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- //===-- 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 "FunctionLoweringInfo.h"
- #include "llvm/CallingConv.h"
- #include "llvm/DerivedTypes.h"
- #include "llvm/Function.h"
- #include "llvm/Instructions.h"
- #include "llvm/IntrinsicInst.h"
- #include "llvm/LLVMContext.h"
- #include "llvm/Module.h"
- #include "llvm/CodeGen/MachineFunction.h"
- #include "llvm/CodeGen/MachineFrameInfo.h"
- #include "llvm/CodeGen/MachineInstrBuilder.h"
- #include "llvm/CodeGen/MachineModuleInfo.h"
- #include "llvm/CodeGen/MachineRegisterInfo.h"
- #include "llvm/Analysis/DebugInfo.h"
- #include "llvm/Target/TargetRegisterInfo.h"
- #include "llvm/Target/TargetData.h"
- #include "llvm/Target/TargetFrameInfo.h"
- #include "llvm/Target/TargetInstrInfo.h"
- #include "llvm/Target/TargetIntrinsicInfo.h"
- #include "llvm/Target/TargetLowering.h"
- #include "llvm/Target/TargetOptions.h"
- #include "llvm/Support/Compiler.h"
- #include "llvm/Support/Debug.h"
- #include "llvm/Support/ErrorHandling.h"
- #include "llvm/Support/MathExtras.h"
- #include "llvm/Support/raw_ostream.h"
- #include <algorithm>
- using namespace llvm;
- /// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
- /// of insertvalue or extractvalue indices that identify a member, return
- /// the linearized index of the start of the member.
- ///
- unsigned llvm::ComputeLinearIndex(const TargetLowering &TLI, const Type *Ty,
- const unsigned *Indices,
- const unsigned *IndicesEnd,
- unsigned CurIndex) {
- // Base case: We're done.
- if (Indices && Indices == IndicesEnd)
- return CurIndex;
- // Given a struct type, recursively traverse the elements.
- if (const StructType *STy = dyn_cast<StructType>(Ty)) {
- for (StructType::element_iterator EB = STy->element_begin(),
- EI = EB,
- EE = STy->element_end();
- EI != EE; ++EI) {
- if (Indices && *Indices == unsigned(EI - EB))
- return ComputeLinearIndex(TLI, *EI, Indices+1, IndicesEnd, CurIndex);
- CurIndex = ComputeLinearIndex(TLI, *EI, 0, 0, CurIndex);
- }
- return CurIndex;
- }
- // Given an array type, recursively traverse the elements.
- else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
- const Type *EltTy = ATy->getElementType();
- for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
- if (Indices && *Indices == i)
- return ComputeLinearIndex(TLI, EltTy, Indices+1, IndicesEnd, CurIndex);
- CurIndex = ComputeLinearIndex(TLI, EltTy, 0, 0, CurIndex);
- }
- return CurIndex;
- }
- // We haven't found the type we're looking for, so keep searching.
- return CurIndex + 1;
- }
- /// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
- /// EVTs that represent all the individual underlying
- /// non-aggregate types that comprise it.
- ///
- /// If Offsets is non-null, it points to a vector to be filled in
- /// with the in-memory offsets of each of the individual values.
- ///
- void llvm::ComputeValueVTs(const TargetLowering &TLI, const Type *Ty,
- SmallVectorImpl<EVT> &ValueVTs,
- SmallVectorImpl<uint64_t> *Offsets,
- uint64_t StartingOffset) {
- // Given a struct type, recursively traverse the elements.
- if (const StructType *STy = dyn_cast<StructType>(Ty)) {
- const StructLayout *SL = TLI.getTargetData()->getStructLayout(STy);
- for (StructType::element_iterator EB = STy->element_begin(),
- EI = EB,
- EE = STy->element_end();
- EI != EE; ++EI)
- ComputeValueVTs(TLI, *EI, ValueVTs, Offsets,
- StartingOffset + SL->getElementOffset(EI - EB));
- return;
- }
- // Given an array type, recursively traverse the elements.
- if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
- const Type *EltTy = ATy->getElementType();
- uint64_t EltSize = TLI.getTargetData()->getTypeAllocSize(EltTy);
- for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
- ComputeValueVTs(TLI, EltTy, ValueVTs, Offsets,
- StartingOffset + i * EltSize);
- return;
- }
- // Interpret void as zero return values.
- if (Ty->isVoidTy())
- return;
- // Base case: we can get an EVT for this LLVM IR type.
- ValueVTs.push_back(TLI.getValueType(Ty));
- if (Offsets)
- Offsets->push_back(StartingOffset);
- }
- /// 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(Instruction *I) {
- if (isa<PHINode>(I)) return true;
- BasicBlock *BB = I->getParent();
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI)
- if (cast<Instruction>(*UI)->getParent() != BB || isa<PHINode>(*UI))
- return true;
- return false;
- }
- /// isOnlyUsedInEntryBlock - If the specified argument is only used in the
- /// entry block, return true. This includes arguments used by switches, since
- /// the switch may expand into multiple basic blocks.
- static bool isOnlyUsedInEntryBlock(Argument *A, bool EnableFastISel) {
- // With FastISel active, we may be splitting blocks, so force creation
- // of virtual registers for all non-dead arguments.
- // Don't force virtual registers for byval arguments though, because
- // fast-isel can't handle those in all cases.
- if (EnableFastISel && !A->hasByValAttr())
- return A->use_empty();
- BasicBlock *Entry = A->getParent()->begin();
- for (Value::use_iterator UI = A->use_begin(), E = A->use_end(); UI != E; ++UI)
- if (cast<Instruction>(*UI)->getParent() != Entry || isa<SwitchInst>(*UI))
- return false; // Use not in entry block.
- return true;
- }
- FunctionLoweringInfo::FunctionLoweringInfo(TargetLowering &tli)
- : TLI(tli) {
- }
- void FunctionLoweringInfo::set(Function &fn, MachineFunction &mf,
- bool EnableFastISel) {
- Fn = &fn;
- MF = &mf;
- RegInfo = &MF->getRegInfo();
- // Create a vreg for each argument register that is not dead and is used
- // outside of the entry block for the function.
- for (Function::arg_iterator AI = Fn->arg_begin(), E = Fn->arg_end();
- AI != E; ++AI)
- if (!isOnlyUsedInEntryBlock(AI, EnableFastISel))
- InitializeRegForValue(AI);
- // 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::iterator BB = Fn->begin(), EB = Fn->end();
- for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
- if (ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
- const Type *Ty = AI->getAllocatedType();
- uint64_t TySize = TLI.getTargetData()->getTypeAllocSize(Ty);
- unsigned Align =
- std::max((unsigned)TLI.getTargetData()->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);
- }
- for (; BB != EB; ++BB)
- for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
- if (!I->use_empty() && isUsedOutsideOfDefiningBlock(I))
- if (!isa<AllocaInst>(I) ||
- !StaticAllocaMap.count(cast<AllocaInst>(I)))
- InitializeRegForValue(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(), EB = Fn->end(); 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.
- PHINode *PN;
- DebugLoc DL;
- for (BasicBlock::iterator
- I = BB->begin(), E = BB->end(); I != E; ++I) {
- PN = dyn_cast<PHINode>(I);
- if (!PN || PN->use_empty()) continue;
- 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;
- }
- }
- }
- }
- /// 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() {
- MBBMap.clear();
- ValueMap.clear();
- StaticAllocaMap.clear();
- #ifndef NDEBUG
- CatchInfoLost.clear();
- CatchInfoFound.clear();
- #endif
- LiveOutRegInfo.clear();
- }
- unsigned FunctionLoweringInfo::MakeReg(EVT VT) {
- return RegInfo->createVirtualRegister(TLI.getRegClassFor(VT));
- }
- /// CreateRegForValue - 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::CreateRegForValue(const Value *V) {
- SmallVector<EVT, 4> ValueVTs;
- ComputeValueVTs(TLI, V->getType(), ValueVTs);
- unsigned FirstReg = 0;
- for (unsigned Value = 0, e = ValueVTs.size(); Value != e; ++Value) {
- EVT ValueVT = ValueVTs[Value];
- EVT RegisterVT = TLI.getRegisterType(V->getContext(), ValueVT);
- unsigned NumRegs = TLI.getNumRegisters(V->getContext(), ValueVT);
- for (unsigned i = 0; i != NumRegs; ++i) {
- unsigned R = MakeReg(RegisterVT);
- if (!FirstReg) FirstReg = R;
- }
- }
- return FirstReg;
- }
- /// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
- GlobalVariable *llvm::ExtractTypeInfo(Value *V) {
- V = V->stripPointerCasts();
- GlobalVariable *GV = dyn_cast<GlobalVariable>(V);
- assert ((GV || isa<ConstantPointerNull>(V)) &&
- "TypeInfo must be a global variable or NULL");
- return GV;
- }
- /// AddCatchInfo - Extract the personality and type infos from an eh.selector
- /// call, and add them to the specified machine basic block.
- void llvm::AddCatchInfo(CallInst &I, MachineModuleInfo *MMI,
- MachineBasicBlock *MBB) {
- // Inform the MachineModuleInfo of the personality for this landing pad.
- ConstantExpr *CE = cast<ConstantExpr>(I.getOperand(2));
- 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<GlobalVariable *> TyInfo;
- unsigned N = I.getNumOperands();
- for (unsigned i = N - 1; i > 2; --i) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(I.getOperand(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.getOperand(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.getOperand(j)));
- MMI->addFilterTypeInfo(MBB, TyInfo);
- TyInfo.clear();
- }
- N = i;
- }
- }
- if (N > 3) {
- TyInfo.reserve(N - 3);
- for (unsigned j = 3; j < N; ++j)
- TyInfo.push_back(ExtractTypeInfo(I.getOperand(j)));
- MMI->addCatchTypeInfo(MBB, TyInfo);
- }
- }
- void llvm::CopyCatchInfo(BasicBlock *SrcBB, BasicBlock *DestBB,
- MachineModuleInfo *MMI, FunctionLoweringInfo &FLI) {
- for (BasicBlock::iterator I = SrcBB->begin(), E = --SrcBB->end(); I != E; ++I)
- if (EHSelectorInst *EHSel = dyn_cast<EHSelectorInst>(I)) {
- // Apply the catch info to DestBB.
- AddCatchInfo(*EHSel, MMI, FLI.MBBMap[DestBB]);
- #ifndef NDEBUG
- if (!FLI.MBBMap[SrcBB]->isLandingPad())
- FLI.CatchInfoFound.insert(EHSel);
- #endif
- }
- }
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