RFR: 8357258: x86: Improve receiver type profiling reliability [v2]

Aleksey Shipilev shade at openjdk.org
Mon Sep 15 14:27:28 UTC 2025


> See the bug for discussion what issues current machinery has. 
> 
> This PR executes the plan outlined in the bug:
>  1. Common the receiver type profiling code in interpreter and C1
>  2. Rewrite receiver type profiling code to only do atomic receiver slot installations
>  3. Trim `C1OptimizeVirtualCallProfiling` to only claim slots when receiver is installed 
> 
> This PR does _not_ do atomic counter updates themselves, as it may have much wider performance implications, including regressions. This PR should be at least performance neutral.
> 
> Additional testing:
>   - [x] Linux x86_64 server fastdebug, `compiler/`
>   - [ ] Linux x86_64 server fastdebug, `all`

Aleksey Shipilev 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 three additional commits since the last revision:

 - Merge branch 'master' into JDK-8357258-x86-c1-optimize-virt-calls
 - Drop atomic counters
 - Initial version

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25305/files
  - new: https://git.openjdk.org/jdk/pull/25305/files/e078cfb1..f934435b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25305&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25305&range=00-01

  Stats: 29954 lines in 1034 files changed: 14950 ins; 9185 del; 5819 mod
  Patch: https://git.openjdk.org/jdk/pull/25305.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25305/head:pull/25305

PR: https://git.openjdk.org/jdk/pull/25305


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