1 /* Diagnostic routines shared by all languages that are variants of C.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>. */
22 #include "coretypes.h"
29 #include "diagnostic.h"
31 #include "stringpool.h"
34 #include "gcc-rich-location.h"
36 #include "c-family/c-indentation.h"
38 /* Print a warning if a constant expression had overflow in folding.
39 Invoke this function on every expression that the language
40 requires to be a constant expression.
41 Note the ANSI C standard says it is erroneous for a
42 constant expression to overflow. */
45 constant_expression_warning (tree value
)
47 if (warn_overflow
&& pedantic
48 && (TREE_CODE (value
) == INTEGER_CST
|| TREE_CODE (value
) == REAL_CST
49 || TREE_CODE (value
) == FIXED_CST
50 || TREE_CODE (value
) == VECTOR_CST
51 || TREE_CODE (value
) == COMPLEX_CST
)
52 && TREE_OVERFLOW (value
))
53 pedwarn (input_location
, OPT_Woverflow
, "overflow in constant expression");
56 /* The same as above but print an unconditional error. */
59 constant_expression_error (tree value
)
61 if ((TREE_CODE (value
) == INTEGER_CST
|| TREE_CODE (value
) == REAL_CST
62 || TREE_CODE (value
) == FIXED_CST
63 || TREE_CODE (value
) == VECTOR_CST
64 || TREE_CODE (value
) == COMPLEX_CST
)
65 && TREE_OVERFLOW (value
))
66 error ("overflow in constant expression");
69 /* Print a warning if an expression result VALUE had an overflow
70 in folding and its operands hadn't. EXPR, which may be null, is
71 the operand of the expression.
73 Invoke this function on every expression that
74 (1) appears in the source code, and
75 (2) is a constant expression that overflowed, and
76 (3) is not already checked by convert_and_check;
77 however, do not invoke this function on operands of explicit casts
78 or when the expression is the result of an operator and any operand
79 already overflowed. */
82 overflow_warning (location_t loc
, tree value
, tree expr
)
84 if (c_inhibit_evaluation_warnings
!= 0)
87 const char *warnfmt
= NULL
;
89 switch (TREE_CODE (value
))
93 ? G_("integer overflow in expression %qE of type %qT "
95 : G_("integer overflow in expression of type %qT "
101 ? G_ ("floating point overflow in expression %qE "
102 "of type %qT results in %qE")
103 : G_ ("floating point overflow in expression of type %qT "
109 ? G_("fixed-point overflow in expression %qE of type %qT "
111 : G_("fixed-point overflow in expression of type %qT "
117 ? G_("vector overflow in expression %qE of type %qT "
119 : G_("vector overflow in expression of type %qT "
124 if (TREE_CODE (TREE_REALPART (value
)) == INTEGER_CST
)
126 ? G_("complex integer overflow in expression %qE "
127 "of type %qT results in %qE")
128 : G_("complex integer overflow in expression of type %qT "
130 else if (TREE_CODE (TREE_REALPART (value
)) == REAL_CST
)
132 ? G_("complex floating point overflow in expression %qE "
133 "of type %qT results in %qE")
134 : G_("complex floating point overflow in expression "
135 "of type %qT results in %qE"));
145 warning_at (loc
, OPT_Woverflow
, warnfmt
, expr
, TREE_TYPE (expr
), value
);
147 warning_at (loc
, OPT_Woverflow
, warnfmt
, TREE_TYPE (value
), value
);
149 TREE_NO_WARNING (value
) = 1;
152 /* Helper function for walk_tree. Unwrap C_MAYBE_CONST_EXPRs in an expression
156 unwrap_c_maybe_const (tree
*tp
, int *walk_subtrees
, void *)
158 if (TREE_CODE (*tp
) == C_MAYBE_CONST_EXPR
)
160 *tp
= C_MAYBE_CONST_EXPR_EXPR (*tp
);
161 /* C_MAYBE_CONST_EXPRs don't nest. */
162 *walk_subtrees
= false;
167 /* Warn about uses of logical || / && operator in a context where it
168 is likely that the bitwise equivalent was intended by the
169 programmer. We have seen an expression in which CODE is a binary
170 operator used to combine expressions OP_LEFT and OP_RIGHT, which before folding
171 had CODE_LEFT and CODE_RIGHT, into an expression of type TYPE. */
174 warn_logical_operator (location_t location
, enum tree_code code
, tree type
,
175 enum tree_code code_left
, tree op_left
,
176 enum tree_code
ARG_UNUSED (code_right
), tree op_right
)
178 int or_op
= (code
== TRUTH_ORIF_EXPR
|| code
== TRUTH_OR_EXPR
);
179 int in0_p
, in1_p
, in_p
;
180 tree low0
, low1
, low
, high0
, high1
, high
, lhs
, rhs
, tem
;
181 bool strict_overflow_p
= false;
183 if (!warn_logical_op
)
186 if (code
!= TRUTH_ANDIF_EXPR
187 && code
!= TRUTH_AND_EXPR
188 && code
!= TRUTH_ORIF_EXPR
189 && code
!= TRUTH_OR_EXPR
)
192 /* We don't want to warn if either operand comes from a macro
193 expansion. ??? This doesn't work with e.g. NEGATE_EXPR yet;
195 if (from_macro_expansion_at (EXPR_LOCATION (op_left
))
196 || from_macro_expansion_at (EXPR_LOCATION (op_right
)))
199 /* Warn if &&/|| are being used in a context where it is
200 likely that the bitwise equivalent was intended by the
201 programmer. That is, an expression such as op && MASK
202 where op should not be any boolean expression, nor a
203 constant, and mask seems to be a non-boolean integer constant. */
204 if (TREE_CODE (op_right
) == CONST_DECL
)
205 /* An enumerator counts as a constant. */
206 op_right
= DECL_INITIAL (op_right
);
207 if (!truth_value_p (code_left
)
208 && INTEGRAL_TYPE_P (TREE_TYPE (op_left
))
209 && !CONSTANT_CLASS_P (op_left
)
210 && !TREE_NO_WARNING (op_left
)
211 && TREE_CODE (op_right
) == INTEGER_CST
212 && !integer_zerop (op_right
)
213 && !integer_onep (op_right
))
216 warning_at (location
, OPT_Wlogical_op
, "logical %<or%>"
217 " applied to non-boolean constant");
219 warning_at (location
, OPT_Wlogical_op
, "logical %<and%>"
220 " applied to non-boolean constant");
221 TREE_NO_WARNING (op_left
) = true;
225 /* We do not warn for constants because they are typical of macro
226 expansions that test for features. */
227 if (CONSTANT_CLASS_P (fold_for_warn (op_left
))
228 || CONSTANT_CLASS_P (fold_for_warn (op_right
)))
231 /* This warning only makes sense with logical operands. */
232 if (!(truth_value_p (TREE_CODE (op_left
))
233 || INTEGRAL_TYPE_P (TREE_TYPE (op_left
)))
234 || !(truth_value_p (TREE_CODE (op_right
))
235 || INTEGRAL_TYPE_P (TREE_TYPE (op_right
))))
238 /* The range computations only work with scalars. */
239 if (VECTOR_TYPE_P (TREE_TYPE (op_left
))
240 || VECTOR_TYPE_P (TREE_TYPE (op_right
)))
243 /* We first test whether either side separately is trivially true
244 (with OR) or trivially false (with AND). If so, do not warn.
245 This is a common idiom for testing ranges of data types in
247 op_left
= unshare_expr (op_left
);
248 walk_tree_without_duplicates (&op_left
, unwrap_c_maybe_const
, NULL
);
249 lhs
= make_range (op_left
, &in0_p
, &low0
, &high0
, &strict_overflow_p
);
253 /* If this is an OR operation, invert both sides; now, the result
254 should be always false to get a warning. */
258 tem
= build_range_check (UNKNOWN_LOCATION
, type
, lhs
, in0_p
, low0
, high0
);
259 if (tem
&& integer_zerop (tem
))
262 op_right
= unshare_expr (op_right
);
263 walk_tree_without_duplicates (&op_right
, unwrap_c_maybe_const
, NULL
);
264 rhs
= make_range (op_right
, &in1_p
, &low1
, &high1
, &strict_overflow_p
);
268 /* If this is an OR operation, invert both sides; now, the result
269 should be always false to get a warning. */
273 tem
= build_range_check (UNKNOWN_LOCATION
, type
, rhs
, in1_p
, low1
, high1
);
274 if (tem
&& integer_zerop (tem
))
277 /* If both expressions have the same operand, if we can merge the
279 if (operand_equal_p (lhs
, rhs
, 0)
280 && merge_ranges (&in_p
, &low
, &high
, in0_p
, low0
, high0
,
283 tem
= build_range_check (UNKNOWN_LOCATION
, type
, lhs
, in_p
, low
, high
);
284 /* ... and if the range test is always false, then warn. */
285 if (tem
&& integer_zerop (tem
))
288 warning_at (location
, OPT_Wlogical_op
,
289 "logical %<or%> of collectively exhaustive tests is "
292 warning_at (location
, OPT_Wlogical_op
,
293 "logical %<and%> of mutually exclusive tests is "
296 /* Or warn if the operands have exactly the same range, e.g.
298 else if (tree_int_cst_equal (low0
, low1
)
299 && tree_int_cst_equal (high0
, high1
))
302 warning_at (location
, OPT_Wlogical_op
,
303 "logical %<or%> of equal expressions");
305 warning_at (location
, OPT_Wlogical_op
,
306 "logical %<and%> of equal expressions");
311 /* Helper function for warn_tautological_cmp. Look for ARRAY_REFs
312 with constant indices. */
315 find_array_ref_with_const_idx_r (tree
*expr_p
, int *, void *)
319 if ((TREE_CODE (expr
) == ARRAY_REF
320 || TREE_CODE (expr
) == ARRAY_RANGE_REF
)
321 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
)
322 return integer_type_node
;
327 /* Subroutine of warn_tautological_cmp. Warn about bitwise comparison
328 that always evaluate to true or false. LOC is the location of the
329 ==/!= comparison specified by CODE; LHS and RHS are the usual operands
330 of this comparison. */
333 warn_tautological_bitwise_comparison (location_t loc
, tree_code code
,
336 if (code
!= EQ_EXPR
&& code
!= NE_EXPR
)
339 /* Extract the operands from e.g. (x & 8) == 4. */
342 if ((TREE_CODE (lhs
) == BIT_AND_EXPR
343 || TREE_CODE (lhs
) == BIT_IOR_EXPR
)
344 && TREE_CODE (rhs
) == INTEGER_CST
)
345 bitop
= lhs
, cst
= rhs
;
346 else if ((TREE_CODE (rhs
) == BIT_AND_EXPR
347 || TREE_CODE (rhs
) == BIT_IOR_EXPR
)
348 && TREE_CODE (lhs
) == INTEGER_CST
)
349 bitop
= rhs
, cst
= lhs
;
354 if (TREE_CODE (TREE_OPERAND (bitop
, 0)) == INTEGER_CST
)
355 bitopcst
= TREE_OPERAND (bitop
, 0);
356 else if (TREE_CODE (TREE_OPERAND (bitop
, 1)) == INTEGER_CST
)
357 bitopcst
= TREE_OPERAND (bitop
, 1);
361 /* Note that the two operands are from before the usual integer
362 conversions, so their types might not be the same.
363 Use the larger of the two precisions and ignore bits outside
365 int prec
= MAX (TYPE_PRECISION (TREE_TYPE (cst
)),
366 TYPE_PRECISION (TREE_TYPE (bitopcst
)));
368 wide_int bitopcstw
= wi::to_wide (bitopcst
, prec
);
369 wide_int cstw
= wi::to_wide (cst
, prec
);
372 if (TREE_CODE (bitop
) == BIT_AND_EXPR
)
373 res
= bitopcstw
& cstw
;
375 res
= bitopcstw
| cstw
;
377 /* For BIT_AND only warn if (CST2 & CST1) != CST1, and
378 for BIT_OR only if (CST2 | CST1) != CST1. */
383 warning_at (loc
, OPT_Wtautological_compare
,
384 "bitwise comparison always evaluates to false");
386 warning_at (loc
, OPT_Wtautological_compare
,
387 "bitwise comparison always evaluates to true");
390 /* Warn if a self-comparison always evaluates to true or false. LOC
391 is the location of the comparison with code CODE, LHS and RHS are
392 operands of the comparison. */
395 warn_tautological_cmp (location_t loc
, enum tree_code code
, tree lhs
, tree rhs
)
397 if (TREE_CODE_CLASS (code
) != tcc_comparison
)
400 /* Don't warn for various macro expansions. */
401 if (from_macro_expansion_at (loc
)
402 || from_macro_expansion_at (EXPR_LOCATION (lhs
))
403 || from_macro_expansion_at (EXPR_LOCATION (rhs
)))
406 warn_tautological_bitwise_comparison (loc
, code
, lhs
, rhs
);
408 /* We do not warn for constants because they are typical of macro
409 expansions that test for features, sizeof, and similar. */
410 if (CONSTANT_CLASS_P (fold_for_warn (lhs
))
411 || CONSTANT_CLASS_P (fold_for_warn (rhs
)))
414 /* Don't warn for e.g.
417 if (n == (long) n) ...
419 if ((CONVERT_EXPR_P (lhs
) || TREE_CODE (lhs
) == NON_LVALUE_EXPR
)
420 || (CONVERT_EXPR_P (rhs
) || TREE_CODE (rhs
) == NON_LVALUE_EXPR
))
423 /* Don't warn if either LHS or RHS has an IEEE floating-point type.
424 It could be a NaN, and NaN never compares equal to anything, even
426 if (FLOAT_TYPE_P (TREE_TYPE (lhs
)) || FLOAT_TYPE_P (TREE_TYPE (rhs
)))
429 if (operand_equal_p (lhs
, rhs
, 0))
431 /* Don't warn about array references with constant indices;
432 these are likely to come from a macro. */
433 if (walk_tree_without_duplicates (&lhs
, find_array_ref_with_const_idx_r
,
436 const bool always_true
= (code
== EQ_EXPR
|| code
== LE_EXPR
437 || code
== GE_EXPR
|| code
== UNLE_EXPR
438 || code
== UNGE_EXPR
|| code
== UNEQ_EXPR
);
440 warning_at (loc
, OPT_Wtautological_compare
,
441 "self-comparison always evaluates to true");
443 warning_at (loc
, OPT_Wtautological_compare
,
444 "self-comparison always evaluates to false");
448 /* Return true iff EXPR only contains boolean operands, or comparisons. */
451 expr_has_boolean_operands_p (tree expr
)
455 if (CONVERT_EXPR_P (expr
))
456 return bool_promoted_to_int_p (expr
);
457 else if (UNARY_CLASS_P (expr
))
458 return expr_has_boolean_operands_p (TREE_OPERAND (expr
, 0));
459 else if (BINARY_CLASS_P (expr
))
460 return (expr_has_boolean_operands_p (TREE_OPERAND (expr
, 0))
461 && expr_has_boolean_operands_p (TREE_OPERAND (expr
, 1)));
462 else if (COMPARISON_CLASS_P (expr
))
468 /* Warn about logical not used on the left hand side operand of a comparison.
469 This function assumes that the LHS is inside of TRUTH_NOT_EXPR.
470 Do not warn if RHS is of a boolean type, a logical operator, or
474 warn_logical_not_parentheses (location_t location
, enum tree_code code
,
477 if (TREE_CODE_CLASS (code
) != tcc_comparison
478 || TREE_TYPE (rhs
) == NULL_TREE
479 || TREE_CODE (TREE_TYPE (rhs
)) == BOOLEAN_TYPE
480 || truth_value_p (TREE_CODE (rhs
)))
483 /* Don't warn for expression like !x == ~(bool1 | bool2). */
484 if (expr_has_boolean_operands_p (rhs
))
487 /* Don't warn for !x == 0 or !y != 0, those are equivalent to
488 !(x == 0) or !(y != 0). */
489 if ((code
== EQ_EXPR
|| code
== NE_EXPR
)
490 && integer_zerop (rhs
))
493 if (warning_at (location
, OPT_Wlogical_not_parentheses
,
494 "logical not is only applied to the left hand side of "
496 && EXPR_HAS_LOCATION (lhs
))
498 location_t lhs_loc
= EXPR_LOCATION (lhs
);
499 rich_location
richloc (line_table
, lhs_loc
);
500 richloc
.add_fixit_insert_before (lhs_loc
, "(");
501 richloc
.add_fixit_insert_after (lhs_loc
, ")");
502 inform (&richloc
, "add parentheses around left hand side "
503 "expression to silence this warning");
507 /* Warn if EXP contains any computations whose results are not used.
508 Return true if a warning is printed; false otherwise. LOCUS is the
509 (potential) location of the expression. */
512 warn_if_unused_value (const_tree exp
, location_t locus
)
515 if (TREE_USED (exp
) || TREE_NO_WARNING (exp
))
518 /* Don't warn about void constructs. This includes casting to void,
519 void function calls, and statement expressions with a final cast
521 if (VOID_TYPE_P (TREE_TYPE (exp
)))
524 if (EXPR_HAS_LOCATION (exp
))
525 locus
= EXPR_LOCATION (exp
);
527 switch (TREE_CODE (exp
))
529 case PREINCREMENT_EXPR
:
530 case POSTINCREMENT_EXPR
:
531 case PREDECREMENT_EXPR
:
532 case POSTDECREMENT_EXPR
:
543 /* For a binding, warn if no side effect within it. */
544 exp
= BIND_EXPR_BODY (exp
);
548 case NON_LVALUE_EXPR
:
550 exp
= TREE_OPERAND (exp
, 0);
553 case TRUTH_ORIF_EXPR
:
554 case TRUTH_ANDIF_EXPR
:
555 /* In && or ||, warn if 2nd operand has no side effect. */
556 exp
= TREE_OPERAND (exp
, 1);
560 if (warn_if_unused_value (TREE_OPERAND (exp
, 0), locus
))
562 /* Let people do `(foo (), 0)' without a warning. */
563 if (TREE_CONSTANT (TREE_OPERAND (exp
, 1)))
565 exp
= TREE_OPERAND (exp
, 1);
569 /* If this is an expression with side effects, don't warn; this
570 case commonly appears in macro expansions. */
571 if (TREE_SIDE_EFFECTS (exp
))
576 /* Don't warn about automatic dereferencing of references, since
577 the user cannot control it. */
578 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp
, 0))) == REFERENCE_TYPE
)
580 exp
= TREE_OPERAND (exp
, 0);
586 /* Referencing a volatile value is a side effect, so don't warn. */
587 if ((DECL_P (exp
) || REFERENCE_CLASS_P (exp
))
588 && TREE_THIS_VOLATILE (exp
))
591 /* If this is an expression which has no operands, there is no value
592 to be unused. There are no such language-independent codes,
593 but front ends may define such. */
594 if (EXPRESSION_CLASS_P (exp
) && TREE_OPERAND_LENGTH (exp
) == 0)
598 return warning_at (locus
, OPT_Wunused_value
, "value computed is not used");
602 /* Print a warning about casts that might indicate violation of strict
603 aliasing rules if -Wstrict-aliasing is used and strict aliasing
604 mode is in effect. LOC is the location of the expression being
605 cast, EXPR might be from inside it. TYPE is the type we're casting
609 strict_aliasing_warning (location_t loc
, tree type
, tree expr
)
611 if (loc
== UNKNOWN_LOCATION
)
612 loc
= input_location
;
614 /* Strip pointer conversion chains and get to the correct original type. */
616 tree otype
= TREE_TYPE (expr
);
618 if (!(flag_strict_aliasing
619 && POINTER_TYPE_P (type
)
620 && POINTER_TYPE_P (otype
)
621 && !VOID_TYPE_P (TREE_TYPE (type
)))
622 /* If the type we are casting to is a ref-all pointer
623 dereferencing it is always valid. */
624 || TYPE_REF_CAN_ALIAS_ALL (type
))
627 if ((warn_strict_aliasing
> 1) && TREE_CODE (expr
) == ADDR_EXPR
628 && (DECL_P (TREE_OPERAND (expr
, 0))
629 || handled_component_p (TREE_OPERAND (expr
, 0))))
631 /* Casting the address of an object to non void pointer. Warn
632 if the cast breaks type based aliasing. */
633 if (!COMPLETE_TYPE_P (TREE_TYPE (type
)) && warn_strict_aliasing
== 2)
635 warning_at (loc
, OPT_Wstrict_aliasing
,
636 "type-punning to incomplete type "
637 "might break strict-aliasing rules");
642 /* warn_strict_aliasing >= 3. This includes the default (3).
643 Only warn if the cast is dereferenced immediately. */
645 = get_alias_set (TREE_TYPE (TREE_OPERAND (expr
, 0)));
646 alias_set_type set2
= get_alias_set (TREE_TYPE (type
));
650 && !alias_set_subset_of (set2
, set1
)
651 && !alias_sets_conflict_p (set1
, set2
))
653 warning_at (loc
, OPT_Wstrict_aliasing
,
654 "dereferencing type-punned "
655 "pointer will break strict-aliasing rules");
658 else if (warn_strict_aliasing
== 2
659 && !alias_sets_must_conflict_p (set1
, set2
))
661 warning_at (loc
, OPT_Wstrict_aliasing
,
662 "dereferencing type-punned "
663 "pointer might break strict-aliasing rules");
668 else if ((warn_strict_aliasing
== 1) && !VOID_TYPE_P (TREE_TYPE (otype
)))
670 /* At this level, warn for any conversions, even if an address is
671 not taken in the same statement. This will likely produce many
672 false positives, but could be useful to pinpoint problems that
673 are not revealed at higher levels. */
674 alias_set_type set1
= get_alias_set (TREE_TYPE (otype
));
675 alias_set_type set2
= get_alias_set (TREE_TYPE (type
));
676 if (!COMPLETE_TYPE_P (type
)
677 || !alias_sets_must_conflict_p (set1
, set2
))
679 warning_at (loc
, OPT_Wstrict_aliasing
,
680 "dereferencing type-punned "
681 "pointer might break strict-aliasing rules");
689 /* Warn about memset (&a, 0, sizeof (&a)); and similar mistakes with
690 sizeof as last operand of certain builtins. */
693 sizeof_pointer_memaccess_warning (location_t
*sizeof_arg_loc
, tree callee
,
694 vec
<tree
, va_gc
> *params
, tree
*sizeof_arg
,
695 bool (*comp_types
) (tree
, tree
))
697 tree type
, dest
= NULL_TREE
, src
= NULL_TREE
, tem
;
698 bool strop
= false, cmp
= false;
699 unsigned int idx
= ~0;
702 if (TREE_CODE (callee
) != FUNCTION_DECL
703 || DECL_BUILT_IN_CLASS (callee
) != BUILT_IN_NORMAL
704 || vec_safe_length (params
) <= 1)
707 enum built_in_function fncode
= DECL_FUNCTION_CODE (callee
);
710 case BUILT_IN_STRNCMP
:
711 case BUILT_IN_STRNCASECMP
:
714 case BUILT_IN_STRNCPY
:
715 case BUILT_IN_STRNCPY_CHK
:
716 case BUILT_IN_STRNCAT
:
717 case BUILT_IN_STRNCAT_CHK
:
718 case BUILT_IN_STPNCPY
:
719 case BUILT_IN_STPNCPY_CHK
:
722 case BUILT_IN_MEMCPY
:
723 case BUILT_IN_MEMCPY_CHK
:
724 case BUILT_IN_MEMMOVE
:
725 case BUILT_IN_MEMMOVE_CHK
:
726 if (params
->length () < 3)
733 if (params
->length () < 3)
739 case BUILT_IN_MEMCMP
:
741 if (params
->length () < 3)
748 case BUILT_IN_MEMSET
:
749 case BUILT_IN_MEMSET_CHK
:
750 if (params
->length () < 3)
759 case BUILT_IN_STRNDUP
:
764 case BUILT_IN_MEMCHR
:
765 if (params
->length () < 3)
770 case BUILT_IN_SNPRINTF
:
771 case BUILT_IN_SNPRINTF_CHK
:
772 case BUILT_IN_VSNPRINTF
:
773 case BUILT_IN_VSNPRINTF_CHK
:
785 if (sizeof_arg
[idx
] == NULL
|| sizeof_arg
[idx
] == error_mark_node
)
788 type
= TYPE_P (sizeof_arg
[idx
])
789 ? sizeof_arg
[idx
] : TREE_TYPE (sizeof_arg
[idx
]);
791 if (!POINTER_TYPE_P (type
))
793 /* The argument type may be an array. Diagnose bounded string
794 copy functions that specify the bound in terms of the source
795 argument rather than the destination. */
796 if (strop
&& !cmp
&& fncode
!= BUILT_IN_STRNDUP
&& src
)
798 tem
= tree_strip_nop_conversions (src
);
799 if (TREE_CODE (tem
) == ADDR_EXPR
)
800 tem
= TREE_OPERAND (tem
, 0);
801 if (operand_equal_p (tem
, sizeof_arg
[idx
], OEP_ADDRESS_OF
))
802 warning_at (sizeof_arg_loc
[idx
], OPT_Wsizeof_pointer_memaccess
,
803 "argument to %<sizeof%> in %qD call is the same "
804 "expression as the source; did you mean to use "
805 "the size of the destination?",
813 && (tem
= tree_strip_nop_conversions (dest
))
814 && POINTER_TYPE_P (TREE_TYPE (tem
))
815 && comp_types (TREE_TYPE (TREE_TYPE (tem
)), type
))
819 && (tem
= tree_strip_nop_conversions (src
))
820 && POINTER_TYPE_P (TREE_TYPE (tem
))
821 && comp_types (TREE_TYPE (TREE_TYPE (tem
)), type
))
824 loc
= sizeof_arg_loc
[idx
];
828 if (!TYPE_P (sizeof_arg
[idx
])
829 && operand_equal_p (dest
, sizeof_arg
[idx
], 0)
830 && comp_types (TREE_TYPE (dest
), type
))
832 if (TREE_CODE (sizeof_arg
[idx
]) == ADDR_EXPR
&& !strop
)
833 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
834 "argument to %<sizeof%> in %qD call is the same "
835 "expression as the destination; did you mean to "
836 "remove the addressof?", callee
);
837 else if ((TYPE_PRECISION (TREE_TYPE (type
))
838 == TYPE_PRECISION (char_type_node
))
840 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
841 "argument to %<sizeof%> in %qD call is the same "
842 "expression as the destination; did you mean to "
843 "provide an explicit length?", callee
);
845 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
846 "argument to %<sizeof%> in %qD call is the same "
847 "expression as the destination; did you mean to "
848 "dereference it?", callee
);
852 if (POINTER_TYPE_P (TREE_TYPE (dest
))
854 && comp_types (TREE_TYPE (dest
), type
)
855 && !VOID_TYPE_P (TREE_TYPE (type
)))
857 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
858 "argument to %<sizeof%> in %qD call is the same "
859 "pointer type %qT as the destination; expected %qT "
860 "or an explicit length", callee
, TREE_TYPE (dest
),
861 TREE_TYPE (TREE_TYPE (dest
)));
868 if (!TYPE_P (sizeof_arg
[idx
])
869 && operand_equal_p (src
, sizeof_arg
[idx
], 0)
870 && comp_types (TREE_TYPE (src
), type
))
872 if (TREE_CODE (sizeof_arg
[idx
]) == ADDR_EXPR
&& !strop
)
873 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
874 "argument to %<sizeof%> in %qD call is the same "
875 "expression as the source; did you mean to "
876 "remove the addressof?", callee
);
877 else if ((TYPE_PRECISION (TREE_TYPE (type
))
878 == TYPE_PRECISION (char_type_node
))
880 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
881 "argument to %<sizeof%> in %qD call is the same "
882 "expression as the source; did you mean to "
883 "provide an explicit length?", callee
);
885 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
886 "argument to %<sizeof%> in %qD call is the same "
887 "expression as the source; did you mean to "
888 "dereference it?", callee
);
892 if (POINTER_TYPE_P (TREE_TYPE (src
))
894 && comp_types (TREE_TYPE (src
), type
)
895 && !VOID_TYPE_P (TREE_TYPE (type
)))
897 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
898 "argument to %<sizeof%> in %qD call is the same "
899 "pointer type %qT as the source; expected %qT "
900 "or an explicit length", callee
, TREE_TYPE (src
),
901 TREE_TYPE (TREE_TYPE (src
)));
908 if (!TYPE_P (sizeof_arg
[idx
])
909 && operand_equal_p (dest
, sizeof_arg
[idx
], 0)
910 && comp_types (TREE_TYPE (dest
), type
))
912 if (TREE_CODE (sizeof_arg
[idx
]) == ADDR_EXPR
&& !strop
)
913 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
914 "argument to %<sizeof%> in %qD call is the same "
915 "expression as the first source; did you mean to "
916 "remove the addressof?", callee
);
917 else if ((TYPE_PRECISION (TREE_TYPE (type
))
918 == TYPE_PRECISION (char_type_node
))
920 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
921 "argument to %<sizeof%> in %qD call is the same "
922 "expression as the first source; did you mean to "
923 "provide an explicit length?", callee
);
925 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
926 "argument to %<sizeof%> in %qD call is the same "
927 "expression as the first source; did you mean to "
928 "dereference it?", callee
);
932 if (POINTER_TYPE_P (TREE_TYPE (dest
))
934 && comp_types (TREE_TYPE (dest
), type
)
935 && !VOID_TYPE_P (TREE_TYPE (type
)))
937 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
938 "argument to %<sizeof%> in %qD call is the same "
939 "pointer type %qT as the first source; expected %qT "
940 "or an explicit length", callee
, TREE_TYPE (dest
),
941 TREE_TYPE (TREE_TYPE (dest
)));
948 if (!TYPE_P (sizeof_arg
[idx
])
949 && operand_equal_p (src
, sizeof_arg
[idx
], 0)
950 && comp_types (TREE_TYPE (src
), type
))
952 if (TREE_CODE (sizeof_arg
[idx
]) == ADDR_EXPR
&& !strop
)
953 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
954 "argument to %<sizeof%> in %qD call is the same "
955 "expression as the second source; did you mean to "
956 "remove the addressof?", callee
);
957 else if ((TYPE_PRECISION (TREE_TYPE (type
))
958 == TYPE_PRECISION (char_type_node
))
960 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
961 "argument to %<sizeof%> in %qD call is the same "
962 "expression as the second source; did you mean to "
963 "provide an explicit length?", callee
);
965 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
966 "argument to %<sizeof%> in %qD call is the same "
967 "expression as the second source; did you mean to "
968 "dereference it?", callee
);
972 if (POINTER_TYPE_P (TREE_TYPE (src
))
974 && comp_types (TREE_TYPE (src
), type
)
975 && !VOID_TYPE_P (TREE_TYPE (type
)))
977 warning_at (loc
, OPT_Wsizeof_pointer_memaccess
,
978 "argument to %<sizeof%> in %qD call is the same "
979 "pointer type %qT as the second source; expected %qT "
980 "or an explicit length", callee
, TREE_TYPE (src
),
981 TREE_TYPE (TREE_TYPE (src
)));
988 /* Warn for unlikely, improbable, or stupid DECL declarations
992 check_main_parameter_types (tree decl
)
994 function_args_iterator iter
;
998 FOREACH_FUNCTION_ARGS (TREE_TYPE (decl
), type
, iter
)
1000 /* XXX void_type_node belies the abstraction. */
1001 if (type
== void_type_node
|| type
== error_mark_node
)
1005 if (TYPE_ATOMIC (t
))
1006 pedwarn (input_location
, OPT_Wmain
,
1007 "%<_Atomic%>-qualified parameter type %qT of %q+D",
1009 while (POINTER_TYPE_P (t
))
1012 if (TYPE_ATOMIC (t
))
1013 pedwarn (input_location
, OPT_Wmain
,
1014 "%<_Atomic%>-qualified parameter type %qT of %q+D",
1022 if (TYPE_MAIN_VARIANT (type
) != integer_type_node
)
1023 pedwarn (input_location
, OPT_Wmain
,
1024 "first argument of %q+D should be %<int%>", decl
);
1028 if (TREE_CODE (type
) != POINTER_TYPE
1029 || TREE_CODE (TREE_TYPE (type
)) != POINTER_TYPE
1030 || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type
)))
1032 pedwarn (input_location
, OPT_Wmain
,
1033 "second argument of %q+D should be %<char **%>", decl
);
1037 if (TREE_CODE (type
) != POINTER_TYPE
1038 || TREE_CODE (TREE_TYPE (type
)) != POINTER_TYPE
1039 || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (type
)))
1041 pedwarn (input_location
, OPT_Wmain
,
1042 "third argument of %q+D should probably be "
1043 "%<char **%>", decl
);
1048 /* It is intentional that this message does not mention the third
1049 argument because it's only mentioned in an appendix of the
1051 if (argct
> 0 && (argct
< 2 || argct
> 3))
1052 pedwarn (input_location
, OPT_Wmain
,
1053 "%q+D takes only zero or two arguments", decl
);
1055 if (stdarg_p (TREE_TYPE (decl
)))
1056 pedwarn (input_location
, OPT_Wmain
,
1057 "%q+D declared as variadic function", decl
);
1060 /* Warns if the conversion of EXPR to TYPE may alter a value.
1061 This is a helper function for warnings_for_convert_and_check. */
1064 conversion_warning (location_t loc
, tree type
, tree expr
, tree result
)
1066 tree expr_type
= TREE_TYPE (expr
);
1067 enum conversion_safety conversion_kind
;
1069 if (!warn_conversion
&& !warn_sign_conversion
&& !warn_float_conversion
)
1072 /* This may happen, because for LHS op= RHS we preevaluate
1073 RHS and create C_MAYBE_CONST_EXPR <SAVE_EXPR <RHS>>, which
1074 means we could no longer see the code of the EXPR. */
1075 if (TREE_CODE (expr
) == C_MAYBE_CONST_EXPR
)
1076 expr
= C_MAYBE_CONST_EXPR_EXPR (expr
);
1077 if (TREE_CODE (expr
) == SAVE_EXPR
)
1078 expr
= TREE_OPERAND (expr
, 0);
1080 switch (TREE_CODE (expr
))
1088 case TRUTH_ANDIF_EXPR
:
1089 case TRUTH_ORIF_EXPR
:
1090 case TRUTH_AND_EXPR
:
1092 case TRUTH_XOR_EXPR
:
1093 case TRUTH_NOT_EXPR
:
1094 /* Conversion from boolean to a signed:1 bit-field (which only
1095 can hold the values 0 and -1) doesn't lose information - but
1096 it does change the value. */
1097 if (TYPE_PRECISION (type
) == 1 && !TYPE_UNSIGNED (type
))
1098 warning_at (loc
, OPT_Wconversion
,
1099 "conversion to %qT from boolean expression", type
);
1106 conversion_kind
= unsafe_conversion_p (loc
, type
, expr
, result
, true);
1108 if (conversion_kind
== UNSAFE_REAL
)
1109 warnopt
= OPT_Wfloat_conversion
;
1110 else if (conversion_kind
)
1111 warnopt
= OPT_Wconversion
;
1115 if (TREE_CODE_CLASS (TREE_CODE (result
)) == tcc_constant
)
1116 warning_at (loc
, warnopt
,
1117 "conversion from %qT to %qT changes value from %qE to %qE",
1118 expr_type
, type
, expr
, result
);
1120 warning_at (loc
, warnopt
,
1121 "conversion from %qT to %qT changes the value of %qE",
1122 expr_type
, type
, expr
);
1127 /* In case of COND_EXPR, we do not care about the type of
1128 COND_EXPR, only about the conversion of each operand. */
1129 tree op1
= TREE_OPERAND (expr
, 1);
1130 tree op2
= TREE_OPERAND (expr
, 2);
1132 conversion_warning (loc
, type
, op1
, result
);
1133 conversion_warning (loc
, type
, op2
, result
);
1137 default: /* 'expr' is not a constant. */
1138 conversion_kind
= unsafe_conversion_p (loc
, type
, expr
, result
, true);
1139 if (conversion_kind
== UNSAFE_IMAGINARY
)
1140 warning_at (loc
, OPT_Wconversion
,
1141 "conversion from %qT to %qT discards imaginary component",
1146 if (conversion_kind
== UNSAFE_REAL
)
1147 warnopt
= OPT_Wfloat_conversion
;
1148 else if (conversion_kind
)
1149 warnopt
= OPT_Wconversion
;
1152 warning_at (loc
, warnopt
,
1153 "conversion from %qT to %qT may change value",
1159 /* Produce warnings after a conversion. RESULT is the result of
1160 converting EXPR to TYPE. This is a helper function for
1161 convert_and_check and cp_convert_and_check. */
1164 warnings_for_convert_and_check (location_t loc
, tree type
, tree expr
,
1167 loc
= expansion_point_location_if_in_system_header (loc
);
1169 bool cst
= TREE_CODE_CLASS (TREE_CODE (result
)) == tcc_constant
;
1171 tree exprtype
= TREE_TYPE (expr
);
1173 if (TREE_CODE (expr
) == INTEGER_CST
1174 && (TREE_CODE (type
) == INTEGER_TYPE
1175 || TREE_CODE (type
) == ENUMERAL_TYPE
)
1176 && !int_fits_type_p (expr
, type
))
1178 /* Do not diagnose overflow in a constant expression merely
1179 because a conversion overflowed. */
1180 if (TREE_OVERFLOW (result
))
1181 TREE_OVERFLOW (result
) = TREE_OVERFLOW (expr
);
1183 if (TYPE_UNSIGNED (type
))
1185 /* This detects cases like converting -129 or 256 to
1187 if (!int_fits_type_p (expr
, c_common_signed_type (type
)))
1190 warning_at (loc
, OPT_Woverflow
,
1191 (TYPE_UNSIGNED (exprtype
)
1192 ? G_("conversion from %qT to %qT "
1193 "changes value from %qE to %qE")
1194 : G_("unsigned conversion from %qT to %qT "
1195 "changes value from %qE to %qE")),
1196 exprtype
, type
, expr
, result
);
1198 warning_at (loc
, OPT_Woverflow
,
1199 (TYPE_UNSIGNED (exprtype
)
1200 ? G_("conversion from %qT to %qT "
1201 "changes the value of %qE")
1202 : G_("unsigned conversion from %qT to %qT "
1203 "changes the value of %qE")),
1204 exprtype
, type
, expr
);
1207 conversion_warning (loc
, type
, expr
, result
);
1209 else if (!int_fits_type_p (expr
, c_common_unsigned_type (type
)))
1212 warning_at (loc
, OPT_Woverflow
,
1213 "overflow in conversion from %qT to %qT "
1214 "changes value from %qE to %qE",
1215 exprtype
, type
, expr
, result
);
1217 warning_at (loc
, OPT_Woverflow
,
1218 "overflow in conversion from %qT to %qT "
1219 "changes the value of %qE",
1220 exprtype
, type
, expr
);
1222 /* No warning for converting 0x80000000 to int. */
1224 && (TREE_CODE (exprtype
) != INTEGER_TYPE
1225 || TYPE_PRECISION (exprtype
)
1226 != TYPE_PRECISION (type
)))
1229 warning_at (loc
, OPT_Woverflow
,
1230 "overflow in conversion from %qT to %qT "
1231 "changes value from %qE to %qE",
1232 exprtype
, type
, expr
, result
);
1234 warning_at (loc
, OPT_Woverflow
,
1235 "overflow in conversion from %qT to %qT "
1236 "changes the value of %qE",
1237 exprtype
, type
, expr
);
1240 conversion_warning (loc
, type
, expr
, result
);
1242 else if ((TREE_CODE (result
) == INTEGER_CST
1243 || TREE_CODE (result
) == FIXED_CST
) && TREE_OVERFLOW (result
))
1246 warning_at (loc
, OPT_Woverflow
,
1247 "overflow in conversion from %qT to %qT "
1248 "changes value from %qE to %qE",
1249 exprtype
, type
, expr
, result
);
1251 warning_at (loc
, OPT_Woverflow
,
1252 "overflow in conversion from %qT to %qT "
1253 "changes the value of %qE",
1254 exprtype
, type
, expr
);
1257 conversion_warning (loc
, type
, expr
, result
);
1260 /* Subroutines of c_do_switch_warnings, called via splay_tree_foreach.
1261 Used to verify that case values match up with enumerator values. */
1264 match_case_to_enum_1 (tree key
, tree type
, tree label
)
1266 /* Avoid warning about enums that have no enumerators. */
1267 if (TYPE_VALUES (type
) == NULL_TREE
)
1270 char buf
[WIDE_INT_PRINT_BUFFER_SIZE
];
1272 if (tree_fits_uhwi_p (key
))
1273 print_dec (wi::to_wide (key
), buf
, UNSIGNED
);
1274 else if (tree_fits_shwi_p (key
))
1275 print_dec (wi::to_wide (key
), buf
, SIGNED
);
1277 print_hex (wi::to_wide (key
), buf
);
1279 if (TYPE_NAME (type
) == NULL_TREE
)
1280 warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label
)),
1281 warn_switch
? OPT_Wswitch
: OPT_Wswitch_enum
,
1282 "case value %qs not in enumerated type",
1285 warning_at (DECL_SOURCE_LOCATION (CASE_LABEL (label
)),
1286 warn_switch
? OPT_Wswitch
: OPT_Wswitch_enum
,
1287 "case value %qs not in enumerated type %qT",
1291 /* Subroutine of c_do_switch_warnings, called via splay_tree_foreach.
1292 Used to verify that case values match up with enumerator values. */
1295 match_case_to_enum (splay_tree_node node
, void *data
)
1297 tree label
= (tree
) node
->value
;
1298 tree type
= (tree
) data
;
1300 /* Skip default case. */
1301 if (!CASE_LOW (label
))
1304 /* If CASE_LOW_SEEN is not set, that means CASE_LOW did not appear
1305 when we did our enum->case scan. Reset our scratch bit after. */
1306 if (!CASE_LOW_SEEN (label
))
1307 match_case_to_enum_1 (CASE_LOW (label
), type
, label
);
1309 CASE_LOW_SEEN (label
) = 0;
1311 /* If CASE_HIGH is non-null, we have a range. If CASE_HIGH_SEEN is
1312 not set, that means that CASE_HIGH did not appear when we did our
1313 enum->case scan. Reset our scratch bit after. */
1314 if (CASE_HIGH (label
))
1316 if (!CASE_HIGH_SEEN (label
))
1317 match_case_to_enum_1 (CASE_HIGH (label
), type
, label
);
1319 CASE_HIGH_SEEN (label
) = 0;
1325 /* Handle -Wswitch*. Called from the front end after parsing the
1326 switch construct. */
1327 /* ??? Should probably be somewhere generic, since other languages
1328 besides C and C++ would want this. At the moment, however, C/C++
1329 are the only tree-ssa languages that support enumerations at all,
1330 so the point is moot. */
1333 c_do_switch_warnings (splay_tree cases
, location_t switch_location
,
1334 tree type
, tree cond
, bool bool_cond_p
,
1335 bool outside_range_p
)
1337 splay_tree_node default_node
;
1338 splay_tree_node node
;
1341 if (!warn_switch
&& !warn_switch_enum
&& !warn_switch_default
1342 && !warn_switch_bool
)
1345 default_node
= splay_tree_lookup (cases
, (splay_tree_key
) NULL
);
1347 warning_at (switch_location
, OPT_Wswitch_default
,
1348 "switch missing default case");
1350 /* There are certain cases where -Wswitch-bool warnings aren't
1357 so be careful here. */
1358 if (warn_switch_bool
&& bool_cond_p
)
1360 splay_tree_node min_node
;
1361 /* If there's a default node, it's also the value with the minimal
1362 key. So look at the penultimate key (if any). */
1364 min_node
= splay_tree_successor (cases
, (splay_tree_key
) NULL
);
1366 min_node
= splay_tree_min (cases
);
1367 tree min
= min_node
? (tree
) min_node
->key
: NULL_TREE
;
1369 splay_tree_node max_node
= splay_tree_max (cases
);
1370 /* This might be a case range, so look at the value with the
1371 maximal key and then check CASE_HIGH. */
1372 tree max
= max_node
? (tree
) max_node
->value
: NULL_TREE
;
1374 max
= CASE_HIGH (max
) ? CASE_HIGH (max
) : CASE_LOW (max
);
1376 /* If there's a case value > 1 or < 0, that is outside bool
1379 || (max
&& wi::gts_p (wi::to_wide (max
), 1))
1380 || (min
&& wi::lts_p (wi::to_wide (min
), 0))
1388 case, where we want to warn. */
1390 && max
&& wi::to_wide (max
) == 1
1391 && min
&& wi::to_wide (min
) == 0))
1392 warning_at (switch_location
, OPT_Wswitch_bool
,
1393 "switch condition has boolean value");
1396 /* From here on, we only care about enumerated types. */
1397 if (!type
|| TREE_CODE (type
) != ENUMERAL_TYPE
)
1400 /* From here on, we only care about -Wswitch and -Wswitch-enum. */
1401 if (!warn_switch_enum
&& !warn_switch
)
1404 /* Check the cases. Warn about case values which are not members of
1405 the enumerated type. For -Wswitch-enum, or for -Wswitch when
1406 there is no default case, check that exactly all enumeration
1407 literals are covered by the cases. */
1409 /* Clearing COND if it is not an integer constant simplifies
1410 the tests inside the loop below. */
1411 if (TREE_CODE (cond
) != INTEGER_CST
)
1414 /* The time complexity here is O(N*lg(N)) worst case, but for the
1415 common case of monotonically increasing enumerators, it is
1416 O(N), since the nature of the splay tree will keep the next
1417 element adjacent to the root at all times. */
1419 for (chain
= TYPE_VALUES (type
); chain
; chain
= TREE_CHAIN (chain
))
1421 tree value
= TREE_VALUE (chain
);
1422 if (TREE_CODE (value
) == CONST_DECL
)
1423 value
= DECL_INITIAL (value
);
1424 node
= splay_tree_lookup (cases
, (splay_tree_key
) value
);
1427 /* Mark the CASE_LOW part of the case entry as seen. */
1428 tree label
= (tree
) node
->value
;
1429 CASE_LOW_SEEN (label
) = 1;
1433 /* Even though there wasn't an exact match, there might be a
1434 case range which includes the enumerator's value. */
1435 node
= splay_tree_predecessor (cases
, (splay_tree_key
) value
);
1436 if (node
&& CASE_HIGH ((tree
) node
->value
))
1438 tree label
= (tree
) node
->value
;
1439 int cmp
= tree_int_cst_compare (CASE_HIGH (label
), value
);
1442 /* If we match the upper bound exactly, mark the CASE_HIGH
1443 part of the case entry as seen. */
1445 CASE_HIGH_SEEN (label
) = 1;
1450 /* We've now determined that this enumerated literal isn't
1451 handled by the case labels of the switch statement. */
1453 /* If the switch expression is a constant, we only really care
1454 about whether that constant is handled by the switch. */
1455 if (cond
&& tree_int_cst_compare (cond
, value
))
1458 /* If there is a default_node, the only relevant option is
1459 Wswitch-enum. Otherwise, if both are enabled then we prefer
1460 to warn using -Wswitch because -Wswitch is enabled by -Wall
1461 while -Wswitch-enum is explicit. */
1462 warning_at (switch_location
,
1463 (default_node
|| !warn_switch
1466 "enumeration value %qE not handled in switch",
1467 TREE_PURPOSE (chain
));
1470 /* Warn if there are case expressions that don't correspond to
1471 enumerators. This can occur since C and C++ don't enforce
1472 type-checking of assignments to enumeration variables.
1474 The time complexity here is now always O(N) worst case, since
1475 we should have marked both the lower bound and upper bound of
1476 every disjoint case label, with CASE_LOW_SEEN and CASE_HIGH_SEEN
1477 above. This scan also resets those fields. */
1479 splay_tree_foreach (cases
, match_case_to_enum
, type
);
1482 /* Warn for A ?: C expressions (with B omitted) where A is a boolean
1483 expression, because B will always be true. */
1486 warn_for_omitted_condop (location_t location
, tree cond
)
1488 /* In C++ template declarations it can happen that the type is dependent
1489 and not yet known, thus TREE_TYPE (cond) == NULL_TREE. */
1490 if (truth_value_p (TREE_CODE (cond
))
1491 || (TREE_TYPE (cond
) != NULL_TREE
1492 && TREE_CODE (TREE_TYPE (cond
)) == BOOLEAN_TYPE
))
1493 warning_at (location
, OPT_Wparentheses
,
1494 "the omitted middle operand in ?: will always be %<true%>, "
1495 "suggest explicit middle operand");
1498 /* Give an error for storing into ARG, which is 'const'. USE indicates
1499 how ARG was being used. */
1502 readonly_error (location_t loc
, tree arg
, enum lvalue_use use
)
1504 gcc_assert (use
== lv_assign
|| use
== lv_increment
|| use
== lv_decrement
1506 /* Using this macro rather than (for example) arrays of messages
1507 ensures that all the format strings are checked at compile
1509 #define READONLY_MSG(A, I, D, AS) (use == lv_assign ? (A) \
1510 : (use == lv_increment ? (I) \
1511 : (use == lv_decrement ? (D) : (AS))))
1512 if (TREE_CODE (arg
) == COMPONENT_REF
)
1514 if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg
, 0))))
1515 error_at (loc
, READONLY_MSG (G_("assignment of member "
1516 "%qD in read-only object"),
1517 G_("increment of member "
1518 "%qD in read-only object"),
1519 G_("decrement of member "
1520 "%qD in read-only object"),
1521 G_("member %qD in read-only object "
1522 "used as %<asm%> output")),
1523 TREE_OPERAND (arg
, 1));
1525 error_at (loc
, READONLY_MSG (G_("assignment of read-only member %qD"),
1526 G_("increment of read-only member %qD"),
1527 G_("decrement of read-only member %qD"),
1528 G_("read-only member %qD used as %<asm%> output")),
1529 TREE_OPERAND (arg
, 1));
1531 else if (VAR_P (arg
))
1532 error_at (loc
, READONLY_MSG (G_("assignment of read-only variable %qD"),
1533 G_("increment of read-only variable %qD"),
1534 G_("decrement of read-only variable %qD"),
1535 G_("read-only variable %qD used as %<asm%> output")),
1537 else if (TREE_CODE (arg
) == PARM_DECL
)
1538 error_at (loc
, READONLY_MSG (G_("assignment of read-only parameter %qD"),
1539 G_("increment of read-only parameter %qD"),
1540 G_("decrement of read-only parameter %qD"),
1541 G_("read-only parameter %qD use as %<asm%> output")),
1543 else if (TREE_CODE (arg
) == RESULT_DECL
)
1545 gcc_assert (c_dialect_cxx ());
1546 error_at (loc
, READONLY_MSG (G_("assignment of "
1547 "read-only named return value %qD"),
1549 "read-only named return value %qD"),
1551 "read-only named return value %qD"),
1552 G_("read-only named return value %qD "
1553 "used as %<asm%>output")),
1556 else if (TREE_CODE (arg
) == FUNCTION_DECL
)
1557 error_at (loc
, READONLY_MSG (G_("assignment of function %qD"),
1558 G_("increment of function %qD"),
1559 G_("decrement of function %qD"),
1560 G_("function %qD used as %<asm%> output")),
1563 error_at (loc
, READONLY_MSG (G_("assignment of read-only location %qE"),
1564 G_("increment of read-only location %qE"),
1565 G_("decrement of read-only location %qE"),
1566 G_("read-only location %qE used as %<asm%> output")),
1570 /* Print an error message for an invalid lvalue. USE says
1571 how the lvalue is being used and so selects the error message. LOC
1572 is the location for the error. */
1575 lvalue_error (location_t loc
, enum lvalue_use use
)
1580 error_at (loc
, "lvalue required as left operand of assignment");
1583 error_at (loc
, "lvalue required as increment operand");
1586 error_at (loc
, "lvalue required as decrement operand");
1589 error_at (loc
, "lvalue required as unary %<&%> operand");
1592 error_at (loc
, "lvalue required in asm statement");
1599 /* Print an error message for an invalid indirection of type TYPE.
1600 ERRSTRING is the name of the operator for the indirection. */
1603 invalid_indirection_error (location_t loc
, tree type
, ref_operator errstring
)
1608 gcc_assert (c_dialect_cxx ());
1609 error_at (loc
, "invalid type argument (have %qT)", type
);
1611 case RO_ARRAY_INDEXING
:
1613 "invalid type argument of array indexing (have %qT)",
1618 "invalid type argument of unary %<*%> (have %qT)",
1623 "invalid type argument of %<->%> (have %qT)",
1628 "invalid type argument of %<->*%> (have %qT)",
1631 case RO_IMPLICIT_CONVERSION
:
1633 "invalid type argument of implicit conversion (have %qT)",
1641 /* Subscripting with type char is likely to lose on a machine where
1642 chars are signed. So warn on any machine, but optionally. Don't
1643 warn for unsigned char since that type is safe. Don't warn for
1644 signed char because anyone who uses that must have done so
1645 deliberately. Furthermore, we reduce the false positive load by
1646 warning only for non-constant value of type char. */
1649 warn_array_subscript_with_type_char (location_t loc
, tree index
)
1651 if (TYPE_MAIN_VARIANT (TREE_TYPE (index
)) == char_type_node
1652 && TREE_CODE (index
) != INTEGER_CST
)
1653 warning_at (loc
, OPT_Wchar_subscripts
,
1654 "array subscript has type %<char%>");
1657 /* Implement -Wparentheses for the unexpected C precedence rules, to
1658 cover cases like x + y << z which readers are likely to
1659 misinterpret. We have seen an expression in which CODE is a binary
1660 operator used to combine expressions ARG_LEFT and ARG_RIGHT, which
1661 before folding had CODE_LEFT and CODE_RIGHT. CODE_LEFT and
1662 CODE_RIGHT may be ERROR_MARK, which means that that side of the
1663 expression was not formed using a binary or unary operator, or it
1664 was enclosed in parentheses. */
1667 warn_about_parentheses (location_t loc
, enum tree_code code
,
1668 enum tree_code code_left
, tree arg_left
,
1669 enum tree_code code_right
, tree arg_right
)
1671 if (!warn_parentheses
)
1674 /* This macro tests that the expression ARG with original tree code
1675 CODE appears to be a boolean expression. or the result of folding a
1676 boolean expression. */
1677 #define APPEARS_TO_BE_BOOLEAN_EXPR_P(CODE, ARG) \
1678 (truth_value_p (TREE_CODE (ARG)) \
1679 || TREE_CODE (TREE_TYPE (ARG)) == BOOLEAN_TYPE \
1680 /* Folding may create 0 or 1 integers from other expressions. */ \
1681 || ((CODE) != INTEGER_CST \
1682 && (integer_onep (ARG) || integer_zerop (ARG))))
1687 if (code_left
== PLUS_EXPR
)
1688 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1689 "suggest parentheses around %<+%> inside %<<<%>");
1690 else if (code_right
== PLUS_EXPR
)
1691 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1692 "suggest parentheses around %<+%> inside %<<<%>");
1693 else if (code_left
== MINUS_EXPR
)
1694 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1695 "suggest parentheses around %<-%> inside %<<<%>");
1696 else if (code_right
== MINUS_EXPR
)
1697 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1698 "suggest parentheses around %<-%> inside %<<<%>");
1702 if (code_left
== PLUS_EXPR
)
1703 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1704 "suggest parentheses around %<+%> inside %<>>%>");
1705 else if (code_right
== PLUS_EXPR
)
1706 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1707 "suggest parentheses around %<+%> inside %<>>%>");
1708 else if (code_left
== MINUS_EXPR
)
1709 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1710 "suggest parentheses around %<-%> inside %<>>%>");
1711 else if (code_right
== MINUS_EXPR
)
1712 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1713 "suggest parentheses around %<-%> inside %<>>%>");
1716 case TRUTH_ORIF_EXPR
:
1717 if (code_left
== TRUTH_ANDIF_EXPR
)
1718 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1719 "suggest parentheses around %<&&%> within %<||%>");
1720 else if (code_right
== TRUTH_ANDIF_EXPR
)
1721 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1722 "suggest parentheses around %<&&%> within %<||%>");
1726 if (code_left
== BIT_AND_EXPR
|| code_left
== BIT_XOR_EXPR
1727 || code_left
== PLUS_EXPR
|| code_left
== MINUS_EXPR
)
1728 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1729 "suggest parentheses around arithmetic in operand of %<|%>");
1730 else if (code_right
== BIT_AND_EXPR
|| code_right
== BIT_XOR_EXPR
1731 || code_right
== PLUS_EXPR
|| code_right
== MINUS_EXPR
)
1732 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1733 "suggest parentheses around arithmetic in operand of %<|%>");
1734 /* Check cases like x|y==z */
1735 else if (TREE_CODE_CLASS (code_left
) == tcc_comparison
)
1736 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1737 "suggest parentheses around comparison in operand of %<|%>");
1738 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
)
1739 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1740 "suggest parentheses around comparison in operand of %<|%>");
1741 /* Check cases like !x | y */
1742 else if (code_left
== TRUTH_NOT_EXPR
1743 && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right
, arg_right
))
1744 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1745 "suggest parentheses around operand of "
1746 "%<!%> or change %<|%> to %<||%> or %<!%> to %<~%>");
1750 if (code_left
== BIT_AND_EXPR
1751 || code_left
== PLUS_EXPR
|| code_left
== MINUS_EXPR
)
1752 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1753 "suggest parentheses around arithmetic in operand of %<^%>");
1754 else if (code_right
== BIT_AND_EXPR
1755 || code_right
== PLUS_EXPR
|| code_right
== MINUS_EXPR
)
1756 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1757 "suggest parentheses around arithmetic in operand of %<^%>");
1758 /* Check cases like x^y==z */
1759 else if (TREE_CODE_CLASS (code_left
) == tcc_comparison
)
1760 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1761 "suggest parentheses around comparison in operand of %<^%>");
1762 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
)
1763 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1764 "suggest parentheses around comparison in operand of %<^%>");
1768 if (code_left
== PLUS_EXPR
)
1769 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1770 "suggest parentheses around %<+%> in operand of %<&%>");
1771 else if (code_right
== PLUS_EXPR
)
1772 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1773 "suggest parentheses around %<+%> in operand of %<&%>");
1774 else if (code_left
== MINUS_EXPR
)
1775 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1776 "suggest parentheses around %<-%> in operand of %<&%>");
1777 else if (code_right
== MINUS_EXPR
)
1778 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1779 "suggest parentheses around %<-%> in operand of %<&%>");
1780 /* Check cases like x&y==z */
1781 else if (TREE_CODE_CLASS (code_left
) == tcc_comparison
)
1782 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1783 "suggest parentheses around comparison in operand of %<&%>");
1784 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
)
1785 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1786 "suggest parentheses around comparison in operand of %<&%>");
1787 /* Check cases like !x & y */
1788 else if (code_left
== TRUTH_NOT_EXPR
1789 && !APPEARS_TO_BE_BOOLEAN_EXPR_P (code_right
, arg_right
))
1790 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1791 "suggest parentheses around operand of "
1792 "%<!%> or change %<&%> to %<&&%> or %<!%> to %<~%>");
1796 if (TREE_CODE_CLASS (code_left
) == tcc_comparison
)
1797 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1798 "suggest parentheses around comparison in operand of %<==%>");
1799 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
)
1800 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1801 "suggest parentheses around comparison in operand of %<==%>");
1804 if (TREE_CODE_CLASS (code_left
) == tcc_comparison
)
1805 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1806 "suggest parentheses around comparison in operand of %<!=%>");
1807 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
)
1808 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1809 "suggest parentheses around comparison in operand of %<!=%>");
1813 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
1815 if (TREE_CODE_CLASS (code_left
) == tcc_comparison
1816 && code_left
!= NE_EXPR
&& code_left
!= EQ_EXPR
1817 && INTEGRAL_TYPE_P (TREE_TYPE (arg_left
)))
1818 warning_at (EXPR_LOC_OR_LOC (arg_left
, loc
), OPT_Wparentheses
,
1819 "comparisons like %<X<=Y<=Z%> do not "
1820 "have their mathematical meaning");
1821 else if (TREE_CODE_CLASS (code_right
) == tcc_comparison
1822 && code_right
!= NE_EXPR
&& code_right
!= EQ_EXPR
1823 && INTEGRAL_TYPE_P (TREE_TYPE (arg_right
)))
1824 warning_at (EXPR_LOC_OR_LOC (arg_right
, loc
), OPT_Wparentheses
,
1825 "comparisons like %<X<=Y<=Z%> do not "
1826 "have their mathematical meaning");
1830 #undef NOT_A_BOOLEAN_EXPR_P
1833 /* If LABEL (a LABEL_DECL) has not been used, issue a warning. */
1836 warn_for_unused_label (tree label
)
1838 if (!TREE_USED (label
))
1840 if (DECL_INITIAL (label
))
1841 warning (OPT_Wunused_label
, "label %q+D defined but not used", label
);
1843 warning (OPT_Wunused_label
, "label %q+D declared but not defined", label
);
1845 else if (asan_sanitize_use_after_scope ())
1847 if (asan_used_labels
== NULL
)
1848 asan_used_labels
= new hash_set
<tree
> (16);
1850 asan_used_labels
->add (label
);
1854 /* Warn for division by zero according to the value of DIVISOR. LOC
1855 is the location of the division operator. */
1858 warn_for_div_by_zero (location_t loc
, tree divisor
)
1860 /* If DIVISOR is zero, and has integral or fixed-point type, issue a warning
1861 about division by zero. Do not issue a warning if DIVISOR has a
1862 floating-point type, since we consider 0.0/0.0 a valid way of
1863 generating a NaN. */
1864 if (c_inhibit_evaluation_warnings
== 0
1865 && (integer_zerop (divisor
) || fixed_zerop (divisor
)))
1866 warning_at (loc
, OPT_Wdiv_by_zero
, "division by zero");
1869 /* Warn for patterns where memset appears to be used incorrectly. The
1870 warning location should be LOC. ARG0, and ARG2 are the first and
1871 last arguments to the call, while LITERAL_ZERO_MASK has a 1 bit for
1872 each argument that was a literal zero. */
1875 warn_for_memset (location_t loc
, tree arg0
, tree arg2
,
1876 int literal_zero_mask
)
1878 arg0
= fold_for_warn (arg0
);
1879 arg2
= fold_for_warn (arg2
);
1881 if (warn_memset_transposed_args
1882 && integer_zerop (arg2
)
1883 && (literal_zero_mask
& (1 << 2)) != 0
1884 && (literal_zero_mask
& (1 << 1)) == 0)
1885 warning_at (loc
, OPT_Wmemset_transposed_args
,
1886 "%<memset%> used with constant zero length "
1887 "parameter; this could be due to transposed "
1890 if (warn_memset_elt_size
&& TREE_CODE (arg2
) == INTEGER_CST
)
1893 if (TREE_CODE (arg0
) == ADDR_EXPR
)
1894 arg0
= TREE_OPERAND (arg0
, 0);
1895 tree type
= TREE_TYPE (arg0
);
1896 if (type
!= NULL_TREE
&& TREE_CODE (type
) == ARRAY_TYPE
)
1898 tree elt_type
= TREE_TYPE (type
);
1899 tree domain
= TYPE_DOMAIN (type
);
1900 if (!integer_onep (TYPE_SIZE_UNIT (elt_type
))
1901 && domain
!= NULL_TREE
1902 && TYPE_MAX_VALUE (domain
)
1903 && TYPE_MIN_VALUE (domain
)
1904 && integer_zerop (TYPE_MIN_VALUE (domain
))
1905 && integer_onep (fold_build2 (MINUS_EXPR
, domain
,
1907 TYPE_MAX_VALUE (domain
))))
1908 warning_at (loc
, OPT_Wmemset_elt_size
,
1909 "%<memset%> used with length equal to "
1910 "number of elements without multiplication "
1916 /* Subroutine of build_binary_op. Give warnings for comparisons
1917 between signed and unsigned quantities that may fail. Do the
1918 checking based on the original operand trees ORIG_OP0 and ORIG_OP1,
1919 so that casts will be considered, but default promotions won't
1922 LOCATION is the location of the comparison operator.
1924 The arguments of this function map directly to local variables
1925 of build_binary_op. */
1928 warn_for_sign_compare (location_t location
,
1929 tree orig_op0
, tree orig_op1
,
1931 tree result_type
, enum tree_code resultcode
)
1933 if (error_operand_p (orig_op0
) || error_operand_p (orig_op1
))
1936 int op0_signed
= !TYPE_UNSIGNED (TREE_TYPE (orig_op0
));
1937 int op1_signed
= !TYPE_UNSIGNED (TREE_TYPE (orig_op1
));
1938 int unsignedp0
, unsignedp1
;
1940 /* In C++, check for comparison of different enum types. */
1942 && TREE_CODE (TREE_TYPE (orig_op0
)) == ENUMERAL_TYPE
1943 && TREE_CODE (TREE_TYPE (orig_op1
)) == ENUMERAL_TYPE
1944 && TYPE_MAIN_VARIANT (TREE_TYPE (orig_op0
))
1945 != TYPE_MAIN_VARIANT (TREE_TYPE (orig_op1
)))
1947 warning_at (location
,
1948 OPT_Wsign_compare
, "comparison between types %qT and %qT",
1949 TREE_TYPE (orig_op0
), TREE_TYPE (orig_op1
));
1952 /* Do not warn if the comparison is being done in a signed type,
1953 since the signed type will only be chosen if it can represent
1954 all the values of the unsigned type. */
1955 if (!TYPE_UNSIGNED (result_type
))
1957 /* Do not warn if both operands are unsigned. */
1958 else if (op0_signed
== op1_signed
)
1962 tree sop
, uop
, base_type
;
1966 sop
= orig_op0
, uop
= orig_op1
;
1968 sop
= orig_op1
, uop
= orig_op0
;
1970 STRIP_TYPE_NOPS (sop
);
1971 STRIP_TYPE_NOPS (uop
);
1972 base_type
= (TREE_CODE (result_type
) == COMPLEX_TYPE
1973 ? TREE_TYPE (result_type
) : result_type
);
1975 /* Do not warn if the signed quantity is an unsuffixed integer
1976 literal (or some static constant expression involving such
1977 literals or a conditional expression involving such literals)
1978 and it is non-negative. */
1979 if (tree_expr_nonnegative_warnv_p (sop
, &ovf
))
1981 /* Do not warn if the comparison is an equality operation, the
1982 unsigned quantity is an integral constant, and it would fit
1983 in the result if the result were signed. */
1984 else if (TREE_CODE (uop
) == INTEGER_CST
1985 && (resultcode
== EQ_EXPR
|| resultcode
== NE_EXPR
)
1986 && int_fits_type_p (uop
, c_common_signed_type (base_type
)))
1988 /* In C, do not warn if the unsigned quantity is an enumeration
1989 constant and its maximum value would fit in the result if the
1990 result were signed. */
1991 else if (!c_dialect_cxx() && TREE_CODE (uop
) == INTEGER_CST
1992 && TREE_CODE (TREE_TYPE (uop
)) == ENUMERAL_TYPE
1993 && int_fits_type_p (TYPE_MAX_VALUE (TREE_TYPE (uop
)),
1994 c_common_signed_type (base_type
)))
1997 warning_at (location
, OPT_Wsign_compare
,
1998 "comparison of integer expressions of different "
1999 "signedness: %qT and %qT", TREE_TYPE (orig_op0
),
2000 TREE_TYPE (orig_op1
));
2003 /* Warn if two unsigned values are being compared in a size larger
2004 than their original size, and one (and only one) is the result of
2005 a `~' operator. This comparison will always fail.
2007 Also warn if one operand is a constant, and the constant does not
2008 have all bits set that are set in the ~ operand when it is
2011 op0
= c_common_get_narrower (op0
, &unsignedp0
);
2012 op1
= c_common_get_narrower (op1
, &unsignedp1
);
2014 if ((TREE_CODE (op0
) == BIT_NOT_EXPR
)
2015 ^ (TREE_CODE (op1
) == BIT_NOT_EXPR
))
2017 if (TREE_CODE (op0
) == BIT_NOT_EXPR
)
2018 op0
= c_common_get_narrower (TREE_OPERAND (op0
, 0), &unsignedp0
);
2019 if (TREE_CODE (op1
) == BIT_NOT_EXPR
)
2020 op1
= c_common_get_narrower (TREE_OPERAND (op1
, 0), &unsignedp1
);
2022 if (tree_fits_shwi_p (op0
) || tree_fits_shwi_p (op1
))
2025 HOST_WIDE_INT constant
, mask
;
2029 if (tree_fits_shwi_p (op0
))
2032 unsignedp
= unsignedp1
;
2033 constant
= tree_to_shwi (op0
);
2038 unsignedp
= unsignedp0
;
2039 constant
= tree_to_shwi (op1
);
2042 bits
= TYPE_PRECISION (TREE_TYPE (primop
));
2043 if (bits
< TYPE_PRECISION (result_type
)
2044 && bits
< HOST_BITS_PER_LONG
&& unsignedp
)
2046 mask
= HOST_WIDE_INT_M1U
<< bits
;
2047 if ((mask
& constant
) != mask
)
2050 warning_at (location
, OPT_Wsign_compare
,
2051 "promoted ~unsigned is always non-zero");
2053 warning_at (location
, OPT_Wsign_compare
,
2054 "comparison of promoted ~unsigned with constant");
2058 else if (unsignedp0
&& unsignedp1
2059 && (TYPE_PRECISION (TREE_TYPE (op0
))
2060 < TYPE_PRECISION (result_type
))
2061 && (TYPE_PRECISION (TREE_TYPE (op1
))
2062 < TYPE_PRECISION (result_type
)))
2063 warning_at (location
, OPT_Wsign_compare
,
2064 "comparison of promoted ~unsigned with unsigned");
2068 /* RESULT_TYPE is the result of converting TYPE1 and TYPE2 to a common
2069 type via c_common_type. If -Wdouble-promotion is in use, and the
2070 conditions for warning have been met, issue a warning. GMSGID is
2071 the warning message. It must have two %T specifiers for the type
2072 that was converted (generally "float") and the type to which it was
2073 converted (generally "double), respectively. LOC is the location
2074 to which the warning should refer. */
2077 do_warn_double_promotion (tree result_type
, tree type1
, tree type2
,
2078 const char *gmsgid
, location_t loc
)
2082 if (!warn_double_promotion
)
2084 /* If the conversion will not occur at run-time, there is no need to
2086 if (c_inhibit_evaluation_warnings
)
2088 /* If an invalid conversion has occured, don't warn. */
2089 if (result_type
== error_mark_node
)
2091 if (TYPE_MAIN_VARIANT (result_type
) != double_type_node
2092 && TYPE_MAIN_VARIANT (result_type
) != complex_double_type_node
)
2094 if (TYPE_MAIN_VARIANT (type1
) == float_type_node
2095 || TYPE_MAIN_VARIANT (type1
) == complex_float_type_node
)
2096 source_type
= type1
;
2097 else if (TYPE_MAIN_VARIANT (type2
) == float_type_node
2098 || TYPE_MAIN_VARIANT (type2
) == complex_float_type_node
)
2099 source_type
= type2
;
2102 warning_at (loc
, OPT_Wdouble_promotion
, gmsgid
, source_type
, result_type
);
2105 /* Possibly warn about unused parameters. */
2108 do_warn_unused_parameter (tree fn
)
2112 for (decl
= DECL_ARGUMENTS (fn
);
2113 decl
; decl
= DECL_CHAIN (decl
))
2114 if (!TREE_USED (decl
) && TREE_CODE (decl
) == PARM_DECL
2115 && DECL_NAME (decl
) && !DECL_ARTIFICIAL (decl
)
2116 && !TREE_NO_WARNING (decl
))
2117 warning_at (DECL_SOURCE_LOCATION (decl
), OPT_Wunused_parameter
,
2118 "unused parameter %qD", decl
);
2121 /* If DECL is a typedef that is declared in the current function,
2122 record it for the purpose of -Wunused-local-typedefs. */
2125 record_locally_defined_typedef (tree decl
)
2127 struct c_language_function
*l
;
2129 if (!warn_unused_local_typedefs
2131 /* if this is not a locally defined typedef then we are not
2133 || !is_typedef_decl (decl
)
2134 || !decl_function_context (decl
))
2137 l
= (struct c_language_function
*) cfun
->language
;
2138 vec_safe_push (l
->local_typedefs
, decl
);
2141 /* If T is a TYPE_DECL declared locally, mark it as used. */
2144 maybe_record_typedef_use (tree t
)
2146 if (!is_typedef_decl (t
))
2149 TREE_USED (t
) = true;
2152 /* Warn if there are some unused locally defined typedefs in the
2153 current function. */
2156 maybe_warn_unused_local_typedefs (void)
2160 /* The number of times we have emitted -Wunused-local-typedefs
2161 warnings. If this is different from errorcount, that means some
2162 unrelated errors have been issued. In which case, we'll avoid
2163 emitting "unused-local-typedefs" warnings. */
2164 static int unused_local_typedefs_warn_count
;
2165 struct c_language_function
*l
;
2170 if ((l
= (struct c_language_function
*) cfun
->language
) == NULL
)
2173 if (warn_unused_local_typedefs
2174 && errorcount
== unused_local_typedefs_warn_count
)
2176 FOR_EACH_VEC_SAFE_ELT (l
->local_typedefs
, i
, decl
)
2177 if (!TREE_USED (decl
))
2178 warning_at (DECL_SOURCE_LOCATION (decl
),
2179 OPT_Wunused_local_typedefs
,
2180 "typedef %qD locally defined but not used", decl
);
2181 unused_local_typedefs_warn_count
= errorcount
;
2184 vec_free (l
->local_typedefs
);
2187 /* If we're creating an if-else-if condition chain, first see if we
2188 already have this COND in the CHAIN. If so, warn and don't add COND
2189 into the vector, otherwise add the COND there. LOC is the location
2193 warn_duplicated_cond_add_or_warn (location_t loc
, tree cond
, vec
<tree
> **chain
)
2195 /* No chain has been created yet. Do nothing. */
2199 if (TREE_SIDE_EFFECTS (cond
))
2201 /* Uh-oh! This condition has a side-effect, thus invalidates
2211 FOR_EACH_VEC_ELT (**chain
, ix
, t
)
2212 if (operand_equal_p (cond
, t
, 0))
2214 if (warning_at (loc
, OPT_Wduplicated_cond
,
2215 "duplicated %<if%> condition"))
2216 inform (EXPR_LOCATION (t
), "previously used here");
2222 && !CONSTANT_CLASS_P (cond
)
2223 /* Don't infinitely grow the chain. */
2224 && (*chain
)->length () < 512)
2225 (*chain
)->safe_push (cond
);
2228 /* Check and possibly warn if two declarations have contradictory
2229 attributes, such as always_inline vs. noinline. */
2232 diagnose_mismatched_attributes (tree olddecl
, tree newdecl
)
2234 bool warned
= false;
2236 tree a1
= lookup_attribute ("optimize", DECL_ATTRIBUTES (olddecl
));
2237 tree a2
= lookup_attribute ("optimize", DECL_ATTRIBUTES (newdecl
));
2238 /* An optimization attribute applied on a declaration after the
2239 definition is likely not what the user wanted. */
2241 && DECL_SAVED_TREE (olddecl
) != NULL_TREE
2242 && (a1
== NULL_TREE
|| !attribute_list_equal (a1
, a2
)))
2243 warned
|= warning (OPT_Wattributes
,
2244 "optimization attribute on %qD follows "
2245 "definition but the attribute doesn%'t match",
2248 /* Diagnose inline __attribute__ ((noinline)) which is silly. */
2249 const char *noinline
= "noinline";
2251 if (DECL_DECLARED_INLINE_P (newdecl
)
2252 && DECL_UNINLINABLE (olddecl
)
2253 && lookup_attribute (noinline
, DECL_ATTRIBUTES (olddecl
)))
2254 warned
|= warning (OPT_Wattributes
, "inline declaration of %qD follows "
2255 "declaration with attribute %qs", newdecl
, noinline
);
2256 else if (DECL_DECLARED_INLINE_P (olddecl
)
2257 && DECL_UNINLINABLE (newdecl
)
2258 && lookup_attribute ("noinline", DECL_ATTRIBUTES (newdecl
)))
2259 warned
|= warning (OPT_Wattributes
, "declaration of %q+D with attribute "
2260 "%qs follows inline declaration", newdecl
, noinline
);
2265 /* Warn if signed left shift overflows. We don't warn
2266 about left-shifting 1 into the sign bit in C++14; cf.
2267 <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3367.html#1457>
2268 LOC is a location of the shift; OP0 and OP1 are the operands.
2269 Return true if an overflow is detected, false otherwise. */
2272 maybe_warn_shift_overflow (location_t loc
, tree op0
, tree op1
)
2274 if (TREE_CODE (op0
) != INTEGER_CST
2275 || TREE_CODE (op1
) != INTEGER_CST
)
2278 tree type0
= TREE_TYPE (op0
);
2279 unsigned int prec0
= TYPE_PRECISION (type0
);
2281 /* Left-hand operand must be signed. */
2282 if (TYPE_UNSIGNED (type0
))
2285 unsigned int min_prec
= (wi::min_precision (wi::to_wide (op0
), SIGNED
)
2286 + TREE_INT_CST_LOW (op1
));
2287 /* Handle the case of left-shifting 1 into the sign bit.
2288 * However, shifting 1 _out_ of the sign bit, as in
2289 * INT_MIN << 1, is considered an overflow.
2291 if (!tree_int_cst_sign_bit(op0
) && min_prec
== prec0
+ 1)
2293 /* Never warn for C++14 onwards. */
2294 if (cxx_dialect
>= cxx14
)
2296 /* Otherwise only if -Wshift-overflow=2. But return
2297 true to signal an overflow for the sake of integer
2298 constant expressions. */
2299 if (warn_shift_overflow
< 2)
2303 bool overflowed
= min_prec
> prec0
;
2304 if (overflowed
&& c_inhibit_evaluation_warnings
== 0)
2305 warning_at (loc
, OPT_Wshift_overflow_
,
2306 "result of %qE requires %u bits to represent, "
2307 "but %qT only has %u bits",
2308 build2_loc (loc
, LSHIFT_EXPR
, type0
, op0
, op1
),
2309 min_prec
, type0
, prec0
);
2314 /* Warn about boolean expression compared with an integer value different
2315 from true/false. Warns also e.g. about "(i1 == i2) == 2".
2316 LOC is the location of the comparison, CODE is its code, OP0 and OP1
2317 are the operands of the comparison. The caller must ensure that
2318 either operand is a boolean expression. */
2321 maybe_warn_bool_compare (location_t loc
, enum tree_code code
, tree op0
,
2324 if (TREE_CODE_CLASS (code
) != tcc_comparison
)
2328 if (f
= fold_for_warn (op0
),
2329 TREE_CODE (f
) == INTEGER_CST
)
2331 else if (f
= fold_for_warn (op1
),
2332 TREE_CODE (f
) == INTEGER_CST
)
2337 if (!integer_zerop (cst
) && !integer_onep (cst
))
2339 int sign
= (TREE_CODE (op0
) == INTEGER_CST
2340 ? tree_int_cst_sgn (cst
) : -tree_int_cst_sgn (cst
));
2342 || ((code
== GT_EXPR
|| code
== GE_EXPR
) && sign
< 0)
2343 || ((code
== LT_EXPR
|| code
== LE_EXPR
) && sign
> 0))
2344 warning_at (loc
, OPT_Wbool_compare
, "comparison of constant %qE "
2345 "with boolean expression is always false", cst
);
2347 warning_at (loc
, OPT_Wbool_compare
, "comparison of constant %qE "
2348 "with boolean expression is always true", cst
);
2350 else if (integer_zerop (cst
) || integer_onep (cst
))
2352 /* If the non-constant operand isn't of a boolean type, we
2353 don't want to warn here. */
2354 tree noncst
= TREE_CODE (op0
) == INTEGER_CST
? op1
: op0
;
2355 /* Handle booleans promoted to integers. */
2356 if (bool_promoted_to_int_p (noncst
))
2358 else if (TREE_CODE (TREE_TYPE (noncst
)) != BOOLEAN_TYPE
2359 && !truth_value_p (TREE_CODE (noncst
)))
2361 /* Do some magic to get the right diagnostics. */
2362 bool flag
= TREE_CODE (op0
) == INTEGER_CST
;
2363 flag
= integer_zerop (cst
) ? flag
: !flag
;
2364 if ((code
== GE_EXPR
&& !flag
) || (code
== LE_EXPR
&& flag
))
2365 warning_at (loc
, OPT_Wbool_compare
, "comparison of constant %qE "
2366 "with boolean expression is always true", cst
);
2367 else if ((code
== LT_EXPR
&& !flag
) || (code
== GT_EXPR
&& flag
))
2368 warning_at (loc
, OPT_Wbool_compare
, "comparison of constant %qE "
2369 "with boolean expression is always false", cst
);
2373 /* Warn if an argument at position param_pos is passed to a
2374 restrict-qualified param, and it aliases with another argument.
2375 Return true if a warning has been issued. */
2378 warn_for_restrict (unsigned param_pos
, tree
*argarray
, unsigned nargs
)
2380 tree arg
= argarray
[param_pos
];
2381 if (TREE_VISITED (arg
) || integer_zerop (arg
))
2384 location_t loc
= EXPR_LOC_OR_LOC (arg
, input_location
);
2385 gcc_rich_location
richloc (loc
);
2388 auto_vec
<int, 16> arg_positions
;
2390 for (i
= 0; i
< nargs
; i
++)
2395 tree current_arg
= argarray
[i
];
2396 if (operand_equal_p (arg
, current_arg
, 0))
2398 TREE_VISITED (current_arg
) = 1;
2399 arg_positions
.safe_push (i
+ 1);
2403 if (arg_positions
.is_empty ())
2407 FOR_EACH_VEC_ELT (arg_positions
, i
, pos
)
2409 arg
= argarray
[pos
- 1];
2410 if (EXPR_HAS_LOCATION (arg
))
2411 richloc
.add_range (EXPR_LOCATION (arg
), false);
2414 return warning_n (&richloc
, OPT_Wrestrict
, arg_positions
.length (),
2415 "passing argument %i to restrict-qualified parameter"
2416 " aliases with argument %Z",
2417 "passing argument %i to restrict-qualified parameter"
2418 " aliases with arguments %Z",
2419 param_pos
+ 1, arg_positions
.address (),
2420 arg_positions
.length ());
2423 /* Callback function to determine whether an expression TP or one of its
2424 subexpressions comes from macro expansion. Used to suppress bogus
2428 expr_from_macro_expansion_r (tree
*tp
, int *, void *)
2430 if (CAN_HAVE_LOCATION_P (*tp
)
2431 && from_macro_expansion_at (EXPR_LOCATION (*tp
)))
2432 return integer_zero_node
;
2437 /* Possibly warn when an if-else has identical branches. */
2440 do_warn_duplicated_branches (tree expr
)
2442 tree thenb
= COND_EXPR_THEN (expr
);
2443 tree elseb
= COND_EXPR_ELSE (expr
);
2445 /* Don't bother if any of the branches is missing. */
2446 if (thenb
== NULL_TREE
|| elseb
== NULL_TREE
)
2449 /* And don't warn for empty statements. */
2450 if (TREE_CODE (thenb
) == NOP_EXPR
2451 && TREE_TYPE (thenb
) == void_type_node
2452 && TREE_OPERAND (thenb
, 0) == size_zero_node
)
2455 /* ... or empty branches. */
2456 if (TREE_CODE (thenb
) == STATEMENT_LIST
2457 && STATEMENT_LIST_HEAD (thenb
) == NULL
)
2460 /* Compute the hash of the then branch. */
2461 inchash::hash
hstate0 (0);
2462 inchash::add_expr (thenb
, hstate0
);
2463 hashval_t h0
= hstate0
.end ();
2465 /* Compute the hash of the else branch. */
2466 inchash::hash
hstate1 (0);
2467 inchash::add_expr (elseb
, hstate1
);
2468 hashval_t h1
= hstate1
.end ();
2470 /* Compare the hashes. */
2472 && operand_equal_p (thenb
, elseb
, OEP_LEXICOGRAPHIC
)
2473 /* Don't warn if any of the branches or their subexpressions comes
2475 && !walk_tree_without_duplicates (&thenb
, expr_from_macro_expansion_r
,
2477 && !walk_tree_without_duplicates (&elseb
, expr_from_macro_expansion_r
,
2479 warning_at (EXPR_LOCATION (expr
), OPT_Wduplicated_branches
,
2480 "this condition has identical branches");
2483 /* Callback for c_genericize to implement -Wduplicated-branches. */
2486 do_warn_duplicated_branches_r (tree
*tp
, int *, void *)
2488 if (TREE_CODE (*tp
) == COND_EXPR
)
2489 do_warn_duplicated_branches (*tp
);
2493 /* Implementation of -Wmultistatement-macros. This warning warns about
2494 cases when a macro expands to multiple statements not wrapped in
2495 do {} while (0) or ({ }) and is used as a body of if/else/for/while
2496 conditionals. For example,
2498 #define DOIT x++; y++
2503 will increment y unconditionally.
2505 BODY_LOC is the location of the first token in the body after labels
2506 have been parsed, NEXT_LOC is the location of the next token after the
2507 body of the conditional has been parsed, and GUARD_LOC is the location
2508 of the conditional. */
2511 warn_for_multistatement_macros (location_t body_loc
, location_t next_loc
,
2512 location_t guard_loc
, enum rid keyword
)
2514 if (!warn_multistatement_macros
)
2517 /* Ain't got time to waste. We only care about macros here. */
2518 if (!from_macro_expansion_at (body_loc
)
2519 || !from_macro_expansion_at (next_loc
))
2522 /* Let's skip macros defined in system headers. */
2523 if (in_system_header_at (body_loc
)
2524 || in_system_header_at (next_loc
))
2527 /* Find the actual tokens in the macro definition. BODY_LOC and
2528 NEXT_LOC have to come from the same spelling location, but they
2529 will resolve to different locations in the context of the macro
2531 location_t body_loc_exp
2532 = linemap_resolve_location (line_table
, body_loc
,
2533 LRK_MACRO_DEFINITION_LOCATION
, NULL
);
2534 location_t next_loc_exp
2535 = linemap_resolve_location (line_table
, next_loc
,
2536 LRK_MACRO_DEFINITION_LOCATION
, NULL
);
2537 location_t guard_loc_exp
2538 = linemap_resolve_location (line_table
, guard_loc
,
2539 LRK_MACRO_DEFINITION_LOCATION
, NULL
);
2541 /* These are some funky cases we don't want to warn about. */
2542 if (body_loc_exp
== guard_loc_exp
2543 || next_loc_exp
== guard_loc_exp
2544 || body_loc_exp
== next_loc_exp
)
2547 /* Find the macro maps for the macro expansions. */
2548 const line_map
*body_map
= linemap_lookup (line_table
, body_loc
);
2549 const line_map
*next_map
= linemap_lookup (line_table
, next_loc
);
2550 const line_map
*guard_map
= linemap_lookup (line_table
, guard_loc
);
2552 /* Now see if the following token (after the body) is coming from the
2553 same macro expansion. If it is, it might be a problem. */
2554 if (body_map
!= next_map
)
2557 /* The conditional itself must not come from the same expansion, because
2558 we don't want to warn about
2559 #define IF if (x) x++; y++
2561 if (guard_map
== body_map
)
2564 /* Handle the case where NEXT and BODY come from the same expansion while
2565 GUARD doesn't, yet we shouldn't warn. E.g.
2567 #define GUARD if (...)
2568 #define GUARD2 GUARD
2570 and in the definition of another macro:
2576 while (linemap_macro_expansion_map_p (guard_map
))
2578 const line_map_macro
*mm
= linemap_check_macro (guard_map
);
2579 guard_loc_exp
= MACRO_MAP_EXPANSION_POINT_LOCATION (mm
);
2580 guard_map
= linemap_lookup (line_table
, guard_loc_exp
);
2581 if (guard_map
== body_map
)
2585 if (warning_at (body_loc
, OPT_Wmultistatement_macros
,
2586 "macro expands to multiple statements"))
2587 inform (guard_loc
, "some parts of macro expansion are not guarded by "
2588 "this %qs clause", guard_tinfo_to_string (keyword
));