This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Several puzzles about gcc top level makefile


"Cheng bin" <amker.cheng@gmail.com> writes:

> 1  : At the end of that makefile , There is a section noted as
> "Regenerating top level configury".
>       It is clear what it do, but for what? Where is this piece of
> code used in building procedure?

Those pieces of code are used by developers if and when they change
the original source files Makefile.tpl, configure.ac, etc.


> 2  : At lines around 462, There is a variable named "RECURSE_FLAGS", I
> also puzzled
>       about its usage. It says that "When doing recursive invocations
> of the top-level Makefile,
>       we don't want the outer make to evaluate them, so we pass these
> variables down
>       unchanged. " Does it mean we will recall the top level makefile?
>       if so, Is "RECURSE_FLAGS" have any relations with the first
> question. Maybe both
>       "Regenerating top level configury" and "RECURSE_FLAGS" is used
> to  compile gcc
>       several times in bootstrap.
>       Here I need a confirmation.

If you look at the uses of RECURSE_FLAGS_TO_PASS you will see the
cases where the top-level Makefile is reused in a recursive call to
make.


> 3  : For the cross compiler, I configured and compiled gcc twice, once
> with just language C
>       supported, once with languages C/C++ supported. I compared the
> two top level makefile
>       generated by configure and found the difference is that
> libiberty and libstdc++-v3 is
>       compiled for target at the second time. So here is the question:
> libstdc++v3 is compiled
>       for target as the c++ runtime library, but what libiberty for? I
> can only infer that libstdc++v3
>       needs it(otherwise why the first time which only supports c
> language do not have it
>       compiled?). Unfortunately, I did not find any code in
> libstdc++-v3 which calls functions
>       in libiberty.

libstdc++-v3 uses the C++ demangler from libiberty.

Ian


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]