void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
SelectionDAG *DAG) {
Fn = &fn;
MF = &mf;
TLI = MF->getSubtarget().getTargetLowering();
RegInfo = &MF->getRegInfo();
MachineModuleInfo &MMI = MF->getMMI();
const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
unsigned StackAlign = TFI->getStackAlignment();
// Check whether the function can return without sret-demotion.
SmallVector<ISD::OutputArg, 4> Outs;
GetReturnInfo(Fn->getReturnType(), Fn->getAttributes(), Outs, *TLI,
mf.getDataLayout());
CanLowerReturn = TLI->CanLowerReturn(Fn->getCallingConv(), *MF,
Fn->isVarArg(), Outs, Fn->getContext());
// If this personality uses funclets, we need to do a bit more work.
DenseMap<const AllocaInst *, int *> CatchObjects;
EHPersonality Personality = classifyEHPersonality(
Fn->hasPersonalityFn() ? Fn->getPersonalityFn() : nullptr);
if (isFuncletEHPersonality(Personality)) {
// Calculate state numbers if we haven't already.
WinEHFuncInfo &EHInfo = *MF->getWinEHFuncInfo();
if (Personality == EHPersonality::MSVC_CXX)
calculateWinCXXEHStateNumbers(&fn, EHInfo);
else if (isAsynchronousEHPersonality(Personality))
calculateSEHStateNumbers(&fn, EHInfo);
else if (Personality == EHPersonality::CoreCLR)
calculateClrEHStateNumbers(&fn, EHInfo);
// Map all BB references in the WinEH data to MBBs.
for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap) {
for (WinEHHandlerType &H : TBME.HandlerArray) {
if (const AllocaInst *AI = H.CatchObj.Alloca)
CatchObjects.insert({AI, &H.CatchObj.FrameIndex});
else
H.CatchObj.FrameIndex = INT_MAX;
}
}
}
// Initialize the mapping of values to registers. This is only set up for
// instruction values that are used outside of the block that defines
// them.
Function::const_iterator BB = Fn->begin(), EB = Fn->end();
for (; BB != EB; ++BB)
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
Type *Ty = AI->getAllocatedType();
unsigned Align =
std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(Ty),
AI->getAlignment());
// Static allocas can be folded into the initial stack frame
// adjustment. For targets that don't realign the stack, don't
// do this if there is an extra alignment requirement.
if (AI->isStaticAlloca() &&
(TFI->isStackRealignable() || (Align <= StackAlign))) {
const ConstantInt *CUI = cast<ConstantInt>(AI->getArraySize());
uint64_t TySize = MF->getDataLayout().getTypeAllocSize(Ty);
TySize *= CUI->getZExtValue(); // Get total allocated size.
if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
int FrameIndex = INT_MAX;
auto Iter = CatchObjects.find(AI);
if (Iter != CatchObjects.end() && TLI->needsFixedCatchObjects()) {
FrameIndex = MF->getFrameInfo().CreateFixedObject(
TySize, 0, /*Immutable=*/false, /*isAliased=*/true);
MF->getFrameInfo().setObjectAlignment(FrameIndex, Align);
} else {
FrameIndex =
MF->getFrameInfo().CreateStackObject(TySize, Align, false, AI);
}
StaticAllocaMap[AI] = FrameIndex;
// Update the catch handler information.
if (Iter != CatchObjects.end())
*Iter->second = FrameIndex;
} else {
// FIXME: Overaligned static allocas should be grouped into
// a single dynamic allocation instead of using a separate
// stack allocation for each one.
if (Align <= StackAlign)
Align = 0;
// Inform the Frame Information that we have variable-sized objects.
MF->getFrameInfo().CreateVariableSizedObject(Align ? Align : 1, AI);
}
}
// Look for inline asm that clobbers the SP register.
if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
ImmutableCallSite CS(&*I);
if (isa<InlineAsm>(CS.getCalledValue())) {
unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
std::vector<TargetLowering::AsmOperandInfo> Ops =
TLI->ParseConstraints(Fn->getParent()->getDataLayout(), TRI, CS);
for (size_t I = 0, E = Ops.size(); I != E; ++I) {
TargetLowering::AsmOperandInfo &Op = Ops[I];
if (Op.Type == InlineAsm::isClobber) {
// Clobbers don't have SDValue operands, hence SDValue().
TLI->ComputeConstraintToUse(Op, SDValue(), DAG);
std::pair<unsigned, const TargetRegisterClass *> PhysReg =
TLI->getRegForInlineAsmConstraint(TRI, Op.ConstraintCode,
Op.ConstraintVT);
if (PhysReg.first == SP)
MF->getFrameInfo().setHasOpaqueSPAdjustment(true);
}
}
}
}
// Look for calls to the @llvm.va_start intrinsic. We can omit some
// prologue boilerplate for variadic functions that don't examine their
// arguments.
if (const auto *II = dyn_cast<IntrinsicInst>(I)) {
if (II->getIntrinsicID() == Intrinsic::vastart)
MF->getFrameInfo().setHasVAStart(true);
}
// If we have a musttail call in a variadic function, we need to ensure we
// forward implicit register parameters.
if (const auto *CI = dyn_cast<CallInst>(I)) {
if (CI->isMustTailCall() && Fn->isVarArg())
MF->getFrameInfo().setHasMustTailInVarArgFunc(true);
}
// Mark values used outside their block as exported, by allocating
// a virtual register for them.
if (isUsedOutsideOfDefiningBlock(&*I))
if (!isa<AllocaInst>(I) || !StaticAllocaMap.count(cast<AllocaInst>(I)))
InitializeRegForValue(&*I);
// Collect llvm.dbg.declare information. This is done now instead of
// during the initial isel pass through the IR so that it is done
// in a predictable order.
if (const DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(I)) {
assert(DI->getVariable() && "Missing variable");
assert(DI->getDebugLoc() && "Missing location");
if (MMI.hasDebugInfo()) {
// Don't handle byval struct arguments or VLAs, for example.
// Non-byval arguments are handled here (they refer to the stack
// temporary alloca at this point).
const Value *Address = DI->getAddress();
if (Address) {
if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
Address = BCI->getOperand(0);
if (const AllocaInst *AI = dyn_cast<AllocaInst>(Address)) {
DenseMap<const AllocaInst *, int>::iterator SI =
StaticAllocaMap.find(AI);
if (SI != StaticAllocaMap.end()) { // Check for VLAs.
int FI = SI->second;
MMI.setVariableDbgInfo(DI->getVariable(), DI->getExpression(),
FI, DI->getDebugLoc());
}
}
}
}
}
// Decide the preferred extend type for a value.
PreferredExtendType[&*I] = getPreferredExtendForValue(&*I);
}
// Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
// also creates the initial PHI MachineInstrs, though none of the input
// operands are populated.
for (BB = Fn->begin(); BB != EB; ++BB) {
// Don't create MachineBasicBlocks for imaginary EH pad blocks. These blocks
// are really data, and no instructions can live here.
if (BB->isEHPad()) {
const Instruction *I = BB->getFirstNonPHI();
// If this is a non-landingpad EH pad, mark this function as using
// funclets.
// FIXME: SEH catchpads do not create funclets, so we could avoid setting
// this in such cases in order to improve frame layout.
if (!isa<LandingPadInst>(I)) {
MMI.setHasEHFunclets(true);
MF->getFrameInfo().setHasOpaqueSPAdjustment(true);
}
if (isa<CatchSwitchInst>(I)) {
assert(&*BB->begin() == I &&
"WinEHPrepare failed to remove PHIs from imaginary BBs");
continue;
}
if (isa<FuncletPadInst>(I))
assert(&*BB->begin() == I && "WinEHPrepare failed to demote PHIs");
}
MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(&*BB);
MBBMap[&*BB] = MBB;
MF->push_back(MBB);
// Transfer the address-taken flag. This is necessary because there could
// be multiple MachineBasicBlocks corresponding to one BasicBlock, and only
// the first one should be marked.
if (BB->hasAddressTaken())
MBB->setHasAddressTaken();
// Create Machine PHI nodes for LLVM PHI nodes, lowering them as
// appropriate.
for (BasicBlock::const_iterator I = BB->begin();
const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
if (PN->use_empty()) continue;
// Skip empty types
if (PN->getType()->isEmptyTy())
continue;
DebugLoc DL = PN->getDebugLoc();
unsigned PHIReg = ValueMap[PN];
assert(PHIReg && "PHI node does not have an assigned virtual register!");
SmallVector<EVT, 4> ValueVTs;
ComputeValueVTs(*TLI, MF->getDataLayout(), PN->getType(), ValueVTs);
for (unsigned vti = 0, vte = ValueVTs.size(); vti != vte; ++vti) {
EVT VT = ValueVTs[vti];
unsigned NumRegisters = TLI->getNumRegisters(Fn->getContext(), VT);
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
for (unsigned i = 0; i != NumRegisters; ++i)
BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i);
PHIReg += NumRegisters;
}
}
}
// Mark landing pad blocks.
SmallVector<const LandingPadInst *, 4> LPads;
for (BB = Fn->begin(); BB != EB; ++BB) {
const Instruction *FNP = BB->getFirstNonPHI();
if (BB->isEHPad() && MBBMap.count(&*BB))
MBBMap[&*BB]->setIsEHPad();
if (const auto *LPI = dyn_cast<LandingPadInst>(FNP))
LPads.push_back(LPI);
}
if (!isFuncletEHPersonality(Personality))
return;
WinEHFuncInfo &EHInfo = *MF->getWinEHFuncInfo();
// Map all BB references in the WinEH data to MBBs.
for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap) {
for (WinEHHandlerType &H : TBME.HandlerArray) {
if (H.Handler)
H.Handler = MBBMap[H.Handler.get<const BasicBlock *>()];
}
}
for (CxxUnwindMapEntry &UME : EHInfo.CxxUnwindMap)
if (UME.Cleanup)
UME.Cleanup = MBBMap[UME.Cleanup.get<const BasicBlock *>()];
for (SEHUnwindMapEntry &UME : EHInfo.SEHUnwindMap) {
const BasicBlock *BB = UME.Handler.get<const BasicBlock *>();
UME.Handler = MBBMap[BB];
}
for (ClrEHUnwindMapEntry &CME : EHInfo.ClrEHUnwindMap) {
const BasicBlock *BB = CME.Handler.get<const BasicBlock *>();
CME.Handler = MBBMap[BB];
}
}
void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
SelectionDAG *DAG) {
Fn = &fn;
MF = &mf;
TLI = MF->getSubtarget().getTargetLowering();
RegInfo = &MF->getRegInfo();
MachineModuleInfo &MMI = MF->getMMI();
// Check whether the function can return without sret-demotion.
SmallVector<ISD::OutputArg, 4> Outs;
GetReturnInfo(Fn->getReturnType(), Fn->getAttributes(), Outs, *TLI,
mf.getDataLayout());
CanLowerReturn = TLI->CanLowerReturn(Fn->getCallingConv(), *MF,
Fn->isVarArg(), Outs, Fn->getContext());
// Initialize the mapping of values to registers. This is only set up for
// instruction values that are used outside of the block that defines
// them.
Function::const_iterator BB = Fn->begin(), EB = Fn->end();
for (; BB != EB; ++BB)
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) {
// Static allocas can be folded into the initial stack frame adjustment.
if (AI->isStaticAlloca()) {
const ConstantInt *CUI = cast<ConstantInt>(AI->getArraySize());
Type *Ty = AI->getAllocatedType();
uint64_t TySize = MF->getDataLayout().getTypeAllocSize(Ty);
unsigned Align =
std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(Ty),
AI->getAlignment());
TySize *= CUI->getZExtValue(); // Get total allocated size.
if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
StaticAllocaMap[AI] =
MF->getFrameInfo()->CreateStackObject(TySize, Align, false, AI);
} else {
unsigned Align =
std::max((unsigned)MF->getDataLayout().getPrefTypeAlignment(
AI->getAllocatedType()),
AI->getAlignment());
unsigned StackAlign =
MF->getSubtarget().getFrameLowering()->getStackAlignment();
if (Align <= StackAlign)
Align = 0;
// Inform the Frame Information that we have variable-sized objects.
MF->getFrameInfo()->CreateVariableSizedObject(Align ? Align : 1, AI);
}
}
// Look for inline asm that clobbers the SP register.
if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
ImmutableCallSite CS(I);
if (isa<InlineAsm>(CS.getCalledValue())) {
unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
std::vector<TargetLowering::AsmOperandInfo> Ops =
TLI->ParseConstraints(Fn->getParent()->getDataLayout(), TRI, CS);
for (size_t I = 0, E = Ops.size(); I != E; ++I) {
TargetLowering::AsmOperandInfo &Op = Ops[I];
if (Op.Type == InlineAsm::isClobber) {
// Clobbers don't have SDValue operands, hence SDValue().
TLI->ComputeConstraintToUse(Op, SDValue(), DAG);
std::pair<unsigned, const TargetRegisterClass *> PhysReg =
TLI->getRegForInlineAsmConstraint(TRI, Op.ConstraintCode,
Op.ConstraintVT);
if (PhysReg.first == SP)
MF->getFrameInfo()->setHasOpaqueSPAdjustment(true);
}
}
}
}
// Look for calls to the @llvm.va_start intrinsic. We can omit some
// prologue boilerplate for variadic functions that don't examine their
// arguments.
if (const auto *II = dyn_cast<IntrinsicInst>(I)) {
if (II->getIntrinsicID() == Intrinsic::vastart)
MF->getFrameInfo()->setHasVAStart(true);
}
// If we have a musttail call in a variadic funciton, we need to ensure we
// forward implicit register parameters.
if (const auto *CI = dyn_cast<CallInst>(I)) {
if (CI->isMustTailCall() && Fn->isVarArg())
MF->getFrameInfo()->setHasMustTailInVarArgFunc(true);
}
// Mark values used outside their block as exported, by allocating
// a virtual register for them.
if (isUsedOutsideOfDefiningBlock(I))
if (!isa<AllocaInst>(I) ||
!StaticAllocaMap.count(cast<AllocaInst>(I)))
InitializeRegForValue(I);
// Collect llvm.dbg.declare information. This is done now instead of
// during the initial isel pass through the IR so that it is done
// in a predictable order.
if (const DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(I)) {
assert(DI->getVariable() && "Missing variable");
assert(DI->getDebugLoc() && "Missing location");
if (MMI.hasDebugInfo()) {
// Don't handle byval struct arguments or VLAs, for example.
// Non-byval arguments are handled here (they refer to the stack
// temporary alloca at this point).
const Value *Address = DI->getAddress();
if (Address) {
if (const BitCastInst *BCI = dyn_cast<BitCastInst>(Address))
Address = BCI->getOperand(0);
if (const AllocaInst *AI = dyn_cast<AllocaInst>(Address)) {
DenseMap<const AllocaInst *, int>::iterator SI =
StaticAllocaMap.find(AI);
if (SI != StaticAllocaMap.end()) { // Check for VLAs.
int FI = SI->second;
MMI.setVariableDbgInfo(DI->getVariable(), DI->getExpression(),
FI, DI->getDebugLoc());
}
}
}
}
}
// Decide the preferred extend type for a value.
PreferredExtendType[I] = getPreferredExtendForValue(I);
}
// Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
// also creates the initial PHI MachineInstrs, though none of the input
// operands are populated.
for (BB = Fn->begin(); BB != EB; ++BB) {
MachineBasicBlock *MBB = mf.CreateMachineBasicBlock(BB);
MBBMap[BB] = MBB;
MF->push_back(MBB);
// Transfer the address-taken flag. This is necessary because there could
// be multiple MachineBasicBlocks corresponding to one BasicBlock, and only
// the first one should be marked.
if (BB->hasAddressTaken())
MBB->setHasAddressTaken();
// Create Machine PHI nodes for LLVM PHI nodes, lowering them as
// appropriate.
for (BasicBlock::const_iterator I = BB->begin();
const PHINode *PN = dyn_cast<PHINode>(I); ++I) {
if (PN->use_empty()) continue;
// Skip empty types
if (PN->getType()->isEmptyTy())
continue;
DebugLoc DL = PN->getDebugLoc();
unsigned PHIReg = ValueMap[PN];
assert(PHIReg && "PHI node does not have an assigned virtual register!");
SmallVector<EVT, 4> ValueVTs;
ComputeValueVTs(*TLI, MF->getDataLayout(), PN->getType(), ValueVTs);
for (unsigned vti = 0, vte = ValueVTs.size(); vti != vte; ++vti) {
EVT VT = ValueVTs[vti];
unsigned NumRegisters = TLI->getNumRegisters(Fn->getContext(), VT);
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
for (unsigned i = 0; i != NumRegisters; ++i)
BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i);
PHIReg += NumRegisters;
}
}
}
// Mark landing pad blocks.
SmallVector<const LandingPadInst *, 4> LPads;
for (BB = Fn->begin(); BB != EB; ++BB) {
if (BB->isEHPad())
MBBMap[BB]->setIsEHPad();
const Instruction *FNP = BB->getFirstNonPHI();
if (const auto *LPI = dyn_cast<LandingPadInst>(FNP))
LPads.push_back(LPI);
}
// If this is an MSVC EH personality, we need to do a bit more work.
if (!Fn->hasPersonalityFn())
return;
EHPersonality Personality = classifyEHPersonality(Fn->getPersonalityFn());
if (!isMSVCEHPersonality(Personality))
return;
if (Personality == EHPersonality::MSVC_Win64SEH ||
Personality == EHPersonality::MSVC_X86SEH) {
addSEHHandlersForLPads(LPads);
}
WinEHFuncInfo &EHInfo = MMI.getWinEHFuncInfo(&fn);
if (Personality == EHPersonality::MSVC_CXX) {
// Calculate state numbers and then map from funclet BBs to MBBs.
const Function *WinEHParentFn = MMI.getWinEHParent(&fn);
calculateWinCXXEHStateNumbers(WinEHParentFn, EHInfo);
for (WinEHTryBlockMapEntry &TBME : EHInfo.TryBlockMap)
for (WinEHHandlerType &H : TBME.HandlerArray)
if (const auto *BB = dyn_cast<BasicBlock>(H.Handler))
H.HandlerMBB = MBBMap[BB];
}
// Copy the state numbers to LandingPadInfo for the current function, which
// could be a handler or the parent. This should happen for 32-bit SEH and
// C++ EH.
if (Personality == EHPersonality::MSVC_CXX ||
Personality == EHPersonality::MSVC_X86SEH) {
for (const LandingPadInst *LP : LPads) {
MachineBasicBlock *LPadMBB = MBBMap[LP->getParent()];
MMI.addWinEHState(LPadMBB, EHInfo.EHPadStateMap[LP]);
}
}
}