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llvm / llvm-project / 9e8a71caf02a503006eb08b5cd291adeaa20a9c2 / . / llvm / lib / Target / ARC / ARCISelLowering.cpp
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//===- ARCISelLowering.cpp - ARC DAG Lowering Impl --------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the ARCTargetLowering class.
//
//===----------------------------------------------------------------------===//
#include "ARCISelLowering.h"
#include "ARC.h"
#include "ARCMachineFunctionInfo.h"
#include "ARCSubtarget.h"
#include "ARCTargetMachine.h"
#include "MCTargetDesc/ARCInfo.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
#define DEBUG_TYPE "arc-lower"
using namespace llvm;
static SDValue lowerCallResult(SDValue Chain, SDValue InFlag,
const SmallVectorImpl<CCValAssign> &RVLocs,
SDLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals);
static ARCCC::CondCode ISDCCtoARCCC(ISD::CondCode isdCC) {
switch (isdCC) {
case ISD::SETUEQ:
return ARCCC::EQ;
case ISD::SETUGT:
return ARCCC::HI;
case ISD::SETUGE:
return ARCCC::HS;
case ISD::SETULT:
return ARCCC::LO;
case ISD::SETULE:
return ARCCC::LS;
case ISD::SETUNE:
return ARCCC::NE;
case ISD::SETEQ:
return ARCCC::EQ;
case ISD::SETGT:
return ARCCC::GT;
case ISD::SETGE:
return ARCCC::GE;
case ISD::SETLT:
return ARCCC::LT;
case ISD::SETLE:
return ARCCC::LE;
case ISD::SETNE:
return ARCCC::NE;
default:
llvm_unreachable("Unhandled ISDCC code.");
}
}
void ARCTargetLowering::ReplaceNodeResults(SDNode *N,
SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG) const {
LLVM_DEBUG(dbgs() << "[ARC-ISEL] ReplaceNodeResults ");
LLVM_DEBUG(N->dump(&DAG));
LLVM_DEBUG(dbgs() << "; use_count=" << N->use_size() << "\n");
switch (N->getOpcode()) {
case ISD::READCYCLECOUNTER:
if (N->getValueType(0) == MVT::i64) {
// We read the TIMER0 and zero-extend it to 64-bits as the intrinsic
// requires.
SDValue V =
DAG.getNode(ISD::READCYCLECOUNTER, SDLoc(N),
DAG.getVTList(MVT::i32, MVT::Other), N->getOperand(0));
SDValue Op = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), MVT::i64, V);
Results.push_back(Op);
Results.push_back(V.getValue(1));
}
break;
default:
break;
}
}
ARCTargetLowering::ARCTargetLowering(const TargetMachine &TM,
const ARCSubtarget &Subtarget)
: TargetLowering(TM), Subtarget(Subtarget) {
// Set up the register classes.
addRegisterClass(MVT::i32, &ARC::GPR32RegClass);
// Compute derived properties from the register classes
computeRegisterProperties(Subtarget.getRegisterInfo());
setStackPointerRegisterToSaveRestore(ARC::SP);
setSchedulingPreference(Sched::Source);
// Use i32 for setcc operations results (slt, sgt, ...).
setBooleanContents(ZeroOrOneBooleanContent);
setBooleanVectorContents(ZeroOrOneBooleanContent);
for (unsigned Opc = 0; Opc < ISD::BUILTIN_OP_END; ++Opc)
setOperationAction(Opc, MVT::i32, Expand);
// Operations to get us off of the ground.
// Basic.
setOperationAction(ISD::ADD, MVT::i32, Legal);
setOperationAction(ISD::SUB, MVT::i32, Legal);
setOperationAction(ISD::AND, MVT::i32, Legal);
setOperationAction(ISD::SMAX, MVT::i32, Legal);
setOperationAction(ISD::SMIN, MVT::i32, Legal);
setOperationAction(ISD::ADDC, MVT::i32, Legal);
setOperationAction(ISD::ADDE, MVT::i32, Legal);
setOperationAction(ISD::SUBC, MVT::i32, Legal);
setOperationAction(ISD::SUBE, MVT::i32, Legal);
// Need barrel shifter.
setOperationAction(ISD::SHL, MVT::i32, Legal);
setOperationAction(ISD::SRA, MVT::i32, Legal);
setOperationAction(ISD::SRL, MVT::i32, Legal);
setOperationAction(ISD::ROTR, MVT::i32, Legal);
setOperationAction(ISD::Constant, MVT::i32, Legal);
setOperationAction(ISD::UNDEF, MVT::i32, Legal);
// Need multiplier
setOperationAction(ISD::MUL, MVT::i32, Legal);
setOperationAction(ISD::MULHS, MVT::i32, Legal);
setOperationAction(ISD::MULHU, MVT::i32, Legal);
setOperationAction(ISD::LOAD, MVT::i32, Legal);
setOperationAction(ISD::STORE, MVT::i32, Legal);
setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
setOperationAction(ISD::BR_CC, MVT::i32, Custom);
setOperationAction(ISD::BRCOND, MVT::Other, Expand);
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::JumpTable, MVT::i32, Custom);
// Have pseudo instruction for frame addresses.
setOperationAction(ISD::FRAMEADDR, MVT::i32, Legal);
// Custom lower global addresses.
setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
// Expand var-args ops.
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::VAEND, MVT::Other, Expand);
setOperationAction(ISD::VAARG, MVT::Other, Expand);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
// Other expansions
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
// Sign extend inreg
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Custom);
// TODO: Predicate these with `options.hasBitScan() ? Legal : Expand`
// when the HasBitScan predicate is available.
setOperationAction(ISD::CTLZ, MVT::i32, Legal);
setOperationAction(ISD::CTTZ, MVT::i32, Legal);
setOperationAction(ISD::READCYCLECOUNTER, MVT::i32, Legal);
setOperationAction(ISD::READCYCLECOUNTER, MVT::i64,
isTypeLegal(MVT::i64) ? Legal : Custom);
}
const char *ARCTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
case ARCISD::BL:
return "ARCISD::BL";
case ARCISD::CMOV:
return "ARCISD::CMOV";
case ARCISD::CMP:
return "ARCISD::CMP";
case ARCISD::BRcc:
return "ARCISD::BRcc";
case ARCISD::RET:
return "ARCISD::RET";
case ARCISD::GAWRAPPER:
return "ARCISD::GAWRAPPER";
}
return nullptr;
}
//===----------------------------------------------------------------------===//
// Misc Lower Operation implementation
//===----------------------------------------------------------------------===//
SDValue ARCTargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
SDValue TVal = Op.getOperand(2);
SDValue FVal = Op.getOperand(3);
SDLoc dl(Op);
ARCCC::CondCode ArcCC = ISDCCtoARCCC(CC);
assert(LHS.getValueType() == MVT::i32 && "Only know how to SELECT_CC i32");
SDValue Cmp = DAG.getNode(ARCISD::CMP, dl, MVT::Glue, LHS, RHS);
return DAG.getNode(ARCISD::CMOV, dl, TVal.getValueType(), TVal, FVal,
DAG.getConstant(ArcCC, dl, MVT::i32), Cmp);
}
SDValue ARCTargetLowering::LowerSIGN_EXTEND_INREG(SDValue Op,
SelectionDAG &DAG) const {
SDValue Op0 = Op.getOperand(0);
SDLoc dl(Op);
assert(Op.getValueType() == MVT::i32 &&
"Unhandled target sign_extend_inreg.");
// These are legal
unsigned Width = cast<VTSDNode>(Op.getOperand(1))->getVT().getSizeInBits();
if (Width == 16 || Width == 8)
return Op;
if (Width >= 32) {
return {};
}
SDValue LS = DAG.getNode(ISD::SHL, dl, MVT::i32, Op0,
DAG.getConstant(32 - Width, dl, MVT::i32));
SDValue SR = DAG.getNode(ISD::SRA, dl, MVT::i32, LS,
DAG.getConstant(32 - Width, dl, MVT::i32));
return SR;
}
SDValue ARCTargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
SDValue LHS = Op.getOperand(2);
SDValue RHS = Op.getOperand(3);
SDValue Dest = Op.getOperand(4);
SDLoc dl(Op);
ARCCC::CondCode arcCC = ISDCCtoARCCC(CC);
assert(LHS.getValueType() == MVT::i32 && "Only know how to BR_CC i32");
return DAG.getNode(ARCISD::BRcc, dl, MVT::Other, Chain, Dest, LHS, RHS,
DAG.getConstant(arcCC, dl, MVT::i32));
}
SDValue ARCTargetLowering::LowerJumpTable(SDValue Op, SelectionDAG &DAG) const {
auto *N = cast<JumpTableSDNode>(Op);
SDValue GA = DAG.getTargetJumpTable(N->getIndex(), MVT::i32);
return DAG.getNode(ARCISD::GAWRAPPER, SDLoc(N), MVT::i32, GA);
}
#include "ARCGenCallingConv.inc"
//===----------------------------------------------------------------------===//
// Call Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// ARC call implementation
SDValue ARCTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
SmallVectorImpl<SDValue> &InVals) const {
SelectionDAG &DAG = CLI.DAG;
SDLoc &dl = CLI.DL;
SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
SmallVectorImpl<SDValue> &OutVals = CLI.OutVals;
SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins;
SDValue Chain = CLI.Chain;
SDValue Callee = CLI.Callee;
CallingConv::ID CallConv = CLI.CallConv;
bool IsVarArg = CLI.IsVarArg;
bool &IsTailCall = CLI.IsTailCall;
IsTailCall = false; // Do not support tail calls yet.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
CCInfo.AnalyzeCallOperands(Outs, CC_ARC);
SmallVector<CCValAssign, 16> RVLocs;
// Analyze return values to determine the number of bytes of stack required.
CCState RetCCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), RVLocs,
*DAG.getContext());
RetCCInfo.AllocateStack(CCInfo.getNextStackOffset(), Align(4));
RetCCInfo.AnalyzeCallResult(Ins, RetCC_ARC);
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = RetCCInfo.getNextStackOffset();
auto PtrVT = getPointerTy(DAG.getDataLayout());
Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, dl);
SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
SmallVector<SDValue, 12> MemOpChains;
SDValue StackPtr;
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
SDValue Arg = OutVals[i];
// Promote the value if needed.
switch (VA.getLocInfo()) {
default:
llvm_unreachable("Unknown loc info!");
case CCValAssign::Full:
break;
case CCValAssign::SExt:
Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
break;
}
// Arguments that can be passed on register must be kept at
// RegsToPass vector
if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else {
assert(VA.isMemLoc() && "Must be register or memory argument.");
if (!StackPtr.getNode())
StackPtr = DAG.getCopyFromReg(Chain, dl, ARC::SP,
getPointerTy(DAG.getDataLayout()));
// Calculate the stack position.
SDValue SOffset = DAG.getIntPtrConstant(VA.getLocMemOffset(), dl);
SDValue PtrOff = DAG.getNode(
ISD::ADD, dl, getPointerTy(DAG.getDataLayout()), StackPtr, SOffset);
SDValue Store =
DAG.getStore(Chain, dl, Arg, PtrOff, MachinePointerInfo());
MemOpChains.push_back(Store);
IsTailCall = false;
}
}
// Transform all store nodes into one single node because
// all store nodes are independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
// Build a sequence of copy-to-reg nodes chained together with token
// chain and flag operands which copy the outgoing args into registers.
// The InFlag in necessary since all emitted instructions must be
// stuck together.
SDValue Glue;
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
RegsToPass[i].second, Glue);
Glue = Chain.getValue(1);
}
// If the callee is a GlobalAddress node (quite common, every direct call is)
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
// Likewise ExternalSymbol -> TargetExternalSymbol.
bool IsDirect = true;
if (auto *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl, MVT::i32);
else if (auto *E = dyn_cast<ExternalSymbolSDNode>(Callee))
Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i32);
else
IsDirect = false;
// Branch + Link = #chain, #target_address, #opt_in_flags...
// = Chain, Callee, Reg#1, Reg#2, ...
//
// Returns a chain & a flag for retval copy to use.
SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
SmallVector<SDValue, 8> Ops;
Ops.push_back(Chain);
Ops.push_back(Callee);
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
Ops.push_back(DAG.getRegister(RegsToPass[i].first,
RegsToPass[i].second.getValueType()));
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
const uint32_t *Mask =
TRI->getCallPreservedMask(DAG.getMachineFunction(), CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
if (Glue.getNode())
Ops.push_back(Glue);
Chain = DAG.getNode(IsDirect ? ARCISD::BL : ARCISD::JL, dl, NodeTys, Ops);
Glue = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(Chain, DAG.getConstant(NumBytes, dl, PtrVT, true),
DAG.getConstant(0, dl, PtrVT, true), Glue, dl);
Glue = Chain.getValue(1);
// Handle result values, copying them out of physregs into vregs that we
// return.
if (IsTailCall)
return Chain;
return lowerCallResult(Chain, Glue, RVLocs, dl, DAG, InVals);
}
/// Lower the result values of a call into the appropriate copies out of
/// physical registers / memory locations.
static SDValue lowerCallResult(SDValue Chain, SDValue Glue,
const SmallVectorImpl<CCValAssign> &RVLocs,
SDLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) {
SmallVector<std::pair<int, unsigned>, 4> ResultMemLocs;
// Copy results out of physical registers.
for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
const CCValAssign &VA = RVLocs[i];
if (VA.isRegLoc()) {
SDValue RetValue;
RetValue =
DAG.getCopyFromReg(Chain, dl, VA.getLocReg(), VA.getValVT(), Glue);
Chain = RetValue.getValue(1);
Glue = RetValue.getValue(2);
InVals.push_back(RetValue);
} else {
assert(VA.isMemLoc() && "Must be memory location.");
ResultMemLocs.push_back(
std::make_pair(VA.getLocMemOffset(), InVals.size()));
// Reserve space for this result.
InVals.push_back(SDValue());
}
}
// Copy results out of memory.
SmallVector<SDValue, 4> MemOpChains;
for (unsigned i = 0, e = ResultMemLocs.size(); i != e; ++i) {
int Offset = ResultMemLocs[i].first;
unsigned Index = ResultMemLocs[i].second;
SDValue StackPtr = DAG.getRegister(ARC::SP, MVT::i32);
SDValue SpLoc = DAG.getNode(ISD::ADD, dl, MVT::i32, StackPtr,
DAG.getConstant(Offset, dl, MVT::i32));
SDValue Load =
DAG.getLoad(MVT::i32, dl, Chain, SpLoc, MachinePointerInfo());
InVals[Index] = Load;
MemOpChains.push_back(Load.getValue(1));
}
// Transform all loads nodes into one single node because
// all load nodes are independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
return Chain;
}
//===----------------------------------------------------------------------===//
// Formal Arguments Calling Convention Implementation
//===----------------------------------------------------------------------===//
namespace {
struct ArgDataPair {
SDValue SDV;
ISD::ArgFlagsTy Flags;
};
} // end anonymous namespace
/// ARC formal arguments implementation
SDValue ARCTargetLowering::LowerFormalArguments(
SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
switch (CallConv) {
default:
llvm_unreachable("Unsupported calling convention");
case CallingConv::C:
case CallingConv::Fast:
return LowerCallArguments(Chain, CallConv, IsVarArg, Ins, dl, DAG, InVals);
}
}
/// Transform physical registers into virtual registers, and generate load
/// operations for argument places on the stack.
SDValue ARCTargetLowering::LowerCallArguments(
SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, SDLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo &MFI = MF.getFrameInfo();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
auto *AFI = MF.getInfo<ARCFunctionInfo>();
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
CCInfo.AnalyzeFormalArguments(Ins, CC_ARC);
unsigned StackSlotSize = 4;
if (!IsVarArg)
AFI->setReturnStackOffset(CCInfo.getNextStackOffset());
// All getCopyFromReg ops must precede any getMemcpys to prevent the
// scheduler clobbering a register before it has been copied.
// The stages are:
// 1. CopyFromReg (and load) arg & vararg registers.
// 2. Chain CopyFromReg nodes into a TokenFactor.
// 3. Memcpy 'byVal' args & push final InVals.
// 4. Chain mem ops nodes into a TokenFactor.
SmallVector<SDValue, 4> CFRegNode;
SmallVector<ArgDataPair, 4> ArgData;
SmallVector<SDValue, 4> MemOps;
// 1a. CopyFromReg (and load) arg registers.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
SDValue ArgIn;
if (VA.isRegLoc()) {
// Arguments passed in registers
EVT RegVT = VA.getLocVT();
switch (RegVT.getSimpleVT().SimpleTy) {
default: {
LLVM_DEBUG(errs() << "LowerFormalArguments Unhandled argument type: "
<< (unsigned)RegVT.getSimpleVT().SimpleTy << "\n");
llvm_unreachable("Unhandled LowerFormalArguments type.");
}
case MVT::i32:
unsigned VReg = RegInfo.createVirtualRegister(&ARC::GPR32RegClass);
RegInfo.addLiveIn(VA.getLocReg(), VReg);
ArgIn = DAG.getCopyFromReg(Chain, dl, VReg, RegVT);
CFRegNode.push_back(ArgIn.getValue(ArgIn->getNumValues() - 1));
}
} else {
// Only arguments passed on the stack should make it here.
assert(VA.isMemLoc());
// Load the argument to a virtual register
unsigned ObjSize = VA.getLocVT().getStoreSize();
assert((ObjSize <= StackSlotSize) && "Unhandled argument");
// Create the frame index object for this incoming parameter...
int FI = MFI.CreateFixedObject(ObjSize, VA.getLocMemOffset(), true);
// Create the SelectionDAG nodes corresponding to a load
// from this parameter
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
ArgIn = DAG.getLoad(VA.getLocVT(), dl, Chain, FIN,
MachinePointerInfo::getFixedStack(MF, FI));
}
const ArgDataPair ADP = {ArgIn, Ins[i].Flags};
ArgData.push_back(ADP);
}
// 1b. CopyFromReg vararg registers.
if (IsVarArg) {
// Argument registers
static const MCPhysReg ArgRegs[] = {ARC::R0, ARC::R1, ARC::R2, ARC::R3,
ARC::R4, ARC::R5, ARC::R6, ARC::R7};
auto *AFI = MF.getInfo<ARCFunctionInfo>();
unsigned FirstVAReg = CCInfo.getFirstUnallocated(ArgRegs);
if (FirstVAReg < array_lengthof(ArgRegs)) {
int Offset = 0;
// Save remaining registers, storing higher register numbers at a higher
// address
// There are (array_lengthof(ArgRegs) - FirstVAReg) registers which
// need to be saved.
int VarFI =
MFI.CreateFixedObject((array_lengthof(ArgRegs) - FirstVAReg) * 4,
CCInfo.getNextStackOffset(), true);
AFI->setVarArgsFrameIndex(VarFI);
SDValue FIN = DAG.getFrameIndex(VarFI, MVT::i32);
for (unsigned i = FirstVAReg; i < array_lengthof(ArgRegs); i++) {
// Move argument from phys reg -> virt reg
unsigned VReg = RegInfo.createVirtualRegister(&ARC::GPR32RegClass);
RegInfo.addLiveIn(ArgRegs[i], VReg);
SDValue Val = DAG.getCopyFromReg(Chain, dl, VReg, MVT::i32);
CFRegNode.push_back(Val.getValue(Val->getNumValues() - 1));
SDValue VAObj = DAG.getNode(ISD::ADD, dl, MVT::i32, FIN,
DAG.getConstant(Offset, dl, MVT::i32));
// Move argument from virt reg -> stack
SDValue Store =
DAG.getStore(Val.getValue(1), dl, Val, VAObj, MachinePointerInfo());
MemOps.push_back(Store);
Offset += 4;
}
} else {
llvm_unreachable("Too many var args parameters.");
}
}
// 2. Chain CopyFromReg nodes into a TokenFactor.
if (!CFRegNode.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, CFRegNode);
// 3. Memcpy 'byVal' args & push final InVals.
// Aggregates passed "byVal" need to be copied by the callee.
// The callee will use a pointer to this copy, rather than the original
// pointer.
for (const auto &ArgDI : ArgData) {
if (ArgDI.Flags.isByVal() && ArgDI.Flags.getByValSize()) {
unsigned Size = ArgDI.Flags.getByValSize();
Align Alignment =
std::max(Align(StackSlotSize), ArgDI.Flags.getNonZeroByValAlign());
// Create a new object on the stack and copy the pointee into it.
int FI = MFI.CreateStackObject(Size, Alignment, false);
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
InVals.push_back(FIN);
MemOps.push_back(DAG.getMemcpy(
Chain, dl, FIN, ArgDI.SDV, DAG.getConstant(Size, dl, MVT::i32),
Alignment, false, false, false, MachinePointerInfo(),
MachinePointerInfo()));
} else {
InVals.push_back(ArgDI.SDV);
}
}
// 4. Chain mem ops nodes into a TokenFactor.
if (!MemOps.empty()) {
MemOps.push_back(Chain);
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOps);
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//
bool ARCTargetLowering::CanLowerReturn(
CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, Context);
if (!CCInfo.CheckReturn(Outs, RetCC_ARC))
return false;
if (CCInfo.getNextStackOffset() != 0 && IsVarArg)
return false;
return true;
}
SDValue
ARCTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
const SDLoc &dl, SelectionDAG &DAG) const {
auto *AFI = DAG.getMachineFunction().getInfo<ARCFunctionInfo>();
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
// CCValAssign - represent the assignment of
// the return value to a location
SmallVector<CCValAssign, 16> RVLocs;
// CCState - Info about the registers and stack slot.
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), RVLocs,
*DAG.getContext());
// Analyze return values.
if (!IsVarArg)
CCInfo.AllocateStack(AFI->getReturnStackOffset(), Align(4));
CCInfo.AnalyzeReturn(Outs, RetCC_ARC);
SDValue Flag;
SmallVector<SDValue, 4> RetOps(1, Chain);
SmallVector<SDValue, 4> MemOpChains;
// Handle return values that must be copied to memory.
for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
CCValAssign &VA = RVLocs[i];
if (VA.isRegLoc())
continue;
assert(VA.isMemLoc());
if (IsVarArg) {
report_fatal_error("Can't return value from vararg function in memory");
}
int Offset = VA.getLocMemOffset();
unsigned ObjSize = VA.getLocVT().getStoreSize();
// Create the frame index object for the memory location.
int FI = MFI.CreateFixedObject(ObjSize, Offset, false);
// Create a SelectionDAG node corresponding to a store
// to this memory location.
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
MemOpChains.push_back(DAG.getStore(
Chain, dl, OutVals[i], FIN,
MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI)));
}
// Transform all store nodes into one single node because
// all stores are independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, MemOpChains);
// Now handle return values copied to registers.
for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
CCValAssign &VA = RVLocs[i];
if (!VA.isRegLoc())
continue;
// Copy the result values into the output registers.
Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), OutVals[i], Flag);
// guarantee that all emitted copies are
// stuck together, avoiding something bad
Flag = Chain.getValue(1);
RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
}
RetOps[0] = Chain; // Update chain.
// Add the flag if we have it.
if (Flag.getNode())
RetOps.push_back(Flag);
// What to do with the RetOps?
return DAG.getNode(ARCISD::RET, dl, MVT::Other, RetOps);
}
//===----------------------------------------------------------------------===//
// Target Optimization Hooks
//===----------------------------------------------------------------------===//
SDValue ARCTargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
return {};
}
//===----------------------------------------------------------------------===//
// Addressing mode description hooks
//===----------------------------------------------------------------------===//
/// Return true if the addressing mode represented by AM is legal for this
/// target, for a load/store of the specified type.
bool ARCTargetLowering::isLegalAddressingMode(const DataLayout &DL,
const AddrMode &AM, Type *Ty,
unsigned AS,
Instruction *I) const {
return AM.Scale == 0;
}
// Don't emit tail calls for the time being.
bool ARCTargetLowering::mayBeEmittedAsTailCall(const CallInst *CI) const {
return false;
}
SDValue ARCTargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
const ARCRegisterInfo &ARI = *Subtarget.getRegisterInfo();
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo &MFI = MF.getFrameInfo();
MFI.setFrameAddressIsTaken(true);
EVT VT = Op.getValueType();
SDLoc dl(Op);
assert(cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() == 0 &&
"Only support lowering frame addr of current frame.");
Register FrameReg = ARI.getFrameRegister(MF);
return DAG.getCopyFromReg(DAG.getEntryNode(), dl, FrameReg, VT);
}
SDValue ARCTargetLowering::LowerGlobalAddress(SDValue Op,
SelectionDAG &DAG) const {
const GlobalAddressSDNode *GN = cast<GlobalAddressSDNode>(Op);
const GlobalValue *GV = GN->getGlobal();
SDLoc dl(GN);
int64_t Offset = GN->getOffset();
SDValue GA = DAG.getTargetGlobalAddress(GV, dl, MVT::i32, Offset);
return DAG.getNode(ARCISD::GAWRAPPER, dl, MVT::i32, GA);
}
static SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG) {
MachineFunction &MF = DAG.getMachineFunction();
auto *FuncInfo = MF.getInfo<ARCFunctionInfo>();
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
SDLoc dl(Op);
EVT PtrVT = DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout());
SDValue FR = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(), PtrVT);
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
return DAG.getStore(Op.getOperand(0), dl, FR, Op.getOperand(1),
MachinePointerInfo(SV));
}
SDValue ARCTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
switch (Op.getOpcode()) {
case ISD::GlobalAddress:
return LowerGlobalAddress(Op, DAG);
case ISD::FRAMEADDR:
return LowerFRAMEADDR(Op, DAG);
case ISD::SELECT_CC:
return LowerSELECT_CC(Op, DAG);
case ISD::BR_CC:
return LowerBR_CC(Op, DAG);
case ISD::SIGN_EXTEND_INREG:
return LowerSIGN_EXTEND_INREG(Op, DAG);
case ISD::JumpTable:
return LowerJumpTable(Op, DAG);
case ISD::VASTART:
return LowerVASTART(Op, DAG);
case ISD::READCYCLECOUNTER:
// As of LLVM 3.8, the lowering code insists that we customize it even
// though we've declared the i32 version as legal. This is because it only
// thinks i64 is the truly supported version. We've already converted the
// i64 version to a widened i32.
assert(Op.getSimpleValueType() == MVT::i32);
return Op;
default:
llvm_unreachable("unimplemented operand");
}
}