X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FTransforms%2FUtils%2FCloneFunction.cpp;h=995d6e4baa754a38a3d07a16b7eaee5d82c4b986;hp=ca22003b4094eca3158faba5ac4287d3865895e8;hb=da92e119096b6e2e93efbf44ed07ea0a715cef9c;hpb=51cbcbf435d1aaa1a5269d62b5d0b31b57316b4a diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp index ca22003b409..6454afb8bc4 100644 --- a/lib/Transforms/Utils/CloneFunction.cpp +++ b/lib/Transforms/Utils/CloneFunction.cpp @@ -1,5 +1,12 @@ //===- CloneFunction.cpp - Clone a function into another function ---------===// // +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// // This file implements the CloneFunctionInto interface, which is used as the // low-level function cloner. This is used by the CloneFunction and function // inliner to do the dirty work of copying the body of a function around. @@ -7,45 +14,111 @@ //===----------------------------------------------------------------------===// #include "llvm/Transforms/Utils/Cloning.h" -#include "llvm/iTerminators.h" -#include "llvm/DerivedTypes.h" -#include "llvm/Function.h" -#include "ValueMapper.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/InstructionSimplify.h" +#include "llvm/Analysis/LoopInfo.h" +#include "llvm/IR/CFG.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DebugInfo.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/GlobalVariable.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Metadata.h" +#include "llvm/IR/Module.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Transforms/Utils/Local.h" +#include "llvm/Transforms/Utils/ValueMapper.h" +#include +using namespace llvm; -// RemapInstruction - Convert the instruction operands from referencing the -// current values into those specified by ValueMap. -// -static inline void RemapInstruction(Instruction *I, - std::map &ValueMap) { - for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) { - const Value *Op = I->getOperand(op); - Value *V = MapValue(Op, ValueMap); -#ifndef NDEBUG - if (!V) { - std::cerr << "Val = \n" << Op << "Addr = " << (void*)Op; - std::cerr << "\nInst = " << I; +/// See comments in Cloning.h. +BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, + ValueToValueMapTy &VMap, + const Twine &NameSuffix, Function *F, + ClonedCodeInfo *CodeInfo) { + BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F); + if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix); + + bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false; + + // Loop over all instructions, and copy them over. + for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end(); + II != IE; ++II) { + Instruction *NewInst = II->clone(); + if (II->hasName()) + NewInst->setName(II->getName()+NameSuffix); + NewBB->getInstList().push_back(NewInst); + VMap[&*II] = NewInst; // Add instruction map to value. + + hasCalls |= (isa(II) && !isa(II)); + if (const AllocaInst *AI = dyn_cast(II)) { + if (isa(AI->getArraySize())) + hasStaticAllocas = true; + else + hasDynamicAllocas = true; } -#endif - assert(V && "Referenced value not in value map!"); - I->setOperand(op, V); } + + if (CodeInfo) { + CodeInfo->ContainsCalls |= hasCalls; + CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas; + CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas && + BB != &BB->getParent()->getEntryBlock(); + } + return NewBB; } // Clone OldFunc into NewFunc, transforming the old arguments into references to -// ArgMap values. +// VMap values. // -void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, - std::map &ValueMap, - std::vector &Returns, - const char *NameSuffix) { +void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc, + ValueToValueMapTy &VMap, + bool ModuleLevelChanges, + SmallVectorImpl &Returns, + const char *NameSuffix, ClonedCodeInfo *CodeInfo, + ValueMapTypeRemapper *TypeMapper, + ValueMaterializer *Materializer) { assert(NameSuffix && "NameSuffix cannot be null!"); - + #ifndef NDEBUG - for (Function::const_aiterator I = OldFunc->abegin(), E = OldFunc->aend(); - I != E; ++I) - assert(ValueMap.count(I) && "No mapping from source argument specified!"); + for (const Argument &I : OldFunc->args()) + assert(VMap.count(&I) && "No mapping from source argument specified!"); #endif + // Copy all attributes other than those stored in the AttributeSet. We need + // to remap the parameter indices of the AttributeSet. + AttributeSet NewAttrs = NewFunc->getAttributes(); + NewFunc->copyAttributesFrom(OldFunc); + NewFunc->setAttributes(NewAttrs); + + // Fix up the personality function that got copied over. + if (OldFunc->hasPersonalityFn()) + NewFunc->setPersonalityFn( + MapValue(OldFunc->getPersonalityFn(), VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges, + TypeMapper, Materializer)); + + AttributeSet OldAttrs = OldFunc->getAttributes(); + // Clone any argument attributes that are present in the VMap. + for (const Argument &OldArg : OldFunc->args()) + if (Argument *NewArg = dyn_cast(VMap[&OldArg])) { + AttributeSet attrs = + OldAttrs.getParamAttributes(OldArg.getArgNo() + 1); + if (attrs.getNumSlots() > 0) + NewArg->addAttr(attrs); + } + + NewFunc->setAttributes( + NewFunc->getAttributes() + .addAttributes(NewFunc->getContext(), AttributeSet::ReturnIndex, + OldAttrs.getRetAttributes()) + .addAttributes(NewFunc->getContext(), AttributeSet::FunctionIndex, + OldAttrs.getFnAttributes())); + // Loop over all of the basic blocks in the function, cloning them as // appropriate. Note that we save BE this way in order to handle cloning of // recursive functions into themselves. @@ -53,74 +126,619 @@ void CloneFunctionInto(Function *NewFunc, const Function *OldFunc, for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end(); BI != BE; ++BI) { const BasicBlock &BB = *BI; - - // Create a new basic block to copy instructions into! - BasicBlock *CBB = new BasicBlock("", NewFunc); - if (BB.hasName()) CBB->setName(BB.getName()+NameSuffix); - ValueMap[&BB] = CBB; // Add basic block mapping. - // Loop over all instructions copying them over... - for (BasicBlock::const_iterator II = BB.begin(), IE = BB.end(); - II != IE; ++II) { - Instruction *NewInst = II->clone(); - if (II->hasName()) - NewInst->setName(II->getName()+NameSuffix); // Name is not cloned... - CBB->getInstList().push_back(NewInst); - ValueMap[II] = NewInst; // Add instruction map to value. + // Create a new basic block and copy instructions into it! + BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo); + + // Add basic block mapping. + VMap[&BB] = CBB; + + // It is only legal to clone a function if a block address within that + // function is never referenced outside of the function. Given that, we + // want to map block addresses from the old function to block addresses in + // the clone. (This is different from the generic ValueMapper + // implementation, which generates an invalid blockaddress when + // cloning a function.) + if (BB.hasAddressTaken()) { + Constant *OldBBAddr = BlockAddress::get(const_cast(OldFunc), + const_cast(&BB)); + VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB); } + // Note return instructions for the caller. if (ReturnInst *RI = dyn_cast(CBB->getTerminator())) Returns.push_back(RI); } - // Loop over all of the instructions in the function, fixing up operand - // references as we go. This uses ValueMap to do all the hard work. - // - for (Function::const_iterator BB = OldFunc->begin(), BE = OldFunc->end(); - BB != BE; ++BB) { - BasicBlock *NBB = cast(ValueMap[BB]); - + // Loop over all of the instructions in the function, fixing up operand + // references as we go. This uses VMap to do all the hard work. + for (Function::iterator BB = + cast(VMap[&OldFunc->front()])->getIterator(), + BE = NewFunc->end(); + BB != BE; ++BB) // Loop over all instructions, fixing each one as we find it... - for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); ++II) - RemapInstruction(II, ValueMap); + for (Instruction &II : *BB) + RemapInstruction(&II, VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges, + TypeMapper, Materializer); +} + +// Find the MDNode which corresponds to the subprogram data that described F. +static DISubprogram *FindSubprogram(const Function *F, + DebugInfoFinder &Finder) { + for (DISubprogram *Subprogram : Finder.subprograms()) { + if (Subprogram->describes(F)) + return Subprogram; } + return nullptr; } -/// CloneFunction - Return a copy of the specified function, but without +// Add an operand to an existing MDNode. The new operand will be added at the +// back of the operand list. +static void AddOperand(DICompileUnit *CU, DISubprogramArray SPs, + Metadata *NewSP) { + SmallVector NewSPs; + NewSPs.reserve(SPs.size() + 1); + for (auto *SP : SPs) + NewSPs.push_back(SP); + NewSPs.push_back(NewSP); + CU->replaceSubprograms(MDTuple::get(CU->getContext(), NewSPs)); +} + +// Clone the module-level debug info associated with OldFunc. The cloned data +// will point to NewFunc instead. +static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc, + ValueToValueMapTy &VMap) { + DebugInfoFinder Finder; + Finder.processModule(*OldFunc->getParent()); + + const DISubprogram *OldSubprogramMDNode = FindSubprogram(OldFunc, Finder); + if (!OldSubprogramMDNode) return; + + auto *NewSubprogram = + cast(MapMetadata(OldSubprogramMDNode, VMap)); + NewFunc->setSubprogram(NewSubprogram); + + for (auto *CU : Finder.compile_units()) { + auto Subprograms = CU->getSubprograms(); + // If the compile unit's function list contains the old function, it should + // also contain the new one. + for (auto *SP : Subprograms) { + if (SP == OldSubprogramMDNode) { + AddOperand(CU, Subprograms, NewSubprogram); + break; + } + } + } +} + +/// Return a copy of the specified function, but without /// embedding the function into another module. Also, any references specified -/// in the ValueMap are changed to refer to their mapped value instead of the -/// original one. If any of the arguments to the function are in the ValueMap, -/// the arguments are deleted from the resultant function. The ValueMap is +/// in the VMap are changed to refer to their mapped value instead of the +/// original one. If any of the arguments to the function are in the VMap, +/// the arguments are deleted from the resultant function. The VMap is /// updated to include mappings from all of the instructions and basicblocks in /// the function from their old to new values. /// -Function *CloneFunction(const Function *F, - std::map &ValueMap) { - std::vector ArgTypes; +Function *llvm::CloneFunction(const Function *F, ValueToValueMapTy &VMap, + bool ModuleLevelChanges, + ClonedCodeInfo *CodeInfo) { + std::vector ArgTypes; // The user might be deleting arguments to the function by specifying them in - // the ValueMap. If so, we need to not add the arguments to the arg ty vector + // the VMap. If so, we need to not add the arguments to the arg ty vector // - for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) - if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet? - ArgTypes.push_back(I->getType()); + for (const Argument &I : F->args()) + if (VMap.count(&I) == 0) // Haven't mapped the argument to anything yet? + ArgTypes.push_back(I.getType()); // Create a new function type... FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(), ArgTypes, F->getFunctionType()->isVarArg()); // Create the new function... - Function *NewF = new Function(FTy, F->hasInternalLinkage(), F->getName()); - + Function *NewF = Function::Create(FTy, F->getLinkage(), F->getName()); + // Loop over the arguments, copying the names of the mapped arguments over... - Function::aiterator DestI = NewF->abegin(); - for (Function::const_aiterator I = F->abegin(), E = F->aend(); I != E; ++I) - if (ValueMap.count(I) == 0) { // Is this argument preserved? - DestI->setName(I->getName()); // Copy the name over... - ValueMap[I] = DestI++; // Add mapping to ValueMap + Function::arg_iterator DestI = NewF->arg_begin(); + for (const Argument & I : F->args()) + if (VMap.count(&I) == 0) { // Is this argument preserved? + DestI->setName(I.getName()); // Copy the name over... + VMap[&I] = &*DestI++; // Add mapping to VMap + } + + if (ModuleLevelChanges) + CloneDebugInfoMetadata(NewF, F, VMap); + + SmallVector Returns; // Ignore returns cloned. + CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo); + return NewF; +} + + + +namespace { + /// This is a private class used to implement CloneAndPruneFunctionInto. + struct PruningFunctionCloner { + Function *NewFunc; + const Function *OldFunc; + ValueToValueMapTy &VMap; + bool ModuleLevelChanges; + const char *NameSuffix; + ClonedCodeInfo *CodeInfo; + + public: + PruningFunctionCloner(Function *newFunc, const Function *oldFunc, + ValueToValueMapTy &valueMap, bool moduleLevelChanges, + const char *nameSuffix, ClonedCodeInfo *codeInfo) + : NewFunc(newFunc), OldFunc(oldFunc), VMap(valueMap), + ModuleLevelChanges(moduleLevelChanges), NameSuffix(nameSuffix), + CodeInfo(codeInfo) {} + + /// The specified block is found to be reachable, clone it and + /// anything that it can reach. + void CloneBlock(const BasicBlock *BB, + BasicBlock::const_iterator StartingInst, + std::vector &ToClone); + }; +} + +/// The specified block is found to be reachable, clone it and +/// anything that it can reach. +void PruningFunctionCloner::CloneBlock(const BasicBlock *BB, + BasicBlock::const_iterator StartingInst, + std::vector &ToClone){ + WeakVH &BBEntry = VMap[BB]; + + // Have we already cloned this block? + if (BBEntry) return; + + // Nope, clone it now. + BasicBlock *NewBB; + BBEntry = NewBB = BasicBlock::Create(BB->getContext()); + if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix); + + // It is only legal to clone a function if a block address within that + // function is never referenced outside of the function. Given that, we + // want to map block addresses from the old function to block addresses in + // the clone. (This is different from the generic ValueMapper + // implementation, which generates an invalid blockaddress when + // cloning a function.) + // + // Note that we don't need to fix the mapping for unreachable blocks; + // the default mapping there is safe. + if (BB->hasAddressTaken()) { + Constant *OldBBAddr = BlockAddress::get(const_cast(OldFunc), + const_cast(BB)); + VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB); + } + + bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false; + + // Loop over all instructions, and copy them over, DCE'ing as we go. This + // loop doesn't include the terminator. + for (BasicBlock::const_iterator II = StartingInst, IE = --BB->end(); + II != IE; ++II) { + + Instruction *NewInst = II->clone(); + + // Eagerly remap operands to the newly cloned instruction, except for PHI + // nodes for which we defer processing until we update the CFG. + if (!isa(NewInst)) { + RemapInstruction(NewInst, VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges); + + // If we can simplify this instruction to some other value, simply add + // a mapping to that value rather than inserting a new instruction into + // the basic block. + if (Value *V = + SimplifyInstruction(NewInst, BB->getModule()->getDataLayout())) { + // On the off-chance that this simplifies to an instruction in the old + // function, map it back into the new function. + if (Value *MappedV = VMap.lookup(V)) + V = MappedV; + + VMap[&*II] = V; + delete NewInst; + continue; + } + } + + if (II->hasName()) + NewInst->setName(II->getName()+NameSuffix); + VMap[&*II] = NewInst; // Add instruction map to value. + NewBB->getInstList().push_back(NewInst); + hasCalls |= (isa(II) && !isa(II)); + + if (CodeInfo) + if (auto CS = ImmutableCallSite(&*II)) + if (CS.hasOperandBundles()) + CodeInfo->OperandBundleCallSites.push_back(NewInst); + + if (const AllocaInst *AI = dyn_cast(II)) { + if (isa(AI->getArraySize())) + hasStaticAllocas = true; + else + hasDynamicAllocas = true; + } + } + + // Finally, clone over the terminator. + const TerminatorInst *OldTI = BB->getTerminator(); + bool TerminatorDone = false; + if (const BranchInst *BI = dyn_cast(OldTI)) { + if (BI->isConditional()) { + // If the condition was a known constant in the callee... + ConstantInt *Cond = dyn_cast(BI->getCondition()); + // Or is a known constant in the caller... + if (!Cond) { + Value *V = VMap[BI->getCondition()]; + Cond = dyn_cast_or_null(V); + } + + // Constant fold to uncond branch! + if (Cond) { + BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue()); + VMap[OldTI] = BranchInst::Create(Dest, NewBB); + ToClone.push_back(Dest); + TerminatorDone = true; + } + } + } else if (const SwitchInst *SI = dyn_cast(OldTI)) { + // If switching on a value known constant in the caller. + ConstantInt *Cond = dyn_cast(SI->getCondition()); + if (!Cond) { // Or known constant after constant prop in the callee... + Value *V = VMap[SI->getCondition()]; + Cond = dyn_cast_or_null(V); } + if (Cond) { // Constant fold to uncond branch! + SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond); + BasicBlock *Dest = const_cast(Case.getCaseSuccessor()); + VMap[OldTI] = BranchInst::Create(Dest, NewBB); + ToClone.push_back(Dest); + TerminatorDone = true; + } + } + + if (!TerminatorDone) { + Instruction *NewInst = OldTI->clone(); + if (OldTI->hasName()) + NewInst->setName(OldTI->getName()+NameSuffix); + NewBB->getInstList().push_back(NewInst); + VMap[OldTI] = NewInst; // Add instruction map to value. + + if (CodeInfo) + if (auto CS = ImmutableCallSite(OldTI)) + if (CS.hasOperandBundles()) + CodeInfo->OperandBundleCallSites.push_back(NewInst); + + // Recursively clone any reachable successor blocks. + const TerminatorInst *TI = BB->getTerminator(); + for (const BasicBlock *Succ : TI->successors()) + ToClone.push_back(Succ); + } + + if (CodeInfo) { + CodeInfo->ContainsCalls |= hasCalls; + CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas; + CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas && + BB != &BB->getParent()->front(); + } +} + +/// This works like CloneAndPruneFunctionInto, except that it does not clone the +/// entire function. Instead it starts at an instruction provided by the caller +/// and copies (and prunes) only the code reachable from that instruction. +void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, + const Instruction *StartingInst, + ValueToValueMapTy &VMap, + bool ModuleLevelChanges, + SmallVectorImpl &Returns, + const char *NameSuffix, + ClonedCodeInfo *CodeInfo) { + assert(NameSuffix && "NameSuffix cannot be null!"); + + ValueMapTypeRemapper *TypeMapper = nullptr; + ValueMaterializer *Materializer = nullptr; + +#ifndef NDEBUG + // If the cloning starts at the beginning of the function, verify that + // the function arguments are mapped. + if (!StartingInst) + for (const Argument &II : OldFunc->args()) + assert(VMap.count(&II) && "No mapping from source argument specified!"); +#endif + + PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges, + NameSuffix, CodeInfo); + const BasicBlock *StartingBB; + if (StartingInst) + StartingBB = StartingInst->getParent(); + else { + StartingBB = &OldFunc->getEntryBlock(); + StartingInst = &StartingBB->front(); + } + + // Clone the entry block, and anything recursively reachable from it. + std::vector CloneWorklist; + PFC.CloneBlock(StartingBB, StartingInst->getIterator(), CloneWorklist); + while (!CloneWorklist.empty()) { + const BasicBlock *BB = CloneWorklist.back(); + CloneWorklist.pop_back(); + PFC.CloneBlock(BB, BB->begin(), CloneWorklist); + } + + // Loop over all of the basic blocks in the old function. If the block was + // reachable, we have cloned it and the old block is now in the value map: + // insert it into the new function in the right order. If not, ignore it. + // + // Defer PHI resolution until rest of function is resolved. + SmallVector PHIToResolve; + for (const BasicBlock &BI : *OldFunc) { + Value *V = VMap[&BI]; + BasicBlock *NewBB = cast_or_null(V); + if (!NewBB) continue; // Dead block. + + // Add the new block to the new function. + NewFunc->getBasicBlockList().push_back(NewBB); + + // Handle PHI nodes specially, as we have to remove references to dead + // blocks. + for (BasicBlock::const_iterator I = BI.begin(), E = BI.end(); I != E; ++I) { + // PHI nodes may have been remapped to non-PHI nodes by the caller or + // during the cloning process. + if (const PHINode *PN = dyn_cast(I)) { + if (isa(VMap[PN])) + PHIToResolve.push_back(PN); + else + break; + } else { + break; + } + } + + // Finally, remap the terminator instructions, as those can't be remapped + // until all BBs are mapped. + RemapInstruction(NewBB->getTerminator(), VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges, + TypeMapper, Materializer); + } + + // Defer PHI resolution until rest of function is resolved, PHI resolution + // requires the CFG to be up-to-date. + for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) { + const PHINode *OPN = PHIToResolve[phino]; + unsigned NumPreds = OPN->getNumIncomingValues(); + const BasicBlock *OldBB = OPN->getParent(); + BasicBlock *NewBB = cast(VMap[OldBB]); + + // Map operands for blocks that are live and remove operands for blocks + // that are dead. + for (; phino != PHIToResolve.size() && + PHIToResolve[phino]->getParent() == OldBB; ++phino) { + OPN = PHIToResolve[phino]; + PHINode *PN = cast(VMap[OPN]); + for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) { + Value *V = VMap[PN->getIncomingBlock(pred)]; + if (BasicBlock *MappedBlock = cast_or_null(V)) { + Value *InVal = MapValue(PN->getIncomingValue(pred), + VMap, + ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges); + assert(InVal && "Unknown input value?"); + PN->setIncomingValue(pred, InVal); + PN->setIncomingBlock(pred, MappedBlock); + } else { + PN->removeIncomingValue(pred, false); + --pred, --e; // Revisit the next entry. + } + } + } + + // The loop above has removed PHI entries for those blocks that are dead + // and has updated others. However, if a block is live (i.e. copied over) + // but its terminator has been changed to not go to this block, then our + // phi nodes will have invalid entries. Update the PHI nodes in this + // case. + PHINode *PN = cast(NewBB->begin()); + NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB)); + if (NumPreds != PN->getNumIncomingValues()) { + assert(NumPreds < PN->getNumIncomingValues()); + // Count how many times each predecessor comes to this block. + std::map PredCount; + for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB); + PI != E; ++PI) + --PredCount[*PI]; + + // Figure out how many entries to remove from each PHI. + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) + ++PredCount[PN->getIncomingBlock(i)]; + + // At this point, the excess predecessor entries are positive in the + // map. Loop over all of the PHIs and remove excess predecessor + // entries. + BasicBlock::iterator I = NewBB->begin(); + for (; (PN = dyn_cast(I)); ++I) { + for (std::map::iterator PCI =PredCount.begin(), + E = PredCount.end(); PCI != E; ++PCI) { + BasicBlock *Pred = PCI->first; + for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove) + PN->removeIncomingValue(Pred, false); + } + } + } + + // If the loops above have made these phi nodes have 0 or 1 operand, + // replace them with undef or the input value. We must do this for + // correctness, because 0-operand phis are not valid. + PN = cast(NewBB->begin()); + if (PN->getNumIncomingValues() == 0) { + BasicBlock::iterator I = NewBB->begin(); + BasicBlock::const_iterator OldI = OldBB->begin(); + while ((PN = dyn_cast(I++))) { + Value *NV = UndefValue::get(PN->getType()); + PN->replaceAllUsesWith(NV); + assert(VMap[&*OldI] == PN && "VMap mismatch"); + VMap[&*OldI] = NV; + PN->eraseFromParent(); + ++OldI; + } + } + } + + // Make a second pass over the PHINodes now that all of them have been + // remapped into the new function, simplifying the PHINode and performing any + // recursive simplifications exposed. This will transparently update the + // WeakVH in the VMap. Notably, we rely on that so that if we coalesce + // two PHINodes, the iteration over the old PHIs remains valid, and the + // mapping will just map us to the new node (which may not even be a PHI + // node). + for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx) + if (PHINode *PN = dyn_cast(VMap[PHIToResolve[Idx]])) + recursivelySimplifyInstruction(PN); + + // Now that the inlined function body has been fully constructed, go through + // and zap unconditional fall-through branches. This happens all the time when + // specializing code: code specialization turns conditional branches into + // uncond branches, and this code folds them. + Function::iterator Begin = cast(VMap[StartingBB])->getIterator(); + Function::iterator I = Begin; + while (I != NewFunc->end()) { + // Check if this block has become dead during inlining or other + // simplifications. Note that the first block will appear dead, as it has + // not yet been wired up properly. + if (I != Begin && (pred_begin(&*I) == pred_end(&*I) || + I->getSinglePredecessor() == &*I)) { + BasicBlock *DeadBB = &*I++; + DeleteDeadBlock(DeadBB); + continue; + } + + // We need to simplify conditional branches and switches with a constant + // operand. We try to prune these out when cloning, but if the + // simplification required looking through PHI nodes, those are only + // available after forming the full basic block. That may leave some here, + // and we still want to prune the dead code as early as possible. + ConstantFoldTerminator(&*I); + + BranchInst *BI = dyn_cast(I->getTerminator()); + if (!BI || BI->isConditional()) { ++I; continue; } + + BasicBlock *Dest = BI->getSuccessor(0); + if (!Dest->getSinglePredecessor()) { + ++I; continue; + } + + // We shouldn't be able to get single-entry PHI nodes here, as instsimplify + // above should have zapped all of them.. + assert(!isa(Dest->begin())); + + // We know all single-entry PHI nodes in the inlined function have been + // removed, so we just need to splice the blocks. + BI->eraseFromParent(); + + // Make all PHI nodes that referred to Dest now refer to I as their source. + Dest->replaceAllUsesWith(&*I); + + // Move all the instructions in the succ to the pred. + I->getInstList().splice(I->end(), Dest->getInstList()); + + // Remove the dest block. + Dest->eraseFromParent(); + + // Do not increment I, iteratively merge all things this block branches to. + } + + // Make a final pass over the basic blocks from the old function to gather + // any return instructions which survived folding. We have to do this here + // because we can iteratively remove and merge returns above. + for (Function::iterator I = cast(VMap[StartingBB])->getIterator(), + E = NewFunc->end(); + I != E; ++I) + if (ReturnInst *RI = dyn_cast(I->getTerminator())) + Returns.push_back(RI); +} + + +/// This works exactly like CloneFunctionInto, +/// except that it does some simple constant prop and DCE on the fly. The +/// effect of this is to copy significantly less code in cases where (for +/// example) a function call with constant arguments is inlined, and those +/// constant arguments cause a significant amount of code in the callee to be +/// dead. Since this doesn't produce an exact copy of the input, it can't be +/// used for things like CloneFunction or CloneModule. +void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc, + ValueToValueMapTy &VMap, + bool ModuleLevelChanges, + SmallVectorImpl &Returns, + const char *NameSuffix, + ClonedCodeInfo *CodeInfo, + Instruction *TheCall) { + CloneAndPruneIntoFromInst(NewFunc, OldFunc, &OldFunc->front().front(), VMap, + ModuleLevelChanges, Returns, NameSuffix, CodeInfo); +} + +/// \brief Remaps instructions in \p Blocks using the mapping in \p VMap. +void llvm::remapInstructionsInBlocks( + const SmallVectorImpl &Blocks, ValueToValueMapTy &VMap) { + // Rewrite the code to refer to itself. + for (auto *BB : Blocks) + for (auto &Inst : *BB) + RemapInstruction(&Inst, VMap, + RF_NoModuleLevelChanges | RF_IgnoreMissingEntries); +} + +/// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p +/// Blocks. +/// +/// Updates LoopInfo and DominatorTree assuming the loop is dominated by block +/// \p LoopDomBB. Insert the new blocks before block specified in \p Before. +Loop *llvm::cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB, + Loop *OrigLoop, ValueToValueMapTy &VMap, + const Twine &NameSuffix, LoopInfo *LI, + DominatorTree *DT, + SmallVectorImpl &Blocks) { + Function *F = OrigLoop->getHeader()->getParent(); + Loop *ParentLoop = OrigLoop->getParentLoop(); + + Loop *NewLoop = new Loop(); + if (ParentLoop) + ParentLoop->addChildLoop(NewLoop); + else + LI->addTopLevelLoop(NewLoop); + + BasicBlock *OrigPH = OrigLoop->getLoopPreheader(); + assert(OrigPH && "No preheader"); + BasicBlock *NewPH = CloneBasicBlock(OrigPH, VMap, NameSuffix, F); + // To rename the loop PHIs. + VMap[OrigPH] = NewPH; + Blocks.push_back(NewPH); + + // Update LoopInfo. + if (ParentLoop) + ParentLoop->addBasicBlockToLoop(NewPH, *LI); + + // Update DominatorTree. + DT->addNewBlock(NewPH, LoopDomBB); + + for (BasicBlock *BB : OrigLoop->getBlocks()) { + BasicBlock *NewBB = CloneBasicBlock(BB, VMap, NameSuffix, F); + VMap[BB] = NewBB; + + // Update LoopInfo. + NewLoop->addBasicBlockToLoop(NewBB, *LI); + + // Update DominatorTree. + BasicBlock *IDomBB = DT->getNode(BB)->getIDom()->getBlock(); + DT->addNewBlock(NewBB, cast(VMap[IDomBB])); + + Blocks.push_back(NewBB); + } + + // Move them physically from the end of the block list. + F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(), + NewPH); + F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(), + NewLoop->getHeader()->getIterator(), F->end()); - std::vector Returns; // Ignore returns cloned... - CloneFunctionInto(NewF, F, ValueMap, Returns); - return NewF; + return NewLoop; }