576161cb60
Unlike C++, C allows the definition of an uninitialized `const` object. If the object has static or thread storage duration, it is still zero-initialized, otherwise, the object is left uninitialized. In either case, the code is not compatible with C++. This adds a new diagnostic group, `-Wdefault-const-init-unsafe`, which is on by default and diagnoses any definition of a `const` object which remains uninitialized. It also adds another new diagnostic group, `-Wdefault-const-init` (which also enabled the `unsafe` variant) that diagnoses any definition of a `const` object (including ones which are zero-initialized). This diagnostic is off by default. Finally, it adds `-Wdefault-const-init` to `-Wc++-compat`. GCC diagnoses these situations under this flag. Fixes #19297
96 lines
3.6 KiB
C
96 lines
3.6 KiB
C
// RUN: %clang_cc1 -fsyntax-only -verify %s
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void *test1(void) { return 0; }
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void test2 (const struct {int a;} *x) {
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// expected-note@-1 {{variable 'x' declared const here}}
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x->a = 10;
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// expected-error-re@-1 {{cannot assign to variable 'x' with const-qualified type 'const struct (unnamed struct at {{.*}}assign.c:5:19) *'}}
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}
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typedef int arr[10];
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void test3(void) {
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const arr b = {}; // expected-note {{variable 'b' declared const here}}
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const int b2[10] = {}; // expected-note {{variable 'b2' declared const here}}
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b[4] = 1; // expected-error {{cannot assign to variable 'b' with const-qualified type 'const arr' (aka 'const int[10]')}}
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b2[4] = 1; // expected-error {{cannot assign to variable 'b2' with const-qualified type 'const int[10]'}}
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}
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typedef struct I {
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const int a; // expected-note 4{{nested data member 'a' declared const here}} \
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expected-note 6{{data member 'a' declared const here}}
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} I;
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typedef struct J {
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struct I i;
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} J;
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typedef struct K {
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struct J *j;
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} K;
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void testI(struct I i1, struct I i2) {
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i1 = i2; // expected-error {{cannot assign to variable 'i1' with const-qualified data member 'a'}}
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}
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void testJ1(struct J j1, struct J j2) {
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j1 = j2; // expected-error {{cannot assign to variable 'j1' with nested const-qualified data member 'a'}}
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}
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void testJ2(struct J j, struct I i) {
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j.i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
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}
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void testK1(struct K k, struct J j) {
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*(k.j) = j; // expected-error {{cannot assign to lvalue with nested const-qualified data member 'a'}}
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}
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void testK2(struct K k, struct I i) {
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k.j->i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
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}
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void testI_(I i1, I i2) {
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i1 = i2; // expected-error {{cannot assign to variable 'i1' with const-qualified data member 'a'}}
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}
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void testJ1_(J j1, J j2) {
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j1 = j2; // expected-error {{cannot assign to variable 'j1' with nested const-qualified data member 'a'}}
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}
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void testJ2_(J j, I i) {
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j.i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
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}
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void testK1_(K k, J j) {
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*(k.j) = j; // expected-error {{cannot assign to lvalue with nested const-qualified data member 'a'}}
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}
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void testK2_(K k, I i) {
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k.j->i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
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}
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// PR39946: Recursive checking of hasConstFields caused stack overflow.
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struct L { // expected-note {{definition of 'struct L' is not complete until the closing '}'}}
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struct L field; // expected-error {{field has incomplete type 'struct L'}}
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};
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void testL(struct L *l) {
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*l = 0; // expected-error {{assigning to 'struct L' from incompatible type 'int'}}
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}
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// Additionally, this example overflowed the stack when figuring out the field.
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struct M1; // expected-note {{forward declaration of 'struct M1'}}
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struct M2 {
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//expected-note@+1 {{nested data member 'field' declared const here}}
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const struct M1 field; // expected-error {{field has incomplete type 'const struct M1'}}
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};
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struct M1 {
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struct M2 field;
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};
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void testM(struct M1 *l) {
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*l = 0; // expected-error {{cannot assign to lvalue with nested const-qualified data member 'field'}}
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}
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struct N1; // expected-note {{forward declaration of 'struct N1'}}
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struct N2 {
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struct N1 field; // expected-error {{field has incomplete type 'struct N1'}}
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};
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struct N1 {
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struct N2 field;
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};
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void testN(struct N1 *l) {
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*l = 0; // expected-error {{assigning to 'struct N1' from incompatible type 'int'}}
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}
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