meta-external-toolchain/README.md

OpenEmbedded/Yocto layer for the Sourcery G++ toolchain

Usage & Instructions

• Ensure that you have the Sourcery G++ toolchain installed.

• If it's an ia32 toolchain, make sure you did not let it modify your PATH, and if you did, remove it.

  This is necessary because the ia32 Sourcery G++ toolchain shipped non-prefixed binaries (e.g. gcc rather than i586-none-linux-gcc), which means bitbake would be unable to run the host's gcc directly anymore.

• Add the meta-sourcery layer to your BBLAYERS in conf/bblayers.conf. Please make certain that it is listed before the meta layer, as this ensures meta-sourcery gets priority over meta.

• Set EXTERNAL_TOOLCHAIN = "/path/to/your/sourcery-g++-install" in conf/local.conf.

Optional Functionality

• If the user chooses to, they may optionally decide to rebuild the Sourcery G++ eglibc from source, if they have downloaded the corresponding source archive from Mentor Graphics. To so, set TCMODE = "external-sourcery-rebuild-libc", rather than relying on the default value of external-sourcery.

Description of Behavior

The meta-sourcery layer.conf automatically defines TCMODE for us, so this is no longer necessary. The tcmode performs a number of operations:

• Sets TARGET_PREFIX appropriately, after determining what prefix is in use by the toolchain
• Sanity checks EXTERNAL_TOOLCHAIN: does the path exist? does the expected sysroot exist?
• Sanity checks execution of the toolchain binaries
• Sets preferences so that the external-sourcery-toolchain recipe is used in preference to rebuilding various things from source with their own recipes
• Extracts version information from the toolchain (e.g. by running ${TARGET_PREFIX}gcc -v), for use in the external-sourcery-toolchain recipe and its binary packages
• Symlinks the toolchain binaries into the toolchain portion of the sysroot. This is done in preference to adding the toolchain path to the PATH, to avoid the aforementioned ia32 issue, and to let us work around certain issues (For example, we create an ld.bfd link which the kernel build expects, but isn't shipped with the toolchain)
• Adds the external toolchain PATH to the setup script emitted when building SDKs (e.g. when bitbaking meta-toolchain)
• Sets GCCVERSION to the gcc version of the toolchain, to prefer a matching gcc version for the target package, if possible. Certain versions of gcc have trouble being built by other versions of gcc, so this can avoid such issues.

Contributing

URL: https://github.com/MentorEmbedded/meta-sourcery

To contribute to this layer, please fork and submit pull requests to the above repository with github, or open issues for any bugs you find, or feature requests you have.

Content review

• Fix GNU_HASH warnings / obey LDFLAGS

  • imx-lib
  • blktrace
  • hostap
  • gdbm
  • setserial
  • irda-utils
  • python
  • perl