From 12ad7cd730cb0575a6d03cccd6073af8e9486f3f Mon Sep 17 00:00:00 2001
From: Robert Lytton <robert@xmos.com>
Date: Mon, 6 Jan 2014 14:20:53 +0000
Subject: XCore target: Lower RETURNADDR

Only handles a depth of zero (the same as FRAMEADDR)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198613 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/XCore/XCoreISelLowering.cpp | 27 +++++++++++++++++++++++++--
 lib/Target/XCore/XCoreISelLowering.h   |  1 +
 2 files changed, 26 insertions(+), 2 deletions(-)

(limited to 'lib/Target')

diff --git a/lib/Target/XCore/XCoreISelLowering.cpp b/lib/Target/XCore/XCoreISelLowering.cpp
index c6cbf51202..65568c9654 100644
--- a/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/lib/Target/XCore/XCoreISelLowering.cpp
@@ -212,6 +212,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::ADD:
   case ISD::SUB:                return ExpandADDSUB(Op.getNode(), DAG);
   case ISD::FRAMEADDR:          return LowerFRAMEADDR(Op, DAG);
+  case ISD::RETURNADDR:         return LowerRETURNADDR(Op, DAG);
   case ISD::INIT_TRAMPOLINE:    return LowerINIT_TRAMPOLINE(Op, DAG);
   case ISD::ADJUST_TRAMPOLINE:  return LowerADJUST_TRAMPOLINE(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
@@ -792,17 +793,39 @@ LowerVASTART(SDValue Op, SelectionDAG &DAG) const
 
 SDValue XCoreTargetLowering::LowerFRAMEADDR(SDValue Op,
                                             SelectionDAG &DAG) const {
-  SDLoc dl(Op);
+  // This nodes represent llvm.frameaddress on the DAG.
+  // It takes one operand, the index of the frame address to return.
+  // An index of zero corresponds to the current function's frame address.
+  // An index of one to the parent's frame address, and so on.
   // Depths > 0 not supported yet!
   if (cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() > 0)
     return SDValue();
 
   MachineFunction &MF = DAG.getMachineFunction();
   const TargetRegisterInfo *RegInfo = getTargetMachine().getRegisterInfo();
-  return DAG.getCopyFromReg(DAG.getEntryNode(), dl,
+  return DAG.getCopyFromReg(DAG.getEntryNode(), SDLoc(Op),
                             RegInfo->getFrameRegister(MF), MVT::i32);
 }
 
+SDValue XCoreTargetLowering::
+LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const {
+  // This nodes represent llvm.returnaddress on the DAG.
+  // It takes one operand, the index of the return address to return.
+  // An index of zero corresponds to the current function's return address.
+  // An index of one to the parent's return address, and so on.
+  // Depths > 0 not supported yet!
+  if (cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() > 0)
+    return SDValue();
+
+  MachineFunction &MF = DAG.getMachineFunction();
+  XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
+  int FI = XFI->createLRSpillSlot(MF);
+  SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
+  return DAG.getLoad(getPointerTy(), SDLoc(Op), DAG.getEntryNode(), FIN,
+                     MachinePointerInfo::getFixedStack(FI), false, false,
+                     false, 0);
+}
+
 SDValue XCoreTargetLowering::
 LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const {
   return Op.getOperand(0);
diff --git a/lib/Target/XCore/XCoreISelLowering.h b/lib/Target/XCore/XCoreISelLowering.h
index bc08497b12..a6dd226024 100644
--- a/lib/Target/XCore/XCoreISelLowering.h
+++ b/lib/Target/XCore/XCoreISelLowering.h
@@ -158,6 +158,7 @@ namespace llvm {
     SDValue LowerUMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINIT_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerADJUST_TRAMPOLINE(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
-- 
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