[RISCV] Remove unused declarations and getSpecifier. NFC

Remove unused declarations after llvm#132569.
Simplify some code as we no longer use MCSymbolRefExpr::VariantKind.

Author: MaskRay

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

@@ -2104,8 +2104,7 @@ ParseStatus RISCVAsmParser::parsePseudoJumpSymbol(OperandVector &Operands) {
   if (getParser().parseExpression(Res, E))
     return ParseStatus::Failure;
 
-  if (Res->getKind() != MCExpr::ExprKind::SymbolRef ||
-      getSpecifier(cast<MCSymbolRefExpr>(Res)) == RISCVMCExpr::VK_PLTPCREL)
+  if (Res->getKind() != MCExpr::ExprKind::SymbolRef)
     return Error(S, "operand must be a valid jump target");
 
   Res = RISCVMCExpr::create(Res, RISCVMCExpr::VK_CALL, getContext());

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp

@@ -557,10 +557,7 @@ uint64_t RISCVMCCodeEmitter::getImmOpValue(const MCInst &MI, unsigned OpNo,
       FixupKind = RISCV::fixup_riscv_tlsdesc_call;
       break;
     }
-  } else if ((Kind == MCExpr::SymbolRef &&
-              getSpecifier(cast<MCSymbolRefExpr>(Expr)) ==
-                  RISCVMCExpr::VK_None) ||
-             Kind == MCExpr::Binary) {
+  } else if (Kind == MCExpr::SymbolRef || Kind == MCExpr::Binary) {
     // FIXME: Sub kind binary exprs have chance of underflow.
     if (MIFrm == RISCVII::InstFormatJ) {
       FixupKind = RISCV::fixup_riscv_jal;

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCExpr.h

@@ -49,8 +49,6 @@ class RISCVMCExpr : public MCTargetExpr {
   const MCExpr *Expr;
   const Specifier specifier;
 
-  int64_t evaluateAsInt64(int64_t Value) const;
-
   explicit RISCVMCExpr(const MCExpr *Expr, Specifier S)
       : Expr(Expr), specifier(S) {}
 
@@ -77,19 +75,13 @@ class RISCVMCExpr : public MCTargetExpr {
     return getSubExpr()->findAssociatedFragment();
   }
 
-  bool evaluateAsConstant(int64_t &Res) const;
-
   static bool classof(const MCExpr *E) {
     return E->getKind() == MCExpr::Target;
   }
 
   static std::optional<Specifier> getSpecifierForName(StringRef name);
   static StringRef getSpecifierName(Specifier Kind);
 };
-
-static inline RISCVMCExpr::Specifier getSpecifier(const MCSymbolRefExpr *SRE) {
-  return RISCVMCExpr::Specifier(SRE->getKind());
-}
 } // end namespace llvm.
 
 #endif