1 //==--- RetainCountChecker.h - Checks for leaks and other issues -*- C++ -*--//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file defines the methods for RetainCountChecker, which implements
10 // a reference count checker for Core Foundation and Cocoa on (Mac OS X).
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_H
15 #define LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_RETAINCOUNTCHECKER_H
17 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
18 #include "RetainCountDiagnostics.h"
19 #include "clang/AST/Attr.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclObjC.h"
22 #include "clang/AST/ParentMap.h"
23 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
24 #include "clang/Analysis/PathDiagnostic.h"
25 #include "clang/Analysis/RetainSummaryManager.h"
26 #include "clang/Basic/LangOptions.h"
27 #include "clang/Basic/SourceManager.h"
28 #include "clang/Analysis/SelectorExtras.h"
29 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
30 #include "clang/StaticAnalyzer/Core/Checker.h"
31 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
32 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
33 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
34 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
35 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
36 #include "llvm/ADT/DenseMap.h"
37 #include "llvm/ADT/FoldingSet.h"
38 #include "llvm/ADT/ImmutableList.h"
39 #include "llvm/ADT/ImmutableMap.h"
40 #include "llvm/ADT/STLExtras.h"
41 #include "llvm/ADT/SmallString.h"
42 #include "llvm/ADT/StringExtras.h"
48 namespace retaincountchecker {
50 /// Metadata on reference.
54 Owned = 0, // Owning reference.
55 NotOwned, // Reference is not owned by still valid (not freed).
56 Released, // Object has been released.
57 ReturnedOwned, // Returned object passes ownership to caller.
58 ReturnedNotOwned, // Return object does not pass ownership to caller.
60 ErrorDeallocNotOwned, // -dealloc called on non-owned object.
61 ErrorUseAfterRelease, // Object used after released.
62 ErrorReleaseNotOwned, // Release of an object that was not owned.
64 ErrorLeak, // A memory leak due to excessive reference counts.
65 ErrorLeakReturned, // A memory leak due to the returning method not having
66 // the correct naming conventions.
71 /// Tracks how an object referenced by an ivar has been used.
73 /// This accounts for us not knowing if an arbitrary ivar is supposed to be
74 /// stored at +0 or +1.
75 enum class IvarAccessHistory {
78 ReleasedAfterDirectAccess
82 /// The number of outstanding retains.
84 /// The number of outstanding autoreleases.
86 /// The (static) type of the object at the time we started tracking it.
89 /// The current state of the object.
91 /// See the RefVal::Kind enum for possible values.
94 /// The kind of object being tracked (CF or ObjC or OSObject), if known.
96 /// See the ObjKind enum for possible values.
97 unsigned RawObjectKind : 3;
99 /// True if the current state and/or retain count may turn out to not be the
100 /// best possible approximation of the reference counting state.
102 /// If true, the checker may decide to throw away ("override") this state
103 /// in favor of something else when it sees the object being used in new ways.
105 /// This setting should not be propagated to state derived from this state.
106 /// Once we start deriving new states, it would be inconsistent to override
108 unsigned RawIvarAccessHistory : 2;
110 RefVal(Kind k, ObjKind o, unsigned cnt, unsigned acnt, QualType t,
111 IvarAccessHistory IvarAccess)
112 : Cnt(cnt), ACnt(acnt), T(t), RawKind(static_cast<unsigned>(k)),
113 RawObjectKind(static_cast<unsigned>(o)),
114 RawIvarAccessHistory(static_cast<unsigned>(IvarAccess)) {
115 assert(getKind() == k && "not enough bits for the kind");
116 assert(getObjKind() == o && "not enough bits for the object kind");
117 assert(getIvarAccessHistory() == IvarAccess && "not enough bits");
121 Kind getKind() const { return static_cast<Kind>(RawKind); }
123 ObjKind getObjKind() const {
124 return static_cast<ObjKind>(RawObjectKind);
127 unsigned getCount() const { return Cnt; }
128 unsigned getAutoreleaseCount() const { return ACnt; }
129 unsigned getCombinedCounts() const { return Cnt + ACnt; }
134 void setCount(unsigned i) {
137 void setAutoreleaseCount(unsigned i) {
141 QualType getType() const { return T; }
143 /// Returns what the analyzer knows about direct accesses to a particular
144 /// instance variable.
146 /// If the object with this refcount wasn't originally from an Objective-C
147 /// ivar region, this should always return IvarAccessHistory::None.
148 IvarAccessHistory getIvarAccessHistory() const {
149 return static_cast<IvarAccessHistory>(RawIvarAccessHistory);
152 bool isOwned() const {
153 return getKind() == Owned;
156 bool isNotOwned() const {
157 return getKind() == NotOwned;
160 bool isReturnedOwned() const {
161 return getKind() == ReturnedOwned;
164 bool isReturnedNotOwned() const {
165 return getKind() == ReturnedNotOwned;
168 /// Create a state for an object whose lifetime is the responsibility of the
169 /// current function, at least partially.
171 /// Most commonly, this is an owned object with a retain count of +1.
172 static RefVal makeOwned(ObjKind o, QualType t) {
173 return RefVal(Owned, o, /*Count=*/1, 0, t, IvarAccessHistory::None);
176 /// Create a state for an object whose lifetime is not the responsibility of
177 /// the current function.
179 /// Most commonly, this is an unowned object with a retain count of +0.
180 static RefVal makeNotOwned(ObjKind o, QualType t) {
181 return RefVal(NotOwned, o, /*Count=*/0, 0, t, IvarAccessHistory::None);
184 RefVal operator-(size_t i) const {
185 return RefVal(getKind(), getObjKind(), getCount() - i,
186 getAutoreleaseCount(), getType(), getIvarAccessHistory());
189 RefVal operator+(size_t i) const {
190 return RefVal(getKind(), getObjKind(), getCount() + i,
191 getAutoreleaseCount(), getType(), getIvarAccessHistory());
194 RefVal operator^(Kind k) const {
195 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(),
196 getType(), getIvarAccessHistory());
199 RefVal autorelease() const {
200 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1,
201 getType(), getIvarAccessHistory());
204 RefVal withIvarAccess() const {
205 assert(getIvarAccessHistory() == IvarAccessHistory::None);
206 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
207 getType(), IvarAccessHistory::AccessedDirectly);
210 RefVal releaseViaIvar() const {
211 assert(getIvarAccessHistory() == IvarAccessHistory::AccessedDirectly);
212 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount(),
213 getType(), IvarAccessHistory::ReleasedAfterDirectAccess);
216 // Comparison, profiling, and pretty-printing.
217 bool hasSameState(const RefVal &X) const {
218 return getKind() == X.getKind() && Cnt == X.Cnt && ACnt == X.ACnt &&
219 getIvarAccessHistory() == X.getIvarAccessHistory();
222 bool operator==(const RefVal& X) const {
223 return T == X.T && hasSameState(X) && getObjKind() == X.getObjKind();
226 void Profile(llvm::FoldingSetNodeID& ID) const {
228 ID.AddInteger(RawKind);
231 ID.AddInteger(RawObjectKind);
232 ID.AddInteger(RawIvarAccessHistory);
235 void print(raw_ostream &Out) const;
238 class RetainCountChecker
239 : public Checker< check::Bind,
241 check::BeginFunction,
243 check::PostStmt<BlockExpr>,
244 check::PostStmt<CastExpr>,
245 check::PostStmt<ObjCArrayLiteral>,
246 check::PostStmt<ObjCDictionaryLiteral>,
247 check::PostStmt<ObjCBoxedExpr>,
248 check::PostStmt<ObjCIvarRefExpr>,
250 check::RegionChanges,
254 RefCountBug useAfterRelease{this, RefCountBug::UseAfterRelease};
255 RefCountBug releaseNotOwned{this, RefCountBug::ReleaseNotOwned};
256 RefCountBug deallocNotOwned{this, RefCountBug::DeallocNotOwned};
257 RefCountBug freeNotOwned{this, RefCountBug::FreeNotOwned};
258 RefCountBug overAutorelease{this, RefCountBug::OverAutorelease};
259 RefCountBug returnNotOwnedForOwned{this, RefCountBug::ReturnNotOwnedForOwned};
260 RefCountBug leakWithinFunction{this, RefCountBug::LeakWithinFunction};
261 RefCountBug leakAtReturn{this, RefCountBug::LeakAtReturn};
263 CheckerProgramPointTag DeallocSentTag{this, "DeallocSent"};
264 CheckerProgramPointTag CastFailTag{this, "DynamicCastFail"};
266 mutable std::unique_ptr<RetainSummaryManager> Summaries;
269 /// Track Objective-C and CoreFoundation objects.
270 bool TrackObjCAndCFObjects = false;
272 /// Track sublcasses of OSObject.
273 bool TrackOSObjects = false;
275 /// Track initial parameters (for the entry point) for NS/CF objects.
276 bool TrackNSCFStartParam = false;
278 RetainCountChecker() {};
280 RetainSummaryManager &getSummaryManager(ASTContext &Ctx) const {
283 new RetainSummaryManager(Ctx, TrackObjCAndCFObjects, TrackOSObjects));
287 RetainSummaryManager &getSummaryManager(CheckerContext &C) const {
288 return getSummaryManager(C.getASTContext());
291 void printState(raw_ostream &Out, ProgramStateRef State,
292 const char *NL, const char *Sep) const override;
294 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const;
295 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const;
296 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const;
298 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const;
299 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const;
300 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const;
302 void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const;
304 void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
306 void checkSummary(const RetainSummary &Summ, const CallEvent &Call,
307 CheckerContext &C) const;
309 void processSummaryOfInlined(const RetainSummary &Summ,
310 const CallEvent &Call,
311 CheckerContext &C) const;
313 bool evalCall(const CallEvent &Call, CheckerContext &C) const;
315 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond,
316 bool Assumption) const;
319 checkRegionChanges(ProgramStateRef state,
320 const InvalidatedSymbols *invalidated,
321 ArrayRef<const MemRegion *> ExplicitRegions,
322 ArrayRef<const MemRegion *> Regions,
323 const LocationContext* LCtx,
324 const CallEvent *Call) const;
326 ExplodedNode* checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C,
327 ExplodedNode *Pred, RetEffect RE, RefVal X,
328 SymbolRef Sym, ProgramStateRef state) const;
330 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
331 void checkBeginFunction(CheckerContext &C) const;
332 void checkEndFunction(const ReturnStmt *RS, CheckerContext &C) const;
334 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym,
335 RefVal V, ArgEffect E, RefVal::Kind &hasErr,
336 CheckerContext &C) const;
338 const RefCountBug &errorKindToBugKind(RefVal::Kind ErrorKind,
339 SymbolRef Sym) const;
341 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange,
342 RefVal::Kind ErrorKind, SymbolRef Sym,
343 CheckerContext &C) const;
345 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const;
347 ProgramStateRef handleSymbolDeath(ProgramStateRef state,
348 SymbolRef sid, RefVal V,
349 SmallVectorImpl<SymbolRef> &Leaked) const;
352 handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred,
353 const ProgramPointTag *Tag, CheckerContext &Ctx,
356 const ReturnStmt *S=nullptr) const;
358 ExplodedNode *processLeaks(ProgramStateRef state,
359 SmallVectorImpl<SymbolRef> &Leaked,
361 ExplodedNode *Pred = nullptr) const;
363 const CheckerProgramPointTag &getDeallocSentTag() const {
364 return DeallocSentTag;
367 const CheckerProgramPointTag &getCastFailTag() const {
372 /// Perform the necessary checks and state adjustments at the end of the
374 /// \p S Return statement, may be null.
375 ExplodedNode * processReturn(const ReturnStmt *S, CheckerContext &C) const;
378 //===----------------------------------------------------------------------===//
379 // RefBindings - State used to track object reference counts.
380 //===----------------------------------------------------------------------===//
382 const RefVal *getRefBinding(ProgramStateRef State, SymbolRef Sym);
384 /// Returns true if this stack frame is for an Objective-C method that is a
385 /// property getter or setter whose body has been synthesized by the analyzer.
386 inline bool isSynthesizedAccessor(const StackFrameContext *SFC) {
387 auto Method = dyn_cast_or_null<ObjCMethodDecl>(SFC->getDecl());
388 if (!Method || !Method->isPropertyAccessor())
391 return SFC->getAnalysisDeclContext()->isBodyAutosynthesized();
394 } // end namespace retaincountchecker
395 } // end namespace ento
396 } // end namespace clang