Do not eagerly finalize classes in CHA, instead regard unfinalized classes as ’non-existent’ an…

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 30540)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -89,20 +89,15 @@
 // Use array instead of set since we expect very few subclassed classes
 // to occur.
 static void CollectFinalizedSuperClasses(
-    const GrowableObjectArray& pending_classes,
-    GrowableArray<intptr_t>* finalized_super_classes) {
-  Class& cls = Class::Handle();
+    const Class& cls_, GrowableArray<intptr_t>* finalized_super_classes) {
+  Class& cls = Class::Handle(cls_.raw());
   AbstractType& super_type = Type::Handle();
-  for (intptr_t i = 0; i < pending_classes.Length(); i++) {
-    cls ^= pending_classes.At(i);
-    ASSERT(!cls.is_finalized());
-    super_type = cls.super_type();
-    if (!super_type.IsNull()) {
-      if (!super_type.IsMalformed() && super_type.HasResolvedTypeClass()) {
-        cls ^= super_type.type_class();
-        if (cls.is_finalized()) {
-          AddSuperType(super_type, finalized_super_classes);
-        }
+  super_type = cls.super_type();
+  if (!super_type.IsNull()) {
+    if (!super_type.IsMalformed() && super_type.HasResolvedTypeClass()) {
+      cls ^= super_type.type_class();
+      if (cls.is_finalized()) {
+        AddSuperType(super_type, finalized_super_classes);
       }
     }
   }
@@ -112,7 +107,7 @@
 // Class finalization occurs:
 // a) when bootstrap process completes (VerifyBootstrapClasses).
 // b) after the user classes are loaded (dart_api).
-bool ClassFinalizer::FinalizePendingClasses() {
+bool ClassFinalizer::FinalizePendingClassInterfaces() {

[Ivan Posva, 2013/11/21 23:04:09]

This is not finalizing the class's interface. Actually we go to great pains to
not deal with the class' s interface (its methods and fields) here. What we are
finalizing at this point is the type hierarchy.

[srdjan, 2013/11/22 00:08:14]

Renaming to FinalizeTypeHierarchy

   bool retval = true;
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
@@ -126,7 +121,6 @@
     return true;
   }
 
-  GrowableArray<intptr_t> added_subclasses_to_cids;
   LongJump* base = isolate->long_jump_base();
   LongJump jump;
   isolate->set_long_jump_base(&jump);
@@ -134,9 +128,6 @@
     GrowableObjectArray& class_array = GrowableObjectArray::Handle();
     class_array = object_store->pending_classes();
     ASSERT(!class_array.IsNull());
-    // Collect superclasses that were already finalized before this run of
-    // finalization.
-    CollectFinalizedSuperClasses(class_array, &added_subclasses_to_cids);
     Class& cls = Class::Handle();
     // First resolve all superclasses.
     for (intptr_t i = 0; i < class_array.Length(); i++) {
@@ -163,9 +154,6 @@
     retval = false;
   }
   isolate->set_long_jump_base(base);
-  if (FLAG_use_cha) {
-    RemoveOptimizedCode(added_subclasses_to_cids);
-  }
   return retval;
 }
 
@@ -238,7 +226,7 @@
   }
 
   // Finalize classes that aren't pre-finalized by Object::Init().
-  if (!FinalizePendingClasses()) {
+  if (!FinalizePendingClassInterfaces()) {
     // TODO(srdjan): Exit like a real VM instead.
     const Error& err = Error::Handle(object_store->sticky_error());
     OS::PrintErr("Could not verify bootstrap classes : %s\n",
@@ -2054,6 +2042,8 @@
     // the class conflict with inherited methods.
     ApplyMixinMembers(cls);
   }
+  GrowableArray<intptr_t> added_subclasses_to_cids;
+  CollectFinalizedSuperClasses(cls, &added_subclasses_to_cids);
   // Ensure super class is finalized.
   const Class& super = Class::Handle(cls.SuperClass());
   if (!super.IsNull()) {
@@ -2081,6 +2071,9 @@
   if (cls.is_const()) {
     CheckForLegalConstClass(cls);
   }
+  if (FLAG_use_cha) {
+    RemoveOptimizedCode(added_subclasses_to_cids);

[Ivan Posva, 2013/11/21 23:04:09]

This will add Object to the list, but Object never is a candidate for CHA as far
as I can tell.

[srdjan, 2013/11/22 00:08:14]

Modified CollectFinalizedSuperClasses to exclude object type.

+  }
 }