1 /* Support routines for value queries.
2 Copyright (C) 2020-2021 Free Software Foundation, Inc.
3 Contributed by Aldy Hernandez <aldyh@redhat.com> and
4 Andrew Macleod <amacleod@redhat.com>.
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
12
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
21
22 #ifndef GCC_QUERY_H
23 #define GCC_QUERY_H
24
25 #include "value-relation.h"
26
27 // The value_query class is used by optimization passes that require
28 // valueizing SSA names in terms of a tree value, but have no neeed
29 // for ranges.
30 //
31 // value_of_expr must be provided. The default for value_on_edge and
32 // value_of_stmt is to call value_of_expr.
33 //
34 // This implies the valuation is global in nature. If a pass can make
35 // use of more specific information, it can override the other queries.
36 //
37 // Proper usage of the correct query in passes will enable other
38 // valuation mechanisms to produce more precise results.
39
40 class value_query
41 {
42 public:
value_query()43 value_query () { }
44 // Return the singleton expression for EXPR at a gimple statement,
45 // or NULL if none found.
46 virtual tree value_of_expr (tree expr, gimple * = NULL) = 0;
47 // Return the singleton expression for EXPR at an edge, or NULL if
48 // none found.
49 virtual tree value_on_edge (edge, tree expr);
50 // Return the singleton expression for the LHS of a gimple
51 // statement, assuming an (optional) initial value of NAME. Returns
52 // NULL if none found.
53 //
54 // Note that this method calculates the range the LHS would have
55 // *after* the statement has executed.
56 virtual tree value_of_stmt (gimple *, tree name = NULL);
57
58 private:
59 DISABLE_COPY_AND_ASSIGN (value_query);
60 };
61
62 // The range_query class is used by optimization passes which are
63 // range aware.
64 //
65 // range_of_expr must be provided. The default for range_on_edge and
66 // range_of_stmt is to call range_of_expr. If a pass can make use of
67 // more specific information, then it can override the other queries.
68 //
69 // The default for the value_* routines is to call the equivalent
70 // range_* routines, check if the range is a singleton, and return it
71 // if so.
72 //
73 // The get_value_range method is currently provided for compatibility
74 // with vr-values. It will be deprecated when possible.
75
76 class range_query : public value_query
77 {
78 public:
79 range_query ();
80 virtual ~range_query ();
81
82 virtual tree value_of_expr (tree expr, gimple * = NULL) OVERRIDE;
83 virtual tree value_on_edge (edge, tree expr) OVERRIDE;
84 virtual tree value_of_stmt (gimple *, tree name = NULL) OVERRIDE;
85
86 // These are the range equivalents of the value_* methods. Instead
87 // of returning a singleton, they calculate a range and return it in
88 // R. TRUE is returned on success or FALSE if no range was found.
89 //
90 // Note that range_of_expr must always return TRUE unless ranges are
91 // unsupported for EXPR's type (supports_type_p is false).
92 virtual bool range_of_expr (irange &r, tree expr, gimple * = NULL) = 0;
93 virtual bool range_on_edge (irange &r, edge, tree expr);
94 virtual bool range_of_stmt (irange &r, gimple *, tree name = NULL);
95
96 // Query if there is any relation between SSA1 and SSA2.
97 relation_kind query_relation (gimple *s, tree ssa1, tree ssa2,
98 bool get_range = true);
99 relation_kind query_relation (edge e, tree ssa1, tree ssa2,
100 bool get_range = true);
101 // If present, Access relation oracle for more advanced uses.
oracle()102 inline relation_oracle *oracle () const { return m_oracle; }
103
104 // DEPRECATED: This method is used from vr-values. The plan is to
105 // rewrite all uses of it to the above API.
106 virtual const class value_range_equiv *get_value_range (const_tree,
107 gimple * = NULL);
108 virtual void dump (FILE *);
109
110 protected:
111 class value_range_equiv *allocate_value_range_equiv ();
112 void free_value_range_equiv (class value_range_equiv *);
113 bool get_tree_range (irange &r, tree expr, gimple *stmt);
114 bool get_arith_expr_range (irange &r, tree expr, gimple *stmt);
115 relation_oracle *m_oracle;
116
117 private:
118 class equiv_allocator *equiv_alloc;
119 };
120
121 // Global ranges for SSA names using SSA_NAME_RANGE_INFO.
122
123 class global_range_query : public range_query
124 {
125 public:
126 bool range_of_expr (irange &r, tree expr, gimple * = NULL) OVERRIDE;
127 };
128
129 extern global_range_query global_ranges;
130
131 inline range_query *
get_global_range_query()132 get_global_range_query ()
133 {
134 return &global_ranges;
135 }
136
137 /* Returns the currently active range access class. When there is no active
138 range class, global ranges are used. Never returns null. */
139
140 ATTRIBUTE_RETURNS_NONNULL inline range_query *
get_range_query(const struct function * fun)141 get_range_query (const struct function *fun)
142 {
143 return fun->x_range_query ? fun->x_range_query : &global_ranges;
144 }
145
146 extern value_range gimple_range_global (tree name);
147 extern bool update_global_range (irange &r, tree name);
148
149 #endif // GCC_QUERY_H
150