svn commit: r465416 - in head/devel: aarch64-gcc amd64-gcc mips-gcc mips64-gcc powerpc64-gcc sparc64-gcc

[Kyle Evans]

On Fri, Mar 23, 2018 at 6:53 PM, John Baldwin <jhb at 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.

Thanks,

Kyle Evans

[1] http://package19.nyi.freebsd.org/data/103i386-default-build-as-user/465853/logs/arm-none-eabi-newlib-2.4.0_1.log