On Tue, 16 Jun 2026 12:14:41 GMT, David Simms <[email protected]> wrote:
>> This is a "*sub-review pull request*" for the first >> [preview](https://openjdk.org/jeps/12) of [JEP 401: Value Classes and >> Objects](https://openjdk.org/jeps/401), specifically >> [JDK-8317278](https://bugs.openjdk.org/browse/JDK-8317278): JVM >> implementation of value classes and objects. >> >>> [!NOTE] >>> This pull request and the other sub-review pull requests listed below are >>> based on the "*master pull request*" >>> (https://github.com/openjdk/jdk/pull/31120). It contains the same full set >>> of code changes as the "*master pull request*" to preserve the full >>> implementation context; the language compiler, JVM, and standard library >>> changes are intertwined. This separate pull requests exist only to >>> subdivide the review and related discussion by area. >> >> Other areas for review: >> >> - [JDK-8317277](https://bugs.openjdk.org/browse/JDK-8317277): Java language >> implementation of value classes and objects >> - https://github.com/openjdk/jdk/pull/31121 >> - [JDK-8317279](https://bugs.openjdk.org/browse/JDK-8317279): Standard >> library implementation of value classes and objects >> - https://github.com/openjdk/jdk/pull/31123 >> >> Code changes resulting from the review process should be made in >> [`valhalla/lworld`](https://github.com/openjdk/valhalla/). >> >> `valhalla/lworld` is currently updated from `jdk/master` whenever a weekly >> [`jdk` tag](https://github.com/openjdk/jdk/tags) is created. At that time, >> code changes from `valhalla/lworld` will be propagated to the master pull >> request and to all sub-review pull requests, including this one. >> >> Ultimately, review sign-off will be recorded on the "*master pull request*", >> and this pull request will be closed without integration. >> >> This pull request has a large code surface area and often conflicts with >> `jdk/master` on a daily basis. Refer to >> [`valhalla/lworld`](https://github.com/openjdk/valhalla/) for the latest >> state of the project code, keeping in mind that it may lag several days >> behind `jdk/master`. Both repositories may be needed as references during >> review. >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > David Simms has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 2822 commits: > > - Merge branch '8317277' into jep401_sub_review_8317278 > - Merge remote-tracking branch 'valhalla/lworld' into 8317277 > - 8386690: [lworld] cherry-pick JDK-8386124 Test > serviceability/sa/TestG1HeapRegion.java failed: Address of G1HeapRegion does > not match > > Reviewed-by: liach > - 8385743: [lworld] investigate and address build related comments in the > Valhalla PR > > Reviewed-by: liach, erikj > - 8376346: [lworld] Basic Shenandoah support > > Reviewed-by: qamai > - 8386598: [lworld] C1 acmp profiling fix and minor cleanup > > Reviewed-by: mchevalier > - 8386618: [lworld] Remove unused entry_guard_Relocation > > Reviewed-by: chagedorn, jsjolen, jsikstro > - Merge > > Merge jdk-28+2 > - 8386623: [lworld] Cleanup module support for system modules in JDK > exploded build with preview resources > > Reviewed-by: liach > - 8386316: [lworld] Replace Valhalla since version with 28 > > Reviewed-by: darcy > - ... and 2812 more: https://git.openjdk.org/jdk/compare/6def7d55...c2d3cf01 src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp line 286: > 284: LIR_Opr lock = new_register(T_INT); > 285: // Need a scratch register for inline types on x86 > 286: LIR_Opr scratch = new_register(T_ADDRESS); Suggestion: A temp register is always needed now, so let's keep the mainline version. src/hotspot/cpu/x86/c1_LIRGenerator_x86.cpp line 302: > 300: CodeEmitInfo* info = state_for(x, x->state(), true); > 301: monitor_enter(obj.result(), lock, syncTempOpr(), scratch, > 302: x->monitor_no(), info_for_exception, info, > throw_ie_stub); Suggestion: LIR_Opr tmp = new_register(T_ADDRESS); monitor_enter(obj.result(), lock, syncTempOpr(), tmp, x->monitor_no(), info_for_exception, info); ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/31122#discussion_r3438837024 PR Review Comment: https://git.openjdk.org/jdk/pull/31122#discussion_r3438840971
