On Fri, 29 Apr 2022 22:50:45 GMT, Ioi Lam <ik...@openjdk.org> wrote: > During `java -Xshare:dump -XX:-UseCompressedOops`, the location of the Java > heap is chosen by the OS. Due to Address Space Layout Randomization, the heap > will always start at a different location. This causes the archive for > uncompressed oops ($JAVA_HOME/lib/server/classes_nocoops.jsa) to be > non-deterministic. > > The fix is to patch the archived object pointers to make it look like the > heap starts at a fixed address -- I chose 0x10000000, but the exact value > doesn't really matter. > > At runtime, the object pointers will be patched again according to the real > location of the heap. > > Tested with tiers 1-5. I am running builds-tier5 several times to test the > xxx-cmp-baseline builds.
src/hotspot/share/cds/heapShared.cpp line 184: > 182: // Do not call p->identity_hash() as that will update the > 183: // object header. > 184: return primitive_hash(cast_from_oop<intptr_t>(p)); This fix doesn't affect the contents of the archive, but it's necessary to avoid incorrect output from `-Xlog:cds+map=trace`. ------------- PR: https://git.openjdk.java.net/jdk/pull/8478
