Adjust index of type parameters at finalization time (fix issue 718).

runtime/vm/class_finalizer.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/class_finalizer.h"
 
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
@@ skipping 467 matching lines @@
 
 // Finalize the type argument vector 'arguments' of the type defined by the
 // class 'cls' parameterized with the type arguments 'cls_args'.
 // The vector 'cls_args' is already initialized as a subvector at the correct
 // position in the passed in 'arguments' vector.
 // The subvector 'cls_args' has length cls.NumTypeParameters() and starts at
 // offset cls.NumTypeArguments() - cls.NumTypeParameters() of the 'arguments'
 // vector.
 // Example:
 //   Declared: class C<K, V> extends B<V> { ... }
-//             class B<T> extends Array<int> { ... }
+//             class B<T> extends A<int> { ... }
 //   Input:    C<String, double> expressed as
 //             cls = C, arguments = [null, null, String, double],
 //             i.e. cls_args = [String, double], offset = 2, length = 2.
 //   Output:   arguments = [int, double, String, double]
 void ClassFinalizer::FinalizeTypeArguments(
     const Class& cls, const AbstractTypeArguments& arguments) {
   ASSERT(arguments.Length() >= cls.NumTypeArguments());
   Type& super_type = Type::Handle(cls.super_type());
   if (!super_type.IsNull()) {
-    super_type ^= FinalizeType(super_type);
+    super_type ^= FinalizeType(cls, super_type);
     cls.set_super_type(super_type);
     const Class& super_class = Class::Handle(super_type.type_class());
     const AbstractTypeArguments& super_type_args =
         AbstractTypeArguments::Handle(super_type.arguments());
     const intptr_t num_super_type_params = super_class.NumTypeParameters();
     const intptr_t offset = super_class.NumTypeArguments();
     const intptr_t super_offset = offset - num_super_type_params;
     ASSERT(offset == (cls.NumTypeArguments() - cls.NumTypeParameters()));
     AbstractType& super_type_arg = AbstractType::Handle();
     for (intptr_t i = 0; i < num_super_type_params; i++) {
       super_type_arg = super_type_args.TypeAt(super_offset + i);
       if (!super_type_arg.IsInstantiated()) {
-        super_type_arg = super_type_arg.InstantiateFrom(arguments, offset);
+        super_type_arg = super_type_arg.InstantiateFrom(arguments);
       }
       super_type_arg = super_type_arg.Canonicalize();
       arguments.SetTypeAt(super_offset + i, super_type_arg);
     }
     FinalizeTypeArguments(super_class, arguments);
   }
 }
 
 
 // Verify the upper bounds of the type arguments of class cls.
 void ClassFinalizer::VerifyUpperBounds(const Class& cls,
                                        const AbstractTypeArguments& arguments) {
   ASSERT(FLAG_enable_type_checks);
   ASSERT(arguments.Length() >= cls.NumTypeArguments());
   const intptr_t num_type_params = cls.NumTypeParameters();
   const intptr_t offset = cls.NumTypeArguments() - num_type_params;
   AbstractType& type = AbstractType::Handle();
   AbstractType& type_extends = AbstractType::Handle();
   const AbstractTypeArguments& extends_array =
       AbstractTypeArguments::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);
     if (!type_extends.IsDynamicType()) {
       type = arguments.TypeAt(offset + i);
       if (type.IsInstantiated()) {
         if (!type_extends.IsInstantiated()) {
-          type_extends = type_extends.InstantiateFrom(arguments, offset);
+          type_extends = type_extends.InstantiateFrom(arguments);
         }
         // TODO(regis): Where do we check the constraints when the type is
         // generic?
         if (!type.IsSubtypeOf(type_extends)) {
           const String& type_argument_name = String::Handle(type.Name());
           const String& class_name = String::Handle(cls.Name());
           const String& extends_name = String::Handle(type_extends.Name());
           const Script& script = Script::Handle(cls.script());
           ReportError(script, -1,
                       "type argument '%s' of class '%s' "
                       "does not extend type '%s'\n",
                       type_argument_name.ToCString(),
                       class_name.ToCString(),
                       extends_name.ToCString());
         }
       }
     }
   }
   const Type& super_type = Type::Handle(cls.super_type());
   if (!super_type.IsNull()) {
     ASSERT(super_type.IsFinalized());
     const Class& super_class = Class::Handle(super_type.type_class());
     VerifyUpperBounds(super_class, arguments);
   }
 }
 
 
-RawAbstractType* ClassFinalizer::FinalizeType(const AbstractType& type) {
+RawAbstractType* ClassFinalizer::FinalizeType(const Class& cls,
+                                              const AbstractType& type) {
   ASSERT(type.IsResolved());
   if (type.IsFinalized()) {
     return type.raw();
   }
   if (FLAG_trace_type_finalization) {
     OS::Print("Finalize type '%s'\n", String::Handle(type.Name()).ToCString());
   }
 
+  if (type.IsTypeParameter()) {
+    ASSERT(!cls.IsNull());
+    TypeParameter& type_parameter = TypeParameter::Handle();
+    type_parameter ^= type.raw();
+    // The index must reflect the position of this type parameter in the type
+    // arguments vector of the enclosing class. The offset to add is the number
+    // of type arguments in the super type, which is equal to the difference in
+    // number of type arguments and type parameters of the enclosing class.
+    const intptr_t offset = cls.NumTypeArguments() - cls.NumTypeParameters();
+    type_parameter.set_index(type_parameter.Index() + offset);
+    type_parameter.set_is_finalized();
+    // We do not canonicalize type parameters.
+    return type_parameter.raw();
+  }
+
   // At this point, we can only have a parameterized_type.
   Type& parameterized_type = Type::Handle();
   parameterized_type ^= type.raw();
 
   if (parameterized_type.IsBeingFinalized()) {
     ReportError("type '%s' illegally refers to itself\n",
                 String::Handle(parameterized_type.Name()).ToCString());
   }
 
   // Mark type as being finalized in order to detect illegal self reference.
   parameterized_type.set_is_being_finalized();
 
   // Finalize the current type arguments of the type, which are still the
   // parsed type arguments.
   AbstractTypeArguments& arguments =
       AbstractTypeArguments::Handle(parameterized_type.arguments());
   if (!arguments.IsNull()) {
     intptr_t num_arguments = arguments.Length();
     for (intptr_t i = 0; i < num_arguments; i++) {
       AbstractType& type_argument = AbstractType::Handle(arguments.TypeAt(i));
-      type_argument = FinalizeType(type_argument);
+      type_argument = FinalizeType(cls, type_argument);
       arguments.SetTypeAt(i, type_argument);
     }
   }
 
   // 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, 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());
 
@@ skipping 64 matching lines @@
     if (FLAG_enable_type_checks) {
       VerifyUpperBounds(type_class, full_arguments);
     }
   } else {
     parameterized_type.set_is_finalized();
   }
   return parameterized_type.Canonicalize();
 }
 
 
-RawType* ClassFinalizer::FinalizeAndCanonicalizeType(const Type& type,
-                                                     String* errmsg) {
+RawAbstractType* ClassFinalizer::FinalizeAndCanonicalizeType(
+    const Class& cls,
+    const AbstractType& type,
+    String* errmsg) {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   LongJump* base = isolate->long_jump_base();
   LongJump jump;
   isolate->set_long_jump_base(&jump);
   if (setjmp(*jump.Set()) == 0) {
-    Type& canonical_type = Type::Handle();
-    canonical_type ^= FinalizeType(type);
+    const AbstractType& finalized_type =
+        AbstractType::Handle(FinalizeType(cls, type));
     isolate->set_long_jump_base(base);
     *errmsg = String::null();
-    return canonical_type.raw();
+    return finalized_type.raw();
   } else {
     // Error occured: Get the error message.
     isolate->set_long_jump_base(base);
     *errmsg = isolate->object_store()->sticky_error();
     return type.raw();
   }
   UNREACHABLE();
   return NULL;
 }
 
@@ skipping 42 matching lines @@
                       "factory method '%s' must declare %d type parameter%s.\n",
                       function_name.ToCString(),
                       type_class.NumTypeParameters(),
                       type_class.NumTypeParameters() > 1 ? "s" : "");
         }
       }
     } else {
       ResolveType(cls, type);
     }
   }
-  type = FinalizeType(type);
+  type = FinalizeType(cls, type);
   function.set_result_type(type);
   // Resolve formal parameter types.
   const intptr_t num_parameters = function.NumberOfParameters();
   for (intptr_t i = 0; i < num_parameters; i++) {
     type = function.ParameterTypeAt(i);
     ResolveType(cls, type);
-    type = FinalizeType(type);
+    type = FinalizeType(cls, type);
     function.SetParameterTypeAt(i, type);
   }
 }
 
 
 static RawClass* FindSuperOwnerOfInstanceMember(const Class& cls,
                                                 const String& name) {
   Class& super_class = Class::Handle();
   Function& function = Function::Handle();
   Field& field = Field::Handle();
@@ skipping 35 matching lines @@
 void ClassFinalizer::ResolveAndFinalizeUpperBounds(const Class& cls) {
   const intptr_t num_type_params = cls.NumTypeParameters();
   AbstractType& type_extends = AbstractType::Handle();
   const AbstractTypeArguments& extends_array =
       AbstractTypeArguments::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);
     ResolveType(cls, type_extends);
-    type_extends = FinalizeType(type_extends);
+    type_extends = FinalizeType(cls, 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
   // generating getters and setters.
   // The only compile errors we report are therefore:
   // - a getter having the same name as a method (but not a getter) in a super
   //   class or in a subclass.
   // - a setter having the same name as a method (but not a setter) in a super
   //   class or in a subclass.
   // - a static field, instance field, or static method (but not an instance
   //   method) having the same name as an instance member in a super class.
 
   // Resolve type of fields and check for conflicts in super classes.
   Array& array = Array::Handle(cls.fields());
   Field& field = Field::Handle();
   AbstractType& type = AbstractType::Handle();
   String& name = String::Handle();
   Class& super_class = Class::Handle();
   intptr_t num_fields = array.Length();
   for (intptr_t i = 0; i < num_fields; i++) {
     field ^= array.At(i);
     type = field.type();
     ResolveType(cls, type);
-    type = FinalizeType(type);
+    type = FinalizeType(cls, type);
     field.set_type(type);
     name = field.name();
     super_class = FindSuperOwnerOfInstanceMember(cls, name);
     if (!super_class.IsNull()) {
       const String& class_name = String::Handle(cls.Name());
       const String& super_class_name = String::Handle(super_class.Name());
       const Script& script = Script::Handle(cls.script());
       ReportError(script, field.token_index(),
                   "field '%s' of class '%s' conflicts with instance "
                   "member '%s' of super class '%s'.\n",
@@ skipping 128 matching lines @@
                 "class '%s' has a cycle in its superclass relationship.\n",
                 name.ToCString());
   }
   GrowableArray<const Class*> visited;
   ResolveInterfaces(cls, &visited);
   Type& super_type = Type::Handle(cls.super_type());
   if (!super_type.IsNull()) {
     const Class& super_class = Class::Handle(super_type.type_class());
     // Finalize super class and super type.
     FinalizeClass(super_class, generating_snapshot);
-    super_type ^= FinalizeType(super_type);
+    super_type ^= FinalizeType(cls, super_type);
     cls.set_super_type(super_type);
   }
   if (cls.is_interface()) {
     if (cls.HasFactoryClass()) {
       const Class& factory_class = Class::Handle(cls.FactoryClass());
       // Finalize factory class.
       if (!factory_class.is_finalized()) {
         FinalizeClass(factory_class, generating_snapshot);
         // Finalizing the factory class may indirectly finalize this interface.
         if (cls.is_finalized()) {
           return;
         }
       }
     }
   }
   // Finalize interface types (but not necessarily interface classes).
   Array& interface_types = Array::Handle(cls.interfaces());
   AbstractType& interface_type = AbstractType::Handle();
   for (intptr_t i = 0; i < interface_types.Length(); i++) {
     interface_type ^= interface_types.At(i);
-    interface_type = FinalizeType(interface_type);
+    interface_type = FinalizeType(cls, interface_type);
     interface_types.SetAt(i, interface_type);
   }
   // Mark as finalized before resolving type parameter upper bounds and member
   // types in order to break cycles.
   cls.Finalize();
   ResolveAndFinalizeUpperBounds(cls);
   ResolveAndFinalizeMemberTypes(cls);
   // Run additional checks after all types are finalized.
   if (cls.is_const()) {
     CheckForLegalConstClass(cls);
@@ skipping 264 matching lines @@
   va_end(args);
   if (FLAG_warning_as_error) {
     Isolate::Current()->long_jump_base()->Jump(1, message_buffer);
     UNREACHABLE();
   } else {
     OS::Print(message_buffer);
   }
 }
 
 }  // namespace dart