Avoid std::string allocations for finding an array class.

Introduce ClassLinker::FindArrayClass which performs an array class lookup
given the element/component class. This has a 16 element cache of recently
looked up arrays.
Pass the current thread to ClassLinker Find .. Class routines to avoid calls
to Thread::Current().
Avoid some uses of FindClass in the debugger where WellKnownClasses is a
faster and more compacting GC friendly alternative.

Change-Id: I60e231820b349543a7edb3ceb9cf1ce92db3c843

1 files changed, 4 insertions, 2 deletions

diff --git a/runtime/native/java_lang_Class.cc b/runtime/native/java_lang_Class.cc
index 3e3f608c89..8bf36e7e37 100644
--- a/runtime/native/java_lang_Class.cc
+++ b/runtime/native/java_lang_Class.cc
@@ -43,7 +43,8 @@ static mirror::Class* DecodeClass(const ScopedFastNativeObjectAccess& soa, jobje
 }
 
 // "name" is in "binary name" format, e.g. "dalvik.system.Debug$1".
-static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean initialize, jobject javaLoader) {
+static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean initialize,
+                                 jobject javaLoader) {
   ScopedObjectAccess soa(env);
   ScopedUtfChars name(env, javaName);
   if (name.c_str() == nullptr) {
@@ -64,7 +65,8 @@ static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean
   SirtRef<mirror::ClassLoader> class_loader(soa.Self(),
                                             soa.Decode<mirror::ClassLoader*>(javaLoader));
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
-  SirtRef<mirror::Class> c(soa.Self(), class_linker->FindClass(descriptor.c_str(), class_loader));
+  SirtRef<mirror::Class> c(soa.Self(), class_linker->FindClass(soa.Self(), descriptor.c_str(),
+                                                               class_loader));
   if (c.get() == nullptr) {
     ScopedLocalRef<jthrowable> cause(env, env->ExceptionOccurred());
     env->ExceptionClear();