Subzero: Allow builds with assertions disabled.

src/IceTimerTree.h

 //===- subzero/src/IceTimerTree.h - Pass timer 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 the TimerTree class, which allows flat and
@@ skipping 32 matching lines @@
 
 public:
   TimerStack(const IceString &TopLevelName);
   static TimerIdT getTimerID(const IceString &Name);
   void push(TimerIdT ID);
   void pop(TimerIdT ID);
   void dump(Ostream &Str);
 
 private:
   void update();
-  static double timestamp() {
-    // TODO: Implement in terms of std::chrono for C++11.
-    return llvm::TimeRecord::getCurrentTime(false).getWallTime();
-  }
+  static double timestamp();
   const double FirstTimestamp;
   double LastTimestamp;
   uint64_t StateChangeCount;
   static std::vector<IceString> IDs; // indexed by TimerIdT
   std::vector<TimerTreeNode> Nodes;  // indexed by TTindex
   std::vector<double> LeafTimes;     // indexed by TimerIdT
   TTindex StackTop;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETIMERTREE_H