1 /* Source locations within string literals.
2 Copyright (C) 2016-2020 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "intl.h"
24 #include "diagnostic.h"
25 #include "cpplib.h"
26 #include "tree.h"
27 #include "langhooks.h"
28 #include "substring-locations.h"
29 #include "gcc-rich-location.h"
30
31 /* format_string_diagnostic_t's ctor, giving information for use by
32 the emit_warning* member functions, as follows:
33
34 They attempt to obtain precise location information within a string
35 literal from FMT_LOC.
36
37 Case 1: if substring location is available, and is within the range of
38 the format string itself, the primary location of the
39 diagnostic is the substring range obtained from FMT_LOC, with the
40 caret at the *end* of the substring range.
41
42 For example:
43
44 test.c:90:10: warning: problem with '%i' here [-Wformat=]
45 printf ("hello %i", msg);
46 ~^
47
48 Case 2: if the substring location is available, but is not within
49 the range of the format string, the primary location is that of the
50 format string, and a note is emitted showing the substring location.
51
52 For example:
53 test.c:90:10: warning: problem with '%i' here [-Wformat=]
54 printf("hello " INT_FMT " world", msg);
55 ^~~~~~~~~~~~~~~~~~~~~~~~~
56 test.c:19: note: format string is defined here
57 #define INT_FMT "%i"
58 ~^
59
60 Case 3: if precise substring information is unavailable, the primary
61 location is that of the whole string passed to FMT_LOC's constructor.
62 For example:
63
64 test.c:90:10: warning: problem with '%i' here [-Wformat=]
65 printf(fmt, msg);
66 ^~~
67
68 For each of cases 1-3, if param_loc is not UNKNOWN_LOCATION, then it is used
69 as a secondary range within the warning. For example, here it
70 is used with case 1:
71
72 test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
73 printf ("foo %s bar", long_i + long_j);
74 ~^ ~~~~~~~~~~~~~~~
75
76 and here with case 2:
77
78 test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
79 printf ("foo " STR_FMT " bar", long_i + long_j);
80 ^~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~
81 test.c:89:16: note: format string is defined here
82 #define STR_FMT "%s"
83 ~^
84
85 and with case 3:
86
87 test.c:90:10: warning: '%i' here, but arg 2 is "const char *' [-Wformat=]
88 printf(fmt, msg);
89 ^~~ ~~~
90
91 If non-NULL, then FMT_LABEL will be used to label the location within the
92 string for cases 1 and 2; if non-NULL, then PARAM_LABEL will be used to label
93 the parameter. For example with case 1:
94
95 test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
96 printf ("foo %s bar", long_i + long_j);
97 ~^ ~~~~~~~~~~~~~~~
98 |
99 int
100
101 and with case 2:
102
103 test.c:90:10: warning: problem with '%i' here [-Wformat=]
104 printf("hello " INT_FMT " world", msg);
105 ^~~~~~~~~~~~~~~~~~~~~~~~~
106 test.c:19: note: format string is defined here
107 #define INT_FMT "%i"
108 ~^
109 |
110 int
111
112 If CORRECTED_SUBSTRING is non-NULL, use it for cases 1 and 2 to provide
113 a fix-it hint, suggesting that it should replace the text within the
114 substring range. For example:
115
116 test.c:90:10: warning: problem with '%i' here [-Wformat=]
117 printf ("hello %i", msg);
118 ~^
119 %s
120
121 */
122
123 format_string_diagnostic_t::
format_string_diagnostic_t(const substring_loc & fmt_loc,const range_label * fmt_label,location_t param_loc,const range_label * param_label,const char * corrected_substring)124 format_string_diagnostic_t (const substring_loc &fmt_loc,
125 const range_label *fmt_label,
126 location_t param_loc,
127 const range_label *param_label,
128 const char *corrected_substring)
129 : m_fmt_loc (fmt_loc),
130 m_fmt_label (fmt_label),
131 m_param_loc (param_loc),
132 m_param_label (param_label),
133 m_corrected_substring (corrected_substring)
134 {
135 }
136
137 /* Emit a warning governed by option OPT, using SINGULAR_GMSGID as the
138 format string (or if PLURAL_GMSGID is different from SINGULAR_GMSGID,
139 using SINGULAR_GMSGID, PLURAL_GMSGID and N as arguments to ngettext)
140 and AP as its arguments.
141
142 Return true if a warning was emitted, false otherwise. */
143
144 bool
emit_warning_n_va(int opt,unsigned HOST_WIDE_INT n,const char * singular_gmsgid,const char * plural_gmsgid,va_list * ap)145 format_string_diagnostic_t::emit_warning_n_va (int opt,
146 unsigned HOST_WIDE_INT n,
147 const char *singular_gmsgid,
148 const char *plural_gmsgid,
149 va_list *ap) const
150 {
151 bool substring_within_range = false;
152 location_t primary_loc;
153 location_t fmt_substring_loc = UNKNOWN_LOCATION;
154 source_range fmt_loc_range
155 = get_range_from_loc (line_table, m_fmt_loc.get_fmt_string_loc ());
156 const char *err = m_fmt_loc.get_location (&fmt_substring_loc);
157 source_range fmt_substring_range
158 = get_range_from_loc (line_table, fmt_substring_loc);
159 if (err)
160 /* Case 3: unable to get substring location. */
161 primary_loc = m_fmt_loc.get_fmt_string_loc ();
162 else
163 {
164 if (fmt_substring_range.m_start >= fmt_loc_range.m_start
165 && fmt_substring_range.m_start <= fmt_loc_range.m_finish
166 && fmt_substring_range.m_finish >= fmt_loc_range.m_start
167 && fmt_substring_range.m_finish <= fmt_loc_range.m_finish)
168 /* Case 1. */
169 {
170 substring_within_range = true;
171 primary_loc = fmt_substring_loc;
172 }
173 else
174 /* Case 2. */
175 {
176 substring_within_range = false;
177 primary_loc = m_fmt_loc.get_fmt_string_loc ();
178 }
179 }
180
181 /* Only use fmt_label in the initial warning for case 1. */
182 const range_label *primary_label = NULL;
183 if (substring_within_range)
184 primary_label = m_fmt_label;
185
186 auto_diagnostic_group d;
187 gcc_rich_location richloc (primary_loc, primary_label);
188
189 if (m_param_loc != UNKNOWN_LOCATION)
190 richloc.add_range (m_param_loc, SHOW_RANGE_WITHOUT_CARET, m_param_label);
191
192 if (!err && m_corrected_substring && substring_within_range)
193 richloc.add_fixit_replace (fmt_substring_range, m_corrected_substring);
194
195 diagnostic_info diagnostic;
196 if (singular_gmsgid != plural_gmsgid)
197 {
198 unsigned long gtn;
199
200 if (sizeof n <= sizeof gtn)
201 gtn = n;
202 else
203 /* Use the largest number ngettext can handle, otherwise
204 preserve the six least significant decimal digits for
205 languages where the plural form depends on them. */
206 gtn = n <= ULONG_MAX ? n : n % 1000000LU + 1000000LU;
207
208 const char *text = ngettext (singular_gmsgid, plural_gmsgid, gtn);
209 diagnostic_set_info_translated (&diagnostic, text, ap, &richloc,
210 DK_WARNING);
211 }
212 else
213 diagnostic_set_info (&diagnostic, singular_gmsgid, ap, &richloc,
214 DK_WARNING);
215 diagnostic.option_index = opt;
216 bool warned = diagnostic_report_diagnostic (global_dc, &diagnostic);
217
218 if (!err && fmt_substring_loc && !substring_within_range)
219 /* Case 2. */
220 if (warned)
221 {
222 /* Use fmt_label in the note for case 2. */
223 rich_location substring_richloc (line_table, fmt_substring_loc,
224 m_fmt_label);
225 if (m_corrected_substring)
226 substring_richloc.add_fixit_replace (fmt_substring_range,
227 m_corrected_substring);
228 inform (&substring_richloc,
229 "format string is defined here");
230 }
231
232 return warned;
233 }
234
235 /* Singular-only version of the above. */
236
237 bool
emit_warning_va(int opt,const char * gmsgid,va_list * ap)238 format_string_diagnostic_t::emit_warning_va (int opt, const char *gmsgid,
239 va_list *ap) const
240 {
241 return emit_warning_n_va (opt, 0, gmsgid, gmsgid, ap);
242 }
243
244 /* Variadic version of the above (singular only). */
245
246 bool
emit_warning(int opt,const char * gmsgid,...)247 format_string_diagnostic_t::emit_warning (int opt, const char *gmsgid,
248 ...) const
249 {
250 va_list ap;
251 va_start (ap, gmsgid);
252 bool warned = emit_warning_va (opt, gmsgid, &ap);
253 va_end (ap);
254
255 return warned;
256 }
257
258 /* Variadic version of the above (singular vs plural). */
259
260 bool
emit_warning_n(int opt,unsigned HOST_WIDE_INT n,const char * singular_gmsgid,const char * plural_gmsgid,...)261 format_string_diagnostic_t::emit_warning_n (int opt, unsigned HOST_WIDE_INT n,
262 const char *singular_gmsgid,
263 const char *plural_gmsgid,
264 ...) const
265 {
266 va_list ap;
267 va_start (ap, plural_gmsgid);
268 bool warned = emit_warning_n_va (opt, n, singular_gmsgid, plural_gmsgid,
269 &ap);
270 va_end (ap);
271
272 return warned;
273 }
274
275 /* Attempt to determine the source location of the substring.
276 If successful, return NULL and write the source location to *OUT_LOC.
277 Otherwise return an error message. Error messages are intended
278 for GCC developers (to help debugging) rather than for end-users. */
279
280 const char *
get_location(location_t * out_loc)281 substring_loc::get_location (location_t *out_loc) const
282 {
283 gcc_assert (out_loc);
284 return lang_hooks.get_substring_location (*this, out_loc);
285 }
286