[AArch64] Trivial implementation of lower return for the IRTranslator.

llvm-svn: 260574

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -21,6 +21,9 @@
 #include "MCTargetDesc/AArch64AddressingModes.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/CallingConvLower.h"
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+#  include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
+#endif
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
@@ -3392,6 +3395,32 @@ AArch64TargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
   return DAG.getNode(AArch64ISD::RET_FLAG, DL, MVT::Other, RetOps);
 }
 
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+bool AArch64TargetLowering::LowerReturn(MachineIRBuilder &MIRBuilder,
+                                        const Value *Val, unsigned VReg) const {
+  MachineInstr *Return = MIRBuilder.buildInstr(AArch64::RET_ReallyLR);
+  assert(Return && "Unable to build a return instruction?!");
+
+  assert(((Val && VReg) || (!Val && !VReg)) && "Return value without a vreg");
+  if (VReg) {
+    assert(Val->getType()->isIntegerTy() && "Type not supported yet");
+    unsigned Size = Val->getType()->getPrimitiveSizeInBits();
+    assert((Size == 64 || Size == 32) && "Size not supported yet");
+    unsigned ResReg = (Size == 32) ? AArch64::W0 : AArch64::X0;
+    // Set the insertion point to be right before Return.
+    MIRBuilder.setInstr(*Return, /* Before */ true);
+    MachineInstr *Copy =
+        MIRBuilder.buildInstr(TargetOpcode::COPY, ResReg, VReg);
+    (void)Copy;
+    assert(Copy->getNextNode() == Return &&
+           "The insertion did not happen where we expected");
+    MachineInstrBuilder(MIRBuilder.getMF(), Return)
+        .addReg(ResReg, RegState::Implicit);
+  }
+  return true;
+}
+#endif
+
 //===----------------------------------------------------------------------===//
 //  Other Lowering Code
 //===----------------------------------------------------------------------===//

llvm/lib/Target/AArch64/AArch64ISelLowering.h

@@ -452,6 +452,11 @@ private:
                       const SmallVectorImpl<SDValue> &OutVals, SDLoc DL,
                       SelectionDAG &DAG) const override;
 
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+  bool LowerReturn(MachineIRBuilder &MIRBuiler, const Value *Val,
+                   unsigned VReg) const override;
+#endif
+
   SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerDarwinGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;