| //===- MipsCallLowering.cpp -------------------------------------*- C++ -*-===// | 
 | // | 
 | //                     The LLVM Compiler Infrastructure | 
 | // | 
 | // This file is distributed under the University of Illinois Open Source | 
 | // License. See LICENSE.TXT for details. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 | // | 
 | /// \file | 
 | /// This file implements the lowering of LLVM calls to machine code calls for | 
 | /// GlobalISel. | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 |  | 
 | #include "MipsCallLowering.h" | 
 | #include "MipsCCState.h" | 
 | #include "MipsTargetMachine.h" | 
 | #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h" | 
 |  | 
 | using namespace llvm; | 
 |  | 
 | MipsCallLowering::MipsCallLowering(const MipsTargetLowering &TLI) | 
 |     : CallLowering(&TLI) {} | 
 |  | 
 | bool MipsCallLowering::MipsHandler::assign(const CCValAssign &VA, | 
 |                                            unsigned vreg) { | 
 |   if (VA.isRegLoc()) { | 
 |     assignValueToReg(vreg, VA.getLocReg()); | 
 |   } else if (VA.isMemLoc()) { | 
 |     unsigned Size = alignTo(VA.getValVT().getSizeInBits(), 8) / 8; | 
 |     unsigned Offset = VA.getLocMemOffset(); | 
 |     MachinePointerInfo MPO; | 
 |     unsigned StackAddr = getStackAddress(Size, Offset, MPO); | 
 |     assignValueToAddress(vreg, StackAddr, Size, MPO); | 
 |   } else { | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | namespace { | 
 | class IncomingValueHandler : public MipsCallLowering::MipsHandler { | 
 | public: | 
 |   IncomingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI) | 
 |       : MipsHandler(MIRBuilder, MRI) {} | 
 |  | 
 |   bool handle(ArrayRef<CCValAssign> ArgLocs, | 
 |               ArrayRef<CallLowering::ArgInfo> Args); | 
 |  | 
 | private: | 
 |   void assignValueToReg(unsigned ValVReg, unsigned PhysReg) override; | 
 |  | 
 |   unsigned getStackAddress(uint64_t Size, int64_t Offset, | 
 |                            MachinePointerInfo &MPO) override; | 
 |  | 
 |   void assignValueToAddress(unsigned ValVReg, unsigned Addr, uint64_t Size, | 
 |                             MachinePointerInfo &MPO) override; | 
 |  | 
 |   virtual void markPhysRegUsed(unsigned PhysReg) { | 
 |     MIRBuilder.getMBB().addLiveIn(PhysReg); | 
 |   } | 
 |  | 
 |   void buildLoad(unsigned Val, unsigned Addr, uint64_t Size, unsigned Alignment, | 
 |                  MachinePointerInfo &MPO) { | 
 |     MachineMemOperand *MMO = MIRBuilder.getMF().getMachineMemOperand( | 
 |         MPO, MachineMemOperand::MOLoad, Size, Alignment); | 
 |     MIRBuilder.buildLoad(Val, Addr, *MMO); | 
 |   } | 
 | }; | 
 |  | 
 | class CallReturnHandler : public IncomingValueHandler { | 
 | public: | 
 |   CallReturnHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI, | 
 |                     MachineInstrBuilder &MIB) | 
 |       : IncomingValueHandler(MIRBuilder, MRI), MIB(MIB) {} | 
 |  | 
 | private: | 
 |   void markPhysRegUsed(unsigned PhysReg) override { | 
 |     MIB.addDef(PhysReg, RegState::Implicit); | 
 |   } | 
 |  | 
 |   MachineInstrBuilder &MIB; | 
 | }; | 
 |  | 
 | } // end anonymous namespace | 
 |  | 
 | void IncomingValueHandler::assignValueToReg(unsigned ValVReg, | 
 |                                             unsigned PhysReg) { | 
 |   MIRBuilder.buildCopy(ValVReg, PhysReg); | 
 |   markPhysRegUsed(PhysReg); | 
 | } | 
 |  | 
 | unsigned IncomingValueHandler::getStackAddress(uint64_t Size, int64_t Offset, | 
 |                                                MachinePointerInfo &MPO) { | 
 |   MachineFrameInfo &MFI = MIRBuilder.getMF().getFrameInfo(); | 
 |  | 
 |   int FI = MFI.CreateFixedObject(Size, Offset, true); | 
 |   MPO = MachinePointerInfo::getFixedStack(MIRBuilder.getMF(), FI); | 
 |  | 
 |   unsigned AddrReg = MRI.createGenericVirtualRegister(LLT::pointer(0, 32)); | 
 |   MIRBuilder.buildFrameIndex(AddrReg, FI); | 
 |  | 
 |   return AddrReg; | 
 | } | 
 |  | 
 | void IncomingValueHandler::assignValueToAddress(unsigned ValVReg, unsigned Addr, | 
 |                                                 uint64_t Size, | 
 |                                                 MachinePointerInfo &MPO) { | 
 |   // If the value is not extended, a simple load will suffice. | 
 |   buildLoad(ValVReg, Addr, Size, /* Alignment */ 0, MPO); | 
 | } | 
 |  | 
 | bool IncomingValueHandler::handle(ArrayRef<CCValAssign> ArgLocs, | 
 |                                   ArrayRef<CallLowering::ArgInfo> Args) { | 
 |   for (unsigned i = 0, ArgsSize = Args.size(); i < ArgsSize; ++i) { | 
 |     if (!assign(ArgLocs[i], Args[i].Reg)) | 
 |       return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | namespace { | 
 | class OutgoingValueHandler : public MipsCallLowering::MipsHandler { | 
 | public: | 
 |   OutgoingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI, | 
 |                        MachineInstrBuilder &MIB) | 
 |       : MipsHandler(MIRBuilder, MRI), MIB(MIB) {} | 
 |  | 
 |   bool handle(ArrayRef<CCValAssign> ArgLocs, | 
 |               ArrayRef<CallLowering::ArgInfo> Args); | 
 |  | 
 | private: | 
 |   void assignValueToReg(unsigned ValVReg, unsigned PhysReg) override; | 
 |  | 
 |   unsigned getStackAddress(uint64_t Size, int64_t Offset, | 
 |                            MachinePointerInfo &MPO) override; | 
 |  | 
 |   void assignValueToAddress(unsigned ValVReg, unsigned Addr, uint64_t Size, | 
 |                             MachinePointerInfo &MPO) override; | 
 |  | 
 |   MachineInstrBuilder &MIB; | 
 | }; | 
 | } // end anonymous namespace | 
 |  | 
 | void OutgoingValueHandler::assignValueToReg(unsigned ValVReg, | 
 |                                             unsigned PhysReg) { | 
 |   MIRBuilder.buildCopy(PhysReg, ValVReg); | 
 |   MIB.addUse(PhysReg, RegState::Implicit); | 
 | } | 
 |  | 
 | unsigned OutgoingValueHandler::getStackAddress(uint64_t Size, int64_t Offset, | 
 |                                                MachinePointerInfo &MPO) { | 
 |   LLT p0 = LLT::pointer(0, 32); | 
 |   LLT s32 = LLT::scalar(32); | 
 |   unsigned SPReg = MRI.createGenericVirtualRegister(p0); | 
 |   MIRBuilder.buildCopy(SPReg, Mips::SP); | 
 |  | 
 |   unsigned OffsetReg = MRI.createGenericVirtualRegister(s32); | 
 |   MIRBuilder.buildConstant(OffsetReg, Offset); | 
 |  | 
 |   unsigned AddrReg = MRI.createGenericVirtualRegister(p0); | 
 |   MIRBuilder.buildGEP(AddrReg, SPReg, OffsetReg); | 
 |  | 
 |   MPO = MachinePointerInfo::getStack(MIRBuilder.getMF(), Offset); | 
 |   return AddrReg; | 
 | } | 
 |  | 
 | void OutgoingValueHandler::assignValueToAddress(unsigned ValVReg, unsigned Addr, | 
 |                                                 uint64_t Size, | 
 |                                                 MachinePointerInfo &MPO) { | 
 |   MachineMemOperand *MMO = MIRBuilder.getMF().getMachineMemOperand( | 
 |       MPO, MachineMemOperand::MOStore, Size, /* Alignment */ 0); | 
 |   MIRBuilder.buildStore(ValVReg, Addr, *MMO); | 
 | } | 
 |  | 
 | bool OutgoingValueHandler::handle(ArrayRef<CCValAssign> ArgLocs, | 
 |                                   ArrayRef<CallLowering::ArgInfo> Args) { | 
 |   for (unsigned i = 0; i < Args.size(); ++i) { | 
 |     if (!assign(ArgLocs[i], Args[i].Reg)) | 
 |       return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | static bool isSupportedType(Type *T) { | 
 |   if (T->isIntegerTy() && T->getScalarSizeInBits() == 32) | 
 |     return true; | 
 |   if (T->isPointerTy()) | 
 |     return true; | 
 |   return false; | 
 | } | 
 |  | 
 | bool MipsCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder, | 
 |                                    const Value *Val, unsigned VReg) const { | 
 |  | 
 |   MachineInstrBuilder Ret = MIRBuilder.buildInstrNoInsert(Mips::RetRA); | 
 |  | 
 |   if (Val != nullptr) { | 
 |     if (!isSupportedType(Val->getType())) | 
 |       return false; | 
 |  | 
 |     MachineFunction &MF = MIRBuilder.getMF(); | 
 |     const Function &F = MF.getFunction(); | 
 |     const DataLayout &DL = MF.getDataLayout(); | 
 |     const MipsTargetLowering &TLI = *getTLI<MipsTargetLowering>(); | 
 |  | 
 |     SmallVector<ArgInfo, 8> RetInfos; | 
 |     SmallVector<unsigned, 8> OrigArgIndices; | 
 |  | 
 |     ArgInfo ArgRetInfo(VReg, Val->getType()); | 
 |     setArgFlags(ArgRetInfo, AttributeList::ReturnIndex, DL, F); | 
 |     splitToValueTypes(ArgRetInfo, 0, RetInfos, OrigArgIndices); | 
 |  | 
 |     SmallVector<ISD::OutputArg, 8> Outs; | 
 |     subTargetRegTypeForCallingConv( | 
 |         MIRBuilder, RetInfos, OrigArgIndices, | 
 |         [&](ISD::ArgFlagsTy flags, EVT vt, EVT argvt, bool used, | 
 |             unsigned origIdx, unsigned partOffs) { | 
 |           Outs.emplace_back(flags, vt, argvt, used, origIdx, partOffs); | 
 |         }); | 
 |  | 
 |     SmallVector<CCValAssign, 16> ArgLocs; | 
 |     MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, | 
 |                        F.getContext()); | 
 |     CCInfo.AnalyzeReturn(Outs, TLI.CCAssignFnForReturn()); | 
 |  | 
 |     OutgoingValueHandler RetHandler(MIRBuilder, MF.getRegInfo(), Ret); | 
 |     if (!RetHandler.handle(ArgLocs, RetInfos)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   MIRBuilder.insertInstr(Ret); | 
 |   return true; | 
 | } | 
 |  | 
 | bool MipsCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder, | 
 |                                             const Function &F, | 
 |                                             ArrayRef<unsigned> VRegs) const { | 
 |  | 
 |   // Quick exit if there aren't any args. | 
 |   if (F.arg_empty()) | 
 |     return true; | 
 |  | 
 |   if (F.isVarArg()) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   for (auto &Arg : F.args()) { | 
 |     if (!isSupportedType(Arg.getType())) | 
 |       return false; | 
 |   } | 
 |  | 
 |   MachineFunction &MF = MIRBuilder.getMF(); | 
 |   const DataLayout &DL = MF.getDataLayout(); | 
 |   const MipsTargetLowering &TLI = *getTLI<MipsTargetLowering>(); | 
 |  | 
 |   SmallVector<ArgInfo, 8> ArgInfos; | 
 |   SmallVector<unsigned, 8> OrigArgIndices; | 
 |   unsigned i = 0; | 
 |   for (auto &Arg : F.args()) { | 
 |     ArgInfo AInfo(VRegs[i], Arg.getType()); | 
 |     setArgFlags(AInfo, i + AttributeList::FirstArgIndex, DL, F); | 
 |     splitToValueTypes(AInfo, i, ArgInfos, OrigArgIndices); | 
 |     ++i; | 
 |   } | 
 |  | 
 |   SmallVector<ISD::InputArg, 8> Ins; | 
 |   subTargetRegTypeForCallingConv( | 
 |       MIRBuilder, ArgInfos, OrigArgIndices, | 
 |       [&](ISD::ArgFlagsTy flags, EVT vt, EVT argvt, bool used, unsigned origIdx, | 
 |           unsigned partOffs) { | 
 |         Ins.emplace_back(flags, vt, argvt, used, origIdx, partOffs); | 
 |       }); | 
 |  | 
 |   SmallVector<CCValAssign, 16> ArgLocs; | 
 |   MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, | 
 |                      F.getContext()); | 
 |  | 
 |   const MipsTargetMachine &TM = | 
 |       static_cast<const MipsTargetMachine &>(MF.getTarget()); | 
 |   const MipsABIInfo &ABI = TM.getABI(); | 
 |   CCInfo.AllocateStack(ABI.GetCalleeAllocdArgSizeInBytes(F.getCallingConv()), | 
 |                        1); | 
 |   CCInfo.AnalyzeFormalArguments(Ins, TLI.CCAssignFnForCall()); | 
 |  | 
 |   IncomingValueHandler Handler(MIRBuilder, MF.getRegInfo()); | 
 |   if (!Handler.handle(ArgLocs, ArgInfos)) | 
 |     return false; | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool MipsCallLowering::lowerCall(MachineIRBuilder &MIRBuilder, | 
 |                                  CallingConv::ID CallConv, | 
 |                                  const MachineOperand &Callee, | 
 |                                  const ArgInfo &OrigRet, | 
 |                                  ArrayRef<ArgInfo> OrigArgs) const { | 
 |  | 
 |   if (CallConv != CallingConv::C) | 
 |     return false; | 
 |  | 
 |   for (auto &Arg : OrigArgs) { | 
 |     if (!isSupportedType(Arg.Ty)) | 
 |       return false; | 
 |     if (Arg.Flags.isByVal() || Arg.Flags.isSRet()) | 
 |       return false; | 
 |   } | 
 |   if (OrigRet.Reg && !isSupportedType(OrigRet.Ty)) | 
 |     return false; | 
 |  | 
 |   MachineFunction &MF = MIRBuilder.getMF(); | 
 |   const Function &F = MF.getFunction(); | 
 |   const MipsTargetLowering &TLI = *getTLI<MipsTargetLowering>(); | 
 |   const MipsTargetMachine &TM = | 
 |       static_cast<const MipsTargetMachine &>(MF.getTarget()); | 
 |   const MipsABIInfo &ABI = TM.getABI(); | 
 |  | 
 |   MachineInstrBuilder CallSeqStart = | 
 |       MIRBuilder.buildInstr(Mips::ADJCALLSTACKDOWN); | 
 |  | 
 |   // FIXME: Add support for pic calling sequences, long call sequences for O32, | 
 |   //       N32 and N64. First handle the case when Callee.isReg(). | 
 |   if (Callee.isReg()) | 
 |     return false; | 
 |  | 
 |   MachineInstrBuilder MIB = MIRBuilder.buildInstrNoInsert(Mips::JAL); | 
 |   MIB.addDef(Mips::SP, RegState::Implicit); | 
 |   MIB.add(Callee); | 
 |   const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo(); | 
 |   MIB.addRegMask(TRI->getCallPreservedMask(MF, F.getCallingConv())); | 
 |  | 
 |   TargetLowering::ArgListTy FuncOrigArgs; | 
 |   FuncOrigArgs.reserve(OrigArgs.size()); | 
 |  | 
 |   SmallVector<ArgInfo, 8> ArgInfos; | 
 |   SmallVector<unsigned, 8> OrigArgIndices; | 
 |   unsigned i = 0; | 
 |   for (auto &Arg : OrigArgs) { | 
 |  | 
 |     TargetLowering::ArgListEntry Entry; | 
 |     Entry.Ty = Arg.Ty; | 
 |     FuncOrigArgs.push_back(Entry); | 
 |  | 
 |     splitToValueTypes(Arg, i, ArgInfos, OrigArgIndices); | 
 |     ++i; | 
 |   } | 
 |  | 
 |   SmallVector<ISD::OutputArg, 8> Outs; | 
 |   subTargetRegTypeForCallingConv( | 
 |       MIRBuilder, ArgInfos, OrigArgIndices, | 
 |       [&](ISD::ArgFlagsTy flags, EVT vt, EVT argvt, bool used, unsigned origIdx, | 
 |           unsigned partOffs) { | 
 |         Outs.emplace_back(flags, vt, argvt, used, origIdx, partOffs); | 
 |       }); | 
 |  | 
 |   SmallVector<CCValAssign, 8> ArgLocs; | 
 |   MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, | 
 |                      F.getContext()); | 
 |  | 
 |   CCInfo.AllocateStack(ABI.GetCalleeAllocdArgSizeInBytes(CallConv), 1); | 
 |   const char *Call = Callee.isSymbol() ? Callee.getSymbolName() : nullptr; | 
 |   CCInfo.AnalyzeCallOperands(Outs, TLI.CCAssignFnForCall(), FuncOrigArgs, Call); | 
 |  | 
 |   OutgoingValueHandler RetHandler(MIRBuilder, MF.getRegInfo(), MIB); | 
 |   if (!RetHandler.handle(ArgLocs, ArgInfos)) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   unsigned NextStackOffset = CCInfo.getNextStackOffset(); | 
 |   const TargetFrameLowering *TFL = MF.getSubtarget().getFrameLowering(); | 
 |   unsigned StackAlignment = TFL->getStackAlignment(); | 
 |   NextStackOffset = alignTo(NextStackOffset, StackAlignment); | 
 |   CallSeqStart.addImm(NextStackOffset).addImm(0); | 
 |  | 
 |   MIRBuilder.insertInstr(MIB); | 
 |  | 
 |   if (OrigRet.Reg) { | 
 |  | 
 |     ArgInfos.clear(); | 
 |     SmallVector<unsigned, 8> OrigRetIndices; | 
 |  | 
 |     splitToValueTypes(OrigRet, 0, ArgInfos, OrigRetIndices); | 
 |  | 
 |     SmallVector<ISD::InputArg, 8> Ins; | 
 |     subTargetRegTypeForCallingConv( | 
 |         MIRBuilder, ArgInfos, OrigRetIndices, | 
 |         [&](ISD::ArgFlagsTy flags, EVT vt, EVT argvt, bool used, | 
 |             unsigned origIdx, unsigned partOffs) { | 
 |           Ins.emplace_back(flags, vt, argvt, used, origIdx, partOffs); | 
 |         }); | 
 |  | 
 |     SmallVector<CCValAssign, 8> ArgLocs; | 
 |     MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, | 
 |                        F.getContext()); | 
 |  | 
 |     CCInfo.AnalyzeCallResult(Ins, TLI.CCAssignFnForReturn(), OrigRet.Ty, Call); | 
 |  | 
 |     CallReturnHandler Handler(MIRBuilder, MF.getRegInfo(), MIB); | 
 |     if (!Handler.handle(ArgLocs, ArgInfos)) | 
 |       return false; | 
 |   } | 
 |  | 
 |   MIRBuilder.buildInstr(Mips::ADJCALLSTACKUP).addImm(NextStackOffset).addImm(0); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | void MipsCallLowering::subTargetRegTypeForCallingConv( | 
 |     MachineIRBuilder &MIRBuilder, ArrayRef<ArgInfo> Args, | 
 |     ArrayRef<unsigned> OrigArgIndices, const FunTy &PushBack) const { | 
 |   MachineFunction &MF = MIRBuilder.getMF(); | 
 |   const Function &F = MF.getFunction(); | 
 |   const DataLayout &DL = F.getParent()->getDataLayout(); | 
 |   const MipsTargetLowering &TLI = *getTLI<MipsTargetLowering>(); | 
 |  | 
 |   unsigned ArgNo = 0; | 
 |   for (auto &Arg : Args) { | 
 |  | 
 |     EVT VT = TLI.getValueType(DL, Arg.Ty); | 
 |     MVT RegisterVT = TLI.getRegisterTypeForCallingConv(F.getContext(), | 
 |                                                        F.getCallingConv(), VT); | 
 |  | 
 |     ISD::ArgFlagsTy Flags = Arg.Flags; | 
 |     Flags.setOrigAlign(TLI.getABIAlignmentForCallingConv(Arg.Ty, DL)); | 
 |  | 
 |     PushBack(Flags, RegisterVT, VT, true, OrigArgIndices[ArgNo], 0); | 
 |  | 
 |     ++ArgNo; | 
 |   } | 
 | } | 
 |  | 
 | void MipsCallLowering::splitToValueTypes( | 
 |     const ArgInfo &OrigArg, unsigned OriginalIndex, | 
 |     SmallVectorImpl<ArgInfo> &SplitArgs, | 
 |     SmallVectorImpl<unsigned> &SplitArgsOrigIndices) const { | 
 |  | 
 |   // TODO : perform structure and array split. For now we only deal with | 
 |   // types that pass isSupportedType check. | 
 |   SplitArgs.push_back(OrigArg); | 
 |   SplitArgsOrigIndices.push_back(OriginalIndex); | 
 | } |