Move lowerGlobal() from target-specific code to emitGlobal() in generic code.

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- 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 TargetLowering, LoweringContext, and
@@ skipping 366 matching lines @@
   TargetDataLowering &operator=(const TargetDataLowering &) = delete;
 
 public:
   static std::unique_ptr<TargetDataLowering> createLowering(GlobalContext *Ctx);
   virtual ~TargetDataLowering();
 
   virtual void lowerGlobals(std::unique_ptr<VariableDeclarationList> Vars) = 0;
   virtual void lowerConstants() = 0;
 
 protected:
+  void emitGlobal(const VariableDeclaration &Var);
+
+  // For now, we assume .long is the right directive for emitting 4 byte
+  // emit global relocations. However, LLVM MIPS usually uses .4byte instead.
+  // Perhaps there is some difference when the location is unaligned.
+  const char *getEmit32Directive() { return ".long"; }
+
   explicit TargetDataLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 // TargetHeaderLowering is used to "lower" the header of an output file.
 // It writes out the target-specific header attributes. E.g., for ARM
 // this writes out the build attributes (float ABI, etc.).
 class TargetHeaderLowering {
   TargetHeaderLowering() = delete;
   TargetHeaderLowering(const TargetHeaderLowering &) = delete;
   TargetHeaderLowering &operator=(const TargetHeaderLowering &) = delete;
 
 public:
   static std::unique_ptr<TargetHeaderLowering>
   createLowering(GlobalContext *Ctx);
   virtual ~TargetHeaderLowering();
 
   virtual void lower() {}
 
 protected:
   explicit TargetHeaderLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H