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llvm-project/llvm/lib/Target/Mips/MipsCallLowering.cpp

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//===- 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/Analysis.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
using namespace llvm;
MipsCallLowering::MipsCallLowering(const MipsTargetLowering &TLI)
: CallLowering(&TLI) {}
bool MipsCallLowering::MipsHandler::assign(unsigned VReg,
const CCValAssign &VA) {
if (VA.isRegLoc()) {
assignValueToReg(VReg, VA);
} else if (VA.isMemLoc()) {
assignValueToAddress(VReg, VA);
} else {
return false;
}
return true;
}
bool MipsCallLowering::MipsHandler::assignVRegs(ArrayRef<unsigned> VRegs,
ArrayRef<CCValAssign> ArgLocs,
unsigned ArgLocsStartIndex) {
for (unsigned i = 0; i < VRegs.size(); ++i)
if (!assign(VRegs[i], ArgLocs[ArgLocsStartIndex + i]))
return false;
return true;
}
void MipsCallLowering::MipsHandler::setLeastSignificantFirst(
SmallVectorImpl<unsigned> &VRegs) {
if (!MIRBuilder.getMF().getDataLayout().isLittleEndian())
std::reverse(VRegs.begin(), VRegs.end());
}
bool MipsCallLowering::MipsHandler::handle(
ArrayRef<CCValAssign> ArgLocs, ArrayRef<CallLowering::ArgInfo> Args) {
SmallVector<unsigned, 4> VRegs;
unsigned SplitLength;
const Function &F = MIRBuilder.getMF().getFunction();
const DataLayout &DL = F.getParent()->getDataLayout();
const MipsTargetLowering &TLI = *static_cast<const MipsTargetLowering *>(
MIRBuilder.getMF().getSubtarget().getTargetLowering());
for (unsigned ArgsIndex = 0, ArgLocsIndex = 0; ArgsIndex < Args.size();
++ArgsIndex, ArgLocsIndex += SplitLength) {
EVT VT = TLI.getValueType(DL, Args[ArgsIndex].Ty);
SplitLength = TLI.getNumRegistersForCallingConv(F.getContext(),
F.getCallingConv(), VT);
if (SplitLength > 1) {
VRegs.clear();
MVT RegisterVT = TLI.getRegisterTypeForCallingConv(
F.getContext(), F.getCallingConv(), VT);
for (unsigned i = 0; i < SplitLength; ++i)
VRegs.push_back(MRI.createGenericVirtualRegister(LLT{RegisterVT}));
if (!handleSplit(VRegs, ArgLocs, ArgLocsIndex, Args[ArgsIndex].Reg))
return false;
} else {
if (!assign(Args[ArgsIndex].Reg, ArgLocs[ArgLocsIndex]))
return false;
}
}
return true;
}
namespace {
class IncomingValueHandler : public MipsCallLowering::MipsHandler {
public:
IncomingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI)
: MipsHandler(MIRBuilder, MRI) {}
private:
void assignValueToReg(unsigned ValVReg, const CCValAssign &VA) override;
unsigned getStackAddress(const CCValAssign &VA,
MachineMemOperand *&MMO) override;
void assignValueToAddress(unsigned ValVReg, const CCValAssign &VA) override;
bool handleSplit(SmallVectorImpl<unsigned> &VRegs,
ArrayRef<CCValAssign> ArgLocs, unsigned ArgLocsStartIndex,
unsigned ArgsReg) override;
virtual void markPhysRegUsed(unsigned PhysReg) {
MIRBuilder.getMBB().addLiveIn(PhysReg);
}
void buildLoad(unsigned Val, const CCValAssign &VA) {
MachineMemOperand *MMO;
unsigned Addr = getStackAddress(VA, MMO);
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,
const CCValAssign &VA) {
unsigned PhysReg = VA.getLocReg();
switch (VA.getLocInfo()) {
case CCValAssign::LocInfo::SExt:
case CCValAssign::LocInfo::ZExt:
case CCValAssign::LocInfo::AExt: {
auto Copy = MIRBuilder.buildCopy(LLT{VA.getLocVT()}, PhysReg);
MIRBuilder.buildTrunc(ValVReg, Copy);
break;
}
default:
MIRBuilder.buildCopy(ValVReg, PhysReg);
break;
}
markPhysRegUsed(PhysReg);
}
unsigned IncomingValueHandler::getStackAddress(const CCValAssign &VA,
MachineMemOperand *&MMO) {
unsigned Size = alignTo(VA.getValVT().getSizeInBits(), 8) / 8;
unsigned Offset = VA.getLocMemOffset();
MachineFrameInfo &MFI = MIRBuilder.getMF().getFrameInfo();
int FI = MFI.CreateFixedObject(Size, Offset, true);
MachinePointerInfo MPO =
MachinePointerInfo::getFixedStack(MIRBuilder.getMF(), FI);
MMO = MIRBuilder.getMF().getMachineMemOperand(MPO, MachineMemOperand::MOLoad,
Size, /* Alignment */ 0);
unsigned AddrReg = MRI.createGenericVirtualRegister(LLT::pointer(0, 32));
MIRBuilder.buildFrameIndex(AddrReg, FI);
return AddrReg;
}
void IncomingValueHandler::assignValueToAddress(unsigned ValVReg,
const CCValAssign &VA) {
if (VA.getLocInfo() == CCValAssign::SExt ||
VA.getLocInfo() == CCValAssign::ZExt ||
VA.getLocInfo() == CCValAssign::AExt) {
unsigned LoadReg = MRI.createGenericVirtualRegister(LLT::scalar(32));
buildLoad(LoadReg, VA);
MIRBuilder.buildTrunc(ValVReg, LoadReg);
} else
buildLoad(ValVReg, VA);
}
bool IncomingValueHandler::handleSplit(SmallVectorImpl<unsigned> &VRegs,
ArrayRef<CCValAssign> ArgLocs,
unsigned ArgLocsStartIndex,
unsigned ArgsReg) {
if (!assignVRegs(VRegs, ArgLocs, ArgLocsStartIndex))
return false;
setLeastSignificantFirst(VRegs);
MIRBuilder.buildMerge(ArgsReg, VRegs);
return true;
}
namespace {
class OutgoingValueHandler : public MipsCallLowering::MipsHandler {
public:
OutgoingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
MachineInstrBuilder &MIB)
: MipsHandler(MIRBuilder, MRI), MIB(MIB) {}
private:
void assignValueToReg(unsigned ValVReg, const CCValAssign &VA) override;
unsigned getStackAddress(const CCValAssign &VA,
MachineMemOperand *&MMO) override;
void assignValueToAddress(unsigned ValVReg, const CCValAssign &VA) override;
bool handleSplit(SmallVectorImpl<unsigned> &VRegs,
ArrayRef<CCValAssign> ArgLocs, unsigned ArgLocsStartIndex,
unsigned ArgsReg) override;
unsigned extendRegister(unsigned ValReg, const CCValAssign &VA);
MachineInstrBuilder &MIB;
};
} // end anonymous namespace
void OutgoingValueHandler::assignValueToReg(unsigned ValVReg,
const CCValAssign &VA) {
unsigned PhysReg = VA.getLocReg();
unsigned ExtReg = extendRegister(ValVReg, VA);
MIRBuilder.buildCopy(PhysReg, ExtReg);
MIB.addUse(PhysReg, RegState::Implicit);
}
unsigned OutgoingValueHandler::getStackAddress(const CCValAssign &VA,
MachineMemOperand *&MMO) {
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);
unsigned Offset = VA.getLocMemOffset();
MIRBuilder.buildConstant(OffsetReg, Offset);
unsigned AddrReg = MRI.createGenericVirtualRegister(p0);
MIRBuilder.buildGEP(AddrReg, SPReg, OffsetReg);
MachinePointerInfo MPO =
MachinePointerInfo::getStack(MIRBuilder.getMF(), Offset);
unsigned Size = alignTo(VA.getValVT().getSizeInBits(), 8) / 8;
MMO = MIRBuilder.getMF().getMachineMemOperand(MPO, MachineMemOperand::MOStore,
Size, /* Alignment */ 0);
return AddrReg;
}
void OutgoingValueHandler::assignValueToAddress(unsigned ValVReg,
const CCValAssign &VA) {
MachineMemOperand *MMO;
unsigned Addr = getStackAddress(VA, MMO);
unsigned ExtReg = extendRegister(ValVReg, VA);
MIRBuilder.buildStore(ExtReg, Addr, *MMO);
}
unsigned OutgoingValueHandler::extendRegister(unsigned ValReg,
const CCValAssign &VA) {
LLT LocTy{VA.getLocVT()};
switch (VA.getLocInfo()) {
case CCValAssign::SExt: {
unsigned ExtReg = MRI.createGenericVirtualRegister(LocTy);
MIRBuilder.buildSExt(ExtReg, ValReg);
return ExtReg;
}
case CCValAssign::ZExt: {
unsigned ExtReg = MRI.createGenericVirtualRegister(LocTy);
MIRBuilder.buildZExt(ExtReg, ValReg);
return ExtReg;
}
case CCValAssign::AExt: {
unsigned ExtReg = MRI.createGenericVirtualRegister(LocTy);
MIRBuilder.buildAnyExt(ExtReg, ValReg);
return ExtReg;
}
// TODO : handle upper extends
case CCValAssign::Full:
return ValReg;
default:
break;
}
llvm_unreachable("unable to extend register");
}
bool OutgoingValueHandler::handleSplit(SmallVectorImpl<unsigned> &VRegs,
ArrayRef<CCValAssign> ArgLocs,
unsigned ArgLocsStartIndex,
unsigned ArgsReg) {
MIRBuilder.buildUnmerge(VRegs, ArgsReg);
setLeastSignificantFirst(VRegs);
if (!assignVRegs(VRegs, ArgLocs, ArgLocsStartIndex))
return false;
return true;
}
static bool isSupportedType(Type *T) {
if (T->isIntegerTy())
return true;
if (T->isPointerTy())
return true;
return false;
}
static CCValAssign::LocInfo determineLocInfo(const MVT RegisterVT, const EVT VT,
const ISD::ArgFlagsTy &Flags) {
// > does not mean loss of information as type RegisterVT can't hold type VT,
// it means that type VT is split into multiple registers of type RegisterVT
if (VT.getSizeInBits() >= RegisterVT.getSizeInBits())
return CCValAssign::LocInfo::Full;
if (Flags.isSExt())
return CCValAssign::LocInfo::SExt;
if (Flags.isZExt())
return CCValAssign::LocInfo::ZExt;
return CCValAssign::LocInfo::AExt;
}
template <typename T>
static void setLocInfo(SmallVectorImpl<CCValAssign> &ArgLocs,
const SmallVectorImpl<T> &Arguments) {
for (unsigned i = 0; i < ArgLocs.size(); ++i) {
const CCValAssign &VA = ArgLocs[i];
CCValAssign::LocInfo LocInfo = determineLocInfo(
Arguments[i].VT, Arguments[i].ArgVT, Arguments[i].Flags);
if (VA.isMemLoc())
ArgLocs[i] =
CCValAssign::getMem(VA.getValNo(), VA.getValVT(),
VA.getLocMemOffset(), VA.getLocVT(), LocInfo);
else
ArgLocs[i] = CCValAssign::getReg(VA.getValNo(), VA.getValVT(),
VA.getLocReg(), VA.getLocVT(), LocInfo);
}
}
bool MipsCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
const Value *Val,
ArrayRef<unsigned> VRegs) const {
MachineInstrBuilder Ret = MIRBuilder.buildInstrNoInsert(Mips::RetRA);
if (Val != nullptr && !isSupportedType(Val->getType()))
return false;
if (!VRegs.empty()) {
MachineFunction &MF = MIRBuilder.getMF();
const Function &F = MF.getFunction();
const DataLayout &DL = MF.getDataLayout();
const MipsTargetLowering &TLI = *getTLI<MipsTargetLowering>();
LLVMContext &Ctx = Val->getType()->getContext();
SmallVector<EVT, 4> SplitEVTs;
ComputeValueVTs(TLI, DL, Val->getType(), SplitEVTs);
assert(VRegs.size() == SplitEVTs.size() &&
"For each split Type there should be exactly one VReg.");
SmallVector<ArgInfo, 8> RetInfos;
SmallVector<unsigned, 8> OrigArgIndices;
for (unsigned i = 0; i < SplitEVTs.size(); ++i) {
ArgInfo CurArgInfo = ArgInfo{VRegs[i], SplitEVTs[i].getTypeForEVT(Ctx)};
setArgFlags(CurArgInfo, AttributeList::ReturnIndex, DL, F);
splitToValueTypes(CurArgInfo, 0, RetInfos, OrigArgIndices);
}
SmallVector<ISD::OutputArg, 8> Outs;
subTargetRegTypeForCallingConv(F, RetInfos, OrigArgIndices, Outs);
SmallVector<CCValAssign, 16> ArgLocs;
MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs,
F.getContext());
CCInfo.AnalyzeReturn(Outs, TLI.CCAssignFnForReturn());
setLocInfo(ArgLocs, Outs);
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(F, ArgInfos, OrigArgIndices, Ins);
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());
setLocInfo(ArgLocs, Ins);
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(F, ArgInfos, OrigArgIndices, Outs);
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);
setLocInfo(ArgLocs, Outs);
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(F, ArgInfos, OrigRetIndices, Ins);
SmallVector<CCValAssign, 8> ArgLocs;
MipsCCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs,
F.getContext());
CCInfo.AnalyzeCallResult(Ins, TLI.CCAssignFnForReturn(), OrigRet.Ty, Call);
setLocInfo(ArgLocs, Ins);
CallReturnHandler Handler(MIRBuilder, MF.getRegInfo(), MIB);
if (!Handler.handle(ArgLocs, ArgInfos))
return false;
}
MIRBuilder.buildInstr(Mips::ADJCALLSTACKUP).addImm(NextStackOffset).addImm(0);
return true;
}
template <typename T>
void MipsCallLowering::subTargetRegTypeForCallingConv(
const Function &F, ArrayRef<ArgInfo> Args,
ArrayRef<unsigned> OrigArgIndices, SmallVectorImpl<T> &ISDArgs) const {
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);
unsigned NumRegs = TLI.getNumRegistersForCallingConv(
F.getContext(), F.getCallingConv(), VT);
for (unsigned i = 0; i < NumRegs; ++i) {
ISD::ArgFlagsTy Flags = Arg.Flags;
if (i == 0)
Flags.setOrigAlign(TLI.getABIAlignmentForCallingConv(Arg.Ty, DL));
else
Flags.setOrigAlign(1);
ISDArgs.emplace_back(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);
}
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