1 /* $NetBSD: gcc_typeof.c,v 1.7 2023/08/02 18:51:25 rillig Exp $ */
2 # 3 "gcc_typeof.c"
3
4 /*
5 * Tests for the GCC extension 'typeof'.
6 *
7 * https://gcc.gnu.org/onlinedocs/gcc/Typeof.html
8 */
9
10 /* lint1-extra-flags: -X 351 */
11
12 void take_double(typeof(0.0));
13
14 void take_function_double_returning_double(
15 typeof(0.0)(
16 typeof(0.0)
17 )
18 );
19
20 void
cast(double (* fn)(double))21 cast(double(*fn)(double))
22 {
23 take_double(0.0);
24
25 /* expect+1: warning: passing 'pointer to function(double) returning double' to incompatible 'double', arg #1 [155] */
26 take_double(fn);
27
28 /* expect+1: warning: passing 'double' to incompatible 'pointer to function(double) returning double', arg #1 [155] */
29 take_function_double_returning_double(0.0);
30
31 take_function_double_returning_double(fn);
32
33 /* identity cast */
34 take_function_double_returning_double((double (*)(double))fn);
35 }
36
37 /*
38 * Since cgram 1.58 from 2014-02-18, when support for __typeof__ was added,
39 * and before cgram.y 1.394 from 2022-04-10, lint ran into an assertion
40 * failure when encountering a redundant type qualifier 'const' or 'volatile'
41 * in a declaration using __typeof__. Seen in sys/sys/lwp.h on x86_64, in
42 * the call atomic_load_consume(&l->l_mutex).
43 */
44 int *volatile lock;
45 const volatile __typeof__(lock) *lock_pointer = &lock;
46
47 /*
48 * Before cgram.y 1.427 from 2023-01-21, lint crashed due to a null pointer
49 * dereference if the __typeof__ operator had an invalid operand. Seen in
50 * _fc_atomic_ptr_cmpexch from fontconfig, which uses <stdatomic.h> provided
51 * by GCC, which in turn uses __auto_type and __typeof__, and lint doesn't
52 * know about __auto_type.
53 */
_fc_atomic_ptr_cmpexch(void)54 void _fc_atomic_ptr_cmpexch(void)
55 {
56 /* expect+1: error: 'expr' undefined [99] */
57 __typeof__ (expr) var = 0;
58 }
59