[AVR][NFC] Merge AVRMCCodeEmitter::emitInstruction into AVRMCCodeEmitter::encodeInstruction.

[jacquesguan]

Summary

The reasons are:
1, AVRMCCodeEmitter::emitInstruction has only one use which is AVRMCCodeEmitter::encodeInstruction, and the parameter STI is not used in this function. I think it might be copied from other target.
2, We do have AVRAsmPrinter::emitInstruction, and it would invoke AVRMCCodeEmitter::encodeInstruction in its calling chain, so if we call AVRMCCodeEmitter::emitInstruction in AVRMCCodeEmitter::encodeInstruction, it would be confusing.

[benshi001]

LGTM。

It would be better if the commit message can be

[AVR][NFC] Merge AVRMCCodeEmitter::emitInstruction into AVRMCCodeEmitter::encodeInstruction

The reasons are
1. ...
2. ...

llvm/lib/Target/AVR/MCTargetDesc/AVRMCCodeEmitter.h

private:
   /// Returns the binary encoding of operand.
   ///
   /// If the machine operand requires relocation, the relocation is recorded
   /// and zero is returned.
   unsigned getMachineOpValue(const MCInst &MI, const MCOperand &MO,
                              SmallVectorImpl<MCFixup> &Fixups,
                              const MCSubtargetInfo &STI) const;
 
-  void emitInstruction(uint64_t Val, unsigned Size, const MCSubtargetInfo &STI,
-                       SmallVectorImpl<char> &CB) const;
-
   void encodeInstruction(const MCInst &MI, SmallVectorImpl<char> &CB,
                          SmallVectorImpl<MCFixup> &Fixups,
                          const MCSubtargetInfo &STI) const override;
 
   AVRMCCodeEmitter(const AVRMCCodeEmitter &) = delete;
   void operator=(const AVRMCCodeEmitter &) = delete;
 
   const MCInstrInfo &MCII;
   MCContext &Ctx;
 };
 
 } // namespace llvm
 
 #endif // LLVM_AVR_CODE_EMITTER_H

llvm/lib/Target/AVR/MCTargetDesc/AVRMCCodeEmitter.cpp

if (MO.isDFPImm())
     return static_cast<unsigned>(bit_cast<double>(MO.getDFPImm()));
 
   // MO must be an Expr.
   assert(MO.isExpr());
 
   return getExprOpValue(MO.getExpr(), Fixups, STI);
 }
 
-void AVRMCCodeEmitter::emitInstruction(uint64_t Val, unsigned Size,
-                                       const MCSubtargetInfo &STI,
-                                       SmallVectorImpl<char> &CB) const {
-  size_t WordCount = Size / 2;
-
-  for (int64_t i = WordCount - 1; i >= 0; --i) {
-    uint16_t Word = (Val >> (i * 16)) & 0xFFFF;
-    support::endian::write(CB, Word, support::endianness::little);
-  }
-}
-
 void AVRMCCodeEmitter::encodeInstruction(const MCInst &MI,
                                          SmallVectorImpl<char> &CB,
                                          SmallVectorImpl<MCFixup> &Fixups,
                                          const MCSubtargetInfo &STI) const {
   const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
 
   // Get byte count of instruction
   unsigned Size = Desc.getSize();
 
   assert(Size > 0 && "Instruction size cannot be zero");
 
   uint64_t BinaryOpCode = getBinaryCodeForInstr(MI, Fixups, STI);
-  emitInstruction(BinaryOpCode, Size, STI, CB);
+
+  for (int64_t i = Size / 2 - 1; i >= 0; --i) {
+    uint16_t Word = (BinaryOpCode >> (i * 16)) & 0xFFFF;
+    support::endian::write(CB, Word, support::endianness::little);
+  }
 }
 
 MCCodeEmitter *createAVRMCCodeEmitter(const MCInstrInfo &MCII,
                                       MCContext &Ctx) {
   return new AVRMCCodeEmitter(MCII, Ctx);
 }
 
 #include "AVRGenMCCodeEmitter.inc"
 
 } // end of namespace llvm