src/hotspot/share/gc/z/zForwarding.cpp

@@ -19,10 +19,11 @@
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
+ #include "gc/shared/gc_globals.hpp"
  #include "gc/shared/gcLogPrecious.hpp"
  #include "gc/z/zAddress.inline.hpp"
  #include "gc/z/zCollectedHeap.hpp"
  #include "gc/z/zForwarding.inline.hpp"
  #include "gc/z/zPage.inline.hpp"

@@ -370,10 +371,11 @@
    guarantee(_ref_count.load_relaxed() != 0, "Invalid reference count");
    guarantee(_page != nullptr, "Invalid page");
  
    uint32_t live_objects = 0;
    size_t live_bytes = 0;
+   uint32_t no_move_expand_count = 0;
  
    for (ZForwardingCursor i = 0; i < _entries.length(); i++) {
      const ZForwardingEntry entry = at(&i);
      if (!entry.populated()) {
        // Skip empty entries

@@ -393,15 +395,31 @@
  
        guarantee(entry.from_index() != other.from_index(), "Duplicate from");
        guarantee(entry.to_offset() != other.to_offset(), "Duplicate to");
      }
  
+     // Read size from the TO object — always safe after relocation.
      const zaddress to_addr = ZOffset::address(to_zoffset(entry.to_offset()));
      const size_t size = ZUtils::object_size(to_addr);
      const size_t aligned_size = align_up(size, _page->object_alignment());
      live_bytes += aligned_size;
      live_objects++;
+ 
+     // Detect non-moving in-place objects (from_offset == to_offset): they are counted in
+     // will_expand_objects if they had is_hashed_not_expanded() at mark time, but they did not
+     // actually expand during relocation (size = old_size). Track these so verify_live() can
+     // subtract them from the expected live_bytes adjustment.
+     if (_in_place && UseCompactObjectHeaders) {
+       const zoffset from_offset = start() + (entry.from_index() << object_alignment_shift());
+       if (to_zoffset(entry.to_offset()) == from_offset) {
+         const oop to_obj = to_oop(to_addr);
+         if (to_obj->mark().is_hashed_not_expanded() && to_obj->klass()->expand_for_hash(to_obj, to_obj->mark())) {
+           no_move_expand_count++;
+         }
+       }
+     }
    }
  
-   // Verify number of live objects and bytes
-   _page->verify_live(live_objects, live_bytes, _in_place);
+   // Verify number of live objects and bytes. live_bytes is computed from TO-space sizes;
+   // verify_live() adjusts for compact hash expansion using the will_expand and no_move counts.
+   _page->verify_live(live_objects, live_bytes, no_move_expand_count, _in_place);
  }