usage of the libdep plugin of LD

usage of the libdep plugin of LD

[Marco Frigerio]

Hi,
Is there a way of making sure that the libdep plugin of LD is used?

I have a static .a library with the __.LIBDEP section, but linking it to an executable raises linking errors.

All the errors go away if I specify manually the same '-lXXX' which is written in __.LIBDEP, suggesting that the latter is ignored.

GNU Binutils v 2.38, gcc 11.3.0, on Ubuntu Linux.

I could not find anything in the man pages, and the LD docs (section 4) do not say anything about enabling/loading plugins.

I hope this is the right place for this kind of questions, my apologies otherwise.
Thanks
 - MF

Re: usage of the libdep plugin of LD

[Howard Chu]

Marco Frigerio via Binutils wrote:
> Hi,
> Is there a way of making sure that the libdep plugin of LD is used?

Not by default. You need to make sure ld is invoked with "-plugin .../libdep_plugin.so" yourself.
Easiest way might be a wrapper script.
> 
> I have a static .a library with the __.LIBDEP section, but linking it to an executable raises linking errors.
> 
> All the errors go away if I specify manually the same '-lXXX' which is written in __.LIBDEP, suggesting that the latter is ignored.
> 
> GNU Binutils v 2.38, gcc 11.3.0, on Ubuntu Linux.
> 
> I could not find anything in the man pages, and the LD docs (section 4) do not say anything about enabling/loading plugins.
> 
> I hope this is the right place for this kind of questions, my apologies otherwise.
> Thanks
>  - MF
> 


-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/

Re: usage of the libdep plugin of LD

[Howard Chu]

Howard Chu wrote:
> Marco Frigerio via Binutils wrote:
>> Hi,
>> Is there a way of making sure that the libdep plugin of LD is used?
> 
> Not by default. You need to make sure ld is invoked with "-plugin .../libdep_plugin.so" yourself.
> Easiest way might be a wrapper script.
>>
>> I have a static .a library with the __.LIBDEP section, but linking it to an executable raises linking errors.
>>
>> All the errors go away if I specify manually the same '-lXXX' which is written in __.LIBDEP, suggesting that the latter is ignored.
>>
>> GNU Binutils v 2.38, gcc 11.3.0, on Ubuntu Linux.

On my Ubuntu system the plugin is in /usr/lib/x86_64-linux-gnu/bfd-plugins/libdep.so
>>
>> I could not find anything in the man pages, and the LD docs (section 4) do not say anything about enabling/loading plugins.
>>
>> I hope this is the right place for this kind of questions, my apologies otherwise.
>> Thanks
>>  - MF
>>
> 
> 


-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/

Re: usage of the libdep plugin of LD

[Marco Frigerio]

> Howard Chu wrote:
> 
> > Marco Frigerio via Binutils wrote:
> > 
> > > Hi,
> > > Is there a way of making sure that the libdep plugin of LD is used?
> > 
> > Not by default. You need to make sure ld is invoked with "-plugin .../libdep_plugin.so" yourself.


Thanks, it works now.
I am sorry I was reading an online version of the man page of LD which does not include the -plugin switch (I guess the page is outdated).

(Hopefully a mention to -plugin will also be added to the online docs https://sourceware.org/binutils/docs-2.40/ld/Plugins.html) 

Best,
 -MF

Re: usage of the libdep plugin of LD

[Nick Clifton]

Hi Marco,

> I am sorry I was reading an online version of the man page of LD which does not include the -plugin switch (I guess the page is outdated).

It does - but not in the section about plugins...

> (Hopefully a mention to -plugin will also be added to the online docs https://sourceware.org/binutils/docs-2.40/ld/Plugins.html)

I have updated the documentation source file (ld/ld.texi) so that the
plugin section of the document now mentions the command line option.

This will not affect the online documentation right away however - that
will happen with the next release.

Cheers
   Nick

Re: usage of the libdep plugin of LD

[Ulf Samuelsson]

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Den 2023-02-13 kl. 17:55, skrev Marco Frigerio via Binutils:
> Hi,
> Is there a way of making sure that the libdep plugin of LD is used?

I think you need to supply an option to the LD command --plugin libdep 
or something similar.

|-plugin |name
    Involve a plugin in the linking process. The name parameter is the
    absolute filename of the plugin.
    Usually this parameter is automatically added by the complier, when
    using link time optimization,
    but users can also add their own plugins if they so wish.

    Note that the location of the compiler originated plugins is
    different from the place where the ar, nm and ranlib programs search
    for their plugins.
    In order for those commands to make use of a compiler based plugin
    it must first be copied into the ${libdir}/bfd-plugins directory.
    All gcc based linker plugins are backward compatible, so it is
    sufficient to just copy in the newest one.


Best Regards
Ulf Samuelsson


>
> I have a static .a library with the __.LIBDEP section, but linking it to an executable raises linking errors.
>
> All the errors go away if I specify manually the same '-lXXX' which is written in __.LIBDEP, suggesting that the latter is ignored.
>
> GNU Binutils v 2.38, gcc 11.3.0, on Ubuntu Linux.
>
> I could not find anything in the man pages, and the LD docs (section 4) do not say anything about enabling/loading plugins.
>
> I hope this is the right place for this kind of questions, my apologies otherwise.
> Thanks
>   - MF