Fix symbol table handling in functions.

src/IceOperand.h

 //===- subzero/src/IceOperand.h - High-level operands -----------*- 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 Operand class and its target-independent
@@ skipping 317 matching lines @@
 // have a non-negative RegNum field.
 class Variable : public Operand {
 public:
   static Variable *create(Cfg *Func, Type Ty, const CfgNode *Node, SizeT Index,
                           const IceString &Name) {
     return new (Func->allocate<Variable>()) Variable(Ty, Node, Index, Name);
   }
 
   SizeT getIndex() const { return Number; }
   IceString getName() const;
+  void setName(IceString &NewName) {
+    // Make sure that the name can only be set once.
+    assert(Name.empty());
+    Name = NewName;
+  }
 
   Inst *getDefinition() const { return DefInst; }
   void setDefinition(Inst *Inst, const CfgNode *Node);
   void replaceDefinition(Inst *Inst, const CfgNode *Node);
 
   const CfgNode *getLocalUseNode() const { return DefNode; }
   bool isMultiblockLife() const { return (DefNode == NULL); }
   void setUse(const Inst *Inst, const CfgNode *Node);
 
   bool getIsArg() const { return IsArgument; }
@@ skipping 72 matching lines @@
     Vars = VarsReal;
     Vars[0] = this;
     NumVars = 1;
   }
   Variable(const Variable &) LLVM_DELETED_FUNCTION;
   Variable &operator=(const Variable &) LLVM_DELETED_FUNCTION;
   // Number is unique across all variables, and is used as a
   // (bit)vector index for liveness analysis.
   const SizeT Number;
   // Name is optional.
-  const IceString Name;
+  IceString Name;
   // DefInst is the instruction that produces this variable as its
   // dest.
   Inst *DefInst;
   // DefNode is the node where this variable was produced, and is
   // reset to NULL if it is used outside that node.  This is used for
   // detecting isMultiblockLife().  TODO: Collapse this to a single
   // bit and use a separate pass to calculate the values across the
   // Cfg.  This saves space in the Variable, and removes the fragility
   // of incrementally computing and maintaining the information.
   const CfgNode *DefNode;
@@ skipping 28 matching lines @@
   Variable *LoVar;
   Variable *HiVar;
   // VarsReal (and Operand::Vars) are set up such that Vars[0] ==
   // this.
   Variable *VarsReal[1];
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEOPERAND_H