Re: [PATCH] Re: libtool-2.4.2 is fine but libtool-2.4.6 very slow.

On 09/19/2015 02:09 AM, Pavel Raiskup wrote:
> Hi Hiroyuki Sato,
> 
> On Wednesday 02 of September 2015 16:00:34 Hiroyuki Sato wrote:
>> This configure.ac is extreme slow on libtool-2.4.6.
>> But It run smoothly on libtool-2.4.2.
>> https://github.com/groonga/groonga/blob/master/configure.ac
> 
> thanks for reproducer!
> 
> This _really_ looks like issue mentioned [1], though the thread is
> believed to be resolved (with existing small slowdown between
> libtool-2.4.5 and 2.4.2).  Let me CC Robert whether this patch does not
> actually fix the "1 sec" slowdown of libtoolize.

This looks very much like the same bug that gettext had:
http://git.savannah.gnu.org/cgit/gettext.git/commit/?id=d75090f2
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=764580

Your proposed solution doesn't seem quite right:

>          # Disable these macros.
>          m4_undefine([m4_dnl])
> -        m4_undefine([m4_include])
>          m4_undefine([m4_m4exit])
>          m4_undefine([m4_m4wrap])
>          m4_undefine([m4_maketemp])
> +        # Rather do not use undefine here because people tend to define
> +        # macros of the same name as file included in their bodies - which
> +        # results in infinite recursion.
> +        m4_define([m4_include], [])

I'd recommend that you use the same fix as gettext, and define ALL of
these macros to an empty string, rather than special-casing m4_include
as the only one that does not get undefined.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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