[LLVMdev] Semantics of __builtin_setjmp/__builtin_longjmp (original) (raw)

Tim Northover t.p.northover at gmail.com
Tue Feb 10 13:16:32 PST 2015

(b) Are they supposed to be compatible with GCC?

I think they're probably not supposed to be compatible with libc, but should be with GCC.

Libc gets to choose its implementation in setjmp.h. It might implement them completely separately (which would still work however we implement the __builtins), or it might make use of the __builtins (in which case we should certainly make sure they're compatible).

If not with libc, why with GCC?

Because the GCC builtins are an ABI issue controlled by the compiler: we need to be compatible to mix object files on the platform.

Cheers.

Tim.

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