[GR-71401] Verify that objects in the young generation don't have a remembered set bit.

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/FillerObjectUtil.java

@@ -65,13 +65,13 @@ static int arrayBaseOffset() {
     }
 
     @Uninterruptible(reason = CALLED_FROM_UNINTERRUPTIBLE_CODE, mayBeInlined = true)
-    public static void writeFillerObjectAt(Pointer p, UnsignedWord size) {
+    public static void writeFillerObjectAt(Pointer p, UnsignedWord size, boolean rememberedSet) {
         assert size.aboveThan(0);
         if (size.aboveOrEqual(arrayMinSize())) {
             int length = UnsignedUtils.safeToInt(size.subtract(arrayBaseOffset()).unsignedDivide(ARRAY_ELEMENT_SIZE));
-            FormatArrayNode.formatArray(p, ARRAY_CLASS, length, true, false, WITH_GARBAGE_IF_ASSERTIONS_ENABLED, false);
+            FormatArrayNode.formatArray(p, ARRAY_CLASS, length, rememberedSet, false, WITH_GARBAGE_IF_ASSERTIONS_ENABLED, false);
         } else {
-            FormatObjectNode.formatObject(p, FillerObject.class, true, WITH_GARBAGE_IF_ASSERTIONS_ENABLED, false);
+            FormatObjectNode.formatObject(p, FillerObject.class, rememberedSet, WITH_GARBAGE_IF_ASSERTIONS_ENABLED, false);
         }
         assert LayoutEncoding.getSizeFromObjectInGC(p.toObject()).equal(size);
     }

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/HeapVerifier.java

@@ -323,6 +323,11 @@ private static boolean verifyObject(Object obj, AlignedHeader aChunk, UnalignedH
                 Log.log().string("Object ").zhex(ptr).string(" is in ").string(space.getName()).string(" chunk ").zhex(chunk).string(" but does not have a remembered set.").newline();
                 return false;
             }
+        } else if (space.isYoungSpace()) {
+            if (SerialGCOptions.useRememberedSet() && RememberedSet.get().hasRememberedSet(header)) {
+                Log.log().string("Object ").zhex(ptr).string(" is in ").string(space.getName()).string(" chunk ").zhex(chunk).string(" but has a remembered set.").newline();
+                return false;
+            }
         }
 
         return verifyReferences(obj);

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/TlabSupport.java

@@ -363,7 +363,7 @@ private static void insertFiller(ThreadLocalAllocation.Descriptor tlab) {
         UnsignedWord size = hardEnd.subtract(top);
 
         if (top.belowThan(hardEnd)) {
-            FillerObjectUtil.writeFillerObjectAt(top, size);
+            FillerObjectUtil.writeFillerObjectAt(top, size, false);
         }
     }
 

substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/compacting/SweepingVisitor.java

@@ -43,7 +43,7 @@ public boolean visit(Pointer objSeq, UnsignedWord size, Pointer newAddress, Poin
         if (nextObjSeq.isNonNull()) {
             Pointer gapStart = objSeq.add(size);
             assert gapStart.belowThan(nextObjSeq);
-            FillerObjectUtil.writeFillerObjectAt(gapStart, nextObjSeq.subtract(gapStart));
+            FillerObjectUtil.writeFillerObjectAt(gapStart, nextObjSeq.subtract(gapStart), true);
             // Note that we have already added first object table entries for fillers during fixup.
         } else {
             AlignedHeapChunk.AlignedHeader chunk = AlignedHeapChunk.getEnclosingChunkFromObjectPointer(objSeq);