Toolchains

This guide will help you through the steps to build a toolchain for the architectures of the platforms you want to use.

Prerequisites

All of the common prerequisites apply.

Requirements

• Access to an embEDUx buildserver system

• User Documentation.

  • At the end of the setup, the Administrator is instructed to create the User Documentation.

• toolchain-specs Git-Repository

  The toolchain-specification is supplied to the buildserver via git. Consult your User Documentation for the repository URLs. (See previous link)

• Crosstool NG ct-ng locally installed.

Suggestions

• Have a look at the default build script. As the buildserver just executes these scripts, you have no limits on what you want to do before, during and after the build process.
• As you will use or at least configure Crosstool-NG, you should make yourself comfortable in using it.

Branch Name-Scheme

The builserver can only build your images, if you follow the correct name-scheme for the branches.

The variables that are needed for your platform can be found in the User Documentation.

Variables

Variable	Notes
host-arch	Architecture of the host system (where the toolchain is used)
target-arch	Specified and mapped to the target architecture by the Administrator. Found in the User Documentation
abi	Application Binary Interface (selected by toolchain configuration)

Branches

Branch	Scheme	Example
toolchain	< host-arch >_< target-arch >-ctng-linux-< abi >	armv6j-ctng-linux-gnueabi

Step-by-Step Example

The following example will give you a detailed overview of the necessary steps to build the toolchain for the raspberry pi (armv6j). We assume that at this point the toolchains-specs repository is empty.

Add A New Toolchain

1. Clone the toolchains-specs repository with the URL provided in the user documentation.

   $ git clone git@apu.in.htwg-konstanz.de:labworks-embEDUx/toolchains.git

2. Add a toolchain branch to the toolchains-specs repository. It is necessary that you push the branch at this point upstream, so the buildserver can find the new toolchain branch.

   $ git checkout master $ git branch amd64_armv6j-ctng-linux-gnueabi $ git checkout amd64_armv6j-ctng-linux-gnueabi $ touch README.md $ git add README.md $ git commit -m "inital commit" $ git push --set-upstream origin amd64_armv6j-ctng-linux-gnueabi

3. Add the default build script as build to the branch and make it executable.

   $ ls -hl

   total 4.0K
   -rwxr-xr-x 1 user user 470 Mar  3 20:52 build
   -rw-r--r-- 1 user user   0 Mar  3 20:51 README
   

4. Configure your desired toolchain with ct-ng and add the .config to the branch. In this example we will just use a sample configuration (ct-ng armv6-rpi-linux-gnueabi) and modify the configuration, to build a static toolchain. For further information read background/toolchains.

   The parameters for a static toolchain should be set as following:

   • Disable progress bar (otherwise build.log ends up beeing huge)
     • CT_LOG_PROGRESS_BAR is not set
   • Storage directory
     • CT_LOCAL_TARBALLS_DIR="/var/tmp/embedux/download"
     • CT_SAVE_TARBALLS=y
   • Output directory for ctng
     • CT_PREFIX_DIR="${CT_TOP_DIR}/output/${CT_TARGET}"
   • Static toolchain
     • CT_STATIC_TOOLCHAIN=y and all dependencies
     • CT_CC_STATIC_LIBSTDCXX=y
     • CT_GDB_CROSS_STATIC=y
     • CT_BINUTILS_LINKERS_LIST="ld" (building static toolchain doesn't work with gold)

5. Test your toolchain configuration

   $ ct-ng build

6. Add changes, commit and push them upstream.

   $ git add build $ git commit -m "new toolchain for amd64 -> armv6j" $ git push

7. The buildserver should start building your toolchain now. For further informations on how to monitor the build check monitoring guide.

8. Congratulations, you just built your first toolchain for the platform architecture. Find the toolchain product download URL in the User Documentation (see Hardware Deployment).