AArch64: Implement regMaskToRealRegister method

This commit implements `OMR::ARM64::RealRegister::regMaskToRealRegister`.
It also removes unnecessary aarch/codegen/RealRegister.hpp.

Signed-off-by: Akira Saitoh <saiaki@jp.ibm.com>

compiler/aarch64/codegen/OMRRealRegister.cpp

@@ -19,8 +19,25 @@
  * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
  *******************************************************************************/
 
+#include "codegen/CodeGenerator.hpp"
+#include "codegen/Machine.hpp"
 #include "codegen/RealRegister.hpp"
 
+TR::RealRegister *
+OMR::ARM64::RealRegister::regMaskToRealRegister(TR_RegisterMask mask, TR_RegisterKinds rk, TR::CodeGenerator *cg)
+   {
+   RegNum rr;
+
+   int32_t bitPos = TR::RealRegister::getBitPosInMask(mask);
+
+   if (rk == TR_GPR)
+      rr = FirstGPR;
+   else if (rk == TR_FPR)
+      rr = FirstFPR;
+
+   return cg->machine()->getRealRegister(RegNum(rr+bitPos));
+   }
+
 TR_RegisterMask
 OMR::ARM64::RealRegister::getAvailableRegistersMask(TR_RegisterKinds rk)
    {

compiler/aarch64/codegen/OMRRealRegister.hpp

@@ -147,6 +147,15 @@ class OMR_EXTENSIBLE RealRegister : public OMR::RealRegister
     */
    static TR_RegisterMask getAvailableRegistersMask(TR_RegisterKinds rk);
 
+   /**
+    * @brief Returns real register for the passed register mask
+    * @param[in] mask : register mask
+    * @param[in] rk : register kind
+    * @param[in] cg : code generator
+    * @returns real register
+    */
+   static TR::RealRegister *regMaskToRealRegister(TR_RegisterMask mask, TR_RegisterKinds rk, TR::CodeGenerator *cg);
+
    private:
 
    static const uint8_t fullRegBinaryEncodings[NumRegisters];