- enable EmuTLS on RiscV.

Index: lib/Target/RISCV/RISCVISelLowering.cpp
--- lib/Target/RISCV/RISCVISelLowering.cpp.orig
+++ lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2847,6 +2847,10 @@ SDValue RISCVTargetLowering::getDynamicTLSAddr(GlobalA
 
 SDValue RISCVTargetLowering::lowerGlobalTLSAddress(SDValue Op,
                                                    SelectionDAG &DAG) const {
+  const GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
+  if (DAG.getTarget().useEmulatedTLS())
+    return LowerToTLSEmulatedModel(GA, DAG);
+
   SDLoc DL(Op);
   EVT Ty = Op.getValueType();
   GlobalAddressSDNode *N = cast<GlobalAddressSDNode>(Op);