[heap] Simulate aborting compaction during --stress-compaction

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 1623 matching lines @@
   EvacuateVisitorBase(Heap* heap, CompactionSpaceCollection* compaction_spaces)
       : heap_(heap),
         compaction_spaces_(compaction_spaces),
         profiling_(
             heap->isolate()->cpu_profiler()->is_profiling() ||
             heap->isolate()->logger()->is_logging_code_events() ||
             heap->isolate()->heap_profiler()->is_tracking_object_moves()) {}
 
   inline bool TryEvacuateObject(PagedSpace* target_space, HeapObject* object,
                                 HeapObject** target_object) {
+#ifdef VERIFY_HEAP

[Hannes Payer (out of office), 2016/05/31 14:01:04]

Can we move that code into a SimulateCompactionAbortion function which is only
called in VERIFY_HEAP? That keeps the main function small.

[Michael Lippautz, 2016/05/31 14:08:58]

Done.

+    if (FLAG_stress_compaction) {
+      // Simulate aborting compaction.
+      const uintptr_t mask = static_cast<uintptr_t>(FLAG_random_seed) &
+                             Page::kPageAlignmentMask & ~kPointerAlignmentMask;
+      if ((reinterpret_cast<uintptr_t>(object->address()) &
+           Page::kPageAlignmentMask) == mask) {
+        Page* page = Page::FromAddress(object->address());
+        if (page->IsFlagSet(Page::COMPACTION_WAS_ABORTED_FOR_TESTING)) {
+          page->ClearFlag(Page::COMPACTION_WAS_ABORTED_FOR_TESTING);
+        } else {
+          page->SetFlag(Page::COMPACTION_WAS_ABORTED_FOR_TESTING);
+          return false;
+        }
+      }
+    }
+#endif  // VERIFY_HEAP
     int size = object->Size();
     AllocationAlignment alignment = object->RequiredAlignment();
     AllocationResult allocation = target_space->AllocateRaw(size, alignment);
     if (allocation.To(target_object)) {
       MigrateObject(*target_object, object, size, target_space->identity());
       return true;
     }
     return false;
   }
 
@@ skipping 2287 matching lines @@
     MarkBit mark_bit = Marking::MarkBitFrom(host);
     if (Marking::IsBlack(mark_bit)) {
       RelocInfo rinfo(isolate(), pc, RelocInfo::CODE_TARGET, 0, host);
       RecordRelocSlot(host, &rinfo, target);
     }
   }
 }
 
 }  // namespace internal
 }  // namespace v8