On Mon, 15 Jun 2026 07:20:20 GMT, Matthias Baesken <[email protected]> wrote:
>> When building hotspot on linuxx86_64/gcc with LTO enabled >> (--enable-jvm-feature-link-time-opt), we get various test errors in the >> serviceability/sa area. >> Example serviceability/sa/CDSJMapClstats.java >> >> >> finding class loader instances ..java.lang.InternalError: Metadata does not >> appear to be polymorphic >> at >> jdk.hotspot.agent/sun.jvm.hotspot.types.basic.BasicTypeDataBase.findDynamicTypeForAddress(BasicTypeDataBase.java:223) >> at >> jdk.hotspot.agent/sun.jvm.hotspot.runtime.VirtualBaseConstructor.instantiateWrapperFor(VirtualBaseConstructor.java:104) >> at >> jdk.hotspot.agent/sun.jvm.hotspot.oops.Metadata.instantiateWrapperFor(Metadata.java:77) >> at >> jdk.hotspot.agent/sun.jvm.hotspot.memory.SystemDictionary.getClassLoaderKlass(SystemDictionary.java:102) >> at >> jdk.hotspot.agent/sun.jvm.hotspot.tools.ClassLoaderStats.printClassLoaderStatistics(ClassLoaderStats.java:93) >> at >> jdk.hotspot.agent/sun.jvm.hotspot.tools.ClassLoaderStats.run(ClassLoaderStats.java:78) >> at jdk.hotspot.agent/sun.jvm.hotspot.tools.JMap.run(JMap.java:121) >> at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:278) >> at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.start(Tool.java:241) >> at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.execute(Tool.java:134) >> at jdk.hotspot.agent/sun.jvm.hotspot.tools.JMap.main(JMap.java:202) >> at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runJMAP(SALauncher.java:344) >> at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:507) >> >> >> Seems we have to avoid elimination of the Metadata vtable ; this can be >> achieved by linker flags or by modifying class Metadata. >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Matthias Baesken has updated the pull request incrementally with one > additional commit since the last revision: > > metadata: just add a comment, only rely on the linker setting src/hotspot/share/oops/metadata.hpp line 40: > 38: // for serviceability tests to work. > 39: // This can be done by linker settings or modifications to the Metadata > class. > 40: Sorry I haven't been keeping up with this thread. I believe I ask about PRODUCT builds before. How does all this work with PRODUCT builds since there is no is_valid() method forcing there to be a Metadata vtable? Can you also expand the comment a bit to explain why we need both is_valid() and the linker option? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/30771#discussion_r3415602163
