Re: [Tinycc-devel] Allow configuration of tcc libraries search path

[Thomas Preud'homme]

Le samedi 9 juillet 2011 20:44:47, grischka a écrit :
> Thomas Preud'homme wrote:
> > First let's focus on multilib as you said.
> 
> Actually I said "multilib" because you said "multilib".  Which
> means that I've no idea really what it means.
Ah? Ok nevermind. Usually I talk about multiarch but that's not important. 
Let's continue on multilib then.
> 
> > The requirement for multilib is suffix all path from search paths
> > (whatever are these search paths: include search path, library search
> > paths, etc…) by the multilib subdirectory,
> 
> Okay, but then I think that tcc doesn't really have to know all
> that either.  It is just a matter that you can configure as many
> paths as you want in one CONFIG_option.
> 
> Which you have now with the colon separated strings.
True. That's why the first patch tried to do it that way. But it's a bit more 
annoying than the current approach since you have to change all the search 
paths by duplicating them (A:B:C would become 
A/<triplet>:A:B/<triplet>:B:C/<triplet>:C) just to say you want for each 
directory to also try first with <triplet> subdirectory.
> 
> There is also the addition of certain prefixes in tcc_split_path,
> which you don't really need, I assume (and as such would conflict
> with the spirit of tinyness ;).
I agree, it's ugly. I wanted to keep the / and /usr/local prefix in the tcc and 
only specify the subdirectories. But I think this logic should still be needed 
somewhere else anyway — most likely in configure — to make things less painful 
with regards of sysroot. The user should only need to specify something like:
/lib/<triplet>:/lib:/usr/local/lib/<triplet>:/usr/local/lib and configure would 
prepend $sysroot if needed.
> 
> So then it is just a matter of integrating the new feature into
> existing code.
> 
> For example instead of
> 
>      tcc_add_library_path(s, CONFIG_TCC_CRT_PREFIX);
>      tcc_add_library_path(s, CONFIG_SYSROOT CONFIG_TCC_LDDIR);
>      tcc_add_library_path(s, CONFIG_SYSROOT "/usr/local"CONFIG_TCC_LDDIR);
> 
> I'd suggest:
> 
>      tcc_add_library_paths(s, CONFIG_TCC_LIBPATH);
> 
> with in tcc.h:
> 
>      #ifndef CONFIG_TCC_LIBPATH
>      # define CONFIG_TCC_LIBPATH \
>         CONFIG_TCC_CRT_PREFIX ":" \
>         CONFIG_SYSROOT CONFIG_TCC_LDDIR ":" \
>         CONFIG_SYSROOT "/usr/local"CONFIG_TCC_LDDIR);
>      #endif
> 
> which brings us further to have all data in one place (and closer
> to Rob Landley's approach from several years ago which is maybe or
> maybe not a coincidence :).
>      http://lists.gnu.org/archive/html/tinycc-devel/2011-07/msg00013.html
Agreed.
> 
> Plus you don't need CONFIG_TCC_EXTRA_LDDIR because you can simply
> override CONFIG_TCC_LIBPATH.
Agreed again.

But I'd still appreciate a --multilib=<triplet> switch in *complement*. This 
way if you want to add multilib but don't change the default paths, you just 
have to add one switch instead of a long --libpath=<colon_separated_path>.

I wrote the code yesterday. Please take a look. Still missing is the handling 
of elf_interp but this must be added anyway without this option.

By the way, is this normal that only X86_64 ld.so uses CONFIG_TCC_LDDIR or 
does the other ld.so also lack the use of this macro?
> 
> --- grischka
Best regards.

Thomas Preud'homme

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