Cross-Compiled Linux From Scratch - Version 2.0.0-Sparc64-Multilib

Chapter 5. Constructing Cross-Compile Tools

5.15. Cross GCC-4.6.3 - Static

The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.

5.15.1. Installation of Cross GCC Compiler with Static libgcc and no Threads

The following patch contains a number of updates to the 4.6.3 branch by the GCC developers: 

patch -Np1 -i ../gcc-4.6.3-branch_update-2.patch

Make a couple of essential adjustments to the specs file to ensure GCC uses our build environment: 

patch -Np1 -i ../gcc-4.6.3-specs-1.patch

Change the StartFile Spec and Standard Include Dir so that GCC looks in /tools: 

echo -en '#undef STANDARD_INCLUDE_DIR\n#define STANDARD_INCLUDE_DIR "/tools/include/"\n\n' >> gcc/config/linux.h
echo -en '\n#undef STANDARD_STARTFILE_PREFIX_1\n#define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/"\n' >> gcc/config/linux.h
echo -en '\n#undef STANDARD_STARTFILE_PREFIX_2\n#define STANDARD_STARTFILE_PREFIX_2 ""\n' >> gcc/config/linux.h

Now alter gcc's c preprocessor's default include search path to use /tools only: 

cp -v gcc/Makefile.in{,.orig}
sed -e "s@\(^CROSS_SYSTEM_HEADER_DIR =\).*@\1 /tools/include@g" \
    gcc/Makefile.in.orig > gcc/Makefile.in

We will create a dummy limits.h so the build will not use the one provided by the host distro: 

touch /tools/include/limits.h

The GCC documentation recommends building GCC outside of the source directory in a dedicated build directory: 

mkdir -v ../gcc-build
cd ../gcc-build

Prepare GCC for compilation: 

AR=ar LDFLAGS="-Wl,-rpath,/cross-tools/lib" \
  ../gcc-4.6.3/configure --prefix=/cross-tools \
  --build=${CLFS_HOST} --host=${CLFS_HOST} --target=${CLFS_TARGET} \
  --with-sysroot=${CLFS} --with-local-prefix=/tools --disable-nls \
  --disable-shared --with-mpfr=/cross-tools \
  --with-gmp=/cross-tools --with-ppl=/cross-tools --with-cloog=/cross-tools \
  --without-headers --with-newlib --disable-decimal-float \
  --disable-libgomp --disable-libmudflap --disable-libssp \
  --disable-threads --enable-languages=c --enable-cloog-backend=isl

The meaning of the new configure options:

--with-sysroot=${CLFS}

Tells GCC to consider ${CLFS} as the root file system.

--with-local-prefix=/tools

The purpose of this switch is to remove /usr/local/include from gcc's include search path. This is not absolutely essential, however, it helps to minimize the influence of the host system.

--disable-nls

This disables internationalization as i18n is not needed for the cross-compile tools.

--without-headers

Disables GCC from using the target's Libc when cross compiling.

--with-newlib

Tells GCC that the target libc will use 'newlib'.

--disable-decimal-float

Disables support for the C decimal floating point extension.

--disable-libgomp

Disables the creation of runtime libraries used by GOMP.

--disable-libmudflap

Disables the creation of runtime libaries used by libmudflap.

--disable-libssp

Disables the use of Stack Smashing Protection for runtime libraries.

--disable-threads

This will prevent GCC from looking for the multi-thread include files, since they haven't been created for this architecture yet. GCC will be able to find the multi-thread information after the Glibc headers are created.

--enable-languages=c

This option ensures that only the C compiler is built.

Continue with compiling the package: 

make all-gcc all-target-libgcc

The meaning of the new make options:

all-gcc all-target-libgcc

Compiles only the parts of GCC that are needed at this time, rather than the full package.

Install the package: 

make install-gcc install-target-libgcc

Details on this package are located in Section 10.23.2, “Contents of GCC.”