[LLVMdev] LLD: Removing Native file format?

Davide Italiano davide at freebsd.org
Thu Apr 9 13:49:36 PDT 2015


On Thu, Apr 9, 2015 at 1:33 PM, Rui Ueyama <ruiu at google.com> wrote:
> On Thu, Apr 9, 2015 at 1:04 PM, Davide Italiano <davide at freebsd.org> wrote:
>>
>> On Thu, Apr 9, 2015 at 12:17 PM, Rui Ueyama <ruiu at google.com> wrote:
>> > I think I bought up this topic before, but I'd like to propose seriously
>> > removing the Native file format from LLD this time.
>> >
>> > IIUC, the Native file format was designed to be the fastest on-memory or
>> > on-disk file format for object files. The problem is that no one is
>> > working
>> > on that. No LLVM tools can produce object files in the Native, thus the
>> > feature of supporting the format is useless in the linker.
>> >
>> > I'm also skeptical about the very idea of defining a new file format
>> > since
>> > existing file formats look to be good enough.
>> >
>> > It's maintenance cost is real. I needed to submit a few patches for the
>> > Native format for global refactoring.
>> >
>> > Here I'm proposing removing the Native file format support from LLD
>> > unless
>> > there's a person who's going to take the ownership of the feature and
>> > push
>> > really hard to adopt the file format everywhere (not only in the
>> > linker).
>> >
>> > Opinions?
>>
>> With my FreeBSD hat on:
>> FreeBSD doesn't talk anything that's not ELF, it's already pretty
>> time-expensive implementing full support for that to even think about
>> a different format.
>> With my LLD hat on:
>> I've been slowed down from time to time because my patches didn't have
>> support for YAML or Native format. I personally would be very happy to
>> not have to worry about yet-another-different-format that at the time
>> of writing is just incomplete enough to be meaningful.
>
>
> Yup, I was slowed down too. I think the situation was mitigated because I
> removed the round-trip tests, which required us to serialize/de-serialize
> intermediate linker results from/to on-disk files, but yeah, it's there like
> tax. I'm not proposing removing YAML though, since it's useful for writing
> tests. I want to stop supporting the Native.

I didn't either, because I see its usefulness. The same isn't true for
Native, alas. Sorry if it wasn't entirely clear from my previous mail.

-- 
Davide

"There are no solved problems; there are only problems that are more
or less solved" -- Henri Poincare



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