ART: Check for duplicate classes when loading oat files

Oat files are usually produced standalone, and the compilers take
advantage of any information they get. It is thus possible that
when compile-time and runtime class-path are not the same, classes
are resolved differently and optimized code is incorrect.

This is a very conservative check, scanning the complete class tables
of dex files. In case any duplicate class is found, the new oat file
will be rejected and the original dex files will be used in interpreted
mode.

A possible refinement to this is actual tracking of the compile-time
class-path instead. That is however significantly complicated by the
DexFile API and the non-standard uses it allows.

An alternative for both optimized code and correct resolution is
native multidex. Apps should switch to multidex and benefit from
the optimization as well as the shift of all compile time to install
time. Split APKs are currently compiled separately, but it is a goal
to change that install flow to simulated multidex.

Change-Id: Ib9e0db5091e060e3bb2c0e5e6c007430becbfc21

1 files changed, 32 insertions, 0 deletions

diff --git a/test/138-duplicate-classes-check2/build b/test/138-duplicate-classes-check2/build
new file mode 100755
index 0000000..abcbbb8
--- /dev/null
+++ b/test/138-duplicate-classes-check2/build
@@ -0,0 +1,32 @@
+#!/bin/bash
+#
+# Copyright (C) 2015 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.
+
+# Stop if something fails.
+set -e
+
+mkdir classes
+${JAVAC} -d classes `find src -name '*.java'`
+
+mkdir classes-ex
+${JAVAC} -d classes-ex `find src-ex -name '*.java'`
+rm classes-ex/A.class
+
+if [ ${NEED_DEX} = "true" ]; then
+  ${DX} -JXmx256m --debug --dex --dump-to=classes.lst --output=classes.dex --dump-width=1000 classes
+  zip $TEST_NAME.jar classes.dex
+  ${DX} -JXmx256m --debug --dex --dump-to=classes-ex.lst --output=classes.dex --dump-width=1000 classes-ex
+  zip ${TEST_NAME}-ex.jar classes.dex
+fi