On Thu, 29 Aug 2024 09:28:50 GMT, Stefan Karlsson <stef...@openjdk.org> wrote:
>> Roman Kennke has updated the pull request incrementally with one additional >> commit since the last revision: >> >> Fix bit counts in GCForwarding > > src/hotspot/share/cds/archiveHeapWriter.cpp line 214: > >> 212: oopDesc::set_mark(mem, markWord::prototype()); >> 213: oopDesc::release_set_klass(mem, k); >> 214: } > > The `UseCompactObjectHeaders` path calls `get_requested_narrow_klass`, while > the `else` part directly uses `k`. Is one of these paths incorrect? This seems odd. The original code sets `Universe::objectArrayKlass()` into the object header. This is the value of this class in the current JVM lifetime. Later, `ArchiveHeapWriter::update_header_for_requested_obj()` would change the object's klass to the "requested" address. I.e., where this class will be loaded in a future JVM lifetime when the CDS archive is loaded into memory. It seems the same logic should be used in the `UseCompactObjectHeaders==true` case. BTW (unrelated to this PR) the comment a few lines up is outdated and wrong: Klass* k = Universe::objectArrayKlass(); // already relocated to point to archived klass `k` is the value of the *actual* location of this class in the current JVM lifetime. Please ignore this comment when trying to understand this function. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20677#discussion_r1737294872
