Subzero: Improve class definition hygiene.

src/PNaClTranslator.h

 //===- subzero/src/PNaClTranslator.h - ICE from bitcode ---------*- 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 PNaCl bitcode file to ICE, to machine code
 // translator.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_PNACLTRANSLATOR_H
 #define SUBZERO_SRC_PNACLTRANSLATOR_H
 
 #include <string>
 
 #include "IceTranslator.h"
 
 namespace llvm {
 class MemoryBuffer;
 } // end of namespace llvm
 
 namespace Ice {
 
 class PNaClTranslator : public Translator {
+  PNaClTranslator() = delete;
   PNaClTranslator(const PNaClTranslator &) = delete;
   PNaClTranslator &operator=(const PNaClTranslator &) = delete;
 
 public:
-  PNaClTranslator(GlobalContext *Ctx) : Translator(Ctx) {}
+  explicit PNaClTranslator(GlobalContext *Ctx) : Translator(Ctx) {}
 
   // Reads the PNaCl bitcode file and translates to ICE, which is then
   // converted to machine code. Sets ErrorStatus to 1 if any errors
   // occurred.
   void translate(const std::string &IRFilename);
 
   // Reads MemBuf, assuming it is the PNaCl bitcode contents of IRFilename.
   void translateBuffer(const std::string &IRFilename,
                        llvm::MemoryBuffer *MemBuf);
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_PNACLTRANSLATOR_H