Re: [RFC] Add "riscv-" for embedded cross toolchains

[Jim Wilson]

On 07/03/2018 03:29 AM, Ben Elliston wrote:
> +riscv-linux                                    riscv-unknown-linux-gnu

Accepting riscv-linux isn't OK.  That will cause complications.  Though 
I'm not sure if that can be easily avoided if we allow riscv-elf.

There are no plans for any tools to accept riscv- as a CPU, so adding 
support for this to config.sub isn't very useful.

Personally, I think Palmer's suggestion of mapping riscv to riscv32 is 
the best compromise.  I realize that Liviu isn't happy about that, but 
we can't do much about that.

Most GNU tools accept --program-transform-name as a configure option, so 
it is easy to strip off the 32 or 64 in the program name at install time 
if you wish.  That should solve Liviu's problem.

I think Liviu's argument has a flaw.  While it is true that both riscv32 
and risvc64 can emit both 32-bit and 64-bit code, they have different 
defaults.  riscv32 emits 32-bit by default, and riscv64 emits 64-bit by 
default.  That is a property we lose if we allow riscv, because it won't 
be obvious if 32-bit or 64-bit code is the default.

Jim