Subzero: Add -Wshadow to the build.

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
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-parameter"
+#pragma clang diagnostic ignored "-Wshadow"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Compiler.h"
+#pragma clang diagnostic pop
+
 #include <cstdint>
 
 namespace Ice {
 
 class RandomNumberGenerator {
   RandomNumberGenerator() = delete;
   RandomNumberGenerator(const RandomNumberGenerator &) = delete;
   RandomNumberGenerator &operator=(const RandomNumberGenerator &) = delete;
 
 public:
   explicit RandomNumberGenerator(uint64_t Seed, llvm::StringRef Salt = "");
   uint64_t next(uint64_t Max);
 
 private:
   uint64_t State;
 };
 
 // This class adds additional random number generator utilities. The
 // reason for the wrapper class is that we want to keep the
 // RandomNumberGenerator interface identical to LLVM's.
 class RandomNumberGeneratorWrapper {
   RandomNumberGeneratorWrapper() = delete;
   RandomNumberGeneratorWrapper(const RandomNumberGeneratorWrapper &) = delete;
   RandomNumberGeneratorWrapper &
   operator=(const RandomNumberGeneratorWrapper &) = delete;
 
 public:
   uint64_t operator()(uint64_t Max) { return RNG.next(Max); }
   bool getTrueWithProbability(float Probability);
-  explicit RandomNumberGeneratorWrapper(RandomNumberGenerator &RNG)
-      : RNG(RNG) {}
+  explicit RandomNumberGeneratorWrapper(RandomNumberGenerator &MyRNG)
+      : RNG(MyRNG) {}
 
 private:
   RandomNumberGenerator &RNG;
 };
 
 // RandomShuffle is an implementation of std::random_shuffle() that
 // doesn't change across stdlib implementations.  Adapted from a
 // sample implementation at cppreference.com.
 template <class RandomIt, class RandomFunc>
 void RandomShuffle(RandomIt First, RandomIt Last, RandomFunc &&RNG) {
   for (auto i = Last - First - 1; i > 0; --i)
     std::swap(First[i], First[RNG(i + 1)]);
 }
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICERNG_H