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From: "unlvsur at live dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug libstdc++/100057] There are no freestanding C++
Date: Mon, 23 Aug 2021 10:19:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100057

--- Comment #32 from cqwrteur <unlvsur at live dot com> ---
(In reply to cqwrteur from comment #31)
> (In reply to Jonathan Wakely from comment #30)
> > (In reply to cqwrteur from comment #29)
> > > I really want a fix to the script. Thank you !!!
> >=20
> > This is too vague to do anything about.
> >=20
> > Be precise.
>=20
> compile gcc things like with --target=3Dx86_64-elf. then use
> --disable-hosted-libstdcxx build those headers without any libc, not even
> newlib since newlib might implement some things which are not appropriate.
>=20
> Better addon x86_64-elf -mno-red-zone multilibs too.

This not only allows C++ to run in baremetal, but also allows libcs themsel=
ves
to be implemented with C++.

Today the cross compiler build process is like this:

binutils-gdb -> gcc without headers but only build libgcc -> libgcc -> libc=
 ->
rebuild gcc -> libgcc -> libstdc++ -> other libs.

In the future, it should be
binutils-gdb -> gcc without headers but only build libgcc + disable-hosted
libstdc++ -> libgcc -> libc -> rebuild gcc -> libgcc -> libstdc++ -> other
libs.

This will solve the boostrapping problems for libcs like mlibc which is wri=
tten
in C++20.=