Subzero: Don't store std::string objects inside Variable.

src/IceCfgNode.h

 //===- subzero/src/IceCfgNode.h - Control flow graph node -------*- 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 CfgNode class, which represents a single
@@ skipping 17 matching lines @@
 public:
   static CfgNode *create(Cfg *Func, SizeT LabelIndex) {
     return new (Func->allocate<CfgNode>()) CfgNode(Func, LabelIndex);
   }
 
   // Access the label number and name for this node.
   SizeT getIndex() const { return Number; }
   IceString getName() const;
   void setName(const IceString &NewName) {
     // Make sure that the name can only be set once.
-    assert(NameIndex < 0);
+    assert(NameIndex == Cfg::IdentifierIndexInvalid);
     if (!NewName.empty())
-      NameIndex = Func->addNodeName(NewName);
+      NameIndex = Func->addIdentifierName(NewName);
   }
   IceString getAsmName() const {
     return ".L" + Func->getFunctionName() + "$" + getName();
   }
 
   // The HasReturn flag indicates that this node contains a return
   // instruction and therefore needs an epilog.
   void setHasReturn() { HasReturn = true; }
   bool getHasReturn() const { return HasReturn; }
 
@@ skipping 33 matching lines @@
   void contractIfEmpty();
   void doBranchOpt(const CfgNode *NextNode);
   void emit(Cfg *Func) const;
   void emitIAS(Cfg *Func) const;
   void dump(Cfg *Func) const;
 
 private:
   CfgNode(Cfg *Func, SizeT LabelIndex);
   Cfg *const Func;
   const SizeT Number; // label index
-  int32_t NameIndex;  // index into Cfg::NodeNames table
+  Cfg::IdentifierIndexType NameIndex; // index into Cfg::NodeNames table
   bool HasReturn;     // does this block need an epilog?
   bool NeedsPlacement;
   InstNumberT InstCountEstimate; // rough instruction count estimate
   NodeList InEdges;   // in no particular order
   NodeList OutEdges;  // in no particular order
   PhiList Phis;       // unordered set of phi instructions
   InstList Insts;     // ordered list of non-phi instructions
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICECFGNODE_H