8059677: Thread.getName() instantiates Strings

Reviewed-by: coleenp, dholmes, sla

agent/src/share/classes/sun/jvm/hotspot/oops/OopUtilities.java

 /*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -219,7 +219,7 @@ public class OopUtilities implements /* imports */ JVMTIThreadState {
     if (threadNameField == null) {
       SystemDictionary sysDict = VM.getVM().getSystemDictionary();
       InstanceKlass k = sysDict.getThreadKlass();
-      threadNameField  = (OopField) k.findField("name", "[C");
+      threadNameField  = (OopField) k.findField("name", "Ljava/lang/String;");
       threadGroupField = (OopField) k.findField("group", "Ljava/lang/ThreadGroup;");
       threadEETopField = (LongField) k.findField("eetop", "J");
       threadTIDField = (LongField) k.findField("tid", "J");
@@ -258,7 +258,7 @@ public class OopUtilities implements /* imports */ JVMTIThreadState {
 
   public static String threadOopGetName(Oop threadOop) {
     initThreadFields();
-    return charArrayToString((TypeArray) threadNameField.getValue(threadOop));
+    return stringOopToString(threadNameField.getValue(threadOop));
   }
 
   /** May return null if, e.g., thread was not started */

src/share/vm/classfile/javaClasses.cpp

 /*
- * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -936,7 +936,7 @@ void java_lang_Thread::compute_offsets() {
   assert(_group_offset == 0, "offsets should be initialized only once");
 
   Klass* k = SystemDictionary::Thread_klass();
-  compute_offset(_name_offset,      k, vmSymbols::name_name(),      vmSymbols::char_array_signature());
+  compute_offset(_name_offset,      k, vmSymbols::name_name(),      vmSymbols::string_signature());
   compute_offset(_group_offset,     k, vmSymbols::group_name(),     vmSymbols::threadgroup_signature());
   compute_offset(_contextClassLoader_offset, k, vmSymbols::contextClassLoader_name(), vmSymbols::classloader_signature());
   compute_offset(_inheritedAccessControlContext_offset, k, vmSymbols::inheritedAccessControlContext_name(), vmSymbols::accesscontrolcontext_signature());
@@ -966,15 +966,12 @@ void java_lang_Thread::set_thread(oop java_thread, JavaThread* thread) {
 }
 
 
-typeArrayOop java_lang_Thread::name(oop java_thread) {
-  oop name = java_thread->obj_field(_name_offset);
-  assert(name == NULL || (name->is_typeArray() && TypeArrayKlass::cast(name->klass())->element_type() == T_CHAR), "just checking");
-  return typeArrayOop(name);
+oop java_lang_Thread::name(oop java_thread) {
+  return java_thread->obj_field(_name_offset);
 }
 
 
-void java_lang_Thread::set_name(oop java_thread, typeArrayOop name) {
-  assert(java_thread->obj_field(_name_offset) == NULL, "name should be NULL");
+void java_lang_Thread::set_name(oop java_thread, oop name) {
   java_thread->obj_field_put(_name_offset, name);
 }
 

src/share/vm/classfile/javaClasses.hpp

 /*
- * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -343,8 +343,8 @@ class java_lang_Thread : AllStatic {
   // Set JavaThread for instance
   static void set_thread(oop java_thread, JavaThread* thread);
   // Name
-  static typeArrayOop name(oop java_thread);
-  static void set_name(oop java_thread, typeArrayOop name);
+  static oop name(oop java_thread);
+  static void set_name(oop java_thread, oop name);
   // Priority
   static ThreadPriority priority(oop java_thread);
   static void set_priority(oop java_thread, ThreadPriority priority);

src/share/vm/prims/jvmtiEnv.cpp

 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -946,7 +946,7 @@ JvmtiEnv::GetThreadInfo(jthread thread, jvmtiThreadInfo* info_ptr) {
     return JVMTI_ERROR_INVALID_THREAD;
 
   Handle thread_obj(current_thread, thread_oop);
-  typeArrayHandle    name;
+  Handle name;
   ThreadPriority priority;
   Handle     thread_group;
   Handle context_class_loader;
@@ -954,7 +954,7 @@ JvmtiEnv::GetThreadInfo(jthread thread, jvmtiThreadInfo* info_ptr) {
 
   { MutexLocker mu(Threads_lock);
 
-    name = typeArrayHandle(current_thread, java_lang_Thread::name(thread_obj()));
+    name = Handle(current_thread, java_lang_Thread::name(thread_obj()));
     priority = java_lang_Thread::priority(thread_obj());
     thread_group = Handle(current_thread, java_lang_Thread::threadGroup(thread_obj()));
     is_daemon = java_lang_Thread::is_daemon(thread_obj());
@@ -965,7 +965,7 @@ JvmtiEnv::GetThreadInfo(jthread thread, jvmtiThreadInfo* info_ptr) {
   { const char *n;
 
     if (name() != NULL) {
-      n = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+      n = java_lang_String::as_utf8_string(name());
     } else {
       n = UNICODE::as_utf8(NULL, 0);
     }

src/share/vm/prims/jvmtiTrace.cpp

 /*
- * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -266,11 +266,11 @@ const char *JvmtiTrace::safe_get_thread_name(Thread *thread) {
   if (threadObj == NULL) {
     return "NULL";
   }
-  typeArrayOop name = java_lang_Thread::name(threadObj);
+  oop name = java_lang_Thread::name(threadObj);
   if (name == NULL) {
     return "<NOT FILLED IN>";
   }
-  return UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+  return java_lang_String::as_utf8_string(name);
 }
 
 

src/share/vm/runtime/thread.cpp

 /*
- * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -2926,13 +2926,13 @@ const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
   const char* name_str;
   oop thread_obj = threadObj();
   if (thread_obj != NULL) {
-    typeArrayOop name = java_lang_Thread::name(thread_obj);
+    oop name = java_lang_Thread::name(thread_obj);
     if (name != NULL) {
       if (buf == NULL) {
-        name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
+        name_str = java_lang_String::as_utf8_string(name);
       }
       else {
-        name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
+        name_str = java_lang_String::as_utf8_string(name, buf, buflen);
       }
     }
     else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306