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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 getScalarShiftAmountTy(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 LowerVASTART(SDValue Op, SelectionDAG &DAG) const;
     96     SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
     97     SDValue getReturnAddressFrameIndex(SelectionDAG &DAG) const;
     98 
     99     TargetLowering::ConstraintType
    100     getConstraintType(const std::string &Constraint) const;
    101     std::pair<unsigned, const TargetRegisterClass*>
    102     getRegForInlineAsmConstraint(const std::string &Constraint, MVT VT) const;
    103 
    104     /// isTruncateFree - Return true if it's free to truncate a value of type
    105     /// Ty1 to type Ty2. e.g. On msp430 it's free to truncate a i16 value in
    106     /// register R15W to i8 by referencing its sub-register R15B.
    107     virtual bool isTruncateFree(Type *Ty1, Type *Ty2) const;
    108     virtual bool isTruncateFree(EVT VT1, EVT VT2) const;
    109 
    110     /// isZExtFree - Return true if any actual instruction that defines a value
    111     /// of type Ty1 implicit zero-extends the value to Ty2 in the result
    112     /// register. This does not necessarily include registers defined in unknown
    113     /// ways, such as incoming arguments, or copies from unknown virtual
    114     /// registers. Also, if isTruncateFree(Ty2, Ty1) is true, this does not
    115     /// necessarily apply to truncate instructions. e.g. on msp430, all
    116     /// instructions that define 8-bit values implicit zero-extend the result
    117     /// out to 16 bits.
    118     virtual bool isZExtFree(Type *Ty1, Type *Ty2) const;
    119     virtual bool isZExtFree(EVT VT1, EVT VT2) const;
    120     virtual bool isZExtFree(SDValue Val, EVT VT2) const;
    121 
    122     MachineBasicBlock* EmitInstrWithCustomInserter(MachineInstr *MI,
    123                                                    MachineBasicBlock *BB) const;
    124     MachineBasicBlock* EmitShiftInstr(MachineInstr *MI,
    125                                       MachineBasicBlock *BB) const;
    126 
    127   private:
    128     SDValue LowerCCCCallTo(SDValue Chain, SDValue Callee,
    129                            CallingConv::ID CallConv, bool isVarArg,
    130                            bool isTailCall,
    131                            const SmallVectorImpl<ISD::OutputArg> &Outs,
    132                            const SmallVectorImpl<SDValue> &OutVals,
    133                            const SmallVectorImpl<ISD::InputArg> &Ins,
    134                            SDLoc dl, SelectionDAG &DAG,
    135                            SmallVectorImpl<SDValue> &InVals) const;
    136 
    137     SDValue LowerCCCArguments(SDValue Chain,
    138                               CallingConv::ID CallConv,
    139                               bool isVarArg,
    140                               const SmallVectorImpl<ISD::InputArg> &Ins,
    141                               SDLoc dl,
    142                               SelectionDAG &DAG,
    143                               SmallVectorImpl<SDValue> &InVals) const;
    144 
    145     SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
    146                             CallingConv::ID CallConv, bool isVarArg,
    147                             const SmallVectorImpl<ISD::InputArg> &Ins,
    148                             SDLoc dl, SelectionDAG &DAG,
    149                             SmallVectorImpl<SDValue> &InVals) const;
    150 
    151     virtual SDValue
    152       LowerFormalArguments(SDValue Chain,
    153                            CallingConv::ID CallConv, bool isVarArg,
    154                            const SmallVectorImpl<ISD::InputArg> &Ins,
    155                            SDLoc dl, SelectionDAG &DAG,
    156                            SmallVectorImpl<SDValue> &InVals) const;
    157     virtual SDValue
    158       LowerCall(TargetLowering::CallLoweringInfo &CLI,
    159                 SmallVectorImpl<SDValue> &InVals) const;
    160 
    161     virtual SDValue
    162       LowerReturn(SDValue Chain,
    163                   CallingConv::ID CallConv, bool isVarArg,
    164                   const SmallVectorImpl<ISD::OutputArg> &Outs,
    165                   const SmallVectorImpl<SDValue> &OutVals,
    166                   SDLoc dl, SelectionDAG &DAG) const;
    167 
    168     virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
    169                                             SDValue &Base,
    170                                             SDValue &Offset,
    171                                             ISD::MemIndexedMode &AM,
    172                                             SelectionDAG &DAG) const;
    173 
    174     const MSP430Subtarget &Subtarget;
    175     const DataLayout *TD;
    176   };
    177 } // namespace llvm
    178 
    179 #endif // LLVM_TARGET_MSP430_ISELLOWERING_H
    180