1 /* Tree based alias analysis and alias oracle.
2 Copyright (C) 2008-2023 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. */
28 struct 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 /* Nonzero if the vars bitmap includes a variable included in 'nonlocal'. */
51 unsigned int vars_contains_nonlocal : 1;
52 /* Nonzero if the vars bitmap includes a variable included in 'escaped'. */
53 unsigned int vars_contains_escaped : 1;
54 /* Nonzero if the vars bitmap includes a anonymous heap variable that
55 escaped the function and thus became global. */
56 unsigned int vars_contains_escaped_heap : 1;
57 /* Nonzero if the vars bitmap includes a anonymous variable used to
58 represent storage pointed to by a restrict qualified pointer. */
59 unsigned int vars_contains_restrict : 1;
60 /* Nonzero if the vars bitmap includes an interposable variable. */
61 unsigned int vars_contains_interposable : 1;
62
63 /* Set of variables that this pointer may point to. */
64 bitmap vars;
65 };
66
67
68 /* Simplified and cached information about a memory reference tree.
69 Used by the alias-oracle internally and externally in alternate
70 interfaces. */
71 class ao_ref
72 {
73 public:
74 /* The original full memory reference tree or NULL_TREE if that is
75 not available. */
76 tree ref;
77
78 /* The following fields are the decomposed reference as returned
79 by get_ref_base_and_extent. */
80 /* The base object of the memory reference or NULL_TREE if all of
81 the following fields are not yet computed. */
82 tree base;
83 /* The offset relative to the base. */
84 poly_int64 offset;
85 /* The size of the access. */
86 poly_int64 size;
87 /* The maximum possible extent of the access or -1 if unconstrained. */
88 poly_int64 max_size;
89
90 /* The alias set of the access or -1 if not yet computed. */
91 alias_set_type ref_alias_set;
92
93 /* The alias set of the base object or -1 if not yet computed. */
94 alias_set_type base_alias_set;
95
96 /* Whether the memory is considered a volatile access. */
97 bool volatile_p;
98
99 bool max_size_known_p () const;
100 };
101
102 /* Return true if the maximum size is known, rather than the special -1
103 marker. */
104
105 inline bool
106 ao_ref::max_size_known_p () const
107 {
108 return known_size_p (max_size);
109 }
110
111 /* In tree-ssa-alias.cc */
112 extern void ao_ref_init (ao_ref *, tree);
113 extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
114 extern void ao_ref_init_from_ptr_and_range (ao_ref *, tree, bool,
115 poly_int64, poly_int64,
116 poly_int64);
117 extern tree ao_ref_base (ao_ref *);
118 extern alias_set_type ao_ref_alias_set (ao_ref *);
119 extern alias_set_type ao_ref_base_alias_set (ao_ref *);
120 extern tree ao_ref_alias_ptr_type (ao_ref *);
121 extern tree ao_ref_base_alias_ptr_type (ao_ref *);
122 extern bool ao_ref_alignment (ao_ref *, unsigned int *,
123 unsigned HOST_WIDE_INT *);
124 extern bool ptr_deref_may_alias_global_p (tree, bool);
125 extern bool ptr_derefs_may_alias_p (tree, tree);
126 extern bool ptrs_compare_unequal (tree, tree);
127 extern bool ref_may_alias_global_p (tree, bool);
128 extern bool ref_may_alias_global_p (ao_ref *, bool);
129 extern bool refs_may_alias_p (tree, tree, bool = true);
130 extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
131 extern bool refs_anti_dependent_p (tree, tree);
132 extern bool refs_output_dependent_p (tree, tree);
133 extern bool ref_maybe_used_by_stmt_p (gimple *, tree, bool = true);
134 extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *, bool = true);
135 extern bool stmt_may_clobber_global_p (gimple *, bool);
136 extern bool stmt_may_clobber_ref_p (gimple *, tree, bool = true);
137 extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *, bool = true);
138 extern bool call_may_clobber_ref_p (gcall *, tree, bool = true);
139 extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *, bool = true);
140 extern bool stmt_kills_ref_p (gimple *, tree);
141 extern bool stmt_kills_ref_p (gimple *, ao_ref *);
142 enum translate_flags
143 { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
144 extern tree get_continuation_for_phi (gimple *, ao_ref *, bool,
145 unsigned int &, bitmap *, bool,
146 void *(*)(ao_ref *, tree, void *,
147 translate_flags *),
148 void *, translate_flags
149 = TR_VALUEIZE_AND_DISAMBIGUATE);
150 extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
151 void *(*)(ao_ref *, tree, void *),
152 void *(*)(ao_ref *, tree, void *,
153 translate_flags *),
154 tree (*)(tree), unsigned &, void *);
155 extern int walk_aliased_vdefs (ao_ref *, tree,
156 bool (*)(ao_ref *, tree, void *),
157 void *, bitmap *,
158 bool *function_entry_reached = NULL,
159 unsigned int limit = 0);
160 extern void dump_alias_info (FILE *);
161 extern void debug_alias_info (void);
162 extern void dump_points_to_solution (FILE *, struct pt_solution *);
163 extern void debug (pt_solution &ref);
164 extern void debug (pt_solution *ptr);
165 extern void dump_points_to_info_for (FILE *, tree);
166 extern void debug_points_to_info_for (tree);
167 extern void dump_alias_stats (FILE *);
168
169
170 /* In tree-ssa-structalias.cc */
171 extern unsigned int compute_may_aliases (void);
172 extern bool pt_solution_empty_p (const pt_solution *);
173 extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
174 extern bool pt_solution_includes_global (struct pt_solution *, bool);
175 extern bool pt_solution_includes (struct pt_solution *, const_tree);
176 extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
177 extern void pt_solution_reset (struct pt_solution *);
178 extern void pt_solution_set (struct pt_solution *, bitmap, bool);
179 extern void pt_solution_set_var (struct pt_solution *, tree);
180
181 extern void dump_pta_stats (FILE *);
182
183 extern GTY(()) struct pt_solution ipa_escaped_pt;
184
185 /* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
186 overlap. SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
187 range is open-ended. Otherwise return false. */
188
189 inline bool
190 ranges_overlap_p (HOST_WIDE_INT pos1,
191 unsigned HOST_WIDE_INT size1,
192 HOST_WIDE_INT pos2,
193 unsigned HOST_WIDE_INT size2)
194 {
195 if (size1 == 0 || size2 == 0)
196 return false;
197 if (pos1 >= pos2
198 && (size2 == (unsigned HOST_WIDE_INT)-1
199 || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
200 return true;
201 if (pos2 >= pos1
202 && (size1 == (unsigned HOST_WIDE_INT)-1
203 || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
204 return true;
205
206 return false;
207 }
208
209
210
211 #endif /* TREE_SSA_ALIAS_H */