Subzero: Add a random number generator.

src/IceRNG.h

+//===- subzero/src/IceRNG.h - Random number generator -----------*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares a random number generator.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBZERO_SRC_ICERNG_H
+#define SUBZERO_SRC_ICERNG_H
+
+#include <stdint.h>
+#include "llvm/ADT/StringRef.h"
+
+namespace Ice {
+
+class RandomNumberGenerator {
+public:
+  RandomNumberGenerator(llvm::StringRef Salt);
+  uint64_t next(uint64_t Max);
+
+private:
+  uint64_t State;
+};
+
+} // end of namespace Ice
+
+#endif // SUBZERO_SRC_ICERNG_H