Subzero: Use CFG-local arena allocation for relevant containers.

src/IceConverter.cpp

 //===- subzero/src/IceConverter.cpp - Converts LLVM to Ice  ---------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the LLVM to ICE converter.
@@ skipping 65 matching lines @@
   operator=(const LLVM2ICEFunctionConverter &) = delete;
 
 public:
   LLVM2ICEFunctionConverter(Ice::Converter &Converter)
       : LLVM2ICEConverter(Converter), Func(nullptr) {}
 
   // Caller is expected to delete the returned Ice::Cfg object.
   Ice::Cfg *convertFunction(const Function *F) {
     VarMap.clear();
     NodeMap.clear();
-    Func = new Ice::Cfg(Ctx);
+    Func = Ice::Cfg::create(Ctx);
     Func->setFunctionName(F->getName());
     Func->setReturnType(convertToIceType(F->getReturnType()));
     Func->setInternal(F->hasInternalLinkage());
     Ice::TimerMarker T(Ice::TimerStack::TT_llvmConvert, Func);
 
     // The initial definition/use of each arg is the entry node.
     for (auto ArgI = F->arg_begin(), ArgE = F->arg_end(); ArgI != ArgE;
          ++ArgI) {
       Func->addArg(mapValueToIceVar(ArgI));
     }
@@ skipping 797 matching lines @@
     Cfg *Fcn = FunctionConverter.convertFunction(&I);
     translateFcn(Fcn);
     if (ALLOW_DUMP && Ctx->getFlags().TimeEachFunction)
       Ctx->popTimer(TimerID, StackID);
   }
 
   emitConstants();
 }
 
 } // end of namespace Ice