Re: Cygwin libtool confused about link library

JonY <[email protected]> Mon, 9 Mar 2020 23:19:47 +0000

Newsgroups	gmane.comp.gnu.libtool.general,gmane.os.cygwin
Message-ID	<[email protected]>

On 3/9/20 9:01 PM, Simon Marchi wrote:
>> Hello libtool folks,
>> Any ideas about this? Something confused the file magic command?
>> dlltool --identify does show libdl.a is associated with cygwin1.dll for
>> example.
> 
> Hi,
> 
> I stumbled on this and dug into libtool, here's what I found.
> 
> As part of the process of identifying the nature these libraries, libtool uses
> this nm + sed snippet [1]:
> 
> 	win32_nmres=`eval $NM -f posix -A \"$func_to_tool_file_result\" |
> 	  $SED -n -e '
> 	    1,100{
> 		/ I /{
> 		    s|.*|import|
> 		    p
> 		    q
> 		}
> 	    }'`
> 	;;
> 
> The sed scripts looks for a line containing the " I " string.
> 
> With binutils < 2.34, the nm output looked like:
> 
>   /usr/lib/libdl.a[d000000.o]: libdl_dll_iname I 0000000000000000
> 
> With binutils 2.34, the corresponding line is:
> 
>   /usr/lib/libdl.a[d000000.o]: libdl_dll_iname D 0
> 
> And therefore the library is mis-identified.
> 
> The commit that introduced this regression is:
> 
>   commit a288c270991de1578ad28ac312120f4167347234
>   Author: Alan Modra <[email protected]>
>   Date:   Fri May 3 21:36:46 2019 +0930
> 
>       PR24511, nm should not mark symbols in .init_array as "t"
> 
> I tried building the latest commit on the binutils-2_34-branch, and the behavior
> has been restored (the line shows " I " again).  The commit that restored the
> behavior is:
> 
>   commit 40bfb9762747f8336b17c70a0173d10200fa62eb
>   Author: Alan Modra <[email protected]>
>   Date:   Thu Feb 27 17:28:47 2020 +1030
> 
>       Re: PR24511, nm should not mark symbols in .init_array as "t"
> 
> So this should all go back to normal when there is a binutils 2.34.1 release and it is
> packaged by Cygwin.  In the mean time, the commit that restored the behavior could maybe
> be backported in the Cygwin package, but I don't know what the habits are in Cygwin for
> this kind of thing.
> 
> Simon
> 
> [1] https://github.com/autotools-mirror/libtool/blob/b9b44533fbf7c7752ffd255c3d09cc360e24183b/build-aux/ltmain.in#L3050-L3059
> 

Thanks for investigating, I'll see about doing a new binutils release.

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