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path: root/test/varargs+aarch64.qbe
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2021-09-07expr: Fix varargs again and add more testsMichael Forney
2021-09-04Use architecture-specific va_list typeMichael Forney
Previously, cproc effectively used used typedef struct { /* 32 bytes, 8-byte aligned */ } __builtin_va_list[1]; However, this is not quite correct for x86_64 nor aarch64, though it was close enough for both to work in most cases. In actuality, for x86_64 we want typedef struct { /* 24 bytes, 8-byte aligned */ } __builtin_va_list[1]; and for aarch64 we want typedef struct { /* 32 bytes, 8-byte aligned */ } __builtin_va_list; The difference only appears when the size of va_list matters, or when va_list is passed as a parameter. However, the former is not often the case, and the aarch64 ABI replaces aggregate arguments with pointers to caller-allocated memory, which is quite similar to arrays decaying to pointers in C except that the struct is not copied. Additionally, riscv64 simply uses typedef void *__builtin_va_list; which again has a different size and calling convention. To fix this, make the __builtin_va_list type architecture-specific and use architecture-specific tests for varargs-related functionality.