[PATCH] MC: Don't emit min version directives when -fno-integrated-as is on

[Nico Weber]

On Thu, Jan 22, 2015 at 6:05 AM, Rafael Espíndola <
rafael.espindola at gmail.com> wrote:

> On 22 January 2015 at 00:36, Nico Weber <thakis at chromium.org> wrote:
> > I'm trying to use afl-fuzz with asan on OS X. afl-fuzz tells you to set
> CXX to afl-clang++ and rebuild your program. afl-clang++ then calls clang++
> with -no-integrated-as and -B to a path with its own as wrapper that
> inserts some instrumentation assembly before calling real as. This doesn't
> work on OS X because clang++ writes this .macosx_version_min directive that
> as doesn't support. If I apply this patch, everything does work. So this
> seems like a useful thing to me – are there any downsides to this patch?
>
> Yes, it puts us in a direction we really don't want to go.
>
> On OS X /usr/bin/as is really old and not supported. If afl is using
> it instead clang that is a bug in afl.
>

afl is using -no-integrated-as to munge the asm output. It doesn't care
which as gets run.


> The correct way of making this easier would probably be to write a
> program that is command line compatible with /usr/bin/as but uses MC.
>

That sounds great, but until that exists this patch seems to increase
clang's it's-just-works-iness  by at least 8.3% for a very minor code
change. Once llvm-gas (or however it should be called) exists, it's no
longer necessary.
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