[Xtensa] Lowering GLobalTLSAddress operation.

Author: andreisfr

llvm/lib/Target/Xtensa/MCTargetDesc/XtensaELFObjectWriter.cpp

@@ -46,10 +46,14 @@ XtensaObjectWriter::~XtensaObjectWriter() {}
 unsigned XtensaObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
                                           const MCFixup &Fixup,
                                           bool IsPCRel) const {
+  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
 
   switch ((unsigned)Fixup.getKind()) {
   case FK_Data_4:
-    return ELF::R_XTENSA_32;
+    if (Modifier == MCSymbolRefExpr::VariantKind::VK_TPOFF)
+      return ELF::R_XTENSA_TLS_TPOFF;
+    else
+      return ELF::R_XTENSA_32;
   default:
     return ELF::R_XTENSA_SLOT0_OP;
   }

llvm/lib/Target/Xtensa/XtensaISelLowering.cpp

@@ -67,7 +67,7 @@ XtensaTargetLowering::XtensaTargetLowering(const TargetMachine &tm,
   setStackPointerRegisterToSaveRestore(Xtensa::SP);
 
   setSchedulingPreference(Sched::RegPressure);
-  
+
   setBooleanContents(ZeroOrOneBooleanContent);
   setBooleanVectorContents(ZeroOrOneBooleanContent);
 
@@ -88,6 +88,7 @@ XtensaTargetLowering::XtensaTargetLowering(const TargetMachine &tm,
   // Handle the various types of symbolic address.
   setOperationAction(ISD::ConstantPool, PtrVT, Custom);
   setOperationAction(ISD::GlobalAddress, PtrVT, Custom);
+  setOperationAction(ISD::GlobalTLSAddress, PtrVT, Custom);
   setOperationAction(ISD::BlockAddress, PtrVT, Custom);
   setOperationAction(ISD::JumpTable, PtrVT, Custom);
 
@@ -1298,6 +1299,44 @@ SDValue XtensaTargetLowering::LowerGlobalAddress(SDValue Op,
   llvm_unreachable("invalid global addresses to lower");
 }
 
+SDValue XtensaTargetLowering::LowerGlobalTLSAddress(GlobalAddressSDNode *GA,
+                                                    SelectionDAG &DAG) const {
+  SDLoc DL(GA);
+  const GlobalValue *GV = GA->getGlobal();
+  EVT PtrVT = getPointerTy(DAG.getDataLayout());
+
+  if (DAG.getTarget().useEmulatedTLS())
+    return LowerToTLSEmulatedModel(GA, DAG);
+
+  TLSModel::Model model = getTargetMachine().getTLSModel(GV);
+
+  if (!Subtarget.hasTHREADPTR()) {
+    llvm_unreachable("only emulated TLS supported");
+  }
+
+  if ((model == TLSModel::LocalExec) || (model == TLSModel::InitialExec)) {
+    auto PtrVt = getPointerTy(DAG.getDataLayout());
+
+    bool Priv = GV->isPrivateLinkage(GV->getLinkage());
+    // Create a constant pool entry for the callee address
+    XtensaConstantPoolValue *CPV = XtensaConstantPoolSymbol::Create(
+        *DAG.getContext(), GV->getName().str().c_str() /* Sym */,
+        0 /* XtensaCLabelIndex */, Priv, XtensaCP::TPOFF);
+
+    // Get the address of the callee into a register
+    SDValue CPAddr = DAG.getTargetConstantPool(CPV, PtrVt, 4);
+    SDValue CPWrap = getAddrPCRel(CPAddr, DAG);
+
+    SDValue TPRegister = DAG.getRegister(Xtensa::THREADPTR, MVT::i32);
+    SDValue ThreadPointer =
+        DAG.getNode(XtensaISD::RUR, DL, MVT::i32, TPRegister);
+    return DAG.getNode(ISD::ADD, DL, PtrVT, ThreadPointer, CPWrap);
+  } else
+    llvm_unreachable("only local-exec and initial-exec TLS mode supported");
+
+  return SDValue();
+}
+
 SDValue XtensaTargetLowering::LowerBlockAddress(BlockAddressSDNode *Node,
                                                 SelectionDAG &DAG) const {
   const BlockAddress *BA = Node->getBlockAddress();
@@ -1629,6 +1668,8 @@ SDValue XtensaTargetLowering::LowerOperation(SDValue Op,
     return LowerSELECT_CC(Op, DAG);
   case ISD::GlobalAddress:
     return LowerGlobalAddress(Op, DAG);
+  case ISD::GlobalTLSAddress:
+    return LowerGlobalTLSAddress(cast<GlobalAddressSDNode>(Op), DAG);
   case ISD::BlockAddress:
     return LowerBlockAddress(cast<BlockAddressSDNode>(Op), DAG);
   case ISD::JumpTable:
@@ -1685,6 +1726,7 @@ const char *XtensaTargetLowering::getTargetNodeName(unsigned Opcode) const {
     OPCODE(MSUB);
     OPCODE(MOVS);
     OPCODE(MOVSP);
+    OPCODE(RUR);
     OPCODE(SHL);
     OPCODE(SRA);
     OPCODE(SRL);

llvm/lib/Target/Xtensa/XtensaISelLowering.h

@@ -63,6 +63,8 @@ enum {
   // WinABI Return
   RETW_FLAG,
 
+  RUR,
+
   // Selects between operand 0 and operand 1.  Operand 2 is the
   // mask of condition-code values for which operand 0 should be
   // chosen over operand 1; it has the same form as BR_CCMASK.
@@ -166,6 +168,8 @@ class XtensaTargetLowering : public TargetLowering {
   SDValue LowerImmediate(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerImmediateFP(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
+  SDValue LowerGlobalTLSAddress(GlobalAddressSDNode *Node,
+                                SelectionDAG &DAG) const;
   SDValue LowerBlockAddress(BlockAddressSDNode *Node, SelectionDAG &DAG) const;
   SDValue LowerJumpTable(JumpTableSDNode *JT, SelectionDAG &DAG) const;
   SDValue LowerConstantPool(ConstantPoolSDNode *CP, SelectionDAG &DAG) const;

llvm/lib/Target/Xtensa/XtensaInstrInfo.td

@@ -684,7 +684,7 @@ def WUR: RRR_Inst<0x00, 0x03, 0x0F, (outs UR:$ur), (ins AR:$t),
 }
 
 def RUR: RRR_Inst<0x00, 0x03, 0x0E, (outs AR:$r), (ins UR:$ur),
-                 "rur\t$r, $ur", []>
+                 "rur\t$r, $ur", [(set AR:$r, (Xtensa_rur UR:$ur))]>
 {
   bits<8> ur;
 

llvm/lib/Target/Xtensa/XtensaOperators.td

@@ -40,6 +40,7 @@ def SDT_XtensaSRC                 : SDTypeProfile<1, 2, [SDTCisVT<0, i32>, SDTCi
                                                          SDTCisVT<2, i32>]>;
 def SDT_XtensaSSL                 : SDTypeProfile<0, 1, [SDTCisVT<0, i32>]>;
 def SDT_XtensaSSR                 : SDTypeProfile<0, 1, [SDTCisVT<0, i32>]>;
+def SDT_XtensaRUR                : SDTypeProfile<1, 1, [SDTCisVT<0, i32>, SDTCisVT<1, i32>]>;
 
 //===----------------------------------------------------------------------===//
 // Node definitions
@@ -97,3 +98,6 @@ def Xtensa_ssr: SDNode<"XtensaISD::SSR", SDT_XtensaSSR, [SDNPOutGlue]>;
 def Xtensa_brjt: SDNode<"XtensaISD::BR_JT", SDT_XtensaBrJT, [SDNPHasChain]>;
 def Xtensa_callw: SDNode<"XtensaISD::CALLW", SDT_XtensaCall,
                         [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue, SDNPVariadic]>;
+
+def Xtensa_rur: SDNode<"XtensaISD::RUR", SDT_XtensaRUR,
+                            [SDNPInGlue]>;