1 //===-- lib/CodeGen/GlobalISel/CallLowering.cpp - Call lowering -----------===// 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 /// \file 11 /// This file implements some simple delegations needed for call lowering. 12 /// 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/CodeGen/GlobalISel/CallLowering.h" 16 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h" 17 #include "llvm/CodeGen/MachineOperand.h" 18 #include "llvm/CodeGen/MachineRegisterInfo.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/IR/Instructions.h" 21 #include "llvm/IR/Module.h" 22 #include "llvm/Target/TargetLowering.h" 23 24 using namespace llvm; 25 26 bool CallLowering::lowerCall( 27 MachineIRBuilder &MIRBuilder, const CallInst &CI, unsigned ResReg, 28 ArrayRef<unsigned> ArgRegs, std::function<unsigned()> GetCalleeReg) const { 29 auto &DL = CI.getParent()->getParent()->getParent()->getDataLayout(); 30 31 // First step is to marshall all the function's parameters into the correct 32 // physregs and memory locations. Gather the sequence of argument types that 33 // we'll pass to the assigner function. 34 SmallVector<ArgInfo, 8> OrigArgs; 35 unsigned i = 0; 36 unsigned NumFixedArgs = CI.getFunctionType()->getNumParams(); 37 for (auto &Arg : CI.arg_operands()) { 38 ArgInfo OrigArg{ArgRegs[i], Arg->getType(), ISD::ArgFlagsTy{}, 39 i < NumFixedArgs}; 40 setArgFlags(OrigArg, i + 1, DL, CI); 41 OrigArgs.push_back(OrigArg); 42 ++i; 43 } 44 45 MachineOperand Callee = MachineOperand::CreateImm(0); 46 if (Function *F = CI.getCalledFunction()) 47 Callee = MachineOperand::CreateGA(F, 0); 48 else 49 Callee = MachineOperand::CreateReg(GetCalleeReg(), false); 50 51 ArgInfo OrigRet{ResReg, CI.getType(), ISD::ArgFlagsTy{}}; 52 if (!OrigRet.Ty->isVoidTy()) 53 setArgFlags(OrigRet, AttributeSet::ReturnIndex, DL, CI); 54 55 return lowerCall(MIRBuilder, Callee, OrigRet, OrigArgs); 56 } 57 58 template <typename FuncInfoTy> 59 void CallLowering::setArgFlags(CallLowering::ArgInfo &Arg, unsigned OpIdx, 60 const DataLayout &DL, 61 const FuncInfoTy &FuncInfo) const { 62 const AttributeSet &Attrs = FuncInfo.getAttributes(); 63 if (Attrs.hasAttribute(OpIdx, Attribute::ZExt)) 64 Arg.Flags.setZExt(); 65 if (Attrs.hasAttribute(OpIdx, Attribute::SExt)) 66 Arg.Flags.setSExt(); 67 if (Attrs.hasAttribute(OpIdx, Attribute::InReg)) 68 Arg.Flags.setInReg(); 69 if (Attrs.hasAttribute(OpIdx, Attribute::StructRet)) 70 Arg.Flags.setSRet(); 71 if (Attrs.hasAttribute(OpIdx, Attribute::SwiftSelf)) 72 Arg.Flags.setSwiftSelf(); 73 if (Attrs.hasAttribute(OpIdx, Attribute::SwiftError)) 74 Arg.Flags.setSwiftError(); 75 if (Attrs.hasAttribute(OpIdx, Attribute::ByVal)) 76 Arg.Flags.setByVal(); 77 if (Attrs.hasAttribute(OpIdx, Attribute::InAlloca)) 78 Arg.Flags.setInAlloca(); 79 80 if (Arg.Flags.isByVal() || Arg.Flags.isInAlloca()) { 81 Type *ElementTy = cast<PointerType>(Arg.Ty)->getElementType(); 82 Arg.Flags.setByValSize(DL.getTypeAllocSize(ElementTy)); 83 // For ByVal, alignment should be passed from FE. BE will guess if 84 // this info is not there but there are cases it cannot get right. 85 unsigned FrameAlign; 86 if (FuncInfo.getParamAlignment(OpIdx)) 87 FrameAlign = FuncInfo.getParamAlignment(OpIdx); 88 else 89 FrameAlign = getTLI()->getByValTypeAlignment(ElementTy, DL); 90 Arg.Flags.setByValAlign(FrameAlign); 91 } 92 if (Attrs.hasAttribute(OpIdx, Attribute::Nest)) 93 Arg.Flags.setNest(); 94 Arg.Flags.setOrigAlign(DL.getABITypeAlignment(Arg.Ty)); 95 } 96 97 template void 98 CallLowering::setArgFlags<Function>(CallLowering::ArgInfo &Arg, unsigned OpIdx, 99 const DataLayout &DL, 100 const Function &FuncInfo) const; 101 102 template void 103 CallLowering::setArgFlags<CallInst>(CallLowering::ArgInfo &Arg, unsigned OpIdx, 104 const DataLayout &DL, 105 const CallInst &FuncInfo) const; 106 107 bool CallLowering::handleAssignments(MachineIRBuilder &MIRBuilder, 108 ArrayRef<ArgInfo> Args, 109 ValueHandler &Handler) const { 110 MachineFunction &MF = MIRBuilder.getMF(); 111 const Function &F = *MF.getFunction(); 112 const DataLayout &DL = F.getParent()->getDataLayout(); 113 114 SmallVector<CCValAssign, 16> ArgLocs; 115 CCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, F.getContext()); 116 117 unsigned NumArgs = Args.size(); 118 for (unsigned i = 0; i != NumArgs; ++i) { 119 MVT CurVT = MVT::getVT(Args[i].Ty); 120 if (Handler.assignArg(i, CurVT, CurVT, CCValAssign::Full, Args[i], CCInfo)) 121 return false; 122 } 123 124 for (unsigned i = 0, e = Args.size(); i != e; ++i) { 125 CCValAssign &VA = ArgLocs[i]; 126 127 if (VA.isRegLoc()) 128 Handler.assignValueToReg(Args[i].Reg, VA.getLocReg(), VA); 129 else if (VA.isMemLoc()) { 130 unsigned Size = VA.getValVT() == MVT::iPTR 131 ? DL.getPointerSize() 132 : alignTo(VA.getValVT().getSizeInBits(), 8) / 8; 133 unsigned Offset = VA.getLocMemOffset(); 134 MachinePointerInfo MPO; 135 unsigned StackAddr = Handler.getStackAddress(Size, Offset, MPO); 136 Handler.assignValueToAddress(Args[i].Reg, StackAddr, Size, MPO, VA); 137 } else { 138 // FIXME: Support byvals and other weirdness 139 return false; 140 } 141 } 142 return true; 143 } 144 145 unsigned CallLowering::ValueHandler::extendRegister(unsigned ValReg, 146 CCValAssign &VA) { 147 LLT LocTy{VA.getLocVT()}; 148 switch (VA.getLocInfo()) { 149 default: break; 150 case CCValAssign::Full: 151 case CCValAssign::BCvt: 152 // FIXME: bitconverting between vector types may or may not be a 153 // nop in big-endian situations. 154 return ValReg; 155 case CCValAssign::AExt: 156 assert(!VA.getLocVT().isVector() && "unexpected vector extend"); 157 // Otherwise, it's a nop. 158 return ValReg; 159 case CCValAssign::SExt: { 160 unsigned NewReg = MRI.createGenericVirtualRegister(LocTy); 161 MIRBuilder.buildSExt(NewReg, ValReg); 162 return NewReg; 163 } 164 case CCValAssign::ZExt: { 165 unsigned NewReg = MRI.createGenericVirtualRegister(LocTy); 166 MIRBuilder.buildZExt(NewReg, ValReg); 167 return NewReg; 168 } 169 } 170 llvm_unreachable("unable to extend register"); 171 } 172