GNU Toolchain for ARM

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Build ARM Toolchain Step by Step
Thanks to David McCullough's elf2flt patch for the ARM platforms, the userland applications for uClinux do not need the -mdisable-got flag any more.

1. Build binutils ...
   Download the binutils-2.10.tar.gz

   # tar zxvf binutils-2.10.tar.gz
   # cd binutils-2.10
   # mkdir build
   # cd build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu
   
   # make
   # make install [Note: write access to /usr/local/gnu is required]

2. Build gcc ...
   Download the gcc-2.95.3.tar.gz

   # tar zxvf gcc-2.95.3.tar.gz

   Apply patch from Philip Blundell to change the Position Independent Code generation for ARM:

   # gzip -cd gcc-2.95.3-arm-pic.patch.gz | patch -p0

   # cd gcc-2.95.3
   # mkdir build
   # cd build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu --disable-threads
   # make LANGUAGES="c" [Note: be sure /usr/local/gnu/bin is in the PATH list]
                 

   Since this is the first time you have built a cross-compiler on your host, the C runtime startup file does not exist, so you will get the error like this:

   make[1]: Leaving directory `/home/tzeng/gcc-2.95.3/build/gcc'
   Configuring in arm-elf/libio
   ...
   checking whether the C compiler (/home/tzeng/gcc-2.95.3/build/gcc/xgcc
    -B/home/tzeng/gcc-2.95.3/build/gcc/ -B/usr/local/gnu/arm-elf/bin/ -g -O2 )
    works... no
   configure: error: installation or configuration problem: C compiler cannot
    create executables.

   continue installing the C compiler only:

   # cd gcc
   # make install

3. Build libc ...
   Download the newlib.tar.gz

   # tar zxvf newlib.tar.gz
   # cd newlib-1.8.1
   # mkdir build
   # cd build

   You may choose ARM_RDI_MONITOR in ../newlib/configure.in to select Angel monitor support now.

   # ../configure --target=arm-elf --prefix=/usr/local/gnu 
                  --enable-target-optspace
   # make
   # make install

4. Build other languages supports in gcc ...
   

   # cd gcc-2.95.3/build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu
   # make LANGUAGES="c c++"
   # make install

1. Build binutils ...
   Download the binutils-2.10.tar.gz

   # tar zxvf binutils-2.10.tar.gz
   # cd binutils-2.10
   # mkdir build
   # cd build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu
   
   # make
   # make install [Note: write access to /usr/local/gnu is required]

2. Build gcc ...
   Download the gcc-3.0.1.tar.gz

   # tar zxvf gcc-3.0.1.tar.gz

   Apply patch to enable fpu, thumb interworking multilib. [Optional]

   # gzip -cd gcc-3.0.1-thumb-interwork.patch.gz | patch -p0

   # cd gcc-3.0.1
   # mkdir build
   # cd build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu --disable-threads
                  --with-newlib --disable-shared --enable-languages=c
   # make [Note: be sure /usr/local/gnu/bin is in the PATH list]
   # make install

3. Build libc ...
   Download the newlib.tar.gz

   # tar zxvf newlib.tar.gz

   Apply patch to fix type conversion for signal library.

   # gzip -cd newlib-1.8.1-gcc3.patch.gz | patch -p0
   # cd newlib-1.8.1
   # mkdir build
   # cd build

   You may choose ARM_RDI_MONITOR in ../newlib/configure.in to select Angel monitor support now.

   # ../configure --target=arm-elf --prefix=/usr/local/gnu 
                  --enable-target-optspace
   # make
   # make install

4. Build other languages supports in gcc ...
   

   # cd gcc-3.0.1/build
   # ../configure --target=arm-elf --prefix=/usr/local/gnu --disable-threads
                  --with-newlib --disable-shared --enable-languages=c,c++
   # make
   # make install

Whatever target name you build gcc for, the main code engine still contains support for all the different ARM variations (i.e. it's the same whatever target name you build with). However, there is a library accompanying gcc, containing some fundamental support routines, called libgcc.a. This is the thing that will differ between different target names, and this is what makes different toolchains binary incompatible.

• Why the need of 'no-got' or 'disable-got' gcc flag?
  To generate relocatable FLAT userland programs for uClinux, the $(LD) has to emit reloc informations:

  LDFLAGS	ELF Type	Reloc Info.	Has GOT	Solve Undef.
  	EXEC(Executable file)	No(1)	Yes	Yes
  -r	REL(Relocatable file)	Yes	No(2)	No
  -shared	DYN(Shared Object File)	Yes	Yes(3)	No

  Note1: Reloc info. are absolutely required as below:

              void (*foo)(char*);
              char *str = "Hello";  /* will be in .data */
              ...
              { ...
                (*foo)(str);
  
              ldr   r3,[pc,#18]     /* offset into GOT */
              ldr   r3,[r9,r3]      /* addr of 'str' */
              ldr   r0,[r3]         /* addr of "Hello" has to be relocated */

  Note2: Due to .got doesn't exist in REL files, the 'elf2flt' is unable to put GOT entries into the flat image.
  Note3: Aplio use it! To be digged into further.

• What are the differences between those arm-gcc?
  

  Filename	Location	Version	Features	Frame-pointer Bug
  arm-tools-src.tgz	aplionet.aplio.fr	v2.96 20000519	disable-got thumb	Infected
  egcs.tar.gz	www.uclinux.org	v2.96 20000417	disable-got	Infected
  Vadim Lebedev's patch			no-got	Infected