Implement @llvm.returnaddress. rdar://8015977.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104421 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 27 insertions, 2 deletions

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index d65c969a15..39e75d32c9 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1701,7 +1701,7 @@ ARMTargetLowering::GetF64FormalArgument(CCValAssign &VA, CCValAssign &NextVA,
     RC = ARM::GPRRegisterClass;
 
   // Transform the arguments stored in physical registers into virtual ones.
-  unsigned Reg = MF.addLiveIn(VA.getLocReg(), RC);
+  unsigned Reg = MF.addLiveIn(VA.getLocReg(), RC); 
   SDValue ArgValue = DAG.getCopyFromReg(Root, dl, Reg, MVT::i32);
 
   SDValue ArgValue2;
@@ -2141,9 +2141,34 @@ static SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) {
   return DAG.getNode(ARMISD::CNEG, dl, VT, AbsVal, AbsVal, ARMCC, CCR, Cmp);
 }
 
+SDValue ARMTargetLowering::LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const{
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MFI->setReturnAddressIsTaken(true);
+
+  EVT VT = Op.getValueType();
+  DebugLoc dl = Op.getDebugLoc();
+  unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
+  if (Depth) {
+    SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
+    SDValue Offset = DAG.getConstant(4, MVT::i32);
+    return DAG.getLoad(VT, dl, DAG.getEntryNode(),
+                       DAG.getNode(ISD::ADD, dl, VT, FrameAddr, Offset),
+                       NULL, 0, false, false, 0);
+  }
+
+  // Return LR, which contains the return address. Mark it an implicit live-in.
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+  TargetRegisterClass *RC = AFI->isThumb1OnlyFunction()
+    ? ARM::tGPRRegisterClass : ARM::GPRRegisterClass;
+  unsigned Reg = MF.addLiveIn(ARM::LR, RC); 
+  return DAG.getCopyFromReg(DAG.getEntryNode(), dl, Reg, VT);
+}
+
 SDValue ARMTargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
   MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
   MFI->setFrameAddressIsTaken(true);
+
   EVT VT = Op.getValueType();
   DebugLoc dl = Op.getDebugLoc();  // FIXME probably not meaningful
   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
@@ -3158,7 +3183,7 @@ SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::FP_TO_SINT:
   case ISD::FP_TO_UINT:    return LowerFP_TO_INT(Op, DAG);
   case ISD::FCOPYSIGN:     return LowerFCOPYSIGN(Op, DAG);
-  case ISD::RETURNADDR:    break;
+  case ISD::RETURNADDR:    return LowerRETURNADDR(Op, DAG);
   case ISD::FRAMEADDR:     return LowerFRAMEADDR(Op, DAG);
   case ISD::GLOBAL_OFFSET_TABLE: return LowerGLOBAL_OFFSET_TABLE(Op, DAG);
   case ISD::EH_SJLJ_LONGJMP: return LowerEH_SJLJ_LONGJMP(Op, DAG);