1/* Functions to enable and disable individual warnings on an expression
2 and statement basis.
3 Copyright (C) 2021-2023 Free Software Foundation, Inc.
4 Contributed by Martin Sebor <msebor@redhat.com>
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 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#include "config.h"
23#include "system.h"
24#include "coretypes.h"
25#include "backend.h"
26#include "bitmap.h"
27#include "tree.h"
28#include "cgraph.h"
29#include "hash-map.h"
30#include "diagnostic-spec.h"
31#include "pretty-print.h"
32#include "options.h"
33
34/* Initialize *THIS from warning option OPT. */
35
36nowarn_spec_t::nowarn_spec_t (opt_code opt)
37{
38 /* Create a very simple mapping based on testing and experience.
39 It should become more refined with time. */
40 switch (opt)
41 {
42 case no_warning:
43 m_bits = 0;
44 break;
45
46 case all_warnings:
47 m_bits = -1;
48 break;
49
50 /* Flow-sensitive warnings about pointer problems issued by both
51 front ends and the middle end. */
52 case OPT_Waddress:
53 case OPT_Wnonnull:
54 m_bits = NW_NONNULL;
55 break;
56
57 /* Flow-sensitive warnings about arithmetic overflow issued by both
58 front ends and the middle end. */
59 case OPT_Woverflow:
60 case OPT_Wshift_count_negative:
61 case OPT_Wshift_count_overflow:
62 case OPT_Wstrict_overflow:
63 m_bits = NW_VFLOW;
64 break;
65
66 /* Lexical warnings issued by front ends. */
67 case OPT_Wabi:
68 case OPT_Wlogical_op:
69 case OPT_Wparentheses:
70 case OPT_Wreturn_type:
71 case OPT_Wsizeof_array_div:
72 case OPT_Wstrict_aliasing:
73 case OPT_Wunused:
74 case OPT_Wunused_function:
75 case OPT_Wunused_but_set_variable:
76 case OPT_Wunused_variable:
77 case OPT_Wunused_but_set_parameter:
78 m_bits = NW_LEXICAL;
79 break;
80
81 /* Access warning group. */
82 case OPT_Warray_bounds_:
83 case OPT_Wformat_overflow_:
84 case OPT_Wformat_truncation_:
85 case OPT_Wrestrict:
86 case OPT_Wsizeof_pointer_memaccess:
87 case OPT_Wstrict_aliasing_:
88 case OPT_Wstringop_overflow_:
89 case OPT_Wstringop_overread:
90 case OPT_Wstringop_truncation:
91 m_bits = NW_ACCESS;
92 break;
93
94 /* Initialization warning group. */
95 case OPT_Winit_self:
96 case OPT_Wuninitialized:
97 case OPT_Wmaybe_uninitialized:
98 m_bits = NW_UNINIT;
99 break;
100
101 case OPT_Wdangling_pointer_:
102 case OPT_Wreturn_local_addr:
103 case OPT_Wuse_after_free_:
104 m_bits = NW_DANGLING;
105 break;
106
107 case OPT_Wpessimizing_move:
108 case OPT_Wredundant_move:
109 m_bits = NW_REDUNDANT;
110 break;
111
112 default:
113 /* A catchall group for everything else. */
114 m_bits = NW_OTHER;
115 }
116}
117
118/* A mapping from a 'location_t' to the warning spec set for it. */
119
120GTY(()) nowarn_map_t *nowarn_map;
121
122/* Return the no-warning disposition for location LOC and option OPT
123 or for all/any otions by default. */
124
125bool
126warning_suppressed_at (location_t loc, opt_code opt /* = all_warnings */)
127{
128 gcc_checking_assert (!RESERVED_LOCATION_P (loc));
129
130 if (!nowarn_map)
131 return false;
132
133 if (const nowarn_spec_t* const pspec = nowarn_map->get (k: loc))
134 {
135 const nowarn_spec_t optspec (opt);
136 return *pspec & optspec;
137 }
138
139 return false;
140}
141
142 /* Change the supression of warnings for location LOC.
143 OPT controls which warnings are affected.
144 The wildcard OPT of -1 controls all warnings.
145 If SUPP is true (the default), enable the suppression of the warnings.
146 If SUPP is false, disable the suppression of the warnings. */
147
148bool
149suppress_warning_at (location_t loc, opt_code opt /* = all_warnings */,
150 bool supp /* = true */)
151{
152 gcc_checking_assert (!RESERVED_LOCATION_P (loc));
153
154 const nowarn_spec_t optspec (supp ? opt : opt_code ());
155
156 if (nowarn_spec_t *pspec = nowarn_map ? nowarn_map->get (k: loc) : NULL)
157 {
158 if (supp)
159 {
160 *pspec |= optspec;
161 return true;
162 }
163
164 *pspec &= optspec;
165 if (*pspec)
166 return true;
167
168 nowarn_map->remove (k: loc);
169 return false;
170 }
171
172 if (!supp || opt == no_warning)
173 return false;
174
175 if (!nowarn_map)
176 nowarn_map = nowarn_map_t::create_ggc (size: 32);
177
178 nowarn_map->put (k: loc, v: optspec);
179 return true;
180}
181
182/* Copy the no-warning disposition from one location to another. */
183
184void
185copy_warning (location_t to, location_t from)
186{
187 if (!nowarn_map)
188 return;
189
190 nowarn_spec_t *from_spec;
191 if (RESERVED_LOCATION_P (from))
192 from_spec = NULL;
193 else
194 from_spec = nowarn_map->get (k: from);
195 if (RESERVED_LOCATION_P (to))
196 /* We cannot set no-warning dispositions for 'to', so we have no chance but
197 lose those potentially set for 'from'. */
198 ;
199 else
200 {
201 if (from_spec)
202 {
203 nowarn_spec_t tem = *from_spec;
204 nowarn_map->put (k: to, v: tem);
205 }
206 else
207 nowarn_map->remove (k: to);
208 }
209}
210

source code of gcc/diagnostic-spec.cc