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c3388e62 | 1 | /* Implementation of -Wmisleading-indentation |
a945c346 | 2 | Copyright (C) 2015-2024 Free Software Foundation, Inc. |
c3388e62 DM |
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 "tm.h" | |
2adfab87 | 24 | #include "c-common.h" |
992118a1 | 25 | #include "c-indentation.h" |
10fcc142 | 26 | #include "selftest.h" |
004bb936 | 27 | #include "diagnostic.h" |
c3388e62 | 28 | |
64b23c13 DM |
29 | /* Round up VIS_COLUMN to nearest tab stop. */ |
30 | ||
31 | static unsigned int | |
10fcc142 | 32 | next_tab_stop (unsigned int vis_column, unsigned int tab_width) |
64b23c13 | 33 | { |
64b23c13 DM |
34 | vis_column = ((vis_column + tab_width) / tab_width) * tab_width; |
35 | return vis_column; | |
36 | } | |
37 | ||
c3388e62 DM |
38 | /* Convert libcpp's notion of a column (a 1-based char count) to |
39 | the "visual column" (0-based column, respecting tabs), by reading the | |
40 | relevant line. | |
1a1e101f | 41 | |
c3388e62 | 42 | Returns true if a conversion was possible, writing the result to OUT, |
1a1e101f PP |
43 | otherwise returns false. If FIRST_NWS is not NULL, then write to it |
44 | the visual column corresponding to the first non-whitespace character | |
10fcc142 | 45 | on the line (up to or before EXPLOC). */ |
c3388e62 DM |
46 | |
47 | static bool | |
1bdd665a DM |
48 | get_visual_column (file_cache &fc, |
49 | expanded_location exploc, | |
1a1e101f | 50 | unsigned int *out, |
10fcc142 DM |
51 | unsigned int *first_nws, |
52 | unsigned int tab_width) | |
c3388e62 | 53 | { |
1bdd665a | 54 | char_span line = fc.get_source_line (exploc.file, exploc.line); |
c3388e62 DM |
55 | if (!line) |
56 | return false; | |
10fcc142 DM |
57 | if ((size_t)exploc.column > line.length ()) |
58 | return false; | |
c3388e62 DM |
59 | unsigned int vis_column = 0; |
60 | for (int i = 1; i < exploc.column; i++) | |
61 | { | |
62 | unsigned char ch = line[i - 1]; | |
1a1e101f PP |
63 | |
64 | if (first_nws != NULL && !ISSPACE (ch)) | |
65 | { | |
66 | *first_nws = vis_column; | |
67 | first_nws = NULL; | |
68 | } | |
69 | ||
c3388e62 | 70 | if (ch == '\t') |
10fcc142 | 71 | vis_column = next_tab_stop (vis_column, tab_width); |
c3388e62 DM |
72 | else |
73 | vis_column++; | |
74 | } | |
75 | ||
1a1e101f PP |
76 | if (first_nws != NULL) |
77 | *first_nws = vis_column; | |
c3388e62 | 78 | |
1a1e101f | 79 | *out = vis_column; |
c3388e62 DM |
80 | return true; |
81 | } | |
82 | ||
64b23c13 DM |
83 | /* Attempt to determine the first non-whitespace character in line LINE_NUM |
84 | of source line FILE. | |
85 | ||
86 | If this is possible, return true and write its "visual column" to | |
87 | *FIRST_NWS. | |
88 | Otherwise, return false, leaving *FIRST_NWS untouched. */ | |
c3388e62 DM |
89 | |
90 | static bool | |
1bdd665a DM |
91 | get_first_nws_vis_column (file_cache &fc, |
92 | const char *file, int line_num, | |
10fcc142 DM |
93 | unsigned int *first_nws, |
94 | unsigned int tab_width) | |
c3388e62 | 95 | { |
64b23c13 DM |
96 | gcc_assert (first_nws); |
97 | ||
1bdd665a | 98 | char_span line = fc.get_source_line (file, line_num); |
c3388e62 DM |
99 | if (!line) |
100 | return false; | |
64b23c13 | 101 | unsigned int vis_column = 0; |
7761dfbe | 102 | for (size_t i = 1; i < line.length (); i++) |
64b23c13 DM |
103 | { |
104 | unsigned char ch = line[i - 1]; | |
c3388e62 | 105 | |
64b23c13 DM |
106 | if (!ISSPACE (ch)) |
107 | { | |
108 | *first_nws = vis_column; | |
109 | return true; | |
110 | } | |
c3388e62 | 111 | |
64b23c13 | 112 | if (ch == '\t') |
10fcc142 | 113 | vis_column = next_tab_stop (vis_column, tab_width); |
64b23c13 DM |
114 | else |
115 | vis_column++; | |
c3388e62 DM |
116 | } |
117 | ||
64b23c13 | 118 | /* No non-whitespace characters found. */ |
c3388e62 DM |
119 | return false; |
120 | } | |
121 | ||
64b23c13 | 122 | /* Determine if there is an unindent/outdent between |
c3388e62 | 123 | BODY_EXPLOC and NEXT_STMT_EXPLOC, to ensure that we don't |
64b23c13 DM |
124 | issue a warning for cases like the following: |
125 | ||
126 | (1) Preprocessor logic | |
c3388e62 DM |
127 | |
128 | if (flagA) | |
129 | foo (); | |
130 | ^ BODY_EXPLOC | |
131 | #if SOME_CONDITION_THAT_DOES_NOT_HOLD | |
132 | if (flagB) | |
133 | #endif | |
134 | bar (); | |
135 | ^ NEXT_STMT_EXPLOC | |
136 | ||
64b23c13 DM |
137 | "bar ();" is visually aligned below "foo ();" and |
138 | is (as far as the parser sees) the next token, but | |
139 | this isn't misleading to a human reader. | |
c3388e62 | 140 | |
64b23c13 | 141 | (2) Empty macro with bad indentation |
c3388e62 | 142 | |
64b23c13 DM |
143 | In the following, the |
144 | "if (i > 0)" | |
145 | is poorly indented, and ought to be on the same column as | |
146 | "engine_ref_debug(e, 0, -1)" | |
147 | However, it is not misleadingly indented, due to the presence | |
148 | of that macro. | |
c3388e62 | 149 | |
64b23c13 DM |
150 | #define engine_ref_debug(X, Y, Z) |
151 | ||
152 | if (locked) | |
153 | i = foo (0); | |
154 | else | |
155 | i = foo (1); | |
156 | engine_ref_debug(e, 0, -1) | |
157 | if (i > 0) | |
158 | return 1; | |
c3388e62 | 159 | |
64b23c13 | 160 | Return true if such an unindent/outdent is detected. */ |
c3388e62 | 161 | |
64b23c13 | 162 | static bool |
1bdd665a DM |
163 | detect_intervening_unindent (file_cache &fc, |
164 | const char *file, | |
64b23c13 DM |
165 | int body_line, |
166 | int next_stmt_line, | |
10fcc142 DM |
167 | unsigned int vis_column, |
168 | unsigned int tab_width) | |
64b23c13 DM |
169 | { |
170 | gcc_assert (file); | |
171 | gcc_assert (next_stmt_line > body_line); | |
172 | ||
173 | for (int line = body_line + 1; line < next_stmt_line; line++) | |
174 | { | |
175 | unsigned int line_vis_column; | |
1bdd665a | 176 | if (get_first_nws_vis_column (fc, file, line, &line_vis_column, tab_width)) |
64b23c13 DM |
177 | if (line_vis_column < vis_column) |
178 | return true; | |
179 | } | |
c3388e62 DM |
180 | |
181 | /* Not found. */ | |
182 | return false; | |
183 | } | |
184 | ||
185 | ||
186 | /* Helper function for warn_for_misleading_indentation; see | |
187 | description of that function below. */ | |
188 | ||
189 | static bool | |
992118a1 PP |
190 | should_warn_for_misleading_indentation (const token_indent_info &guard_tinfo, |
191 | const token_indent_info &body_tinfo, | |
192 | const token_indent_info &next_tinfo) | |
c3388e62 | 193 | { |
c3388e62 DM |
194 | /* Don't attempt to compare indentation if #line or # 44 "file"-style |
195 | directives are present, suggesting generated code. | |
196 | ||
197 | All bets are off if these are present: the file that the #line | |
198 | directive could have an entirely different coding layout to C/C++ | |
199 | (e.g. .md files). | |
200 | ||
201 | To determine if a #line is present, in theory we could look for a | |
202 | map with reason == LC_RENAME_VERBATIM. However, if there has | |
203 | subsequently been a long line requiring a column number larger than | |
204 | that representable by the original LC_RENAME_VERBATIM map, then | |
205 | we'll have a map with reason LC_RENAME. | |
206 | Rather than attempting to search all of the maps for a | |
207 | LC_RENAME_VERBATIM, instead we have libcpp set a flag whenever one | |
208 | is seen, and we check for the flag here. | |
209 | */ | |
210 | if (line_table->seen_line_directive) | |
211 | return false; | |
212 | ||
b3a77f21 MP |
213 | /* We can't usefully warn about do-while and switch statements since the |
214 | bodies of these statements are always explicitly delimited at both ends, | |
215 | so control flow is quite obvious. */ | |
216 | if (guard_tinfo.keyword == RID_DO | |
217 | || guard_tinfo.keyword == RID_SWITCH) | |
21efdd80 PP |
218 | return false; |
219 | ||
992118a1 PP |
220 | /* If the token following the body is a close brace or an "else" |
221 | then while indentation may be sloppy, there is not much ambiguity | |
222 | about control flow, e.g. | |
223 | ||
224 | if (foo) <- GUARD | |
225 | bar (); <- BODY | |
226 | else baz (); <- NEXT | |
227 | ||
228 | { | |
229 | while (foo) <- GUARD | |
230 | bar (); <- BODY | |
231 | } <- NEXT | |
232 | baz (); | |
233 | */ | |
4839de55 | 234 | enum cpp_ttype next_tok_type = next_tinfo.type; |
992118a1 PP |
235 | if (next_tok_type == CPP_CLOSE_BRACE |
236 | || next_tinfo.keyword == RID_ELSE) | |
c3388e62 DM |
237 | return false; |
238 | ||
8ebca419 PP |
239 | /* Likewise, if the body of the guard is a compound statement then control |
240 | flow is quite visually explicit regardless of the code's possibly poor | |
241 | indentation, e.g. | |
242 | ||
243 | while (foo) <- GUARD | |
244 | { <- BODY | |
245 | bar (); | |
246 | } | |
247 | baz (); <- NEXT | |
248 | ||
249 | Things only get muddy when the body of the guard does not have | |
250 | braces, e.g. | |
251 | ||
252 | if (foo) <- GUARD | |
253 | bar (); <- BODY | |
254 | baz (); <- NEXT | |
255 | */ | |
4839de55 | 256 | enum cpp_ttype body_type = body_tinfo.type; |
8ebca419 PP |
257 | if (body_type == CPP_OPEN_BRACE) |
258 | return false; | |
259 | ||
c3388e62 DM |
260 | /* Don't warn here about spurious semicolons. */ |
261 | if (next_tok_type == CPP_SEMICOLON) | |
262 | return false; | |
263 | ||
4839de55 PP |
264 | location_t guard_loc = guard_tinfo.location; |
265 | location_t body_loc = body_tinfo.location; | |
266 | location_t next_stmt_loc = next_tinfo.location; | |
267 | ||
268 | /* Resolve each token location to the respective macro expansion | |
269 | point that produced the token. */ | |
270 | if (linemap_location_from_macro_expansion_p (line_table, guard_loc)) | |
271 | guard_loc = linemap_resolve_location (line_table, guard_loc, | |
272 | LRK_MACRO_EXPANSION_POINT, NULL); | |
273 | if (linemap_location_from_macro_expansion_p (line_table, body_loc)) | |
274 | body_loc = linemap_resolve_location (line_table, body_loc, | |
275 | LRK_MACRO_EXPANSION_POINT, NULL); | |
276 | if (linemap_location_from_macro_expansion_p (line_table, next_stmt_loc)) | |
277 | next_stmt_loc = linemap_resolve_location (line_table, next_stmt_loc, | |
278 | LRK_MACRO_EXPANSION_POINT, NULL); | |
279 | ||
280 | /* When all three tokens are produced from a single macro expansion, we | |
281 | instead consider their loci inside that macro's definition. */ | |
282 | if (guard_loc == body_loc && body_loc == next_stmt_loc) | |
283 | { | |
284 | const line_map *guard_body_common_map | |
285 | = first_map_in_common (line_table, | |
286 | guard_tinfo.location, body_tinfo.location, | |
287 | &guard_loc, &body_loc); | |
288 | const line_map *body_next_common_map | |
289 | = first_map_in_common (line_table, | |
290 | body_tinfo.location, next_tinfo.location, | |
291 | &body_loc, &next_stmt_loc); | |
292 | ||
293 | /* Punt on complicated nesting of macros. */ | |
294 | if (guard_body_common_map != body_next_common_map) | |
295 | return false; | |
296 | ||
297 | guard_loc = linemap_resolve_location (line_table, guard_loc, | |
298 | LRK_MACRO_DEFINITION_LOCATION, NULL); | |
299 | body_loc = linemap_resolve_location (line_table, body_loc, | |
300 | LRK_MACRO_DEFINITION_LOCATION, NULL); | |
301 | next_stmt_loc = linemap_resolve_location (line_table, next_stmt_loc, | |
302 | LRK_MACRO_DEFINITION_LOCATION, | |
303 | NULL); | |
304 | } | |
305 | ||
6ac48155 DM |
306 | expanded_location body_exploc = expand_location (body_loc); |
307 | expanded_location next_stmt_exploc = expand_location (next_stmt_loc); | |
8ebca419 | 308 | expanded_location guard_exploc = expand_location (guard_loc); |
c3388e62 | 309 | |
4394b1ce PP |
310 | /* PR c++/68819: if the column number is zero, we presumably |
311 | had a location_t > LINE_MAP_MAX_LOCATION_WITH_COLS, and so | |
312 | we have no column information. */ | |
313 | if (!guard_exploc.column || !body_exploc.column || !next_stmt_exploc.column) | |
314 | { | |
315 | static bool issued_note = false; | |
316 | if (!issued_note) | |
317 | { | |
318 | /* Notify the user the first time this happens. */ | |
319 | issued_note = true; | |
320 | inform (guard_loc, | |
321 | "%<-Wmisleading-indentation%> is disabled from this point" | |
322 | " onwards, since column-tracking was disabled due to" | |
323 | " the size of the code/headers"); | |
324 | if (!flag_large_source_files) | |
325 | inform (guard_loc, | |
326 | "adding %<-flarge-source-files%> will allow for more" | |
327 | " column-tracking support, at the expense of compilation" | |
328 | " time and memory"); | |
329 | } | |
330 | return false; | |
331 | } | |
332 | ||
333 | /* Give up if the loci are not all distinct. */ | |
334 | if (guard_loc == body_loc || body_loc == next_stmt_loc) | |
335 | return false; | |
336 | ||
8200cd97 | 337 | const unsigned int tab_width = global_dc->m_tabstop; |
10fcc142 | 338 | |
c3388e62 DM |
339 | /* They must be in the same file. */ |
340 | if (next_stmt_exploc.file != body_exploc.file) | |
341 | return false; | |
342 | ||
1bdd665a DM |
343 | file_cache &fc = global_dc->get_file_cache (); |
344 | ||
c3388e62 DM |
345 | /* If NEXT_STMT_LOC and BODY_LOC are on the same line, consider |
346 | the location of the guard. | |
347 | ||
348 | Cases where we want to issue a warning: | |
349 | ||
350 | if (flag) | |
351 | foo (); bar (); | |
352 | ^ WARN HERE | |
353 | ||
354 | if (flag) foo (); bar (); | |
355 | ^ WARN HERE | |
356 | ||
8ebca419 PP |
357 | |
358 | if (flag) ; { | |
359 | ^ WARN HERE | |
360 | ||
361 | if (flag) | |
362 | ; { | |
363 | ^ WARN HERE | |
364 | ||
c3388e62 DM |
365 | Cases where we don't want to issue a warning: |
366 | ||
367 | various_code (); if (flag) foo (); bar (); more_code (); | |
368 | ^ DON'T WARN HERE. */ | |
369 | if (next_stmt_exploc.line == body_exploc.line) | |
370 | { | |
c3388e62 DM |
371 | if (guard_exploc.file != body_exploc.file) |
372 | return true; | |
373 | if (guard_exploc.line < body_exploc.line) | |
374 | /* The guard is on a line before a line that contains both | |
375 | the body and the next stmt. */ | |
376 | return true; | |
377 | else if (guard_exploc.line == body_exploc.line) | |
378 | { | |
379 | /* They're all on the same line. */ | |
380 | gcc_assert (guard_exploc.file == next_stmt_exploc.file); | |
381 | gcc_assert (guard_exploc.line == next_stmt_exploc.line); | |
1a1e101f PP |
382 | unsigned int guard_vis_column; |
383 | unsigned int guard_line_first_nws; | |
1bdd665a DM |
384 | if (!get_visual_column (fc, |
385 | guard_exploc, | |
1a1e101f | 386 | &guard_vis_column, |
10fcc142 | 387 | &guard_line_first_nws, tab_width)) |
1a1e101f | 388 | return false; |
c3388e62 DM |
389 | /* Heuristic: only warn if the guard is the first thing |
390 | on its line. */ | |
1a1e101f | 391 | if (guard_vis_column == guard_line_first_nws) |
c3388e62 DM |
392 | return true; |
393 | } | |
394 | } | |
395 | ||
396 | /* If NEXT_STMT_LOC is on a line after BODY_LOC, consider | |
397 | their relative locations, and of the guard. | |
398 | ||
399 | Cases where we want to issue a warning: | |
400 | if (flag) | |
401 | foo (); | |
402 | bar (); | |
403 | ^ WARN HERE | |
404 | ||
405 | Cases where we don't want to issue a warning: | |
406 | if (flag) | |
407 | foo (); | |
408 | bar (); | |
409 | ^ DON'T WARN HERE (autogenerated code?) | |
410 | ||
411 | if (flagA) | |
412 | foo (); | |
413 | #if SOME_CONDITION_THAT_DOES_NOT_HOLD | |
414 | if (flagB) | |
415 | #endif | |
416 | bar (); | |
417 | ^ DON'T WARN HERE | |
6ac48155 | 418 | |
8ebca419 PP |
419 | if (flag) |
420 | ; | |
421 | foo (); | |
422 | ^ DON'T WARN HERE | |
c589e975 DM |
423 | |
424 | #define emit | |
425 | if (flag) | |
426 | foo (); | |
427 | emit bar (); | |
428 | ^ DON'T WARN HERE | |
429 | ||
c3388e62 DM |
430 | */ |
431 | if (next_stmt_exploc.line > body_exploc.line) | |
432 | { | |
433 | /* Determine if GUARD_LOC and NEXT_STMT_LOC are aligned on the same | |
434 | "visual column"... */ | |
435 | unsigned int next_stmt_vis_column; | |
c589e975 | 436 | unsigned int next_stmt_line_first_nws; |
c3388e62 | 437 | unsigned int body_vis_column; |
8ebca419 | 438 | unsigned int body_line_first_nws; |
d5398058 PP |
439 | unsigned int guard_vis_column; |
440 | unsigned int guard_line_first_nws; | |
c3388e62 DM |
441 | /* If we can't determine it, don't issue a warning. This is sometimes |
442 | the case for input files containing #line directives, and these | |
443 | are often for autogenerated sources (e.g. from .md files), where | |
444 | it's not clear that it's meaningful to look at indentation. */ | |
1bdd665a DM |
445 | if (!get_visual_column (fc, |
446 | next_stmt_exploc, | |
c7df95d8 | 447 | &next_stmt_vis_column, |
10fcc142 | 448 | &next_stmt_line_first_nws, tab_width)) |
c3388e62 | 449 | return false; |
1bdd665a DM |
450 | if (!get_visual_column (fc, |
451 | body_exploc, | |
8ebca419 | 452 | &body_vis_column, |
10fcc142 | 453 | &body_line_first_nws, tab_width)) |
c3388e62 | 454 | return false; |
1bdd665a DM |
455 | if (!get_visual_column (fc, |
456 | guard_exploc, | |
d5398058 | 457 | &guard_vis_column, |
10fcc142 | 458 | &guard_line_first_nws, tab_width)) |
d5398058 PP |
459 | return false; |
460 | ||
c589e975 DM |
461 | /* If the line where the next stmt starts has non-whitespace |
462 | on it before the stmt, then don't warn: | |
463 | #define emit | |
464 | if (flag) | |
465 | foo (); | |
466 | emit bar (); | |
467 | ^ DON'T WARN HERE | |
468 | (PR c/69122). */ | |
469 | if (next_stmt_line_first_nws < next_stmt_vis_column) | |
470 | return false; | |
471 | ||
8ebca419 PP |
472 | if ((body_type != CPP_SEMICOLON |
473 | && next_stmt_vis_column == body_vis_column) | |
474 | /* As a special case handle the case where the body is a semicolon | |
475 | that may be hidden by a preceding comment, e.g. */ | |
476 | ||
477 | // if (p) | |
478 | // /* blah */; | |
479 | // foo (1); | |
480 | ||
481 | /* by looking instead at the column of the first non-whitespace | |
482 | character on the body line. */ | |
483 | || (body_type == CPP_SEMICOLON | |
484 | && body_exploc.line > guard_exploc.line | |
485 | && body_line_first_nws != body_vis_column | |
d5398058 | 486 | && next_stmt_vis_column > guard_line_first_nws)) |
c3388e62 | 487 | { |
8ebca419 PP |
488 | /* Don't warn if they are aligned on the same column |
489 | as the guard itself (suggesting autogenerated code that doesn't | |
729526f5 DM |
490 | bother indenting at all). |
491 | For "else" clauses, we consider the column of the first | |
8ebca419 PP |
492 | non-whitespace character on the guard line instead of the column |
493 | of the actual guard token itself because it is more sensible. | |
494 | Consider: | |
495 | ||
496 | if (p) { | |
497 | foo (1); | |
498 | } else // GUARD | |
499 | foo (2); // BODY | |
500 | foo (3); // NEXT | |
501 | ||
502 | and: | |
503 | ||
504 | if (p) | |
505 | foo (1); | |
506 | } else // GUARD | |
507 | foo (2); // BODY | |
508 | foo (3); // NEXT | |
509 | ||
729526f5 | 510 | If we just used the column of the "else" token, we would warn on |
8ebca419 PP |
511 | the first example and not warn on the second. But we want the |
512 | exact opposite to happen: to not warn on the first example (which | |
513 | is probably autogenerated) and to warn on the second (whose | |
514 | indentation is misleading). Using the column of the first | |
515 | non-whitespace character on the guard line makes that | |
516 | happen. */ | |
729526f5 DM |
517 | unsigned int guard_column = (guard_tinfo.keyword == RID_ELSE |
518 | ? guard_line_first_nws | |
519 | : guard_vis_column); | |
520 | if (guard_column == body_vis_column) | |
c3388e62 DM |
521 | return false; |
522 | ||
8ebca419 PP |
523 | /* We may have something like: |
524 | ||
525 | if (p) | |
526 | { | |
527 | foo (1); | |
528 | } else // GUARD | |
529 | foo (2); // BODY | |
530 | foo (3); // NEXT | |
531 | ||
532 | in which case the columns are not aligned but the code is not | |
729526f5 DM |
533 | misleadingly indented. If the column of the body isn't indented |
534 | more than the guard line then don't warn. */ | |
535 | if (body_vis_column <= guard_line_first_nws) | |
6ac48155 DM |
536 | return false; |
537 | ||
64b23c13 DM |
538 | /* Don't warn if there is an unindent between the two statements. */ |
539 | int vis_column = MIN (next_stmt_vis_column, body_vis_column); | |
1bdd665a DM |
540 | if (detect_intervening_unindent (fc, |
541 | body_exploc.file, body_exploc.line, | |
64b23c13 | 542 | next_stmt_exploc.line, |
10fcc142 | 543 | vis_column, tab_width)) |
c3388e62 DM |
544 | return false; |
545 | ||
546 | /* Otherwise, they are visually aligned: issue a warning. */ | |
547 | return true; | |
548 | } | |
8ebca419 PP |
549 | |
550 | /* Also issue a warning for code having the form: | |
551 | ||
552 | if (flag); | |
553 | foo (); | |
554 | ||
555 | while (flag); | |
556 | { | |
557 | ... | |
558 | } | |
559 | ||
560 | for (...); | |
561 | { | |
562 | ... | |
563 | } | |
564 | ||
565 | if (flag) | |
566 | ; | |
567 | else if (flag); | |
568 | foo (); | |
569 | ||
570 | where the semicolon at the end of each guard is most likely spurious. | |
571 | ||
572 | But do not warn on: | |
573 | ||
574 | for (..); | |
575 | foo (); | |
576 | ||
577 | where the next statement is aligned with the guard. | |
578 | */ | |
579 | if (body_type == CPP_SEMICOLON) | |
580 | { | |
581 | if (body_exploc.line == guard_exploc.line) | |
582 | { | |
8ebca419 PP |
583 | if (next_stmt_vis_column > guard_line_first_nws |
584 | || (next_tok_type == CPP_OPEN_BRACE | |
6b95d7cc | 585 | && next_stmt_vis_column == guard_line_first_nws)) |
8ebca419 PP |
586 | return true; |
587 | } | |
588 | } | |
c3388e62 DM |
589 | } |
590 | ||
591 | return false; | |
592 | } | |
593 | ||
992118a1 PP |
594 | /* Return the string identifier corresponding to the given guard token. */ |
595 | ||
3e2becc4 MP |
596 | const char * |
597 | guard_tinfo_to_string (enum rid keyword) | |
992118a1 | 598 | { |
3e2becc4 | 599 | switch (keyword) |
992118a1 PP |
600 | { |
601 | case RID_FOR: | |
602 | return "for"; | |
603 | case RID_ELSE: | |
604 | return "else"; | |
605 | case RID_IF: | |
606 | return "if"; | |
607 | case RID_WHILE: | |
608 | return "while"; | |
609 | case RID_DO: | |
610 | return "do"; | |
3e2becc4 MP |
611 | case RID_SWITCH: |
612 | return "switch"; | |
992118a1 PP |
613 | default: |
614 | gcc_unreachable (); | |
615 | } | |
616 | } | |
617 | ||
c3388e62 DM |
618 | /* Called by the C/C++ frontends when we have a guarding statement at |
619 | GUARD_LOC containing a statement at BODY_LOC, where the block wasn't | |
620 | written using braces, like this: | |
621 | ||
622 | if (flag) | |
623 | foo (); | |
624 | ||
625 | along with the location of the next token, at NEXT_STMT_LOC, | |
626 | so that we can detect followup statements that are within | |
627 | the same "visual block" as the guarded statement, but which | |
628 | aren't logically grouped within the guarding statement, such | |
629 | as: | |
630 | ||
631 | GUARD_LOC | |
632 | | | |
633 | V | |
634 | if (flag) | |
635 | foo (); <- BODY_LOC | |
636 | bar (); <- NEXT_STMT_LOC | |
637 | ||
638 | In the above, "bar ();" isn't guarded by the "if", but | |
639 | is indented to misleadingly suggest that it is in the same | |
640 | block as "foo ();". | |
641 | ||
642 | GUARD_KIND identifies the kind of clause e.g. "if", "else" etc. */ | |
643 | ||
644 | void | |
992118a1 PP |
645 | warn_for_misleading_indentation (const token_indent_info &guard_tinfo, |
646 | const token_indent_info &body_tinfo, | |
647 | const token_indent_info &next_tinfo) | |
c3388e62 | 648 | { |
773ce42e DM |
649 | /* Early reject for the case where -Wmisleading-indentation is disabled, |
650 | to avoid doing work only to have the warning suppressed inside the | |
651 | diagnostic machinery. */ | |
652 | if (!warn_misleading_indentation) | |
653 | return; | |
654 | ||
992118a1 PP |
655 | if (should_warn_for_misleading_indentation (guard_tinfo, |
656 | body_tinfo, | |
657 | next_tinfo)) | |
658 | { | |
097f82ec | 659 | auto_diagnostic_group d; |
5c240f4d DM |
660 | if (warning_at (guard_tinfo.location, OPT_Wmisleading_indentation, |
661 | "this %qs clause does not guard...", | |
3e2becc4 | 662 | guard_tinfo_to_string (guard_tinfo.keyword))) |
5c240f4d | 663 | inform (next_tinfo.location, |
a02fa805 DM |
664 | "...this statement, but the latter is misleadingly indented" |
665 | " as if it were guarded by the %qs", | |
3e2becc4 | 666 | guard_tinfo_to_string (guard_tinfo.keyword)); |
992118a1 | 667 | } |
c3388e62 | 668 | } |
10fcc142 DM |
669 | |
670 | #if CHECKING_P | |
671 | ||
672 | namespace selftest { | |
673 | ||
674 | /* Verify that next_tab_stop works as expected. */ | |
675 | ||
676 | static void | |
677 | test_next_tab_stop () | |
678 | { | |
679 | const unsigned int tab_width = 8; | |
680 | ||
681 | ASSERT_EQ (next_tab_stop (0, tab_width), 8); | |
682 | ASSERT_EQ (next_tab_stop (1, tab_width), 8); | |
683 | ASSERT_EQ (next_tab_stop (7, tab_width), 8); | |
684 | ||
685 | ASSERT_EQ (next_tab_stop (8, tab_width), 16); | |
686 | ASSERT_EQ (next_tab_stop (9, tab_width), 16); | |
687 | ASSERT_EQ (next_tab_stop (15, tab_width), 16); | |
688 | ||
689 | ASSERT_EQ (next_tab_stop (16, tab_width), 24); | |
690 | ASSERT_EQ (next_tab_stop (17, tab_width), 24); | |
691 | ASSERT_EQ (next_tab_stop (23, tab_width), 24); | |
692 | } | |
693 | ||
694 | /* Verify that the given call to get_visual_column succeeds, with | |
695 | the given results. */ | |
696 | ||
697 | static void | |
698 | assert_get_visual_column_succeeds (const location &loc, | |
1bdd665a | 699 | file_cache &fc, |
10fcc142 DM |
700 | const char *file, int line, int column, |
701 | const unsigned int tab_width, | |
702 | unsigned int expected_visual_column, | |
703 | unsigned int expected_first_nws) | |
704 | { | |
705 | expanded_location exploc; | |
706 | exploc.file = file; | |
707 | exploc.line = line; | |
708 | exploc.column = column; | |
709 | exploc.data = NULL; | |
710 | exploc.sysp = false; | |
711 | unsigned int actual_visual_column; | |
712 | unsigned int actual_first_nws; | |
1bdd665a DM |
713 | bool result = get_visual_column (fc, |
714 | exploc, | |
10fcc142 DM |
715 | &actual_visual_column, |
716 | &actual_first_nws, tab_width); | |
717 | ASSERT_TRUE_AT (loc, result); | |
718 | ASSERT_EQ_AT (loc, actual_visual_column, expected_visual_column); | |
719 | ASSERT_EQ_AT (loc, actual_first_nws, expected_first_nws); | |
720 | } | |
721 | ||
722 | /* Verify that the given call to get_visual_column succeeds, with | |
723 | the given results. */ | |
724 | ||
1bdd665a DM |
725 | #define ASSERT_GET_VISUAL_COLUMN_SUCCEEDS(FILE_CACHE, \ |
726 | FILENAME, LINE, COLUMN, \ | |
10fcc142 DM |
727 | TAB_WIDTH, \ |
728 | EXPECTED_VISUAL_COLUMN, \ | |
729 | EXPECTED_FIRST_NWS) \ | |
730 | SELFTEST_BEGIN_STMT \ | |
731 | assert_get_visual_column_succeeds (SELFTEST_LOCATION, \ | |
1bdd665a | 732 | FILE_CACHE, \ |
10fcc142 DM |
733 | FILENAME, LINE, COLUMN, \ |
734 | TAB_WIDTH, \ | |
735 | EXPECTED_VISUAL_COLUMN, \ | |
736 | EXPECTED_FIRST_NWS); \ | |
737 | SELFTEST_END_STMT | |
738 | ||
739 | /* Verify that the given call to get_visual_column fails gracefully. */ | |
740 | ||
741 | static void | |
742 | assert_get_visual_column_fails (const location &loc, | |
1bdd665a | 743 | file_cache &fc, |
10fcc142 DM |
744 | const char *file, int line, int column, |
745 | const unsigned int tab_width) | |
746 | { | |
747 | expanded_location exploc; | |
748 | exploc.file = file; | |
749 | exploc.line = line; | |
750 | exploc.column = column; | |
751 | exploc.data = NULL; | |
752 | exploc.sysp = false; | |
753 | unsigned int actual_visual_column; | |
754 | unsigned int actual_first_nws; | |
1bdd665a DM |
755 | bool result = get_visual_column (fc, |
756 | exploc, | |
10fcc142 DM |
757 | &actual_visual_column, |
758 | &actual_first_nws, tab_width); | |
759 | ASSERT_FALSE_AT (loc, result); | |
760 | } | |
761 | ||
762 | /* Verify that the given call to get_visual_column fails gracefully. */ | |
763 | ||
1bdd665a DM |
764 | #define ASSERT_GET_VISUAL_COLUMN_FAILS(FILE_CACHE, \ |
765 | FILENAME, LINE, COLUMN, \ | |
10fcc142 DM |
766 | TAB_WIDTH) \ |
767 | SELFTEST_BEGIN_STMT \ | |
768 | assert_get_visual_column_fails (SELFTEST_LOCATION, \ | |
1bdd665a | 769 | FILE_CACHE, \ |
10fcc142 DM |
770 | FILENAME, LINE, COLUMN, \ |
771 | TAB_WIDTH); \ | |
772 | SELFTEST_END_STMT | |
773 | ||
774 | /* Verify that get_visual_column works as expected. */ | |
775 | ||
776 | static void | |
777 | test_get_visual_column () | |
778 | { | |
779 | /* Create a tempfile with a mixture of tabs and spaces. | |
780 | ||
781 | Both lines have either a space or a tab, then " line N", | |
782 | for 8 characters in total. | |
783 | ||
784 | 1-based "columns" (w.r.t. to line 1): | |
785 | .....................0000000001111. | |
786 | .....................1234567890123. */ | |
787 | const char *content = (" line 1\n" | |
788 | "\t line 2\n"); | |
789 | line_table_test ltt; | |
790 | temp_source_file tmp (SELFTEST_LOCATION, ".txt", content); | |
1bdd665a | 791 | file_cache fc; |
10fcc142 DM |
792 | |
793 | const unsigned int tab_width = 8; | |
794 | const char *file = tmp.get_filename (); | |
795 | ||
796 | /* Line 1 (space-based indentation). */ | |
797 | { | |
798 | const int line = 1; | |
1bdd665a DM |
799 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 1, tab_width, 0, 0); |
800 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 2, tab_width, 1, 1); | |
801 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 3, tab_width, 2, 2); | |
10fcc142 | 802 | /* first_nws should have stopped increasing. */ |
1bdd665a | 803 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 4, tab_width, 3, 2); |
10fcc142 | 804 | /* Verify the end-of-line boundary. */ |
1bdd665a DM |
805 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 8, tab_width, 7, 2); |
806 | ASSERT_GET_VISUAL_COLUMN_FAILS (fc, file, line, 9, tab_width); | |
10fcc142 DM |
807 | } |
808 | ||
809 | /* Line 2 (tab-based indentation). */ | |
810 | { | |
811 | const int line = 2; | |
1bdd665a DM |
812 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 1, tab_width, 0, 0); |
813 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 2, tab_width, 8, 8); | |
814 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 3, tab_width, 9, 9); | |
10fcc142 | 815 | /* first_nws should have stopped increasing. */ |
1bdd665a | 816 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 4, tab_width, 10, 9); |
10fcc142 | 817 | /* Verify the end-of-line boundary. */ |
1bdd665a DM |
818 | ASSERT_GET_VISUAL_COLUMN_SUCCEEDS (fc, file, line, 8, tab_width, 14, 9); |
819 | ASSERT_GET_VISUAL_COLUMN_FAILS (fc, file, line, 9, tab_width); | |
10fcc142 DM |
820 | } |
821 | } | |
822 | ||
823 | /* Run all of the selftests within this file. */ | |
824 | ||
825 | void | |
d5148d4f | 826 | c_indentation_cc_tests () |
10fcc142 DM |
827 | { |
828 | test_next_tab_stop (); | |
829 | test_get_visual_column (); | |
830 | } | |
831 | ||
832 | } // namespace selftest | |
833 | ||
834 | #endif /* CHECKING_P */ |