ARM EABI Toolchain Builder

This toolchain builder builds a GCC and Newlib-based ARM EABI toolchain using the Sourcery CodeBench Lite sources. This Makefile was originally created to allow building a validated GCC release on Mac OS X, as CodeBench Lite / G++ Lite were only provided for Windows and Linux, but this build also includes some optimizations for Newlib that provide smaller binaries.

NOTE: Mentor have indicated that there won't be future ARM EABI releases of the free Lite edition of CodeBench, so the 2014.05 release may be the last. You may also be able to use a modified version of this makefile with the sources Mentor provides with the Professional version of CodeBench (which they plan to continue supporting). If future source releases are made available, this Makefile will be updated for them. If not, we may start to build custom versions of other GCC/Newlib toolchain sources.

This build system has been tested on Mac OS X 10.10.1. Small modifications may be needed in order to make it work with other platforms.

Note: If you have previously built a toolchain of another version, out of the same builder directory, make sure to do the following first before building with newer sources:

make clean

Also, make sure that you don't have another arm-non-eabi-[gcc,g++,ld,gdb] etc toolchain in your path when you build, whether it is a previous version of this same toolchain or a binary toolchain from another provider. This may end up influencing how newlib, in particular, gets compiled.

Requirements (OS X)

You will need to have clang, make, binutils installed on your machine to compile all of this. You can get most of these on Mac OS X, by just installing the Apple Developer Tools which are free here.

For Xcode 4.3 or later, the command line tools are no longer bundled by default, and there is no /Developer anymore. To install them, open Xcode, go to Preferences -> Downloads -> Components -> Command Line Tools. This should install make, gcc etc.

You will also need libelf and texinfo first. I recommend installing these from homebrew.

With homebrew you can install those dependencies like this:

brew install libelf texinfo

Requirements (Ubuntu)

These instructions should now also work on Ubuntu Linux, provided the following packages have been installed prior to attempting the build:

sudo apt-get install curl flex bison texinfo \
      libelf-dev autoconf build-essential libncurses5-dev \

Main Build Instructions

Next build the toolchain:

make install-cross

Note: My most recent test on Mac OS X 10.8 with XCode Command Line Tools from April 2013, it was necessary to use the instructions in the Installing gcc-4.2 section.

You should be able to also specify a specific install/prefix location by building using the following type of invokation:

PREFIX=$HOME/arm-cs-tools make install-cross

By default the build attempts to determine the number of CPUs and sets the number of parallel jobs automatically (Linux & OS X). If you're on another platform or want to use a different number of jobs, you can redefine PROCS:

PROCS=8 make install-cross

NOTE: If you are on Mac OS X and are running XCode 4.1 or a similar version and are trying to build 2011.03 or an earlier version of CodeSourcery's sources, you may find that it will fail during the build of libgcc as discussed in issue #10. To work around this, build using using these two commands instead of the above:

CC=clang make cross-binutils cross-gcc cross-newlib

make cross-gdb

or with gcc-4.2:

CC=gcc-4.2 make install-cross

*NOTE: GCC 4.2 has been removed from recent versions of Apple's Command Line Tools for XCode, if you *need this compiler you'll have to follow instructions in the gcc 4.2 section below.

This should build the compiler, newlib, gdb, etc.. and install them all into a directory called arm-cs-tools in your home directory. If you want to install to another location, feel free to change the export lines and to adjust the definitions at the top of the Makefile.

Keep in mind that the Makefile does install at the end of each build.

Once you’re done, you’ll likely want to add the path where the compiler was installed to to your .bash_profile, .zshrc, etc..:

export PATH=$HOME/arm-cs-tools/bin:$PATH

To clean up when you're done and you've installed the toolchain you can clean up the intermediate files with the following command:

make clean

Installing gcc-4.2

First things first, see if it is installed. Write gcc in your commandline and double tab. If there is no file called gcc-4.2 you most likely do not have it. One more check though is to check the gcc version by doing gcc -v. Look at the last line of the output, if it looks like this

gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)

you may think you are in luck and you have gcc-4.2. Unfortunately it is not that simple. This is the llvm version of gcc-4.2 from Apple and unfortunately does not work with the latest CodeSourcery packages.

The correct gcc version is easy to install though using homebrew.

brew tap homebrew/dupes && brew install apple-gcc42

and then do

CC=gcc-4.2 make install-cross

###Note: Homebrew-Dupes also offers a gcc formula which installs, at the time of this writing, GCC 4.7. I have not tried this version myself but might be worth a try since 4.2 is getting pretty dated.

Multilib Build Customization

By default, the toolchain will build with the the multilibs included in the binary builds of G++ Lite. If you want to build multilibs for a larger set of targets similar to the commercial release, you can build like this:

FULL_MULTILIBS=true make install-cross

NOTE: Building with this option will take significantly longer.

Newlib Build Customization

By default, this build enables a number of extra optimizations (most of which relate to reducing code size) for Newlib by defining the following:

CFLAGS_FOR_TARGET="\
 -ffunction-sections -fdata-sections          \ # put code and data into separate sections allowing for link-time
 -DPREFER_SIZE_OVER_SPEED -D__OPTIMIZE_SIZE__ \ # pick simpler, smaller code over larger optimized code
 -Os                                          \ # same as O2, but turns off optimizations that would increase code size
 -fomit-frame-pointer                         \ # don't keep the frame pointer in a register for functions that don't need one
 -fno-unroll-loops                            \ # don't unroll loops
 -D__BUFSIZ__=256                             \ # limit default buffer size to 256 rather than 1024
 -mabi=aapcs"                                 \ # enable use of arm procedure call standard (not sure if this is needed any more)
CCASFLAGS=$(CFLAGS_FOR_TARGET)

For an example of what the PREFER_SIZE_OVER_SPEED and __OPTIMIZE_SIZE__ options do, take a look at the following memcpy.c extracted from newlib. Often what one is giving up is manually unrolled loops or hand-coded assembler that compiles to sizes larger than a simple C implementation.

If you want something closer to standard options that CodeSourcery uses simply prepend the make command as follows:

MATCH_CS=true make install-cross

For Newlib this changes the flags to these:

CFLAGS_FOR_TARGET="-g -O2 -fno-unroll-loops"

You can also define your own Newlib flags:

NEWLIB_FLAGS="-g -O2 -fno-unroll-loops" make install-cross

Additionally, there is an option to exclude float support from Newlib functions. At the moment this should disable float support for IO functions:

NEWLIB_NOFLOAT=true make install-cross

Extras From Binary Distribution

Some of the CodeSourcery CS3 libraries are distributed with G++ Lite, but the sources for these are not made available, nor are the licensing terms in the binary release of G++ Lite permissive of my including a small compressed download of these libraries with this build file. However, I have added a make target that should be able to pull down the binary Linux tarball extract these libraries and a few extras, and place them into the correct directories. To use this, type the following after you have installed your toolchain:

make install-bin-extras

If you need the binary extras installed at a specific prefix, you can use the following style of incantation:

PREFIX=/some/other/location make install-bin-extras

So, if you had placed your pre-built binaries at /usr/local/arm-cs-tools, you could use the following:

PREFIX=/usr/local/arm-cs-tools make install-bin-extras

NOTE: use of these libraries is untested by the creator of the Makefile. It seemed simple enough to add this after a user had mentioned a desire to have these libraries available.

Special Thanks

• Rob Emanuele for the basis of this Makefile as a starting point.

• Liviu Ionescu for numerous comments suggestions/suggestions and fixes.