compiler_wrapper: Updated instructions for updating the wrapper
This change adds some more details on how to test and commit
changes to the compiler wrapper.
BUG=None
TEST=Followed the steps locally to verify that they work.
Change-Id: I5a3d644e92fd94ed3792a59a30f39db08053390d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2305371
Commit-Queue: Bob Haarman <inglorion@chromium.org>
Tested-by: Bob Haarman <inglorion@chromium.org>
Reviewed-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Jian Cai <jiancai@google.com>
diff --git a/compiler_wrapper/README.md b/compiler_wrapper/README.md
index e64f01b..e55bb66 100644
--- a/compiler_wrapper/README.md
+++ b/compiler_wrapper/README.md
@@ -12,31 +12,72 @@
build from there without a dependency on toolchain-utils
itself.
-## Update source files
+## Testing Inside the Chroot
-Copy over sources and `build.py` to Chrome OS:
+To test updates to the wrapper locally:
+
+Run `install_compiler_wrapper.sh` to install the new wrapper in the chroot:
```
-(chroot) /mnt/host/source/src/third_party/chromiumos-overlay/sys-devel/llvm/files/update\_compiler\_wrapper.sh
+(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 Chrome OS
+
+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 4.9.2-r254:
+```
+(chroot) cd ~/trunk/src/third_party/chromiumos-overlay
+(chroot) git mv sys-devel/gcc/gcc-4.9.2-r254.ebuild sys-devel/gcc/gcc-4.9.2-r255.ebuild
+```
+
+Edit the new ebuild file and change the number at the end to match the new revision:
+```
+-# If you need to force a cros_workon uprev, change this number (you can use next
+-# uprev): 254
++# If you need to force a cros_workon uprev, change this number (you can use next
++# uprev): 255
+```
+
+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-11.0\_pre394483\_p20200618-r3.ebuild
-- third_party/chromiumos-overlay/sys-devel/gcc/gcc-\*.ebuild
+- third_party/chromiumos-overlay/sys-devel/llvm/llvm-*.ebuild
+- third_party/chromiumos-overlay/sys-devel/gcc/gcc-*.ebuild
-## Update compiler wrappers
-```
-(chroot) /mnt/host/source/src/third|_party/toolchain-utils/compiler\_wrapper/install\_compiler\_wrapper.sh
-```
Generated wrappers are stored here:
- Sysroot wrapper with ccache:
- `/usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/4.9.x/sysroot\_wrapper.hardened.ccache`
+ `/usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/4.9.x/sysroot_wrapper.hardened.ccache`
- Sysroot wrapper without ccache:
- `/usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/4.9.x/sysroot\_wrapper.hardened.noccache`
+ `/usr/x86_64-pc-linux-gnu/<arch>/gcc-bin/4.9.x/sysroot_wrapper.hardened.noccache`
- Clang host wrapper:
- `/usr/bin/clang\_host\_wrapper`
+ `/usr/bin/clang_host_wrapper`
- Gcc host wrapper:
- `/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.x/host\_wrapper`
-
-
+ `/usr/x86_64-pc-linux-gnu/gcc-bin/4.9.x/host_wrapper`
