diff -r 13588c901957 -r 9cf78a70fa4f src/hotspot/share/gc/shared/memAllocator.cpp
--- a/src/hotspot/share/gc/shared/memAllocator.cpp	Thu Oct 17 20:27:44 2019 +0100
+++ b/src/hotspot/share/gc/shared/memAllocator.cpp	Thu Oct 17 20:53:35 2019 +0100
@@ -143,7 +143,6 @@
   // Clear unhandled oops for memory allocation.  Memory allocation might
   // not take out a lock if from tlab, so clear here.
   Thread* THREAD = _thread;
-  CHECK_UNHANDLED_OOPS_ONLY(THREAD->clear_unhandled_oops();)
   assert(!HAS_PENDING_EXCEPTION, "Should not allocate with exception pending");
   debug_only(check_for_valid_allocation_state());
   assert(!Universe::heap()->is_gc_active(), "Allocation during gc not allowed");
@@ -172,14 +171,8 @@
   // This is a VM policy failure, so how do we exhaustively test it?
   assert(!_thread->has_pending_exception(),
          "shouldn't be allocating with pending exception");
-  if (StrictSafepointChecks) {
-    assert(_thread->allow_allocation(),
-           "Allocation done by thread for which allocation is blocked "
-           "by No_Allocation_Verifier!");
-    // Allocation of an oop can always invoke a safepoint,
-    // hence, the true argument
-    _thread->check_for_valid_safepoint_state(true);
-  }
+  // Allocation of an oop can always invoke a safepoint.
+  _thread->check_for_valid_safepoint_state();
 }
 #endif
 
@@ -232,10 +225,10 @@
   size_t size_in_bytes = _allocator._word_size * HeapWordSize;
 
   if (_allocated_outside_tlab) {
-    AllocTracer::send_allocation_outside_tlab(_allocator._klass, mem, size_in_bytes, _thread);
+    AllocTracer::send_allocation_outside_tlab(obj()->klass(), mem, size_in_bytes, _thread);
   } else if (_allocated_tlab_size != 0) {
     // TLAB was refilled
-    AllocTracer::send_allocation_in_new_tlab(_allocator._klass, mem, _allocated_tlab_size * HeapWordSize,
+    AllocTracer::send_allocation_in_new_tlab(obj()->klass(), mem, _allocated_tlab_size * HeapWordSize,
                                              size_in_bytes, _thread);
   }
 }
@@ -243,7 +236,7 @@
 void MemAllocator::Allocation::notify_allocation_dtrace_sampler() {
   if (DTraceAllocProbes) {
     // support for Dtrace object alloc event (no-op most of the time)
-    Klass* klass = _allocator._klass;
+    Klass* klass = obj()->klass();
     size_t word_size = _allocator._word_size;
     if (klass != NULL && klass->name() != NULL) {
       SharedRuntime::dtrace_object_alloc(obj(), (int)word_size);
@@ -370,6 +363,10 @@
     HeapWord* mem = mem_allocate(allocation);
     if (mem != NULL) {
       obj = initialize(mem);
+    } else {
+      // The unhandled oop detector will poison local variable obj,
+      // so reset it to NULL if mem is NULL.
+      obj = NULL;
     }
   }
   return obj;
@@ -389,7 +386,7 @@
     oopDesc::set_mark_raw(mem, _klass->prototype_header());
   } else {
     // May be bootstrapping
-    oopDesc::set_mark_raw(mem, markOopDesc::prototype());
+    oopDesc::set_mark_raw(mem, markWord::prototype());
   }
   // Need a release store to ensure array/class length, mark word, and
   // object zeroing are visible before setting the klass non-NULL, for