tree 4f722abe30f3002b9c8ab0113c497fd135e8692d
parent c261b6574af5d5d4ba5fdc370b12e0dcd2c40f9a
author Martin Kustermann <kustermann@google.com> 1626288282 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1626288282 +0000

[vm] Fix racy initialization of lazily populated ObjectStore members

If two threads concurrently trigger initialization of the lazily
populated ObjectStore members, they have to coordinate.

We ensure mutual exclusion by holding a writer lock, to ensure only one
thread can perform the lazy initialization. Furthermore we use
store-release/load-acquire for those ObjectStore fields to ensure that
once an object is made available on ObjectStore all of it's initializing
stores are visible at that point.

We no longer make public setters for those fields, since they shouldn't
be used (only the getters + lazy initialization should be used)

Fixes https://github.com/dart-lang/sdk/issues/46611

TEST=Fixes TSAN races reported on iso-stres builder.

Change-Id: Icaf54bb224e74baf1bfbb4a9bfc386ebfbd52755
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206782
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>