[vm, dynamic modules] Bugfixes in the bytecode reader and interpreter runtime

* Never unbox fields loaded from bytecode as interpreter works with
  boxed fields only.

* Ensure classes are allocate-finalized in AllocateObject
  runtime entry as interpreter may allocate instances of certain
  built-in classes (such as _Closure, _Double etc) without prior
  allocate-finalization.

* Fix type arguments vector in constant instances when class doesn't
  have type parameters but extends a generic class (so its instances
  have type arguments vector).

TEST=ci

Change-Id: I488287f84572a79ca7f1fddbd53aed1c3a038cea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/412981
Commit-Queue: Alexander Markov <[email protected]>
Reviewed-by: Slava Egorov <[email protected]>

Author: alexmarkov

runtime/vm/bytecode_reader.cc

@@ -1075,10 +1075,12 @@ ObjectPtr BytecodeReaderHelper::ReadConstObject(intptr_t tag) {
       const Type& type = Type::CheckedHandle(Z, ReadObject());
       const Class& cls = Class::Handle(Z, type.type_class());
       const Instance& obj = Instance::Handle(Z, Instance::New(cls, Heap::kOld));
-      if (type.arguments() != TypeArguments::null()) {
-        const TypeArguments& type_args =
-            TypeArguments::Handle(Z, type.arguments());
+      if (cls.NumTypeArguments() > 0) {
+        auto& type_args = TypeArguments::Handle(Z, type.arguments());
+        type_args = cls.GetInstanceTypeArguments(thread_, type_args);
         obj.SetTypeArguments(type_args);
+      } else {
+        ASSERT(type.arguments() == TypeArguments::null());
       }
       const intptr_t num_fields = reader_.ReadUInt();
       Field& field = Field::Handle(Z);
@@ -1549,6 +1551,7 @@ void BytecodeReaderHelper::ReadFieldDeclarations(const Class& cls,
                        (flags & kIsReflectableFlag) != 0, is_late, script_class,
                        type, position, end_position);
 
+    field.set_is_unboxed(false);
     field.set_has_pragma(has_pragma);
     field.set_is_covariant((flags & kIsCovariantFlag) != 0);
     field.set_is_generic_covariant_impl((flags & kIsCovariantByClassFlag) != 0);

runtime/vm/runtime_entry.cc

@@ -536,6 +536,16 @@ static void ThrowIfError(const Object& result) {
 // Return value: newly allocated object.
 DEFINE_RUNTIME_ENTRY(AllocateObject, 2) {
   const Class& cls = Class::CheckedHandle(zone, arguments.ArgAt(0));
+#if defined(DART_DYNAMIC_MODULES) && !defined(DART_PRECOMPILED_RUNTIME)
+  if (!cls.is_allocate_finalized()) {
+    const Error& error =
+        Error::Handle(zone, cls.EnsureIsAllocateFinalized(thread));
+    if (!error.IsNull()) {
+      Exceptions::PropagateError(error);
+      UNREACHABLE();
+    }
+  }
+#endif
   ASSERT(cls.is_allocate_finalized());
   const Instance& instance = Instance::Handle(
       zone, Instance::NewAlreadyFinalized(cls, SpaceForRuntimeAllocation()));