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      1 //===-- MSP430ISelLowering.h - MSP430 DAG Lowering Interface ----*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file defines the interfaces that MSP430 uses to lower LLVM code into a
     11 // selection DAG.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_TARGET_MSP430_ISELLOWERING_H
     16 #define LLVM_TARGET_MSP430_ISELLOWERING_H
     17 
     18 #include "MSP430.h"
     19 #include "llvm/CodeGen/SelectionDAG.h"
     20 #include "llvm/Target/TargetLowering.h"
     21 
     22 namespace llvm {
     23   namespace MSP430ISD {
     24     enum {
     25       FIRST_NUMBER = ISD::BUILTIN_OP_END,
     26 
     27       /// Return with a flag operand. Operand 0 is the chain operand.
     28       RET_FLAG,
     29 
     30       /// Same as RET_FLAG, but used for returning from ISRs.
     31       RETI_FLAG,
     32 
     33       /// Y = R{R,L}A X, rotate right (left) arithmetically
     34       RRA, RLA,
     35 
     36       /// Y = RRC X, rotate right via carry
     37       RRC,
     38 
     39       /// CALL - These operations represent an abstract call
     40       /// instruction, which includes a bunch of information.
     41       CALL,
     42 
     43       /// Wrapper - A wrapper node for TargetConstantPool, TargetExternalSymbol,
     44       /// and TargetGlobalAddress.
     45       Wrapper,
     46 
     47       /// CMP - Compare instruction.
     48       CMP,
     49 
     50       /// SetCC - Operand 0 is condition code, and operand 1 is the flag
     51       /// operand produced by a CMP instruction.
     52       SETCC,
     53 
     54       /// MSP430 conditional branches. Operand 0 is the chain operand, operand 1
     55       /// is the block to branch if condition is true, operand 2 is the
     56       /// condition code, and operand 3 is the flag operand produced by a CMP
     57       /// instruction.
     58       BR_CC,
     59 
     60       /// SELECT_CC - Operand 0 and operand 1 are selection variable, operand 3
     61       /// is condition code and operand 4 is flag operand.
     62       SELECT_CC,
     63 
     64       /// SHL, SRA, SRL - Non-constant shifts.
     65       SHL, SRA, SRL
     66     };
     67   }
     68 
     69   class MSP430Subtarget;
     70   class MSP430TargetMachine;
     71 
     72   class MSP430TargetLowering : public TargetLowering {
     73   public:
     74     explicit MSP430TargetLowering(MSP430TargetMachine &TM);
     75 
     76     virtual MVT getShiftAmountTy(EVT LHSTy) const { return MVT::i8; }
     77 
     78     /// LowerOperation - Provide custom lowering hooks for some operations.
     79     virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
     80 
     81     /// getTargetNodeName - This method returns the name of a target specific
     82     /// DAG node.
     83     virtual const char *getTargetNodeName(unsigned Opcode) const;
     84 
     85     SDValue LowerShifts(SDValue Op, SelectionDAG &DAG) const;
     86     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
     87     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
     88     SDValue LowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const;
     89     SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
     90     SDValue LowerSETCC(SDValue Op, SelectionDAG &DAG) const;
     91     SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
     92     SDValue LowerSIGN_EXTEND(SDValue Op, SelectionDAG &DAG) const;
     93     SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
     94     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
     95     SDValue getReturnAddressFrameIndex(SelectionDAG &DAG) const;
     96 
     97     TargetLowering::ConstraintType
     98     getConstraintType(const std::string &Constraint) const;
     99     std::pair<unsigned, const TargetRegisterClass*>
    100     getRegForInlineAsmConstraint(const std::string &Constraint, EVT VT) const;
    101 
    102     /// isTruncateFree - Return true if it's free to truncate a value of type
    103     /// Ty1 to type Ty2. e.g. On msp430 it's free to truncate a i16 value in
    104     /// register R15W to i8 by referencing its sub-register R15B.
    105     virtual bool isTruncateFree(Type *Ty1, Type *Ty2) const;
    106     virtual bool isTruncateFree(EVT VT1, EVT VT2) const;
    107 
    108     /// isZExtFree - Return true if any actual instruction that defines a value
    109     /// of type Ty1 implicit zero-extends the value to Ty2 in the result
    110     /// register. This does not necessarily include registers defined in unknown
    111     /// ways, such as incoming arguments, or copies from unknown virtual
    112     /// registers. Also, if isTruncateFree(Ty2, Ty1) is true, this does not
    113     /// necessarily apply to truncate instructions. e.g. on msp430, all
    114     /// instructions that define 8-bit values implicit zero-extend the result
    115     /// out to 16 bits.
    116     virtual bool isZExtFree(Type *Ty1, Type *Ty2) const;
    117     virtual bool isZExtFree(EVT VT1, EVT VT2) const;
    118 
    119     MachineBasicBlock* EmitInstrWithCustomInserter(MachineInstr *MI,
    120                                                    MachineBasicBlock *BB) const;
    121     MachineBasicBlock* EmitShiftInstr(MachineInstr *MI,
    122                                       MachineBasicBlock *BB) const;
    123 
    124   private:
    125     SDValue LowerCCCCallTo(SDValue Chain, SDValue Callee,
    126                            CallingConv::ID CallConv, bool isVarArg,
    127                            bool isTailCall,
    128                            const SmallVectorImpl<ISD::OutputArg> &Outs,
    129                            const SmallVectorImpl<SDValue> &OutVals,
    130                            const SmallVectorImpl<ISD::InputArg> &Ins,
    131                            DebugLoc dl, SelectionDAG &DAG,
    132                            SmallVectorImpl<SDValue> &InVals) const;
    133 
    134     SDValue LowerCCCArguments(SDValue Chain,
    135                               CallingConv::ID CallConv,
    136                               bool isVarArg,
    137                               const SmallVectorImpl<ISD::InputArg> &Ins,
    138                               DebugLoc dl,
    139                               SelectionDAG &DAG,
    140                               SmallVectorImpl<SDValue> &InVals) const;
    141 
    142     SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
    143                             CallingConv::ID CallConv, bool isVarArg,
    144                             const SmallVectorImpl<ISD::InputArg> &Ins,
    145                             DebugLoc dl, SelectionDAG &DAG,
    146                             SmallVectorImpl<SDValue> &InVals) const;
    147 
    148     virtual SDValue
    149       LowerFormalArguments(SDValue Chain,
    150                            CallingConv::ID CallConv, bool isVarArg,
    151                            const SmallVectorImpl<ISD::InputArg> &Ins,
    152                            DebugLoc dl, SelectionDAG &DAG,
    153                            SmallVectorImpl<SDValue> &InVals) const;
    154     virtual SDValue
    155       LowerCall(SDValue Chain, SDValue Callee, CallingConv::ID CallConv,
    156                 bool isVarArg, bool doesNotRet, bool &isTailCall,
    157                 const SmallVectorImpl<ISD::OutputArg> &Outs,
    158                 const SmallVectorImpl<SDValue> &OutVals,
    159                 const SmallVectorImpl<ISD::InputArg> &Ins,
    160                 DebugLoc dl, SelectionDAG &DAG,
    161                 SmallVectorImpl<SDValue> &InVals) const;
    162 
    163     virtual SDValue
    164       LowerReturn(SDValue Chain,
    165                   CallingConv::ID CallConv, bool isVarArg,
    166                   const SmallVectorImpl<ISD::OutputArg> &Outs,
    167                   const SmallVectorImpl<SDValue> &OutVals,
    168                   DebugLoc dl, SelectionDAG &DAG) const;
    169 
    170     virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
    171                                             SDValue &Base,
    172                                             SDValue &Offset,
    173                                             ISD::MemIndexedMode &AM,
    174                                             SelectionDAG &DAG) const;
    175 
    176     const MSP430Subtarget &Subtarget;
    177     const MSP430TargetMachine &TM;
    178     const TargetData *TD;
    179   };
    180 } // namespace llvm
    181 
    182 #endif // LLVM_TARGET_MSP430_ISELLOWERING_H
    183