Canonicalize types.

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 431 matching lines @@
             const String& type_name = String::Handle(type.Name());
             const String& extends_name = String::Handle(type_extends.Name());
             ReportError("type argument '%s' does not extend type '%s'\n",
                         type_name.ToCString(),
                         extends_name.ToCString());
           }
         }
       }
     }
   }
-  const Type& super_type = Type::Handle(cls.super_type());
+  Type& super_type = Type::Handle(cls.super_type());
   if (!super_type.IsNull()) {
     FinalizeType(super_type);
+    super_type = super_type.Canonicalize();

[srdjan, 2011/11/01 20:51:43]

Do you need to finalize the super_type that you may actually be throwing away?
Maybe call FinalizeType after getting the type's canonical version?

[regis, 2011/11/01 21:54:50]

The finalized and canonicalized super type is written back to the class on the
following line. So this is not wasted work.

[srdjan, 2011/11/01 22:05:14]

As I understand it the canonical super_type could already have been finalized,
so the finalization of 'rejected' super_type instance is wasted. However, it
seems from otehr comments that you need to finalize in order to properly search
for canonical version.

[regis, 2011/11/01 22:28:53]

If the super_type was already finalized, the call to FinalizeType returns
immediately. In that case, the only wasted work is to canonicalize again. This
is why I will try to combine finalization with canonicalization. 

+    cls.set_super_type(super_type);
     const Class& super_class = Class::Handle(super_type.type_class());
     const TypeArguments& super_type_args =
         TypeArguments::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()));
     Type& super_type_arg = Type::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.Canonicalize();

[srdjan, 2011/11/01 20:51:43]

I assume you cannot ask for proper canonical version until you have instantiated
it?

[regis, 2011/11/01 21:54:50]

Correct. We want to canonicalize the finalized output type, with instantiated
type parameters of its super types.

       arguments.SetTypeAt(super_offset + i, super_type_arg);
     }
     FinalizeTypeArguments(super_class, arguments);
   }
 }
 
 
 void ClassFinalizer::FinalizeType(const Type& type) {
   ASSERT(type.IsResolved());
   if (type.IsFinalized()) {
@@ skipping 14 matching lines @@
 
   // Finalize the current type arguments of the type, which are still the
   // parsed type arguments.
   TypeArguments& arguments =
       TypeArguments::Handle(parameterized_type.arguments());
   if (!arguments.IsNull()) {
     intptr_t num_arguments = arguments.Length();
     for (intptr_t i = 0; i < num_arguments; i++) {
       Type& type_argument = Type::Handle(arguments.TypeAt(i));
       FinalizeType(type_argument);
+      type_argument = type_argument.Canonicalize();

[srdjan, 2011/11/01 20:51:43]

Ditto here, Finalize after Canonicalize or is there something that happens that
you need from finalization?

[regis, 2011/11/01 21:54:50]

Finalization may instantiate type arguments, so it does not make sense to
canonicalize before finalization.
I may try to canonicalize as part of finalization, instead of having two
separate calls. Would that be clearer?

+      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.
   Class& type_class = Class::Handle(parameterized_type.type_class());
 
   // The finalized type argument vector needs num_type_arguments types.
   const intptr_t num_type_arguments = type_class.NumTypeArguments();
@@ skipping 34 matching lines @@
   // 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();
 }
 
 
-RawString* ClassFinalizer::FinalizeTypeWhileParsing(const Type& type) {
+RawType* ClassFinalizer::FinalizeAndCanonicalizeType(const Type& 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) {
     FinalizeType(type);
     isolate->set_long_jump_base(base);
-    return String::null();
+    errmsg = String::null();
+    return type.Canonicalize();
   } else {
     // Error occured: Get the error message.
     isolate->set_long_jump_base(base);
-    return isolate->object_store()->sticky_error();
+    errmsg = isolate->object_store()->sticky_error();
+    return type.raw();
   }
   UNREACHABLE();
-  return String::null();
+  return Type::null();
 }
 
 
 // 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.
   Type& type = Type::Handle(function.result_type());
   type = ResolveType(cls, type);
   function.set_result_type(type);
   FinalizeType(type);
+  type = type.Canonicalize();
+  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);
     type = ResolveType(cls, type);
     function.SetParameterTypeAt(i, type);
     FinalizeType(type);
+    type = type.Canonicalize();
+    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();
   super_class = cls.SuperClass();
@@ skipping 48 matching lines @@
   Type& type = Type::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();
     type = ResolveType(cls, type);
     field.set_type(type);
     FinalizeType(type);
+    type = type.Canonicalize();
+    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());
       ReportError("field '%s' of class '%s' conflicts with instance "
                   "member '%s' of super class '%s'.\n",
                   name.ToCString(),
                   class_name.ToCString(),
                   name.ToCString(),
@@ skipping 91 matching lines @@
                     class_name.ToCString(),
                     function_name.ToCString(),
                     super_class_name.ToCString());
       }
     }
   }
   // Resolve the signature type if this class is a signature class.
   if (cls.IsSignatureClass()) {
     const Type& signature_type = Type::Handle(cls.SignatureType());
     FinalizeType(signature_type);
+    // Signature types are canonicalized by default.
   }
 }
 
 
 void ClassFinalizer::FinalizeClass(const Class& cls) {
   if (cls.is_finalized()) {
     return;
   }
   if (FLAG_trace_class_finalization) {
     OS::Print("Finalize %s\n", cls.ToCString());
   }
   if (!IsSuperCycleFree(cls)) {
     const String& name = String::Handle(cls.Name());
     ReportError("class '%s' has a cycle in its superclass relationship.\n",
                 name.ToCString());
   }
   GrowableArray<const Class*> visited;
   ResolveInterfaces(cls, &visited);
-  const Type& super_type = Type::Handle(cls.super_type());
+  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);
     FinalizeType(super_type);
+    super_type = super_type.Canonicalize();
+    cls.set_super_type(super_type);
   }
   if (cls.is_interface()) {
-    const Type& factory_type = Type::Handle(cls.factory_type());
+    Type& factory_type = Type::Handle(cls.factory_type());
     if (!factory_type.IsNull()) {
       const Class& factory_class = Class::Handle(factory_type.type_class());
       // Finalize factory class and factory type.
       if (!factory_class.is_finalized()) {
         FinalizeClass(factory_class);
         // Finalizing the factory class may indirectly finalize this interface.
         if (cls.is_finalized()) {
           return;
         }
       }
       FinalizeType(factory_type);
+      factory_type = factory_type.Canonicalize();
+      cls.set_factory_type(factory_type);
     }
   }
   // Finalize interface types (but not necessarily interface classes).
   Array& interface_types = Array::Handle(cls.interfaces());
   Type& interface_type = Type::Handle();
   for (intptr_t i = 0; i < interface_types.Length(); i++) {
     interface_type ^= interface_types.At(i);
     FinalizeType(interface_type);
+    interface_type = interface_type.Canonicalize();
+    interface_types.SetAt(i, interface_type);
   }
   // Mark as finalized before resolving member types in order to break cycles.
   cls.Finalize();
   ResolveAndFinalizeMemberTypes(cls);
   // Run additional checks after all types are finalized.
   if (cls.is_const()) {
     CheckForLegalConstClass(cls);
   }
 }
 
@@ skipping 239 matching lines @@
   ASSERT(msg_buffer != NULL);
   va_list args;
   va_start(args, format);
   OS::VSNPrint(msg_buffer, kBufferLength, format, args);
   va_end(args);
   isolate->long_jump_base()->Jump(1, msg_buffer);
   UNREACHABLE();
 }
 
 }  // namespace dart