| //===-- 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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "function-lowering-info" |
| #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/DebugInfo.h" |
| #include "llvm/IR/DataLayout.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/Target/TargetInstrInfo.h" |
| #include "llvm/Target/TargetLowering.h" |
| #include "llvm/Target/TargetOptions.h" |
| #include "llvm/Target/TargetRegisterInfo.h" |
| #include <algorithm> |
| using namespace llvm; |
| |
| /// 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 (Value::const_use_iterator UI = I->use_begin(), E = I->use_end(); |
| UI != E; ++UI) { |
| const User *U = *UI; |
| if (cast<Instruction>(U)->getParent() != BB || isa<PHINode>(U)) |
| return true; |
| } |
| return false; |
| } |
| |
| FunctionLoweringInfo::FunctionLoweringInfo(const TargetLowering &tli) |
| : TLI(tli) { |
| } |
| |
| void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf) { |
| Fn = &fn; |
| MF = &mf; |
| RegInfo = &MF->getRegInfo(); |
| |
| // 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 (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) |
| if (const AllocaInst *AI = dyn_cast<AllocaInst>(I)) |
| if (const ConstantInt *CUI = dyn_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. |
| |
| // The object may need to be placed onto the stack near the stack |
| // protector if one exists. Determine here if this object is a suitable |
| // candidate. I.e., it would trigger the creation of a stack protector. |
| bool MayNeedSP = |
| (AI->isArrayAllocation() || |
| (TySize >= 8 && isa<ArrayType>(Ty) && |
| cast<ArrayType>(Ty)->getElementType()->isIntegerTy(8))); |
| StaticAllocaMap[AI] = |
| MF->getFrameInfo()->CreateStackObject(TySize, Align, false, |
| MayNeedSP, AI); |
| } |
| |
| for (; BB != EB; ++BB) |
| for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); |
| I != E; ++I) { |
| // 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)) { |
| MachineModuleInfo &MMI = MF->getMMI(); |
| if (MMI.hasDebugInfo() && |
| DIVariable(DI->getVariable()).Verify() && |
| !DI->getDebugLoc().isUnknown()) { |
| // 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(), |
| FI, DI->getDebugLoc()); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| // 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->getTarget().getInstrInfo(); |
| for (unsigned i = 0; i != NumRegisters; ++i) |
| BuildMI(MBB, DL, TII->get(TargetOpcode::PHI), PHIReg + i); |
| PHIReg += NumRegisters; |
| } |
| } |
| } |
| |
| // Mark landing pad blocks. |
| for (BB = Fn->begin(); BB != EB; ++BB) |
| if (const InvokeInst *Invoke = dyn_cast<InvokeInst>(BB->getTerminator())) |
| MBBMap[Invoke->getSuccessor(1)]->setIsLandingPad(); |
| } |
| |
| /// 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(); |
| } |
| |
| /// CreateReg - Allocate a single virtual register for the given type. |
| unsigned FunctionLoweringInfo::CreateReg(MVT VT) { |
| return RegInfo->createVirtualRegister(TLI.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) { |
| 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 NULL; |
| |
| LiveOutInfo *LOI = &LiveOutRegInfo[Reg]; |
| if (!LOI->IsValid) |
| return NULL; |
| |
| 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 (po_iterator<Type*> i = po_begin(T), e = po_end(T); |
| i != e; ++i) { |
| if (i->isFloatingPointTy()) { |
| MMI->setUsesVAFloatArgument(true); |
| return; |
| } |
| } |
| } |
| } |
| } |
| |
| /// AddCatchInfo - Extract the personality and type infos from an eh.selector |
| /// call, and add them to the specified machine basic block. |
| void llvm::AddCatchInfo(const CallInst &I, MachineModuleInfo *MMI, |
| MachineBasicBlock *MBB) { |
| // Inform the MachineModuleInfo of the personality for this landing pad. |
| const ConstantExpr *CE = cast<ConstantExpr>(I.getArgOperand(1)); |
| assert(CE->getOpcode() == Instruction::BitCast && |
| isa<Function>(CE->getOperand(0)) && |
| "Personality should be a function"); |
| MMI->addPersonality(MBB, cast<Function>(CE->getOperand(0))); |
| |
| // Gather all the type infos for this landing pad and pass them along to |
| // MachineModuleInfo. |
| std::vector<const GlobalVariable *> TyInfo; |
| unsigned N = I.getNumArgOperands(); |
| |
| for (unsigned i = N - 1; i > 1; --i) { |
| if (const ConstantInt *CI = dyn_cast<ConstantInt>(I.getArgOperand(i))) { |
| unsigned FilterLength = CI->getZExtValue(); |
| unsigned FirstCatch = i + FilterLength + !FilterLength; |
| assert(FirstCatch <= N && "Invalid filter length"); |
| |
| if (FirstCatch < N) { |
| TyInfo.reserve(N - FirstCatch); |
| for (unsigned j = FirstCatch; j < N; ++j) |
| TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j))); |
| MMI->addCatchTypeInfo(MBB, TyInfo); |
| TyInfo.clear(); |
| } |
| |
| if (!FilterLength) { |
| // Cleanup. |
| MMI->addCleanup(MBB); |
| } else { |
| // Filter. |
| TyInfo.reserve(FilterLength - 1); |
| for (unsigned j = i + 1; j < FirstCatch; ++j) |
| TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j))); |
| MMI->addFilterTypeInfo(MBB, TyInfo); |
| TyInfo.clear(); |
| } |
| |
| N = i; |
| } |
| } |
| |
| if (N > 2) { |
| TyInfo.reserve(N - 2); |
| for (unsigned j = 2; j < N; ++j) |
| TyInfo.push_back(ExtractTypeInfo(I.getArgOperand(j))); |
| MMI->addCatchTypeInfo(MBB, TyInfo); |
| } |
| } |
| |
| /// 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.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<GlobalVariable>(Val->stripPointerCasts())); |
| } else { |
| // Add filters in a list. |
| Constant *CVal = cast<Constant>(Val); |
| SmallVector<const GlobalVariable*, 4> FilterList; |
| for (User::op_iterator |
| II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) |
| FilterList.push_back(cast<GlobalVariable>((*II)->stripPointerCasts())); |
| |
| MMI.addFilterTypeInfo(MBB, FilterList); |
| } |
| } |
| } |
