1 //===- Inliner.cpp - Code common to all inliners --------------------------===//
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 the mechanics required to implement inlining without
11 // missing any calls and updating the call graph. The decisions of which calls
12 // are profitable to inline are implemented elsewhere.
14 //===----------------------------------------------------------------------===//
16 #define DEBUG_TYPE "inline"
17 #include "llvm/Transforms/IPO/InlinerPass.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/Analysis/CallGraph.h"
21 #include "llvm/Analysis/InlineCost.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/Instructions.h"
24 #include "llvm/IR/IntrinsicInst.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/Support/CallSite.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include "llvm/Target/TargetLibraryInfo.h"
31 #include "llvm/Transforms/Utils/Cloning.h"
32 #include "llvm/Transforms/Utils/Local.h"
35 STATISTIC(NumInlined, "Number of functions inlined");
36 STATISTIC(NumCallsDeleted, "Number of call sites deleted, not inlined");
37 STATISTIC(NumDeleted, "Number of functions deleted because all callers found");
38 STATISTIC(NumMergedAllocas, "Number of allocas merged together");
40 // This weirdly named statistic tracks the number of times that, when attempting
41 // to inline a function A into B, we analyze the callers of B in order to see
42 // if those would be more profitable and blocked inline steps.
43 STATISTIC(NumCallerCallersAnalyzed, "Number of caller-callers analyzed");
46 InlineLimit("inline-threshold", cl::Hidden, cl::init(225), cl::ZeroOrMore,
47 cl::desc("Control the amount of inlining to perform (default = 225)"));
50 HintThreshold("inlinehint-threshold", cl::Hidden, cl::init(325),
51 cl::desc("Threshold for inlining functions with inline hint"));
53 // We instroduce this threshold to help performance of instrumentation based
54 // PGO before we actually hook up inliner with analysis passes such as BPI and
57 ColdThreshold("inlinecold-threshold", cl::Hidden, cl::init(225),
58 cl::desc("Threshold for inlining functions with cold attribute"));
60 // Threshold to use when optsize is specified (and there is no -inline-limit).
61 const int OptSizeThreshold = 75;
63 Inliner::Inliner(char &ID)
64 : CallGraphSCCPass(ID), InlineThreshold(InlineLimit), InsertLifetime(true) {}
66 Inliner::Inliner(char &ID, int Threshold, bool InsertLifetime)
67 : CallGraphSCCPass(ID), InlineThreshold(InlineLimit.getNumOccurrences() > 0 ?
68 InlineLimit : Threshold),
69 InsertLifetime(InsertLifetime) {}
71 /// getAnalysisUsage - For this class, we declare that we require and preserve
72 /// the call graph. If the derived class implements this method, it should
73 /// always explicitly call the implementation here.
74 void Inliner::getAnalysisUsage(AnalysisUsage &AU) const {
75 CallGraphSCCPass::getAnalysisUsage(AU);
79 typedef DenseMap<ArrayType*, std::vector<AllocaInst*> >
80 InlinedArrayAllocasTy;
82 /// \brief If the inlined function had a higher stack protection level than the
83 /// calling function, then bump up the caller's stack protection level.
84 static void AdjustCallerSSPLevel(Function *Caller, Function *Callee) {
85 // If upgrading the SSP attribute, clear out the old SSP Attributes first.
86 // Having multiple SSP attributes doesn't actually hurt, but it adds useless
89 B.addAttribute(Attribute::StackProtect)
90 .addAttribute(Attribute::StackProtectStrong);
91 AttributeSet OldSSPAttr = AttributeSet::get(Caller->getContext(),
92 AttributeSet::FunctionIndex,
94 AttributeSet CallerAttr = Caller->getAttributes(),
95 CalleeAttr = Callee->getAttributes();
97 if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
98 Attribute::StackProtectReq)) {
99 Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
100 Caller->addFnAttr(Attribute::StackProtectReq);
101 } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
102 Attribute::StackProtectStrong) &&
103 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
104 Attribute::StackProtectReq)) {
105 Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
106 Caller->addFnAttr(Attribute::StackProtectStrong);
107 } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
108 Attribute::StackProtect) &&
109 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
110 Attribute::StackProtectReq) &&
111 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
112 Attribute::StackProtectStrong))
113 Caller->addFnAttr(Attribute::StackProtect);
116 /// InlineCallIfPossible - If it is possible to inline the specified call site,
117 /// do so and update the CallGraph for this operation.
119 /// This function also does some basic book-keeping to update the IR. The
120 /// InlinedArrayAllocas map keeps track of any allocas that are already
121 /// available from other functions inlined into the caller. If we are able to
122 /// inline this call site we attempt to reuse already available allocas or add
123 /// any new allocas to the set if not possible.
124 static bool InlineCallIfPossible(CallSite CS, InlineFunctionInfo &IFI,
125 InlinedArrayAllocasTy &InlinedArrayAllocas,
126 int InlineHistory, bool InsertLifetime,
127 const DataLayout *TD) {
128 Function *Callee = CS.getCalledFunction();
129 Function *Caller = CS.getCaller();
131 // Try to inline the function. Get the list of static allocas that were
133 if (!InlineFunction(CS, IFI, InsertLifetime))
136 AdjustCallerSSPLevel(Caller, Callee);
138 // Look at all of the allocas that we inlined through this call site. If we
139 // have already inlined other allocas through other calls into this function,
140 // then we know that they have disjoint lifetimes and that we can merge them.
142 // There are many heuristics possible for merging these allocas, and the
143 // different options have different tradeoffs. One thing that we *really*
144 // don't want to hurt is SRoA: once inlining happens, often allocas are no
145 // longer address taken and so they can be promoted.
147 // Our "solution" for that is to only merge allocas whose outermost type is an
148 // array type. These are usually not promoted because someone is using a
149 // variable index into them. These are also often the most important ones to
152 // A better solution would be to have real memory lifetime markers in the IR
153 // and not have the inliner do any merging of allocas at all. This would
154 // allow the backend to do proper stack slot coloring of all allocas that
155 // *actually make it to the backend*, which is really what we want.
157 // Because we don't have this information, we do this simple and useful hack.
159 SmallPtrSet<AllocaInst*, 16> UsedAllocas;
161 // When processing our SCC, check to see if CS was inlined from some other
162 // call site. For example, if we're processing "A" in this code:
164 // B() { x = alloca ... C() }
165 // C() { y = alloca ... }
166 // Assume that C was not inlined into B initially, and so we're processing A
167 // and decide to inline B into A. Doing this makes an alloca available for
168 // reuse and makes a callsite (C) available for inlining. When we process
169 // the C call site we don't want to do any alloca merging between X and Y
170 // because their scopes are not disjoint. We could make this smarter by
171 // keeping track of the inline history for each alloca in the
172 // InlinedArrayAllocas but this isn't likely to be a significant win.
173 if (InlineHistory != -1) // Only do merging for top-level call sites in SCC.
176 // Loop over all the allocas we have so far and see if they can be merged with
177 // a previously inlined alloca. If not, remember that we had it.
178 for (unsigned AllocaNo = 0, e = IFI.StaticAllocas.size();
179 AllocaNo != e; ++AllocaNo) {
180 AllocaInst *AI = IFI.StaticAllocas[AllocaNo];
182 // Don't bother trying to merge array allocations (they will usually be
183 // canonicalized to be an allocation *of* an array), or allocations whose
184 // type is not itself an array (because we're afraid of pessimizing SRoA).
185 ArrayType *ATy = dyn_cast<ArrayType>(AI->getAllocatedType());
186 if (ATy == 0 || AI->isArrayAllocation())
189 // Get the list of all available allocas for this array type.
190 std::vector<AllocaInst*> &AllocasForType = InlinedArrayAllocas[ATy];
192 // Loop over the allocas in AllocasForType to see if we can reuse one. Note
193 // that we have to be careful not to reuse the same "available" alloca for
194 // multiple different allocas that we just inlined, we use the 'UsedAllocas'
195 // set to keep track of which "available" allocas are being used by this
196 // function. Also, AllocasForType can be empty of course!
197 bool MergedAwayAlloca = false;
198 for (unsigned i = 0, e = AllocasForType.size(); i != e; ++i) {
199 AllocaInst *AvailableAlloca = AllocasForType[i];
201 unsigned Align1 = AI->getAlignment(),
202 Align2 = AvailableAlloca->getAlignment();
203 // If we don't have data layout information, and only one alloca is using
204 // the target default, then we can't safely merge them because we can't
205 // pick the greater alignment.
206 if (!TD && (!Align1 || !Align2) && Align1 != Align2)
209 // The available alloca has to be in the right function, not in some other
210 // function in this SCC.
211 if (AvailableAlloca->getParent() != AI->getParent())
214 // If the inlined function already uses this alloca then we can't reuse
216 if (!UsedAllocas.insert(AvailableAlloca))
219 // Otherwise, we *can* reuse it, RAUW AI into AvailableAlloca and declare
221 DEBUG(dbgs() << " ***MERGED ALLOCA: " << *AI << "\n\t\tINTO: "
222 << *AvailableAlloca << '\n');
224 AI->replaceAllUsesWith(AvailableAlloca);
226 if (Align1 != Align2) {
227 if (!Align1 || !Align2) {
228 assert(TD && "DataLayout required to compare default alignments");
229 unsigned TypeAlign = TD->getABITypeAlignment(AI->getAllocatedType());
231 Align1 = Align1 ? Align1 : TypeAlign;
232 Align2 = Align2 ? Align2 : TypeAlign;
236 AvailableAlloca->setAlignment(AI->getAlignment());
239 AI->eraseFromParent();
240 MergedAwayAlloca = true;
242 IFI.StaticAllocas[AllocaNo] = 0;
246 // If we already nuked the alloca, we're done with it.
247 if (MergedAwayAlloca)
250 // If we were unable to merge away the alloca either because there are no
251 // allocas of the right type available or because we reused them all
252 // already, remember that this alloca came from an inlined function and mark
253 // it used so we don't reuse it for other allocas from this inline
255 AllocasForType.push_back(AI);
256 UsedAllocas.insert(AI);
262 unsigned Inliner::getInlineThreshold(CallSite CS) const {
263 int thres = InlineThreshold; // -inline-threshold or else selected by
266 // If -inline-threshold is not given, listen to the optsize attribute when it
267 // would decrease the threshold.
268 Function *Caller = CS.getCaller();
269 bool OptSize = Caller && !Caller->isDeclaration() &&
270 Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
271 Attribute::OptimizeForSize);
272 if (!(InlineLimit.getNumOccurrences() > 0) && OptSize &&
273 OptSizeThreshold < thres)
274 thres = OptSizeThreshold;
276 // Listen to the inlinehint attribute when it would increase the threshold
277 // and the caller does not need to minimize its size.
278 Function *Callee = CS.getCalledFunction();
279 bool InlineHint = Callee && !Callee->isDeclaration() &&
280 Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
281 Attribute::InlineHint);
282 if (InlineHint && HintThreshold > thres
283 && !Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
285 thres = HintThreshold;
287 // Listen to the cold attribute when it would decrease the threshold.
288 bool ColdCallee = Callee && !Callee->isDeclaration() &&
289 Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
291 if (ColdCallee && ColdThreshold < thres)
292 thres = ColdThreshold;
297 /// shouldInline - Return true if the inliner should attempt to inline
298 /// at the given CallSite.
299 bool Inliner::shouldInline(CallSite CS) {
300 InlineCost IC = getInlineCost(CS);
303 DEBUG(dbgs() << " Inlining: cost=always"
304 << ", Call: " << *CS.getInstruction() << "\n");
309 DEBUG(dbgs() << " NOT Inlining: cost=never"
310 << ", Call: " << *CS.getInstruction() << "\n");
314 Function *Caller = CS.getCaller();
316 DEBUG(dbgs() << " NOT Inlining: cost=" << IC.getCost()
317 << ", thres=" << (IC.getCostDelta() + IC.getCost())
318 << ", Call: " << *CS.getInstruction() << "\n");
322 // Try to detect the case where the current inlining candidate caller (call
323 // it B) is a static or linkonce-ODR function and is an inlining candidate
324 // elsewhere, and the current candidate callee (call it C) is large enough
325 // that inlining it into B would make B too big to inline later. In these
326 // circumstances it may be best not to inline C into B, but to inline B into
329 // This only applies to static and linkonce-ODR functions because those are
330 // expected to be available for inlining in the translation units where they
331 // are used. Thus we will always have the opportunity to make local inlining
332 // decisions. Importantly the linkonce-ODR linkage covers inline functions
333 // and templates in C++.
335 // FIXME: All of this logic should be sunk into getInlineCost. It relies on
336 // the internal implementation of the inline cost metrics rather than
337 // treating them as truly abstract units etc.
338 if (Caller->hasLocalLinkage() ||
339 Caller->getLinkage() == GlobalValue::LinkOnceODRLinkage) {
340 int TotalSecondaryCost = 0;
341 // The candidate cost to be imposed upon the current function.
342 int CandidateCost = IC.getCost() - (InlineConstants::CallPenalty + 1);
343 // This bool tracks what happens if we do NOT inline C into B.
344 bool callerWillBeRemoved = Caller->hasLocalLinkage();
345 // This bool tracks what happens if we DO inline C into B.
346 bool inliningPreventsSomeOuterInline = false;
347 for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
351 // If this isn't a call to Caller (it could be some other sort
352 // of reference) skip it. Such references will prevent the caller
353 // from being removed.
354 if (!CS2 || CS2.getCalledFunction() != Caller) {
355 callerWillBeRemoved = false;
359 InlineCost IC2 = getInlineCost(CS2);
360 ++NumCallerCallersAnalyzed;
362 callerWillBeRemoved = false;
368 // See if inlining or original callsite would erase the cost delta of
369 // this callsite. We subtract off the penalty for the call instruction,
370 // which we would be deleting.
371 if (IC2.getCostDelta() <= CandidateCost) {
372 inliningPreventsSomeOuterInline = true;
373 TotalSecondaryCost += IC2.getCost();
376 // If all outer calls to Caller would get inlined, the cost for the last
377 // one is set very low by getInlineCost, in anticipation that Caller will
378 // be removed entirely. We did not account for this above unless there
379 // is only one caller of Caller.
380 if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
381 TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
383 if (inliningPreventsSomeOuterInline && TotalSecondaryCost < IC.getCost()) {
384 DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
385 " Cost = " << IC.getCost() <<
386 ", outer Cost = " << TotalSecondaryCost << '\n');
391 DEBUG(dbgs() << " Inlining: cost=" << IC.getCost()
392 << ", thres=" << (IC.getCostDelta() + IC.getCost())
393 << ", Call: " << *CS.getInstruction() << '\n');
397 /// InlineHistoryIncludes - Return true if the specified inline history ID
398 /// indicates an inline history that includes the specified function.
399 static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
400 const SmallVectorImpl<std::pair<Function*, int> > &InlineHistory) {
401 while (InlineHistoryID != -1) {
402 assert(unsigned(InlineHistoryID) < InlineHistory.size() &&
403 "Invalid inline history ID");
404 if (InlineHistory[InlineHistoryID].first == F)
406 InlineHistoryID = InlineHistory[InlineHistoryID].second;
411 bool Inliner::runOnSCC(CallGraphSCC &SCC) {
412 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
413 const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
414 const TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
416 SmallPtrSet<Function*, 8> SCCFunctions;
417 DEBUG(dbgs() << "Inliner visiting SCC:");
418 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
419 Function *F = (*I)->getFunction();
420 if (F) SCCFunctions.insert(F);
421 DEBUG(dbgs() << " " << (F ? F->getName() : "INDIRECTNODE"));
424 // Scan through and identify all call sites ahead of time so that we only
425 // inline call sites in the original functions, not call sites that result
426 // from inlining other functions.
427 SmallVector<std::pair<CallSite, int>, 16> CallSites;
429 // When inlining a callee produces new call sites, we want to keep track of
430 // the fact that they were inlined from the callee. This allows us to avoid
431 // infinite inlining in some obscure cases. To represent this, we use an
432 // index into the InlineHistory vector.
433 SmallVector<std::pair<Function*, int>, 8> InlineHistory;
435 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
436 Function *F = (*I)->getFunction();
439 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
440 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
441 CallSite CS(cast<Value>(I));
442 // If this isn't a call, or it is a call to an intrinsic, it can
444 if (!CS || isa<IntrinsicInst>(I))
447 // If this is a direct call to an external function, we can never inline
448 // it. If it is an indirect call, inlining may resolve it to be a
449 // direct call, so we keep it.
450 if (CS.getCalledFunction() && CS.getCalledFunction()->isDeclaration())
453 CallSites.push_back(std::make_pair(CS, -1));
457 DEBUG(dbgs() << ": " << CallSites.size() << " call sites.\n");
459 // If there are no calls in this function, exit early.
460 if (CallSites.empty())
463 // Now that we have all of the call sites, move the ones to functions in the
464 // current SCC to the end of the list.
465 unsigned FirstCallInSCC = CallSites.size();
466 for (unsigned i = 0; i < FirstCallInSCC; ++i)
467 if (Function *F = CallSites[i].first.getCalledFunction())
468 if (SCCFunctions.count(F))
469 std::swap(CallSites[i--], CallSites[--FirstCallInSCC]);
472 InlinedArrayAllocasTy InlinedArrayAllocas;
473 InlineFunctionInfo InlineInfo(&CG, TD);
475 // Now that we have all of the call sites, loop over them and inline them if
476 // it looks profitable to do so.
477 bool Changed = false;
481 // Iterate over the outer loop because inlining functions can cause indirect
482 // calls to become direct calls.
483 for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi) {
484 CallSite CS = CallSites[CSi].first;
486 Function *Caller = CS.getCaller();
487 Function *Callee = CS.getCalledFunction();
489 // If this call site is dead and it is to a readonly function, we should
490 // just delete the call instead of trying to inline it, regardless of
491 // size. This happens because IPSCCP propagates the result out of the
492 // call and then we're left with the dead call.
493 if (isInstructionTriviallyDead(CS.getInstruction(), TLI)) {
494 DEBUG(dbgs() << " -> Deleting dead call: "
495 << *CS.getInstruction() << "\n");
496 // Update the call graph by deleting the edge from Callee to Caller.
497 CG[Caller]->removeCallEdgeFor(CS);
498 CS.getInstruction()->eraseFromParent();
501 // We can only inline direct calls to non-declarations.
502 if (Callee == 0 || Callee->isDeclaration()) continue;
504 // If this call site was obtained by inlining another function, verify
505 // that the include path for the function did not include the callee
506 // itself. If so, we'd be recursively inlining the same function,
507 // which would provide the same callsites, which would cause us to
508 // infinitely inline.
509 int InlineHistoryID = CallSites[CSi].second;
510 if (InlineHistoryID != -1 &&
511 InlineHistoryIncludes(Callee, InlineHistoryID, InlineHistory))
515 // If the policy determines that we should inline this function,
517 if (!shouldInline(CS))
520 // Attempt to inline the function.
521 if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
522 InlineHistoryID, InsertLifetime, TD))
526 // If inlining this function gave us any new call sites, throw them
527 // onto our worklist to process. They are useful inline candidates.
528 if (!InlineInfo.InlinedCalls.empty()) {
529 // Create a new inline history entry for this, so that we remember
530 // that these new callsites came about due to inlining Callee.
531 int NewHistoryID = InlineHistory.size();
532 InlineHistory.push_back(std::make_pair(Callee, InlineHistoryID));
534 for (unsigned i = 0, e = InlineInfo.InlinedCalls.size();
536 Value *Ptr = InlineInfo.InlinedCalls[i];
537 CallSites.push_back(std::make_pair(CallSite(Ptr), NewHistoryID));
542 // If we inlined or deleted the last possible call site to the function,
543 // delete the function body now.
544 if (Callee && Callee->use_empty() && Callee->hasLocalLinkage() &&
545 // TODO: Can remove if in SCC now.
546 !SCCFunctions.count(Callee) &&
548 // The function may be apparently dead, but if there are indirect
549 // callgraph references to the node, we cannot delete it yet, this
550 // could invalidate the CGSCC iterator.
551 CG[Callee]->getNumReferences() == 0) {
552 DEBUG(dbgs() << " -> Deleting dead function: "
553 << Callee->getName() << "\n");
554 CallGraphNode *CalleeNode = CG[Callee];
556 // Remove any call graph edges from the callee to its callees.
557 CalleeNode->removeAllCalledFunctions();
559 // Removing the node for callee from the call graph and delete it.
560 delete CG.removeFunctionFromModule(CalleeNode);
564 // Remove this call site from the list. If possible, use
565 // swap/pop_back for efficiency, but do not use it if doing so would
566 // move a call site to a function in this SCC before the
567 // 'FirstCallInSCC' barrier.
568 if (SCC.isSingular()) {
569 CallSites[CSi] = CallSites.back();
570 CallSites.pop_back();
572 CallSites.erase(CallSites.begin()+CSi);
579 } while (LocalChange);
584 // doFinalization - Remove now-dead linkonce functions at the end of
585 // processing to avoid breaking the SCC traversal.
586 bool Inliner::doFinalization(CallGraph &CG) {
587 return removeDeadFunctions(CG);
590 /// removeDeadFunctions - Remove dead functions that are not included in
591 /// DNR (Do Not Remove) list.
592 bool Inliner::removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly) {
593 SmallVector<CallGraphNode*, 16> FunctionsToRemove;
595 // Scan for all of the functions, looking for ones that should now be removed
596 // from the program. Insert the dead ones in the FunctionsToRemove set.
597 for (CallGraph::iterator I = CG.begin(), E = CG.end(); I != E; ++I) {
598 CallGraphNode *CGN = I->second;
599 Function *F = CGN->getFunction();
600 if (!F || F->isDeclaration())
603 // Handle the case when this function is called and we only want to care
604 // about always-inline functions. This is a bit of a hack to share code
605 // between here and the InlineAlways pass.
606 if (AlwaysInlineOnly &&
607 !F->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
608 Attribute::AlwaysInline))
611 // If the only remaining users of the function are dead constants, remove
613 F->removeDeadConstantUsers();
615 if (!F->isDefTriviallyDead())
618 // Remove any call graph edges from the function to its callees.
619 CGN->removeAllCalledFunctions();
621 // Remove any edges from the external node to the function's call graph
622 // node. These edges might have been made irrelegant due to
623 // optimization of the program.
624 CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
626 // Removing the node for callee from the call graph and delete it.
627 FunctionsToRemove.push_back(CGN);
629 if (FunctionsToRemove.empty())
632 // Now that we know which functions to delete, do so. We didn't want to do
633 // this inline, because that would invalidate our CallGraph::iterator
636 // Note that it doesn't matter that we are iterating over a non-stable order
637 // here to do this, it doesn't matter which order the functions are deleted
639 array_pod_sort(FunctionsToRemove.begin(), FunctionsToRemove.end());
640 FunctionsToRemove.erase(std::unique(FunctionsToRemove.begin(),
641 FunctionsToRemove.end()),
642 FunctionsToRemove.end());
643 for (SmallVectorImpl<CallGraphNode *>::iterator I = FunctionsToRemove.begin(),
644 E = FunctionsToRemove.end();
646 delete CG.removeFunctionFromModule(*I);