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Date:	Thu, 25 Apr 2002 19:41:16 +1000 (EST)
From:	=?iso-8859-1?q?Danny=20Smith?= <danny_r_smith_2001 AT yahoo DOT co DOT nz>
Subject:	Re: cygwin ld import library issue fix (removing unused "_nm_" symbols)
To:	Ralf Habacker <Ralf DOT Habacker AT freenet DOT de>, Kde-Cygwin <kde-cygwin AT kde DOT org>,
	Binutils <binutils AT sources DOT redhat DOT com>,
	Cygwin-Apps <cygwin-apps AT cygwin DOT com>
In-Reply-To:	<001101c1ec3c$27465c40$651c440a@BRAMSCHE>
MIME-Version:	1.0

 --- Ralf Habacker <Ralf DOT Habacker AT freenet DOT de> wrote: > Hi,
> this patch fixes an cygwin ld issue (GNU ld version 2.11.92 20011001) I've
> encountered while analysing the runtime linking performance for kde.
> 
> Background:
> 
> The ld-auto-import stuff introduces additional symbols (_nm_...) in the
> import
> library which are only needed for data exports.
> Unfortunally this symbols are generated for every export.
> Additional ld rexports imported "_nm_" symbols from other dlls, so one get
> symbols like "_nm___nm__scanf" for example.
> 
> One can say this isn't a real problem and the answer is yes ... for little
> dll's.
> But if you look in the below mentioned import libraries, one can save about
> 30%
> of the import libraries size.
> For the kde 2.2.2 devel libs and base package this would save about 26MB.
> And this seems to be a fact for applying this fix.
> 
> without patch
> -rwxrwxrwx    1 1002     Kein      3190016 Apr 20 19:12 libkdecore.dll.a
> -rwxrwxrwx    1 1002     Kein         7526 Apr 20 19:01 libkdefakes.dll.a
> -rwxrwxrwx    1 1002     Kein      5693370 Apr 20 01:16 libkdeui.dll.a
> 
> 
> with patch
> -rwxrwxrwx    1 1002     Kein      2126660 Apr 25 10:48 libkdecore.dll.a
> -rwxrwxrwx    1 1002     Kein         1448 Apr 25 10:45 libkdefakes.dll.a
> -rwxrwxrwx    1 1002     Kein      3622512 Apr 25 11:06 libkdeui.dll.a
> 
> 
> $ diff pe-dll.c.orig pe-dll.c -ubBp
> --- pe-dll.c.orig       Wed Apr 24 09:48:59 2002
> +++ pe-dll.c    Thu Apr 25 08:33:08 2002
> @@ -248,6 +250,8 @@ static autofilter_entry_type autofilter_
>    /* Do __imp_ explicitly to save time.  */
>    { "__rtti_", 7 },
>    { "__builtin_", 10 },
> +  // RH: prevent generating reimported functions
> +  { "_nm_", 4 },
>    /* Don't export symbols specifying internal DLL layout.  */
>    { "_head_", 6 },
>    { "_fmode", 6 },
> @@ -1789,6 +1793,8 @@ make_one (exp, parent)
>    quick_symbol (abfd, U ("_imp__"), exp->internal_name, "", id5, BSF_GLOBAL,
> 0);
>    /* Symbol to reference ord/name of imported
>       symbol, used to implement auto-import.  */
> +  /* RH: only for auto-imported data */
> +  if (exp->flag_data)
>    quick_symbol (abfd, U("_nm__"), exp->internal_name, "", id6, BSF_GLOBAL,
> 0);
>    if (pe_dll_compat_implib)
>      quick_symbol (abfd, U ("__imp_"), exp->internal_name, "",
> 
> Any comments ?
> 
> Regards
> Ralf Habacker
> 
>  
Yes, this looks very nice, but does it works against current CVS?  I hope you
can say yes.
Danny.

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