[not for landing] Debugging gpu failures

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/base/sys-info.h"
 #include "src/code-stubs.h"
@@ skipping 629 matching lines @@
 
   for (Page* p : *space) {
     if (p->NeverEvacuate()) continue;
     // Invariant: Evacuation candidates are just created when marking is
     // started. This means that sweeping has finished. Furthermore, at the end
     // of a GC all evacuation candidates are cleared and their slot buffers are
     // released.
     CHECK(!p->IsEvacuationCandidate());
     CHECK_NULL(p->old_to_old_slots());
     CHECK_NULL(p->typed_old_to_old_slots());
+    if (!p->SweepingDone()) {
+      CHECK(!sweeping_in_progress());
+      CHECK(sweeper().IsSweepingCompleted(space->identity()));
+      CHECK(false);
+    }
     CHECK(p->SweepingDone());
     DCHECK(p->area_size() == area_size);
     pages.push_back(std::make_pair(p->LiveBytesFromFreeList(), p));
   }
 
   int candidate_count = 0;
   size_t total_live_bytes = 0;
 
   const bool reduce_memory = heap()->ShouldReduceMemory();
   if (FLAG_manual_evacuation_candidates_selection) {
@@ skipping 3266 matching lines @@
       // The target is always in old space, we don't have to record the slot in
       // the old-to-new remembered set.
       DCHECK(!heap()->InNewSpace(target));
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8