Re: [PATCH] MIPS gas/ld test suite portability fixes

[Eric Christopher <echristo at redhat dot com>]

> > As long as the arch is passed along as 'from-abi' I'm ok with changing
> > it.
> 
> from-abi is always mips3 for NewABI.
> 

Right, I meant as long as they do this:

gas -march=from-abi -mabi=64

just as they would with a gcc that wasn't configured for the right
abi/isa.

> > The problem with allowing people to just put -mabi=64 on a, say,
> > mips-linux-gnu compiler is that they may expect it's giving them, say,
> > mips4 code (I've heard it) and not mips3 code as you'd want to make it.
> 
> Mips4 is the default for the native IRIX ABI64 toolchain, gcc on IRIX
> defaults to mips3 for ABI64, like Linux does. That's probably the
> source of confusion here.
> 

Undoubtedly.

> > Having it error and make people be specific is the best bet I think, or
> > "from-abi" - at least that way they know that they're getting what we
> > choose :)
> 
> They already specified it with -mabi, as mips3 is the minimum required
> for NewABI.

I think we're running into a difference between explicit command line
options and implicit. You think they implicitly implied mips3, I think
it was an error that they weren't explicit about what they wanted. :) 

As an example what if someone requested -32 on a toolchain that
defaulted to 64-bit? or, even better with a mips64-elf toolchain
specified -mips2? It defaults to o64, but yet mips2 isn't valid for the
abi.

I think if we allow -march=from-abi that'll solve the portable makefile
problem as well - as long as people specify the abi they want and let
from-abi say "gimme the abi, pick the minimum architecture required".

-eric