RFR: 8316746: Top of lock-stack does not match the unlocked object [v3]

[Martin Doerr]

> I think we need to support "Top of lock-stack does not match the unlocked object" and take the slow path. Reason: see JBS issue.
> Currently only PPC64, x86_64 and aarch64 code. I'd like to get feedback before implementing it for other platforms (needed for all platforms).

Martin Doerr has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Pass may_be_unordered information to lightweight_unlock.
 - Merge remote-tracking branch 'origin' into 8316746_lock_stack
 - Add x86_64 and aarch64 implementation.
 - 8316746: Top of lock-stack does not match the unlocked object

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/15903/files
  - new: https://git.openjdk.org/jdk/pull/15903/files/83da590b..2ad32839

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15903&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15903&range=01-02

  Stats: 5179 lines in 187 files changed: 4147 ins; 536 del; 496 mod
  Patch: https://git.openjdk.org/jdk/pull/15903.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15903/head:pull/15903

PR: https://git.openjdk.org/jdk/pull/15903