diff -r 5b173b4ca846 -r 32c42d627f41 hotspot/src/os/windows/vm/decoder_windows.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/os/windows/vm/decoder_windows.cpp	Sat Dec 11 13:20:56 2010 -0500
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 1997, 2010, 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 "prims/jvm.h"
+#include "utilities/decoder.hpp"
+
+HMODULE                   Decoder::_dbghelp_handle = NULL;
+bool                      Decoder::_can_decode_in_vm = false;
+pfn_SymGetSymFromAddr64   Decoder::_pfnSymGetSymFromAddr64 = NULL;
+pfn_UndecorateSymbolName  Decoder::_pfnUndecorateSymbolName = NULL;
+
+void Decoder::initialize() {
+  if (!_initialized) {
+    _initialized = true;
+
+    HMODULE handle = ::LoadLibrary("dbghelp.dll");
+    if (!handle) {
+      _decoder_status = helper_not_found;
+        return;
+    }
+
+    _dbghelp_handle = handle;
+
+    pfn_SymSetOptions _pfnSymSetOptions = (pfn_SymSetOptions)::GetProcAddress(handle, "SymSetOptions");
+    pfn_SymInitialize _pfnSymInitialize = (pfn_SymInitialize)::GetProcAddress(handle, "SymInitialize");
+    _pfnSymGetSymFromAddr64 = (pfn_SymGetSymFromAddr64)::GetProcAddress(handle, "SymGetSymFromAddr64");
+    _pfnUndecorateSymbolName = (pfn_UndecorateSymbolName)GetProcAddress(handle, "UnDecorateSymbolName");
+
+    if (_pfnSymSetOptions == NULL || _pfnSymInitialize == NULL || _pfnSymGetSymFromAddr64 == NULL) {
+      _pfnSymGetSymFromAddr64 = NULL;
+      _pfnUndecorateSymbolName = NULL;
+      ::FreeLibrary(handle);
+      _dbghelp_handle = NULL;
+      _decoder_status = helper_func_error;
+      return;
+    }
+
+    _pfnSymSetOptions(SYMOPT_UNDNAME | SYMOPT_DEFERRED_LOADS);
+    if (!_pfnSymInitialize(GetCurrentProcess(), NULL, TRUE)) {
+      _pfnSymGetSymFromAddr64 = NULL;
+      _pfnUndecorateSymbolName = NULL;
+      ::FreeLibrary(handle);
+      _dbghelp_handle = NULL;
+      _decoder_status = helper_init_error;
+      return;
+    }
+
+     // find out if jvm.dll contains private symbols, by decoding
+     // current function and comparing the result
+     address addr = (address)Decoder::initialize;
+     char buf[MAX_PATH];
+     if (decode(addr, buf, sizeof(buf), NULL) == no_error) {
+       _can_decode_in_vm = !strcmp(buf, "Decoder::initialize");
+     }
+  }
+}
+
+void Decoder::uninitialize() {
+  assert(_initialized, "Decoder not yet initialized");
+  _pfnSymGetSymFromAddr64 = NULL;
+  _pfnUndecorateSymbolName = NULL;
+  if (_dbghelp_handle != NULL) {
+    ::FreeLibrary(_dbghelp_handle);
+  }
+  _initialized = false;
+}
+
+bool Decoder::can_decode_C_frame_in_vm() {
+  initialize();
+  return  _can_decode_in_vm;
+}
+
+
+Decoder::decoder_status Decoder::decode(address addr, char *buf, int buflen, int *offset) {
+  assert(_initialized, "Decoder not yet initialized");
+  if (_pfnSymGetSymFromAddr64 != NULL) {
+    PIMAGEHLP_SYMBOL64 pSymbol;
+    char symbolInfo[MAX_PATH + sizeof(IMAGEHLP_SYMBOL64)];
+    pSymbol = (PIMAGEHLP_SYMBOL64)symbolInfo;
+    pSymbol->MaxNameLength = MAX_PATH;
+    pSymbol->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL64);
+    DWORD64 displacement;
+    if (_pfnSymGetSymFromAddr64(::GetCurrentProcess(), (DWORD64)addr, &displacement, pSymbol)) {
+      if (buf != NULL) {
+        if (!demangle(pSymbol->Name, buf, buflen)) {
+          jio_snprintf(buf, buflen, "%s", pSymbol->Name);
+        }
+      }
+      if (offset != NULL) *offset = (int)displacement;
+      return no_error;
+    }
+  }
+  return helper_not_found;
+}
+
+bool Decoder::demangle(const char* symbol, char *buf, int buflen) {
+  assert(_initialized, "Decoder not yet initialized");
+  return _pfnUndecorateSymbolName != NULL &&
+         _pfnUndecorateSymbolName(symbol, buf, buflen, UNDNAME_COMPLETE);
+}
+