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Date:      Fri, 30 Mar 2018 11:40:21 -0700
From:      John Baldwin <jhb@freebsd.org>
To:        Kyle Evans <kevans@freebsd.org>
Cc:        ports-committers@freebsd.org, svn-ports-all@freebsd.org, svn-ports-head@freebsd.org
Subject:   Re: svn commit: r465416 - in head/devel: aarch64-gcc amd64-gcc mips-gcc mips64-gcc powerpc64-gcc sparc64-gcc
Message-ID:  <22752830.FZXTHng1bN@ralph.baldwin.cx>
In-Reply-To: <CACNAnaF8r-kLsrhnSsiEC4ae1%2BkmBTEbzm0A5YF=ySa5_cHerQ@mail.gmail.com>
References:  <201803232353.w2NNrqnJ028176@repo.freebsd.org> <CACNAnaF8r-kLsrhnSsiEC4ae1%2BkmBTEbzm0A5YF=ySa5_cHerQ@mail.gmail.com>

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On Friday, March 30, 2018 11:12:28 AM Kyle Evans wrote:
> On Fri, Mar 23, 2018 at 6:53 PM, John Baldwin <jhb@freebsd.org> wrote:
> > Author: jhb (src,doc committer)
> > Date: Fri Mar 23 23:53:52 2018
> > New Revision: 465416
> > URL: https://svnweb.freebsd.org/changeset/ports/465416
> >
> > Log:
> >   Fix --sysroot for cross-toolchain GCC packages
> >
> >   By default, GCC assumes that a cross compiler should not have any valid
> >   initial include or library paths aside from /usr/local/lib/gcc/<mumble>/.
> >   This means that one cannot use --sysroot to point to a system root for
> >   another architecture and have GCC automatically look for headers in
> >   ${sysroot}/usr/include, etc.  Currently we workaround this in FreeBSD's
> >   build system with explicit -isystem, -B, and -L directives.  However,
> >   this is cumbersome compared to clang (where a bare --sysroot DTRT)
> >   especially when using the compiler to build other software (such as test
> >   programs, etc.).
> >
> >   One can override GCC's assumption and force it to assume that it should
> >   honor --sysroot by setting the '--with-sysroot' option to force GCC to
> >   assume a specific system root.  By setting this to '/', this means that
> >   the cross-compiler will attempt to use the host's headers by default
> >   if --sysroot is not specified, but if --sysroot is specified then
> >   it is fully honored including for include paths and library paths.  With
> >   this change I can now cross-compile both C and C++ binaries simply by
> >   using --sysroot without the need for -isystem, -B, or -L directives.  Note
> >   that the base/gcc and devel/riscv64-gcc ports both use --with-sysroot='/'
> >   already.
> >
> >   By default, GCC looks for headers in /usr/local/include (under the
> >   sysroot) before /usr/include.  To disable this and only look for headers
> >   in /usr/include, patch gcc/Makefile.in to not define LOCAL_INCLUDE_DIR.
> >
> >   Once -nostdinc is no longer required, the headers installed along with the
> >   compiler are now used for compiling worlds and test programs.  The "fixed"
> >   headers in include-fixed are generally not helpful and are also derived
> >   from the host's headers which might not match the target --sysroot, so
> >   just delete them entirely.  Even the stub limits.h headers GCC ships when
> >   using an empty build sysroot are not helpful and need to be removed.
> >
> >   On a related note, I also fixed the name of the C++ include directory
> >   option to configure.  By my reading it is 'with-gxx-include-dir' rather
> >   than 'with-gcc-include-dir'.
> >
> >   Reviewed by:  bapt, brooks, kan
> >   Sponsored by: DARPA / AFRL
> >   Differential Revision:        https://reviews.freebsd.org/D14627
> >
> > Modified:
> >   head/devel/aarch64-gcc/pkg-plist
> >   head/devel/amd64-gcc/pkg-plist
> >   head/devel/mips-gcc/pkg-plist
> >   head/devel/mips64-gcc/pkg-plist
> >   head/devel/powerpc64-gcc/Makefile
> >   head/devel/powerpc64-gcc/pkg-plist
> >   head/devel/sparc64-gcc/pkg-plist
> >
> 
> Hey John,
> 
> Documentation is eluding me here- what was --with-sysroot before? For
> other applications, is there a way to force the old behavior while
> invoking gcc?
> 
> This appears to have caused arm-none-eabi-newlib to fail to build [1],
> I guess because it's pulling in a different <limits.h> (our limits.h?)
> without some LONG_LONG_MAX definitions that it needs. I can patch it
> to use LLONG_ instead of LONG_LONG_, but I have mixed feelings about
> compiling it in this new world order rather than the old world order
> that it's been tested in and expects.

So it may be that the arm compilers that aren't actually targeting
FreeBSD for xtoolchain purposes should keep include-fixed.  (I was surprised
they are using powerpc64-gcc as a master port actually).  That would
let you use the old limits.h.  I'm currently testing a different fix for
amd64-gcc, so I already have a patch to powerpc64-gcc, but I will work on
this next.  Basically, we need to revert the pkg-plist changes for the
two arm ports that kan@ fixed earlier and then change powerpc64-gcc/Makefile
to not remove include-fixed for these two ports.  devel/binutils already
has a similar check based on checking PKGNAMEPREFIX to handle the two
arm ports differently here:

.if ${PKGNAMEPREFIX:M*-*-}
BUTARGET?=      ${PKGNAMEPREFIX}${OPSYS:tl}${OSREL}
.else
BUTARGET?=      ${PKGNAMEPREFIX}unknown-${OPSYS:tl}${OSREL}
.endif

We basically need to invert that condition and then put that around the
${RM} of include-fixed in powerpc64-gcc/Makefile.

-- 
John Baldwin



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