Speed-up Class.getSimpleName()

Bug: 303631821
Test: atest LibcoreBenchmarkTests:libcore.benchmark.ClassTest
Change-Id: I106aed4fe24b9138005c4928a7690d10c6df1d0a

4 files changed, 66 insertions, 11 deletions

diff --git a/runtime/mirror/string-inl.h b/runtime/mirror/string-inl.h
index 66e0ef0bdb..0d18b78044 100644
--- a/runtime/mirror/string-inl.h
+++ b/runtime/mirror/string-inl.h
@@ -67,6 +67,20 @@ int32_t String::FastIndexOf(MemoryType* chars, int32_t ch, int32_t start) {
   return -1;
 }
 
+template <typename MemoryType>
+int32_t String::LastIndexOf(MemoryType* chars, int32_t ch, int32_t from_index) {
+  DCHECK_LT(from_index, GetLength());
+  const MemoryType* start = chars;
+  const MemoryType* p = chars + from_index;
+  while (p >= start) {
+    if (*p == ch) {
+      return p - chars;
+    }
+    p--;
+  }
+  return -1;
+}
+
 inline int32_t String::ComputeHashCode() {
   uint32_t hash = IsCompressed()
       ? ComputeUtf16Hash(GetValueCompressed(), GetLength())
diff --git a/runtime/mirror/string.cc b/runtime/mirror/string.cc
index 839e01a045..2a26d50d79 100644
--- a/runtime/mirror/string.cc
+++ b/runtime/mirror/string.cc
@@ -37,10 +37,10 @@ namespace mirror {
 
 int32_t String::FastIndexOf(int32_t ch, int32_t start) {
   int32_t count = GetLength();
-  if (start < 0) {
+  if (start >= count) {
+    return -1;
+  } else if (start < 0) {
     start = 0;
-  } else if (start > count) {
-    start = count;
   }
   if (IsCompressed()) {
     return FastIndexOf<uint8_t>(GetValueCompressed(), ch, start);
@@ -49,6 +49,18 @@ int32_t String::FastIndexOf(int32_t ch, int32_t start) {
   }
 }
 
+int32_t String::LastIndexOf(int32_t ch) {
+  int32_t count = GetLength();
+  if (count == 0) {
+    return -1;
+  }
+  if (IsCompressed()) {
+    return LastIndexOf<uint8_t>(GetValueCompressed(), ch, count - 1);
+  } else {
+    return LastIndexOf<uint16_t>(GetValue(), ch, count - 1);
+  }
+}
+
 int32_t String::ComputeAndSetHashCode() {
   int32_t new_hash_code = ComputeHashCode();
   SetHashCode(new_hash_code);
diff --git a/runtime/mirror/string.h b/runtime/mirror/string.h
index 90eb09211c..c0f9b39b1f 100644
--- a/runtime/mirror/string.h
+++ b/runtime/mirror/string.h
@@ -215,6 +215,12 @@ class MANAGED String final : public Object {
   int32_t FastIndexOf(MemoryType* chars, int32_t ch, int32_t start)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  int32_t LastIndexOf(int32_t ch) REQUIRES_SHARED(Locks::mutator_lock_);
+
+  template <typename MemoryType>
+  int32_t LastIndexOf(MemoryType* chars, int32_t ch, int32_t from_index)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+
   int32_t CompareTo(ObjPtr<String> other) REQUIRES_SHARED(Locks::mutator_lock_);
 
   static ObjPtr<CharArray> ToCharArray(Handle<String> h_this, Thread* self)
diff --git a/runtime/native/java_lang_Class.cc b/runtime/native/java_lang_Class.cc
index 5e54f85b9d..83736668bb 100644
--- a/runtime/native/java_lang_Class.cc
+++ b/runtime/native/java_lang_Class.cc
@@ -681,22 +681,45 @@ static jint Class_getInnerClassFlags(JNIEnv* env, jobject javaThis, jint default
   return mirror::Class::GetInnerClassFlags(klass, defaultValue);
 }
 
-static jstring Class_getInnerClassName(JNIEnv* env, jobject javaThis) {
+static jstring Class_getSimpleNameNative(JNIEnv* env, jobject javaThis) {
   ScopedFastNativeObjectAccess soa(env);
-  StackHandleScope<1> hs(soa.Self());
+  StackHandleScope<3> hs(soa.Self());
   Handle<mirror::Class> klass(hs.NewHandle(DecodeClass(soa, javaThis)));
+  MutableHandle<mirror::String> h_name(hs.NewHandle<mirror::String>(nullptr));
+  MutableHandle<mirror::String> h_inner_name(hs.NewHandle<mirror::String>(nullptr));
   if (klass->IsObsoleteObject()) {
     ThrowRuntimeException("Obsolete Object!");
     return nullptr;
   }
-  if (klass->IsProxyClass() || klass->GetDexCache() == nullptr) {
-    return nullptr;
+  if (!klass->IsProxyClass() && klass->GetDexCache() != nullptr) {
+    ObjPtr<mirror::String> class_name = nullptr;
+    if (annotations::GetInnerClass(klass, &class_name)) {
+      if (class_name == nullptr) {  // Anonymous class
+        gc::AllocatorType allocator_type = Runtime::Current()->GetHeap()->GetCurrentAllocator();
+        return soa.AddLocalReference<jstring>(
+            mirror::String::AllocEmptyString(soa.Self(), allocator_type));
+      }
+      h_inner_name.Assign(class_name);
+      if (annotations::GetDeclaringClass(klass) != nullptr ||   // member class
+          annotations::GetEnclosingMethod(klass) != nullptr) {  // local class
+        return soa.AddLocalReference<jstring>(h_inner_name.Get());
+      }
+    }
   }
-  ObjPtr<mirror::String> class_name = nullptr;
-  if (!annotations::GetInnerClass(klass, &class_name)) {
+
+  h_name.Assign(mirror::Class::ComputeName(klass));
+  if (h_name == nullptr) {
     return nullptr;
   }
-  return soa.AddLocalReference<jstring>(class_name);
+  int32_t dot_index = h_name->LastIndexOf('.');
+  if (dot_index < 0) {
+    return soa.AddLocalReference<jstring>(h_name.Get());
+  }
+  int32_t start_index = dot_index + 1;
+  int32_t length = h_name->GetLength() - start_index;
+  gc::AllocatorType allocator_type = Runtime::Current()->GetHeap()->GetCurrentAllocator();
+  return soa.AddLocalReference<jstring>(
+      mirror::String::AllocFromString(soa.Self(), length, h_name, start_index, allocator_type));
 }
 
 static jobjectArray Class_getSignatureAnnotation(JNIEnv* env, jobject javaThis) {
@@ -971,7 +994,6 @@ static JNINativeMethod gMethods[] = {
   FAST_NATIVE_METHOD(Class, getEnclosingConstructorNative, "()Ljava/lang/reflect/Constructor;"),
   FAST_NATIVE_METHOD(Class, getEnclosingMethodNative, "()Ljava/lang/reflect/Method;"),
   FAST_NATIVE_METHOD(Class, getInnerClassFlags, "(I)I"),
-  FAST_NATIVE_METHOD(Class, getInnerClassName, "()Ljava/lang/String;"),
   FAST_NATIVE_METHOD(Class, getInterfacesInternal, "()[Ljava/lang/Class;"),
   FAST_NATIVE_METHOD(Class, getPrimitiveClass, "(Ljava/lang/String;)Ljava/lang/Class;"),
   FAST_NATIVE_METHOD(Class, getNameNative, "()Ljava/lang/String;"),
@@ -981,6 +1003,7 @@ static JNINativeMethod gMethods[] = {
   FAST_NATIVE_METHOD(Class, getPublicDeclaredFields, "()[Ljava/lang/reflect/Field;"),
   FAST_NATIVE_METHOD(Class, getRecordAnnotationElement, "(Ljava/lang/String;Ljava/lang/Class;)[Ljava/lang/Object;"),
   FAST_NATIVE_METHOD(Class, getSignatureAnnotation, "()[Ljava/lang/String;"),
+  FAST_NATIVE_METHOD(Class, getSimpleNameNative, "()Ljava/lang/String;"),
   FAST_NATIVE_METHOD(Class, isAnonymousClass, "()Z"),
   FAST_NATIVE_METHOD(Class, isDeclaredAnnotationPresent, "(Ljava/lang/Class;)Z"),
   FAST_NATIVE_METHOD(Class, isRecord0, "()Z"),