🏄 [heap] Add page evacuation mode for new->old

src/heap/heap.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 1383 matching lines @@
 
  private:
   class PretenuringScope;
   class UnmapFreeMemoryTask;
 
   // External strings table is a place where all external strings are
   // registered.  We need to keep track of such strings to properly
   // finalize them.
   class ExternalStringTable {
    public:
+    enum CleanupMode { kFull, kPromoteOnly };
+
     // Registers an external string.
     inline void AddString(String* string);
 
     inline void Iterate(ObjectVisitor* v);
 
     // Restores internal invariant and gets rid of collected strings.
     // Must be called after each Iterate() that modified the strings.
+    template <CleanupMode mode = kFull>
     void CleanUp();
 
     // Destroys all allocated memory.
     void TearDown();
 
    private:
     explicit ExternalStringTable(Heap* heap) : heap_(heap) {}
 
     inline void Verify();
 
@@ skipping 1232 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_