cross-toolchain/altcross.sh

#!/bin/bash
set -e
set -x

TARGET=aarch64-linux-gnu

KERNEL_SOURCE="`find /usr/src/kernel/sources -type f -name 'kernel-source-*.tar'`"
BINUTILS_SOURCE="`find /usr/src/binutils-source -type f -name 'binutils-*.tar'`"
GCC_SOURCE="`find /usr/src/gcc-source -type f -name 'gcc-*.tar'`"
GLIBC_SOURCE="`find /usr/src/glibc-source -type f -name 'glibc-*.tar'`"

getversion() {
	local fname="${1##*/}"
	local bname="${fname%.tar*}"
	local ver="${bname#*-}"
	echo "$ver"
}

GCC_VERSION=`getversion $GCC_SOURCE`
GCC_MAJOR_VERSION="${GCC_VERSION%%.*}"

BUILDDIR="`pwd`/build"
SRCDIR="`pwd`/src"
INSTALLDIR="`pwd`/inst/altcross-gcc-${GCC_VERSION}"
SYSROOT=/$TARGET/libc
SYSROOTDIR="$INSTALLDIR/$SYSROOT"

mkdir -p -m755 "$SRCDIR"
cd "$SRCDIR"

mkdir -p -m755 linux binutils gcc glibc
tar -x --strip-components=1 -f "$KERNEL_SOURCE" -C linux
tar -x --strip-components=1 -f "$BINUTILS_SOURCE" -C binutils
tar -x --strip-components=1 -f "$GCC_SOURCE" -C gcc
tar -x --strip-components=1 -f "$GLIBC_SOURCE" -C glibc

cd "gcc"
sed -i contrib/download_prerequisites -e '/base_url=/s/ftp/http/'
./contrib/download_prerequisites

mkdir -p -m755 "$INSTALLDIR/bin"
export PATH="$INSTALLDIR/bin:/usr/lib/ccache:$PATH"
unset LD_LIBRARY_PATH

mkdir -p -m755 \
	"$BUILDDIR/obj_binutils" \
	"$BUILDDIR/obj_gcc" \
	"$BUILDDIR/obj_glibc" \
	"$BUILDDIR/obj_linux" \

make -j$(nproc) \
	-C "$SRCDIR/linux" \
	O="$BUILDDIR/obj_linux" \
	ARCH=arm64 \
	INSTALL_HDR_PATH="$SYSROOTDIR/usr" \
	headers_install

# binutils

cd "$BUILDDIR/obj_binutils"
../../src/binutils/configure \
	--target="$TARGET" \
	--prefix= \
	--with-sysroot="$SYSROOT" \
	--with-build-sysroot="$SYSROOTDIR" \
	--disable-multilib

make -j$(nproc)
make -j$(nproc) install DESTDIR="$INSTALLDIR"

# gcc 
# Disable libsanitizer to avoid the build failure:
#
# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp: In function ‘void __asan::AsanCheckIncompatibleRT()’:
# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp:217:21: error: ‘PATH_MAX’ was not declared in this scope
#  217 |       char filename[PATH_MAX];
#      |                     ^~~~~~~~
# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp:218:35: error: ‘filename’ was not declared in this scope; did you mean ‘fileno’?
#  218 |       MemoryMappedSegment segment(filename, sizeof(filename));
#      |                                   ^~~~~~~~
#      |                                   fileno

cd "$BUILDDIR/obj_gcc"
../../src/gcc/configure \
	--prefix= \
	--target=$TARGET \
	--enable-languages=c,c++ \
	--enable-version-specific-runtime-libs \
	--with-sysroot="$SYSROOT" \
	--with-build-sysroot="$SYSROOTDIR" \
	--with-gcc-major-version-only \
	--disable-libsanitizer \
	--disable-multilib

# compiler only
make -j$(nproc) all-gcc
make -j$(nproc) install-gcc DESTDIR="$INSTALLDIR"


# glibc

cd "$BUILDDIR/obj_glibc"
../../src/glibc/configure \
	--prefix=/usr \
	--target=$TARGET \
	--host=$TARGET \
	--build="$MACHTYPE" \
	--with-sysroot="$SYSROOT" \
       	--with-build-sysroot="$SYSROOTDIR" \
	--with-headers="$SYSROOTDIR"/usr/include \
	--with-lib="$SYSROOTDIR"/usr/lib \
	--disable-multilib \
	--disable-crypt \
	libc_cv_forced_unwind=yes

# glibc: headers + C runtime bits
make -j$(nproc) install-bootstrap-headers=yes install-headers DESTDIR="$SYSROOTDIR"
make -j$(nproc) csu/subdir_lib
install -d -m755 "$SYSROOTDIR"/usr/lib
install csu/crt1.o csu/crti.o csu/crtn.o "$SYSROOTDIR"/usr/lib
$TARGET-gcc -nostdlib -nostartfiles -shared -x c /dev/null -o "$SYSROOTDIR"/usr/lib/libc.so
touch "$SYSROOTDIR"/usr/include/gnu/stubs.h "$SYSROOTDIR"/usr/include/bits/stdio_lim.h

# GCC: runtime (libgcc)
cd "$BUILDDIR/obj_gcc"
make -j$(nproc) all-target-libgcc
make -j$(nproc) install-target-libgcc DESTDIR="$INSTALLDIR"

# finish off glibc 
cd "$BUILDDIR/obj_glibc"
make -j$(nproc)
make install DESTDIR="$SYSROOTDIR"

# finish off GCC
cd "$BUILDDIR/obj_gcc"
make -j$(nproc)
make -j$(nproc) install DESTDIR="$INSTALLDIR"

# set /lib64/ld-linux-aarch64.so.1 as ELF interpreter
$INSTALLDIR/bin/${TARGET}-gcc -dumpspecs > $BUILDDIR/specs
sed -e 's;/lib/ld-linux-aarch64;/lib64/ld-linux-aarch64;g' -i $BUILDDIR/specs

# Use aarch64-linux-gnu-as instead of generic `as`
sed -e "/^[*]invoke_as:/,/^[*]cpp:/ s; as ; ../../../../bin/${TARGET}-as ;" -i $BUILDDIR/specs
# Same for objcopy
sed -e "s; objcopy ; ../../../../bin/${TARGET}-objcopy ;" -i $BUILDDIR/specs

mv $BUILDDIR/specs "$INSTALLDIR/lib/gcc/$TARGET/${GCC_MAJOR_VERSION}/"

# relocate libgcc_s
mv $INSTALLDIR/lib/gcc/$TARGET/lib64/libgcc_s.so* "$INSTALLDIR/lib/gcc/$TARGET/${GCC_MAJOR_VERSION}/"
rmdir "$INSTALLDIR/lib/gcc/$TARGET/lib64"