1 //===-- CSKYISelLowering.cpp - CSKY DAG Lowering Implementation  ----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the interfaces that CSKY uses to lower LLVM code into a
10 // selection DAG.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_CSKY_CSKYISELLOWERING_H
15 #define LLVM_LIB_TARGET_CSKY_CSKYISELLOWERING_H
16 
17 #include "MCTargetDesc/CSKYBaseInfo.h"
18 #include "llvm/CodeGen/CallingConvLower.h"
19 #include "llvm/CodeGen/TargetLowering.h"
20 
21 namespace llvm {
22 class CSKYSubtarget;
23 
24 namespace CSKYISD {
25 enum NodeType : unsigned {
26   FIRST_NUMBER = ISD::BUILTIN_OP_END,
27   NIE,
28   NIR,
29   RET,
30   CALL,
31   CALLReg,
32   TAIL,
33   TAILReg,
34   LOAD_ADDR,
35   // i32, i32 <-- f64
36   BITCAST_TO_LOHI,
37   // f64 < -- i32, i32
38   BITCAST_FROM_LOHI,
39 };
40 }
41 
42 class CSKYTargetLowering : public TargetLowering {
43   const CSKYSubtarget &Subtarget;
44 
45 public:
46   explicit CSKYTargetLowering(const TargetMachine &TM,
47                               const CSKYSubtarget &STI);
48 
49   SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
50 
51   EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
52                          EVT VT) const override;
53 
54 private:
55   SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
56                                bool IsVarArg,
57                                const SmallVectorImpl<ISD::InputArg> &Ins,
58                                const SDLoc &DL, SelectionDAG &DAG,
59                                SmallVectorImpl<SDValue> &InVals) const override;
60 
61   bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
62                       bool IsVarArg,
63                       const SmallVectorImpl<ISD::OutputArg> &Outs,
64                       LLVMContext &Context) const override;
65 
66   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
67                       const SmallVectorImpl<ISD::OutputArg> &Outs,
68                       const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
69                       SelectionDAG &DAG) const override;
70 
71   SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
72                     SmallVectorImpl<SDValue> &InVals) const override;
73 
74   const char *getTargetNodeName(unsigned Opcode) const override;
75 
76   /// If a physical register, this returns the register that receives the
77   /// exception address on entry to an EH pad.
78   Register
79   getExceptionPointerRegister(const Constant *PersonalityFn) const override;
80 
81   /// If a physical register, this returns the register that receives the
82   /// exception typeid on entry to a landing pad.
83   Register
84   getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
85 
86   bool isSelectSupported(SelectSupportKind Kind) const override {
87     // CSKY does not support scalar condition selects on vectors.
88     return (Kind != ScalarCondVectorVal);
89   }
90 
91   MachineBasicBlock *
92   EmitInstrWithCustomInserter(MachineInstr &MI,
93                               MachineBasicBlock *BB) const override;
94 
95   SDValue getTargetNode(GlobalAddressSDNode *N, SDLoc DL, EVT Ty,
96                         SelectionDAG &DAG, unsigned Flags) const;
97 
98   SDValue getTargetNode(ExternalSymbolSDNode *N, SDLoc DL, EVT Ty,
99                         SelectionDAG &DAG, unsigned Flags) const;
100 
101   SDValue getTargetNode(JumpTableSDNode *N, SDLoc DL, EVT Ty, SelectionDAG &DAG,
102                         unsigned Flags) const;
103 
104   SDValue getTargetNode(BlockAddressSDNode *N, SDLoc DL, EVT Ty,
105                         SelectionDAG &DAG, unsigned Flags) const;
106 
107   SDValue getTargetConstantPoolValue(GlobalAddressSDNode *N, EVT Ty,
108                                      SelectionDAG &DAG, unsigned Flags) const;
109 
110   SDValue getTargetConstantPoolValue(ExternalSymbolSDNode *N, EVT Ty,
111                                      SelectionDAG &DAG, unsigned Flags) const;
112 
113   SDValue getTargetConstantPoolValue(JumpTableSDNode *N, EVT Ty,
114                                      SelectionDAG &DAG, unsigned Flags) const;
115 
116   SDValue getTargetConstantPoolValue(BlockAddressSDNode *N, EVT Ty,
117                                      SelectionDAG &DAG, unsigned Flags) const;
118 
119   template <class NodeTy, bool IsCall = false>
120   SDValue getAddr(NodeTy *N, SelectionDAG &DAG, bool IsLocal = true) const {
121     SDLoc DL(N);
122     EVT Ty = getPointerTy(DAG.getDataLayout());
123 
124     unsigned Flag = CSKYII::MO_None;
125     bool IsPIC = isPositionIndependent();
126 
127     if (IsPIC)
128       Flag = IsLocal  ? CSKYII::MO_GOTOFF
129              : IsCall ? CSKYII::MO_PLT32
130                       : CSKYII::MO_GOT32;
131 
132     SDValue TCPV = getTargetConstantPoolValue(N, Ty, DAG, Flag);
133     SDValue TV = getTargetNode(N, DL, Ty, DAG, Flag);
134     SDValue Addr = DAG.getNode(CSKYISD::LOAD_ADDR, DL, Ty, {TV, TCPV});
135 
136     if (!IsPIC)
137       return Addr;
138 
139     SDValue Result =
140         DAG.getNode(ISD::ADD, DL, Ty, {DAG.getGLOBAL_OFFSET_TABLE(Ty), Addr});
141     if (IsLocal)
142       return Result;
143 
144     return DAG.getLoad(Ty, DL, DAG.getEntryNode(), Result,
145                        MachinePointerInfo::getGOT(DAG.getMachineFunction()));
146   }
147 
148   SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
149   SDValue LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const;
150   SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
151   SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
152   SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
153   SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG) const;
154   SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
155   SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
156 
157   SDValue getStaticTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG,
158                            bool UseGOT) const;
159   SDValue getDynamicTLSAddr(GlobalAddressSDNode *N, SelectionDAG &DAG) const;
160 
161   CCAssignFn *CCAssignFnForCall(CallingConv::ID CC, bool IsVarArg) const;
162   CCAssignFn *CCAssignFnForReturn(CallingConv::ID CC, bool IsVarArg) const;
163 };
164 
165 } // namespace llvm
166 
167 #endif // LLVM_LIB_TARGET_CSKY_CSKYISELLOWERING_H
168