--- a/hotspot/src/share/vm/classfile/javaClasses.cpp	Wed Jul 05 22:55:08 2017 +0200
+++ b/hotspot/src/share/vm/classfile/javaClasses.cpp	Fri Feb 24 12:41:26 2017 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, 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
@@ -514,11 +514,10 @@
   return result;
 }
 
-Symbol* java_lang_String::as_symbol(Handle java_string, TRAPS) {
-  oop          obj    = java_string();
-  typeArrayOop value  = java_lang_String::value(obj);
-  int          length = java_lang_String::length(obj);
-  bool      is_latin1 = java_lang_String::is_latin1(obj);
+Symbol* java_lang_String::as_symbol(oop java_string, TRAPS) {
+  typeArrayOop value  = java_lang_String::value(java_string);
+  int          length = java_lang_String::length(java_string);
+  bool      is_latin1 = java_lang_String::is_latin1(java_string);
   if (!is_latin1) {
     jchar* base = (length == 0) ? NULL : value->char_at_addr(0);
     Symbol* sym = SymbolTable::lookup_unicode(base, length, THREAD);
@@ -753,7 +752,7 @@
       }
     }
   }
-  create_mirror(k, Handle(NULL), Handle(NULL), Handle(NULL), CHECK);
+  create_mirror(k, Handle(), Handle(), Handle(), CHECK);
 }
 
 void java_lang_Class::initialize_mirror_fields(KlassHandle k,
@@ -828,7 +827,8 @@
   // the mirror.
   if (SystemDictionary::Class_klass_loaded()) {
     // Allocate mirror (java.lang.Class instance)
-    Handle mirror = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->allocate_instance(k, CHECK);
+    oop mirror_oop = InstanceMirrorKlass::cast(SystemDictionary::Class_klass())->allocate_instance(k, CHECK);
+    Handle mirror(THREAD, mirror_oop);
 
     // Setup indirection from mirror->klass
     if (!k.is_null()) {
@@ -842,7 +842,7 @@
 
     // It might also have a component mirror.  This mirror must already exist.
     if (k->is_array_klass()) {
-      Handle comp_mirror;
+      oop comp_mirror;
       if (k->is_typeArray_klass()) {
         BasicType type = TypeArrayKlass::cast(k())->element_type();
         comp_mirror = Universe::java_mirror(type);
@@ -852,12 +852,12 @@
         assert(element_klass != NULL, "Must have an element klass");
         comp_mirror = element_klass->java_mirror();
       }
-      assert(comp_mirror.not_null(), "must have a mirror");
+      assert(comp_mirror != NULL, "must have a mirror");
 
       // Two-way link between the array klass and its component mirror:
       // (array_klass) k -> mirror -> component_mirror -> array_klass -> k
-      set_component_mirror(mirror(), comp_mirror());
-      set_array_klass(comp_mirror(), k());
+      set_component_mirror(mirror(), comp_mirror);
+      set_array_klass(comp_mirror, k());
     } else {
       assert(k->is_instance_klass(), "Must be");
 
@@ -1518,7 +1518,7 @@
   throwable->int_field_put(depth_offset, value);
 }
 
-oop java_lang_Throwable::message(Handle throwable) {
+oop java_lang_Throwable::message(oop throwable) {
   return throwable->obj_field(detailMessage_offset);
 }
 
@@ -1547,7 +1547,7 @@
 }
 
 
-void java_lang_Throwable::print(Handle throwable, outputStream* st) {
+void java_lang_Throwable::print(oop throwable, outputStream* st) {
   ResourceMark rm;
   Klass* k = throwable->klass();
   assert(k != NULL, "just checking");
@@ -1578,7 +1578,7 @@
   typeArrayOop    _methods;
   typeArrayOop    _bcis;
   objArrayOop     _mirrors;
-  typeArrayOop    _cprefs; // needed to insulate method name against redefinition
+  typeArrayOop    _names; // needed to insulate method name against redefinition
   int             _index;
   NoSafepointVerifier _nsv;
 
@@ -1586,7 +1586,7 @@
     trace_methods_offset = java_lang_Throwable::trace_methods_offset,
     trace_bcis_offset    = java_lang_Throwable::trace_bcis_offset,
     trace_mirrors_offset = java_lang_Throwable::trace_mirrors_offset,
-    trace_cprefs_offset  = java_lang_Throwable::trace_cprefs_offset,
+    trace_names_offset   = java_lang_Throwable::trace_names_offset,
     trace_next_offset    = java_lang_Throwable::trace_next_offset,
     trace_size           = java_lang_Throwable::trace_size,
     trace_chunk_size     = java_lang_Throwable::trace_chunk_size
@@ -1608,32 +1608,34 @@
     assert(mirrors != NULL, "mirror array should be initialized in backtrace");
     return mirrors;
   }
-  static typeArrayOop get_cprefs(objArrayHandle chunk) {
-    typeArrayOop cprefs = typeArrayOop(chunk->obj_at(trace_cprefs_offset));
-    assert(cprefs != NULL, "cprefs array should be initialized in backtrace");
-    return cprefs;
+  static typeArrayOop get_names(objArrayHandle chunk) {
+    typeArrayOop names = typeArrayOop(chunk->obj_at(trace_names_offset));
+    assert(names != NULL, "names array should be initialized in backtrace");
+    return names;
   }
 
  public:
 
   // constructor for new backtrace
-  BacktraceBuilder(TRAPS): _methods(NULL), _bcis(NULL), _head(NULL), _mirrors(NULL), _cprefs(NULL) {
+  BacktraceBuilder(TRAPS): _methods(NULL), _bcis(NULL), _head(NULL), _mirrors(NULL), _names(NULL) {
     expand(CHECK);
-    _backtrace = _head;
+    _backtrace = Handle(THREAD, _head);
     _index = 0;
   }
 
-  BacktraceBuilder(objArrayHandle backtrace) {
+  BacktraceBuilder(Thread* thread, objArrayHandle backtrace) {
     _methods = get_methods(backtrace);
     _bcis = get_bcis(backtrace);
     _mirrors = get_mirrors(backtrace);
-    _cprefs = get_cprefs(backtrace);
+    _names = get_names(backtrace);
     assert(_methods->length() == _bcis->length() &&
-           _methods->length() == _mirrors->length(),
+           _methods->length() == _mirrors->length() &&
+           _mirrors->length() == _names->length(),
            "method and source information arrays should match");
 
     // head is the preallocated backtrace
-    _backtrace = _head = backtrace();
+    _head = backtrace();
+    _backtrace = Handle(thread, _head);
     _index = 0;
   }
 
@@ -1653,8 +1655,8 @@
     objArrayOop mirrors = oopFactory::new_objectArray(trace_chunk_size, CHECK);
     objArrayHandle new_mirrors(THREAD, mirrors);
 
-    typeArrayOop cprefs = oopFactory::new_shortArray(trace_chunk_size, CHECK);
-    typeArrayHandle new_cprefs(THREAD, cprefs);
+    typeArrayOop names = oopFactory::new_symbolArray(trace_chunk_size, CHECK);
+    typeArrayHandle new_names(THREAD, names);
 
     if (!old_head.is_null()) {
       old_head->obj_at_put(trace_next_offset, new_head());
@@ -1662,13 +1664,13 @@
     new_head->obj_at_put(trace_methods_offset, new_methods());
     new_head->obj_at_put(trace_bcis_offset, new_bcis());
     new_head->obj_at_put(trace_mirrors_offset, new_mirrors());
-    new_head->obj_at_put(trace_cprefs_offset, new_cprefs());
+    new_head->obj_at_put(trace_names_offset, new_names());
 
     _head    = new_head();
     _methods = new_methods();
     _bcis = new_bcis();
     _mirrors = new_mirrors();
-    _cprefs  = new_cprefs();
+    _names  = new_names();
     _index = 0;
   }
 
@@ -1690,7 +1692,11 @@
 
     _methods->short_at_put(_index, method->orig_method_idnum());
     _bcis->int_at_put(_index, Backtrace::merge_bci_and_version(bci, method->constants()->version()));
-    _cprefs->short_at_put(_index, method->name_index());
+
+    // Note:this doesn't leak symbols because the mirror in the backtrace keeps the
+    // klass owning the symbols alive so their refcounts aren't decremented.
+    Symbol* name = method->name();
+    _names->symbol_at_put(_index, name);
 
     // We need to save the mirrors in the backtrace to keep the class
     // from being unloaded while we still have this stack trace.
@@ -1705,10 +1711,10 @@
   int _method_id;
   int _bci;
   int _version;
-  int _cpref;
+  Symbol* _name;
   Handle _mirror;
-  BacktraceElement(Handle mirror, int mid, int version, int bci, int cpref) :
-                   _mirror(mirror), _method_id(mid), _version(version), _bci(bci), _cpref(cpref) {}
+  BacktraceElement(Handle mirror, int mid, int version, int bci, Symbol* name) :
+                   _mirror(mirror), _method_id(mid), _version(version), _bci(bci), _name(name) {}
 };
 
 class BacktraceIterator : public StackObj {
@@ -1717,7 +1723,7 @@
   objArrayHandle  _mirrors;
   typeArrayHandle _methods;
   typeArrayHandle _bcis;
-  typeArrayHandle _cprefs;
+  typeArrayHandle _names;
 
   void init(objArrayHandle result, Thread* thread) {
     // Get method id, bci, version and mirror from chunk
@@ -1726,7 +1732,7 @@
       _methods = typeArrayHandle(thread, BacktraceBuilder::get_methods(_result));
       _bcis = typeArrayHandle(thread, BacktraceBuilder::get_bcis(_result));
       _mirrors = objArrayHandle(thread, BacktraceBuilder::get_mirrors(_result));
-      _cprefs = typeArrayHandle(thread, BacktraceBuilder::get_cprefs(_result));
+      _names = typeArrayHandle(thread, BacktraceBuilder::get_names(_result));
       _index = 0;
     }
   }
@@ -1741,7 +1747,7 @@
                         _methods->short_at(_index),
                         Backtrace::version_at(_bcis->int_at(_index)),
                         Backtrace::bci_at(_bcis->int_at(_index)),
-                        _cprefs->short_at(_index));
+                        _names->symbol_at(_index));
     _index++;
 
     if (_index >= java_lang_Throwable::trace_chunk_size) {
@@ -1761,7 +1767,7 @@
 
 // Print stack trace element to resource allocated buffer
 static void print_stack_element_to_stream(outputStream* st, Handle mirror, int method_id,
-                                          int version, int bci, int cpref) {
+                                          int version, int bci, Symbol* name) {
   ResourceMark rm;
 
   // Get strings and string lengths
@@ -1769,11 +1775,7 @@
   const char* klass_name  = holder->external_name();
   int buf_len = (int)strlen(klass_name);
 
-  Method* method = holder->method_with_orig_idnum(method_id, version);
-
-  // The method can be NULL if the requested class version is gone
-  Symbol* sym = (method != NULL) ? method->name() : holder->constants()->symbol_at(cpref);
-  char* method_name = sym->as_C_string();
+  char* method_name = name->as_C_string();
   buf_len += (int)strlen(method_name);
 
   char* source_file_name = NULL;
@@ -1809,6 +1811,8 @@
     }
   }
 
+  // The method can be NULL if the requested class version is gone
+  Method* method = holder->method_with_orig_idnum(method_id, version);
   if (!version_matches(method, version)) {
     strcat(buf, "Redefined)");
   } else {
@@ -1837,11 +1841,10 @@
 }
 
 void java_lang_Throwable::print_stack_element(outputStream *st, const methodHandle& method, int bci) {
-  Handle mirror = method->method_holder()->java_mirror();
+  Handle mirror (Thread::current(),  method->method_holder()->java_mirror());
   int method_id = method->orig_method_idnum();
   int version = method->constants()->version();
-  int cpref = method->name_index();
-  print_stack_element_to_stream(st, mirror, method_id, version, bci, cpref);
+  print_stack_element_to_stream(st, mirror, method_id, version, bci, method->name());
 }
 
 /**
@@ -1850,7 +1853,7 @@
  */
 void java_lang_Throwable::print_stack_trace(Handle throwable, outputStream* st) {
   // First, print the message.
-  print(throwable, st);
+  print(throwable(), st);
   st->cr();
 
   // Now print the stack trace.
@@ -1865,7 +1868,7 @@
 
     while (iter.repeat()) {
       BacktraceElement bte = iter.next(THREAD);
-      print_stack_element_to_stream(st, bte._mirror, bte._method_id, bte._version, bte._bci, bte._cpref);
+      print_stack_element_to_stream(st, bte._mirror, bte._method_id, bte._version, bte._bci, bte._name);
     }
     {
       // Call getCause() which doesn't necessarily return the _cause field.
@@ -1885,7 +1888,7 @@
         throwable = Handle(THREAD, (oop) cause.get_jobject());
         if (throwable.not_null()) {
           st->print("Caused by: ");
-          print(throwable, st);
+          print(throwable(), st);
           st->cr();
         }
       }
@@ -2089,7 +2092,7 @@
   ResourceMark rm(THREAD);
   vframeStream st(THREAD);
 
-  BacktraceBuilder bt(backtrace);
+  BacktraceBuilder bt(THREAD, backtrace);
 
   // Unlike fill_in_stack_trace we do not skip fillInStackTrace or throwable init
   // methods as preallocated errors aren't created by "java" code.
@@ -2144,7 +2147,7 @@
                                          method,
                                          bte._version,
                                          bte._bci,
-                                         bte._cpref, CHECK);
+                                         bte._name, CHECK);
   }
 }
 
@@ -2159,15 +2162,14 @@
 
   Handle element = ik->allocate_instance_handle(CHECK_0);
 
-  int cpref = method->name_index();
   int version = method->constants()->version();
-  fill_in(element, method->method_holder(), method, version, bci, cpref, CHECK_0);
+  fill_in(element, method->method_holder(), method, version, bci, method->name(), CHECK_0);
   return element();
 }
 
 void java_lang_StackTraceElement::fill_in(Handle element,
                                           InstanceKlass* holder, const methodHandle& method,
-                                          int version, int bci, int cpref, TRAPS) {
+                                          int version, int bci, Symbol* name, TRAPS) {
   assert(element->is_a(SystemDictionary::StackTraceElement_klass()), "sanity check");
 
   // Fill in class name
@@ -2184,11 +2186,8 @@
       java_lang_StackTraceElement::set_classLoaderName(element(), loader_name);
   }
 
-  // The method can be NULL if the requested class version is gone
-  Symbol* sym = !method.is_null() ? method->name() : holder->constants()->symbol_at(cpref);
-
   // Fill in method name
-  oop methodname = StringTable::intern(sym, CHECK);
+  oop methodname = StringTable::intern(name, CHECK);
   java_lang_StackTraceElement::set_methodName(element(), methodname);
 
   // Fill in module name and version
@@ -2205,7 +2204,7 @@
     java_lang_StackTraceElement::set_moduleVersion(element(), module_version);
   }
 
-  if (!version_matches(method(), version)) {
+  if (method() == NULL || !version_matches(method(), version)) {
     // The method was redefined, accurate line number information isn't available
     java_lang_StackTraceElement::set_fileName(element(), NULL);
     java_lang_StackTraceElement::set_lineNumber(element(), -1);
@@ -2232,7 +2231,7 @@
 
 void java_lang_StackFrameInfo::set_method_and_bci(Handle stackFrame, const methodHandle& method, int bci) {
   // set Method* or mid/cpref
-  oop mname = stackFrame->obj_field(_memberName_offset);
+  Handle mname(Thread::current(), stackFrame->obj_field(_memberName_offset));
   InstanceKlass* ik = method->method_holder();
   CallInfo info(method(), ik);
   MethodHandles::init_method_MemberName(mname, info);
@@ -2252,8 +2251,8 @@
 
   short version = stackFrame->short_field(_version_offset);
   short bci = stackFrame->short_field(_bci_offset);
-  int cpref = method->name_index();
-  java_lang_StackTraceElement::fill_in(stack_trace_element, holder, method, version, bci, cpref, CHECK);
+  Symbol* name = method->name();
+  java_lang_StackTraceElement::fill_in(stack_trace_element, holder, method, version, bci, name, CHECK);
 }
 
 void java_lang_StackFrameInfo::compute_offsets() {
@@ -3966,7 +3965,6 @@
 
 void JavaClasses::check_offsets() {
   bool valid = true;
-  HandleMark hm;
 
 #define CHECK_OFFSET(klass_name, cpp_klass_name, field_name, field_sig) \
   valid &= check_offset(klass_name, cpp_klass_name :: field_name ## _offset, #field_name, field_sig)