Refactor snapshots pieces to include a section for loading instructions into the heap of a regular …

runtime/vm/pages.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_PAGES_H_
 #define RUNTIME_VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/lockers.h"
@@ skipping 10 matching lines @@
 
 // Forward declarations.
 class Heap;
 class JSONObject;
 class ObjectPointerVisitor;
 class ObjectSet;
 
 // A page containing old generation objects.
 class HeapPage {
  public:
-  enum PageType { kData = 0, kExecutable, kReadOnlyData, kNumPageTypes };
+  enum PageType { kData = 0, kExecutable, kNumPageTypes };

[siva, 2017/01/20 22:53:54]

See note in other file about page types.

 
   HeapPage* next() const { return next_; }
   void set_next(HeapPage* next) { next_ = next; }
 
   bool Contains(uword addr) { return memory_->Contains(addr); }
 
   uword object_start() const { return memory_->start() + ObjectStartOffset(); }
   uword object_end() const { return object_end_; }
 
   PageType type() const { return type_; }
@@ skipping 182 matching lines @@
     MutexLocker ml(pages_lock_);
     return usage_;
   }
 
   bool Contains(uword addr) const;
   bool Contains(uword addr, HeapPage::PageType type) const;
   bool DataContains(uword addr) const;
   bool IsValidAddress(uword addr) const { return Contains(addr); }
 
   void VisitObjects(ObjectVisitor* visitor) const;
-  void VisitObjectsNoEmbedderPages(ObjectVisitor* visitor) const;
+  void VisitObjectsNoExternalPages(ObjectVisitor* visitor) const;
+  void VisitObjectsExternalPages(ObjectVisitor* visitor) const;

[siva, 2017/01/20 22:53:54]

The external page name here is confusing with the external size
we use for tracking the space allocated by embedder which is associated with
weak handles.

   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
   RawObject* FindObject(FindObjectVisitor* visitor,
                         HeapPage::PageType type) const;
 
   // Checks if enough time has elapsed since the last attempt to collect
   // code.
   bool ShouldCollectCode();
 
   // Collect the garbage in the page space using mark-sweep.
@@ skipping 179 matching lines @@
   friend class HeapIterationScope;
   friend class PageSpaceController;
   friend class SweeperTask;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_PAGES_H_