[jdk25u-dev] RFR: 8358735: GenShen: block_start() may be incorrect after class unloading [v2]

[Rui Li]

> Backport of JDK-8358735 and its two follow up fixes: JDK-8372110 and JDK-8371854.
> 
> The backport of the original issue (JDK-8358735) is almost clean except that atomic.hpp was renamed to atomicAccess.hpp in the later versions, and I had to resolve the conflict by retaining atomic.hpp import.
> 
> The two follow up backports are clean.
> 
> Our internal application crashed and we identified JDK-8358735 was the root cause. Backporting it for the fix.
> 
> Testing: pending.

Rui Li has updated the pull request incrementally with two additional commits since the last revision:

 - 8371854: Shenandoah: Simplify WALK_FORWARD_IN_BLOCK_START use
   
   Backport 713de231a61234632e2f9858b222b5f7fd0bdaf1
 - 8372110: GenShen: Fix erroneous assert
   
   Backport aa7718d1d2008c240c197383c493955d8b654bf3

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

Changes:
  - all: https://git.openjdk.org/jdk25u-dev/pull/19/files
  - new: https://git.openjdk.org/jdk25u-dev/pull/19/files/ca08e4d2..0fbe598e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=19&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=19&range=00-01

  Stats: 15 lines in 1 file changed: 4 ins; 7 del; 4 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/19.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/19/head:pull/19

PR: https://git.openjdk.org/jdk25u-dev/pull/19