a41c3c45fd
This is a reland of commit6f00b586ddOriginal change's description: > Reland "Migrate rust hook to deps and create sync_deps.py" > > This is a reland of commit2af7751ec4, with the > following changes: > * update_rust - use VERSION instead of INSTALLED_VERSION > > gclient ensures that the rust package is not partially extracted, so > INSTALLED_VERSION is no longer needed. > > > Original change's description: > > Migrate rust hook to deps and create sync_deps.py > > > > After someone runs upload_revision.py, triggers the packager bots, > > and manually copies the packages to prod, they will now run > > sync_deps.py to update the DEPS file. After doing that they can > > trigger a CQ run to test the new packages. > > > > Bug: b/338612245 > > Change-Id: Ie95efbf2049e651192d52ca7531c20125b3dd537 > > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5536220 > > Reviewed-by: Hans Wennborg <hans@chromium.org> > > Commit-Queue: Josip Sokcevic <sokcevic@chromium.org> > > Cr-Commit-Position: refs/heads/main@{#1304616} > > Bug: b/338612245 > Change-Id: I2038e57a2e767eea10df6e2b72b6d2e2344d630e > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5560825 > Reviewed-by: Hans Wennborg <hans@chromium.org> > Commit-Queue: Josip Sokcevic <sokcevic@chromium.org> > Reviewed-by: danakj <danakj@chromium.org> > Cr-Commit-Position: refs/heads/main@{#1305165} Bug: b/338612245 Change-Id: I597a7ee0e894109e34cd374bf20d270a01705354 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5569382 Commit-Queue: Josip Sokcevic <sokcevic@chromium.org> Reviewed-by: Hans Wennborg <hans@chromium.org> Cr-Commit-Position: refs/heads/main@{#1308016}
88 lines
4.2 KiB
Markdown
88 lines
4.2 KiB
Markdown
# Updating clang
|
|
|
|
We distribute prebuilt packages of LLVM binaries, including clang and lld, that
|
|
all developers and bots pull at `gclient runhooks` time. These binaries are
|
|
just regular LLVM binaries built at a fixed upstream revision. This document
|
|
describes how to build a package at a newer revision and update Chromium to it.
|
|
An archive of all packages built so far is at https://is.gd/chromeclang
|
|
|
|
1. Check that https://ci.chromium.org/p/chromium/g/chromium.clang/console
|
|
looks reasonably green. Red bots with seemingly normal test failures are
|
|
usually ok, that likely means the test is broken with the stable Clang as
|
|
well.
|
|
1. Sync your Chromium tree to the latest revision to pick up any plugin
|
|
changes.
|
|
1. Run [go/chrome-push-clang-to-goma](https://goto.google.com/chrome-push-clang-to-goma).
|
|
This takes a recent dry run CL to update clang, and if the trybots were
|
|
successful it will copy the binaries from the staging bucket to the
|
|
production one. Writing to this bucket requires special permissions. File a
|
|
bug at g.co/bugatrooper if you don't have these already (e.g.,
|
|
https://crbug.com/1034081). Then it will push the packages to RBE. If you
|
|
do not have the necessary credentials to do the upload, ask
|
|
clang@chromium.org to find someone who does.
|
|
* Alternatively, to create your own roll CL, you can manually run
|
|
`tools/clang/scripts/upload_revision.py` with a recent upstream LLVM
|
|
commit hash as the argument. After the `*_upload_clang` trybots are
|
|
successfully finished, run
|
|
[go/chrome-promote-clang](https://goto.google.com/chrome-promote-clang)
|
|
on the new Clang package name.
|
|
1. Run `tools/clang/scripts/sync_deps.py` to update the deps entries in DEPS.
|
|
1. Run an exhaustive set of try jobs to test the new compiler. The CL
|
|
description created previously by upload_revision.py includes
|
|
`Cq-Include-Trybots:` lines for all needed bots, so it's sufficient to just
|
|
run `git cl try` (or hit "CQ DRY RUN" on gerrit).
|
|
1. Commit the roll CL from the previous step.
|
|
1. The bots will now pull the prebuilt binary, and RBE will have a matching
|
|
binary, too.
|
|
|
|
## Performance regressions
|
|
|
|
After doing a clang roll, you may get a performance bug assigned to you
|
|
([example](https://crbug.com/1094671)). Some performance noise is expected
|
|
while doing a clang roll.
|
|
|
|
You can check all performance data for a clang roll via
|
|
`https://chromeperf.appspot.com/group_report?rev=XXXXXX`, where `XXXXXX` is the
|
|
revision number, e.g. `778090` for the example bug (look in the first message
|
|
of the performance bug to find this). Click the checkboxes to display graphs.
|
|
Hover over points in the graph to see the value and error.
|
|
|
|
Serious regressions require bisecting upstream commits (TODO: how to repro?).
|
|
If the regressions look insignificant and there is green as well as red, you
|
|
can close the bug as "WontFix" with an explanation.
|
|
|
|
## Adding files to the clang package
|
|
|
|
The clang package is downloaded unconditionally by all bots and devs. It's
|
|
called "clang" for historical reasons, but nowadays also contains other
|
|
mission-critical toolchain pieces besides clang.
|
|
|
|
We try to limit the contents of the clang package. They should meet these
|
|
criteria:
|
|
|
|
- things that are used by most developers use most of the time (e.g. a
|
|
compiler, a linker, sanitizer runtimes)
|
|
- things needed for doing official builds
|
|
|
|
# Adding a New Package
|
|
|
|
If you want to make artifacts available that do not meet the criteria for
|
|
being included in the "clang" package, you can make package.py upload it to
|
|
a separate zip file and then download it on an opt-in basis by using
|
|
update.py's --package option. Here is [an example of adding a new package].
|
|
|
|
To test changes to `package.py`, change `CLANG_SUB_REVISION` in `update.py` to
|
|
a random number above 2000 and run the `*_upload_clang` trybots.
|
|
|
|
Once the change to `package.py` is in, file a bug under `Tools > LLVM`
|
|
requesting that a new package be created ([example bug]).
|
|
|
|
Once it's been uploaded and rolled, you can download it via:
|
|
|
|
```
|
|
tools/clang/scripts/update.py --package your-package-name
|
|
```
|
|
|
|
[an example of adding a new package](https://chromium-review.googlesource.com/c/chromium/src/+/5463029)
|
|
[example bug]: https://crbug.com/335730441
|