InlineFunction.cpp revision 206274
172339Sabial//===- InlineFunction.cpp - Code to perform function inlining -------------===// 272339Sabial// 372339Sabial// The LLVM Compiler Infrastructure 472339Sabial// 572339Sabial// This file is distributed under the University of Illinois Open Source 672339Sabial// License. See LICENSE.TXT for details. 772339Sabial// 872339Sabial//===----------------------------------------------------------------------===// 972339Sabial// 1072339Sabial// This file implements inlining of a function into a call site, resolving 1172339Sabial// parameters and the return value as appropriate. 1272339Sabial// 1372339Sabial//===----------------------------------------------------------------------===// 1472339Sabial 1572339Sabial#include "llvm/Transforms/Utils/Cloning.h" 1672339Sabial#include "llvm/Constants.h" 1772339Sabial#include "llvm/DerivedTypes.h" 1872339Sabial#include "llvm/LLVMContext.h" 1972339Sabial#include "llvm/Module.h" 2072339Sabial#include "llvm/Instructions.h" 2172339Sabial#include "llvm/IntrinsicInst.h" 2272339Sabial#include "llvm/Intrinsics.h" 2372339Sabial#include "llvm/Attributes.h" 2472339Sabial#include "llvm/Analysis/CallGraph.h" 2572339Sabial#include "llvm/Analysis/DebugInfo.h" 2672339Sabial#include "llvm/Target/TargetData.h" 2772339Sabial#include "llvm/ADT/SmallVector.h" 2872339Sabial#include "llvm/ADT/StringExtras.h" 2972339Sabial#include "llvm/Support/CallSite.h" 3072339Sabialusing namespace llvm; 3172339Sabial 3272339Sabialbool llvm::InlineFunction(CallInst *CI, CallGraph *CG, const TargetData *TD, 3372339Sabial SmallVectorImpl<AllocaInst*> *StaticAllocas) { 3472339Sabial return InlineFunction(CallSite(CI), CG, TD, StaticAllocas); 3572339Sabial} 3672339Sabialbool llvm::InlineFunction(InvokeInst *II, CallGraph *CG, const TargetData *TD, 3772339Sabial SmallVectorImpl<AllocaInst*> *StaticAllocas) { 3872339Sabial return InlineFunction(CallSite(II), CG, TD, StaticAllocas); 3972339Sabial} 4072339Sabial 4172339Sabial 4272339Sabial/// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into 4372339Sabial/// an invoke, we have to turn all of the calls that can throw into 4472339Sabial/// invokes. This function analyze BB to see if there are any calls, and if so, 4572339Sabial/// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI 4672339Sabial/// nodes in that block with the values specified in InvokeDestPHIValues. 4772339Sabial/// 4872339Sabialstatic void HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB, 4972339Sabial BasicBlock *InvokeDest, 5072339Sabial const SmallVectorImpl<Value*> &InvokeDestPHIValues) { 5172339Sabial for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) { 5272339Sabial Instruction *I = BBI++; 5372339Sabial 5472339Sabial // We only need to check for function calls: inlined invoke 5572339Sabial // instructions require no special handling. 5672339Sabial CallInst *CI = dyn_cast<CallInst>(I); 5772339Sabial if (CI == 0) continue; 5872339Sabial 5972339Sabial // If this call cannot unwind, don't convert it to an invoke. 6072339Sabial if (CI->doesNotThrow()) 6172339Sabial continue; 6272339Sabial 6372339Sabial // Convert this function call into an invoke instruction. 6472339Sabial // First, split the basic block. 6572339Sabial BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc"); 6672339Sabial 6772339Sabial // Next, create the new invoke instruction, inserting it at the end 6872339Sabial // of the old basic block. 6972339Sabial SmallVector<Value*, 8> InvokeArgs(CI->op_begin()+1, CI->op_end()); 7072339Sabial InvokeInst *II = 7172339Sabial InvokeInst::Create(CI->getCalledValue(), Split, InvokeDest, 7272339Sabial InvokeArgs.begin(), InvokeArgs.end(), 7372339Sabial CI->getName(), BB->getTerminator()); 7472339Sabial II->setCallingConv(CI->getCallingConv()); 7572339Sabial II->setAttributes(CI->getAttributes()); 7672339Sabial 7772339Sabial // Make sure that anything using the call now uses the invoke! This also 7872339Sabial // updates the CallGraph if present. 7972339Sabial CI->replaceAllUsesWith(II); 8072339Sabial 8172339Sabial // Delete the unconditional branch inserted by splitBasicBlock 8272339Sabial BB->getInstList().pop_back(); 8372339Sabial Split->getInstList().pop_front(); // Delete the original call 8472339Sabial 8572339Sabial // Update any PHI nodes in the exceptional block to indicate that 8672339Sabial // there is now a new entry in them. 8772339Sabial unsigned i = 0; 8872339Sabial for (BasicBlock::iterator I = InvokeDest->begin(); 8972339Sabial isa<PHINode>(I); ++I, ++i) 9072339Sabial cast<PHINode>(I)->addIncoming(InvokeDestPHIValues[i], BB); 9172339Sabial 9272339Sabial // This basic block is now complete, the caller will continue scanning the 9372339Sabial // next one. 9472339Sabial return; 9572339Sabial } 9672339Sabial} 9772339Sabial 9872339Sabial 9972339Sabial/// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls 10072339Sabial/// in the body of the inlined function into invokes and turn unwind 10172339Sabial/// instructions into branches to the invoke unwind dest. 10272339Sabial/// 10372339Sabial/// II is the invoke instruction being inlined. FirstNewBlock is the first 10472339Sabial/// block of the inlined code (the last block is the end of the function), 10572339Sabial/// and InlineCodeInfo is information about the code that got inlined. 10672339Sabialstatic void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock, 10772339Sabial ClonedCodeInfo &InlinedCodeInfo) { 10872339Sabial BasicBlock *InvokeDest = II->getUnwindDest(); 10972339Sabial SmallVector<Value*, 8> InvokeDestPHIValues; 11072339Sabial 11172339Sabial // If there are PHI nodes in the unwind destination block, we need to 11272339Sabial // keep track of which values came into them from this invoke, then remove 11372339Sabial // the entry for this block. 11472339Sabial BasicBlock *InvokeBlock = II->getParent(); 11572339Sabial for (BasicBlock::iterator I = InvokeDest->begin(); isa<PHINode>(I); ++I) { 11672339Sabial PHINode *PN = cast<PHINode>(I); 11772339Sabial // Save the value to use for this edge. 11872339Sabial InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(InvokeBlock)); 11972339Sabial } 12072339Sabial 12172339Sabial Function *Caller = FirstNewBlock->getParent(); 12272339Sabial 12372339Sabial // The inlined code is currently at the end of the function, scan from the 12472339Sabial // start of the inlined code to its end, checking for stuff we need to 12572339Sabial // rewrite. If the code doesn't have calls or unwinds, we know there is 12672339Sabial // nothing to rewrite. 12772339Sabial if (!InlinedCodeInfo.ContainsCalls && !InlinedCodeInfo.ContainsUnwinds) { 12872339Sabial // Now that everything is happy, we have one final detail. The PHI nodes in 12972339Sabial // the exception destination block still have entries due to the original 13072339Sabial // invoke instruction. Eliminate these entries (which might even delete the 13172339Sabial // PHI node) now. 13272339Sabial InvokeDest->removePredecessor(II->getParent()); 13372339Sabial return; 13472339Sabial } 13572339Sabial 13672339Sabial for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB){ 13772339Sabial if (InlinedCodeInfo.ContainsCalls) 13872339Sabial HandleCallsInBlockInlinedThroughInvoke(BB, InvokeDest, 13972339Sabial InvokeDestPHIValues); 14072339Sabial 14172339Sabial if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) { 14272339Sabial // An UnwindInst requires special handling when it gets inlined into an 14372339Sabial // invoke site. Once this happens, we know that the unwind would cause 14472339Sabial // a control transfer to the invoke exception destination, so we can 14572339Sabial // transform it into a direct branch to the exception destination. 14672339Sabial BranchInst::Create(InvokeDest, UI); 14772339Sabial 14872339Sabial // Delete the unwind instruction! 14972339Sabial UI->eraseFromParent(); 15072339Sabial 15172339Sabial // Update any PHI nodes in the exceptional block to indicate that 15272339Sabial // there is now a new entry in them. 15372339Sabial unsigned i = 0; 15472339Sabial for (BasicBlock::iterator I = InvokeDest->begin(); 15572339Sabial isa<PHINode>(I); ++I, ++i) { 15672339Sabial PHINode *PN = cast<PHINode>(I); 15772339Sabial PN->addIncoming(InvokeDestPHIValues[i], BB); 15872339Sabial } 15972339Sabial } 16072339Sabial } 16172339Sabial 16272339Sabial // Now that everything is happy, we have one final detail. The PHI nodes in 16372339Sabial // the exception destination block still have entries due to the original 16472339Sabial // invoke instruction. Eliminate these entries (which might even delete the 16572339Sabial // PHI node) now. 16672339Sabial InvokeDest->removePredecessor(II->getParent()); 16772339Sabial} 16872339Sabial 16972339Sabial/// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee 17072339Sabial/// into the caller, update the specified callgraph to reflect the changes we 17172339Sabial/// made. Note that it's possible that not all code was copied over, so only 17272339Sabial/// some edges of the callgraph may remain. 17372339Sabialstatic void UpdateCallGraphAfterInlining(CallSite CS, 17472339Sabial Function::iterator FirstNewBlock, 17572339Sabial DenseMap<const Value*, Value*> &ValueMap, 17672339Sabial CallGraph &CG) { 17772339Sabial const Function *Caller = CS.getInstruction()->getParent()->getParent(); 17872339Sabial const Function *Callee = CS.getCalledFunction(); 17972339Sabial CallGraphNode *CalleeNode = CG[Callee]; 18072339Sabial CallGraphNode *CallerNode = CG[Caller]; 18172339Sabial 18272339Sabial // Since we inlined some uninlined call sites in the callee into the caller, 18372339Sabial // add edges from the caller to all of the callees of the callee. 18472339Sabial CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end(); 18572339Sabial 18672339Sabial // Consider the case where CalleeNode == CallerNode. 18772339Sabial CallGraphNode::CalledFunctionsVector CallCache; 18872339Sabial if (CalleeNode == CallerNode) { 18972339Sabial CallCache.assign(I, E); 19072339Sabial I = CallCache.begin(); 19172339Sabial E = CallCache.end(); 19272339Sabial } 19372339Sabial 19472339Sabial for (; I != E; ++I) { 19572339Sabial const Value *OrigCall = I->first; 19672339Sabial 19772339Sabial DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall); 19872339Sabial // Only copy the edge if the call was inlined! 19972339Sabial if (VMI == ValueMap.end() || VMI->second == 0) 20072339Sabial continue; 20172339Sabial 20272339Sabial // If the call was inlined, but then constant folded, there is no edge to 20372339Sabial // add. Check for this case. 20472339Sabial if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second)) 20572339Sabial CallerNode->addCalledFunction(CallSite::get(NewCall), I->second); 20672339Sabial } 20772339Sabial 20872339Sabial // Update the call graph by deleting the edge from Callee to Caller. We must 20972339Sabial // do this after the loop above in case Caller and Callee are the same. 21072339Sabial CallerNode->removeCallEdgeFor(CS); 21172339Sabial} 21272339Sabial 21372339Sabial// InlineFunction - This function inlines the called function into the basic 21472339Sabial// block of the caller. This returns false if it is not possible to inline this 21572339Sabial// call. The program is still in a well defined state if this occurs though. 21672339Sabial// 21772339Sabial// Note that this only does one level of inlining. For example, if the 21872339Sabial// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now 21972339Sabial// exists in the instruction stream. Similiarly this will inline a recursive 22072339Sabial// function by one level. 22172339Sabial// 22272339Sabialbool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD, 22372339Sabial SmallVectorImpl<AllocaInst*> *StaticAllocas) { 22472339Sabial Instruction *TheCall = CS.getInstruction(); 22572339Sabial LLVMContext &Context = TheCall->getContext(); 22672339Sabial assert(TheCall->getParent() && TheCall->getParent()->getParent() && 22772339Sabial "Instruction not in function!"); 22872339Sabial 22972339Sabial const Function *CalledFunc = CS.getCalledFunction(); 23072339Sabial if (CalledFunc == 0 || // Can't inline external function or indirect 23172339Sabial CalledFunc->isDeclaration() || // call, or call to a vararg function! 23272339Sabial CalledFunc->getFunctionType()->isVarArg()) return false; 23372339Sabial 23472339Sabial 23572339Sabial // If the call to the callee is not a tail call, we must clear the 'tail' 23672339Sabial // flags on any calls that we inline. 23772339Sabial bool MustClearTailCallFlags = 23872339Sabial !(isa<CallInst>(TheCall) && cast<CallInst>(TheCall)->isTailCall()); 23972339Sabial 24072339Sabial // If the call to the callee cannot throw, set the 'nounwind' flag on any 24172339Sabial // calls that we inline. 24272339Sabial bool MarkNoUnwind = CS.doesNotThrow(); 24372339Sabial 24472339Sabial BasicBlock *OrigBB = TheCall->getParent(); 24572339Sabial Function *Caller = OrigBB->getParent(); 24672339Sabial 24772339Sabial // GC poses two hazards to inlining, which only occur when the callee has GC: 24872339Sabial // 1. If the caller has no GC, then the callee's GC must be propagated to the 24972339Sabial // caller. 25072339Sabial // 2. If the caller has a differing GC, it is invalid to inline. 25172339Sabial if (CalledFunc->hasGC()) { 25272339Sabial if (!Caller->hasGC()) 25372339Sabial Caller->setGC(CalledFunc->getGC()); 25472339Sabial else if (CalledFunc->getGC() != Caller->getGC()) 25572339Sabial return false; 25672339Sabial } 25772339Sabial 25872339Sabial // Get an iterator to the last basic block in the function, which will have 25972339Sabial // the new function inlined after it. 26072339Sabial // 26172339Sabial Function::iterator LastBlock = &Caller->back(); 26272339Sabial 26372339Sabial // Make sure to capture all of the return instructions from the cloned 26472339Sabial // function. 26572339Sabial SmallVector<ReturnInst*, 8> Returns; 26672339Sabial ClonedCodeInfo InlinedFunctionInfo; 26772339Sabial Function::iterator FirstNewBlock; 26872339Sabial 26972339Sabial { // Scope to destroy ValueMap after cloning. 27072339Sabial DenseMap<const Value*, Value*> ValueMap; 27172339Sabial 27272339Sabial assert(CalledFunc->arg_size() == CS.arg_size() && 27372339Sabial "No varargs calls can be inlined!"); 27472339Sabial 27572339Sabial // Calculate the vector of arguments to pass into the function cloner, which 27672339Sabial // matches up the formal to the actual argument values. 27772339Sabial CallSite::arg_iterator AI = CS.arg_begin(); 27872339Sabial unsigned ArgNo = 0; 27972339Sabial for (Function::const_arg_iterator I = CalledFunc->arg_begin(), 28072339Sabial E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) { 28172339Sabial Value *ActualArg = *AI; 28272339Sabial 28372339Sabial // When byval arguments actually inlined, we need to make the copy implied 28472339Sabial // by them explicit. However, we don't do this if the callee is readonly 28572339Sabial // or readnone, because the copy would be unneeded: the callee doesn't 28672339Sabial // modify the struct. 28772339Sabial if (CalledFunc->paramHasAttr(ArgNo+1, Attribute::ByVal) && 28872339Sabial !CalledFunc->onlyReadsMemory()) { 28972339Sabial const Type *AggTy = cast<PointerType>(I->getType())->getElementType(); 29072339Sabial const Type *VoidPtrTy = 29172339Sabial Type::getInt8PtrTy(Context); 29272339Sabial 29372339Sabial // Create the alloca. If we have TargetData, use nice alignment. 29472339Sabial unsigned Align = 1; 29572339Sabial if (TD) Align = TD->getPrefTypeAlignment(AggTy); 29672339Sabial Value *NewAlloca = new AllocaInst(AggTy, 0, Align, 29772339Sabial I->getName(), 29872339Sabial &*Caller->begin()->begin()); 29972339Sabial // Emit a memcpy. 30072339Sabial const Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)}; 30172339Sabial Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(), 30272339Sabial Intrinsic::memcpy, 30372339Sabial Tys, 3); 30472339Sabial Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall); 30572339Sabial Value *SrcCast = new BitCastInst(*AI, VoidPtrTy, "tmp", TheCall); 30672339Sabial 30772339Sabial Value *Size; 30872339Sabial if (TD == 0) 30972339Sabial Size = ConstantExpr::getSizeOf(AggTy); 31072339Sabial else 31172339Sabial Size = ConstantInt::get(Type::getInt64Ty(Context), 31272339Sabial TD->getTypeStoreSize(AggTy)); 31372339Sabial 31472339Sabial // Always generate a memcpy of alignment 1 here because we don't know 31572339Sabial // the alignment of the src pointer. Other optimizations can infer 31672339Sabial // better alignment. 31772339Sabial Value *CallArgs[] = { 31872339Sabial DestCast, SrcCast, Size, 31972339Sabial ConstantInt::get(Type::getInt32Ty(Context), 1), 32072339Sabial ConstantInt::get(Type::getInt1Ty(Context), 0) 32172339Sabial }; 32272339Sabial CallInst *TheMemCpy = 32372339Sabial CallInst::Create(MemCpyFn, CallArgs, CallArgs+5, "", TheCall); 32472339Sabial 32572339Sabial // If we have a call graph, update it. 32672339Sabial if (CG) { 32772339Sabial CallGraphNode *MemCpyCGN = CG->getOrInsertFunction(MemCpyFn); 32872339Sabial CallGraphNode *CallerNode = (*CG)[Caller]; 32972339Sabial CallerNode->addCalledFunction(TheMemCpy, MemCpyCGN); 33072339Sabial } 33172339Sabial 33272339Sabial // Uses of the argument in the function should use our new alloca 33372339Sabial // instead. 33472339Sabial ActualArg = NewAlloca; 33572339Sabial } 33672339Sabial 33772339Sabial ValueMap[I] = ActualArg; 33872339Sabial } 33972339Sabial 34072339Sabial // We want the inliner to prune the code as it copies. We would LOVE to 34172339Sabial // have no dead or constant instructions leftover after inlining occurs 34272339Sabial // (which can happen, e.g., because an argument was constant), but we'll be 34372339Sabial // happy with whatever the cloner can do. 34472339Sabial CloneAndPruneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i", 34572339Sabial &InlinedFunctionInfo, TD, TheCall); 34672339Sabial 34772339Sabial // Remember the first block that is newly cloned over. 34872339Sabial FirstNewBlock = LastBlock; ++FirstNewBlock; 34972339Sabial 35072339Sabial // Update the callgraph if requested. 35172339Sabial if (CG) 35272339Sabial UpdateCallGraphAfterInlining(CS, FirstNewBlock, ValueMap, *CG); 35372339Sabial } 35472339Sabial 35572339Sabial // If there are any alloca instructions in the block that used to be the entry 35672339Sabial // block for the callee, move them to the entry block of the caller. First 35772339Sabial // calculate which instruction they should be inserted before. We insert the 35872339Sabial // instructions at the end of the current alloca list. 35972339Sabial // 36072339Sabial { 36172339Sabial BasicBlock::iterator InsertPoint = Caller->begin()->begin(); 36272339Sabial for (BasicBlock::iterator I = FirstNewBlock->begin(), 36372339Sabial E = FirstNewBlock->end(); I != E; ) { 36472339Sabial AllocaInst *AI = dyn_cast<AllocaInst>(I++); 36572339Sabial if (AI == 0) continue; 36672339Sabial 36772339Sabial // If the alloca is now dead, remove it. This often occurs due to code 36872339Sabial // specialization. 36972339Sabial if (AI->use_empty()) { 37072339Sabial AI->eraseFromParent(); 37172339Sabial continue; 37272339Sabial } 37372339Sabial 37472339Sabial if (!isa<Constant>(AI->getArraySize())) 37572339Sabial continue; 37672339Sabial 37772339Sabial // Keep track of the static allocas that we inline into the caller if the 37872339Sabial // StaticAllocas pointer is non-null. 37972339Sabial if (StaticAllocas) StaticAllocas->push_back(AI); 38072339Sabial 38172339Sabial // Scan for the block of allocas that we can move over, and move them 38272339Sabial // all at once. 38372339Sabial while (isa<AllocaInst>(I) && 38472339Sabial isa<Constant>(cast<AllocaInst>(I)->getArraySize())) { 38572339Sabial if (StaticAllocas) StaticAllocas->push_back(cast<AllocaInst>(I)); 38672339Sabial ++I; 38772339Sabial } 38872339Sabial 38972339Sabial // Transfer all of the allocas over in a block. Using splice means 39072339Sabial // that the instructions aren't removed from the symbol table, then 39172339Sabial // reinserted. 39272339Sabial Caller->getEntryBlock().getInstList().splice(InsertPoint, 39372339Sabial FirstNewBlock->getInstList(), 39472339Sabial AI, I); 39572339Sabial } 39672339Sabial } 39772339Sabial 39872339Sabial // If the inlined code contained dynamic alloca instructions, wrap the inlined 39972339Sabial // code with llvm.stacksave/llvm.stackrestore intrinsics. 40072339Sabial if (InlinedFunctionInfo.ContainsDynamicAllocas) { 40172339Sabial Module *M = Caller->getParent(); 40272339Sabial // Get the two intrinsics we care about. 40372339Sabial Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave); 40472339Sabial Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore); 40572339Sabial 40672339Sabial // If we are preserving the callgraph, add edges to the stacksave/restore 40772339Sabial // functions for the calls we insert. 40872339Sabial CallGraphNode *StackSaveCGN = 0, *StackRestoreCGN = 0, *CallerNode = 0; 40972339Sabial if (CG) { 41072339Sabial StackSaveCGN = CG->getOrInsertFunction(StackSave); 41172339Sabial StackRestoreCGN = CG->getOrInsertFunction(StackRestore); 41272339Sabial CallerNode = (*CG)[Caller]; 41372339Sabial } 41472339Sabial 41572339Sabial // Insert the llvm.stacksave. 41672339Sabial CallInst *SavedPtr = CallInst::Create(StackSave, "savedstack", 41772339Sabial FirstNewBlock->begin()); 41872339Sabial if (CG) CallerNode->addCalledFunction(SavedPtr, StackSaveCGN); 41972339Sabial 42072339Sabial // Insert a call to llvm.stackrestore before any return instructions in the 42172339Sabial // inlined function. 42272339Sabial for (unsigned i = 0, e = Returns.size(); i != e; ++i) { 42372339Sabial CallInst *CI = CallInst::Create(StackRestore, SavedPtr, "", Returns[i]); 42472339Sabial if (CG) CallerNode->addCalledFunction(CI, StackRestoreCGN); 42572339Sabial } 42672339Sabial 42772339Sabial // Count the number of StackRestore calls we insert. 42872339Sabial unsigned NumStackRestores = Returns.size(); 42972339Sabial 43072339Sabial // If we are inlining an invoke instruction, insert restores before each 43172339Sabial // unwind. These unwinds will be rewritten into branches later. 43272339Sabial if (InlinedFunctionInfo.ContainsUnwinds && isa<InvokeInst>(TheCall)) { 43372339Sabial for (Function::iterator BB = FirstNewBlock, E = Caller->end(); 43472339Sabial BB != E; ++BB) 43572339Sabial if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) { 43672339Sabial CallInst *CI = CallInst::Create(StackRestore, SavedPtr, "", UI); 43772339Sabial if (CG) CallerNode->addCalledFunction(CI, StackRestoreCGN); 43872339Sabial ++NumStackRestores; 43972339Sabial } 44072339Sabial } 44172339Sabial } 44272339Sabial 44372339Sabial // If we are inlining tail call instruction through a call site that isn't 44472339Sabial // marked 'tail', we must remove the tail marker for any calls in the inlined 44572339Sabial // code. Also, calls inlined through a 'nounwind' call site should be marked 44672339Sabial // 'nounwind'. 44772339Sabial if (InlinedFunctionInfo.ContainsCalls && 44872339Sabial (MustClearTailCallFlags || MarkNoUnwind)) { 44972339Sabial for (Function::iterator BB = FirstNewBlock, E = Caller->end(); 45072339Sabial BB != E; ++BB) 45172339Sabial for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 45272339Sabial if (CallInst *CI = dyn_cast<CallInst>(I)) { 45372339Sabial if (MustClearTailCallFlags) 45472339Sabial CI->setTailCall(false); 45572339Sabial if (MarkNoUnwind) 45672339Sabial CI->setDoesNotThrow(); 45772339Sabial } 45872339Sabial } 45972339Sabial 46072339Sabial // If we are inlining through a 'nounwind' call site then any inlined 'unwind' 46172339Sabial // instructions are unreachable. 46272339Sabial if (InlinedFunctionInfo.ContainsUnwinds && MarkNoUnwind) 46372339Sabial for (Function::iterator BB = FirstNewBlock, E = Caller->end(); 46472339Sabial BB != E; ++BB) { 46572339Sabial TerminatorInst *Term = BB->getTerminator(); 46672339Sabial if (isa<UnwindInst>(Term)) { 46772339Sabial new UnreachableInst(Context, Term); 46872339Sabial BB->getInstList().erase(Term); 46972339Sabial } 47072339Sabial } 47172339Sabial 47272339Sabial // If we are inlining for an invoke instruction, we must make sure to rewrite 47372339Sabial // any inlined 'unwind' instructions into branches to the invoke exception 47472339Sabial // destination, and call instructions into invoke instructions. 47572339Sabial if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) 47672339Sabial HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo); 47772339Sabial 47872339Sabial // If we cloned in _exactly one_ basic block, and if that block ends in a 47972339Sabial // return instruction, we splice the body of the inlined callee directly into 48072339Sabial // the calling basic block. 48172339Sabial if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) { 48272339Sabial // Move all of the instructions right before the call. 48372339Sabial OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(), 48472339Sabial FirstNewBlock->begin(), FirstNewBlock->end()); 48572339Sabial // Remove the cloned basic block. 48672339Sabial Caller->getBasicBlockList().pop_back(); 48772339Sabial 48872339Sabial // If the call site was an invoke instruction, add a branch to the normal 48972339Sabial // destination. 49072339Sabial if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) 49172339Sabial BranchInst::Create(II->getNormalDest(), TheCall); 49272339Sabial 49372339Sabial // If the return instruction returned a value, replace uses of the call with 49472339Sabial // uses of the returned value. 49572339Sabial if (!TheCall->use_empty()) { 49672339Sabial ReturnInst *R = Returns[0]; 49772339Sabial if (TheCall == R->getReturnValue()) 49872339Sabial TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType())); 49972339Sabial else 50072339Sabial TheCall->replaceAllUsesWith(R->getReturnValue()); 50172339Sabial } 50272339Sabial // Since we are now done with the Call/Invoke, we can delete it. 50372339Sabial TheCall->eraseFromParent(); 50472339Sabial 50572339Sabial // Since we are now done with the return instruction, delete it also. 50672339Sabial Returns[0]->eraseFromParent(); 50772339Sabial 50872339Sabial // We are now done with the inlining. 50972339Sabial return true; 51072339Sabial } 51172339Sabial 51272339Sabial // Otherwise, we have the normal case, of more than one block to inline or 51372339Sabial // multiple return sites. 51472339Sabial 51572339Sabial // We want to clone the entire callee function into the hole between the 51672339Sabial // "starter" and "ender" blocks. How we accomplish this depends on whether 51772339Sabial // this is an invoke instruction or a call instruction. 51872339Sabial BasicBlock *AfterCallBB; 51972339Sabial if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) { 52072339Sabial 52172339Sabial // Add an unconditional branch to make this look like the CallInst case... 52272339Sabial BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall); 52372339Sabial 52472339Sabial // Split the basic block. This guarantees that no PHI nodes will have to be 52572339Sabial // updated due to new incoming edges, and make the invoke case more 52672339Sabial // symmetric to the call case. 52772339Sabial AfterCallBB = OrigBB->splitBasicBlock(NewBr, 52872339Sabial CalledFunc->getName()+".exit"); 52972339Sabial 53072339Sabial } else { // It's a call 53172339Sabial // If this is a call instruction, we need to split the basic block that 53272339Sabial // the call lives in. 53372339Sabial // 53472339Sabial AfterCallBB = OrigBB->splitBasicBlock(TheCall, 53572339Sabial CalledFunc->getName()+".exit"); 53672339Sabial } 53772339Sabial 53872339Sabial // Change the branch that used to go to AfterCallBB to branch to the first 53972339Sabial // basic block of the inlined function. 54072339Sabial // 54172339Sabial TerminatorInst *Br = OrigBB->getTerminator(); 54272339Sabial assert(Br && Br->getOpcode() == Instruction::Br && 54372339Sabial "splitBasicBlock broken!"); 54472339Sabial Br->setOperand(0, FirstNewBlock); 54572339Sabial 54672339Sabial 54772339Sabial // Now that the function is correct, make it a little bit nicer. In 54872339Sabial // particular, move the basic blocks inserted from the end of the function 54972339Sabial // into the space made by splitting the source basic block. 55072339Sabial Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(), 55172339Sabial FirstNewBlock, Caller->end()); 55272339Sabial 55372339Sabial // Handle all of the return instructions that we just cloned in, and eliminate 55472339Sabial // any users of the original call/invoke instruction. 55572339Sabial const Type *RTy = CalledFunc->getReturnType(); 55672339Sabial 55772339Sabial if (Returns.size() > 1) { 55872339Sabial // The PHI node should go at the front of the new basic block to merge all 55972339Sabial // possible incoming values. 56072339Sabial PHINode *PHI = 0; 56172339Sabial if (!TheCall->use_empty()) { 56272339Sabial PHI = PHINode::Create(RTy, TheCall->getName(), 56372339Sabial AfterCallBB->begin()); 56472339Sabial // Anything that used the result of the function call should now use the 56572339Sabial // PHI node as their operand. 56672339Sabial TheCall->replaceAllUsesWith(PHI); 56772339Sabial } 56872339Sabial 56972339Sabial // Loop over all of the return instructions adding entries to the PHI node 57072339Sabial // as appropriate. 57172339Sabial if (PHI) { 57272339Sabial for (unsigned i = 0, e = Returns.size(); i != e; ++i) { 57372339Sabial ReturnInst *RI = Returns[i]; 57472339Sabial assert(RI->getReturnValue()->getType() == PHI->getType() && 57572339Sabial "Ret value not consistent in function!"); 57672339Sabial PHI->addIncoming(RI->getReturnValue(), RI->getParent()); 57772339Sabial } 57872339Sabial 57972339Sabial // Now that we inserted the PHI, check to see if it has a single value 58072339Sabial // (e.g. all the entries are the same or undef). If so, remove the PHI so 58172339Sabial // it doesn't block other optimizations. 58272339Sabial if (Value *V = PHI->hasConstantValue()) { 58372339Sabial PHI->replaceAllUsesWith(V); 58472339Sabial PHI->eraseFromParent(); 58572339Sabial } 58672339Sabial } 58772339Sabial 58872339Sabial 58972339Sabial // Add a branch to the merge points and remove return instructions. 59072339Sabial for (unsigned i = 0, e = Returns.size(); i != e; ++i) { 59172339Sabial ReturnInst *RI = Returns[i]; 59272339Sabial BranchInst::Create(AfterCallBB, RI); 59372339Sabial RI->eraseFromParent(); 59472339Sabial } 59572339Sabial } else if (!Returns.empty()) { 59672339Sabial // Otherwise, if there is exactly one return value, just replace anything 59772339Sabial // using the return value of the call with the computed value. 59872339Sabial if (!TheCall->use_empty()) { 59972339Sabial if (TheCall == Returns[0]->getReturnValue()) 60072339Sabial TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType())); 60172339Sabial else 60272339Sabial TheCall->replaceAllUsesWith(Returns[0]->getReturnValue()); 60372339Sabial } 60472339Sabial 60572339Sabial // Splice the code from the return block into the block that it will return 60672339Sabial // to, which contains the code that was after the call. 60772339Sabial BasicBlock *ReturnBB = Returns[0]->getParent(); 60872339Sabial AfterCallBB->getInstList().splice(AfterCallBB->begin(), 60972339Sabial ReturnBB->getInstList()); 61072339Sabial 61172339Sabial // Update PHI nodes that use the ReturnBB to use the AfterCallBB. 61272339Sabial ReturnBB->replaceAllUsesWith(AfterCallBB); 61372339Sabial 61472339Sabial // Delete the return instruction now and empty ReturnBB now. 61572339Sabial Returns[0]->eraseFromParent(); 61672339Sabial ReturnBB->eraseFromParent(); 61772339Sabial } else if (!TheCall->use_empty()) { 61872339Sabial // No returns, but something is using the return value of the call. Just 61972339Sabial // nuke the result. 62072339Sabial TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType())); 62172339Sabial } 62272339Sabial 62372339Sabial // Since we are now done with the Call/Invoke, we can delete it. 62472339Sabial TheCall->eraseFromParent(); 62572339Sabial 62672339Sabial // We should always be able to fold the entry block of the function into the 62772339Sabial // single predecessor of the block... 62872339Sabial assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!"); 62972339Sabial BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0); 63072339Sabial 63172339Sabial // Splice the code entry block into calling block, right before the 63272339Sabial // unconditional branch. 63372339Sabial OrigBB->getInstList().splice(Br, CalleeEntry->getInstList()); 63472339Sabial CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes 63572339Sabial 63672339Sabial // Remove the unconditional branch. 63772339Sabial OrigBB->getInstList().erase(Br); 63872339Sabial 63972339Sabial // Now we can remove the CalleeEntry block, which is now empty. 64072339Sabial Caller->getBasicBlockList().erase(CalleeEntry); 64172339Sabial 64272339Sabial return true; 64372339Sabial} 64472339Sabial