Subzero: Convert a few getName() methods to return a const string ref.

src/IceELFSection.h

 //===- subzero/src/IceELFSection.h - Model of ELF sections ------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Representation of ELF sections.
@@ skipping 48 matching lines @@
   SizeT getNumber() const {
     assert(Number != NoSectionNumber);
     return Number;
   }
 
   void setSize(Elf64_Xword sh_size) { Header.sh_size = sh_size; }
   SizeT getCurrentSize() const { return Header.sh_size; }
 
   void setNameStrIndex(Elf64_Word sh_name) { Header.sh_name = sh_name; }
 
-  IceString getName() const { return Name; }
+  const IceString &getName() const { return Name; }
 
   void setLinkNum(Elf64_Word sh_link) { Header.sh_link = sh_link; }
 
   void setInfoNum(Elf64_Word sh_info) { Header.sh_info = sh_info; }
 
   void setFileOffset(Elf64_Off sh_offset) { Header.sh_offset = sh_offset; }
 
   Elf64_Xword getSectionAlign() const { return Header.sh_addralign; }
 
   // Write the section header out with the given streamer.
   template <bool IsELF64> void writeHeader(ELFStreamer &Str);
 
 protected:
   ~ELFSection() {}
 
   // Name of the section in convenient string form (instead of a index
   // into the Section Header String Table, which is not known till later).
-  IceString Name;
+  const IceString Name;
 
   // The fields of the header. May only be partially initialized, but should
   // be fully initialized before writing.
   Elf64_Shdr Header;
 
   // The number of the section after laying out sections.
   SizeT Number;
 };
 
 // Models text/code sections. Code is written out incrementally and the
@@ skipping 251 matching lines @@
       Rel.setSymbolAndType(Symbol->getNumber(), Fixup.kind());
       Str.writeAddrOrOffset<IsELF64>(Rel.r_offset);
       Str.writeELFWord<IsELF64>(Rel.r_info);
     }
   }
 }
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEELFSECTION_H