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Diffstat (limited to 'contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp')
-rw-r--r-- | contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp | 576 |
1 files changed, 576 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp new file mode 100644 index 0000000..ecaa2c9 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp @@ -0,0 +1,576 @@ +//===-- FunctionLoweringInfo.cpp ------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This implements routines for translating functions from LLVM IR into +// Machine IR. +// +//===----------------------------------------------------------------------===// + +#include "llvm/CodeGen/FunctionLoweringInfo.h" +#include "llvm/ADT/PostOrderIterator.h" +#include "llvm/CodeGen/Analysis.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/MachineModuleInfo.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/WinEHFuncInfo.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DebugInfo.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Module.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetFrameLowering.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetOptions.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetSubtargetInfo.h" +#include <algorithm> +using namespace llvm; + +#define DEBUG_TYPE "function-lowering-info" + +/// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by +/// PHI nodes or outside of the basic block that defines it, or used by a +/// switch or atomic instruction, which may expand to multiple basic blocks. +static bool isUsedOutsideOfDefiningBlock(const Instruction *I) { + if (I->use_empty()) return false; + if (isa<PHINode>(I)) return true; + const BasicBlock *BB = I->getParent(); + for (const User *U : I->users()) + if (cast<Instruction>(U)->getParent() != BB || isa<PHINode>(U)) + return true; + + return false; +} + +static ISD::NodeType getPreferredExtendForValue(const Value *V) { + // For the users of the source value being used for compare instruction, if + // the number of signed predicate is greater than unsigned predicate, we + // prefer to use SIGN_EXTEND. + // + // With this optimization, we would be able to reduce some redundant sign or + // zero extension instruction, and eventually more machine CSE opportunities + // can be exposed. + ISD::NodeType ExtendKind = ISD::ANY_EXTEND; + unsigned NumOfSigned = 0, NumOfUnsigned = 0; + for (const User *U : V->users()) { + if (const auto *CI = dyn_cast<CmpInst>(U)) { + NumOfSigned += CI->isSigned(); + NumOfUnsigned += CI->isUnsigned(); + } + } + if (NumOfSigned > NumOfUnsigned) + ExtendKind = ISD::SIGN_EXTEND; + + return ExtendKind; +} + +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); + 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 = TLI->getDataLayout()->getTypeAllocSize(Ty); + unsigned Align = + std::max((unsigned)TLI->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)TLI->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(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()->setHasInlineAsmWithSPAdjust(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, 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 (const auto *Invoke = dyn_cast<InvokeInst>(BB->getTerminator())) + MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad(); + if (BB->isLandingPad()) + LPads.push_back(BB->getLandingPadInst()); + } + + // If this is an MSVC EH personality, we need to do a bit more work. + EHPersonality Personality = EHPersonality::Unknown; + if (Fn->hasPersonalityFn()) + 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) { + const Function *WinEHParentFn = MMI.getWinEHParent(&fn); + calculateWinCXXEHStateNumbers(WinEHParentFn, EHInfo); + } + + // 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.LandingPadStateMap[LP]); + } + } +} + +void FunctionLoweringInfo::addSEHHandlersForLPads( + ArrayRef<const LandingPadInst *> LPads) { + MachineModuleInfo &MMI = MF->getMMI(); + + // Iterate over all landing pads with llvm.eh.actions calls. + for (const LandingPadInst *LP : LPads) { + const IntrinsicInst *ActionsCall = + dyn_cast<IntrinsicInst>(LP->getNextNode()); + if (!ActionsCall || + ActionsCall->getIntrinsicID() != Intrinsic::eh_actions) + continue; + + // Parse the llvm.eh.actions call we found. + MachineBasicBlock *LPadMBB = MBBMap[LP->getParent()]; + SmallVector<std::unique_ptr<ActionHandler>, 4> Actions; + parseEHActions(ActionsCall, Actions); + + // Iterate EH actions from most to least precedence, which means + // iterating in reverse. + for (auto I = Actions.rbegin(), E = Actions.rend(); I != E; ++I) { + ActionHandler *Action = I->get(); + if (auto *CH = dyn_cast<CatchHandler>(Action)) { + const auto *Filter = + dyn_cast<Function>(CH->getSelector()->stripPointerCasts()); + assert((Filter || CH->getSelector()->isNullValue()) && + "expected function or catch-all"); + const auto *RecoverBA = + cast<BlockAddress>(CH->getHandlerBlockOrFunc()); + MMI.addSEHCatchHandler(LPadMBB, Filter, RecoverBA); + } else { + assert(isa<CleanupHandler>(Action)); + const auto *Fini = cast<Function>(Action->getHandlerBlockOrFunc()); + MMI.addSEHCleanupHandler(LPadMBB, Fini); + } + } + } +} + +/// clear - Clear out all the function-specific state. This returns this +/// FunctionLoweringInfo to an empty state, ready to be used for a +/// different function. +void FunctionLoweringInfo::clear() { + assert(CatchInfoFound.size() == CatchInfoLost.size() && + "Not all catch info was assigned to a landing pad!"); + + MBBMap.clear(); + ValueMap.clear(); + StaticAllocaMap.clear(); +#ifndef NDEBUG + CatchInfoLost.clear(); + CatchInfoFound.clear(); +#endif + LiveOutRegInfo.clear(); + VisitedBBs.clear(); + ArgDbgValues.clear(); + ByValArgFrameIndexMap.clear(); + RegFixups.clear(); + StatepointStackSlots.clear(); + StatepointRelocatedValues.clear(); + PreferredExtendType.clear(); +} + +/// CreateReg - Allocate a single virtual register for the given type. +unsigned FunctionLoweringInfo::CreateReg(MVT VT) { + return RegInfo->createVirtualRegister( + MF->getSubtarget().getTargetLowering()->getRegClassFor(VT)); +} + +/// CreateRegs - Allocate the appropriate number of virtual registers of +/// the correctly promoted or expanded types. Assign these registers +/// consecutive vreg numbers and return the first assigned number. +/// +/// In the case that the given value has struct or array type, this function +/// will assign registers for each member or element. +/// +unsigned FunctionLoweringInfo::CreateRegs(Type *Ty) { + const TargetLowering *TLI = MF->getSubtarget().getTargetLowering(); + + SmallVector<EVT, 4> ValueVTs; + ComputeValueVTs(*TLI, Ty, ValueVTs); + + unsigned FirstReg = 0; + for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) { + EVT ValueVT = ValueVTs[Value]; + MVT RegisterVT = TLI->getRegisterType(Ty->getContext(), ValueVT); + + unsigned NumRegs = TLI->getNumRegisters(Ty->getContext(), ValueVT); + for (unsigned i = 0; i != NumRegs; ++i) { + unsigned R = CreateReg(RegisterVT); + if (!FirstReg) FirstReg = R; + } + } + return FirstReg; +} + +/// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the +/// register is a PHI destination and the PHI's LiveOutInfo is not valid. If +/// the register's LiveOutInfo is for a smaller bit width, it is extended to +/// the larger bit width by zero extension. The bit width must be no smaller +/// than the LiveOutInfo's existing bit width. +const FunctionLoweringInfo::LiveOutInfo * +FunctionLoweringInfo::GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth) { + if (!LiveOutRegInfo.inBounds(Reg)) + return nullptr; + + LiveOutInfo *LOI = &LiveOutRegInfo[Reg]; + if (!LOI->IsValid) + return nullptr; + + if (BitWidth > LOI->KnownZero.getBitWidth()) { + LOI->NumSignBits = 1; + LOI->KnownZero = LOI->KnownZero.zextOrTrunc(BitWidth); + LOI->KnownOne = LOI->KnownOne.zextOrTrunc(BitWidth); + } + + return LOI; +} + +/// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination +/// register based on the LiveOutInfo of its operands. +void FunctionLoweringInfo::ComputePHILiveOutRegInfo(const PHINode *PN) { + Type *Ty = PN->getType(); + if (!Ty->isIntegerTy() || Ty->isVectorTy()) + return; + + SmallVector<EVT, 1> ValueVTs; + ComputeValueVTs(*TLI, Ty, ValueVTs); + assert(ValueVTs.size() == 1 && + "PHIs with non-vector integer types should have a single VT."); + EVT IntVT = ValueVTs[0]; + + if (TLI->getNumRegisters(PN->getContext(), IntVT) != 1) + return; + IntVT = TLI->getTypeToTransformTo(PN->getContext(), IntVT); + unsigned BitWidth = IntVT.getSizeInBits(); + + unsigned DestReg = ValueMap[PN]; + if (!TargetRegisterInfo::isVirtualRegister(DestReg)) + return; + LiveOutRegInfo.grow(DestReg); + LiveOutInfo &DestLOI = LiveOutRegInfo[DestReg]; + + Value *V = PN->getIncomingValue(0); + if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) { + DestLOI.NumSignBits = 1; + APInt Zero(BitWidth, 0); + DestLOI.KnownZero = Zero; + DestLOI.KnownOne = Zero; + return; + } + + if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { + APInt Val = CI->getValue().zextOrTrunc(BitWidth); + DestLOI.NumSignBits = Val.getNumSignBits(); + DestLOI.KnownZero = ~Val; + DestLOI.KnownOne = Val; + } else { + assert(ValueMap.count(V) && "V should have been placed in ValueMap when its" + "CopyToReg node was created."); + unsigned SrcReg = ValueMap[V]; + if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) { + DestLOI.IsValid = false; + return; + } + const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth); + if (!SrcLOI) { + DestLOI.IsValid = false; + return; + } + DestLOI = *SrcLOI; + } + + assert(DestLOI.KnownZero.getBitWidth() == BitWidth && + DestLOI.KnownOne.getBitWidth() == BitWidth && + "Masks should have the same bit width as the type."); + + for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) { + Value *V = PN->getIncomingValue(i); + if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) { + DestLOI.NumSignBits = 1; + APInt Zero(BitWidth, 0); + DestLOI.KnownZero = Zero; + DestLOI.KnownOne = Zero; + return; + } + + if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { + APInt Val = CI->getValue().zextOrTrunc(BitWidth); + DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, Val.getNumSignBits()); + DestLOI.KnownZero &= ~Val; + DestLOI.KnownOne &= Val; + continue; + } + + assert(ValueMap.count(V) && "V should have been placed in ValueMap when " + "its CopyToReg node was created."); + unsigned SrcReg = ValueMap[V]; + if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) { + DestLOI.IsValid = false; + return; + } + const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth); + if (!SrcLOI) { + DestLOI.IsValid = false; + return; + } + DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, SrcLOI->NumSignBits); + DestLOI.KnownZero &= SrcLOI->KnownZero; + DestLOI.KnownOne &= SrcLOI->KnownOne; + } +} + +/// setArgumentFrameIndex - Record frame index for the byval +/// argument. This overrides previous frame index entry for this argument, +/// if any. +void FunctionLoweringInfo::setArgumentFrameIndex(const Argument *A, + int FI) { + ByValArgFrameIndexMap[A] = FI; +} + +/// getArgumentFrameIndex - Get frame index for the byval argument. +/// If the argument does not have any assigned frame index then 0 is +/// returned. +int FunctionLoweringInfo::getArgumentFrameIndex(const Argument *A) { + DenseMap<const Argument *, int>::iterator I = + ByValArgFrameIndexMap.find(A); + if (I != ByValArgFrameIndexMap.end()) + return I->second; + DEBUG(dbgs() << "Argument does not have assigned frame index!\n"); + return 0; +} + +/// ComputeUsesVAFloatArgument - Determine if any floating-point values are +/// being passed to this variadic function, and set the MachineModuleInfo's +/// usesVAFloatArgument flag if so. This flag is used to emit an undefined +/// reference to _fltused on Windows, which will link in MSVCRT's +/// floating-point support. +void llvm::ComputeUsesVAFloatArgument(const CallInst &I, + MachineModuleInfo *MMI) +{ + FunctionType *FT = cast<FunctionType>( + I.getCalledValue()->getType()->getContainedType(0)); + if (FT->isVarArg() && !MMI->usesVAFloatArgument()) { + for (unsigned i = 0, e = I.getNumArgOperands(); i != e; ++i) { + Type* T = I.getArgOperand(i)->getType(); + for (auto i : post_order(T)) { + if (i->isFloatingPointTy()) { + MMI->setUsesVAFloatArgument(true); + return; + } + } + } + } +} + +/// AddLandingPadInfo - Extract the exception handling information from the +/// landingpad instruction and add them to the specified machine module info. +void llvm::AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI, + MachineBasicBlock *MBB) { + MMI.addPersonality( + MBB, + cast<Function>( + I.getParent()->getParent()->getPersonalityFn()->stripPointerCasts())); + + if (I.isCleanup()) + MMI.addCleanup(MBB); + + // FIXME: New EH - Add the clauses in reverse order. This isn't 100% correct, + // but we need to do it this way because of how the DWARF EH emitter + // processes the clauses. + for (unsigned i = I.getNumClauses(); i != 0; --i) { + Value *Val = I.getClause(i - 1); + if (I.isCatch(i - 1)) { + MMI.addCatchTypeInfo(MBB, + dyn_cast<GlobalValue>(Val->stripPointerCasts())); + } else { + // Add filters in a list. + Constant *CVal = cast<Constant>(Val); + SmallVector<const GlobalValue*, 4> FilterList; + for (User::op_iterator + II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) + FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts())); + + MMI.addFilterTypeInfo(MBB, FilterList); + } + } +} |