Add constant blinding/pooling option for X8632 code translation

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.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares aspects of the compilation that persist across
@@ skipping 54 matching lines @@
   // CodeStats collects rudimentary statistics during translation.
   class CodeStats {
     CodeStats(const CodeStats &) = delete;
     CodeStats &operator=(const CodeStats &) = default;
 #define CODESTATS_TABLE                                                        \
   /* dump string, enum value */                                                \
   X("Inst Count  ", InstCount)                                                 \
   X("Regs Saved  ", RegsSaved)                                                 \
   X("Frame Bytes ", FrameByte)                                                 \
   X("Spills      ", NumSpills)                                                 \
-  X("Fills       ", NumFills)
+  X("Fills       ", NumFills)                                                  \
+  X("R/P Imms    ", NumRPImms)
     //#define X(str, tag)
 
   public:
     enum CSTag {
 #define X(str, tag) CS_##tag,
       CODESTATS_TABLE
 #undef X
           CS_NUM
     };
     CodeStats() { reset(); }
@@ skipping 170 matching lines @@
     Tls->StatsCumulative.update(CodeStats::CS_NumSpills);
   }
   void statsUpdateFills() {
     if (!getFlags().getDumpStats())
       return;
     ThreadContext *Tls = ICE_TLS_GET_FIELD(TLS);
     Tls->StatsFunction.update(CodeStats::CS_NumFills);
     Tls->StatsCumulative.update(CodeStats::CS_NumFills);
   }
 
+  // Number of Randomized or Pooled Immediates
+  void statsUpdateRPImms() {
+    if (!getFlags().getDumpStats())
+      return;
+    ThreadContext *Tls = ICE_TLS_GET_FIELD(TLS);
+    Tls->StatsFunction.update(CodeStats::CS_NumRPImms);
+    Tls->StatsCumulative.update(CodeStats::CS_NumRPImms);
+  }
+
   // These are predefined TimerStackIdT values.
   enum TimerStackKind { TSK_Default = 0, TSK_Funcs, TSK_Num };
 
   // newTimerStackID() creates a new TimerStack in the global space.
   // It does not affect any TimerStack objects in TLS.
   TimerStackIdT newTimerStackID(const IceString &Name);
   // dumpTimers() dumps the global timer data.  As such, one probably
   // wants to call mergeTimerStacks() as a prerequisite.
   void dumpTimers(TimerStackIdT StackID = TSK_Default,
                   bool DumpCumulative = true);
@@ skipping 108 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() {
+    if (RandomizationCookie != 0)
+      return RandomizationCookie;

[JF, 2015/06/17 11:29:18]

This technically needs to be an atomic read, though it can be a relaxed atomic
read. This will be a problem when running as a pexe because relaxed atomics are
upgraded to seq_cst.

Could this not be synchronized at all, and instead initialized once before
IceGlobalContext is created?

[qining, 2015/06/17 18:20:36]

Do you mean using std::atomic<int> for the randomization cookie? You are right
that this cookie just needs to be initialized once. Reading it won't cause any
synchronization problem. I'm think if I should initialize it in the constructor
of IceGlobalContext. I always hope to confine this variable in smaller scope.

+    RandomizationCookieLock.lock();
+    while (RandomizationCookie == 0) {
+      RandomNumberGenerator &RNG = getRNG();
+      RandomizationCookie = (uint32_t)RNG.next(
+          (uint64_t)std::numeric_limits<uint32_t>::max() + 1);
+    }
+    RandomizationCookieLock.unlock();
+    return RandomizationCookie;
+  }

[qining, 2015/06/17 04:28:55]

Method to initialize the randomization cookie and get the cookie

+
 private:
   // Try to ensure mutexes are allocated on separate cache lines.
 
   ICE_CACHELINE_BOUNDARY;
   // Managed by getAllocator()
   GlobalLockType AllocLock;
   ArenaAllocator<> Allocator;
 
   ICE_CACHELINE_BOUNDARY;
   // Managed by getConstantPool()
@@ skipping 49 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;

[qining, 2015/06/17 04:28:55]

Move the Randomization cookie to here from TargetX8632.

+
 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