Line data Source code
1 : /* Tree based alias analysis and alias oracle.
2 : Copyright (C) 2008-2026 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 points-to set includes a readonly object like a
51 : STRING_CST that does not have an underlying declaration but will
52 : end up in the constant pool. */
53 : unsigned int const_pool : 1;
54 :
55 : /* Nonzero if the vars bitmap includes a variable included in 'nonlocal'. */
56 : unsigned int vars_contains_nonlocal : 1;
57 : /* Nonzero if the vars bitmap includes a local automatic variable. */
58 : unsigned int vars_contains_auto : 1;
59 : /* Nonzero if the vars bitmap includes a variable included in 'escaped'. */
60 : unsigned int vars_contains_escaped : 1;
61 : /* Nonzero if the vars bitmap includes a anonymous heap variable that
62 : escaped the function and thus became global. */
63 : unsigned int vars_contains_escaped_heap : 1;
64 : /* Nonzero if the vars bitmap includes a anonymous variable used to
65 : represent storage pointed to by a restrict qualified pointer. */
66 : unsigned int vars_contains_restrict : 1;
67 : /* Nonzero if the vars bitmap includes an interposable variable. */
68 : unsigned int vars_contains_interposable : 1;
69 :
70 : /* Set of variables that this pointer may point to. */
71 : bitmap vars;
72 : };
73 :
74 :
75 : /* Simplified and cached information about a memory reference tree.
76 : Used by the alias-oracle internally and externally in alternate
77 : interfaces. */
78 : class ao_ref
79 : {
80 : public:
81 : /* The original full memory reference tree or NULL_TREE if that is
82 : not available. */
83 : tree ref;
84 :
85 : /* The following fields are the decomposed reference as returned
86 : by get_ref_base_and_extent. */
87 : /* The base object of the memory reference or NULL_TREE if all of
88 : the following fields are not yet computed. */
89 : tree base;
90 : /* The offset relative to the base. */
91 : poly_int64 offset;
92 : /* The size of the access. */
93 : poly_int64 size;
94 : /* The maximum possible extent of the access or -1 if unconstrained. */
95 : poly_int64 max_size;
96 :
97 : /* The alias set of the access or -1 if not yet computed. */
98 : alias_set_type ref_alias_set;
99 :
100 : /* The alias set of the base object or -1 if not yet computed. */
101 : alias_set_type base_alias_set;
102 :
103 : /* Whether the memory is considered a volatile access. */
104 : bool volatile_p;
105 :
106 : bool max_size_known_p () const;
107 : };
108 :
109 : /* Return true if the maximum size is known, rather than the special -1
110 : marker. */
111 :
112 : inline bool
113 1067109039 : ao_ref::max_size_known_p () const
114 : {
115 1070015401 : return known_size_p (max_size);
116 : }
117 :
118 : /* In tree-ssa-alias.cc */
119 : extern void ao_ref_init (ao_ref *, tree);
120 : extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
121 : extern void ao_ref_init_from_ptr_and_range (ao_ref *, tree, bool,
122 : poly_int64, poly_int64,
123 : poly_int64);
124 : extern tree ao_ref_base (ao_ref *);
125 : extern alias_set_type ao_ref_alias_set (ao_ref *);
126 : extern alias_set_type ao_ref_base_alias_set (ao_ref *);
127 : extern tree ao_ref_alias_ptr_type (ao_ref *);
128 : extern tree ao_ref_base_alias_ptr_type (ao_ref *);
129 : extern bool ao_ref_alignment (ao_ref *, unsigned int *,
130 : unsigned HOST_WIDE_INT *);
131 : extern bool ptr_deref_may_alias_global_p (tree, bool);
132 : extern bool ptr_deref_may_alias_auto_p (tree);
133 : extern bool ptr_derefs_may_alias_p (tree, tree);
134 : extern bool ptrs_compare_unequal (tree, tree);
135 : extern bool ref_may_alias_global_p (tree, bool);
136 : extern bool ref_may_alias_global_p (ao_ref *, bool);
137 : extern bool refs_may_alias_p (tree, tree, bool = true);
138 : extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
139 : extern bool refs_anti_dependent_p (tree, tree);
140 : extern bool refs_output_dependent_p (tree, tree);
141 : extern bool ref_maybe_used_by_stmt_p (gimple *, tree, bool = true);
142 : extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *, bool = true);
143 : extern bool stmt_may_clobber_global_p (gimple *, bool);
144 : extern bool stmt_may_clobber_ref_p (gimple *, tree, bool = true);
145 : extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *, bool = true);
146 : extern bool call_may_clobber_ref_p (gcall *, tree, bool = true);
147 : extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *, bool = true);
148 : extern bool stmt_kills_ref_p (gimple *, tree);
149 : extern bool stmt_kills_ref_p (gimple *, ao_ref *);
150 : extern bool ref_can_have_store_data_races (tree);
151 :
152 : enum translate_flags
153 : { TR_TRANSLATE, TR_VALUEIZE_AND_DISAMBIGUATE, TR_DISAMBIGUATE };
154 : extern tree get_continuation_for_phi (gphi *, ao_ref *, bool,
155 : unsigned int &, bitmap *, bool,
156 : void *(*)(ao_ref *, tree, void *,
157 : translate_flags *),
158 : void *,
159 : bool (*)(edge, void *) = nullptr,
160 : translate_flags
161 : = TR_VALUEIZE_AND_DISAMBIGUATE);
162 : extern void *walk_non_aliased_vuses (ao_ref *, tree, bool,
163 : void *(*)(ao_ref *, tree, void *),
164 : void *(*)(ao_ref *, tree, void *,
165 : translate_flags *),
166 : bool (*)(edge, void *),
167 : tree (*)(tree), unsigned &, void *);
168 : extern int walk_aliased_vdefs (ao_ref *, tree,
169 : bool (*)(ao_ref *, tree, void *),
170 : void *, bitmap *,
171 : bool *function_entry_reached = NULL,
172 : unsigned int limit = 0);
173 : extern void dump_alias_info (FILE *);
174 : extern void debug_alias_info (void);
175 : extern void dump_points_to_solution (FILE *, struct pt_solution *);
176 : extern void debug (pt_solution &ref);
177 : extern void debug (pt_solution *ptr);
178 : extern void dump_points_to_info_for (FILE *, tree);
179 : extern void debug_points_to_info_for (tree);
180 : extern void dump_alias_stats (FILE *);
181 :
182 :
183 : /* In tree-ssa-structalias.cc */
184 : extern unsigned int compute_may_aliases (void);
185 : extern bool pt_solution_empty_p (const pt_solution *);
186 : extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
187 : extern bool pt_solution_includes_global (struct pt_solution *, bool);
188 : extern bool pt_solution_includes_auto (struct pt_solution *);
189 : extern bool pt_solution_includes (struct pt_solution *, const_tree);
190 : extern bool pt_solution_includes_const_pool (struct pt_solution *);
191 : extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
192 : extern void pt_solution_reset (struct pt_solution *);
193 : extern void pt_solution_set (struct pt_solution *, bitmap, bool);
194 : extern void pt_solution_set_var (struct pt_solution *, tree);
195 :
196 : extern void dump_pta_stats (FILE *);
197 :
198 : extern GTY(()) struct pt_solution ipa_escaped_pt;
199 :
200 : /* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
201 : overlap. SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
202 : range is open-ended. Otherwise return false. */
203 :
204 : inline bool
205 3155983 : ranges_overlap_p (HOST_WIDE_INT pos1,
206 : unsigned HOST_WIDE_INT size1,
207 : HOST_WIDE_INT pos2,
208 : unsigned HOST_WIDE_INT size2)
209 : {
210 3155983 : if (size1 == 0 || size2 == 0)
211 : return false;
212 3155967 : if (pos1 >= pos2
213 3153937 : && (size2 == (unsigned HOST_WIDE_INT)-1
214 3153937 : || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
215 : return true;
216 1166094 : if (pos2 >= pos1
217 2030 : && (size1 == (unsigned HOST_WIDE_INT)-1
218 2030 : || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
219 1985 : return true;
220 :
221 : return false;
222 : }
223 :
224 :
225 :
226 : #endif /* TREE_SSA_ALIAS_H */
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