sim: Fix STATUS_ACCESS_VIOLATION on Windows x86_64 #2771
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Pinging @d3zd3z in case this slipped through the cracks... |
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The C `jmp_buf` embedded in this FFI struct needs 16-byte alignment under mingw's setjmp (saves XMM registers with movaps). The C compiler aligns the struct to 16 to satisfy that, but Rust's repr(C) only picked the 8-byte alignment of [u64; 48], so the field could land 8-byte aligned and setjmp faulted with STATUS_ACCESS_VIOLATION. Signed-off-by: José Simões <jose.simoes@eclo.solutions>
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- Removed the cfg_attr conditionals so it windows-msvc too. - Added a compile-time assertion to document the invariant and will fail the build if a future field reorder/addition ever regresses alignment below 16 bytes. Works on all platforms. Signed-off-by: José Simões <jose.simoes@eclo.solutions>
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Signed-off-by: José Simões <jose.simoes@eclo.solutions>
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@d3zd3z anything missing here? |
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The C
jmp_bufembedded in this FFI struct needs 16-byte alignment under mingw's setjmp (saves XMM registers with movaps). The C compiler aligns the struct to 16 to satisfy that, but Rust's repr(C) only picked the 8-byte alignment of [u64; 48], so the field could land 8-byte aligned and setjmp faulted with STATUS_ACCESS_VIOLATION.