Lazy peer API.

runtime/vm/pages.h

Index: runtime/vm/pages.h
diff --git a/runtime/vm/pages.h b/runtime/vm/pages.h
index 83a07ddc0ffc45f2d10652dddbb95a43ce948474..948e464fac62c9d10936f726f922a40a47f5cb14 100644
--- a/runtime/vm/pages.h
+++ b/runtime/vm/pages.h
@@ -5,6 +5,8 @@
 #ifndef VM_PAGES_H_
 #define VM_PAGES_H_
 
+#include <map>
+
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
@@ -59,6 +61,8 @@ class HeapPage {
 
   void WriteProtect(bool read_only);
 
+  void SetPeer(RawObject* raw_obj, void* peer);
+
  private:
   static HeapPage* Initialize(VirtualMemory* memory, bool is_executable);
   static HeapPage* Allocate(intptr_t size, bool is_executable);
@@ -201,6 +205,12 @@ class PageSpace {
 
   void WriteProtect(bool read_only);
 
+  void SetPeer(RawObject* raw_obj, void* peer);
+
+  void* GetPeer(RawObject* raw_obj);
+
+  int64_t PeerCount() const;
+
  private:
   static const intptr_t kAllocatablePageSize = kPageSize - sizeof(HeapPage);
 
@@ -227,6 +237,8 @@ class PageSpace {
   HeapPage* pages_tail_;
   HeapPage* large_pages_;
 
+  std::map<RawObject*, void*> peer_;

[siva, 2012/09/14 00:03:46]

Call this peer_table_ or peer_map_;

[cshapiro, 2012/09/15 01:23:41]

Done.

+
   // Page being used for bump allocation.
   // The value has different meanings:
   // NULL: Still bump allocating from last allocated fresh page.