Re: undefined reference to `pcre_jit_exec'

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Oct 12, 2017, 21:05 UTC
Message-ID: <874lr46prx.fsf@evledraar.booking.com>
In-Reply-To: <20171012203832.ui52j7cdrztc6vhs@sigill.intra.peff.net>

On Thu, Oct 12 2017, Jeff King jotted:

Show 18 quoted lines

> On Thu, Oct 12, 2017 at 04:34:38PM -0400, Jeffrey Walton wrote:
>
>> > It looks like autoconf turns on USE_LIBPCRE1, but isn't smart enough to
>> > test NO_LIBPCRE1_JIT.
>>
>> If Git wants Jit, then I am inclined to configure PCRE to provide it.
>
> It does make things faster. OTOH, we lived for many years without it, so
> certainly it's not the end of the world to build without it.
>
> There are some numbers in the commit message of fbaceaac47 (grep: add
> support for the PCRE v1 JIT API, 2017-05-25).
>
>> A quick question if you happen to know... Does PCRE Jit cause a loss
>> of NX-stacks? If it causes a loss of NX-stacks, then I think I prefer
>> to disable it.
>
> I don't know. Ævar (cc'd) might.

Sorry, no idea. I do see some references to that in sljit (which pcre JIT uses), but haven't tried this myself. From what I understand of how NX works it should fail really fast if it doesn't, so it would be cool if you could try it and report if it works.