470 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			470 lines
		
	
	
		
			15 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===-- MSP430ISelDAGToDAG.cpp - A dag to dag inst selector for MSP430 ----===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file defines an instruction selector for the MSP430 target.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "MSP430.h"
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| #include "MSP430TargetMachine.h"
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| #include "llvm/CodeGen/MachineFrameInfo.h"
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| #include "llvm/CodeGen/MachineFunction.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| #include "llvm/CodeGen/MachineRegisterInfo.h"
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| #include "llvm/CodeGen/SelectionDAG.h"
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| #include "llvm/CodeGen/SelectionDAGISel.h"
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| #include "llvm/IR/CallingConv.h"
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| #include "llvm/IR/Constants.h"
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| #include "llvm/IR/DerivedTypes.h"
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| #include "llvm/IR/Function.h"
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| #include "llvm/IR/Intrinsics.h"
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| #include "llvm/Support/Debug.h"
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| #include "llvm/Support/ErrorHandling.h"
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| #include "llvm/Support/raw_ostream.h"
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| #include "llvm/Target/TargetLowering.h"
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| using namespace llvm;
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| 
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| #define DEBUG_TYPE "msp430-isel"
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| 
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| namespace {
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|   struct MSP430ISelAddressMode {
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|     enum {
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|       RegBase,
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|       FrameIndexBase
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|     } BaseType;
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| 
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|     struct {            // This is really a union, discriminated by BaseType!
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|       SDValue Reg;
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|       int FrameIndex;
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|     } Base;
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| 
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|     int16_t Disp;
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|     const GlobalValue *GV;
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|     const Constant *CP;
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|     const BlockAddress *BlockAddr;
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|     const char *ES;
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|     int JT;
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|     unsigned Align;    // CP alignment.
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| 
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|     MSP430ISelAddressMode()
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|       : BaseType(RegBase), Disp(0), GV(nullptr), CP(nullptr),
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|         BlockAddr(nullptr), ES(nullptr), JT(-1), Align(0) {
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|     }
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| 
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|     bool hasSymbolicDisplacement() const {
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|       return GV != nullptr || CP != nullptr || ES != nullptr || JT != -1;
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|     }
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| 
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|     void dump() {
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|       errs() << "MSP430ISelAddressMode " << this << '\n';
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|       if (BaseType == RegBase && Base.Reg.getNode() != nullptr) {
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|         errs() << "Base.Reg ";
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|         Base.Reg.getNode()->dump();
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|       } else if (BaseType == FrameIndexBase) {
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|         errs() << " Base.FrameIndex " << Base.FrameIndex << '\n';
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|       }
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|       errs() << " Disp " << Disp << '\n';
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|       if (GV) {
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|         errs() << "GV ";
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|         GV->dump();
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|       } else if (CP) {
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|         errs() << " CP ";
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|         CP->dump();
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|         errs() << " Align" << Align << '\n';
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|       } else if (ES) {
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|         errs() << "ES ";
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|         errs() << ES << '\n';
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|       } else if (JT != -1)
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|         errs() << " JT" << JT << " Align" << Align << '\n';
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|     }
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|   };
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| }
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| 
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| /// MSP430DAGToDAGISel - MSP430 specific code to select MSP430 machine
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| /// instructions for SelectionDAG operations.
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| ///
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| namespace {
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|   class MSP430DAGToDAGISel : public SelectionDAGISel {
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|   public:
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|     MSP430DAGToDAGISel(MSP430TargetMachine &TM, CodeGenOpt::Level OptLevel)
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|         : SelectionDAGISel(TM, OptLevel) {}
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| 
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|     const char *getPassName() const override {
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|       return "MSP430 DAG->DAG Pattern Instruction Selection";
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|     }
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| 
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|     bool MatchAddress(SDValue N, MSP430ISelAddressMode &AM);
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|     bool MatchWrapper(SDValue N, MSP430ISelAddressMode &AM);
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|     bool MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM);
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| 
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|     bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
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|                                       std::vector<SDValue> &OutOps) override;
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| 
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|     // Include the pieces autogenerated from the target description.
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|   #include "MSP430GenDAGISel.inc"
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| 
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|   private:
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|     void Select(SDNode *N) override;
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|     bool tryIndexedLoad(SDNode *Op);
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|     bool tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2, unsigned Opc8,
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|                          unsigned Opc16);
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| 
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|     bool SelectAddr(SDValue Addr, SDValue &Base, SDValue &Disp);
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|   };
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| }  // end anonymous namespace
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| 
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| /// createMSP430ISelDag - This pass converts a legalized DAG into a
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| /// MSP430-specific DAG, ready for instruction scheduling.
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| ///
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| FunctionPass *llvm::createMSP430ISelDag(MSP430TargetMachine &TM,
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|                                         CodeGenOpt::Level OptLevel) {
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|   return new MSP430DAGToDAGISel(TM, OptLevel);
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| }
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| 
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| 
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| /// MatchWrapper - Try to match MSP430ISD::Wrapper node into an addressing mode.
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| /// These wrap things that will resolve down into a symbol reference.  If no
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| /// match is possible, this returns true, otherwise it returns false.
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| bool MSP430DAGToDAGISel::MatchWrapper(SDValue N, MSP430ISelAddressMode &AM) {
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|   // If the addressing mode already has a symbol as the displacement, we can
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|   // never match another symbol.
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|   if (AM.hasSymbolicDisplacement())
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|     return true;
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| 
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|   SDValue N0 = N.getOperand(0);
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| 
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|   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
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|     AM.GV = G->getGlobal();
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|     AM.Disp += G->getOffset();
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|     //AM.SymbolFlags = G->getTargetFlags();
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|   } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
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|     AM.CP = CP->getConstVal();
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|     AM.Align = CP->getAlignment();
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|     AM.Disp += CP->getOffset();
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|     //AM.SymbolFlags = CP->getTargetFlags();
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|   } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
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|     AM.ES = S->getSymbol();
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|     //AM.SymbolFlags = S->getTargetFlags();
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|   } else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
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|     AM.JT = J->getIndex();
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|     //AM.SymbolFlags = J->getTargetFlags();
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|   } else {
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|     AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress();
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|     //AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags();
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|   }
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|   return false;
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| }
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| 
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| /// MatchAddressBase - Helper for MatchAddress. Add the specified node to the
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| /// specified addressing mode without any further recursion.
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| bool MSP430DAGToDAGISel::MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM) {
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|   // Is the base register already occupied?
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|   if (AM.BaseType != MSP430ISelAddressMode::RegBase || AM.Base.Reg.getNode()) {
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|     // If so, we cannot select it.
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|     return true;
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|   }
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| 
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|   // Default, generate it as a register.
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|   AM.BaseType = MSP430ISelAddressMode::RegBase;
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|   AM.Base.Reg = N;
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|   return false;
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| }
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| 
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| bool MSP430DAGToDAGISel::MatchAddress(SDValue N, MSP430ISelAddressMode &AM) {
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|   DEBUG(errs() << "MatchAddress: "; AM.dump());
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| 
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|   switch (N.getOpcode()) {
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|   default: break;
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|   case ISD::Constant: {
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|     uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
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|     AM.Disp += Val;
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|     return false;
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|   }
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| 
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|   case MSP430ISD::Wrapper:
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|     if (!MatchWrapper(N, AM))
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|       return false;
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|     break;
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| 
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|   case ISD::FrameIndex:
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|     if (AM.BaseType == MSP430ISelAddressMode::RegBase
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|         && AM.Base.Reg.getNode() == nullptr) {
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|       AM.BaseType = MSP430ISelAddressMode::FrameIndexBase;
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|       AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
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|       return false;
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|     }
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|     break;
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| 
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|   case ISD::ADD: {
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|     MSP430ISelAddressMode Backup = AM;
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|     if (!MatchAddress(N.getNode()->getOperand(0), AM) &&
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|         !MatchAddress(N.getNode()->getOperand(1), AM))
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|       return false;
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|     AM = Backup;
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|     if (!MatchAddress(N.getNode()->getOperand(1), AM) &&
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|         !MatchAddress(N.getNode()->getOperand(0), AM))
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|       return false;
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|     AM = Backup;
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| 
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|     break;
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|   }
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| 
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|   case ISD::OR:
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|     // Handle "X | C" as "X + C" iff X is known to have C bits clear.
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|     if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
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|       MSP430ISelAddressMode Backup = AM;
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|       uint64_t Offset = CN->getSExtValue();
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|       // Start with the LHS as an addr mode.
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|       if (!MatchAddress(N.getOperand(0), AM) &&
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|           // Address could not have picked a GV address for the displacement.
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|           AM.GV == nullptr &&
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|           // Check to see if the LHS & C is zero.
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|           CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
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|         AM.Disp += Offset;
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|         return false;
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|       }
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|       AM = Backup;
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|     }
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|     break;
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|   }
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| 
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|   return MatchAddressBase(N, AM);
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| }
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| 
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| /// SelectAddr - returns true if it is able pattern match an addressing mode.
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| /// It returns the operands which make up the maximal addressing mode it can
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| /// match by reference.
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| bool MSP430DAGToDAGISel::SelectAddr(SDValue N,
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|                                     SDValue &Base, SDValue &Disp) {
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|   MSP430ISelAddressMode AM;
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| 
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|   if (MatchAddress(N, AM))
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|     return false;
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| 
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|   EVT VT = N.getValueType();
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|   if (AM.BaseType == MSP430ISelAddressMode::RegBase) {
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|     if (!AM.Base.Reg.getNode())
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|       AM.Base.Reg = CurDAG->getRegister(0, VT);
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|   }
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| 
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|   Base = (AM.BaseType == MSP430ISelAddressMode::FrameIndexBase)
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|              ? CurDAG->getTargetFrameIndex(
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|                    AM.Base.FrameIndex,
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|                    getTargetLowering()->getPointerTy(CurDAG->getDataLayout()))
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|              : AM.Base.Reg;
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| 
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|   if (AM.GV)
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|     Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(N),
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|                                           MVT::i16, AM.Disp,
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|                                           0/*AM.SymbolFlags*/);
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|   else if (AM.CP)
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|     Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i16,
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|                                          AM.Align, AM.Disp, 0/*AM.SymbolFlags*/);
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|   else if (AM.ES)
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|     Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i16, 0/*AM.SymbolFlags*/);
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|   else if (AM.JT != -1)
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|     Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i16, 0/*AM.SymbolFlags*/);
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|   else if (AM.BlockAddr)
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|     Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, 0,
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|                                          0/*AM.SymbolFlags*/);
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|   else
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|     Disp = CurDAG->getTargetConstant(AM.Disp, SDLoc(N), MVT::i16);
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| 
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|   return true;
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| }
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| 
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| bool MSP430DAGToDAGISel::
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| SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
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|                              std::vector<SDValue> &OutOps) {
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|   SDValue Op0, Op1;
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|   switch (ConstraintID) {
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|   default: return true;
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|   case InlineAsm::Constraint_m: // memory
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|     if (!SelectAddr(Op, Op0, Op1))
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|       return true;
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|     break;
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|   }
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| 
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|   OutOps.push_back(Op0);
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|   OutOps.push_back(Op1);
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|   return false;
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| }
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| 
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| static bool isValidIndexedLoad(const LoadSDNode *LD) {
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|   ISD::MemIndexedMode AM = LD->getAddressingMode();
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|   if (AM != ISD::POST_INC || LD->getExtensionType() != ISD::NON_EXTLOAD)
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|     return false;
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| 
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|   EVT VT = LD->getMemoryVT();
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| 
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|   switch (VT.getSimpleVT().SimpleTy) {
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|   case MVT::i8:
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|     // Sanity check
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|     if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 1)
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|       return false;
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| 
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|     break;
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|   case MVT::i16:
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|     // Sanity check
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|     if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 2)
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|       return false;
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| 
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|     break;
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|   default:
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|     return false;
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|   }
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| 
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|   return true;
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| }
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| 
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| bool MSP430DAGToDAGISel::tryIndexedLoad(SDNode *N) {
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|   LoadSDNode *LD = cast<LoadSDNode>(N);
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|   if (!isValidIndexedLoad(LD))
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|     return false;
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| 
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|   MVT VT = LD->getMemoryVT().getSimpleVT();
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| 
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|   unsigned Opcode = 0;
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|   switch (VT.SimpleTy) {
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|   case MVT::i8:
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|     Opcode = MSP430::MOV8rm_POST;
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|     break;
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|   case MVT::i16:
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|     Opcode = MSP430::MOV16rm_POST;
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|     break;
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|   default:
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|     return false;
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|   }
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| 
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|   ReplaceNode(N,
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|               CurDAG->getMachineNode(Opcode, SDLoc(N), VT, MVT::i16, MVT::Other,
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|                                      LD->getBasePtr(), LD->getChain()));
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|   return true;
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| }
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| 
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| bool MSP430DAGToDAGISel::tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2,
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|                                          unsigned Opc8, unsigned Opc16) {
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|   if (N1.getOpcode() == ISD::LOAD &&
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|       N1.hasOneUse() &&
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|       IsLegalToFold(N1, Op, Op, OptLevel)) {
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|     LoadSDNode *LD = cast<LoadSDNode>(N1);
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|     if (!isValidIndexedLoad(LD))
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|       return false;
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| 
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|     MVT VT = LD->getMemoryVT().getSimpleVT();
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|     unsigned Opc = (VT == MVT::i16 ? Opc16 : Opc8);
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|     MachineSDNode::mmo_iterator MemRefs0 = MF->allocateMemRefsArray(1);
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|     MemRefs0[0] = cast<MemSDNode>(N1)->getMemOperand();
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|     SDValue Ops0[] = { N2, LD->getBasePtr(), LD->getChain() };
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|     SDNode *ResNode =
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|       CurDAG->SelectNodeTo(Op, Opc, VT, MVT::i16, MVT::Other, Ops0);
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|     cast<MachineSDNode>(ResNode)->setMemRefs(MemRefs0, MemRefs0 + 1);
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|     // Transfer chain.
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|     ReplaceUses(SDValue(N1.getNode(), 2), SDValue(ResNode, 2));
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|     // Transfer writeback.
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|     ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 1));
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|     return true;
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|   }
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| 
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|   return false;
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| }
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| 
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| 
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| void MSP430DAGToDAGISel::Select(SDNode *Node) {
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|   SDLoc dl(Node);
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| 
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|   // Dump information about the Node being selected
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|   DEBUG(errs() << "Selecting: ");
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|   DEBUG(Node->dump(CurDAG));
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|   DEBUG(errs() << "\n");
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| 
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|   // If we have a custom node, we already have selected!
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|   if (Node->isMachineOpcode()) {
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|     DEBUG(errs() << "== ";
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|           Node->dump(CurDAG);
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|           errs() << "\n");
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|     Node->setNodeId(-1);
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|     return;
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|   }
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| 
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|   // Few custom selection stuff.
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|   switch (Node->getOpcode()) {
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|   default: break;
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|   case ISD::FrameIndex: {
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|     assert(Node->getValueType(0) == MVT::i16);
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|     int FI = cast<FrameIndexSDNode>(Node)->getIndex();
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|     SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16);
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|     if (Node->hasOneUse()) {
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|       CurDAG->SelectNodeTo(Node, MSP430::ADD16ri, MVT::i16, TFI,
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|                            CurDAG->getTargetConstant(0, dl, MVT::i16));
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|       return;
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|     }
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|     ReplaceNode(Node, CurDAG->getMachineNode(
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|                           MSP430::ADD16ri, dl, MVT::i16, TFI,
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|                           CurDAG->getTargetConstant(0, dl, MVT::i16)));
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|     return;
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|   }
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|   case ISD::LOAD:
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|     if (tryIndexedLoad(Node))
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|       return;
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|     // Other cases are autogenerated.
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|     break;
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|   case ISD::ADD:
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|     if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
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|                         MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
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|       return;
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|     else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
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|                              MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
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|       return;
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| 
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|     // Other cases are autogenerated.
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|     break;
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|   case ISD::SUB:
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|     if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
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|                         MSP430::SUB8rm_POST, MSP430::SUB16rm_POST))
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|       return;
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| 
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|     // Other cases are autogenerated.
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|     break;
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|   case ISD::AND:
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|     if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
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|                         MSP430::AND8rm_POST, MSP430::AND16rm_POST))
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|       return;
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|     else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
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|                              MSP430::AND8rm_POST, MSP430::AND16rm_POST))
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|       return;
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| 
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|     // Other cases are autogenerated.
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|     break;
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|   case ISD::OR:
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|     if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
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|                         MSP430::OR8rm_POST, MSP430::OR16rm_POST))
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|       return;
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|     else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
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|                              MSP430::OR8rm_POST, MSP430::OR16rm_POST))
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|       return;
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| 
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|     // Other cases are autogenerated.
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|     break;
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|   case ISD::XOR:
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|     if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
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|                         MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
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|       return;
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|     else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
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|                              MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
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|       return;
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| 
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|     // Other cases are autogenerated.
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|     break;
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|   }
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| 
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|   // Select the default instruction
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|   SelectCode(Node);
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| }
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