1 //==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--//
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 defines the methods for RetainCountChecker, which implements
11 // a reference count checker for Core Foundation and Cocoa on (Mac OS X).
13 //===----------------------------------------------------------------------===//
15 #include "AllocationDiagnostics.h"
16 #include "ClangSACheckers.h"
17 #include "SelectorExtras.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/ParentMap.h"
22 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
23 #include "clang/Basic/LangOptions.h"
24 #include "clang/Basic/SourceManager.h"
25 #include "clang/StaticAnalyzer/Checkers/ObjCRetainCount.h"
26 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
27 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
28 #include "clang/StaticAnalyzer/Core/Checker.h"
29 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
30 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
31 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
32 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
33 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
34 #include "llvm/ADT/DenseMap.h"
35 #include "llvm/ADT/FoldingSet.h"
36 #include "llvm/ADT/ImmutableList.h"
37 #include "llvm/ADT/ImmutableMap.h"
38 #include "llvm/ADT/STLExtras.h"
39 #include "llvm/ADT/SmallString.h"
40 #include "llvm/ADT/StringExtras.h"
44 using namespace clang;
46 using namespace objc_retain;
47 using llvm::StrInStrNoCase;
49 //===----------------------------------------------------------------------===//
50 // Adapters for FoldingSet.
51 //===----------------------------------------------------------------------===//
54 template <> struct FoldingSetTrait<ArgEffect> {
55 static inline void Profile(const ArgEffect X, FoldingSetNodeID &ID) {
56 ID.AddInteger((unsigned) X);
59 template <> struct FoldingSetTrait<RetEffect> {
60 static inline void Profile(const RetEffect &X, FoldingSetNodeID &ID) {
61 ID.AddInteger((unsigned) X.getKind());
62 ID.AddInteger((unsigned) X.getObjKind());
65 } // end llvm namespace
67 //===----------------------------------------------------------------------===//
68 // Reference-counting logic (typestate + counts).
69 //===----------------------------------------------------------------------===//
71 /// ArgEffects summarizes the effects of a function/method call on all of
73 typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects;
79 Owned = 0, // Owning reference.
80 NotOwned, // Reference is not owned by still valid (not freed).
81 Released, // Object has been released.
82 ReturnedOwned, // Returned object passes ownership to caller.
83 ReturnedNotOwned, // Return object does not pass ownership to caller.
85 ErrorDeallocNotOwned, // -dealloc called on non-owned object.
86 ErrorDeallocGC, // Calling -dealloc with GC enabled.
87 ErrorUseAfterRelease, // Object used after released.
88 ErrorReleaseNotOwned, // Release of an object that was not owned.
90 ErrorLeak, // A memory leak due to excessive reference counts.
91 ErrorLeakReturned, // A memory leak due to the returning method not having
92 // the correct naming conventions.
98 /// Tracks how an object referenced by an ivar has been used.
100 /// This accounts for us not knowing if an arbitrary ivar is supposed to be
101 /// stored at +0 or +1.
102 enum class IvarAccessHistory {
105 ReleasedAfterDirectAccess
109 /// The number of outstanding retains.
111 /// The number of outstanding autoreleases.
113 /// The (static) type of the object at the time we started tracking it.
116 /// The current state of the object.
118 /// See the RefVal::Kind enum for possible values.
119 unsigned RawKind : 5;
121 /// The kind of object being tracked (CF or ObjC), if known.
123 /// See the RetEffect::ObjKind enum for possible values.
124 unsigned RawObjectKind : 2;
126 /// True if the current state and/or retain count may turn out to not be the
127 /// best possible approximation of the reference counting state.
129 /// If true, the checker may decide to throw away ("override") this state
130 /// in favor of something else when it sees the object being used in new ways.
132 /// This setting should not be propagated to state derived from this state.
133 /// Once we start deriving new states, it would be inconsistent to override
135 unsigned RawIvarAccessHistory : 2;
137 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t,
138 IvarAccessHistory IvarAccess)
139 : Cnt(cnt), ACnt(acnt), T(t), RawKind(static_cast<unsigned>(k)),
140 RawObjectKind(static_cast<unsigned>(o)),
141 RawIvarAccessHistory(static_cast<unsigned>(IvarAccess)) {
142 assert(getKind() == k && "not enough bits for the kind");
143 assert(getObjKind() == o && "not enough bits for the object kind");
144 assert(getIvarAccessHistory() == IvarAccess && "not enough bits");
148 Kind getKind() const { return static_cast<Kind>(RawKind); }
150 RetEffect::ObjKind getObjKind() const {
151 return static_cast<RetEffect::ObjKind>(RawObjectKind);
154 unsigned getCount() const { return Cnt; }
155 unsigned getAutoreleaseCount() const { return ACnt; }
156 unsigned getCombinedCounts() const { return Cnt + ACnt; }
161 void setCount(unsigned i) {
164 void setAutoreleaseCount(unsigned i) {
168 QualType getType() const { return T; }
170 /// Returns what the analyzer knows about direct accesses to a particular
171 /// instance variable.
173 /// If the object with this refcount wasn't originally from an Objective-C
174 /// ivar region, this should always return IvarAccessHistory::None.
175 IvarAccessHistory getIvarAccessHistory() const {
176 return static_cast<IvarAccessHistory>(RawIvarAccessHistory);
179 bool isOwned() const {
180 return getKind() == Owned;
183 bool isNotOwned() const {
184 return getKind() == NotOwned;
187 bool isReturnedOwned() const {
188 return getKind() == ReturnedOwned;
191 bool isReturnedNotOwned() const {
192 return getKind() == ReturnedNotOwned;
195 /// Create a state for an object whose lifetime is the responsibility of the
196 /// current function, at least partially.
198 /// Most commonly, this is an owned object with a retain count of +1.
199 static RefVal makeOwned(RetEffect::ObjKind o, QualType t,
200 unsigned Count = 1) {
201 return RefVal(Owned, o, Count, 0, t, IvarAccessHistory::None);
204 /// Create a state for an object whose lifetime is not the responsibility of
205 /// the current function.
207 /// Most commonly, this is an unowned object with a retain count of +0.
208 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t,
209 unsigned Count = 0) {
210 return RefVal(NotOwned, o, Count, 0, t, IvarAccessHistory::None);
213 RefVal operator-(size_t i) const {
214 return RefVal(getKind(), getObjKind(), getCount() - i,
215 getAutoreleaseCount(), getType(), getIvarAccessHistory());
218 RefVal operator+(size_t i) const {
219 return RefVal(getKind(), getObjKind(), getCount() + i,
220 getAutoreleaseCount(), getType(), getIvarAccessHistory());
223 RefVal operator^(Kind k) const {
224 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(),
225 getType(), getIvarAccessHistory());
228 RefVal autorelease() const {
229 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1,
230 getType(), getIvarAccessHistory());
233 RefVal withIvarAccess() const {
234 assert(getIvarAccessHistory() == IvarAccessHistory::None);
235 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
236 getType(), IvarAccessHistory::AccessedDirectly);
239 RefVal releaseViaIvar() const {
240 assert(getIvarAccessHistory() == IvarAccessHistory::AccessedDirectly);
241 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
242 getType(), IvarAccessHistory::ReleasedAfterDirectAccess);
245 // Comparison, profiling, and pretty-printing.
247 bool hasSameState(const RefVal &X) const {
248 return getKind() == X.getKind() && Cnt == X.Cnt && ACnt == X.ACnt &&
249 getIvarAccessHistory() == X.getIvarAccessHistory();
252 bool operator==(const RefVal& X) const {
253 return T == X.T && hasSameState(X) && getObjKind() == X.getObjKind();
256 void Profile(llvm::FoldingSetNodeID& ID) const {
258 ID.AddInteger(RawKind);
261 ID.AddInteger(RawObjectKind);
262 ID.AddInteger(RawIvarAccessHistory);
265 void print(raw_ostream &Out) const;
268 void RefVal::print(raw_ostream &Out) const {
270 Out << "Tracked " << T.getAsString() << '/';
273 default: llvm_unreachable("Invalid RefVal kind");
276 unsigned cnt = getCount();
277 if (cnt) Out << " (+ " << cnt << ")";
283 unsigned cnt = getCount();
284 if (cnt) Out << " (+ " << cnt << ")";
288 case ReturnedOwned: {
289 Out << "ReturnedOwned";
290 unsigned cnt = getCount();
291 if (cnt) Out << " (+ " << cnt << ")";
295 case ReturnedNotOwned: {
296 Out << "ReturnedNotOwned";
297 unsigned cnt = getCount();
298 if (cnt) Out << " (+ " << cnt << ")";
307 Out << "-dealloc (GC)";
310 case ErrorDeallocNotOwned:
311 Out << "-dealloc (not-owned)";
318 case ErrorLeakReturned:
319 Out << "Leaked (Bad naming)";
322 case ErrorGCLeakReturned:
323 Out << "Leaked (GC-ed at return)";
326 case ErrorUseAfterRelease:
327 Out << "Use-After-Release [ERROR]";
330 case ErrorReleaseNotOwned:
331 Out << "Release of Not-Owned [ERROR]";
334 case RefVal::ErrorOverAutorelease:
335 Out << "Over-autoreleased";
338 case RefVal::ErrorReturnedNotOwned:
339 Out << "Non-owned object returned instead of owned";
343 switch (getIvarAccessHistory()) {
344 case IvarAccessHistory::None:
346 case IvarAccessHistory::AccessedDirectly:
347 Out << " [direct ivar access]";
349 case IvarAccessHistory::ReleasedAfterDirectAccess:
350 Out << " [released after direct ivar access]";
354 Out << " [autorelease -" << ACnt << ']';
357 } //end anonymous namespace
359 //===----------------------------------------------------------------------===//
360 // RefBindings - State used to track object reference counts.
361 //===----------------------------------------------------------------------===//
363 REGISTER_MAP_WITH_PROGRAMSTATE(RefBindings, SymbolRef, RefVal)
365 static inline const RefVal *getRefBinding(ProgramStateRef State,
367 return State->get<RefBindings>(Sym);
370 static inline ProgramStateRef setRefBinding(ProgramStateRef State,
371 SymbolRef Sym, RefVal Val) {
372 return State->set<RefBindings>(Sym, Val);
375 static ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) {
376 return State->remove<RefBindings>(Sym);
379 //===----------------------------------------------------------------------===//
380 // Function/Method behavior summaries.
381 //===----------------------------------------------------------------------===//
384 class RetainSummary {
385 /// Args - a map of (index, ArgEffect) pairs, where index
386 /// specifies the argument (starting from 0). This can be sparsely
387 /// populated; arguments with no entry in Args use 'DefaultArgEffect'.
390 /// DefaultArgEffect - The default ArgEffect to apply to arguments that
391 /// do not have an entry in Args.
392 ArgEffect DefaultArgEffect;
394 /// Receiver - If this summary applies to an Objective-C message expression,
395 /// this is the effect applied to the state of the receiver.
398 /// Ret - The effect on the return value. Used to indicate if the
399 /// function/method call returns a new tracked symbol.
403 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff,
404 ArgEffect ReceiverEff)
405 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {}
407 /// getArg - Return the argument effect on the argument specified by
408 /// idx (starting from 0).
409 ArgEffect getArg(unsigned idx) const {
410 if (const ArgEffect *AE = Args.lookup(idx))
413 return DefaultArgEffect;
416 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) {
417 Args = af.add(Args, idx, e);
420 /// setDefaultArgEffect - Set the default argument effect.
421 void setDefaultArgEffect(ArgEffect E) {
422 DefaultArgEffect = E;
425 /// getRetEffect - Returns the effect on the return value of the call.
426 RetEffect getRetEffect() const { return Ret; }
428 /// setRetEffect - Set the effect of the return value of the call.
429 void setRetEffect(RetEffect E) { Ret = E; }
432 /// Sets the effect on the receiver of the message.
433 void setReceiverEffect(ArgEffect e) { Receiver = e; }
435 /// getReceiverEffect - Returns the effect on the receiver of the call.
436 /// This is only meaningful if the summary applies to an ObjCMessageExpr*.
437 ArgEffect getReceiverEffect() const { return Receiver; }
439 /// Test if two retain summaries are identical. Note that merely equivalent
440 /// summaries are not necessarily identical (for example, if an explicit
441 /// argument effect matches the default effect).
442 bool operator==(const RetainSummary &Other) const {
443 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect &&
444 Receiver == Other.Receiver && Ret == Other.Ret;
447 /// Profile this summary for inclusion in a FoldingSet.
448 void Profile(llvm::FoldingSetNodeID& ID) const {
450 ID.Add(DefaultArgEffect);
455 /// A retain summary is simple if it has no ArgEffects other than the default.
456 bool isSimple() const {
457 return Args.isEmpty();
461 ArgEffects getArgEffects() const { return Args; }
462 ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; }
464 friend class RetainSummaryManager;
466 } // end anonymous namespace
468 //===----------------------------------------------------------------------===//
469 // Data structures for constructing summaries.
470 //===----------------------------------------------------------------------===//
473 class ObjCSummaryKey {
477 ObjCSummaryKey(IdentifierInfo* ii, Selector s)
480 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s)
481 : II(d ? d->getIdentifier() : nullptr), S(s) {}
483 ObjCSummaryKey(Selector s)
484 : II(nullptr), S(s) {}
486 IdentifierInfo *getIdentifier() const { return II; }
487 Selector getSelector() const { return S; }
489 } // end anonymous namespace
492 template <> struct DenseMapInfo<ObjCSummaryKey> {
493 static inline ObjCSummaryKey getEmptyKey() {
494 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(),
495 DenseMapInfo<Selector>::getEmptyKey());
498 static inline ObjCSummaryKey getTombstoneKey() {
499 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(),
500 DenseMapInfo<Selector>::getTombstoneKey());
503 static unsigned getHashValue(const ObjCSummaryKey &V) {
504 typedef std::pair<IdentifierInfo*, Selector> PairTy;
505 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(),
509 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) {
510 return LHS.getIdentifier() == RHS.getIdentifier() &&
511 LHS.getSelector() == RHS.getSelector();
515 } // end llvm namespace
518 class ObjCSummaryCache {
519 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy;
522 ObjCSummaryCache() {}
524 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) {
525 // Do a lookup with the (D,S) pair. If we find a match return
527 ObjCSummaryKey K(D, S);
528 MapTy::iterator I = M.find(K);
535 // Walk the super chain. If we find a hit with a parent, we'll end
536 // up returning that summary. We actually allow that key (null,S), as
537 // we cache summaries for the null ObjCInterfaceDecl* to allow us to
538 // generate initial summaries without having to worry about NSObject
540 // FIXME: We may change this at some point.
541 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) {
542 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end())
549 // Cache the summary with original key to make the next lookup faster
550 // and return the iterator.
551 const RetainSummary *Summ = I->second;
556 const RetainSummary *find(IdentifierInfo* II, Selector S) {
557 // FIXME: Class method lookup. Right now we dont' have a good way
558 // of going between IdentifierInfo* and the class hierarchy.
559 MapTy::iterator I = M.find(ObjCSummaryKey(II, S));
562 I = M.find(ObjCSummaryKey(S));
564 return I == M.end() ? nullptr : I->second;
567 const RetainSummary *& operator[](ObjCSummaryKey K) {
571 const RetainSummary *& operator[](Selector S) {
572 return M[ ObjCSummaryKey(S) ];
575 } // end anonymous namespace
577 //===----------------------------------------------------------------------===//
578 // Data structures for managing collections of summaries.
579 //===----------------------------------------------------------------------===//
582 class RetainSummaryManager {
584 //==-----------------------------------------------------------------==//
586 //==-----------------------------------------------------------------==//
588 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *>
591 typedef ObjCSummaryCache ObjCMethodSummariesTy;
593 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode;
595 //==-----------------------------------------------------------------==//
597 //==-----------------------------------------------------------------==//
599 /// Ctx - The ASTContext object for the analyzed ASTs.
602 /// GCEnabled - Records whether or not the analyzed code runs in GC mode.
603 const bool GCEnabled;
605 /// Records whether or not the analyzed code runs in ARC mode.
606 const bool ARCEnabled;
608 /// FuncSummaries - A map from FunctionDecls to summaries.
609 FuncSummariesTy FuncSummaries;
611 /// ObjCClassMethodSummaries - A map from selectors (for instance methods)
613 ObjCMethodSummariesTy ObjCClassMethodSummaries;
615 /// ObjCMethodSummaries - A map from selectors to summaries.
616 ObjCMethodSummariesTy ObjCMethodSummaries;
618 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects,
619 /// and all other data used by the checker.
620 llvm::BumpPtrAllocator BPAlloc;
622 /// AF - A factory for ArgEffects objects.
623 ArgEffects::Factory AF;
625 /// ScratchArgs - A holding buffer for construct ArgEffects.
626 ArgEffects ScratchArgs;
628 /// ObjCAllocRetE - Default return effect for methods returning Objective-C
630 RetEffect ObjCAllocRetE;
632 /// ObjCInitRetE - Default return effect for init methods returning
633 /// Objective-C objects.
634 RetEffect ObjCInitRetE;
636 /// SimpleSummaries - Used for uniquing summaries that don't have special
638 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries;
640 //==-----------------------------------------------------------------==//
642 //==-----------------------------------------------------------------==//
644 /// getArgEffects - Returns a persistent ArgEffects object based on the
645 /// data in ScratchArgs.
646 ArgEffects getArgEffects();
648 enum UnaryFuncKind { cfretain, cfrelease, cfautorelease, cfmakecollectable };
650 const RetainSummary *getUnarySummary(const FunctionType* FT,
653 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD);
654 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD);
655 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD);
657 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm);
659 const RetainSummary *getPersistentSummary(RetEffect RetEff,
660 ArgEffect ReceiverEff = DoNothing,
661 ArgEffect DefaultEff = MayEscape) {
662 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff);
663 return getPersistentSummary(Summ);
666 const RetainSummary *getDoNothingSummary() {
667 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
670 const RetainSummary *getDefaultSummary() {
671 return getPersistentSummary(RetEffect::MakeNoRet(),
672 DoNothing, MayEscape);
675 const RetainSummary *getPersistentStopSummary() {
676 return getPersistentSummary(RetEffect::MakeNoRet(),
677 StopTracking, StopTracking);
680 void InitializeClassMethodSummaries();
681 void InitializeMethodSummaries();
683 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) {
684 ObjCClassMethodSummaries[S] = Summ;
687 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) {
688 ObjCMethodSummaries[S] = Summ;
691 void addClassMethSummary(const char* Cls, const char* name,
692 const RetainSummary *Summ, bool isNullary = true) {
693 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
694 Selector S = isNullary ? GetNullarySelector(name, Ctx)
695 : GetUnarySelector(name, Ctx);
696 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
699 void addInstMethSummary(const char* Cls, const char* nullaryName,
700 const RetainSummary *Summ) {
701 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls);
702 Selector S = GetNullarySelector(nullaryName, Ctx);
703 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ;
706 template <typename... Keywords>
707 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy &Summaries,
708 const RetainSummary *Summ, Keywords *... Kws) {
709 Selector S = getKeywordSelector(Ctx, Kws...);
710 Summaries[ObjCSummaryKey(ClsII, S)] = Summ;
713 template <typename... Keywords>
714 void addInstMethSummary(const char *Cls, const RetainSummary *Summ,
716 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, Kws...);
719 template <typename... Keywords>
720 void addClsMethSummary(const char *Cls, const RetainSummary *Summ,
722 addMethodSummary(&Ctx.Idents.get(Cls), ObjCClassMethodSummaries, Summ,
726 template <typename... Keywords>
727 void addClsMethSummary(IdentifierInfo *II, const RetainSummary *Summ,
729 addMethodSummary(II, ObjCClassMethodSummaries, Summ, Kws...);
734 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC)
736 GCEnabled(gcenabled),
738 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()),
739 ObjCAllocRetE(gcenabled
740 ? RetEffect::MakeGCNotOwned()
741 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
742 : RetEffect::MakeOwned(RetEffect::ObjC))),
743 ObjCInitRetE(gcenabled
744 ? RetEffect::MakeGCNotOwned()
745 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
746 : RetEffect::MakeOwnedWhenTrackedReceiver())) {
747 InitializeClassMethodSummaries();
748 InitializeMethodSummaries();
751 const RetainSummary *getSummary(const CallEvent &Call,
752 ProgramStateRef State = nullptr);
754 const RetainSummary *getFunctionSummary(const FunctionDecl *FD);
756 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
757 const ObjCMethodDecl *MD,
759 ObjCMethodSummariesTy &CachedSummaries);
761 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M,
762 ProgramStateRef State);
764 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) {
765 assert(!M.isInstanceMessage());
766 const ObjCInterfaceDecl *Class = M.getReceiverInterface();
768 return getMethodSummary(M.getSelector(), Class, M.getDecl(),
769 M.getResultType(), ObjCClassMethodSummaries);
772 /// getMethodSummary - This version of getMethodSummary is used to query
773 /// the summary for the current method being analyzed.
774 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) {
775 const ObjCInterfaceDecl *ID = MD->getClassInterface();
776 Selector S = MD->getSelector();
777 QualType ResultTy = MD->getReturnType();
779 ObjCMethodSummariesTy *CachedSummaries;
780 if (MD->isInstanceMethod())
781 CachedSummaries = &ObjCMethodSummaries;
783 CachedSummaries = &ObjCClassMethodSummaries;
785 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries);
788 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD,
789 Selector S, QualType RetTy);
791 /// Determine if there is a special return effect for this function or method.
792 Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy,
795 void updateSummaryFromAnnotations(const RetainSummary *&Summ,
796 const ObjCMethodDecl *MD);
798 void updateSummaryFromAnnotations(const RetainSummary *&Summ,
799 const FunctionDecl *FD);
801 void updateSummaryForCall(const RetainSummary *&Summ,
802 const CallEvent &Call);
804 bool isGCEnabled() const { return GCEnabled; }
806 bool isARCEnabled() const { return ARCEnabled; }
808 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; }
810 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; }
812 friend class RetainSummaryTemplate;
815 // Used to avoid allocating long-term (BPAlloc'd) memory for default retain
816 // summaries. If a function or method looks like it has a default summary, but
817 // it has annotations, the annotations are added to the stack-based template
818 // and then copied into managed memory.
819 class RetainSummaryTemplate {
820 RetainSummaryManager &Manager;
821 const RetainSummary *&RealSummary;
822 RetainSummary ScratchSummary;
825 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr)
826 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {}
828 ~RetainSummaryTemplate() {
830 RealSummary = Manager.getPersistentSummary(ScratchSummary);
833 RetainSummary &operator*() {
835 return ScratchSummary;
838 RetainSummary *operator->() {
840 return &ScratchSummary;
844 } // end anonymous namespace
846 //===----------------------------------------------------------------------===//
847 // Implementation of checker data structures.
848 //===----------------------------------------------------------------------===//
850 ArgEffects RetainSummaryManager::getArgEffects() {
851 ArgEffects AE = ScratchArgs;
852 ScratchArgs = AF.getEmptyMap();
856 const RetainSummary *
857 RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) {
858 // Unique "simple" summaries -- those without ArgEffects.
859 if (OldSumm.isSimple()) {
860 llvm::FoldingSetNodeID ID;
864 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos);
867 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>();
868 new (N) CachedSummaryNode(OldSumm);
869 SimpleSummaries.InsertNode(N, Pos);
872 return &N->getValue();
875 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>();
876 new (Summ) RetainSummary(OldSumm);
880 //===----------------------------------------------------------------------===//
881 // Summary creation for functions (largely uses of Core Foundation).
882 //===----------------------------------------------------------------------===//
884 static bool isRetain(const FunctionDecl *FD, StringRef FName) {
885 return FName.endswith("Retain");
888 static bool isRelease(const FunctionDecl *FD, StringRef FName) {
889 return FName.endswith("Release");
892 static bool isAutorelease(const FunctionDecl *FD, StringRef FName) {
893 return FName.endswith("Autorelease");
896 static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) {
897 // FIXME: Remove FunctionDecl parameter.
898 // FIXME: Is it really okay if MakeCollectable isn't a suffix?
899 return FName.find("MakeCollectable") != StringRef::npos;
902 static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) {
906 case DecRefBridgedTransferred:
909 case MakeCollectable:
910 case UnretainedOutParameter:
911 case RetainedOutParameter:
914 case StopTrackingHard:
915 return StopTrackingHard;
917 case DecRefAndStopTrackingHard:
918 return DecRefAndStopTrackingHard;
920 case DecRefMsgAndStopTrackingHard:
921 return DecRefMsgAndStopTrackingHard;
926 llvm_unreachable("Unknown ArgEffect kind");
929 void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S,
930 const CallEvent &Call) {
931 if (Call.hasNonZeroCallbackArg()) {
932 ArgEffect RecEffect =
933 getStopTrackingHardEquivalent(S->getReceiverEffect());
934 ArgEffect DefEffect =
935 getStopTrackingHardEquivalent(S->getDefaultArgEffect());
937 ArgEffects CustomArgEffects = S->getArgEffects();
938 for (ArgEffects::iterator I = CustomArgEffects.begin(),
939 E = CustomArgEffects.end();
941 ArgEffect Translated = getStopTrackingHardEquivalent(I->second);
942 if (Translated != DefEffect)
943 ScratchArgs = AF.add(ScratchArgs, I->first, Translated);
946 RetEffect RE = RetEffect::MakeNoRetHard();
948 // Special cases where the callback argument CANNOT free the return value.
949 // This can generally only happen if we know that the callback will only be
950 // called when the return value is already being deallocated.
951 if (const SimpleFunctionCall *FC = dyn_cast<SimpleFunctionCall>(&Call)) {
952 if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) {
953 // When the CGBitmapContext is deallocated, the callback here will free
954 // the associated data buffer.
955 // The callback in dispatch_data_create frees the buffer, but not
957 if (Name->isStr("CGBitmapContextCreateWithData") ||
958 Name->isStr("dispatch_data_create"))
959 RE = S->getRetEffect();
963 S = getPersistentSummary(RE, RecEffect, DefEffect);
966 // Special case '[super init];' and '[self init];'
968 // Even though calling '[super init]' without assigning the result to self
969 // and checking if the parent returns 'nil' is a bad pattern, it is common.
970 // Additionally, our Self Init checker already warns about it. To avoid
971 // overwhelming the user with messages from both checkers, we model the case
972 // of '[super init]' in cases when it is not consumed by another expression
973 // as if the call preserves the value of 'self'; essentially, assuming it can
974 // never fail and return 'nil'.
975 // Note, we don't want to just stop tracking the value since we want the
976 // RetainCount checker to report leaks and use-after-free if SelfInit checker
978 if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) {
979 if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) {
981 // Check if the message is not consumed, we know it will not be used in
982 // an assignment, ex: "self = [super init]".
983 const Expr *ME = MC->getOriginExpr();
984 const LocationContext *LCtx = MC->getLocationContext();
985 ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap();
986 if (!PM.isConsumedExpr(ME)) {
987 RetainSummaryTemplate ModifiableSummaryTemplate(S, *this);
988 ModifiableSummaryTemplate->setReceiverEffect(DoNothing);
989 ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet());
995 const RetainSummary *
996 RetainSummaryManager::getSummary(const CallEvent &Call,
997 ProgramStateRef State) {
998 const RetainSummary *Summ;
999 switch (Call.getKind()) {
1001 Summ = getFunctionSummary(cast<SimpleFunctionCall>(Call).getDecl());
1004 case CE_CXXMemberOperator:
1006 case CE_CXXConstructor:
1007 case CE_CXXDestructor:
1008 case CE_CXXAllocator:
1009 // FIXME: These calls are currently unsupported.
1010 return getPersistentStopSummary();
1011 case CE_ObjCMessage: {
1012 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call);
1013 if (Msg.isInstanceMessage())
1014 Summ = getInstanceMethodSummary(Msg, State);
1016 Summ = getClassMethodSummary(Msg);
1021 updateSummaryForCall(Summ, Call);
1023 assert(Summ && "Unknown call type?");
1027 const RetainSummary *
1028 RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
1029 // If we don't know what function we're calling, use our default summary.
1031 return getDefaultSummary();
1033 // Look up a summary in our cache of FunctionDecls -> Summaries.
1034 FuncSummariesTy::iterator I = FuncSummaries.find(FD);
1035 if (I != FuncSummaries.end())
1038 // No summary? Generate one.
1039 const RetainSummary *S = nullptr;
1040 bool AllowAnnotations = true;
1043 // We generate "stop" summaries for implicitly defined functions.
1044 if (FD->isImplicit()) {
1045 S = getPersistentStopSummary();
1049 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the
1051 const FunctionType* FT = FD->getType()->getAs<FunctionType>();
1052 const IdentifierInfo *II = FD->getIdentifier();
1056 StringRef FName = II->getName();
1058 // Strip away preceding '_'. Doing this here will effect all the checks
1060 FName = FName.substr(FName.find_first_not_of('_'));
1062 // Inspect the result type.
1063 QualType RetTy = FT->getReturnType();
1065 // FIXME: This should all be refactored into a chain of "summary lookup"
1067 assert(ScratchArgs.isEmpty());
1069 if (FName == "pthread_create" || FName == "pthread_setspecific") {
1070 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>.
1071 // This will be addressed better with IPA.
1072 S = getPersistentStopSummary();
1073 } else if (FName == "NSMakeCollectable") {
1074 // Handle: id NSMakeCollectable(CFTypeRef)
1075 S = (RetTy->isObjCIdType())
1076 ? getUnarySummary(FT, cfmakecollectable)
1077 : getPersistentStopSummary();
1078 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained,
1079 // but we can fully model NSMakeCollectable ourselves.
1080 AllowAnnotations = false;
1081 } else if (FName == "CFPlugInInstanceCreate") {
1082 S = getPersistentSummary(RetEffect::MakeNoRet());
1083 } else if (FName == "IOBSDNameMatching" ||
1084 FName == "IOServiceMatching" ||
1085 FName == "IOServiceNameMatching" ||
1086 FName == "IORegistryEntrySearchCFProperty" ||
1087 FName == "IORegistryEntryIDMatching" ||
1088 FName == "IOOpenFirmwarePathMatching") {
1089 // Part of <rdar://problem/6961230>. (IOKit)
1090 // This should be addressed using a API table.
1091 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
1092 DoNothing, DoNothing);
1093 } else if (FName == "IOServiceGetMatchingService" ||
1094 FName == "IOServiceGetMatchingServices") {
1095 // FIXES: <rdar://problem/6326900>
1096 // This should be addressed using a API table. This strcmp is also
1097 // a little gross, but there is no need to super optimize here.
1098 ScratchArgs = AF.add(ScratchArgs, 1, DecRef);
1099 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1100 } else if (FName == "IOServiceAddNotification" ||
1101 FName == "IOServiceAddMatchingNotification") {
1102 // Part of <rdar://problem/6961230>. (IOKit)
1103 // This should be addressed using a API table.
1104 ScratchArgs = AF.add(ScratchArgs, 2, DecRef);
1105 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1106 } else if (FName == "CVPixelBufferCreateWithBytes") {
1107 // FIXES: <rdar://problem/7283567>
1108 // Eventually this can be improved by recognizing that the pixel
1109 // buffer passed to CVPixelBufferCreateWithBytes is released via
1110 // a callback and doing full IPA to make sure this is done correctly.
1111 // FIXME: This function has an out parameter that returns an
1112 // allocated object.
1113 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking);
1114 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1115 } else if (FName == "CGBitmapContextCreateWithData") {
1116 // FIXES: <rdar://problem/7358899>
1117 // Eventually this can be improved by recognizing that 'releaseInfo'
1118 // passed to CGBitmapContextCreateWithData is released via
1119 // a callback and doing full IPA to make sure this is done correctly.
1120 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking);
1121 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
1122 DoNothing, DoNothing);
1123 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") {
1124 // FIXES: <rdar://problem/7283567>
1125 // Eventually this can be improved by recognizing that the pixel
1126 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released
1127 // via a callback and doing full IPA to make sure this is done
1129 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking);
1130 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1131 } else if (FName == "VTCompressionSessionEncodeFrame") {
1132 // The context argument passed to VTCompressionSessionEncodeFrame()
1133 // is passed to the callback specified when creating the session
1134 // (e.g. with VTCompressionSessionCreate()) which can release it.
1135 // To account for this possibility, conservatively stop tracking
1137 ScratchArgs = AF.add(ScratchArgs, 5, StopTracking);
1138 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1139 } else if (FName == "dispatch_set_context" ||
1140 FName == "xpc_connection_set_context") {
1141 // <rdar://problem/11059275> - The analyzer currently doesn't have
1142 // a good way to reason about the finalizer function for libdispatch.
1143 // If we pass a context object that is memory managed, stop tracking it.
1144 // <rdar://problem/13783514> - Same problem, but for XPC.
1145 // FIXME: this hack should possibly go away once we can handle
1146 // libdispatch and XPC finalizers.
1147 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
1148 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1149 } else if (FName.startswith("NSLog")) {
1150 S = getDoNothingSummary();
1151 } else if (FName.startswith("NS") &&
1152 (FName.find("Insert") != StringRef::npos)) {
1153 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
1154 // be deallocated by NSMapRemove. (radar://11152419)
1155 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
1156 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking);
1157 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1160 // Did we get a summary?
1164 if (RetTy->isPointerType()) {
1165 // For CoreFoundation ('CF') types.
1166 if (cocoa::isRefType(RetTy, "CF", FName)) {
1167 if (isRetain(FD, FName)) {
1168 S = getUnarySummary(FT, cfretain);
1169 } else if (isAutorelease(FD, FName)) {
1170 S = getUnarySummary(FT, cfautorelease);
1171 // The headers use cf_consumed, but we can fully model CFAutorelease
1173 AllowAnnotations = false;
1174 } else if (isMakeCollectable(FD, FName)) {
1175 S = getUnarySummary(FT, cfmakecollectable);
1176 AllowAnnotations = false;
1178 S = getCFCreateGetRuleSummary(FD);
1184 // For CoreGraphics ('CG') and CoreVideo ('CV') types.
1185 if (cocoa::isRefType(RetTy, "CG", FName) ||
1186 cocoa::isRefType(RetTy, "CV", FName)) {
1187 if (isRetain(FD, FName))
1188 S = getUnarySummary(FT, cfretain);
1190 S = getCFCreateGetRuleSummary(FD);
1195 // For the Disk Arbitration API (DiskArbitration/DADisk.h)
1196 if (cocoa::isRefType(RetTy, "DADisk") ||
1197 cocoa::isRefType(RetTy, "DADissenter") ||
1198 cocoa::isRefType(RetTy, "DASessionRef")) {
1199 S = getCFCreateGetRuleSummary(FD);
1203 if (FD->hasAttr<CFAuditedTransferAttr>()) {
1204 S = getCFCreateGetRuleSummary(FD);
1211 // Check for release functions, the only kind of functions that we care
1212 // about that don't return a pointer type.
1213 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) {
1215 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2);
1217 if (isRelease(FD, FName))
1218 S = getUnarySummary(FT, cfrelease);
1220 assert (ScratchArgs.isEmpty());
1221 // Remaining CoreFoundation and CoreGraphics functions.
1222 // We use to assume that they all strictly followed the ownership idiom
1223 // and that ownership cannot be transferred. While this is technically
1224 // correct, many methods allow a tracked object to escape. For example:
1226 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...);
1227 // CFDictionaryAddValue(y, key, x);
1229 // ... it is okay to use 'x' since 'y' has a reference to it
1231 // We handle this and similar cases with the follow heuristic. If the
1232 // function name contains "InsertValue", "SetValue", "AddValue",
1233 // "AppendValue", or "SetAttribute", then we assume that arguments may
1234 // "escape." This means that something else holds on to the object,
1235 // allowing it be used even after its local retain count drops to 0.
1236 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos||
1237 StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
1238 StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
1239 StrInStrNoCase(FName, "AppendValue") != StringRef::npos||
1240 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos)
1241 ? MayEscape : DoNothing;
1243 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E);
1249 // If we got all the way here without any luck, use a default summary.
1251 S = getDefaultSummary();
1253 // Annotations override defaults.
1254 if (AllowAnnotations)
1255 updateSummaryFromAnnotations(S, FD);
1257 FuncSummaries[FD] = S;
1261 const RetainSummary *
1262 RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) {
1263 if (coreFoundation::followsCreateRule(FD))
1264 return getCFSummaryCreateRule(FD);
1266 return getCFSummaryGetRule(FD);
1269 const RetainSummary *
1270 RetainSummaryManager::getUnarySummary(const FunctionType* FT,
1271 UnaryFuncKind func) {
1273 // Sanity check that this is *really* a unary function. This can
1274 // happen if people do weird things.
1275 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT);
1276 if (!FTP || FTP->getNumParams() != 1)
1277 return getPersistentStopSummary();
1279 assert (ScratchArgs.isEmpty());
1283 case cfretain: Effect = IncRef; break;
1284 case cfrelease: Effect = DecRef; break;
1285 case cfautorelease: Effect = Autorelease; break;
1286 case cfmakecollectable: Effect = MakeCollectable; break;
1289 ScratchArgs = AF.add(ScratchArgs, 0, Effect);
1290 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1293 const RetainSummary *
1294 RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) {
1295 assert (ScratchArgs.isEmpty());
1297 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF));
1300 const RetainSummary *
1301 RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) {
1302 assert (ScratchArgs.isEmpty());
1303 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF),
1304 DoNothing, DoNothing);
1307 /// Returns true if the declaration 'D' is annotated with 'rcAnnotation'.
1308 static bool hasRCAnnotation(const Decl *D, StringRef rcAnnotation) {
1309 for (const auto *Ann : D->specific_attrs<AnnotateAttr>()) {
1310 if (Ann->getAnnotation() == rcAnnotation)
1316 /// Returns true if the function declaration 'FD' contains
1317 /// 'rc_ownership_trusted_implementation' annotate attribute.
1318 static bool isTrustedReferenceCountImplementation(const FunctionDecl *FD) {
1319 return hasRCAnnotation(FD, "rc_ownership_trusted_implementation");
1322 //===----------------------------------------------------------------------===//
1323 // Summary creation for Selectors.
1324 //===----------------------------------------------------------------------===//
1327 RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy,
1329 if (cocoa::isCocoaObjectRef(RetTy)) {
1330 if (D->hasAttr<NSReturnsRetainedAttr>())
1331 return ObjCAllocRetE;
1333 if (D->hasAttr<NSReturnsNotRetainedAttr>() ||
1334 D->hasAttr<NSReturnsAutoreleasedAttr>())
1335 return RetEffect::MakeNotOwned(RetEffect::ObjC);
1337 } else if (!RetTy->isPointerType()) {
1341 if (D->hasAttr<CFReturnsRetainedAttr>())
1342 return RetEffect::MakeOwned(RetEffect::CF);
1344 if (D->hasAttr<CFReturnsNotRetainedAttr>())
1345 return RetEffect::MakeNotOwned(RetEffect::CF);
1351 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
1352 const FunctionDecl *FD) {
1356 assert(Summ && "Must have a summary to add annotations to.");
1357 RetainSummaryTemplate Template(Summ, *this);
1359 // Effects on the parameters.
1360 unsigned parm_idx = 0;
1361 for (FunctionDecl::param_const_iterator pi = FD->param_begin(),
1362 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) {
1363 const ParmVarDecl *pd = *pi;
1364 if (pd->hasAttr<NSConsumedAttr>())
1365 Template->addArg(AF, parm_idx, DecRefMsg);
1366 else if (pd->hasAttr<CFConsumedAttr>())
1367 Template->addArg(AF, parm_idx, DecRef);
1368 else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
1369 QualType PointeeTy = pd->getType()->getPointeeType();
1370 if (!PointeeTy.isNull())
1371 if (coreFoundation::isCFObjectRef(PointeeTy))
1372 Template->addArg(AF, parm_idx, RetainedOutParameter);
1373 } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
1374 QualType PointeeTy = pd->getType()->getPointeeType();
1375 if (!PointeeTy.isNull())
1376 if (coreFoundation::isCFObjectRef(PointeeTy))
1377 Template->addArg(AF, parm_idx, UnretainedOutParameter);
1381 QualType RetTy = FD->getReturnType();
1382 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD))
1383 Template->setRetEffect(*RetE);
1387 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
1388 const ObjCMethodDecl *MD) {
1392 assert(Summ && "Must have a valid summary to add annotations to");
1393 RetainSummaryTemplate Template(Summ, *this);
1395 // Effects on the receiver.
1396 if (MD->hasAttr<NSConsumesSelfAttr>())
1397 Template->setReceiverEffect(DecRefMsg);
1399 // Effects on the parameters.
1400 unsigned parm_idx = 0;
1401 for (ObjCMethodDecl::param_const_iterator
1402 pi=MD->param_begin(), pe=MD->param_end();
1403 pi != pe; ++pi, ++parm_idx) {
1404 const ParmVarDecl *pd = *pi;
1405 if (pd->hasAttr<NSConsumedAttr>())
1406 Template->addArg(AF, parm_idx, DecRefMsg);
1407 else if (pd->hasAttr<CFConsumedAttr>()) {
1408 Template->addArg(AF, parm_idx, DecRef);
1409 } else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
1410 QualType PointeeTy = pd->getType()->getPointeeType();
1411 if (!PointeeTy.isNull())
1412 if (coreFoundation::isCFObjectRef(PointeeTy))
1413 Template->addArg(AF, parm_idx, RetainedOutParameter);
1414 } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
1415 QualType PointeeTy = pd->getType()->getPointeeType();
1416 if (!PointeeTy.isNull())
1417 if (coreFoundation::isCFObjectRef(PointeeTy))
1418 Template->addArg(AF, parm_idx, UnretainedOutParameter);
1422 QualType RetTy = MD->getReturnType();
1423 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD))
1424 Template->setRetEffect(*RetE);
1427 const RetainSummary *
1428 RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD,
1429 Selector S, QualType RetTy) {
1430 // Any special effects?
1431 ArgEffect ReceiverEff = DoNothing;
1432 RetEffect ResultEff = RetEffect::MakeNoRet();
1434 // Check the method family, and apply any default annotations.
1435 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) {
1437 case OMF_initialize:
1438 case OMF_performSelector:
1439 // Assume all Objective-C methods follow Cocoa Memory Management rules.
1440 // FIXME: Does the non-threaded performSelector family really belong here?
1441 // The selector could be, say, @selector(copy).
1442 if (cocoa::isCocoaObjectRef(RetTy))
1443 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC);
1444 else if (coreFoundation::isCFObjectRef(RetTy)) {
1445 // ObjCMethodDecl currently doesn't consider CF objects as valid return
1446 // values for alloc, new, copy, or mutableCopy, so we have to
1447 // double-check with the selector. This is ugly, but there aren't that
1448 // many Objective-C methods that return CF objects, right?
1450 switch (S.getMethodFamily()) {
1454 case OMF_mutableCopy:
1455 ResultEff = RetEffect::MakeOwned(RetEffect::CF);
1458 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
1462 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
1467 ResultEff = ObjCInitRetE;
1468 ReceiverEff = DecRefMsg;
1473 case OMF_mutableCopy:
1474 if (cocoa::isCocoaObjectRef(RetTy))
1475 ResultEff = ObjCAllocRetE;
1476 else if (coreFoundation::isCFObjectRef(RetTy))
1477 ResultEff = RetEffect::MakeOwned(RetEffect::CF);
1479 case OMF_autorelease:
1480 ReceiverEff = Autorelease;
1483 ReceiverEff = IncRefMsg;
1486 ReceiverEff = DecRefMsg;
1489 ReceiverEff = Dealloc;
1492 // -self is handled specially by the ExprEngine to propagate the receiver.
1494 case OMF_retainCount:
1496 // These methods don't return objects.
1500 // If one of the arguments in the selector has the keyword 'delegate' we
1501 // should stop tracking the reference count for the receiver. This is
1502 // because the reference count is quite possibly handled by a delegate
1504 if (S.isKeywordSelector()) {
1505 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) {
1506 StringRef Slot = S.getNameForSlot(i);
1507 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) {
1508 if (ResultEff == ObjCInitRetE)
1509 ResultEff = RetEffect::MakeNoRetHard();
1511 ReceiverEff = StopTrackingHard;
1516 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing &&
1517 ResultEff.getKind() == RetEffect::NoRet)
1518 return getDefaultSummary();
1520 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape);
1523 const RetainSummary *
1524 RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg,
1525 ProgramStateRef State) {
1526 const ObjCInterfaceDecl *ReceiverClass = nullptr;
1528 // We do better tracking of the type of the object than the core ExprEngine.
1529 // See if we have its type in our private state.
1530 // FIXME: Eventually replace the use of state->get<RefBindings> with
1531 // a generic API for reasoning about the Objective-C types of symbolic
1533 SVal ReceiverV = Msg.getReceiverSVal();
1534 if (SymbolRef Sym = ReceiverV.getAsLocSymbol())
1535 if (const RefVal *T = getRefBinding(State, Sym))
1536 if (const ObjCObjectPointerType *PT =
1537 T->getType()->getAs<ObjCObjectPointerType>())
1538 ReceiverClass = PT->getInterfaceDecl();
1540 // If we don't know what kind of object this is, fall back to its static type.
1542 ReceiverClass = Msg.getReceiverInterface();
1544 // FIXME: The receiver could be a reference to a class, meaning that
1545 // we should use the class method.
1546 // id x = [NSObject class];
1547 // [x performSelector:... withObject:... afterDelay:...];
1548 Selector S = Msg.getSelector();
1549 const ObjCMethodDecl *Method = Msg.getDecl();
1550 if (!Method && ReceiverClass)
1551 Method = ReceiverClass->getInstanceMethod(S);
1553 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(),
1554 ObjCMethodSummaries);
1557 const RetainSummary *
1558 RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
1559 const ObjCMethodDecl *MD, QualType RetTy,
1560 ObjCMethodSummariesTy &CachedSummaries) {
1562 // Look up a summary in our summary cache.
1563 const RetainSummary *Summ = CachedSummaries.find(ID, S);
1566 Summ = getStandardMethodSummary(MD, S, RetTy);
1568 // Annotations override defaults.
1569 updateSummaryFromAnnotations(Summ, MD);
1571 // Memoize the summary.
1572 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ;
1578 void RetainSummaryManager::InitializeClassMethodSummaries() {
1579 assert(ScratchArgs.isEmpty());
1580 // Create the [NSAssertionHandler currentHander] summary.
1581 addClassMethSummary("NSAssertionHandler", "currentHandler",
1582 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC)));
1584 // Create the [NSAutoreleasePool addObject:] summary.
1585 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease);
1586 addClassMethSummary("NSAutoreleasePool", "addObject",
1587 getPersistentSummary(RetEffect::MakeNoRet(),
1588 DoNothing, Autorelease));
1591 void RetainSummaryManager::InitializeMethodSummaries() {
1593 assert (ScratchArgs.isEmpty());
1595 // Create the "init" selector. It just acts as a pass-through for the
1597 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg);
1598 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm);
1600 // awakeAfterUsingCoder: behaves basically like an 'init' method. It
1601 // claims the receiver and returns a retained object.
1602 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx),
1605 // The next methods are allocators.
1606 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE);
1607 const RetainSummary *CFAllocSumm =
1608 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF));
1610 // Create the "retain" selector.
1611 RetEffect NoRet = RetEffect::MakeNoRet();
1612 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg);
1613 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ);
1615 // Create the "release" selector.
1616 Summ = getPersistentSummary(NoRet, DecRefMsg);
1617 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ);
1619 // Create the -dealloc summary.
1620 Summ = getPersistentSummary(NoRet, Dealloc);
1621 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ);
1623 // Create the "autorelease" selector.
1624 Summ = getPersistentSummary(NoRet, Autorelease);
1625 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ);
1627 // For NSWindow, allocated objects are (initially) self-owned.
1628 // FIXME: For now we opt for false negatives with NSWindow, as these objects
1629 // self-own themselves. However, they only do this once they are displayed.
1630 // Thus, we need to track an NSWindow's display status.
1631 // This is tracked in <rdar://problem/6062711>.
1632 // See also http://llvm.org/bugs/show_bug.cgi?id=3714.
1633 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(),
1637 addClassMethSummary("NSWindow", "alloc", NoTrackYet);
1639 // For NSPanel (which subclasses NSWindow), allocated objects are not
1641 // FIXME: For now we don't track NSPanels. object for the same reason
1642 // as for NSWindow objects.
1643 addClassMethSummary("NSPanel", "alloc", NoTrackYet);
1645 // For NSNull, objects returned by +null are singletons that ignore
1646 // retain/release semantics. Just don't track them.
1647 // <rdar://problem/12858915>
1648 addClassMethSummary("NSNull", "null", NoTrackYet);
1650 // Don't track allocated autorelease pools, as it is okay to prematurely
1652 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet);
1653 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false);
1654 addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet);
1656 // Create summaries QCRenderer/QCView -createSnapShotImageOfType:
1657 addInstMethSummary("QCRenderer", AllocSumm, "createSnapshotImageOfType");
1658 addInstMethSummary("QCView", AllocSumm, "createSnapshotImageOfType");
1660 // Create summaries for CIContext, 'createCGImage' and
1661 // 'createCGLayerWithSize'. These objects are CF objects, and are not
1662 // automatically garbage collected.
1663 addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect");
1664 addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect",
1665 "format", "colorSpace");
1666 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", "info");
1669 //===----------------------------------------------------------------------===//
1671 //===----------------------------------------------------------------------===//
1673 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *>
1676 //===-------------===//
1677 // Bug Descriptions. //
1678 //===-------------===//
1680 class CFRefBug : public BugType {
1682 CFRefBug(const CheckerBase *checker, StringRef name)
1683 : BugType(checker, name, categories::MemoryCoreFoundationObjectiveC) {}
1687 // FIXME: Eventually remove.
1688 virtual const char *getDescription() const = 0;
1690 virtual bool isLeak() const { return false; }
1693 class UseAfterRelease : public CFRefBug {
1695 UseAfterRelease(const CheckerBase *checker)
1696 : CFRefBug(checker, "Use-after-release") {}
1698 const char *getDescription() const override {
1699 return "Reference-counted object is used after it is released";
1703 class BadRelease : public CFRefBug {
1705 BadRelease(const CheckerBase *checker) : CFRefBug(checker, "Bad release") {}
1707 const char *getDescription() const override {
1708 return "Incorrect decrement of the reference count of an object that is "
1709 "not owned at this point by the caller";
1713 class DeallocGC : public CFRefBug {
1715 DeallocGC(const CheckerBase *checker)
1716 : CFRefBug(checker, "-dealloc called while using garbage collection") {}
1718 const char *getDescription() const override {
1719 return "-dealloc called while using garbage collection";
1723 class DeallocNotOwned : public CFRefBug {
1725 DeallocNotOwned(const CheckerBase *checker)
1726 : CFRefBug(checker, "-dealloc sent to non-exclusively owned object") {}
1728 const char *getDescription() const override {
1729 return "-dealloc sent to object that may be referenced elsewhere";
1733 class OverAutorelease : public CFRefBug {
1735 OverAutorelease(const CheckerBase *checker)
1736 : CFRefBug(checker, "Object autoreleased too many times") {}
1738 const char *getDescription() const override {
1739 return "Object autoreleased too many times";
1743 class ReturnedNotOwnedForOwned : public CFRefBug {
1745 ReturnedNotOwnedForOwned(const CheckerBase *checker)
1746 : CFRefBug(checker, "Method should return an owned object") {}
1748 const char *getDescription() const override {
1749 return "Object with a +0 retain count returned to caller where a +1 "
1750 "(owning) retain count is expected";
1754 class Leak : public CFRefBug {
1756 Leak(const CheckerBase *checker, StringRef name) : CFRefBug(checker, name) {
1757 // Leaks should not be reported if they are post-dominated by a sink.
1758 setSuppressOnSink(true);
1761 const char *getDescription() const override { return ""; }
1763 bool isLeak() const override { return true; }
1770 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> {
1773 const SummaryLogTy &SummaryLog;
1777 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log)
1778 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {}
1780 void Profile(llvm::FoldingSetNodeID &ID) const override {
1786 std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N,
1787 const ExplodedNode *PrevN,
1788 BugReporterContext &BRC,
1789 BugReport &BR) override;
1791 std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
1792 const ExplodedNode *N,
1793 BugReport &BR) override;
1796 class CFRefLeakReportVisitor : public CFRefReportVisitor {
1798 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled,
1799 const SummaryLogTy &log)
1800 : CFRefReportVisitor(sym, GCEnabled, log) {}
1802 std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
1803 const ExplodedNode *N,
1804 BugReport &BR) override;
1806 std::unique_ptr<BugReporterVisitor> clone() const override {
1807 // The curiously-recurring template pattern only works for one level of
1808 // subclassing. Rather than make a new template base for
1809 // CFRefReportVisitor, we simply override clone() to do the right thing.
1810 // This could be trouble someday if BugReporterVisitorImpl is ever
1811 // used for something else besides a convenient implementation of clone().
1812 return llvm::make_unique<CFRefLeakReportVisitor>(*this);
1816 class CFRefReport : public BugReport {
1817 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled);
1820 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1821 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1822 bool registerVisitor = true)
1823 : BugReport(D, D.getDescription(), n) {
1824 if (registerVisitor)
1825 addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
1826 addGCModeDescription(LOpts, GCEnabled);
1829 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1830 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1832 : BugReport(D, D.getDescription(), endText, n) {
1833 addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
1834 addGCModeDescription(LOpts, GCEnabled);
1837 llvm::iterator_range<ranges_iterator> getRanges() override {
1838 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType());
1839 if (!BugTy.isLeak())
1840 return BugReport::getRanges();
1841 return llvm::make_range(ranges_iterator(), ranges_iterator());
1845 class CFRefLeakReport : public CFRefReport {
1846 const MemRegion* AllocBinding;
1848 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1849 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1850 CheckerContext &Ctx,
1851 bool IncludeAllocationLine);
1853 PathDiagnosticLocation getLocation(const SourceManager &SM) const override {
1854 assert(Location.isValid());
1858 } // end anonymous namespace
1860 void CFRefReport::addGCModeDescription(const LangOptions &LOpts,
1862 const char *GCModeDescription = nullptr;
1864 switch (LOpts.getGC()) {
1865 case LangOptions::GCOnly:
1867 GCModeDescription = "Code is compiled to only use garbage collection";
1870 case LangOptions::NonGC:
1872 GCModeDescription = "Code is compiled to use reference counts";
1875 case LangOptions::HybridGC:
1877 GCModeDescription = "Code is compiled to use either garbage collection "
1878 "(GC) or reference counts (non-GC). The bug occurs "
1882 GCModeDescription = "Code is compiled to use either garbage collection "
1883 "(GC) or reference counts (non-GC). The bug occurs "
1889 assert(GCModeDescription && "invalid/unknown GC mode");
1890 addExtraText(GCModeDescription);
1893 static bool isNumericLiteralExpression(const Expr *E) {
1894 // FIXME: This set of cases was copied from SemaExprObjC.
1895 return isa<IntegerLiteral>(E) ||
1896 isa<CharacterLiteral>(E) ||
1897 isa<FloatingLiteral>(E) ||
1898 isa<ObjCBoolLiteralExpr>(E) ||
1899 isa<CXXBoolLiteralExpr>(E);
1902 /// Returns true if this stack frame is for an Objective-C method that is a
1903 /// property getter or setter whose body has been synthesized by the analyzer.
1904 static bool isSynthesizedAccessor(const StackFrameContext *SFC) {
1905 auto Method = dyn_cast_or_null<ObjCMethodDecl>(SFC->getDecl());
1906 if (!Method || !Method->isPropertyAccessor())
1909 return SFC->getAnalysisDeclContext()->isBodyAutosynthesized();
1912 std::shared_ptr<PathDiagnosticPiece>
1913 CFRefReportVisitor::VisitNode(const ExplodedNode *N, const ExplodedNode *PrevN,
1914 BugReporterContext &BRC, BugReport &BR) {
1915 // FIXME: We will eventually need to handle non-statement-based events
1916 // (__attribute__((cleanup))).
1917 if (!N->getLocation().getAs<StmtPoint>())
1920 // Check if the type state has changed.
1921 ProgramStateRef PrevSt = PrevN->getState();
1922 ProgramStateRef CurrSt = N->getState();
1923 const LocationContext *LCtx = N->getLocationContext();
1925 const RefVal* CurrT = getRefBinding(CurrSt, Sym);
1926 if (!CurrT) return nullptr;
1928 const RefVal &CurrV = *CurrT;
1929 const RefVal *PrevT = getRefBinding(PrevSt, Sym);
1931 // Create a string buffer to constain all the useful things we want
1932 // to tell the user.
1934 llvm::raw_string_ostream os(sbuf);
1936 // This is the allocation site since the previous node had no bindings
1939 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
1941 if (isa<ObjCIvarRefExpr>(S) &&
1942 isSynthesizedAccessor(LCtx->getCurrentStackFrame())) {
1943 S = LCtx->getCurrentStackFrame()->getCallSite();
1946 if (isa<ObjCArrayLiteral>(S)) {
1947 os << "NSArray literal is an object with a +0 retain count";
1949 else if (isa<ObjCDictionaryLiteral>(S)) {
1950 os << "NSDictionary literal is an object with a +0 retain count";
1952 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) {
1953 if (isNumericLiteralExpression(BL->getSubExpr()))
1954 os << "NSNumber literal is an object with a +0 retain count";
1956 const ObjCInterfaceDecl *BoxClass = nullptr;
1957 if (const ObjCMethodDecl *Method = BL->getBoxingMethod())
1958 BoxClass = Method->getClassInterface();
1960 // We should always be able to find the boxing class interface,
1961 // but consider this future-proofing.
1963 os << *BoxClass << " b";
1967 os << "oxed expression produces an object with a +0 retain count";
1970 else if (isa<ObjCIvarRefExpr>(S)) {
1971 os << "Object loaded from instance variable";
1974 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
1975 // Get the name of the callee (if it is available).
1976 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx);
1977 if (const FunctionDecl *FD = X.getAsFunctionDecl())
1978 os << "Call to function '" << *FD << '\'';
1980 os << "function call";
1983 assert(isa<ObjCMessageExpr>(S));
1984 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager();
1985 CallEventRef<ObjCMethodCall> Call
1986 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx);
1988 switch (Call->getMessageKind()) {
1992 case OCM_PropertyAccess:
2001 if (CurrV.getObjKind() == RetEffect::CF) {
2002 if (Sym->getType().isNull()) {
2003 os << " returns a Core Foundation object with a ";
2005 os << " returns a Core Foundation object of type "
2006 << Sym->getType().getAsString() << " with a ";
2010 assert (CurrV.getObjKind() == RetEffect::ObjC);
2011 QualType T = Sym->getType();
2012 if (T.isNull() || !isa<ObjCObjectPointerType>(T)) {
2013 os << " returns an Objective-C object with a ";
2015 const ObjCObjectPointerType *PT = cast<ObjCObjectPointerType>(T);
2016 os << " returns an instance of "
2017 << PT->getPointeeType().getAsString() << " with a ";
2021 if (CurrV.isOwned()) {
2022 os << "+1 retain count";
2025 assert(CurrV.getObjKind() == RetEffect::CF);
2027 "Core Foundation objects are not automatically garbage collected.";
2031 assert (CurrV.isNotOwned());
2032 os << "+0 retain count";
2036 PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
2037 N->getLocationContext());
2038 return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
2041 // Gather up the effects that were performed on the object at this
2043 SmallVector<ArgEffect, 2> AEffects;
2045 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N);
2046 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) {
2047 // We only have summaries attached to nodes after evaluating CallExpr and
2048 // ObjCMessageExprs.
2049 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2051 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
2052 // Iterate through the parameter expressions and see if the symbol
2053 // was ever passed as an argument.
2056 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end();
2057 AI!=AE; ++AI, ++i) {
2059 // Retrieve the value of the argument. Is it the symbol
2060 // we are interested in?
2061 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym)
2064 // We have an argument. Get the effect!
2065 AEffects.push_back(Summ->getArg(i));
2068 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) {
2069 if (const Expr *receiver = ME->getInstanceReceiver())
2070 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx)
2071 .getAsLocSymbol() == Sym) {
2072 // The symbol we are tracking is the receiver.
2073 AEffects.push_back(Summ->getReceiverEffect());
2079 // Get the previous type state.
2080 RefVal PrevV = *PrevT;
2082 // Specially handle -dealloc.
2083 if (!GCEnabled && std::find(AEffects.begin(), AEffects.end(), Dealloc) !=
2085 // Determine if the object's reference count was pushed to zero.
2086 assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
2087 // We may not have transitioned to 'release' if we hit an error.
2088 // This case is handled elsewhere.
2089 if (CurrV.getKind() == RefVal::Released) {
2090 assert(CurrV.getCombinedCounts() == 0);
2091 os << "Object released by directly sending the '-dealloc' message";
2096 // Specially handle CFMakeCollectable and friends.
2097 if (std::find(AEffects.begin(), AEffects.end(), MakeCollectable) !=
2099 // Get the name of the function.
2100 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2102 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx);
2103 const FunctionDecl *FD = X.getAsFunctionDecl();
2106 // Determine if the object's reference count was pushed to zero.
2107 assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
2109 os << "In GC mode a call to '" << *FD
2110 << "' decrements an object's retain count and registers the "
2111 "object with the garbage collector. ";
2113 if (CurrV.getKind() == RefVal::Released) {
2114 assert(CurrV.getCount() == 0);
2115 os << "Since it now has a 0 retain count the object can be "
2116 "automatically collected by the garbage collector.";
2119 os << "An object must have a 0 retain count to be garbage collected. "
2120 "After this call its retain count is +" << CurrV.getCount()
2124 os << "When GC is not enabled a call to '" << *FD
2125 << "' has no effect on its argument.";
2127 // Nothing more to say.
2131 // Determine if the typestate has changed.
2132 if (!PrevV.hasSameState(CurrV))
2133 switch (CurrV.getKind()) {
2135 case RefVal::NotOwned:
2136 if (PrevV.getCount() == CurrV.getCount()) {
2137 // Did an autorelease message get sent?
2138 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount())
2141 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount());
2142 os << "Object autoreleased";
2146 if (PrevV.getCount() > CurrV.getCount())
2147 os << "Reference count decremented.";
2149 os << "Reference count incremented.";
2151 if (unsigned Count = CurrV.getCount())
2152 os << " The object now has a +" << Count << " retain count.";
2154 if (PrevV.getKind() == RefVal::Released) {
2155 assert(GCEnabled && CurrV.getCount() > 0);
2156 os << " The object is not eligible for garbage collection until "
2157 "the retain count reaches 0 again.";
2162 case RefVal::Released:
2163 if (CurrV.getIvarAccessHistory() ==
2164 RefVal::IvarAccessHistory::ReleasedAfterDirectAccess &&
2165 CurrV.getIvarAccessHistory() != PrevV.getIvarAccessHistory()) {
2166 os << "Strong instance variable relinquished. ";
2168 os << "Object released.";
2171 case RefVal::ReturnedOwned:
2172 // Autoreleases can be applied after marking a node ReturnedOwned.
2173 if (CurrV.getAutoreleaseCount())
2176 os << "Object returned to caller as an owning reference (single "
2177 "retain count transferred to caller)";
2180 case RefVal::ReturnedNotOwned:
2181 os << "Object returned to caller with a +0 retain count";
2188 // Emit any remaining diagnostics for the argument effects (if any).
2189 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(),
2190 E=AEffects.end(); I != E; ++I) {
2192 // A bunch of things have alternate behavior under GC.
2197 os << "In GC mode an 'autorelease' has no effect.";
2200 os << "In GC mode the 'retain' message has no effect.";
2203 os << "In GC mode the 'release' message has no effect.";
2209 if (os.str().empty())
2210 return nullptr; // We have nothing to say!
2212 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2213 PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
2214 N->getLocationContext());
2215 auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
2217 // Add the range by scanning the children of the statement for any bindings
2219 for (const Stmt *Child : S->children())
2220 if (const Expr *Exp = dyn_cast_or_null<Expr>(Child))
2221 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) {
2222 P->addRange(Exp->getSourceRange());
2226 return std::move(P);
2230 // Find the first node in the current function context that referred to the
2231 // tracked symbol and the memory location that value was stored to. Note, the
2232 // value is only reported if the allocation occurred in the same function as
2233 // the leak. The function can also return a location context, which should be
2234 // treated as interesting.
2235 struct AllocationInfo {
2236 const ExplodedNode* N;
2238 const LocationContext *InterestingMethodContext;
2239 AllocationInfo(const ExplodedNode *InN,
2240 const MemRegion *InR,
2241 const LocationContext *InInterestingMethodContext) :
2242 N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {}
2244 } // end anonymous namespace
2246 static AllocationInfo
2247 GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N,
2249 const ExplodedNode *AllocationNode = N;
2250 const ExplodedNode *AllocationNodeInCurrentOrParentContext = N;
2251 const MemRegion *FirstBinding = nullptr;
2252 const LocationContext *LeakContext = N->getLocationContext();
2254 // The location context of the init method called on the leaked object, if
2256 const LocationContext *InitMethodContext = nullptr;
2259 ProgramStateRef St = N->getState();
2260 const LocationContext *NContext = N->getLocationContext();
2262 if (!getRefBinding(St, Sym))
2265 StoreManager::FindUniqueBinding FB(Sym);
2266 StateMgr.iterBindings(St, FB);
2269 const MemRegion *R = FB.getRegion();
2270 const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>();
2271 // Do not show local variables belonging to a function other than
2272 // where the error is reported.
2273 if (!VR || VR->getStackFrame() == LeakContext->getCurrentStackFrame())
2277 // AllocationNode is the last node in which the symbol was tracked.
2280 // AllocationNodeInCurrentContext, is the last node in the current or
2281 // parent context in which the symbol was tracked.
2283 // Note that the allocation site might be in the parent conext. For example,
2284 // the case where an allocation happens in a block that captures a reference
2285 // to it and that reference is overwritten/dropped by another call to
2287 if (NContext == LeakContext || NContext->isParentOf(LeakContext))
2288 AllocationNodeInCurrentOrParentContext = N;
2290 // Find the last init that was called on the given symbol and store the
2291 // init method's location context.
2292 if (!InitMethodContext)
2293 if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) {
2294 const Stmt *CE = CEP->getCallExpr();
2295 if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) {
2296 const Stmt *RecExpr = ME->getInstanceReceiver();
2298 SVal RecV = St->getSVal(RecExpr, NContext);
2299 if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym)
2300 InitMethodContext = CEP->getCalleeContext();
2305 N = N->pred_empty() ? nullptr : *(N->pred_begin());
2308 // If we are reporting a leak of the object that was allocated with alloc,
2309 // mark its init method as interesting.
2310 const LocationContext *InterestingMethodContext = nullptr;
2311 if (InitMethodContext) {
2312 const ProgramPoint AllocPP = AllocationNode->getLocation();
2313 if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>())
2314 if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>())
2315 if (ME->getMethodFamily() == OMF_alloc)
2316 InterestingMethodContext = InitMethodContext;
2319 // If allocation happened in a function different from the leak node context,
2320 // do not report the binding.
2321 assert(N && "Could not find allocation node");
2322 if (N->getLocationContext() != LeakContext) {
2323 FirstBinding = nullptr;
2326 return AllocationInfo(AllocationNodeInCurrentOrParentContext,
2328 InterestingMethodContext);
2331 std::unique_ptr<PathDiagnosticPiece>
2332 CFRefReportVisitor::getEndPath(BugReporterContext &BRC,
2333 const ExplodedNode *EndN, BugReport &BR) {
2334 BR.markInteresting(Sym);
2335 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR);
2338 std::unique_ptr<PathDiagnosticPiece>
2339 CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
2340 const ExplodedNode *EndN, BugReport &BR) {
2342 // Tell the BugReporterContext to report cases when the tracked symbol is
2343 // assigned to different variables, etc.
2344 BR.markInteresting(Sym);
2346 // We are reporting a leak. Walk up the graph to get to the first node where
2347 // the symbol appeared, and also get the first VarDecl that tracked object
2349 AllocationInfo AllocI =
2350 GetAllocationSite(BRC.getStateManager(), EndN, Sym);
2352 const MemRegion* FirstBinding = AllocI.R;
2353 BR.markInteresting(AllocI.InterestingMethodContext);
2355 SourceManager& SM = BRC.getSourceManager();
2357 // Compute an actual location for the leak. Sometimes a leak doesn't
2358 // occur at an actual statement (e.g., transition between blocks; end
2359 // of function) so we need to walk the graph and compute a real location.
2360 const ExplodedNode *LeakN = EndN;
2361 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM);
2364 llvm::raw_string_ostream os(sbuf);
2366 os << "Object leaked: ";
2369 os << "object allocated and stored into '"
2370 << FirstBinding->getString() << '\'';
2373 os << "allocated object";
2375 // Get the retain count.
2376 const RefVal* RV = getRefBinding(EndN->getState(), Sym);
2379 if (RV->getKind() == RefVal::ErrorLeakReturned) {
2380 // FIXME: Per comments in rdar://6320065, "create" only applies to CF
2381 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership
2382 // to the caller for NS objects.
2383 const Decl *D = &EndN->getCodeDecl();
2385 os << (isa<ObjCMethodDecl>(D) ? " is returned from a method "
2386 : " is returned from a function ");
2388 if (D->hasAttr<CFReturnsNotRetainedAttr>())
2389 os << "that is annotated as CF_RETURNS_NOT_RETAINED";
2390 else if (D->hasAttr<NSReturnsNotRetainedAttr>())
2391 os << "that is annotated as NS_RETURNS_NOT_RETAINED";
2393 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
2394 if (BRC.getASTContext().getLangOpts().ObjCAutoRefCount) {
2395 os << "managed by Automatic Reference Counting";
2397 os << "whose name ('" << MD->getSelector().getAsString()
2398 << "') does not start with "
2399 "'copy', 'mutableCopy', 'alloc' or 'new'."
2400 " This violates the naming convention rules"
2401 " given in the Memory Management Guide for Cocoa";
2405 const FunctionDecl *FD = cast<FunctionDecl>(D);
2406 os << "whose name ('" << *FD
2407 << "') does not contain 'Copy' or 'Create'. This violates the naming"
2408 " convention rules given in the Memory Management Guide for Core"
2413 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) {
2414 const ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl());
2415 os << " and returned from method '" << MD.getSelector().getAsString()
2416 << "' is potentially leaked when using garbage collection. Callers "
2417 "of this method do not expect a returned object with a +1 retain "
2418 "count since they expect the object to be managed by the garbage "
2422 os << " is not referenced later in this execution path and has a retain "
2423 "count of +" << RV->getCount();
2425 return llvm::make_unique<PathDiagnosticEventPiece>(L, os.str());
2428 CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts,
2429 bool GCEnabled, const SummaryLogTy &Log,
2430 ExplodedNode *n, SymbolRef sym,
2431 CheckerContext &Ctx,
2432 bool IncludeAllocationLine)
2433 : CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) {
2435 // Most bug reports are cached at the location where they occurred.
2436 // With leaks, we want to unique them by the location where they were
2437 // allocated, and only report a single path. To do this, we need to find
2438 // the allocation site of a piece of tracked memory, which we do via a
2439 // call to GetAllocationSite. This will walk the ExplodedGraph backwards.
2440 // Note that this is *not* the trimmed graph; we are guaranteed, however,
2441 // that all ancestor nodes that represent the allocation site have the
2442 // same SourceLocation.
2443 const ExplodedNode *AllocNode = nullptr;
2445 const SourceManager& SMgr = Ctx.getSourceManager();
2447 AllocationInfo AllocI =
2448 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym);
2450 AllocNode = AllocI.N;
2451 AllocBinding = AllocI.R;
2452 markInteresting(AllocI.InterestingMethodContext);
2454 // Get the SourceLocation for the allocation site.
2455 // FIXME: This will crash the analyzer if an allocation comes from an
2456 // implicit call (ex: a destructor call).
2457 // (Currently there are no such allocations in Cocoa, though.)
2458 const Stmt *AllocStmt = PathDiagnosticLocation::getStmt(AllocNode);
2459 assert(AllocStmt && "Cannot find allocation statement");
2461 PathDiagnosticLocation AllocLocation =
2462 PathDiagnosticLocation::createBegin(AllocStmt, SMgr,
2463 AllocNode->getLocationContext());
2464 Location = AllocLocation;
2466 // Set uniqieing info, which will be used for unique the bug reports. The
2467 // leaks should be uniqued on the allocation site.
2468 UniqueingLocation = AllocLocation;
2469 UniqueingDecl = AllocNode->getLocationContext()->getDecl();
2471 // Fill in the description of the bug.
2472 Description.clear();
2473 llvm::raw_string_ostream os(Description);
2474 os << "Potential leak ";
2476 os << "(when using garbage collection) ";
2477 os << "of an object";
2480 os << " stored into '" << AllocBinding->getString() << '\'';
2481 if (IncludeAllocationLine) {
2482 FullSourceLoc SL(AllocStmt->getLocStart(), Ctx.getSourceManager());
2483 os << " (allocated on line " << SL.getSpellingLineNumber() << ")";
2487 addVisitor(llvm::make_unique<CFRefLeakReportVisitor>(sym, GCEnabled, Log));
2490 //===----------------------------------------------------------------------===//
2491 // Main checker logic.
2492 //===----------------------------------------------------------------------===//
2495 class RetainCountChecker
2496 : public Checker< check::Bind,
2500 check::PostStmt<BlockExpr>,
2501 check::PostStmt<CastExpr>,
2502 check::PostStmt<ObjCArrayLiteral>,
2503 check::PostStmt<ObjCDictionaryLiteral>,
2504 check::PostStmt<ObjCBoxedExpr>,
2505 check::PostStmt<ObjCIvarRefExpr>,
2507 check::PreStmt<ReturnStmt>,
2508 check::RegionChanges,
2511 mutable std::unique_ptr<CFRefBug> useAfterRelease, releaseNotOwned;
2512 mutable std::unique_ptr<CFRefBug> deallocGC, deallocNotOwned;
2513 mutable std::unique_ptr<CFRefBug> overAutorelease, returnNotOwnedForOwned;
2514 mutable std::unique_ptr<CFRefBug> leakWithinFunction, leakAtReturn;
2515 mutable std::unique_ptr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC;
2517 typedef llvm::DenseMap<SymbolRef, const CheckerProgramPointTag *> SymbolTagMap;
2519 // This map is only used to ensure proper deletion of any allocated tags.
2520 mutable SymbolTagMap DeadSymbolTags;
2522 mutable std::unique_ptr<RetainSummaryManager> Summaries;
2523 mutable std::unique_ptr<RetainSummaryManager> SummariesGC;
2524 mutable SummaryLogTy SummaryLog;
2525 mutable bool ShouldResetSummaryLog;
2527 /// Optional setting to indicate if leak reports should include
2528 /// the allocation line.
2529 mutable bool IncludeAllocationLine;
2532 RetainCountChecker(AnalyzerOptions &AO)
2533 : ShouldResetSummaryLog(false),
2534 IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {}
2536 ~RetainCountChecker() override { DeleteContainerSeconds(DeadSymbolTags); }
2538 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR,
2539 ExprEngine &Eng) const {
2540 // FIXME: This is a hack to make sure the summary log gets cleared between
2541 // analyses of different code bodies.
2543 // Why is this necessary? Because a checker's lifetime is tied to a
2544 // translation unit, but an ExplodedGraph's lifetime is just a code body.
2545 // Once in a blue moon, a new ExplodedNode will have the same address as an
2546 // old one with an associated summary, and the bug report visitor gets very
2547 // confused. (To make things worse, the summary lifetime is currently also
2548 // tied to a code body, so we get a crash instead of incorrect results.)
2550 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph
2551 // changes, things will start going wrong again. Really the lifetime of this
2552 // log needs to be tied to either the specific nodes in it or the entire
2553 // ExplodedGraph, not to a specific part of the code being analyzed.
2555 // (Also, having stateful local data means that the same checker can't be
2556 // used from multiple threads, but a lot of checkers have incorrect
2557 // assumptions about that anyway. So that wasn't a priority at the time of
2560 // This happens at the end of analysis, but bug reports are emitted /after/
2561 // this point. So we can't just clear the summary log now. Instead, we mark
2562 // that the next time we access the summary log, it should be cleared.
2564 // If we never reset the summary log during /this/ code body analysis,
2565 // there were no new summaries. There might still have been summaries from
2566 // the /last/ analysis, so clear them out to make sure the bug report
2567 // visitors don't get confused.
2568 if (ShouldResetSummaryLog)
2571 ShouldResetSummaryLog = !SummaryLog.empty();
2574 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts,
2575 bool GCEnabled) const {
2577 if (!leakWithinFunctionGC)
2578 leakWithinFunctionGC.reset(new Leak(this, "Leak of object when using "
2579 "garbage collection"));
2580 return leakWithinFunctionGC.get();
2582 if (!leakWithinFunction) {
2583 if (LOpts.getGC() == LangOptions::HybridGC) {
2584 leakWithinFunction.reset(new Leak(this,
2585 "Leak of object when not using "
2586 "garbage collection (GC) in "
2587 "dual GC/non-GC code"));
2589 leakWithinFunction.reset(new Leak(this, "Leak"));
2592 return leakWithinFunction.get();
2596 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const {
2598 if (!leakAtReturnGC)
2599 leakAtReturnGC.reset(new Leak(this,
2600 "Leak of returned object when using "
2601 "garbage collection"));
2602 return leakAtReturnGC.get();
2604 if (!leakAtReturn) {
2605 if (LOpts.getGC() == LangOptions::HybridGC) {
2606 leakAtReturn.reset(new Leak(this,
2607 "Leak of returned object when not using "
2608 "garbage collection (GC) in dual "
2611 leakAtReturn.reset(new Leak(this, "Leak of returned object"));
2614 return leakAtReturn.get();
2618 RetainSummaryManager &getSummaryManager(ASTContext &Ctx,
2619 bool GCEnabled) const {
2620 // FIXME: We don't support ARC being turned on and off during one analysis.
2621 // (nor, for that matter, do we support changing ASTContexts)
2622 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount;
2625 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled));
2627 assert(SummariesGC->isARCEnabled() == ARCEnabled);
2628 return *SummariesGC;
2631 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled));
2633 assert(Summaries->isARCEnabled() == ARCEnabled);
2638 RetainSummaryManager &getSummaryManager(CheckerContext &C) const {
2639 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled());
2642 void printState(raw_ostream &Out, ProgramStateRef State,
2643 const char *NL, const char *Sep) const override;
2645 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const;
2646 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
2647 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const;
2649 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const;
2650 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const;
2651 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const;
2653 void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const;
2655 void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
2657 void checkSummary(const RetainSummary &Summ, const CallEvent &Call,
2658 CheckerContext &C) const;
2660 void processSummaryOfInlined(const RetainSummary &Summ,
2661 const CallEvent &Call,
2662 CheckerContext &C) const;
2664 bool evalCall(const CallExpr *CE, CheckerContext &C) const;
2666 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
2667 bool Assumption) const;
2670 checkRegionChanges(ProgramStateRef state,
2671 const InvalidatedSymbols *invalidated,
2672 ArrayRef<const MemRegion *> ExplicitRegions,
2673 ArrayRef<const MemRegion *> Regions,
2674 const LocationContext* LCtx,
2675 const CallEvent *Call) const;
2677 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
2678 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C,
2679 ExplodedNode *Pred, RetEffect RE, RefVal X,
2680 SymbolRef Sym, ProgramStateRef state) const;
2682 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
2683 void checkEndFunction(CheckerContext &C) const;
2685 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym,
2686 RefVal V, ArgEffect E, RefVal::Kind &hasErr,
2687 CheckerContext &C) const;
2689 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange,
2690 RefVal::Kind ErrorKind, SymbolRef Sym,
2691 CheckerContext &C) const;
2693 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const;
2695 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const;
2697 ProgramStateRef handleSymbolDeath(ProgramStateRef state,
2698 SymbolRef sid, RefVal V,
2699 SmallVectorImpl<SymbolRef> &Leaked) const;
2702 handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred,
2703 const ProgramPointTag *Tag, CheckerContext &Ctx,
2704 SymbolRef Sym, RefVal V) const;
2706 ExplodedNode *processLeaks(ProgramStateRef state,
2707 SmallVectorImpl<SymbolRef> &Leaked,
2708 CheckerContext &Ctx,
2709 ExplodedNode *Pred = nullptr) const;
2711 } // end anonymous namespace
2714 class StopTrackingCallback final : public SymbolVisitor {
2715 ProgramStateRef state;
2717 StopTrackingCallback(ProgramStateRef st) : state(std::move(st)) {}
2718 ProgramStateRef getState() const { return state; }
2720 bool VisitSymbol(SymbolRef sym) override {
2721 state = state->remove<RefBindings>(sym);
2725 } // end anonymous namespace
2727 //===----------------------------------------------------------------------===//
2728 // Handle statements that may have an effect on refcounts.
2729 //===----------------------------------------------------------------------===//
2731 void RetainCountChecker::checkPostStmt(const BlockExpr *BE,
2732 CheckerContext &C) const {
2734 // Scan the BlockDecRefExprs for any object the retain count checker
2736 if (!BE->getBlockDecl()->hasCaptures())
2739 ProgramStateRef state = C.getState();
2740 const BlockDataRegion *R =
2741 cast<BlockDataRegion>(state->getSVal(BE,
2742 C.getLocationContext()).getAsRegion());
2744 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
2745 E = R->referenced_vars_end();
2750 // FIXME: For now we invalidate the tracking of all symbols passed to blocks
2751 // via captured variables, even though captured variables result in a copy
2752 // and in implicit increment/decrement of a retain count.
2753 SmallVector<const MemRegion*, 10> Regions;
2754 const LocationContext *LC = C.getLocationContext();
2755 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager();
2757 for ( ; I != E; ++I) {
2758 const VarRegion *VR = I.getCapturedRegion();
2759 if (VR->getSuperRegion() == R) {
2760 VR = MemMgr.getVarRegion(VR->getDecl(), LC);
2762 Regions.push_back(VR);
2766 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(),
2767 Regions.data() + Regions.size()).getState();
2768 C.addTransition(state);
2771 void RetainCountChecker::checkPostStmt(const CastExpr *CE,
2772 CheckerContext &C) const {
2773 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE);
2777 ArgEffect AE = IncRef;
2779 switch (BE->getBridgeKind()) {
2780 case clang::OBC_Bridge:
2783 case clang::OBC_BridgeRetained:
2786 case clang::OBC_BridgeTransfer:
2787 AE = DecRefBridgedTransferred;
2791 ProgramStateRef state = C.getState();
2792 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol();
2795 const RefVal* T = getRefBinding(state, Sym);
2799 RefVal::Kind hasErr = (RefVal::Kind) 0;
2800 state = updateSymbol(state, Sym, *T, AE, hasErr, C);
2803 // FIXME: If we get an error during a bridge cast, should we report it?
2807 C.addTransition(state);
2810 void RetainCountChecker::processObjCLiterals(CheckerContext &C,
2811 const Expr *Ex) const {
2812 ProgramStateRef state = C.getState();
2813 const ExplodedNode *pred = C.getPredecessor();
2814 for (const Stmt *Child : Ex->children()) {
2815 SVal V = state->getSVal(Child, pred->getLocationContext());
2816 if (SymbolRef sym = V.getAsSymbol())
2817 if (const RefVal* T = getRefBinding(state, sym)) {
2818 RefVal::Kind hasErr = (RefVal::Kind) 0;
2819 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C);
2821 processNonLeakError(state, Child->getSourceRange(), hasErr, sym, C);
2827 // Return the object as autoreleased.
2828 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC);
2830 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) {
2831 QualType ResultTy = Ex->getType();
2832 state = setRefBinding(state, sym,
2833 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
2836 C.addTransition(state);
2839 void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL,
2840 CheckerContext &C) const {
2841 // Apply the 'MayEscape' to all values.
2842 processObjCLiterals(C, AL);
2845 void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL,
2846 CheckerContext &C) const {
2847 // Apply the 'MayEscape' to all keys and values.
2848 processObjCLiterals(C, DL);
2851 void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex,
2852 CheckerContext &C) const {
2853 const ExplodedNode *Pred = C.getPredecessor();
2854 const LocationContext *LCtx = Pred->getLocationContext();
2855 ProgramStateRef State = Pred->getState();
2857 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) {
2858 QualType ResultTy = Ex->getType();
2859 State = setRefBinding(State, Sym,
2860 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
2863 C.addTransition(State);
2866 void RetainCountChecker::checkPostStmt(const ObjCIvarRefExpr *IRE,
2867 CheckerContext &C) const {
2868 Optional<Loc> IVarLoc = C.getSVal(IRE).getAs<Loc>();
2872 ProgramStateRef State = C.getState();
2873 SymbolRef Sym = State->getSVal(*IVarLoc).getAsSymbol();
2874 if (!Sym || !dyn_cast_or_null<ObjCIvarRegion>(Sym->getOriginRegion()))
2877 // Accessing an ivar directly is unusual. If we've done that, be more
2878 // forgiving about what the surrounding code is allowed to do.
2880 QualType Ty = Sym->getType();
2881 RetEffect::ObjKind Kind;
2882 if (Ty->isObjCRetainableType())
2883 Kind = RetEffect::ObjC;
2884 else if (coreFoundation::isCFObjectRef(Ty))
2885 Kind = RetEffect::CF;
2889 // If the value is already known to be nil, don't bother tracking it.
2890 ConstraintManager &CMgr = State->getConstraintManager();
2891 if (CMgr.isNull(State, Sym).isConstrainedTrue())
2894 if (const RefVal *RV = getRefBinding(State, Sym)) {
2895 // If we've seen this symbol before, or we're only seeing it now because
2896 // of something the analyzer has synthesized, don't do anything.
2897 if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None ||
2898 isSynthesizedAccessor(C.getStackFrame())) {
2902 // Note that this value has been loaded from an ivar.
2903 C.addTransition(setRefBinding(State, Sym, RV->withIvarAccess()));
2907 RefVal PlusZero = RefVal::makeNotOwned(Kind, Ty);
2909 // In a synthesized accessor, the effective retain count is +0.
2910 if (isSynthesizedAccessor(C.getStackFrame())) {
2911 C.addTransition(setRefBinding(State, Sym, PlusZero));
2915 State = setRefBinding(State, Sym, PlusZero.withIvarAccess());
2916 C.addTransition(State);
2919 void RetainCountChecker::checkPostCall(const CallEvent &Call,
2920 CheckerContext &C) const {
2921 RetainSummaryManager &Summaries = getSummaryManager(C);
2922 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState());
2925 processSummaryOfInlined(*Summ, Call, C);
2928 checkSummary(*Summ, Call, C);
2931 /// GetReturnType - Used to get the return type of a message expression or
2932 /// function call with the intention of affixing that type to a tracked symbol.
2933 /// While the return type can be queried directly from RetEx, when
2934 /// invoking class methods we augment to the return type to be that of
2935 /// a pointer to the class (as opposed it just being id).
2936 // FIXME: We may be able to do this with related result types instead.
2937 // This function is probably overestimating.
2938 static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) {
2939 QualType RetTy = RetE->getType();
2940 // If RetE is not a message expression just return its type.
2941 // If RetE is a message expression, return its types if it is something
2942 /// more specific than id.
2943 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE))
2944 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>())
2945 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() ||
2946 PT->isObjCClassType()) {
2947 // At this point we know the return type of the message expression is
2948 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this
2949 // is a call to a class method whose type we can resolve. In such
2950 // cases, promote the return type to XXX* (where XXX is the class).
2951 const ObjCInterfaceDecl *D = ME->getReceiverInterface();
2953 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D));
2959 // We don't always get the exact modeling of the function with regards to the
2960 // retain count checker even when the function is inlined. For example, we need
2961 // to stop tracking the symbols which were marked with StopTrackingHard.
2962 void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ,
2963 const CallEvent &CallOrMsg,
2964 CheckerContext &C) const {
2965 ProgramStateRef state = C.getState();
2967 // Evaluate the effect of the arguments.
2968 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
2969 if (Summ.getArg(idx) == StopTrackingHard) {
2970 SVal V = CallOrMsg.getArgSVal(idx);
2971 if (SymbolRef Sym = V.getAsLocSymbol()) {
2972 state = removeRefBinding(state, Sym);
2977 // Evaluate the effect on the message receiver.
2978 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
2979 if (MsgInvocation) {
2980 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
2981 if (Summ.getReceiverEffect() == StopTrackingHard) {
2982 state = removeRefBinding(state, Sym);
2987 // Consult the summary for the return value.
2988 RetEffect RE = Summ.getRetEffect();
2989 if (RE.getKind() == RetEffect::NoRetHard) {
2990 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
2992 state = removeRefBinding(state, Sym);
2995 C.addTransition(state);
2998 static ProgramStateRef updateOutParameter(ProgramStateRef State,
3001 auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion());
3005 QualType PointeeTy = ArgRegion->getValueType();
3006 if (!coreFoundation::isCFObjectRef(PointeeTy))
3009 SVal PointeeVal = State->getSVal(ArgRegion);
3010 SymbolRef Pointee = PointeeVal.getAsLocSymbol();
3015 case UnretainedOutParameter:
3016 State = setRefBinding(State, Pointee,
3017 RefVal::makeNotOwned(RetEffect::CF, PointeeTy));
3019 case RetainedOutParameter:
3020 // Do nothing. Retained out parameters will either point to a +1 reference
3021 // or NULL, but the way you check for failure differs depending on the API.
3022 // Consequently, we don't have a good way to track them yet.
3026 llvm_unreachable("only for out parameters");
3032 void RetainCountChecker::checkSummary(const RetainSummary &Summ,
3033 const CallEvent &CallOrMsg,
3034 CheckerContext &C) const {
3035 ProgramStateRef state = C.getState();
3037 // Evaluate the effect of the arguments.
3038 RefVal::Kind hasErr = (RefVal::Kind) 0;
3039 SourceRange ErrorRange;
3040 SymbolRef ErrorSym = nullptr;
3042 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
3043 SVal V = CallOrMsg.getArgSVal(idx);
3045 ArgEffect Effect = Summ.getArg(idx);
3046 if (Effect == RetainedOutParameter || Effect == UnretainedOutParameter) {
3047 state = updateOutParameter(state, V, Effect);
3048 } else if (SymbolRef Sym = V.getAsLocSymbol()) {
3049 if (const RefVal *T = getRefBinding(state, Sym)) {
3050 state = updateSymbol(state, Sym, *T, Effect, hasErr, C);
3052 ErrorRange = CallOrMsg.getArgSourceRange(idx);
3060 // Evaluate the effect on the message receiver.
3061 bool ReceiverIsTracked = false;
3063 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
3064 if (MsgInvocation) {
3065 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
3066 if (const RefVal *T = getRefBinding(state, Sym)) {
3067 ReceiverIsTracked = true;
3068 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(),
3071 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange();
3079 // Process any errors.
3081 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C);
3085 // Consult the summary for the return value.
3086 RetEffect RE = Summ.getRetEffect();
3088 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) {
3089 if (ReceiverIsTracked)
3090 RE = getSummaryManager(C).getObjAllocRetEffect();
3092 RE = RetEffect::MakeNoRet();
3095 switch (RE.getKind()) {
3097 llvm_unreachable("Unhandled RetEffect.");
3099 case RetEffect::NoRet:
3100 case RetEffect::NoRetHard:
3101 // No work necessary.
3104 case RetEffect::OwnedSymbol: {
3105 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
3109 // Use the result type from the CallEvent as it automatically adjusts
3110 // for methods/functions that return references.
3111 QualType ResultTy = CallOrMsg.getResultType();
3112 state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(),
3115 // FIXME: Add a flag to the checker where allocations are assumed to
3120 case RetEffect::GCNotOwnedSymbol:
3121 case RetEffect::NotOwnedSymbol: {
3122 const Expr *Ex = CallOrMsg.getOriginExpr();
3123 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
3127 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *.
3128 QualType ResultTy = GetReturnType(Ex, C.getASTContext());
3129 state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(),
3135 // This check is actually necessary; otherwise the statement builder thinks
3136 // we've hit a previously-found path.
3137 // Normally addTransition takes care of this, but we want the node pointer.
3138 ExplodedNode *NewNode;
3139 if (state == C.getState()) {
3140 NewNode = C.getPredecessor();
3142 NewNode = C.addTransition(state);
3145 // Annotate the node with summary we used.
3147 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary.
3148 if (ShouldResetSummaryLog) {
3150 ShouldResetSummaryLog = false;
3152 SummaryLog[NewNode] = &Summ;
3157 RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym,
3158 RefVal V, ArgEffect E, RefVal::Kind &hasErr,
3159 CheckerContext &C) const {
3160 // In GC mode [... release] and [... retain] do nothing.
3161 // In ARC mode they shouldn't exist at all, but we just ignore them.
3162 bool IgnoreRetainMsg = C.isObjCGCEnabled();
3163 if (!IgnoreRetainMsg)
3164 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount;
3170 E = IgnoreRetainMsg ? DoNothing : IncRef;
3173 E = IgnoreRetainMsg ? DoNothing : DecRef;
3175 case DecRefMsgAndStopTrackingHard:
3176 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard;
3178 case MakeCollectable:
3179 E = C.isObjCGCEnabled() ? DecRef : DoNothing;
3183 // Handle all use-after-releases.
3184 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) {
3185 V = V ^ RefVal::ErrorUseAfterRelease;
3186 hasErr = V.getKind();
3187 return setRefBinding(state, sym, V);
3193 case MakeCollectable:
3194 case DecRefMsgAndStopTrackingHard:
3195 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted");
3197 case UnretainedOutParameter:
3198 case RetainedOutParameter:
3199 llvm_unreachable("Applies to pointer-to-pointer parameters, which should "
3200 "not have ref state.");
3203 // Any use of -dealloc in GC is *bad*.
3204 if (C.isObjCGCEnabled()) {
3205 V = V ^ RefVal::ErrorDeallocGC;
3206 hasErr = V.getKind();
3210 switch (V.getKind()) {
3212 llvm_unreachable("Invalid RefVal state for an explicit dealloc.");
3214 // The object immediately transitions to the released state.
3215 V = V ^ RefVal::Released;
3217 return setRefBinding(state, sym, V);
3218 case RefVal::NotOwned:
3219 V = V ^ RefVal::ErrorDeallocNotOwned;
3220 hasErr = V.getKind();
3226 if (V.getKind() == RefVal::Owned) {
3227 V = V ^ RefVal::NotOwned;
3237 if (C.isObjCGCEnabled())
3239 // Update the autorelease counts.
3240 V = V.autorelease();
3244 case StopTrackingHard:
3245 return removeRefBinding(state, sym);
3248 switch (V.getKind()) {
3250 llvm_unreachable("Invalid RefVal state for a retain.");
3252 case RefVal::NotOwned:
3255 case RefVal::Released:
3256 // Non-GC cases are handled above.
3257 assert(C.isObjCGCEnabled());
3258 V = (V ^ RefVal::Owned) + 1;
3264 case DecRefBridgedTransferred:
3265 case DecRefAndStopTrackingHard:
3266 switch (V.getKind()) {
3268 // case 'RefVal::Released' handled above.
3269 llvm_unreachable("Invalid RefVal state for a release.");
3272 assert(V.getCount() > 0);
3273 if (V.getCount() == 1) {
3274 if (E == DecRefBridgedTransferred ||
3275 V.getIvarAccessHistory() ==
3276 RefVal::IvarAccessHistory::AccessedDirectly)
3277 V = V ^ RefVal::NotOwned;
3279 V = V ^ RefVal::Released;
3280 } else if (E == DecRefAndStopTrackingHard) {
3281 return removeRefBinding(state, sym);
3287 case RefVal::NotOwned:
3288 if (V.getCount() > 0) {
3289 if (E == DecRefAndStopTrackingHard)
3290 return removeRefBinding(state, sym);
3292 } else if (V.getIvarAccessHistory() ==
3293 RefVal::IvarAccessHistory::AccessedDirectly) {
3294 // Assume that the instance variable was holding on the object at
3295 // +1, and we just didn't know.
3296 if (E == DecRefAndStopTrackingHard)
3297 return removeRefBinding(state, sym);
3298 V = V.releaseViaIvar() ^ RefVal::Released;
3300 V = V ^ RefVal::ErrorReleaseNotOwned;
3301 hasErr = V.getKind();
3305 case RefVal::Released:
3306 // Non-GC cases are handled above.
3307 assert(C.isObjCGCEnabled());
3308 V = V ^ RefVal::ErrorUseAfterRelease;
3309 hasErr = V.getKind();
3314 return setRefBinding(state, sym, V);
3317 void RetainCountChecker::processNonLeakError(ProgramStateRef St,
3318 SourceRange ErrorRange,
3319 RefVal::Kind ErrorKind,
3321 CheckerContext &C) const {
3322 // HACK: Ignore retain-count issues on values accessed through ivars,
3323 // because of cases like this:
3324 // [_contentView retain];
3325 // [_contentView removeFromSuperview];
3326 // [self addSubview:_contentView]; // invalidates 'self'
3327 // [_contentView release];
3328 if (const RefVal *RV = getRefBinding(St, Sym))
3329 if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3332 ExplodedNode *N = C.generateErrorNode(St);
3337 switch (ErrorKind) {
3339 llvm_unreachable("Unhandled error.");
3340 case RefVal::ErrorUseAfterRelease:
3341 if (!useAfterRelease)
3342 useAfterRelease.reset(new UseAfterRelease(this));
3343 BT = useAfterRelease.get();
3345 case RefVal::ErrorReleaseNotOwned:
3346 if (!releaseNotOwned)
3347 releaseNotOwned.reset(new BadRelease(this));
3348 BT = releaseNotOwned.get();
3350 case RefVal::ErrorDeallocGC:
3352 deallocGC.reset(new DeallocGC(this));
3353 BT = deallocGC.get();
3355 case RefVal::ErrorDeallocNotOwned:
3356 if (!deallocNotOwned)
3357 deallocNotOwned.reset(new DeallocNotOwned(this));
3358 BT = deallocNotOwned.get();
3363 auto report = std::unique_ptr<BugReport>(
3364 new CFRefReport(*BT, C.getASTContext().getLangOpts(), C.isObjCGCEnabled(),
3365 SummaryLog, N, Sym));
3366 report->addRange(ErrorRange);
3367 C.emitReport(std::move(report));
3370 //===----------------------------------------------------------------------===//
3371 // Handle the return values of retain-count-related functions.
3372 //===----------------------------------------------------------------------===//
3374 bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
3375 // Get the callee. We're only interested in simple C functions.
3376 ProgramStateRef state = C.getState();
3377 const FunctionDecl *FD = C.getCalleeDecl(CE);
3381 IdentifierInfo *II = FD->getIdentifier();
3385 // For now, we're only handling the functions that return aliases of their
3386 // arguments: CFRetain and CFMakeCollectable (and their families).
3387 // Eventually we should add other functions we can model entirely,
3388 // such as CFRelease, which don't invalidate their arguments or globals.
3389 if (CE->getNumArgs() != 1)
3392 // Get the name of the function.
3393 StringRef FName = II->getName();
3394 FName = FName.substr(FName.find_first_not_of('_'));
3396 // See if it's one of the specific functions we know how to eval.
3397 bool canEval = false;
3398 // See if the function has 'rc_ownership_trusted_implementation'
3399 // annotate attribute. If it does, we will not inline it.
3400 bool hasTrustedImplementationAnnotation = false;
3402 QualType ResultTy = CE->getCallReturnType(C.getASTContext());
3403 if (ResultTy->isObjCIdType()) {
3404 // Handle: id NSMakeCollectable(CFTypeRef)
3405 canEval = II->isStr("NSMakeCollectable");
3406 } else if (ResultTy->isPointerType()) {
3407 // Handle: (CF|CG|CV)Retain
3409 // CFMakeCollectable
3410 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist).
3411 if (cocoa::isRefType(ResultTy, "CF", FName) ||
3412 cocoa::isRefType(ResultTy, "CG", FName) ||
3413 cocoa::isRefType(ResultTy, "CV", FName)) {
3414 canEval = isRetain(FD, FName) || isAutorelease(FD, FName) ||
3415 isMakeCollectable(FD, FName);
3417 if (FD->getDefinition()) {
3418 canEval = isTrustedReferenceCountImplementation(FD->getDefinition());
3419 hasTrustedImplementationAnnotation = canEval;
3427 // Bind the return value.
3428 const LocationContext *LCtx = C.getLocationContext();
3429 SVal RetVal = state->getSVal(CE->getArg(0), LCtx);
3430 if (RetVal.isUnknown() ||
3431 (hasTrustedImplementationAnnotation && !ResultTy.isNull())) {
3432 // If the receiver is unknown or the function has
3433 // 'rc_ownership_trusted_implementation' annotate attribute, conjure a
3435 SValBuilder &SVB = C.getSValBuilder();
3436 RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, ResultTy, C.blockCount());
3438 state = state->BindExpr(CE, LCtx, RetVal, false);
3440 // FIXME: This should not be necessary, but otherwise the argument seems to be
3441 // considered alive during the next statement.
3442 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) {
3443 // Save the refcount status of the argument.
3444 SymbolRef Sym = RetVal.getAsLocSymbol();
3445 const RefVal *Binding = nullptr;
3447 Binding = getRefBinding(state, Sym);
3449 // Invalidate the argument region.
3450 state = state->invalidateRegions(
3451 ArgRegion, CE, C.blockCount(), LCtx,
3452 /*CausesPointerEscape*/ hasTrustedImplementationAnnotation);
3454 // Restore the refcount status of the argument.
3456 state = setRefBinding(state, Sym, *Binding);
3459 C.addTransition(state);
3463 //===----------------------------------------------------------------------===//
3464 // Handle return statements.
3465 //===----------------------------------------------------------------------===//
3467 void RetainCountChecker::checkPreStmt(const ReturnStmt *S,
3468 CheckerContext &C) const {
3470 // Only adjust the reference count if this is the top-level call frame,
3471 // and not the result of inlining. In the future, we should do
3472 // better checking even for inlined calls, and see if they match
3473 // with their expected semantics (e.g., the method should return a retained
3475 if (!C.inTopFrame())
3478 const Expr *RetE = S->getRetValue();
3482 ProgramStateRef state = C.getState();
3484 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol();
3488 // Get the reference count binding (if any).
3489 const RefVal *T = getRefBinding(state, Sym);
3493 // Change the reference count.
3496 switch (X.getKind()) {
3497 case RefVal::Owned: {
3498 unsigned cnt = X.getCount();
3500 X.setCount(cnt - 1);
3501 X = X ^ RefVal::ReturnedOwned;
3505 case RefVal::NotOwned: {
3506 unsigned cnt = X.getCount();
3508 X.setCount(cnt - 1);
3509 X = X ^ RefVal::ReturnedOwned;
3512 X = X ^ RefVal::ReturnedNotOwned;
3521 // Update the binding.
3522 state = setRefBinding(state, Sym, X);
3523 ExplodedNode *Pred = C.addTransition(state);
3525 // At this point we have updated the state properly.
3526 // Everything after this is merely checking to see if the return value has
3527 // been over- or under-retained.
3529 // Did we cache out?
3533 // Update the autorelease counts.
3534 static CheckerProgramPointTag AutoreleaseTag(this, "Autorelease");
3535 state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X);
3537 // Did we cache out?
3541 // Get the updated binding.
3542 T = getRefBinding(state, Sym);
3546 // Consult the summary of the enclosing method.
3547 RetainSummaryManager &Summaries = getSummaryManager(C);
3548 const Decl *CD = &Pred->getCodeDecl();
3549 RetEffect RE = RetEffect::MakeNoRet();
3551 // FIXME: What is the convention for blocks? Is there one?
3552 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) {
3553 const RetainSummary *Summ = Summaries.getMethodSummary(MD);
3554 RE = Summ->getRetEffect();
3555 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) {
3556 if (!isa<CXXMethodDecl>(FD)) {
3557 const RetainSummary *Summ = Summaries.getFunctionSummary(FD);
3558 RE = Summ->getRetEffect();
3562 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state);
3565 void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S,
3568 RetEffect RE, RefVal X,
3570 ProgramStateRef state) const {
3571 // HACK: Ignore retain-count issues on values accessed through ivars,
3572 // because of cases like this:
3573 // [_contentView retain];
3574 // [_contentView removeFromSuperview];
3575 // [self addSubview:_contentView]; // invalidates 'self'
3576 // [_contentView release];
3577 if (X.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3580 // Any leaks or other errors?
3581 if (X.isReturnedOwned() && X.getCount() == 0) {
3582 if (RE.getKind() != RetEffect::NoRet) {
3583 bool hasError = false;
3584 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) {
3585 // Things are more complicated with garbage collection. If the
3586 // returned object is suppose to be an Objective-C object, we have
3587 // a leak (as the caller expects a GC'ed object) because no
3588 // method should return ownership unless it returns a CF object.
3590 X = X ^ RefVal::ErrorGCLeakReturned;
3592 else if (!RE.isOwned()) {
3593 // Either we are using GC and the returned object is a CF type
3594 // or we aren't using GC. In either case, we expect that the
3595 // enclosing method is expected to return ownership.
3597 X = X ^ RefVal::ErrorLeakReturned;
3601 // Generate an error node.
3602 state = setRefBinding(state, Sym, X);
3604 static CheckerProgramPointTag ReturnOwnLeakTag(this, "ReturnsOwnLeak");
3605 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag);
3607 const LangOptions &LOpts = C.getASTContext().getLangOpts();
3608 bool GCEnabled = C.isObjCGCEnabled();
3609 C.emitReport(std::unique_ptr<BugReport>(new CFRefLeakReport(
3610 *getLeakAtReturnBug(LOpts, GCEnabled), LOpts, GCEnabled,
3611 SummaryLog, N, Sym, C, IncludeAllocationLine)));
3615 } else if (X.isReturnedNotOwned()) {
3617 if (X.getIvarAccessHistory() ==
3618 RefVal::IvarAccessHistory::AccessedDirectly) {
3619 // Assume the method was trying to transfer a +1 reference from a
3620 // strong ivar to the caller.
3621 state = setRefBinding(state, Sym,
3622 X.releaseViaIvar() ^ RefVal::ReturnedOwned);
3624 // Trying to return a not owned object to a caller expecting an
3626 state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned);
3628 static CheckerProgramPointTag
3629 ReturnNotOwnedTag(this, "ReturnNotOwnedForOwned");
3631 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag);
3633 if (!returnNotOwnedForOwned)
3634 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned(this));
3636 C.emitReport(std::unique_ptr<BugReport>(new CFRefReport(
3637 *returnNotOwnedForOwned, C.getASTContext().getLangOpts(),
3638 C.isObjCGCEnabled(), SummaryLog, N, Sym)));
3645 //===----------------------------------------------------------------------===//
3646 // Check various ways a symbol can be invalidated.
3647 //===----------------------------------------------------------------------===//
3649 void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S,
3650 CheckerContext &C) const {
3651 // Are we storing to something that causes the value to "escape"?
3652 bool escapes = true;
3654 // A value escapes in three possible cases (this may change):
3656 // (1) we are binding to something that is not a memory region.
3657 // (2) we are binding to a memregion that does not have stack storage
3658 // (3) we are binding to a memregion with stack storage that the store
3659 // does not understand.
3660 ProgramStateRef state = C.getState();
3662 if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) {
3663 escapes = !regionLoc->getRegion()->hasStackStorage();
3666 // To test (3), generate a new state with the binding added. If it is
3667 // the same state, then it escapes (since the store cannot represent
3669 // Do this only if we know that the store is not supposed to generate the
3671 SVal StoredVal = state->getSVal(regionLoc->getRegion());
3672 if (StoredVal != val)
3673 escapes = (state == (state->bindLoc(*regionLoc, val, C.getLocationContext())));
3676 // Case 4: We do not currently model what happens when a symbol is
3677 // assigned to a struct field, so be conservative here and let the symbol
3678 // go. TODO: This could definitely be improved upon.
3679 escapes = !isa<VarRegion>(regionLoc->getRegion());
3683 // If we are storing the value into an auto function scope variable annotated
3684 // with (__attribute__((cleanup))), stop tracking the value to avoid leak
3686 if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) {
3687 const VarDecl *VD = LVR->getDecl();
3688 if (VD->hasAttr<CleanupAttr>()) {
3693 // If our store can represent the binding and we aren't storing to something
3694 // that doesn't have local storage then just return and have the simulation
3695 // state continue as is.
3699 // Otherwise, find all symbols referenced by 'val' that we are tracking
3700 // and stop tracking them.
3701 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState();
3702 C.addTransition(state);
3705 ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state,
3707 bool Assumption) const {
3708 // FIXME: We may add to the interface of evalAssume the list of symbols
3709 // whose assumptions have changed. For now we just iterate through the
3710 // bindings and check if any of the tracked symbols are NULL. This isn't
3711 // too bad since the number of symbols we will track in practice are
3712 // probably small and evalAssume is only called at branches and a few
3714 RefBindingsTy B = state->get<RefBindings>();
3719 bool changed = false;
3720 RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>();
3722 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
3723 // Check if the symbol is null stop tracking the symbol.
3724 ConstraintManager &CMgr = state->getConstraintManager();
3725 ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey());
3726 if (AllocFailed.isConstrainedTrue()) {
3728 B = RefBFactory.remove(B, I.getKey());
3733 state = state->set<RefBindings>(B);
3739 RetainCountChecker::checkRegionChanges(ProgramStateRef state,
3740 const InvalidatedSymbols *invalidated,
3741 ArrayRef<const MemRegion *> ExplicitRegions,
3742 ArrayRef<const MemRegion *> Regions,
3743 const LocationContext *LCtx,
3744 const CallEvent *Call) const {
3748 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols;
3749 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
3750 E = ExplicitRegions.end(); I != E; ++I) {
3751 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>())
3752 WhitelistedSymbols.insert(SR->getSymbol());
3755 for (InvalidatedSymbols::const_iterator I=invalidated->begin(),
3756 E = invalidated->end(); I!=E; ++I) {
3758 if (WhitelistedSymbols.count(sym))
3760 // Remove any existing reference-count binding.
3761 state = removeRefBinding(state, sym);
3766 //===----------------------------------------------------------------------===//
3767 // Handle dead symbols and end-of-path.
3768 //===----------------------------------------------------------------------===//
3771 RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state,
3773 const ProgramPointTag *Tag,
3774 CheckerContext &Ctx,
3775 SymbolRef Sym, RefVal V) const {
3776 unsigned ACnt = V.getAutoreleaseCount();
3778 // No autorelease counts? Nothing to be done.
3782 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?");
3783 unsigned Cnt = V.getCount();
3785 // FIXME: Handle sending 'autorelease' to already released object.
3787 if (V.getKind() == RefVal::ReturnedOwned)
3790 // If we would over-release here, but we know the value came from an ivar,
3791 // assume it was a strong ivar that's just been relinquished.
3793 V.getIvarAccessHistory() == RefVal::IvarAccessHistory::AccessedDirectly) {
3794 V = V.releaseViaIvar();
3801 if (V.getKind() == RefVal::ReturnedOwned)
3802 V = V ^ RefVal::ReturnedNotOwned;
3804 V = V ^ RefVal::NotOwned;
3806 V.setCount(V.getCount() - ACnt);
3807 V.setAutoreleaseCount(0);
3809 return setRefBinding(state, Sym, V);
3812 // HACK: Ignore retain-count issues on values accessed through ivars,
3813 // because of cases like this:
3814 // [_contentView retain];
3815 // [_contentView removeFromSuperview];
3816 // [self addSubview:_contentView]; // invalidates 'self'
3817 // [_contentView release];
3818 if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3821 // Woah! More autorelease counts then retain counts left.
3823 V = V ^ RefVal::ErrorOverAutorelease;
3824 state = setRefBinding(state, Sym, V);
3826 ExplodedNode *N = Ctx.generateSink(state, Pred, Tag);
3828 SmallString<128> sbuf;
3829 llvm::raw_svector_ostream os(sbuf);
3830 os << "Object was autoreleased ";
3831 if (V.getAutoreleaseCount() > 1)
3832 os << V.getAutoreleaseCount() << " times but the object ";
3835 os << "has a +" << V.getCount() << " retain count";
3837 if (!overAutorelease)
3838 overAutorelease.reset(new OverAutorelease(this));
3840 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
3841 Ctx.emitReport(std::unique_ptr<BugReport>(
3842 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false,
3843 SummaryLog, N, Sym, os.str())));
3850 RetainCountChecker::handleSymbolDeath(ProgramStateRef state,
3851 SymbolRef sid, RefVal V,
3852 SmallVectorImpl<SymbolRef> &Leaked) const {
3855 // HACK: Ignore retain-count issues on values accessed through ivars,
3856 // because of cases like this:
3857 // [_contentView retain];
3858 // [_contentView removeFromSuperview];
3859 // [self addSubview:_contentView]; // invalidates 'self'
3860 // [_contentView release];
3861 if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3863 else if (V.isOwned())
3865 else if (V.isNotOwned() || V.isReturnedOwned())
3866 hasLeak = (V.getCount() > 0);
3871 return removeRefBinding(state, sid);
3873 Leaked.push_back(sid);
3874 return setRefBinding(state, sid, V ^ RefVal::ErrorLeak);
3878 RetainCountChecker::processLeaks(ProgramStateRef state,
3879 SmallVectorImpl<SymbolRef> &Leaked,
3880 CheckerContext &Ctx,
3881 ExplodedNode *Pred) const {
3882 // Generate an intermediate node representing the leak point.
3883 ExplodedNode *N = Ctx.addTransition(state, Pred);
3886 for (SmallVectorImpl<SymbolRef>::iterator
3887 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) {
3889 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
3890 bool GCEnabled = Ctx.isObjCGCEnabled();
3891 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled)
3892 : getLeakAtReturnBug(LOpts, GCEnabled);
3893 assert(BT && "BugType not initialized.");
3895 Ctx.emitReport(std::unique_ptr<BugReport>(
3896 new CFRefLeakReport(*BT, LOpts, GCEnabled, SummaryLog, N, *I, Ctx,
3897 IncludeAllocationLine)));
3904 void RetainCountChecker::checkEndFunction(CheckerContext &Ctx) const {
3905 ProgramStateRef state = Ctx.getState();
3906 RefBindingsTy B = state->get<RefBindings>();
3907 ExplodedNode *Pred = Ctx.getPredecessor();
3909 // Don't process anything within synthesized bodies.
3910 const LocationContext *LCtx = Pred->getLocationContext();
3911 if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) {
3912 assert(!LCtx->inTopFrame());
3916 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
3917 state = handleAutoreleaseCounts(state, Pred, /*Tag=*/nullptr, Ctx,
3918 I->first, I->second);
3923 // If the current LocationContext has a parent, don't check for leaks.
3924 // We will do that later.
3925 // FIXME: we should instead check for imbalances of the retain/releases,
3926 // and suggest annotations.
3927 if (LCtx->getParent())
3930 B = state->get<RefBindings>();
3931 SmallVector<SymbolRef, 10> Leaked;
3933 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I)
3934 state = handleSymbolDeath(state, I->first, I->second, Leaked);
3936 processLeaks(state, Leaked, Ctx, Pred);
3939 const ProgramPointTag *
3940 RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const {
3941 const CheckerProgramPointTag *&tag = DeadSymbolTags[sym];
3943 SmallString<64> buf;
3944 llvm::raw_svector_ostream out(buf);
3945 out << "Dead Symbol : ";
3946 sym->dumpToStream(out);
3947 tag = new CheckerProgramPointTag(this, out.str());
3952 void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper,
3953 CheckerContext &C) const {
3954 ExplodedNode *Pred = C.getPredecessor();
3956 ProgramStateRef state = C.getState();
3957 RefBindingsTy B = state->get<RefBindings>();
3958 SmallVector<SymbolRef, 10> Leaked;
3960 // Update counts from autorelease pools
3961 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
3962 E = SymReaper.dead_end(); I != E; ++I) {
3964 if (const RefVal *T = B.lookup(Sym)){
3965 // Use the symbol as the tag.
3966 // FIXME: This might not be as unique as we would like.
3967 const ProgramPointTag *Tag = getDeadSymbolTag(Sym);
3968 state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T);
3972 // Fetch the new reference count from the state, and use it to handle
3974 state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked);
3978 if (Leaked.empty()) {
3979 C.addTransition(state);
3983 Pred = processLeaks(state, Leaked, C, Pred);
3985 // Did we cache out?
3989 // Now generate a new node that nukes the old bindings.
3990 // The only bindings left at this point are the leaked symbols.
3991 RefBindingsTy::Factory &F = state->get_context<RefBindings>();
3992 B = state->get<RefBindings>();
3994 for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(),
3997 B = F.remove(B, *I);
3999 state = state->set<RefBindings>(B);
4000 C.addTransition(state, Pred);
4003 void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State,
4004 const char *NL, const char *Sep) const {
4006 RefBindingsTy B = State->get<RefBindings>();
4013 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
4014 Out << I->first << " : ";
4015 I->second.print(Out);
4020 //===----------------------------------------------------------------------===//
4021 // Checker registration.
4022 //===----------------------------------------------------------------------===//
4024 void ento::registerRetainCountChecker(CheckerManager &Mgr) {
4025 Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions());
4028 //===----------------------------------------------------------------------===//
4029 // Implementation of the CallEffects API.
4030 //===----------------------------------------------------------------------===//
4034 namespace objc_retain {
4036 // This is a bit gross, but it allows us to populate CallEffects without
4037 // creating a bunch of accessors. This kind is very localized, so the
4038 // damage of this macro is limited.
4039 #define createCallEffect(D, KIND)\
4040 ASTContext &Ctx = D->getASTContext();\
4041 LangOptions L = Ctx.getLangOpts();\
4042 RetainSummaryManager M(Ctx, L.GCOnly, L.ObjCAutoRefCount);\
4043 const RetainSummary *S = M.get ## KIND ## Summary(D);\
4044 CallEffects CE(S->getRetEffect());\
4045 CE.Receiver = S->getReceiverEffect();\
4046 unsigned N = D->param_size();\
4047 for (unsigned i = 0; i < N; ++i) {\
4048 CE.Args.push_back(S->getArg(i));\
4051 CallEffects CallEffects::getEffect(const ObjCMethodDecl *MD) {
4052 createCallEffect(MD, Method);
4056 CallEffects CallEffects::getEffect(const FunctionDecl *FD) {
4057 createCallEffect(FD, Function);
4061 #undef createCallEffect
4063 } // end namespace objc_retain
4064 } // end namespace ento
4065 } // end namespace clang