[heap] Evacuation for young generation

test/unittests/heap/spaces-unittest.cc

 // Copyright 2017 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/heap-inl.h"
 #include "src/heap/spaces-inl.h"
 #include "src/isolate.h"
 #include "test/unittests/test-utils.h"
 
 namespace v8 {
 namespace internal {
 
 typedef TestWithIsolate SpacesTest;
 
 TEST_F(SpacesTest, CompactionSpaceMerge) {
   Heap* heap = i_isolate()->heap();
   OldSpace* old_space = heap->old_space();
   EXPECT_TRUE(old_space != NULL);
 
   CompactionSpace* compaction_space =
       new CompactionSpace(heap, OLD_SPACE, NOT_EXECUTABLE);
   EXPECT_TRUE(compaction_space != NULL);
   EXPECT_TRUE(compaction_space->SetUp());
 
+  for (Page* p : *old_space) {
+    // Unlink free lists from the main space to avoid reusing the memory for
+    // compaction spaces.
+    old_space->UnlinkFreeListCategories(p);
+  }
+
   // Cannot loop until "Available()" since we initially have 0 bytes available
   // and would thus neither grow, nor be able to allocate an object.
   const int kNumObjects = 10;
   const int kNumObjectsPerPage =
       compaction_space->AreaSize() / kMaxRegularHeapObjectSize;
   const int kExpectedPages =
       (kNumObjects + kNumObjectsPerPage - 1) / kNumObjectsPerPage;
   for (int i = 0; i < kNumObjects; i++) {
     HeapObject* object =
         compaction_space->AllocateRawUnaligned(kMaxRegularHeapObjectSize)
             .ToObjectChecked();
     heap->CreateFillerObjectAt(object->address(), kMaxRegularHeapObjectSize,
                                ClearRecordedSlots::kNo);
   }
   int pages_in_old_space = old_space->CountTotalPages();
   int pages_in_compaction_space = compaction_space->CountTotalPages();
   EXPECT_EQ(kExpectedPages, pages_in_compaction_space);
   old_space->MergeCompactionSpace(compaction_space);
   EXPECT_EQ(pages_in_old_space + pages_in_compaction_space,
             old_space->CountTotalPages());
 
   delete compaction_space;
 }
 
 }  // namespace internal
 }  // namespace v8