Use separate random number generator for each randomization pass

src/IceGlobalContext.h

 //===- subzero/src/IceGlobalContext.h - Global context defs -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 225 matching lines @@
   template <typename T>
   typename std::enable_if<!std::is_trivially_destructible<T>::value, T>::type *
   allocate() {
     T *Ret = getAllocator()->Allocate<T>();
     getDestructors()->emplace_back([Ret]() { Ret->~T(); });
     return Ret;
   }
 
   const Intrinsics &getIntrinsicsInfo() const { return IntrinsicsInfo; }
 
-  // TODO(wala,stichnot): Make the RNG play nicely with multithreaded
-  // translation.
-  RandomNumberGenerator &getRNG() { return RNG; }
-
   ELFObjectWriter *getObjectWriter() const { return ObjectWriter.get(); }
 
   /// Reset stats at the beginning of a function.
   void resetStats() {
     if (BuildDefs::dump())
       ICE_TLS_GET_FIELD(TLS)->StatsFunction.reset();
   }
   void dumpStats(const IceString &Name, bool Final = false);
   void statsUpdateEmitted(uint32_t InstCount) {
     if (!getFlags().getDumpStats())
@@ skipping 173 matching lines @@
   /// This is used in a few cases where we want to take some action on
   /// a particular function or symbol based on a command-line argument,
   /// such as changing the verbose level for a particular function.  An
   /// empty Match argument means match everything.  Returns true if
   /// there is a match.
   static bool matchSymbolName(const IceString &SymbolName,
                               const IceString &Match) {
     return Match.empty() || Match == SymbolName;
   }
 
-  /// Return the randomization cookie for diversification.
-  /// Initialize the cookie if necessary
-  uint32_t getRandomizationCookie() const { return RandomizationCookie; }
-
 private:
   // Try to ensure mutexes are allocated on separate cache lines.
 
   // Destructors collaborate with Allocator
   ICE_CACHELINE_BOUNDARY;
   // Managed by getAllocator()
   GlobalLockType AllocLock;
   ArenaAllocator<> Allocator;
 
   ICE_CACHELINE_BOUNDARY;
@@ skipping 32 matching lines @@
   typedef std::mutex StrLockType;
   StrLockType StrLock;
   Ostream *StrDump;  /// Stream for dumping / diagnostics
   Ostream *StrEmit;  /// Stream for code emission
   Ostream *StrError; /// Stream for logging errors.
 
   ICE_CACHELINE_BOUNDARY;
 
   Intrinsics IntrinsicsInfo;
   const ClFlags &Flags;
-  RandomNumberGenerator RNG; // TODO(stichnot): Move into Cfg.
   // TODO(jpp): move to EmitterContext.
   std::unique_ptr<ELFObjectWriter> ObjectWriter;
   BoundedProducerConsumerQueue<Cfg> OptQ;
   BoundedProducerConsumerQueue<EmitterWorkItem> EmitQ;
   // DataLowering is only ever used by a single thread at a time (either in
   // emitItems(), or in IceCompiler::run before the compilation is over.)
   // TODO(jpp): move to EmitterContext.
   std::unique_ptr<TargetDataLowering> DataLowering;
   /// If !HasEmittedCode, SubZero will accumulate all Globals (which are "true"
   /// program global variables) until the first code WorkItem is seen.
@@ skipping 40 matching lines @@
   llvm::SmallVector<std::thread, 128> TranslationThreads;
   llvm::SmallVector<std::thread, 128> EmitterThreads;
   // Each thread has its own TLS pointer which is also held in
   // AllThreadContexts.
   ICE_TLS_DECLARE_FIELD(ThreadContext *, TLS);
 
   // Private helpers for mangleName()
   typedef llvm::SmallVector<char, 32> ManglerVector;
   void incrementSubstitutions(ManglerVector &OldName) const;
 
-  // Randomization Cookie
-  // Managed by getRandomizationCookie()
-  GlobalLockType RandomizationCookieLock;
-  uint32_t RandomizationCookie = 0;
-
 public:
   static void TlsInit() { ICE_TLS_INIT_FIELD(TLS); }
 };
 
 /// Helper class to push and pop a timer marker.  The constructor
 /// pushes a marker, and the destructor pops it.  This is for
 /// convenient timing of regions of code.
 class TimerMarker {
   TimerMarker() = delete;
   TimerMarker(const TimerMarker &) = delete;
@@ skipping 40 matching lines @@
   explicit OstreamLocker(GlobalContext *Ctx) : Ctx(Ctx) { Ctx->lockStr(); }
   ~OstreamLocker() { Ctx->unlockStr(); }
 
 private:
   GlobalContext *const Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEGLOBALCONTEXT_H