Re: forcing the linker to be a particular one (i.e. gold vs bfd)

[Vladimir Simonov <sv at sw dot ru>]

On 01/12/2011 06:16 PM, Ian Lance Taylor wrote:
> Vladimir Simonov<sv@sw.ru>  writes:
>
> > 3. What for do we need --enable-gold in configure.ac and
> > gcc_cv_gold/ORIGINAL_GOLD_FOR_TARGET,etc. in gcc/configure.ac, gcc/exec-tool.in?
> > For "Single tree build"?
> > Is this mode used widely? As I understand the most of people use separate
> > binutils/gcc build. In separate build default linker is specified
> > via binutils configure options. So we need not explicit gold support
> > in gcc's configure process.
> > Is "Single tree build" mode support important for gold developers?
>
> Single tree build mode is not important for gold developers, at least
> not for me.
>
>
> > 5. Ones we need to pass some options to collect2, what do you think
> > about -Wc,OPTIONS_FOR_COLLECT2 interface into gcc? Like
> > it is for -Wa/-Wl. "c" in -Wc means collect, may be -Wt is better
> > to avoid confusion with "C" as language.
>
> I don't see a need for a special way to pass options to collect2.  -Wl
> will pass options to collect2 just fine.  If there is some need, it
> should not be -Wc, as libtool uses that to pass options to the compiler.
>
>
> I don't personally care too much about this issue.  At Google we just
> install GNU ld in a different directory under the name "ld", and pass a
> -B option to gcc if we want to use it.  That approach doesn't require
> any changes to any tools.  I'm not opposed to installing the linkers
> under different names and coming up with some way to tell the compiler
> which linker to use, I just don't personally care about it all that
> much.
>
> Ian
Thank you for replay.


So, trying to simplify Nick's patch we may:
1. Eliminate --enable-gold related changes in configure.ac,
gcc/configure.ac, gcc/exec-tool.in. I mean the patch, not
original files.

2. Taking into account current binutils installation layout, I see
two ways:
2.1 Add -Wl,--use-ld=LINKER_NAME support in collect2. collect2 will
strip --use-ld=LINKER_NAME from linker options and call appropriate
linker.
2.2 Leave gcc untouched and do the same work in binutils.
If --enable-gold specified in binutils configure options we create
simple wrapper which will strip --use-ld=LINKER_NAME from linker
options and call appropriate linker. Default linker is defined
by configure options. The wrapper is installed as ld.
The wrapper code should be located in gold directory and built
(and installed as ld) if "make" visits gold directory.

Both have pro and contra. 2.2 - decreases binutils install size,
leaves gcc untouched but adds additional "exec" during link process.

I can try to do any.
What do you think which is better?


Regards
Vladimir Simonov