| 1 | // RUN: %clang_cc1 %s -triple %itanium_abi_triple -fsyntax-only -verify -Wc++-compat |
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| 2 | |
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| 3 | // Note: Empty C structs are 4 bytes in the Microsoft ABI. |
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| 4 | |
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| 5 | struct emp_1 { // expected-warning {{empty struct has size 0 in C, size 1 in C++}} |
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| 6 | }; |
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| 7 | |
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| 8 | union emp_2 { // expected-warning {{empty union has size 0 in C, size 1 in C++}} |
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| 9 | }; |
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| 10 | |
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| 11 | struct emp_3 { // expected-warning {{struct has size 0 in C, size 1 in C++}} |
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| 12 | int : 0; |
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| 13 | }; |
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| 14 | |
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| 15 | union emp_4 { // expected-warning {{union has size 0 in C, size 1 in C++}} |
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| 16 | int : 0; |
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| 17 | }; |
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| 18 | |
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| 19 | struct emp_5 { // expected-warning {{struct has size 0 in C, size 1 in C++}} |
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| 20 | int : 0; |
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| 21 | int : 0; |
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| 22 | }; |
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| 23 | |
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| 24 | union emp_6 { // expected-warning {{union has size 0 in C, size 1 in C++}} |
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| 25 | int : 0; |
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| 26 | int : 0; |
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| 27 | }; |
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| 28 | |
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| 29 | struct emp_7 { // expected-warning {{struct has size 0 in C, size 1 in C++}} |
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| 30 | struct emp_1 f1; |
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| 31 | }; |
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| 32 | |
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| 33 | union emp_8 { // expected-warning {{union has size 0 in C, size 1 in C++}} |
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| 34 | struct emp_1 f1; |
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| 35 | }; |
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| 36 | |
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| 37 | struct emp_9 { // expected-warning {{struct has size 0 in C, non-zero size in C++}} |
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| 38 | struct emp_1 f1; |
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| 39 | union emp_2 f2; |
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| 40 | }; |
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| 41 | |
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| 42 | // Checks for pointer subtraction (PR15683) |
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| 43 | struct emp_1 *func_1p(struct emp_1 *x) { return x - 5; } |
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| 44 | |
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| 45 | int func_1() { |
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| 46 | struct emp_1 v[1]; |
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| 47 | return v - v; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}} |
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| 48 | } |
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| 49 | |
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| 50 | int func_2(struct emp_1 *x) { |
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| 51 | return 1 + x - x; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}} |
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| 52 | } |
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| 53 | |
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| 54 | int func_3(struct emp_1 *x, struct emp_1 *y) { |
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| 55 | return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}} |
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| 56 | } |
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| 57 | |
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| 58 | int func_4(struct emp_1 *x, const struct emp_1 *y) { |
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| 59 | return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}} |
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| 60 | } |
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| 61 | |
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| 62 | int func_5(volatile struct emp_1 *x, const struct emp_1 *y) { |
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| 63 | return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}} |
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| 64 | } |
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| 65 | |
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| 66 | int func_6() { |
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| 67 | union emp_2 v[1]; |
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| 68 | return v - v; // expected-warning {{subtraction of pointers to type 'union emp_2' of zero size has undefined behavior}} |
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| 69 | } |
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| 70 | |
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| 71 | struct A; // expected-note {{forward declaration of 'struct A'}} |
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| 72 | |
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| 73 | int func_7(struct A *x, struct A *y) { |
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| 74 | return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct A'}} |
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| 75 | } |
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| 76 | |
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| 77 | int func_8(struct emp_1 (*x)[10], struct emp_1 (*y)[10]) { |
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| 78 | return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1 [10]' of zero size has undefined behavior}} |
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| 79 | } |
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| 80 | |
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| 81 | int func_9(struct emp_1 (*x)[], struct emp_1 (*y)[]) { |
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| 82 | return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct emp_1 []'}} |
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| 83 | } |
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| 84 | |
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| 85 | int func_10(int (*x)[0], int (*y)[0]) { |
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| 86 | return x - y; // expected-warning {{subtraction of pointers to type 'int [0]' of zero size has undefined behavior}} |
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| 87 | } |
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| 88 | |
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