aee4925507
Based on post-commit review discussion on 2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith. Other uses of forcing HasEmptyPlaceHolder to false seem OK to me - they're all around pointer/reference types where the pointer/reference token will appear at the rightmost side of the left side of the type name, so they make nested types (eg: the "int" in "int *") behave as though there is a non-empty placeholder (because the "*" is essentially the placeholder as far as the "int" is concerned). This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages outside of clang - lldb seems to have some strange/strong dependence on "char [N]" versus "char[N]" when printing strings (not due to that name appearing in DWARF, but probably due to using clang to stringify type names) that'll need to be addressed, plus a few other odds and ends in other subprojects (clang-tools-extra, compiler-rt, etc).
88 lines
2.8 KiB
C
88 lines
2.8 KiB
C
// RUN: %clang_cc1 %s -triple %itanium_abi_triple -fsyntax-only -verify -Wc++-compat
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// Note: Empty C structs are 4 bytes in the Microsoft ABI.
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struct emp_1 { // expected-warning {{empty struct has size 0 in C, size 1 in C++}}
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};
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union emp_2 { // expected-warning {{empty union has size 0 in C, size 1 in C++}}
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};
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struct emp_3 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
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int : 0;
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};
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union emp_4 { // expected-warning {{union has size 0 in C, size 1 in C++}}
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int : 0;
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};
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struct emp_5 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
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int : 0;
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int : 0;
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};
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union emp_6 { // expected-warning {{union has size 0 in C, size 1 in C++}}
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int : 0;
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int : 0;
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};
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struct emp_7 { // expected-warning {{struct has size 0 in C, size 1 in C++}}
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struct emp_1 f1;
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};
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union emp_8 { // expected-warning {{union has size 0 in C, size 1 in C++}}
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struct emp_1 f1;
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};
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struct emp_9 { // expected-warning {{struct has size 0 in C, non-zero size in C++}}
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struct emp_1 f1;
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union emp_2 f2;
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};
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// Checks for pointer subtraction (PR15683)
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struct emp_1 *func_1p(struct emp_1 *x) { return x - 5; }
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int func_1() {
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struct emp_1 v[1];
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return v - v; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
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}
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int func_2(struct emp_1 *x) {
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return 1 + x - x; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
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}
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int func_3(struct emp_1 *x, struct emp_1 *y) {
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return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
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}
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int func_4(struct emp_1 *x, const struct emp_1 *y) {
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return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
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}
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int func_5(volatile struct emp_1 *x, const struct emp_1 *y) {
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return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1' of zero size has undefined behavior}}
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}
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int func_6() {
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union emp_2 v[1];
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return v - v; // expected-warning {{subtraction of pointers to type 'union emp_2' of zero size has undefined behavior}}
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}
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struct A; // expected-note {{forward declaration of 'struct A'}}
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int func_7(struct A *x, struct A *y) {
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return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct A'}}
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}
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int func_8(struct emp_1 (*x)[10], struct emp_1 (*y)[10]) {
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return x - y; // expected-warning {{subtraction of pointers to type 'struct emp_1[10]' of zero size has undefined behavior}}
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}
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int func_9(struct emp_1 (*x)[], struct emp_1 (*y)[]) {
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return x - y; // expected-error {{arithmetic on a pointer to an incomplete type 'struct emp_1[]'}}
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}
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int func_10(int (*x)[0], int (*y)[0]) {
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return x - y; // expected-warning {{subtraction of pointers to type 'int[0]' of zero size has undefined behavior}}
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}
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