1 //===- InlineFunction.cpp - Code to perform function inlining -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements inlining of a function into a call site, resolving
11 // parameters and the return value as appropriate.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Utils/Cloning.h"
16 #include "llvm/ADT/SmallSet.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/SetVector.h"
19 #include "llvm/ADT/StringExtras.h"
20 #include "llvm/Analysis/AliasAnalysis.h"
21 #include "llvm/Analysis/AssumptionTracker.h"
22 #include "llvm/Analysis/CallGraph.h"
23 #include "llvm/Analysis/CaptureTracking.h"
24 #include "llvm/Analysis/InstructionSimplify.h"
25 #include "llvm/Analysis/ValueTracking.h"
26 #include "llvm/IR/Attributes.h"
27 #include "llvm/IR/CallSite.h"
28 #include "llvm/IR/CFG.h"
29 #include "llvm/IR/Constants.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/DebugInfo.h"
32 #include "llvm/IR/DerivedTypes.h"
33 #include "llvm/IR/Dominators.h"
34 #include "llvm/IR/IRBuilder.h"
35 #include "llvm/IR/Instructions.h"
36 #include "llvm/IR/IntrinsicInst.h"
37 #include "llvm/IR/Intrinsics.h"
38 #include "llvm/IR/MDBuilder.h"
39 #include "llvm/IR/Module.h"
40 #include "llvm/Transforms/Utils/Local.h"
41 #include "llvm/Support/CommandLine.h"
46 EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(true),
48 cl::desc("Convert noalias attributes to metadata during inlining."));
50 bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
51 bool InsertLifetime) {
52 return InlineFunction(CallSite(CI), IFI, InsertLifetime);
54 bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
55 bool InsertLifetime) {
56 return InlineFunction(CallSite(II), IFI, InsertLifetime);
60 /// A class for recording information about inlining through an invoke.
61 class InvokeInliningInfo {
62 BasicBlock *OuterResumeDest; ///< Destination of the invoke's unwind.
63 BasicBlock *InnerResumeDest; ///< Destination for the callee's resume.
64 LandingPadInst *CallerLPad; ///< LandingPadInst associated with the invoke.
65 PHINode *InnerEHValuesPHI; ///< PHI for EH values from landingpad insts.
66 SmallVector<Value*, 8> UnwindDestPHIValues;
69 InvokeInliningInfo(InvokeInst *II)
70 : OuterResumeDest(II->getUnwindDest()), InnerResumeDest(nullptr),
71 CallerLPad(nullptr), InnerEHValuesPHI(nullptr) {
72 // If there are PHI nodes in the unwind destination block, we need to keep
73 // track of which values came into them from the invoke before removing
74 // the edge from this block.
75 llvm::BasicBlock *InvokeBB = II->getParent();
76 BasicBlock::iterator I = OuterResumeDest->begin();
77 for (; isa<PHINode>(I); ++I) {
78 // Save the value to use for this edge.
79 PHINode *PHI = cast<PHINode>(I);
80 UnwindDestPHIValues.push_back(PHI->getIncomingValueForBlock(InvokeBB));
83 CallerLPad = cast<LandingPadInst>(I);
86 /// getOuterResumeDest - The outer unwind destination is the target of
87 /// unwind edges introduced for calls within the inlined function.
88 BasicBlock *getOuterResumeDest() const {
89 return OuterResumeDest;
92 BasicBlock *getInnerResumeDest();
94 LandingPadInst *getLandingPadInst() const { return CallerLPad; }
96 /// forwardResume - Forward the 'resume' instruction to the caller's landing
97 /// pad block. When the landing pad block has only one predecessor, this is
98 /// a simple branch. When there is more than one predecessor, we need to
99 /// split the landing pad block after the landingpad instruction and jump
101 void forwardResume(ResumeInst *RI,
102 SmallPtrSetImpl<LandingPadInst*> &InlinedLPads);
104 /// addIncomingPHIValuesFor - Add incoming-PHI values to the unwind
105 /// destination block for the given basic block, using the values for the
106 /// original invoke's source block.
107 void addIncomingPHIValuesFor(BasicBlock *BB) const {
108 addIncomingPHIValuesForInto(BB, OuterResumeDest);
111 void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
112 BasicBlock::iterator I = dest->begin();
113 for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
114 PHINode *phi = cast<PHINode>(I);
115 phi->addIncoming(UnwindDestPHIValues[i], src);
121 /// getInnerResumeDest - Get or create a target for the branch from ResumeInsts.
122 BasicBlock *InvokeInliningInfo::getInnerResumeDest() {
123 if (InnerResumeDest) return InnerResumeDest;
125 // Split the landing pad.
126 BasicBlock::iterator SplitPoint = CallerLPad; ++SplitPoint;
128 OuterResumeDest->splitBasicBlock(SplitPoint,
129 OuterResumeDest->getName() + ".body");
131 // The number of incoming edges we expect to the inner landing pad.
132 const unsigned PHICapacity = 2;
134 // Create corresponding new PHIs for all the PHIs in the outer landing pad.
135 BasicBlock::iterator InsertPoint = InnerResumeDest->begin();
136 BasicBlock::iterator I = OuterResumeDest->begin();
137 for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
138 PHINode *OuterPHI = cast<PHINode>(I);
139 PHINode *InnerPHI = PHINode::Create(OuterPHI->getType(), PHICapacity,
140 OuterPHI->getName() + ".lpad-body",
142 OuterPHI->replaceAllUsesWith(InnerPHI);
143 InnerPHI->addIncoming(OuterPHI, OuterResumeDest);
146 // Create a PHI for the exception values.
147 InnerEHValuesPHI = PHINode::Create(CallerLPad->getType(), PHICapacity,
148 "eh.lpad-body", InsertPoint);
149 CallerLPad->replaceAllUsesWith(InnerEHValuesPHI);
150 InnerEHValuesPHI->addIncoming(CallerLPad, OuterResumeDest);
153 return InnerResumeDest;
156 /// forwardResume - Forward the 'resume' instruction to the caller's landing pad
157 /// block. When the landing pad block has only one predecessor, this is a simple
158 /// branch. When there is more than one predecessor, we need to split the
159 /// landing pad block after the landingpad instruction and jump to there.
160 void InvokeInliningInfo::forwardResume(ResumeInst *RI,
161 SmallPtrSetImpl<LandingPadInst*> &InlinedLPads) {
162 BasicBlock *Dest = getInnerResumeDest();
163 BasicBlock *Src = RI->getParent();
165 BranchInst::Create(Dest, Src);
167 // Update the PHIs in the destination. They were inserted in an order which
169 addIncomingPHIValuesForInto(Src, Dest);
171 InnerEHValuesPHI->addIncoming(RI->getOperand(0), Src);
172 RI->eraseFromParent();
175 /// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
176 /// an invoke, we have to turn all of the calls that can throw into
177 /// invokes. This function analyze BB to see if there are any calls, and if so,
178 /// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
179 /// nodes in that block with the values specified in InvokeDestPHIValues.
180 static void HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
181 InvokeInliningInfo &Invoke) {
182 for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
183 Instruction *I = BBI++;
185 // We only need to check for function calls: inlined invoke
186 // instructions require no special handling.
187 CallInst *CI = dyn_cast<CallInst>(I);
189 // If this call cannot unwind, don't convert it to an invoke.
190 // Inline asm calls cannot throw.
191 if (!CI || CI->doesNotThrow() || isa<InlineAsm>(CI->getCalledValue()))
194 // Convert this function call into an invoke instruction. First, split the
196 BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
198 // Delete the unconditional branch inserted by splitBasicBlock
199 BB->getInstList().pop_back();
201 // Create the new invoke instruction.
202 ImmutableCallSite CS(CI);
203 SmallVector<Value*, 8> InvokeArgs(CS.arg_begin(), CS.arg_end());
204 InvokeInst *II = InvokeInst::Create(CI->getCalledValue(), Split,
205 Invoke.getOuterResumeDest(),
206 InvokeArgs, CI->getName(), BB);
207 II->setDebugLoc(CI->getDebugLoc());
208 II->setCallingConv(CI->getCallingConv());
209 II->setAttributes(CI->getAttributes());
211 // Make sure that anything using the call now uses the invoke! This also
212 // updates the CallGraph if present, because it uses a WeakVH.
213 CI->replaceAllUsesWith(II);
215 // Delete the original call
216 Split->getInstList().pop_front();
218 // Update any PHI nodes in the exceptional block to indicate that there is
219 // now a new entry in them.
220 Invoke.addIncomingPHIValuesFor(BB);
225 /// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
226 /// in the body of the inlined function into invokes.
228 /// II is the invoke instruction being inlined. FirstNewBlock is the first
229 /// block of the inlined code (the last block is the end of the function),
230 /// and InlineCodeInfo is information about the code that got inlined.
231 static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
232 ClonedCodeInfo &InlinedCodeInfo) {
233 BasicBlock *InvokeDest = II->getUnwindDest();
235 Function *Caller = FirstNewBlock->getParent();
237 // The inlined code is currently at the end of the function, scan from the
238 // start of the inlined code to its end, checking for stuff we need to
240 InvokeInliningInfo Invoke(II);
242 // Get all of the inlined landing pad instructions.
243 SmallPtrSet<LandingPadInst*, 16> InlinedLPads;
244 for (Function::iterator I = FirstNewBlock, E = Caller->end(); I != E; ++I)
245 if (InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator()))
246 InlinedLPads.insert(II->getLandingPadInst());
248 // Append the clauses from the outer landing pad instruction into the inlined
249 // landing pad instructions.
250 LandingPadInst *OuterLPad = Invoke.getLandingPadInst();
251 for (LandingPadInst *InlinedLPad : InlinedLPads) {
252 unsigned OuterNum = OuterLPad->getNumClauses();
253 InlinedLPad->reserveClauses(OuterNum);
254 for (unsigned OuterIdx = 0; OuterIdx != OuterNum; ++OuterIdx)
255 InlinedLPad->addClause(OuterLPad->getClause(OuterIdx));
256 if (OuterLPad->isCleanup())
257 InlinedLPad->setCleanup(true);
260 for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB){
261 if (InlinedCodeInfo.ContainsCalls)
262 HandleCallsInBlockInlinedThroughInvoke(BB, Invoke);
264 // Forward any resumes that are remaining here.
265 if (ResumeInst *RI = dyn_cast<ResumeInst>(BB->getTerminator()))
266 Invoke.forwardResume(RI, InlinedLPads);
269 // Now that everything is happy, we have one final detail. The PHI nodes in
270 // the exception destination block still have entries due to the original
271 // invoke instruction. Eliminate these entries (which might even delete the
273 InvokeDest->removePredecessor(II->getParent());
276 /// CloneAliasScopeMetadata - When inlining a function that contains noalias
277 /// scope metadata, this metadata needs to be cloned so that the inlined blocks
278 /// have different "unqiue scopes" at every call site. Were this not done, then
279 /// aliasing scopes from a function inlined into a caller multiple times could
280 /// not be differentiated (and this would lead to miscompiles because the
281 /// non-aliasing property communicated by the metadata could have
282 /// call-site-specific control dependencies).
283 static void CloneAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap) {
284 const Function *CalledFunc = CS.getCalledFunction();
285 SetVector<const MDNode *> MD;
287 // Note: We could only clone the metadata if it is already used in the
288 // caller. I'm omitting that check here because it might confuse
289 // inter-procedural alias analysis passes. We can revisit this if it becomes
290 // an efficiency or overhead problem.
292 for (Function::const_iterator I = CalledFunc->begin(), IE = CalledFunc->end();
294 for (BasicBlock::const_iterator J = I->begin(), JE = I->end(); J != JE; ++J) {
295 if (const MDNode *M = J->getMetadata(LLVMContext::MD_alias_scope))
297 if (const MDNode *M = J->getMetadata(LLVMContext::MD_noalias))
304 // Walk the existing metadata, adding the complete (perhaps cyclic) chain to
306 SmallVector<const Value *, 16> Queue(MD.begin(), MD.end());
307 while (!Queue.empty()) {
308 const MDNode *M = cast<MDNode>(Queue.pop_back_val());
309 for (unsigned i = 0, ie = M->getNumOperands(); i != ie; ++i)
310 if (const MDNode *M1 = dyn_cast<MDNode>(M->getOperand(i)))
315 // Now we have a complete set of all metadata in the chains used to specify
316 // the noalias scopes and the lists of those scopes.
317 SmallVector<MDNode *, 16> DummyNodes;
318 DenseMap<const MDNode *, TrackingVH<MDNode> > MDMap;
319 for (SetVector<const MDNode *>::iterator I = MD.begin(), IE = MD.end();
321 MDNode *Dummy = MDNode::getTemporary(CalledFunc->getContext(), None);
322 DummyNodes.push_back(Dummy);
326 // Create new metadata nodes to replace the dummy nodes, replacing old
327 // metadata references with either a dummy node or an already-created new
329 for (SetVector<const MDNode *>::iterator I = MD.begin(), IE = MD.end();
331 SmallVector<Value *, 4> NewOps;
332 for (unsigned i = 0, ie = (*I)->getNumOperands(); i != ie; ++i) {
333 const Value *V = (*I)->getOperand(i);
334 if (const MDNode *M = dyn_cast<MDNode>(V))
335 NewOps.push_back(MDMap[M]);
337 NewOps.push_back(const_cast<Value *>(V));
340 MDNode *NewM = MDNode::get(CalledFunc->getContext(), NewOps),
343 TempM->replaceAllUsesWith(NewM);
346 // Now replace the metadata in the new inlined instructions with the
347 // repacements from the map.
348 for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
349 VMI != VMIE; ++VMI) {
353 Instruction *NI = dyn_cast<Instruction>(VMI->second);
357 if (MDNode *M = NI->getMetadata(LLVMContext::MD_alias_scope)) {
358 MDNode *NewMD = MDMap[M];
359 // If the call site also had alias scope metadata (a list of scopes to
360 // which instructions inside it might belong), propagate those scopes to
361 // the inlined instructions.
363 CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
364 NewMD = MDNode::concatenate(NewMD, CSM);
365 NI->setMetadata(LLVMContext::MD_alias_scope, NewMD);
366 } else if (NI->mayReadOrWriteMemory()) {
368 CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
369 NI->setMetadata(LLVMContext::MD_alias_scope, M);
372 if (MDNode *M = NI->getMetadata(LLVMContext::MD_noalias)) {
373 MDNode *NewMD = MDMap[M];
374 // If the call site also had noalias metadata (a list of scopes with
375 // which instructions inside it don't alias), propagate those scopes to
376 // the inlined instructions.
378 CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
379 NewMD = MDNode::concatenate(NewMD, CSM);
380 NI->setMetadata(LLVMContext::MD_noalias, NewMD);
381 } else if (NI->mayReadOrWriteMemory()) {
383 CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
384 NI->setMetadata(LLVMContext::MD_noalias, M);
388 // Now that everything has been replaced, delete the dummy nodes.
389 for (unsigned i = 0, ie = DummyNodes.size(); i != ie; ++i)
390 MDNode::deleteTemporary(DummyNodes[i]);
393 /// AddAliasScopeMetadata - If the inlined function has noalias arguments, then
394 /// add new alias scopes for each noalias argument, tag the mapped noalias
395 /// parameters with noalias metadata specifying the new scope, and tag all
396 /// non-derived loads, stores and memory intrinsics with the new alias scopes.
397 static void AddAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap,
398 const DataLayout *DL, AliasAnalysis *AA) {
399 if (!EnableNoAliasConversion)
402 const Function *CalledFunc = CS.getCalledFunction();
403 SmallVector<const Argument *, 4> NoAliasArgs;
405 for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
406 E = CalledFunc->arg_end(); I != E; ++I) {
407 if (I->hasNoAliasAttr() && !I->hasNUses(0))
408 NoAliasArgs.push_back(I);
411 if (NoAliasArgs.empty())
414 // To do a good job, if a noalias variable is captured, we need to know if
415 // the capture point dominates the particular use we're considering.
417 DT.recalculate(const_cast<Function&>(*CalledFunc));
419 // noalias indicates that pointer values based on the argument do not alias
420 // pointer values which are not based on it. So we add a new "scope" for each
421 // noalias function argument. Accesses using pointers based on that argument
422 // become part of that alias scope, accesses using pointers not based on that
423 // argument are tagged as noalias with that scope.
425 DenseMap<const Argument *, MDNode *> NewScopes;
426 MDBuilder MDB(CalledFunc->getContext());
428 // Create a new scope domain for this function.
430 MDB.createAnonymousAliasScopeDomain(CalledFunc->getName());
431 for (unsigned i = 0, e = NoAliasArgs.size(); i != e; ++i) {
432 const Argument *A = NoAliasArgs[i];
434 std::string Name = CalledFunc->getName();
437 Name += A->getName();
439 Name += ": argument ";
443 // Note: We always create a new anonymous root here. This is true regardless
444 // of the linkage of the callee because the aliasing "scope" is not just a
445 // property of the callee, but also all control dependencies in the caller.
446 MDNode *NewScope = MDB.createAnonymousAliasScope(NewDomain, Name);
447 NewScopes.insert(std::make_pair(A, NewScope));
450 // Iterate over all new instructions in the map; for all memory-access
451 // instructions, add the alias scope metadata.
452 for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
453 VMI != VMIE; ++VMI) {
454 if (const Instruction *I = dyn_cast<Instruction>(VMI->first)) {
458 Instruction *NI = dyn_cast<Instruction>(VMI->second);
462 bool IsArgMemOnlyCall = false, IsFuncCall = false;
463 SmallVector<const Value *, 2> PtrArgs;
465 if (const LoadInst *LI = dyn_cast<LoadInst>(I))
466 PtrArgs.push_back(LI->getPointerOperand());
467 else if (const StoreInst *SI = dyn_cast<StoreInst>(I))
468 PtrArgs.push_back(SI->getPointerOperand());
469 else if (const VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
470 PtrArgs.push_back(VAAI->getPointerOperand());
471 else if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I))
472 PtrArgs.push_back(CXI->getPointerOperand());
473 else if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I))
474 PtrArgs.push_back(RMWI->getPointerOperand());
475 else if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
476 // If we know that the call does not access memory, then we'll still
477 // know that about the inlined clone of this call site, and we don't
478 // need to add metadata.
479 if (ICS.doesNotAccessMemory())
484 AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(ICS);
485 if (MRB == AliasAnalysis::OnlyAccessesArgumentPointees ||
486 MRB == AliasAnalysis::OnlyReadsArgumentPointees)
487 IsArgMemOnlyCall = true;
490 for (ImmutableCallSite::arg_iterator AI = ICS.arg_begin(),
491 AE = ICS.arg_end(); AI != AE; ++AI) {
492 // We need to check the underlying objects of all arguments, not just
493 // the pointer arguments, because we might be passing pointers as
495 // However, if we know that the call only accesses pointer arguments,
496 // then we only need to check the pointer arguments.
497 if (IsArgMemOnlyCall && !(*AI)->getType()->isPointerTy())
500 PtrArgs.push_back(*AI);
504 // If we found no pointers, then this instruction is not suitable for
505 // pairing with an instruction to receive aliasing metadata.
506 // However, if this is a call, this we might just alias with none of the
507 // noalias arguments.
508 if (PtrArgs.empty() && !IsFuncCall)
511 // It is possible that there is only one underlying object, but you
512 // need to go through several PHIs to see it, and thus could be
513 // repeated in the Objects list.
514 SmallPtrSet<const Value *, 4> ObjSet;
515 SmallVector<Value *, 4> Scopes, NoAliases;
517 SmallSetVector<const Argument *, 4> NAPtrArgs;
518 for (unsigned i = 0, ie = PtrArgs.size(); i != ie; ++i) {
519 SmallVector<Value *, 4> Objects;
520 GetUnderlyingObjects(const_cast<Value*>(PtrArgs[i]),
521 Objects, DL, /* MaxLookup = */ 0);
523 for (Value *O : Objects)
527 // Figure out if we're derived from anything that is not a noalias
529 bool CanDeriveViaCapture = false, UsesAliasingPtr = false;
530 for (const Value *V : ObjSet) {
531 // Is this value a constant that cannot be derived from any pointer
532 // value (we need to exclude constant expressions, for example, that
533 // are formed from arithmetic on global symbols).
534 bool IsNonPtrConst = isa<ConstantInt>(V) || isa<ConstantFP>(V) ||
535 isa<ConstantPointerNull>(V) ||
536 isa<ConstantDataVector>(V) || isa<UndefValue>(V);
540 // If this is anything other than a noalias argument, then we cannot
541 // completely describe the aliasing properties using alias.scope
542 // metadata (and, thus, won't add any).
543 if (const Argument *A = dyn_cast<Argument>(V)) {
544 if (!A->hasNoAliasAttr())
545 UsesAliasingPtr = true;
547 UsesAliasingPtr = true;
550 // If this is not some identified function-local object (which cannot
551 // directly alias a noalias argument), or some other argument (which,
552 // by definition, also cannot alias a noalias argument), then we could
553 // alias a noalias argument that has been captured).
554 if (!isa<Argument>(V) &&
555 !isIdentifiedFunctionLocal(const_cast<Value*>(V)))
556 CanDeriveViaCapture = true;
559 // A function call can always get captured noalias pointers (via other
560 // parameters, globals, etc.).
561 if (IsFuncCall && !IsArgMemOnlyCall)
562 CanDeriveViaCapture = true;
564 // First, we want to figure out all of the sets with which we definitely
565 // don't alias. Iterate over all noalias set, and add those for which:
566 // 1. The noalias argument is not in the set of objects from which we
567 // definitely derive.
568 // 2. The noalias argument has not yet been captured.
569 // An arbitrary function that might load pointers could see captured
570 // noalias arguments via other noalias arguments or globals, and so we
571 // must always check for prior capture.
572 for (const Argument *A : NoAliasArgs) {
573 if (!ObjSet.count(A) && (!CanDeriveViaCapture ||
574 // It might be tempting to skip the
575 // PointerMayBeCapturedBefore check if
576 // A->hasNoCaptureAttr() is true, but this is
577 // incorrect because nocapture only guarantees
578 // that no copies outlive the function, not
579 // that the value cannot be locally captured.
580 !PointerMayBeCapturedBefore(A,
581 /* ReturnCaptures */ false,
582 /* StoreCaptures */ false, I, &DT)))
583 NoAliases.push_back(NewScopes[A]);
586 if (!NoAliases.empty())
587 NI->setMetadata(LLVMContext::MD_noalias, MDNode::concatenate(
588 NI->getMetadata(LLVMContext::MD_noalias),
589 MDNode::get(CalledFunc->getContext(), NoAliases)));
591 // Next, we want to figure out all of the sets to which we might belong.
592 // We might belong to a set if the noalias argument is in the set of
593 // underlying objects. If there is some non-noalias argument in our list
594 // of underlying objects, then we cannot add a scope because the fact
595 // that some access does not alias with any set of our noalias arguments
596 // cannot itself guarantee that it does not alias with this access
597 // (because there is some pointer of unknown origin involved and the
598 // other access might also depend on this pointer). We also cannot add
599 // scopes to arbitrary functions unless we know they don't access any
600 // non-parameter pointer-values.
601 bool CanAddScopes = !UsesAliasingPtr;
602 if (CanAddScopes && IsFuncCall)
603 CanAddScopes = IsArgMemOnlyCall;
606 for (const Argument *A : NoAliasArgs) {
608 Scopes.push_back(NewScopes[A]);
612 NI->setMetadata(LLVMContext::MD_alias_scope, MDNode::concatenate(
613 NI->getMetadata(LLVMContext::MD_alias_scope),
614 MDNode::get(CalledFunc->getContext(), Scopes)));
619 /// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
620 /// into the caller, update the specified callgraph to reflect the changes we
621 /// made. Note that it's possible that not all code was copied over, so only
622 /// some edges of the callgraph may remain.
623 static void UpdateCallGraphAfterInlining(CallSite CS,
624 Function::iterator FirstNewBlock,
625 ValueToValueMapTy &VMap,
626 InlineFunctionInfo &IFI) {
627 CallGraph &CG = *IFI.CG;
628 const Function *Caller = CS.getInstruction()->getParent()->getParent();
629 const Function *Callee = CS.getCalledFunction();
630 CallGraphNode *CalleeNode = CG[Callee];
631 CallGraphNode *CallerNode = CG[Caller];
633 // Since we inlined some uninlined call sites in the callee into the caller,
634 // add edges from the caller to all of the callees of the callee.
635 CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();
637 // Consider the case where CalleeNode == CallerNode.
638 CallGraphNode::CalledFunctionsVector CallCache;
639 if (CalleeNode == CallerNode) {
640 CallCache.assign(I, E);
641 I = CallCache.begin();
645 for (; I != E; ++I) {
646 const Value *OrigCall = I->first;
648 ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
649 // Only copy the edge if the call was inlined!
650 if (VMI == VMap.end() || VMI->second == nullptr)
653 // If the call was inlined, but then constant folded, there is no edge to
654 // add. Check for this case.
655 Instruction *NewCall = dyn_cast<Instruction>(VMI->second);
656 if (!NewCall) continue;
658 // Remember that this call site got inlined for the client of
660 IFI.InlinedCalls.push_back(NewCall);
662 // It's possible that inlining the callsite will cause it to go from an
663 // indirect to a direct call by resolving a function pointer. If this
664 // happens, set the callee of the new call site to a more precise
665 // destination. This can also happen if the call graph node of the caller
666 // was just unnecessarily imprecise.
667 if (!I->second->getFunction())
668 if (Function *F = CallSite(NewCall).getCalledFunction()) {
669 // Indirect call site resolved to direct call.
670 CallerNode->addCalledFunction(CallSite(NewCall), CG[F]);
675 CallerNode->addCalledFunction(CallSite(NewCall), I->second);
678 // Update the call graph by deleting the edge from Callee to Caller. We must
679 // do this after the loop above in case Caller and Callee are the same.
680 CallerNode->removeCallEdgeFor(CS);
683 static void HandleByValArgumentInit(Value *Dst, Value *Src, Module *M,
684 BasicBlock *InsertBlock,
685 InlineFunctionInfo &IFI) {
686 Type *AggTy = cast<PointerType>(Src->getType())->getElementType();
687 IRBuilder<> Builder(InsertBlock->begin());
690 if (IFI.DL == nullptr)
691 Size = ConstantExpr::getSizeOf(AggTy);
693 Size = Builder.getInt64(IFI.DL->getTypeStoreSize(AggTy));
695 // Always generate a memcpy of alignment 1 here because we don't know
696 // the alignment of the src pointer. Other optimizations can infer
698 Builder.CreateMemCpy(Dst, Src, Size, /*Align=*/1);
701 /// HandleByValArgument - When inlining a call site that has a byval argument,
702 /// we have to make the implicit memcpy explicit by adding it.
703 static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
704 const Function *CalledFunc,
705 InlineFunctionInfo &IFI,
706 unsigned ByValAlignment) {
707 PointerType *ArgTy = cast<PointerType>(Arg->getType());
708 Type *AggTy = ArgTy->getElementType();
710 // If the called function is readonly, then it could not mutate the caller's
711 // copy of the byval'd memory. In this case, it is safe to elide the copy and
713 if (CalledFunc->onlyReadsMemory()) {
714 // If the byval argument has a specified alignment that is greater than the
715 // passed in pointer, then we either have to round up the input pointer or
716 // give up on this transformation.
717 if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
720 // If the pointer is already known to be sufficiently aligned, or if we can
721 // round it up to a larger alignment, then we don't need a temporary.
722 if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
723 IFI.DL, IFI.AT, TheCall) >= ByValAlignment)
726 // Otherwise, we have to make a memcpy to get a safe alignment. This is bad
727 // for code quality, but rarely happens and is required for correctness.
730 // Create the alloca. If we have DataLayout, use nice alignment.
733 Align = IFI.DL->getPrefTypeAlignment(AggTy);
735 // If the byval had an alignment specified, we *must* use at least that
736 // alignment, as it is required by the byval argument (and uses of the
737 // pointer inside the callee).
738 Align = std::max(Align, ByValAlignment);
740 Function *Caller = TheCall->getParent()->getParent();
742 Value *NewAlloca = new AllocaInst(AggTy, nullptr, Align, Arg->getName(),
743 &*Caller->begin()->begin());
744 IFI.StaticAllocas.push_back(cast<AllocaInst>(NewAlloca));
746 // Uses of the argument in the function should use our new alloca
751 // isUsedByLifetimeMarker - Check whether this Value is used by a lifetime
753 static bool isUsedByLifetimeMarker(Value *V) {
754 for (User *U : V->users()) {
755 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {
756 switch (II->getIntrinsicID()) {
758 case Intrinsic::lifetime_start:
759 case Intrinsic::lifetime_end:
767 // hasLifetimeMarkers - Check whether the given alloca already has
768 // lifetime.start or lifetime.end intrinsics.
769 static bool hasLifetimeMarkers(AllocaInst *AI) {
770 Type *Ty = AI->getType();
771 Type *Int8PtrTy = Type::getInt8PtrTy(Ty->getContext(),
772 Ty->getPointerAddressSpace());
774 return isUsedByLifetimeMarker(AI);
776 // Do a scan to find all the casts to i8*.
777 for (User *U : AI->users()) {
778 if (U->getType() != Int8PtrTy) continue;
779 if (U->stripPointerCasts() != AI) continue;
780 if (isUsedByLifetimeMarker(U))
786 /// updateInlinedAtInfo - Helper function used by fixupLineNumbers to
787 /// recursively update InlinedAtEntry of a DebugLoc.
788 static DebugLoc updateInlinedAtInfo(const DebugLoc &DL,
789 const DebugLoc &InlinedAtDL,
791 if (MDNode *IA = DL.getInlinedAt(Ctx)) {
792 DebugLoc NewInlinedAtDL
793 = updateInlinedAtInfo(DebugLoc::getFromDILocation(IA), InlinedAtDL, Ctx);
794 return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
795 NewInlinedAtDL.getAsMDNode(Ctx));
798 return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
799 InlinedAtDL.getAsMDNode(Ctx));
802 /// fixupLineNumbers - Update inlined instructions' line numbers to
803 /// to encode location where these instructions are inlined.
804 static void fixupLineNumbers(Function *Fn, Function::iterator FI,
805 Instruction *TheCall) {
806 DebugLoc TheCallDL = TheCall->getDebugLoc();
807 if (TheCallDL.isUnknown())
810 for (; FI != Fn->end(); ++FI) {
811 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
813 DebugLoc DL = BI->getDebugLoc();
814 if (DL.isUnknown()) {
815 // If the inlined instruction has no line number, make it look as if it
816 // originates from the call location. This is important for
817 // ((__always_inline__, __nodebug__)) functions which must use caller
818 // location for all instructions in their function body.
819 BI->setDebugLoc(TheCallDL);
821 BI->setDebugLoc(updateInlinedAtInfo(DL, TheCallDL, BI->getContext()));
822 if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
823 LLVMContext &Ctx = BI->getContext();
824 MDNode *InlinedAt = BI->getDebugLoc().getInlinedAt(Ctx);
825 DVI->setOperand(2, createInlinedVariable(DVI->getVariable(),
833 /// InlineFunction - This function inlines the called function into the basic
834 /// block of the caller. This returns false if it is not possible to inline
835 /// this call. The program is still in a well defined state if this occurs
838 /// Note that this only does one level of inlining. For example, if the
839 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
840 /// exists in the instruction stream. Similarly this will inline a recursive
841 /// function by one level.
842 bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
843 bool InsertLifetime) {
844 Instruction *TheCall = CS.getInstruction();
845 assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
846 "Instruction not in function!");
848 // If IFI has any state in it, zap it before we fill it in.
851 const Function *CalledFunc = CS.getCalledFunction();
852 if (!CalledFunc || // Can't inline external function or indirect
853 CalledFunc->isDeclaration() || // call, or call to a vararg function!
854 CalledFunc->getFunctionType()->isVarArg()) return false;
856 // If the call to the callee cannot throw, set the 'nounwind' flag on any
857 // calls that we inline.
858 bool MarkNoUnwind = CS.doesNotThrow();
860 BasicBlock *OrigBB = TheCall->getParent();
861 Function *Caller = OrigBB->getParent();
863 // GC poses two hazards to inlining, which only occur when the callee has GC:
864 // 1. If the caller has no GC, then the callee's GC must be propagated to the
866 // 2. If the caller has a differing GC, it is invalid to inline.
867 if (CalledFunc->hasGC()) {
868 if (!Caller->hasGC())
869 Caller->setGC(CalledFunc->getGC());
870 else if (CalledFunc->getGC() != Caller->getGC())
874 // Get the personality function from the callee if it contains a landing pad.
875 Value *CalleePersonality = nullptr;
876 for (Function::const_iterator I = CalledFunc->begin(), E = CalledFunc->end();
878 if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
879 const BasicBlock *BB = II->getUnwindDest();
880 const LandingPadInst *LP = BB->getLandingPadInst();
881 CalleePersonality = LP->getPersonalityFn();
885 // Find the personality function used by the landing pads of the caller. If it
886 // exists, then check to see that it matches the personality function used in
888 if (CalleePersonality) {
889 for (Function::const_iterator I = Caller->begin(), E = Caller->end();
891 if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
892 const BasicBlock *BB = II->getUnwindDest();
893 const LandingPadInst *LP = BB->getLandingPadInst();
895 // If the personality functions match, then we can perform the
896 // inlining. Otherwise, we can't inline.
897 // TODO: This isn't 100% true. Some personality functions are proper
898 // supersets of others and can be used in place of the other.
899 if (LP->getPersonalityFn() != CalleePersonality)
906 // Get an iterator to the last basic block in the function, which will have
907 // the new function inlined after it.
908 Function::iterator LastBlock = &Caller->back();
910 // Make sure to capture all of the return instructions from the cloned
912 SmallVector<ReturnInst*, 8> Returns;
913 ClonedCodeInfo InlinedFunctionInfo;
914 Function::iterator FirstNewBlock;
916 { // Scope to destroy VMap after cloning.
917 ValueToValueMapTy VMap;
918 // Keep a list of pair (dst, src) to emit byval initializations.
919 SmallVector<std::pair<Value*, Value*>, 4> ByValInit;
921 assert(CalledFunc->arg_size() == CS.arg_size() &&
922 "No varargs calls can be inlined!");
924 // Calculate the vector of arguments to pass into the function cloner, which
925 // matches up the formal to the actual argument values.
926 CallSite::arg_iterator AI = CS.arg_begin();
928 for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
929 E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
930 Value *ActualArg = *AI;
932 // When byval arguments actually inlined, we need to make the copy implied
933 // by them explicit. However, we don't do this if the callee is readonly
934 // or readnone, because the copy would be unneeded: the callee doesn't
935 // modify the struct.
936 if (CS.isByValArgument(ArgNo)) {
937 ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
938 CalledFunc->getParamAlignment(ArgNo+1));
939 if (ActualArg != *AI)
940 ByValInit.push_back(std::make_pair(ActualArg, (Value*) *AI));
946 // We want the inliner to prune the code as it copies. We would LOVE to
947 // have no dead or constant instructions leftover after inlining occurs
948 // (which can happen, e.g., because an argument was constant), but we'll be
949 // happy with whatever the cloner can do.
950 CloneAndPruneFunctionInto(Caller, CalledFunc, VMap,
951 /*ModuleLevelChanges=*/false, Returns, ".i",
952 &InlinedFunctionInfo, IFI.DL, TheCall);
954 // Remember the first block that is newly cloned over.
955 FirstNewBlock = LastBlock; ++FirstNewBlock;
957 // Inject byval arguments initialization.
958 for (std::pair<Value*, Value*> &Init : ByValInit)
959 HandleByValArgumentInit(Init.first, Init.second, Caller->getParent(),
962 // Update the callgraph if requested.
964 UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
966 // Update inlined instructions' line number information.
967 fixupLineNumbers(Caller, FirstNewBlock, TheCall);
969 // Clone existing noalias metadata if necessary.
970 CloneAliasScopeMetadata(CS, VMap);
972 // Add noalias metadata if necessary.
973 AddAliasScopeMetadata(CS, VMap, IFI.DL, IFI.AA);
975 // FIXME: We could register any cloned assumptions instead of clearing the
976 // whole function's cache.
978 IFI.AT->forgetCachedAssumptions(Caller);
981 // If there are any alloca instructions in the block that used to be the entry
982 // block for the callee, move them to the entry block of the caller. First
983 // calculate which instruction they should be inserted before. We insert the
984 // instructions at the end of the current alloca list.
986 BasicBlock::iterator InsertPoint = Caller->begin()->begin();
987 for (BasicBlock::iterator I = FirstNewBlock->begin(),
988 E = FirstNewBlock->end(); I != E; ) {
989 AllocaInst *AI = dyn_cast<AllocaInst>(I++);
992 // If the alloca is now dead, remove it. This often occurs due to code
994 if (AI->use_empty()) {
995 AI->eraseFromParent();
999 if (!isa<Constant>(AI->getArraySize()))
1002 // Keep track of the static allocas that we inline into the caller.
1003 IFI.StaticAllocas.push_back(AI);
1005 // Scan for the block of allocas that we can move over, and move them
1007 while (isa<AllocaInst>(I) &&
1008 isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
1009 IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
1013 // Transfer all of the allocas over in a block. Using splice means
1014 // that the instructions aren't removed from the symbol table, then
1016 Caller->getEntryBlock().getInstList().splice(InsertPoint,
1017 FirstNewBlock->getInstList(),
1022 bool InlinedMustTailCalls = false;
1023 if (InlinedFunctionInfo.ContainsCalls) {
1024 CallInst::TailCallKind CallSiteTailKind = CallInst::TCK_None;
1025 if (CallInst *CI = dyn_cast<CallInst>(TheCall))
1026 CallSiteTailKind = CI->getTailCallKind();
1028 for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E;
1030 for (Instruction &I : *BB) {
1031 CallInst *CI = dyn_cast<CallInst>(&I);
1035 // We need to reduce the strength of any inlined tail calls. For
1036 // musttail, we have to avoid introducing potential unbounded stack
1037 // growth. For example, if functions 'f' and 'g' are mutually recursive
1038 // with musttail, we can inline 'g' into 'f' so long as we preserve
1039 // musttail on the cloned call to 'f'. If either the inlined call site
1040 // or the cloned call site is *not* musttail, the program already has
1041 // one frame of stack growth, so it's safe to remove musttail. Here is
1042 // a table of example transformations:
1044 // f -> musttail g -> musttail f ==> f -> musttail f
1045 // f -> musttail g -> tail f ==> f -> tail f
1046 // f -> g -> musttail f ==> f -> f
1047 // f -> g -> tail f ==> f -> f
1048 CallInst::TailCallKind ChildTCK = CI->getTailCallKind();
1049 ChildTCK = std::min(CallSiteTailKind, ChildTCK);
1050 CI->setTailCallKind(ChildTCK);
1051 InlinedMustTailCalls |= CI->isMustTailCall();
1053 // Calls inlined through a 'nounwind' call site should be marked
1056 CI->setDoesNotThrow();
1061 // Leave lifetime markers for the static alloca's, scoping them to the
1062 // function we just inlined.
1063 if (InsertLifetime && !IFI.StaticAllocas.empty()) {
1064 IRBuilder<> builder(FirstNewBlock->begin());
1065 for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
1066 AllocaInst *AI = IFI.StaticAllocas[ai];
1068 // If the alloca is already scoped to something smaller than the whole
1069 // function then there's no need to add redundant, less accurate markers.
1070 if (hasLifetimeMarkers(AI))
1073 // Try to determine the size of the allocation.
1074 ConstantInt *AllocaSize = nullptr;
1075 if (ConstantInt *AIArraySize =
1076 dyn_cast<ConstantInt>(AI->getArraySize())) {
1078 Type *AllocaType = AI->getAllocatedType();
1079 uint64_t AllocaTypeSize = IFI.DL->getTypeAllocSize(AllocaType);
1080 uint64_t AllocaArraySize = AIArraySize->getLimitedValue();
1081 assert(AllocaArraySize > 0 && "array size of AllocaInst is zero");
1082 // Check that array size doesn't saturate uint64_t and doesn't
1083 // overflow when it's multiplied by type size.
1084 if (AllocaArraySize != ~0ULL &&
1085 UINT64_MAX / AllocaArraySize >= AllocaTypeSize) {
1086 AllocaSize = ConstantInt::get(Type::getInt64Ty(AI->getContext()),
1087 AllocaArraySize * AllocaTypeSize);
1092 builder.CreateLifetimeStart(AI, AllocaSize);
1093 for (ReturnInst *RI : Returns) {
1094 // Don't insert llvm.lifetime.end calls between a musttail call and a
1095 // return. The return kills all local allocas.
1096 if (InlinedMustTailCalls &&
1097 RI->getParent()->getTerminatingMustTailCall())
1099 IRBuilder<>(RI).CreateLifetimeEnd(AI, AllocaSize);
1104 // If the inlined code contained dynamic alloca instructions, wrap the inlined
1105 // code with llvm.stacksave/llvm.stackrestore intrinsics.
1106 if (InlinedFunctionInfo.ContainsDynamicAllocas) {
1107 Module *M = Caller->getParent();
1108 // Get the two intrinsics we care about.
1109 Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
1110 Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);
1112 // Insert the llvm.stacksave.
1113 CallInst *SavedPtr = IRBuilder<>(FirstNewBlock, FirstNewBlock->begin())
1114 .CreateCall(StackSave, "savedstack");
1116 // Insert a call to llvm.stackrestore before any return instructions in the
1117 // inlined function.
1118 for (ReturnInst *RI : Returns) {
1119 // Don't insert llvm.stackrestore calls between a musttail call and a
1120 // return. The return will restore the stack pointer.
1121 if (InlinedMustTailCalls && RI->getParent()->getTerminatingMustTailCall())
1123 IRBuilder<>(RI).CreateCall(StackRestore, SavedPtr);
1127 // If we are inlining for an invoke instruction, we must make sure to rewrite
1128 // any call instructions into invoke instructions.
1129 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
1130 HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);
1132 // Handle any inlined musttail call sites. In order for a new call site to be
1133 // musttail, the source of the clone and the inlined call site must have been
1134 // musttail. Therefore it's safe to return without merging control into the
1136 if (InlinedMustTailCalls) {
1137 // Check if we need to bitcast the result of any musttail calls.
1138 Type *NewRetTy = Caller->getReturnType();
1139 bool NeedBitCast = !TheCall->use_empty() && TheCall->getType() != NewRetTy;
1141 // Handle the returns preceded by musttail calls separately.
1142 SmallVector<ReturnInst *, 8> NormalReturns;
1143 for (ReturnInst *RI : Returns) {
1144 CallInst *ReturnedMustTail =
1145 RI->getParent()->getTerminatingMustTailCall();
1146 if (!ReturnedMustTail) {
1147 NormalReturns.push_back(RI);
1153 // Delete the old return and any preceding bitcast.
1154 BasicBlock *CurBB = RI->getParent();
1155 auto *OldCast = dyn_cast_or_null<BitCastInst>(RI->getReturnValue());
1156 RI->eraseFromParent();
1158 OldCast->eraseFromParent();
1160 // Insert a new bitcast and return with the right type.
1161 IRBuilder<> Builder(CurBB);
1162 Builder.CreateRet(Builder.CreateBitCast(ReturnedMustTail, NewRetTy));
1165 // Leave behind the normal returns so we can merge control flow.
1166 std::swap(Returns, NormalReturns);
1169 // If we cloned in _exactly one_ basic block, and if that block ends in a
1170 // return instruction, we splice the body of the inlined callee directly into
1171 // the calling basic block.
1172 if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
1173 // Move all of the instructions right before the call.
1174 OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(),
1175 FirstNewBlock->begin(), FirstNewBlock->end());
1176 // Remove the cloned basic block.
1177 Caller->getBasicBlockList().pop_back();
1179 // If the call site was an invoke instruction, add a branch to the normal
1181 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
1182 BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall);
1183 NewBr->setDebugLoc(Returns[0]->getDebugLoc());
1186 // If the return instruction returned a value, replace uses of the call with
1187 // uses of the returned value.
1188 if (!TheCall->use_empty()) {
1189 ReturnInst *R = Returns[0];
1190 if (TheCall == R->getReturnValue())
1191 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
1193 TheCall->replaceAllUsesWith(R->getReturnValue());
1195 // Since we are now done with the Call/Invoke, we can delete it.
1196 TheCall->eraseFromParent();
1198 // Since we are now done with the return instruction, delete it also.
1199 Returns[0]->eraseFromParent();
1201 // We are now done with the inlining.
1205 // Otherwise, we have the normal case, of more than one block to inline or
1206 // multiple return sites.
1208 // We want to clone the entire callee function into the hole between the
1209 // "starter" and "ender" blocks. How we accomplish this depends on whether
1210 // this is an invoke instruction or a call instruction.
1211 BasicBlock *AfterCallBB;
1212 BranchInst *CreatedBranchToNormalDest = nullptr;
1213 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
1215 // Add an unconditional branch to make this look like the CallInst case...
1216 CreatedBranchToNormalDest = BranchInst::Create(II->getNormalDest(), TheCall);
1218 // Split the basic block. This guarantees that no PHI nodes will have to be
1219 // updated due to new incoming edges, and make the invoke case more
1220 // symmetric to the call case.
1221 AfterCallBB = OrigBB->splitBasicBlock(CreatedBranchToNormalDest,
1222 CalledFunc->getName()+".exit");
1224 } else { // It's a call
1225 // If this is a call instruction, we need to split the basic block that
1226 // the call lives in.
1228 AfterCallBB = OrigBB->splitBasicBlock(TheCall,
1229 CalledFunc->getName()+".exit");
1232 // Change the branch that used to go to AfterCallBB to branch to the first
1233 // basic block of the inlined function.
1235 TerminatorInst *Br = OrigBB->getTerminator();
1236 assert(Br && Br->getOpcode() == Instruction::Br &&
1237 "splitBasicBlock broken!");
1238 Br->setOperand(0, FirstNewBlock);
1241 // Now that the function is correct, make it a little bit nicer. In
1242 // particular, move the basic blocks inserted from the end of the function
1243 // into the space made by splitting the source basic block.
1244 Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
1245 FirstNewBlock, Caller->end());
1247 // Handle all of the return instructions that we just cloned in, and eliminate
1248 // any users of the original call/invoke instruction.
1249 Type *RTy = CalledFunc->getReturnType();
1251 PHINode *PHI = nullptr;
1252 if (Returns.size() > 1) {
1253 // The PHI node should go at the front of the new basic block to merge all
1254 // possible incoming values.
1255 if (!TheCall->use_empty()) {
1256 PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
1257 AfterCallBB->begin());
1258 // Anything that used the result of the function call should now use the
1259 // PHI node as their operand.
1260 TheCall->replaceAllUsesWith(PHI);
1263 // Loop over all of the return instructions adding entries to the PHI node
1266 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
1267 ReturnInst *RI = Returns[i];
1268 assert(RI->getReturnValue()->getType() == PHI->getType() &&
1269 "Ret value not consistent in function!");
1270 PHI->addIncoming(RI->getReturnValue(), RI->getParent());
1275 // Add a branch to the merge points and remove return instructions.
1277 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
1278 ReturnInst *RI = Returns[i];
1279 BranchInst* BI = BranchInst::Create(AfterCallBB, RI);
1280 Loc = RI->getDebugLoc();
1281 BI->setDebugLoc(Loc);
1282 RI->eraseFromParent();
1284 // We need to set the debug location to *somewhere* inside the
1285 // inlined function. The line number may be nonsensical, but the
1286 // instruction will at least be associated with the right
1288 if (CreatedBranchToNormalDest)
1289 CreatedBranchToNormalDest->setDebugLoc(Loc);
1290 } else if (!Returns.empty()) {
1291 // Otherwise, if there is exactly one return value, just replace anything
1292 // using the return value of the call with the computed value.
1293 if (!TheCall->use_empty()) {
1294 if (TheCall == Returns[0]->getReturnValue())
1295 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
1297 TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
1300 // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
1301 BasicBlock *ReturnBB = Returns[0]->getParent();
1302 ReturnBB->replaceAllUsesWith(AfterCallBB);
1304 // Splice the code from the return block into the block that it will return
1305 // to, which contains the code that was after the call.
1306 AfterCallBB->getInstList().splice(AfterCallBB->begin(),
1307 ReturnBB->getInstList());
1309 if (CreatedBranchToNormalDest)
1310 CreatedBranchToNormalDest->setDebugLoc(Returns[0]->getDebugLoc());
1312 // Delete the return instruction now and empty ReturnBB now.
1313 Returns[0]->eraseFromParent();
1314 ReturnBB->eraseFromParent();
1315 } else if (!TheCall->use_empty()) {
1316 // No returns, but something is using the return value of the call. Just
1318 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
1321 // Since we are now done with the Call/Invoke, we can delete it.
1322 TheCall->eraseFromParent();
1324 // If we inlined any musttail calls and the original return is now
1325 // unreachable, delete it. It can only contain a bitcast and ret.
1326 if (InlinedMustTailCalls && pred_begin(AfterCallBB) == pred_end(AfterCallBB))
1327 AfterCallBB->eraseFromParent();
1329 // We should always be able to fold the entry block of the function into the
1330 // single predecessor of the block...
1331 assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
1332 BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);
1334 // Splice the code entry block into calling block, right before the
1335 // unconditional branch.
1336 CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
1337 OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
1339 // Remove the unconditional branch.
1340 OrigBB->getInstList().erase(Br);
1342 // Now we can remove the CalleeEntry block, which is now empty.
1343 Caller->getBasicBlockList().erase(CalleeEntry);
1345 // If we inserted a phi node, check to see if it has a single value (e.g. all
1346 // the entries are the same or undef). If so, remove the PHI so it doesn't
1347 // block other optimizations.
1349 if (Value *V = SimplifyInstruction(PHI, IFI.DL, nullptr, nullptr, IFI.AT)) {
1350 PHI->replaceAllUsesWith(V);
1351 PHI->eraseFromParent();