Cross-Compiled Linux From Scratch - Sysroot - Version SVN-0.0.1-20090726-ARM

Chapter 6. Installing Basic System Software

6.11. GCC-4.4.1

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

6.11.1. Environment Settings

This package requires compiler variables to be set for the target in the environment.

export CC="${CLFS_TARGET}-gcc"
export CXX="${CLFS_TARGET}-g++"
export AR="${CLFS_TARGET}-ar"
export AS="${CLFS_TARGET}-as"
export RANLIB="${CLFS_TARGET}-ranlib"
export LD="${CLFS_TARGET}-ld"
export STRIP="${CLFS_TARGET}-strip"

6.11.2. Installation of GCC

The following patch contains a number of updates to the 4.4.1 branch by the GCC developers:

patch -Np1 -i ../gcc-4.4.1-branch_update-1.patch

Apply a sed substitution that will suppress the installation of libiberty.a. The version of libiberty.a provided by Binutils will be used instead:

cp libiberty/Makefile.in{,.orig}
sed 's/install_to_$(INSTALL_DEST) //' libiberty/Makefile.in.orig > \
    libiberty/Makefile.in

GCC provides a gccbug script which detects at compile time whether mktemp is present, and hardcodes the result in a test. If mktemp is not found, the script will fall back to using less random names for temporary files. mktemp will be installed as part of Coreutils later, so the following sed will simulate its presence:

cp gcc/gccbug.in{,.orig}
sed 's/@have_mktemp_command@/yes/' gcc/gccbug.in.orig > gcc/gccbug.in

The fixincludes script attempts to "fix" the system headers installed so far. Since GCC is cross-compiled expecting the system headers to be in /usr/include, the script will be looking at the host system's headers. The following sed prevents fixincludes from running:

cp gcc/Makefile.in{,.orig}
sed 's@\./fixinc\.sh@-c true@' gcc/Makefile.in.orig > gcc/Makefile.in

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:

LDFLAGS="-Wl,-rpath-link,${CLFS}/cross-tools/${CLFS_TARGET}/lib" \
    ../gcc-4.4.1/configure --prefix=/usr --libexecdir=/usr/lib \
    --build=${CLFS_HOST} --host=${CLFS_TARGET} --target=${CLFS_TARGET} \
    --enable-shared --enable-threads=posix --enable-__cxa_atexit \
    --enable-c99 --enable-long-long --enable-clocale=gnu \
    --enable-languages=c,c++ --disable-libstdcxx-pch

The following will prevent GCC from looking in the wrong directories for headers and libraries:

cp Makefile{,.orig}
sed "/^HOST_\(GMP\|PPL\|CLOOG\)\(LIBS\|INC\)/s:-[IL]/\(lib\|include\)::" \
    Makefile.orig > Makefile

Compile the package:

make

Install the package:

make DESTDIR=${CLFS} install

Some packages expect the C preprocessor to be installed in the /lib directory. To support those packages, create this symlink:

ln -sfv ../usr/bin/cpp ${CLFS}/lib

Many packages use the name cc to call the C compiler. To satisfy those packages, create a symlink:

ln -sfv gcc ${CLFS}/usr/bin/cc

6.11.3. Contents of GCC

Installed programs: c++, cc (link to gcc), cpp, g++, gcc, gccbug, and gcov
Installed libraries: libgcc.a, libgcc_eh.a, libgcc_s.so, libgomp.[a,so], libmudflap.[a,so], libmudflapth.[a,so], libssp.[a,so], libstdc++.[a,so], and libsupc++.a

Short Descriptions

cc

The C compiler

cpp

The C preprocessor; it is used by the compiler to expand the #include, #define, and similar statements in the source files

c++

The C++ compiler

g++

The C++ compiler

gcc

The C compiler

gccbug

A shell script used to help create useful bug reports

gcov

A coverage testing tool; it is used to analyze programs to determine where optimizations will have the most effect

libgcc

Contains run-time support for gcc

libmudflap

The libmudflap libraries are used by GCC for instrumenting pointer and array dereferencing operations.

libstdc++

The standard C++ library

libsupc++

Provides supporting routines for the C++ programming language