1/* Tree based alias analysis and alias oracle.
2   Copyright (C) 2008-2015 Free Software Foundation, Inc.
3   Contributed by Richard Guenther  <rguenther@suse.de>
4
5   This file is part of GCC.
6
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.
11
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.
16
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/>.  */
20
21#ifndef TREE_SSA_ALIAS_H
22#define TREE_SSA_ALIAS_H
23
24/* The points-to solution.
25
26   The points-to solution is a union of pt_vars and the abstract
27   sets specified by the flags.  */
28struct GTY(()) pt_solution
29{
30  /* Nonzero if points-to analysis couldn't determine where this pointer
31     is pointing to.  */
32  unsigned int anything : 1;
33
34  /* Nonzero if the points-to set includes any global memory.  Note that
35     even if this is zero pt_vars can still include global variables.  */
36  unsigned int nonlocal : 1;
37
38  /* Nonzero if the points-to set includes the local escaped solution by
39     reference.  */
40  unsigned int escaped : 1;
41
42  /* Nonzero if the points-to set includes the IPA escaped solution by
43     reference.  */
44  unsigned int ipa_escaped : 1;
45
46  /* Nonzero if the points-to set includes 'nothing', the points-to set
47     includes memory at address NULL.  */
48  unsigned int null : 1;
49
50
51  /* Nonzero if the vars bitmap includes a variable included in 'nonlocal'.  */
52  unsigned int vars_contains_nonlocal : 1;
53  /* Nonzero if the vars bitmap includes a variable included in 'escaped'.  */
54  unsigned int vars_contains_escaped : 1;
55  /* Nonzero if the vars bitmap includes a anonymous heap variable that
56     escaped the function and thus became global.  */
57  unsigned int vars_contains_escaped_heap : 1;
58
59  /* Set of variables that this pointer may point to.  */
60  bitmap vars;
61};
62
63
64/* Simplified and cached information about a memory reference tree.
65   Used by the alias-oracle internally and externally in alternate
66   interfaces.  */
67struct ao_ref
68{
69  /* The original full memory reference tree or NULL_TREE if that is
70     not available.  */
71  tree ref;
72
73  /* The following fields are the decomposed reference as returned
74     by get_ref_base_and_extent.  */
75  /* The base object of the memory reference or NULL_TREE if all of
76     the following fields are not yet computed.  */
77  tree base;
78  /* The offset relative to the base.  */
79  HOST_WIDE_INT offset;
80  /* The size of the access.  */
81  HOST_WIDE_INT size;
82  /* The maximum possible extent of the access or -1 if unconstrained.  */
83  HOST_WIDE_INT max_size;
84
85  /* The alias set of the access or -1 if not yet computed.  */
86  alias_set_type ref_alias_set;
87
88  /* The alias set of the base object or -1 if not yet computed.  */
89  alias_set_type base_alias_set;
90
91  /* Whether the memory is considered a volatile access.  */
92  bool volatile_p;
93};
94
95
96/* In tree-ssa-alias.c  */
97extern void ao_ref_init (ao_ref *, tree);
98extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
99extern tree ao_ref_base (ao_ref *);
100extern alias_set_type ao_ref_alias_set (ao_ref *);
101extern alias_set_type ao_ref_base_alias_set (ao_ref *);
102extern bool ptr_deref_may_alias_global_p (tree);
103extern bool ptr_derefs_may_alias_p (tree, tree);
104extern bool ref_may_alias_global_p (tree);
105extern bool ref_may_alias_global_p (ao_ref *);
106extern bool refs_may_alias_p (tree, tree);
107extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
108extern bool refs_anti_dependent_p (tree, tree);
109extern bool refs_output_dependent_p (tree, tree);
110extern bool ref_maybe_used_by_stmt_p (gimple, tree);
111extern bool ref_maybe_used_by_stmt_p (gimple, ao_ref *);
112extern bool stmt_may_clobber_global_p (gimple);
113extern bool stmt_may_clobber_ref_p (gimple, tree);
114extern bool stmt_may_clobber_ref_p_1 (gimple, ao_ref *);
115extern bool call_may_clobber_ref_p (gcall *, tree);
116extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *);
117extern bool stmt_kills_ref_p (gimple, tree);
118extern bool stmt_kills_ref_p (gimple, ao_ref *);
119extern tree get_continuation_for_phi (gimple, ao_ref *,
120				      unsigned int *, bitmap *, bool,
121				      void *(*)(ao_ref *, tree, void *, bool),
122				      void *);
123extern void *walk_non_aliased_vuses (ao_ref *, tree,
124				     void *(*)(ao_ref *, tree,
125					       unsigned int, void *),
126				     void *(*)(ao_ref *, tree, void *, bool),
127				     tree (*)(tree),
128				     void *);
129extern unsigned int walk_aliased_vdefs (ao_ref *, tree,
130					bool (*)(ao_ref *, tree, void *),
131					void *, bitmap *,
132					bool *function_entry_reached = NULL);
133extern void dump_alias_info (FILE *);
134extern void debug_alias_info (void);
135extern void dump_points_to_solution (FILE *, struct pt_solution *);
136extern void debug (pt_solution &ref);
137extern void debug (pt_solution *ptr);
138extern void dump_points_to_info_for (FILE *, tree);
139extern void debug_points_to_info_for (tree);
140extern void dump_alias_stats (FILE *);
141
142
143/* In tree-ssa-structalias.c  */
144extern unsigned int compute_may_aliases (void);
145extern bool pt_solution_empty_p (struct pt_solution *);
146extern bool pt_solution_singleton_p (struct pt_solution *, unsigned *);
147extern bool pt_solution_includes_global (struct pt_solution *);
148extern bool pt_solution_includes (struct pt_solution *, const_tree);
149extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
150extern void pt_solution_reset (struct pt_solution *);
151extern void pt_solution_set (struct pt_solution *, bitmap, bool);
152extern void pt_solution_set_var (struct pt_solution *, tree);
153
154extern void dump_pta_stats (FILE *);
155
156extern GTY(()) struct pt_solution ipa_escaped_pt;
157
158/* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
159   overlap.  SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
160   range is open-ended.  Otherwise return false.  */
161
162static inline bool
163ranges_overlap_p (HOST_WIDE_INT pos1,
164		  unsigned HOST_WIDE_INT size1,
165		  HOST_WIDE_INT pos2,
166		  unsigned HOST_WIDE_INT size2)
167{
168  if (pos1 >= pos2
169      && (size2 == (unsigned HOST_WIDE_INT)-1
170	  || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
171    return true;
172  if (pos2 >= pos1
173      && (size1 == (unsigned HOST_WIDE_INT)-1
174	  || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
175    return true;
176
177  return false;
178}
179
180
181
182#endif /* TREE_SSA_ALIAS_H  */
183