Fix crash that happens when we send an object whose type is in a defer

runtime/vm/snapshot.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/snapshot.h"
 
 #include "platform/assert.h"
 #include "vm/bootstrap.h"
 #include "vm/class_finalizer.h"
+#include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/heap.h"
 #include "vm/lockers.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot_ids.h"
 #include "vm/symbols.h"
 #include "vm/verified_memory.h"
 #include "vm/version.h"
@@ skipping 196 matching lines @@
   ASSERT((class_header & kSmiTagMask) != kSmiTag);
   ASSERT(!IsVMIsolateObject(class_header) ||
          !IsSingletonClassId(GetVMIsolateObjectId(class_header)));
   ASSERT((SerializedHeaderTag::decode(class_header) != kObjectId) ||
          !IsObjectStoreClassId(SerializedHeaderData::decode(class_header)));
   Class& cls = Class::ZoneHandle(isolate(), Class::null());
   AddBackRef(object_id, &cls, kIsDeserialized);
   // Read the library/class information and lookup the class.
   str_ ^= ReadObjectImpl(class_header);
   library_ = Library::LookupLibrary(str_);
-  ASSERT(!library_.IsNull());
+  if (library_.IsNull() || !library_.Loaded()) {
+    SetReadException("Invalid object found in message.");
+  }
   str_ ^= ReadObjectImpl();
   cls = library_.LookupClass(str_);
+  if (cls.IsNull()) {
+    SetReadException("Invalid object found in message.");
+  }
   cls.EnsureIsFinalized(isolate());
-  ASSERT(!cls.IsNull());
   return cls.raw();
 }
 
 
 RawObject* SnapshotReader::ReadObjectImpl() {
   int64_t value = Read<int64_t>();
   if ((value & kSmiTagMask) == kSmiTag) {
     return NewInteger(value);
   }
   ASSERT((value <= kIntptrMax) && (value >= kIntptrMin));
   return ReadObjectImpl(static_cast<intptr_t>(value));
 }
 
 
 intptr_t SnapshotReader::NextAvailableObjectId() const {
   return backward_references_.length() + kMaxPredefinedObjectIds;
 }
 
 
+void SnapshotReader::SetReadException(const char* msg) {
+  Isolate* isolate = Isolate::Current();
+  const String& error_str = String::Handle(isolate, String::New(msg));
+  const Array& args = Array::Handle(isolate, Array::New(1));
+  args.SetAt(0, error_str);
+  Object& result = Object::Handle(isolate);
+  const Library& library = Library::Handle(isolate, Library::CoreLibrary());
+  result = DartLibraryCalls::InstanceCreate(library,
+                                            Symbols::ArgumentError(),
+                                            Symbols::Dot(),
+                                            args);
+  const Stacktrace& stacktrace = Stacktrace::Handle(isolate);
+  const UnhandledException& error = UnhandledException::Handle(
+      isolate, UnhandledException::New(Instance::Cast(result), stacktrace));
+  isolate->long_jump_base()->Jump(1, error);
+}
+
+
 RawObject* SnapshotReader::ReadObjectImpl(intptr_t header_value) {
   if (IsVMIsolateObject(header_value)) {
     return ReadVMIsolateObject(header_value);
   } else {
     if (SerializedHeaderTag::decode(header_value) == kObjectId) {
       return ReadIndexedObject(SerializedHeaderData::decode(header_value));
     }
     ASSERT(SerializedHeaderTag::decode(header_value) == kInlined);
     intptr_t object_id = SerializedHeaderData::decode(header_value);
     if (object_id == kOmittedObjectId) {
@@ skipping 1534 matching lines @@
     NoGCScope no_gc;
     WriteObject(obj.raw());
     UnmarkAll();
   } else {
     ThrowException(exception_type(), exception_msg());
   }
 }
 
 
 }  // namespace dart