Re: Compile GCC using only tools isolated from host environment

[Benjamin Lovy <ben@tangram.dev>]

HI,

Thank you for your suggestions.  I've tried the CFLAGS with fixed paths,
and am still not successful.

I think I am trying to do what you describe at the end - I want to produce
a GCC that only depends on artifacts found in my /bootstrap tree.  If I
move this whole tree to a new environment, I'd like to still be able to use
this compiler to build arbitrary software.

> you are not
building a GCC which is meant to run in a new OS tree (chroot or
container, or even reboot into a new OS tree), it's likely you shouldn't
use sysroot at all.

On Tue, Mar 15, 2022 at 3:19 AM Xi Ruoyao <xry111@mengyan1223.wang> wrote:

> On Mon, 2022-03-14 at 18:43 -0400, Benjamin Lovy wrote:
>
> /* snip */
>
> > Now, I would like to build a fresh GCC using the previously build GCC,
> > this
> > glib, and the GMP/MPC/MPFR libraries I just built:
> >
> > /build/gcc-11.2.0/configure \
> > CFLAGS="-Wl,-dynamic-linker=/lib/ld-linux-x86-64.so.2 -Wl,-rpath,/lib
> > -I/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include -I/usr/include
> > -I/usr/include/linux -I/lib/gcc/x86_64-pc-linux-gnu/11.2.0/include-
> > fixed
> > -B/bin" \
>
> I think these FLAGS are mistaken.  --sysroot won't expand -I/usr/include
> to search $SYSROOT/usr/include for example.
>
> And, Without "-O2" your GCC will be built without optimization, which
> will make a stupidly slow compiler.
>
> >   --prefix=/bootstrap/gcc \
> > --host=x86_64-pc-linux-gnu \
> > --with-sysroot=/bootstrap \
>
> You need --with-build-sysroot instead of --with-sysroot.  Read
> https://gcc.gnu.org/install/configure.html for their difference.
>
> Please note --sysroot is mostly for cross-compilation.  If you are not
> building a GCC which is meant to run in a new OS tree (chroot or
> container, or even reboot into a new OS tree), it's likely you shouldn't
> use sysroot at all.
> --
> Xi Ruoyao <xry111@mengyan1223.wang>
> School of Aerospace Science and Technology, Xidian University
>