Tests for GuardField length check along with bug fixes

runtime/vm/object.cc

 // Copyright (c) 2012, 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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 5344 matching lines @@
   } else {
     result.SetOffset(0);
   }
   result.set_is_final(is_final);
   result.set_is_const(is_const);
   result.set_owner(owner);
   result.set_token_pos(token_pos);
   result.set_has_initializer(false);
   result.set_guarded_cid(kIllegalCid);
   result.set_is_nullable(false);
-  result.set_guarded_list_length(Field::kUnknownFixedLength);
+  // Presently, we only attempt to remember the list length for final fields.
+  if (is_final) {
+    result.set_guarded_list_length(Field::kUnknownFixedLength);
+  } else {
+    result.set_guarded_list_length(Field::kNoFixedLength);
+  }
   result.set_dependent_code(Object::null_array());
   return result.raw();
 }
 
 
 
 RawField* Field::Clone(const Class& new_owner) const {
   Field& clone = Field::Handle();
   clone ^= Object::Clone(*this, Heap::kOld);
   const Class& owner = Class::Handle(this->owner());
   const PatchClass& clone_owner =
       PatchClass::Handle(PatchClass::New(new_owner, owner));
   clone.set_owner(clone_owner);
   clone.set_dependent_code(Object::null_array());
   if (!clone.is_static()) {
     clone.SetOffset(0);
   }
   return clone.raw();
 }
 
 
 RawString* Field::UserVisibleName() const {
   const String& str = String::Handle(name());
   return IdentifierPrettyName(str);
 }
 
 
+intptr_t Field::guarded_list_length() const {
+  return Smi::Value(raw_ptr()->guarded_list_length_);
+}
+
+
+void Field::set_guarded_list_length(intptr_t list_length) const {
+  raw_ptr()->guarded_list_length_ = Smi::New(list_length);
+}
+
+
 const char* Field::ToCString() const {
   if (IsNull()) {
     return "Field::null";
   }
   const char* kF0 = is_static() ? " static" : "";
   const char* kF1 = is_final() ? " final" : "";
   const char* kF2 = is_const() ? " const" : "";
   const char* kFormat = "Field <%s.%s>:%s%s%s";
   const char* field_name = String::Handle(name()).ToCString();
   const Class& cls = Class::Handle(owner());
@@ skipping 172 matching lines @@
   if (list_length_unknown && list_length_changed && !force_invalidate) {
     // List length set for first time.
     set_guarded_list_length(list_length);
     return;
   }
 
   if (!list_length_changed && !force_invalidate) {
     // List length unchanged.
     return;
   }
-
   // Multiple list lengths assigned here, stop tracking length.
   set_guarded_list_length(Field::kNoFixedLength);
   DeoptimizeDependentCode();
 }
 
 
 void LiteralToken::set_literal(const String& literal) const {
   StorePointer(&raw_ptr()->literal_, literal.raw());
 }
 
@@ skipping 9337 matching lines @@
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   stream->OpenObject();
   stream->CloseObject();
 }
 
 
 }  // namespace dart