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6c3860ef32
Previous iteration of this did not properly account for the interaction of aligned and packed and would even segfault on a null access in such a case. This version properly handles that interaction by aligning the struct itself instead of the first member and not forcing the struct alignment to 1 if it is packed.
77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
// https://github.com/dlang/dmd/issues/21150
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struct S
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{
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char z[16][256];
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} __attribute__((aligned(_Alignof(unsigned int))));
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_Static_assert(_Alignof(struct S) == _Alignof(unsigned int), "S");
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struct T {
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_Static_assert(1, "");
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char x;
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} __attribute__((aligned(_Alignof(struct S))));
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_Static_assert(_Alignof(struct T) == _Alignof(unsigned int), "T");
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struct __attribute__ ((aligned(8))) Q {
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short f[3];
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};
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_Static_assert(sizeof(struct Q) == 8, "Q1");
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_Static_assert(_Alignof(struct Q) == 8, "Q2");
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struct __attribute__ ((aligned(8))) R {
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short f[3];
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char c;
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};
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_Static_assert(sizeof(struct R) == 8, "R1");
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_Static_assert(_Alignof(struct R) == 8, "R2");
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struct C {
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unsigned _Alignas(2) _Alignas(4) char c;
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}
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__attribute__((aligned(8)));
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_Static_assert(_Alignof(struct C)==8, "C");
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struct __attribute__((aligned(4))) D {
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unsigned char c;
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}
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__attribute__((aligned(8)));
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_Static_assert(_Alignof(struct D)==8, "D");
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//
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// Interaction of aligned() and packed
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//
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#include <stddef.h>
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struct Spacked {
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unsigned a;
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unsigned long long b;
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} __attribute__((aligned(4), packed));
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_Static_assert(_Alignof(struct Spacked) == 4, "Spacked");
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_Static_assert(_Alignof(struct Spacked) == 4, "Spacked");
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_Static_assert(offsetof(struct Spacked, a) == 0, "Spacked.a");
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_Static_assert(offsetof(struct Spacked, b) == sizeof(unsigned), "Spacked.b");
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_Static_assert(sizeof(struct Spacked) == sizeof(unsigned) + sizeof(unsigned long long), "sizeof(Spacked)");
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struct __attribute__((aligned(4))) Spacked2 {
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unsigned a;
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unsigned long long b;
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} __attribute__((packed));
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_Static_assert(_Alignof(struct Spacked2) == 4, "Spacked2");
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_Static_assert(offsetof(struct Spacked2, a) == 0, "Spacked2.a");
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_Static_assert(offsetof(struct Spacked2, b) == sizeof(unsigned), "Spacked2.b");
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_Static_assert(sizeof(struct Spacked2) == sizeof(unsigned) + sizeof(unsigned long long), "sizeof(Spacked2)");
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#pragma pack(push)
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#pragma pack(1)
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struct __attribute__((aligned(4))) Spacked3 {
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unsigned a;
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unsigned long long b;
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};
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#pragma pack(pop)
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_Static_assert(_Alignof(struct Spacked3) == 4, "Spacked3");
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_Static_assert(offsetof(struct Spacked3, a) == 0, "Spacked3.a");
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_Static_assert(offsetof(struct Spacked3, b) == sizeof(unsigned), "Spacked3.b");
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_Static_assert(sizeof(struct Spacked3) == sizeof(unsigned) + sizeof(unsigned long long), "sizeof(Spacked3)");
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