Make sure that const-class linkage is preserved.

After calling loadClass() on the initiating loader, insert
the Class to the ClassTable. Check that the returned class
has the correct name and that the ClassTable does not yet
contain a different Class for the same name. If either check
fails, follow the RI behavior for parallel capable class
loaders, i.e. throw NoClassDefFoundError for name mismatch
(with more descriptive message than RI) or return the Class
already present in the ClassTable. This ensures that the
const-class instruction for a given name always gives the
same result as the first time it succeeded for the same
initiating loader, even for non-well-behaved loader.

Inserting the Class to the ClassTable is also a necessary
step for changing to hash-based dex cache type array when
the DexCache will not necessarily keep the Class and
therefore the defining loader alive while the initiating
loader stays alive, so the ClassTable entry is necessary
to keep the dependecy.

Add tests that a const-class instruction always returns the
same Class<?> as it returned the first time, i.e. when it
was "linked", even for class loaders that are not
well-behaved, even if the dex cache type array is cleared.
Also test the edge cases, i.e. NoClassDefFoundError and
returning old entry from ClassTable when already inserted
by another thread.

Bug: 30627598
Test: 626-const-class-linking
Test: m test-art-host
Change-Id: Ie9b721464b4e9a5dcce8df8095548e983bba1fe8

1 files changed, 18 insertions, 0 deletions

diff --git a/test/626-const-class-linking/src-multidex/Test.java b/test/626-const-class-linking/src-multidex/Test.java
new file mode 100644
index 0000000000..1b0cc2a791
--- /dev/null
+++ b/test/626-const-class-linking/src-multidex/Test.java
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+public class Test {
+}