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

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 0981c3650efe8d9b6fa6b55ac4e8b06de811e6b5..7bb243a2120abc6c4d70ca9693ca44301ddfcad3 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -425,6 +425,10 @@ class MemoryChunk {
     // from new to old space during evacuation.
     PAGE_NEW_OLD_PROMOTION,
 
+    // |PAGE_NEW_NEW_PROMITION|: A page tagged with this flag has been moved

[ulan, 2016/06/14 15:38:51]

typo PAGE_NEW_NEW_PROMOTION

[Michael Lippautz, 2016/06/15 06:49:30]

Done.

+    // within the new space during evacuation.
+    PAGE_NEW_NEW_PROMOTION,
+
     // A black page has all mark bits set to 1 (black). A black page currently
     // cannot be iterated because it is not swept. Moreover live bytes are also
     // not updated.
@@ -2440,6 +2444,8 @@ class SemiSpace : public Space {
   Page* first_page() { return anchor_.next_page(); }
   Page* current_page() { return current_page_; }
 
+  bool OnLastPage() { return current_page() == anchor()->prev_page(); }
+
   // Returns one past the end address of the space.
   Address space_end() { return anchor_.prev_page()->area_end(); }
 
@@ -2535,8 +2541,9 @@ class SemiSpace : public Space {
   Page anchor_;
   Page* current_page_;
 
-  friend class SemiSpaceIterator;
+  friend class NewSpace;
   friend class NewSpacePageIterator;
+  friend class SemiSpaceIterator;
 };
 
 
@@ -2721,6 +2728,16 @@ class NewSpace : public Space {
     return from_space_.ReplaceWithEmptyPage(page);
   }
 
+  // Swaps the given |from_space_page| with a proper page in *to* space. The
+  // method should only be called during evacuation.
+  void SwapFromSpacePageWithToSpacePage(Page* from_space_page);
+
+  // Swaps |from_space_page| with |to_space_page| by swapping their interiors
+  // and inserting them at |from_target| and |to_target| respectively. Note
+  // that this implies that |from_target| is in *to* space and vice versa.
+  void SwapPages(Page* from_space_page, Page* to_space_page, Page* from_target,
+                 Page* to_target);
+
   // Return the maximum capacity of a semispace.
   int MaximumCapacity() {
     DCHECK(to_space_.maximum_capacity() == from_space_.maximum_capacity());