[PATCH] D34474: [RFC] [AArch64] Add a win64 specific aarch64 calling convention, for va_list handling

[Tim Northover via Phabricator via llvm-commits]

t.p.northover added a comment.

I think MSVC has to have changed the ABI from AAPCS if they've managed to get a "void *" va_list to work; the extra complexity in AAPCS isn't there for the giggles. x86 appears to mirror floating args into integer registers.

If code isn't expected to interoperate, this becomes analogous to the DarwinPCS calling convention (it exists within lib/Target/AArch64 and affects CodeGen but doesn't need to be exposed in IR). If the Wine use-case does involve interoperation (and is supported) then a separate IR-level calling convention is probably unavoidable.


https://reviews.llvm.org/D34474