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 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy &Summaries,
707 const RetainSummary *Summ, va_list argp) {
708 Selector S = getKeywordSelector(Ctx, argp);
709 Summaries[ObjCSummaryKey(ClsII, S)] = Summ;
712 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) {
714 va_start(argp, Summ);
715 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp);
719 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) {
721 va_start(argp, Summ);
722 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp);
726 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) {
728 va_start(argp, Summ);
729 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp);
735 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC)
737 GCEnabled(gcenabled),
739 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()),
740 ObjCAllocRetE(gcenabled
741 ? RetEffect::MakeGCNotOwned()
742 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
743 : RetEffect::MakeOwned(RetEffect::ObjC))),
744 ObjCInitRetE(gcenabled
745 ? RetEffect::MakeGCNotOwned()
746 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC)
747 : RetEffect::MakeOwnedWhenTrackedReceiver())) {
748 InitializeClassMethodSummaries();
749 InitializeMethodSummaries();
752 const RetainSummary *getSummary(const CallEvent &Call,
753 ProgramStateRef State = nullptr);
755 const RetainSummary *getFunctionSummary(const FunctionDecl *FD);
757 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
758 const ObjCMethodDecl *MD,
760 ObjCMethodSummariesTy &CachedSummaries);
762 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M,
763 ProgramStateRef State);
765 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) {
766 assert(!M.isInstanceMessage());
767 const ObjCInterfaceDecl *Class = M.getReceiverInterface();
769 return getMethodSummary(M.getSelector(), Class, M.getDecl(),
770 M.getResultType(), ObjCClassMethodSummaries);
773 /// getMethodSummary - This version of getMethodSummary is used to query
774 /// the summary for the current method being analyzed.
775 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) {
776 const ObjCInterfaceDecl *ID = MD->getClassInterface();
777 Selector S = MD->getSelector();
778 QualType ResultTy = MD->getReturnType();
780 ObjCMethodSummariesTy *CachedSummaries;
781 if (MD->isInstanceMethod())
782 CachedSummaries = &ObjCMethodSummaries;
784 CachedSummaries = &ObjCClassMethodSummaries;
786 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries);
789 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD,
790 Selector S, QualType RetTy);
792 /// Determine if there is a special return effect for this function or method.
793 Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy,
796 void updateSummaryFromAnnotations(const RetainSummary *&Summ,
797 const ObjCMethodDecl *MD);
799 void updateSummaryFromAnnotations(const RetainSummary *&Summ,
800 const FunctionDecl *FD);
802 void updateSummaryForCall(const RetainSummary *&Summ,
803 const CallEvent &Call);
805 bool isGCEnabled() const { return GCEnabled; }
807 bool isARCEnabled() const { return ARCEnabled; }
809 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; }
811 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; }
813 friend class RetainSummaryTemplate;
816 // Used to avoid allocating long-term (BPAlloc'd) memory for default retain
817 // summaries. If a function or method looks like it has a default summary, but
818 // it has annotations, the annotations are added to the stack-based template
819 // and then copied into managed memory.
820 class RetainSummaryTemplate {
821 RetainSummaryManager &Manager;
822 const RetainSummary *&RealSummary;
823 RetainSummary ScratchSummary;
826 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr)
827 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {}
829 ~RetainSummaryTemplate() {
831 RealSummary = Manager.getPersistentSummary(ScratchSummary);
834 RetainSummary &operator*() {
836 return ScratchSummary;
839 RetainSummary *operator->() {
841 return &ScratchSummary;
845 } // end anonymous namespace
847 //===----------------------------------------------------------------------===//
848 // Implementation of checker data structures.
849 //===----------------------------------------------------------------------===//
851 ArgEffects RetainSummaryManager::getArgEffects() {
852 ArgEffects AE = ScratchArgs;
853 ScratchArgs = AF.getEmptyMap();
857 const RetainSummary *
858 RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) {
859 // Unique "simple" summaries -- those without ArgEffects.
860 if (OldSumm.isSimple()) {
861 llvm::FoldingSetNodeID ID;
865 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos);
868 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>();
869 new (N) CachedSummaryNode(OldSumm);
870 SimpleSummaries.InsertNode(N, Pos);
873 return &N->getValue();
876 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>();
877 new (Summ) RetainSummary(OldSumm);
881 //===----------------------------------------------------------------------===//
882 // Summary creation for functions (largely uses of Core Foundation).
883 //===----------------------------------------------------------------------===//
885 static bool isRetain(const FunctionDecl *FD, StringRef FName) {
886 return FName.endswith("Retain");
889 static bool isRelease(const FunctionDecl *FD, StringRef FName) {
890 return FName.endswith("Release");
893 static bool isAutorelease(const FunctionDecl *FD, StringRef FName) {
894 return FName.endswith("Autorelease");
897 static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) {
898 // FIXME: Remove FunctionDecl parameter.
899 // FIXME: Is it really okay if MakeCollectable isn't a suffix?
900 return FName.find("MakeCollectable") != StringRef::npos;
903 static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) {
907 case DecRefBridgedTransferred:
910 case MakeCollectable:
911 case UnretainedOutParameter:
912 case RetainedOutParameter:
915 case StopTrackingHard:
916 return StopTrackingHard;
918 case DecRefAndStopTrackingHard:
919 return DecRefAndStopTrackingHard;
921 case DecRefMsgAndStopTrackingHard:
922 return DecRefMsgAndStopTrackingHard;
927 llvm_unreachable("Unknown ArgEffect kind");
930 void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S,
931 const CallEvent &Call) {
932 if (Call.hasNonZeroCallbackArg()) {
933 ArgEffect RecEffect =
934 getStopTrackingHardEquivalent(S->getReceiverEffect());
935 ArgEffect DefEffect =
936 getStopTrackingHardEquivalent(S->getDefaultArgEffect());
938 ArgEffects CustomArgEffects = S->getArgEffects();
939 for (ArgEffects::iterator I = CustomArgEffects.begin(),
940 E = CustomArgEffects.end();
942 ArgEffect Translated = getStopTrackingHardEquivalent(I->second);
943 if (Translated != DefEffect)
944 ScratchArgs = AF.add(ScratchArgs, I->first, Translated);
947 RetEffect RE = RetEffect::MakeNoRetHard();
949 // Special cases where the callback argument CANNOT free the return value.
950 // This can generally only happen if we know that the callback will only be
951 // called when the return value is already being deallocated.
952 if (const SimpleFunctionCall *FC = dyn_cast<SimpleFunctionCall>(&Call)) {
953 if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) {
954 // When the CGBitmapContext is deallocated, the callback here will free
955 // the associated data buffer.
956 // The callback in dispatch_data_create frees the buffer, but not
958 if (Name->isStr("CGBitmapContextCreateWithData") ||
959 Name->isStr("dispatch_data_create"))
960 RE = S->getRetEffect();
964 S = getPersistentSummary(RE, RecEffect, DefEffect);
967 // Special case '[super init];' and '[self init];'
969 // Even though calling '[super init]' without assigning the result to self
970 // and checking if the parent returns 'nil' is a bad pattern, it is common.
971 // Additionally, our Self Init checker already warns about it. To avoid
972 // overwhelming the user with messages from both checkers, we model the case
973 // of '[super init]' in cases when it is not consumed by another expression
974 // as if the call preserves the value of 'self'; essentially, assuming it can
975 // never fail and return 'nil'.
976 // Note, we don't want to just stop tracking the value since we want the
977 // RetainCount checker to report leaks and use-after-free if SelfInit checker
979 if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) {
980 if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) {
982 // Check if the message is not consumed, we know it will not be used in
983 // an assignment, ex: "self = [super init]".
984 const Expr *ME = MC->getOriginExpr();
985 const LocationContext *LCtx = MC->getLocationContext();
986 ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap();
987 if (!PM.isConsumedExpr(ME)) {
988 RetainSummaryTemplate ModifiableSummaryTemplate(S, *this);
989 ModifiableSummaryTemplate->setReceiverEffect(DoNothing);
990 ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet());
996 const RetainSummary *
997 RetainSummaryManager::getSummary(const CallEvent &Call,
998 ProgramStateRef State) {
999 const RetainSummary *Summ;
1000 switch (Call.getKind()) {
1002 Summ = getFunctionSummary(cast<SimpleFunctionCall>(Call).getDecl());
1005 case CE_CXXMemberOperator:
1007 case CE_CXXConstructor:
1008 case CE_CXXDestructor:
1009 case CE_CXXAllocator:
1010 // FIXME: These calls are currently unsupported.
1011 return getPersistentStopSummary();
1012 case CE_ObjCMessage: {
1013 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call);
1014 if (Msg.isInstanceMessage())
1015 Summ = getInstanceMethodSummary(Msg, State);
1017 Summ = getClassMethodSummary(Msg);
1022 updateSummaryForCall(Summ, Call);
1024 assert(Summ && "Unknown call type?");
1028 const RetainSummary *
1029 RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
1030 // If we don't know what function we're calling, use our default summary.
1032 return getDefaultSummary();
1034 // Look up a summary in our cache of FunctionDecls -> Summaries.
1035 FuncSummariesTy::iterator I = FuncSummaries.find(FD);
1036 if (I != FuncSummaries.end())
1039 // No summary? Generate one.
1040 const RetainSummary *S = nullptr;
1041 bool AllowAnnotations = true;
1044 // We generate "stop" summaries for implicitly defined functions.
1045 if (FD->isImplicit()) {
1046 S = getPersistentStopSummary();
1050 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the
1052 const FunctionType* FT = FD->getType()->getAs<FunctionType>();
1053 const IdentifierInfo *II = FD->getIdentifier();
1057 StringRef FName = II->getName();
1059 // Strip away preceding '_'. Doing this here will effect all the checks
1061 FName = FName.substr(FName.find_first_not_of('_'));
1063 // Inspect the result type.
1064 QualType RetTy = FT->getReturnType();
1066 // FIXME: This should all be refactored into a chain of "summary lookup"
1068 assert(ScratchArgs.isEmpty());
1070 if (FName == "pthread_create" || FName == "pthread_setspecific") {
1071 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>.
1072 // This will be addressed better with IPA.
1073 S = getPersistentStopSummary();
1074 } else if (FName == "NSMakeCollectable") {
1075 // Handle: id NSMakeCollectable(CFTypeRef)
1076 S = (RetTy->isObjCIdType())
1077 ? getUnarySummary(FT, cfmakecollectable)
1078 : getPersistentStopSummary();
1079 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained,
1080 // but we can fully model NSMakeCollectable ourselves.
1081 AllowAnnotations = false;
1082 } else if (FName == "CFPlugInInstanceCreate") {
1083 S = getPersistentSummary(RetEffect::MakeNoRet());
1084 } else if (FName == "IOBSDNameMatching" ||
1085 FName == "IOServiceMatching" ||
1086 FName == "IOServiceNameMatching" ||
1087 FName == "IORegistryEntrySearchCFProperty" ||
1088 FName == "IORegistryEntryIDMatching" ||
1089 FName == "IOOpenFirmwarePathMatching") {
1090 // Part of <rdar://problem/6961230>. (IOKit)
1091 // This should be addressed using a API table.
1092 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
1093 DoNothing, DoNothing);
1094 } else if (FName == "IOServiceGetMatchingService" ||
1095 FName == "IOServiceGetMatchingServices") {
1096 // FIXES: <rdar://problem/6326900>
1097 // This should be addressed using a API table. This strcmp is also
1098 // a little gross, but there is no need to super optimize here.
1099 ScratchArgs = AF.add(ScratchArgs, 1, DecRef);
1100 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1101 } else if (FName == "IOServiceAddNotification" ||
1102 FName == "IOServiceAddMatchingNotification") {
1103 // Part of <rdar://problem/6961230>. (IOKit)
1104 // This should be addressed using a API table.
1105 ScratchArgs = AF.add(ScratchArgs, 2, DecRef);
1106 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1107 } else if (FName == "CVPixelBufferCreateWithBytes") {
1108 // FIXES: <rdar://problem/7283567>
1109 // Eventually this can be improved by recognizing that the pixel
1110 // buffer passed to CVPixelBufferCreateWithBytes is released via
1111 // a callback and doing full IPA to make sure this is done correctly.
1112 // FIXME: This function has an out parameter that returns an
1113 // allocated object.
1114 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking);
1115 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1116 } else if (FName == "CGBitmapContextCreateWithData") {
1117 // FIXES: <rdar://problem/7358899>
1118 // Eventually this can be improved by recognizing that 'releaseInfo'
1119 // passed to CGBitmapContextCreateWithData is released via
1120 // a callback and doing full IPA to make sure this is done correctly.
1121 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking);
1122 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
1123 DoNothing, DoNothing);
1124 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") {
1125 // FIXES: <rdar://problem/7283567>
1126 // Eventually this can be improved by recognizing that the pixel
1127 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released
1128 // via a callback and doing full IPA to make sure this is done
1130 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking);
1131 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1132 } else if (FName == "VTCompressionSessionEncodeFrame") {
1133 // The context argument passed to VTCompressionSessionEncodeFrame()
1134 // is passed to the callback specified when creating the session
1135 // (e.g. with VTCompressionSessionCreate()) which can release it.
1136 // To account for this possibility, conservatively stop tracking
1138 ScratchArgs = AF.add(ScratchArgs, 5, StopTracking);
1139 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1140 } else if (FName == "dispatch_set_context" ||
1141 FName == "xpc_connection_set_context") {
1142 // <rdar://problem/11059275> - The analyzer currently doesn't have
1143 // a good way to reason about the finalizer function for libdispatch.
1144 // If we pass a context object that is memory managed, stop tracking it.
1145 // <rdar://problem/13783514> - Same problem, but for XPC.
1146 // FIXME: this hack should possibly go away once we can handle
1147 // libdispatch and XPC finalizers.
1148 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
1149 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1150 } else if (FName.startswith("NSLog")) {
1151 S = getDoNothingSummary();
1152 } else if (FName.startswith("NS") &&
1153 (FName.find("Insert") != StringRef::npos)) {
1154 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
1155 // be deallocated by NSMapRemove. (radar://11152419)
1156 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
1157 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking);
1158 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1161 // Did we get a summary?
1165 if (RetTy->isPointerType()) {
1166 // For CoreFoundation ('CF') types.
1167 if (cocoa::isRefType(RetTy, "CF", FName)) {
1168 if (isRetain(FD, FName)) {
1169 S = getUnarySummary(FT, cfretain);
1170 } else if (isAutorelease(FD, FName)) {
1171 S = getUnarySummary(FT, cfautorelease);
1172 // The headers use cf_consumed, but we can fully model CFAutorelease
1174 AllowAnnotations = false;
1175 } else if (isMakeCollectable(FD, FName)) {
1176 S = getUnarySummary(FT, cfmakecollectable);
1177 AllowAnnotations = false;
1179 S = getCFCreateGetRuleSummary(FD);
1185 // For CoreGraphics ('CG') and CoreVideo ('CV') types.
1186 if (cocoa::isRefType(RetTy, "CG", FName) ||
1187 cocoa::isRefType(RetTy, "CV", FName)) {
1188 if (isRetain(FD, FName))
1189 S = getUnarySummary(FT, cfretain);
1191 S = getCFCreateGetRuleSummary(FD);
1196 // For the Disk Arbitration API (DiskArbitration/DADisk.h)
1197 if (cocoa::isRefType(RetTy, "DADisk") ||
1198 cocoa::isRefType(RetTy, "DADissenter") ||
1199 cocoa::isRefType(RetTy, "DASessionRef")) {
1200 S = getCFCreateGetRuleSummary(FD);
1204 if (FD->hasAttr<CFAuditedTransferAttr>()) {
1205 S = getCFCreateGetRuleSummary(FD);
1212 // Check for release functions, the only kind of functions that we care
1213 // about that don't return a pointer type.
1214 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) {
1216 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2);
1218 if (isRelease(FD, FName))
1219 S = getUnarySummary(FT, cfrelease);
1221 assert (ScratchArgs.isEmpty());
1222 // Remaining CoreFoundation and CoreGraphics functions.
1223 // We use to assume that they all strictly followed the ownership idiom
1224 // and that ownership cannot be transferred. While this is technically
1225 // correct, many methods allow a tracked object to escape. For example:
1227 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...);
1228 // CFDictionaryAddValue(y, key, x);
1230 // ... it is okay to use 'x' since 'y' has a reference to it
1232 // We handle this and similar cases with the follow heuristic. If the
1233 // function name contains "InsertValue", "SetValue", "AddValue",
1234 // "AppendValue", or "SetAttribute", then we assume that arguments may
1235 // "escape." This means that something else holds on to the object,
1236 // allowing it be used even after its local retain count drops to 0.
1237 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos||
1238 StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
1239 StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
1240 StrInStrNoCase(FName, "AppendValue") != StringRef::npos||
1241 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos)
1242 ? MayEscape : DoNothing;
1244 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E);
1250 // If we got all the way here without any luck, use a default summary.
1252 S = getDefaultSummary();
1254 // Annotations override defaults.
1255 if (AllowAnnotations)
1256 updateSummaryFromAnnotations(S, FD);
1258 FuncSummaries[FD] = S;
1262 const RetainSummary *
1263 RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) {
1264 if (coreFoundation::followsCreateRule(FD))
1265 return getCFSummaryCreateRule(FD);
1267 return getCFSummaryGetRule(FD);
1270 const RetainSummary *
1271 RetainSummaryManager::getUnarySummary(const FunctionType* FT,
1272 UnaryFuncKind func) {
1274 // Sanity check that this is *really* a unary function. This can
1275 // happen if people do weird things.
1276 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT);
1277 if (!FTP || FTP->getNumParams() != 1)
1278 return getPersistentStopSummary();
1280 assert (ScratchArgs.isEmpty());
1284 case cfretain: Effect = IncRef; break;
1285 case cfrelease: Effect = DecRef; break;
1286 case cfautorelease: Effect = Autorelease; break;
1287 case cfmakecollectable: Effect = MakeCollectable; break;
1290 ScratchArgs = AF.add(ScratchArgs, 0, Effect);
1291 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
1294 const RetainSummary *
1295 RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) {
1296 assert (ScratchArgs.isEmpty());
1298 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF));
1301 const RetainSummary *
1302 RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) {
1303 assert (ScratchArgs.isEmpty());
1304 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF),
1305 DoNothing, DoNothing);
1308 //===----------------------------------------------------------------------===//
1309 // Summary creation for Selectors.
1310 //===----------------------------------------------------------------------===//
1313 RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy,
1315 if (cocoa::isCocoaObjectRef(RetTy)) {
1316 if (D->hasAttr<NSReturnsRetainedAttr>())
1317 return ObjCAllocRetE;
1319 if (D->hasAttr<NSReturnsNotRetainedAttr>() ||
1320 D->hasAttr<NSReturnsAutoreleasedAttr>())
1321 return RetEffect::MakeNotOwned(RetEffect::ObjC);
1323 } else if (!RetTy->isPointerType()) {
1327 if (D->hasAttr<CFReturnsRetainedAttr>())
1328 return RetEffect::MakeOwned(RetEffect::CF);
1330 if (D->hasAttr<CFReturnsNotRetainedAttr>())
1331 return RetEffect::MakeNotOwned(RetEffect::CF);
1337 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
1338 const FunctionDecl *FD) {
1342 assert(Summ && "Must have a summary to add annotations to.");
1343 RetainSummaryTemplate Template(Summ, *this);
1345 // Effects on the parameters.
1346 unsigned parm_idx = 0;
1347 for (FunctionDecl::param_const_iterator pi = FD->param_begin(),
1348 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) {
1349 const ParmVarDecl *pd = *pi;
1350 if (pd->hasAttr<NSConsumedAttr>())
1351 Template->addArg(AF, parm_idx, DecRefMsg);
1352 else if (pd->hasAttr<CFConsumedAttr>())
1353 Template->addArg(AF, parm_idx, DecRef);
1354 else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
1355 QualType PointeeTy = pd->getType()->getPointeeType();
1356 if (!PointeeTy.isNull())
1357 if (coreFoundation::isCFObjectRef(PointeeTy))
1358 Template->addArg(AF, parm_idx, RetainedOutParameter);
1359 } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
1360 QualType PointeeTy = pd->getType()->getPointeeType();
1361 if (!PointeeTy.isNull())
1362 if (coreFoundation::isCFObjectRef(PointeeTy))
1363 Template->addArg(AF, parm_idx, UnretainedOutParameter);
1367 QualType RetTy = FD->getReturnType();
1368 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD))
1369 Template->setRetEffect(*RetE);
1373 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ,
1374 const ObjCMethodDecl *MD) {
1378 assert(Summ && "Must have a valid summary to add annotations to");
1379 RetainSummaryTemplate Template(Summ, *this);
1381 // Effects on the receiver.
1382 if (MD->hasAttr<NSConsumesSelfAttr>())
1383 Template->setReceiverEffect(DecRefMsg);
1385 // Effects on the parameters.
1386 unsigned parm_idx = 0;
1387 for (ObjCMethodDecl::param_const_iterator
1388 pi=MD->param_begin(), pe=MD->param_end();
1389 pi != pe; ++pi, ++parm_idx) {
1390 const ParmVarDecl *pd = *pi;
1391 if (pd->hasAttr<NSConsumedAttr>())
1392 Template->addArg(AF, parm_idx, DecRefMsg);
1393 else if (pd->hasAttr<CFConsumedAttr>()) {
1394 Template->addArg(AF, parm_idx, DecRef);
1395 } else if (pd->hasAttr<CFReturnsRetainedAttr>()) {
1396 QualType PointeeTy = pd->getType()->getPointeeType();
1397 if (!PointeeTy.isNull())
1398 if (coreFoundation::isCFObjectRef(PointeeTy))
1399 Template->addArg(AF, parm_idx, RetainedOutParameter);
1400 } else if (pd->hasAttr<CFReturnsNotRetainedAttr>()) {
1401 QualType PointeeTy = pd->getType()->getPointeeType();
1402 if (!PointeeTy.isNull())
1403 if (coreFoundation::isCFObjectRef(PointeeTy))
1404 Template->addArg(AF, parm_idx, UnretainedOutParameter);
1408 QualType RetTy = MD->getReturnType();
1409 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD))
1410 Template->setRetEffect(*RetE);
1413 const RetainSummary *
1414 RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD,
1415 Selector S, QualType RetTy) {
1416 // Any special effects?
1417 ArgEffect ReceiverEff = DoNothing;
1418 RetEffect ResultEff = RetEffect::MakeNoRet();
1420 // Check the method family, and apply any default annotations.
1421 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) {
1423 case OMF_initialize:
1424 case OMF_performSelector:
1425 // Assume all Objective-C methods follow Cocoa Memory Management rules.
1426 // FIXME: Does the non-threaded performSelector family really belong here?
1427 // The selector could be, say, @selector(copy).
1428 if (cocoa::isCocoaObjectRef(RetTy))
1429 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC);
1430 else if (coreFoundation::isCFObjectRef(RetTy)) {
1431 // ObjCMethodDecl currently doesn't consider CF objects as valid return
1432 // values for alloc, new, copy, or mutableCopy, so we have to
1433 // double-check with the selector. This is ugly, but there aren't that
1434 // many Objective-C methods that return CF objects, right?
1436 switch (S.getMethodFamily()) {
1440 case OMF_mutableCopy:
1441 ResultEff = RetEffect::MakeOwned(RetEffect::CF);
1444 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
1448 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF);
1453 ResultEff = ObjCInitRetE;
1454 ReceiverEff = DecRefMsg;
1459 case OMF_mutableCopy:
1460 if (cocoa::isCocoaObjectRef(RetTy))
1461 ResultEff = ObjCAllocRetE;
1462 else if (coreFoundation::isCFObjectRef(RetTy))
1463 ResultEff = RetEffect::MakeOwned(RetEffect::CF);
1465 case OMF_autorelease:
1466 ReceiverEff = Autorelease;
1469 ReceiverEff = IncRefMsg;
1472 ReceiverEff = DecRefMsg;
1475 ReceiverEff = Dealloc;
1478 // -self is handled specially by the ExprEngine to propagate the receiver.
1480 case OMF_retainCount:
1482 // These methods don't return objects.
1486 // If one of the arguments in the selector has the keyword 'delegate' we
1487 // should stop tracking the reference count for the receiver. This is
1488 // because the reference count is quite possibly handled by a delegate
1490 if (S.isKeywordSelector()) {
1491 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) {
1492 StringRef Slot = S.getNameForSlot(i);
1493 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) {
1494 if (ResultEff == ObjCInitRetE)
1495 ResultEff = RetEffect::MakeNoRetHard();
1497 ReceiverEff = StopTrackingHard;
1502 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing &&
1503 ResultEff.getKind() == RetEffect::NoRet)
1504 return getDefaultSummary();
1506 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape);
1509 const RetainSummary *
1510 RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg,
1511 ProgramStateRef State) {
1512 const ObjCInterfaceDecl *ReceiverClass = nullptr;
1514 // We do better tracking of the type of the object than the core ExprEngine.
1515 // See if we have its type in our private state.
1516 // FIXME: Eventually replace the use of state->get<RefBindings> with
1517 // a generic API for reasoning about the Objective-C types of symbolic
1519 SVal ReceiverV = Msg.getReceiverSVal();
1520 if (SymbolRef Sym = ReceiverV.getAsLocSymbol())
1521 if (const RefVal *T = getRefBinding(State, Sym))
1522 if (const ObjCObjectPointerType *PT =
1523 T->getType()->getAs<ObjCObjectPointerType>())
1524 ReceiverClass = PT->getInterfaceDecl();
1526 // If we don't know what kind of object this is, fall back to its static type.
1528 ReceiverClass = Msg.getReceiverInterface();
1530 // FIXME: The receiver could be a reference to a class, meaning that
1531 // we should use the class method.
1532 // id x = [NSObject class];
1533 // [x performSelector:... withObject:... afterDelay:...];
1534 Selector S = Msg.getSelector();
1535 const ObjCMethodDecl *Method = Msg.getDecl();
1536 if (!Method && ReceiverClass)
1537 Method = ReceiverClass->getInstanceMethod(S);
1539 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(),
1540 ObjCMethodSummaries);
1543 const RetainSummary *
1544 RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID,
1545 const ObjCMethodDecl *MD, QualType RetTy,
1546 ObjCMethodSummariesTy &CachedSummaries) {
1548 // Look up a summary in our summary cache.
1549 const RetainSummary *Summ = CachedSummaries.find(ID, S);
1552 Summ = getStandardMethodSummary(MD, S, RetTy);
1554 // Annotations override defaults.
1555 updateSummaryFromAnnotations(Summ, MD);
1557 // Memoize the summary.
1558 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ;
1564 void RetainSummaryManager::InitializeClassMethodSummaries() {
1565 assert(ScratchArgs.isEmpty());
1566 // Create the [NSAssertionHandler currentHander] summary.
1567 addClassMethSummary("NSAssertionHandler", "currentHandler",
1568 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC)));
1570 // Create the [NSAutoreleasePool addObject:] summary.
1571 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease);
1572 addClassMethSummary("NSAutoreleasePool", "addObject",
1573 getPersistentSummary(RetEffect::MakeNoRet(),
1574 DoNothing, Autorelease));
1577 void RetainSummaryManager::InitializeMethodSummaries() {
1579 assert (ScratchArgs.isEmpty());
1581 // Create the "init" selector. It just acts as a pass-through for the
1583 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg);
1584 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm);
1586 // awakeAfterUsingCoder: behaves basically like an 'init' method. It
1587 // claims the receiver and returns a retained object.
1588 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx),
1591 // The next methods are allocators.
1592 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE);
1593 const RetainSummary *CFAllocSumm =
1594 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF));
1596 // Create the "retain" selector.
1597 RetEffect NoRet = RetEffect::MakeNoRet();
1598 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg);
1599 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ);
1601 // Create the "release" selector.
1602 Summ = getPersistentSummary(NoRet, DecRefMsg);
1603 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ);
1605 // Create the -dealloc summary.
1606 Summ = getPersistentSummary(NoRet, Dealloc);
1607 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ);
1609 // Create the "autorelease" selector.
1610 Summ = getPersistentSummary(NoRet, Autorelease);
1611 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ);
1613 // For NSWindow, allocated objects are (initially) self-owned.
1614 // FIXME: For now we opt for false negatives with NSWindow, as these objects
1615 // self-own themselves. However, they only do this once they are displayed.
1616 // Thus, we need to track an NSWindow's display status.
1617 // This is tracked in <rdar://problem/6062711>.
1618 // See also http://llvm.org/bugs/show_bug.cgi?id=3714.
1619 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(),
1623 addClassMethSummary("NSWindow", "alloc", NoTrackYet);
1625 // For NSPanel (which subclasses NSWindow), allocated objects are not
1627 // FIXME: For now we don't track NSPanels. object for the same reason
1628 // as for NSWindow objects.
1629 addClassMethSummary("NSPanel", "alloc", NoTrackYet);
1631 // For NSNull, objects returned by +null are singletons that ignore
1632 // retain/release semantics. Just don't track them.
1633 // <rdar://problem/12858915>
1634 addClassMethSummary("NSNull", "null", NoTrackYet);
1636 // Don't track allocated autorelease pools, as it is okay to prematurely
1638 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet);
1639 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false);
1640 addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet);
1642 // Create summaries QCRenderer/QCView -createSnapShotImageOfType:
1643 addInstMethSummary("QCRenderer", AllocSumm,
1644 "createSnapshotImageOfType", nullptr);
1645 addInstMethSummary("QCView", AllocSumm,
1646 "createSnapshotImageOfType", nullptr);
1648 // Create summaries for CIContext, 'createCGImage' and
1649 // 'createCGLayerWithSize'. These objects are CF objects, and are not
1650 // automatically garbage collected.
1651 addInstMethSummary("CIContext", CFAllocSumm,
1652 "createCGImage", "fromRect", nullptr);
1653 addInstMethSummary("CIContext", CFAllocSumm, "createCGImage", "fromRect",
1654 "format", "colorSpace", nullptr);
1655 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", "info",
1659 //===----------------------------------------------------------------------===//
1661 //===----------------------------------------------------------------------===//
1663 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *>
1666 //===-------------===//
1667 // Bug Descriptions. //
1668 //===-------------===//
1670 class CFRefBug : public BugType {
1672 CFRefBug(const CheckerBase *checker, StringRef name)
1673 : BugType(checker, name, categories::MemoryCoreFoundationObjectiveC) {}
1677 // FIXME: Eventually remove.
1678 virtual const char *getDescription() const = 0;
1680 virtual bool isLeak() const { return false; }
1683 class UseAfterRelease : public CFRefBug {
1685 UseAfterRelease(const CheckerBase *checker)
1686 : CFRefBug(checker, "Use-after-release") {}
1688 const char *getDescription() const override {
1689 return "Reference-counted object is used after it is released";
1693 class BadRelease : public CFRefBug {
1695 BadRelease(const CheckerBase *checker) : CFRefBug(checker, "Bad release") {}
1697 const char *getDescription() const override {
1698 return "Incorrect decrement of the reference count of an object that is "
1699 "not owned at this point by the caller";
1703 class DeallocGC : public CFRefBug {
1705 DeallocGC(const CheckerBase *checker)
1706 : CFRefBug(checker, "-dealloc called while using garbage collection") {}
1708 const char *getDescription() const override {
1709 return "-dealloc called while using garbage collection";
1713 class DeallocNotOwned : public CFRefBug {
1715 DeallocNotOwned(const CheckerBase *checker)
1716 : CFRefBug(checker, "-dealloc sent to non-exclusively owned object") {}
1718 const char *getDescription() const override {
1719 return "-dealloc sent to object that may be referenced elsewhere";
1723 class OverAutorelease : public CFRefBug {
1725 OverAutorelease(const CheckerBase *checker)
1726 : CFRefBug(checker, "Object autoreleased too many times") {}
1728 const char *getDescription() const override {
1729 return "Object autoreleased too many times";
1733 class ReturnedNotOwnedForOwned : public CFRefBug {
1735 ReturnedNotOwnedForOwned(const CheckerBase *checker)
1736 : CFRefBug(checker, "Method should return an owned object") {}
1738 const char *getDescription() const override {
1739 return "Object with a +0 retain count returned to caller where a +1 "
1740 "(owning) retain count is expected";
1744 class Leak : public CFRefBug {
1746 Leak(const CheckerBase *checker, StringRef name) : CFRefBug(checker, name) {
1747 // Leaks should not be reported if they are post-dominated by a sink.
1748 setSuppressOnSink(true);
1751 const char *getDescription() const override { return ""; }
1753 bool isLeak() const override { return true; }
1760 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> {
1763 const SummaryLogTy &SummaryLog;
1767 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log)
1768 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {}
1770 void Profile(llvm::FoldingSetNodeID &ID) const override {
1776 std::shared_ptr<PathDiagnosticPiece> VisitNode(const ExplodedNode *N,
1777 const ExplodedNode *PrevN,
1778 BugReporterContext &BRC,
1779 BugReport &BR) override;
1781 std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
1782 const ExplodedNode *N,
1783 BugReport &BR) override;
1786 class CFRefLeakReportVisitor : public CFRefReportVisitor {
1788 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled,
1789 const SummaryLogTy &log)
1790 : CFRefReportVisitor(sym, GCEnabled, log) {}
1792 std::unique_ptr<PathDiagnosticPiece> getEndPath(BugReporterContext &BRC,
1793 const ExplodedNode *N,
1794 BugReport &BR) override;
1796 std::unique_ptr<BugReporterVisitor> clone() const override {
1797 // The curiously-recurring template pattern only works for one level of
1798 // subclassing. Rather than make a new template base for
1799 // CFRefReportVisitor, we simply override clone() to do the right thing.
1800 // This could be trouble someday if BugReporterVisitorImpl is ever
1801 // used for something else besides a convenient implementation of clone().
1802 return llvm::make_unique<CFRefLeakReportVisitor>(*this);
1806 class CFRefReport : public BugReport {
1807 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled);
1810 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1811 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1812 bool registerVisitor = true)
1813 : BugReport(D, D.getDescription(), n) {
1814 if (registerVisitor)
1815 addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
1816 addGCModeDescription(LOpts, GCEnabled);
1819 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1820 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1822 : BugReport(D, D.getDescription(), endText, n) {
1823 addVisitor(llvm::make_unique<CFRefReportVisitor>(sym, GCEnabled, Log));
1824 addGCModeDescription(LOpts, GCEnabled);
1827 llvm::iterator_range<ranges_iterator> getRanges() override {
1828 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType());
1829 if (!BugTy.isLeak())
1830 return BugReport::getRanges();
1831 return llvm::make_range(ranges_iterator(), ranges_iterator());
1835 class CFRefLeakReport : public CFRefReport {
1836 const MemRegion* AllocBinding;
1838 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled,
1839 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym,
1840 CheckerContext &Ctx,
1841 bool IncludeAllocationLine);
1843 PathDiagnosticLocation getLocation(const SourceManager &SM) const override {
1844 assert(Location.isValid());
1848 } // end anonymous namespace
1850 void CFRefReport::addGCModeDescription(const LangOptions &LOpts,
1852 const char *GCModeDescription = nullptr;
1854 switch (LOpts.getGC()) {
1855 case LangOptions::GCOnly:
1857 GCModeDescription = "Code is compiled to only use garbage collection";
1860 case LangOptions::NonGC:
1862 GCModeDescription = "Code is compiled to use reference counts";
1865 case LangOptions::HybridGC:
1867 GCModeDescription = "Code is compiled to use either garbage collection "
1868 "(GC) or reference counts (non-GC). The bug occurs "
1872 GCModeDescription = "Code is compiled to use either garbage collection "
1873 "(GC) or reference counts (non-GC). The bug occurs "
1879 assert(GCModeDescription && "invalid/unknown GC mode");
1880 addExtraText(GCModeDescription);
1883 static bool isNumericLiteralExpression(const Expr *E) {
1884 // FIXME: This set of cases was copied from SemaExprObjC.
1885 return isa<IntegerLiteral>(E) ||
1886 isa<CharacterLiteral>(E) ||
1887 isa<FloatingLiteral>(E) ||
1888 isa<ObjCBoolLiteralExpr>(E) ||
1889 isa<CXXBoolLiteralExpr>(E);
1892 /// Returns true if this stack frame is for an Objective-C method that is a
1893 /// property getter or setter whose body has been synthesized by the analyzer.
1894 static bool isSynthesizedAccessor(const StackFrameContext *SFC) {
1895 auto Method = dyn_cast_or_null<ObjCMethodDecl>(SFC->getDecl());
1896 if (!Method || !Method->isPropertyAccessor())
1899 return SFC->getAnalysisDeclContext()->isBodyAutosynthesized();
1902 std::shared_ptr<PathDiagnosticPiece>
1903 CFRefReportVisitor::VisitNode(const ExplodedNode *N, const ExplodedNode *PrevN,
1904 BugReporterContext &BRC, BugReport &BR) {
1905 // FIXME: We will eventually need to handle non-statement-based events
1906 // (__attribute__((cleanup))).
1907 if (!N->getLocation().getAs<StmtPoint>())
1910 // Check if the type state has changed.
1911 ProgramStateRef PrevSt = PrevN->getState();
1912 ProgramStateRef CurrSt = N->getState();
1913 const LocationContext *LCtx = N->getLocationContext();
1915 const RefVal* CurrT = getRefBinding(CurrSt, Sym);
1916 if (!CurrT) return nullptr;
1918 const RefVal &CurrV = *CurrT;
1919 const RefVal *PrevT = getRefBinding(PrevSt, Sym);
1921 // Create a string buffer to constain all the useful things we want
1922 // to tell the user.
1924 llvm::raw_string_ostream os(sbuf);
1926 // This is the allocation site since the previous node had no bindings
1929 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
1931 if (isa<ObjCIvarRefExpr>(S) &&
1932 isSynthesizedAccessor(LCtx->getCurrentStackFrame())) {
1933 S = LCtx->getCurrentStackFrame()->getCallSite();
1936 if (isa<ObjCArrayLiteral>(S)) {
1937 os << "NSArray literal is an object with a +0 retain count";
1939 else if (isa<ObjCDictionaryLiteral>(S)) {
1940 os << "NSDictionary literal is an object with a +0 retain count";
1942 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) {
1943 if (isNumericLiteralExpression(BL->getSubExpr()))
1944 os << "NSNumber literal is an object with a +0 retain count";
1946 const ObjCInterfaceDecl *BoxClass = nullptr;
1947 if (const ObjCMethodDecl *Method = BL->getBoxingMethod())
1948 BoxClass = Method->getClassInterface();
1950 // We should always be able to find the boxing class interface,
1951 // but consider this future-proofing.
1953 os << *BoxClass << " b";
1957 os << "oxed expression produces an object with a +0 retain count";
1960 else if (isa<ObjCIvarRefExpr>(S)) {
1961 os << "Object loaded from instance variable";
1964 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
1965 // Get the name of the callee (if it is available).
1966 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx);
1967 if (const FunctionDecl *FD = X.getAsFunctionDecl())
1968 os << "Call to function '" << *FD << '\'';
1970 os << "function call";
1973 assert(isa<ObjCMessageExpr>(S));
1974 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager();
1975 CallEventRef<ObjCMethodCall> Call
1976 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx);
1978 switch (Call->getMessageKind()) {
1982 case OCM_PropertyAccess:
1991 if (CurrV.getObjKind() == RetEffect::CF) {
1992 if (Sym->getType().isNull()) {
1993 os << " returns a Core Foundation object with a ";
1995 os << " returns a Core Foundation object of type "
1996 << Sym->getType().getAsString() << " with a ";
2000 assert (CurrV.getObjKind() == RetEffect::ObjC);
2001 QualType T = Sym->getType();
2002 if (T.isNull() || !isa<ObjCObjectPointerType>(T)) {
2003 os << " returns an Objective-C object with a ";
2005 const ObjCObjectPointerType *PT = cast<ObjCObjectPointerType>(T);
2006 os << " returns an instance of "
2007 << PT->getPointeeType().getAsString() << " with a ";
2011 if (CurrV.isOwned()) {
2012 os << "+1 retain count";
2015 assert(CurrV.getObjKind() == RetEffect::CF);
2017 "Core Foundation objects are not automatically garbage collected.";
2021 assert (CurrV.isNotOwned());
2022 os << "+0 retain count";
2026 PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
2027 N->getLocationContext());
2028 return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
2031 // Gather up the effects that were performed on the object at this
2033 SmallVector<ArgEffect, 2> AEffects;
2035 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N);
2036 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) {
2037 // We only have summaries attached to nodes after evaluating CallExpr and
2038 // ObjCMessageExprs.
2039 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2041 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
2042 // Iterate through the parameter expressions and see if the symbol
2043 // was ever passed as an argument.
2046 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end();
2047 AI!=AE; ++AI, ++i) {
2049 // Retrieve the value of the argument. Is it the symbol
2050 // we are interested in?
2051 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym)
2054 // We have an argument. Get the effect!
2055 AEffects.push_back(Summ->getArg(i));
2058 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) {
2059 if (const Expr *receiver = ME->getInstanceReceiver())
2060 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx)
2061 .getAsLocSymbol() == Sym) {
2062 // The symbol we are tracking is the receiver.
2063 AEffects.push_back(Summ->getReceiverEffect());
2069 // Get the previous type state.
2070 RefVal PrevV = *PrevT;
2072 // Specially handle -dealloc.
2073 if (!GCEnabled && std::find(AEffects.begin(), AEffects.end(), Dealloc) !=
2075 // Determine if the object's reference count was pushed to zero.
2076 assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
2077 // We may not have transitioned to 'release' if we hit an error.
2078 // This case is handled elsewhere.
2079 if (CurrV.getKind() == RefVal::Released) {
2080 assert(CurrV.getCombinedCounts() == 0);
2081 os << "Object released by directly sending the '-dealloc' message";
2086 // Specially handle CFMakeCollectable and friends.
2087 if (std::find(AEffects.begin(), AEffects.end(), MakeCollectable) !=
2089 // Get the name of the function.
2090 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2092 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx);
2093 const FunctionDecl *FD = X.getAsFunctionDecl();
2096 // Determine if the object's reference count was pushed to zero.
2097 assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
2099 os << "In GC mode a call to '" << *FD
2100 << "' decrements an object's retain count and registers the "
2101 "object with the garbage collector. ";
2103 if (CurrV.getKind() == RefVal::Released) {
2104 assert(CurrV.getCount() == 0);
2105 os << "Since it now has a 0 retain count the object can be "
2106 "automatically collected by the garbage collector.";
2109 os << "An object must have a 0 retain count to be garbage collected. "
2110 "After this call its retain count is +" << CurrV.getCount()
2114 os << "When GC is not enabled a call to '" << *FD
2115 << "' has no effect on its argument.";
2117 // Nothing more to say.
2121 // Determine if the typestate has changed.
2122 if (!PrevV.hasSameState(CurrV))
2123 switch (CurrV.getKind()) {
2125 case RefVal::NotOwned:
2126 if (PrevV.getCount() == CurrV.getCount()) {
2127 // Did an autorelease message get sent?
2128 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount())
2131 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount());
2132 os << "Object autoreleased";
2136 if (PrevV.getCount() > CurrV.getCount())
2137 os << "Reference count decremented.";
2139 os << "Reference count incremented.";
2141 if (unsigned Count = CurrV.getCount())
2142 os << " The object now has a +" << Count << " retain count.";
2144 if (PrevV.getKind() == RefVal::Released) {
2145 assert(GCEnabled && CurrV.getCount() > 0);
2146 os << " The object is not eligible for garbage collection until "
2147 "the retain count reaches 0 again.";
2152 case RefVal::Released:
2153 if (CurrV.getIvarAccessHistory() ==
2154 RefVal::IvarAccessHistory::ReleasedAfterDirectAccess &&
2155 CurrV.getIvarAccessHistory() != PrevV.getIvarAccessHistory()) {
2156 os << "Strong instance variable relinquished. ";
2158 os << "Object released.";
2161 case RefVal::ReturnedOwned:
2162 // Autoreleases can be applied after marking a node ReturnedOwned.
2163 if (CurrV.getAutoreleaseCount())
2166 os << "Object returned to caller as an owning reference (single "
2167 "retain count transferred to caller)";
2170 case RefVal::ReturnedNotOwned:
2171 os << "Object returned to caller with a +0 retain count";
2178 // Emit any remaining diagnostics for the argument effects (if any).
2179 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(),
2180 E=AEffects.end(); I != E; ++I) {
2182 // A bunch of things have alternate behavior under GC.
2187 os << "In GC mode an 'autorelease' has no effect.";
2190 os << "In GC mode the 'retain' message has no effect.";
2193 os << "In GC mode the 'release' message has no effect.";
2199 if (os.str().empty())
2200 return nullptr; // We have nothing to say!
2202 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
2203 PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
2204 N->getLocationContext());
2205 auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
2207 // Add the range by scanning the children of the statement for any bindings
2209 for (const Stmt *Child : S->children())
2210 if (const Expr *Exp = dyn_cast_or_null<Expr>(Child))
2211 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) {
2212 P->addRange(Exp->getSourceRange());
2216 return std::move(P);
2220 // Find the first node in the current function context that referred to the
2221 // tracked symbol and the memory location that value was stored to. Note, the
2222 // value is only reported if the allocation occurred in the same function as
2223 // the leak. The function can also return a location context, which should be
2224 // treated as interesting.
2225 struct AllocationInfo {
2226 const ExplodedNode* N;
2228 const LocationContext *InterestingMethodContext;
2229 AllocationInfo(const ExplodedNode *InN,
2230 const MemRegion *InR,
2231 const LocationContext *InInterestingMethodContext) :
2232 N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {}
2234 } // end anonymous namespace
2236 static AllocationInfo
2237 GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N,
2239 const ExplodedNode *AllocationNode = N;
2240 const ExplodedNode *AllocationNodeInCurrentOrParentContext = N;
2241 const MemRegion *FirstBinding = nullptr;
2242 const LocationContext *LeakContext = N->getLocationContext();
2244 // The location context of the init method called on the leaked object, if
2246 const LocationContext *InitMethodContext = nullptr;
2249 ProgramStateRef St = N->getState();
2250 const LocationContext *NContext = N->getLocationContext();
2252 if (!getRefBinding(St, Sym))
2255 StoreManager::FindUniqueBinding FB(Sym);
2256 StateMgr.iterBindings(St, FB);
2259 const MemRegion *R = FB.getRegion();
2260 const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>();
2261 // Do not show local variables belonging to a function other than
2262 // where the error is reported.
2263 if (!VR || VR->getStackFrame() == LeakContext->getCurrentStackFrame())
2267 // AllocationNode is the last node in which the symbol was tracked.
2270 // AllocationNodeInCurrentContext, is the last node in the current or
2271 // parent context in which the symbol was tracked.
2273 // Note that the allocation site might be in the parent conext. For example,
2274 // the case where an allocation happens in a block that captures a reference
2275 // to it and that reference is overwritten/dropped by another call to
2277 if (NContext == LeakContext || NContext->isParentOf(LeakContext))
2278 AllocationNodeInCurrentOrParentContext = N;
2280 // Find the last init that was called on the given symbol and store the
2281 // init method's location context.
2282 if (!InitMethodContext)
2283 if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) {
2284 const Stmt *CE = CEP->getCallExpr();
2285 if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) {
2286 const Stmt *RecExpr = ME->getInstanceReceiver();
2288 SVal RecV = St->getSVal(RecExpr, NContext);
2289 if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym)
2290 InitMethodContext = CEP->getCalleeContext();
2295 N = N->pred_empty() ? nullptr : *(N->pred_begin());
2298 // If we are reporting a leak of the object that was allocated with alloc,
2299 // mark its init method as interesting.
2300 const LocationContext *InterestingMethodContext = nullptr;
2301 if (InitMethodContext) {
2302 const ProgramPoint AllocPP = AllocationNode->getLocation();
2303 if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>())
2304 if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>())
2305 if (ME->getMethodFamily() == OMF_alloc)
2306 InterestingMethodContext = InitMethodContext;
2309 // If allocation happened in a function different from the leak node context,
2310 // do not report the binding.
2311 assert(N && "Could not find allocation node");
2312 if (N->getLocationContext() != LeakContext) {
2313 FirstBinding = nullptr;
2316 return AllocationInfo(AllocationNodeInCurrentOrParentContext,
2318 InterestingMethodContext);
2321 std::unique_ptr<PathDiagnosticPiece>
2322 CFRefReportVisitor::getEndPath(BugReporterContext &BRC,
2323 const ExplodedNode *EndN, BugReport &BR) {
2324 BR.markInteresting(Sym);
2325 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR);
2328 std::unique_ptr<PathDiagnosticPiece>
2329 CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
2330 const ExplodedNode *EndN, BugReport &BR) {
2332 // Tell the BugReporterContext to report cases when the tracked symbol is
2333 // assigned to different variables, etc.
2334 BR.markInteresting(Sym);
2336 // We are reporting a leak. Walk up the graph to get to the first node where
2337 // the symbol appeared, and also get the first VarDecl that tracked object
2339 AllocationInfo AllocI =
2340 GetAllocationSite(BRC.getStateManager(), EndN, Sym);
2342 const MemRegion* FirstBinding = AllocI.R;
2343 BR.markInteresting(AllocI.InterestingMethodContext);
2345 SourceManager& SM = BRC.getSourceManager();
2347 // Compute an actual location for the leak. Sometimes a leak doesn't
2348 // occur at an actual statement (e.g., transition between blocks; end
2349 // of function) so we need to walk the graph and compute a real location.
2350 const ExplodedNode *LeakN = EndN;
2351 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM);
2354 llvm::raw_string_ostream os(sbuf);
2356 os << "Object leaked: ";
2359 os << "object allocated and stored into '"
2360 << FirstBinding->getString() << '\'';
2363 os << "allocated object";
2365 // Get the retain count.
2366 const RefVal* RV = getRefBinding(EndN->getState(), Sym);
2369 if (RV->getKind() == RefVal::ErrorLeakReturned) {
2370 // FIXME: Per comments in rdar://6320065, "create" only applies to CF
2371 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership
2372 // to the caller for NS objects.
2373 const Decl *D = &EndN->getCodeDecl();
2375 os << (isa<ObjCMethodDecl>(D) ? " is returned from a method "
2376 : " is returned from a function ");
2378 if (D->hasAttr<CFReturnsNotRetainedAttr>())
2379 os << "that is annotated as CF_RETURNS_NOT_RETAINED";
2380 else if (D->hasAttr<NSReturnsNotRetainedAttr>())
2381 os << "that is annotated as NS_RETURNS_NOT_RETAINED";
2383 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
2384 if (BRC.getASTContext().getLangOpts().ObjCAutoRefCount) {
2385 os << "managed by Automatic Reference Counting";
2387 os << "whose name ('" << MD->getSelector().getAsString()
2388 << "') does not start with "
2389 "'copy', 'mutableCopy', 'alloc' or 'new'."
2390 " This violates the naming convention rules"
2391 " given in the Memory Management Guide for Cocoa";
2395 const FunctionDecl *FD = cast<FunctionDecl>(D);
2396 os << "whose name ('" << *FD
2397 << "') does not contain 'Copy' or 'Create'. This violates the naming"
2398 " convention rules given in the Memory Management Guide for Core"
2403 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) {
2404 const ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl());
2405 os << " and returned from method '" << MD.getSelector().getAsString()
2406 << "' is potentially leaked when using garbage collection. Callers "
2407 "of this method do not expect a returned object with a +1 retain "
2408 "count since they expect the object to be managed by the garbage "
2412 os << " is not referenced later in this execution path and has a retain "
2413 "count of +" << RV->getCount();
2415 return llvm::make_unique<PathDiagnosticEventPiece>(L, os.str());
2418 CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts,
2419 bool GCEnabled, const SummaryLogTy &Log,
2420 ExplodedNode *n, SymbolRef sym,
2421 CheckerContext &Ctx,
2422 bool IncludeAllocationLine)
2423 : CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) {
2425 // Most bug reports are cached at the location where they occurred.
2426 // With leaks, we want to unique them by the location where they were
2427 // allocated, and only report a single path. To do this, we need to find
2428 // the allocation site of a piece of tracked memory, which we do via a
2429 // call to GetAllocationSite. This will walk the ExplodedGraph backwards.
2430 // Note that this is *not* the trimmed graph; we are guaranteed, however,
2431 // that all ancestor nodes that represent the allocation site have the
2432 // same SourceLocation.
2433 const ExplodedNode *AllocNode = nullptr;
2435 const SourceManager& SMgr = Ctx.getSourceManager();
2437 AllocationInfo AllocI =
2438 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym);
2440 AllocNode = AllocI.N;
2441 AllocBinding = AllocI.R;
2442 markInteresting(AllocI.InterestingMethodContext);
2444 // Get the SourceLocation for the allocation site.
2445 // FIXME: This will crash the analyzer if an allocation comes from an
2446 // implicit call (ex: a destructor call).
2447 // (Currently there are no such allocations in Cocoa, though.)
2448 const Stmt *AllocStmt = PathDiagnosticLocation::getStmt(AllocNode);
2449 assert(AllocStmt && "Cannot find allocation statement");
2451 PathDiagnosticLocation AllocLocation =
2452 PathDiagnosticLocation::createBegin(AllocStmt, SMgr,
2453 AllocNode->getLocationContext());
2454 Location = AllocLocation;
2456 // Set uniqieing info, which will be used for unique the bug reports. The
2457 // leaks should be uniqued on the allocation site.
2458 UniqueingLocation = AllocLocation;
2459 UniqueingDecl = AllocNode->getLocationContext()->getDecl();
2461 // Fill in the description of the bug.
2462 Description.clear();
2463 llvm::raw_string_ostream os(Description);
2464 os << "Potential leak ";
2466 os << "(when using garbage collection) ";
2467 os << "of an object";
2470 os << " stored into '" << AllocBinding->getString() << '\'';
2471 if (IncludeAllocationLine) {
2472 FullSourceLoc SL(AllocStmt->getLocStart(), Ctx.getSourceManager());
2473 os << " (allocated on line " << SL.getSpellingLineNumber() << ")";
2477 addVisitor(llvm::make_unique<CFRefLeakReportVisitor>(sym, GCEnabled, Log));
2480 //===----------------------------------------------------------------------===//
2481 // Main checker logic.
2482 //===----------------------------------------------------------------------===//
2485 class RetainCountChecker
2486 : public Checker< check::Bind,
2490 check::PostStmt<BlockExpr>,
2491 check::PostStmt<CastExpr>,
2492 check::PostStmt<ObjCArrayLiteral>,
2493 check::PostStmt<ObjCDictionaryLiteral>,
2494 check::PostStmt<ObjCBoxedExpr>,
2495 check::PostStmt<ObjCIvarRefExpr>,
2497 check::PreStmt<ReturnStmt>,
2498 check::RegionChanges,
2501 mutable std::unique_ptr<CFRefBug> useAfterRelease, releaseNotOwned;
2502 mutable std::unique_ptr<CFRefBug> deallocGC, deallocNotOwned;
2503 mutable std::unique_ptr<CFRefBug> overAutorelease, returnNotOwnedForOwned;
2504 mutable std::unique_ptr<CFRefBug> leakWithinFunction, leakAtReturn;
2505 mutable std::unique_ptr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC;
2507 typedef llvm::DenseMap<SymbolRef, const CheckerProgramPointTag *> SymbolTagMap;
2509 // This map is only used to ensure proper deletion of any allocated tags.
2510 mutable SymbolTagMap DeadSymbolTags;
2512 mutable std::unique_ptr<RetainSummaryManager> Summaries;
2513 mutable std::unique_ptr<RetainSummaryManager> SummariesGC;
2514 mutable SummaryLogTy SummaryLog;
2515 mutable bool ShouldResetSummaryLog;
2517 /// Optional setting to indicate if leak reports should include
2518 /// the allocation line.
2519 mutable bool IncludeAllocationLine;
2522 RetainCountChecker(AnalyzerOptions &AO)
2523 : ShouldResetSummaryLog(false),
2524 IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {}
2526 ~RetainCountChecker() override { DeleteContainerSeconds(DeadSymbolTags); }
2528 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR,
2529 ExprEngine &Eng) const {
2530 // FIXME: This is a hack to make sure the summary log gets cleared between
2531 // analyses of different code bodies.
2533 // Why is this necessary? Because a checker's lifetime is tied to a
2534 // translation unit, but an ExplodedGraph's lifetime is just a code body.
2535 // Once in a blue moon, a new ExplodedNode will have the same address as an
2536 // old one with an associated summary, and the bug report visitor gets very
2537 // confused. (To make things worse, the summary lifetime is currently also
2538 // tied to a code body, so we get a crash instead of incorrect results.)
2540 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph
2541 // changes, things will start going wrong again. Really the lifetime of this
2542 // log needs to be tied to either the specific nodes in it or the entire
2543 // ExplodedGraph, not to a specific part of the code being analyzed.
2545 // (Also, having stateful local data means that the same checker can't be
2546 // used from multiple threads, but a lot of checkers have incorrect
2547 // assumptions about that anyway. So that wasn't a priority at the time of
2550 // This happens at the end of analysis, but bug reports are emitted /after/
2551 // this point. So we can't just clear the summary log now. Instead, we mark
2552 // that the next time we access the summary log, it should be cleared.
2554 // If we never reset the summary log during /this/ code body analysis,
2555 // there were no new summaries. There might still have been summaries from
2556 // the /last/ analysis, so clear them out to make sure the bug report
2557 // visitors don't get confused.
2558 if (ShouldResetSummaryLog)
2561 ShouldResetSummaryLog = !SummaryLog.empty();
2564 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts,
2565 bool GCEnabled) const {
2567 if (!leakWithinFunctionGC)
2568 leakWithinFunctionGC.reset(new Leak(this, "Leak of object when using "
2569 "garbage collection"));
2570 return leakWithinFunctionGC.get();
2572 if (!leakWithinFunction) {
2573 if (LOpts.getGC() == LangOptions::HybridGC) {
2574 leakWithinFunction.reset(new Leak(this,
2575 "Leak of object when not using "
2576 "garbage collection (GC) in "
2577 "dual GC/non-GC code"));
2579 leakWithinFunction.reset(new Leak(this, "Leak"));
2582 return leakWithinFunction.get();
2586 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const {
2588 if (!leakAtReturnGC)
2589 leakAtReturnGC.reset(new Leak(this,
2590 "Leak of returned object when using "
2591 "garbage collection"));
2592 return leakAtReturnGC.get();
2594 if (!leakAtReturn) {
2595 if (LOpts.getGC() == LangOptions::HybridGC) {
2596 leakAtReturn.reset(new Leak(this,
2597 "Leak of returned object when not using "
2598 "garbage collection (GC) in dual "
2601 leakAtReturn.reset(new Leak(this, "Leak of returned object"));
2604 return leakAtReturn.get();
2608 RetainSummaryManager &getSummaryManager(ASTContext &Ctx,
2609 bool GCEnabled) const {
2610 // FIXME: We don't support ARC being turned on and off during one analysis.
2611 // (nor, for that matter, do we support changing ASTContexts)
2612 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount;
2615 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled));
2617 assert(SummariesGC->isARCEnabled() == ARCEnabled);
2618 return *SummariesGC;
2621 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled));
2623 assert(Summaries->isARCEnabled() == ARCEnabled);
2628 RetainSummaryManager &getSummaryManager(CheckerContext &C) const {
2629 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled());
2632 void printState(raw_ostream &Out, ProgramStateRef State,
2633 const char *NL, const char *Sep) const override;
2635 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const;
2636 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
2637 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const;
2639 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const;
2640 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const;
2641 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const;
2643 void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const;
2645 void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
2647 void checkSummary(const RetainSummary &Summ, const CallEvent &Call,
2648 CheckerContext &C) const;
2650 void processSummaryOfInlined(const RetainSummary &Summ,
2651 const CallEvent &Call,
2652 CheckerContext &C) const;
2654 bool evalCall(const CallExpr *CE, CheckerContext &C) const;
2656 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
2657 bool Assumption) const;
2660 checkRegionChanges(ProgramStateRef state,
2661 const InvalidatedSymbols *invalidated,
2662 ArrayRef<const MemRegion *> ExplicitRegions,
2663 ArrayRef<const MemRegion *> Regions,
2664 const CallEvent *Call) const;
2666 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
2667 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C,
2668 ExplodedNode *Pred, RetEffect RE, RefVal X,
2669 SymbolRef Sym, ProgramStateRef state) const;
2671 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
2672 void checkEndFunction(CheckerContext &C) const;
2674 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym,
2675 RefVal V, ArgEffect E, RefVal::Kind &hasErr,
2676 CheckerContext &C) const;
2678 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange,
2679 RefVal::Kind ErrorKind, SymbolRef Sym,
2680 CheckerContext &C) const;
2682 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const;
2684 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const;
2686 ProgramStateRef handleSymbolDeath(ProgramStateRef state,
2687 SymbolRef sid, RefVal V,
2688 SmallVectorImpl<SymbolRef> &Leaked) const;
2691 handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred,
2692 const ProgramPointTag *Tag, CheckerContext &Ctx,
2693 SymbolRef Sym, RefVal V) const;
2695 ExplodedNode *processLeaks(ProgramStateRef state,
2696 SmallVectorImpl<SymbolRef> &Leaked,
2697 CheckerContext &Ctx,
2698 ExplodedNode *Pred = nullptr) const;
2700 } // end anonymous namespace
2703 class StopTrackingCallback final : public SymbolVisitor {
2704 ProgramStateRef state;
2706 StopTrackingCallback(ProgramStateRef st) : state(std::move(st)) {}
2707 ProgramStateRef getState() const { return state; }
2709 bool VisitSymbol(SymbolRef sym) override {
2710 state = state->remove<RefBindings>(sym);
2714 } // end anonymous namespace
2716 //===----------------------------------------------------------------------===//
2717 // Handle statements that may have an effect on refcounts.
2718 //===----------------------------------------------------------------------===//
2720 void RetainCountChecker::checkPostStmt(const BlockExpr *BE,
2721 CheckerContext &C) const {
2723 // Scan the BlockDecRefExprs for any object the retain count checker
2725 if (!BE->getBlockDecl()->hasCaptures())
2728 ProgramStateRef state = C.getState();
2729 const BlockDataRegion *R =
2730 cast<BlockDataRegion>(state->getSVal(BE,
2731 C.getLocationContext()).getAsRegion());
2733 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(),
2734 E = R->referenced_vars_end();
2739 // FIXME: For now we invalidate the tracking of all symbols passed to blocks
2740 // via captured variables, even though captured variables result in a copy
2741 // and in implicit increment/decrement of a retain count.
2742 SmallVector<const MemRegion*, 10> Regions;
2743 const LocationContext *LC = C.getLocationContext();
2744 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager();
2746 for ( ; I != E; ++I) {
2747 const VarRegion *VR = I.getCapturedRegion();
2748 if (VR->getSuperRegion() == R) {
2749 VR = MemMgr.getVarRegion(VR->getDecl(), LC);
2751 Regions.push_back(VR);
2755 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(),
2756 Regions.data() + Regions.size()).getState();
2757 C.addTransition(state);
2760 void RetainCountChecker::checkPostStmt(const CastExpr *CE,
2761 CheckerContext &C) const {
2762 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE);
2766 ArgEffect AE = IncRef;
2768 switch (BE->getBridgeKind()) {
2769 case clang::OBC_Bridge:
2772 case clang::OBC_BridgeRetained:
2775 case clang::OBC_BridgeTransfer:
2776 AE = DecRefBridgedTransferred;
2780 ProgramStateRef state = C.getState();
2781 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol();
2784 const RefVal* T = getRefBinding(state, Sym);
2788 RefVal::Kind hasErr = (RefVal::Kind) 0;
2789 state = updateSymbol(state, Sym, *T, AE, hasErr, C);
2792 // FIXME: If we get an error during a bridge cast, should we report it?
2796 C.addTransition(state);
2799 void RetainCountChecker::processObjCLiterals(CheckerContext &C,
2800 const Expr *Ex) const {
2801 ProgramStateRef state = C.getState();
2802 const ExplodedNode *pred = C.getPredecessor();
2803 for (const Stmt *Child : Ex->children()) {
2804 SVal V = state->getSVal(Child, pred->getLocationContext());
2805 if (SymbolRef sym = V.getAsSymbol())
2806 if (const RefVal* T = getRefBinding(state, sym)) {
2807 RefVal::Kind hasErr = (RefVal::Kind) 0;
2808 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C);
2810 processNonLeakError(state, Child->getSourceRange(), hasErr, sym, C);
2816 // Return the object as autoreleased.
2817 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC);
2819 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) {
2820 QualType ResultTy = Ex->getType();
2821 state = setRefBinding(state, sym,
2822 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
2825 C.addTransition(state);
2828 void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL,
2829 CheckerContext &C) const {
2830 // Apply the 'MayEscape' to all values.
2831 processObjCLiterals(C, AL);
2834 void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL,
2835 CheckerContext &C) const {
2836 // Apply the 'MayEscape' to all keys and values.
2837 processObjCLiterals(C, DL);
2840 void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex,
2841 CheckerContext &C) const {
2842 const ExplodedNode *Pred = C.getPredecessor();
2843 const LocationContext *LCtx = Pred->getLocationContext();
2844 ProgramStateRef State = Pred->getState();
2846 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) {
2847 QualType ResultTy = Ex->getType();
2848 State = setRefBinding(State, Sym,
2849 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy));
2852 C.addTransition(State);
2855 void RetainCountChecker::checkPostStmt(const ObjCIvarRefExpr *IRE,
2856 CheckerContext &C) const {
2857 Optional<Loc> IVarLoc = C.getSVal(IRE).getAs<Loc>();
2861 ProgramStateRef State = C.getState();
2862 SymbolRef Sym = State->getSVal(*IVarLoc).getAsSymbol();
2863 if (!Sym || !dyn_cast_or_null<ObjCIvarRegion>(Sym->getOriginRegion()))
2866 // Accessing an ivar directly is unusual. If we've done that, be more
2867 // forgiving about what the surrounding code is allowed to do.
2869 QualType Ty = Sym->getType();
2870 RetEffect::ObjKind Kind;
2871 if (Ty->isObjCRetainableType())
2872 Kind = RetEffect::ObjC;
2873 else if (coreFoundation::isCFObjectRef(Ty))
2874 Kind = RetEffect::CF;
2878 // If the value is already known to be nil, don't bother tracking it.
2879 ConstraintManager &CMgr = State->getConstraintManager();
2880 if (CMgr.isNull(State, Sym).isConstrainedTrue())
2883 if (const RefVal *RV = getRefBinding(State, Sym)) {
2884 // If we've seen this symbol before, or we're only seeing it now because
2885 // of something the analyzer has synthesized, don't do anything.
2886 if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None ||
2887 isSynthesizedAccessor(C.getStackFrame())) {
2891 // Note that this value has been loaded from an ivar.
2892 C.addTransition(setRefBinding(State, Sym, RV->withIvarAccess()));
2896 RefVal PlusZero = RefVal::makeNotOwned(Kind, Ty);
2898 // In a synthesized accessor, the effective retain count is +0.
2899 if (isSynthesizedAccessor(C.getStackFrame())) {
2900 C.addTransition(setRefBinding(State, Sym, PlusZero));
2904 State = setRefBinding(State, Sym, PlusZero.withIvarAccess());
2905 C.addTransition(State);
2908 void RetainCountChecker::checkPostCall(const CallEvent &Call,
2909 CheckerContext &C) const {
2910 RetainSummaryManager &Summaries = getSummaryManager(C);
2911 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState());
2914 processSummaryOfInlined(*Summ, Call, C);
2917 checkSummary(*Summ, Call, C);
2920 /// GetReturnType - Used to get the return type of a message expression or
2921 /// function call with the intention of affixing that type to a tracked symbol.
2922 /// While the return type can be queried directly from RetEx, when
2923 /// invoking class methods we augment to the return type to be that of
2924 /// a pointer to the class (as opposed it just being id).
2925 // FIXME: We may be able to do this with related result types instead.
2926 // This function is probably overestimating.
2927 static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) {
2928 QualType RetTy = RetE->getType();
2929 // If RetE is not a message expression just return its type.
2930 // If RetE is a message expression, return its types if it is something
2931 /// more specific than id.
2932 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE))
2933 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>())
2934 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() ||
2935 PT->isObjCClassType()) {
2936 // At this point we know the return type of the message expression is
2937 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this
2938 // is a call to a class method whose type we can resolve. In such
2939 // cases, promote the return type to XXX* (where XXX is the class).
2940 const ObjCInterfaceDecl *D = ME->getReceiverInterface();
2942 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D));
2948 // We don't always get the exact modeling of the function with regards to the
2949 // retain count checker even when the function is inlined. For example, we need
2950 // to stop tracking the symbols which were marked with StopTrackingHard.
2951 void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ,
2952 const CallEvent &CallOrMsg,
2953 CheckerContext &C) const {
2954 ProgramStateRef state = C.getState();
2956 // Evaluate the effect of the arguments.
2957 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
2958 if (Summ.getArg(idx) == StopTrackingHard) {
2959 SVal V = CallOrMsg.getArgSVal(idx);
2960 if (SymbolRef Sym = V.getAsLocSymbol()) {
2961 state = removeRefBinding(state, Sym);
2966 // Evaluate the effect on the message receiver.
2967 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
2968 if (MsgInvocation) {
2969 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
2970 if (Summ.getReceiverEffect() == StopTrackingHard) {
2971 state = removeRefBinding(state, Sym);
2976 // Consult the summary for the return value.
2977 RetEffect RE = Summ.getRetEffect();
2978 if (RE.getKind() == RetEffect::NoRetHard) {
2979 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
2981 state = removeRefBinding(state, Sym);
2984 C.addTransition(state);
2987 static ProgramStateRef updateOutParameter(ProgramStateRef State,
2990 auto *ArgRegion = dyn_cast_or_null<TypedValueRegion>(ArgVal.getAsRegion());
2994 QualType PointeeTy = ArgRegion->getValueType();
2995 if (!coreFoundation::isCFObjectRef(PointeeTy))
2998 SVal PointeeVal = State->getSVal(ArgRegion);
2999 SymbolRef Pointee = PointeeVal.getAsLocSymbol();
3004 case UnretainedOutParameter:
3005 State = setRefBinding(State, Pointee,
3006 RefVal::makeNotOwned(RetEffect::CF, PointeeTy));
3008 case RetainedOutParameter:
3009 // Do nothing. Retained out parameters will either point to a +1 reference
3010 // or NULL, but the way you check for failure differs depending on the API.
3011 // Consequently, we don't have a good way to track them yet.
3015 llvm_unreachable("only for out parameters");
3021 void RetainCountChecker::checkSummary(const RetainSummary &Summ,
3022 const CallEvent &CallOrMsg,
3023 CheckerContext &C) const {
3024 ProgramStateRef state = C.getState();
3026 // Evaluate the effect of the arguments.
3027 RefVal::Kind hasErr = (RefVal::Kind) 0;
3028 SourceRange ErrorRange;
3029 SymbolRef ErrorSym = nullptr;
3031 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) {
3032 SVal V = CallOrMsg.getArgSVal(idx);
3034 ArgEffect Effect = Summ.getArg(idx);
3035 if (Effect == RetainedOutParameter || Effect == UnretainedOutParameter) {
3036 state = updateOutParameter(state, V, Effect);
3037 } else if (SymbolRef Sym = V.getAsLocSymbol()) {
3038 if (const RefVal *T = getRefBinding(state, Sym)) {
3039 state = updateSymbol(state, Sym, *T, Effect, hasErr, C);
3041 ErrorRange = CallOrMsg.getArgSourceRange(idx);
3049 // Evaluate the effect on the message receiver.
3050 bool ReceiverIsTracked = false;
3052 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg);
3053 if (MsgInvocation) {
3054 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) {
3055 if (const RefVal *T = getRefBinding(state, Sym)) {
3056 ReceiverIsTracked = true;
3057 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(),
3060 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange();
3068 // Process any errors.
3070 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C);
3074 // Consult the summary for the return value.
3075 RetEffect RE = Summ.getRetEffect();
3077 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) {
3078 if (ReceiverIsTracked)
3079 RE = getSummaryManager(C).getObjAllocRetEffect();
3081 RE = RetEffect::MakeNoRet();
3084 switch (RE.getKind()) {
3086 llvm_unreachable("Unhandled RetEffect.");
3088 case RetEffect::NoRet:
3089 case RetEffect::NoRetHard:
3090 // No work necessary.
3093 case RetEffect::OwnedSymbol: {
3094 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
3098 // Use the result type from the CallEvent as it automatically adjusts
3099 // for methods/functions that return references.
3100 QualType ResultTy = CallOrMsg.getResultType();
3101 state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(),
3104 // FIXME: Add a flag to the checker where allocations are assumed to
3109 case RetEffect::GCNotOwnedSymbol:
3110 case RetEffect::NotOwnedSymbol: {
3111 const Expr *Ex = CallOrMsg.getOriginExpr();
3112 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol();
3116 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *.
3117 QualType ResultTy = GetReturnType(Ex, C.getASTContext());
3118 state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(),
3124 // This check is actually necessary; otherwise the statement builder thinks
3125 // we've hit a previously-found path.
3126 // Normally addTransition takes care of this, but we want the node pointer.
3127 ExplodedNode *NewNode;
3128 if (state == C.getState()) {
3129 NewNode = C.getPredecessor();
3131 NewNode = C.addTransition(state);
3134 // Annotate the node with summary we used.
3136 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary.
3137 if (ShouldResetSummaryLog) {
3139 ShouldResetSummaryLog = false;
3141 SummaryLog[NewNode] = &Summ;
3146 RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym,
3147 RefVal V, ArgEffect E, RefVal::Kind &hasErr,
3148 CheckerContext &C) const {
3149 // In GC mode [... release] and [... retain] do nothing.
3150 // In ARC mode they shouldn't exist at all, but we just ignore them.
3151 bool IgnoreRetainMsg = C.isObjCGCEnabled();
3152 if (!IgnoreRetainMsg)
3153 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount;
3159 E = IgnoreRetainMsg ? DoNothing : IncRef;
3162 E = IgnoreRetainMsg ? DoNothing : DecRef;
3164 case DecRefMsgAndStopTrackingHard:
3165 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard;
3167 case MakeCollectable:
3168 E = C.isObjCGCEnabled() ? DecRef : DoNothing;
3172 // Handle all use-after-releases.
3173 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) {
3174 V = V ^ RefVal::ErrorUseAfterRelease;
3175 hasErr = V.getKind();
3176 return setRefBinding(state, sym, V);
3182 case MakeCollectable:
3183 case DecRefMsgAndStopTrackingHard:
3184 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted");
3186 case UnretainedOutParameter:
3187 case RetainedOutParameter:
3188 llvm_unreachable("Applies to pointer-to-pointer parameters, which should "
3189 "not have ref state.");
3192 // Any use of -dealloc in GC is *bad*.
3193 if (C.isObjCGCEnabled()) {
3194 V = V ^ RefVal::ErrorDeallocGC;
3195 hasErr = V.getKind();
3199 switch (V.getKind()) {
3201 llvm_unreachable("Invalid RefVal state for an explicit dealloc.");
3203 // The object immediately transitions to the released state.
3204 V = V ^ RefVal::Released;
3206 return setRefBinding(state, sym, V);
3207 case RefVal::NotOwned:
3208 V = V ^ RefVal::ErrorDeallocNotOwned;
3209 hasErr = V.getKind();
3215 if (V.getKind() == RefVal::Owned) {
3216 V = V ^ RefVal::NotOwned;
3226 if (C.isObjCGCEnabled())
3228 // Update the autorelease counts.
3229 V = V.autorelease();
3233 case StopTrackingHard:
3234 return removeRefBinding(state, sym);
3237 switch (V.getKind()) {
3239 llvm_unreachable("Invalid RefVal state for a retain.");
3241 case RefVal::NotOwned:
3244 case RefVal::Released:
3245 // Non-GC cases are handled above.
3246 assert(C.isObjCGCEnabled());
3247 V = (V ^ RefVal::Owned) + 1;
3253 case DecRefBridgedTransferred:
3254 case DecRefAndStopTrackingHard:
3255 switch (V.getKind()) {
3257 // case 'RefVal::Released' handled above.
3258 llvm_unreachable("Invalid RefVal state for a release.");
3261 assert(V.getCount() > 0);
3262 if (V.getCount() == 1) {
3263 if (E == DecRefBridgedTransferred ||
3264 V.getIvarAccessHistory() ==
3265 RefVal::IvarAccessHistory::AccessedDirectly)
3266 V = V ^ RefVal::NotOwned;
3268 V = V ^ RefVal::Released;
3269 } else if (E == DecRefAndStopTrackingHard) {
3270 return removeRefBinding(state, sym);
3276 case RefVal::NotOwned:
3277 if (V.getCount() > 0) {
3278 if (E == DecRefAndStopTrackingHard)
3279 return removeRefBinding(state, sym);
3281 } else if (V.getIvarAccessHistory() ==
3282 RefVal::IvarAccessHistory::AccessedDirectly) {
3283 // Assume that the instance variable was holding on the object at
3284 // +1, and we just didn't know.
3285 if (E == DecRefAndStopTrackingHard)
3286 return removeRefBinding(state, sym);
3287 V = V.releaseViaIvar() ^ RefVal::Released;
3289 V = V ^ RefVal::ErrorReleaseNotOwned;
3290 hasErr = V.getKind();
3294 case RefVal::Released:
3295 // Non-GC cases are handled above.
3296 assert(C.isObjCGCEnabled());
3297 V = V ^ RefVal::ErrorUseAfterRelease;
3298 hasErr = V.getKind();
3303 return setRefBinding(state, sym, V);
3306 void RetainCountChecker::processNonLeakError(ProgramStateRef St,
3307 SourceRange ErrorRange,
3308 RefVal::Kind ErrorKind,
3310 CheckerContext &C) const {
3311 // HACK: Ignore retain-count issues on values accessed through ivars,
3312 // because of cases like this:
3313 // [_contentView retain];
3314 // [_contentView removeFromSuperview];
3315 // [self addSubview:_contentView]; // invalidates 'self'
3316 // [_contentView release];
3317 if (const RefVal *RV = getRefBinding(St, Sym))
3318 if (RV->getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3321 ExplodedNode *N = C.generateErrorNode(St);
3326 switch (ErrorKind) {
3328 llvm_unreachable("Unhandled error.");
3329 case RefVal::ErrorUseAfterRelease:
3330 if (!useAfterRelease)
3331 useAfterRelease.reset(new UseAfterRelease(this));
3332 BT = useAfterRelease.get();
3334 case RefVal::ErrorReleaseNotOwned:
3335 if (!releaseNotOwned)
3336 releaseNotOwned.reset(new BadRelease(this));
3337 BT = releaseNotOwned.get();
3339 case RefVal::ErrorDeallocGC:
3341 deallocGC.reset(new DeallocGC(this));
3342 BT = deallocGC.get();
3344 case RefVal::ErrorDeallocNotOwned:
3345 if (!deallocNotOwned)
3346 deallocNotOwned.reset(new DeallocNotOwned(this));
3347 BT = deallocNotOwned.get();
3352 auto report = std::unique_ptr<BugReport>(
3353 new CFRefReport(*BT, C.getASTContext().getLangOpts(), C.isObjCGCEnabled(),
3354 SummaryLog, N, Sym));
3355 report->addRange(ErrorRange);
3356 C.emitReport(std::move(report));
3359 //===----------------------------------------------------------------------===//
3360 // Handle the return values of retain-count-related functions.
3361 //===----------------------------------------------------------------------===//
3363 bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
3364 // Get the callee. We're only interested in simple C functions.
3365 ProgramStateRef state = C.getState();
3366 const FunctionDecl *FD = C.getCalleeDecl(CE);
3370 IdentifierInfo *II = FD->getIdentifier();
3374 // For now, we're only handling the functions that return aliases of their
3375 // arguments: CFRetain and CFMakeCollectable (and their families).
3376 // Eventually we should add other functions we can model entirely,
3377 // such as CFRelease, which don't invalidate their arguments or globals.
3378 if (CE->getNumArgs() != 1)
3381 // Get the name of the function.
3382 StringRef FName = II->getName();
3383 FName = FName.substr(FName.find_first_not_of('_'));
3385 // See if it's one of the specific functions we know how to eval.
3386 bool canEval = false;
3388 QualType ResultTy = CE->getCallReturnType(C.getASTContext());
3389 if (ResultTy->isObjCIdType()) {
3390 // Handle: id NSMakeCollectable(CFTypeRef)
3391 canEval = II->isStr("NSMakeCollectable");
3392 } else if (ResultTy->isPointerType()) {
3393 // Handle: (CF|CG|CV)Retain
3395 // CFMakeCollectable
3396 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist).
3397 if (cocoa::isRefType(ResultTy, "CF", FName) ||
3398 cocoa::isRefType(ResultTy, "CG", FName) ||
3399 cocoa::isRefType(ResultTy, "CV", FName)) {
3400 canEval = isRetain(FD, FName) || isAutorelease(FD, FName) ||
3401 isMakeCollectable(FD, FName);
3408 // Bind the return value.
3409 const LocationContext *LCtx = C.getLocationContext();
3410 SVal RetVal = state->getSVal(CE->getArg(0), LCtx);
3411 if (RetVal.isUnknown()) {
3412 // If the receiver is unknown, conjure a return value.
3413 SValBuilder &SVB = C.getSValBuilder();
3414 RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, ResultTy, C.blockCount());
3416 state = state->BindExpr(CE, LCtx, RetVal, false);
3418 // FIXME: This should not be necessary, but otherwise the argument seems to be
3419 // considered alive during the next statement.
3420 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) {
3421 // Save the refcount status of the argument.
3422 SymbolRef Sym = RetVal.getAsLocSymbol();
3423 const RefVal *Binding = nullptr;
3425 Binding = getRefBinding(state, Sym);
3427 // Invalidate the argument region.
3428 state = state->invalidateRegions(ArgRegion, CE, C.blockCount(), LCtx,
3429 /*CausesPointerEscape*/ false);
3431 // Restore the refcount status of the argument.
3433 state = setRefBinding(state, Sym, *Binding);
3436 C.addTransition(state);
3440 //===----------------------------------------------------------------------===//
3441 // Handle return statements.
3442 //===----------------------------------------------------------------------===//
3444 void RetainCountChecker::checkPreStmt(const ReturnStmt *S,
3445 CheckerContext &C) const {
3447 // Only adjust the reference count if this is the top-level call frame,
3448 // and not the result of inlining. In the future, we should do
3449 // better checking even for inlined calls, and see if they match
3450 // with their expected semantics (e.g., the method should return a retained
3452 if (!C.inTopFrame())
3455 const Expr *RetE = S->getRetValue();
3459 ProgramStateRef state = C.getState();
3461 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol();
3465 // Get the reference count binding (if any).
3466 const RefVal *T = getRefBinding(state, Sym);
3470 // Change the reference count.
3473 switch (X.getKind()) {
3474 case RefVal::Owned: {
3475 unsigned cnt = X.getCount();
3477 X.setCount(cnt - 1);
3478 X = X ^ RefVal::ReturnedOwned;
3482 case RefVal::NotOwned: {
3483 unsigned cnt = X.getCount();
3485 X.setCount(cnt - 1);
3486 X = X ^ RefVal::ReturnedOwned;
3489 X = X ^ RefVal::ReturnedNotOwned;
3498 // Update the binding.
3499 state = setRefBinding(state, Sym, X);
3500 ExplodedNode *Pred = C.addTransition(state);
3502 // At this point we have updated the state properly.
3503 // Everything after this is merely checking to see if the return value has
3504 // been over- or under-retained.
3506 // Did we cache out?
3510 // Update the autorelease counts.
3511 static CheckerProgramPointTag AutoreleaseTag(this, "Autorelease");
3512 state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X);
3514 // Did we cache out?
3518 // Get the updated binding.
3519 T = getRefBinding(state, Sym);
3523 // Consult the summary of the enclosing method.
3524 RetainSummaryManager &Summaries = getSummaryManager(C);
3525 const Decl *CD = &Pred->getCodeDecl();
3526 RetEffect RE = RetEffect::MakeNoRet();
3528 // FIXME: What is the convention for blocks? Is there one?
3529 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) {
3530 const RetainSummary *Summ = Summaries.getMethodSummary(MD);
3531 RE = Summ->getRetEffect();
3532 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) {
3533 if (!isa<CXXMethodDecl>(FD)) {
3534 const RetainSummary *Summ = Summaries.getFunctionSummary(FD);
3535 RE = Summ->getRetEffect();
3539 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state);
3542 void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S,
3545 RetEffect RE, RefVal X,
3547 ProgramStateRef state) const {
3548 // HACK: Ignore retain-count issues on values accessed through ivars,
3549 // because of cases like this:
3550 // [_contentView retain];
3551 // [_contentView removeFromSuperview];
3552 // [self addSubview:_contentView]; // invalidates 'self'
3553 // [_contentView release];
3554 if (X.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3557 // Any leaks or other errors?
3558 if (X.isReturnedOwned() && X.getCount() == 0) {
3559 if (RE.getKind() != RetEffect::NoRet) {
3560 bool hasError = false;
3561 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) {
3562 // Things are more complicated with garbage collection. If the
3563 // returned object is suppose to be an Objective-C object, we have
3564 // a leak (as the caller expects a GC'ed object) because no
3565 // method should return ownership unless it returns a CF object.
3567 X = X ^ RefVal::ErrorGCLeakReturned;
3569 else if (!RE.isOwned()) {
3570 // Either we are using GC and the returned object is a CF type
3571 // or we aren't using GC. In either case, we expect that the
3572 // enclosing method is expected to return ownership.
3574 X = X ^ RefVal::ErrorLeakReturned;
3578 // Generate an error node.
3579 state = setRefBinding(state, Sym, X);
3581 static CheckerProgramPointTag ReturnOwnLeakTag(this, "ReturnsOwnLeak");
3582 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag);
3584 const LangOptions &LOpts = C.getASTContext().getLangOpts();
3585 bool GCEnabled = C.isObjCGCEnabled();
3586 C.emitReport(std::unique_ptr<BugReport>(new CFRefLeakReport(
3587 *getLeakAtReturnBug(LOpts, GCEnabled), LOpts, GCEnabled,
3588 SummaryLog, N, Sym, C, IncludeAllocationLine)));
3592 } else if (X.isReturnedNotOwned()) {
3594 if (X.getIvarAccessHistory() ==
3595 RefVal::IvarAccessHistory::AccessedDirectly) {
3596 // Assume the method was trying to transfer a +1 reference from a
3597 // strong ivar to the caller.
3598 state = setRefBinding(state, Sym,
3599 X.releaseViaIvar() ^ RefVal::ReturnedOwned);
3601 // Trying to return a not owned object to a caller expecting an
3603 state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned);
3605 static CheckerProgramPointTag
3606 ReturnNotOwnedTag(this, "ReturnNotOwnedForOwned");
3608 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag);
3610 if (!returnNotOwnedForOwned)
3611 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned(this));
3613 C.emitReport(std::unique_ptr<BugReport>(new CFRefReport(
3614 *returnNotOwnedForOwned, C.getASTContext().getLangOpts(),
3615 C.isObjCGCEnabled(), SummaryLog, N, Sym)));
3622 //===----------------------------------------------------------------------===//
3623 // Check various ways a symbol can be invalidated.
3624 //===----------------------------------------------------------------------===//
3626 void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S,
3627 CheckerContext &C) const {
3628 // Are we storing to something that causes the value to "escape"?
3629 bool escapes = true;
3631 // A value escapes in three possible cases (this may change):
3633 // (1) we are binding to something that is not a memory region.
3634 // (2) we are binding to a memregion that does not have stack storage
3635 // (3) we are binding to a memregion with stack storage that the store
3636 // does not understand.
3637 ProgramStateRef state = C.getState();
3639 if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) {
3640 escapes = !regionLoc->getRegion()->hasStackStorage();
3643 // To test (3), generate a new state with the binding added. If it is
3644 // the same state, then it escapes (since the store cannot represent
3646 // Do this only if we know that the store is not supposed to generate the
3648 SVal StoredVal = state->getSVal(regionLoc->getRegion());
3649 if (StoredVal != val)
3650 escapes = (state == (state->bindLoc(*regionLoc, val)));
3653 // Case 4: We do not currently model what happens when a symbol is
3654 // assigned to a struct field, so be conservative here and let the symbol
3655 // go. TODO: This could definitely be improved upon.
3656 escapes = !isa<VarRegion>(regionLoc->getRegion());
3660 // If we are storing the value into an auto function scope variable annotated
3661 // with (__attribute__((cleanup))), stop tracking the value to avoid leak
3663 if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) {
3664 const VarDecl *VD = LVR->getDecl();
3665 if (VD->hasAttr<CleanupAttr>()) {
3670 // If our store can represent the binding and we aren't storing to something
3671 // that doesn't have local storage then just return and have the simulation
3672 // state continue as is.
3676 // Otherwise, find all symbols referenced by 'val' that we are tracking
3677 // and stop tracking them.
3678 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState();
3679 C.addTransition(state);
3682 ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state,
3684 bool Assumption) const {
3685 // FIXME: We may add to the interface of evalAssume the list of symbols
3686 // whose assumptions have changed. For now we just iterate through the
3687 // bindings and check if any of the tracked symbols are NULL. This isn't
3688 // too bad since the number of symbols we will track in practice are
3689 // probably small and evalAssume is only called at branches and a few
3691 RefBindingsTy B = state->get<RefBindings>();
3696 bool changed = false;
3697 RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>();
3699 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
3700 // Check if the symbol is null stop tracking the symbol.
3701 ConstraintManager &CMgr = state->getConstraintManager();
3702 ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey());
3703 if (AllocFailed.isConstrainedTrue()) {
3705 B = RefBFactory.remove(B, I.getKey());
3710 state = state->set<RefBindings>(B);
3716 RetainCountChecker::checkRegionChanges(ProgramStateRef state,
3717 const InvalidatedSymbols *invalidated,
3718 ArrayRef<const MemRegion *> ExplicitRegions,
3719 ArrayRef<const MemRegion *> Regions,
3720 const CallEvent *Call) const {
3724 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols;
3725 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
3726 E = ExplicitRegions.end(); I != E; ++I) {
3727 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>())
3728 WhitelistedSymbols.insert(SR->getSymbol());
3731 for (InvalidatedSymbols::const_iterator I=invalidated->begin(),
3732 E = invalidated->end(); I!=E; ++I) {
3734 if (WhitelistedSymbols.count(sym))
3736 // Remove any existing reference-count binding.
3737 state = removeRefBinding(state, sym);
3742 //===----------------------------------------------------------------------===//
3743 // Handle dead symbols and end-of-path.
3744 //===----------------------------------------------------------------------===//
3747 RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state,
3749 const ProgramPointTag *Tag,
3750 CheckerContext &Ctx,
3751 SymbolRef Sym, RefVal V) const {
3752 unsigned ACnt = V.getAutoreleaseCount();
3754 // No autorelease counts? Nothing to be done.
3758 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?");
3759 unsigned Cnt = V.getCount();
3761 // FIXME: Handle sending 'autorelease' to already released object.
3763 if (V.getKind() == RefVal::ReturnedOwned)
3766 // If we would over-release here, but we know the value came from an ivar,
3767 // assume it was a strong ivar that's just been relinquished.
3769 V.getIvarAccessHistory() == RefVal::IvarAccessHistory::AccessedDirectly) {
3770 V = V.releaseViaIvar();
3777 if (V.getKind() == RefVal::ReturnedOwned)
3778 V = V ^ RefVal::ReturnedNotOwned;
3780 V = V ^ RefVal::NotOwned;
3782 V.setCount(V.getCount() - ACnt);
3783 V.setAutoreleaseCount(0);
3785 return setRefBinding(state, Sym, V);
3788 // HACK: Ignore retain-count issues on values accessed through ivars,
3789 // because of cases like this:
3790 // [_contentView retain];
3791 // [_contentView removeFromSuperview];
3792 // [self addSubview:_contentView]; // invalidates 'self'
3793 // [_contentView release];
3794 if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3797 // Woah! More autorelease counts then retain counts left.
3799 V = V ^ RefVal::ErrorOverAutorelease;
3800 state = setRefBinding(state, Sym, V);
3802 ExplodedNode *N = Ctx.generateSink(state, Pred, Tag);
3804 SmallString<128> sbuf;
3805 llvm::raw_svector_ostream os(sbuf);
3806 os << "Object was autoreleased ";
3807 if (V.getAutoreleaseCount() > 1)
3808 os << V.getAutoreleaseCount() << " times but the object ";
3811 os << "has a +" << V.getCount() << " retain count";
3813 if (!overAutorelease)
3814 overAutorelease.reset(new OverAutorelease(this));
3816 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
3817 Ctx.emitReport(std::unique_ptr<BugReport>(
3818 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false,
3819 SummaryLog, N, Sym, os.str())));
3826 RetainCountChecker::handleSymbolDeath(ProgramStateRef state,
3827 SymbolRef sid, RefVal V,
3828 SmallVectorImpl<SymbolRef> &Leaked) const {
3831 // HACK: Ignore retain-count issues on values accessed through ivars,
3832 // because of cases like this:
3833 // [_contentView retain];
3834 // [_contentView removeFromSuperview];
3835 // [self addSubview:_contentView]; // invalidates 'self'
3836 // [_contentView release];
3837 if (V.getIvarAccessHistory() != RefVal::IvarAccessHistory::None)
3839 else if (V.isOwned())
3841 else if (V.isNotOwned() || V.isReturnedOwned())
3842 hasLeak = (V.getCount() > 0);
3847 return removeRefBinding(state, sid);
3849 Leaked.push_back(sid);
3850 return setRefBinding(state, sid, V ^ RefVal::ErrorLeak);
3854 RetainCountChecker::processLeaks(ProgramStateRef state,
3855 SmallVectorImpl<SymbolRef> &Leaked,
3856 CheckerContext &Ctx,
3857 ExplodedNode *Pred) const {
3858 // Generate an intermediate node representing the leak point.
3859 ExplodedNode *N = Ctx.addTransition(state, Pred);
3862 for (SmallVectorImpl<SymbolRef>::iterator
3863 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) {
3865 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts();
3866 bool GCEnabled = Ctx.isObjCGCEnabled();
3867 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled)
3868 : getLeakAtReturnBug(LOpts, GCEnabled);
3869 assert(BT && "BugType not initialized.");
3871 Ctx.emitReport(std::unique_ptr<BugReport>(
3872 new CFRefLeakReport(*BT, LOpts, GCEnabled, SummaryLog, N, *I, Ctx,
3873 IncludeAllocationLine)));
3880 void RetainCountChecker::checkEndFunction(CheckerContext &Ctx) const {
3881 ProgramStateRef state = Ctx.getState();
3882 RefBindingsTy B = state->get<RefBindings>();
3883 ExplodedNode *Pred = Ctx.getPredecessor();
3885 // Don't process anything within synthesized bodies.
3886 const LocationContext *LCtx = Pred->getLocationContext();
3887 if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) {
3888 assert(!LCtx->inTopFrame());
3892 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
3893 state = handleAutoreleaseCounts(state, Pred, /*Tag=*/nullptr, Ctx,
3894 I->first, I->second);
3899 // If the current LocationContext has a parent, don't check for leaks.
3900 // We will do that later.
3901 // FIXME: we should instead check for imbalances of the retain/releases,
3902 // and suggest annotations.
3903 if (LCtx->getParent())
3906 B = state->get<RefBindings>();
3907 SmallVector<SymbolRef, 10> Leaked;
3909 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I)
3910 state = handleSymbolDeath(state, I->first, I->second, Leaked);
3912 processLeaks(state, Leaked, Ctx, Pred);
3915 const ProgramPointTag *
3916 RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const {
3917 const CheckerProgramPointTag *&tag = DeadSymbolTags[sym];
3919 SmallString<64> buf;
3920 llvm::raw_svector_ostream out(buf);
3921 out << "Dead Symbol : ";
3922 sym->dumpToStream(out);
3923 tag = new CheckerProgramPointTag(this, out.str());
3928 void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper,
3929 CheckerContext &C) const {
3930 ExplodedNode *Pred = C.getPredecessor();
3932 ProgramStateRef state = C.getState();
3933 RefBindingsTy B = state->get<RefBindings>();
3934 SmallVector<SymbolRef, 10> Leaked;
3936 // Update counts from autorelease pools
3937 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
3938 E = SymReaper.dead_end(); I != E; ++I) {
3940 if (const RefVal *T = B.lookup(Sym)){
3941 // Use the symbol as the tag.
3942 // FIXME: This might not be as unique as we would like.
3943 const ProgramPointTag *Tag = getDeadSymbolTag(Sym);
3944 state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T);
3948 // Fetch the new reference count from the state, and use it to handle
3950 state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked);
3954 if (Leaked.empty()) {
3955 C.addTransition(state);
3959 Pred = processLeaks(state, Leaked, C, Pred);
3961 // Did we cache out?
3965 // Now generate a new node that nukes the old bindings.
3966 // The only bindings left at this point are the leaked symbols.
3967 RefBindingsTy::Factory &F = state->get_context<RefBindings>();
3968 B = state->get<RefBindings>();
3970 for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(),
3973 B = F.remove(B, *I);
3975 state = state->set<RefBindings>(B);
3976 C.addTransition(state, Pred);
3979 void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State,
3980 const char *NL, const char *Sep) const {
3982 RefBindingsTy B = State->get<RefBindings>();
3989 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) {
3990 Out << I->first << " : ";
3991 I->second.print(Out);
3996 //===----------------------------------------------------------------------===//
3997 // Checker registration.
3998 //===----------------------------------------------------------------------===//
4000 void ento::registerRetainCountChecker(CheckerManager &Mgr) {
4001 Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions());
4004 //===----------------------------------------------------------------------===//
4005 // Implementation of the CallEffects API.
4006 //===----------------------------------------------------------------------===//
4010 namespace objc_retain {
4012 // This is a bit gross, but it allows us to populate CallEffects without
4013 // creating a bunch of accessors. This kind is very localized, so the
4014 // damage of this macro is limited.
4015 #define createCallEffect(D, KIND)\
4016 ASTContext &Ctx = D->getASTContext();\
4017 LangOptions L = Ctx.getLangOpts();\
4018 RetainSummaryManager M(Ctx, L.GCOnly, L.ObjCAutoRefCount);\
4019 const RetainSummary *S = M.get ## KIND ## Summary(D);\
4020 CallEffects CE(S->getRetEffect());\
4021 CE.Receiver = S->getReceiverEffect();\
4022 unsigned N = D->param_size();\
4023 for (unsigned i = 0; i < N; ++i) {\
4024 CE.Args.push_back(S->getArg(i));\
4027 CallEffects CallEffects::getEffect(const ObjCMethodDecl *MD) {
4028 createCallEffect(MD, Method);
4032 CallEffects CallEffects::getEffect(const FunctionDecl *FD) {
4033 createCallEffect(FD, Function);
4037 #undef createCallEffect
4039 } // end namespace objc_retain
4040 } // end namespace ento
4041 } // end namespace clang