tree def3903a37938849b2aa1e7885808bf4b6cc1645
parent 83e460ab6ddf68874a39ffe9fbb6ebcaaeeaf7e0
author Martin Kustermann <kustermann@google.com> 1606920767 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1606920767 +0000

[vm/concurrency] Make updates to MegamorphicCache use type_feedback_mutex to prevent concurrent access

With lightweights isolates enabled we need to ensure to update entries
in MetamorphicCache in sequence with mutual exclusion.

This CL adds appropriate locking for the MegamorphicCache.

Right now this is safe in AOT because the entire SwitchableCallMiss
handler runs with stopped mutators. A future CL will relax this. That
future CL will also move the megamorphic mutex from Isolate to
IsolateGroup, since the megamoprhic caches are shared within an isolate
group.

Issue https://github.com/dart-lang/sdk/issues/36097

TEST=CL is purely a refactoring.

Change-Id: I30305b04027d2bf9b4d5f6b1700bf158d38bdba7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/174467
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>