Create explicit cown region

Author: mjp41

src/rt/core.h

@@ -58,8 +58,7 @@ namespace rt::core
   class FuncObject : public objects::DynObject
   {
   public:
-    FuncObject(objects::DynObject* prototype_)
-    : objects::DynObject(prototype_)
+    FuncObject(objects::DynObject* prototype_) : objects::DynObject(prototype_)
     {}
   };
 
@@ -197,7 +196,7 @@ namespace rt::core
   {
   public:
     CownObject(objects::DynObject* region)
-    : objects::DynObject(cownPrototypeObject())
+    : objects::DynObject(cownPrototypeObject(), objects::cown_region)
     {
       // FIXME: Add once regions are reified
       // assert(
@@ -232,11 +231,6 @@ namespace rt::core
       // always be opaque.
       return true;
     }
-
-    bool is_cown() override
-    {
-      return true;
-    }
   };
 
   inline std::set<objects::DynObject*>* globals()

src/rt/objects/dyn_object.h

@@ -79,7 +79,9 @@ namespace rt::objects
     }
 
     // prototype is borrowed, the caller does not need to provide an RC.
-    DynObject(DynObject* prototype_ = nullptr, Region* containing_region = get_local_region())
+    DynObject(
+      DynObject* prototype_ = nullptr,
+      Region* containing_region = get_local_region())
     : prototype(prototype_)
     {
       assert(containing_region != nullptr);
@@ -146,24 +148,24 @@ namespace rt::objects
       return false;
     }
 
-    virtual bool is_cown()
+    bool is_cown()
     {
-      return false;
+      return region.get_ptr() == objects::cown_region;
     }
 
     void freeze()
     {
       // TODO SCC algorithm
       visit(this, [](Edge e) {
         auto obj = e.target;
-        if (!obj || obj->is_immutable())
+        if (!obj || obj->is_immutable() || obj->is_cown())
           return false;
 
         auto r = get_region(obj);
         get_region(obj)->objects.erase(obj);
         obj->region.set_ptr(immutable_region);
 
-        return !obj->is_cown();
+        return true;
       });
     }
 

src/rt/objects/region.cc

@@ -77,6 +77,10 @@ namespace rt::objects
     if (target == immutable_region)
       return;
 
+    // Handle cown case
+    if (target == cown_region)
+      return;
+
     if (src == get_local_region())
     {
       Region::dec_lrc(target);
@@ -152,7 +156,7 @@ namespace rt::objects
   {
     assert(src != nullptr);
     assert(dst != nullptr);
-    if (target == nullptr || target->is_immutable())
+    if (target == nullptr || target->is_immutable() || target->is_cown())
       return;
 
     auto src_region = get_region(src);

src/rt/objects/region.h

@@ -181,4 +181,7 @@ namespace rt::objects
 
   inline Region immutable_region_impl;
   inline constexpr Region* immutable_region{&immutable_region_impl};
+
+  inline Region cown_region_impl;
+  inline constexpr Region* cown_region{&cown_region_impl};
 } // namespace rt::objects