Finalize all classes (fix issue 364).

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 1336)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -18,8 +18,22 @@
     "Verify that all classes implement their interface.");
 DECLARE_FLAG(bool, enable_type_checks);
 
+void ClassFinalizer::ExpectPendingClasses() {

[srdjan, 2011/11/09 21:22:43]

Do you want to allow ExpectPendingClasses several times before finalizing? I.e.,
do you need to assert !AllClassFinalized().

[regis, 2011/11/09 23:31:01]

Good question!
Currently, there may be several calls to ExpectPendingClasses (e.g.
Object::Init() and Parser::ParseTopLevel()) before a call to
FinalizePendingClasses. We could force proper pairing of these calls, but we
would probably need to use a counter rather than a binary flag to allow proper
nesting.
I prefer to allow multiple calls for now.

+  if (AllClassesFinalized()) {
+    ObjectStore* object_store = Isolate::Current()->object_store();
+    object_store->set_pending_classes(Array::Handle(Array::Empty()));
+    ASSERT(!AllClassesFinalized());
+  }
+}
+
+
 void ClassFinalizer::AddPendingClasses(
     const GrowableArray<const Class*>& classes) {
+  // ExpectPendingClasses() must be called prior to calling AddPendingClasses().
+  if (AllClassesFinalized()) {  // TODO(regis): DEBUG.
+    ASSERT(false);
+  }

[srdjan, 2011/11/09 21:22:43]

Why the code above?

[regis, 2011/11/09 23:31:01]

Left over debugging code. Removed.

+  ASSERT(!AllClassesFinalized());
   if (!classes.is_empty()) {
     ObjectStore* object_store = Isolate::Current()->object_store();
     const Array& old_array = Array::Handle(object_store->pending_classes());
@@ -38,7 +52,7 @@
 bool ClassFinalizer::AllClassesFinalized() {
   ObjectStore* object_store = Isolate::Current()->object_store();
   const Array& classes = Array::Handle(object_store->pending_classes());
-  return classes.Length() == 0;
+  return classes.IsNull();
 }
 
 
@@ -59,10 +73,11 @@
   isolate->set_long_jump_base(&jump);
   if (setjmp(*jump.Set()) == 0) {
     const Array& class_array = Array::Handle(object_store->pending_classes());
-    ASSERT(!class_array.IsNull());
+    const intptr_t num_pending_classes =
+        class_array.IsNull() ? 0 : class_array.Length();
     Class& cls = Class::Handle();
     // First resolve all superclasses.
-    for (intptr_t i = 0; i < class_array.Length(); i++) {
+    for (intptr_t i = 0; i < num_pending_classes; i++) {
       cls ^= class_array.At(i);
       if (FLAG_trace_class_finalization) {
         OS::Print("Resolving super and default: %s\n", cls.ToCString());
@@ -73,18 +88,18 @@
       }
     }
     // Finalize all classes.
-    for (intptr_t i = 0; i < class_array.Length(); i++) {
+    for (intptr_t i = 0; i < num_pending_classes; i++) {
       cls ^= class_array.At(i);
       FinalizeClass(cls);
     }
     if (FLAG_print_classes) {
-      for (intptr_t i = 0; i < class_array.Length(); i++) {
+      for (intptr_t i = 0; i < num_pending_classes; i++) {
         cls ^= class_array.At(i);
         PrintClassInformation(cls);
       }
     }
     if (FLAG_verify_implements) {
-      for (intptr_t i = 0; i < class_array.Length(); i++) {
+      for (intptr_t i = 0; i < num_pending_classes; i++) {
         cls ^= class_array.At(i);
         if (!cls.is_interface()) {
           VerifyClassImplements(cls);
@@ -92,7 +107,8 @@
       }
     }
     // Clear pending classes array.
-    object_store->set_pending_classes(Array::Handle(Array::Empty()));
+    object_store->set_pending_classes(Array::Handle());
+    ASSERT(AllClassesFinalized());
 
     // Check to ensure there are no duplicate definitions in the library
     // hierarchy.
@@ -242,6 +258,38 @@
 }
 
 
+// Resolve unresolved_class in the library of cls.
+RawClass* ClassFinalizer::ResolveClass(
+    const Class& cls, const UnresolvedClass& unresolved_class) {
+  Library& lib = Library::Handle();
+  if (unresolved_class.qualifier() == String::null()) {
+    lib = cls.library();
+  } else {
+    const String& qualifier = String::Handle(unresolved_class.qualifier());
+    LibraryPrefix& lib_prefix = LibraryPrefix::Handle();
+    lib_prefix = cls.LookupLibraryPrefix(qualifier);
+    if (lib_prefix.IsNull()) {
+      const Script& script = Script::Handle(cls.script());
+      ReportError(script, unresolved_class.token_index(),
+                  "cannot resolve name '%s'\n",

[srdjan, 2011/11/09 21:22:43]

Maybe be more specific -> cannot resolve library prefix.

[regis, 2011/11/09 23:31:01]

Done.

+                  String::Handle(unresolved_class.Name()).ToCString());
+    }
+    lib = lib_prefix.library();
+  }
+  ASSERT(!lib.IsNull());
+  const String& class_name = String::Handle(unresolved_class.ident());
+  const Class& resolved_class = Class::Handle(lib.LookupClass(class_name));
+  if (resolved_class.IsNull()) {
+    const Script& script = Script::Handle(cls.script());
+    ReportError(script, unresolved_class.token_index(),
+                "cannot resolve class name '%s' from '%s'\n",
+                String::Handle(unresolved_class.Name()).ToCString(),
+                String::Handle(cls.Name()).ToCString());
+  }
+  return resolved_class.raw();
+}
+
+
 // Resolve unresolved superclasses (String -> Class).
 void ClassFinalizer::ResolveSuperClass(const Class& cls) {
   if (cls.is_finalized()) {
@@ -253,6 +301,13 @@
   }
   // Resolve failures lead to a longjmp.
   super_type = ResolveType(cls, super_type);
+  if (super_type.IsTypeParameter()) {
+    String& class_name = String::Handle(cls.Name());
+    String& type_parameter_name = String::Handle(super_type.Name());
+    ReportError("'%s' cannot extend or implement type parameter '%s'.\n",
+                class_name.ToCString(),
+                type_parameter_name.ToCString());
+  }
   cls.set_super_type(super_type);
   const Class& super_class = Class::Handle(super_type.type_class());
   if (cls.is_interface() != super_class.is_interface()) {
@@ -354,31 +409,9 @@
     }
 
     // Lookup the type class.
-    Class& type_class = Class::Handle();
-    Library& lib = Library::Handle();
-    if (unresolved_class.qualifier() == String::null()) {
-      lib = cls.library();
-    } else {
-      const String& qualifier = String::Handle(unresolved_class.qualifier());
-      LibraryPrefix& lib_prefix = LibraryPrefix::Handle();
-      lib_prefix = cls.LookupLibraryPrefix(qualifier);
-      if (lib_prefix.IsNull()) {
-        const Script& script = Script::Handle(cls.script());
-        ReportError(script, unresolved_class.token_index(),
-                    "cannot resolve name '%s'\n",
-                    String::Handle(unresolved_class.Name()).ToCString());
-      }
-      lib = lib_prefix.library();
-    }
-    ASSERT(!lib.IsNull());
-    type_class = lib.LookupClass(type_class_name);
-    if (type_class.IsNull()) {
-      const Script& script = Script::Handle(cls.script());
-      ReportError(script, unresolved_class.token_index(),
-                  "cannot resolve class name '%s' from '%s'\n",
-                  String::Handle(unresolved_class.Name()).ToCString(),
-                  String::Handle(cls.Name()).ToCString());
-    }
+    const Class& type_class =
+        Class::Handle(ResolveClass(cls, unresolved_class));
+
     // Replace unresolved class with resolved type class.
     ASSERT(type.IsParameterizedType());
     ParameterizedType& parameterized_type = ParameterizedType::Handle();
@@ -506,10 +539,18 @@
   }
 
   // The type class does not need to be finalized in order to finalize the type,
-  // however, it must at least be resolved. This was done as part of resolving
-  // the type itself.
+  // however, it must at least be resolved (this was done as part of resolving
+  // the type itself, a precondition to calling FinalizeType) and the upper
+  // bounds of its type parameters must be finalized (done here).
   Class& type_class = Class::Handle(parameterized_type.type_class());
 
+  // If the type class is a signature class, finalize it, thereby finalizing the
+  // result and parameter types of its signature function.
+  // Do this before marking this type as finalized in order to detect cycles.
+  if (type_class.IsSignatureClass()) {
+    FinalizeClass(type_class);
+  }
+
   // The finalized type argument vector needs num_type_arguments types.
   const intptr_t num_type_arguments = type_class.NumTypeArguments();
   // The type class has num_type_parameters type parameters.
@@ -545,14 +586,11 @@
     FinalizeTypeArguments(type_class, full_arguments);
     parameterized_type.set_arguments(full_arguments);
   }
+  // Mark the type as finalized before finalizing the upper bounds, because
+  // cycles via upper bounds are legal at compile time.
+  parameterized_type.set_is_finalized();
+  ResolveAndFinalizeUpperBounds(type_class);
 
-  // If the type is a function type, finalize the result and parameter types.
-  if (type_class.IsSignatureClass()) {
-    ResolveAndFinalizeSignature(
-        type_class, Function::Handle(type_class.signature_function()));
-  }
-
-  parameterized_type.set_is_finalized();
   return parameterized_type.Canonicalize();
 }
 
@@ -565,7 +603,15 @@
   LongJump jump;
   isolate->set_long_jump_base(&jump);
   if (setjmp(*jump.Set()) == 0) {
-    const Type& canonical_type = Type::Handle(FinalizeType(type));
+    Type& canonical_type = Type::Handle();
+    if (type.IsSignatureType() && !AllClassesFinalized()) {

[srdjan, 2011/11/09 21:22:43]

Maybe have a interim method: CollectingClassesToFinalize ->
!AllClassesFinalized?

[regis, 2011/11/09 23:31:01]

Done. Renamed these calls to:
ExpectClassesToFinalize
IsExpectingClassesToFinalize
AddClassesToFinalize
AllClassesFinalized
FinalizeAllClasses

+      // Postpone the finalization of this signature type and class.
+      GrowableArray<const Class*> classes;
+      classes.Add(&Class::ZoneHandle(type.type_class()));
+      ClassFinalizer::AddPendingClasses(classes);
+    } else {
+      canonical_type = FinalizeType(type);
+    }
     isolate->set_long_jump_base(base);
     *errmsg = String::null();
     return canonical_type.raw();
@@ -580,11 +626,6 @@
 }
 
 
-// Top level function signatures are canonicalized, added to the library class
-// dictionary, and finalized with other library classes and interfaces.
-// Function signatures used as type of a local variable or of a local function
-// are canonicalized and finalized upon creation, since all the types they
-// reference are already resolved.
 void ClassFinalizer::ResolveAndFinalizeSignature(const Class& cls,
                                                  const Function& function) {
   // Resolve result type.
@@ -644,6 +685,23 @@
 }
 
 
+void ClassFinalizer::ResolveAndFinalizeUpperBounds(const Class& cls) {
+  const intptr_t num_type_params = cls.NumTypeParameters();
+  Type& type_extends = Type::Handle();
+  const TypeArguments& extends_array =
+      TypeArguments::Handle(cls.type_parameter_extends());
+  ASSERT((extends_array.IsNull() && (num_type_params == 0)) ||
+         (extends_array.Length() == num_type_params));
+  for (intptr_t i = 0; i < num_type_params; i++) {
+    type_extends = extends_array.TypeAt(i);
+    type_extends = ResolveType(cls, type_extends);
+    extends_array.SetTypeAt(i, type_extends);
+    type_extends = FinalizeType(type_extends);
+    extends_array.SetTypeAt(i, type_extends);
+  }
+}
+
+
 void ClassFinalizer::ResolveAndFinalizeMemberTypes(const Class& cls) {
   // Note that getters and setters are explicitly listed as such in the list of
   // functions of a class, so we do not need to consider fields as implicitly
@@ -777,13 +835,6 @@
       }
     }
   }
-  // Resolve the signature type if this class is a signature class.
-  if (cls.IsSignatureClass()) {
-    Type& signature_type = Type::Handle(cls.SignatureType());
-    signature_type = FinalizeType(signature_type);
-    // Signature types are canonicalized by default.
-    ASSERT(signature_type.raw() == cls.SignatureType());
-  }
 }
 
 
@@ -833,9 +884,25 @@
     interface_type = FinalizeType(interface_type);
     interface_types.SetAt(i, interface_type);
   }
-  // Mark as finalized before resolving member types in order to break cycles.
+  // Mark as finalized before resolving type parameter upper bounds and member
+  // types in order to break cycles.
   cls.Finalize();
+  ResolveAndFinalizeUpperBounds(cls);
   ResolveAndFinalizeMemberTypes(cls);
+
+  if (cls.IsSignatureClass()) {
+    // Finalize the signature type of this signature class.
+    Type& signature_type = Type::Handle(cls.SignatureType());
+    signature_type = FinalizeType(signature_type);
+    // Signature types are canonicalized by default.
+    ASSERT(signature_type.raw() == cls.SignatureType());
+
+    // Resolve and finalize the result and parameter types of the signature
+    // function of this signature class.
+    ResolveAndFinalizeSignature(cls,
+                                Function::Handle(cls.signature_function()));
+  }
+
   // Run additional checks after all types are finalized.
   if (cls.is_const()) {
     CheckForLegalConstClass(cls);
@@ -964,8 +1031,6 @@
                     String::Handle(cls.Name()).ToCString(),
                     String::Handle(interface_class.Name()).ToCString());
       }
-      // TODO(regis): We also need to prevent extending classes Smi, Mint,
-      // BigInt, Double, OneByteString, TwoByteString, FourByteString.
     }
     // Now resolve the super interfaces.
     ResolveInterfaces(interface_class, visited);