_noalias is set. */
4614 for (t
= DECL_ARGUMENTS (current_function_decl
); t
; t
= TREE_CHAIN (t
))
4618 if (!could_have_pointers (t
))
4621 /* For restrict qualified pointers to objects passed by
4622 reference build a real representative for the pointed-to object. */
4623 if (DECL_BY_REFERENCE (t
)
4624 && POINTER_TYPE_P (TREE_TYPE (t
))
4625 && TYPE_RESTRICT (TREE_TYPE (t
)))
4627 struct constraint_expr lhsc
, rhsc
;
4629 tree heapvar
= heapvar_lookup (t
, 0);
4630 if (heapvar
== NULL_TREE
)
4633 heapvar
= create_tmp_var_raw (TREE_TYPE (TREE_TYPE (t
)),
4635 DECL_EXTERNAL (heapvar
) = 1;
4636 heapvar_insert (t
, 0, heapvar
);
4637 ann
= get_var_ann (heapvar
);
4638 ann
->is_heapvar
= 1;
4640 if (gimple_referenced_vars (cfun
))
4641 add_referenced_var (heapvar
);
4642 lhsc
.var
= get_vi_for_tree (t
)->id
;
4645 rhsc
.var
= (vi
= get_vi_for_tree (heapvar
))->id
;
4646 rhsc
.type
= ADDRESSOF
;
4648 process_constraint (new_constraint (lhsc
, rhsc
));
4649 vi
->is_restrict_var
= 1;
4653 for (p
= get_vi_for_tree (t
); p
; p
= p
->next
)
4654 if (p
->may_have_pointers
)
4655 make_constraint_from (p
, nonlocal_id
);
4656 if (POINTER_TYPE_P (TREE_TYPE (t
))
4657 && TYPE_RESTRICT (TREE_TYPE (t
)))
4658 make_constraint_from_restrict (get_vi_for_tree (t
), "PARM_RESTRICT");
4661 /* Add a constraint for a result decl that is passed by reference. */
4662 if (DECL_RESULT (cfun
->decl
)
4663 && DECL_BY_REFERENCE (DECL_RESULT (cfun
->decl
)))
4665 varinfo_t p
, result_vi
= get_vi_for_tree (DECL_RESULT (cfun
->decl
));
4667 for (p
= result_vi
; p
; p
= p
->next
)
4668 make_constraint_from (p
, nonlocal_id
);
4671 /* Add a constraint for the incoming static chain parameter. */
4672 if (cfun
->static_chain_decl
!= NULL_TREE
)
4674 varinfo_t p
, chain_vi
= get_vi_for_tree (cfun
->static_chain_decl
);
4676 for (p
= chain_vi
; p
; p
= p
->next
)
4677 make_constraint_from (p
, nonlocal_id
);
4681 /* Structure used to put solution bitmaps in a hashtable so they can
4682 be shared among variables with the same points-to set. */
4684 typedef struct shared_bitmap_info
4688 } *shared_bitmap_info_t
;
4689 typedef const struct shared_bitmap_info
*const_shared_bitmap_info_t
;
4691 static htab_t shared_bitmap_table
;
4693 /* Hash function for a shared_bitmap_info_t */
4696 shared_bitmap_hash (const void *p
)
4698 const_shared_bitmap_info_t
const bi
= (const_shared_bitmap_info_t
) p
;
4699 return bi
->hashcode
;
4702 /* Equality function for two shared_bitmap_info_t's. */
4705 shared_bitmap_eq (const void *p1
, const void *p2
)
4707 const_shared_bitmap_info_t
const sbi1
= (const_shared_bitmap_info_t
) p1
;
4708 const_shared_bitmap_info_t
const sbi2
= (const_shared_bitmap_info_t
) p2
;
4709 return bitmap_equal_p (sbi1
->pt_vars
, sbi2
->pt_vars
);
4712 /* Lookup a bitmap in the shared bitmap hashtable, and return an already
4713 existing instance if there is one, NULL otherwise. */
4716 shared_bitmap_lookup (bitmap pt_vars
)
4719 struct shared_bitmap_info sbi
;
4721 sbi
.pt_vars
= pt_vars
;
4722 sbi
.hashcode
= bitmap_hash (pt_vars
);
4724 slot
= htab_find_slot_with_hash (shared_bitmap_table
, &sbi
,
4725 sbi
.hashcode
, NO_INSERT
);
4729 return ((shared_bitmap_info_t
) *slot
)->pt_vars
;
4733 /* Add a bitmap to the shared bitmap hashtable. */
4736 shared_bitmap_add (bitmap pt_vars
)
4739 shared_bitmap_info_t sbi
= XNEW (struct shared_bitmap_info
);
4741 sbi
->pt_vars
= pt_vars
;
4742 sbi
->hashcode
= bitmap_hash (pt_vars
);
4744 slot
= htab_find_slot_with_hash (shared_bitmap_table
, sbi
,
4745 sbi
->hashcode
, INSERT
);
4746 gcc_assert (!*slot
);
4747 *slot
= (void *) sbi
;
4751 /* Set bits in INTO corresponding to the variable uids in solution set FROM. */
4754 set_uids_in_ptset (bitmap into
, bitmap from
, struct pt_solution
*pt
)
4759 EXECUTE_IF_SET_IN_BITMAP (from
, 0, i
, bi
)
4761 varinfo_t vi
= get_varinfo (i
);
4763 /* The only artificial variables that are allowed in a may-alias
4764 set are heap variables. */
4765 if (vi
->is_artificial_var
&& !vi
->is_heap_var
)
4768 if (TREE_CODE (vi
->decl
) == VAR_DECL
4769 || TREE_CODE (vi
->decl
) == PARM_DECL
4770 || TREE_CODE (vi
->decl
) == RESULT_DECL
)
4772 /* Add the decl to the points-to set. Note that the points-to
4773 set contains global variables. */
4774 bitmap_set_bit (into
, DECL_UID (vi
->decl
));
4775 if (vi
->is_global_var
)
4776 pt
->vars_contains_global
= true;
4782 static bool have_alias_info
= false;
4784 /* Compute the points-to solution *PT for the variable VI. */
4787 find_what_var_points_to (varinfo_t vi
, struct pt_solution
*pt
)
4791 bitmap finished_solution
;
4794 memset (pt
, 0, sizeof (struct pt_solution
));
4796 /* This variable may have been collapsed, let's get the real
4798 vi
= get_varinfo (find (vi
->id
));
4800 /* Translate artificial variables into SSA_NAME_PTR_INFO
4802 EXECUTE_IF_SET_IN_BITMAP (vi
->solution
, 0, i
, bi
)
4804 varinfo_t vi
= get_varinfo (i
);
4806 if (vi
->is_artificial_var
)
4808 if (vi
->id
== nothing_id
)
4810 else if (vi
->id
== escaped_id
)
4812 else if (vi
->id
== callused_id
)
4814 else if (vi
->id
== nonlocal_id
)
4816 else if (vi
->is_heap_var
)
4817 /* We represent heapvars in the points-to set properly. */
4819 else if (vi
->id
== readonly_id
)
4822 else if (vi
->id
== anything_id
4823 || vi
->id
== integer_id
)
4826 if (vi
->is_restrict_var
)
4827 pt
->vars_contains_restrict
= true;
4830 /* Instead of doing extra work, simply do not create
4831 elaborate points-to information for pt_anything pointers. */
4833 && (vi
->is_artificial_var
4834 || !pt
->vars_contains_restrict
))
4837 /* Share the final set of variables when possible. */
4838 finished_solution
= BITMAP_GGC_ALLOC ();
4839 stats
.points_to_sets_created
++;
4841 set_uids_in_ptset (finished_solution
, vi
->solution
, pt
);
4842 result
= shared_bitmap_lookup (finished_solution
);
4845 shared_bitmap_add (finished_solution
);
4846 pt
->vars
= finished_solution
;
4851 bitmap_clear (finished_solution
);
4855 /* Given a pointer variable P, fill in its points-to set. */
4858 find_what_p_points_to (tree p
)
4860 struct ptr_info_def
*pi
;
4864 /* For parameters, get at the points-to set for the actual parm
4866 if (TREE_CODE (p
) == SSA_NAME
4867 && TREE_CODE (SSA_NAME_VAR (p
)) == PARM_DECL
4868 && SSA_NAME_IS_DEFAULT_DEF (p
))
4869 lookup_p
= SSA_NAME_VAR (p
);
4871 vi
= lookup_vi_for_tree (lookup_p
);
4875 pi
= get_ptr_info (p
);
4876 find_what_var_points_to (vi
, &pi
->pt
);
4880 /* Query statistics for points-to solutions. */
4883 unsigned HOST_WIDE_INT pt_solution_includes_may_alias
;
4884 unsigned HOST_WIDE_INT pt_solution_includes_no_alias
;
4885 unsigned HOST_WIDE_INT pt_solutions_intersect_may_alias
;
4886 unsigned HOST_WIDE_INT pt_solutions_intersect_no_alias
;
4890 dump_pta_stats (FILE *s
)
4892 fprintf (s
, "\nPTA query stats:\n");
4893 fprintf (s
, " pt_solution_includes: "
4894 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
4895 HOST_WIDE_INT_PRINT_DEC
" queries\n",
4896 pta_stats
.pt_solution_includes_no_alias
,
4897 pta_stats
.pt_solution_includes_no_alias
4898 + pta_stats
.pt_solution_includes_may_alias
);
4899 fprintf (s
, " pt_solutions_intersect: "
4900 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
4901 HOST_WIDE_INT_PRINT_DEC
" queries\n",
4902 pta_stats
.pt_solutions_intersect_no_alias
,
4903 pta_stats
.pt_solutions_intersect_no_alias
4904 + pta_stats
.pt_solutions_intersect_may_alias
);
4908 /* Reset the points-to solution *PT to a conservative default
4909 (point to anything). */
4912 pt_solution_reset (struct pt_solution
*pt
)
4914 memset (pt
, 0, sizeof (struct pt_solution
));
4915 pt
->anything
= true;
4918 /* Set the points-to solution *PT to point only to the variables
4922 pt_solution_set (struct pt_solution
*pt
, bitmap vars
)
4927 memset (pt
, 0, sizeof (struct pt_solution
));
4929 EXECUTE_IF_SET_IN_BITMAP (vars
, 0, i
, bi
)
4931 tree var
= referenced_var_lookup (i
);
4932 if (is_global_var (var
))
4934 pt
->vars_contains_global
= true;
4940 /* Return true if the points-to solution *PT is empty. */
4943 pt_solution_empty_p (struct pt_solution
*pt
)
4950 && !bitmap_empty_p (pt
->vars
))
4953 /* If the solution includes ESCAPED, check if that is empty. */
4955 && !pt_solution_empty_p (&cfun
->gimple_df
->escaped
))
4961 /* Return true if the points-to solution *PT includes global memory. */
4964 pt_solution_includes_global (struct pt_solution
*pt
)
4968 || pt
->vars_contains_global
)
4972 return pt_solution_includes_global (&cfun
->gimple_df
->escaped
);
4977 /* Return true if the points-to solution *PT includes the variable
4978 declaration DECL. */
4981 pt_solution_includes_1 (struct pt_solution
*pt
, const_tree decl
)
4987 && is_global_var (decl
))
4991 && bitmap_bit_p (pt
->vars
, DECL_UID (decl
)))
4994 /* If the solution includes ESCAPED, check it. */
4996 && pt_solution_includes_1 (&cfun
->gimple_df
->escaped
, decl
))
5003 pt_solution_includes (struct pt_solution
*pt
, const_tree decl
)
5005 bool res
= pt_solution_includes_1 (pt
, decl
);
5007 ++pta_stats
.pt_solution_includes_may_alias
;
5009 ++pta_stats
.pt_solution_includes_no_alias
;
5013 /* Return true if both points-to solutions PT1 and PT2 have a non-empty
5017 pt_solutions_intersect_1 (struct pt_solution
*pt1
, struct pt_solution
*pt2
)
5019 if (pt1
->anything
|| pt2
->anything
)
5022 /* If either points to unknown global memory and the other points to
5023 any global memory they alias. */
5026 || pt2
->vars_contains_global
))
5028 && pt1
->vars_contains_global
))
5031 /* Check the escaped solution if required. */
5032 if ((pt1
->escaped
|| pt2
->escaped
)
5033 && !pt_solution_empty_p (&cfun
->gimple_df
->escaped
))
5035 /* If both point to escaped memory and that solution
5036 is not empty they alias. */
5037 if (pt1
->escaped
&& pt2
->escaped
)
5040 /* If either points to escaped memory see if the escaped solution
5041 intersects with the other. */
5043 && pt_solutions_intersect_1 (&cfun
->gimple_df
->escaped
, pt2
))
5045 && pt_solutions_intersect_1 (&cfun
->gimple_df
->escaped
, pt1
)))
5049 /* Now both pointers alias if their points-to solution intersects. */
5052 && bitmap_intersect_p (pt1
->vars
, pt2
->vars
));
5056 pt_solutions_intersect (struct pt_solution
*pt1
, struct pt_solution
*pt2
)
5058 bool res
= pt_solutions_intersect_1 (pt1
, pt2
);
5060 ++pta_stats
.pt_solutions_intersect_may_alias
;
5062 ++pta_stats
.pt_solutions_intersect_no_alias
;
5066 /* Return true if both points-to solutions PT1 and PT2 for two restrict
5067 qualified pointers are possibly based on the same pointer. */
5070 pt_solutions_same_restrict_base (struct pt_solution
*pt1
,
5071 struct pt_solution
*pt2
)
5073 /* If we deal with points-to solutions of two restrict qualified
5074 pointers solely rely on the pointed-to variable bitmap intersection.
5075 For two pointers that are based on each other the bitmaps will
5077 if (pt1
->vars_contains_restrict
5078 && pt2
->vars_contains_restrict
)
5080 gcc_assert (pt1
->vars
&& pt2
->vars
);
5081 return bitmap_intersect_p (pt1
->vars
, pt2
->vars
);
5088 /* Dump points-to information to OUTFILE. */
5091 dump_sa_points_to_info (FILE *outfile
)
5095 fprintf (outfile
, "\nPoints-to sets\n\n");
5097 if (dump_flags
& TDF_STATS
)
5099 fprintf (outfile
, "Stats:\n");
5100 fprintf (outfile
, "Total vars: %d\n", stats
.total_vars
);
5101 fprintf (outfile
, "Non-pointer vars: %d\n",
5102 stats
.nonpointer_vars
);
5103 fprintf (outfile
, "Statically unified vars: %d\n",
5104 stats
.unified_vars_static
);
5105 fprintf (outfile
, "Dynamically unified vars: %d\n",
5106 stats
.unified_vars_dynamic
);
5107 fprintf (outfile
, "Iterations: %d\n", stats
.iterations
);
5108 fprintf (outfile
, "Number of edges: %d\n", stats
.num_edges
);
5109 fprintf (outfile
, "Number of implicit edges: %d\n",
5110 stats
.num_implicit_edges
);
5113 for (i
= 0; i
< VEC_length (varinfo_t
, varmap
); i
++)
5114 dump_solution_for_var (outfile
, i
);
5118 /* Debug points-to information to stderr. */
5121 debug_sa_points_to_info (void)
5123 dump_sa_points_to_info (stderr
);
5127 /* Initialize the always-existing constraint variables for NULL
5128 ANYTHING, READONLY, and INTEGER */
5131 init_base_vars (void)
5133 struct constraint_expr lhs
, rhs
;
5134 varinfo_t var_anything
;
5135 varinfo_t var_nothing
;
5136 varinfo_t var_readonly
;
5137 varinfo_t var_escaped
;
5138 varinfo_t var_nonlocal
;
5139 varinfo_t var_callused
;
5140 varinfo_t var_storedanything
;
5141 varinfo_t var_integer
;
5143 /* Create the NULL variable, used to represent that a variable points
5145 var_nothing
= new_var_info (NULL_TREE
, "NULL");
5146 gcc_assert (var_nothing
->id
== nothing_id
);
5147 var_nothing
->is_artificial_var
= 1;
5148 var_nothing
->offset
= 0;
5149 var_nothing
->size
= ~0;
5150 var_nothing
->fullsize
= ~0;
5151 var_nothing
->is_special_var
= 1;
5153 /* Create the ANYTHING variable, used to represent that a variable
5154 points to some unknown piece of memory. */
5155 var_anything
= new_var_info (NULL_TREE
, "ANYTHING");
5156 gcc_assert (var_anything
->id
== anything_id
);
5157 var_anything
->is_artificial_var
= 1;
5158 var_anything
->size
= ~0;
5159 var_anything
->offset
= 0;
5160 var_anything
->next
= NULL
;
5161 var_anything
->fullsize
= ~0;
5162 var_anything
->is_special_var
= 1;
5164 /* Anything points to anything. This makes deref constraints just
5165 work in the presence of linked list and other p = *p type loops,
5166 by saying that *ANYTHING = ANYTHING. */
5168 lhs
.var
= anything_id
;
5170 rhs
.type
= ADDRESSOF
;
5171 rhs
.var
= anything_id
;
5174 /* This specifically does not use process_constraint because
5175 process_constraint ignores all anything = anything constraints, since all
5176 but this one are redundant. */
5177 VEC_safe_push (constraint_t
, heap
, constraints
, new_constraint (lhs
, rhs
));
5179 /* Create the READONLY variable, used to represent that a variable
5180 points to readonly memory. */
5181 var_readonly
= new_var_info (NULL_TREE
, "READONLY");
5182 gcc_assert (var_readonly
->id
== readonly_id
);
5183 var_readonly
->is_artificial_var
= 1;
5184 var_readonly
->offset
= 0;
5185 var_readonly
->size
= ~0;
5186 var_readonly
->fullsize
= ~0;
5187 var_readonly
->next
= NULL
;
5188 var_readonly
->is_special_var
= 1;
5190 /* readonly memory points to anything, in order to make deref
5191 easier. In reality, it points to anything the particular
5192 readonly variable can point to, but we don't track this
5195 lhs
.var
= readonly_id
;
5197 rhs
.type
= ADDRESSOF
;
5198 rhs
.var
= readonly_id
; /* FIXME */
5200 process_constraint (new_constraint (lhs
, rhs
));
5202 /* Create the ESCAPED variable, used to represent the set of escaped
5204 var_escaped
= new_var_info (NULL_TREE
, "ESCAPED");
5205 gcc_assert (var_escaped
->id
== escaped_id
);
5206 var_escaped
->is_artificial_var
= 1;
5207 var_escaped
->offset
= 0;
5208 var_escaped
->size
= ~0;
5209 var_escaped
->fullsize
= ~0;
5210 var_escaped
->is_special_var
= 0;
5212 /* Create the NONLOCAL variable, used to represent the set of nonlocal
5214 var_nonlocal
= new_var_info (NULL_TREE
, "NONLOCAL");
5215 gcc_assert (var_nonlocal
->id
== nonlocal_id
);
5216 var_nonlocal
->is_artificial_var
= 1;
5217 var_nonlocal
->offset
= 0;
5218 var_nonlocal
->size
= ~0;
5219 var_nonlocal
->fullsize
= ~0;
5220 var_nonlocal
->is_special_var
= 1;
5222 /* ESCAPED = *ESCAPED, because escaped is may-deref'd at calls, etc. */
5224 lhs
.var
= escaped_id
;
5227 rhs
.var
= escaped_id
;
5229 process_constraint (new_constraint (lhs
, rhs
));
5231 /* ESCAPED = ESCAPED + UNKNOWN_OFFSET, because if a sub-field escapes the
5232 whole variable escapes. */
5234 lhs
.var
= escaped_id
;
5237 rhs
.var
= escaped_id
;
5238 rhs
.offset
= UNKNOWN_OFFSET
;
5239 process_constraint (new_constraint (lhs
, rhs
));
5241 /* *ESCAPED = NONLOCAL. This is true because we have to assume
5242 everything pointed to by escaped points to what global memory can
5245 lhs
.var
= escaped_id
;
5248 rhs
.var
= nonlocal_id
;
5250 process_constraint (new_constraint (lhs
, rhs
));
5252 /* NONLOCAL = &NONLOCAL, NONLOCAL = &ESCAPED. This is true because
5253 global memory may point to global memory and escaped memory. */
5255 lhs
.var
= nonlocal_id
;
5257 rhs
.type
= ADDRESSOF
;
5258 rhs
.var
= nonlocal_id
;
5260 process_constraint (new_constraint (lhs
, rhs
));
5261 rhs
.type
= ADDRESSOF
;
5262 rhs
.var
= escaped_id
;
5264 process_constraint (new_constraint (lhs
, rhs
));
5266 /* Create the CALLUSED variable, used to represent the set of call-used
5268 var_callused
= new_var_info (NULL_TREE
, "CALLUSED");
5269 gcc_assert (var_callused
->id
== callused_id
);
5270 var_callused
->is_artificial_var
= 1;
5271 var_callused
->offset
= 0;
5272 var_callused
->size
= ~0;
5273 var_callused
->fullsize
= ~0;
5274 var_callused
->is_special_var
= 0;
5276 /* CALLUSED = *CALLUSED, because call-used is may-deref'd at calls, etc. */
5278 lhs
.var
= callused_id
;
5281 rhs
.var
= callused_id
;
5283 process_constraint (new_constraint (lhs
, rhs
));
5285 /* CALLUSED = CALLUSED + UNKNOWN, because if a sub-field is call-used the
5286 whole variable is call-used. */
5288 lhs
.var
= callused_id
;
5291 rhs
.var
= callused_id
;
5292 rhs
.offset
= UNKNOWN_OFFSET
;
5293 process_constraint (new_constraint (lhs
, rhs
));
5295 /* Create the STOREDANYTHING variable, used to represent the set of
5296 variables stored to *ANYTHING. */
5297 var_storedanything
= new_var_info (NULL_TREE
, "STOREDANYTHING");
5298 gcc_assert (var_storedanything
->id
== storedanything_id
);
5299 var_storedanything
->is_artificial_var
= 1;
5300 var_storedanything
->offset
= 0;
5301 var_storedanything
->size
= ~0;
5302 var_storedanything
->fullsize
= ~0;
5303 var_storedanything
->is_special_var
= 0;
5305 /* Create the INTEGER variable, used to represent that a variable points
5306 to what an INTEGER "points to". */
5307 var_integer
= new_var_info (NULL_TREE
, "INTEGER");
5308 gcc_assert (var_integer
->id
== integer_id
);
5309 var_integer
->is_artificial_var
= 1;
5310 var_integer
->size
= ~0;
5311 var_integer
->fullsize
= ~0;
5312 var_integer
->offset
= 0;
5313 var_integer
->next
= NULL
;
5314 var_integer
->is_special_var
= 1;
5316 /* INTEGER = ANYTHING, because we don't know where a dereference of
5317 a random integer will point to. */
5319 lhs
.var
= integer_id
;
5321 rhs
.type
= ADDRESSOF
;
5322 rhs
.var
= anything_id
;
5324 process_constraint (new_constraint (lhs
, rhs
));
5327 /* Initialize things necessary to perform PTA */
5330 init_alias_vars (void)
5332 use_field_sensitive
= (MAX_FIELDS_FOR_FIELD_SENSITIVE
> 1);
5334 bitmap_obstack_initialize (&pta_obstack
);
5335 bitmap_obstack_initialize (&oldpta_obstack
);
5336 bitmap_obstack_initialize (&predbitmap_obstack
);
5338 constraint_pool
= create_alloc_pool ("Constraint pool",
5339 sizeof (struct constraint
), 30);
5340 variable_info_pool
= create_alloc_pool ("Variable info pool",
5341 sizeof (struct variable_info
), 30);
5342 constraints
= VEC_alloc (constraint_t
, heap
, 8);
5343 varmap
= VEC_alloc (varinfo_t
, heap
, 8);
5344 vi_for_tree
= pointer_map_create ();
5346 memset (&stats
, 0, sizeof (stats
));
5347 shared_bitmap_table
= htab_create (511, shared_bitmap_hash
,
5348 shared_bitmap_eq
, free
);
5352 /* Remove the REF and ADDRESS edges from GRAPH, as well as all the
5353 predecessor edges. */
5356 remove_preds_and_fake_succs (constraint_graph_t graph
)
5360 /* Clear the implicit ref and address nodes from the successor
5362 for (i
= 0; i
< FIRST_REF_NODE
; i
++)
5364 if (graph
->succs
[i
])
5365 bitmap_clear_range (graph
->succs
[i
], FIRST_REF_NODE
,
5366 FIRST_REF_NODE
* 2);
5369 /* Free the successor list for the non-ref nodes. */
5370 for (i
= FIRST_REF_NODE
; i
< graph
->size
; i
++)
5372 if (graph
->succs
[i
])
5373 BITMAP_FREE (graph
->succs
[i
]);
5376 /* Now reallocate the size of the successor list as, and blow away
5377 the predecessor bitmaps. */
5378 graph
->size
= VEC_length (varinfo_t
, varmap
);
5379 graph
->succs
= XRESIZEVEC (bitmap
, graph
->succs
, graph
->size
);
5381 free (graph
->implicit_preds
);
5382 graph
->implicit_preds
= NULL
;
5383 free (graph
->preds
);
5384 graph
->preds
= NULL
;
5385 bitmap_obstack_release (&predbitmap_obstack
);
5388 /* Initialize the heapvar for statement mapping. */
5391 init_alias_heapvars (void)
5393 if (!heapvar_for_stmt
)
5394 heapvar_for_stmt
= htab_create_ggc (11, tree_map_hash
, heapvar_map_eq
,
5398 /* Delete the heapvar for statement mapping. */
5401 delete_alias_heapvars (void)
5403 if (heapvar_for_stmt
)
5404 htab_delete (heapvar_for_stmt
);
5405 heapvar_for_stmt
= NULL
;
5408 /* Create points-to sets for the current function. See the comments
5409 at the start of the file for an algorithmic overview. */
5412 compute_points_to_sets (void)
5414 struct scc_info
*si
;
5419 timevar_push (TV_TREE_PTA
);
5422 init_alias_heapvars ();
5424 intra_create_variable_infos ();
5426 /* Now walk all statements and derive aliases. */
5429 gimple_stmt_iterator gsi
;
5431 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5433 gimple phi
= gsi_stmt (gsi
);
5435 if (is_gimple_reg (gimple_phi_result (phi
)))
5436 find_func_aliases (phi
);
5439 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5441 gimple stmt
= gsi_stmt (gsi
);
5443 find_func_aliases (stmt
);
5449 fprintf (dump_file
, "Points-to analysis\n\nConstraints:\n\n");
5450 dump_constraints (dump_file
);
5455 "\nCollapsing static cycles and doing variable "
5458 init_graph (VEC_length (varinfo_t
, varmap
) * 2);
5461 fprintf (dump_file
, "Building predecessor graph\n");
5462 build_pred_graph ();
5465 fprintf (dump_file
, "Detecting pointer and location "
5467 si
= perform_var_substitution (graph
);
5470 fprintf (dump_file
, "Rewriting constraints and unifying "
5472 rewrite_constraints (graph
, si
);
5474 build_succ_graph ();
5475 free_var_substitution_info (si
);
5477 if (dump_file
&& (dump_flags
& TDF_GRAPH
))
5478 dump_constraint_graph (dump_file
);
5480 move_complex_constraints (graph
);
5483 fprintf (dump_file
, "Uniting pointer but not location equivalent "
5485 unite_pointer_equivalences (graph
);
5488 fprintf (dump_file
, "Finding indirect cycles\n");
5489 find_indirect_cycles (graph
);
5491 /* Implicit nodes and predecessors are no longer necessary at this
5493 remove_preds_and_fake_succs (graph
);
5496 fprintf (dump_file
, "Solving graph\n");
5498 solve_graph (graph
);
5501 dump_sa_points_to_info (dump_file
);
5503 /* Compute the points-to sets for ESCAPED and CALLUSED used for
5504 call-clobber analysis. */
5505 find_what_var_points_to (get_varinfo (escaped_id
),
5506 &cfun
->gimple_df
->escaped
);
5507 find_what_var_points_to (get_varinfo (callused_id
),
5508 &cfun
->gimple_df
->callused
);
5510 /* Make sure the ESCAPED solution (which is used as placeholder in
5511 other solutions) does not reference itself. This simplifies
5512 points-to solution queries. */
5513 cfun
->gimple_df
->escaped
.escaped
= 0;
5515 /* Mark escaped HEAP variables as global. */
5516 for (i
= 0; VEC_iterate (varinfo_t
, varmap
, i
, vi
); ++i
)
5518 && !vi
->is_restrict_var
5519 && !vi
->is_global_var
)
5520 DECL_EXTERNAL (vi
->decl
) = vi
->is_global_var
5521 = pt_solution_includes (&cfun
->gimple_df
->escaped
, vi
->decl
);
5523 /* Compute the points-to sets for pointer SSA_NAMEs. */
5524 for (i
= 0; i
< num_ssa_names
; ++i
)
5526 tree ptr
= ssa_name (i
);
5528 && POINTER_TYPE_P (TREE_TYPE (ptr
)))
5529 find_what_p_points_to (ptr
);
5532 timevar_pop (TV_TREE_PTA
);
5534 have_alias_info
= true;
5538 /* Delete created points-to sets. */
5541 delete_points_to_sets (void)
5545 htab_delete (shared_bitmap_table
);
5546 if (dump_file
&& (dump_flags
& TDF_STATS
))
5547 fprintf (dump_file
, "Points to sets created:%d\n",
5548 stats
.points_to_sets_created
);
5550 pointer_map_destroy (vi_for_tree
);
5551 bitmap_obstack_release (&pta_obstack
);
5552 VEC_free (constraint_t
, heap
, constraints
);
5554 for (i
= 0; i
< graph
->size
; i
++)
5555 VEC_free (constraint_t
, heap
, graph
->complex[i
]);
5556 free (graph
->complex);
5559 free (graph
->succs
);
5561 free (graph
->pe_rep
);
5562 free (graph
->indirect_cycles
);
5565 VEC_free (varinfo_t
, heap
, varmap
);
5566 free_alloc_pool (variable_info_pool
);
5567 free_alloc_pool (constraint_pool
);
5568 have_alias_info
= false;
5572 /* Compute points-to information for every SSA_NAME pointer in the
5573 current function and compute the transitive closure of escaped
5574 variables to re-initialize the call-clobber states of local variables. */
5577 compute_may_aliases (void)
5579 /* For each pointer P_i, determine the sets of variables that P_i may
5580 point-to. Compute the reachability set of escaped and call-used
5582 compute_points_to_sets ();
5584 /* Debugging dumps. */
5587 dump_alias_info (dump_file
);
5589 if (dump_flags
& TDF_DETAILS
)
5590 dump_referenced_vars (dump_file
);
5593 /* Deallocate memory used by aliasing data structures and the internal
5594 points-to solution. */
5595 delete_points_to_sets ();
5597 gcc_assert (!need_ssa_update_p (cfun
));
5603 gate_tree_pta (void)
5605 return flag_tree_pta
;
5608 /* A dummy pass to cause points-to information to be computed via
5609 TODO_rebuild_alias. */
5611 struct gimple_opt_pass pass_build_alias
=
5616 gate_tree_pta
, /* gate */
5620 0, /* static_pass_number */
5621 TV_NONE
, /* tv_id */
5622 PROP_cfg
| PROP_ssa
, /* properties_required */
5623 0, /* properties_provided */
5624 0, /* properties_destroyed */
5625 0, /* todo_flags_start */
5626 TODO_rebuild_alias
| TODO_dump_func
/* todo_flags_finish */
5630 /* A dummy pass to cause points-to information to be computed via
5631 TODO_rebuild_alias. */
5633 struct gimple_opt_pass pass_build_ealias
=
5637 "ealias", /* name */
5638 gate_tree_pta
, /* gate */
5642 0, /* static_pass_number */
5643 TV_NONE
, /* tv_id */
5644 PROP_cfg
| PROP_ssa
, /* properties_required */
5645 0, /* properties_provided */
5646 0, /* properties_destroyed */
5647 0, /* todo_flags_start */
5648 TODO_rebuild_alias
| TODO_dump_func
/* todo_flags_finish */
5653 /* Return true if we should execute IPA PTA. */
5657 return (flag_ipa_pta
5658 /* Don't bother doing anything if the program has errors. */
5659 && !(errorcount
|| sorrycount
));
5662 /* Execute the driver for IPA PTA. */
5664 ipa_pta_execute (void)
5666 struct cgraph_node
*node
;
5667 struct scc_info
*si
;
5670 init_alias_heapvars ();
5673 for (node
= cgraph_nodes
; node
; node
= node
->next
)
5677 varid
= create_function_info_for (node
->decl
,
5678 cgraph_node_name (node
));
5679 if (node
->local
.externally_visible
)
5681 varinfo_t fi
= get_varinfo (varid
);
5682 for (; fi
; fi
= fi
->next
)
5683 make_constraint_from (fi
, anything_id
);
5686 for (node
= cgraph_nodes
; node
; node
= node
->next
)
5690 struct function
*func
= DECL_STRUCT_FUNCTION (node
->decl
);
5692 tree old_func_decl
= current_function_decl
;
5695 "Generating constraints for %s\n",
5696 cgraph_node_name (node
));
5698 current_function_decl
= node
->decl
;
5700 FOR_EACH_BB_FN (bb
, func
)
5702 gimple_stmt_iterator gsi
;
5704 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
);
5707 gimple phi
= gsi_stmt (gsi
);
5709 if (is_gimple_reg (gimple_phi_result (phi
)))
5710 find_func_aliases (phi
);
5713 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
5714 find_func_aliases (gsi_stmt (gsi
));
5716 current_function_decl
= old_func_decl
;
5721 /* Make point to anything. */
5727 fprintf (dump_file
, "Points-to analysis\n\nConstraints:\n\n");
5728 dump_constraints (dump_file
);
5733 "\nCollapsing static cycles and doing variable "
5736 init_graph (VEC_length (varinfo_t
, varmap
) * 2);
5737 build_pred_graph ();
5738 si
= perform_var_substitution (graph
);
5739 rewrite_constraints (graph
, si
);
5741 build_succ_graph ();
5742 free_var_substitution_info (si
);
5743 move_complex_constraints (graph
);
5744 unite_pointer_equivalences (graph
);
5745 find_indirect_cycles (graph
);
5747 /* Implicit nodes and predecessors are no longer necessary at this
5749 remove_preds_and_fake_succs (graph
);
5752 fprintf (dump_file
, "\nSolving graph\n");
5754 solve_graph (graph
);
5757 dump_sa_points_to_info (dump_file
);
5760 delete_alias_heapvars ();
5761 delete_points_to_sets ();
5765 struct simple_ipa_opt_pass pass_ipa_pta
=
5770 gate_ipa_pta
, /* gate */
5771 ipa_pta_execute
, /* execute */
5774 0, /* static_pass_number */
5775 TV_IPA_PTA
, /* tv_id */
5776 0, /* properties_required */
5777 0, /* properties_provided */
5778 0, /* properties_destroyed */
5779 0, /* todo_flags_start */
5780 TODO_update_ssa
/* todo_flags_finish */
5785 #include "gt-tree-ssa-structalias.h"