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Date: Sat, 18 May 2013 02:56:23 +0400
From: Alexander Cherepanov <cherepan@...me.ru>
To: john-dev@...ts.openwall.com
Subject: Re: Unused global symbols in core

On 2013-05-13 13:04, Solar Designer wrote:
> On Sat, May 11, 2013 at 07:55:25PM +0400, Alexander Cherepanov wrote:
>> There are unused global symbols in JtR. Here is the analysis for the core:
>
> Thanks!  What tool are you using to find these?

nm + perl -- http://openwall.com/lists/john-dev/2013/05/11/6 .

I've added a license and some comments to my perl file and am attaching 
it this mail with .txt extension for mail archive.

Since then I searched for a tool for this but found nothing. Probably 
it's so easy to do it with perl or grep that nobody cared to create a 
dedicated tool.

In this context the following tool is frequently mentioned:
http://skynet.ie/~caolan/Packages/callcatcher.html
but it seems to do something else (while also useful).

>> 2. Easy to fix:
>> DES_KS_table                    DES_std.o
>
> Won't fix: making DES_KS_table static, but not DES_KS_current (because
> of its use from other source files), may result in them being placed
> into different sections on some platforms, which may have performance
> impact.  Not that performance of this code matters much now that we're
> using bitslice DES in almost all cases, but I also don't feel like
> putting time into it now, and if I were to put more time into it, I'd be
> making more changes.

Ok, I see. Maybe add a comment about it into the source file?

>> 3. Not used but supposed to be used (described in .h)?
>> itoa64                          common.o<- common.c:11
>
> I actually committed the patch for this, only to notice that itoa64[] is
> heavily used from other source files in jumbo.  Reverted until we
> possibly have a #define JOHN_JUMBO or something.

Ah, I see now what Jim meant.

>> 4. Not used but supposed to be used (described in .h)?
>> fmt_default_valid               formats.o<- formats.c:257
>
> Dropped.  There's no valid reason to ever use a fmt_default_valid().
>
>> fmt_default_binary              formats.o<- formats.c:267
>
> Preserved due to use in jumbo.

Ok, I completely forgot about jumbo here.

-- 
Alexander Cherepanov

View attachment "unused-globals.pl.txt" of type "text/plain" (1218 bytes)

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