--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/utilities/decoder.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 1997, 2015, 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
+ * 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.
+ *
+ */
+
+
+#ifndef SHARE_VM_UTILITIES_DECODER_HPP
+#define SHARE_VM_UTILITIES_DECODER_HPP
+
+#include "memory/allocation.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "utilities/ostream.hpp"
+
+class AbstractDecoder : public CHeapObj<mtInternal> {
+public:
+  virtual ~AbstractDecoder() {}
+
+  // status code for decoding native C frame
+  enum decoder_status {
+         not_available = -10,  // real decoder is not available
+         no_error = 0,         // successfully decoded frames
+         out_of_memory,        // out of memory
+         file_invalid,         // invalid elf file
+         file_not_found,       // could not found symbol file (on windows), such as jvm.pdb or jvm.map
+         helper_func_error,    // decoding functions not found (Windows only)
+         helper_init_error     // SymInitialize failed (Windows only)
+  };
+
+  // decode an pc address to corresponding function name and an offset from the beginning of
+  // the function
+  //
+  // Note: the 'base' variant does not demangle names. The
+  // demangling that was done systematically in the 'modulepath' variant
+  // is now optional.
+  virtual bool decode(address pc, char* buf, int buflen, int* offset,
+                      const char* modulepath = NULL, bool demangle = true) = 0;
+  virtual bool decode(address pc, char* buf, int buflen, int* offset, const void* base) = 0;
+
+  // demangle a C++ symbol
+  virtual bool demangle(const char* symbol, char* buf, int buflen) = 0;
+  // if the decoder can decode symbols in vm
+  virtual bool can_decode_C_frame_in_vm() const = 0;
+
+  virtual decoder_status status() const {
+    return _decoder_status;
+  }
+
+  virtual bool has_error() const {
+    return is_error(_decoder_status);
+  }
+
+  static bool is_error(decoder_status status) {
+    return (status > 0);
+  }
+
+protected:
+  decoder_status  _decoder_status;
+};
+
+// Do nothing decoder
+class NullDecoder : public AbstractDecoder {
+public:
+  NullDecoder() {
+    _decoder_status = not_available;
+  }
+
+  virtual ~NullDecoder() {};
+
+  virtual bool decode(address pc, char* buf, int buflen, int* offset,
+                      const char* modulepath, bool demangle) {
+    return false;
+  }
+
+  virtual bool decode(address pc, char* buf, int buflen, int* offset, const void* base) {
+    return false;
+  }
+
+  virtual bool demangle(const char* symbol, char* buf, int buflen) {
+    return false;
+  }
+
+  virtual bool can_decode_C_frame_in_vm() const {
+    return false;
+  }
+};
+
+
+class Decoder : AllStatic {
+public:
+  static bool decode(address pc, char* buf, int buflen, int* offset, const char* modulepath = NULL, bool demangle = true);
+  static bool decode(address pc, char* buf, int buflen, int* offset, bool demangle) {
+    return decode(pc, buf, buflen, offset, (const char*) NULL, demangle);
+  }
+  static bool decode(address pc, char* buf, int buflen, int* offset, const void* base);
+  static bool demangle(const char* symbol, char* buf, int buflen);
+  static bool can_decode_C_frame_in_vm();
+
+  // shutdown shared instance
+  static void shutdown();
+
+  static void print_state_on(outputStream* st);
+
+protected:
+  // shared decoder instance, _shared_instance_lock is needed
+  static AbstractDecoder* get_shared_instance();
+  // a private instance for error handler. Error handler can be
+  // triggered almost everywhere, including signal handler, where
+  // no lock can be taken. So the shared decoder can not be used
+  // in this scenario.
+  static AbstractDecoder* get_error_handler_instance();
+
+  static AbstractDecoder* create_decoder();
+private:
+  static AbstractDecoder*     _shared_decoder;
+  static AbstractDecoder*     _error_handler_decoder;
+  static NullDecoder          _do_nothing_decoder;
+
+protected:
+  static Mutex*               _shared_decoder_lock;
+  static Mutex* shared_decoder_lock();
+
+  friend class DecoderLocker;
+};
+
+class DecoderLocker : public MutexLockerEx {
+  AbstractDecoder* _decoder;
+  inline bool is_first_error_thread();
+public:
+  DecoderLocker();
+  AbstractDecoder* decoder() {
+    return _decoder;
+  }
+};
+
+#endif // SHARE_VM_UTILITIES_DECODER_HPP