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clang-p2996/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
Amara Emerson 8bde5e58c0 Delay outgoing register assignments to last. 
The delayed stack protector feature which is currently used for SDAG (and thus
allows for more commonly generating tail calls) depends on being able to extract
the tail call into a separate return block. To do this it also has to extract
the vreg->physreg copies that set up the call's arguments, since if it doesn't
then the call inst ends up using undefined physregs in it's new spliced block.

SelectionDAG implementations can do this because they delay emitting register
copies until  *after* the stack arguments are set up. GISel however just
processes and emits the arguments in IR order, so stack arguments always end up
last, and thus this breaks the code that looks for any register arg copies that
precede the call instruction.

This patch adds a thunk argument to the assignValueToReg() and custom assignment
hooks. For outgoing arguments, register assignments use this return param to
return a thunk that does the actual generating of the copies. We collect these
until all the outgoing stack assignments have been done and then execute them,
so that the copies (and perhaps some artifacts like G_SEXTs) are placed after
any stores.

Differential Revision: https://reviews.llvm.org/D110610
2021-10-04 12:33:20 -07:00

1200 lines
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//===-- lib/CodeGen/GlobalISel/CallLowering.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 some simple delegations needed for call lowering.
///
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/GlobalISel/CallLowering.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Target/TargetMachine.h"
#define DEBUG_TYPE "call-lowering"
using namespace llvm;
void CallLowering::anchor() {}
/// Helper function which updates \p Flags when \p AttrFn returns true.
static void
addFlagsUsingAttrFn(ISD::ArgFlagsTy &Flags,
const std::function<bool(Attribute::AttrKind)> &AttrFn) {
if (AttrFn(Attribute::SExt))
Flags.setSExt();
if (AttrFn(Attribute::ZExt))
Flags.setZExt();
if (AttrFn(Attribute::InReg))
Flags.setInReg();
if (AttrFn(Attribute::StructRet))
Flags.setSRet();
if (AttrFn(Attribute::Nest))
Flags.setNest();
if (AttrFn(Attribute::ByVal))
Flags.setByVal();
if (AttrFn(Attribute::Preallocated))
Flags.setPreallocated();
if (AttrFn(Attribute::InAlloca))
Flags.setInAlloca();
if (AttrFn(Attribute::Returned))
Flags.setReturned();
if (AttrFn(Attribute::SwiftSelf))
Flags.setSwiftSelf();
if (AttrFn(Attribute::SwiftAsync))
Flags.setSwiftAsync();
if (AttrFn(Attribute::SwiftError))
Flags.setSwiftError();
}
ISD::ArgFlagsTy CallLowering::getAttributesForArgIdx(const CallBase &Call,
unsigned ArgIdx) const {
ISD::ArgFlagsTy Flags;
addFlagsUsingAttrFn(Flags, [&Call, &ArgIdx](Attribute::AttrKind Attr) {
return Call.paramHasAttr(ArgIdx, Attr);
});
return Flags;
}
void CallLowering::addArgFlagsFromAttributes(ISD::ArgFlagsTy &Flags,
const AttributeList &Attrs,
unsigned OpIdx) const {
addFlagsUsingAttrFn(Flags, [&Attrs, &OpIdx](Attribute::AttrKind Attr) {
return Attrs.hasAttributeAtIndex(OpIdx, Attr);
});
}
bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, const CallBase &CB,
ArrayRef<Register> ResRegs,
ArrayRef<ArrayRef<Register>> ArgRegs,
Register SwiftErrorVReg,
std::function<unsigned()> GetCalleeReg) const {
CallLoweringInfo Info;
const DataLayout &DL = MIRBuilder.getDataLayout();
MachineFunction &MF = MIRBuilder.getMF();
bool CanBeTailCalled = CB.isTailCall() &&
isInTailCallPosition(CB, MF.getTarget()) &&
(MF.getFunction()
.getFnAttribute("disable-tail-calls")
.getValueAsString() != "true");
CallingConv::ID CallConv = CB.getCallingConv();
Type *RetTy = CB.getType();
bool IsVarArg = CB.getFunctionType()->isVarArg();
SmallVector<BaseArgInfo, 4> SplitArgs;
getReturnInfo(CallConv, RetTy, CB.getAttributes(), SplitArgs, DL);
Info.CanLowerReturn = canLowerReturn(MF, CallConv, SplitArgs, IsVarArg);
if (!Info.CanLowerReturn) {
// Callee requires sret demotion.
insertSRetOutgoingArgument(MIRBuilder, CB, Info);
// The sret demotion isn't compatible with tail-calls, since the sret
// argument points into the caller's stack frame.
CanBeTailCalled = false;
}
// First step is to marshall all the function's parameters into the correct
// physregs and memory locations. Gather the sequence of argument types that
// we'll pass to the assigner function.
unsigned i = 0;
unsigned NumFixedArgs = CB.getFunctionType()->getNumParams();
for (auto &Arg : CB.args()) {
ArgInfo OrigArg{ArgRegs[i], *Arg.get(), i, getAttributesForArgIdx(CB, i),
i < NumFixedArgs};
setArgFlags(OrigArg, i + AttributeList::FirstArgIndex, DL, CB);
// If we have an explicit sret argument that is an Instruction, (i.e., it
// might point to function-local memory), we can't meaningfully tail-call.
if (OrigArg.Flags[0].isSRet() && isa<Instruction>(&Arg))
CanBeTailCalled = false;
Info.OrigArgs.push_back(OrigArg);
++i;
}
// Try looking through a bitcast from one function type to another.
// Commonly happens with calls to objc_msgSend().
const Value *CalleeV = CB.getCalledOperand()->stripPointerCasts();
if (const Function *F = dyn_cast<Function>(CalleeV))
Info.Callee = MachineOperand::CreateGA(F, 0);
else
Info.Callee = MachineOperand::CreateReg(GetCalleeReg(), false);
Info.OrigRet = ArgInfo{ResRegs, RetTy, 0, ISD::ArgFlagsTy{}};
if (!Info.OrigRet.Ty->isVoidTy())
setArgFlags(Info.OrigRet, AttributeList::ReturnIndex, DL, CB);
Info.CB = &CB;
Info.KnownCallees = CB.getMetadata(LLVMContext::MD_callees);
Info.CallConv = CallConv;
Info.SwiftErrorVReg = SwiftErrorVReg;
Info.IsMustTailCall = CB.isMustTailCall();
Info.IsTailCall = CanBeTailCalled;
Info.IsVarArg = IsVarArg;
return lowerCall(MIRBuilder, Info);
}
template <typename FuncInfoTy>
void CallLowering::setArgFlags(CallLowering::ArgInfo &Arg, unsigned OpIdx,
const DataLayout &DL,
const FuncInfoTy &FuncInfo) const {
auto &Flags = Arg.Flags[0];
const AttributeList &Attrs = FuncInfo.getAttributes();
addArgFlagsFromAttributes(Flags, Attrs, OpIdx);
PointerType *PtrTy = dyn_cast<PointerType>(Arg.Ty->getScalarType());
if (PtrTy) {
Flags.setPointer();
Flags.setPointerAddrSpace(PtrTy->getPointerAddressSpace());
}
Align MemAlign = DL.getABITypeAlign(Arg.Ty);
if (Flags.isByVal() || Flags.isInAlloca() || Flags.isPreallocated()) {
assert(OpIdx >= AttributeList::FirstArgIndex);
unsigned ParamIdx = OpIdx - AttributeList::FirstArgIndex;
Type *ElementTy = FuncInfo.getParamByValType(ParamIdx);
if (!ElementTy)
ElementTy = FuncInfo.getParamInAllocaType(ParamIdx);
if (!ElementTy)
ElementTy = FuncInfo.getParamPreallocatedType(ParamIdx);
assert(ElementTy && "Must have byval, inalloca or preallocated type");
Flags.setByValSize(DL.getTypeAllocSize(ElementTy));
// For ByVal, alignment should be passed from FE. BE will guess if
// this info is not there but there are cases it cannot get right.
if (auto ParamAlign = FuncInfo.getParamStackAlign(ParamIdx))
MemAlign = *ParamAlign;
else if ((ParamAlign = FuncInfo.getParamAlign(ParamIdx)))
MemAlign = *ParamAlign;
else
MemAlign = Align(getTLI()->getByValTypeAlignment(ElementTy, DL));
} else if (OpIdx >= AttributeList::FirstArgIndex) {
if (auto ParamAlign =
FuncInfo.getParamStackAlign(OpIdx - AttributeList::FirstArgIndex))
MemAlign = *ParamAlign;
}
Flags.setMemAlign(MemAlign);
Flags.setOrigAlign(DL.getABITypeAlign(Arg.Ty));
// Don't try to use the returned attribute if the argument is marked as
// swiftself, since it won't be passed in x0.
if (Flags.isSwiftSelf())
Flags.setReturned(false);
}
template void
CallLowering::setArgFlags<Function>(CallLowering::ArgInfo &Arg, unsigned OpIdx,
const DataLayout &DL,
const Function &FuncInfo) const;
template void
CallLowering::setArgFlags<CallBase>(CallLowering::ArgInfo &Arg, unsigned OpIdx,
const DataLayout &DL,
const CallBase &FuncInfo) const;
void CallLowering::splitToValueTypes(const ArgInfo &OrigArg,
SmallVectorImpl<ArgInfo> &SplitArgs,
const DataLayout &DL,
CallingConv::ID CallConv,
SmallVectorImpl<uint64_t> *Offsets) const {
LLVMContext &Ctx = OrigArg.Ty->getContext();
SmallVector<EVT, 4> SplitVTs;
ComputeValueVTs(*TLI, DL, OrigArg.Ty, SplitVTs, Offsets, 0);
if (SplitVTs.size() == 0)
return;
if (SplitVTs.size() == 1) {
// No splitting to do, but we want to replace the original type (e.g. [1 x
// double] -> double).
SplitArgs.emplace_back(OrigArg.Regs[0], SplitVTs[0].getTypeForEVT(Ctx),
OrigArg.OrigArgIndex, OrigArg.Flags[0],
OrigArg.IsFixed, OrigArg.OrigValue);
return;
}
// Create one ArgInfo for each virtual register in the original ArgInfo.
assert(OrigArg.Regs.size() == SplitVTs.size() && "Regs / types mismatch");
bool NeedsRegBlock = TLI->functionArgumentNeedsConsecutiveRegisters(
OrigArg.Ty, CallConv, false, DL);
for (unsigned i = 0, e = SplitVTs.size(); i < e; ++i) {
Type *SplitTy = SplitVTs[i].getTypeForEVT(Ctx);
SplitArgs.emplace_back(OrigArg.Regs[i], SplitTy, OrigArg.OrigArgIndex,
OrigArg.Flags[0], OrigArg.IsFixed);
if (NeedsRegBlock)
SplitArgs.back().Flags[0].setInConsecutiveRegs();
}
SplitArgs.back().Flags[0].setInConsecutiveRegsLast();
}
/// 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);
}
// We need to create an unmerge to the result registers, which may require
// widening the original value.
Register UnmergeSrcReg;
if (LCMTy != PartLLT) {
// e.g. A <3 x s16> value was split to <2 x s16>
// %register_value0:_(<2 x s16>)
// %register_value1:_(<2 x s16>)
// %undef:_(<2 x s16>) = G_IMPLICIT_DEF
// %concat:_<6 x s16>) = G_CONCAT_VECTORS %reg_value0, %reg_value1, %undef
// %dst_reg:_(<3 x s16>), %dead:_(<3 x s16>) = G_UNMERGE_VALUES %concat
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());
UnmergeSrcReg = B.buildConcatVectors(LCMTy, WidenedSrcs).getReg(0);
} else {
// We don't need to widen anything if we're extracting a scalar which was
// promoted to a vector e.g. s8 -> v4s8 -> s8
assert(SrcRegs.size() == 1);
UnmergeSrcReg = SrcRegs[0];
}
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, UnmergeSrcReg);
}
/// Create a sequence of instructions to combine pieces split into register
/// typed values to the original IR value. \p OrigRegs contains the destination
/// value registers of type \p LLTy, and \p Regs contains the legalized pieces
/// with type \p PartLLT. This is used for incoming values (physregs to vregs).
static void buildCopyFromRegs(MachineIRBuilder &B, ArrayRef<Register> OrigRegs,
ArrayRef<Register> Regs, LLT LLTy, LLT PartLLT,
const ISD::ArgFlagsTy Flags) {
MachineRegisterInfo &MRI = *B.getMRI();
if (PartLLT == LLTy) {
// We should have avoided introducing a new virtual register, and just
// directly assigned here.
assert(OrigRegs[0] == Regs[0]);
return;
}
if (PartLLT.getSizeInBits() == LLTy.getSizeInBits() && OrigRegs.size() == 1 &&
Regs.size() == 1) {
B.buildBitcast(OrigRegs[0], Regs[0]);
return;
}
// A vector PartLLT needs extending to LLTy's element size.
// E.g. <2 x s64> = G_SEXT <2 x s32>.
if (PartLLT.isVector() == LLTy.isVector() &&
PartLLT.getScalarSizeInBits() > LLTy.getScalarSizeInBits() &&
(!PartLLT.isVector() ||
PartLLT.getNumElements() == LLTy.getNumElements()) &&
OrigRegs.size() == 1 && Regs.size() == 1) {
Register SrcReg = Regs[0];
LLT LocTy = MRI.getType(SrcReg);
if (Flags.isSExt()) {
SrcReg = B.buildAssertSExt(LocTy, SrcReg, LLTy.getScalarSizeInBits())
.getReg(0);
} else if (Flags.isZExt()) {
SrcReg = B.buildAssertZExt(LocTy, SrcReg, LLTy.getScalarSizeInBits())
.getReg(0);
}
// Sometimes pointers are passed zero extended.
LLT OrigTy = MRI.getType(OrigRegs[0]);
if (OrigTy.isPointer()) {
LLT IntPtrTy = LLT::scalar(OrigTy.getSizeInBits());
B.buildIntToPtr(OrigRegs[0], B.buildTrunc(IntPtrTy, SrcReg));
return;
}
B.buildTrunc(OrigRegs[0], SrcReg);
return;
}
if (!LLTy.isVector() && !PartLLT.isVector()) {
assert(OrigRegs.size() == 1);
LLT OrigTy = MRI.getType(OrigRegs[0]);
unsigned SrcSize = PartLLT.getSizeInBits().getFixedSize() * 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 (PartLLT.isVector()) {
assert(OrigRegs.size() == 1);
SmallVector<Register> CastRegs(Regs.begin(), Regs.end());
// If PartLLT is a mismatched vector in both number of elements and element
// size, e.g. PartLLT == v2s64 and LLTy is v3s32, then first coerce it to
// have the same elt type, i.e. v4s32.
if (PartLLT.getSizeInBits() > LLTy.getSizeInBits() &&
PartLLT.getScalarSizeInBits() == LLTy.getScalarSizeInBits() * 2 &&
Regs.size() == 1) {
LLT NewTy = PartLLT.changeElementType(LLTy.getElementType())
.changeElementCount(PartLLT.getElementCount() * 2);
CastRegs[0] = B.buildBitcast(NewTy, Regs[0]).getReg(0);
PartLLT = NewTy;
}
if (LLTy.getScalarType() == PartLLT.getElementType()) {
mergeVectorRegsToResultRegs(B, OrigRegs, CastRegs);
} else {
unsigned I = 0;
LLT GCDTy = getGCDType(LLTy, PartLLT);
// We are both splitting a vector, and bitcasting its element types. Cast
// the source pieces into the appropriate number of pieces with the result
// element type.
for (Register SrcReg : CastRegs)
CastRegs[I++] = B.buildBitcast(GCDTy, SrcReg).getReg(0);
mergeVectorRegsToResultRegs(B, OrigRegs, CastRegs);
}
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.
// FIXME: Should handle floating point promotions.
LLT BVType = LLT::fixed_vector(LLTy.getNumElements(), PartLLT);
auto BV = B.buildBuildVector(BVType, Regs);
B.buildTrunc(OrigRegs[0], BV);
}
}
/// Create a sequence of instructions to expand the value in \p SrcReg (of type
/// \p SrcTy) to the types in \p DstRegs (of type \p PartTy). \p ExtendOp should
/// contain the type of scalar value extension if necessary.
///
/// This is used for outgoing values (vregs to physregs)
static void buildCopyToRegs(MachineIRBuilder &B, ArrayRef<Register> DstRegs,
Register SrcReg, LLT SrcTy, LLT PartTy,
unsigned ExtendOp = TargetOpcode::G_ANYEXT) {
// We could just insert a regular copy, but this is unreachable at the moment.
assert(SrcTy != PartTy && "identical part types shouldn't reach here");
const unsigned PartSize = PartTy.getSizeInBits();
if (PartTy.isVector() == SrcTy.isVector() &&
PartTy.getScalarSizeInBits() > SrcTy.getScalarSizeInBits()) {
assert(DstRegs.size() == 1);
B.buildInstr(ExtendOp, {DstRegs[0]}, {SrcReg});
return;
}
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;
}
LLT GCDTy = getGCDType(SrcTy, PartTy);
if (GCDTy == PartTy) {
// If this already evenly divisible, we can create a simple unmerge.
B.buildUnmerge(DstRegs, SrcReg);
return;
}
MachineRegisterInfo &MRI = *B.getMRI();
LLT DstTy = MRI.getType(DstRegs[0]);
LLT LCMTy = getLCMType(SrcTy, PartTy);
const unsigned DstSize = DstTy.getSizeInBits();
const unsigned SrcSize = SrcTy.getSizeInBits();
unsigned CoveringSize = LCMTy.getSizeInBits();
Register UnmergeSrc = SrcReg;
if (CoveringSize != SrcSize) {
// For scalars, it's common to be able to use a simple extension.
if (SrcTy.isScalar() && DstTy.isScalar()) {
CoveringSize = alignTo(SrcSize, DstSize);
LLT CoverTy = LLT::scalar(CoveringSize);
UnmergeSrc = B.buildInstr(ExtendOp, {CoverTy}, {SrcReg}).getReg(0);
} else {
// Widen to the common type.
// FIXME: This should respect the extend type
Register Undef = B.buildUndef(SrcTy).getReg(0);
SmallVector<Register, 8> MergeParts(1, SrcReg);
for (unsigned Size = SrcSize; Size != CoveringSize; Size += SrcSize)
MergeParts.push_back(Undef);
UnmergeSrc = B.buildMerge(LCMTy, MergeParts).getReg(0);
}
}
// Unmerge to the original registers and pad with dead defs.
SmallVector<Register, 8> UnmergeResults(DstRegs.begin(), DstRegs.end());
for (unsigned Size = DstSize * DstRegs.size(); Size != CoveringSize;
Size += DstSize) {
UnmergeResults.push_back(MRI.createGenericVirtualRegister(DstTy));
}
B.buildUnmerge(UnmergeResults, UnmergeSrc);
}
bool CallLowering::determineAndHandleAssignments(
ValueHandler &Handler, ValueAssigner &Assigner,
SmallVectorImpl<ArgInfo> &Args, MachineIRBuilder &MIRBuilder,
CallingConv::ID CallConv, bool IsVarArg, Register ThisReturnReg) const {
MachineFunction &MF = MIRBuilder.getMF();
const Function &F = MF.getFunction();
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, F.getContext());
if (!determineAssignments(Assigner, Args, CCInfo))
return false;
return handleAssignments(Handler, Args, CCInfo, ArgLocs, MIRBuilder,
ThisReturnReg);
}
static unsigned extendOpFromFlags(llvm::ISD::ArgFlagsTy Flags) {
if (Flags.isSExt())
return TargetOpcode::G_SEXT;
if (Flags.isZExt())
return TargetOpcode::G_ZEXT;
return TargetOpcode::G_ANYEXT;
}
bool CallLowering::determineAssignments(ValueAssigner &Assigner,
SmallVectorImpl<ArgInfo> &Args,
CCState &CCInfo) const {
LLVMContext &Ctx = CCInfo.getContext();
const CallingConv::ID CallConv = CCInfo.getCallingConv();
unsigned NumArgs = Args.size();
for (unsigned i = 0; i != NumArgs; ++i) {
EVT CurVT = EVT::getEVT(Args[i].Ty);
MVT NewVT = TLI->getRegisterTypeForCallingConv(Ctx, CallConv, CurVT);
// If we need to split the type over multiple regs, check it's a scenario
// we currently support.
unsigned NumParts =
TLI->getNumRegistersForCallingConv(Ctx, CallConv, CurVT);
if (NumParts == 1) {
// Try to use the register type if we couldn't assign the VT.
if (Assigner.assignArg(i, CurVT, NewVT, NewVT, CCValAssign::Full, Args[i],
Args[i].Flags[0], CCInfo))
return false;
continue;
}
// For incoming arguments (physregs to vregs), we could have values in
// physregs (or memlocs) which we want to extract and copy to vregs.
// During this, we might have to deal with the LLT being split across
// multiple regs, so we have to record this information for later.
//
// If we have outgoing args, then we have the opposite case. We have a
// vreg with an LLT which we want to assign to a physical location, and
// we might have to record that the value has to be split later.
// We're handling an incoming arg which is split over multiple regs.
// E.g. passing an s128 on AArch64.
ISD::ArgFlagsTy OrigFlags = Args[i].Flags[0];
Args[i].Flags.clear();
for (unsigned Part = 0; Part < NumParts; ++Part) {
ISD::ArgFlagsTy Flags = OrigFlags;
if (Part == 0) {
Flags.setSplit();
} else {
Flags.setOrigAlign(Align(1));
if (Part == NumParts - 1)
Flags.setSplitEnd();
}
Args[i].Flags.push_back(Flags);
if (Assigner.assignArg(i, CurVT, NewVT, NewVT, CCValAssign::Full, Args[i],
Args[i].Flags[Part], CCInfo)) {
// Still couldn't assign this smaller part type for some reason.
return false;
}
}
}
return true;
}
bool CallLowering::handleAssignments(ValueHandler &Handler,
SmallVectorImpl<ArgInfo> &Args,
CCState &CCInfo,
SmallVectorImpl<CCValAssign> &ArgLocs,
MachineIRBuilder &MIRBuilder,
Register ThisReturnReg) const {
MachineFunction &MF = MIRBuilder.getMF();
MachineRegisterInfo &MRI = MF.getRegInfo();
const Function &F = MF.getFunction();
const DataLayout &DL = F.getParent()->getDataLayout();
const unsigned NumArgs = Args.size();
// Stores thunks for outgoing register assignments. This is used so we delay
// generating register copies until mem loc assignments are done. We do this
// so that if the target is using the delayed stack protector feature, we can
// find the split point of the block accurately. E.g. if we have:
// G_STORE %val, %memloc
// $x0 = COPY %foo
// $x1 = COPY %bar
// CALL func
// ... then the split point for the block will correctly be at, and including,
// the copy to $x0. If instead the G_STORE instruction immediately precedes
// the CALL, then we'd prematurely choose the CALL as the split point, thus
// generating a split block with a CALL that uses undefined physregs.
SmallVector<std::function<void()>> DelayedOutgoingRegAssignments;
for (unsigned i = 0, j = 0; i != NumArgs; ++i, ++j) {
assert(j < ArgLocs.size() && "Skipped too many arg locs");
CCValAssign &VA = ArgLocs[j];
assert(VA.getValNo() == i && "Location doesn't correspond to current arg");
if (VA.needsCustom()) {
std::function<void()> Thunk;
unsigned NumArgRegs = Handler.assignCustomValue(
Args[i], makeArrayRef(ArgLocs).slice(j), &Thunk);
if (Thunk)
DelayedOutgoingRegAssignments.emplace_back(Thunk);
if (!NumArgRegs)
return false;
j += NumArgRegs;
continue;
}
const MVT ValVT = VA.getValVT();
const MVT LocVT = VA.getLocVT();
const LLT LocTy(LocVT);
const LLT ValTy(ValVT);
const LLT NewLLT = Handler.isIncomingArgumentHandler() ? LocTy : ValTy;
const EVT OrigVT = EVT::getEVT(Args[i].Ty);
const LLT OrigTy = getLLTForType(*Args[i].Ty, DL);
// Expected to be multiple regs for a single incoming arg.
// There should be Regs.size() ArgLocs per argument.
// This should be the same as getNumRegistersForCallingConv
const unsigned NumParts = Args[i].Flags.size();
// Now split the registers into the assigned types.
Args[i].OrigRegs.assign(Args[i].Regs.begin(), Args[i].Regs.end());
if (NumParts != 1 || NewLLT != OrigTy) {
// If we can't directly assign the register, we need one or more
// intermediate values.
Args[i].Regs.resize(NumParts);
// For each split register, create and assign a vreg that will store
// the incoming component of the larger value. These will later be
// merged to form the final vreg.
for (unsigned Part = 0; Part < NumParts; ++Part)
Args[i].Regs[Part] = MRI.createGenericVirtualRegister(NewLLT);
}
assert((j + (NumParts - 1)) < ArgLocs.size() &&
"Too many regs for number of args");
// Coerce into outgoing value types before register assignment.
if (!Handler.isIncomingArgumentHandler() && OrigTy != ValTy) {
assert(Args[i].OrigRegs.size() == 1);
buildCopyToRegs(MIRBuilder, Args[i].Regs, Args[i].OrigRegs[0], OrigTy,
ValTy, extendOpFromFlags(Args[i].Flags[0]));
}
for (unsigned Part = 0; Part < NumParts; ++Part) {
Register ArgReg = Args[i].Regs[Part];
// There should be Regs.size() ArgLocs per argument.
VA = ArgLocs[j + Part];
const ISD::ArgFlagsTy Flags = Args[i].Flags[Part];
if (VA.isMemLoc() && !Flags.isByVal()) {
// Individual pieces may have been spilled to the stack and others
// passed in registers.
// TODO: The memory size may be larger than the value we need to
// store. We may need to adjust the offset for big endian targets.
LLT MemTy = Handler.getStackValueStoreType(DL, VA, Flags);
MachinePointerInfo MPO;
Register StackAddr = Handler.getStackAddress(
MemTy.getSizeInBytes(), VA.getLocMemOffset(), MPO, Flags);
Handler.assignValueToAddress(Args[i], Part, StackAddr, MemTy, MPO, VA);
continue;
}
if (VA.isMemLoc() && Flags.isByVal()) {
assert(Args[i].Regs.size() == 1 &&
"didn't expect split byval pointer");
if (Handler.isIncomingArgumentHandler()) {
// We just need to copy the frame index value to the pointer.
MachinePointerInfo MPO;
Register StackAddr = Handler.getStackAddress(
Flags.getByValSize(), VA.getLocMemOffset(), MPO, Flags);
MIRBuilder.buildCopy(Args[i].Regs[0], StackAddr);
} else {
// For outgoing byval arguments, insert the implicit copy byval
// implies, such that writes in the callee do not modify the caller's
// value.
uint64_t MemSize = Flags.getByValSize();
int64_t Offset = VA.getLocMemOffset();
MachinePointerInfo DstMPO;
Register StackAddr =
Handler.getStackAddress(MemSize, Offset, DstMPO, Flags);
MachinePointerInfo SrcMPO(Args[i].OrigValue);
if (!Args[i].OrigValue) {
// We still need to accurately track the stack address space if we
// don't know the underlying value.
const LLT PtrTy = MRI.getType(StackAddr);
SrcMPO = MachinePointerInfo(PtrTy.getAddressSpace());
}
Align DstAlign = std::max(Flags.getNonZeroByValAlign(),
inferAlignFromPtrInfo(MF, DstMPO));
Align SrcAlign = std::max(Flags.getNonZeroByValAlign(),
inferAlignFromPtrInfo(MF, SrcMPO));
Handler.copyArgumentMemory(Args[i], StackAddr, Args[i].Regs[0],
DstMPO, DstAlign, SrcMPO, SrcAlign,
MemSize, VA);
}
continue;
}
assert(!VA.needsCustom() && "custom loc should have been handled already");
if (i == 0 && ThisReturnReg.isValid() &&
Handler.isIncomingArgumentHandler() &&
isTypeIsValidForThisReturn(ValVT)) {
Handler.assignValueToReg(Args[i].Regs[i], ThisReturnReg, VA);
continue;
}
if (Handler.isIncomingArgumentHandler())
Handler.assignValueToReg(ArgReg, VA.getLocReg(), VA);
else {
DelayedOutgoingRegAssignments.emplace_back([=, &Handler]() {
Handler.assignValueToReg(ArgReg, VA.getLocReg(), VA);
});
}
}
// Now that all pieces have been assigned, re-pack the register typed values
// into the original value typed registers.
if (Handler.isIncomingArgumentHandler() && OrigVT != LocVT) {
// Merge the split registers into the expected larger result vregs of
// the original call.
buildCopyFromRegs(MIRBuilder, Args[i].OrigRegs, Args[i].Regs, OrigTy,
LocTy, Args[i].Flags[0]);
}
j += NumParts - 1;
}
for (auto &Fn : DelayedOutgoingRegAssignments)
Fn();
return true;
}
void CallLowering::insertSRetLoads(MachineIRBuilder &MIRBuilder, Type *RetTy,
ArrayRef<Register> VRegs, Register DemoteReg,
int FI) const {
MachineFunction &MF = MIRBuilder.getMF();
MachineRegisterInfo &MRI = MF.getRegInfo();
const DataLayout &DL = MF.getDataLayout();
SmallVector<EVT, 4> SplitVTs;
SmallVector<uint64_t, 4> Offsets;
ComputeValueVTs(*TLI, DL, RetTy, SplitVTs, &Offsets, 0);
assert(VRegs.size() == SplitVTs.size());
unsigned NumValues = SplitVTs.size();
Align BaseAlign = DL.getPrefTypeAlign(RetTy);
Type *RetPtrTy = RetTy->getPointerTo(DL.getAllocaAddrSpace());
LLT OffsetLLTy = getLLTForType(*DL.getIntPtrType(RetPtrTy), DL);
MachinePointerInfo PtrInfo = MachinePointerInfo::getFixedStack(MF, FI);
for (unsigned I = 0; I < NumValues; ++I) {
Register Addr;
MIRBuilder.materializePtrAdd(Addr, DemoteReg, OffsetLLTy, Offsets[I]);
auto *MMO = MF.getMachineMemOperand(PtrInfo, MachineMemOperand::MOLoad,
MRI.getType(VRegs[I]),
commonAlignment(BaseAlign, Offsets[I]));
MIRBuilder.buildLoad(VRegs[I], Addr, *MMO);
}
}
void CallLowering::insertSRetStores(MachineIRBuilder &MIRBuilder, Type *RetTy,
ArrayRef<Register> VRegs,
Register DemoteReg) const {
MachineFunction &MF = MIRBuilder.getMF();
MachineRegisterInfo &MRI = MF.getRegInfo();
const DataLayout &DL = MF.getDataLayout();
SmallVector<EVT, 4> SplitVTs;
SmallVector<uint64_t, 4> Offsets;
ComputeValueVTs(*TLI, DL, RetTy, SplitVTs, &Offsets, 0);
assert(VRegs.size() == SplitVTs.size());
unsigned NumValues = SplitVTs.size();
Align BaseAlign = DL.getPrefTypeAlign(RetTy);
unsigned AS = DL.getAllocaAddrSpace();
LLT OffsetLLTy =
getLLTForType(*DL.getIntPtrType(RetTy->getPointerTo(AS)), DL);
MachinePointerInfo PtrInfo(AS);
for (unsigned I = 0; I < NumValues; ++I) {
Register Addr;
MIRBuilder.materializePtrAdd(Addr, DemoteReg, OffsetLLTy, Offsets[I]);
auto *MMO = MF.getMachineMemOperand(PtrInfo, MachineMemOperand::MOStore,
MRI.getType(VRegs[I]),
commonAlignment(BaseAlign, Offsets[I]));
MIRBuilder.buildStore(VRegs[I], Addr, *MMO);
}
}
void CallLowering::insertSRetIncomingArgument(
const Function &F, SmallVectorImpl<ArgInfo> &SplitArgs, Register &DemoteReg,
MachineRegisterInfo &MRI, const DataLayout &DL) const {
unsigned AS = DL.getAllocaAddrSpace();
DemoteReg = MRI.createGenericVirtualRegister(
LLT::pointer(AS, DL.getPointerSizeInBits(AS)));
Type *PtrTy = PointerType::get(F.getReturnType(), AS);
SmallVector<EVT, 1> ValueVTs;
ComputeValueVTs(*TLI, DL, PtrTy, ValueVTs);
// NOTE: Assume that a pointer won't get split into more than one VT.
assert(ValueVTs.size() == 1);
ArgInfo DemoteArg(DemoteReg, ValueVTs[0].getTypeForEVT(PtrTy->getContext()),
ArgInfo::NoArgIndex);
setArgFlags(DemoteArg, AttributeList::ReturnIndex, DL, F);
DemoteArg.Flags[0].setSRet();
SplitArgs.insert(SplitArgs.begin(), DemoteArg);
}
void CallLowering::insertSRetOutgoingArgument(MachineIRBuilder &MIRBuilder,
const CallBase &CB,
CallLoweringInfo &Info) const {
const DataLayout &DL = MIRBuilder.getDataLayout();
Type *RetTy = CB.getType();
unsigned AS = DL.getAllocaAddrSpace();
LLT FramePtrTy = LLT::pointer(AS, DL.getPointerSizeInBits(AS));
int FI = MIRBuilder.getMF().getFrameInfo().CreateStackObject(
DL.getTypeAllocSize(RetTy), DL.getPrefTypeAlign(RetTy), false);
Register DemoteReg = MIRBuilder.buildFrameIndex(FramePtrTy, FI).getReg(0);
ArgInfo DemoteArg(DemoteReg, PointerType::get(RetTy, AS),
ArgInfo::NoArgIndex);
setArgFlags(DemoteArg, AttributeList::ReturnIndex, DL, CB);
DemoteArg.Flags[0].setSRet();
Info.OrigArgs.insert(Info.OrigArgs.begin(), DemoteArg);
Info.DemoteStackIndex = FI;
Info.DemoteRegister = DemoteReg;
}
bool CallLowering::checkReturn(CCState &CCInfo,
SmallVectorImpl<BaseArgInfo> &Outs,
CCAssignFn *Fn) const {
for (unsigned I = 0, E = Outs.size(); I < E; ++I) {
MVT VT = MVT::getVT(Outs[I].Ty);
if (Fn(I, VT, VT, CCValAssign::Full, Outs[I].Flags[0], CCInfo))
return false;
}
return true;
}
void CallLowering::getReturnInfo(CallingConv::ID CallConv, Type *RetTy,
AttributeList Attrs,
SmallVectorImpl<BaseArgInfo> &Outs,
const DataLayout &DL) const {
LLVMContext &Context = RetTy->getContext();
ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
SmallVector<EVT, 4> SplitVTs;
ComputeValueVTs(*TLI, DL, RetTy, SplitVTs);
addArgFlagsFromAttributes(Flags, Attrs, AttributeList::ReturnIndex);
for (EVT VT : SplitVTs) {
unsigned NumParts =
TLI->getNumRegistersForCallingConv(Context, CallConv, VT);
MVT RegVT = TLI->getRegisterTypeForCallingConv(Context, CallConv, VT);
Type *PartTy = EVT(RegVT).getTypeForEVT(Context);
for (unsigned I = 0; I < NumParts; ++I) {
Outs.emplace_back(PartTy, Flags);
}
}
}
bool CallLowering::checkReturnTypeForCallConv(MachineFunction &MF) const {
const auto &F = MF.getFunction();
Type *ReturnType = F.getReturnType();
CallingConv::ID CallConv = F.getCallingConv();
SmallVector<BaseArgInfo, 4> SplitArgs;
getReturnInfo(CallConv, ReturnType, F.getAttributes(), SplitArgs,
MF.getDataLayout());
return canLowerReturn(MF, CallConv, SplitArgs, F.isVarArg());
}
bool CallLowering::parametersInCSRMatch(
const MachineRegisterInfo &MRI, const uint32_t *CallerPreservedMask,
const SmallVectorImpl<CCValAssign> &OutLocs,
const SmallVectorImpl<ArgInfo> &OutArgs) const {
for (unsigned i = 0; i < OutLocs.size(); ++i) {
auto &ArgLoc = OutLocs[i];
// If it's not a register, it's fine.
if (!ArgLoc.isRegLoc())
continue;
MCRegister PhysReg = ArgLoc.getLocReg();
// Only look at callee-saved registers.
if (MachineOperand::clobbersPhysReg(CallerPreservedMask, PhysReg))
continue;
LLVM_DEBUG(
dbgs()
<< "... Call has an argument passed in a callee-saved register.\n");
// Check if it was copied from.
const ArgInfo &OutInfo = OutArgs[i];
if (OutInfo.Regs.size() > 1) {
LLVM_DEBUG(
dbgs() << "... Cannot handle arguments in multiple registers.\n");
return false;
}
// Check if we copy the register, walking through copies from virtual
// registers. Note that getDefIgnoringCopies does not ignore copies from
// physical registers.
MachineInstr *RegDef = getDefIgnoringCopies(OutInfo.Regs[0], MRI);
if (!RegDef || RegDef->getOpcode() != TargetOpcode::COPY) {
LLVM_DEBUG(
dbgs()
<< "... Parameter was not copied into a VReg, cannot tail call.\n");
return false;
}
// Got a copy. Verify that it's the same as the register we want.
Register CopyRHS = RegDef->getOperand(1).getReg();
if (CopyRHS != PhysReg) {
LLVM_DEBUG(dbgs() << "... Callee-saved register was not copied into "
"VReg, cannot tail call.\n");
return false;
}
}
return true;
}
bool CallLowering::resultsCompatible(CallLoweringInfo &Info,
MachineFunction &MF,
SmallVectorImpl<ArgInfo> &InArgs,
ValueAssigner &CalleeAssigner,
ValueAssigner &CallerAssigner) const {
const Function &F = MF.getFunction();
CallingConv::ID CalleeCC = Info.CallConv;
CallingConv::ID CallerCC = F.getCallingConv();
if (CallerCC == CalleeCC)
return true;
SmallVector<CCValAssign, 16> ArgLocs1;
CCState CCInfo1(CalleeCC, Info.IsVarArg, MF, ArgLocs1, F.getContext());
if (!determineAssignments(CalleeAssigner, InArgs, CCInfo1))
return false;
SmallVector<CCValAssign, 16> ArgLocs2;
CCState CCInfo2(CallerCC, F.isVarArg(), MF, ArgLocs2, F.getContext());
if (!determineAssignments(CallerAssigner, InArgs, CCInfo2))
return false;
// We need the argument locations to match up exactly. If there's more in
// one than the other, then we are done.
if (ArgLocs1.size() != ArgLocs2.size())
return false;
// Make sure that each location is passed in exactly the same way.
for (unsigned i = 0, e = ArgLocs1.size(); i < e; ++i) {
const CCValAssign &Loc1 = ArgLocs1[i];
const CCValAssign &Loc2 = ArgLocs2[i];
// We need both of them to be the same. So if one is a register and one
// isn't, we're done.
if (Loc1.isRegLoc() != Loc2.isRegLoc())
return false;
if (Loc1.isRegLoc()) {
// If they don't have the same register location, we're done.
if (Loc1.getLocReg() != Loc2.getLocReg())
return false;
// They matched, so we can move to the next ArgLoc.
continue;
}
// Loc1 wasn't a RegLoc, so they both must be MemLocs. Check if they match.
if (Loc1.getLocMemOffset() != Loc2.getLocMemOffset())
return false;
}
return true;
}
LLT CallLowering::ValueHandler::getStackValueStoreType(
const DataLayout &DL, const CCValAssign &VA, ISD::ArgFlagsTy Flags) const {
const MVT ValVT = VA.getValVT();
if (ValVT != MVT::iPTR) {
LLT ValTy(ValVT);
// We lost the pointeriness going through CCValAssign, so try to restore it
// based on the flags.
if (Flags.isPointer()) {
LLT PtrTy = LLT::pointer(Flags.getPointerAddrSpace(),
ValTy.getScalarSizeInBits());
if (ValVT.isVector())
return LLT::vector(ValTy.getElementCount(), PtrTy);
return PtrTy;
}
return ValTy;
}
unsigned AddrSpace = Flags.getPointerAddrSpace();
return LLT::pointer(AddrSpace, DL.getPointerSize(AddrSpace));
}
void CallLowering::ValueHandler::copyArgumentMemory(
const ArgInfo &Arg, Register DstPtr, Register SrcPtr,
const MachinePointerInfo &DstPtrInfo, Align DstAlign,
const MachinePointerInfo &SrcPtrInfo, Align SrcAlign, uint64_t MemSize,
CCValAssign &VA) const {
MachineFunction &MF = MIRBuilder.getMF();
MachineMemOperand *SrcMMO = MF.getMachineMemOperand(
SrcPtrInfo,
MachineMemOperand::MOLoad | MachineMemOperand::MODereferenceable, MemSize,
SrcAlign);
MachineMemOperand *DstMMO = MF.getMachineMemOperand(
DstPtrInfo,
MachineMemOperand::MOStore | MachineMemOperand::MODereferenceable,
MemSize, DstAlign);
const LLT PtrTy = MRI.getType(DstPtr);
const LLT SizeTy = LLT::scalar(PtrTy.getSizeInBits());
auto SizeConst = MIRBuilder.buildConstant(SizeTy, MemSize);
MIRBuilder.buildMemCpy(DstPtr, SrcPtr, SizeConst, *DstMMO, *SrcMMO);
}
Register CallLowering::ValueHandler::extendRegister(Register ValReg,
CCValAssign &VA,
unsigned MaxSizeBits) {
LLT LocTy{VA.getLocVT()};
LLT ValTy{VA.getValVT()};
if (LocTy.getSizeInBits() == ValTy.getSizeInBits())
return ValReg;
if (LocTy.isScalar() && MaxSizeBits && MaxSizeBits < LocTy.getSizeInBits()) {
if (MaxSizeBits <= ValTy.getSizeInBits())
return ValReg;
LocTy = LLT::scalar(MaxSizeBits);
}
const LLT ValRegTy = MRI.getType(ValReg);
if (ValRegTy.isPointer()) {
// The x32 ABI wants to zero extend 32-bit pointers to 64-bit registers, so
// we have to cast to do the extension.
LLT IntPtrTy = LLT::scalar(ValRegTy.getSizeInBits());
ValReg = MIRBuilder.buildPtrToInt(IntPtrTy, ValReg).getReg(0);
}
switch (VA.getLocInfo()) {
default: break;
case CCValAssign::Full:
case CCValAssign::BCvt:
// FIXME: bitconverting between vector types may or may not be a
// nop in big-endian situations.
return ValReg;
case CCValAssign::AExt: {
auto MIB = MIRBuilder.buildAnyExt(LocTy, ValReg);
return MIB.getReg(0);
}
case CCValAssign::SExt: {
Register NewReg = MRI.createGenericVirtualRegister(LocTy);
MIRBuilder.buildSExt(NewReg, ValReg);
return NewReg;
}
case CCValAssign::ZExt: {
Register NewReg = MRI.createGenericVirtualRegister(LocTy);
MIRBuilder.buildZExt(NewReg, ValReg);
return NewReg;
}
}
llvm_unreachable("unable to extend register");
}
void CallLowering::ValueAssigner::anchor() {}
Register CallLowering::IncomingValueHandler::buildExtensionHint(CCValAssign &VA,
Register SrcReg,
LLT NarrowTy) {
switch (VA.getLocInfo()) {
case CCValAssign::LocInfo::ZExt: {
return MIRBuilder
.buildAssertZExt(MRI.cloneVirtualRegister(SrcReg), SrcReg,
NarrowTy.getScalarSizeInBits())
.getReg(0);
}
case CCValAssign::LocInfo::SExt: {
return MIRBuilder
.buildAssertSExt(MRI.cloneVirtualRegister(SrcReg), SrcReg,
NarrowTy.getScalarSizeInBits())
.getReg(0);
break;
}
default:
return SrcReg;
}
}
/// Check if we can use a basic COPY instruction between the two types.
///
/// We're currently building on top of the infrastructure using MVT, which loses
/// pointer information in the CCValAssign. We accept copies from physical
/// registers that have been reported as integers if it's to an equivalent sized
/// pointer LLT.
static bool isCopyCompatibleType(LLT SrcTy, LLT DstTy) {
if (SrcTy == DstTy)
return true;
if (SrcTy.getSizeInBits() != DstTy.getSizeInBits())
return false;
SrcTy = SrcTy.getScalarType();
DstTy = DstTy.getScalarType();
return (SrcTy.isPointer() && DstTy.isScalar()) ||
(DstTy.isScalar() && SrcTy.isPointer());
}
void CallLowering::IncomingValueHandler::assignValueToReg(Register ValVReg,
Register PhysReg,
CCValAssign VA) {
const MVT LocVT = VA.getLocVT();
const LLT LocTy(LocVT);
const LLT RegTy = MRI.getType(ValVReg);
if (isCopyCompatibleType(RegTy, LocTy)) {
MIRBuilder.buildCopy(ValVReg, PhysReg);
return;
}
auto Copy = MIRBuilder.buildCopy(LocTy, PhysReg);
auto Hint = buildExtensionHint(VA, Copy.getReg(0), RegTy);
MIRBuilder.buildTrunc(ValVReg, Hint);
}
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