diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp new file mode 100644 index 00000000000..e6a8067ed95 --- /dev/null +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -0,0 +1,853 @@ +//===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by the LLVM research group and is distributed under +// the University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This implements the SelectionDAGISel class. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "isel" +#include "llvm/CodeGen/SelectionDAGISel.h" +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Function.h" +#include "llvm/Instructions.h" +#include "llvm/Intrinsics.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/SelectionDAG.h" +#include "llvm/CodeGen/SSARegMap.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetFrameInfo.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Support/Debug.h" +#include +#include +using namespace llvm; + +namespace llvm { + //===--------------------------------------------------------------------===// + /// FunctionLoweringInfo - This contains information that is global to a + /// function that is used when lowering a region of the function. + struct FunctionLoweringInfo { + TargetLowering &TLI; + Function &Fn; + MachineFunction &MF; + SSARegMap *RegMap; + + FunctionLoweringInfo(TargetLowering &TLI, Function &Fn,MachineFunction &MF); + + /// MBBMap - A mapping from LLVM basic blocks to their machine code entry. + std::map MBBMap; + + /// ValueMap - Since we emit code for the function a basic block at a time, + /// we must remember which virtual registers hold the values for + /// cross-basic-block values. + std::map ValueMap; + + /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in + /// the entry block. This allows the allocas to be efficiently referenced + /// anywhere in the function. + std::map StaticAllocaMap; + + unsigned MakeReg(MVT::ValueType VT) { + return RegMap->createVirtualRegister(TLI.getRegClassFor(VT)); + } + + unsigned CreateRegForValue(const Value *V) { + MVT::ValueType VT = TLI.getValueType(V->getType()); + // The common case is that we will only create one register for this + // value. If we have that case, create and return the virtual register. + unsigned NV = TLI.getNumElements(VT); + if (NV == 1) return MakeReg(VT); + + // If this value is represented with multiple target registers, make sure + // to create enough consequtive registers of the right (smaller) type. + unsigned NT = VT-1; // Find the type to use. + while (TLI.getNumElements((MVT::ValueType)NT) != 1) + --NT; + + unsigned R = MakeReg((MVT::ValueType)NT); + for (unsigned i = 1; i != NV; ++i) + MakeReg((MVT::ValueType)NT); + return R; + } + + unsigned InitializeRegForValue(const Value *V) { + unsigned &R = ValueMap[V]; + assert(R == 0 && "Already initialized this value register!"); + return R = CreateRegForValue(V); + } + }; +} + +/// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by +/// PHI nodes or outside of the basic block that defines it. +static bool isUsedOutsideOfDefiningBlock(Instruction *I) { + if (isa(I)) return true; + BasicBlock *BB = I->getParent(); + for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI) + if (cast(*UI)->getParent() != BB || isa(*UI)) + return true; + return false; +} + +FunctionLoweringInfo::FunctionLoweringInfo(TargetLowering &tli, + Function &fn, MachineFunction &mf) + : TLI(tli), Fn(fn), MF(mf), RegMap(MF.getSSARegMap()) { + + // Initialize the mapping of values to registers. This is only set up for + // instruction values that are used outside of the block that defines + // them. + for (Function::aiterator AI = Fn.abegin(), E = Fn.aend(); AI != E; ++AI) + InitializeRegForValue(AI); + + Function::iterator BB = Fn.begin(), E = Fn.end(); + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) + if (AllocaInst *AI = dyn_cast(I)) + if (ConstantUInt *CUI = dyn_cast(AI->getArraySize())) { + const Type *Ty = AI->getAllocatedType(); + uint64_t TySize = TLI.getTargetData().getTypeSize(Ty); + unsigned Align = TLI.getTargetData().getTypeAlignment(Ty); + TySize *= CUI->getValue(); // Get total allocated size. + StaticAllocaMap[AI] = + MF.getFrameInfo()->CreateStackObject(TySize, Align); + } + + for (; BB != E; ++BB) + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) + if (!I->use_empty() && isUsedOutsideOfDefiningBlock(I)) + if (!isa(I) || + !StaticAllocaMap.count(cast(I))) + InitializeRegForValue(I); + + // Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This + // also creates the initial PHI MachineInstrs, though none of the input + // operands are populated. + for (Function::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) { + MachineBasicBlock *MBB = new MachineBasicBlock(BB); + MBBMap[BB] = MBB; + MF.getBasicBlockList().push_back(MBB); + + // Create Machine PHI nodes for LLVM PHI nodes, lowering them as + // appropriate. + PHINode *PN; + for (BasicBlock::iterator I = BB->begin(); + (PN = dyn_cast(I)); ++I) { + unsigned NumElements =TLI.getNumElements(TLI.getValueType(PN->getType())); + unsigned PHIReg = ValueMap[PN]; + assert(PHIReg && "PHI node does not have an assigned virtual register!"); + for (unsigned i = 0; i != NumElements; ++i) + BuildMI(MBB, TargetInstrInfo::PHI, PN->getNumOperands(), PHIReg+i); + } + } +} + + + +//===----------------------------------------------------------------------===// +/// SelectionDAGLowering - This is the common target-independent lowering +/// implementation that is parameterized by a TargetLowering object. +/// Also, targets can overload any lowering method. +/// +namespace llvm { +class SelectionDAGLowering { + MachineBasicBlock *CurMBB; + + std::map NodeMap; + +public: + // TLI - This is information that describes the available target features we + // need for lowering. This indicates when operations are unavailable, + // implemented with a libcall, etc. + TargetLowering &TLI; + SelectionDAG &DAG; + const TargetData &TD; + + /// FuncInfo - Information about the function as a whole. + /// + FunctionLoweringInfo &FuncInfo; + + SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli, + FunctionLoweringInfo &funcinfo) + : TLI(tli), DAG(dag), TD(DAG.getTarget().getTargetData()), + FuncInfo(funcinfo) { + } + + void visit(Instruction &I) { visit(I.getOpcode(), I); } + + void visit(unsigned Opcode, User &I) { + switch (Opcode) { + default: assert(0 && "Unknown instruction type encountered!"); + abort(); + // Build the switch statement using the Instruction.def file. +#define HANDLE_INST(NUM, OPCODE, CLASS) \ + case Instruction::OPCODE:return visit##OPCODE((CLASS&)I); +#include "llvm/Instruction.def" + } + } + + void setCurrentBasicBlock(MachineBasicBlock *MBB) { CurMBB = MBB; } + + + SDOperand getIntPtrConstant(uint64_t Val) { + return DAG.getConstant(Val, TLI.getPointerTy()); + } + + SDOperand getValue(const Value *V) { + SDOperand &N = NodeMap[V]; + if (N.Val) return N; + + MVT::ValueType VT = TLI.getValueType(V->getType()); + if (Constant *C = const_cast(dyn_cast(V))) + if (ConstantExpr *CE = dyn_cast(C)) { + visit(CE->getOpcode(), *CE); + assert(N.Val && "visit didn't populate the ValueMap!"); + return N; + } else if (GlobalValue *GV = dyn_cast(C)) { + return N = DAG.getGlobalAddress(GV, VT); + } else if (isa(C)) { + return N = DAG.getConstant(0, TLI.getPointerTy()); + } else if (isa(C)) { + /// FIXME: Implement UNDEFVALUE better. + if (MVT::isInteger(VT)) + return N = DAG.getConstant(0, VT); + else if (MVT::isFloatingPoint(VT)) + return N = DAG.getConstantFP(0, VT); + else + assert(0 && "Unknown value type!"); + + } else if (ConstantFP *CFP = dyn_cast(C)) { + return N = DAG.getConstantFP(CFP->getValue(), VT); + } else { + // Canonicalize all constant ints to be unsigned. + return N = DAG.getConstant(cast(C)->getRawValue(),VT); + } + + if (const AllocaInst *AI = dyn_cast(V)) { + std::map::iterator SI = + FuncInfo.StaticAllocaMap.find(AI); + if (SI != FuncInfo.StaticAllocaMap.end()) + return DAG.getFrameIndex(SI->second, TLI.getPointerTy()); + } + + std::map::const_iterator VMI = + FuncInfo.ValueMap.find(V); + assert(VMI != FuncInfo.ValueMap.end() && "Value not in map!"); + return N = DAG.getCopyFromReg(VMI->second, VT); + } + + const SDOperand &setValue(const Value *V, SDOperand NewN) { + SDOperand &N = NodeMap[V]; + assert(N.Val == 0 && "Already set a value for this node!"); + return N = NewN; + } + + // Terminator instructions. + void visitRet(ReturnInst &I); + void visitBr(BranchInst &I); + void visitUnreachable(UnreachableInst &I) { /* noop */ } + + // These all get lowered before this pass. + void visitSwitch(SwitchInst &I) { assert(0 && "TODO"); } + void visitInvoke(InvokeInst &I) { assert(0 && "TODO"); } + void visitUnwind(UnwindInst &I) { assert(0 && "TODO"); } + + // + void visitBinary(User &I, unsigned Opcode); + void visitAdd(User &I) { visitBinary(I, ISD::ADD); } + void visitSub(User &I) { visitBinary(I, ISD::SUB); } + void visitMul(User &I) { visitBinary(I, ISD::MUL); } + void visitDiv(User &I) { + visitBinary(I, I.getType()->isUnsigned() ? ISD::UDIV : ISD::SDIV); + } + void visitRem(User &I) { + visitBinary(I, I.getType()->isUnsigned() ? ISD::UREM : ISD::SREM); + } + void visitAnd(User &I) { visitBinary(I, ISD::AND); } + void visitOr (User &I) { visitBinary(I, ISD::OR); } + void visitXor(User &I) { visitBinary(I, ISD::XOR); } + void visitShl(User &I) { visitBinary(I, ISD::SHL); } + void visitShr(User &I) { + visitBinary(I, I.getType()->isUnsigned() ? ISD::SRL : ISD::SRA); + } + + void visitSetCC(User &I, ISD::CondCode SignedOpc, ISD::CondCode UnsignedOpc); + void visitSetEQ(User &I) { visitSetCC(I, ISD::SETEQ, ISD::SETEQ); } + void visitSetNE(User &I) { visitSetCC(I, ISD::SETNE, ISD::SETNE); } + void visitSetLE(User &I) { visitSetCC(I, ISD::SETLE, ISD::SETULE); } + void visitSetGE(User &I) { visitSetCC(I, ISD::SETGE, ISD::SETUGE); } + void visitSetLT(User &I) { visitSetCC(I, ISD::SETLT, ISD::SETULT); } + void visitSetGT(User &I) { visitSetCC(I, ISD::SETGT, ISD::SETUGT); } + + void visitGetElementPtr(User &I); + void visitCast(User &I); + void visitSelect(User &I); + // + + void visitMalloc(MallocInst &I); + void visitFree(FreeInst &I); + void visitAlloca(AllocaInst &I); + void visitLoad(LoadInst &I); + void visitStore(StoreInst &I); + void visitPHI(PHINode &I) { } // PHI nodes are handled specially. + void visitCall(CallInst &I); + + // FIXME: These should go through the FunctionLoweringInfo object!!! + void visitVAStart(CallInst &I); + void visitVANext(VANextInst &I); + void visitVAArg(VAArgInst &I); + void visitVAEnd(CallInst &I); + void visitVACopy(CallInst &I); + void visitReturnAddress(CallInst &I); + void visitFrameAddress(CallInst &I); + + void visitMemSet(CallInst &I); + void visitMemCpy(CallInst &I); + void visitMemMove(CallInst &I); + + void visitUserOp1(Instruction &I) { + assert(0 && "UserOp1 should not exist at instruction selection time!"); + abort(); + } + void visitUserOp2(Instruction &I) { + assert(0 && "UserOp2 should not exist at instruction selection time!"); + abort(); + } +}; +} // end namespace llvm + +void SelectionDAGLowering::visitRet(ReturnInst &I) { + if (I.getNumOperands() == 0) { + DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other, DAG.getRoot())); + return; + } + + SDOperand Op1 = getValue(I.getOperand(0)); + switch (Op1.getValueType()) { + default: assert(0 && "Unknown value type!"); + case MVT::i1: + case MVT::i8: + case MVT::i16: + // Extend integer types to 32-bits. + if (I.getOperand(0)->getType()->isSigned()) + Op1 = DAG.getNode(ISD::SIGN_EXTEND, MVT::i32, Op1); + else + Op1 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Op1); + break; + case MVT::f32: + // Extend float to double. + Op1 = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Op1); + break; + case MVT::i32: + case MVT::i64: + case MVT::f64: + break; // No extension needed! + } + + DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other, DAG.getRoot(), Op1)); +} + +void SelectionDAGLowering::visitBr(BranchInst &I) { + // Update machine-CFG edges. + MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[I.getSuccessor(0)]; + CurMBB->addSuccessor(Succ0MBB); + + // Figure out which block is immediately after the current one. + MachineBasicBlock *NextBlock = 0; + MachineFunction::iterator BBI = CurMBB; + if (++BBI != CurMBB->getParent()->end()) + NextBlock = BBI; + + if (I.isUnconditional()) { + // If this is not a fall-through branch, emit the branch. + if (Succ0MBB != NextBlock) + DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, DAG.getRoot(), + DAG.getBasicBlock(Succ0MBB))); + } else { + MachineBasicBlock *Succ1MBB = FuncInfo.MBBMap[I.getSuccessor(1)]; + CurMBB->addSuccessor(Succ1MBB); + + SDOperand Cond = getValue(I.getCondition()); + + if (Succ1MBB == NextBlock) { + // If the condition is false, fall through. This means we should branch + // if the condition is true to Succ #0. + DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, DAG.getRoot(), + Cond, DAG.getBasicBlock(Succ0MBB))); + } else if (Succ0MBB == NextBlock) { + // If the condition is true, fall through. This means we should branch if + // the condition is false to Succ #1. Invert the condition first. + SDOperand True = DAG.getConstant(1, Cond.getValueType()); + Cond = DAG.getNode(ISD::XOR, Cond.getValueType(), Cond, True); + DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, DAG.getRoot(), + Cond, DAG.getBasicBlock(Succ1MBB))); + } else { + // Neither edge is a fall through. If the comparison is true, jump to + // Succ#0, otherwise branch unconditionally to succ #1. + DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, DAG.getRoot(), + Cond, DAG.getBasicBlock(Succ0MBB))); + DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, DAG.getRoot(), + DAG.getBasicBlock(Succ1MBB))); + } + } +} + +void SelectionDAGLowering::visitBinary(User &I, unsigned Opcode) { + SDOperand Op1 = getValue(I.getOperand(0)); + SDOperand Op2 = getValue(I.getOperand(1)); + setValue(&I, DAG.getNode(Opcode, Op1.getValueType(), Op1, Op2)); +} + +void SelectionDAGLowering::visitSetCC(User &I,ISD::CondCode SignedOpcode, + ISD::CondCode UnsignedOpcode) { + SDOperand Op1 = getValue(I.getOperand(0)); + SDOperand Op2 = getValue(I.getOperand(1)); + ISD::CondCode Opcode = SignedOpcode; + if (I.getOperand(0)->getType()->isUnsigned()) + Opcode = UnsignedOpcode; + setValue(&I, DAG.getSetCC(Opcode, Op1, Op2)); +} + +void SelectionDAGLowering::visitSelect(User &I) { + SDOperand Cond = getValue(I.getOperand(0)); + SDOperand TrueVal = getValue(I.getOperand(1)); + SDOperand FalseVal = getValue(I.getOperand(2)); + setValue(&I, DAG.getNode(ISD::SELECT, TrueVal.getValueType(), Cond, + TrueVal, FalseVal)); +} + +void SelectionDAGLowering::visitCast(User &I) { + SDOperand N = getValue(I.getOperand(0)); + MVT::ValueType SrcTy = TLI.getValueType(I.getOperand(0)->getType()); + MVT::ValueType DestTy = TLI.getValueType(I.getType()); + + if (N.getValueType() == DestTy) { + setValue(&I, N); // noop cast. + return; + } else if (isInteger(SrcTy) && isInteger(DestTy)) { + if (DestTy < SrcTy) // Truncating cast? + setValue(&I, DAG.getNode(ISD::TRUNCATE, DestTy, N)); + else if (I.getOperand(0)->getType()->isSigned()) + setValue(&I, DAG.getNode(ISD::SIGN_EXTEND, DestTy, N)); + else + setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, DestTy, N)); + return; + } else if (isFloatingPoint(SrcTy) && isFloatingPoint(DestTy)) { + if (DestTy < SrcTy) // Rounding cast? + setValue(&I, DAG.getNode(ISD::FP_ROUND, DestTy, N)); + else + setValue(&I, DAG.getNode(ISD::FP_EXTEND, DestTy, N)); + } else { + // F->I or I->F + // FIXME: implement integer/fp conversions! + assert(0 && "This CAST is not yet implemented!\n"); + } +} + +void SelectionDAGLowering::visitGetElementPtr(User &I) { + SDOperand N = getValue(I.getOperand(0)); + const Type *Ty = I.getOperand(0)->getType(); + const Type *UIntPtrTy = TD.getIntPtrType(); + + for (GetElementPtrInst::op_iterator OI = I.op_begin()+1, E = I.op_end(); + OI != E; ++OI) { + Value *Idx = *OI; + if (const StructType *StTy = dyn_cast (Ty)) { + unsigned Field = cast(Idx)->getValue(); + if (Field) { + // N = N + Offset + uint64_t Offset = TD.getStructLayout(StTy)->MemberOffsets[Field]; + N = DAG.getNode(ISD::ADD, N.getValueType(), N, + getIntPtrConstant(Offset)); + } + Ty = StTy->getElementType(Field); + } else { + Ty = cast(Ty)->getElementType(); + if (!isa(Idx) || !cast(Idx)->isNullValue()) { + // N = N + Idx * ElementSize; + uint64_t ElementSize = TD.getTypeSize(Ty); + SDOperand IdxN = getValue(Idx); + IdxN = DAG.getNode(ISD::MUL, N.getValueType(), IdxN, + getIntPtrConstant(ElementSize)); + N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN); + } + } + } + setValue(&I, N); +} + +void SelectionDAGLowering::visitAlloca(AllocaInst &I) { + // If this is a fixed sized alloca in the entry block of the function, + // allocate it statically on the stack. + if (FuncInfo.StaticAllocaMap.count(&I)) + return; // getValue will auto-populate this. + + const Type *Ty = I.getAllocatedType(); + uint64_t TySize = TLI.getTargetData().getTypeSize(Ty); + unsigned Align = TLI.getTargetData().getTypeAlignment(Ty); + + SDOperand AllocSize = getValue(I.getArraySize()); + + assert(AllocSize.getValueType() == TLI.getPointerTy() && + "FIXME: should extend or truncate to pointer size!"); + + AllocSize = DAG.getNode(ISD::MUL, TLI.getPointerTy(), AllocSize, + getIntPtrConstant(TySize)); + + // Handle alignment. If the requested alignment is less than or equal to the + // stack alignment, ignore it and round the size of the allocation up to the + // stack alignment size. If the size is greater than the stack alignment, we + // note this in the DYNAMIC_STACKALLOC node. + unsigned StackAlign = + TLI.getTargetMachine().getFrameInfo()->getStackAlignment(); + if (Align <= StackAlign) { + Align = 0; + // Add SA-1 to the size. + AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize, + getIntPtrConstant(StackAlign-1)); + // Mask out the low bits for alignment purposes. + AllocSize = DAG.getNode(ISD::AND, AllocSize.getValueType(), AllocSize, + getIntPtrConstant(~(uint64_t)(StackAlign-1))); + } + + SDOperand DSA = DAG.getNode(ISD::DYNAMIC_STACKALLOC, AllocSize.getValueType(), + DAG.getRoot(), AllocSize, + getIntPtrConstant(Align)); + DAG.setRoot(setValue(&I, DSA).getValue(1)); + + // Inform the Frame Information that we have just allocated a variable-sized + // object. + CurMBB->getParent()->getFrameInfo()->CreateVariableSizedObject(); +} + + +void SelectionDAGLowering::visitLoad(LoadInst &I) { + SDOperand Ptr = getValue(I.getOperand(0)); + SDOperand L = DAG.getLoad(TLI.getValueType(I.getType()), DAG.getRoot(), Ptr); + DAG.setRoot(setValue(&I, L).getValue(1)); +} + + +void SelectionDAGLowering::visitStore(StoreInst &I) { + Value *SrcV = I.getOperand(0); + SDOperand Src = getValue(SrcV); + SDOperand Ptr = getValue(I.getOperand(1)); + DAG.setRoot(DAG.getNode(ISD::STORE, MVT::Other, DAG.getRoot(), Src, Ptr)); + return; +} + +void SelectionDAGLowering::visitCall(CallInst &I) { + if (Function *F = I.getCalledFunction()) + switch (F->getIntrinsicID()) { + case 0: break; // Not an intrinsic. + case Intrinsic::vastart: visitVAStart(I); return; + case Intrinsic::vaend: visitVAEnd(I); return; + case Intrinsic::vacopy: visitVACopy(I); return; + case Intrinsic::returnaddress: + visitReturnAddress(I); return; + case Intrinsic::frameaddress: + visitFrameAddress(I); return; + default: + // FIXME: IMPLEMENT THESE. + // readport, writeport, readio, writeio + assert(0 && "This intrinsic is not implemented yet!"); + return; + case Intrinsic::memcpy: visitMemCpy(I); return; + case Intrinsic::memset: visitMemSet(I); return; + case Intrinsic::memmove: visitMemMove(I); return; + + case Intrinsic::isunordered: + setValue(&I, DAG.getSetCC(ISD::SETUO, getValue(I.getOperand(1)), + getValue(I.getOperand(2)))); + return; + } + + SDOperand Callee = getValue(I.getOperand(0)); + std::vector > Args; + + for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) { + Value *Arg = I.getOperand(i); + SDOperand ArgNode = getValue(Arg); + Args.push_back(std::make_pair(ArgNode, Arg->getType())); + } + + SDNode *Result = TLI.LowerCallTo(I.getType(), Callee, Args, DAG); + if (I.getType() != Type::VoidTy) + setValue(&I, SDOperand(Result, 0)); +} + +void SelectionDAGLowering::visitMalloc(MallocInst &I) { + SDOperand Src = getValue(I.getOperand(0)); + + MVT::ValueType IntPtr = TLI.getPointerTy(); + // FIXME: Extend or truncate to the intptr size. + assert(Src.getValueType() == IntPtr && "Need to adjust the amount!"); + + // Scale the source by the type size. + uint64_t ElementSize = TD.getTypeSize(I.getType()->getElementType()); + Src = DAG.getNode(ISD::MUL, Src.getValueType(), + Src, getIntPtrConstant(ElementSize)); + + std::vector > Args; + Args.push_back(std::make_pair(Src, TLI.getTargetData().getIntPtrType())); + SDNode *C = TLI.LowerCallTo(I.getType(), + DAG.getExternalSymbol("malloc", IntPtr), + Args, DAG); + setValue(&I, SDOperand(C, 0)); // Pointers always fit in registers +} + +void SelectionDAGLowering::visitFree(FreeInst &I) { + std::vector > Args; + Args.push_back(std::make_pair(getValue(I.getOperand(0)), + TLI.getTargetData().getIntPtrType())); + MVT::ValueType IntPtr = TLI.getPointerTy(); + TLI.LowerCallTo(Type::VoidTy, DAG.getExternalSymbol("free", IntPtr), + Args, DAG); +} + +void SelectionDAGLowering::visitVAStart(CallInst &I) { + // We have no sane default behavior, just emit a useful error message and bail + // out. + std::cerr << "Variable arguments support not implemented for this target!\n"; + abort(); +} + +void SelectionDAGLowering::visitVANext(VANextInst &I) { + // We have no sane default behavior, just emit a useful error message and bail + // out. + std::cerr << "Variable arguments support not implemented for this target!\n"; + abort(); +} +void SelectionDAGLowering::visitVAArg(VAArgInst &I) { + // We have no sane default behavior, just emit a useful error message and bail + // out. + std::cerr << "Variable arguments support not implemented for this target!\n"; + abort(); +} + +void SelectionDAGLowering::visitVAEnd(CallInst &I) { + // By default, this is a noop. On almost all targets, this is fine. +} + +void SelectionDAGLowering::visitVACopy(CallInst &I) { + // By default, vacopy just does a simple pointer copy. + setValue(&I, getValue(I.getOperand(1))); +} + +void SelectionDAGLowering::visitReturnAddress(CallInst &I) { + // It is always conservatively correct for llvm.returnaddress to return 0. + setValue(&I, getIntPtrConstant(0)); +} + +void SelectionDAGLowering::visitFrameAddress(CallInst &I) { + // It is always conservatively correct for llvm.frameaddress to return 0. + setValue(&I, getIntPtrConstant(0)); +} + + +void SelectionDAGLowering::visitMemSet(CallInst &I) { + MVT::ValueType IntPtr = TLI.getPointerTy(); + const Type *IntPtrTy = TLI.getTargetData().getIntPtrType(); + + // Extend the ubyte argument to be an int value for the call. + SDOperand Val = getValue(I.getOperand(2)); + Val = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Val); + + std::vector > Args; + Args.push_back(std::make_pair(getValue(I.getOperand(1)), IntPtrTy)); + Args.push_back(std::make_pair(Val, Type::IntTy)); + Args.push_back(std::make_pair(getValue(I.getOperand(3)), IntPtrTy)); + + TLI.LowerCallTo(Type::VoidTy, DAG.getExternalSymbol("memset", IntPtr), + Args, DAG); +} + +void SelectionDAGLowering::visitMemCpy(CallInst &I) { + MVT::ValueType IntPtr = TLI.getPointerTy(); + const Type *IntPtrTy = TLI.getTargetData().getIntPtrType(); + + std::vector > Args; + Args.push_back(std::make_pair(getValue(I.getOperand(1)), IntPtrTy)); + Args.push_back(std::make_pair(getValue(I.getOperand(2)), IntPtrTy)); + Args.push_back(std::make_pair(getValue(I.getOperand(3)), IntPtrTy)); + + TLI.LowerCallTo(Type::VoidTy, DAG.getExternalSymbol("memcpy", IntPtr), + Args, DAG); +} + +void SelectionDAGLowering::visitMemMove(CallInst &I) { + MVT::ValueType IntPtr = TLI.getPointerTy(); + const Type *IntPtrTy = TLI.getTargetData().getIntPtrType(); + + std::vector > Args; + Args.push_back(std::make_pair(getValue(I.getOperand(1)), IntPtrTy)); + Args.push_back(std::make_pair(getValue(I.getOperand(2)), IntPtrTy)); + Args.push_back(std::make_pair(getValue(I.getOperand(3)), IntPtrTy)); + + TLI.LowerCallTo(Type::VoidTy, DAG.getExternalSymbol("memmove", IntPtr), + Args, DAG); +} + +unsigned SelectionDAGISel::MakeReg(MVT::ValueType VT) { + return RegMap->createVirtualRegister(TLI.getRegClassFor(VT)); +} + + + +bool SelectionDAGISel::runOnFunction(Function &Fn) { + MachineFunction &MF = MachineFunction::construct(&Fn, TLI.getTargetMachine()); + RegMap = MF.getSSARegMap(); + DEBUG(std::cerr << "\n\n\n=== " << Fn.getName() << "\n"); + + FunctionLoweringInfo FuncInfo(TLI, Fn, MF); + + for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) + SelectBasicBlock(I, MF, FuncInfo); + + return true; +} + + +void SelectionDAGISel::CopyValueToVirtualRegister(SelectionDAGLowering &SDL, + Value *V, unsigned Reg) { + SelectionDAG &DAG = SDL.DAG; + DAG.setRoot(DAG.getCopyToReg(DAG.getRoot(), SDL.getValue(V), Reg)); +} + +void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB, + std::vector > &PHINodesToUpdate, + FunctionLoweringInfo &FuncInfo) { + SelectionDAGLowering SDL(DAG, TLI, FuncInfo); + + // If this is the entry block, emit arguments. + Function *F = LLVMBB->getParent(); + if (LLVMBB == &F->front()) { + // FIXME: If an argument is only used in one basic block, we could directly + // emit it (ONLY) into that block, not emitting the COPY_TO_VREG node. This + // would improve codegen in several cases on X86 by allowing the loads to be + // folded into the user operation. + std::vector Args = TLI.LowerArguments(*LLVMBB->getParent(), DAG); + + unsigned a = 0; + for (Function::aiterator AI = F->abegin(), E = F->aend(); AI != E; ++AI,++a) + if (!AI->use_empty()) { + SDL.setValue(AI, Args[a]); + CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]); + } + } + + BB = FuncInfo.MBBMap[LLVMBB]; + SDL.setCurrentBasicBlock(BB); + + // Lower all of the non-terminator instructions. + for (BasicBlock::iterator I = LLVMBB->begin(), E = --LLVMBB->end(); + I != E; ++I) + SDL.visit(*I); + + // Ensure that all instructions which are used outside of their defining + // blocks are available as virtual registers. + for (BasicBlock::iterator I = LLVMBB->begin(), E = LLVMBB->end(); I != E;++I) + if (!I->use_empty()) { + std::map::iterator VMI = + FuncInfo.ValueMap.find(I); + if (VMI != FuncInfo.ValueMap.end()) + CopyValueToVirtualRegister(SDL, I, VMI->second); + } + + // Handle PHI nodes in successor blocks. Emit code into the SelectionDAG to + // ensure constants are generated when needed. Remember the virtual registers + // that need to be added to the Machine PHI nodes as input. We cannot just + // directly add them, because expansion might result in multiple MBB's for one + // BB. As such, the start of the BB might correspond to a different MBB than + // the end. + // + + // Emit constants only once even if used by multiple PHI nodes. + std::map ConstantsOut; + + // Check successor nodes PHI nodes that expect a constant to be available from + // this block. + TerminatorInst *TI = LLVMBB->getTerminator(); + for (unsigned succ = 0, e = TI->getNumSuccessors(); succ != e; ++succ) { + BasicBlock *SuccBB = TI->getSuccessor(succ); + MachineBasicBlock::iterator MBBI = FuncInfo.MBBMap[SuccBB]->begin(); + PHINode *PN; + + // At this point we know that there is a 1-1 correspondence between LLVM PHI + // nodes and Machine PHI nodes, but the incoming operands have not been + // emitted yet. + for (BasicBlock::iterator I = SuccBB->begin(); + (PN = dyn_cast(I)); ++I) { + unsigned Reg; + Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB); + if (Constant *C = dyn_cast(PHIOp)) { + unsigned &RegOut = ConstantsOut[C]; + if (RegOut == 0) { + RegOut = FuncInfo.CreateRegForValue(C); + CopyValueToVirtualRegister(SDL, C, RegOut); + } + Reg = RegOut; + } else { + Reg = FuncInfo.ValueMap[PHIOp]; + assert(Reg && "Didn't codegen value into a register!??"); + } + + // Remember that this register needs to added to the machine PHI node as + // the input for this MBB. + unsigned NumElements =TLI.getNumElements(TLI.getValueType(PN->getType())); + for (unsigned i = 0, e = NumElements; i != e; ++i) + PHINodesToUpdate.push_back(std::make_pair(MBBI++, Reg+i)); + } + } + ConstantsOut.clear(); + + // Lower the terminator after the copies are emitted. + SDL.visit(*LLVMBB->getTerminator()); +} + +void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, MachineFunction &MF, + FunctionLoweringInfo &FuncInfo) { + SelectionDAG DAG(TLI.getTargetMachine(), MF); + CurDAG = &DAG; + std::vector > PHINodesToUpdate; + + // First step, lower LLVM code to some DAG. This DAG may use operations and + // types that are not supported by the target. + BuildSelectionDAG(DAG, LLVMBB, PHINodesToUpdate, FuncInfo); + + DEBUG(std::cerr << "Lowered selection DAG:\n"); + DEBUG(DAG.dump()); + + // Second step, hack on the DAG until it only uses operations and types that + // the target supports. + DAG.Legalize(TLI); + + DEBUG(std::cerr << "Legalized selection DAG:\n"); + DEBUG(DAG.dump()); + + // Finally, instruction select all of the operations to machine code, adding + // the code to the MachineBasicBlock. + InstructionSelectBasicBlock(DAG); + + DEBUG(std::cerr << "Selected machine code:\n"); + DEBUG(BB->dump()); + + // Finally, now that we know what the last MBB the LLVM BB expanded is, update + // PHI nodes in successors. + for (unsigned i = 0, e = PHINodesToUpdate.size(); i != e; ++i) { + MachineInstr *PHI = PHINodesToUpdate[i].first; + assert(PHI->getOpcode() == TargetInstrInfo::PHI && + "This is not a machine PHI node that we are updating!"); + PHI->addRegOperand(PHINodesToUpdate[i].second); + PHI->addMachineBasicBlockOperand(BB); + } +}