Re: [PATCH] RISC-V: Update multilib-generator to handle V

[Palmer Dabbelt <palmer@rivosinc.com>]

On Fri, 14 Apr 2023 00:15:07 PDT (-0700), Kito Cheng wrote:
> Wait, take second round review:
>
>> * All extensions were being prefixed with an underscore, which leads to
>>   some odd combinations like "rv32gc_v", this just adds underscores to
>>   the multi-letter extensions.
>> * The input base ISAs were being canonicalized, which resulted in some
>>   odd multilib default search paths.  I'm not sure if anything breaks
>>   due to this, but it seems safer to just leave them alone.
>
>>* All extensions were being prefixed with an underscore, which leads to
>>  some odd combinations like "rv32gc_v", this just adds underscores to
>>  the multi-letter extensions.
>
> I think that weirdness can be removed arch-canonicalize I think?
>
> And currently all -march will be canonicalized before query multi lib
>
>> @@ -163,14 +168,13 @@ for cmodel in cmodels:
>>      if cmodel == "compact" and arch.startswith("rv32"):
>>        continue
>>
>> -    arch = arch_canonicalize (arch, args.misa_spec)
>>      arches[arch] = 1
>>      abis[abi] = 1
>>      extra = list(filter(None, extra.split(',')))
>>      ext_combs = expand_combination(ext)
>>      alts = sum([[x] + [x + y for y in ext_combs] for x in [arch] + extra], [])
>>      alts = filter(lambda x: len(x) != 0, alts)
>> -    alts = list(map(lambda a : arch_canonicalize(a, args.misa_spec), alts))
>> +    alts = alts + list(map(lambda a : arch_canonicalize(a, args.misa_spec), alts))
>
> So we don't really need to append non-canonical one to the list?

IIUC the multilib processing happens before the canonicialization, so 
we'd need the non-canonicial strings in there too (as those are what 
most users will provide, and what we have now).  I haven't actually 
tested that, though...