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/SmallVector.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/Analysis/CallGraph.h"
19 #include "llvm/Analysis/InstructionSimplify.h"
20 #include "llvm/DebugInfo.h"
21 #include "llvm/IR/Attributes.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DataLayout.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/IRBuilder.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/IR/Intrinsics.h"
29 #include "llvm/IR/Module.h"
30 #include "llvm/Support/CallSite.h"
31 #include "llvm/Transforms/Utils/Local.h"
34 bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
35 bool InsertLifetime) {
36 return InlineFunction(CallSite(CI), IFI, InsertLifetime);
38 bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI,
39 bool InsertLifetime) {
40 return InlineFunction(CallSite(II), IFI, InsertLifetime);
44 /// A class for recording information about inlining through an invoke.
45 class InvokeInliningInfo {
46 BasicBlock *OuterResumeDest; ///< Destination of the invoke's unwind.
47 BasicBlock *InnerResumeDest; ///< Destination for the callee's resume.
48 LandingPadInst *CallerLPad; ///< LandingPadInst associated with the invoke.
49 PHINode *InnerEHValuesPHI; ///< PHI for EH values from landingpad insts.
50 SmallVector<Value*, 8> UnwindDestPHIValues;
53 InvokeInliningInfo(InvokeInst *II)
54 : OuterResumeDest(II->getUnwindDest()), InnerResumeDest(0),
55 CallerLPad(0), InnerEHValuesPHI(0) {
56 // If there are PHI nodes in the unwind destination block, we need to keep
57 // track of which values came into them from the invoke before removing
58 // the edge from this block.
59 llvm::BasicBlock *InvokeBB = II->getParent();
60 BasicBlock::iterator I = OuterResumeDest->begin();
61 for (; isa<PHINode>(I); ++I) {
62 // Save the value to use for this edge.
63 PHINode *PHI = cast<PHINode>(I);
64 UnwindDestPHIValues.push_back(PHI->getIncomingValueForBlock(InvokeBB));
67 CallerLPad = cast<LandingPadInst>(I);
70 /// getOuterResumeDest - The outer unwind destination is the target of
71 /// unwind edges introduced for calls within the inlined function.
72 BasicBlock *getOuterResumeDest() const {
73 return OuterResumeDest;
76 BasicBlock *getInnerResumeDest();
78 LandingPadInst *getLandingPadInst() const { return CallerLPad; }
80 /// forwardResume - Forward the 'resume' instruction to the caller's landing
81 /// pad block. When the landing pad block has only one predecessor, this is
82 /// a simple branch. When there is more than one predecessor, we need to
83 /// split the landing pad block after the landingpad instruction and jump
85 void forwardResume(ResumeInst *RI, BasicBlock *FirstNewBlock);
87 /// addIncomingPHIValuesFor - Add incoming-PHI values to the unwind
88 /// destination block for the given basic block, using the values for the
89 /// original invoke's source block.
90 void addIncomingPHIValuesFor(BasicBlock *BB) const {
91 addIncomingPHIValuesForInto(BB, OuterResumeDest);
94 void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
95 BasicBlock::iterator I = dest->begin();
96 for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
97 PHINode *phi = cast<PHINode>(I);
98 phi->addIncoming(UnwindDestPHIValues[i], src);
104 /// getInnerResumeDest - Get or create a target for the branch from ResumeInsts.
105 BasicBlock *InvokeInliningInfo::getInnerResumeDest() {
106 if (InnerResumeDest) return InnerResumeDest;
108 // Split the landing pad.
109 BasicBlock::iterator SplitPoint = CallerLPad; ++SplitPoint;
111 OuterResumeDest->splitBasicBlock(SplitPoint,
112 OuterResumeDest->getName() + ".body");
114 // The number of incoming edges we expect to the inner landing pad.
115 const unsigned PHICapacity = 2;
117 // Create corresponding new PHIs for all the PHIs in the outer landing pad.
118 BasicBlock::iterator InsertPoint = InnerResumeDest->begin();
119 BasicBlock::iterator I = OuterResumeDest->begin();
120 for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
121 PHINode *OuterPHI = cast<PHINode>(I);
122 PHINode *InnerPHI = PHINode::Create(OuterPHI->getType(), PHICapacity,
123 OuterPHI->getName() + ".lpad-body",
125 OuterPHI->replaceAllUsesWith(InnerPHI);
126 InnerPHI->addIncoming(OuterPHI, OuterResumeDest);
129 // Create a PHI for the exception values.
130 InnerEHValuesPHI = PHINode::Create(CallerLPad->getType(), PHICapacity,
131 "eh.lpad-body", InsertPoint);
132 CallerLPad->replaceAllUsesWith(InnerEHValuesPHI);
133 InnerEHValuesPHI->addIncoming(CallerLPad, OuterResumeDest);
136 return InnerResumeDest;
139 /// forwardResume - Forward the 'resume' instruction to the caller's landing pad
140 /// block. When the landing pad block has only one predecessor, this is a simple
141 /// branch. When there is more than one predecessor, we need to split the
142 /// landing pad block after the landingpad instruction and jump to there.
143 void InvokeInliningInfo::forwardResume(ResumeInst *RI,
144 BasicBlock *FirstNewBlock) {
145 BasicBlock *Dest = getInnerResumeDest();
146 LandingPadInst *OuterLPad = getLandingPadInst();
147 BasicBlock *Src = RI->getParent();
149 BranchInst::Create(Dest, Src);
151 // Update the PHIs in the destination. They were inserted in an order which
153 addIncomingPHIValuesForInto(Src, Dest);
155 InnerEHValuesPHI->addIncoming(RI->getOperand(0), Src);
156 RI->eraseFromParent();
158 // Get all of the inlined landing pad instructions.
159 SmallPtrSet<LandingPadInst*, 16> InlinedLPads;
160 Function *Caller = FirstNewBlock->getParent();
161 for (Function::iterator I = FirstNewBlock, E = Caller->end(); I != E; ++I)
162 if (InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
163 LandingPadInst *LPI = II->getLandingPadInst();
164 if (!LPI->hasCatchAll())
165 InlinedLPads.insert(LPI);
168 // Merge the catch clauses from the outer landing pad instruction into the
169 // inlined landing pad instructions.
170 for (SmallPtrSet<LandingPadInst*, 16>::iterator I = InlinedLPads.begin(),
171 E = InlinedLPads.end(); I != E; ++I) {
172 LandingPadInst *InlinedLPad = *I;
173 for (unsigned OuterIdx = 0, OuterNum = OuterLPad->getNumClauses();
174 OuterIdx != OuterNum; ++OuterIdx) {
175 bool hasClause = false;
176 if (OuterLPad->isFilter(OuterIdx)) continue;
177 Value *OuterClause = OuterLPad->getClause(OuterIdx);
178 for (unsigned Idx = 0, N = InlinedLPad->getNumClauses(); Idx != N; ++Idx)
179 if (OuterClause == InlinedLPad->getClause(Idx)) {
184 InlinedLPad->addClause(OuterClause);
189 /// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
190 /// an invoke, we have to turn all of the calls that can throw into
191 /// invokes. This function analyze BB to see if there are any calls, and if so,
192 /// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
193 /// nodes in that block with the values specified in InvokeDestPHIValues.
195 /// Returns true to indicate that the next block should be skipped.
196 static bool HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
197 InvokeInliningInfo &Invoke) {
198 LandingPadInst *LPI = Invoke.getLandingPadInst();
200 for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
201 Instruction *I = BBI++;
203 if (LandingPadInst *L = dyn_cast<LandingPadInst>(I)) {
204 unsigned NumClauses = LPI->getNumClauses();
205 L->reserveClauses(NumClauses);
206 for (unsigned i = 0; i != NumClauses; ++i)
207 L->addClause(LPI->getClause(i));
210 // We only need to check for function calls: inlined invoke
211 // instructions require no special handling.
212 CallInst *CI = dyn_cast<CallInst>(I);
214 // If this call cannot unwind, don't convert it to an invoke.
215 if (!CI || CI->doesNotThrow())
218 // Convert this function call into an invoke instruction. First, split the
220 BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
222 // Delete the unconditional branch inserted by splitBasicBlock
223 BB->getInstList().pop_back();
225 // Create the new invoke instruction.
226 ImmutableCallSite CS(CI);
227 SmallVector<Value*, 8> InvokeArgs(CS.arg_begin(), CS.arg_end());
228 InvokeInst *II = InvokeInst::Create(CI->getCalledValue(), Split,
229 Invoke.getOuterResumeDest(),
230 InvokeArgs, CI->getName(), BB);
231 II->setCallingConv(CI->getCallingConv());
232 II->setAttributes(CI->getAttributes());
234 // Make sure that anything using the call now uses the invoke! This also
235 // updates the CallGraph if present, because it uses a WeakVH.
236 CI->replaceAllUsesWith(II);
238 // Delete the original call
239 Split->getInstList().pop_front();
241 // Update any PHI nodes in the exceptional block to indicate that there is
242 // now a new entry in them.
243 Invoke.addIncomingPHIValuesFor(BB);
250 /// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
251 /// in the body of the inlined function into invokes.
253 /// II is the invoke instruction being inlined. FirstNewBlock is the first
254 /// block of the inlined code (the last block is the end of the function),
255 /// and InlineCodeInfo is information about the code that got inlined.
256 static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
257 ClonedCodeInfo &InlinedCodeInfo) {
258 BasicBlock *InvokeDest = II->getUnwindDest();
260 Function *Caller = FirstNewBlock->getParent();
262 // The inlined code is currently at the end of the function, scan from the
263 // start of the inlined code to its end, checking for stuff we need to
265 InvokeInliningInfo Invoke(II);
267 for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB){
268 if (InlinedCodeInfo.ContainsCalls)
269 if (HandleCallsInBlockInlinedThroughInvoke(BB, Invoke)) {
270 // Honor a request to skip the next block.
275 // Forward any resumes that are remaining here.
276 if (ResumeInst *RI = dyn_cast<ResumeInst>(BB->getTerminator()))
277 Invoke.forwardResume(RI, FirstNewBlock);
280 // Now that everything is happy, we have one final detail. The PHI nodes in
281 // the exception destination block still have entries due to the original
282 // invoke instruction. Eliminate these entries (which might even delete the
284 InvokeDest->removePredecessor(II->getParent());
287 /// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
288 /// into the caller, update the specified callgraph to reflect the changes we
289 /// made. Note that it's possible that not all code was copied over, so only
290 /// some edges of the callgraph may remain.
291 static void UpdateCallGraphAfterInlining(CallSite CS,
292 Function::iterator FirstNewBlock,
293 ValueToValueMapTy &VMap,
294 InlineFunctionInfo &IFI) {
295 CallGraph &CG = *IFI.CG;
296 const Function *Caller = CS.getInstruction()->getParent()->getParent();
297 const Function *Callee = CS.getCalledFunction();
298 CallGraphNode *CalleeNode = CG[Callee];
299 CallGraphNode *CallerNode = CG[Caller];
301 // Since we inlined some uninlined call sites in the callee into the caller,
302 // add edges from the caller to all of the callees of the callee.
303 CallGraphNode::iterator I = CalleeNode->begin(), E = CalleeNode->end();
305 // Consider the case where CalleeNode == CallerNode.
306 CallGraphNode::CalledFunctionsVector CallCache;
307 if (CalleeNode == CallerNode) {
308 CallCache.assign(I, E);
309 I = CallCache.begin();
313 for (; I != E; ++I) {
314 const Value *OrigCall = I->first;
316 ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
317 // Only copy the edge if the call was inlined!
318 if (VMI == VMap.end() || VMI->second == 0)
321 // If the call was inlined, but then constant folded, there is no edge to
322 // add. Check for this case.
323 Instruction *NewCall = dyn_cast<Instruction>(VMI->second);
324 if (NewCall == 0) continue;
326 // Remember that this call site got inlined for the client of
328 IFI.InlinedCalls.push_back(NewCall);
330 // It's possible that inlining the callsite will cause it to go from an
331 // indirect to a direct call by resolving a function pointer. If this
332 // happens, set the callee of the new call site to a more precise
333 // destination. This can also happen if the call graph node of the caller
334 // was just unnecessarily imprecise.
335 if (I->second->getFunction() == 0)
336 if (Function *F = CallSite(NewCall).getCalledFunction()) {
337 // Indirect call site resolved to direct call.
338 CallerNode->addCalledFunction(CallSite(NewCall), CG[F]);
343 CallerNode->addCalledFunction(CallSite(NewCall), I->second);
346 // Update the call graph by deleting the edge from Callee to Caller. We must
347 // do this after the loop above in case Caller and Callee are the same.
348 CallerNode->removeCallEdgeFor(CS);
351 /// HandleByValArgument - When inlining a call site that has a byval argument,
352 /// we have to make the implicit memcpy explicit by adding it.
353 static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
354 const Function *CalledFunc,
355 InlineFunctionInfo &IFI,
356 unsigned ByValAlignment) {
357 Type *AggTy = cast<PointerType>(Arg->getType())->getElementType();
359 // If the called function is readonly, then it could not mutate the caller's
360 // copy of the byval'd memory. In this case, it is safe to elide the copy and
362 if (CalledFunc->onlyReadsMemory()) {
363 // If the byval argument has a specified alignment that is greater than the
364 // passed in pointer, then we either have to round up the input pointer or
365 // give up on this transformation.
366 if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
369 // If the pointer is already known to be sufficiently aligned, or if we can
370 // round it up to a larger alignment, then we don't need a temporary.
371 if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
372 IFI.TD) >= ByValAlignment)
375 // Otherwise, we have to make a memcpy to get a safe alignment. This is bad
376 // for code quality, but rarely happens and is required for correctness.
379 LLVMContext &Context = Arg->getContext();
381 Type *VoidPtrTy = Type::getInt8PtrTy(Context);
383 // Create the alloca. If we have DataLayout, use nice alignment.
386 Align = IFI.TD->getPrefTypeAlignment(AggTy);
388 // If the byval had an alignment specified, we *must* use at least that
389 // alignment, as it is required by the byval argument (and uses of the
390 // pointer inside the callee).
391 Align = std::max(Align, ByValAlignment);
393 Function *Caller = TheCall->getParent()->getParent();
395 Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(),
396 &*Caller->begin()->begin());
398 Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
399 Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
402 Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
403 Value *SrcCast = new BitCastInst(Arg, VoidPtrTy, "tmp", TheCall);
407 Size = ConstantExpr::getSizeOf(AggTy);
409 Size = ConstantInt::get(Type::getInt64Ty(Context),
410 IFI.TD->getTypeStoreSize(AggTy));
412 // Always generate a memcpy of alignment 1 here because we don't know
413 // the alignment of the src pointer. Other optimizations can infer
415 Value *CallArgs[] = {
416 DestCast, SrcCast, Size,
417 ConstantInt::get(Type::getInt32Ty(Context), 1),
418 ConstantInt::getFalse(Context) // isVolatile
420 IRBuilder<>(TheCall).CreateCall(MemCpyFn, CallArgs);
422 // Uses of the argument in the function should use our new alloca
427 // isUsedByLifetimeMarker - Check whether this Value is used by a lifetime
429 static bool isUsedByLifetimeMarker(Value *V) {
430 for (Value::use_iterator UI = V->use_begin(), UE = V->use_end(); UI != UE;
432 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*UI)) {
433 switch (II->getIntrinsicID()) {
435 case Intrinsic::lifetime_start:
436 case Intrinsic::lifetime_end:
444 // hasLifetimeMarkers - Check whether the given alloca already has
445 // lifetime.start or lifetime.end intrinsics.
446 static bool hasLifetimeMarkers(AllocaInst *AI) {
447 Type *Int8PtrTy = Type::getInt8PtrTy(AI->getType()->getContext());
448 if (AI->getType() == Int8PtrTy)
449 return isUsedByLifetimeMarker(AI);
451 // Do a scan to find all the casts to i8*.
452 for (Value::use_iterator I = AI->use_begin(), E = AI->use_end(); I != E;
454 if (I->getType() != Int8PtrTy) continue;
455 if (I->stripPointerCasts() != AI) continue;
456 if (isUsedByLifetimeMarker(*I))
462 /// updateInlinedAtInfo - Helper function used by fixupLineNumbers to
463 /// recursively update InlinedAtEntry of a DebugLoc.
464 static DebugLoc updateInlinedAtInfo(const DebugLoc &DL,
465 const DebugLoc &InlinedAtDL,
467 if (MDNode *IA = DL.getInlinedAt(Ctx)) {
468 DebugLoc NewInlinedAtDL
469 = updateInlinedAtInfo(DebugLoc::getFromDILocation(IA), InlinedAtDL, Ctx);
470 return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
471 NewInlinedAtDL.getAsMDNode(Ctx));
474 return DebugLoc::get(DL.getLine(), DL.getCol(), DL.getScope(Ctx),
475 InlinedAtDL.getAsMDNode(Ctx));
478 /// fixupLineNumbers - Update inlined instructions' line numbers to
479 /// to encode location where these instructions are inlined.
480 static void fixupLineNumbers(Function *Fn, Function::iterator FI,
481 Instruction *TheCall) {
482 DebugLoc TheCallDL = TheCall->getDebugLoc();
483 if (TheCallDL.isUnknown())
486 for (; FI != Fn->end(); ++FI) {
487 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
489 DebugLoc DL = BI->getDebugLoc();
490 if (!DL.isUnknown()) {
491 BI->setDebugLoc(updateInlinedAtInfo(DL, TheCallDL, BI->getContext()));
492 if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
493 LLVMContext &Ctx = BI->getContext();
494 MDNode *InlinedAt = BI->getDebugLoc().getInlinedAt(Ctx);
495 DVI->setOperand(2, createInlinedVariable(DVI->getVariable(),
503 /// InlineFunction - This function inlines the called function into the basic
504 /// block of the caller. This returns false if it is not possible to inline
505 /// this call. The program is still in a well defined state if this occurs
508 /// Note that this only does one level of inlining. For example, if the
509 /// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
510 /// exists in the instruction stream. Similarly this will inline a recursive
511 /// function by one level.
512 bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
513 bool InsertLifetime) {
514 Instruction *TheCall = CS.getInstruction();
515 assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
516 "Instruction not in function!");
518 // If IFI has any state in it, zap it before we fill it in.
521 const Function *CalledFunc = CS.getCalledFunction();
522 if (CalledFunc == 0 || // Can't inline external function or indirect
523 CalledFunc->isDeclaration() || // call, or call to a vararg function!
524 CalledFunc->getFunctionType()->isVarArg()) return false;
526 // If the call to the callee is not a tail call, we must clear the 'tail'
527 // flags on any calls that we inline.
528 bool MustClearTailCallFlags =
529 !(isa<CallInst>(TheCall) && cast<CallInst>(TheCall)->isTailCall());
531 // If the call to the callee cannot throw, set the 'nounwind' flag on any
532 // calls that we inline.
533 bool MarkNoUnwind = CS.doesNotThrow();
535 BasicBlock *OrigBB = TheCall->getParent();
536 Function *Caller = OrigBB->getParent();
538 // GC poses two hazards to inlining, which only occur when the callee has GC:
539 // 1. If the caller has no GC, then the callee's GC must be propagated to the
541 // 2. If the caller has a differing GC, it is invalid to inline.
542 if (CalledFunc->hasGC()) {
543 if (!Caller->hasGC())
544 Caller->setGC(CalledFunc->getGC());
545 else if (CalledFunc->getGC() != Caller->getGC())
549 // Get the personality function from the callee if it contains a landing pad.
550 Value *CalleePersonality = 0;
551 for (Function::const_iterator I = CalledFunc->begin(), E = CalledFunc->end();
553 if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
554 const BasicBlock *BB = II->getUnwindDest();
555 const LandingPadInst *LP = BB->getLandingPadInst();
556 CalleePersonality = LP->getPersonalityFn();
560 // Find the personality function used by the landing pads of the caller. If it
561 // exists, then check to see that it matches the personality function used in
563 if (CalleePersonality) {
564 for (Function::const_iterator I = Caller->begin(), E = Caller->end();
566 if (const InvokeInst *II = dyn_cast<InvokeInst>(I->getTerminator())) {
567 const BasicBlock *BB = II->getUnwindDest();
568 const LandingPadInst *LP = BB->getLandingPadInst();
570 // If the personality functions match, then we can perform the
571 // inlining. Otherwise, we can't inline.
572 // TODO: This isn't 100% true. Some personality functions are proper
573 // supersets of others and can be used in place of the other.
574 if (LP->getPersonalityFn() != CalleePersonality)
581 // Get an iterator to the last basic block in the function, which will have
582 // the new function inlined after it.
583 Function::iterator LastBlock = &Caller->back();
585 // Make sure to capture all of the return instructions from the cloned
587 SmallVector<ReturnInst*, 8> Returns;
588 ClonedCodeInfo InlinedFunctionInfo;
589 Function::iterator FirstNewBlock;
591 { // Scope to destroy VMap after cloning.
592 ValueToValueMapTy VMap;
594 assert(CalledFunc->arg_size() == CS.arg_size() &&
595 "No varargs calls can be inlined!");
597 // Calculate the vector of arguments to pass into the function cloner, which
598 // matches up the formal to the actual argument values.
599 CallSite::arg_iterator AI = CS.arg_begin();
601 for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
602 E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
603 Value *ActualArg = *AI;
605 // When byval arguments actually inlined, we need to make the copy implied
606 // by them explicit. However, we don't do this if the callee is readonly
607 // or readnone, because the copy would be unneeded: the callee doesn't
608 // modify the struct.
609 if (CS.isByValArgument(ArgNo)) {
610 ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
611 CalledFunc->getParamAlignment(ArgNo+1));
613 // Calls that we inline may use the new alloca, so we need to clear
614 // their 'tail' flags if HandleByValArgument introduced a new alloca and
615 // the callee has calls.
616 MustClearTailCallFlags |= ActualArg != *AI;
622 // We want the inliner to prune the code as it copies. We would LOVE to
623 // have no dead or constant instructions leftover after inlining occurs
624 // (which can happen, e.g., because an argument was constant), but we'll be
625 // happy with whatever the cloner can do.
626 CloneAndPruneFunctionInto(Caller, CalledFunc, VMap,
627 /*ModuleLevelChanges=*/false, Returns, ".i",
628 &InlinedFunctionInfo, IFI.TD, TheCall);
630 // Remember the first block that is newly cloned over.
631 FirstNewBlock = LastBlock; ++FirstNewBlock;
633 // Update the callgraph if requested.
635 UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
637 // Update inlined instructions' line number information.
638 fixupLineNumbers(Caller, FirstNewBlock, TheCall);
641 // If there are any alloca instructions in the block that used to be the entry
642 // block for the callee, move them to the entry block of the caller. First
643 // calculate which instruction they should be inserted before. We insert the
644 // instructions at the end of the current alloca list.
646 BasicBlock::iterator InsertPoint = Caller->begin()->begin();
647 for (BasicBlock::iterator I = FirstNewBlock->begin(),
648 E = FirstNewBlock->end(); I != E; ) {
649 AllocaInst *AI = dyn_cast<AllocaInst>(I++);
650 if (AI == 0) continue;
652 // If the alloca is now dead, remove it. This often occurs due to code
654 if (AI->use_empty()) {
655 AI->eraseFromParent();
659 if (!isa<Constant>(AI->getArraySize()))
662 // Keep track of the static allocas that we inline into the caller.
663 IFI.StaticAllocas.push_back(AI);
665 // Scan for the block of allocas that we can move over, and move them
667 while (isa<AllocaInst>(I) &&
668 isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
669 IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
673 // Transfer all of the allocas over in a block. Using splice means
674 // that the instructions aren't removed from the symbol table, then
676 Caller->getEntryBlock().getInstList().splice(InsertPoint,
677 FirstNewBlock->getInstList(),
682 // Leave lifetime markers for the static alloca's, scoping them to the
683 // function we just inlined.
684 if (InsertLifetime && !IFI.StaticAllocas.empty()) {
685 IRBuilder<> builder(FirstNewBlock->begin());
686 for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
687 AllocaInst *AI = IFI.StaticAllocas[ai];
689 // If the alloca is already scoped to something smaller than the whole
690 // function then there's no need to add redundant, less accurate markers.
691 if (hasLifetimeMarkers(AI))
694 // Try to determine the size of the allocation.
695 ConstantInt *AllocaSize = 0;
696 if (ConstantInt *AIArraySize =
697 dyn_cast<ConstantInt>(AI->getArraySize())) {
699 Type *AllocaType = AI->getAllocatedType();
700 uint64_t AllocaTypeSize = IFI.TD->getTypeAllocSize(AllocaType);
701 uint64_t AllocaArraySize = AIArraySize->getLimitedValue();
702 assert(AllocaArraySize > 0 && "array size of AllocaInst is zero");
703 // Check that array size doesn't saturate uint64_t and doesn't
704 // overflow when it's multiplied by type size.
705 if (AllocaArraySize != ~0ULL &&
706 UINT64_MAX / AllocaArraySize >= AllocaTypeSize) {
707 AllocaSize = ConstantInt::get(Type::getInt64Ty(AI->getContext()),
708 AllocaArraySize * AllocaTypeSize);
713 builder.CreateLifetimeStart(AI, AllocaSize);
714 for (unsigned ri = 0, re = Returns.size(); ri != re; ++ri) {
715 IRBuilder<> builder(Returns[ri]);
716 builder.CreateLifetimeEnd(AI, AllocaSize);
721 // If the inlined code contained dynamic alloca instructions, wrap the inlined
722 // code with llvm.stacksave/llvm.stackrestore intrinsics.
723 if (InlinedFunctionInfo.ContainsDynamicAllocas) {
724 Module *M = Caller->getParent();
725 // Get the two intrinsics we care about.
726 Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
727 Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);
729 // Insert the llvm.stacksave.
730 CallInst *SavedPtr = IRBuilder<>(FirstNewBlock, FirstNewBlock->begin())
731 .CreateCall(StackSave, "savedstack");
733 // Insert a call to llvm.stackrestore before any return instructions in the
735 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
736 IRBuilder<>(Returns[i]).CreateCall(StackRestore, SavedPtr);
740 // If we are inlining tail call instruction through a call site that isn't
741 // marked 'tail', we must remove the tail marker for any calls in the inlined
742 // code. Also, calls inlined through a 'nounwind' call site should be marked
744 if (InlinedFunctionInfo.ContainsCalls &&
745 (MustClearTailCallFlags || MarkNoUnwind)) {
746 for (Function::iterator BB = FirstNewBlock, E = Caller->end();
748 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
749 if (CallInst *CI = dyn_cast<CallInst>(I)) {
750 if (MustClearTailCallFlags)
751 CI->setTailCall(false);
753 CI->setDoesNotThrow();
757 // If we are inlining for an invoke instruction, we must make sure to rewrite
758 // any call instructions into invoke instructions.
759 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
760 HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);
762 // If we cloned in _exactly one_ basic block, and if that block ends in a
763 // return instruction, we splice the body of the inlined callee directly into
764 // the calling basic block.
765 if (Returns.size() == 1 && std::distance(FirstNewBlock, Caller->end()) == 1) {
766 // Move all of the instructions right before the call.
767 OrigBB->getInstList().splice(TheCall, FirstNewBlock->getInstList(),
768 FirstNewBlock->begin(), FirstNewBlock->end());
769 // Remove the cloned basic block.
770 Caller->getBasicBlockList().pop_back();
772 // If the call site was an invoke instruction, add a branch to the normal
774 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
775 BranchInst::Create(II->getNormalDest(), TheCall);
777 // If the return instruction returned a value, replace uses of the call with
778 // uses of the returned value.
779 if (!TheCall->use_empty()) {
780 ReturnInst *R = Returns[0];
781 if (TheCall == R->getReturnValue())
782 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
784 TheCall->replaceAllUsesWith(R->getReturnValue());
786 // Since we are now done with the Call/Invoke, we can delete it.
787 TheCall->eraseFromParent();
789 // Since we are now done with the return instruction, delete it also.
790 Returns[0]->eraseFromParent();
792 // We are now done with the inlining.
796 // Otherwise, we have the normal case, of more than one block to inline or
797 // multiple return sites.
799 // We want to clone the entire callee function into the hole between the
800 // "starter" and "ender" blocks. How we accomplish this depends on whether
801 // this is an invoke instruction or a call instruction.
802 BasicBlock *AfterCallBB;
803 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
805 // Add an unconditional branch to make this look like the CallInst case...
806 BranchInst *NewBr = BranchInst::Create(II->getNormalDest(), TheCall);
808 // Split the basic block. This guarantees that no PHI nodes will have to be
809 // updated due to new incoming edges, and make the invoke case more
810 // symmetric to the call case.
811 AfterCallBB = OrigBB->splitBasicBlock(NewBr,
812 CalledFunc->getName()+".exit");
814 } else { // It's a call
815 // If this is a call instruction, we need to split the basic block that
816 // the call lives in.
818 AfterCallBB = OrigBB->splitBasicBlock(TheCall,
819 CalledFunc->getName()+".exit");
822 // Change the branch that used to go to AfterCallBB to branch to the first
823 // basic block of the inlined function.
825 TerminatorInst *Br = OrigBB->getTerminator();
826 assert(Br && Br->getOpcode() == Instruction::Br &&
827 "splitBasicBlock broken!");
828 Br->setOperand(0, FirstNewBlock);
831 // Now that the function is correct, make it a little bit nicer. In
832 // particular, move the basic blocks inserted from the end of the function
833 // into the space made by splitting the source basic block.
834 Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(),
835 FirstNewBlock, Caller->end());
837 // Handle all of the return instructions that we just cloned in, and eliminate
838 // any users of the original call/invoke instruction.
839 Type *RTy = CalledFunc->getReturnType();
842 if (Returns.size() > 1) {
843 // The PHI node should go at the front of the new basic block to merge all
844 // possible incoming values.
845 if (!TheCall->use_empty()) {
846 PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
847 AfterCallBB->begin());
848 // Anything that used the result of the function call should now use the
849 // PHI node as their operand.
850 TheCall->replaceAllUsesWith(PHI);
853 // Loop over all of the return instructions adding entries to the PHI node
856 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
857 ReturnInst *RI = Returns[i];
858 assert(RI->getReturnValue()->getType() == PHI->getType() &&
859 "Ret value not consistent in function!");
860 PHI->addIncoming(RI->getReturnValue(), RI->getParent());
865 // Add a branch to the merge points and remove return instructions.
866 for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
867 ReturnInst *RI = Returns[i];
868 BranchInst::Create(AfterCallBB, RI);
869 RI->eraseFromParent();
871 } else if (!Returns.empty()) {
872 // Otherwise, if there is exactly one return value, just replace anything
873 // using the return value of the call with the computed value.
874 if (!TheCall->use_empty()) {
875 if (TheCall == Returns[0]->getReturnValue())
876 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
878 TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
881 // Update PHI nodes that use the ReturnBB to use the AfterCallBB.
882 BasicBlock *ReturnBB = Returns[0]->getParent();
883 ReturnBB->replaceAllUsesWith(AfterCallBB);
885 // Splice the code from the return block into the block that it will return
886 // to, which contains the code that was after the call.
887 AfterCallBB->getInstList().splice(AfterCallBB->begin(),
888 ReturnBB->getInstList());
890 // Delete the return instruction now and empty ReturnBB now.
891 Returns[0]->eraseFromParent();
892 ReturnBB->eraseFromParent();
893 } else if (!TheCall->use_empty()) {
894 // No returns, but something is using the return value of the call. Just
896 TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
899 // Since we are now done with the Call/Invoke, we can delete it.
900 TheCall->eraseFromParent();
902 // We should always be able to fold the entry block of the function into the
903 // single predecessor of the block...
904 assert(cast<BranchInst>(Br)->isUnconditional() && "splitBasicBlock broken!");
905 BasicBlock *CalleeEntry = cast<BranchInst>(Br)->getSuccessor(0);
907 // Splice the code entry block into calling block, right before the
908 // unconditional branch.
909 CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
910 OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
912 // Remove the unconditional branch.
913 OrigBB->getInstList().erase(Br);
915 // Now we can remove the CalleeEntry block, which is now empty.
916 Caller->getBasicBlockList().erase(CalleeEntry);
918 // If we inserted a phi node, check to see if it has a single value (e.g. all
919 // the entries are the same or undef). If so, remove the PHI so it doesn't
920 // block other optimizations.
922 if (Value *V = SimplifyInstruction(PHI, IFI.TD)) {
923 PHI->replaceAllUsesWith(V);
924 PHI->eraseFromParent();