Compiler wrapper

See the comments on the top of main.go. Build is split into 2 steps via separate commands:

  • bundle: copies the sources and the build.py file into a folder.
  • build: builds the actual go binary, assuming it is executed from the folder created by bundle.py.

This allows to copy the sources to a ChromeOS / Android package, including the build script, and then build from there without a dependency on toolchain-utils itself.

Testing Inside the Chroot

To test updates to the wrapper locally:

Run install_compiler_wrapper.sh to install the new wrapper in the chroot:

(chroot) ~/trunk/src/third_party/toolchain-utils/compiler_wrapper/install_compiler_wrapper.sh

Then perform the tests, e.g. build with the new compiler.

Updating the Wrapper for ChromeOS

To update the wrapper for everyone, the new wrapper configuration must be copied into chromiumos-overlay, and new revisions of the gcc and llvm ebuilds must be created.

Copy over sources and build.py to chromiumos-overlay:

(chroot) /mnt/host/source/src/third_party/chromiumos-overlay/sys-devel/llvm/files/update_compiler_wrapper.sh

Rename chromiumos-overlay/sys-devel/llvm/llvm-${VERSION}.ebuild to the next revision number. For example, if the current version is 11.0_pre394483_p20200618-r2:

(chroot) cd ~/trunk/src/third_party/chromiumos-overlay
(chroot) git mv llvm-11.0_pre394483_p20200618-r2.ebuild llvm-11.0_pre394483_p20200618-r3.ebuild

Rename chromiumos-overlay/sys-devel/gcc/gcc-${VERSION}.ebuild to the next revision number. For example, if the current version is 10.2.0-r3:

(chroot) cd ~/trunk/src/third_party/chromiumos-overlay
(chroot) git mv sys-devel/gcc/gcc-10.2.0-r3.ebuild sys-devel/gcc/gcc-10.2.0-r4.ebuild

Commit those changes together with the changes made by update_compiler_wrapper.sh.

The changes can then be reviewed and submitted through the normal process.

Paths

build.py is called by these ebuilds:

  • third_party/chromiumos-overlay/sys-devel/llvm/llvm-*.ebuild
  • third_party/chromiumos-overlay/sys-devel/gcc/gcc-*.ebuild

Generated wrappers are stored here:

  • Sysroot wrapper with ccache: /usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/10.2.0/sysroot_wrapper.hardened.ccache
  • Sysroot wrapper without ccache: /usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/10.2.0/sysroot_wrapper.hardened.noccache
  • Clang host wrapper: /usr/bin/clang_host_wrapper
  • Gcc host wrapper: /usr/x86_64-pc-linux-gnu/gcc-bin/10.2.0/host_wrapper