ART: Move Class::Status to ClassStatus

Move the enum to its own file to lower include burden on others.
This is an intentionally small and localized change. Users will
be cleaned up in a follow-up.

Bug: 63467744
Bug: 65318848
Test: m test-art-host
Change-Id: If3bfe6953973e24623e78a2a8dcc69b50117aa3c

1 files changed, 96 insertions, 0 deletions

diff --git a/runtime/class_status.h b/runtime/class_status.h
new file mode 100644
index 0000000000..0877e68818
--- /dev/null
+++ b/runtime/class_status.h
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_CLASS_STATUS_H_
+#define ART_RUNTIME_CLASS_STATUS_H_
+
+#include <iosfwd>
+
+namespace art {
+
+// Class Status
+//
+// kStatusRetired: Class that's temporarily used till class linking time
+// has its (vtable) size figured out and has been cloned to one with the
+// right size which will be the one used later. The old one is retired and
+// will be gc'ed once all refs to the class point to the newly
+// cloned version.
+//
+// kStatusErrorUnresolved, kStatusErrorResolved: Class is erroneous. We need
+// to distinguish between classes that have been resolved and classes that
+// have not. This is important because the const-class instruction needs to
+// return a previously resolved class even if its subsequent initialization
+// failed. We also need this to decide whether to wrap a previous
+// initialization failure in ClassDefNotFound error or not.
+//
+// kStatusNotReady: If a Class cannot be found in the class table by
+// FindClass, it allocates an new one with AllocClass in the
+// kStatusNotReady and calls LoadClass. Note if it does find a
+// class, it may not be kStatusResolved and it will try to push it
+// forward toward kStatusResolved.
+//
+// kStatusIdx: LoadClass populates with Class with information from
+// the DexFile, moving the status to kStatusIdx, indicating that the
+// Class value in super_class_ has not been populated. The new Class
+// can then be inserted into the classes table.
+//
+// kStatusLoaded: After taking a lock on Class, the ClassLinker will
+// attempt to move a kStatusIdx class forward to kStatusLoaded by
+// using ResolveClass to initialize the super_class_ and ensuring the
+// interfaces are resolved.
+//
+// kStatusResolving: Class is just cloned with the right size from
+// temporary class that's acting as a placeholder for linking. The old
+// class will be retired. New class is set to this status first before
+// moving on to being resolved.
+//
+// kStatusResolved: Still holding the lock on Class, the ClassLinker
+// shows linking is complete and fields of the Class populated by making
+// it kStatusResolved. Java allows circularities of the form where a super
+// class has a field that is of the type of the sub class. We need to be able
+// to fully resolve super classes while resolving types for fields.
+//
+// kStatusRetryVerificationAtRuntime: The verifier sets a class to
+// this state if it encounters a soft failure at compile time. This
+// often happens when there are unresolved classes in other dex
+// files, and this status marks a class as needing to be verified
+// again at runtime.
+//
+// TODO: Explain the other states
+enum ClassStatus {
+  kStatusRetired = -3,  // Retired, should not be used. Use the newly cloned one instead.
+  kStatusErrorResolved = -2,
+  kStatusErrorUnresolved = -1,
+  kStatusNotReady = 0,
+  kStatusIdx = 1,  // Loaded, DEX idx in super_class_type_idx_ and interfaces_type_idx_.
+  kStatusLoaded = 2,  // DEX idx values resolved.
+  kStatusResolving = 3,  // Just cloned from temporary class object.
+  kStatusResolved = 4,  // Part of linking.
+  kStatusVerifying = 5,  // In the process of being verified.
+  kStatusRetryVerificationAtRuntime = 6,  // Compile time verification failed, retry at runtime.
+  kStatusVerifyingAtRuntime = 7,  // Retrying verification at runtime.
+  kStatusVerified = 8,  // Logically part of linking; done pre-init.
+  kStatusSuperclassValidated = 9,  // Superclass validation part of init done.
+  kStatusInitializing = 10,  // Class init in progress.
+  kStatusInitialized = 11,  // Ready to go.
+  kStatusMax = 12,
+};
+
+std::ostream& operator<<(std::ostream& os, const ClassStatus& rhs);
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_CLASS_STATUS_H_