--- /dev/null	2019-02-13 16:01:02.292000000 +0300
+++ new/src/share/vm/jfr/recorder/checkpoint/types/jfrTypeSet.cpp	2019-02-15 19:03:15.421507863 +0300
@@ -0,0 +1,901 @@
+/*
+ * Copyright (c) 2016, 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "classfile/classLoaderData.inline.hpp"
+#include "classfile/javaClasses.hpp"
+// XXX #include "classfile/packageEntry.hpp"
+#include "classfile/symbolTable.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "jfr/jfr.hpp"
+#include "jfr/jni/jfrGetAllEventClasses.hpp"
+#include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"
+#include "jfr/recorder/checkpoint/types/jfrTypeSet.hpp"
+#include "jfr/recorder/checkpoint/types/jfrTypeSetUtils.hpp"
+#include "jfr/recorder/checkpoint/types/jfrTypeSetWriter.hpp"
+#include "jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp"
+#include "jfr/recorder/storage/jfrBuffer.hpp"
+#include "jfr/utilities/jfrHashtable.hpp"
+#include "jfr/utilities/jfrTypes.hpp"
+#include "memory/iterator.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/instanceKlass.hpp"
+#include "oops/objArrayKlass.hpp"
+#include "oops/oop.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "utilities/accessFlags.hpp"
+
+// incremented on each checkpoint
+static u8 checkpoint_id = 0;
+
+// creates a unique id by combining a checkpoint relative symbol id (2^24)
+// with the current checkpoint id (2^40)
+#define CREATE_SYMBOL_ID(sym_id) (((u8)((checkpoint_id << 24) | sym_id)))
+
+typedef const Klass* KlassPtr;
+// XXX typedef const PackageEntry* PkgPtr;
+typedef const ClassLoaderData* CldPtr;
+typedef const Method* MethodPtr;
+typedef const Symbol* SymbolPtr;
+typedef const JfrSymbolId::SymbolEntry* SymbolEntryPtr;
+typedef const JfrSymbolId::CStringEntry* CStringEntryPtr;
+
+// XXX
+// static traceid package_id(KlassPtr klass) {
+//   assert(klass != NULL, "invariant");
+//   PkgPtr pkg_entry = klass->package();
+//   return pkg_entry == NULL ? 0 : TRACE_ID(pkg_entry);
+// }
+
+static traceid cld_id(CldPtr cld) {
+  assert(cld != NULL, "invariant");
+  return cld->is_anonymous() ? 0 : TRACE_ID(cld);
+}
+
+static void tag_leakp_klass_artifacts(KlassPtr k, bool class_unload) {
+  assert(k != NULL, "invariant");
+  // XXX
+  // PkgPtr pkg = k->package();
+  // if (pkg != NULL) {
+  //   tag_leakp_artifact(pkg, class_unload);
+  // }
+  CldPtr cld = k->class_loader_data();
+  assert(cld != NULL, "invariant");
+  if (!cld->is_anonymous()) {
+    tag_leakp_artifact(cld, class_unload);
+  }
+}
+
+class TagLeakpKlassArtifact {
+  bool _class_unload;
+ public:
+  TagLeakpKlassArtifact(bool class_unload) : _class_unload(class_unload) {}
+  bool operator()(KlassPtr klass) {
+    if (_class_unload) {
+      if (LEAKP_USED_THIS_EPOCH(klass)) {
+        tag_leakp_klass_artifacts(klass, _class_unload);
+      }
+    } else {
+      if (LEAKP_USED_PREV_EPOCH(klass)) {
+        tag_leakp_klass_artifacts(klass, _class_unload);
+      }
+    }
+    return true;
+  }
+};
+
+/*
+ * In C++03, functions used as template parameters must have external linkage;
+ * this restriction was removed in C++11. Change back to "static" and
+ * rename functions when C++11 becomes available.
+ *
+ * The weird naming is an effort to decrease the risk of name clashes.
+ */
+
+int write__artifact__klass(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* k) {
+  assert(writer != NULL, "invariant");
+  assert(artifacts != NULL, "invariant");
+  assert(k != NULL, "invariant");
+  KlassPtr klass = (KlassPtr)k;
+  traceid pkg_id = 0;
+  KlassPtr theklass = klass;
+  if (theklass->oop_is_objArray()) {
+    const ObjArrayKlass* obj_arr_klass = ObjArrayKlass::cast((Klass*)klass);
+    theklass = obj_arr_klass->bottom_klass();
+  }
+  if (theklass->oop_is_instance()) {
+    pkg_id = 0; // XXX package_id(theklass);
+  } else {
+    assert(theklass->oop_is_typeArray(), "invariant");
+  }
+  const traceid symbol_id = artifacts->mark(klass);
+  assert(symbol_id > 0, "need to have an address for symbol!");
+  writer->write(TRACE_ID(klass));
+  writer->write(cld_id(klass->class_loader_data()));
+  writer->write((traceid)CREATE_SYMBOL_ID(symbol_id));
+  writer->write(pkg_id);
+  writer->write((s4)klass->access_flags().get_flags());
+  return 1;
+}
+
+typedef LeakPredicate<KlassPtr> LeakKlassPredicate;
+typedef JfrPredicatedArtifactWriterImplHost<KlassPtr, LeakKlassPredicate, write__artifact__klass> LeakKlassWriterImpl;
+typedef JfrArtifactWriterHost<LeakKlassWriterImpl, TYPE_CLASS> LeakKlassWriter;
+typedef JfrArtifactWriterImplHost<KlassPtr, write__artifact__klass> KlassWriterImpl;
+typedef JfrArtifactWriterHost<KlassWriterImpl, TYPE_CLASS> KlassWriter;
+
+int write__artifact__method(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* m) {
+  assert(writer != NULL, "invariant");
+  assert(artifacts != NULL, "invariant");
+  assert(m != NULL, "invariant");
+  MethodPtr method = (MethodPtr)m;
+  const traceid method_name_symbol_id = artifacts->mark(method->name());
+  assert(method_name_symbol_id > 0, "invariant");
+  const traceid method_sig_symbol_id = artifacts->mark(method->signature());
+  assert(method_sig_symbol_id > 0, "invariant");
+  KlassPtr klass = method->method_holder();
+  assert(klass != NULL, "invariant");
+  assert(METHOD_USED_ANY_EPOCH(klass), "invariant");
+  writer->write((u8)METHOD_ID(klass, method));
+  writer->write((u8)TRACE_ID(klass));
+  writer->write((u8)CREATE_SYMBOL_ID(method_name_symbol_id));
+  writer->write((u8)CREATE_SYMBOL_ID(method_sig_symbol_id));
+  writer->write((u2)method->access_flags().get_flags());
+  writer->write(const_cast<Method*>(method)->is_hidden() ? (u1)1 : (u1)0);
+  return 1;
+}
+
+typedef JfrArtifactWriterImplHost<MethodPtr, write__artifact__method> MethodWriterImplTarget;
+typedef JfrArtifactWriterHost<MethodWriterImplTarget, TYPE_METHOD> MethodWriterImpl;
+
+// XXX
+// int write__artifact__package(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* p) {
+//   assert(writer != NULL, "invariant");
+//   assert(artifacts != NULL, "invariant");
+//   assert(p != NULL, "invariant");
+//   PkgPtr pkg = (PkgPtr)p;
+//   Symbol* const pkg_name = pkg->name();
+//   const traceid package_name_symbol_id = pkg_name != NULL ? artifacts->mark(pkg_name) : 0;
+//   assert(package_name_symbol_id > 0, "invariant");
+//   writer->write((traceid)TRACE_ID(pkg));
+//   writer->write((traceid)CREATE_SYMBOL_ID(package_name_symbol_id));
+//   writer->write((bool)pkg->is_exported());
+//   return 1;
+// }
+
+// typedef LeakPredicate<PkgPtr> LeakPackagePredicate;
+// int _compare_pkg_ptr_(PkgPtr const& lhs, PkgPtr const& rhs) { return lhs > rhs ? 1 : (lhs < rhs) ? -1 : 0; }
+// typedef UniquePredicate<PkgPtr, _compare_pkg_ptr_> PackagePredicate;
+// typedef JfrPredicatedArtifactWriterImplHost<PkgPtr, LeakPackagePredicate, write__artifact__package> LeakPackageWriterImpl;
+// typedef JfrPredicatedArtifactWriterImplHost<PkgPtr, PackagePredicate, write__artifact__package> PackageWriterImpl;
+// typedef JfrArtifactWriterHost<LeakPackageWriterImpl, TYPE_PACKAGE> LeakPackageWriter;
+// typedef JfrArtifactWriterHost<PackageWriterImpl, TYPE_PACKAGE> PackageWriter;
+
+int write__artifact__classloader(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* c) {
+  assert(c != NULL, "invariant");
+  CldPtr cld = (CldPtr)c;
+  assert(!cld->is_anonymous(), "invariant");
+  const traceid cld_id = TRACE_ID(cld);
+  // class loader type
+  const Klass* class_loader_klass = cld->class_loader() != NULL ? cld->class_loader()->klass() : NULL;
+  if (class_loader_klass == NULL) {
+    // (primordial) boot class loader
+    writer->write(cld_id); // class loader instance id
+    writer->write((traceid)0);  // class loader type id (absence of)
+    writer->write((traceid)CREATE_SYMBOL_ID(1)); // 1 maps to synthetic name -> "bootstrap"
+  } else {
+    Symbol* symbol_name = class_loader_klass->name();
+    const traceid symbol_name_id = symbol_name != NULL ? artifacts->mark(symbol_name) : 0;
+    writer->write(cld_id); // class loader instance id
+    writer->write(TRACE_ID(class_loader_klass)); // class loader type id
+    writer->write(symbol_name_id == 0 ? (traceid)0 :
+      (traceid)CREATE_SYMBOL_ID(symbol_name_id)); // class loader instance name
+  }
+  return 1;
+}
+
+typedef LeakPredicate<CldPtr> LeakCldPredicate;
+int _compare_cld_ptr_(CldPtr const& lhs, CldPtr const& rhs) { return lhs > rhs ? 1 : (lhs < rhs) ? -1 : 0; }
+typedef UniquePredicate<CldPtr, _compare_cld_ptr_> CldPredicate;
+typedef JfrPredicatedArtifactWriterImplHost<CldPtr, LeakCldPredicate, write__artifact__classloader> LeakCldWriterImpl;
+typedef JfrPredicatedArtifactWriterImplHost<CldPtr, CldPredicate, write__artifact__classloader> CldWriterImpl;
+typedef JfrArtifactWriterHost<LeakCldWriterImpl, TYPE_CLASSLOADER> LeakCldWriter;
+typedef JfrArtifactWriterHost<CldWriterImpl, TYPE_CLASSLOADER> CldWriter;
+
+typedef const JfrSymbolId::SymbolEntry* SymbolEntryPtr;
+
+static int write__artifact__symbol__entry__(JfrCheckpointWriter* writer,
+                                            SymbolEntryPtr entry) {
+  assert(writer != NULL, "invariant");
+  assert(entry != NULL, "invariant");
+  ResourceMark rm;
+  writer->write(CREATE_SYMBOL_ID(entry->id()));
+  writer->write(entry->value()->as_C_string());
+  return 1;
+}
+
+int write__artifact__symbol__entry(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* e) {
+  assert(e != NULL, "invariant");
+  return write__artifact__symbol__entry__(writer, (SymbolEntryPtr)e);
+}
+
+typedef JfrArtifactWriterImplHost<SymbolEntryPtr, write__artifact__symbol__entry> SymbolEntryWriterImpl;
+typedef JfrArtifactWriterHost<SymbolEntryWriterImpl, TYPE_SYMBOL> SymbolEntryWriter;
+
+typedef const JfrSymbolId::CStringEntry* CStringEntryPtr;
+
+static int write__artifact__cstring__entry__(JfrCheckpointWriter* writer, CStringEntryPtr entry) {
+  assert(writer != NULL, "invariant");
+  assert(entry != NULL, "invariant");
+  writer->write(CREATE_SYMBOL_ID(entry->id()));
+  writer->write(entry->value());
+  return 1;
+}
+
+int write__artifact__cstring__entry(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* e) {
+  assert(e != NULL, "invariant");
+  return write__artifact__cstring__entry__(writer, (CStringEntryPtr)e);
+}
+
+typedef JfrArtifactWriterImplHost<CStringEntryPtr, write__artifact__cstring__entry> CStringEntryWriterImpl;
+typedef JfrArtifactWriterHost<CStringEntryWriterImpl, TYPE_SYMBOL> CStringEntryWriter;
+
+int write__artifact__klass__symbol(JfrCheckpointWriter* writer, JfrArtifactSet* artifacts, const void* k) {
+  assert(writer != NULL, "invariant");
+  assert(artifacts != NULL, "invaiant");
+  assert(k != NULL, "invariant");
+  const InstanceKlass* const ik = (const InstanceKlass*)k;
+  if (ik->is_anonymous()) {
+    CStringEntryPtr entry =
+      artifacts->map_cstring(JfrSymbolId::anonymous_klass_name_hash_code(ik));
+    assert(entry != NULL, "invariant");
+    return write__artifact__cstring__entry__(writer, entry);
+  }
+
+  SymbolEntryPtr entry = artifacts->map_symbol(JfrSymbolId::regular_klass_name_hash_code(ik));
+  return write__artifact__symbol__entry__(writer, entry);
+}
+
+int _compare_traceid_(const traceid& lhs, const traceid& rhs) {
+  return lhs > rhs ? 1 : (lhs < rhs) ? -1 : 0;
+}
+
+template <template <typename> class Predicate>
+class KlassSymbolWriterImpl {
+ private:
+  JfrCheckpointWriter* _writer;
+  JfrArtifactSet* _artifacts;
+  Predicate<KlassPtr> _predicate;
+  MethodUsedPredicate<true> _method_used_predicate;
+  MethodFlagPredicate _method_flag_predicate;
+  UniquePredicate<traceid, _compare_traceid_> _unique_predicate;
+
+  int klass_symbols(KlassPtr klass);
+// XXX  int package_symbols(PkgPtr pkg);
+  int class_loader_symbols(CldPtr cld);
+  int method_symbols(KlassPtr klass);
+
+ public:
+  typedef KlassPtr Type;
+  KlassSymbolWriterImpl(JfrCheckpointWriter* writer,
+                        JfrArtifactSet* artifacts,
+                        bool class_unload) : _writer(writer),
+                                             _artifacts(artifacts),
+                                             _predicate(class_unload),
+                                             _method_used_predicate(class_unload),
+                                             _method_flag_predicate(class_unload),
+                                             _unique_predicate(class_unload) {}
+
+  int operator()(KlassPtr klass) {
+    assert(klass != NULL, "invariant");
+    int count = 0;
+    if (_predicate(klass)) {
+      count += klass_symbols(klass);
+      // XXX
+      // PkgPtr pkg = klass->package();
+      // if (pkg != NULL) {
+      //   count += package_symbols(pkg);
+      // }
+      CldPtr cld = klass->class_loader_data();
+      assert(cld != NULL, "invariant");
+      if (!cld->is_anonymous()) {
+        count += class_loader_symbols(cld);
+      }
+      if (_method_used_predicate(klass)) {
+        count += method_symbols(klass);
+      }
+    }
+    return count;
+  }
+};
+
+template <template <typename> class Predicate>
+int KlassSymbolWriterImpl<Predicate>::klass_symbols(KlassPtr klass) {
+  assert(klass != NULL, "invariant");
+  assert(_predicate(klass), "invariant");
+  const InstanceKlass* const ik = (const InstanceKlass*)klass;
+  if (ik->is_anonymous()) {
+    CStringEntryPtr entry =
+      this->_artifacts->map_cstring(JfrSymbolId::anonymous_klass_name_hash_code(ik));
+    assert(entry != NULL, "invariant");
+    return _unique_predicate(entry->id()) ? write__artifact__cstring__entry__(this->_writer, entry) : 0;
+  }
+  SymbolEntryPtr entry = this->_artifacts->map_symbol(ik->name());
+  assert(entry != NULL, "invariant");
+  return _unique_predicate(entry->id()) ? write__artifact__symbol__entry__(this->_writer, entry) : 0;
+}
+
+// XXX
+// template <template <typename> class Predicate>
+// int KlassSymbolWriterImpl<Predicate>::package_symbols(PkgPtr pkg) {
+//   assert(pkg != NULL, "invariant");
+//   SymbolPtr pkg_name = pkg->name();
+//   assert(pkg_name != NULL, "invariant");
+//   SymbolEntryPtr package_symbol = this->_artifacts->map_symbol(pkg_name);
+//   assert(package_symbol != NULL, "invariant");
+//   return _unique_predicate(package_symbol->id()) ?
+//     write__artifact__symbol__entry__(this->_writer, package_symbol) : 0;
+// }
+
+// XXX
+// template <template <typename> class Predicate>
+// int KlassSymbolWriterImpl<Predicate>::module_symbols(ModPtr module) {
+//   assert(module != NULL, "invariant");
+//   assert(module->is_named(), "invariant");
+//   int count = 0;
+//   SymbolPtr sym = module->name();
+//   SymbolEntryPtr entry = NULL;
+//   if (sym != NULL) {
+//     entry = this->_artifacts->map_symbol(sym);
+//     assert(entry != NULL, "invariant");
+//     if (_unique_predicate(entry->id())) {
+//       count += write__artifact__symbol__entry__(this->_writer, entry);
+//     }
+//   }
+//   sym = module->version();
+//   if (sym != NULL) {
+//     entry = this->_artifacts->map_symbol(sym);
+//     assert(entry != NULL, "invariant");
+//     if (_unique_predicate(entry->id())) {
+//       count += write__artifact__symbol__entry__(this->_writer, entry);
+//     }
+//   }
+//   sym = module->location();
+//   if (sym != NULL) {
+//     entry = this->_artifacts->map_symbol(sym);
+//     assert(entry != NULL, "invariant");
+//     if (_unique_predicate(entry->id())) {
+//       count += write__artifact__symbol__entry__(this->_writer, entry);
+//     }
+//   }
+//   return count;
+// }
+
+template <template <typename> class Predicate>
+int KlassSymbolWriterImpl<Predicate>::class_loader_symbols(CldPtr cld) {
+  assert(cld != NULL, "invariant");
+  assert(!cld->is_anonymous(), "invariant");
+  int count = 0;
+  // class loader type
+  const Klass* class_loader_klass = cld->class_loader() != NULL ? cld->class_loader()->klass() : NULL;
+  if (class_loader_klass == NULL) {
+    // (primordial) boot class loader
+    CStringEntryPtr entry = this->_artifacts->map_cstring(0);
+    assert(entry != NULL, "invariant");
+    assert(strncmp(entry->literal(),
+      BOOTSTRAP_LOADER_NAME,
+      BOOTSTRAP_LOADER_NAME_LEN) == 0, "invariant");
+    if (_unique_predicate(entry->id())) {
+      count += write__artifact__cstring__entry__(this->_writer, entry);
+    }
+  } else {
+    const Symbol* class_loader_name = class_loader_klass->name()/* XXX TODO cld->name()*/;
+    if (class_loader_name != NULL) {
+      SymbolEntryPtr entry = this->_artifacts->map_symbol(class_loader_name);
+      assert(entry != NULL, "invariant");
+      if (_unique_predicate(entry->id())) {
+        count += write__artifact__symbol__entry__(this->_writer, entry);
+      }
+    }
+  }
+  return count;
+}
+
+template <template <typename> class Predicate>
+int KlassSymbolWriterImpl<Predicate>::method_symbols(KlassPtr klass) {
+  assert(_predicate(klass), "invariant");
+  assert(_method_used_predicate(klass), "invariant");
+  assert(METHOD_AND_CLASS_USED_ANY_EPOCH(klass), "invariant");
+  int count = 0;
+  const InstanceKlass* const ik = InstanceKlass::cast((Klass*)klass);
+  const int len = ik->methods()->length();
+  for (int i = 0; i < len; ++i) {
+    MethodPtr method = ik->methods()->at(i);
+    if (_method_flag_predicate(method)) {
+      SymbolEntryPtr entry = this->_artifacts->map_symbol(method->name());
+      assert(entry != NULL, "invariant");
+      if (_unique_predicate(entry->id())) {
+        count += write__artifact__symbol__entry__(this->_writer, entry);
+      }
+      entry = this->_artifacts->map_symbol(method->signature());
+      assert(entry != NULL, "invariant");
+      if (_unique_predicate(entry->id())) {
+        count += write__artifact__symbol__entry__(this->_writer, entry);
+      }
+    }
+  }
+  return count;
+}
+
+typedef KlassSymbolWriterImpl<LeakPredicate> LeakKlassSymbolWriterImpl;
+typedef JfrArtifactWriterHost<LeakKlassSymbolWriterImpl, TYPE_SYMBOL> LeakKlassSymbolWriter;
+
+class ClearKlassAndMethods {
+ private:
+  ClearArtifact<KlassPtr> _clear_klass_tag_bits;
+  ClearArtifact<MethodPtr> _clear_method_flag;
+  MethodUsedPredicate<false> _method_used_predicate;
+
+ public:
+  ClearKlassAndMethods(bool class_unload) : _clear_klass_tag_bits(class_unload),
+                                            _clear_method_flag(class_unload),
+                                            _method_used_predicate(class_unload) {}
+  bool operator()(KlassPtr klass) {
+    if (_method_used_predicate(klass)) {
+      const InstanceKlass* ik = InstanceKlass::cast((Klass*)klass);
+      const int len = ik->methods()->length();
+      for (int i = 0; i < len; ++i) {
+        MethodPtr method = ik->methods()->at(i);
+        _clear_method_flag(method);
+      }
+    }
+    _clear_klass_tag_bits(klass);
+    return true;
+  }
+};
+
+typedef CompositeFunctor<KlassPtr,
+                         TagLeakpKlassArtifact,
+                         LeakKlassWriter> LeakpKlassArtifactTagging;
+
+typedef CompositeFunctor<KlassPtr,
+                         LeakpKlassArtifactTagging,
+                         KlassWriter> CompositeKlassWriter;
+
+typedef CompositeFunctor<KlassPtr,
+                         CompositeKlassWriter,
+                         KlassArtifactRegistrator> CompositeKlassWriterRegistration;
+
+typedef CompositeFunctor<KlassPtr,
+                         KlassWriter,
+                         KlassArtifactRegistrator> KlassWriterRegistration;
+
+typedef JfrArtifactCallbackHost<KlassPtr, KlassWriterRegistration> KlassCallback;
+typedef JfrArtifactCallbackHost<KlassPtr, CompositeKlassWriterRegistration> CompositeKlassCallback;
+
+/*
+ * Composite operation
+ *
+ * TagLeakpKlassArtifact ->
+ *   LeakpPredicate ->
+ *     LeakpKlassWriter ->
+ *       KlassPredicate ->
+ *         KlassWriter ->
+ *           KlassWriterRegistration
+ */
+void JfrTypeSet::write_klass_constants(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer) {
+  assert(!_artifacts->has_klass_entries(), "invariant");
+  KlassArtifactRegistrator reg(_artifacts);
+  KlassWriter kw(writer, _artifacts, _class_unload);
+  KlassWriterRegistration kwr(&kw, &reg);
+  if (leakp_writer == NULL) {
+    KlassCallback callback(&kwr);
+    _subsystem_callback = &callback;
+    do_klasses();
+    return;
+  }
+  TagLeakpKlassArtifact tagging(_class_unload);
+  LeakKlassWriter lkw(leakp_writer, _artifacts, _class_unload);
+  LeakpKlassArtifactTagging lpkat(&tagging, &lkw);
+  CompositeKlassWriter ckw(&lpkat, &kw);
+  CompositeKlassWriterRegistration ckwr(&ckw, &reg);
+  CompositeKlassCallback callback(&ckwr);
+  _subsystem_callback = &callback;
+  do_klasses();
+}
+
+// XXX
+// typedef CompositeFunctor<PkgPtr,
+//                          PackageWriter,
+//                          ClearArtifact<PkgPtr> > PackageWriterWithClear;
+
+// typedef CompositeFunctor<PkgPtr,
+//                          LeakPackageWriter,
+//                          PackageWriter> CompositePackageWriter;
+
+// typedef CompositeFunctor<PkgPtr,
+//                          CompositePackageWriter,
+//                          ClearArtifact<PkgPtr> > CompositePackageWriterWithClear;
+
+// class PackageFieldSelector {
+//  public:
+//   typedef PkgPtr TypePtr;
+//   static TypePtr select(KlassPtr klass) {
+//     assert(klass != NULL, "invariant");
+//     return ((InstanceKlass*)klass)->package();
+//   }
+// };
+
+// typedef KlassToFieldEnvelope<PackageFieldSelector,
+//                              PackageWriterWithClear> KlassPackageWriterWithClear;
+
+// typedef KlassToFieldEnvelope<PackageFieldSelector,
+//                              CompositePackageWriterWithClear> KlassCompositePackageWriterWithClear;
+
+// typedef JfrArtifactCallbackHost<PkgPtr, PackageWriterWithClear> PackageCallback;
+// typedef JfrArtifactCallbackHost<PkgPtr, CompositePackageWriterWithClear> CompositePackageCallback;
+
+// /*
+//  * Composite operation
+//  *
+//  * LeakpPackageWriter ->
+//  *   PackageWriter ->
+//  *     ClearArtifact<PackageEntry>
+//  *
+//  */
+// void JfrTypeSet::write_package_constants(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer) {
+//   assert(_artifacts->has_klass_entries(), "invariant");
+//   ClearArtifact<PkgPtr> clear(_class_unload);
+//   PackageWriter pw(writer, _artifacts, _class_unload);
+//   if (leakp_writer == NULL) {
+//     PackageWriterWithClear pwwc(&pw, &clear);
+//     KlassPackageWriterWithClear kpwwc(&pwwc);
+//     _artifacts->iterate_klasses(kpwwc);
+//     PackageCallback callback(&pwwc);
+//     _subsystem_callback = &callback;
+//     do_packages();
+//     return;
+//   }
+//   LeakPackageWriter lpw(leakp_writer, _artifacts, _class_unload);
+//   CompositePackageWriter cpw(&lpw, &pw);
+//   CompositePackageWriterWithClear cpwwc(&cpw, &clear);
+//   KlassCompositePackageWriterWithClear ckpw(&cpwwc);
+//   _artifacts->iterate_klasses(ckpw);
+//   CompositePackageCallback callback(&cpwwc);
+//   _subsystem_callback = &callback;
+//   do_packages();
+// }
+
+// typedef CompositeFunctor<ModPtr,
+//                          ModuleWriter,
+//                          ClearArtifact<ModPtr> > ModuleWriterWithClear;
+
+// typedef CompositeFunctor<ModPtr,
+//                          LeakModuleWriter,
+//                          ModuleWriter> CompositeModuleWriter;
+
+// typedef CompositeFunctor<ModPtr,
+//                          CompositeModuleWriter,
+//                          ClearArtifact<ModPtr> > CompositeModuleWriterWithClear;
+
+// typedef JfrArtifactCallbackHost<ModPtr, ModuleWriterWithClear> ModuleCallback;
+// typedef JfrArtifactCallbackHost<ModPtr, CompositeModuleWriterWithClear> CompositeModuleCallback;
+
+// XXX
+// class ModuleFieldSelector {
+//  public:
+//   typedef ModPtr TypePtr;
+//   static TypePtr select(KlassPtr klass) {
+//     assert(klass != NULL, "invariant");
+//     PkgPtr pkg = klass->package();
+//     return pkg != NULL ? pkg->module() : NULL;
+//   }
+// };
+
+// typedef KlassToFieldEnvelope<ModuleFieldSelector,
+//                              ModuleWriterWithClear> KlassModuleWriterWithClear;
+
+// typedef KlassToFieldEnvelope<ModuleFieldSelector,
+//                              CompositeModuleWriterWithClear> KlassCompositeModuleWriterWithClear;
+
+typedef CompositeFunctor<CldPtr, CldWriter, ClearArtifact<CldPtr> > CldWriterWithClear;
+typedef CompositeFunctor<CldPtr, LeakCldWriter, CldWriter> CompositeCldWriter;
+typedef CompositeFunctor<CldPtr, CompositeCldWriter, ClearArtifact<CldPtr> > CompositeCldWriterWithClear;
+typedef JfrArtifactCallbackHost<CldPtr, CldWriterWithClear> CldCallback;
+typedef JfrArtifactCallbackHost<CldPtr, CompositeCldWriterWithClear> CompositeCldCallback;
+
+class CldFieldSelector {
+ public:
+  typedef CldPtr TypePtr;
+  static TypePtr select(KlassPtr klass) {
+    assert(klass != NULL, "invariant");
+    CldPtr cld = klass->class_loader_data();
+    return cld->is_anonymous() ? NULL : cld;
+  }
+};
+
+typedef KlassToFieldEnvelope<CldFieldSelector, CldWriterWithClear> KlassCldWriterWithClear;
+typedef KlassToFieldEnvelope<CldFieldSelector, CompositeCldWriterWithClear> KlassCompositeCldWriterWithClear;
+
+/*
+ * Composite operation
+ *
+ * LeakpClassLoaderWriter ->
+ *   ClassLoaderWriter ->
+ *     ClearArtifact<ClassLoaderData>
+ */
+void JfrTypeSet::write_class_loader_constants(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer) {
+  assert(_artifacts->has_klass_entries(), "invariant");
+  ClearArtifact<CldPtr> clear(_class_unload);
+  CldWriter cldw(writer, _artifacts, _class_unload);
+  if (leakp_writer == NULL) {
+    CldWriterWithClear cldwwc(&cldw, &clear);
+    KlassCldWriterWithClear kcldwwc(&cldwwc);
+    _artifacts->iterate_klasses(kcldwwc);
+    CldCallback callback(&cldwwc);
+    _subsystem_callback = &callback;
+    do_class_loaders();
+    return;
+  }
+  LeakCldWriter lcldw(leakp_writer, _artifacts, _class_unload);
+  CompositeCldWriter ccldw(&lcldw, &cldw);
+  CompositeCldWriterWithClear ccldwwc(&ccldw, &clear);
+  KlassCompositeCldWriterWithClear kcclwwc(&ccldwwc);
+  _artifacts->iterate_klasses(kcclwwc);
+  CompositeCldCallback callback(&ccldwwc);
+  _subsystem_callback = &callback;
+  do_class_loaders();
+}
+
+template <bool predicate_bool, typename MethodFunctor>
+class MethodIteratorHost {
+ private:
+  MethodFunctor _method_functor;
+  MethodUsedPredicate<predicate_bool> _method_used_predicate;
+  MethodFlagPredicate _method_flag_predicate;
+
+ public:
+  MethodIteratorHost(JfrCheckpointWriter* writer,
+                     JfrArtifactSet* artifacts,
+                     bool class_unload,
+                     bool skip_header = false) :
+    _method_functor(writer, artifacts, class_unload, skip_header),
+    _method_used_predicate(class_unload),
+    _method_flag_predicate(class_unload) {}
+
+  bool operator()(KlassPtr klass) {
+    if (_method_used_predicate(klass)) {
+      assert(METHOD_AND_CLASS_USED_ANY_EPOCH(klass), "invariant");
+      const InstanceKlass* ik = InstanceKlass::cast((Klass*)klass);
+      const int len = ik->methods()->length();
+      for (int i = 0; i < len; ++i) {
+        MethodPtr method = ik->methods()->at(i);
+        if (_method_flag_predicate(method)) {
+          _method_functor(method);
+        }
+      }
+    }
+    return true;
+  }
+
+  int count() const { return _method_functor.count(); }
+  void add(int count) { _method_functor.add(count); }
+};
+
+typedef MethodIteratorHost<true /*leakp */,  MethodWriterImpl> LeakMethodWriter;
+typedef MethodIteratorHost<false, MethodWriterImpl> MethodWriter;
+typedef CompositeFunctor<KlassPtr, LeakMethodWriter, MethodWriter> CompositeMethodWriter;
+
+/*
+ * Composite operation
+ *
+ * LeakpMethodWriter ->
+ *   MethodWriter
+ */
+void JfrTypeSet::write_method_constants(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer) {
+  assert(_artifacts->has_klass_entries(), "invariant");
+  MethodWriter mw(writer, _artifacts, _class_unload);
+  if (leakp_writer == NULL) {
+    _artifacts->iterate_klasses(mw);
+    return;
+  }
+  LeakMethodWriter lpmw(leakp_writer, _artifacts, _class_unload);
+  CompositeMethodWriter cmw(&lpmw, &mw);
+  _artifacts->iterate_klasses(cmw);
+}
+static void write_symbols_leakp(JfrCheckpointWriter* leakp_writer, JfrArtifactSet* artifacts, bool class_unload) {
+  assert(leakp_writer != NULL, "invariant");
+  assert(artifacts != NULL, "invariant");
+  LeakKlassSymbolWriter lpksw(leakp_writer, artifacts, class_unload);
+  artifacts->iterate_klasses(lpksw);
+}
+static void write_symbols(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, JfrArtifactSet* artifacts, bool class_unload) {
+  assert(writer != NULL, "invariant");
+  assert(artifacts != NULL, "invariant");
+  if (leakp_writer != NULL) {
+    write_symbols_leakp(leakp_writer, artifacts, class_unload);
+  }
+  // iterate all registered symbols
+  SymbolEntryWriter symbol_writer(writer, artifacts, class_unload);
+  artifacts->iterate_symbols(symbol_writer);
+  CStringEntryWriter cstring_writer(writer, artifacts, class_unload, true); // skip header
+  artifacts->iterate_cstrings(cstring_writer);
+  symbol_writer.add(cstring_writer.count());
+}
+
+bool JfrTypeSet::_class_unload = false;
+JfrArtifactSet* JfrTypeSet::_artifacts = NULL;
+JfrArtifactClosure* JfrTypeSet::_subsystem_callback = NULL;
+
+void JfrTypeSet::write_symbol_constants(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer) {
+  assert(writer != NULL, "invariant");
+  assert(_artifacts->has_klass_entries(), "invariant");
+  write_symbols(writer, leakp_writer, _artifacts, _class_unload);
+}
+
+void JfrTypeSet::do_unloaded_klass(Klass* klass) {
+  assert(klass != NULL, "invariant");
+  assert(_subsystem_callback != NULL, "invariant");
+  if (IS_JDK_JFR_EVENT_SUBKLASS(klass)) {
+    JfrEventClasses::increment_unloaded_event_class();
+  }
+  if (USED_THIS_EPOCH(klass)) { // includes leakp subset
+    _subsystem_callback->do_artifact(klass);
+    return;
+  }
+  if (klass->is_subclass_of(SystemDictionary::ClassLoader_klass()) || klass == SystemDictionary::Object_klass()) {
+    SET_LEAKP_USED_THIS_EPOCH(klass); // tag leakp "safe byte" for subset inclusion
+    _subsystem_callback->do_artifact(klass);
+  }
+}
+
+void JfrTypeSet::do_klass(Klass* klass) {
+  assert(klass != NULL, "invariant");
+  assert(_subsystem_callback != NULL, "invariant");
+  if (USED_PREV_EPOCH(klass)) { // includes leakp subset
+    _subsystem_callback->do_artifact(klass);
+    return;
+  }
+  if (klass->is_subclass_of(SystemDictionary::ClassLoader_klass()) || klass == SystemDictionary::Object_klass()) {
+    SET_LEAKP_USED_PREV_EPOCH(klass); // tag leakp "safe byte" for subset inclusion
+    _subsystem_callback->do_artifact(klass);
+  }
+}
+
+void JfrTypeSet::do_klasses() {
+  if (_class_unload) {
+    ClassLoaderDataGraph::classes_unloading_do(&do_unloaded_klass);
+    return;
+  }
+  ClassLoaderDataGraph::classes_do(&do_klass);
+}
+
+// XXX
+// void JfrTypeSet::do_unloaded_package(PackageEntry* entry) {
+//   assert(entry != NULL, "invariant");
+//   assert(_subsystem_callback != NULL, "invariant");
+//   if (ANY_USED_THIS_EPOCH(entry)) { // includes leakp subset
+//     _subsystem_callback->do_artifact(entry);
+//   }
+// }
+
+// void JfrTypeSet::do_package(PackageEntry* entry) {
+//   assert(_subsystem_callback != NULL, "invariant");
+//   if (ANY_USED_PREV_EPOCH(entry)) { // includes leakp subset
+//     _subsystem_callback->do_artifact(entry);
+//   }
+// }
+
+// void JfrTypeSet::do_packages() {
+//   if (_class_unload) {
+//     ClassLoaderDataGraph::packages_unloading_do(&do_unloaded_package);
+//     return;
+//   }
+//   ClassLoaderDataGraph::packages_do(&do_package);
+// }
+
+void JfrTypeSet::do_unloaded_class_loader_data(ClassLoaderData* cld) {
+  assert(_subsystem_callback != NULL, "invariant");
+  if (ANY_USED_THIS_EPOCH(cld)) { // includes leakp subset
+    _subsystem_callback->do_artifact(cld);
+  }
+}
+
+void JfrTypeSet::do_class_loader_data(ClassLoaderData* cld) {
+  assert(_subsystem_callback != NULL, "invariant");
+  if (ANY_USED_PREV_EPOCH(cld)) { // includes leakp subset
+    _subsystem_callback->do_artifact(cld);
+  }
+}
+
+class CLDCallback : public CLDClosure {
+ private:
+  bool _class_unload;
+ public:
+  CLDCallback(bool class_unload) : _class_unload(class_unload) {}
+  void do_cld(ClassLoaderData* cld) {
+     assert(cld != NULL, "invariant");
+    if (cld->is_anonymous()) {
+      return;
+    }
+    if (_class_unload) {
+      JfrTypeSet::do_unloaded_class_loader_data(cld);
+      return;
+    }
+    JfrTypeSet::do_class_loader_data(cld);
+  }
+};
+
+void JfrTypeSet::do_class_loaders() {
+  CLDCallback cld_cb(_class_unload);
+  if (_class_unload) {
+    ClassLoaderDataGraph::cld_unloading_do(&cld_cb);
+    return;
+  }
+  ClassLoaderDataGraph::cld_do(&cld_cb);
+}
+
+static void clear_artifacts(JfrArtifactSet* artifacts,
+                            bool class_unload) {
+  assert(artifacts != NULL, "invariant");
+  assert(artifacts->has_klass_entries(), "invariant");
+
+  // untag
+  ClearKlassAndMethods clear(class_unload);
+  artifacts->iterate_klasses(clear);
+  artifacts->clear();
+}
+
+/**
+ * Write all "tagged" (in-use) constant artifacts and their dependencies.
+ */
+void JfrTypeSet::serialize(JfrCheckpointWriter* writer, JfrCheckpointWriter* leakp_writer, bool class_unload) {
+  assert(writer != NULL, "invariant");
+  ResourceMark rm;
+  // initialization begin
+  _class_unload = class_unload;
+  ++checkpoint_id;
+  if (_artifacts == NULL) {
+    _artifacts = new JfrArtifactSet(class_unload);
+    _subsystem_callback = NULL;
+  } else {
+    _artifacts->initialize(class_unload);
+    _subsystem_callback = NULL;
+  }
+  assert(_artifacts != NULL, "invariant");
+  assert(!_artifacts->has_klass_entries(), "invariant");
+  assert(_subsystem_callback == NULL, "invariant");
+  // initialization complete
+
+  // write order is important because an individual write step
+  // might tag an artifact to be written in a subsequent step
+  write_klass_constants(writer, leakp_writer);
+  if (_artifacts->has_klass_entries()) {
+// XXX    write_package_constants(writer, leakp_writer);
+    write_class_loader_constants(writer, leakp_writer);
+    write_method_constants(writer, leakp_writer);
+    write_symbol_constants(writer, leakp_writer);
+    clear_artifacts(_artifacts, class_unload);
+  }
+}