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llvm-project/llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp

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//===-- llvm/lib/Target/AMDGPU/AMDGPUCallLowering.cpp - Call lowering -----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file implements the lowering of LLVM calls to machine code calls for
/// GlobalISel.
///
//===----------------------------------------------------------------------===//
#include "AMDGPUCallLowering.h"
#include "AMDGPU.h"
#include "AMDGPUISelLowering.h"
#include "AMDGPUSubtarget.h"
#include "AMDGPUTargetMachine.h"
#include "SIISelLowering.h"
#include "SIMachineFunctionInfo.h"
#include "SIRegisterInfo.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Support/LowLevelTypeImpl.h"
using namespace llvm;
namespace {
struct OutgoingValueHandler : public CallLowering::ValueHandler {
OutgoingValueHandler(MachineIRBuilder &B, MachineRegisterInfo &MRI,
MachineInstrBuilder MIB, CCAssignFn *AssignFn)
: ValueHandler(B, MRI, AssignFn), MIB(MIB) {}
MachineInstrBuilder MIB;
bool isIncomingArgumentHandler() const override { return false; }
Register getStackAddress(uint64_t Size, int64_t Offset,
MachinePointerInfo &MPO) override {
llvm_unreachable("not implemented");
}
void assignValueToAddress(Register ValVReg, Register Addr, uint64_t Size,
MachinePointerInfo &MPO, CCValAssign &VA) override {
llvm_unreachable("not implemented");
}
void assignValueToReg(Register ValVReg, Register PhysReg,
CCValAssign &VA) override {
Register ExtReg;
if (VA.getLocVT().getSizeInBits() < 32) {
// 16-bit types are reported as legal for 32-bit registers. We need to
// extend and do a 32-bit copy to avoid the verifier complaining about it.
ExtReg = MIRBuilder.buildAnyExt(LLT::scalar(32), ValVReg).getReg(0);
} else
ExtReg = extendRegister(ValVReg, VA);
// If this is a scalar return, insert a readfirstlane just in case the value
// ends up in a VGPR.
// FIXME: Assert this is a shader return.
const SIRegisterInfo *TRI
= static_cast<const SIRegisterInfo *>(MRI.getTargetRegisterInfo());
if (TRI->isSGPRReg(MRI, PhysReg)) {
auto ToSGPR = MIRBuilder.buildIntrinsic(Intrinsic::amdgcn_readfirstlane,
{MRI.getType(ExtReg)}, false)
.addReg(ExtReg);
ExtReg = ToSGPR.getReg(0);
}
MIRBuilder.buildCopy(PhysReg, ExtReg);
MIB.addUse(PhysReg, RegState::Implicit);
}
bool assignArg(unsigned ValNo, MVT ValVT, MVT LocVT,
CCValAssign::LocInfo LocInfo,
const CallLowering::ArgInfo &Info,
ISD::ArgFlagsTy Flags,
CCState &State) override {
return AssignFn(ValNo, ValVT, LocVT, LocInfo, Flags, State);
}
};
struct IncomingArgHandler : public CallLowering::ValueHandler {
uint64_t StackUsed = 0;
IncomingArgHandler(MachineIRBuilder &B, MachineRegisterInfo &MRI,
CCAssignFn *AssignFn)
: ValueHandler(B, MRI, AssignFn) {}
Register getStackAddress(uint64_t Size, int64_t Offset,
MachinePointerInfo &MPO) override {
auto &MFI = MIRBuilder.getMF().getFrameInfo();
int FI = MFI.CreateFixedObject(Size, Offset, true);
MPO = MachinePointerInfo::getFixedStack(MIRBuilder.getMF(), FI);
auto AddrReg = MIRBuilder.buildFrameIndex(
LLT::pointer(AMDGPUAS::PRIVATE_ADDRESS, 32), FI);
StackUsed = std::max(StackUsed, Size + Offset);
return AddrReg.getReg(0);
}
void assignValueToReg(Register ValVReg, Register PhysReg,
CCValAssign &VA) override {
markPhysRegUsed(PhysReg);
if (VA.getLocVT().getSizeInBits() < 32) {
// 16-bit types are reported as legal for 32-bit registers. We need to do
// a 32-bit copy, and truncate to avoid the verifier complaining about it.
auto Copy = MIRBuilder.buildCopy(LLT::scalar(32), PhysReg);
MIRBuilder.buildTrunc(ValVReg, Copy);
return;
}
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;
}
}
void assignValueToAddress(Register ValVReg, Register Addr, uint64_t Size,
MachinePointerInfo &MPO, CCValAssign &VA) override {
MachineFunction &MF = MIRBuilder.getMF();
// FIXME: Get alignment
auto MMO = MF.getMachineMemOperand(
MPO, MachineMemOperand::MOLoad | MachineMemOperand::MOInvariant, Size,
inferAlignFromPtrInfo(MF, MPO));
MIRBuilder.buildLoad(ValVReg, Addr, *MMO);
}
/// How the physical register gets marked varies between formal
/// parameters (it's a basic-block live-in), and a call instruction
/// (it's an implicit-def of the BL).
virtual void markPhysRegUsed(unsigned PhysReg) = 0;
// FIXME: What is the point of this being a callback?
bool isIncomingArgumentHandler() const override { return true; }
};
struct FormalArgHandler : public IncomingArgHandler {
FormalArgHandler(MachineIRBuilder &B, MachineRegisterInfo &MRI,
CCAssignFn *AssignFn)
: IncomingArgHandler(B, MRI, AssignFn) {}
void markPhysRegUsed(unsigned PhysReg) override {
MIRBuilder.getMBB().addLiveIn(PhysReg);
}
};
}
AMDGPUCallLowering::AMDGPUCallLowering(const AMDGPUTargetLowering &TLI)
: CallLowering(&TLI) {
}
// FIXME: Compatability shim
static ISD::NodeType extOpcodeToISDExtOpcode(unsigned MIOpc) {
switch (MIOpc) {
case TargetOpcode::G_SEXT:
return ISD::SIGN_EXTEND;
case TargetOpcode::G_ZEXT:
return ISD::ZERO_EXTEND;
case TargetOpcode::G_ANYEXT:
return ISD::ANY_EXTEND;
default:
llvm_unreachable("not an extend opcode");
}
}
void AMDGPUCallLowering::splitToValueTypes(
MachineIRBuilder &B,
const ArgInfo &OrigArg, unsigned OrigArgIdx,
SmallVectorImpl<ArgInfo> &SplitArgs,
const DataLayout &DL, CallingConv::ID CallConv,
SplitArgTy PerformArgSplit) const {
const SITargetLowering &TLI = *getTLI<SITargetLowering>();
LLVMContext &Ctx = OrigArg.Ty->getContext();
if (OrigArg.Ty->isVoidTy())
return;
SmallVector<EVT, 4> SplitVTs;
ComputeValueVTs(TLI, DL, OrigArg.Ty, SplitVTs);
assert(OrigArg.Regs.size() == SplitVTs.size());
int SplitIdx = 0;
for (EVT VT : SplitVTs) {
Register Reg = OrigArg.Regs[SplitIdx];
Type *Ty = VT.getTypeForEVT(Ctx);
LLT LLTy = getLLTForType(*Ty, DL);
if (OrigArgIdx == AttributeList::ReturnIndex && VT.isScalarInteger()) {
unsigned ExtendOp = TargetOpcode::G_ANYEXT;
if (OrigArg.Flags[0].isSExt()) {
assert(OrigArg.Regs.size() == 1 && "expect only simple return values");
ExtendOp = TargetOpcode::G_SEXT;
} else if (OrigArg.Flags[0].isZExt()) {
assert(OrigArg.Regs.size() == 1 && "expect only simple return values");
ExtendOp = TargetOpcode::G_ZEXT;
}
EVT ExtVT = TLI.getTypeForExtReturn(Ctx, VT,
extOpcodeToISDExtOpcode(ExtendOp));
if (ExtVT != VT) {
VT = ExtVT;
Ty = ExtVT.getTypeForEVT(Ctx);
LLTy = getLLTForType(*Ty, DL);
Reg = B.buildInstr(ExtendOp, {LLTy}, {Reg}).getReg(0);
}
}
unsigned NumParts = TLI.getNumRegistersForCallingConv(Ctx, CallConv, VT);
MVT RegVT = TLI.getRegisterTypeForCallingConv(Ctx, CallConv, VT);
if (NumParts == 1) {
// Fixup EVTs to an MVT.
//
// FIXME: This is pretty hacky. Why do we have to split the type
// legalization logic between here and handleAssignments?
if (OrigArgIdx != AttributeList::ReturnIndex && VT != RegVT) {
assert(VT.getSizeInBits() < 32 &&
"unexpected illegal type");
Ty = Type::getInt32Ty(Ctx);
Register OrigReg = Reg;
Reg = B.getMRI()->createGenericVirtualRegister(LLT::scalar(32));
B.buildTrunc(OrigReg, Reg);
}
// No splitting to do, but we want to replace the original type (e.g. [1 x
// double] -> double).
SplitArgs.emplace_back(Reg, Ty, OrigArg.Flags, OrigArg.IsFixed);
++SplitIdx;
continue;
}
SmallVector<Register, 8> SplitRegs;
Type *PartTy = EVT(RegVT).getTypeForEVT(Ctx);
LLT PartLLT = getLLTForType(*PartTy, DL);
MachineRegisterInfo &MRI = *B.getMRI();
// FIXME: Should we be reporting all of the part registers for a single
// argument, and let handleAssignments take care of the repacking?
for (unsigned i = 0; i < NumParts; ++i) {
Register PartReg = MRI.createGenericVirtualRegister(PartLLT);
SplitRegs.push_back(PartReg);
SplitArgs.emplace_back(ArrayRef<Register>(PartReg), PartTy, OrigArg.Flags);
}
PerformArgSplit(SplitRegs, Reg, LLTy, PartLLT, SplitIdx);
++SplitIdx;
}
}
// Get the appropriate type to make \p OrigTy \p Factor times bigger.
static LLT getMultipleType(LLT OrigTy, int Factor) {
if (OrigTy.isVector()) {
return LLT::vector(OrigTy.getNumElements() * Factor,
OrigTy.getElementType());
}
return LLT::scalar(OrigTy.getSizeInBits() * Factor);
}
// TODO: Move to generic code
static void unpackRegsToOrigType(MachineIRBuilder &B,
ArrayRef<Register> DstRegs,
Register SrcReg,
const CallLowering::ArgInfo &Info,
LLT SrcTy,
LLT PartTy) {
assert(DstRegs.size() > 1 && "Nothing to unpack");
const unsigned SrcSize = SrcTy.getSizeInBits();
const unsigned PartSize = PartTy.getSizeInBits();
if (SrcTy.isVector() && !PartTy.isVector() &&
PartSize > SrcTy.getElementType().getSizeInBits()) {
// Vector was scalarized, and the elements extended.
auto UnmergeToEltTy = B.buildUnmerge(SrcTy.getElementType(),
SrcReg);
for (int i = 0, e = DstRegs.size(); i != e; ++i)
B.buildAnyExt(DstRegs[i], UnmergeToEltTy.getReg(i));
return;
}
if (SrcSize % PartSize == 0) {
B.buildUnmerge(DstRegs, SrcReg);
return;
}
const int NumRoundedParts = (SrcSize + PartSize - 1) / PartSize;
LLT BigTy = getMultipleType(PartTy, NumRoundedParts);
auto ImpDef = B.buildUndef(BigTy);
auto Big = B.buildInsert(BigTy, ImpDef.getReg(0), SrcReg, 0).getReg(0);
int64_t Offset = 0;
for (unsigned i = 0, e = DstRegs.size(); i != e; ++i, Offset += PartSize)
B.buildExtract(DstRegs[i], Big, Offset);
}
/// Lower the return value for the already existing \p Ret. This assumes that
/// \p B's insertion point is correct.
bool AMDGPUCallLowering::lowerReturnVal(MachineIRBuilder &B,
const Value *Val, ArrayRef<Register> VRegs,
MachineInstrBuilder &Ret) const {
if (!Val)
return true;
auto &MF = B.getMF();
const auto &F = MF.getFunction();
const DataLayout &DL = MF.getDataLayout();
MachineRegisterInfo *MRI = B.getMRI();
CallingConv::ID CC = F.getCallingConv();
const SITargetLowering &TLI = *getTLI<SITargetLowering>();
ArgInfo OrigRetInfo(VRegs, Val->getType());
setArgFlags(OrigRetInfo, AttributeList::ReturnIndex, DL, F);
SmallVector<ArgInfo, 4> SplitRetInfos;
splitToValueTypes(
B, OrigRetInfo, AttributeList::ReturnIndex, SplitRetInfos, DL, CC,
[&](ArrayRef<Register> Regs, Register SrcReg, LLT LLTy, LLT PartLLT,
int VTSplitIdx) {
unpackRegsToOrigType(B, Regs, SrcReg,
SplitRetInfos[VTSplitIdx],
LLTy, PartLLT);
});
CCAssignFn *AssignFn = TLI.CCAssignFnForReturn(CC, F.isVarArg());
OutgoingValueHandler RetHandler(B, *MRI, Ret, AssignFn);
return handleAssignments(B, SplitRetInfos, RetHandler);
}
bool AMDGPUCallLowering::lowerReturn(MachineIRBuilder &B,
const Value *Val,
ArrayRef<Register> VRegs) const {
MachineFunction &MF = B.getMF();
MachineRegisterInfo &MRI = MF.getRegInfo();
SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
MFI->setIfReturnsVoid(!Val);
assert(!Val == VRegs.empty() && "Return value without a vreg");
CallingConv::ID CC = B.getMF().getFunction().getCallingConv();
const bool IsShader = AMDGPU::isShader(CC);
const bool IsWaveEnd = (IsShader && MFI->returnsVoid()) ||
AMDGPU::isKernel(CC);
if (IsWaveEnd) {
B.buildInstr(AMDGPU::S_ENDPGM)
.addImm(0);
return true;
}
auto const &ST = MF.getSubtarget<GCNSubtarget>();
unsigned ReturnOpc =
IsShader ? AMDGPU::SI_RETURN_TO_EPILOG : AMDGPU::S_SETPC_B64_return;
auto Ret = B.buildInstrNoInsert(ReturnOpc);
Register ReturnAddrVReg;
if (ReturnOpc == AMDGPU::S_SETPC_B64_return) {
ReturnAddrVReg = MRI.createVirtualRegister(&AMDGPU::CCR_SGPR_64RegClass);
Ret.addUse(ReturnAddrVReg);
}
if (!lowerReturnVal(B, Val, VRegs, Ret))
return false;
if (ReturnOpc == AMDGPU::S_SETPC_B64_return) {
const SIRegisterInfo *TRI = ST.getRegisterInfo();
Register LiveInReturn = MF.addLiveIn(TRI->getReturnAddressReg(MF),
&AMDGPU::SGPR_64RegClass);
B.buildCopy(ReturnAddrVReg, LiveInReturn);
}
// TODO: Handle CalleeSavedRegsViaCopy.
B.insertInstr(Ret);
return true;
}
Register AMDGPUCallLowering::lowerParameterPtr(MachineIRBuilder &B,
Type *ParamTy,
uint64_t Offset) const {
MachineFunction &MF = B.getMF();
const SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
MachineRegisterInfo &MRI = MF.getRegInfo();
const Function &F = MF.getFunction();
const DataLayout &DL = F.getParent()->getDataLayout();
PointerType *PtrTy = PointerType::get(ParamTy, AMDGPUAS::CONSTANT_ADDRESS);
LLT PtrType = getLLTForType(*PtrTy, DL);
Register KernArgSegmentPtr =
MFI->getPreloadedReg(AMDGPUFunctionArgInfo::KERNARG_SEGMENT_PTR);
Register KernArgSegmentVReg = MRI.getLiveInVirtReg(KernArgSegmentPtr);
auto OffsetReg = B.buildConstant(LLT::scalar(64), Offset);
return B.buildPtrAdd(PtrType, KernArgSegmentVReg, OffsetReg).getReg(0);
}
void AMDGPUCallLowering::lowerParameter(MachineIRBuilder &B, Type *ParamTy,
uint64_t Offset, Align Alignment,
Register DstReg) const {
MachineFunction &MF = B.getMF();
const Function &F = MF.getFunction();
const DataLayout &DL = F.getParent()->getDataLayout();
MachinePointerInfo PtrInfo(AMDGPUAS::CONSTANT_ADDRESS);
unsigned TypeSize = DL.getTypeStoreSize(ParamTy);
Register PtrReg = lowerParameterPtr(B, ParamTy, Offset);
MachineMemOperand *MMO = MF.getMachineMemOperand(
PtrInfo,
MachineMemOperand::MOLoad | MachineMemOperand::MODereferenceable |
MachineMemOperand::MOInvariant,
TypeSize, Alignment);
B.buildLoad(DstReg, PtrReg, *MMO);
}
// Allocate special inputs passed in user SGPRs.
static void allocateHSAUserSGPRs(CCState &CCInfo,
MachineIRBuilder &B,
MachineFunction &MF,
const SIRegisterInfo &TRI,
SIMachineFunctionInfo &Info) {
// FIXME: How should these inputs interact with inreg / custom SGPR inputs?
if (Info.hasPrivateSegmentBuffer()) {
Register PrivateSegmentBufferReg = Info.addPrivateSegmentBuffer(TRI);
MF.addLiveIn(PrivateSegmentBufferReg, &AMDGPU::SGPR_128RegClass);
CCInfo.AllocateReg(PrivateSegmentBufferReg);
}
if (Info.hasDispatchPtr()) {
Register DispatchPtrReg = Info.addDispatchPtr(TRI);
MF.addLiveIn(DispatchPtrReg, &AMDGPU::SGPR_64RegClass);
CCInfo.AllocateReg(DispatchPtrReg);
}
if (Info.hasQueuePtr()) {
Register QueuePtrReg = Info.addQueuePtr(TRI);
MF.addLiveIn(QueuePtrReg, &AMDGPU::SGPR_64RegClass);
CCInfo.AllocateReg(QueuePtrReg);
}
if (Info.hasKernargSegmentPtr()) {
MachineRegisterInfo &MRI = MF.getRegInfo();
Register InputPtrReg = Info.addKernargSegmentPtr(TRI);
const LLT P4 = LLT::pointer(AMDGPUAS::CONSTANT_ADDRESS, 64);
Register VReg = MRI.createGenericVirtualRegister(P4);
MRI.addLiveIn(InputPtrReg, VReg);
B.getMBB().addLiveIn(InputPtrReg);
B.buildCopy(VReg, InputPtrReg);
CCInfo.AllocateReg(InputPtrReg);
}
if (Info.hasDispatchID()) {
Register DispatchIDReg = Info.addDispatchID(TRI);
MF.addLiveIn(DispatchIDReg, &AMDGPU::SGPR_64RegClass);
CCInfo.AllocateReg(DispatchIDReg);
}
if (Info.hasFlatScratchInit()) {
Register FlatScratchInitReg = Info.addFlatScratchInit(TRI);
MF.addLiveIn(FlatScratchInitReg, &AMDGPU::SGPR_64RegClass);
CCInfo.AllocateReg(FlatScratchInitReg);
}
// TODO: Add GridWorkGroupCount user SGPRs when used. For now with HSA we read
// these from the dispatch pointer.
}
bool AMDGPUCallLowering::lowerFormalArgumentsKernel(
MachineIRBuilder &B, const Function &F,
ArrayRef<ArrayRef<Register>> VRegs) const {
MachineFunction &MF = B.getMF();
const GCNSubtarget *Subtarget = &MF.getSubtarget<GCNSubtarget>();
MachineRegisterInfo &MRI = MF.getRegInfo();
SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
const SIRegisterInfo *TRI = Subtarget->getRegisterInfo();
const SITargetLowering &TLI = *getTLI<SITargetLowering>();
const DataLayout &DL = F.getParent()->getDataLayout();
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(F.getCallingConv(), F.isVarArg(), MF, ArgLocs, F.getContext());
allocateHSAUserSGPRs(CCInfo, B, MF, *TRI, *Info);
unsigned i = 0;
const Align KernArgBaseAlign(16);
const unsigned BaseOffset = Subtarget->getExplicitKernelArgOffset(F);
uint64_t ExplicitArgOffset = 0;
// TODO: Align down to dword alignment and extract bits for extending loads.
for (auto &Arg : F.args()) {
Type *ArgTy = Arg.getType();
unsigned AllocSize = DL.getTypeAllocSize(ArgTy);
if (AllocSize == 0)
continue;
Align ABIAlign = DL.getABITypeAlign(ArgTy);
uint64_t ArgOffset = alignTo(ExplicitArgOffset, ABIAlign) + BaseOffset;
ExplicitArgOffset = alignTo(ExplicitArgOffset, ABIAlign) + AllocSize;
ArrayRef<Register> OrigArgRegs = VRegs[i];
Register ArgReg =
OrigArgRegs.size() == 1
? OrigArgRegs[0]
: MRI.createGenericVirtualRegister(getLLTForType(*ArgTy, DL));
Align Alignment = commonAlignment(KernArgBaseAlign, ArgOffset);
lowerParameter(B, ArgTy, ArgOffset, Alignment, ArgReg);
if (OrigArgRegs.size() > 1)
unpackRegs(OrigArgRegs, ArgReg, ArgTy, B);
++i;
}
TLI.allocateSpecialEntryInputVGPRs(CCInfo, MF, *TRI, *Info);
TLI.allocateSystemSGPRs(CCInfo, MF, *Info, F.getCallingConv(), false);
return true;
}
/// Pack values \p SrcRegs to cover the vector type result \p DstRegs.
static MachineInstrBuilder mergeVectorRegsToResultRegs(
MachineIRBuilder &B, ArrayRef<Register> DstRegs, ArrayRef<Register> SrcRegs) {
MachineRegisterInfo &MRI = *B.getMRI();
LLT LLTy = MRI.getType(DstRegs[0]);
LLT PartLLT = MRI.getType(SrcRegs[0]);
// Deal with v3s16 split into v2s16
LLT LCMTy = getLCMType(LLTy, PartLLT);
if (LCMTy == LLTy) {
// Common case where no padding is needed.
assert(DstRegs.size() == 1);
return B.buildConcatVectors(DstRegs[0], SrcRegs);
}
const int NumWide = LCMTy.getSizeInBits() / PartLLT.getSizeInBits();
Register Undef = B.buildUndef(PartLLT).getReg(0);
// Build vector of undefs.
SmallVector<Register, 8> WidenedSrcs(NumWide, Undef);
// Replace the first sources with the real registers.
std::copy(SrcRegs.begin(), SrcRegs.end(), WidenedSrcs.begin());
auto Widened = B.buildConcatVectors(LCMTy, WidenedSrcs);
int NumDst = LCMTy.getSizeInBits() / LLTy.getSizeInBits();
SmallVector<Register, 8> PadDstRegs(NumDst);
std::copy(DstRegs.begin(), DstRegs.end(), PadDstRegs.begin());
// Create the excess dead defs for the unmerge.
for (int I = DstRegs.size(); I != NumDst; ++I)
PadDstRegs[I] = MRI.createGenericVirtualRegister(LLTy);
return B.buildUnmerge(PadDstRegs, Widened);
}
// TODO: Move this to generic code
static void packSplitRegsToOrigType(MachineIRBuilder &B,
ArrayRef<Register> OrigRegs,
ArrayRef<Register> Regs,
LLT LLTy,
LLT PartLLT) {
MachineRegisterInfo &MRI = *B.getMRI();
if (!LLTy.isVector() && !PartLLT.isVector()) {
assert(OrigRegs.size() == 1);
LLT OrigTy = MRI.getType(OrigRegs[0]);
unsigned SrcSize = PartLLT.getSizeInBits() * Regs.size();
if (SrcSize == OrigTy.getSizeInBits())
B.buildMerge(OrigRegs[0], Regs);
else {
auto Widened = B.buildMerge(LLT::scalar(SrcSize), Regs);
B.buildTrunc(OrigRegs[0], Widened);
}
return;
}
if (LLTy.isVector() && PartLLT.isVector()) {
assert(OrigRegs.size() == 1);
assert(LLTy.getElementType() == PartLLT.getElementType());
mergeVectorRegsToResultRegs(B, OrigRegs, Regs);
return;
}
assert(LLTy.isVector() && !PartLLT.isVector());
LLT DstEltTy = LLTy.getElementType();
// Pointer information was discarded. We'll need to coerce some register types
// to avoid violating type constraints.
LLT RealDstEltTy = MRI.getType(OrigRegs[0]).getElementType();
assert(DstEltTy.getSizeInBits() == RealDstEltTy.getSizeInBits());
if (DstEltTy == PartLLT) {
// Vector was trivially scalarized.
if (RealDstEltTy.isPointer()) {
for (Register Reg : Regs)
MRI.setType(Reg, RealDstEltTy);
}
B.buildBuildVector(OrigRegs[0], Regs);
} else if (DstEltTy.getSizeInBits() > PartLLT.getSizeInBits()) {
// Deal with vector with 64-bit elements decomposed to 32-bit
// registers. Need to create intermediate 64-bit elements.
SmallVector<Register, 8> EltMerges;
int PartsPerElt = DstEltTy.getSizeInBits() / PartLLT.getSizeInBits();
assert(DstEltTy.getSizeInBits() % PartLLT.getSizeInBits() == 0);
for (int I = 0, NumElts = LLTy.getNumElements(); I != NumElts; ++I) {
auto Merge = B.buildMerge(RealDstEltTy, Regs.take_front(PartsPerElt));
// Fix the type in case this is really a vector of pointers.
MRI.setType(Merge.getReg(0), RealDstEltTy);
EltMerges.push_back(Merge.getReg(0));
Regs = Regs.drop_front(PartsPerElt);
}
B.buildBuildVector(OrigRegs[0], EltMerges);
} else {
// Vector was split, and elements promoted to a wider type.
LLT BVType = LLT::vector(LLTy.getNumElements(), PartLLT);
auto BV = B.buildBuildVector(BVType, Regs);
B.buildTrunc(OrigRegs[0], BV);
}
}
bool AMDGPUCallLowering::lowerFormalArguments(
MachineIRBuilder &B, const Function &F,
ArrayRef<ArrayRef<Register>> VRegs) const {
CallingConv::ID CC = F.getCallingConv();
// The infrastructure for normal calling convention lowering is essentially
// useless for kernels. We want to avoid any kind of legalization or argument
// splitting.
if (CC == CallingConv::AMDGPU_KERNEL)
return lowerFormalArgumentsKernel(B, F, VRegs);
const bool IsShader = AMDGPU::isShader(CC);
const bool IsEntryFunc = AMDGPU::isEntryFunctionCC(CC);
MachineFunction &MF = B.getMF();
MachineBasicBlock &MBB = B.getMBB();
MachineRegisterInfo &MRI = MF.getRegInfo();
SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
const GCNSubtarget &Subtarget = MF.getSubtarget<GCNSubtarget>();
const SIRegisterInfo *TRI = Subtarget.getRegisterInfo();
const DataLayout &DL = F.getParent()->getDataLayout();
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, F.isVarArg(), MF, ArgLocs, F.getContext());
if (!IsEntryFunc) {
Register ReturnAddrReg = TRI->getReturnAddressReg(MF);
Register LiveInReturn = MF.addLiveIn(ReturnAddrReg,
&AMDGPU::SGPR_64RegClass);
MBB.addLiveIn(ReturnAddrReg);
B.buildCopy(LiveInReturn, ReturnAddrReg);
}
if (Info->hasImplicitBufferPtr()) {
Register ImplicitBufferPtrReg = Info->addImplicitBufferPtr(*TRI);
MF.addLiveIn(ImplicitBufferPtrReg, &AMDGPU::SGPR_64RegClass);
CCInfo.AllocateReg(ImplicitBufferPtrReg);
}
SmallVector<ArgInfo, 32> SplitArgs;
unsigned Idx = 0;
unsigned PSInputNum = 0;
for (auto &Arg : F.args()) {
if (DL.getTypeStoreSize(Arg.getType()) == 0)
continue;
const bool InReg = Arg.hasAttribute(Attribute::InReg);
// SGPR arguments to functions not implemented.
if (!IsShader && InReg)
return false;
if (Arg.hasAttribute(Attribute::SwiftSelf) ||
Arg.hasAttribute(Attribute::SwiftError) ||
Arg.hasAttribute(Attribute::Nest))
return false;
if (CC == CallingConv::AMDGPU_PS && !InReg && PSInputNum <= 15) {
const bool ArgUsed = !Arg.use_empty();
bool SkipArg = !ArgUsed && !Info->isPSInputAllocated(PSInputNum);
if (!SkipArg) {
Info->markPSInputAllocated(PSInputNum);
if (ArgUsed)
Info->markPSInputEnabled(PSInputNum);
}
++PSInputNum;
if (SkipArg) {
for (int I = 0, E = VRegs[Idx].size(); I != E; ++I)
B.buildUndef(VRegs[Idx][I]);
++Idx;
continue;
}
}
ArgInfo OrigArg(VRegs[Idx], Arg.getType());
const unsigned OrigArgIdx = Idx + AttributeList::FirstArgIndex;
setArgFlags(OrigArg, OrigArgIdx, DL, F);
splitToValueTypes(
B, OrigArg, OrigArgIdx, SplitArgs, DL, CC,
// FIXME: We should probably be passing multiple registers to
// handleAssignments to do this
[&](ArrayRef<Register> Regs, Register DstReg,
LLT LLTy, LLT PartLLT, int VTSplitIdx) {
assert(DstReg == VRegs[Idx][VTSplitIdx]);
packSplitRegsToOrigType(B, VRegs[Idx][VTSplitIdx], Regs,
LLTy, PartLLT);
});
++Idx;
}
// At least one interpolation mode must be enabled or else the GPU will
// hang.
//
// Check PSInputAddr instead of PSInputEnable. The idea is that if the user
// set PSInputAddr, the user wants to enable some bits after the compilation
// based on run-time states. Since we can't know what the final PSInputEna
// will look like, so we shouldn't do anything here and the user should take
// responsibility for the correct programming.
//
// Otherwise, the following restrictions apply:
// - At least one of PERSP_* (0xF) or LINEAR_* (0x70) must be enabled.
// - If POS_W_FLOAT (11) is enabled, at least one of PERSP_* must be
// enabled too.
if (CC == CallingConv::AMDGPU_PS) {
if ((Info->getPSInputAddr() & 0x7F) == 0 ||
((Info->getPSInputAddr() & 0xF) == 0 &&
Info->isPSInputAllocated(11))) {
CCInfo.AllocateReg(AMDGPU::VGPR0);
CCInfo.AllocateReg(AMDGPU::VGPR1);
Info->markPSInputAllocated(0);
Info->markPSInputEnabled(0);
}
if (Subtarget.isAmdPalOS()) {
// For isAmdPalOS, the user does not enable some bits after compilation
// based on run-time states; the register values being generated here are
// the final ones set in hardware. Therefore we need to apply the
// workaround to PSInputAddr and PSInputEnable together. (The case where
// a bit is set in PSInputAddr but not PSInputEnable is where the frontend
// set up an input arg for a particular interpolation mode, but nothing
// uses that input arg. Really we should have an earlier pass that removes
// such an arg.)
unsigned PsInputBits = Info->getPSInputAddr() & Info->getPSInputEnable();
if ((PsInputBits & 0x7F) == 0 ||
((PsInputBits & 0xF) == 0 &&
(PsInputBits >> 11 & 1)))
Info->markPSInputEnabled(
countTrailingZeros(Info->getPSInputAddr(), ZB_Undefined));
}
}
const SITargetLowering &TLI = *getTLI<SITargetLowering>();
CCAssignFn *AssignFn = TLI.CCAssignFnForCall(CC, F.isVarArg());
if (!MBB.empty())
B.setInstr(*MBB.begin());
if (!IsEntryFunc) {
// For the fixed ABI, pass workitem IDs in the last argument register.
if (AMDGPUTargetMachine::EnableFixedFunctionABI)
TLI.allocateSpecialInputVGPRsFixed(CCInfo, MF, *TRI, *Info);
}
FormalArgHandler Handler(B, MRI, AssignFn);
if (!handleAssignments(CCInfo, ArgLocs, B, SplitArgs, Handler))
return false;
if (!IsEntryFunc && !AMDGPUTargetMachine::EnableFixedFunctionABI) {
// Special inputs come after user arguments.
TLI.allocateSpecialInputVGPRs(CCInfo, MF, *TRI, *Info);
}
// Start adding system SGPRs.
if (IsEntryFunc) {
TLI.allocateSystemSGPRs(CCInfo, MF, *Info, CC, IsShader);
} else {
CCInfo.AllocateReg(Info->getScratchRSrcReg());
TLI.allocateSpecialInputSGPRs(CCInfo, MF, *TRI, *Info);
}
// Move back to the end of the basic block.
B.setMBB(MBB);
return true;
}
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