On Wed, 8 Jul 2026 07:13:02 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 incrementally with 11 additional > commits since the last revision: > > - Merge branch '8317277' into jep401_sub_review_8317278 > - Merge remote-tracking branch 'valhalla/lworld' into 8317277 > - 8387703: [lworld] address batch of comments in mainline PR > > Co-authored-by: Tobias Hartmann <[email protected]> > Reviewed-by: thartmann, dlong > - 8387661: [lworld] move generate_return_value_stub() to SharedRuntime > > Reviewed-by: adinn, thartmann > - 8387405: [lworld] is_always_flat_in_array should be always false > > Reviewed-by: thartmann > - 8387686: [lworld] Update the JNI specification version for value types > > Reviewed-by: alanb, dsimms > - 8387726: [lworld] JVMTI/JDWP/JDI docs cleanup > > Reviewed-by: sspitsyn, cjplummer > - 8387673: [lworld] C2: clone() intrinsic does not throw > CloneNotSupportedException for value classes not implementing Cloneable > > Reviewed-by: thartmann > - 8387709: [lworld] Split Valhalla tests from tier1_compiler_3 to avoid task > timeouts > > Reviewed-by: chagedorn > - 8387350: [lworld] ObjectOutputStream.writeObject() doesn't throw > InvalidClassException for Serializable instance with strict init fields > > Reviewed-by: alanb, jpai, thartmann > - ... and 1 more: https://git.openjdk.org/jdk/compare/f1f6d35d...1b6f7c18 src/hotspot/share/opto/matcher.cpp line 1096: > 1094: mask = return_values_mask(n->in(0)->as_Call()->tf()); > 1095: } > 1096: m = n->in(0)->as_Multi()->match(n->as_Proj(), this, > mask); "mask" is only used by CallNode::match(). Let's move the call to return_values_mask() there so we don't have to compute a mask that will be ignored by other match() virtual functions. src/hotspot/share/opto/mulnode.hpp line 220: > 218: virtual const Type* bottom_type() const { return TypeTuple::LONG_PAIR; > } > 219: > 220: virtual Node* match(const ProjNode* proj, const Matcher* m, const > RegMask* mask); Let's revert the addition of "mask" and compute it only where needed. See comments in matcher.cpp and callnode.cpp. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/31122#discussion_r3575945750 PR Review Comment: https://git.openjdk.org/jdk/pull/31122#discussion_r3575949996
