Should "system" ABI be "win64" on x86_64 windows?

[brson]

I don't know anything about the windows ABI, but this seems plausible.

[klutzy]

On win64 LLVM treats extern "C" as same as extern "win64", so current status (extern "system" is extern "C") is okay.
(We have explicit notion of "win64" only because the calling convention is also used in uefi.)

[pnkfelix]

From the evidence we have so far, it sounds like the behavior is going to stay the same from the point of view of the programmer, though we may change the underlying implmentation.

P-low, not 1.0.

[vadimcn]

@brson, I don't quite understand the question you are posing here. Win64 has only one calling convention, so "system" == "C" == "win64".

[brson]

Seems like whether we treat 'system' as 'C' or 'win64' is just an internal detail. Closing.