tree-ssa-alias.h revision 1.8 
1/* Tree based alias analysis and alias oracle.
2   Copyright (C) 2008-2017 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  /* 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.  */
71struct ao_ref
72{
73  /* The original full memory reference tree or NULL_TREE if that is
74     not available.  */
75  tree ref;
76
77  /* The following fields are the decomposed reference as returned
78     by get_ref_base_and_extent.  */
79  /* The base object of the memory reference or NULL_TREE if all of
80     the following fields are not yet computed.  */
81  tree base;
82  /* The offset relative to the base.  */
83  HOST_WIDE_INT offset;
84  /* The size of the access.  */
85  HOST_WIDE_INT size;
86  /* The maximum possible extent of the access or -1 if unconstrained.  */
87  HOST_WIDE_INT max_size;
88
89  /* The alias set of the access or -1 if not yet computed.  */
90  alias_set_type ref_alias_set;
91
92  /* The alias set of the base object or -1 if not yet computed.  */
93  alias_set_type base_alias_set;
94
95  /* Whether the memory is considered a volatile access.  */
96  bool volatile_p;
97};
98
99
100/* In tree-ssa-alias.c  */
101extern void ao_ref_init (ao_ref *, tree);
102extern void ao_ref_init_from_ptr_and_size (ao_ref *, tree, tree);
103extern tree ao_ref_base (ao_ref *);
104extern alias_set_type ao_ref_alias_set (ao_ref *);
105extern alias_set_type ao_ref_base_alias_set (ao_ref *);
106extern bool ptr_deref_may_alias_global_p (tree);
107extern bool ptr_derefs_may_alias_p (tree, tree);
108extern bool ptrs_compare_unequal (tree, tree);
109extern bool ref_may_alias_global_p (tree);
110extern bool ref_may_alias_global_p (ao_ref *);
111extern bool refs_may_alias_p (tree, tree);
112extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
113extern bool refs_anti_dependent_p (tree, tree);
114extern bool refs_output_dependent_p (tree, tree);
115extern bool ref_maybe_used_by_stmt_p (gimple *, tree);
116extern bool ref_maybe_used_by_stmt_p (gimple *, ao_ref *);
117extern bool stmt_may_clobber_global_p (gimple *);
118extern bool stmt_may_clobber_ref_p (gimple *, tree);
119extern bool stmt_may_clobber_ref_p_1 (gimple *, ao_ref *);
120extern bool call_may_clobber_ref_p (gcall *, tree);
121extern bool call_may_clobber_ref_p_1 (gcall *, ao_ref *);
122extern bool stmt_kills_ref_p (gimple *, tree);
123extern bool stmt_kills_ref_p (gimple *, ao_ref *);
124extern tree get_continuation_for_phi (gimple *, ao_ref *,
125				      unsigned int *, bitmap *, bool,
126				      void *(*)(ao_ref *, tree, void *, bool *),
127				      void *);
128extern void *walk_non_aliased_vuses (ao_ref *, tree,
129				     void *(*)(ao_ref *, tree,
130					       unsigned int, void *),
131				     void *(*)(ao_ref *, tree, void *, bool *),
132				     tree (*)(tree),
133				     void *);
134extern int walk_aliased_vdefs (ao_ref *, tree,
135			       bool (*)(ao_ref *, tree, void *),
136			       void *, bitmap *,
137			       bool *function_entry_reached = NULL,
138			       unsigned int limit = 0);
139extern void dump_alias_info (FILE *);
140extern void debug_alias_info (void);
141extern void dump_points_to_solution (FILE *, struct pt_solution *);
142extern void debug (pt_solution &ref);
143extern void debug (pt_solution *ptr);
144extern void dump_points_to_info_for (FILE *, tree);
145extern void debug_points_to_info_for (tree);
146extern void dump_alias_stats (FILE *);
147
148
149/* In tree-ssa-structalias.c  */
150extern unsigned int compute_may_aliases (void);
151extern bool pt_solution_empty_p (struct pt_solution *);
152extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
153extern bool pt_solution_includes_global (struct pt_solution *);
154extern bool pt_solution_includes (struct pt_solution *, const_tree);
155extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
156extern void pt_solution_reset (struct pt_solution *);
157extern void pt_solution_set (struct pt_solution *, bitmap, bool);
158extern void pt_solution_set_var (struct pt_solution *, tree);
159
160extern void dump_pta_stats (FILE *);
161
162extern GTY(()) struct pt_solution ipa_escaped_pt;
163
164/* Return true, if the two ranges [POS1, SIZE1] and [POS2, SIZE2]
165   overlap.  SIZE1 and/or SIZE2 can be (unsigned)-1 in which case the
166   range is open-ended.  Otherwise return false.  */
167
168static inline bool
169ranges_overlap_p (HOST_WIDE_INT pos1,
170		  unsigned HOST_WIDE_INT size1,
171		  HOST_WIDE_INT pos2,
172		  unsigned HOST_WIDE_INT size2)
173{
174  if (pos1 >= pos2
175      && (size2 == (unsigned HOST_WIDE_INT)-1
176	  || pos1 < (pos2 + (HOST_WIDE_INT) size2)))
177    return true;
178  if (pos2 >= pos1
179      && (size1 == (unsigned HOST_WIDE_INT)-1
180	  || pos2 < (pos1 + (HOST_WIDE_INT) size1)))
181    return true;
182
183  return false;
184}
185
186
187
188#endif /* TREE_SSA_ALIAS_H  */
189