[LLVMdev] Implementing stack frames/vaargs

[Richard Pennington]

Hi,

After several months of procrastination I'm at the point where I'd like 
to implement vaargs in all the code generators that do not support it yet.

As a little background, I'm putting together a version of newlib, 
startup code, linker command files, soft-flt (if needed), and 
compiler-rt that I'm building for the llvm targets supported by qemu. I 
build programs and run them in qemu user mode.  So far, X86 and ARM work 
out of the box. powerpc and sparc work as long as I don't do anything 
using vaargs (no printf :-(). Alpha compiles but I haven't implemented 
the low level system calls yet so I can't verify that it works.

My question is this: which backend would be the best to model changes 
for vaargs after? Which is the most up-to-date? Is there documentation 
somewhere that describes how stack frames and vaargs should be done?

-Rich