Track external allocated memory for weak persistent handles.

runtime/vm/dart_api_state.h

Index: runtime/vm/dart_api_state.h
===================================================================
--- runtime/vm/dart_api_state.h	(revision 33235)
+++ runtime/vm/dart_api_state.h	(working copy)
@@ -8,6 +8,7 @@
 #include "include/dart_api.h"
 
 #include "platform/thread.h"
+#include "platform/utils.h"
 #include "vm/dart_api_impl.h"
 #include "vm/flags.h"
 #include "vm/growable_array.h"
@@ -198,6 +199,26 @@
     callback_ = callback;
   }
 
+  void SetExternalAllocationSize(intptr_t size, Heap* heap) {

[Ivan Posva, 2014/03/06 21:59:33]

SetExternalSize() to match the field.

[koda, 2014/03/06 22:55:07]

Done.

+    ASSERT(size >= 0);
+    external_size_ = Utils::RoundUp(size, kObjectAlignment);
+    // TODO(koda): On repeated/large external allocations for existing objects,
+    // without any intervening normal allocation, GC will not trigger.
+    heap->AllocateExternal(external_size_, raw());
+  }
+
+  // Called when the referent becomes unreachable.
+  void UpdateUnreachable(Heap* heap) {
+    heap->FreeExternal(external_size_, raw());
+    Finalize(this);
+  }
+
+  // Called when the referent has moved, potentially between generations.
+  void UpdateRelocated(RawObject* raw_before, Heap* heap) {
+    heap->FreeExternal(external_size_, raw_before);
+    heap->AllocateExternal(external_size_, raw());
+  }
+
   static void Finalize(FinalizablePersistentHandle* handle) {
     Dart_WeakPersistentHandleFinalizer callback = handle->callback();
     if (callback != NULL) {
@@ -212,7 +233,11 @@
  private:
   friend class FinalizablePersistentHandles;
 
-  FinalizablePersistentHandle() : raw_(NULL), peer_(NULL), callback_(NULL) { }
+  FinalizablePersistentHandle()
+      : raw_(NULL),
+        peer_(NULL),
+        external_size_(0),
+        callback_(NULL) { }
   ~FinalizablePersistentHandle() { }
 
   // Overload the raw_ field as a next pointer when adding freed
@@ -232,11 +257,13 @@
   void Clear() {
     raw_ = Object::null();
     peer_ = NULL;
+    external_size_ = 0;
     callback_ = NULL;
   }
 
   RawObject* raw_;
   void* peer_;
+  intptr_t external_size_;

[siva, 2014/03/06 17:17:39]

Not for this CL but just a thought:
Now that we have an external field I am wondering if we should steal a bit from
here to indicate if the handle is a prolog weak persistent handle or a regular
weak persistent handle (current we tag the returned pointer).

[koda, 2014/03/06 22:55:07]

Sounds like a good idea. It would simplify the code (which became slightly more
complicated after merging with your tagging-change).

   Dart_WeakPersistentHandleFinalizer callback_;
   DISALLOW_ALLOCATION();  // Allocated through AllocateHandle methods.
   DISALLOW_COPY_AND_ASSIGN(FinalizablePersistentHandle);
@@ -438,7 +465,7 @@
       handle = reinterpret_cast<FinalizablePersistentHandle*>(
           AllocateScopedHandle());
     }
-    handle->set_callback(NULL);
+    handle->Clear();
     return handle;
   }