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038b5cc0 MP |
1 | /* Diagnostic routines shared by all languages that are variants of C. |
2 | Copyright (C) 1992-2016 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 3, or (at your option) any later | |
9 | version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING3. If not see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "config.h" | |
21 | #include "system.h" | |
22 | #include "coretypes.h" | |
23 | #include "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" | |
31 | ||
32 | ||
33 | /* Print a warning if a constant expression had overflow in folding. | |
34 | Invoke this function on every expression that the language | |
35 | requires to be a constant expression. | |
36 | Note the ANSI C standard says it is erroneous for a | |
37 | constant expression to overflow. */ | |
38 | ||
39 | void | |
40 | constant_expression_warning (tree value) | |
41 | { | |
42 | if (warn_overflow && pedantic | |
43 | && (TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST | |
44 | || TREE_CODE (value) == FIXED_CST | |
45 | || TREE_CODE (value) == VECTOR_CST | |
46 | || TREE_CODE (value) == COMPLEX_CST) | |
47 | && TREE_OVERFLOW (value)) | |
48 | pedwarn (input_location, OPT_Woverflow, "overflow in constant expression"); | |
49 | } | |
50 | ||
51 | /* The same as above but print an unconditional error. */ | |
52 | ||
53 | void | |
54 | constant_expression_error (tree value) | |
55 | { | |
56 | if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST | |
57 | || TREE_CODE (value) == FIXED_CST | |
58 | || TREE_CODE (value) == VECTOR_CST | |
59 | || TREE_CODE (value) == COMPLEX_CST) | |
60 | && TREE_OVERFLOW (value)) | |
61 | error ("overflow in constant expression"); | |
62 | } | |
63 | ||
64 | /* Print a warning if an expression had overflow in folding and its | |
65 | operands hadn't. | |
66 | ||
67 | Invoke this function on every expression that | |
68 | (1) appears in the source code, and | |
69 | (2) is a constant expression that overflowed, and | |
70 | (3) is not already checked by convert_and_check; | |
71 | however, do not invoke this function on operands of explicit casts | |
72 | or when the expression is the result of an operator and any operand | |
73 | already overflowed. */ | |
74 | ||
75 | void | |
76 | overflow_warning (location_t loc, tree value) | |
77 | { | |
78 | if (c_inhibit_evaluation_warnings != 0) | |
79 | return; | |
80 | ||
81 | switch (TREE_CODE (value)) | |
82 | { | |
83 | case INTEGER_CST: | |
84 | warning_at (loc, OPT_Woverflow, "integer overflow in expression"); | |
85 | break; | |
86 | ||
87 | case REAL_CST: | |
88 | warning_at (loc, OPT_Woverflow, | |
89 | "floating point overflow in expression"); | |
90 | break; | |
91 | ||
92 | case FIXED_CST: | |
93 | warning_at (loc, OPT_Woverflow, "fixed-point overflow in expression"); | |
94 | break; | |
95 | ||
96 | case VECTOR_CST: | |
97 | warning_at (loc, OPT_Woverflow, "vector overflow in expression"); | |
98 | break; | |
99 | ||
100 | case COMPLEX_CST: | |
101 | if (TREE_CODE (TREE_REALPART (value)) == INTEGER_CST) | |
102 | warning_at (loc, OPT_Woverflow, | |
103 | "complex integer overflow in expression"); | |
104 | else if (TREE_CODE (TREE_REALPART (value)) == REAL_CST) | |
105 | warning_at (loc, OPT_Woverflow, | |
106 | "complex floating point overflow in expression"); | |
107 | break; | |
108 | ||
109 | default: | |
110 | break; | |
111 | } | |
112 | } | |
113 | ||
114 | /* Warn about uses of logical || / && operator in a context where it | |
115 | is likely that the bitwise equivalent was intended by the | |
116 | programmer. We have seen an expression in which CODE is a binary | |
117 | operator used to combine expressions OP_LEFT and OP_RIGHT, which before folding | |
118 | had CODE_LEFT and CODE_RIGHT, into an expression of type TYPE. */ | |
119 | ||
120 | void | |
121 | warn_logical_operator (location_t location, enum tree_code code, tree type, | |
122 | enum tree_code code_left, tree op_left, | |
123 | enum tree_code ARG_UNUSED (code_right), tree op_right) | |
124 | { | |
125 | int or_op = (code == TRUTH_ORIF_EXPR || code == TRUTH_OR_EXPR); | |
126 | int in0_p, in1_p, in_p; | |
127 | tree low0, low1, low, high0, high1, high, lhs, rhs, tem; | |
128 | bool strict_overflow_p = false; | |
129 | ||
130 | if (code != TRUTH_ANDIF_EXPR | |
131 | && code != TRUTH_AND_EXPR | |
132 | && code != TRUTH_ORIF_EXPR | |
133 | && code != TRUTH_OR_EXPR) | |
134 | return; | |
135 | ||
136 | /* We don't want to warn if either operand comes from a macro | |
137 | expansion. ??? This doesn't work with e.g. NEGATE_EXPR yet; | |
138 | see PR61534. */ | |
139 | if (from_macro_expansion_at (EXPR_LOCATION (op_left)) | |
140 | || from_macro_expansion_at (EXPR_LOCATION (op_right))) | |
141 | return; | |
142 | ||
143 | /* Warn if &&/|| are being used in a context where it is | |
144 | likely that the bitwise equivalent was intended by the | |
145 | programmer. That is, an expression such as op && MASK | |
146 | where op should not be any boolean expression, nor a | |
147 | constant, and mask seems to be a non-boolean integer constant. */ | |
148 | if (TREE_CODE (op_right) == CONST_DECL) | |
149 | /* An enumerator counts as a constant. */ | |
150 | op_right = DECL_INITIAL (op_right); | |
151 | if (!truth_value_p (code_left) | |
152 | && INTEGRAL_TYPE_P (TREE_TYPE (op_left)) | |
153 | && !CONSTANT_CLASS_P (op_left) | |
154 | && !TREE_NO_WARNING (op_left) | |
155 | && TREE_CODE (op_right) == INTEGER_CST | |
156 | && !integer_zerop (op_right) | |
157 | && !integer_onep (op_right)) | |
158 | { | |
159 | if (or_op) | |
160 | warning_at (location, OPT_Wlogical_op, "logical %<or%>" | |
161 | " applied to non-boolean constant"); | |
162 | else | |
163 | warning_at (location, OPT_Wlogical_op, "logical %<and%>" | |
164 | " applied to non-boolean constant"); | |
165 | TREE_NO_WARNING (op_left) = true; | |
166 | return; | |
167 | } | |
168 | ||
169 | /* We do not warn for constants because they are typical of macro | |
170 | expansions that test for features. */ | |
171 | if (CONSTANT_CLASS_P (fold_for_warn (op_left)) | |
172 | || CONSTANT_CLASS_P (fold_for_warn (op_right))) | |
173 | return; | |
174 | ||
175 | /* This warning only makes sense with logical operands. */ | |
176 | if (!(truth_value_p (TREE_CODE (op_left)) | |
177 | || INTEGRAL_TYPE_P (TREE_TYPE (op_left))) | |
178 | || !(truth_value_p (TREE_CODE (op_right)) | |
179 | || INTEGRAL_TYPE_P (TREE_TYPE (op_right)))) | |
180 | return; | |
181 | ||
182 | /* The range computations only work with scalars. */ | |
183 | if (VECTOR_TYPE_P (TREE_TYPE (op_left)) | |
184 | || VECTOR_TYPE_P (TREE_TYPE (op_right))) | |
185 | return; | |
186 | ||
187 | /* We first test whether either side separately is trivially true | |
188 | (with OR) or trivially false (with AND). If so, do not warn. | |
189 | This is a common idiom for testing ranges of data types in | |
190 | portable code. */ | |
191 | lhs = make_range (op_left, &in0_p, &low0, &high0, &strict_overflow_p); | |
192 | if (!lhs) | |
193 | return; | |
194 | if (TREE_CODE (lhs) == C_MAYBE_CONST_EXPR) | |
195 | lhs = C_MAYBE_CONST_EXPR_EXPR (lhs); | |
196 | ||
197 | /* If this is an OR operation, invert both sides; now, the result | |
198 | should be always false to get a warning. */ | |
199 | if (or_op) | |
200 | in0_p = !in0_p; | |
201 | ||
202 | tem = build_range_check (UNKNOWN_LOCATION, type, lhs, in0_p, low0, high0); | |
203 | if (tem && integer_zerop (tem)) | |
204 | return; | |
205 | ||
206 | rhs = make_range (op_right, &in1_p, &low1, &high1, &strict_overflow_p); | |
207 | if (!rhs) | |
208 | return; | |
209 | if (TREE_CODE (rhs) == C_MAYBE_CONST_EXPR) | |
210 | rhs = C_MAYBE_CONST_EXPR_EXPR (rhs); | |
211 | ||
212 | /* If this is an OR operation, invert both sides; now, the result | |
213 | should be always false to get a warning. */ | |
214 | if (or_op) | |
215 | in1_p = !in1_p; | |
216 | ||
217 | tem = build_range_check (UNKNOWN_LOCATION, type, rhs, in1_p, low1, high1); | |
218 | if (tem && integer_zerop (tem)) | |
219 | return; | |
220 | ||
221 | /* If both expressions have the same operand, if we can merge the | |
222 | ranges, ... */ | |
223 | if (operand_equal_p (lhs, rhs, 0) | |
224 | && merge_ranges (&in_p, &low, &high, in0_p, low0, high0, | |
225 | in1_p, low1, high1)) | |
226 | { | |
227 | tem = build_range_check (UNKNOWN_LOCATION, type, lhs, in_p, low, high); | |
228 | /* ... and if the range test is always false, then warn. */ | |
229 | if (tem && integer_zerop (tem)) | |
230 | { | |
231 | if (or_op) | |
232 | warning_at (location, OPT_Wlogical_op, | |
233 | "logical %<or%> of collectively exhaustive tests is " | |
234 | "always true"); | |
235 | else | |
236 | warning_at (location, OPT_Wlogical_op, | |
237 | "logical %<and%> of mutually exclusive tests is " | |
238 | "always false"); | |
239 | } | |
240 | /* Or warn if the operands have exactly the same range, e.g. | |
241 | A > 0 && A > 0. */ | |
242 | else if (tree_int_cst_equal (low0, low1) | |
243 | && tree_int_cst_equal (high0, high1)) | |
244 | { | |
245 | if (or_op) | |
246 | warning_at (location, OPT_Wlogical_op, | |
247 | "logical %<or%> of equal expressions"); | |
248 | else | |
249 | warning_at (location, OPT_Wlogical_op, | |
250 | "logical %<and%> of equal expressions"); | |
251 | } | |
252 | } | |
253 | } | |
254 | ||
255 | /* Helper function for warn_tautological_cmp. Look for ARRAY_REFs | |
256 | with constant indices. */ | |
257 | ||
258 | static tree | |
259 | find_array_ref_with_const_idx_r (tree *expr_p, int *walk_subtrees, void *data) | |
260 | { | |
261 | tree expr = *expr_p; | |
262 | ||
263 | if ((TREE_CODE (expr) == ARRAY_REF | |
264 | || TREE_CODE (expr) == ARRAY_RANGE_REF) | |
265 | && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST) | |
266 | { | |
267 | *(bool *) data = true; | |
268 | *walk_subtrees = 0; | |
269 | } | |
270 | ||
271 | return NULL_TREE; | |
272 | } | |
273 | ||
274 | /* Warn if a self-comparison always evaluates to true or false. LOC | |
275 | is the location of the comparison with code CODE, LHS and RHS are | |
276 | operands of the comparison. */ | |
277 | ||
278 | void | |
279 | warn_tautological_cmp (location_t loc, enum tree_code code, tree lhs, tree rhs) | |
280 | { | |
281 | if (TREE_CODE_CLASS (code) != tcc_comparison) | |
282 | return; | |
283 | ||
284 | /* Don't warn for various macro expansions. */ | |
285 | if (from_macro_expansion_at (loc) | |
286 | || from_macro_expansion_at (EXPR_LOCATION (lhs)) | |
287 | || from_macro_expansion_at (EXPR_LOCATION (rhs))) | |
288 | return; | |
289 | ||
290 | /* We do not warn for constants because they are typical of macro | |
291 | expansions that test for features, sizeof, and similar. */ | |
292 | if (CONSTANT_CLASS_P (fold_for_warn (lhs)) | |
293 | || CONSTANT_CLASS_P (fold_for_warn (rhs))) | |
294 | return; | |
295 | ||
296 | /* Don't warn for e.g. | |
297 | HOST_WIDE_INT n; | |
298 | ... | |
299 | if (n == (long) n) ... | |
300 | */ | |
301 | if ((CONVERT_EXPR_P (lhs) || TREE_CODE (lhs) == NON_LVALUE_EXPR) | |
302 | || (CONVERT_EXPR_P (rhs) || TREE_CODE (rhs) == NON_LVALUE_EXPR)) | |
303 | return; | |
304 | ||
305 | /* Don't warn if either LHS or RHS has an IEEE floating-point type. | |
306 | It could be a NaN, and NaN never compares equal to anything, even | |
307 | itself. */ | |
308 | if (FLOAT_TYPE_P (TREE_TYPE (lhs)) || FLOAT_TYPE_P (TREE_TYPE (rhs))) | |
309 | return; | |
310 | ||
311 | if (operand_equal_p (lhs, rhs, 0)) | |
312 | { | |
313 | /* Don't warn about array references with constant indices; | |
314 | these are likely to come from a macro. */ | |
315 | bool found = false; | |
316 | walk_tree_without_duplicates (&lhs, find_array_ref_with_const_idx_r, | |
317 | &found); | |
318 | if (found) | |
319 | return; | |
320 | const bool always_true = (code == EQ_EXPR || code == LE_EXPR | |
321 | || code == GE_EXPR || code == UNLE_EXPR | |
322 | || code == UNGE_EXPR || code == UNEQ_EXPR); | |
323 | if (always_true) | |
324 | warning_at (loc, OPT_Wtautological_compare, | |
325 | "self-comparison always evaluates to true"); | |
326 | else | |
327 | warning_at (loc, OPT_Wtautological_compare, | |
328 | "self-comparison always evaluates to false"); | |
329 | } | |
330 | } | |
331 | ||
332 | /* Return true iff EXPR only contains boolean operands, or comparisons. */ | |
333 | ||
334 | static bool | |
335 | expr_has_boolean_operands_p (tree expr) | |
336 | { | |
337 | STRIP_NOPS (expr); | |
338 | ||
339 | if (CONVERT_EXPR_P (expr)) | |
340 | return bool_promoted_to_int_p (expr); | |
341 | else if (UNARY_CLASS_P (expr)) | |
342 | return expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)); | |
343 | else if (BINARY_CLASS_P (expr)) | |
344 | return (expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)) | |
345 | && expr_has_boolean_operands_p (TREE_OPERAND (expr, 1))); | |
346 | else if (COMPARISON_CLASS_P (expr)) | |
347 | return true; | |
348 | else | |
349 | return false; | |
350 | } | |
351 | ||
352 | /* Warn about logical not used on the left hand side operand of a comparison. | |
353 | This function assumes that the LHS is inside of TRUTH_NOT_EXPR. | |
354 | Do not warn if RHS is of a boolean type, a logical operator, or | |
355 | a comparison. */ | |
356 | ||
357 | void | |
358 | warn_logical_not_parentheses (location_t location, enum tree_code code, | |
359 | tree lhs, tree rhs) | |
360 | { | |
361 | if (TREE_CODE_CLASS (code) != tcc_comparison | |
362 | || TREE_TYPE (rhs) == NULL_TREE | |
363 | || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE | |
364 | || truth_value_p (TREE_CODE (rhs))) | |
365 | return; | |
366 | ||
367 | /* Don't warn for expression like !x == ~(bool1 | bool2). */ | |
368 | if (expr_has_boolean_operands_p (rhs)) | |
369 | return; | |
370 | ||
371 | /* Don't warn for !x == 0 or !y != 0, those are equivalent to | |
372 | !(x == 0) or !(y != 0). */ | |
373 | if ((code == EQ_EXPR || code == NE_EXPR) | |
374 | && integer_zerop (rhs)) | |
375 | return; | |
376 | ||
377 | if (warning_at (location, OPT_Wlogical_not_parentheses, | |
378 | "logical not is only applied to the left hand side of " | |
379 | "comparison") | |
380 | && EXPR_HAS_LOCATION (lhs)) | |
381 | { | |
382 | location_t lhs_loc = EXPR_LOCATION (lhs); | |
383 | rich_location richloc (line_table, lhs_loc); | |
384 | richloc.add_fixit_insert_before (lhs_loc, "("); | |
385 | richloc.add_fixit_insert_after (lhs_loc, ")"); | |
386 | inform_at_rich_loc (&richloc, "add parentheses around left hand side " | |
387 | "expression to silence this warning"); | |
388 | } | |
389 | } | |
390 | ||
391 | /* Warn if EXP contains any computations whose results are not used. | |
392 | Return true if a warning is printed; false otherwise. LOCUS is the | |
393 | (potential) location of the expression. */ | |
394 | ||
395 | bool | |
396 | warn_if_unused_value (const_tree exp, location_t locus) | |
397 | { | |
398 | restart: | |
399 | if (TREE_USED (exp) || TREE_NO_WARNING (exp)) | |
400 | return false; | |
401 | ||
402 | /* Don't warn about void constructs. This includes casting to void, | |
403 | void function calls, and statement expressions with a final cast | |
404 | to void. */ | |
405 | if (VOID_TYPE_P (TREE_TYPE (exp))) | |
406 | return false; | |
407 | ||
408 | if (EXPR_HAS_LOCATION (exp)) | |
409 | locus = EXPR_LOCATION (exp); | |
410 | ||
411 | switch (TREE_CODE (exp)) | |
412 | { | |
413 | case PREINCREMENT_EXPR: | |
414 | case POSTINCREMENT_EXPR: | |
415 | case PREDECREMENT_EXPR: | |
416 | case POSTDECREMENT_EXPR: | |
417 | case MODIFY_EXPR: | |
418 | case INIT_EXPR: | |
419 | case TARGET_EXPR: | |
420 | case CALL_EXPR: | |
421 | case TRY_CATCH_EXPR: | |
422 | case WITH_CLEANUP_EXPR: | |
423 | case EXIT_EXPR: | |
424 | case VA_ARG_EXPR: | |
425 | return false; | |
426 | ||
427 | case BIND_EXPR: | |
428 | /* For a binding, warn if no side effect within it. */ | |
429 | exp = BIND_EXPR_BODY (exp); | |
430 | goto restart; | |
431 | ||
432 | case SAVE_EXPR: | |
433 | case NON_LVALUE_EXPR: | |
434 | case NOP_EXPR: | |
435 | exp = TREE_OPERAND (exp, 0); | |
436 | goto restart; | |
437 | ||
438 | case TRUTH_ORIF_EXPR: | |
439 | case TRUTH_ANDIF_EXPR: | |
440 | /* In && or ||, warn if 2nd operand has no side effect. */ | |
441 | exp = TREE_OPERAND (exp, 1); | |
442 | goto restart; | |
443 | ||
444 | case COMPOUND_EXPR: | |
445 | if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus)) | |
446 | return true; | |
447 | /* Let people do `(foo (), 0)' without a warning. */ | |
448 | if (TREE_CONSTANT (TREE_OPERAND (exp, 1))) | |
449 | return false; | |
450 | exp = TREE_OPERAND (exp, 1); | |
451 | goto restart; | |
452 | ||
453 | case COND_EXPR: | |
454 | /* If this is an expression with side effects, don't warn; this | |
455 | case commonly appears in macro expansions. */ | |
456 | if (TREE_SIDE_EFFECTS (exp)) | |
457 | return false; | |
458 | goto warn; | |
459 | ||
460 | case INDIRECT_REF: | |
461 | /* Don't warn about automatic dereferencing of references, since | |
462 | the user cannot control it. */ | |
463 | if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE) | |
464 | { | |
465 | exp = TREE_OPERAND (exp, 0); | |
466 | goto restart; | |
467 | } | |
468 | /* Fall through. */ | |
469 | ||
470 | default: | |
471 | /* Referencing a volatile value is a side effect, so don't warn. */ | |
472 | if ((DECL_P (exp) || REFERENCE_CLASS_P (exp)) | |
473 | && TREE_THIS_VOLATILE (exp)) | |
474 | return false; | |
475 | ||
476 | /* If this is an expression which has no operands, there is no value | |
477 | to be unused. There are no such language-independent codes, | |
478 | but front ends may define such. */ | |
479 | if (EXPRESSION_CLASS_P (exp) && TREE_OPERAND_LENGTH (exp) == 0) | |
480 | return false; | |
481 | ||
482 | warn: | |
483 | return warning_at (locus, OPT_Wunused_value, "value computed is not used"); | |
484 | } | |
485 | } | |
486 | ||
487 | /* Print a warning about casts that might indicate violation | |
488 | of strict aliasing rules if -Wstrict-aliasing is used and | |
489 | strict aliasing mode is in effect. OTYPE is the original | |
490 | TREE_TYPE of EXPR, and TYPE the type we're casting to. */ | |
491 | ||
492 | bool | |
493 | strict_aliasing_warning (tree otype, tree type, tree expr) | |
494 | { | |
495 | /* Strip pointer conversion chains and get to the correct original type. */ | |
496 | STRIP_NOPS (expr); | |
497 | otype = TREE_TYPE (expr); | |
498 | ||
499 | if (!(flag_strict_aliasing | |
500 | && POINTER_TYPE_P (type) | |
501 | && POINTER_TYPE_P (otype) | |
502 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
503 | /* If the type we are casting to is a ref-all pointer | |
504 | dereferencing it is always valid. */ | |
505 | || TYPE_REF_CAN_ALIAS_ALL (type)) | |
506 | return false; | |
507 | ||
508 | if ((warn_strict_aliasing > 1) && TREE_CODE (expr) == ADDR_EXPR | |
509 | && (DECL_P (TREE_OPERAND (expr, 0)) | |
510 | || handled_component_p (TREE_OPERAND (expr, 0)))) | |
511 | { | |
512 | /* Casting the address of an object to non void pointer. Warn | |
513 | if the cast breaks type based aliasing. */ | |
514 | if (!COMPLETE_TYPE_P (TREE_TYPE (type)) && warn_strict_aliasing == 2) | |
515 | { | |
516 | warning (OPT_Wstrict_aliasing, "type-punning to incomplete type " | |
517 | "might break strict-aliasing rules"); | |
518 | return true; | |
519 | } | |
520 | else | |
521 | { | |
522 | /* warn_strict_aliasing >= 3. This includes the default (3). | |
523 | Only warn if the cast is dereferenced immediately. */ | |
524 | alias_set_type set1 | |
525 | = get_alias_set (TREE_TYPE (TREE_OPERAND (expr, 0))); | |
526 | alias_set_type set2 = get_alias_set (TREE_TYPE (type)); | |
527 | ||
528 | if (set1 != set2 && set2 != 0 | |
529 | && (set1 == 0 | |
530 | || (!alias_set_subset_of (set2, set1) | |
531 | && !alias_sets_conflict_p (set1, set2)))) | |
532 | { | |
533 | warning (OPT_Wstrict_aliasing, "dereferencing type-punned " | |
534 | "pointer will break strict-aliasing rules"); | |
535 | return true; | |
536 | } | |
537 | else if (warn_strict_aliasing == 2 | |
538 | && !alias_sets_must_conflict_p (set1, set2)) | |
539 | { | |
540 | warning (OPT_Wstrict_aliasing, "dereferencing type-punned " | |
541 | "pointer might break strict-aliasing rules"); | |
542 | return true; | |
543 | } | |
544 | } | |
545 | } | |
546 | else if ((warn_strict_aliasing == 1) && !VOID_TYPE_P (TREE_TYPE (otype))) | |
547 | { | |
548 | /* At this level, warn for any conversions, even if an address is | |
549 | not taken in the same statement. This will likely produce many | |
550 | false positives, but could be useful to pinpoint problems that | |
551 | are not revealed at higher levels. */ | |
552 | alias_set_type set1 = get_alias_set (TREE_TYPE (otype)); | |
553 | alias_set_type set2 = get_alias_set (TREE_TYPE (type)); | |
554 | if (!COMPLETE_TYPE_P (type) | |
555 | || !alias_sets_must_conflict_p (set1, set2)) | |
556 | { | |
557 | warning (OPT_Wstrict_aliasing, "dereferencing type-punned " | |
558 | "pointer might break strict-aliasing rules"); | |
559 | return true; | |
560 | } | |
561 | } | |
562 | ||
563 | return false; | |
564 | } | |
565 | ||
566 | /* Warn about memset (&a, 0, sizeof (&a)); and similar mistakes with | |
567 | sizeof as last operand of certain builtins. */ | |
568 | ||
569 | void | |
570 | sizeof_pointer_memaccess_warning (location_t *sizeof_arg_loc, tree callee, | |
571 | vec<tree, va_gc> *params, tree *sizeof_arg, | |
572 | bool (*comp_types) (tree, tree)) | |
573 | { | |
574 | tree type, dest = NULL_TREE, src = NULL_TREE, tem; | |
575 | bool strop = false, cmp = false; | |
576 | unsigned int idx = ~0; | |
577 | location_t loc; | |
578 | ||
579 | if (TREE_CODE (callee) != FUNCTION_DECL | |
580 | || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
581 | || vec_safe_length (params) <= 1) | |
582 | return; | |
583 | ||
584 | switch (DECL_FUNCTION_CODE (callee)) | |
585 | { | |
586 | case BUILT_IN_STRNCMP: | |
587 | case BUILT_IN_STRNCASECMP: | |
588 | cmp = true; | |
589 | /* FALLTHRU */ | |
590 | case BUILT_IN_STRNCPY: | |
591 | case BUILT_IN_STRNCPY_CHK: | |
592 | case BUILT_IN_STRNCAT: | |
593 | case BUILT_IN_STRNCAT_CHK: | |
594 | case BUILT_IN_STPNCPY: | |
595 | case BUILT_IN_STPNCPY_CHK: | |
596 | strop = true; | |
597 | /* FALLTHRU */ | |
598 | case BUILT_IN_MEMCPY: | |
599 | case BUILT_IN_MEMCPY_CHK: | |
600 | case BUILT_IN_MEMMOVE: | |
601 | case BUILT_IN_MEMMOVE_CHK: | |
602 | if (params->length () < 3) | |
603 | return; | |
604 | src = (*params)[1]; | |
605 | dest = (*params)[0]; | |
606 | idx = 2; | |
607 | break; | |
608 | case BUILT_IN_BCOPY: | |
609 | if (params->length () < 3) | |
610 | return; | |
611 | src = (*params)[0]; | |
612 | dest = (*params)[1]; | |
613 | idx = 2; | |
614 | break; | |
615 | case BUILT_IN_MEMCMP: | |
616 | case BUILT_IN_BCMP: | |
617 | if (params->length () < 3) | |
618 | return; | |
619 | src = (*params)[1]; | |
620 | dest = (*params)[0]; | |
621 | idx = 2; | |
622 | cmp = true; | |
623 | break; | |
624 | case BUILT_IN_MEMSET: | |
625 | case BUILT_IN_MEMSET_CHK: | |
626 | if (params->length () < 3) | |
627 | return; | |
628 | dest = (*params)[0]; | |
629 | idx = 2; | |
630 | break; | |
631 | case BUILT_IN_BZERO: | |
632 | dest = (*params)[0]; | |
633 | idx = 1; | |
634 | break; | |
635 | case BUILT_IN_STRNDUP: | |
636 | src = (*params)[0]; | |
637 | strop = true; | |
638 | idx = 1; | |
639 | break; | |
640 | case BUILT_IN_MEMCHR: | |
641 | if (params->length () < 3) | |
642 | return; | |
643 | src = (*params)[0]; | |
644 | idx = 2; | |
645 | break; | |
646 | case BUILT_IN_SNPRINTF: | |
647 | case BUILT_IN_SNPRINTF_CHK: | |
648 | case BUILT_IN_VSNPRINTF: | |
649 | case BUILT_IN_VSNPRINTF_CHK: | |
650 | dest = (*params)[0]; | |
651 | idx = 1; | |
652 | strop = true; | |
653 | break; | |
654 | default: | |
655 | break; | |
656 | } | |
657 | ||
658 | if (idx >= 3) | |
659 | return; | |
660 | ||
661 | if (sizeof_arg[idx] == NULL || sizeof_arg[idx] == error_mark_node) | |
662 | return; | |
663 | ||
664 | type = TYPE_P (sizeof_arg[idx]) | |
665 | ? sizeof_arg[idx] : TREE_TYPE (sizeof_arg[idx]); | |
666 | if (!POINTER_TYPE_P (type)) | |
667 | return; | |
668 | ||
669 | if (dest | |
670 | && (tem = tree_strip_nop_conversions (dest)) | |
671 | && POINTER_TYPE_P (TREE_TYPE (tem)) | |
672 | && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) | |
673 | return; | |
674 | ||
675 | if (src | |
676 | && (tem = tree_strip_nop_conversions (src)) | |
677 | && POINTER_TYPE_P (TREE_TYPE (tem)) | |
678 | && comp_types (TREE_TYPE (TREE_TYPE (tem)), type)) | |
679 | return; | |
680 | ||
681 | loc = sizeof_arg_loc[idx]; | |
682 | ||
683 | if (dest && !cmp) | |
684 | { | |
685 | if (!TYPE_P (sizeof_arg[idx]) | |
686 | && operand_equal_p (dest, sizeof_arg[idx], 0) | |
687 | && comp_types (TREE_TYPE (dest), type)) | |
688 | { | |
689 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
690 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
691 | "argument to %<sizeof%> in %qD call is the same " | |
692 | "expression as the destination; did you mean to " | |
693 | "remove the addressof?", callee); | |
694 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
695 | == TYPE_PRECISION (char_type_node)) | |
696 | || strop) | |
697 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
698 | "argument to %<sizeof%> in %qD call is the same " | |
699 | "expression as the destination; did you mean to " | |
700 | "provide an explicit length?", callee); | |
701 | else | |
702 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
703 | "argument to %<sizeof%> in %qD call is the same " | |
704 | "expression as the destination; did you mean to " | |
705 | "dereference it?", callee); | |
706 | return; | |
707 | } | |
708 | ||
709 | if (POINTER_TYPE_P (TREE_TYPE (dest)) | |
710 | && !strop | |
711 | && comp_types (TREE_TYPE (dest), type) | |
712 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
713 | { | |
714 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
715 | "argument to %<sizeof%> in %qD call is the same " | |
716 | "pointer type %qT as the destination; expected %qT " | |
717 | "or an explicit length", callee, TREE_TYPE (dest), | |
718 | TREE_TYPE (TREE_TYPE (dest))); | |
719 | return; | |
720 | } | |
721 | } | |
722 | ||
723 | if (src && !cmp) | |
724 | { | |
725 | if (!TYPE_P (sizeof_arg[idx]) | |
726 | && operand_equal_p (src, sizeof_arg[idx], 0) | |
727 | && comp_types (TREE_TYPE (src), type)) | |
728 | { | |
729 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
730 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
731 | "argument to %<sizeof%> in %qD call is the same " | |
732 | "expression as the source; did you mean to " | |
733 | "remove the addressof?", callee); | |
734 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
735 | == TYPE_PRECISION (char_type_node)) | |
736 | || strop) | |
737 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
738 | "argument to %<sizeof%> in %qD call is the same " | |
739 | "expression as the source; did you mean to " | |
740 | "provide an explicit length?", callee); | |
741 | else | |
742 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
743 | "argument to %<sizeof%> in %qD call is the same " | |
744 | "expression as the source; did you mean to " | |
745 | "dereference it?", callee); | |
746 | return; | |
747 | } | |
748 | ||
749 | if (POINTER_TYPE_P (TREE_TYPE (src)) | |
750 | && !strop | |
751 | && comp_types (TREE_TYPE (src), type) | |
752 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
753 | { | |
754 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
755 | "argument to %<sizeof%> in %qD call is the same " | |
756 | "pointer type %qT as the source; expected %qT " | |
757 | "or an explicit length", callee, TREE_TYPE (src), | |
758 | TREE_TYPE (TREE_TYPE (src))); | |
759 | return; | |
760 | } | |
761 | } | |
762 | ||
763 | if (dest) | |
764 | { | |
765 | if (!TYPE_P (sizeof_arg[idx]) | |
766 | && operand_equal_p (dest, sizeof_arg[idx], 0) | |
767 | && comp_types (TREE_TYPE (dest), type)) | |
768 | { | |
769 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
770 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
771 | "argument to %<sizeof%> in %qD call is the same " | |
772 | "expression as the first source; did you mean to " | |
773 | "remove the addressof?", callee); | |
774 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
775 | == TYPE_PRECISION (char_type_node)) | |
776 | || strop) | |
777 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
778 | "argument to %<sizeof%> in %qD call is the same " | |
779 | "expression as the first source; did you mean to " | |
780 | "provide an explicit length?", callee); | |
781 | else | |
782 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
783 | "argument to %<sizeof%> in %qD call is the same " | |
784 | "expression as the first source; did you mean to " | |
785 | "dereference it?", callee); | |
786 | return; | |
787 | } | |
788 | ||
789 | if (POINTER_TYPE_P (TREE_TYPE (dest)) | |
790 | && !strop | |
791 | && comp_types (TREE_TYPE (dest), type) | |
792 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
793 | { | |
794 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
795 | "argument to %<sizeof%> in %qD call is the same " | |
796 | "pointer type %qT as the first source; expected %qT " | |
797 | "or an explicit length", callee, TREE_TYPE (dest), | |
798 | TREE_TYPE (TREE_TYPE (dest))); | |
799 | return; | |
800 | } | |
801 | } | |
802 | ||
803 | if (src) | |
804 | { | |
805 | if (!TYPE_P (sizeof_arg[idx]) | |
806 | && operand_equal_p (src, sizeof_arg[idx], 0) | |
807 | && comp_types (TREE_TYPE (src), type)) | |
808 | { | |
809 | if (TREE_CODE (sizeof_arg[idx]) == ADDR_EXPR && !strop) | |
810 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
811 | "argument to %<sizeof%> in %qD call is the same " | |
812 | "expression as the second source; did you mean to " | |
813 | "remove the addressof?", callee); | |
814 | else if ((TYPE_PRECISION (TREE_TYPE (type)) | |
815 | == TYPE_PRECISION (char_type_node)) | |
816 | || strop) | |
817 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
818 | "argument to %<sizeof%> in %qD call is the same " | |
819 | "expression as the second source; did you mean to " | |
820 | "provide an explicit length?", callee); | |
821 | else | |
822 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
823 | "argument to %<sizeof%> in %qD call is the same " | |
824 | "expression as the second source; did you mean to " | |
825 | "dereference it?", callee); | |
826 | return; | |
827 | } | |
828 | ||
829 | if (POINTER_TYPE_P (TREE_TYPE (src)) | |
830 | && !strop | |
831 | && comp_types (TREE_TYPE (src), type) | |
832 | && !VOID_TYPE_P (TREE_TYPE (type))) | |
833 | { | |
834 | warning_at (loc, OPT_Wsizeof_pointer_memaccess, | |
835 | "argument to %<sizeof%> in %qD call is the same " | |
836 | "pointer type %qT as the second source; expected %qT " | |
837 | "or an explicit length", callee, TREE_TYPE (src), | |
838 | TREE_TYPE (TREE_TYPE (src))); | |
839 | return; | |
840 | } | |
841 | } | |
842 | ||
843 | } | |
844 | ||
845 | /* Warn for unlikely, improbable, or stupid DECL declarations | |
846 | of `main'. */ | |
847 | ||
848 | void | |
849 | check_main_parameter_types (tree decl) | |
850 | { | |
851 | function_args_iterator iter; | |
852 | tree type; | |
853 | int argct = 0; | |
854 | ||
855 | FOREACH_FUNCTION_ARGS (TREE_TYPE (decl), type, iter) | |
856 | { | |
857 | /* XXX void_type_node belies the abstraction. */ | |
858 | if (type == void_type_node || type == error_mark_node) | |
859 | break; | |
860 | ||
861 | tree t = type; | |
862 | if (TYPE_ATOMIC (t)) | |
863 | pedwarn (input_location, OPT_Wmain, | |
864 | "%<_Atomic%>-qualified parameter type %qT of %q+D", | |
865 | type, decl); | |
866 | while (POINTER_TYPE_P (t)) | |
867 | { | |
868 | t = TREE_TYPE (t); | |
869 | if (TYPE_ATOMIC (t)) | |
870 | pedwarn (input_location, OPT_Wmain, | |
871 | "%<_Atomic%>-qualified parameter type %qT of %q+D", | |
872 | type, decl); | |
873 | } | |
874 | ||
875 | ++argct; | |
876 | switch (argct) | |
877 | { | |
878 | case 1: | |
879 | if (TYPE_MAIN_VARIANT (type) != integer_type_node) | |
880 | pedwarn (input_location, OPT_Wmain, | |
881 | "first argument of %q+D should be %<int%>", decl); | |
882 | break; | |
883 | ||
884 | case 2: | |
885 | if (TREE_CODE (type) != POINTER_TYPE | |
886 | || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE | |
887 | || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type))) | |
888 | != char_type_node)) | |
889 | pedwarn (input_location, OPT_Wmain, | |
890 | "second argument of %q+D should be %<char **%>", decl); | |
891 | break; | |
892 | ||
893 | case 3: | |
894 | if (TREE_CODE (type) != POINTER_TYPE | |
895 | || TREE_CODE (TREE_TYPE (type)) != POINTER_TYPE | |
896 | || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type))) | |
897 | != char_type_node)) | |
898 | pedwarn (input_location, OPT_Wmain, | |
899 | "third argument of %q+D should probably be " | |
900 | "%<char **%>", decl); | |
901 | break; | |
902 | } | |
903 | } | |
904 | ||
905 | /* It is intentional that this message does not mention the third | |
906 | argument because it's only mentioned in an appendix of the | |
907 | standard. */ | |
908 | if (argct > 0 && (argct < 2 || argct > 3)) | |
909 | pedwarn (input_location, OPT_Wmain, | |
910 | "%q+D takes only zero or two arguments", decl); | |
911 | ||
912 | if (stdarg_p (TREE_TYPE (decl))) | |
913 | pedwarn (input_location, OPT_Wmain, | |
914 | "%q+D declared as variadic function", decl); | |
915 | } | |
916 | ||
917 | /* Warns if the conversion of EXPR to TYPE may alter a value. | |
918 | This is a helper function for warnings_for_convert_and_check. */ | |
919 | ||
920 | static void | |
921 | conversion_warning (location_t loc, tree type, tree expr) | |
922 | { | |
923 | tree expr_type = TREE_TYPE (expr); | |
924 | enum conversion_safety conversion_kind; | |
925 | ||
926 | if (!warn_conversion && !warn_sign_conversion && !warn_float_conversion) | |
927 | return; | |
928 | ||
929 | /* This may happen, because for LHS op= RHS we preevaluate | |
930 | RHS and create C_MAYBE_CONST_EXPR <SAVE_EXPR <RHS>>, which | |
931 | means we could no longer see the code of the EXPR. */ | |
932 | if (TREE_CODE (expr) == C_MAYBE_CONST_EXPR) | |
933 | expr = C_MAYBE_CONST_EXPR_EXPR (expr); | |
934 | if (TREE_CODE (expr) == SAVE_EXPR) | |
935 | expr = TREE_OPERAND (expr, 0); | |
936 | ||
937 | switch (TREE_CODE (expr)) | |
938 | { | |
939 | case EQ_EXPR: | |
940 | case NE_EXPR: | |
941 | case LE_EXPR: | |
942 | case GE_EXPR: | |
943 | case LT_EXPR: | |
944 | case GT_EXPR: | |
945 | case TRUTH_ANDIF_EXPR: | |
946 | case TRUTH_ORIF_EXPR: | |
947 | case TRUTH_AND_EXPR: | |
948 | case TRUTH_OR_EXPR: | |
949 | case TRUTH_XOR_EXPR: | |
950 | case TRUTH_NOT_EXPR: | |
951 | /* Conversion from boolean to a signed:1 bit-field (which only | |
952 | can hold the values 0 and -1) doesn't lose information - but | |
953 | it does change the value. */ | |
954 | if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type)) | |
955 | warning_at (loc, OPT_Wconversion, | |
956 | "conversion to %qT from boolean expression", type); | |
957 | return; | |
958 | ||
959 | case REAL_CST: | |
960 | case INTEGER_CST: | |
961 | case COMPLEX_CST: | |
962 | conversion_kind = unsafe_conversion_p (loc, type, expr, true); | |
963 | if (conversion_kind == UNSAFE_REAL) | |
964 | warning_at (loc, OPT_Wfloat_conversion, | |
965 | "conversion to %qT alters %qT constant value", | |
966 | type, expr_type); | |
967 | else if (conversion_kind) | |
968 | warning_at (loc, OPT_Wconversion, | |
969 | "conversion to %qT alters %qT constant value", | |
970 | type, expr_type); | |
971 | return; | |
972 | ||
973 | case COND_EXPR: | |
974 | { | |
975 | /* In case of COND_EXPR, we do not care about the type of | |
976 | COND_EXPR, only about the conversion of each operand. */ | |
977 | tree op1 = TREE_OPERAND (expr, 1); | |
978 | tree op2 = TREE_OPERAND (expr, 2); | |
979 | ||
980 | conversion_warning (loc, type, op1); | |
981 | conversion_warning (loc, type, op2); | |
982 | return; | |
983 | } | |
984 | ||
985 | default: /* 'expr' is not a constant. */ | |
986 | conversion_kind = unsafe_conversion_p (loc, type, expr, true); | |
987 | if (conversion_kind == UNSAFE_REAL) | |
988 | warning_at (loc, OPT_Wfloat_conversion, | |
989 | "conversion to %qT from %qT may alter its value", | |
990 | type, expr_type); | |
991 | else if (conversion_kind == UNSAFE_IMAGINARY) | |
992 | warning_at (loc, OPT_Wconversion, | |
993 | "conversion to %qT from %qT discards imaginary component", | |
994 | type, expr_type); | |
995 | else if (conversion_kind) | |
996 | warning_at (loc, OPT_Wconversion, | |
997 | "conversion to %qT from %qT may alter its value", | |
998 | type, expr_type); | |
999 | } | |
1000 | } | |
1001 | ||
1002 | /* Produce warnings after a conversion. RESULT is the result of | |
1003 | converting EXPR to TYPE. This is a helper function for | |
1004 | convert_and_check and cp_convert_and_check. */ | |
1005 | ||
1006 | void | |
1007 | warnings_for_convert_and_check (location_t loc, tree type, tree expr, | |
1008 | tree result) | |
1009 | { | |
1010 | loc = expansion_point_location_if_in_system_header (loc); | |
1011 | ||
1012 | if (TREE_CODE (expr) == INTEGER_CST | |
1013 | && (TREE_CODE (type) == INTEGER_TYPE | |
1014 | || TREE_CODE (type) == ENUMERAL_TYPE) | |
1015 | && !int_fits_type_p (expr, type)) | |
1016 | { | |
1017 | /* Do not diagnose overflow in a constant expression merely | |
1018 | because a conversion overflowed. */ | |
1019 | if (TREE_OVERFLOW (result)) | |
1020 | TREE_OVERFLOW (result) = TREE_OVERFLOW (expr); | |
1021 | ||
1022 | if (TYPE_UNSIGNED (type)) | |
1023 | { | |
1024 | /* This detects cases like converting -129 or 256 to | |
1025 | unsigned char. */ | |
1026 | if (!int_fits_type_p (expr, c_common_signed_type (type))) | |
1027 | warning_at (loc, OPT_Woverflow, | |
1028 | "large integer implicitly truncated to unsigned type"); | |
1029 | else | |
1030 | conversion_warning (loc, type, expr); | |
1031 | } | |
1032 | else if (!int_fits_type_p (expr, c_common_unsigned_type (type))) | |
1033 | warning_at (loc, OPT_Woverflow, | |
1034 | "overflow in implicit constant conversion"); | |
1035 | /* No warning for converting 0x80000000 to int. */ | |
1036 | else if (pedantic | |
1037 | && (TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE | |
1038 | || TYPE_PRECISION (TREE_TYPE (expr)) | |
1039 | != TYPE_PRECISION (type))) | |
1040 | warning_at (loc, OPT_Woverflow, | |
1041 | "overflow in implicit constant conversion"); | |
1042 | ||
1043 | else | |
1044 | conversion_warning (loc, type, expr); | |
1045 | } | |
1046 | else if ((TREE_CODE (result) == INTEGER_CST | |
1047 | || TREE_CODE (result) == FIXED_CST) && TREE_OVERFLOW (result)) | |
1048 | warning_at (loc, OPT_Woverflow, | |
1049 | "overflow in implicit constant conversion"); | |
1050 | else | |
1051 | conversion_warning (loc, type, expr); | |
1052 | } | |
1053 | ||
1054 | /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach. | |
1055 | Used to verify that case values match up with enumerator values. */ | |
1056 | ||
1057 | static void | |
1058 | match_case_to_enum_1 (tree key, tree type, tree label) | |
1059 | { | |
1060 | char buf[WIDE_INT_PRINT_BUFFER_SIZE]; | |
1061 | ||
1062 | if (tree_fits_uhwi_p (key)) | |
1063 | print_dec (key, buf, UNSIGNED); | |
1064 | else if (tree_fits_shwi_p (key)) | |
1065 | print_dec (key, buf, SIGNED); | |
1066 | else | |
1067 | print_hex (key, buf); | |
1068 | ||
1069 | if (TYPE_NAME (type) == 0) | |
1070 | warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label)), | |
1071 | warn_switch ? OPT_Wswitch : OPT_Wswitch_enum, | |
1072 | "case value %qs not in enumerated type", | |
1073 | buf); | |
1074 | else | |
1075 | warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label)), | |
1076 | warn_switch ? OPT_Wswitch : OPT_Wswitch_enum, | |
1077 | "case value %qs not in enumerated type %qT", | |
1078 | buf, type); | |
1079 | } | |
1080 | ||
1081 | /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach. | |
1082 | Used to verify that case values match up with enumerator values. */ | |
1083 | ||
1084 | static int | |
1085 | match_case_to_enum (splay_tree_node node, void *data) | |
1086 | { | |
1087 | tree label = (tree) node->value; | |
1088 | tree type = (tree) data; | |
1089 | ||
1090 | /* Skip default case. */ | |
1091 | if (!CASE_LOW (label)) | |
1092 | return 0; | |
1093 | ||
1094 | /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear | |
1095 | when we did our enum->case scan. Reset our scratch bit after. */ | |
1096 | if (!CASE_LOW_SEEN (label)) | |
1097 | match_case_to_enum_1 (CASE_LOW (label), type, label); | |
1098 | else | |
1099 | CASE_LOW_SEEN (label) = 0; | |
1100 | ||
1101 | /* If CASE_HIGH is non-null, we have a range. If CASE_HIGH_SEEN is | |
1102 | not set, that means that CASE_HIGH did not appear when we did our | |
1103 | enum->case scan. Reset our scratch bit after. */ | |
1104 | if (CASE_HIGH (label)) | |
1105 | { | |
1106 | if (!CASE_HIGH_SEEN (label)) | |
1107 | match_case_to_enum_1 (CASE_HIGH (label), type, label); | |
1108 | else | |
1109 | CASE_HIGH_SEEN (label) = 0; | |
1110 | } | |
1111 | ||
1112 | return 0; | |
1113 | } | |
1114 | ||
1115 | /* Handle -Wswitch*. Called from the front end after parsing the | |
1116 | switch construct. */ | |
1117 | /* ??? Should probably be somewhere generic, since other languages | |
1118 | besides C and C++ would want this. At the moment, however, C/C++ | |
1119 | are the only tree-ssa languages that support enumerations at all, | |
1120 | so the point is moot. */ | |
1121 | ||
1122 | void | |
1123 | c_do_switch_warnings (splay_tree cases, location_t switch_location, | |
1124 | tree type, tree cond, bool bool_cond_p, | |
1125 | bool outside_range_p) | |
1126 | { | |
1127 | splay_tree_node default_node; | |
1128 | splay_tree_node node; | |
1129 | tree chain; | |
1130 | ||
1131 | if (!warn_switch && !warn_switch_enum && !warn_switch_default | |
1132 | && !warn_switch_bool) | |
1133 | return; | |
1134 | ||
1135 | default_node = splay_tree_lookup (cases, (splay_tree_key) NULL); | |
1136 | if (!default_node) | |
1137 | warning_at (switch_location, OPT_Wswitch_default, | |
1138 | "switch missing default case"); | |
1139 | ||
1140 | /* There are certain cases where -Wswitch-bool warnings aren't | |
1141 | desirable, such as | |
1142 | switch (boolean) | |
1143 | { | |
1144 | case true: ... | |
1145 | case false: ... | |
1146 | } | |
1147 | so be careful here. */ | |
1148 | if (warn_switch_bool && bool_cond_p) | |
1149 | { | |
1150 | splay_tree_node min_node; | |
1151 | /* If there's a default node, it's also the value with the minimal | |
1152 | key. So look at the penultimate key (if any). */ | |
1153 | if (default_node) | |
1154 | min_node = splay_tree_successor (cases, (splay_tree_key) NULL); | |
1155 | else | |
1156 | min_node = splay_tree_min (cases); | |
1157 | tree min = min_node ? (tree) min_node->key : NULL_TREE; | |
1158 | ||
1159 | splay_tree_node max_node = splay_tree_max (cases); | |
1160 | /* This might be a case range, so look at the value with the | |
1161 | maximal key and then check CASE_HIGH. */ | |
1162 | tree max = max_node ? (tree) max_node->value : NULL_TREE; | |
1163 | if (max) | |
1164 | max = CASE_HIGH (max) ? CASE_HIGH (max) : CASE_LOW (max); | |
1165 | ||
1166 | /* If there's a case value > 1 or < 0, that is outside bool | |
1167 | range, warn. */ | |
1168 | if (outside_range_p | |
1169 | || (max && wi::gts_p (max, 1)) | |
1170 | || (min && wi::lts_p (min, 0)) | |
1171 | /* And handle the | |
1172 | switch (boolean) | |
1173 | { | |
1174 | case true: ... | |
1175 | case false: ... | |
1176 | default: ... | |
1177 | } | |
1178 | case, where we want to warn. */ | |
1179 | || (default_node | |
1180 | && max && wi::eq_p (max, 1) | |
1181 | && min && wi::eq_p (min, 0))) | |
1182 | warning_at (switch_location, OPT_Wswitch_bool, | |
1183 | "switch condition has boolean value"); | |
1184 | } | |
1185 | ||
1186 | /* From here on, we only care about enumerated types. */ | |
1187 | if (!type || TREE_CODE (type) != ENUMERAL_TYPE) | |
1188 | return; | |
1189 | ||
1190 | /* From here on, we only care about -Wswitch and -Wswitch-enum. */ | |
1191 | if (!warn_switch_enum && !warn_switch) | |
1192 | return; | |
1193 | ||
1194 | /* Check the cases. Warn about case values which are not members of | |
1195 | the enumerated type. For -Wswitch-enum, or for -Wswitch when | |
1196 | there is no default case, check that exactly all enumeration | |
1197 | literals are covered by the cases. */ | |
1198 | ||
1199 | /* Clearing COND if it is not an integer constant simplifies | |
1200 | the tests inside the loop below. */ | |
1201 | if (TREE_CODE (cond) != INTEGER_CST) | |
1202 | cond = NULL_TREE; | |
1203 | ||
1204 | /* The time complexity here is O(N*lg(N)) worst case, but for the | |
1205 | common case of monotonically increasing enumerators, it is | |
1206 | O(N), since the nature of the splay tree will keep the next | |
1207 | element adjacent to the root at all times. */ | |
1208 | ||
1209 | for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain)) | |
1210 | { | |
1211 | tree value = TREE_VALUE (chain); | |
1212 | if (TREE_CODE (value) == CONST_DECL) | |
1213 | value = DECL_INITIAL (value); | |
1214 | node = splay_tree_lookup (cases, (splay_tree_key) value); | |
1215 | if (node) | |
1216 | { | |
1217 | /* Mark the CASE_LOW part of the case entry as seen. */ | |
1218 | tree label = (tree) node->value; | |
1219 | CASE_LOW_SEEN (label) = 1; | |
1220 | continue; | |
1221 | } | |
1222 | ||
1223 | /* Even though there wasn't an exact match, there might be a | |
1224 | case range which includes the enumerator's value. */ | |
1225 | node = splay_tree_predecessor (cases, (splay_tree_key) value); | |
1226 | if (node && CASE_HIGH ((tree) node->value)) | |
1227 | { | |
1228 | tree label = (tree) node->value; | |
1229 | int cmp = tree_int_cst_compare (CASE_HIGH (label), value); | |
1230 | if (cmp >= 0) | |
1231 | { | |
1232 | /* If we match the upper bound exactly, mark the CASE_HIGH | |
1233 | part of the case entry as seen. */ | |
1234 | if (cmp == 0) | |
1235 | CASE_HIGH_SEEN (label) = 1; | |
1236 | continue; | |
1237 | } | |
1238 | } | |
1239 | ||
1240 | /* We've now determined that this enumerated literal isn't | |
1241 | handled by the case labels of the switch statement. */ | |
1242 | ||
1243 | /* If the switch expression is a constant, we only really care | |
1244 | about whether that constant is handled by the switch. */ | |
1245 | if (cond && tree_int_cst_compare (cond, value)) | |
1246 | continue; | |
1247 | ||
1248 | /* If there is a default_node, the only relevant option is | |
1249 | Wswitch-enum. Otherwise, if both are enabled then we prefer | |
1250 | to warn using -Wswitch because -Wswitch is enabled by -Wall | |
1251 | while -Wswitch-enum is explicit. */ | |
1252 | warning_at (switch_location, | |
1253 | (default_node || !warn_switch | |
1254 | ? OPT_Wswitch_enum | |
1255 | : OPT_Wswitch), | |
1256 | "enumeration value %qE not handled in switch", | |
1257 | TREE_PURPOSE (chain)); | |
1258 | } | |
1259 | ||
1260 | /* Warn if there are case expressions that don't correspond to | |
1261 | enumerators. This can occur since C and C++ don't enforce | |
1262 | type-checking of assignments to enumeration variables. | |
1263 | ||
1264 | The time complexity here is now always O(N) worst case, since | |
1265 | we should have marked both the lower bound and upper bound of | |
1266 | every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN | |
1267 | above. This scan also resets those fields. */ | |
1268 | ||
1269 | splay_tree_foreach (cases, match_case_to_enum, type); | |
1270 | } | |
1271 | ||
1272 | /* Warn for A ?: C expressions (with B omitted) where A is a boolean | |
1273 | expression, because B will always be true. */ | |
1274 | ||
1275 | void | |
1276 | warn_for_omitted_condop (location_t location, tree cond) | |
1277 | { | |
1278 | /* In C++ template declarations it can happen that the type is dependent | |
1279 | and not yet known, thus TREE_TYPE (cond) == NULL_TREE. */ | |
1280 | if (truth_value_p (TREE_CODE (cond)) | |
1281 | || (TREE_TYPE (cond) != NULL_TREE | |
1282 | && TREE_CODE (TREE_TYPE (cond)) == BOOLEAN_TYPE)) | |
1283 | warning_at (location, OPT_Wparentheses, | |
1284 | "the omitted middle operand in ?: will always be %<true%>, " | |
1285 | "suggest explicit middle operand"); | |
1286 | } | |
1287 | ||
1288 | /* Give an error for storing into ARG, which is 'const'. USE indicates | |
1289 | how ARG was being used. */ | |
1290 | ||
1291 | void | |
1292 | readonly_error (location_t loc, tree arg, enum lvalue_use use) | |
1293 | { | |
1294 | gcc_assert (use == lv_assign || use == lv_increment || use == lv_decrement | |
1295 | || use == lv_asm); | |
1296 | /* Using this macro rather than (for example) arrays of messages | |
1297 | ensures that all the format strings are checked at compile | |
1298 | time. */ | |
1299 | #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A) \ | |
1300 | : (use == lv_increment ? (I) \ | |
1301 | : (use == lv_decrement ? (D) : (AS)))) | |
1302 | if (TREE_CODE (arg) == COMPONENT_REF) | |
1303 | { | |
1304 | if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0)))) | |
1305 | error_at (loc, READONLY_MSG (G_("assignment of member " | |
1306 | "%qD in read-only object"), | |
1307 | G_("increment of member " | |
1308 | "%qD in read-only object"), | |
1309 | G_("decrement of member " | |
1310 | "%qD in read-only object"), | |
1311 | G_("member %qD in read-only object " | |
1312 | "used as %<asm%> output")), | |
1313 | TREE_OPERAND (arg, 1)); | |
1314 | else | |
1315 | error_at (loc, READONLY_MSG (G_("assignment of read-only member %qD"), | |
1316 | G_("increment of read-only member %qD"), | |
1317 | G_("decrement of read-only member %qD"), | |
1318 | G_("read-only member %qD used as %<asm%> output")), | |
1319 | TREE_OPERAND (arg, 1)); | |
1320 | } | |
1321 | else if (VAR_P (arg)) | |
1322 | error_at (loc, READONLY_MSG (G_("assignment of read-only variable %qD"), | |
1323 | G_("increment of read-only variable %qD"), | |
1324 | G_("decrement of read-only variable %qD"), | |
1325 | G_("read-only variable %qD used as %<asm%> output")), | |
1326 | arg); | |
1327 | else if (TREE_CODE (arg) == PARM_DECL) | |
1328 | error_at (loc, READONLY_MSG (G_("assignment of read-only parameter %qD"), | |
1329 | G_("increment of read-only parameter %qD"), | |
1330 | G_("decrement of read-only parameter %qD"), | |
1331 | G_("read-only parameter %qD use as %<asm%> output")), | |
1332 | arg); | |
1333 | else if (TREE_CODE (arg) == RESULT_DECL) | |
1334 | { | |
1335 | gcc_assert (c_dialect_cxx ()); | |
1336 | error_at (loc, READONLY_MSG (G_("assignment of " | |
1337 | "read-only named return value %qD"), | |
1338 | G_("increment of " | |
1339 | "read-only named return value %qD"), | |
1340 | G_("decrement of " | |
1341 | "read-only named return value %qD"), | |
1342 | G_("read-only named return value %qD " | |
1343 | "used as %<asm%>output")), | |
1344 | arg); | |
1345 | } | |
1346 | else if (TREE_CODE (arg) == FUNCTION_DECL) | |
1347 | error_at (loc, READONLY_MSG (G_("assignment of function %qD"), | |
1348 | G_("increment of function %qD"), | |
1349 | G_("decrement of function %qD"), | |
1350 | G_("function %qD used as %<asm%> output")), | |
1351 | arg); | |
1352 | else | |
1353 | error_at (loc, READONLY_MSG (G_("assignment of read-only location %qE"), | |
1354 | G_("increment of read-only location %qE"), | |
1355 | G_("decrement of read-only location %qE"), | |
1356 | G_("read-only location %qE used as %<asm%> output")), | |
1357 | arg); | |
1358 | } | |
1359 | ||
1360 | /* Print an error message for an invalid lvalue. USE says | |
1361 | how the lvalue is being used and so selects the error message. LOC | |
1362 | is the location for the error. */ | |
1363 | ||
1364 | void | |
1365 | lvalue_error (location_t loc, enum lvalue_use use) | |
1366 | { | |
1367 | switch (use) | |
1368 | { | |
1369 | case lv_assign: | |
1370 | error_at (loc, "lvalue required as left operand of assignment"); | |
1371 | break; | |
1372 | case lv_increment: | |
1373 | error_at (loc, "lvalue required as increment operand"); | |
1374 | break; | |
1375 | case lv_decrement: | |
1376 | error_at (loc, "lvalue required as decrement operand"); | |
1377 | break; | |
1378 | case lv_addressof: | |
1379 | error_at (loc, "lvalue required as unary %<&%> operand"); | |
1380 | break; | |
1381 | case lv_asm: | |
1382 | error_at (loc, "lvalue required in asm statement"); | |
1383 | break; | |
1384 | default: | |
1385 | gcc_unreachable (); | |
1386 | } | |
1387 | } | |
1388 | ||
1389 | /* Print an error message for an invalid indirection of type TYPE. | |
1390 | ERRSTRING is the name of the operator for the indirection. */ | |
1391 | ||
1392 | void | |
1393 | invalid_indirection_error (location_t loc, tree type, ref_operator errstring) | |
1394 | { | |
1395 | switch (errstring) | |
1396 | { | |
1397 | case RO_NULL: | |
1398 | gcc_assert (c_dialect_cxx ()); | |
1399 | error_at (loc, "invalid type argument (have %qT)", type); | |
1400 | break; | |
1401 | case RO_ARRAY_INDEXING: | |
1402 | error_at (loc, | |
1403 | "invalid type argument of array indexing (have %qT)", | |
1404 | type); | |
1405 | break; | |
1406 | case RO_UNARY_STAR: | |
1407 | error_at (loc, | |
1408 | "invalid type argument of unary %<*%> (have %qT)", | |
1409 | type); | |
1410 | break; | |
1411 | case RO_ARROW: | |
1412 | error_at (loc, | |
1413 | "invalid type argument of %<->%> (have %qT)", | |
1414 | type); | |
1415 | break; | |
1416 | case RO_ARROW_STAR: | |
1417 | error_at (loc, | |
1418 | "invalid type argument of %<->*%> (have %qT)", | |
1419 | type); | |
1420 | break; | |
1421 | case RO_IMPLICIT_CONVERSION: | |
1422 | error_at (loc, | |
1423 | "invalid type argument of implicit conversion (have %qT)", | |
1424 | type); | |
1425 | break; | |
1426 | default: | |
1427 | gcc_unreachable (); | |
1428 | } | |
1429 | } | |
1430 | ||
1431 | /* Subscripting with type char is likely to lose on a machine where | |
1432 | chars are signed. So warn on any machine, but optionally. Don't | |
1433 | warn for unsigned char since that type is safe. Don't warn for | |
1434 | signed char because anyone who uses that must have done so | |
1435 | deliberately. Furthermore, we reduce the false positive load by | |
1436 | warning only for non-constant value of type char. */ | |
1437 | ||
1438 | void | |
1439 | warn_array_subscript_with_type_char (location_t loc, tree index) | |
1440 | { | |
1441 | if (TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node | |
1442 | && TREE_CODE (index) != INTEGER_CST) | |
1443 | warning_at (loc, OPT_Wchar_subscripts, | |
1444 | "array subscript has type %<char%>"); | |
1445 | } | |
1446 | ||
1447 | /* Implement -Wparentheses for the unexpected C precedence rules, to | |
1448 | cover cases like x + y << z which readers are likely to | |
1449 | misinterpret. We have seen an expression in which CODE is a binary | |
1450 | operator used to combine expressions ARG_LEFT and ARG_RIGHT, which | |
1451 | before folding had CODE_LEFT and CODE_RIGHT. CODE_LEFT and | |
1452 | CODE_RIGHT may be ERROR_MARK, which means that that side of the | |
1453 | expression was not formed using a binary or unary operator, or it | |
1454 | was enclosed in parentheses. */ | |
1455 | ||
1456 | void | |
1457 | warn_about_parentheses (location_t loc, enum tree_code code, | |
1458 | enum tree_code code_left, tree arg_left, | |
1459 | enum tree_code code_right, tree arg_right) | |
1460 | { | |
1461 | if (!warn_parentheses) | |
1462 | return; | |
1463 | ||
1464 | /* This macro tests that the expression ARG with original tree code | |
1465 | CODE appears to be a boolean expression. or the result of folding a | |
1466 | boolean expression. */ | |
1467 | #define APPEARS_TO_BE_BOOLEAN_EXPR_P(CODE, ARG) \ | |
1468 | (truth_value_p (TREE_CODE (ARG)) \ | |
1469 | || TREE_CODE (TREE_TYPE (ARG)) == BOOLEAN_TYPE \ | |
1470 | /* Folding may create 0 or 1 integers from other expressions. */ \ | |
1471 | || ((CODE) != INTEGER_CST \ | |
1472 | && (integer_onep (ARG) || integer_zerop (ARG)))) | |
1473 | ||
1474 | switch (code) | |
1475 | { | |
1476 | case LSHIFT_EXPR: | |
1477 | if (code_left == PLUS_EXPR) | |
1478 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1479 | "suggest parentheses around %<+%> inside %<<<%>"); | |
1480 | else if (code_right == PLUS_EXPR) | |
1481 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1482 | "suggest parentheses around %<+%> inside %<<<%>"); | |
1483 | else if (code_left == MINUS_EXPR) | |
1484 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1485 | "suggest parentheses around %<-%> inside %<<<%>"); | |
1486 | else if (code_right == MINUS_EXPR) | |
1487 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1488 | "suggest parentheses around %<-%> inside %<<<%>"); | |
1489 | return; | |
1490 | ||
1491 | case RSHIFT_EXPR: | |
1492 | if (code_left == PLUS_EXPR) | |
1493 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1494 | "suggest parentheses around %<+%> inside %<>>%>"); | |
1495 | else if (code_right == PLUS_EXPR) | |
1496 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1497 | "suggest parentheses around %<+%> inside %<>>%>"); | |
1498 | else if (code_left == MINUS_EXPR) | |
1499 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1500 | "suggest parentheses around %<-%> inside %<>>%>"); | |
1501 | else if (code_right == MINUS_EXPR) | |
1502 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1503 | "suggest parentheses around %<-%> inside %<>>%>"); | |
1504 | return; | |
1505 | ||
1506 | case TRUTH_ORIF_EXPR: | |
1507 | if (code_left == TRUTH_ANDIF_EXPR) | |
1508 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1509 | "suggest parentheses around %<&&%> within %<||%>"); | |
1510 | else if (code_right == TRUTH_ANDIF_EXPR) | |
1511 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1512 | "suggest parentheses around %<&&%> within %<||%>"); | |
1513 | return; | |
1514 | ||
1515 | case BIT_IOR_EXPR: | |
1516 | if (code_left == BIT_AND_EXPR || code_left == BIT_XOR_EXPR | |
1517 | || code_left == PLUS_EXPR || code_left == MINUS_EXPR) | |
1518 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1519 | "suggest parentheses around arithmetic in operand of %<|%>"); | |
1520 | else if (code_right == BIT_AND_EXPR || code_right == BIT_XOR_EXPR | |
1521 | || code_right == PLUS_EXPR || code_right == MINUS_EXPR) | |
1522 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1523 | "suggest parentheses around arithmetic in operand of %<|%>"); | |
1524 | /* Check cases like x|y==z */ | |
1525 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1526 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1527 | "suggest parentheses around comparison in operand of %<|%>"); | |
1528 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1529 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1530 | "suggest parentheses around comparison in operand of %<|%>"); | |
1531 | /* Check cases like !x | y */ | |
1532 | else if (code_left == TRUTH_NOT_EXPR | |
1533 | && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right, arg_right)) | |
1534 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1535 | "suggest parentheses around operand of " | |
1536 | "%<!%> or change %<|%> to %<||%> or %<!%> to %<~%>"); | |
1537 | return; | |
1538 | ||
1539 | case BIT_XOR_EXPR: | |
1540 | if (code_left == BIT_AND_EXPR | |
1541 | || code_left == PLUS_EXPR || code_left == MINUS_EXPR) | |
1542 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1543 | "suggest parentheses around arithmetic in operand of %<^%>"); | |
1544 | else if (code_right == BIT_AND_EXPR | |
1545 | || code_right == PLUS_EXPR || code_right == MINUS_EXPR) | |
1546 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1547 | "suggest parentheses around arithmetic in operand of %<^%>"); | |
1548 | /* Check cases like x^y==z */ | |
1549 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1550 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1551 | "suggest parentheses around comparison in operand of %<^%>"); | |
1552 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1553 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1554 | "suggest parentheses around comparison in operand of %<^%>"); | |
1555 | return; | |
1556 | ||
1557 | case BIT_AND_EXPR: | |
1558 | if (code_left == PLUS_EXPR) | |
1559 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1560 | "suggest parentheses around %<+%> in operand of %<&%>"); | |
1561 | else if (code_right == PLUS_EXPR) | |
1562 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1563 | "suggest parentheses around %<+%> in operand of %<&%>"); | |
1564 | else if (code_left == MINUS_EXPR) | |
1565 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1566 | "suggest parentheses around %<-%> in operand of %<&%>"); | |
1567 | else if (code_right == MINUS_EXPR) | |
1568 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1569 | "suggest parentheses around %<-%> in operand of %<&%>"); | |
1570 | /* Check cases like x&y==z */ | |
1571 | else if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1572 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1573 | "suggest parentheses around comparison in operand of %<&%>"); | |
1574 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1575 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1576 | "suggest parentheses around comparison in operand of %<&%>"); | |
1577 | /* Check cases like !x & y */ | |
1578 | else if (code_left == TRUTH_NOT_EXPR | |
1579 | && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right, arg_right)) | |
1580 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1581 | "suggest parentheses around operand of " | |
1582 | "%<!%> or change %<&%> to %<&&%> or %<!%> to %<~%>"); | |
1583 | return; | |
1584 | ||
1585 | case EQ_EXPR: | |
1586 | if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1587 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1588 | "suggest parentheses around comparison in operand of %<==%>"); | |
1589 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1590 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1591 | "suggest parentheses around comparison in operand of %<==%>"); | |
1592 | return; | |
1593 | case NE_EXPR: | |
1594 | if (TREE_CODE_CLASS (code_left) == tcc_comparison) | |
1595 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1596 | "suggest parentheses around comparison in operand of %<!=%>"); | |
1597 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison) | |
1598 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1599 | "suggest parentheses around comparison in operand of %<!=%>"); | |
1600 | return; | |
1601 | ||
1602 | default: | |
1603 | if (TREE_CODE_CLASS (code) == tcc_comparison) | |
1604 | { | |
1605 | if (TREE_CODE_CLASS (code_left) == tcc_comparison | |
1606 | && code_left != NE_EXPR && code_left != EQ_EXPR | |
1607 | && INTEGRAL_TYPE_P (TREE_TYPE (arg_left))) | |
1608 | warning_at (EXPR_LOC_OR_LOC (arg_left, loc), OPT_Wparentheses, | |
1609 | "comparisons like %<X<=Y<=Z%> do not " | |
1610 | "have their mathematical meaning"); | |
1611 | else if (TREE_CODE_CLASS (code_right) == tcc_comparison | |
1612 | && code_right != NE_EXPR && code_right != EQ_EXPR | |
1613 | && INTEGRAL_TYPE_P (TREE_TYPE (arg_right))) | |
1614 | warning_at (EXPR_LOC_OR_LOC (arg_right, loc), OPT_Wparentheses, | |
1615 | "comparisons like %<X<=Y<=Z%> do not " | |
1616 | "have their mathematical meaning"); | |
1617 | } | |
1618 | return; | |
1619 | } | |
1620 | #undef NOT_A_BOOLEAN_EXPR_P | |
1621 | } | |
1622 | ||
1623 | /* If LABEL (a LABEL_DECL) has not been used, issue a warning. */ | |
1624 | ||
1625 | void | |
1626 | warn_for_unused_label (tree label) | |
1627 | { | |
1628 | if (!TREE_USED (label)) | |
1629 | { | |
1630 | if (DECL_INITIAL (label)) | |
1631 | warning (OPT_Wunused_label, "label %q+D defined but not used", label); | |
1632 | else | |
1633 | warning (OPT_Wunused_label, "label %q+D declared but not defined", label); | |
1634 | } | |
1635 | } | |
1636 | ||
1637 | /* Warn for division by zero according to the value of DIVISOR. LOC | |
1638 | is the location of the division operator. */ | |
1639 | ||
1640 | void | |
1641 | warn_for_div_by_zero (location_t loc, tree divisor) | |
1642 | { | |
1643 | /* If DIVISOR is zero, and has integral or fixed-point type, issue a warning | |
1644 | about division by zero. Do not issue a warning if DIVISOR has a | |
1645 | floating-point type, since we consider 0.0/0.0 a valid way of | |
1646 | generating a NaN. */ | |
1647 | if (c_inhibit_evaluation_warnings == 0 | |
1648 | && (integer_zerop (divisor) || fixed_zerop (divisor))) | |
1649 | warning_at (loc, OPT_Wdiv_by_zero, "division by zero"); | |
1650 | } | |
1651 | ||
1652 | /* Warn for patterns where memset appears to be used incorrectly. The | |
1653 | warning location should be LOC. ARG0, and ARG2 are the first and | |
1654 | last arguments to the call, while LITERAL_ZERO_MASK has a 1 bit for | |
1655 | each argument that was a literal zero. */ | |
1656 | ||
1657 | void | |
1658 | warn_for_memset (location_t loc, tree arg0, tree arg2, | |
1659 | int literal_zero_mask) | |
1660 | { | |
1661 | if (warn_memset_transposed_args | |
1662 | && integer_zerop (arg2) | |
1663 | && (literal_zero_mask & (1 << 2)) != 0 | |
1664 | && (literal_zero_mask & (1 << 1)) == 0) | |
1665 | warning_at (loc, OPT_Wmemset_transposed_args, | |
1666 | "%<memset%> used with constant zero length " | |
1667 | "parameter; this could be due to transposed " | |
1668 | "parameters"); | |
1669 | ||
1670 | if (warn_memset_elt_size && TREE_CODE (arg2) == INTEGER_CST) | |
1671 | { | |
1672 | STRIP_NOPS (arg0); | |
1673 | if (TREE_CODE (arg0) == ADDR_EXPR) | |
1674 | arg0 = TREE_OPERAND (arg0, 0); | |
1675 | tree type = TREE_TYPE (arg0); | |
1676 | if (type != NULL_TREE && TREE_CODE (type) == ARRAY_TYPE) | |
1677 | { | |
1678 | tree elt_type = TREE_TYPE (type); | |
1679 | tree domain = TYPE_DOMAIN (type); | |
1680 | if (!integer_onep (TYPE_SIZE_UNIT (elt_type)) | |
1681 | && domain != NULL_TREE | |
1682 | && TYPE_MAXVAL (domain) | |
1683 | && TYPE_MINVAL (domain) | |
1684 | && integer_zerop (TYPE_MINVAL (domain)) | |
1685 | && integer_onep (fold_build2 (MINUS_EXPR, domain, | |
1686 | arg2, | |
1687 | TYPE_MAXVAL (domain)))) | |
1688 | warning_at (loc, OPT_Wmemset_elt_size, | |
1689 | "%<memset%> used with length equal to " | |
1690 | "number of elements without multiplication " | |
1691 | "by element size"); | |
1692 | } | |
1693 | } | |
1694 | } | |
1695 | ||
1696 | /* Subroutine of build_binary_op. Give warnings for comparisons | |
1697 | between signed and unsigned quantities that may fail. Do the | |
1698 | checking based on the original operand trees ORIG_OP0 and ORIG_OP1, | |
1699 | so that casts will be considered, but default promotions won't | |
1700 | be. | |
1701 | ||
1702 | LOCATION is the location of the comparison operator. | |
1703 | ||
1704 | The arguments of this function map directly to local variables | |
1705 | of build_binary_op. */ | |
1706 | ||
1707 | void | |
1708 | warn_for_sign_compare (location_t location, | |
1709 | tree orig_op0, tree orig_op1, | |
1710 | tree op0, tree op1, | |
1711 | tree result_type, enum tree_code resultcode) | |
1712 | { | |
1713 | int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0)); | |
1714 | int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1)); | |
1715 | int unsignedp0, unsignedp1; | |
1716 | ||
1717 | /* In C++, check for comparison of different enum types. */ | |
1718 | if (c_dialect_cxx() | |
1719 | && TREE_CODE (TREE_TYPE (orig_op0)) == ENUMERAL_TYPE | |
1720 | && TREE_CODE (TREE_TYPE (orig_op1)) == ENUMERAL_TYPE | |
1721 | && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0)) | |
1722 | != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1))) | |
1723 | { | |
1724 | warning_at (location, | |
1725 | OPT_Wsign_compare, "comparison between types %qT and %qT", | |
1726 | TREE_TYPE (orig_op0), TREE_TYPE (orig_op1)); | |
1727 | } | |
1728 | ||
1729 | /* Do not warn if the comparison is being done in a signed type, | |
1730 | since the signed type will only be chosen if it can represent | |
1731 | all the values of the unsigned type. */ | |
1732 | if (!TYPE_UNSIGNED (result_type)) | |
1733 | /* OK */; | |
1734 | /* Do not warn if both operands are unsigned. */ | |
1735 | else if (op0_signed == op1_signed) | |
1736 | /* OK */; | |
1737 | else | |
1738 | { | |
1739 | tree sop, uop, base_type; | |
1740 | bool ovf; | |
1741 | ||
1742 | if (op0_signed) | |
1743 | sop = orig_op0, uop = orig_op1; | |
1744 | else | |
1745 | sop = orig_op1, uop = orig_op0; | |
1746 | ||
1747 | STRIP_TYPE_NOPS (sop); | |
1748 | STRIP_TYPE_NOPS (uop); | |
1749 | base_type = (TREE_CODE (result_type) == COMPLEX_TYPE | |
1750 | ? TREE_TYPE (result_type) : result_type); | |
1751 | ||
1752 | /* Do not warn if the signed quantity is an unsuffixed integer | |
1753 | literal (or some static constant expression involving such | |
1754 | literals or a conditional expression involving such literals) | |
1755 | and it is non-negative. */ | |
1756 | if (tree_expr_nonnegative_warnv_p (sop, &ovf)) | |
1757 | /* OK */; | |
1758 | /* Do not warn if the comparison is an equality operation, the | |
1759 | unsigned quantity is an integral constant, and it would fit | |
1760 | in the result if the result were signed. */ | |
1761 | else if (TREE_CODE (uop) == INTEGER_CST | |
1762 | && (resultcode == EQ_EXPR || resultcode == NE_EXPR) | |
1763 | && int_fits_type_p (uop, c_common_signed_type (base_type))) | |
1764 | /* OK */; | |
1765 | /* In C, do not warn if the unsigned quantity is an enumeration | |
1766 | constant and its maximum value would fit in the result if the | |
1767 | result were signed. */ | |
1768 | else if (!c_dialect_cxx() && TREE_CODE (uop) == INTEGER_CST | |
1769 | && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE | |
1770 | && int_fits_type_p (TYPE_MAX_VALUE (TREE_TYPE (uop)), | |
1771 | c_common_signed_type (base_type))) | |
1772 | /* OK */; | |
1773 | else | |
1774 | warning_at (location, | |
1775 | OPT_Wsign_compare, | |
1776 | "comparison between signed and unsigned integer expressions"); | |
1777 | } | |
1778 | ||
1779 | /* Warn if two unsigned values are being compared in a size larger | |
1780 | than their original size, and one (and only one) is the result of | |
1781 | a `~' operator. This comparison will always fail. | |
1782 | ||
1783 | Also warn if one operand is a constant, and the constant does not | |
1784 | have all bits set that are set in the ~ operand when it is | |
1785 | extended. */ | |
1786 | ||
1787 | op0 = c_common_get_narrower (op0, &unsignedp0); | |
1788 | op1 = c_common_get_narrower (op1, &unsignedp1); | |
1789 | ||
1790 | if ((TREE_CODE (op0) == BIT_NOT_EXPR) | |
1791 | ^ (TREE_CODE (op1) == BIT_NOT_EXPR)) | |
1792 | { | |
1793 | if (TREE_CODE (op0) == BIT_NOT_EXPR) | |
1794 | op0 = c_common_get_narrower (TREE_OPERAND (op0, 0), &unsignedp0); | |
1795 | if (TREE_CODE (op1) == BIT_NOT_EXPR) | |
1796 | op1 = c_common_get_narrower (TREE_OPERAND (op1, 0), &unsignedp1); | |
1797 | ||
1798 | if (tree_fits_shwi_p (op0) || tree_fits_shwi_p (op1)) | |
1799 | { | |
1800 | tree primop; | |
1801 | HOST_WIDE_INT constant, mask; | |
1802 | int unsignedp; | |
1803 | unsigned int bits; | |
1804 | ||
1805 | if (tree_fits_shwi_p (op0)) | |
1806 | { | |
1807 | primop = op1; | |
1808 | unsignedp = unsignedp1; | |
1809 | constant = tree_to_shwi (op0); | |
1810 | } | |
1811 | else | |
1812 | { | |
1813 | primop = op0; | |
1814 | unsignedp = unsignedp0; | |
1815 | constant = tree_to_shwi (op1); | |
1816 | } | |
1817 | ||
1818 | bits = TYPE_PRECISION (TREE_TYPE (primop)); | |
1819 | if (bits < TYPE_PRECISION (result_type) | |
1820 | && bits < HOST_BITS_PER_LONG && unsignedp) | |
1821 | { | |
1822 | mask = HOST_WIDE_INT_M1U << bits; | |
1823 | if ((mask & constant) != mask) | |
1824 | { | |
1825 | if (constant == 0) | |
1826 | warning_at (location, OPT_Wsign_compare, | |
1827 | "promoted ~unsigned is always non-zero"); | |
1828 | else | |
1829 | warning_at (location, OPT_Wsign_compare, | |
1830 | "comparison of promoted ~unsigned with constant"); | |
1831 | } | |
1832 | } | |
1833 | } | |
1834 | else if (unsignedp0 && unsignedp1 | |
1835 | && (TYPE_PRECISION (TREE_TYPE (op0)) | |
1836 | < TYPE_PRECISION (result_type)) | |
1837 | && (TYPE_PRECISION (TREE_TYPE (op1)) | |
1838 | < TYPE_PRECISION (result_type))) | |
1839 | warning_at (location, OPT_Wsign_compare, | |
1840 | "comparison of promoted ~unsigned with unsigned"); | |
1841 | } | |
1842 | } | |
1843 | ||
1844 | /* RESULT_TYPE is the result of converting TYPE1 and TYPE2 to a common | |
1845 | type via c_common_type. If -Wdouble-promotion is in use, and the | |
1846 | conditions for warning have been met, issue a warning. GMSGID is | |
1847 | the warning message. It must have two %T specifiers for the type | |
1848 | that was converted (generally "float") and the type to which it was | |
1849 | converted (generally "double), respectively. LOC is the location | |
1850 | to which the awrning should refer. */ | |
1851 | ||
1852 | void | |
1853 | do_warn_double_promotion (tree result_type, tree type1, tree type2, | |
1854 | const char *gmsgid, location_t loc) | |
1855 | { | |
1856 | tree source_type; | |
1857 | ||
1858 | if (!warn_double_promotion) | |
1859 | return; | |
1860 | /* If the conversion will not occur at run-time, there is no need to | |
1861 | warn about it. */ | |
1862 | if (c_inhibit_evaluation_warnings) | |
1863 | return; | |
1864 | if (TYPE_MAIN_VARIANT (result_type) != double_type_node | |
1865 | && TYPE_MAIN_VARIANT (result_type) != complex_double_type_node) | |
1866 | return; | |
1867 | if (TYPE_MAIN_VARIANT (type1) == float_type_node | |
1868 | || TYPE_MAIN_VARIANT (type1) == complex_float_type_node) | |
1869 | source_type = type1; | |
1870 | else if (TYPE_MAIN_VARIANT (type2) == float_type_node | |
1871 | || TYPE_MAIN_VARIANT (type2) == complex_float_type_node) | |
1872 | source_type = type2; | |
1873 | else | |
1874 | return; | |
1875 | warning_at (loc, OPT_Wdouble_promotion, gmsgid, source_type, result_type); | |
1876 | } | |
1877 | ||
1878 | /* Possibly warn about unused parameters. */ | |
1879 | ||
1880 | void | |
1881 | do_warn_unused_parameter (tree fn) | |
1882 | { | |
1883 | tree decl; | |
1884 | ||
1885 | for (decl = DECL_ARGUMENTS (fn); | |
1886 | decl; decl = DECL_CHAIN (decl)) | |
1887 | if (!TREE_USED (decl) && TREE_CODE (decl) == PARM_DECL | |
1888 | && DECL_NAME (decl) && !DECL_ARTIFICIAL (decl) | |
1889 | && !TREE_NO_WARNING (decl)) | |
1890 | warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wunused_parameter, | |
1891 | "unused parameter %qD", decl); | |
1892 | } | |
1893 | ||
1894 | /* If DECL is a typedef that is declared in the current function, | |
1895 | record it for the purpose of -Wunused-local-typedefs. */ | |
1896 | ||
1897 | void | |
1898 | record_locally_defined_typedef (tree decl) | |
1899 | { | |
1900 | struct c_language_function *l; | |
1901 | ||
1902 | if (!warn_unused_local_typedefs | |
1903 | || cfun == NULL | |
1904 | /* if this is not a locally defined typedef then we are not | |
1905 | interested. */ | |
1906 | || !is_typedef_decl (decl) | |
1907 | || !decl_function_context (decl)) | |
1908 | return; | |
1909 | ||
1910 | l = (struct c_language_function *) cfun->language; | |
1911 | vec_safe_push (l->local_typedefs, decl); | |
1912 | } | |
1913 | ||
1914 | /* If T is a TYPE_DECL declared locally, mark it as used. */ | |
1915 | ||
1916 | void | |
1917 | maybe_record_typedef_use (tree t) | |
1918 | { | |
1919 | if (!is_typedef_decl (t)) | |
1920 | return; | |
1921 | ||
1922 | TREE_USED (t) = true; | |
1923 | } | |
1924 | ||
1925 | /* Warn if there are some unused locally defined typedefs in the | |
1926 | current function. */ | |
1927 | ||
1928 | void | |
1929 | maybe_warn_unused_local_typedefs (void) | |
1930 | { | |
1931 | int i; | |
1932 | tree decl; | |
1933 | /* The number of times we have emitted -Wunused-local-typedefs | |
1934 | warnings. If this is different from errorcount, that means some | |
1935 | unrelated errors have been issued. In which case, we'll avoid | |
1936 | emitting "unused-local-typedefs" warnings. */ | |
1937 | static int unused_local_typedefs_warn_count; | |
1938 | struct c_language_function *l; | |
1939 | ||
1940 | if (cfun == NULL) | |
1941 | return; | |
1942 | ||
1943 | if ((l = (struct c_language_function *) cfun->language) == NULL) | |
1944 | return; | |
1945 | ||
1946 | if (warn_unused_local_typedefs | |
1947 | && errorcount == unused_local_typedefs_warn_count) | |
1948 | { | |
1949 | FOR_EACH_VEC_SAFE_ELT (l->local_typedefs, i, decl) | |
1950 | if (!TREE_USED (decl)) | |
1951 | warning_at (DECL_SOURCE_LOCATION (decl), | |
1952 | OPT_Wunused_local_typedefs, | |
1953 | "typedef %qD locally defined but not used", decl); | |
1954 | unused_local_typedefs_warn_count = errorcount; | |
1955 | } | |
1956 | ||
1957 | vec_free (l->local_typedefs); | |
1958 | } | |
1959 | ||
1960 | /* If we're creating an if-else-if condition chain, first see if we | |
1961 | already have this COND in the CHAIN. If so, warn and don't add COND | |
1962 | into the vector, otherwise add the COND there. LOC is the location | |
1963 | of COND. */ | |
1964 | ||
1965 | void | |
1966 | warn_duplicated_cond_add_or_warn (location_t loc, tree cond, vec<tree> **chain) | |
1967 | { | |
1968 | /* No chain has been created yet. Do nothing. */ | |
1969 | if (*chain == NULL) | |
1970 | return; | |
1971 | ||
1972 | if (TREE_SIDE_EFFECTS (cond)) | |
1973 | { | |
1974 | /* Uh-oh! This condition has a side-effect, thus invalidates | |
1975 | the whole chain. */ | |
1976 | delete *chain; | |
1977 | *chain = NULL; | |
1978 | return; | |
1979 | } | |
1980 | ||
1981 | unsigned int ix; | |
1982 | tree t; | |
1983 | bool found = false; | |
1984 | FOR_EACH_VEC_ELT (**chain, ix, t) | |
1985 | if (operand_equal_p (cond, t, 0)) | |
1986 | { | |
1987 | if (warning_at (loc, OPT_Wduplicated_cond, | |
1988 | "duplicated %<if%> condition")) | |
1989 | inform (EXPR_LOCATION (t), "previously used here"); | |
1990 | found = true; | |
1991 | break; | |
1992 | } | |
1993 | ||
1994 | if (!found | |
1995 | && !CONSTANT_CLASS_P (cond) | |
1996 | /* Don't infinitely grow the chain. */ | |
1997 | && (*chain)->length () < 512) | |
1998 | (*chain)->safe_push (cond); | |
1999 | } | |
2000 | ||
2001 | /* Check and possibly warn if two declarations have contradictory | |
2002 | attributes, such as always_inline vs. noinline. */ | |
2003 | ||
2004 | bool | |
2005 | diagnose_mismatched_attributes (tree olddecl, tree newdecl) | |
2006 | { | |
2007 | bool warned = false; | |
2008 | ||
2009 | tree a1 = lookup_attribute ("optimize", DECL_ATTRIBUTES (olddecl)); | |
2010 | tree a2 = lookup_attribute ("optimize", DECL_ATTRIBUTES (newdecl)); | |
2011 | /* An optimization attribute applied on a declaration after the | |
2012 | definition is likely not what the user wanted. */ | |
2013 | if (a2 != NULL_TREE | |
2014 | && DECL_SAVED_TREE (olddecl) != NULL_TREE | |
2015 | && (a1 == NULL_TREE || !attribute_list_equal (a1, a2))) | |
2016 | warned |= warning (OPT_Wattributes, | |
2017 | "optimization attribute on %qD follows " | |
2018 | "definition but the attribute doesn%'t match", | |
2019 | newdecl); | |
2020 | ||
2021 | /* Diagnose inline __attribute__ ((noinline)) which is silly. */ | |
2022 | if (DECL_DECLARED_INLINE_P (newdecl) | |
2023 | && DECL_UNINLINABLE (olddecl) | |
2024 | && lookup_attribute ("noinline", DECL_ATTRIBUTES (olddecl))) | |
2025 | warned |= warning (OPT_Wattributes, "inline declaration of %qD follows " | |
2026 | "declaration with attribute noinline", newdecl); | |
2027 | else if (DECL_DECLARED_INLINE_P (olddecl) | |
2028 | && DECL_UNINLINABLE (newdecl) | |
2029 | && lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl))) | |
2030 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
2031 | "noinline follows inline declaration ", newdecl); | |
2032 | else if (lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl)) | |
2033 | && lookup_attribute ("always_inline", DECL_ATTRIBUTES (olddecl))) | |
2034 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
2035 | "%qs follows declaration with attribute %qs", | |
2036 | newdecl, "noinline", "always_inline"); | |
2037 | else if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (newdecl)) | |
2038 | && lookup_attribute ("noinline", DECL_ATTRIBUTES (olddecl))) | |
2039 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
2040 | "%qs follows declaration with attribute %qs", | |
2041 | newdecl, "always_inline", "noinline"); | |
2042 | else if (lookup_attribute ("cold", DECL_ATTRIBUTES (newdecl)) | |
2043 | && lookup_attribute ("hot", DECL_ATTRIBUTES (olddecl))) | |
2044 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
2045 | "%qs follows declaration with attribute %qs", | |
2046 | newdecl, "cold", "hot"); | |
2047 | else if (lookup_attribute ("hot", DECL_ATTRIBUTES (newdecl)) | |
2048 | && lookup_attribute ("cold", DECL_ATTRIBUTES (olddecl))) | |
2049 | warned |= warning (OPT_Wattributes, "declaration of %q+D with attribute " | |
2050 | "%qs follows declaration with attribute %qs", | |
2051 | newdecl, "hot", "cold"); | |
2052 | return warned; | |
2053 | } | |
2054 | ||
2055 | /* Warn if signed left shift overflows. We don't warn | |
2056 | about left-shifting 1 into the sign bit in C++14; cf. | |
2057 | <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3367.html#1457> | |
2058 | LOC is a location of the shift; OP0 and OP1 are the operands. | |
2059 | Return true if an overflow is detected, false otherwise. */ | |
2060 | ||
2061 | bool | |
2062 | maybe_warn_shift_overflow (location_t loc, tree op0, tree op1) | |
2063 | { | |
2064 | if (TREE_CODE (op0) != INTEGER_CST | |
2065 | || TREE_CODE (op1) != INTEGER_CST) | |
2066 | return false; | |
2067 | ||
2068 | tree type0 = TREE_TYPE (op0); | |
2069 | unsigned int prec0 = TYPE_PRECISION (type0); | |
2070 | ||
2071 | /* Left-hand operand must be signed. */ | |
2072 | if (TYPE_UNSIGNED (type0)) | |
2073 | return false; | |
2074 | ||
2075 | unsigned int min_prec = (wi::min_precision (op0, SIGNED) | |
2076 | + TREE_INT_CST_LOW (op1)); | |
2077 | /* Handle the case of left-shifting 1 into the sign bit. | |
2078 | * However, shifting 1 _out_ of the sign bit, as in | |
2079 | * INT_MIN << 1, is considered an overflow. | |
2080 | */ | |
2081 | if (!tree_int_cst_sign_bit(op0) && min_prec == prec0 + 1) | |
2082 | { | |
2083 | /* Never warn for C++14 onwards. */ | |
2084 | if (cxx_dialect >= cxx14) | |
2085 | return false; | |
2086 | /* Otherwise only if -Wshift-overflow=2. But return | |
2087 | true to signal an overflow for the sake of integer | |
2088 | constant expressions. */ | |
2089 | if (warn_shift_overflow < 2) | |
2090 | return true; | |
2091 | } | |
2092 | ||
2093 | bool overflowed = min_prec > prec0; | |
2094 | if (overflowed && c_inhibit_evaluation_warnings == 0) | |
2095 | warning_at (loc, OPT_Wshift_overflow_, | |
2096 | "result of %qE requires %u bits to represent, " | |
2097 | "but %qT only has %u bits", | |
2098 | build2_loc (loc, LSHIFT_EXPR, type0, op0, op1), | |
2099 | min_prec, type0, prec0); | |
2100 | ||
2101 | return overflowed; | |
2102 | } | |
2103 | ||
2104 | /* Warn about boolean expression compared with an integer value different | |
2105 | from true/false. Warns also e.g. about "(i1 == i2) == 2". | |
2106 | LOC is the location of the comparison, CODE is its code, OP0 and OP1 | |
2107 | are the operands of the comparison. The caller must ensure that | |
2108 | either operand is a boolean expression. */ | |
2109 | ||
2110 | void | |
2111 | maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0, | |
2112 | tree op1) | |
2113 | { | |
2114 | if (TREE_CODE_CLASS (code) != tcc_comparison) | |
2115 | return; | |
2116 | ||
2117 | tree f, cst; | |
2118 | if (f = fold_for_warn (op0), | |
2119 | TREE_CODE (f) == INTEGER_CST) | |
2120 | cst = op0 = f; | |
2121 | else if (f = fold_for_warn (op1), | |
2122 | TREE_CODE (f) == INTEGER_CST) | |
2123 | cst = op1 = f; | |
2124 | else | |
2125 | return; | |
2126 | ||
2127 | if (!integer_zerop (cst) && !integer_onep (cst)) | |
2128 | { | |
2129 | int sign = (TREE_CODE (op0) == INTEGER_CST | |
2130 | ? tree_int_cst_sgn (cst) : -tree_int_cst_sgn (cst)); | |
2131 | if (code == EQ_EXPR | |
2132 | || ((code == GT_EXPR || code == GE_EXPR) && sign < 0) | |
2133 | || ((code == LT_EXPR || code == LE_EXPR) && sign > 0)) | |
2134 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2135 | "with boolean expression is always false", cst); | |
2136 | else | |
2137 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2138 | "with boolean expression is always true", cst); | |
2139 | } | |
2140 | else if (integer_zerop (cst) || integer_onep (cst)) | |
2141 | { | |
2142 | /* If the non-constant operand isn't of a boolean type, we | |
2143 | don't want to warn here. */ | |
2144 | tree noncst = TREE_CODE (op0) == INTEGER_CST ? op1 : op0; | |
2145 | /* Handle booleans promoted to integers. */ | |
2146 | if (bool_promoted_to_int_p (noncst)) | |
2147 | /* Warn. */; | |
2148 | else if (TREE_CODE (TREE_TYPE (noncst)) != BOOLEAN_TYPE | |
2149 | && !truth_value_p (TREE_CODE (noncst))) | |
2150 | return; | |
2151 | /* Do some magic to get the right diagnostics. */ | |
2152 | bool flag = TREE_CODE (op0) == INTEGER_CST; | |
2153 | flag = integer_zerop (cst) ? flag : !flag; | |
2154 | if ((code == GE_EXPR && !flag) || (code == LE_EXPR && flag)) | |
2155 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2156 | "with boolean expression is always true", cst); | |
2157 | else if ((code == LT_EXPR && !flag) || (code == GT_EXPR && flag)) | |
2158 | warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE " | |
2159 | "with boolean expression is always false", cst); | |
2160 | } | |
2161 | } |