1 /* $NetBSD: gcc_attribute.c,v 1.13 2023/03/28 14:44:34 rillig Exp $ */
2 # 3 "gcc_attribute.c"
3
4 /*
5 * Tests for the various attributes for functions, types, statements that are
6 * provided by GCC.
7 *
8 * https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html
9 */
10
11 /* lint1-extra-flags: -X 351 */
12
13 void __attribute__((noinline))
do_not_inline(void)14 do_not_inline(void)
15 {
16 }
17
18 /* All pointer arguments must be nonnull. */
19 void __attribute__((nonnull))
20 function_nonnull(void *, const void *, int);
21
22 /*
23 * The documentation suggests that the argument list of nonnull be nonempty,
24 * but GCC 9.3.0 accepts an empty list as well, treating all parameters as
25 * nonnull.
26 */
27 void __attribute__((nonnull()))
28 function_nonnull_list(void *, const void *, int);
29
30 /* Arguments 1 and 2 must be nonnull. */
31 void __attribute__((nonnull(1, 2)))
32 function_nonnull_list(void *, const void *, int);
33
34 /*
35 * Unknown attributes are skipped, as lint does not have a list of all known
36 * GCC attributes.
37 */
38 void __attribute__((unknown_attribute))
39 function_with_unknown_attribute(void);
40
41 /*
42 * There is an attribute called 'pcs', but that attribute must not prevent an
43 * ordinary variable from being named the same. Starting with scan.l 1.77
44 * from 2017-01-07, that variable name generated a syntax error. Fixed in
45 * lex.c 1.33 from 2021-05-03.
46 *
47 * Seen in yds.c, function yds_allocate_slots.
48 */
49 int
local_variable_pcs(void)50 local_variable_pcs(void)
51 {
52 int pcs = 3;
53 return pcs;
54 }
55
56 /*
57 * FIXME: The attributes are handled by different grammar rules even though
58 * they occur in the same syntactical position.
59 *
60 * Grammar rule abstract_decl_param_list handles the first attribute.
61 *
62 * Grammar rule direct_abstract_declarator handles all remaining attributes.
63 *
64 * Since abstract_decl_param_list contains type_attribute_opt, this could be
65 * the source of the many shift/reduce conflicts in the grammar.
66 */
67 int
68 func(
69 int(int)
70 __attribute__((__noreturn__))
71 __attribute__((__noreturn__))
72 );
73
74 /*
75 * https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html says that the
76 * attribute-list is a "possibly empty comma-separated sequence of
77 * attributes".
78 *
79 * No matter whether this particular example is interpreted as an empty list
80 * or a list containing a single empty attribute, the result is the same in
81 * both cases.
82 */
83 void one_empty_attribute(void)
84 __attribute__((/* none */));
85
86 /*
87 * https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html further says that
88 * each individual attribute may be "Empty. Empty attributes are ignored".
89 */
90 void two_empty_attributes(void)
91 __attribute__((/* none */, /* still none */));
92
93 /*
94 * Ensure that __attribute__ can be specified everywhere in a declaration.
95 * This is the simplest possible requirement that covers all valid code.
96 * It accepts invalid code as well, but these cases are covered by GCC and
97 * Clang already.
98 *
99 * Since lint only parses the attributes but doesn't really relate them to
100 * identifiers or other entities, ensuring that valid code can be parsed is
101 * enough for now.
102 *
103 * To really associate __attribute__ with the corresponding entity, the
104 * grammar needs to be rewritten, see the example with __noreturn__ above.
105 */
106 __attribute__((deprecated("d1")))
107 const
108 __attribute__((deprecated("d2")))
109 int
110 __attribute__((deprecated("d3")))
111 *
112 // The below line would produce a syntax error.
113 // __attribute__((deprecated("d3")))
114 const
115 __attribute__((deprecated("d4")))
116 identifier
117 __attribute__((deprecated("d5")))
118 (
119 __attribute__((deprecated("d6")))
120 void
121 __attribute__((deprecated("d7")))
122 )
123 __attribute__((deprecated("d8")))
124 ;
125
126 /*
127 * The attribute 'const' provides stronger guarantees than 'pure', and
128 * 'volatile' is not defined. To keep the grammar simple, any T_QUAL is
129 * allowed at this point, but only syntactically.
130 */
131 int const_function(int) __attribute__((const));
132 /* cover 'gcc_attribute_spec: T_QUAL' */
133 /* expect+1: error: syntax error 'volatile' [249] */
134 int volatile_function(int) __attribute__((volatile));
135