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Add more tests for _Countof #133333

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Merged
merged 1 commit into from
May 7, 2025
Merged

Add more tests for _Countof #133333

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52 changes: 51 additions & 1 deletion clang/test/C/C2y/n3369.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,11 @@
#error "Expected to have _Countof support"
#endif

#define NULL ((void *) 0)

int global_array[12];
int global_multi_array[12][34];
int global_num;

void test_parsing_failures() {
(void)_Countof; // expected-error {{expected expression}}
Expand All @@ -36,6 +40,12 @@ void test_semantic_failures() {
expected-note {{forward declaration of 'struct S'}}
struct T { int x; };
(void)_Countof(struct T); // expected-error {{'_Countof' requires an argument of array type; 'struct T' invalid}}
struct U { int x[3]; };
(void)_Countof(struct U); // expected-error {{'_Countof' requires an argument of array type; 'struct U' invalid}}
int a[3];
(void)_Countof(&a); // expected-error {{'_Countof' requires an argument of array type; 'int (*)[3]' invalid}}
int *p;
(void)_Countof(p); // expected-error {{'_Countof' requires an argument of array type; 'int *' invalid}}
}

void test_constant_expression_behavior(int n) {
Expand Down Expand Up @@ -81,6 +91,22 @@ void test_with_function_param(int array[12], int (*array_ptr)[12], int static_ar
(void)_Countof(static_array); // expected-error {{'_Countof' requires an argument of array type; 'int *' invalid}}
}

void test_func_fix_fix(int i, char (*a)[3][5], int (*x)[_Countof(*a)], char (*)[_Generic(x, int (*)[3]: 1)]); // expected-note {{passing argument to parameter}}
void test_func_fix_var(int i, char (*a)[3][i], int (*x)[_Countof(*a)], char (*)[_Generic(x, int (*)[3]: 1)]); // expected-note {{passing argument to parameter}}
void test_func_fix_uns(int i, char (*a)[3][*], int (*x)[_Countof(*a)], char (*)[_Generic(x, int (*)[3]: 1)]); // expected-note {{passing argument to parameter}}

void test_funcs() {
int i3[3];
int i5[5];
char c35[3][5];
test_func_fix_fix(5, &c35, &i3, NULL);
test_func_fix_fix(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
test_func_fix_var(5, &c35, &i3, NULL);
test_func_fix_var(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
test_func_fix_uns(5, &c35, &i3, NULL);
test_func_fix_uns(5, &c35, &i5, NULL); // expected-warning {{incompatible pointer types passing 'int (*)[5]' to parameter of type 'int (*)[3]'}}
}

void test_multidimensional_arrays() {
int array[12][7];
static_assert(_Countof(array) == 12);
Expand All @@ -102,6 +128,11 @@ void test_unspecified_array_length() {
static_assert(_Countof(**x) == 3);
}

void test_completed_array() {
int a[] = {1, 2, global_num};
static_assert(_Countof(a) == 3);
}

// Test that the return type of _Countof is what you'd expect (size_t).
void test_return_type() {
static_assert(_Generic(typeof(_Countof global_array), typeof(sizeof(0)) : 1, default : 0));
Expand All @@ -121,10 +152,14 @@ void test_typedefs() {
static_assert(_Countof(*x) == 12);
}

void test_zero_size_arrays() {
void test_zero_size_arrays(int n) {
int array[0]; // expected-warning {{zero size arrays are an extension}}
static_assert(_Countof(array) == 0);
static_assert(_Countof(int[0]) == 0); // expected-warning {{zero size arrays are an extension}}
int multi_array[0][n]; // FIXME: Should trigger -Wzero-length-array
static_assert(_Countof(multi_array) == 0);
int another_one[0][3]; // expected-warning {{zero size arrays are an extension}}
static_assert(_Countof(another_one) == 0);
}

void test_struct_members() {
Expand All @@ -144,3 +179,18 @@ void test_compound_literals() {
static_assert(_Countof((int[2]){}) == 2);
static_assert(_Countof((int[]){1, 2, 3, 4}) == 4);
}

/* We don't get a diagnostic for test_f1(), because it ends up unused
* as _Countof() results in an integer constant expression, which is not
* evaluated. However, test_f2() ends up being evaluated, since 'a' is
* a VLA.
*/
static int test_f1();
static int test_f2(); // FIXME: Should trigger function 'test_f2' has internal linkage but is not defined

void test_symbols() {
int a[global_num][global_num];

static_assert(_Countof(global_multi_array[test_f1()]) == 34);
(void)_Countof(a[test_f2()]);
}