[LLVMdev] [PATCH] LangRef: va_arg doesn't work on X86_64; update example (original) (raw)

Tim Northover t.p.northover at gmail.com
Wed Oct 29 11:21:11 PDT 2014

Hi Ramkumar,

On 28 October 2014 18:32, Ramkumar Ramachandra <artagnon at gmail.com> wrote:

Provide a full-fledged example of working variable arguments on X8664, since it's easily the most popular platform.

I don't think this is a good idea. The section is about all the varargs intrinsics and instructions, so the example should use all of them even if it does have to use a target other than x86_64.

Also, a single example of x86's va_arg handling isn't going to be very enlightening for anyone: either you know the ABI and it's just the "obvious" LLVM IR, or you don't and you won't have a clue what's going on. It's a rather complex and initially confusing topic, and would probably deserve its own article if it's going to be documented.

Cheers.

Tim.

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