--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/utilities/formatBuffer.hpp	Thu Jun 22 20:47:22 2017 -0400
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 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_FORMATBUFFER_HPP
+#define SHARE_VM_UTILITIES_FORMATBUFFER_HPP
+
+#include "utilities/globalDefinitions.hpp"
+#include "prims/jvm.h"
+#include <stdarg.h>
+
+// Simple class to format the ctor arguments into a fixed-sized buffer.
+class FormatBufferBase {
+ protected:
+  char* _buf;
+  inline FormatBufferBase(char* buf) : _buf(buf) {}
+ public:
+  static const int BufferSize = 256;
+  operator const char *() const { return _buf; }
+};
+
+// Use resource area for buffer
+class FormatBufferResource : public FormatBufferBase {
+ public:
+  FormatBufferResource(const char * format, ...) ATTRIBUTE_PRINTF(2, 3);
+};
+
+class FormatBufferDummy {};
+
+// Use stack for buffer
+template <size_t bufsz = FormatBufferBase::BufferSize>
+class FormatBuffer : public FormatBufferBase {
+ public:
+  inline FormatBuffer(const char* format, ...) ATTRIBUTE_PRINTF(2, 3);
+  // since va_list is unspecified type (can be char*), we use FormatBufferDummy to disambiguate these constructors
+  inline FormatBuffer(FormatBufferDummy dummy, const char* format, va_list ap) ATTRIBUTE_PRINTF(3, 0);
+  inline void append(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
+  inline void print(const char* format, ...)  ATTRIBUTE_PRINTF(2, 3);
+  inline void printv(const char* format, va_list ap) ATTRIBUTE_PRINTF(2, 0);
+
+  char* buffer() { return _buf; }
+  int size() { return bufsz; }
+
+ private:
+  FormatBuffer(const FormatBuffer &); // prevent copies
+  char _buffer[bufsz];
+
+ protected:
+  inline FormatBuffer();
+};
+
+template <size_t bufsz>
+FormatBuffer<bufsz>::FormatBuffer(const char * format, ...) : FormatBufferBase(_buffer) {
+  va_list argp;
+  va_start(argp, format);
+  jio_vsnprintf(_buf, bufsz, format, argp);
+  va_end(argp);
+}
+
+template <size_t bufsz>
+FormatBuffer<bufsz>::FormatBuffer(FormatBufferDummy dummy, const char * format, va_list ap) : FormatBufferBase(_buffer) {
+  jio_vsnprintf(_buf, bufsz, format, ap);
+}
+
+template <size_t bufsz>
+FormatBuffer<bufsz>::FormatBuffer() : FormatBufferBase(_buffer) {
+  _buf[0] = '\0';
+}
+
+template <size_t bufsz>
+void FormatBuffer<bufsz>::print(const char * format, ...) {
+  va_list argp;
+  va_start(argp, format);
+  jio_vsnprintf(_buf, bufsz, format, argp);
+  va_end(argp);
+}
+
+template <size_t bufsz>
+void FormatBuffer<bufsz>::printv(const char * format, va_list argp) {
+  jio_vsnprintf(_buf, bufsz, format, argp);
+}
+
+template <size_t bufsz>
+void FormatBuffer<bufsz>::append(const char* format, ...) {
+  // Given that the constructor does a vsnprintf we can assume that
+  // _buf is already initialized.
+  size_t len = strlen(_buf);
+  char* buf_end = _buf + len;
+
+  va_list argp;
+  va_start(argp, format);
+  jio_vsnprintf(buf_end, bufsz - len, format, argp);
+  va_end(argp);
+}
+
+// Used to format messages.
+typedef FormatBuffer<> err_msg;
+
+#endif // SHARE_VM_UTILITIES_FORMATBUFFER_HPP