VM: Support bootstrapping core libraries from Kernel binaries instead of source.

runtime/vm/class_finalizer.cc

 // Copyright (c) 2013, 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/code_generator.h"
 #include "vm/flags.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
@@ skipping 100 matching lines @@
       }
     }
     cids->Add(ifc.id());
   }
 }
 
 
 // Processing ObjectStore::pending_classes_ occurs:
 // a) when bootstrap process completes (VerifyBootstrapClasses).
 // b) after the user classes are loaded (dart_api).
-bool ClassFinalizer::ProcessPendingClasses() {
+bool ClassFinalizer::ProcessPendingClasses(bool from_kernel) {
   Thread* thread = Thread::Current();
   NOT_IN_PRODUCT(TimelineDurationScope tds(thread, Timeline::GetIsolateStream(),
                                            "ProcessPendingClasses"));
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   HANDLESCOPE(thread);
   ObjectStore* object_store = isolate->object_store();
   const Error& error = Error::Handle(thread->zone(), thread->sticky_error());
   if (!error.IsNull()) {
     return false;
@@ skipping 11 matching lines @@
     // First resolve all superclasses.
     for (intptr_t i = 0; i < class_array.Length(); i++) {
       cls ^= class_array.At(i);
       GrowableArray<intptr_t> visited_interfaces;
       ResolveSuperTypeAndInterfaces(cls, &visited_interfaces);
     }
     // Finalize all classes.
     for (intptr_t i = 0; i < class_array.Length(); i++) {
       cls ^= class_array.At(i);
       FinalizeTypesInClass(cls);
+      // Classes compiled from Dart sources are finalized more lazily, classes
+      // compiled from Kernel binaries can be finalized now (and should be,
+      // since we will not revisit them).
+      if (from_kernel) {
+        FinalizeClass(cls);
+      }
     }
     if (FLAG_print_classes) {
       for (intptr_t i = 0; i < class_array.Length(); i++) {
         cls ^= class_array.At(i);
         PrintClassInformation(cls);
       }
     }
     // Clear pending classes array.
     class_array = GrowableObjectArray::New();
     object_store->set_pending_classes(class_array);
@@ skipping 18 matching lines @@
   Class& interface_class = Class::Handle(zone);
   for (intptr_t i = 0; i < interface_array.Length(); i++) {
     interface ^= interface_array.At(i);
     interface_class = interface.type_class();
     collected->Add(&Class::ZoneHandle(zone, interface_class.raw()));
     CollectInterfaces(interface_class, collected);
   }
 }
 
 
-#if defined(DART_NO_SNAPSHOT)
 void ClassFinalizer::VerifyBootstrapClasses() {
   if (FLAG_trace_class_finalization) {
     OS::Print("VerifyBootstrapClasses START.\n");
   }
   ObjectStore* object_store = Isolate::Current()->object_store();
 
   Class& cls = Class::Handle();
 #if defined(DEBUG)
   // Basic checking.
   cls = object_store->object_class();
@@ skipping 45 matching lines @@
     const Error& err = Error::Handle(Thread::Current()->sticky_error());
     OS::PrintErr("Could not verify bootstrap classes : %s\n",
                  err.ToErrorCString());
     OS::Exit(255);
   }
   if (FLAG_trace_class_finalization) {
     OS::Print("VerifyBootstrapClasses END.\n");
   }
   Isolate::Current()->heap()->Verify();
 }
-#endif  // defined(DART_NO_SNAPSHOT).
 
 
 static bool IsLoaded(const Type& type) {
   if (type.HasResolvedTypeClass()) {
     return true;
   }
   const UnresolvedClass& unresolved_class =
       UnresolvedClass::Handle(type.unresolved_class());
-  const LibraryPrefix& prefix =
-      LibraryPrefix::Handle(unresolved_class.library_prefix());
-  return prefix.IsNull() || prefix.is_loaded();
+  const Object& prefix =
+      Object::Handle(unresolved_class.library_or_library_prefix());
+  if (prefix.IsNull()) {
+    return true;
+  } else if (prefix.IsLibraryPrefix()) {
+    return LibraryPrefix::Cast(prefix).is_loaded();
+  } else {
+    return true;
+  }
 }
 
 
 // Resolve unresolved_class in the library of cls, or return null.
 RawClass* ClassFinalizer::ResolveClass(
     const Class& cls,
     const UnresolvedClass& unresolved_class) {
   const String& class_name = String::Handle(unresolved_class.ident());
   Library& lib = Library::Handle();
   Class& resolved_class = Class::Handle();
-  if (unresolved_class.library_prefix() == LibraryPrefix::null()) {
+  if (unresolved_class.library_or_library_prefix() == Object::null()) {
     lib = cls.library();
     ASSERT(!lib.IsNull());
     resolved_class = lib.LookupClass(class_name);
   } else {
-    LibraryPrefix& lib_prefix = LibraryPrefix::Handle();
-    lib_prefix = unresolved_class.library_prefix();
-    ASSERT(!lib_prefix.IsNull());
-    resolved_class = lib_prefix.LookupClass(class_name);
+    const Object& prefix =
+        Object::Handle(unresolved_class.library_or_library_prefix());
+
+    if (prefix.IsLibraryPrefix()) {
+      resolved_class = LibraryPrefix::Cast(prefix).LookupClass(class_name);
+    } else {
+      resolved_class = Library::Cast(prefix).LookupClass(class_name);
+    }
   }
   return resolved_class.raw();
 }
 
 
 void ClassFinalizer::ResolveRedirectingFactory(const Class& cls,
                                                const Function& factory) {
   const Function& target = Function::Handle(factory.RedirectionTarget());
   if (target.IsNull()) {
     Type& type = Type::Handle(factory.RedirectionType());
@@ skipping 1884 matching lines @@
 
   if (FLAG_trace_class_finalization) {
     THR_Print("Applying mixin members of %s to %s at pos %s\n",
               mixin_cls.ToCString(), cls.ToCString(),
               cls.token_pos().ToCString());
   }
 
   const GrowableObjectArray& cloned_funcs =
       GrowableObjectArray::Handle(zone, GrowableObjectArray::New());
 
-  CreateForwardingConstructors(cls, mixin_cls, cloned_funcs);
-
   Array& functions = Array::Handle(zone);
   Function& func = Function::Handle(zone);
+
   // The parser creates the mixin application class with no functions.
-  ASSERT((functions = cls.functions(), functions.Length() == 0));
+  // But the Kernel frontend will generate mixin classes with only
+  // constructors inside them, which forward to the base class constructors.
+  //
+  // => We generate the constructors if they are not already there.
+  functions = cls.functions();
+  if (functions.Length() == 0) {
+    CreateForwardingConstructors(cls, mixin_cls, cloned_funcs);
+  } else {
+    for (intptr_t i = 0; i < functions.Length(); i++) {
+      func ^= functions.At(i);
+      ASSERT(func.kernel_function() != 0);
+      cloned_funcs.Add(func);
+    }
+  }
+
   // Now clone the functions from the mixin class.
   functions = mixin_cls.functions();
   const intptr_t num_functions = functions.Length();
   for (intptr_t i = 0; i < num_functions; i++) {
     func ^= functions.At(i);
     if (func.IsGenerativeConstructor()) {
       // A mixin class must not have explicit constructors.
       if (!func.IsImplicitConstructor()) {
         const Script& script = Script::Handle(cls.script());
         const Error& error = Error::Handle(LanguageError::NewFormatted(
@@ skipping 169 matching lines @@
   } else {
     // This class should not contain any functions or user-defined fields yet,
     // because it has not been compiled yet. There may however be metadata
     // fields because type parameters are parsed before the class body. Since
     // 'ResolveAndFinalizeMemberTypes(cls)' has not been called yet, unfinalized
     // member types could choke the snapshotter.
     // Or
     // if the class is being refinalized because a patch is being applied
     // after the class has been finalized then it is ok for the class to have
     // functions.
-    ASSERT((Array::Handle(cls.functions()).Length() == 0) ||
-           cls.is_refinalize_after_patch());
+    //
+    // TODO(kmillikin): This ASSERT will fail when bootstrapping from Kernel
+    // because classes are first created, methods are added, and then classes
+    // are finalized.  It is not easy to finalize classes earlier because not
+    // all bootstrap classes have been created yet.  It would be possible to
+    // create all classes, delay adding methods, finalize the classes, and then
+    // reprocess all classes to add methods, but that seems unnecessary.
+    // Marking the bootstrap classes as is_refinalize_after_patch seems cute but
+    // it causes other things to fail by violating their assumptions.  Reenable
+    // this ASSERT if it's important, remove it if it's just a sanity check and
+    // not required for correctness.
+    //
+    // ASSERT((Array::Handle(cls.functions()).Length() == 0) ||
+    //        cls.is_refinalize_after_patch());
   }
 }
 
 
 void ClassFinalizer::FinalizeClass(const Class& cls) {
   Thread* thread = Thread::Current();
   HANDLESCOPE(thread);
   ASSERT(cls.is_type_finalized());
   if (cls.is_finalized()) {
     return;
@@ skipping 868 matching lines @@
   ASSERT(fields_array.Length() == ByteBuffer::NumberOfFields());
   field ^= fields_array.At(0);
   ASSERT(field.Offset() == ByteBuffer::data_offset());
   name ^= field.name();
   expected_name ^= String::New("_data");
   ASSERT(String::EqualsIgnoringPrivateKey(name, expected_name));
 #endif
 }
 
 }  // namespace dart