--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/logging/logPrefix.hpp	Thu Sep 24 12:36:04 2015 +0200
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2015, 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_LOGGING_LOGPREFIX_HPP
+#define SHARE_VM_LOGGING_LOGPREFIX_HPP
+
+#include "gc/shared/gcId.hpp"
+#include "logging/logTag.hpp"
+
+// Prefixes prepend each log message for a specified tagset with the given prefix.
+// A prefix consists of a format string and a value or callback. Prefixes are added
+// after the decorations but before the log message.
+//
+// List of prefixes for specific tags and/or tagsets.
+// Syntax: LOG_PREFIX(<printf format>, <value/callback for value>, LOG_TAGS(<chosen log tags>))
+#define LOG_PREFIX_LIST // Currently unused/empty
+
+// The empty prefix, used when there's no prefix defined.
+template <LogTagType T0, LogTagType T1, LogTagType T2, LogTagType T3, LogTagType T4, LogTagType GuardTag = LogTag::__NO_TAG>
+struct LogPrefix : public AllStatic {
+  STATIC_ASSERT(GuardTag == LogTag::__NO_TAG);
+  static size_t prefix(char* buf, size_t len) {
+    return 0;
+  }
+};
+
+#define LOG_PREFIX(fmt, fn, ...) \
+template <> struct LogPrefix<__VA_ARGS__> { \
+  static size_t prefix(char* buf, size_t len) { \
+    int ret = jio_snprintf(buf, len, fmt, fn); \
+    assert(ret >= 0, \
+           err_msg("Failed to prefix log message using prefix ('%s', '%s'), log buffer too small?", fmt, #fn)); \
+    return ret; \
+  } \
+};
+LOG_PREFIX_LIST
+#undef LOG_PREFIX
+
+#endif // SHARE_VM_LOGGING_LOGPREFIX_HPP