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

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
 // multiple functions.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEGLOBALCONTEXT_H
 #define SUBZERO_SRC_ICEGLOBALCONTEXT_H
 
 #include <memory>
 
-#include "llvm/Support/Allocator.h"
-
 #include "IceDefs.h"
 #include "IceClFlags.h"
 #include "IceELFObjectWriter.h"
 #include "IceIntrinsics.h"
 #include "IceRNG.h"
 #include "IceTimerTree.h"
 #include "IceTypes.h"
 
 namespace Ice {
 
@@ skipping 169 matching lines @@
   void popTimer(TimerIdT ID, TimerStackIdT StackID = TSK_Default);
   void resetTimer(TimerStackIdT StackID);
   void setTimerName(TimerStackIdT StackID, const IceString &NewName);
   void dumpTimers(TimerStackIdT StackID = TSK_Default,
                   bool DumpCumulative = true);
 
 private:
   Ostream *StrDump; // Stream for dumping / diagnostics
   Ostream *StrEmit; // Stream for code emission
 
-  llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 1024 * 1024> Allocator;
+  ArenaAllocator Allocator;
   VerboseMask VMask;
   std::unique_ptr<class ConstantPool> ConstPool;
   Intrinsics IntrinsicsInfo;
   const TargetArch Arch;
   const OptLevel Opt;
   const IceString TestPrefix;
   const ClFlags &Flags;
   bool HasEmittedFirstMethod;
   RandomNumberGenerator RNG;
   std::unique_ptr<ELFObjectWriter> ObjectWriter;
@@ skipping 32 matching lines @@
 
 private:
   TimerIdT ID;
   GlobalContext *const Ctx;
   bool Active;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEGLOBALCONTEXT_H