Building ARM toolchain - part 2: gcc and eglibc

Unfortunately after few tries of cross compiling eglibc using different source for instructions I alway end with hard to solve issues. Luckily, in the sources of eglibc I noticed instructions for cross-compiling written long time ago by Jim Blandy(I know i should start here). Lot of thanks to him for it. Below I describe my expierence which I gained during eglibc cross cpomliation for arm-unknown-linux-gnueabi and procedure that I used. Commands below contain some constants that I used in previous works. See this post. Eglibc library and the compiler itself is built with many various parameters this post is not the place to explain their meaning, please RTFM.

1. Checkout eglibc from svn (as alwyas I try to use a latest sources possible). Version used r17815:

   svn co http://www.eglibc.org/svn/trunk eglibc

2. Link working ports to GNU/Linux on some machine architectures. They are not maintained in the official glibc source tree so we need to add it in this way:

   ln -s ../ports eglibc/libc/ports/

3. Create eglibc-headers directory:

   mkdir eglib-headers; cd eglib-headers

4. Configure eglibc and preliminary objects:

   BUILD_CC=gcc CC=arm-unknown-linux-gnueabi-gcc CXX=arm-unknown-linux-gnueabi-cpp \
   AR=arm-unknown-linux-gnueabi-ar RANLIB=arm-unknown-linux-gnueabi-ranlib \
   ../eglibc/libc/configure --prefix=/usr --with-headers=$TARGET/usr/include \
   --build=x86_64-pc-linux-gnu --host=arm-unknown-linux-gnueabi --disable-profile \
   --without-gd --without-cvs --enable-add-ons

5. Install eglibc headers:

   make install-headers install_root=$TARGET install-bootstrap-headers=yes

6. We need few object file to link shared libraries, which will be built and installed by hand:

   mkdir -p $TARGET/usr/lib
   make csu/subdir_lib
   cp csu/crt1.o csu/crti.o csu/crtn.o $TARGET/usr/lib

7. To produce libgcc_s.so we need libc.so, but only need its dummy version because we'll never use it. It doesn't matter what we will point as a libc.so we use /dev/null as C file.

   arm-unknown-linux-gnueabi-gcc -nostdlib -nostartfiles -shared -x c /dev/null -o \
   $TARGET/usr/lib/libc.so

8. Get latest gcc sources using git repository mirror. Latest commit while writing this post was 5b9a8c3:

   cd ..
   git clone git://repo.or.cz/official-gcc.git

9. Now, we can build gcc which can compile eglibc.

   mkdir eglibc-gcc; cd eglibc-gcc
   ../official-gcc/configure --target=arm-unknown-linux-gnueabi \
   --prefix=$TARGET/arm-x-tools --with-sysroot=$TARGET --disable-libssp \
   --disable-libgomp --disable-libmudflap --enable-languages=c \
   --with-gmp=$TARGET/arm-x-tools --with-mpfr=$TARGET/arm-x-tools \
   --with-mpc=$TARGET/arm-x-tools --disable-libquadmath --build=$MACHTYPE \
   --host=$MACHTYPE --with-local-prefix=$TARGET/arm-x-tools --disable-multilib \
   --with-float=soft --with-pkgversion="pietrushnic" --enable-threads=no \
   --enable-target-optspace --disable-nls --enable-c99 --enable-long-long
   make -j4
   make install

10. Confugure and compile final version of eglibc.

    mkdir eglibc-final
    cd eglibc-final/
    BUILD_CC=gcc CC=arm-unknown-linux-gnueabi-gcc CXX=arm-unknown-linux-gnueabi-cpp \
    AR=arm-unknown-linux-gnueabi-ar RANLIB=arm-unknown-linux-gnueabi-ranlib \
    ../eglibc/libc/configure --prefix=/usr --with-headers=$TARGET/usr/include \
    --build=x86_64-pc-linux-gnu --host=arm-unknown-linux-gnueabi --disable-profile \
    --without-gd --without-cvs --enable-add-ons
    make
    make install install_root=$TARGET

11. Install libelf library

    wget http://www.mr511.de/software/libelf-0.8.13.tar.gz
    tar zxvf libelf-0.8.13.tar.gz
    cd libelf-0.8.13/
    ./configure  --prefix=$TARGET/arm-x-tools --disable-shared --enable-static
    make;make install

12. Prepare final version of gcc.

    cd ..
    mkdir final-gcc
    cd final-gcc
    ../official-gcc/configure --target=arm-unknown-linux-gnueabi \
    --prefix=$TARGET/arm-x-tools --with-sysroot=$TARGET --disable-libssp \
    --disable-libgomp --disable-libmudflap --enable-languages=c,c++ 
    --with-gmp=$TARGET/arm-x-tools --with-mpfr=$TARGET/arm-x-tools 
    --with-mpc=$TARGET/arm-x-tools --disable-libquadmath --build=$MACHTYPE \
    --host=$MACHTYPE --with-local-prefix=$TARGET/arm-x-tools --disable-multilib \
    --with-float=soft --with-pkgversion="pietrushnic" --enable-threads=posix \
    --enable-target-optspace --disable-nls --enable-c99 --enable-long-long \
    --enable-__cxa_atexit --enable-symvers=gnu --with-libelf=$TARGET/arm-x-tools \
    --enable-lto
    make
    make install

13. Few libraries should be copied manualy

    cp -d $TARGET/arm-x-tools/arm-unknown-linux-gnueabi/lib/libgcc_s.so* $TARGET/lib
    cp -d $TARGET/arm-x-tools/arm-unknown-linux-gnueabi/lib/libstdc++.so* $TARGET/lib

14. Compile and install chrpath - this is useful tool to remove the rpath or runpath setting from binary.

    cd ..
    sudo apt-get install libc6-i386 gcc-multilib
    apt-get source chrpath
    cd chrpath-0.13/
    CFLAGS=-m32 ./configure --prefix=$TARGET/arm-x-tools \
    --program-prefix=arm-unknown-linux-gnueabi-
    make
    make install

15. Strip debug symbols

    strip --strip-debug $TARGET/arm-x-tools/lib/* \
    $TARGET/arm-x-tools/arm-unknown-linux-gnueabi/lib/* $TARGET/arm-x-tools/libexec/*
    

    strip --strip-unneeded $TARGET/arm-x-tools/bin/* \
    $TARGET/arm-x-tools/arm-unknown-linux-gnueabi/bin/*

    arm-unknown-linux-gnueabi-strip --strip-debug $TARGET/lib/* $TARGET/usr/lib/*

16. At the end simple test to find out if basic functionality works:

    $ cat > hello.c <<EOF
    > #include <stdio.h>
    > int
    > main (int argc, char **argv)
    > {
    >   puts ("Hello, world!");
    >   return 0;
    > }
    > EOF
    

    Try to cross compile C file:

    $TARGET/arm-x-tools/bin/arm-unknown-linux-gnueabi-gcc -Wall hello.c -o hello
    

    $ cat > c++-hello.cc <<EOF
    > #include <iostream>
    > int
    > main (int argc, char **argv)
    > {
    >   std::cout << "Hello, C++ world!" << std::endl;
    >   return 0;
    > }
    > EOF
    

    Try to cross compile C++ file:

    $TARGET/arm-x-tools/bin/arm-unknown-linux-gnueabi-g++ -Wall c++-hello.cc -o \
    c++-hello
    

    Displays the information contained in the ELF header and in the file's segment headers:

    $TARGET/arm-x-tools/bin/arm-unknown-linux-gnueabi-readelf -hl hello
    $TARGET/arm-x-tools/bin/arm-unknown-linux-gnueabi-readelf -hl c++-hello
    

    Result should look like that:

    ELF Header:
      Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
      Class:                             ELF32
      Data:                              2's complement, little endian
      Version:                           1 (current)
      OS/ABI:                            UNIX - System V
      ABI Version:                       0
      Type:                              EXEC (Executable file)
      Machine:                           ARM
      (...)
      Flags:                             0x5000002, has entry point, Version5 EABI
      (...)
    Program Headers:
      (...)
      INTERP         0x000134 0x00008134 0x00008134 0x00013 0x00013 R   0x1
          [Requesting program interpreter: /lib/ld-linux.so.3]
      LOAD           0x000000 0x00008000 0x00008000 0x004b8 0x004b8 R E 0x8000
      (...)
    

    $TARGET/arm-x-tools/bin/arm-unknown-linux-gnueabi-readelf -d \
    $TARGET/lib/libgcc_s.so.1

    Result should look like that:

      (...)
      Tag        Type                         Name/Value
     0x00000001 (NEEDED)                     Shared library: [libc.so.6]
     0x0000000e (SONAME)                     Library soname: [libgcc_s.so.1]
     0x0000000c (INIT)                       0xcc2c
      (...)
    

I hope you find above manual useful. If you need more detailed descriptions it can be found here. Also don't bother to ask me by comment below.