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分类: 嵌入式
2014-03-20 22:55:22
GCC now requires the GMP, MPFR and MPC packages. As these packages may not be included in your host distribution, they will be built with GCC. Unpack each package into the GCC source directory and rename the resulting directories so the GCC build procedures will automatically use them:
tar -jxf ../mpfr-3.1.0.tar.bz2 mv -v mpfr-3.1.0 mpfr tar -jxf ../gmp-5.0.2.tar.bz2 mv -v gmp-5.0.2 gmp tar -zxf ../mpc-0.9.tar.gz mv -v mpc-0.9 mpc
Apply a patch that will allow the building of the libiberty and zlib target libraries to be disabled as these do not build correctly in a cross-compiled environment:
patch -Np1 -i ../gcc-4.6.1-cross_compile-1.patch
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:
../gcc-4.6.1/configure \ --target=$LFS_TGT --prefix=/tools \ --disable-nls --disable-shared --disable-multilib \ --disable-decimal-float --disable-threads \ --disable-libmudflap --disable-libssp \ --disable-libgomp --disable-libquadmath \ --disable-target-libiberty --disable-target-zlib \ --enable-languages=c --without-ppl --without-cloog \ --with-mpfr-include=$(pwd)/../gcc-4.6.1/mpfr/src \ --with-mpfr-lib=$(pwd)/mpfr/src/.libs
The meaning of the configure options:
--disable-sharedThis switch forces GCC to link its internal libraries statically. We do this to avoid possible issues with the host system.
--disable-decimal-float, --disable-threads, --disable-libmudflap, --disable-libssp, --disable-libgomp, --disable-libquadmath --disable-target-libiberty --disable-target-zlibThese switches disable support for the decimal floating point extension, threading, libmudflap, libssp and libgomp, libquadmath, libiberty and zlib respectively. These features will fail to compile when building a cross-compiler and are not necessary for the task of cross-compiling the temporary libc.
--disable-multilibOn x86_64, LFS does not yet support a multilib configuration. This switch is harmless for x86.
--enable-languages=cThis option ensures that only the C compiler is built. This is the only language needed now.
--without-ppl, --without-cloogThese switches prevent GCC from building against the PPL and CLooG libraries which may be present on the host system, but will not be available in the chroot environment.
Compile GCC by running:
make
Compilation is now complete. At this point, the test suite would normally be run, but, as mentioned before, the test suite framework is not in place yet. The benefits of running the tests at this point are minimal since the programs from this first pass will soon be replaced.
Install the package:
make install
Using --disable-shared means that the libgcc_eh.a file isn't created and installed. The Glibc package depends on this library as it uses-lgcc_eh within its build system. This dependency can be satisfied by creating a symlink tolibgcc.a, since that file will end up containing the objects normally contained inlibgcc_eh.a:
ln -vs libgcc.a `$LFS_TGT-gcc -print-libgcc-file-name | \ sed 's/libgcc/&_eh/'`