Use class def index from java.lang.Class.

Bug: 10244719
This removes the computation of the dex file index, when necessary this is
computed by searching the dex file. Its only necessary in
dalvik.system.DexFile.defineClassNative and DexFile::FindInClassPath, the
latter not showing up significantly in profiling with this change.

(cherry-picked from 8b2c0b9abc3f520495f4387ea040132ba85cae69)
Change-Id: I20c73a3b17d86286428ab0fd21bc13f51f36c85c

1 files changed, 56 insertions, 0 deletions

diff --git a/runtime/native/java_lang_DexCache.cc b/runtime/native/java_lang_DexCache.cc
new file mode 100644
index 0000000000..f8eeb2906e
--- /dev/null
+++ b/runtime/native/java_lang_DexCache.cc
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#include "dex_file.h"
+#include "mirror/dex_cache.h"
+#include "mirror/object-inl.h"
+#include "scoped_thread_state_change.h"
+#include "well_known_classes.h"
+
+namespace art {
+
+static jobject DexCache_getDexNative(JNIEnv* env, jobject javaDexCache) {
+  ScopedObjectAccess soa(env);
+  mirror::DexCache* dex_cache = soa.Decode<mirror::DexCache*>(javaDexCache);
+  // Should only be called while holding the lock on the dex cache.
+  DCHECK_EQ(dex_cache->GetThinLockId(), soa.Self()->GetThinLockId());
+  const DexFile* dex_file = dex_cache->GetDexFile();
+  if (dex_file == NULL) {
+    return NULL;
+  }
+  void* address = const_cast<void*>(reinterpret_cast<const void*>(dex_file->Begin()));
+  jobject byte_buffer = env->NewDirectByteBuffer(address, dex_file->Size());
+  if (byte_buffer == NULL) {
+    DCHECK(soa.Self()->IsExceptionPending());
+    return NULL;
+  }
+
+  jvalue args[1];
+  args[0].l = byte_buffer;
+  return env->CallStaticObjectMethodA(WellKnownClasses::com_android_dex_Dex,
+                                      WellKnownClasses::com_android_dex_Dex_create,
+                                      args);
+}
+
+static JNINativeMethod gMethods[] = {
+  NATIVE_METHOD(DexCache, getDexNative, "()Lcom/android/dex/Dex;"),
+};
+
+void register_java_lang_DexCache(JNIEnv* env) {
+  REGISTER_NATIVE_METHODS("java/lang/DexCache");
+}
+
+}  // namespace art