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llvm-mirror/lib/Target/ARM/ARMCallLowering.cpp
Tim Northover 948ccd8eb0 GlobalISel: restrict G_EXTRACT instruction to just one operand. 
A bit more painful than G_INSERT because it was more widely used, but this
should simplify the handling of extract operations in most locations.

llvm-svn: 297100
2017-03-06 23:50:28 +00:00

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//===-- llvm/lib/Target/ARM/ARMCallLowering.cpp - Call lowering -----------===//
//
// 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 "ARMCallLowering.h"
#include "ARMBaseInstrInfo.h"
#include "ARMISelLowering.h"
#include "ARMSubtarget.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
#ifndef LLVM_BUILD_GLOBAL_ISEL
#error "This shouldn't be built without GISel"
#endif
ARMCallLowering::ARMCallLowering(const ARMTargetLowering &TLI)
: CallLowering(&TLI) {}
static bool isSupportedType(const DataLayout &DL, const ARMTargetLowering &TLI,
Type *T) {
EVT VT = TLI.getValueType(DL, T, true);
if (!VT.isSimple() || VT.isVector())
return false;
unsigned VTSize = VT.getSimpleVT().getSizeInBits();
if (VTSize == 64)
// FIXME: Support i64 too
return VT.isFloatingPoint();
return VTSize == 1 || VTSize == 8 || VTSize == 16 || VTSize == 32;
}
namespace {
/// Helper class for values going out through an ABI boundary (used for handling
/// function return values and call parameters).
struct OutgoingValueHandler : public CallLowering::ValueHandler {
OutgoingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
MachineInstrBuilder &MIB, CCAssignFn *AssignFn)
: ValueHandler(MIRBuilder, MRI, AssignFn), MIB(MIB), StackSize(0) {}
unsigned getStackAddress(uint64_t Size, int64_t Offset,
MachinePointerInfo &MPO) override {
assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
"Unsupported size");
LLT p0 = LLT::pointer(0, 32);
LLT s32 = LLT::scalar(32);
unsigned SPReg = MRI.createGenericVirtualRegister(p0);
MIRBuilder.buildCopy(SPReg, ARM::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 assignValueToReg(unsigned ValVReg, unsigned PhysReg,
CCValAssign &VA) override {
assert(VA.isRegLoc() && "Value shouldn't be assigned to reg");
assert(VA.getLocReg() == PhysReg && "Assigning to the wrong reg?");
assert(VA.getValVT().getSizeInBits() <= 64 && "Unsupported value size");
assert(VA.getLocVT().getSizeInBits() <= 64 && "Unsupported location size");
unsigned ExtReg = extendRegister(ValVReg, VA);
MIRBuilder.buildCopy(PhysReg, ExtReg);
MIB.addUse(PhysReg, RegState::Implicit);
}
void assignValueToAddress(unsigned ValVReg, unsigned Addr, uint64_t Size,
MachinePointerInfo &MPO, CCValAssign &VA) override {
assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
"Unsupported size");
unsigned ExtReg = extendRegister(ValVReg, VA);
auto MMO = MIRBuilder.getMF().getMachineMemOperand(
MPO, MachineMemOperand::MOStore, VA.getLocVT().getStoreSize(),
/* Alignment */ 0);
MIRBuilder.buildStore(ExtReg, Addr, *MMO);
}
unsigned assignCustomValue(const CallLowering::ArgInfo &Arg,
ArrayRef<CCValAssign> VAs) override {
CCValAssign VA = VAs[0];
assert(VA.needsCustom() && "Value doesn't need custom handling");
assert(VA.getValVT() == MVT::f64 && "Unsupported type");
CCValAssign NextVA = VAs[1];
assert(NextVA.needsCustom() && "Value doesn't need custom handling");
assert(NextVA.getValVT() == MVT::f64 && "Unsupported type");
assert(VA.getValNo() == NextVA.getValNo() &&
"Values belong to different arguments");
assert(VA.isRegLoc() && "Value should be in reg");
assert(NextVA.isRegLoc() && "Value should be in reg");
unsigned NewRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
MRI.createGenericVirtualRegister(LLT::scalar(32))};
MIRBuilder.buildExtract(NewRegs[0], Arg.Reg, 0);
MIRBuilder.buildExtract(NewRegs[1], Arg.Reg, 32);
bool IsLittle = MIRBuilder.getMF().getSubtarget<ARMSubtarget>().isLittle();
if (!IsLittle)
std::swap(NewRegs[0], NewRegs[1]);
assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
return 1;
}
bool assignArg(unsigned ValNo, MVT ValVT, MVT LocVT,
CCValAssign::LocInfo LocInfo,
const CallLowering::ArgInfo &Info, CCState &State) override {
if (AssignFn(ValNo, ValVT, LocVT, LocInfo, Info.Flags, State))
return true;
StackSize =
std::max(StackSize, static_cast<uint64_t>(State.getNextStackOffset()));
return false;
}
MachineInstrBuilder &MIB;
uint64_t StackSize;
};
} // End anonymous namespace.
void ARMCallLowering::splitToValueTypes(const ArgInfo &OrigArg,
SmallVectorImpl<ArgInfo> &SplitArgs,
const DataLayout &DL,
MachineRegisterInfo &MRI) const {
const ARMTargetLowering &TLI = *getTLI<ARMTargetLowering>();
LLVMContext &Ctx = OrigArg.Ty->getContext();
SmallVector<EVT, 4> SplitVTs;
SmallVector<uint64_t, 4> Offsets;
ComputeValueVTs(TLI, DL, OrigArg.Ty, SplitVTs, &Offsets, 0);
assert(SplitVTs.size() == 1 && "Unsupported type");
// Even if there is no splitting to do, we still want to replace the original
// type (e.g. pointer type -> integer).
SplitArgs.emplace_back(OrigArg.Reg, SplitVTs[0].getTypeForEVT(Ctx),
OrigArg.Flags, OrigArg.IsFixed);
}
/// Lower the return value for the already existing \p Ret. This assumes that
/// \p MIRBuilder's insertion point is correct.
bool ARMCallLowering::lowerReturnVal(MachineIRBuilder &MIRBuilder,
const Value *Val, unsigned VReg,
MachineInstrBuilder &Ret) const {
if (!Val)
// Nothing to do here.
return true;
auto &MF = MIRBuilder.getMF();
const auto &F = *MF.getFunction();
auto DL = MF.getDataLayout();
auto &TLI = *getTLI<ARMTargetLowering>();
if (!isSupportedType(DL, TLI, Val->getType()))
return false;
SmallVector<ArgInfo, 4> SplitVTs;
ArgInfo RetInfo(VReg, Val->getType());
setArgFlags(RetInfo, AttributeSet::ReturnIndex, DL, F);
splitToValueTypes(RetInfo, SplitVTs, DL, MF.getRegInfo());
CCAssignFn *AssignFn =
TLI.CCAssignFnForReturn(F.getCallingConv(), F.isVarArg());
OutgoingValueHandler RetHandler(MIRBuilder, MF.getRegInfo(), Ret, AssignFn);
return handleAssignments(MIRBuilder, SplitVTs, RetHandler);
}
bool ARMCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
const Value *Val, unsigned VReg) const {
assert(!Val == !VReg && "Return value without a vreg");
auto Ret = MIRBuilder.buildInstrNoInsert(ARM::BX_RET).add(predOps(ARMCC::AL));
if (!lowerReturnVal(MIRBuilder, Val, VReg, Ret))
return false;
MIRBuilder.insertInstr(Ret);
return true;
}
namespace {
/// Helper class for values coming in through an ABI boundary (used for handling
/// formal arguments and call return values).
struct IncomingValueHandler : public CallLowering::ValueHandler {
IncomingValueHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
CCAssignFn AssignFn)
: ValueHandler(MIRBuilder, MRI, AssignFn) {}
unsigned getStackAddress(uint64_t Size, int64_t Offset,
MachinePointerInfo &MPO) override {
assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
"Unsupported size");
auto &MFI = MIRBuilder.getMF().getFrameInfo();
int FI = MFI.CreateFixedObject(Size, Offset, true);
MPO = MachinePointerInfo::getFixedStack(MIRBuilder.getMF(), FI);
unsigned AddrReg =
MRI.createGenericVirtualRegister(LLT::pointer(MPO.getAddrSpace(), 32));
MIRBuilder.buildFrameIndex(AddrReg, FI);
return AddrReg;
}
void assignValueToAddress(unsigned ValVReg, unsigned Addr, uint64_t Size,
MachinePointerInfo &MPO, CCValAssign &VA) override {
assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
"Unsupported size");
if (VA.getLocInfo() == CCValAssign::SExt ||
VA.getLocInfo() == CCValAssign::ZExt) {
// If the value is zero- or sign-extended, its size becomes 4 bytes, so
// that's what we should load.
Size = 4;
assert(MRI.getType(ValVReg).isScalar() && "Only scalars supported atm");
MRI.setType(ValVReg, LLT::scalar(32));
}
auto MMO = MIRBuilder.getMF().getMachineMemOperand(
MPO, MachineMemOperand::MOLoad, Size, /* Alignment */ 0);
MIRBuilder.buildLoad(ValVReg, Addr, *MMO);
}
void assignValueToReg(unsigned ValVReg, unsigned PhysReg,
CCValAssign &VA) override {
assert(VA.isRegLoc() && "Value shouldn't be assigned to reg");
assert(VA.getLocReg() == PhysReg && "Assigning to the wrong reg?");
assert(VA.getValVT().getSizeInBits() <= 64 && "Unsupported value size");
assert(VA.getLocVT().getSizeInBits() <= 64 && "Unsupported location size");
// The necesary extensions are handled on the other side of the ABI
// boundary.
markPhysRegUsed(PhysReg);
MIRBuilder.buildCopy(ValVReg, PhysReg);
}
unsigned assignCustomValue(const ARMCallLowering::ArgInfo &Arg,
ArrayRef<CCValAssign> VAs) override {
CCValAssign VA = VAs[0];
assert(VA.needsCustom() && "Value doesn't need custom handling");
assert(VA.getValVT() == MVT::f64 && "Unsupported type");
CCValAssign NextVA = VAs[1];
assert(NextVA.needsCustom() && "Value doesn't need custom handling");
assert(NextVA.getValVT() == MVT::f64 && "Unsupported type");
assert(VA.getValNo() == NextVA.getValNo() &&
"Values belong to different arguments");
assert(VA.isRegLoc() && "Value should be in reg");
assert(NextVA.isRegLoc() && "Value should be in reg");
unsigned NewRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
MRI.createGenericVirtualRegister(LLT::scalar(32))};
assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
bool IsLittle = MIRBuilder.getMF().getSubtarget<ARMSubtarget>().isLittle();
if (!IsLittle)
std::swap(NewRegs[0], NewRegs[1]);
MIRBuilder.buildSequence(Arg.Reg, NewRegs, {0, 32});
return 1;
}
/// Marking a physical register as used is different between formal
/// parameters, where it's a basic block live-in, and call returns, where it's
/// an implicit-def of the call instruction.
virtual void markPhysRegUsed(unsigned PhysReg) = 0;
};
struct FormalArgHandler : public IncomingValueHandler {
FormalArgHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
CCAssignFn AssignFn)
: IncomingValueHandler(MIRBuilder, MRI, AssignFn) {}
void markPhysRegUsed(unsigned PhysReg) override {
MIRBuilder.getMBB().addLiveIn(PhysReg);
}
};
} // End anonymous namespace
bool ARMCallLowering::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;
auto &MF = MIRBuilder.getMF();
auto DL = MF.getDataLayout();
auto &TLI = *getTLI<ARMTargetLowering>();
auto Subtarget = TLI.getSubtarget();
if (Subtarget->isThumb())
return false;
// FIXME: Support soft float (when we're ready to generate libcalls)
if (Subtarget->useSoftFloat() || !Subtarget->hasVFP2())
return false;
auto &Args = F.getArgumentList();
for (auto &Arg : Args)
if (!isSupportedType(DL, TLI, Arg.getType()))
return false;
CCAssignFn *AssignFn =
TLI.CCAssignFnForCall(F.getCallingConv(), F.isVarArg());
SmallVector<ArgInfo, 8> ArgInfos;
unsigned Idx = 0;
for (auto &Arg : Args) {
ArgInfo AInfo(VRegs[Idx], Arg.getType());
setArgFlags(AInfo, Idx + 1, DL, F);
splitToValueTypes(AInfo, ArgInfos, DL, MF.getRegInfo());
Idx++;
}
FormalArgHandler ArgHandler(MIRBuilder, MIRBuilder.getMF().getRegInfo(),
AssignFn);
return handleAssignments(MIRBuilder, ArgInfos, ArgHandler);
}
namespace {
struct CallReturnHandler : public IncomingValueHandler {
CallReturnHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
MachineInstrBuilder MIB, CCAssignFn *AssignFn)
: IncomingValueHandler(MIRBuilder, MRI, AssignFn), MIB(MIB) {}
void markPhysRegUsed(unsigned PhysReg) override {
MIB.addDef(PhysReg, RegState::Implicit);
}
MachineInstrBuilder MIB;
};
} // End anonymous namespace.
bool ARMCallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
const MachineOperand &Callee,
const ArgInfo &OrigRet,
ArrayRef<ArgInfo> OrigArgs) const {
MachineFunction &MF = MIRBuilder.getMF();
const auto &TLI = *getTLI<ARMTargetLowering>();
const auto &DL = MF.getDataLayout();
const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
MachineRegisterInfo &MRI = MF.getRegInfo();
if (MF.getSubtarget<ARMSubtarget>().genLongCalls())
return false;
auto CallSeqStart = MIRBuilder.buildInstr(ARM::ADJCALLSTACKDOWN);
// FIXME: This is the calling convention of the caller - we should use the
// calling convention of the callee instead.
auto CallConv = MF.getFunction()->getCallingConv();
// Create the call instruction so we can add the implicit uses of arg
// registers, but don't insert it yet.
auto MIB = MIRBuilder.buildInstrNoInsert(ARM::BLX).add(Callee).addRegMask(
TRI->getCallPreservedMask(MF, CallConv));
SmallVector<ArgInfo, 8> ArgInfos;
for (auto Arg : OrigArgs) {
if (!isSupportedType(DL, TLI, Arg.Ty))
return false;
if (!Arg.IsFixed)
return false;
splitToValueTypes(Arg, ArgInfos, DL, MRI);
}
auto ArgAssignFn = TLI.CCAssignFnForCall(CallConv, /*IsVarArg=*/false);
OutgoingValueHandler ArgHandler(MIRBuilder, MRI, MIB, ArgAssignFn);
if (!handleAssignments(MIRBuilder, ArgInfos, ArgHandler))
return false;
// Now we can add the actual call instruction to the correct basic block.
MIRBuilder.insertInstr(MIB);
if (!OrigRet.Ty->isVoidTy()) {
if (!isSupportedType(DL, TLI, OrigRet.Ty))
return false;
ArgInfos.clear();
splitToValueTypes(OrigRet, ArgInfos, DL, MRI);
auto RetAssignFn = TLI.CCAssignFnForReturn(CallConv, /*IsVarArg=*/false);
CallReturnHandler RetHandler(MIRBuilder, MRI, MIB, RetAssignFn);
if (!handleAssignments(MIRBuilder, ArgInfos, RetHandler))
return false;
}
// We now know the size of the stack - update the ADJCALLSTACKDOWN
// accordingly.
CallSeqStart.addImm(ArgHandler.StackSize).add(predOps(ARMCC::AL));
MIRBuilder.buildInstr(ARM::ADJCALLSTACKUP)
.addImm(ArgHandler.StackSize)
.addImm(0)
.add(predOps(ARMCC::AL));
return true;
}
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