BASELINE: Update Chromium to 85.0.4183.14085-based

Change-Id: Iaa42f4680837c57725b1344f108c0196741f6057
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 27 insertions, 40 deletions

diff --git a/chromium/docs/updating_clang.md b/chromium/docs/updating_clang.md
index 9210b5426ec..72fe848b9ce 100644
--- a/chromium/docs/updating_clang.md
+++ b/chromium/docs/updating_clang.md
@@ -9,50 +9,37 @@ 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.
 1.  Sync your Chromium tree to the latest revision to pick up any plugin
-    changes
-1.  Run `python tools/clang/scripts/upload_revision.py NNNN`
-    with the target LLVM SVN revision number. This creates a roll CL on a new
-    branch, uploads it and starts tryjobs that build the compiler binaries into
-    a staging bucket on Google Cloud Storage (GCS).
-1.  If the clang upload try bots succeed, copy the binaries from the staging
-    bucket to the production one. For example:
+    changes.
+1.  Run go/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 goma. If you do not have the necessary credentials to do the upload, ask
+    clang@chromium.org to find someone who does.
+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 goma will have a matching
+    binary, too.
 
-    ```shell
-    $ export rev=n123456-abcd1234-1
-    $ for x in Linux_x64 Mac Win ; do \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-$rev.tgz \
-            gs://chromium-browser-clang/$x/clang-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-$rev-buildlog.txt \
-            gs://chromium-browser-clang/$x/clang-$rev-buildlog.txt ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-tidy-$rev.tgz \
-            gs://chromium-browser-clang/$x/clang-tidy-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/llvmobjdump-$rev.tgz \
-            gs://chromium-browser-clang/$x/llvmobjdump-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/translation_unit-$rev.tgz \
-            gs://chromium-browser-clang/$x/translation_unit-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/llvm-code-coverage-$rev.tgz \
-            gs://chromium-browser-clang/$x/llvm-code-coverage-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/libclang-$rev.tgz \
-            gs://chromium-browser-clang/$x/libclang-$rev.tgz ; \
-        done && gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/Mac/lld-$rev.tgz \
-            gs://chromium-browser-clang/Mac/lld-$rev.tgz
-    ```
+## Performance regressions
 
-    **Note** that 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).
+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.
 
-1.  Run the goma package update script to push these packages to goma. If you do
-    not have the necessary credentials to do the upload, ask clang@chromium.org
-    to find someone who does
-1.  Run an exhaustive set of try jobs to test the new compiler. The CL
-    description created 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).
+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.
 
-1.  Commit roll CL from the first step
-1.  The bots will now pull the prebuilt binary, and goma will have a matching
-    binary, too.
+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