Change to use arena allocation for function-local data in parser.

src/IceCfg.cpp

 //===- subzero/src/IceCfg.cpp - Control flow graph implementation ---------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 25 matching lines @@
 
 Cfg::Cfg(GlobalContext *Ctx, uint32_t SequenceNumber)
     : Ctx(Ctx), SequenceNumber(SequenceNumber),
       VMask(Ctx->getFlags().getVerbose()), NextInstNumber(Inst::NumberInitial),
       Allocator(new ArenaAllocator<>()), Live(nullptr),
       Target(TargetLowering::createLowering(Ctx->getFlags().getTargetArch(),
                                             this)),
       VMetadata(new VariablesMetadata(this)),
       TargetAssembler(TargetLowering::createAssembler(
           Ctx->getFlags().getTargetArch(), this)) {
-  assert(!Ctx->isIRGenerationDisabled() &&
-         "Attempt to build cfg when IR generation disabled");
 }
 
 Cfg::~Cfg() { assert(ICE_TLS_GET_FIELD(CurrentCfg) == nullptr); }
 
 void Cfg::setError(const IceString &Message) {
   HasError = true;
   ErrorMessage = Message;
 }
 
 CfgNode *Cfg::makeNode() {
@@ skipping 703 matching lines @@
     }
   }
   // Print each basic block
   for (CfgNode *Node : Nodes)
     Node->dump(this);
   if (isVerbose(IceV_Instructions))
     Str << "}\n";
 }
 
 } // end of namespace Ice