1 /* Functions to enable and disable individual warnings on an expression
2 and statement basis.
3 Copyright (C) 2021-2022 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
nowarn_spec_t(opt_code opt)36 nowarn_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_Warray_bounds_:
84 case OPT_Wformat_overflow_:
85 case OPT_Wformat_truncation_:
86 case OPT_Wrestrict:
87 case OPT_Wsizeof_pointer_memaccess:
88 case OPT_Wstrict_aliasing_:
89 case OPT_Wstringop_overflow_:
90 case OPT_Wstringop_overread:
91 case OPT_Wstringop_truncation:
92 m_bits = NW_ACCESS;
93 break;
94
95 /* Initialization warning group. */
96 case OPT_Winit_self:
97 case OPT_Wuninitialized:
98 case OPT_Wmaybe_uninitialized:
99 m_bits = NW_UNINIT;
100 break;
101
102 case OPT_Wdangling_pointer_:
103 case OPT_Wreturn_local_addr:
104 case OPT_Wuse_after_free_:
105 m_bits = NW_DANGLING;
106 break;
107
108 default:
109 /* A catchall group for everything else. */
110 m_bits = NW_OTHER;
111 }
112 }
113
114 /* A mapping from a 'location_t' to the warning spec set for it. */
115
116 GTY(()) nowarn_map_t *nowarn_map;
117
118 /* Return the no-warning disposition for location LOC and option OPT
119 or for all/any otions by default. */
120
121 bool
warning_suppressed_at(location_t loc,opt_code opt)122 warning_suppressed_at (location_t loc, opt_code opt /* = all_warnings */)
123 {
124 gcc_checking_assert (!RESERVED_LOCATION_P (loc));
125
126 if (!nowarn_map)
127 return false;
128
129 if (const nowarn_spec_t* const pspec = nowarn_map->get (loc))
130 {
131 const nowarn_spec_t optspec (opt);
132 return *pspec & optspec;
133 }
134
135 return false;
136 }
137
138 /* Change the supression of warnings for location LOC.
139 OPT controls which warnings are affected.
140 The wildcard OPT of -1 controls all warnings.
141 If SUPP is true (the default), enable the suppression of the warnings.
142 If SUPP is false, disable the suppression of the warnings. */
143
144 bool
suppress_warning_at(location_t loc,opt_code opt,bool supp)145 suppress_warning_at (location_t loc, opt_code opt /* = all_warnings */,
146 bool supp /* = true */)
147 {
148 gcc_checking_assert (!RESERVED_LOCATION_P (loc));
149
150 const nowarn_spec_t optspec (supp ? opt : opt_code ());
151
152 if (nowarn_spec_t *pspec = nowarn_map ? nowarn_map->get (loc) : NULL)
153 {
154 if (supp)
155 {
156 *pspec |= optspec;
157 return true;
158 }
159
160 *pspec &= optspec;
161 if (*pspec)
162 return true;
163
164 nowarn_map->remove (loc);
165 return false;
166 }
167
168 if (!supp || opt == no_warning)
169 return false;
170
171 if (!nowarn_map)
172 nowarn_map = nowarn_map_t::create_ggc (32);
173
174 nowarn_map->put (loc, optspec);
175 return true;
176 }
177
178 /* Copy the no-warning disposition from one location to another. */
179
180 void
copy_warning(location_t to,location_t from)181 copy_warning (location_t to, location_t from)
182 {
183 if (!nowarn_map)
184 return;
185
186 nowarn_spec_t *from_spec;
187 if (RESERVED_LOCATION_P (from))
188 from_spec = NULL;
189 else
190 from_spec = nowarn_map->get (from);
191 if (RESERVED_LOCATION_P (to))
192 /* We cannot set no-warning dispositions for 'to', so we have no chance but
193 lose those potentially set for 'from'. */
194 ;
195 else
196 {
197 if (from_spec)
198 {
199 nowarn_spec_t tem = *from_spec;
200 nowarn_map->put (to, tem);
201 }
202 else
203 nowarn_map->remove (to);
204 }
205 }
206