On Thu, 12 Mar 2026 16:20:08 GMT, Roman Kennke <[email protected]> wrote:
>> Thomas Stuefe has updated the pull request with a new target base due to a >> merge or a rebase. The pull request now contains 65 commits: >> >> - Merge branch 'master' into JDK-8363996-Obsolete-UseCompressedClassPointers >> - Replace Metaspace::using_class_space with define >> - Update src/hotspot/cpu/x86/macroAssembler_x86.hpp >> >> Co-authored-by: David Holmes >> <[email protected]> >> - Replace Klass::_metadata union with narrowKlass member >> - Ivan: fix various instances of ObjLayout::undefined should assert >> - Ivan: Update src/hotspot/share/oops/instanceKlass.cpp >> >> Co-authored-by: Ivan Walulya <[email protected]> >> - David: reduce diff in ObjectCountEventVerifier.java >> - David: minimize change in GetObjectSizeIntrinsicsTest.java >> - David: minimize diffs in TestZGCWithCDS.java >> - David: minimize diffs for >> runtime/ErrorHandling/TestVMConfigInHsErrFile.java >> - ... and 55 more: https://git.openjdk.org/jdk/compare/9a26b4af...be3a902b > > src/hotspot/share/oops/objLayout.hpp line 29: > >> 27: >> 28: /* >> 29: * This class helps to avoid loading more than one flag in some > > This whole class might not be needed anymore. The purpose of the class was to > be able to avoid chains of loads of different flags like: > > if (UseCompactObjectHeaders) { > } else if (UseCompressedClassPointers) { > } else { > } > > And replace it with a single load and switch. This made a perf difference in > some critical paths. Now, with UCCP gone, those cases can simply be handled > as if (UCOH) {..} else {..} again. > > Maybe handle it in a follow-up issue. I kept it in case we want to merge Lilliput 2 into mainline. Then, we would have to deal with these chains again. > src/hotspot/share/runtime/os.cpp line 1342: > >> 1340: >> 1341: // Compressed klass needs to be decoded first. >> 1342: // Todo: questionable for COH - can we do this better? > > Is it worth tracking in a JBS issue? Yes. In fact, with COH, we could make os::print_location spot markwords now with some reliability, since the KP is part of the MW and it must be valid. https://bugs.openjdk.org/browse/JDK-8380425 ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/28366#discussion_r2958426902 PR Review Comment: https://git.openjdk.org/jdk/pull/28366#discussion_r2958421210
