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038b5cc0 | 1 | /* Diagnostic routines shared by all languages that are variants of C. |
85ec4feb | 2 | Copyright (C) 1992-2018 Free Software Foundation, Inc. |
038b5cc0 MP |
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 "target.h" | |
24 | #include "function.h" | |
25 | #include "tree.h" | |
26 | #include "c-common.h" | |
4d0cdd0c | 27 | #include "memmodel.h" |
038b5cc0 MP |
28 | #include "tm_p.h" |
29 | #include "diagnostic.h" | |
30 | #include "intl.h" | |
314e6352 ML |
31 | #include "stringpool.h" |
32 | #include "attribs.h" | |
6dc4a604 | 33 | #include "asan.h" |
975672f3 | 34 | #include "gcc-rich-location.h" |
684f84de | 35 | #include "gimplify.h" |
3e2becc4 | 36 | #include "c-family/c-indentation.h" |
4252ccd7 | 37 | #include "calls.h" |
038b5cc0 MP |
38 | |
39 | /* Print a warning if a constant expression had overflow in folding. | |
40 | Invoke this function on every expression that the language | |
41 | requires to be a constant expression. | |
42 | Note the ANSI C standard says it is erroneous for a | |
43 | constant expression to overflow. */ | |
44 | ||
45 | void | |
46 | constant_expression_warning (tree value) | |
47 | { | |
48 | if (warn_overflow && pedantic | |
49 | && (TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST | |
50 | || TREE_CODE (value) == FIXED_CST | |
51 | || TREE_CODE (value) == VECTOR_CST | |
52 | || TREE_CODE (value) == COMPLEX_CST) | |
53 | && TREE_OVERFLOW (value)) | |
54 | pedwarn (input_location, OPT_Woverflow, "overflow in constant expression"); | |
55 | } | |
56 | ||
57 | /* The same as above but print an unconditional error. */ | |
58 | ||
59 | void | |
60 | constant_expression_error (tree value) | |
61 | { | |
62 | if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST | |
63 | || TREE_CODE (value) == FIXED_CST | |
64 | || TREE_CODE (value) == VECTOR_CST | |
65 | || TREE_CODE (value) == COMPLEX_CST) | |
66 | && TREE_OVERFLOW (value)) | |
67 | error ("overflow in constant expression"); | |
68 | } | |
69 | ||
3cd211af MS |
70 | /* Print a warning if an expression result VALUE had an overflow |
71 | in folding and its operands hadn't. EXPR, which may be null, is | |
72 | the operand of the expression. | |
038b5cc0 MP |
73 | |
74 | Invoke this function on every expression that | |
75 | (1) appears in the source code, and | |
76 | (2) is a constant expression that overflowed, and | |
77 | (3) is not already checked by convert_and_check; | |
78 | however, do not invoke this function on operands of explicit casts | |
79 | or when the expression is the result of an operator and any operand | |
80 | already overflowed. */ | |
81 | ||
82 | void | |
3cd211af | 83 | overflow_warning (location_t loc, tree value, tree expr) |
038b5cc0 MP |
84 | { |
85 | if (c_inhibit_evaluation_warnings != 0) | |
86 | return; | |
87 | ||
3cd211af MS |
88 | const char *warnfmt = NULL; |
89 | ||
038b5cc0 MP |
90 | switch (TREE_CODE (value)) |
91 | { | |
92 | case INTEGER_CST: | |
3cd211af MS |
93 | warnfmt = (expr |
94 | ? G_("integer overflow in expression %qE of type %qT " | |
95 | "results in %qE") | |
96 | : G_("integer overflow in expression of type %qT " | |
97 | "results in %qE")); | |
038b5cc0 MP |
98 | break; |
99 | ||
100 | case REAL_CST: | |
3cd211af | 101 | warnfmt = (expr |
40659769 ML |
102 | ? G_("floating point overflow in expression %qE " |
103 | "of type %qT results in %qE") | |
104 | : G_("floating point overflow in expression of type %qT " | |
105 | "results in %qE")); | |
038b5cc0 MP |
106 | break; |
107 | ||
108 | case FIXED_CST: | |
3cd211af MS |
109 | warnfmt = (expr |
110 | ? G_("fixed-point overflow in expression %qE of type %qT " | |
111 | "results in %qE") | |
112 | : G_("fixed-point overflow in expression of type %qT " | |
113 | "results in %qE")); | |
038b5cc0 MP |
114 | break; |
115 | ||
116 | case VECTOR_CST: | |
3cd211af MS |
117 | warnfmt = (expr |
118 | ? G_("vector overflow in expression %qE of type %qT " | |
119 | "results in %qE") | |
120 | : G_("vector overflow in expression of type %qT " | |
121 | "results in %qE")); | |
038b5cc0 MP |
122 | break; |
123 | ||
124 | case COMPLEX_CST: | |
125 | if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST) | |
3cd211af MS |
126 | warnfmt = (expr |
127 | ? G_("complex integer overflow in expression %qE " | |
128 | "of type %qT results in %qE") | |
129 | : G_("complex integer overflow in expression of type %qT " | |
130 | "results in %qE")); | |
038b5cc0 | 131 | else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST) |
3cd211af MS |
132 | warnfmt = (expr |
133 | ? G_("complex floating point overflow in expression %qE " | |
134 | "of type %qT results in %qE") | |
135 | : G_("complex floating point overflow in expression " | |
136 | "of type %qT results in %qE")); | |
137 | else | |
138 | return; | |
038b5cc0 MP |
139 | break; |
140 | ||
141 | default: | |
3cd211af | 142 | return; |
038b5cc0 | 143 | } |
3cd211af MS |
144 | |
145 | if (expr) | |
146 | warning_at (loc, OPT_Woverflow, warnfmt, expr, TREE_TYPE (expr), value); | |
147 | else | |
148 | warning_at (loc, OPT_Woverflow, warnfmt, TREE_TYPE (value), value); | |
149 | ||
150 | TREE_NO_WARNING (value) = 1; | |
038b5cc0 MP |
151 | } |
152 | ||
684f84de MP |
153 | /* Helper function for walk_tree. Unwrap C_MAYBE_CONST_EXPRs in an expression |
154 | pointed to by TP. */ | |
155 | ||
156 | static tree | |
157 | unwrap_c_maybe_const (tree *tp, int *walk_subtrees, void *) | |
158 | { | |
159 | if (TREE_CODE (*tp) == C_MAYBE_CONST_EXPR) | |
160 | { | |
161 | *tp = C_MAYBE_CONST_EXPR_EXPR (*tp); | |
162 | /* C_MAYBE_CONST_EXPRs don't nest. */ | |
163 | *walk_subtrees = false; | |
164 | } | |
165 | return NULL_TREE; | |
166 | } | |
167 | ||
038b5cc0 MP |
168 | /* Warn about uses of logical || / && operator in a context where it |
169 | is likely that the bitwise equivalent was intended by the | |
170 | programmer. We have seen an expression in which CODE is a binary | |
171 | operator used to combine expressions OP_LEFT and OP_RIGHT, which before folding | |
172 | had CODE_LEFT and CODE_RIGHT, into an expression of type TYPE. */ | |
173 | ||
174 | void | |
175 | warn_logical_operator (location_t location, enum tree_code code, tree type, | |
176 | enum tree_code code_left, tree op_left, | |
177 | enum tree_code ARG_UNUSED (code_right), tree op_right) | |
178 | { | |
179 | int or_op = (code == TRUTH_ORIF_EXPR || code == TRUTH_OR_EXPR); | |
180 | int in0_p, in1_p, in_p; | |
181 | tree low0, low1, low, high0, high1, high, lhs, rhs, tem; | |
182 | bool strict_overflow_p = false; | |
183 | ||
82cfbd01 MP |
184 | if (!warn_logical_op) |
185 | return; | |
186 | ||
038b5cc0 MP |
187 | if (code != TRUTH_ANDIF_EXPR |
188 | && code != TRUTH_AND_EXPR | |
189 | && code != TRUTH_ORIF_EXPR | |
190 | && code != TRUTH_OR_EXPR) | |
191 | return; | |
192 | ||
193 | /* We don't want to warn if either operand comes from a macro | |
194 | expansion. ??? This doesn't work with e.g. NEGATE_EXPR yet; | |
195 | see PR61534. */ | |
196 | if (from_macro_expansion_at (EXPR_LOCATION (op_left)) | |
197 | || from_macro_expansion_at (EXPR_LOCATION (op_right))) | |
198 | return; | |
199 | ||
200 | /* Warn if &&/|| are being used in a context where it is | |
201 | likely that the bitwise equivalent was intended by the | |
202 | programmer. That is, an expression such as op && MASK | |
203 | where op should not be any boolean expression, nor a | |
204 | constant, and mask seems to be a non-boolean integer constant. */ | |
205 | if (TREE_CODE (op_right) == CONST_DECL) | |
206 | /* An enumerator counts as a constant. */ | |
207 | op_right = DECL_INITIAL (op_right); | |
208 | if (!truth_value_p (code_left) | |
209 | && INTEGRAL_TYPE_P (TREE_TYPE (op_left)) | |
210 | && !CONSTANT_CLASS_P (op_left) | |
211 | && !TREE_NO_WARNING (op_left) | |
212 | && TREE_CODE (op_right) == INTEGER_CST | |
213 | && !integer_zerop (op_right) | |
214 | && !integer_onep (op_right)) | |
215 | { | |
216 | if (or_op) | |
217 | warning_at (location, OPT_Wlogical_op, "logical %<or%>" | |
218 | " applied to non-boolean constant"); | |
219 | else | |
220 | warning_at (location, OPT_Wlogical_op, "logical %<and%>" | |
221 | " applied to non-boolean constant"); | |
222 | TREE_NO_WARNING (op_left) = true; | |
223 | return; | |
224 | } | |
225 | ||
226 | /* We do not warn for constants because they are typical of macro | |
227 | expansions that test for features. */ | |
228 | if (CONSTANT_CLASS_P (fold_for_warn (op_left)) | |
229 | || CONSTANT_CLASS_P (fold_for_warn (op_right))) | |
230 | return; | |
231 | ||
232 | /* This warning only makes sense with logical operands. */ | |
233 | if (!(truth_value_p (TREE_CODE (op_left)) | |
234 | || INTEGRAL_TYPE_P (TREE_TYPE (op_left))) | |
235 | || !(truth_value_p (TREE_CODE (op_right)) | |
236 | || INTEGRAL_TYPE_P (TREE_TYPE (op_right)))) | |
237 | return; | |
238 | ||
239 | /* The range computations only work with scalars. */ | |
240 | if (VECTOR_TYPE_P (TREE_TYPE (op_left)) | |
241 | || VECTOR_TYPE_P (TREE_TYPE (op_right))) | |
242 | return; | |
243 | ||
244 | /* We first test whether either side separately is trivially true | |
245 | (with OR) or trivially false (with AND). If so, do not warn. | |
246 | This is a common idiom for testing ranges of data types in | |
247 | portable code. */ | |
684f84de MP |
248 | op_left = unshare_expr (op_left); |
249 | walk_tree_without_duplicates (&op_left, unwrap_c_maybe_const, NULL); | |
038b5cc0 MP |
250 | lhs = make_range (op_left, &in0_p, &low0, &high0, &strict_overflow_p); |
251 | if (!lhs) | |
252 | return; | |
038b5cc0 MP |
253 | |
254 | /* If this is an OR operation, invert both sides; now, the result | |
255 | should be always false to get a warning. */ | |
256 | if (or_op) | |
257 | in0_p = !in0_p; | |
258 | ||
259 | tem = build_range_check (UNKNOWN_LOCATION, type, lhs, in0_p, low0, high0); | |
260 | if (tem && integer_zerop (tem)) | |
261 | return; | |
262 | ||
684f84de MP |
263 | op_right = unshare_expr (op_right); |
264 | walk_tree_without_duplicates (&op_right, unwrap_c_maybe_const, NULL); | |
038b5cc0 MP |
265 | rhs = make_range (op_right, &in1_p, &low1, &high1, &strict_overflow_p); |
266 | if (!rhs) | |
267 | return; | |
038b5cc0 MP |
268 | |
269 | /* If this is an OR operation, invert both sides; now, the result | |
270 | should be always false to get a warning. */ | |
271 | if (or_op) | |
272 | in1_p = !in1_p; | |
273 | ||
274 | tem = build_range_check (UNKNOWN_LOCATION, type, rhs, in1_p, low1, high1); | |
275 | if (tem && integer_zerop (tem)) | |
276 | return; | |
277 | ||
278 | /* If both expressions have the same operand, if we can merge the | |
279 | ranges, ... */ | |
280 | if (operand_equal_p (lhs, rhs, 0) | |
281 | && merge_ranges (&in_p, &low, &high, in0_p, low0, high0, | |
282 | in1_p, low1, high1)) | |
283 | { | |
284 | tem = build_range_check (UNKNOWN_LOCATION, type, lhs, in_p, low, high); | |
285 | /* ... and if the range test is always false, then warn. */ | |
286 | if (tem && integer_zerop (tem)) | |
287 | { | |
288 | if (or_op) | |
289 | warning_at (location, OPT_Wlogical_op, | |
290 | "logical %<or%> of collectively exhaustive tests is " | |
291 | "always true"); | |
292 | else | |
293 | warning_at (location, OPT_Wlogical_op, | |
294 | "logical %<and%> of mutually exclusive tests is " | |
295 | "always false"); | |
296 | } | |
297 | /* Or warn if the operands have exactly the same range, e.g. | |
298 | A > 0 && A > 0. */ | |
299 | else if (tree_int_cst_equal (low0, low1) | |
300 | && tree_int_cst_equal (high0, high1)) | |
301 | { | |
302 | if (or_op) | |
303 | warning_at (location, OPT_Wlogical_op, | |
304 | "logical %<or%> of equal expressions"); | |
305 | else | |
306 | warning_at (location, OPT_Wlogical_op, | |
307 | "logical %<and%> of equal expressions"); | |
308 | } | |
309 | } | |
310 | } | |
311 | ||
312 | /* Helper function for warn_tautological_cmp. Look for ARRAY_REFs | |
313 | with constant indices. */ | |
314 | ||
315 | static tree | |
8fa18c06 | 316 | find_array_ref_with_const_idx_r (tree *expr_p, int *, void *) |
038b5cc0 MP |
317 | { |
318 | tree expr = *expr_p; | |
319 | ||
320 | if ((TREE_CODE (expr) == ARRAY_REF | |
321 | || TREE_CODE (expr) == ARRAY_RANGE_REF) | |
322 | && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST) | |
8fa18c06 | 323 | return integer_type_node; |
038b5cc0 MP |
324 | |
325 | return NULL_TREE; | |
326 | } | |
327 | ||
bc7fe952 MP |
328 | /* Subroutine of warn_tautological_cmp. Warn about bitwise comparison |
329 | that always evaluate to true or false. LOC is the location of the | |
330 | ==/!= comparison specified by CODE; LHS and RHS are the usual operands | |
331 | of this comparison. */ | |
332 | ||
333 | static void | |
334 | warn_tautological_bitwise_comparison (location_t loc, tree_code code, | |
335 | tree lhs, tree rhs) | |
336 | { | |
337 | if (code != EQ_EXPR && code != NE_EXPR) | |
338 | return; | |
339 | ||
340 | /* Extract the operands from e.g. (x & 8) == 4. */ | |
341 | tree bitop; | |
342 | tree cst; | |
343 | if ((TREE_CODE (lhs) == BIT_AND_EXPR | |
344 | || TREE_CODE (lhs) == BIT_IOR_EXPR) | |
345 | && TREE_CODE (rhs) == INTEGER_CST) | |
346 | bitop = lhs, cst = rhs; | |
347 | else if ((TREE_CODE (rhs) == BIT_AND_EXPR | |
348 | || TREE_CODE (rhs) == BIT_IOR_EXPR) | |
349 | && TREE_CODE (lhs) == INTEGER_CST) | |
350 | bitop = rhs, cst = lhs; | |
351 | else | |
352 | return; | |
353 | ||
354 | tree bitopcst; | |
355 | if (TREE_CODE (TREE_OPERAND (bitop, 0)) == INTEGER_CST) | |
356 | bitopcst = TREE_OPERAND (bitop, 0); | |
357 | else if (TREE_CODE (TREE_OPERAND (bitop, 1)) == INTEGER_CST) | |
358 | bitopcst = TREE_OPERAND (bitop, 1); | |
359 | else | |
360 | return; | |
361 | ||
a1488398 | 362 | /* Note that the two operands are from before the usual integer |
4e34b338 JJ |
363 | conversions, so their types might not be the same. |
364 | Use the larger of the two precisions and ignore bits outside | |
365 | of that. */ | |
366 | int prec = MAX (TYPE_PRECISION (TREE_TYPE (cst)), | |
367 | TYPE_PRECISION (TREE_TYPE (bitopcst))); | |
368 | ||
802b38c9 JJ |
369 | wide_int bitopcstw = wi::to_wide (bitopcst, prec); |
370 | wide_int cstw = wi::to_wide (cst, prec); | |
4e34b338 JJ |
371 | |
372 | wide_int res; | |
bc7fe952 | 373 | if (TREE_CODE (bitop) == BIT_AND_EXPR) |
4e34b338 | 374 | res = bitopcstw & cstw; |
bc7fe952 | 375 | else |
4e34b338 | 376 | res = bitopcstw | cstw; |
bc7fe952 MP |
377 | |
378 | /* For BIT_AND only warn if (CST2 & CST1) != CST1, and | |
379 | for BIT_OR only if (CST2 | CST1) != CST1. */ | |
4e34b338 | 380 | if (res == cstw) |
bc7fe952 MP |
381 | return; |
382 | ||
383 | if (code == EQ_EXPR) | |
384 | warning_at (loc, OPT_Wtautological_compare, | |
385 | "bitwise comparison always evaluates to false"); | |
386 | else | |
387 | warning_at (loc, OPT_Wtautological_compare, | |
388 | "bitwise comparison always evaluates to true"); | |
389 | } | |
390 | ||
038b5cc0 MP |
391 | /* Warn if a self-comparison always evaluates to true or false. LOC |
392 | is the location of the comparison with code CODE, LHS and RHS are | |
393 | operands of the comparison. */ | |
394 | ||
395 | void | |
396 | warn_tautological_cmp (location_t loc, enum tree_code code, tree lhs, tree rhs) | |
397 | { | |
398 | if (TREE_CODE_CLASS (code) != tcc_comparison) | |
399 | return; | |
400 | ||
401 | /* Don't warn for various macro expansions. */ | |
402 | if (from_macro_expansion_at (loc) | |
403 | || from_macro_expansion_at (EXPR_LOCATION (lhs)) | |
404 | || from_macro_expansion_at (EXPR_LOCATION (rhs))) | |
405 | return; | |
406 | ||
bc7fe952 MP |
407 | warn_tautological_bitwise_comparison (loc, code, lhs, rhs); |
408 | ||
038b5cc0 MP |
409 | /* We do not warn for constants because they are typical of macro |
410 | expansions that test for features, sizeof, and similar. */ | |
411 | if (CONSTANT_CLASS_P (fold_for_warn (lhs)) | |
412 | || CONSTANT_CLASS_P (fold_for_warn (rhs))) | |
413 | return; | |
414 | ||
415 | /* Don't warn for e.g. | |
416 | HOST_WIDE_INT n; | |
417 | ... | |
418 | if (n == (long) n) ... | |
419 | */ | |
420 | if ((CONVERT_EXPR_P (lhs) || TREE_CODE (lhs) == NON_LVALUE_EXPR) | |
421 | || (CONVERT_EXPR_P (rhs) || TREE_CODE (rhs) == NON_LVALUE_EXPR)) | |
422 | return; | |
423 | ||
424 | /* Don't warn if either LHS or RHS has an IEEE floating-point type. | |
425 | It could be a NaN, and NaN never compares equal to anything, even | |
426 | itself. */ | |
427 | if (FLOAT_TYPE_P (TREE_TYPE (lhs)) || FLOAT_TYPE_P (TREE_TYPE (rhs))) | |
428 | return; | |
429 | ||
430 | if (operand_equal_p (lhs, rhs, 0)) | |
431 | { | |
432 | /* Don't warn about array references with constant indices; | |
433 | these are likely to come from a macro. */ | |
8fa18c06 MP |
434 | if (walk_tree_without_duplicates (&lhs, find_array_ref_with_const_idx_r, |
435 | NULL)) | |
038b5cc0 MP |
436 | return; |
437 | const bool always_true = (code == EQ_EXPR || code == LE_EXPR | |
438 | || code == GE_EXPR || code == UNLE_EXPR | |
439 | || code == UNGE_EXPR || code == UNEQ_EXPR); | |
440 | if (always_true) | |
441 | warning_at (loc, OPT_Wtautological_compare, | |
442 | "self-comparison always evaluates to true"); | |
443 | else | |
444 | warning_at (loc, OPT_Wtautological_compare, | |
445 | "self-comparison always evaluates to false"); | |
446 | } | |
447 | } | |
448 | ||
449 | /* Return true iff EXPR only contains boolean operands, or comparisons. */ | |
450 | ||
451 | static bool | |
452 | expr_has_boolean_operands_p (tree expr) | |
453 | { | |
454 | STRIP_NOPS (expr); | |
455 | ||
456 | if (CONVERT_EXPR_P (expr)) | |
457 | return bool_promoted_to_int_p (expr); | |
458 | else if (UNARY_CLASS_P (expr)) | |
459 | return expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)); | |
460 | else if (BINARY_CLASS_P (expr)) | |
461 | return (expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)) | |
462 | && expr_has_boolean_operands_p (TREE_OPERAND (expr, 1))); | |
463 | else if (COMPARISON_CLASS_P (expr)) | |
464 | return true; | |
465 | else | |
466 | return false; | |
467 | } | |
468 | ||
469 | /* Warn about logical not used on the left hand side operand of a comparison. | |
470 | This function assumes that the LHS is inside of TRUTH_NOT_EXPR. | |
471 | Do not warn if RHS is of a boolean type, a logical operator, or | |
472 | a comparison. */ | |
473 | ||
474 | void | |
475 | warn_logical_not_parentheses (location_t location, enum tree_code code, | |
476 | tree lhs, tree rhs) | |
477 | { | |
478 | if (TREE_CODE_CLASS (code) != tcc_comparison | |
479 | || TREE_TYPE (rhs) == NULL_TREE | |
480 | || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE | |
481 | || truth_value_p (TREE_CODE (rhs))) | |
482 | return; | |
483 | ||
484 | /* Don't warn for expression like !x == ~(bool1 | bool2). */ | |
485 | if (expr_has_boolean_operands_p (rhs)) | |
486 | return; | |
487 | ||
488 | /* Don't warn for !x == 0 or !y != 0, those are equivalent to | |
489 | !(x == 0) or !(y != 0). */ | |
490 | if ((code == EQ_EXPR || code == NE_EXPR) | |
491 | && integer_zerop (rhs)) | |
492 | return; | |
493 | ||
494 | if (warning_at (location, OPT_Wlogical_not_parentheses, | |
495 | "logical not is only applied to the left hand side of " | |
496 | "comparison") | |
497 | && EXPR_HAS_LOCATION (lhs)) | |
498 | { | |
499 | location_t lhs_loc = EXPR_LOCATION (lhs); | |
500 | rich_location richloc (line_table, lhs_loc); | |
501 | richloc.add_fixit_insert_before (lhs_loc, "("); | |
502 | richloc.add_fixit_insert_after (lhs_loc, ")"); | |
64a5912c DM |
503 | inform (&richloc, "add parentheses around left hand side " |
504 | "expression to silence this warning"); | |
038b5cc0 MP |
505 | } |
506 | } | |
507 | ||
508 | /* Warn if EXP contains any computations whose results are not used. | |
509 | Return true if a warning is printed; false otherwise. LOCUS is the | |
510 | (potential) location of the expression. */ | |
511 | ||
512 | bool | |
513 | warn_if_unused_value (const_tree exp, location_t locus) | |
514 | { | |
515 | restart: | |
516 | if (TREE_USED (exp) || TREE_NO_WARNING (exp)) | |
517 | return false; | |
518 | ||
519 | /* Don't warn about void constructs. This includes casting to void, | |
520 | void function calls, and statement expressions with a final cast | |
521 | to void. */ | |
522 | if (VOID_TYPE_P (TREE_TYPE (exp))) | |
523 | return false; | |
524 | ||
525 | if (EXPR_HAS_LOCATION (exp)) | |
526 | locus = EXPR_LOCATION (exp); | |
527 | ||
528 | switch (TREE_CODE (exp)) | |
529 | { | |
530 | case PREINCREMENT_EXPR: | |
531 | case POSTINCREMENT_EXPR: | |
532 | case PREDECREMENT_EXPR: | |
533 | case POSTDECREMENT_EXPR: | |
534 | case MODIFY_EXPR: | |
535 | case INIT_EXPR: | |
536 | case TARGET_EXPR: | |
537 | case CALL_EXPR: | |
538 | case TRY_CATCH_EXPR: | |
038b5cc0 MP |
539 | case EXIT_EXPR: |
540 | case VA_ARG_EXPR: | |
541 | return false; | |
542 | ||
543 | case BIND_EXPR: | |
544 | /* For a binding, warn if no side effect within it. */ | |
545 | exp = BIND_EXPR_BODY (exp); | |
546 | goto restart; | |
547 | ||
548 | case SAVE_EXPR: | |
549 | case NON_LVALUE_EXPR: | |
550 | case NOP_EXPR: | |
551 | exp = TREE_OPERAND (exp, 0); | |
552 | goto restart; | |
553 | ||
554 | case TRUTH_ORIF_EXPR: | |
555 | case TRUTH_ANDIF_EXPR: | |
556 | /* In && or ||, warn if 2nd operand has no side effect. */ | |
557 | exp = TREE_OPERAND (exp, 1); | |
558 | goto restart; | |
559 | ||
560 | case COMPOUND_EXPR: | |
561 | if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus)) | |
562 | return true; | |
563 | /* Let people do `(foo (), 0)' without a warning. */ | |
564 | if (TREE_CONSTANT (TREE_OPERAND (exp, 1))) | |
565 | return false; | |
566 | exp = TREE_OPERAND (exp, 1); | |
567 | goto restart; | |
568 | ||
569 | case COND_EXPR: | |
570 | /* If this is an expression with side effects, don't warn; this | |
571 | case commonly appears in macro expansions. */ | |
572 | if (TREE_SIDE_EFFECTS (exp)) | |
573 | return false; | |
574 | goto warn; | |
575 | ||
576 | case INDIRECT_REF: | |
577 | /* Don't warn about automatic dereferencing of references, since | |
578 | the user cannot control it. */ | |
579 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE) | |
580 | { | |
581 | exp = TREE_OPERAND (exp, 0); | |
582 | goto restart; | |
583 | } | |
584 | /* Fall through. */ | |
585 | ||
586 | default: | |
587 | /* Referencing a volatile value is a side effect, so don't warn. */ | |
588 | if ((DECL_P (exp) || REFERENCE_CLASS_P (exp)) | |
589 | && TREE_THIS_VOLATILE (exp)) | |
590 | return false; | |
591 | ||
592 | /* If this is an expression which has no operands, there is no value | |
593 | to be unused. There are no such language-independent codes, | |
594 | but front ends may define such. */ | |
595 | if (EXPRESSION_CLASS_P (exp) && TREE_OPERAND_LENGTH (exp) == 0) | |
596 | return false; | |
597 | ||
598 | warn: | |
599 | return warning_at (locus, OPT_Wunused_value, "value computed is not used"); | |
600 | } | |
601 | } | |
602 | ||
0444aa9c NS |
603 | /* Print a warning about casts that might indicate violation of strict |
604 | aliasing rules if -Wstrict-aliasing is used and strict aliasing | |
605 | mode is in effect. LOC is the location of the expression being | |
606 | cast, EXPR might be from inside it. TYPE is the type we're casting | |
607 | to. */ | |
038b5cc0 MP |
608 | |
609 | bool | |
0444aa9c | 610 | strict_aliasing_warning (location_t loc, tree type, tree expr) |
038b5cc0 | 611 | { |
0444aa9c NS |
612 | if (loc == UNKNOWN_LOCATION) |
613 | loc = input_location; | |
614 | ||
038b5cc0 MP |
615 | /* Strip pointer conversion chains and get to the correct original type. */ |
616 | STRIP_NOPS (expr); | |
0444aa9c | 617 | tree otype = TREE_TYPE (expr); |
038b5cc0 MP |
618 | |
619 | if (!(flag_strict_aliasing | |
620 | && POINTER_TYPE_P (type) | |
621 | && POINTER_TYPE_P (otype) | |
622 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
623 | /* If the type we are casting to is a ref-all pointer | |
624 | dereferencing it is always valid. */ | |
625 | || TYPE_REF_CAN_ALIAS_ALL (type)) | |
626 | return false; | |
627 | ||
628 | if ((warn_strict_aliasing > 1) && TREE_CODE (expr) == ADDR_EXPR | |
629 | && (DECL_P (TREE_OPERAND (expr, 0)) | |
630 | || handled_component_p (TREE_OPERAND (expr, 0)))) | |
631 | { | |
632 | /* Casting the address of an object to non void pointer. Warn | |
633 | if the cast breaks type based aliasing. */ | |
634 | if (!COMPLETE_TYPE_P (TREE_TYPE (type)) && warn_strict_aliasing == 2) | |
635 | { | |
0444aa9c NS |
636 | warning_at (loc, OPT_Wstrict_aliasing, |
637 | "type-punning to incomplete type " | |
638 | "might break strict-aliasing rules"); | |
038b5cc0 MP |
639 | return true; |
640 | } | |
641 | else | |
642 | { | |
643 | /* warn_strict_aliasing >= 3. This includes the default (3). | |
644 | Only warn if the cast is dereferenced immediately. */ | |
645 | alias_set_type set1 | |
646 | = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0))); | |
647 | alias_set_type set2 = get_alias_set (TREE_TYPE (type)); | |
648 | ||
39aac208 RB |
649 | if (set2 != 0 |
650 | && set1 != set2 | |
651 | && !alias_set_subset_of (set2, set1) | |
652 | && !alias_sets_conflict_p (set1, set2)) | |
038b5cc0 | 653 | { |
0444aa9c NS |
654 | warning_at (loc, OPT_Wstrict_aliasing, |
655 | "dereferencing type-punned " | |
656 | "pointer will break strict-aliasing rules"); | |
038b5cc0 MP |
657 | return true; |
658 | } | |
659 | else if (warn_strict_aliasing == 2 | |
660 | && !alias_sets_must_conflict_p (set1, set2)) | |
661 | { | |
0444aa9c NS |
662 | warning_at (loc, OPT_Wstrict_aliasing, |
663 | "dereferencing type-punned " | |
664 | "pointer might break strict-aliasing rules"); | |
038b5cc0 MP |
665 | return true; |
666 | } | |
667 | } | |
668 | } | |
669 | else if ((warn_strict_aliasing == 1) && !VOID_TYPE_P (TREE_TYPE (otype))) | |
670 | { | |
671 | /* At this level, warn for any conversions, even if an address is | |
672 | not taken in the same statement. This will likely produce many | |
673 | false positives, but could be useful to pinpoint problems that | |
674 | are not revealed at higher levels. */ | |
675 | alias_set_type set1 = get_alias_set (TREE_TYPE (otype)); | |
676 | alias_set_type set2 = get_alias_set (TREE_TYPE (type)); | |
677 | if (!COMPLETE_TYPE_P (type) | |
678 | || !alias_sets_must_conflict_p (set1, set2)) | |
679 | { | |
0444aa9c NS |
680 | warning_at (loc, OPT_Wstrict_aliasing, |
681 | "dereferencing type-punned " | |
682 | "pointer might break strict-aliasing rules"); | |
038b5cc0 MP |
683 | return true; |
684 | } | |
685 | } | |
686 | ||
687 | return false; | |
688 | } | |
689 | ||
690 | /* Warn about memset (&a, 0, sizeof (&a)); and similar mistakes with | |
691 | sizeof as last operand of certain builtins. */ | |
692 | ||
693 | void | |
694 | sizeof_pointer_memaccess_warning (location_t *sizeof_arg_loc, tree callee, | |
695 | vec<tree, va_gc> *params, tree *sizeof_arg, | |
696 | bool (*comp_types) (tree, tree)) | |
697 | { | |
698 | tree type, dest = NULL_TREE, src = NULL_TREE, tem; | |
699 | bool strop = false, cmp = false; | |
700 | unsigned int idx = ~0; | |
701 | location_t loc; | |
702 | ||
703 | if (TREE_CODE (callee) != FUNCTION_DECL | |
704 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
705 | || vec_safe_length (params) <= 1) | |
706 | return; | |
707 | ||
025d57f0 MS |
708 | enum built_in_function fncode = DECL_FUNCTION_CODE (callee); |
709 | switch (fncode) | |
038b5cc0 MP |
710 | { |
711 | case BUILT_IN_STRNCMP: | |
712 | case BUILT_IN_STRNCASECMP: | |
713 | cmp = true; | |
714 | /* FALLTHRU */ | |
715 | case BUILT_IN_STRNCPY: | |
716 | case BUILT_IN_STRNCPY_CHK: | |
717 | case BUILT_IN_STRNCAT: | |
718 | case BUILT_IN_STRNCAT_CHK: | |
719 | case BUILT_IN_STPNCPY: | |
720 | case BUILT_IN_STPNCPY_CHK: | |
721 | strop = true; | |
722 | /* FALLTHRU */ | |
723 | case BUILT_IN_MEMCPY: | |
724 | case BUILT_IN_MEMCPY_CHK: | |
725 | case BUILT_IN_MEMMOVE: | |
726 | case BUILT_IN_MEMMOVE_CHK: | |
727 | if (params->length () < 3) | |
728 | return; | |
729 | src = (*params)[1]; | |
730 | dest = (*params)[0]; | |
731 | idx = 2; | |
732 | break; | |
733 | case BUILT_IN_BCOPY: | |
734 | if (params->length () < 3) | |
735 | return; | |
736 | src = (*params)[0]; | |
737 | dest = (*params)[1]; | |
738 | idx = 2; | |
739 | break; | |
740 | case BUILT_IN_MEMCMP: | |
741 | case BUILT_IN_BCMP: | |
742 | if (params->length () < 3) | |
743 | return; | |
744 | src = (*params)[1]; | |
745 | dest = (*params)[0]; | |
746 | idx = 2; | |
747 | cmp = true; | |
748 | break; | |
749 | case BUILT_IN_MEMSET: | |
750 | case BUILT_IN_MEMSET_CHK: | |
751 | if (params->length () < 3) | |
752 | return; | |
753 | dest = (*params)[0]; | |
754 | idx = 2; | |
755 | break; | |
756 | case BUILT_IN_BZERO: | |
757 | dest = (*params)[0]; | |
758 | idx = 1; | |
759 | break; | |
760 | case BUILT_IN_STRNDUP: | |
761 | src = (*params)[0]; | |
762 | strop = true; | |
763 | idx = 1; | |
764 | break; | |
765 | case BUILT_IN_MEMCHR: | |
766 | if (params->length () < 3) | |
767 | return; | |
768 | src = (*params)[0]; | |
769 | idx = 2; | |
770 | break; | |
771 | case BUILT_IN_SNPRINTF: | |
772 | case BUILT_IN_SNPRINTF_CHK: | |
773 | case BUILT_IN_VSNPRINTF: | |
774 | case BUILT_IN_VSNPRINTF_CHK: | |
775 | dest = (*params)[0]; | |
776 | idx = 1; | |
777 | strop = true; | |
778 | break; | |
779 | default: | |
780 | break; | |
781 | } | |
782 | ||
783 | if (idx >= 3) | |
784 | return; | |
785 | ||
786 | if (sizeof_arg[idx] == NULL || sizeof_arg[idx] == error_mark_node) | |
787 | return; | |
788 | ||
789 | type = TYPE_P (sizeof_arg[idx]) | |
790 | ? sizeof_arg[idx] : TREE_TYPE (sizeof_arg[idx]); | |
025d57f0 | 791 | |
038b5cc0 | 792 | if (!POINTER_TYPE_P (type)) |
025d57f0 MS |
793 | { |
794 | /* The argument type may be an array. Diagnose bounded string | |
795 | copy functions that specify the bound in terms of the source | |
bb0f14ae MS |
796 | argument rather than the destination unless they are equal |
797 | to one another. Handle constant sizes and also try to handle | |
798 | sizeof expressions involving VLAs. */ | |
025d57f0 MS |
799 | if (strop && !cmp && fncode != BUILT_IN_STRNDUP && src) |
800 | { | |
801 | tem = tree_strip_nop_conversions (src); | |
802 | if (TREE_CODE (tem) == ADDR_EXPR) | |
803 | tem = TREE_OPERAND (tem, 0); | |
bb0f14ae | 804 | |
4252ccd7 MS |
805 | /* Avoid diagnosing sizeof SRC when SRC is declared with |
806 | attribute nonstring. */ | |
807 | tree dummy; | |
808 | if (get_attr_nonstring_decl (tem, &dummy)) | |
809 | return; | |
810 | ||
bb0f14ae MS |
811 | tree d = tree_strip_nop_conversions (dest); |
812 | if (TREE_CODE (d) == ADDR_EXPR) | |
813 | d = TREE_OPERAND (d, 0); | |
814 | ||
815 | tree dstsz = TYPE_SIZE_UNIT (TREE_TYPE (d)); | |
816 | tree srcsz = TYPE_SIZE_UNIT (TREE_TYPE (tem)); | |
817 | ||
818 | if ((!dstsz | |
819 | || !srcsz | |
820 | || !operand_equal_p (dstsz, srcsz, OEP_LEXICOGRAPHIC)) | |
821 | && operand_equal_p (tem, sizeof_arg[idx], OEP_ADDRESS_OF)) | |
025d57f0 MS |
822 | warning_at (sizeof_arg_loc[idx], OPT_Wsizeof_pointer_memaccess, |
823 | "argument to %<sizeof%> in %qD call is the same " | |
824 | "expression as the source; did you mean to use " | |
825 | "the size of the destination?", | |
826 | callee); | |
827 | } | |
828 | ||
829 | return; | |
830 | } | |
038b5cc0 MP |
831 | |
832 | if (dest | |
833 | && (tem = tree_strip_nop_conversions (dest)) | |
834 | && POINTER_TYPE_P (TREE_TYPE (tem)) | |
835 | && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) | |
836 | return; | |
837 | ||
838 | if (src | |
839 | && (tem = tree_strip_nop_conversions (src)) | |
840 | && POINTER_TYPE_P (TREE_TYPE (tem)) | |
841 | && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) | |
842 | return; | |
843 | ||
844 | loc = sizeof_arg_loc[idx]; | |
845 | ||
846 | if (dest && !cmp) | |
847 | { | |
848 | if (!TYPE_P (sizeof_arg[idx]) | |
849 | && operand_equal_p (dest, sizeof_arg[idx], 0) | |
850 | && comp_types (TREE_TYPE (dest), type)) | |
851 | { | |
852 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
853 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
854 | "argument to %<sizeof%> in %qD call is the same " | |
855 | "expression as the destination; did you mean to " | |
856 | "remove the addressof?", callee); | |
857 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
858 | == TYPE_PRECISION (char_type_node)) | |
859 | || strop) | |
860 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
861 | "argument to %<sizeof%> in %qD call is the same " | |
862 | "expression as the destination; did you mean to " | |
863 | "provide an explicit length?", callee); | |
864 | else | |
865 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
866 | "argument to %<sizeof%> in %qD call is the same " | |
867 | "expression as the destination; did you mean to " | |
868 | "dereference it?", callee); | |
869 | return; | |
870 | } | |
871 | ||
872 | if (POINTER_TYPE_P (TREE_TYPE (dest)) | |
873 | && !strop | |
874 | && comp_types (TREE_TYPE (dest), type) | |
875 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
876 | { | |
877 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
878 | "argument to %<sizeof%> in %qD call is the same " | |
879 | "pointer type %qT as the destination; expected %qT " | |
880 | "or an explicit length", callee, TREE_TYPE (dest), | |
881 | TREE_TYPE (TREE_TYPE (dest))); | |
882 | return; | |
883 | } | |
884 | } | |
885 | ||
886 | if (src && !cmp) | |
887 | { | |
888 | if (!TYPE_P (sizeof_arg[idx]) | |
889 | && operand_equal_p (src, sizeof_arg[idx], 0) | |
890 | && comp_types (TREE_TYPE (src), type)) | |
891 | { | |
892 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
893 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
894 | "argument to %<sizeof%> in %qD call is the same " | |
895 | "expression as the source; did you mean to " | |
896 | "remove the addressof?", callee); | |
897 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
898 | == TYPE_PRECISION (char_type_node)) | |
899 | || strop) | |
900 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
901 | "argument to %<sizeof%> in %qD call is the same " | |
902 | "expression as the source; did you mean to " | |
903 | "provide an explicit length?", callee); | |
904 | else | |
905 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
906 | "argument to %<sizeof%> in %qD call is the same " | |
907 | "expression as the source; did you mean to " | |
908 | "dereference it?", callee); | |
909 | return; | |
910 | } | |
911 | ||
912 | if (POINTER_TYPE_P (TREE_TYPE (src)) | |
913 | && !strop | |
914 | && comp_types (TREE_TYPE (src), type) | |
915 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
916 | { | |
917 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
918 | "argument to %<sizeof%> in %qD call is the same " | |
919 | "pointer type %qT as the source; expected %qT " | |
920 | "or an explicit length", callee, TREE_TYPE (src), | |
921 | TREE_TYPE (TREE_TYPE (src))); | |
922 | return; | |
923 | } | |
924 | } | |
925 | ||
926 | if (dest) | |
927 | { | |
928 | if (!TYPE_P (sizeof_arg[idx]) | |
929 | && operand_equal_p (dest, sizeof_arg[idx], 0) | |
930 | && comp_types (TREE_TYPE (dest), type)) | |
931 | { | |
932 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
933 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
934 | "argument to %<sizeof%> in %qD call is the same " | |
935 | "expression as the first source; did you mean to " | |
936 | "remove the addressof?", callee); | |
937 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
938 | == TYPE_PRECISION (char_type_node)) | |
939 | || strop) | |
940 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
941 | "argument to %<sizeof%> in %qD call is the same " | |
942 | "expression as the first source; did you mean to " | |
943 | "provide an explicit length?", callee); | |
944 | else | |
945 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
946 | "argument to %<sizeof%> in %qD call is the same " | |
947 | "expression as the first source; did you mean to " | |
948 | "dereference it?", callee); | |
949 | return; | |
950 | } | |
951 | ||
952 | if (POINTER_TYPE_P (TREE_TYPE (dest)) | |
953 | && !strop | |
954 | && comp_types (TREE_TYPE (dest), type) | |
955 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
956 | { | |
957 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
958 | "argument to %<sizeof%> in %qD call is the same " | |
959 | "pointer type %qT as the first source; expected %qT " | |
960 | "or an explicit length", callee, TREE_TYPE (dest), | |
961 | TREE_TYPE (TREE_TYPE (dest))); | |
962 | return; | |
963 | } | |
964 | } | |
965 | ||
966 | if (src) | |
967 | { | |
968 | if (!TYPE_P (sizeof_arg[idx]) | |
969 | && operand_equal_p (src, sizeof_arg[idx], 0) | |
970 | && comp_types (TREE_TYPE (src), type)) | |
971 | { | |
972 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
973 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
974 | "argument to %<sizeof%> in %qD call is the same " | |
975 | "expression as the second source; did you mean to " | |
976 | "remove the addressof?", callee); | |
977 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
978 | == TYPE_PRECISION (char_type_node)) | |
979 | || strop) | |
980 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
981 | "argument to %<sizeof%> in %qD call is the same " | |
982 | "expression as the second source; did you mean to " | |
983 | "provide an explicit length?", callee); | |
984 | else | |
985 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
986 | "argument to %<sizeof%> in %qD call is the same " | |
987 | "expression as the second source; did you mean to " | |
988 | "dereference it?", callee); | |
989 | return; | |
990 | } | |
991 | ||
992 | if (POINTER_TYPE_P (TREE_TYPE (src)) | |
993 | && !strop | |
994 | && comp_types (TREE_TYPE (src), type) | |
995 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
996 | { | |
997 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
998 | "argument to %<sizeof%> in %qD call is the same " | |
999 | "pointer type %qT as the second source; expected %qT " | |
1000 | "or an explicit length", callee, TREE_TYPE (src), | |
1001 | TREE_TYPE (TREE_TYPE (src))); | |
1002 | return; | |
1003 | } | |
1004 | } | |
1005 | ||
1006 | } | |
1007 | ||
1008 | /* Warn for unlikely, improbable, or stupid DECL declarations | |
1009 | of `main'. */ | |
1010 | ||
1011 | void | |
1012 | check_main_parameter_types (tree decl) | |
1013 | { | |
1014 | function_args_iterator iter; | |
1015 | tree type; | |
1016 | int argct = 0; | |
1017 | ||
1018 | FOREACH_FUNCTION_ARGS (TREE_TYPE (decl), type, iter) | |
1019 | { | |
1020 | /* XXX void_type_node belies the abstraction. */ | |
1021 | if (type == void_type_node || type == error_mark_node) | |
1022 | break; | |
1023 | ||
1024 | tree t = type; | |
1025 | if (TYPE_ATOMIC (t)) | |
1026 | pedwarn (input_location, OPT_Wmain, | |
1027 | "%<_Atomic%>-qualified parameter type %qT of %q+D", | |
1028 | type, decl); | |
1029 | while (POINTER_TYPE_P (t)) | |
1030 | { | |
1031 | t = TREE_TYPE (t); | |
1032 | if (TYPE_ATOMIC (t)) | |
1033 | pedwarn (input_location, OPT_Wmain, | |
1034 | "%<_Atomic%>-qualified parameter type %qT of %q+D", | |
1035 | type, decl); | |
1036 | } | |
1037 | ||
1038 | ++argct; | |
1039 | switch (argct) | |
1040 | { | |
1041 | case 1: | |
1042 | if (TYPE_MAIN_VARIANT (type) != integer_type_node) | |
1043 | pedwarn (input_location, OPT_Wmain, | |
1044 | "first argument of %q+D should be %<int%>", decl); | |
1045 | break; | |
1046 | ||
1047 | case 2: | |
1048 | if (TREE_CODE (type) != POINTER_TYPE | |
1049 | || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE | |
1050 | || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type))) | |
1051 | != char_type_node)) | |
1052 | pedwarn (input_location, OPT_Wmain, | |
1053 | "second argument of %q+D should be %<char **%>", decl); | |
1054 | break; | |
1055 | ||
1056 | case 3: | |
1057 | if (TREE_CODE (type) != POINTER_TYPE | |
1058 | || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE | |
1059 | || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type))) | |
1060 | != char_type_node)) | |
1061 | pedwarn (input_location, OPT_Wmain, | |
1062 | "third argument of %q+D should probably be " | |
1063 | "%<char **%>", decl); | |
1064 | break; | |
1065 | } | |
1066 | } | |
1067 | ||
1068 | /* It is intentional that this message does not mention the third | |
1069 | argument because it's only mentioned in an appendix of the | |
1070 | standard. */ | |
1071 | if (argct > 0 && (argct < 2 || argct > 3)) | |
1072 | pedwarn (input_location, OPT_Wmain, | |
1073 | "%q+D takes only zero or two arguments", decl); | |
1074 | ||
1075 | if (stdarg_p (TREE_TYPE (decl))) | |
1076 | pedwarn (input_location, OPT_Wmain, | |
1077 | "%q+D declared as variadic function", decl); | |
1078 | } | |
1079 | ||
1080 | /* Warns if the conversion of EXPR to TYPE may alter a value. | |
1081 | This is a helper function for warnings_for_convert_and_check. */ | |
1082 | ||
1083 | static void | |
3cd211af | 1084 | conversion_warning (location_t loc, tree type, tree expr, tree result) |
038b5cc0 MP |
1085 | { |
1086 | tree expr_type = TREE_TYPE (expr); | |
1087 | enum conversion_safety conversion_kind; | |
1088 | ||
1089 | if (!warn_conversion && !warn_sign_conversion && !warn_float_conversion) | |
1090 | return; | |
1091 | ||
1092 | /* This may happen, because for LHS op= RHS we preevaluate | |
1093 | RHS and create C_MAYBE_CONST_EXPR <SAVE_EXPR <RHS>>, which | |
1094 | means we could no longer see the code of the EXPR. */ | |
1095 | if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR) | |
1096 | expr = C_MAYBE_CONST_EXPR_EXPR (expr); | |
1097 | if (TREE_CODE (expr) == SAVE_EXPR) | |
1098 | expr = TREE_OPERAND (expr, 0); | |
1099 | ||
1100 | switch (TREE_CODE (expr)) | |
1101 | { | |
1102 | case EQ_EXPR: | |
1103 | case NE_EXPR: | |
1104 | case LE_EXPR: | |
1105 | case GE_EXPR: | |
1106 | case LT_EXPR: | |
1107 | case GT_EXPR: | |
1108 | case TRUTH_ANDIF_EXPR: | |
1109 | case TRUTH_ORIF_EXPR: | |
1110 | case TRUTH_AND_EXPR: | |
1111 | case TRUTH_OR_EXPR: | |
1112 | case TRUTH_XOR_EXPR: | |
1113 | case TRUTH_NOT_EXPR: | |
1114 | /* Conversion from boolean to a signed:1 bit-field (which only | |
1115 | can hold the values 0 and -1) doesn't lose information - but | |
1116 | it does change the value. */ | |
1117 | if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type)) | |
1118 | warning_at (loc, OPT_Wconversion, | |
1119 | "conversion to %qT from boolean expression", type); | |
1120 | return; | |
1121 | ||
1122 | case REAL_CST: | |
1123 | case INTEGER_CST: | |
1124 | case COMPLEX_CST: | |
3cd211af MS |
1125 | { |
1126 | conversion_kind = unsafe_conversion_p (loc, type, expr, result, true); | |
1127 | int warnopt; | |
1128 | if (conversion_kind == UNSAFE_REAL) | |
1129 | warnopt = OPT_Wfloat_conversion; | |
1130 | else if (conversion_kind) | |
1131 | warnopt = OPT_Wconversion; | |
1132 | else | |
1133 | break; | |
038b5cc0 | 1134 | |
3cd211af MS |
1135 | if (TREE_CODE_CLASS (TREE_CODE (result)) == tcc_constant) |
1136 | warning_at (loc, warnopt, | |
1137 | "conversion from %qT to %qT changes value from %qE to %qE", | |
1138 | expr_type, type, expr, result); | |
1139 | else | |
1140 | warning_at (loc, warnopt, | |
1141 | "conversion from %qT to %qT changes the value of %qE", | |
1142 | expr_type, type, expr); | |
1143 | break; | |
1144 | } | |
038b5cc0 | 1145 | case COND_EXPR: |
3cd211af | 1146 | { |
038b5cc0 MP |
1147 | /* In case of COND_EXPR, we do not care about the type of |
1148 | COND_EXPR, only about the conversion of each operand. */ | |
1149 | tree op1 = TREE_OPERAND (expr, 1); | |
1150 | tree op2 = TREE_OPERAND (expr, 2); | |
1151 | ||
3cd211af MS |
1152 | conversion_warning (loc, type, op1, result); |
1153 | conversion_warning (loc, type, op2, result); | |
038b5cc0 MP |
1154 | return; |
1155 | } | |
1156 | ||
1157 | default: /* 'expr' is not a constant. */ | |
3cd211af MS |
1158 | conversion_kind = unsafe_conversion_p (loc, type, expr, result, true); |
1159 | if (conversion_kind == UNSAFE_IMAGINARY) | |
038b5cc0 | 1160 | warning_at (loc, OPT_Wconversion, |
ce811fc4 | 1161 | "conversion from %qT to %qT discards imaginary component", |
3cd211af | 1162 | expr_type, type); |
2474f48f MS |
1163 | else |
1164 | { | |
1165 | int warnopt; | |
1166 | if (conversion_kind == UNSAFE_REAL) | |
1167 | warnopt = OPT_Wfloat_conversion; | |
1168 | else if (conversion_kind) | |
1169 | warnopt = OPT_Wconversion; | |
1170 | else | |
1171 | break; | |
1172 | warning_at (loc, warnopt, | |
1173 | "conversion from %qT to %qT may change value", | |
1174 | expr_type, type); | |
1175 | } | |
038b5cc0 MP |
1176 | } |
1177 | } | |
1178 | ||
1179 | /* Produce warnings after a conversion. RESULT is the result of | |
1180 | converting EXPR to TYPE. This is a helper function for | |
1181 | convert_and_check and cp_convert_and_check. */ | |
1182 | ||
1183 | void | |
1184 | warnings_for_convert_and_check (location_t loc, tree type, tree expr, | |
1185 | tree result) | |
1186 | { | |
1187 | loc = expansion_point_location_if_in_system_header (loc); | |
1188 | ||
3cd211af MS |
1189 | bool cst = TREE_CODE_CLASS (TREE_CODE (result)) == tcc_constant; |
1190 | ||
1191 | tree exprtype = TREE_TYPE (expr); | |
1192 | ||
038b5cc0 MP |
1193 | if (TREE_CODE (expr) == INTEGER_CST |
1194 | && (TREE_CODE (type) == INTEGER_TYPE | |
1195 | || TREE_CODE (type) == ENUMERAL_TYPE) | |
1196 | && !int_fits_type_p (expr, type)) | |
1197 | { | |
1198 | /* Do not diagnose overflow in a constant expression merely | |
1199 | because a conversion overflowed. */ | |
1200 | if (TREE_OVERFLOW (result)) | |
1201 | TREE_OVERFLOW (result) = TREE_OVERFLOW (expr); | |
1202 | ||
1203 | if (TYPE_UNSIGNED (type)) | |
1204 | { | |
1205 | /* This detects cases like converting -129 or 256 to | |
1206 | unsigned char. */ | |
1207 | if (!int_fits_type_p (expr, c_common_signed_type (type))) | |
3cd211af MS |
1208 | { |
1209 | if (cst) | |
1210 | warning_at (loc, OPT_Woverflow, | |
1211 | (TYPE_UNSIGNED (exprtype) | |
1212 | ? G_("conversion from %qT to %qT " | |
1213 | "changes value from %qE to %qE") | |
1214 | : G_("unsigned conversion from %qT to %qT " | |
1215 | "changes value from %qE to %qE")), | |
1216 | exprtype, type, expr, result); | |
1217 | else | |
1218 | warning_at (loc, OPT_Woverflow, | |
1219 | (TYPE_UNSIGNED (exprtype) | |
1220 | ? G_("conversion from %qT to %qT " | |
1221 | "changes the value of %qE") | |
1222 | : G_("unsigned conversion from %qT to %qT " | |
1223 | "changes the value of %qE")), | |
1224 | exprtype, type, expr); | |
1225 | } | |
038b5cc0 | 1226 | else |
3cd211af | 1227 | conversion_warning (loc, type, expr, result); |
038b5cc0 MP |
1228 | } |
1229 | else if (!int_fits_type_p (expr, c_common_unsigned_type (type))) | |
3cd211af MS |
1230 | { |
1231 | if (cst) | |
1232 | warning_at (loc, OPT_Woverflow, | |
1233 | "overflow in conversion from %qT to %qT " | |
1234 | "changes value from %qE to %qE", | |
1235 | exprtype, type, expr, result); | |
1236 | else | |
1237 | warning_at (loc, OPT_Woverflow, | |
1238 | "overflow in conversion from %qT to %qT " | |
1239 | "changes the value of %qE", | |
1240 | exprtype, type, expr); | |
1241 | } | |
038b5cc0 MP |
1242 | /* No warning for converting 0x80000000 to int. */ |
1243 | else if (pedantic | |
3cd211af MS |
1244 | && (TREE_CODE (exprtype) != INTEGER_TYPE |
1245 | || TYPE_PRECISION (exprtype) | |
038b5cc0 | 1246 | != TYPE_PRECISION (type))) |
3cd211af MS |
1247 | { |
1248 | if (cst) | |
1249 | warning_at (loc, OPT_Woverflow, | |
1250 | "overflow in conversion from %qT to %qT " | |
1251 | "changes value from %qE to %qE", | |
1252 | exprtype, type, expr, result); | |
1253 | else | |
1254 | warning_at (loc, OPT_Woverflow, | |
1255 | "overflow in conversion from %qT to %qT " | |
1256 | "changes the value of %qE", | |
1257 | exprtype, type, expr); | |
1258 | } | |
038b5cc0 | 1259 | else |
3cd211af | 1260 | conversion_warning (loc, type, expr, result); |
038b5cc0 MP |
1261 | } |
1262 | else if ((TREE_CODE (result) == INTEGER_CST | |
1263 | || TREE_CODE (result) == FIXED_CST) && TREE_OVERFLOW (result)) | |
3cd211af MS |
1264 | { |
1265 | if (cst) | |
1266 | warning_at (loc, OPT_Woverflow, | |
1267 | "overflow in conversion from %qT to %qT " | |
d1047465 | 1268 | "changes value from %qE to %qE", |
3cd211af MS |
1269 | exprtype, type, expr, result); |
1270 | else | |
1271 | warning_at (loc, OPT_Woverflow, | |
1272 | "overflow in conversion from %qT to %qT " | |
d1047465 | 1273 | "changes the value of %qE", |
3cd211af MS |
1274 | exprtype, type, expr); |
1275 | } | |
038b5cc0 | 1276 | else |
3cd211af | 1277 | conversion_warning (loc, type, expr, result); |
038b5cc0 MP |
1278 | } |
1279 | ||
1280 | /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach. | |
1281 | Used to verify that case values match up with enumerator values. */ | |
1282 | ||
1283 | static void | |
1284 | match_case_to_enum_1 (tree key, tree type, tree label) | |
1285 | { | |
1ff7be5a JM |
1286 | /* Avoid warning about enums that have no enumerators. */ |
1287 | if (TYPE_VALUES (type) == NULL_TREE) | |
1288 | return; | |
1289 | ||
038b5cc0 MP |
1290 | char buf[WIDE_INT_PRINT_BUFFER_SIZE]; |
1291 | ||
1292 | if (tree_fits_uhwi_p (key)) | |
8e6cdc90 | 1293 | print_dec (wi::to_wide (key), buf, UNSIGNED); |
038b5cc0 | 1294 | else if (tree_fits_shwi_p (key)) |
8e6cdc90 | 1295 | print_dec (wi::to_wide (key), buf, SIGNED); |
038b5cc0 | 1296 | else |
8e6cdc90 | 1297 | print_hex (wi::to_wide (key), buf); |
038b5cc0 | 1298 | |
3fa8871b | 1299 | if (TYPE_NAME (type) == NULL_TREE) |
038b5cc0 MP |
1300 | warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label)), |
1301 | warn_switch ? OPT_Wswitch : OPT_Wswitch_enum, | |
1302 | "case value %qs not in enumerated type", | |
1303 | buf); | |
1304 | else | |
1305 | warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label)), | |
1306 | warn_switch ? OPT_Wswitch : OPT_Wswitch_enum, | |
1307 | "case value %qs not in enumerated type %qT", | |
1308 | buf, type); | |
1309 | } | |
1310 | ||
1311 | /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach. | |
1312 | Used to verify that case values match up with enumerator values. */ | |
1313 | ||
1314 | static int | |
1315 | match_case_to_enum (splay_tree_node node, void *data) | |
1316 | { | |
1317 | tree label = (tree) node->value; | |
1318 | tree type = (tree) data; | |
1319 | ||
1320 | /* Skip default case. */ | |
1321 | if (!CASE_LOW (label)) | |
1322 | return 0; | |
1323 | ||
1324 | /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear | |
1325 | when we did our enum->case scan. Reset our scratch bit after. */ | |
1326 | if (!CASE_LOW_SEEN (label)) | |
1327 | match_case_to_enum_1 (CASE_LOW (label), type, label); | |
1328 | else | |
1329 | CASE_LOW_SEEN (label) = 0; | |
1330 | ||
1331 | /* If CASE_HIGH is non-null, we have a range. If CASE_HIGH_SEEN is | |
1332 | not set, that means that CASE_HIGH did not appear when we did our | |
1333 | enum->case scan. Reset our scratch bit after. */ | |
1334 | if (CASE_HIGH (label)) | |
1335 | { | |
1336 | if (!CASE_HIGH_SEEN (label)) | |
1337 | match_case_to_enum_1 (CASE_HIGH (label), type, label); | |
1338 | else | |
1339 | CASE_HIGH_SEEN (label) = 0; | |
1340 | } | |
1341 | ||
1342 | return 0; | |
1343 | } | |
1344 | ||
1345 | /* Handle -Wswitch*. Called from the front end after parsing the | |
1346 | switch construct. */ | |
1347 | /* ??? Should probably be somewhere generic, since other languages | |
1348 | besides C and C++ would want this. At the moment, however, C/C++ | |
1349 | are the only tree-ssa languages that support enumerations at all, | |
1350 | so the point is moot. */ | |
1351 | ||
1352 | void | |
1353 | c_do_switch_warnings (splay_tree cases, location_t switch_location, | |
1354 | tree type, tree cond, bool bool_cond_p, | |
1355 | bool outside_range_p) | |
1356 | { | |
1357 | splay_tree_node default_node; | |
1358 | splay_tree_node node; | |
1359 | tree chain; | |
1360 | ||
1361 | if (!warn_switch && !warn_switch_enum && !warn_switch_default | |
1362 | && !warn_switch_bool) | |
1363 | return; | |
1364 | ||
1365 | default_node = splay_tree_lookup (cases, (splay_tree_key) NULL); | |
1366 | if (!default_node) | |
1367 | warning_at (switch_location, OPT_Wswitch_default, | |
1368 | "switch missing default case"); | |
1369 | ||
1370 | /* There are certain cases where -Wswitch-bool warnings aren't | |
1371 | desirable, such as | |
1372 | switch (boolean) | |
1373 | { | |
1374 | case true: ... | |
1375 | case false: ... | |
1376 | } | |
1377 | so be careful here. */ | |
1378 | if (warn_switch_bool && bool_cond_p) | |
1379 | { | |
1380 | splay_tree_node min_node; | |
1381 | /* If there's a default node, it's also the value with the minimal | |
1382 | key. So look at the penultimate key (if any). */ | |
1383 | if (default_node) | |
1384 | min_node = splay_tree_successor (cases, (splay_tree_key) NULL); | |
1385 | else | |
1386 | min_node = splay_tree_min (cases); | |
1387 | tree min = min_node ? (tree) min_node->key : NULL_TREE; | |
1388 | ||
1389 | splay_tree_node max_node = splay_tree_max (cases); | |
1390 | /* This might be a case range, so look at the value with the | |
1391 | maximal key and then check CASE_HIGH. */ | |
1392 | tree max = max_node ? (tree) max_node->value : NULL_TREE; | |
1393 | if (max) | |
1394 | max = CASE_HIGH (max) ? CASE_HIGH (max) : CASE_LOW (max); | |
1395 | ||
1396 | /* If there's a case value > 1 or < 0, that is outside bool | |
1397 | range, warn. */ | |
1398 | if (outside_range_p | |
8e6cdc90 RS |
1399 | || (max && wi::gts_p (wi::to_wide (max), 1)) |
1400 | || (min && wi::lts_p (wi::to_wide (min), 0)) | |
038b5cc0 MP |
1401 | /* And handle the |
1402 | switch (boolean) | |
1403 | { | |
1404 | case true: ... | |
1405 | case false: ... | |
1406 | default: ... | |
1407 | } | |
1408 | case, where we want to warn. */ | |
1409 | || (default_node | |
8e6cdc90 RS |
1410 | && max && wi::to_wide (max) == 1 |
1411 | && min && wi::to_wide (min) == 0)) | |
038b5cc0 MP |
1412 | warning_at (switch_location, OPT_Wswitch_bool, |
1413 | "switch condition has boolean value"); | |
1414 | } | |
1415 | ||
1416 | /* From here on, we only care about enumerated types. */ | |
1417 | if (!type || TREE_CODE (type) != ENUMERAL_TYPE) | |
1418 | return; | |
1419 | ||
1420 | /* From here on, we only care about -Wswitch and -Wswitch-enum. */ | |
1421 | if (!warn_switch_enum && !warn_switch) | |
1422 | return; | |
1423 | ||
1424 | /* Check the cases. Warn about case values which are not members of | |
1425 | the enumerated type. For -Wswitch-enum, or for -Wswitch when | |
1426 | there is no default case, check that exactly all enumeration | |
1427 | literals are covered by the cases. */ | |
1428 | ||
1429 | /* Clearing COND if it is not an integer constant simplifies | |
1430 | the tests inside the loop below. */ | |
1431 | if (TREE_CODE (cond) != INTEGER_CST) | |
1432 | cond = NULL_TREE; | |
1433 | ||
1434 | /* The time complexity here is O(N*lg(N)) worst case, but for the | |
1435 | common case of monotonically increasing enumerators, it is | |
1436 | O(N), since the nature of the splay tree will keep the next | |
1437 | element adjacent to the root at all times. */ | |
1438 | ||
1439 | for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain)) | |
1440 | { | |
1441 | tree value = TREE_VALUE (chain); | |
1442 | if (TREE_CODE (value) == CONST_DECL) | |
1443 | value = DECL_INITIAL (value); | |
1444 | node = splay_tree_lookup (cases, (splay_tree_key) value); | |
1445 | if (node) | |
1446 | { | |
1447 | /* Mark the CASE_LOW part of the case entry as seen. */ | |
1448 | tree label = (tree) node->value; | |
1449 | CASE_LOW_SEEN (label) = 1; | |
1450 | continue; | |
1451 | } | |
1452 | ||
1453 | /* Even though there wasn't an exact match, there might be a | |
1454 | case range which includes the enumerator's value. */ | |
1455 | node = splay_tree_predecessor (cases, (splay_tree_key) value); | |
1456 | if (node && CASE_HIGH ((tree) node->value)) | |
1457 | { | |
1458 | tree label = (tree) node->value; | |
1459 | int cmp = tree_int_cst_compare (CASE_HIGH (label), value); | |
1460 | if (cmp >= 0) | |
1461 | { | |
1462 | /* If we match the upper bound exactly, mark the CASE_HIGH | |
1463 | part of the case entry as seen. */ | |
1464 | if (cmp == 0) | |
1465 | CASE_HIGH_SEEN (label) = 1; | |
1466 | continue; | |
1467 | } | |
1468 | } | |
1469 | ||
1470 | /* We've now determined that this enumerated literal isn't | |
1471 | handled by the case labels of the switch statement. */ | |
1472 | ||
1473 | /* If the switch expression is a constant, we only really care | |
1474 | about whether that constant is handled by the switch. */ | |
1475 | if (cond && tree_int_cst_compare (cond, value)) | |
1476 | continue; | |
1477 | ||
1478 | /* If there is a default_node, the only relevant option is | |
1479 | Wswitch-enum. Otherwise, if both are enabled then we prefer | |
1480 | to warn using -Wswitch because -Wswitch is enabled by -Wall | |
1481 | while -Wswitch-enum is explicit. */ | |
1482 | warning_at (switch_location, | |
1483 | (default_node || !warn_switch | |
1484 | ? OPT_Wswitch_enum | |
1485 | : OPT_Wswitch), | |
1486 | "enumeration value %qE not handled in switch", | |
1487 | TREE_PURPOSE (chain)); | |
1488 | } | |
1489 | ||
1490 | /* Warn if there are case expressions that don't correspond to | |
1491 | enumerators. This can occur since C and C++ don't enforce | |
1492 | type-checking of assignments to enumeration variables. | |
1493 | ||
1494 | The time complexity here is now always O(N) worst case, since | |
1495 | we should have marked both the lower bound and upper bound of | |
1496 | every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN | |
1497 | above. This scan also resets those fields. */ | |
1498 | ||
1499 | splay_tree_foreach (cases, match_case_to_enum, type); | |
1500 | } | |
1501 | ||
1502 | /* Warn for A ?: C expressions (with B omitted) where A is a boolean | |
1503 | expression, because B will always be true. */ | |
1504 | ||
1505 | void | |
1506 | warn_for_omitted_condop (location_t location, tree cond) | |
1507 | { | |
1508 | /* In C++ template declarations it can happen that the type is dependent | |
1509 | and not yet known, thus TREE_TYPE (cond) == NULL_TREE. */ | |
1510 | if (truth_value_p (TREE_CODE (cond)) | |
1511 | || (TREE_TYPE (cond) != NULL_TREE | |
1512 | && TREE_CODE (TREE_TYPE (cond)) == BOOLEAN_TYPE)) | |
1513 | warning_at (location, OPT_Wparentheses, | |
1514 | "the omitted middle operand in ?: will always be %<true%>, " | |
1515 | "suggest explicit middle operand"); | |
1516 | } | |
1517 | ||
1518 | /* Give an error for storing into ARG, which is 'const'. USE indicates | |
1519 | how ARG was being used. */ | |
1520 | ||
1521 | void | |
1522 | readonly_error (location_t loc, tree arg, enum lvalue_use use) | |
1523 | { | |
1524 | gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement | |
1525 | || use == lv_asm); | |
1526 | /* Using this macro rather than (for example) arrays of messages | |
1527 | ensures that all the format strings are checked at compile | |
1528 | time. */ | |
1529 | #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A) \ | |
1530 | : (use == lv_increment ? (I) \ | |
1531 | : (use == lv_decrement ? (D) : (AS)))) | |
1532 | if (TREE_CODE (arg) == COMPONENT_REF) | |
1533 | { | |
1534 | if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0)))) | |
1535 | error_at (loc, READONLY_MSG (G_("assignment of member " | |
1536 | "%qD in read-only object"), | |
1537 | G_("increment of member " | |
1538 | "%qD in read-only object"), | |
1539 | G_("decrement of member " | |
1540 | "%qD in read-only object"), | |
1541 | G_("member %qD in read-only object " | |
1542 | "used as %<asm%> output")), | |
1543 | TREE_OPERAND (arg, 1)); | |
1544 | else | |
1545 | error_at (loc, READONLY_MSG (G_("assignment of read-only member %qD"), | |
1546 | G_("increment of read-only member %qD"), | |
1547 | G_("decrement of read-only member %qD"), | |
1548 | G_("read-only member %qD used as %<asm%> output")), | |
1549 | TREE_OPERAND (arg, 1)); | |
1550 | } | |
1551 | else if (VAR_P (arg)) | |
1552 | error_at (loc, READONLY_MSG (G_("assignment of read-only variable %qD"), | |
1553 | G_("increment of read-only variable %qD"), | |
1554 | G_("decrement of read-only variable %qD"), | |
1555 | G_("read-only variable %qD used as %<asm%> output")), | |
1556 | arg); | |
1557 | else if (TREE_CODE (arg) == PARM_DECL) | |
1558 | error_at (loc, READONLY_MSG (G_("assignment of read-only parameter %qD"), | |
1559 | G_("increment of read-only parameter %qD"), | |
1560 | G_("decrement of read-only parameter %qD"), | |
1561 | G_("read-only parameter %qD use as %<asm%> output")), | |
1562 | arg); | |
1563 | else if (TREE_CODE (arg) == RESULT_DECL) | |
1564 | { | |
1565 | gcc_assert (c_dialect_cxx ()); | |
1566 | error_at (loc, READONLY_MSG (G_("assignment of " | |
1567 | "read-only named return value %qD"), | |
1568 | G_("increment of " | |
1569 | "read-only named return value %qD"), | |
1570 | G_("decrement of " | |
1571 | "read-only named return value %qD"), | |
1572 | G_("read-only named return value %qD " | |
1573 | "used as %<asm%>output")), | |
1574 | arg); | |
1575 | } | |
1576 | else if (TREE_CODE (arg) == FUNCTION_DECL) | |
1577 | error_at (loc, READONLY_MSG (G_("assignment of function %qD"), | |
1578 | G_("increment of function %qD"), | |
1579 | G_("decrement of function %qD"), | |
1580 | G_("function %qD used as %<asm%> output")), | |
1581 | arg); | |
1582 | else | |
1583 | error_at (loc, READONLY_MSG (G_("assignment of read-only location %qE"), | |
1584 | G_("increment of read-only location %qE"), | |
1585 | G_("decrement of read-only location %qE"), | |
1586 | G_("read-only location %qE used as %<asm%> output")), | |
1587 | arg); | |
1588 | } | |
1589 | ||
1590 | /* Print an error message for an invalid lvalue. USE says | |
1591 | how the lvalue is being used and so selects the error message. LOC | |
1592 | is the location for the error. */ | |
1593 | ||
1594 | void | |
1595 | lvalue_error (location_t loc, enum lvalue_use use) | |
1596 | { | |
1597 | switch (use) | |
1598 | { | |
1599 | case lv_assign: | |
1600 | error_at (loc, "lvalue required as left operand of assignment"); | |
1601 | break; | |
1602 | case lv_increment: | |
1603 | error_at (loc, "lvalue required as increment operand"); | |
1604 | break; | |
1605 | case lv_decrement: | |
1606 | error_at (loc, "lvalue required as decrement operand"); | |
1607 | break; | |
1608 | case lv_addressof: | |
1609 | error_at (loc, "lvalue required as unary %<&%> operand"); | |
1610 | break; | |
1611 | case lv_asm: | |
1612 | error_at (loc, "lvalue required in asm statement"); | |
1613 | break; | |
1614 | default: | |
1615 | gcc_unreachable (); | |
1616 | } | |
1617 | } | |
1618 | ||
1619 | /* Print an error message for an invalid indirection of type TYPE. | |
1620 | ERRSTRING is the name of the operator for the indirection. */ | |
1621 | ||
1622 | void | |
1623 | invalid_indirection_error (location_t loc, tree type, ref_operator errstring) | |
1624 | { | |
1625 | switch (errstring) | |
1626 | { | |
1627 | case RO_NULL: | |
1628 | gcc_assert (c_dialect_cxx ()); | |
1629 | error_at (loc, "invalid type argument (have %qT)", type); | |
1630 | break; | |
1631 | case RO_ARRAY_INDEXING: | |
1632 | error_at (loc, | |
1633 | "invalid type argument of array indexing (have %qT)", | |
1634 | type); | |
1635 | break; | |
1636 | case RO_UNARY_STAR: | |
1637 | error_at (loc, | |
1638 | "invalid type argument of unary %<*%> (have %qT)", | |
1639 | type); | |
1640 | break; | |
1641 | case RO_ARROW: | |
1642 | error_at (loc, | |
1643 | "invalid type argument of %<->%> (have %qT)", | |
1644 | type); | |
1645 | break; | |
1646 | case RO_ARROW_STAR: | |
1647 | error_at (loc, | |
1648 | "invalid type argument of %<->*%> (have %qT)", | |
1649 | type); | |
1650 | break; | |
1651 | case RO_IMPLICIT_CONVERSION: | |
1652 | error_at (loc, | |
1653 | "invalid type argument of implicit conversion (have %qT)", | |
1654 | type); | |
1655 | break; | |
1656 | default: | |
1657 | gcc_unreachable (); | |
1658 | } | |
1659 | } | |
1660 | ||
1661 | /* Subscripting with type char is likely to lose on a machine where | |
1662 | chars are signed. So warn on any machine, but optionally. Don't | |
1663 | warn for unsigned char since that type is safe. Don't warn for | |
1664 | signed char because anyone who uses that must have done so | |
1665 | deliberately. Furthermore, we reduce the false positive load by | |
1666 | warning only for non-constant value of type char. */ | |
1667 | ||
1668 | void | |
1669 | warn_array_subscript_with_type_char (location_t loc, tree index) | |
1670 | { | |
1671 | if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node | |
1672 | && TREE_CODE (index) != INTEGER_CST) | |
1673 | warning_at (loc, OPT_Wchar_subscripts, | |
1674 | "array subscript has type %<char%>"); | |
1675 | } | |
1676 | ||
1677 | /* Implement -Wparentheses for the unexpected C precedence rules, to | |
1678 | cover cases like x + y << z which readers are likely to | |
1679 | misinterpret. We have seen an expression in which CODE is a binary | |
1680 | operator used to combine expressions ARG_LEFT and ARG_RIGHT, which | |
1681 | before folding had CODE_LEFT and CODE_RIGHT. CODE_LEFT and | |
1682 | CODE_RIGHT may be ERROR_MARK, which means that that side of the | |
1683 | expression was not formed using a binary or unary operator, or it | |
1684 | was enclosed in parentheses. */ | |
1685 | ||
1686 | void | |
1687 | warn_about_parentheses (location_t loc, enum tree_code code, | |
1688 | enum tree_code code_left, tree arg_left, | |
1689 | enum tree_code code_right, tree arg_right) | |
1690 | { | |
1691 | if (!warn_parentheses) | |
1692 | return; | |
1693 | ||
1694 | /* This macro tests that the expression ARG with original tree code | |
1695 | CODE appears to be a boolean expression. or the result of folding a | |
1696 | boolean expression. */ | |
1697 | #define APPEARS_TO_BE_BOOLEAN_EXPR_P(CODE, ARG) \ | |
1698 | (truth_value_p (TREE_CODE (ARG)) \ | |
1699 | || TREE_CODE (TREE_TYPE (ARG)) == BOOLEAN_TYPE \ | |
1700 | /* Folding may create 0 or 1 integers from other expressions. */ \ | |
1701 | || ((CODE) != INTEGER_CST \ | |
1702 | && (integer_onep (ARG) || integer_zerop (ARG)))) | |
1703 | ||
1704 | switch (code) | |
1705 | { | |
1706 | case LSHIFT_EXPR: | |
1707 | if (code_left == PLUS_EXPR) | |
1708 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1709 | "suggest parentheses around %<+%> inside %<<<%>"); | |
1710 | else if (code_right == PLUS_EXPR) | |
1711 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1712 | "suggest parentheses around %<+%> inside %<<<%>"); | |
1713 | else if (code_left == MINUS_EXPR) | |
1714 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1715 | "suggest parentheses around %<-%> inside %<<<%>"); | |
1716 | else if (code_right == MINUS_EXPR) | |
1717 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1718 | "suggest parentheses around %<-%> inside %<<<%>"); | |
1719 | return; | |
1720 | ||
1721 | case RSHIFT_EXPR: | |
1722 | if (code_left == PLUS_EXPR) | |
1723 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1724 | "suggest parentheses around %<+%> inside %<>>%>"); | |
1725 | else if (code_right == PLUS_EXPR) | |
1726 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1727 | "suggest parentheses around %<+%> inside %<>>%>"); | |
1728 | else if (code_left == MINUS_EXPR) | |
1729 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1730 | "suggest parentheses around %<-%> inside %<>>%>"); | |
1731 | else if (code_right == MINUS_EXPR) | |
1732 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1733 | "suggest parentheses around %<-%> inside %<>>%>"); | |
1734 | return; | |
1735 | ||
1736 | case TRUTH_ORIF_EXPR: | |
1737 | if (code_left == TRUTH_ANDIF_EXPR) | |
1738 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1739 | "suggest parentheses around %<&&%> within %<||%>"); | |
1740 | else if (code_right == TRUTH_ANDIF_EXPR) | |
1741 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1742 | "suggest parentheses around %<&&%> within %<||%>"); | |
1743 | return; | |
1744 | ||
1745 | case BIT_IOR_EXPR: | |
1746 | if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR | |
1747 | || code_left == PLUS_EXPR || code_left == MINUS_EXPR) | |
1748 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1749 | "suggest parentheses around arithmetic in operand of %<|%>"); | |
1750 | else if (code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR | |
1751 | || code_right == PLUS_EXPR || code_right == MINUS_EXPR) | |
1752 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1753 | "suggest parentheses around arithmetic in operand of %<|%>"); | |
1754 | /* Check cases like x|y==z */ | |
1755 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1756 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1757 | "suggest parentheses around comparison in operand of %<|%>"); | |
1758 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1759 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1760 | "suggest parentheses around comparison in operand of %<|%>"); | |
1761 | /* Check cases like !x | y */ | |
1762 | else if (code_left == TRUTH_NOT_EXPR | |
1763 | && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right, arg_right)) | |
1764 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1765 | "suggest parentheses around operand of " | |
1766 | "%<!%> or change %<|%> to %<||%> or %<!%> to %<~%>"); | |
1767 | return; | |
1768 | ||
1769 | case BIT_XOR_EXPR: | |
1770 | if (code_left == BIT_AND_EXPR | |
1771 | || code_left == PLUS_EXPR || code_left == MINUS_EXPR) | |
1772 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1773 | "suggest parentheses around arithmetic in operand of %<^%>"); | |
1774 | else if (code_right == BIT_AND_EXPR | |
1775 | || code_right == PLUS_EXPR || code_right == MINUS_EXPR) | |
1776 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1777 | "suggest parentheses around arithmetic in operand of %<^%>"); | |
1778 | /* Check cases like x^y==z */ | |
1779 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1780 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1781 | "suggest parentheses around comparison in operand of %<^%>"); | |
1782 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1783 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1784 | "suggest parentheses around comparison in operand of %<^%>"); | |
1785 | return; | |
1786 | ||
1787 | case BIT_AND_EXPR: | |
1788 | if (code_left == PLUS_EXPR) | |
1789 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1790 | "suggest parentheses around %<+%> in operand of %<&%>"); | |
1791 | else if (code_right == PLUS_EXPR) | |
1792 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1793 | "suggest parentheses around %<+%> in operand of %<&%>"); | |
1794 | else if (code_left == MINUS_EXPR) | |
1795 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1796 | "suggest parentheses around %<-%> in operand of %<&%>"); | |
1797 | else if (code_right == MINUS_EXPR) | |
1798 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1799 | "suggest parentheses around %<-%> in operand of %<&%>"); | |
1800 | /* Check cases like x&y==z */ | |
1801 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1802 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1803 | "suggest parentheses around comparison in operand of %<&%>"); | |
1804 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1805 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1806 | "suggest parentheses around comparison in operand of %<&%>"); | |
1807 | /* Check cases like !x & y */ | |
1808 | else if (code_left == TRUTH_NOT_EXPR | |
1809 | && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right, arg_right)) | |
1810 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1811 | "suggest parentheses around operand of " | |
1812 | "%<!%> or change %<&%> to %<&&%> or %<!%> to %<~%>"); | |
1813 | return; | |
1814 | ||
1815 | case EQ_EXPR: | |
1816 | if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1817 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1818 | "suggest parentheses around comparison in operand of %<==%>"); | |
1819 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1820 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1821 | "suggest parentheses around comparison in operand of %<==%>"); | |
1822 | return; | |
1823 | case NE_EXPR: | |
1824 | if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1825 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1826 | "suggest parentheses around comparison in operand of %<!=%>"); | |
1827 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1828 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1829 | "suggest parentheses around comparison in operand of %<!=%>"); | |
1830 | return; | |
1831 | ||
1832 | default: | |
1833 | if (TREE_CODE_CLASS (code) == tcc_comparison) | |
1834 | { | |
1835 | if (TREE_CODE_CLASS (code_left) == tcc_comparison | |
1836 | && code_left != NE_EXPR && code_left != EQ_EXPR | |
1837 | && INTEGRAL_TYPE_P (TREE_TYPE (arg_left))) | |
1838 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1839 | "comparisons like %<X<=Y<=Z%> do not " | |
1840 | "have their mathematical meaning"); | |
1841 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison | |
1842 | && code_right != NE_EXPR && code_right != EQ_EXPR | |
1843 | && INTEGRAL_TYPE_P (TREE_TYPE (arg_right))) | |
1844 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1845 | "comparisons like %<X<=Y<=Z%> do not " | |
1846 | "have their mathematical meaning"); | |
1847 | } | |
1848 | return; | |
1849 | } | |
1850 | #undef NOT_A_BOOLEAN_EXPR_P | |
1851 | } | |
1852 | ||
1853 | /* If LABEL (a LABEL_DECL) has not been used, issue a warning. */ | |
1854 | ||
1855 | void | |
1856 | warn_for_unused_label (tree label) | |
1857 | { | |
1858 | if (!TREE_USED (label)) | |
1859 | { | |
1860 | if (DECL_INITIAL (label)) | |
1861 | warning (OPT_Wunused_label, "label %q+D defined but not used", label); | |
1862 | else | |
1863 | warning (OPT_Wunused_label, "label %q+D declared but not defined", label); | |
1864 | } | |
6dc4a604 ML |
1865 | else if (asan_sanitize_use_after_scope ()) |
1866 | { | |
1867 | if (asan_used_labels == NULL) | |
1868 | asan_used_labels = new hash_set<tree> (16); | |
1869 | ||
1870 | asan_used_labels->add (label); | |
1871 | } | |
038b5cc0 MP |
1872 | } |
1873 | ||
1874 | /* Warn for division by zero according to the value of DIVISOR. LOC | |
1875 | is the location of the division operator. */ | |
1876 | ||
1877 | void | |
1878 | warn_for_div_by_zero (location_t loc, tree divisor) | |
1879 | { | |
1880 | /* If DIVISOR is zero, and has integral or fixed-point type, issue a warning | |
1881 | about division by zero. Do not issue a warning if DIVISOR has a | |
1882 | floating-point type, since we consider 0.0/0.0 a valid way of | |
1883 | generating a NaN. */ | |
1884 | if (c_inhibit_evaluation_warnings == 0 | |
1885 | && (integer_zerop (divisor) || fixed_zerop (divisor))) | |
1886 | warning_at (loc, OPT_Wdiv_by_zero, "division by zero"); | |
1887 | } | |
1888 | ||
1889 | /* Warn for patterns where memset appears to be used incorrectly. The | |
1890 | warning location should be LOC. ARG0, and ARG2 are the first and | |
1891 | last arguments to the call, while LITERAL_ZERO_MASK has a 1 bit for | |
1892 | each argument that was a literal zero. */ | |
1893 | ||
1894 | void | |
1895 | warn_for_memset (location_t loc, tree arg0, tree arg2, | |
1896 | int literal_zero_mask) | |
1897 | { | |
9a004410 DM |
1898 | arg0 = fold_for_warn (arg0); |
1899 | arg2 = fold_for_warn (arg2); | |
1900 | ||
038b5cc0 MP |
1901 | if (warn_memset_transposed_args |
1902 | && integer_zerop (arg2) | |
1903 | && (literal_zero_mask & (1 << 2)) != 0 | |
1904 | && (literal_zero_mask & (1 << 1)) == 0) | |
1905 | warning_at (loc, OPT_Wmemset_transposed_args, | |
1906 | "%<memset%> used with constant zero length " | |
1907 | "parameter; this could be due to transposed " | |
1908 | "parameters"); | |
1909 | ||
1910 | if (warn_memset_elt_size && TREE_CODE (arg2) == INTEGER_CST) | |
1911 | { | |
1912 | STRIP_NOPS (arg0); | |
1913 | if (TREE_CODE (arg0) == ADDR_EXPR) | |
1914 | arg0 = TREE_OPERAND (arg0, 0); | |
1915 | tree type = TREE_TYPE (arg0); | |
1916 | if (type != NULL_TREE && TREE_CODE (type) == ARRAY_TYPE) | |
1917 | { | |
1918 | tree elt_type = TREE_TYPE (type); | |
1919 | tree domain = TYPE_DOMAIN (type); | |
4dbdb49b JM |
1920 | if (COMPLETE_TYPE_P (elt_type) |
1921 | && !integer_onep (TYPE_SIZE_UNIT (elt_type)) | |
038b5cc0 | 1922 | && domain != NULL_TREE |
ff22eb12 NS |
1923 | && TYPE_MAX_VALUE (domain) |
1924 | && TYPE_MIN_VALUE (domain) | |
1925 | && integer_zerop (TYPE_MIN_VALUE (domain)) | |
038b5cc0 MP |
1926 | && integer_onep (fold_build2 (MINUS_EXPR, domain, |
1927 | arg2, | |
ff22eb12 | 1928 | TYPE_MAX_VALUE (domain)))) |
038b5cc0 MP |
1929 | warning_at (loc, OPT_Wmemset_elt_size, |
1930 | "%<memset%> used with length equal to " | |
1931 | "number of elements without multiplication " | |
1932 | "by element size"); | |
1933 | } | |
1934 | } | |
1935 | } | |
1936 | ||
1937 | /* Subroutine of build_binary_op. Give warnings for comparisons | |
1938 | between signed and unsigned quantities that may fail. Do the | |
1939 | checking based on the original operand trees ORIG_OP0 and ORIG_OP1, | |
1940 | so that casts will be considered, but default promotions won't | |
1941 | be. | |
1942 | ||
1943 | LOCATION is the location of the comparison operator. | |
1944 | ||
1945 | The arguments of this function map directly to local variables | |
1946 | of build_binary_op. */ | |
1947 | ||
1948 | void | |
1949 | warn_for_sign_compare (location_t location, | |
1950 | tree orig_op0, tree orig_op1, | |
1951 | tree op0, tree op1, | |
1952 | tree result_type, enum tree_code resultcode) | |
1953 | { | |
0805d020 MP |
1954 | if (error_operand_p (orig_op0) || error_operand_p (orig_op1)) |
1955 | return; | |
1956 | ||
038b5cc0 MP |
1957 | int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0)); |
1958 | int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1)); | |
1959 | int unsignedp0, unsignedp1; | |
1960 | ||
1961 | /* In C++, check for comparison of different enum types. */ | |
1962 | if (c_dialect_cxx() | |
1963 | && TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE | |
1964 | && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE | |
1965 | && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0)) | |
1966 | != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1))) | |
1967 | { | |
1968 | warning_at (location, | |
1969 | OPT_Wsign_compare, "comparison between types %qT and %qT", | |
1970 | TREE_TYPE (orig_op0), TREE_TYPE (orig_op1)); | |
1971 | } | |
1972 | ||
1973 | /* Do not warn if the comparison is being done in a signed type, | |
1974 | since the signed type will only be chosen if it can represent | |
1975 | all the values of the unsigned type. */ | |
1976 | if (!TYPE_UNSIGNED (result_type)) | |
1977 | /* OK */; | |
1978 | /* Do not warn if both operands are unsigned. */ | |
1979 | else if (op0_signed == op1_signed) | |
1980 | /* OK */; | |
1981 | else | |
1982 | { | |
1983 | tree sop, uop, base_type; | |
1984 | bool ovf; | |
1985 | ||
1986 | if (op0_signed) | |
1987 | sop = orig_op0, uop = orig_op1; | |
1988 | else | |
1989 | sop = orig_op1, uop = orig_op0; | |
1990 | ||
1991 | STRIP_TYPE_NOPS (sop); | |
1992 | STRIP_TYPE_NOPS (uop); | |
1993 | base_type = (TREE_CODE (result_type) == COMPLEX_TYPE | |
1994 | ? TREE_TYPE (result_type) : result_type); | |
1995 | ||
1996 | /* Do not warn if the signed quantity is an unsuffixed integer | |
1997 | literal (or some static constant expression involving such | |
1998 | literals or a conditional expression involving such literals) | |
1999 | and it is non-negative. */ | |
2000 | if (tree_expr_nonnegative_warnv_p (sop, &ovf)) | |
2001 | /* OK */; | |
2002 | /* Do not warn if the comparison is an equality operation, the | |
2003 | unsigned quantity is an integral constant, and it would fit | |
2004 | in the result if the result were signed. */ | |
2005 | else if (TREE_CODE (uop) == INTEGER_CST | |
2006 | && (resultcode == EQ_EXPR || resultcode == NE_EXPR) | |
2007 | && int_fits_type_p (uop, c_common_signed_type (base_type))) | |
2008 | /* OK */; | |
2009 | /* In C, do not warn if the unsigned quantity is an enumeration | |
2010 | constant and its maximum value would fit in the result if the | |
2011 | result were signed. */ | |
2012 | else if (!c_dialect_cxx() && TREE_CODE (uop) == INTEGER_CST | |
2013 | && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE | |
2014 | && int_fits_type_p (TYPE_MAX_VALUE (TREE_TYPE (uop)), | |
2015 | c_common_signed_type (base_type))) | |
2016 | /* OK */; | |
2017 | else | |
06bd22f6 MP |
2018 | warning_at (location, OPT_Wsign_compare, |
2019 | "comparison of integer expressions of different " | |
2020 | "signedness: %qT and %qT", TREE_TYPE (orig_op0), | |
2021 | TREE_TYPE (orig_op1)); | |
038b5cc0 MP |
2022 | } |
2023 | ||
2024 | /* Warn if two unsigned values are being compared in a size larger | |
2025 | than their original size, and one (and only one) is the result of | |
2026 | a `~' operator. This comparison will always fail. | |
2027 | ||
2028 | Also warn if one operand is a constant, and the constant does not | |
2029 | have all bits set that are set in the ~ operand when it is | |
2030 | extended. */ | |
2031 | ||
2032 | op0 = c_common_get_narrower (op0, &unsignedp0); | |
2033 | op1 = c_common_get_narrower (op1, &unsignedp1); | |
2034 | ||
2035 | if ((TREE_CODE (op0) == BIT_NOT_EXPR) | |
2036 | ^ (TREE_CODE (op1) == BIT_NOT_EXPR)) | |
2037 | { | |
2038 | if (TREE_CODE (op0) == BIT_NOT_EXPR) | |
2039 | op0 = c_common_get_narrower (TREE_OPERAND (op0, 0), &unsignedp0); | |
2040 | if (TREE_CODE (op1) == BIT_NOT_EXPR) | |
2041 | op1 = c_common_get_narrower (TREE_OPERAND (op1, 0), &unsignedp1); | |
2042 | ||
2043 | if (tree_fits_shwi_p (op0) || tree_fits_shwi_p (op1)) | |
2044 | { | |
2045 | tree primop; | |
2046 | HOST_WIDE_INT constant, mask; | |
2047 | int unsignedp; | |
2048 | unsigned int bits; | |
2049 | ||
2050 | if (tree_fits_shwi_p (op0)) | |
2051 | { | |
2052 | primop = op1; | |
2053 | unsignedp = unsignedp1; | |
2054 | constant = tree_to_shwi (op0); | |
2055 | } | |
2056 | else | |
2057 | { | |
2058 | primop = op0; | |
2059 | unsignedp = unsignedp0; | |
2060 | constant = tree_to_shwi (op1); | |
2061 | } | |
2062 | ||
2063 | bits = TYPE_PRECISION (TREE_TYPE (primop)); | |
2064 | if (bits < TYPE_PRECISION (result_type) | |
2065 | && bits < HOST_BITS_PER_LONG && unsignedp) | |
2066 | { | |
2067 | mask = HOST_WIDE_INT_M1U << bits; | |
2068 | if ((mask & constant) != mask) | |
2069 | { | |
2070 | if (constant == 0) | |
2071 | warning_at (location, OPT_Wsign_compare, | |
2072 | "promoted ~unsigned is always non-zero"); | |
2073 | else | |
2074 | warning_at (location, OPT_Wsign_compare, | |
2075 | "comparison of promoted ~unsigned with constant"); | |
2076 | } | |
2077 | } | |
2078 | } | |
2079 | else if (unsignedp0 && unsignedp1 | |
2080 | && (TYPE_PRECISION (TREE_TYPE (op0)) | |
2081 | < TYPE_PRECISION (result_type)) | |
2082 | && (TYPE_PRECISION (TREE_TYPE (op1)) | |
2083 | < TYPE_PRECISION (result_type))) | |
2084 | warning_at (location, OPT_Wsign_compare, | |
2085 | "comparison of promoted ~unsigned with unsigned"); | |
2086 | } | |
2087 | } | |
2088 | ||
2089 | /* RESULT_TYPE is the result of converting TYPE1 and TYPE2 to a common | |
2090 | type via c_common_type. If -Wdouble-promotion is in use, and the | |
2091 | conditions for warning have been met, issue a warning. GMSGID is | |
2092 | the warning message. It must have two %T specifiers for the type | |
2093 | that was converted (generally "float") and the type to which it was | |
2094 | converted (generally "double), respectively. LOC is the location | |
5764ee3c | 2095 | to which the warning should refer. */ |
038b5cc0 MP |
2096 | |
2097 | void | |
2098 | do_warn_double_promotion (tree result_type, tree type1, tree type2, | |
2099 | const char *gmsgid, location_t loc) | |
2100 | { | |
2101 | tree source_type; | |
2102 | ||
2103 | if (!warn_double_promotion) | |
2104 | return; | |
2105 | /* If the conversion will not occur at run-time, there is no need to | |
2106 | warn about it. */ | |
2107 | if (c_inhibit_evaluation_warnings) | |
2108 | return; | |
c7545f1c MP |
2109 | /* If an invalid conversion has occured, don't warn. */ |
2110 | if (result_type == error_mark_node) | |
2111 | return; | |
038b5cc0 MP |
2112 | if (TYPE_MAIN_VARIANT (result_type) != double_type_node |
2113 | && TYPE_MAIN_VARIANT (result_type) != complex_double_type_node) | |
2114 | return; | |
2115 | if (TYPE_MAIN_VARIANT (type1) == float_type_node | |
2116 | || TYPE_MAIN_VARIANT (type1) == complex_float_type_node) | |
2117 | source_type = type1; | |
2118 | else if (TYPE_MAIN_VARIANT (type2) == float_type_node | |
2119 | || TYPE_MAIN_VARIANT (type2) == complex_float_type_node) | |
2120 | source_type = type2; | |
2121 | else | |
2122 | return; | |
2123 | warning_at (loc, OPT_Wdouble_promotion, gmsgid, source_type, result_type); | |
2124 | } | |
2125 | ||
2126 | /* Possibly warn about unused parameters. */ | |
2127 | ||
2128 | void | |
2129 | do_warn_unused_parameter (tree fn) | |
2130 | { | |
2131 | tree decl; | |
2132 | ||
2133 | for (decl = DECL_ARGUMENTS (fn); | |
2134 | decl; decl = DECL_CHAIN (decl)) | |
2135 | if (!TREE_USED (decl) && TREE_CODE (decl) == PARM_DECL | |
2136 | && DECL_NAME (decl) && !DECL_ARTIFICIAL (decl) | |
2137 | && !TREE_NO_WARNING (decl)) | |
2138 | warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wunused_parameter, | |
2139 | "unused parameter %qD", decl); | |
2140 | } | |
2141 | ||
2142 | /* If DECL is a typedef that is declared in the current function, | |
2143 | record it for the purpose of -Wunused-local-typedefs. */ | |
2144 | ||
2145 | void | |
2146 | record_locally_defined_typedef (tree decl) | |
2147 | { | |
2148 | struct c_language_function *l; | |
2149 | ||
2150 | if (!warn_unused_local_typedefs | |
2151 | || cfun == NULL | |
2152 | /* if this is not a locally defined typedef then we are not | |
2153 | interested. */ | |
2154 | || !is_typedef_decl (decl) | |
2155 | || !decl_function_context (decl)) | |
2156 | return; | |
2157 | ||
2158 | l = (struct c_language_function *) cfun->language; | |
2159 | vec_safe_push (l->local_typedefs, decl); | |
2160 | } | |
2161 | ||
2162 | /* If T is a TYPE_DECL declared locally, mark it as used. */ | |
2163 | ||
2164 | void | |
2165 | maybe_record_typedef_use (tree t) | |
2166 | { | |
2167 | if (!is_typedef_decl (t)) | |
2168 | return; | |
2169 | ||
2170 | TREE_USED (t) = true; | |
2171 | } | |
2172 | ||
2173 | /* Warn if there are some unused locally defined typedefs in the | |
2174 | current function. */ | |
2175 | ||
2176 | void | |
2177 | maybe_warn_unused_local_typedefs (void) | |
2178 | { | |
2179 | int i; | |
2180 | tree decl; | |
2181 | /* The number of times we have emitted -Wunused-local-typedefs | |
2182 | warnings. If this is different from errorcount, that means some | |
2183 | unrelated errors have been issued. In which case, we'll avoid | |
2184 | emitting "unused-local-typedefs" warnings. */ | |
2185 | static int unused_local_typedefs_warn_count; | |
2186 | struct c_language_function *l; | |
2187 | ||
2188 | if (cfun == NULL) | |
2189 | return; | |
2190 | ||
2191 | if ((l = (struct c_language_function *) cfun->language) == NULL) | |
2192 | return; | |
2193 | ||
2194 | if (warn_unused_local_typedefs | |
2195 | && errorcount == unused_local_typedefs_warn_count) | |
2196 | { | |
2197 | FOR_EACH_VEC_SAFE_ELT (l->local_typedefs, i, decl) | |
2198 | if (!TREE_USED (decl)) | |
2199 | warning_at (DECL_SOURCE_LOCATION (decl), | |
2200 | OPT_Wunused_local_typedefs, | |
2201 | "typedef %qD locally defined but not used", decl); | |
2202 | unused_local_typedefs_warn_count = errorcount; | |
2203 | } | |
2204 | ||
2205 | vec_free (l->local_typedefs); | |
2206 | } | |
2207 | ||
2208 | /* If we're creating an if-else-if condition chain, first see if we | |
2209 | already have this COND in the CHAIN. If so, warn and don't add COND | |
2210 | into the vector, otherwise add the COND there. LOC is the location | |
2211 | of COND. */ | |
2212 | ||
2213 | void | |
2214 | warn_duplicated_cond_add_or_warn (location_t loc, tree cond, vec<tree> **chain) | |
2215 | { | |
2216 | /* No chain has been created yet. Do nothing. */ | |
2217 | if (*chain == NULL) | |
2218 | return; | |
2219 | ||
2220 | if (TREE_SIDE_EFFECTS (cond)) | |
2221 | { | |
2222 | /* Uh-oh! This condition has a side-effect, thus invalidates | |
2223 | the whole chain. */ | |
2224 | delete *chain; | |
2225 | *chain = NULL; | |
2226 | return; | |
2227 | } | |
2228 | ||
2229 | unsigned int ix; | |
2230 | tree t; | |
2231 | bool found = false; | |
2232 | FOR_EACH_VEC_ELT (**chain, ix, t) | |
2233 | if (operand_equal_p (cond, t, 0)) | |
2234 | { | |
2235 | if (warning_at (loc, OPT_Wduplicated_cond, | |
2236 | "duplicated %<if%> condition")) | |
2237 | inform (EXPR_LOCATION (t), "previously used here"); | |
2238 | found = true; | |
2239 | break; | |
2240 | } | |
2241 | ||
2242 | if (!found | |
2243 | && !CONSTANT_CLASS_P (cond) | |
2244 | /* Don't infinitely grow the chain. */ | |
2245 | && (*chain)->length () < 512) | |
2246 | (*chain)->safe_push (cond); | |
2247 | } | |
2248 | ||
2249 | /* Check and possibly warn if two declarations have contradictory | |
2250 | attributes, such as always_inline vs. noinline. */ | |
2251 | ||
2252 | bool | |
2253 | diagnose_mismatched_attributes (tree olddecl, tree newdecl) | |
2254 | { | |
2255 | bool warned = false; | |
2256 | ||
2257 | tree a1 = lookup_attribute ("optimize", DECL_ATTRIBUTES (olddecl)); | |
2258 | tree a2 = lookup_attribute ("optimize", DECL_ATTRIBUTES (newdecl)); | |
2259 | /* An optimization attribute applied on a declaration after the | |
2260 | definition is likely not what the user wanted. */ | |
2261 | if (a2 != NULL_TREE | |
2262 | && DECL_SAVED_TREE (olddecl) != NULL_TREE | |
2263 | && (a1 == NULL_TREE || !attribute_list_equal (a1, a2))) | |
2264 | warned |= warning (OPT_Wattributes, | |
2265 | "optimization attribute on %qD follows " | |
2266 | "definition but the attribute doesn%'t match", | |
2267 | newdecl); | |
2268 | ||
2269 | /* Diagnose inline __attribute__ ((noinline)) which is silly. */ | |
2270 | if (DECL_DECLARED_INLINE_P (newdecl) | |
2271 | && DECL_UNINLINABLE (olddecl) | |
44284983 | 2272 | && lookup_attribute ("noinline", DECL_ATTRIBUTES (olddecl))) |
038b5cc0 | 2273 | warned |= warning (OPT_Wattributes, "inline declaration of %qD follows " |
44284983 | 2274 | "declaration with attribute %<noinline%>", newdecl); |
038b5cc0 MP |
2275 | else if (DECL_DECLARED_INLINE_P (olddecl) |
2276 | && DECL_UNINLINABLE (newdecl) | |
2277 | && lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl))) | |
2278 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
44284983 | 2279 | "%<noinline%> follows inline declaration", newdecl); |
5d9ae53d | 2280 | |
038b5cc0 MP |
2281 | return warned; |
2282 | } | |
2283 | ||
2284 | /* Warn if signed left shift overflows. We don't warn | |
2285 | about left-shifting 1 into the sign bit in C++14; cf. | |
2286 | <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3367.html#1457> | |
2287 | LOC is a location of the shift; OP0 and OP1 are the operands. | |
2288 | Return true if an overflow is detected, false otherwise. */ | |
2289 | ||
2290 | bool | |
2291 | maybe_warn_shift_overflow (location_t loc, tree op0, tree op1) | |
2292 | { | |
2293 | if (TREE_CODE (op0) != INTEGER_CST | |
2294 | || TREE_CODE (op1) != INTEGER_CST) | |
2295 | return false; | |
2296 | ||
2297 | tree type0 = TREE_TYPE (op0); | |
2298 | unsigned int prec0 = TYPE_PRECISION (type0); | |
2299 | ||
2300 | /* Left-hand operand must be signed. */ | |
2301 | if (TYPE_UNSIGNED (type0)) | |
2302 | return false; | |
2303 | ||
8e6cdc90 | 2304 | unsigned int min_prec = (wi::min_precision (wi::to_wide (op0), SIGNED) |
038b5cc0 MP |
2305 | + TREE_INT_CST_LOW (op1)); |
2306 | /* Handle the case of left-shifting 1 into the sign bit. | |
2307 | * However, shifting 1 _out_ of the sign bit, as in | |
2308 | * INT_MIN << 1, is considered an overflow. | |
2309 | */ | |
2310 | if (!tree_int_cst_sign_bit(op0) && min_prec == prec0 + 1) | |
2311 | { | |
2312 | /* Never warn for C++14 onwards. */ | |
2313 | if (cxx_dialect >= cxx14) | |
2314 | return false; | |
2315 | /* Otherwise only if -Wshift-overflow=2. But return | |
2316 | true to signal an overflow for the sake of integer | |
2317 | constant expressions. */ | |
2318 | if (warn_shift_overflow < 2) | |
2319 | return true; | |
2320 | } | |
2321 | ||
2322 | bool overflowed = min_prec > prec0; | |
2323 | if (overflowed && c_inhibit_evaluation_warnings == 0) | |
2324 | warning_at (loc, OPT_Wshift_overflow_, | |
2325 | "result of %qE requires %u bits to represent, " | |
2326 | "but %qT only has %u bits", | |
2327 | build2_loc (loc, LSHIFT_EXPR, type0, op0, op1), | |
2328 | min_prec, type0, prec0); | |
2329 | ||
2330 | return overflowed; | |
2331 | } | |
2332 | ||
2333 | /* Warn about boolean expression compared with an integer value different | |
2334 | from true/false. Warns also e.g. about "(i1 == i2) == 2". | |
2335 | LOC is the location of the comparison, CODE is its code, OP0 and OP1 | |
2336 | are the operands of the comparison. The caller must ensure that | |
2337 | either operand is a boolean expression. */ | |
2338 | ||
2339 | void | |
2340 | maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0, | |
2341 | tree op1) | |
2342 | { | |
2343 | if (TREE_CODE_CLASS (code) != tcc_comparison) | |
2344 | return; | |
2345 | ||
2346 | tree f, cst; | |
2347 | if (f = fold_for_warn (op0), | |
2348 | TREE_CODE (f) == INTEGER_CST) | |
2349 | cst = op0 = f; | |
2350 | else if (f = fold_for_warn (op1), | |
2351 | TREE_CODE (f) == INTEGER_CST) | |
2352 | cst = op1 = f; | |
2353 | else | |
2354 | return; | |
2355 | ||
2356 | if (!integer_zerop (cst) && !integer_onep (cst)) | |
2357 | { | |
2358 | int sign = (TREE_CODE (op0) == INTEGER_CST | |
2359 | ? tree_int_cst_sgn (cst) : -tree_int_cst_sgn (cst)); | |
2360 | if (code == EQ_EXPR | |
2361 | || ((code == GT_EXPR || code == GE_EXPR) && sign < 0) | |
2362 | || ((code == LT_EXPR || code == LE_EXPR) && sign > 0)) | |
2363 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2364 | "with boolean expression is always false", cst); | |
2365 | else | |
2366 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2367 | "with boolean expression is always true", cst); | |
2368 | } | |
2369 | else if (integer_zerop (cst) || integer_onep (cst)) | |
2370 | { | |
2371 | /* If the non-constant operand isn't of a boolean type, we | |
2372 | don't want to warn here. */ | |
2373 | tree noncst = TREE_CODE (op0) == INTEGER_CST ? op1 : op0; | |
2374 | /* Handle booleans promoted to integers. */ | |
2375 | if (bool_promoted_to_int_p (noncst)) | |
2376 | /* Warn. */; | |
2377 | else if (TREE_CODE (TREE_TYPE (noncst)) != BOOLEAN_TYPE | |
2378 | && !truth_value_p (TREE_CODE (noncst))) | |
2379 | return; | |
2380 | /* Do some magic to get the right diagnostics. */ | |
2381 | bool flag = TREE_CODE (op0) == INTEGER_CST; | |
2382 | flag = integer_zerop (cst) ? flag : !flag; | |
2383 | if ((code == GE_EXPR && !flag) || (code == LE_EXPR && flag)) | |
2384 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2385 | "with boolean expression is always true", cst); | |
2386 | else if ((code == LT_EXPR && !flag) || (code == GT_EXPR && flag)) | |
2387 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2388 | "with boolean expression is always false", cst); | |
2389 | } | |
2390 | } | |
975672f3 PK |
2391 | |
2392 | /* Warn if an argument at position param_pos is passed to a | |
e9b9fa4c MS |
2393 | restrict-qualified param, and it aliases with another argument. |
2394 | Return true if a warning has been issued. */ | |
975672f3 | 2395 | |
e9b9fa4c | 2396 | bool |
4227c9ad | 2397 | warn_for_restrict (unsigned param_pos, tree *argarray, unsigned nargs) |
975672f3 | 2398 | { |
4227c9ad JJ |
2399 | tree arg = argarray[param_pos]; |
2400 | if (TREE_VISITED (arg) || integer_zerop (arg)) | |
e9b9fa4c | 2401 | return false; |
975672f3 PK |
2402 | |
2403 | location_t loc = EXPR_LOC_OR_LOC (arg, input_location); | |
2404 | gcc_rich_location richloc (loc); | |
2405 | ||
2406 | unsigned i; | |
4227c9ad | 2407 | auto_vec<int, 16> arg_positions; |
975672f3 | 2408 | |
4227c9ad | 2409 | for (i = 0; i < nargs; i++) |
975672f3 PK |
2410 | { |
2411 | if (i == param_pos) | |
2412 | continue; | |
2413 | ||
4227c9ad | 2414 | tree current_arg = argarray[i]; |
975672f3 PK |
2415 | if (operand_equal_p (arg, current_arg, 0)) |
2416 | { | |
e9b9fa4c | 2417 | TREE_VISITED (current_arg) = 1; |
4227c9ad | 2418 | arg_positions.safe_push (i + 1); |
975672f3 PK |
2419 | } |
2420 | } | |
2421 | ||
4227c9ad | 2422 | if (arg_positions.is_empty ()) |
e9b9fa4c | 2423 | return false; |
975672f3 | 2424 | |
4227c9ad JJ |
2425 | int pos; |
2426 | FOR_EACH_VEC_ELT (arg_positions, i, pos) | |
975672f3 | 2427 | { |
4227c9ad | 2428 | arg = argarray[pos - 1]; |
975672f3 PK |
2429 | if (EXPR_HAS_LOCATION (arg)) |
2430 | richloc.add_range (EXPR_LOCATION (arg), false); | |
2431 | } | |
2432 | ||
e9b9fa4c MS |
2433 | return warning_n (&richloc, OPT_Wrestrict, arg_positions.length (), |
2434 | "passing argument %i to restrict-qualified parameter" | |
2435 | " aliases with argument %Z", | |
2436 | "passing argument %i to restrict-qualified parameter" | |
2437 | " aliases with arguments %Z", | |
2438 | param_pos + 1, arg_positions.address (), | |
2439 | arg_positions.length ()); | |
975672f3 | 2440 | } |
2ebd93e1 MP |
2441 | |
2442 | /* Callback function to determine whether an expression TP or one of its | |
2443 | subexpressions comes from macro expansion. Used to suppress bogus | |
2444 | warnings. */ | |
2445 | ||
2446 | static tree | |
2447 | expr_from_macro_expansion_r (tree *tp, int *, void *) | |
2448 | { | |
2449 | if (CAN_HAVE_LOCATION_P (*tp) | |
2450 | && from_macro_expansion_at (EXPR_LOCATION (*tp))) | |
2451 | return integer_zero_node; | |
2452 | ||
2453 | return NULL_TREE; | |
2454 | } | |
2455 | ||
2456 | /* Possibly warn when an if-else has identical branches. */ | |
2457 | ||
2458 | static void | |
2459 | do_warn_duplicated_branches (tree expr) | |
2460 | { | |
2461 | tree thenb = COND_EXPR_THEN (expr); | |
2462 | tree elseb = COND_EXPR_ELSE (expr); | |
2463 | ||
8a516588 MP |
2464 | /* Don't bother if any of the branches is missing. */ |
2465 | if (thenb == NULL_TREE || elseb == NULL_TREE) | |
2ebd93e1 MP |
2466 | return; |
2467 | ||
2468 | /* And don't warn for empty statements. */ | |
2469 | if (TREE_CODE (thenb) == NOP_EXPR | |
2470 | && TREE_TYPE (thenb) == void_type_node | |
2471 | && TREE_OPERAND (thenb, 0) == size_zero_node) | |
2472 | return; | |
2473 | ||
2474 | /* ... or empty branches. */ | |
2475 | if (TREE_CODE (thenb) == STATEMENT_LIST | |
2476 | && STATEMENT_LIST_HEAD (thenb) == NULL) | |
2477 | return; | |
2478 | ||
2479 | /* Compute the hash of the then branch. */ | |
2480 | inchash::hash hstate0 (0); | |
2481 | inchash::add_expr (thenb, hstate0); | |
2482 | hashval_t h0 = hstate0.end (); | |
2483 | ||
2484 | /* Compute the hash of the else branch. */ | |
2485 | inchash::hash hstate1 (0); | |
2486 | inchash::add_expr (elseb, hstate1); | |
2487 | hashval_t h1 = hstate1.end (); | |
2488 | ||
2489 | /* Compare the hashes. */ | |
2490 | if (h0 == h1 | |
2491 | && operand_equal_p (thenb, elseb, OEP_LEXICOGRAPHIC) | |
2492 | /* Don't warn if any of the branches or their subexpressions comes | |
2493 | from a macro. */ | |
2494 | && !walk_tree_without_duplicates (&thenb, expr_from_macro_expansion_r, | |
2495 | NULL) | |
2496 | && !walk_tree_without_duplicates (&elseb, expr_from_macro_expansion_r, | |
2497 | NULL)) | |
2498 | warning_at (EXPR_LOCATION (expr), OPT_Wduplicated_branches, | |
2499 | "this condition has identical branches"); | |
2500 | } | |
2501 | ||
2502 | /* Callback for c_genericize to implement -Wduplicated-branches. */ | |
2503 | ||
2504 | tree | |
2505 | do_warn_duplicated_branches_r (tree *tp, int *, void *) | |
2506 | { | |
2507 | if (TREE_CODE (*tp) == COND_EXPR) | |
2508 | do_warn_duplicated_branches (*tp); | |
2509 | return NULL_TREE; | |
2510 | } | |
3e2becc4 MP |
2511 | |
2512 | /* Implementation of -Wmultistatement-macros. This warning warns about | |
2513 | cases when a macro expands to multiple statements not wrapped in | |
2514 | do {} while (0) or ({ }) and is used as a body of if/else/for/while | |
2515 | conditionals. For example, | |
2516 | ||
2517 | #define DOIT x++; y++ | |
2518 | ||
2519 | if (c) | |
2520 | DOIT; | |
2521 | ||
2522 | will increment y unconditionally. | |
2523 | ||
2524 | BODY_LOC is the location of the first token in the body after labels | |
2525 | have been parsed, NEXT_LOC is the location of the next token after the | |
2526 | body of the conditional has been parsed, and GUARD_LOC is the location | |
2527 | of the conditional. */ | |
2528 | ||
2529 | void | |
2530 | warn_for_multistatement_macros (location_t body_loc, location_t next_loc, | |
2531 | location_t guard_loc, enum rid keyword) | |
2532 | { | |
2533 | if (!warn_multistatement_macros) | |
2534 | return; | |
2535 | ||
2536 | /* Ain't got time to waste. We only care about macros here. */ | |
2537 | if (!from_macro_expansion_at (body_loc) | |
2538 | || !from_macro_expansion_at (next_loc)) | |
2539 | return; | |
2540 | ||
2541 | /* Let's skip macros defined in system headers. */ | |
2542 | if (in_system_header_at (body_loc) | |
2543 | || in_system_header_at (next_loc)) | |
2544 | return; | |
2545 | ||
2546 | /* Find the actual tokens in the macro definition. BODY_LOC and | |
2547 | NEXT_LOC have to come from the same spelling location, but they | |
2548 | will resolve to different locations in the context of the macro | |
2549 | definition. */ | |
2550 | location_t body_loc_exp | |
2551 | = linemap_resolve_location (line_table, body_loc, | |
2552 | LRK_MACRO_DEFINITION_LOCATION, NULL); | |
2553 | location_t next_loc_exp | |
2554 | = linemap_resolve_location (line_table, next_loc, | |
2555 | LRK_MACRO_DEFINITION_LOCATION, NULL); | |
2556 | location_t guard_loc_exp | |
2557 | = linemap_resolve_location (line_table, guard_loc, | |
2558 | LRK_MACRO_DEFINITION_LOCATION, NULL); | |
2559 | ||
2560 | /* These are some funky cases we don't want to warn about. */ | |
2561 | if (body_loc_exp == guard_loc_exp | |
2562 | || next_loc_exp == guard_loc_exp | |
2563 | || body_loc_exp == next_loc_exp) | |
2564 | return; | |
2565 | ||
8a6eab34 MP |
2566 | /* Find the macro maps for the macro expansions. */ |
2567 | const line_map *body_map = linemap_lookup (line_table, body_loc); | |
2568 | const line_map *next_map = linemap_lookup (line_table, next_loc); | |
2569 | const line_map *guard_map = linemap_lookup (line_table, guard_loc); | |
2570 | ||
2571 | /* Now see if the following token (after the body) is coming from the | |
2572 | same macro expansion. If it is, it might be a problem. */ | |
2573 | if (body_map != next_map) | |
2574 | return; | |
3e2becc4 MP |
2575 | |
2576 | /* The conditional itself must not come from the same expansion, because | |
2577 | we don't want to warn about | |
2578 | #define IF if (x) x++; y++ | |
2579 | and similar. */ | |
8a6eab34 | 2580 | if (guard_map == body_map) |
3e2becc4 MP |
2581 | return; |
2582 | ||
8a6eab34 MP |
2583 | /* Handle the case where NEXT and BODY come from the same expansion while |
2584 | GUARD doesn't, yet we shouldn't warn. E.g. | |
2585 | ||
2586 | #define GUARD if (...) | |
2587 | #define GUARD2 GUARD | |
2588 | ||
2589 | and in the definition of another macro: | |
2590 | ||
2591 | GUARD2 | |
2592 | foo (); | |
2593 | return 1; | |
2594 | */ | |
2595 | while (linemap_macro_expansion_map_p (guard_map)) | |
2596 | { | |
2597 | const line_map_macro *mm = linemap_check_macro (guard_map); | |
2598 | guard_loc_exp = MACRO_MAP_EXPANSION_POINT_LOCATION (mm); | |
2599 | guard_map = linemap_lookup (line_table, guard_loc_exp); | |
2600 | if (guard_map == body_map) | |
2601 | return; | |
2602 | } | |
2603 | ||
3e2becc4 MP |
2604 | if (warning_at (body_loc, OPT_Wmultistatement_macros, |
2605 | "macro expands to multiple statements")) | |
2606 | inform (guard_loc, "some parts of macro expansion are not guarded by " | |
2607 | "this %qs clause", guard_tinfo_to_string (keyword)); | |
2608 | } |