| //===- MergeFunctions.cpp - Merge identical functions ---------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass looks for equivalent functions that are mergable and folds them. |
| // |
| // A hash is computed from the function, based on its type and number of |
| // basic blocks. |
| // |
| // Once all hashes are computed, we perform an expensive equality comparison |
| // on each function pair. This takes n^2/2 comparisons per bucket, so it's |
| // important that the hash function be high quality. The equality comparison |
| // iterates through each instruction in each basic block. |
| // |
| // When a match is found the functions are folded. If both functions are |
| // overridable, we move the functionality into a new internal function and |
| // leave two overridable thunks to it. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Future work: |
| // |
| // * virtual functions. |
| // |
| // Many functions have their address taken by the virtual function table for |
| // the object they belong to. However, as long as it's only used for a lookup |
| // and call, this is irrelevant, and we'd like to fold such functions. |
| // |
| // * switch from n^2 pair-wise comparisons to an n-way comparison for each |
| // bucket. |
| // |
| // * be smarter about bitcasts. |
| // |
| // In order to fold functions, we will sometimes add either bitcast instructions |
| // or bitcast constant expressions. Unfortunately, this can confound further |
| // analysis since the two functions differ where one has a bitcast and the |
| // other doesn't. We should learn to look through bitcasts. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "mergefunc" |
| #include "llvm/Transforms/IPO.h" |
| #include "llvm/ADT/DenseSet.h" |
| #include "llvm/ADT/FoldingSet.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/Constants.h" |
| #include "llvm/InlineAsm.h" |
| #include "llvm/Instructions.h" |
| #include "llvm/LLVMContext.h" |
| #include "llvm/Module.h" |
| #include "llvm/Pass.h" |
| #include "llvm/Support/CallSite.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/IRBuilder.h" |
| #include "llvm/Support/ValueHandle.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetData.h" |
| #include <vector> |
| using namespace llvm; |
| |
| STATISTIC(NumFunctionsMerged, "Number of functions merged"); |
| |
| namespace { |
| /// MergeFunctions finds functions which will generate identical machine code, |
| /// by considering all pointer types to be equivalent. Once identified, |
| /// MergeFunctions will fold them by replacing a call to one to a call to a |
| /// bitcast of the other. |
| /// |
| class MergeFunctions : public ModulePass { |
| public: |
| static char ID; |
| MergeFunctions() : ModulePass(ID) {} |
| |
| bool runOnModule(Module &M); |
| |
| private: |
| /// MergeTwoFunctions - Merge two equivalent functions. Upon completion, G |
| /// may be deleted, or may be converted into a thunk. In either case, it |
| /// should never be visited again. |
| void MergeTwoFunctions(Function *F, Function *G) const; |
| |
| /// WriteThunk - Replace G with a simple tail call to bitcast(F). Also |
| /// replace direct uses of G with bitcast(F). |
| void WriteThunk(Function *F, Function *G) const; |
| |
| TargetData *TD; |
| }; |
| } |
| |
| char MergeFunctions::ID = 0; |
| INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false); |
| |
| ModulePass *llvm::createMergeFunctionsPass() { |
| return new MergeFunctions(); |
| } |
| |
| namespace { |
| /// FunctionComparator - Compares two functions to determine whether or not |
| /// they will generate machine code with the same behaviour. TargetData is |
| /// used if available. The comparator always fails conservatively (erring on the |
| /// side of claiming that two functions are different). |
| class FunctionComparator { |
| public: |
| FunctionComparator(const TargetData *TD, const Function *F1, |
| const Function *F2) |
| : F1(F1), F2(F2), TD(TD), IDMap1Count(0), IDMap2Count(0) {} |
| |
| /// Compare - test whether the two functions have equivalent behaviour. |
| bool Compare(); |
| |
| private: |
| /// Compare - test whether two basic blocks have equivalent behaviour. |
| bool Compare(const BasicBlock *BB1, const BasicBlock *BB2); |
| |
| /// Enumerate - Assign or look up previously assigned numbers for the two |
| /// values, and return whether the numbers are equal. Numbers are assigned in |
| /// the order visited. |
| bool Enumerate(const Value *V1, const Value *V2); |
| |
| /// isEquivalentOperation - Compare two Instructions for equivalence, similar |
| /// to Instruction::isSameOperationAs but with modifications to the type |
| /// comparison. |
| bool isEquivalentOperation(const Instruction *I1, |
| const Instruction *I2) const; |
| |
| /// isEquivalentGEP - Compare two GEPs for equivalent pointer arithmetic. |
| bool isEquivalentGEP(const GEPOperator *GEP1, const GEPOperator *GEP2); |
| bool isEquivalentGEP(const GetElementPtrInst *GEP1, |
| const GetElementPtrInst *GEP2) { |
| return isEquivalentGEP(cast<GEPOperator>(GEP1), cast<GEPOperator>(GEP2)); |
| } |
| |
| /// isEquivalentType - Compare two Types, treating all pointer types as equal. |
| bool isEquivalentType(const Type *Ty1, const Type *Ty2) const; |
| |
| // The two functions undergoing comparison. |
| const Function *F1, *F2; |
| |
| const TargetData *TD; |
| |
| typedef DenseMap<const Value *, unsigned long> IDMap; |
| IDMap Map1, Map2; |
| unsigned long IDMap1Count, IDMap2Count; |
| }; |
| } |
| |
| /// isEquivalentType - any two pointers in the same address space are |
| /// equivalent. Otherwise, standard type equivalence rules apply. |
| bool FunctionComparator::isEquivalentType(const Type *Ty1, |
| const Type *Ty2) const { |
| if (Ty1 == Ty2) |
| return true; |
| if (Ty1->getTypeID() != Ty2->getTypeID()) |
| return false; |
| |
| switch(Ty1->getTypeID()) { |
| default: |
| llvm_unreachable("Unknown type!"); |
| // Fall through in Release mode. |
| case Type::IntegerTyID: |
| case Type::OpaqueTyID: |
| // Ty1 == Ty2 would have returned true earlier. |
| return false; |
| |
| case Type::VoidTyID: |
| case Type::FloatTyID: |
| case Type::DoubleTyID: |
| case Type::X86_FP80TyID: |
| case Type::FP128TyID: |
| case Type::PPC_FP128TyID: |
| case Type::LabelTyID: |
| case Type::MetadataTyID: |
| return true; |
| |
| case Type::PointerTyID: { |
| const PointerType *PTy1 = cast<PointerType>(Ty1); |
| const PointerType *PTy2 = cast<PointerType>(Ty2); |
| return PTy1->getAddressSpace() == PTy2->getAddressSpace(); |
| } |
| |
| case Type::StructTyID: { |
| const StructType *STy1 = cast<StructType>(Ty1); |
| const StructType *STy2 = cast<StructType>(Ty2); |
| if (STy1->getNumElements() != STy2->getNumElements()) |
| return false; |
| |
| if (STy1->isPacked() != STy2->isPacked()) |
| return false; |
| |
| for (unsigned i = 0, e = STy1->getNumElements(); i != e; ++i) { |
| if (!isEquivalentType(STy1->getElementType(i), STy2->getElementType(i))) |
| return false; |
| } |
| return true; |
| } |
| |
| case Type::FunctionTyID: { |
| const FunctionType *FTy1 = cast<FunctionType>(Ty1); |
| const FunctionType *FTy2 = cast<FunctionType>(Ty2); |
| if (FTy1->getNumParams() != FTy2->getNumParams() || |
| FTy1->isVarArg() != FTy2->isVarArg()) |
| return false; |
| |
| if (!isEquivalentType(FTy1->getReturnType(), FTy2->getReturnType())) |
| return false; |
| |
| for (unsigned i = 0, e = FTy1->getNumParams(); i != e; ++i) { |
| if (!isEquivalentType(FTy1->getParamType(i), FTy2->getParamType(i))) |
| return false; |
| } |
| return true; |
| } |
| |
| case Type::ArrayTyID: { |
| const ArrayType *ATy1 = cast<ArrayType>(Ty1); |
| const ArrayType *ATy2 = cast<ArrayType>(Ty2); |
| return ATy1->getNumElements() == ATy2->getNumElements() && |
| isEquivalentType(ATy1->getElementType(), ATy2->getElementType()); |
| } |
| |
| case Type::VectorTyID: { |
| const VectorType *VTy1 = cast<VectorType>(Ty1); |
| const VectorType *VTy2 = cast<VectorType>(Ty2); |
| return VTy1->getNumElements() == VTy2->getNumElements() && |
| isEquivalentType(VTy1->getElementType(), VTy2->getElementType()); |
| } |
| } |
| } |
| |
| /// isEquivalentOperation - determine whether the two operations are the same |
| /// except that pointer-to-A and pointer-to-B are equivalent. This should be |
| /// kept in sync with Instruction::isSameOperationAs. |
| bool FunctionComparator::isEquivalentOperation(const Instruction *I1, |
| const Instruction *I2) const { |
| if (I1->getOpcode() != I2->getOpcode() || |
| I1->getNumOperands() != I2->getNumOperands() || |
| !isEquivalentType(I1->getType(), I2->getType()) || |
| !I1->hasSameSubclassOptionalData(I2)) |
| return false; |
| |
| // We have two instructions of identical opcode and #operands. Check to see |
| // if all operands are the same type |
| for (unsigned i = 0, e = I1->getNumOperands(); i != e; ++i) |
| if (!isEquivalentType(I1->getOperand(i)->getType(), |
| I2->getOperand(i)->getType())) |
| return false; |
| |
| // Check special state that is a part of some instructions. |
| if (const LoadInst *LI = dyn_cast<LoadInst>(I1)) |
| return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() && |
| LI->getAlignment() == cast<LoadInst>(I2)->getAlignment(); |
| if (const StoreInst *SI = dyn_cast<StoreInst>(I1)) |
| return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() && |
| SI->getAlignment() == cast<StoreInst>(I2)->getAlignment(); |
| if (const CmpInst *CI = dyn_cast<CmpInst>(I1)) |
| return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate(); |
| if (const CallInst *CI = dyn_cast<CallInst>(I1)) |
| return CI->isTailCall() == cast<CallInst>(I2)->isTailCall() && |
| CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() && |
| CI->getAttributes().getRawPointer() == |
| cast<CallInst>(I2)->getAttributes().getRawPointer(); |
| if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1)) |
| return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() && |
| CI->getAttributes().getRawPointer() == |
| cast<InvokeInst>(I2)->getAttributes().getRawPointer(); |
| if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1)) { |
| if (IVI->getNumIndices() != cast<InsertValueInst>(I2)->getNumIndices()) |
| return false; |
| for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i) |
| if (IVI->idx_begin()[i] != cast<InsertValueInst>(I2)->idx_begin()[i]) |
| return false; |
| return true; |
| } |
| if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1)) { |
| if (EVI->getNumIndices() != cast<ExtractValueInst>(I2)->getNumIndices()) |
| return false; |
| for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i) |
| if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I2)->idx_begin()[i]) |
| return false; |
| return true; |
| } |
| |
| return true; |
| } |
| |
| /// isEquivalentGEP - determine whether two GEP operations perform the same |
| /// underlying arithmetic. |
| bool FunctionComparator::isEquivalentGEP(const GEPOperator *GEP1, |
| const GEPOperator *GEP2) { |
| // When we have target data, we can reduce the GEP down to the value in bytes |
| // added to the address. |
| if (TD && GEP1->hasAllConstantIndices() && GEP2->hasAllConstantIndices()) { |
| SmallVector<Value *, 8> Indices1(GEP1->idx_begin(), GEP1->idx_end()); |
| SmallVector<Value *, 8> Indices2(GEP2->idx_begin(), GEP2->idx_end()); |
| uint64_t Offset1 = TD->getIndexedOffset(GEP1->getPointerOperandType(), |
| Indices1.data(), Indices1.size()); |
| uint64_t Offset2 = TD->getIndexedOffset(GEP2->getPointerOperandType(), |
| Indices2.data(), Indices2.size()); |
| return Offset1 == Offset2; |
| } |
| |
| if (GEP1->getPointerOperand()->getType() != |
| GEP2->getPointerOperand()->getType()) |
| return false; |
| |
| if (GEP1->getNumOperands() != GEP2->getNumOperands()) |
| return false; |
| |
| for (unsigned i = 0, e = GEP1->getNumOperands(); i != e; ++i) { |
| if (!Enumerate(GEP1->getOperand(i), GEP2->getOperand(i))) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /// Enumerate - Compare two values used by the two functions under pair-wise |
| /// comparison. If this is the first time the values are seen, they're added to |
| /// the mapping so that we will detect mismatches on next use. |
| bool FunctionComparator::Enumerate(const Value *V1, const Value *V2) { |
| // Check for function @f1 referring to itself and function @f2 referring to |
| // itself, or referring to each other, or both referring to either of them. |
| // They're all equivalent if the two functions are otherwise equivalent. |
| if (V1 == F1 && V2 == F2) |
| return true; |
| if (V1 == F2 && V2 == F1) |
| return true; |
| |
| // TODO: constant expressions with GEP or references to F1 or F2. |
| if (isa<Constant>(V1)) |
| return V1 == V2; |
| |
| if (isa<InlineAsm>(V1) && isa<InlineAsm>(V2)) { |
| const InlineAsm *IA1 = cast<InlineAsm>(V1); |
| const InlineAsm *IA2 = cast<InlineAsm>(V2); |
| return IA1->getAsmString() == IA2->getAsmString() && |
| IA1->getConstraintString() == IA2->getConstraintString(); |
| } |
| |
| unsigned long &ID1 = Map1[V1]; |
| if (!ID1) |
| ID1 = ++IDMap1Count; |
| |
| unsigned long &ID2 = Map2[V2]; |
| if (!ID2) |
| ID2 = ++IDMap2Count; |
| |
| return ID1 == ID2; |
| } |
| |
| /// Compare - test whether two basic blocks have equivalent behaviour. |
| bool FunctionComparator::Compare(const BasicBlock *BB1, const BasicBlock *BB2) { |
| BasicBlock::const_iterator F1I = BB1->begin(), F1E = BB1->end(); |
| BasicBlock::const_iterator F2I = BB2->begin(), F2E = BB2->end(); |
| |
| do { |
| if (!Enumerate(F1I, F2I)) |
| return false; |
| |
| if (const GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(F1I)) { |
| const GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(F2I); |
| if (!GEP2) |
| return false; |
| |
| if (!Enumerate(GEP1->getPointerOperand(), GEP2->getPointerOperand())) |
| return false; |
| |
| if (!isEquivalentGEP(GEP1, GEP2)) |
| return false; |
| } else { |
| if (!isEquivalentOperation(F1I, F2I)) |
| return false; |
| |
| assert(F1I->getNumOperands() == F2I->getNumOperands()); |
| for (unsigned i = 0, e = F1I->getNumOperands(); i != e; ++i) { |
| Value *OpF1 = F1I->getOperand(i); |
| Value *OpF2 = F2I->getOperand(i); |
| |
| if (!Enumerate(OpF1, OpF2)) |
| return false; |
| |
| if (OpF1->getValueID() != OpF2->getValueID() || |
| !isEquivalentType(OpF1->getType(), OpF2->getType())) |
| return false; |
| } |
| } |
| |
| ++F1I, ++F2I; |
| } while (F1I != F1E && F2I != F2E); |
| |
| return F1I == F1E && F2I == F2E; |
| } |
| |
| /// Compare - test whether the two functions have equivalent behaviour. |
| bool FunctionComparator::Compare() { |
| // We need to recheck everything, but check the things that weren't included |
| // in the hash first. |
| |
| if (F1->getAttributes() != F2->getAttributes()) |
| return false; |
| |
| if (F1->hasGC() != F2->hasGC()) |
| return false; |
| |
| if (F1->hasGC() && F1->getGC() != F2->getGC()) |
| return false; |
| |
| if (F1->hasSection() != F2->hasSection()) |
| return false; |
| |
| if (F1->hasSection() && F1->getSection() != F2->getSection()) |
| return false; |
| |
| if (F1->isVarArg() != F2->isVarArg()) |
| return false; |
| |
| // TODO: if it's internal and only used in direct calls, we could handle this |
| // case too. |
| if (F1->getCallingConv() != F2->getCallingConv()) |
| return false; |
| |
| if (!isEquivalentType(F1->getFunctionType(), F2->getFunctionType())) |
| return false; |
| |
| assert(F1->arg_size() == F2->arg_size() && |
| "Identical functions have a different number of args."); |
| |
| // Visit the arguments so that they get enumerated in the order they're |
| // passed in. |
| for (Function::const_arg_iterator f1i = F1->arg_begin(), |
| f2i = F2->arg_begin(), f1e = F1->arg_end(); f1i != f1e; ++f1i, ++f2i) { |
| if (!Enumerate(f1i, f2i)) |
| llvm_unreachable("Arguments repeat"); |
| } |
| |
| // We do a CFG-ordered walk since the actual ordering of the blocks in the |
| // linked list is immaterial. Our walk starts at the entry block for both |
| // functions, then takes each block from each terminator in order. As an |
| // artifact, this also means that unreachable blocks are ignored. |
| SmallVector<const BasicBlock *, 8> F1BBs, F2BBs; |
| SmallSet<const BasicBlock *, 128> VisitedBBs; // in terms of F1. |
| |
| F1BBs.push_back(&F1->getEntryBlock()); |
| F2BBs.push_back(&F2->getEntryBlock()); |
| |
| VisitedBBs.insert(F1BBs[0]); |
| while (!F1BBs.empty()) { |
| const BasicBlock *F1BB = F1BBs.pop_back_val(); |
| const BasicBlock *F2BB = F2BBs.pop_back_val(); |
| |
| if (!Enumerate(F1BB, F2BB) || !Compare(F1BB, F2BB)) |
| return false; |
| |
| const TerminatorInst *F1TI = F1BB->getTerminator(); |
| const TerminatorInst *F2TI = F2BB->getTerminator(); |
| |
| assert(F1TI->getNumSuccessors() == F2TI->getNumSuccessors()); |
| for (unsigned i = 0, e = F1TI->getNumSuccessors(); i != e; ++i) { |
| if (!VisitedBBs.insert(F1TI->getSuccessor(i))) |
| continue; |
| |
| F1BBs.push_back(F1TI->getSuccessor(i)); |
| F2BBs.push_back(F2TI->getSuccessor(i)); |
| } |
| } |
| return true; |
| } |
| |
| /// WriteThunk - Replace G with a simple tail call to bitcast(F). Also replace |
| /// direct uses of G with bitcast(F). |
| void MergeFunctions::WriteThunk(Function *F, Function *G) const { |
| if (!G->mayBeOverridden()) { |
| // Redirect direct callers of G to F. |
| Constant *BitcastF = ConstantExpr::getBitCast(F, G->getType()); |
| for (Value::use_iterator UI = G->use_begin(), UE = G->use_end(); |
| UI != UE;) { |
| Value::use_iterator TheIter = UI; |
| ++UI; |
| CallSite CS(*TheIter); |
| if (CS && CS.isCallee(TheIter)) |
| TheIter.getUse().set(BitcastF); |
| } |
| } |
| |
| // If G was internal then we may have replaced all uses if G with F. If so, |
| // stop here and delete G. There's no need for a thunk. |
| if (G->hasLocalLinkage() && G->use_empty()) { |
| G->eraseFromParent(); |
| return; |
| } |
| |
| Function *NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "", |
| G->getParent()); |
| BasicBlock *BB = BasicBlock::Create(F->getContext(), "", NewG); |
| IRBuilder<false> Builder(BB); |
| |
| SmallVector<Value *, 16> Args; |
| unsigned i = 0; |
| const FunctionType *FFTy = F->getFunctionType(); |
| for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end(); |
| AI != AE; ++AI) { |
| Args.push_back(Builder.CreateBitCast(AI, FFTy->getParamType(i))); |
| ++i; |
| } |
| |
| CallInst *CI = Builder.CreateCall(F, Args.begin(), Args.end()); |
| CI->setTailCall(); |
| CI->setCallingConv(F->getCallingConv()); |
| if (NewG->getReturnType()->isVoidTy()) { |
| Builder.CreateRetVoid(); |
| } else { |
| Builder.CreateRet(Builder.CreateBitCast(CI, NewG->getReturnType())); |
| } |
| |
| NewG->copyAttributesFrom(G); |
| NewG->takeName(G); |
| G->replaceAllUsesWith(NewG); |
| G->eraseFromParent(); |
| } |
| |
| /// MergeTwoFunctions - Merge two equivalent functions. Upon completion, |
| /// Function G is deleted. |
| void MergeFunctions::MergeTwoFunctions(Function *F, Function *G) const { |
| if (F->isWeakForLinker()) { |
| assert(G->isWeakForLinker()); |
| |
| // Make them both thunks to the same internal function. |
| Function *H = Function::Create(F->getFunctionType(), F->getLinkage(), "", |
| F->getParent()); |
| H->copyAttributesFrom(F); |
| H->takeName(F); |
| F->replaceAllUsesWith(H); |
| |
| unsigned MaxAlignment = std::max(G->getAlignment(), H->getAlignment()); |
| |
| WriteThunk(F, G); |
| WriteThunk(F, H); |
| |
| F->setAlignment(MaxAlignment); |
| F->setLinkage(GlobalValue::InternalLinkage); |
| } else { |
| WriteThunk(F, G); |
| } |
| |
| ++NumFunctionsMerged; |
| } |
| |
| static unsigned ProfileFunction(const Function *F) { |
| const FunctionType *FTy = F->getFunctionType(); |
| |
| FoldingSetNodeID ID; |
| ID.AddInteger(F->size()); |
| ID.AddInteger(F->getCallingConv()); |
| ID.AddBoolean(F->hasGC()); |
| ID.AddBoolean(FTy->isVarArg()); |
| ID.AddInteger(FTy->getReturnType()->getTypeID()); |
| for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) |
| ID.AddInteger(FTy->getParamType(i)->getTypeID()); |
| return ID.ComputeHash(); |
| } |
| |
| class ComparableFunction { |
| public: |
| ComparableFunction(Function *Func, TargetData *TD) |
| : Func(Func), Hash(ProfileFunction(Func)), TD(TD) {} |
| |
| AssertingVH<Function> const Func; |
| const unsigned Hash; |
| TargetData * const TD; |
| }; |
| |
| struct MergeFunctionsEqualityInfo { |
| static ComparableFunction *getEmptyKey() { |
| return reinterpret_cast<ComparableFunction*>(0); |
| } |
| static ComparableFunction *getTombstoneKey() { |
| return reinterpret_cast<ComparableFunction*>(-1); |
| } |
| static unsigned getHashValue(const ComparableFunction *CF) { |
| return CF->Hash; |
| } |
| static bool isEqual(const ComparableFunction *LHS, |
| const ComparableFunction *RHS) { |
| if (LHS == RHS) |
| return true; |
| if (LHS == getEmptyKey() || LHS == getTombstoneKey() || |
| RHS == getEmptyKey() || RHS == getTombstoneKey()) |
| return false; |
| assert(LHS->TD == RHS->TD && "Comparing functions for different targets"); |
| return FunctionComparator(LHS->TD, LHS->Func, RHS->Func).Compare(); |
| } |
| }; |
| |
| bool MergeFunctions::runOnModule(Module &M) { |
| typedef DenseSet<ComparableFunction *, MergeFunctionsEqualityInfo> FnSetType; |
| |
| bool Changed = false; |
| TD = getAnalysisIfAvailable<TargetData>(); |
| |
| std::vector<Function *> Funcs; |
| for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) { |
| if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage()) |
| Funcs.push_back(F); |
| } |
| |
| bool LocalChanged; |
| do { |
| LocalChanged = false; |
| |
| FnSetType FnSet; |
| for (unsigned i = 0, e = Funcs.size(); i != e;) { |
| Function *F = Funcs[i]; |
| ComparableFunction *NewF = new ComparableFunction(F, TD); |
| std::pair<FnSetType::iterator, bool> Result = FnSet.insert(NewF); |
| if (!Result.second) { |
| ComparableFunction *&OldF = *Result.first; |
| assert(OldF && "Expected a hash collision"); |
| |
| // NewF will be deleted in favour of OldF unless NewF is strong and |
| // OldF is weak in which case swap them to keep the strong definition. |
| |
| if (OldF->Func->isWeakForLinker() && !NewF->Func->isWeakForLinker()) |
| std::swap(OldF, NewF); |
| |
| DEBUG(dbgs() << " " << OldF->Func->getName() << " == " |
| << NewF->Func->getName() << '\n'); |
| |
| Funcs.erase(Funcs.begin() + i); |
| --e; |
| |
| Function *DeleteF = NewF->Func; |
| delete NewF; |
| MergeTwoFunctions(OldF->Func, DeleteF); |
| LocalChanged = true; |
| Changed = true; |
| } else { |
| ++i; |
| } |
| } |
| DeleteContainerPointers(FnSet); |
| } while (LocalChanged); |
| |
| return Changed; |
| } |