1 //==-- RetainCountChecker.cpp - Checks for leaks and other issues -*- C++ -*--// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the methods for RetainCountChecker, which implements 11 // a reference count checker for Core Foundation and Cocoa on (Mac OS X). 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "ClangSACheckers.h" 16 #include "AllocationDiagnostics.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" 41 #include <cstdarg> 42 43 using namespace clang; 44 using namespace ento; 45 using namespace objc_retain; 46 using llvm::StrInStrNoCase; 47 48 //===----------------------------------------------------------------------===// 49 // Adapters for FoldingSet. 50 //===----------------------------------------------------------------------===// 51 52 namespace llvm { 53 template <> struct FoldingSetTrait<ArgEffect> { 54 static inline void Profile(const ArgEffect X, FoldingSetNodeID &ID) { 55 ID.AddInteger((unsigned) X); 56 } 57 }; 58 template <> struct FoldingSetTrait<RetEffect> { 59 static inline void Profile(const RetEffect &X, FoldingSetNodeID &ID) { 60 ID.AddInteger((unsigned) X.getKind()); 61 ID.AddInteger((unsigned) X.getObjKind()); 62 } 63 }; 64 } // end llvm namespace 65 66 //===----------------------------------------------------------------------===// 67 // Reference-counting logic (typestate + counts). 68 //===----------------------------------------------------------------------===// 69 70 /// ArgEffects summarizes the effects of a function/method call on all of 71 /// its arguments. 72 typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 73 74 namespace { 75 class RefVal { 76 public: 77 enum Kind { 78 Owned = 0, // Owning reference. 79 NotOwned, // Reference is not owned by still valid (not freed). 80 Released, // Object has been released. 81 ReturnedOwned, // Returned object passes ownership to caller. 82 ReturnedNotOwned, // Return object does not pass ownership to caller. 83 ERROR_START, 84 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 85 ErrorDeallocGC, // Calling -dealloc with GC enabled. 86 ErrorUseAfterRelease, // Object used after released. 87 ErrorReleaseNotOwned, // Release of an object that was not owned. 88 ERROR_LEAK_START, 89 ErrorLeak, // A memory leak due to excessive reference counts. 90 ErrorLeakReturned, // A memory leak due to the returning method not having 91 // the correct naming conventions. 92 ErrorGCLeakReturned, 93 ErrorOverAutorelease, 94 ErrorReturnedNotOwned 95 }; 96 97 private: 98 /// The number of outstanding retains. 99 unsigned Cnt; 100 /// The number of outstanding autoreleases. 101 unsigned ACnt; 102 /// The (static) type of the object at the time we started tracking it. 103 QualType T; 104 105 /// The current state of the object. 106 /// 107 /// See the RefVal::Kind enum for possible values. 108 unsigned RawKind : 5; 109 110 /// The kind of object being tracked (CF or ObjC), if known. 111 /// 112 /// See the RetEffect::ObjKind enum for possible values. 113 unsigned RawObjectKind : 2; 114 115 /// True if the current state and/or retain count may turn out to not be the 116 /// best possible approximation of the reference counting state. 117 /// 118 /// If true, the checker may decide to throw away ("override") this state 119 /// in favor of something else when it sees the object being used in new ways. 120 /// 121 /// This setting should not be propagated to state derived from this state. 122 /// Once we start deriving new states, it would be inconsistent to override 123 /// them. 124 unsigned IsOverridable : 1; 125 126 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t, 127 bool Overridable = false) 128 : Cnt(cnt), ACnt(acnt), T(t), RawKind(static_cast<unsigned>(k)), 129 RawObjectKind(static_cast<unsigned>(o)), IsOverridable(Overridable) { 130 assert(getKind() == k && "not enough bits for the kind"); 131 assert(getObjKind() == o && "not enough bits for the object kind"); 132 } 133 134 public: 135 Kind getKind() const { return static_cast<Kind>(RawKind); } 136 137 RetEffect::ObjKind getObjKind() const { 138 return static_cast<RetEffect::ObjKind>(RawObjectKind); 139 } 140 141 unsigned getCount() const { return Cnt; } 142 unsigned getAutoreleaseCount() const { return ACnt; } 143 unsigned getCombinedCounts() const { return Cnt + ACnt; } 144 void clearCounts() { 145 Cnt = 0; 146 ACnt = 0; 147 IsOverridable = false; 148 } 149 void setCount(unsigned i) { 150 Cnt = i; 151 IsOverridable = false; 152 } 153 void setAutoreleaseCount(unsigned i) { 154 ACnt = i; 155 IsOverridable = false; 156 } 157 158 QualType getType() const { return T; } 159 160 bool isOverridable() const { return IsOverridable; } 161 162 bool isOwned() const { 163 return getKind() == Owned; 164 } 165 166 bool isNotOwned() const { 167 return getKind() == NotOwned; 168 } 169 170 bool isReturnedOwned() const { 171 return getKind() == ReturnedOwned; 172 } 173 174 bool isReturnedNotOwned() const { 175 return getKind() == ReturnedNotOwned; 176 } 177 178 /// Create a state for an object whose lifetime is the responsibility of the 179 /// current function, at least partially. 180 /// 181 /// Most commonly, this is an owned object with a retain count of +1. 182 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 183 unsigned Count = 1) { 184 return RefVal(Owned, o, Count, 0, t); 185 } 186 187 /// Create a state for an object whose lifetime is not the responsibility of 188 /// the current function. 189 /// 190 /// Most commonly, this is an unowned object with a retain count of +0. 191 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 192 unsigned Count = 0) { 193 return RefVal(NotOwned, o, Count, 0, t); 194 } 195 196 /// Create an "overridable" state for an unowned object at +0. 197 /// 198 /// An overridable state is one that provides a good approximation of the 199 /// reference counting state now, but which may be discarded later if the 200 /// checker sees the object being used in new ways. 201 static RefVal makeOverridableNotOwned(RetEffect::ObjKind o, QualType t) { 202 return RefVal(NotOwned, o, 0, 0, t, /*Overridable=*/true); 203 } 204 205 RefVal operator-(size_t i) const { 206 return RefVal(getKind(), getObjKind(), getCount() - i, 207 getAutoreleaseCount(), getType()); 208 } 209 210 RefVal operator+(size_t i) const { 211 return RefVal(getKind(), getObjKind(), getCount() + i, 212 getAutoreleaseCount(), getType()); 213 } 214 215 RefVal operator^(Kind k) const { 216 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 217 getType()); 218 } 219 220 RefVal autorelease() const { 221 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 222 getType()); 223 } 224 225 // Comparison, profiling, and pretty-printing. 226 227 bool hasSameState(const RefVal &X) const { 228 return getKind() == X.getKind() && Cnt == X.Cnt && ACnt == X.ACnt; 229 } 230 231 bool operator==(const RefVal& X) const { 232 return T == X.T && hasSameState(X) && getObjKind() == X.getObjKind() && 233 IsOverridable == X.IsOverridable; 234 } 235 236 void Profile(llvm::FoldingSetNodeID& ID) const { 237 ID.Add(T); 238 ID.AddInteger(RawKind); 239 ID.AddInteger(Cnt); 240 ID.AddInteger(ACnt); 241 ID.AddInteger(RawObjectKind); 242 ID.AddBoolean(IsOverridable); 243 } 244 245 void print(raw_ostream &Out) const; 246 }; 247 248 void RefVal::print(raw_ostream &Out) const { 249 if (!T.isNull()) 250 Out << "Tracked " << T.getAsString() << '/'; 251 252 if (isOverridable()) 253 Out << "(overridable) "; 254 255 switch (getKind()) { 256 default: llvm_unreachable("Invalid RefVal kind"); 257 case Owned: { 258 Out << "Owned"; 259 unsigned cnt = getCount(); 260 if (cnt) Out << " (+ " << cnt << ")"; 261 break; 262 } 263 264 case NotOwned: { 265 Out << "NotOwned"; 266 unsigned cnt = getCount(); 267 if (cnt) Out << " (+ " << cnt << ")"; 268 break; 269 } 270 271 case ReturnedOwned: { 272 Out << "ReturnedOwned"; 273 unsigned cnt = getCount(); 274 if (cnt) Out << " (+ " << cnt << ")"; 275 break; 276 } 277 278 case ReturnedNotOwned: { 279 Out << "ReturnedNotOwned"; 280 unsigned cnt = getCount(); 281 if (cnt) Out << " (+ " << cnt << ")"; 282 break; 283 } 284 285 case Released: 286 Out << "Released"; 287 break; 288 289 case ErrorDeallocGC: 290 Out << "-dealloc (GC)"; 291 break; 292 293 case ErrorDeallocNotOwned: 294 Out << "-dealloc (not-owned)"; 295 break; 296 297 case ErrorLeak: 298 Out << "Leaked"; 299 break; 300 301 case ErrorLeakReturned: 302 Out << "Leaked (Bad naming)"; 303 break; 304 305 case ErrorGCLeakReturned: 306 Out << "Leaked (GC-ed at return)"; 307 break; 308 309 case ErrorUseAfterRelease: 310 Out << "Use-After-Release [ERROR]"; 311 break; 312 313 case ErrorReleaseNotOwned: 314 Out << "Release of Not-Owned [ERROR]"; 315 break; 316 317 case RefVal::ErrorOverAutorelease: 318 Out << "Over-autoreleased"; 319 break; 320 321 case RefVal::ErrorReturnedNotOwned: 322 Out << "Non-owned object returned instead of owned"; 323 break; 324 } 325 326 if (ACnt) { 327 Out << " [ARC +" << ACnt << ']'; 328 } 329 } 330 } //end anonymous namespace 331 332 //===----------------------------------------------------------------------===// 333 // RefBindings - State used to track object reference counts. 334 //===----------------------------------------------------------------------===// 335 336 REGISTER_MAP_WITH_PROGRAMSTATE(RefBindings, SymbolRef, RefVal) 337 338 static inline const RefVal *getRefBinding(ProgramStateRef State, 339 SymbolRef Sym) { 340 return State->get<RefBindings>(Sym); 341 } 342 343 static inline ProgramStateRef setRefBinding(ProgramStateRef State, 344 SymbolRef Sym, RefVal Val) { 345 return State->set<RefBindings>(Sym, Val); 346 } 347 348 static ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) { 349 return State->remove<RefBindings>(Sym); 350 } 351 352 //===----------------------------------------------------------------------===// 353 // Function/Method behavior summaries. 354 //===----------------------------------------------------------------------===// 355 356 namespace { 357 class RetainSummary { 358 /// Args - a map of (index, ArgEffect) pairs, where index 359 /// specifies the argument (starting from 0). This can be sparsely 360 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 361 ArgEffects Args; 362 363 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 364 /// do not have an entry in Args. 365 ArgEffect DefaultArgEffect; 366 367 /// Receiver - If this summary applies to an Objective-C message expression, 368 /// this is the effect applied to the state of the receiver. 369 ArgEffect Receiver; 370 371 /// Ret - The effect on the return value. Used to indicate if the 372 /// function/method call returns a new tracked symbol. 373 RetEffect Ret; 374 375 public: 376 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 377 ArgEffect ReceiverEff) 378 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 379 380 /// getArg - Return the argument effect on the argument specified by 381 /// idx (starting from 0). 382 ArgEffect getArg(unsigned idx) const { 383 if (const ArgEffect *AE = Args.lookup(idx)) 384 return *AE; 385 386 return DefaultArgEffect; 387 } 388 389 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 390 Args = af.add(Args, idx, e); 391 } 392 393 /// setDefaultArgEffect - Set the default argument effect. 394 void setDefaultArgEffect(ArgEffect E) { 395 DefaultArgEffect = E; 396 } 397 398 /// getRetEffect - Returns the effect on the return value of the call. 399 RetEffect getRetEffect() const { return Ret; } 400 401 /// setRetEffect - Set the effect of the return value of the call. 402 void setRetEffect(RetEffect E) { Ret = E; } 403 404 405 /// Sets the effect on the receiver of the message. 406 void setReceiverEffect(ArgEffect e) { Receiver = e; } 407 408 /// getReceiverEffect - Returns the effect on the receiver of the call. 409 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 410 ArgEffect getReceiverEffect() const { return Receiver; } 411 412 /// Test if two retain summaries are identical. Note that merely equivalent 413 /// summaries are not necessarily identical (for example, if an explicit 414 /// argument effect matches the default effect). 415 bool operator==(const RetainSummary &Other) const { 416 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 417 Receiver == Other.Receiver && Ret == Other.Ret; 418 } 419 420 /// Profile this summary for inclusion in a FoldingSet. 421 void Profile(llvm::FoldingSetNodeID& ID) const { 422 ID.Add(Args); 423 ID.Add(DefaultArgEffect); 424 ID.Add(Receiver); 425 ID.Add(Ret); 426 } 427 428 /// A retain summary is simple if it has no ArgEffects other than the default. 429 bool isSimple() const { 430 return Args.isEmpty(); 431 } 432 433 private: 434 ArgEffects getArgEffects() const { return Args; } 435 ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; } 436 437 friend class RetainSummaryManager; 438 }; 439 } // end anonymous namespace 440 441 //===----------------------------------------------------------------------===// 442 // Data structures for constructing summaries. 443 //===----------------------------------------------------------------------===// 444 445 namespace { 446 class ObjCSummaryKey { 447 IdentifierInfo* II; 448 Selector S; 449 public: 450 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 451 : II(ii), S(s) {} 452 453 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 454 : II(d ? d->getIdentifier() : nullptr), S(s) {} 455 456 ObjCSummaryKey(Selector s) 457 : II(nullptr), S(s) {} 458 459 IdentifierInfo *getIdentifier() const { return II; } 460 Selector getSelector() const { return S; } 461 }; 462 } 463 464 namespace llvm { 465 template <> struct DenseMapInfo<ObjCSummaryKey> { 466 static inline ObjCSummaryKey getEmptyKey() { 467 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 468 DenseMapInfo<Selector>::getEmptyKey()); 469 } 470 471 static inline ObjCSummaryKey getTombstoneKey() { 472 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 473 DenseMapInfo<Selector>::getTombstoneKey()); 474 } 475 476 static unsigned getHashValue(const ObjCSummaryKey &V) { 477 typedef std::pair<IdentifierInfo*, Selector> PairTy; 478 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 479 V.getSelector())); 480 } 481 482 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 483 return LHS.getIdentifier() == RHS.getIdentifier() && 484 LHS.getSelector() == RHS.getSelector(); 485 } 486 487 }; 488 } // end llvm namespace 489 490 namespace { 491 class ObjCSummaryCache { 492 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 493 MapTy M; 494 public: 495 ObjCSummaryCache() {} 496 497 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 498 // Do a lookup with the (D,S) pair. If we find a match return 499 // the iterator. 500 ObjCSummaryKey K(D, S); 501 MapTy::iterator I = M.find(K); 502 503 if (I != M.end()) 504 return I->second; 505 if (!D) 506 return nullptr; 507 508 // Walk the super chain. If we find a hit with a parent, we'll end 509 // up returning that summary. We actually allow that key (null,S), as 510 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 511 // generate initial summaries without having to worry about NSObject 512 // being declared. 513 // FIXME: We may change this at some point. 514 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 515 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 516 break; 517 518 if (!C) 519 return nullptr; 520 } 521 522 // Cache the summary with original key to make the next lookup faster 523 // and return the iterator. 524 const RetainSummary *Summ = I->second; 525 M[K] = Summ; 526 return Summ; 527 } 528 529 const RetainSummary *find(IdentifierInfo* II, Selector S) { 530 // FIXME: Class method lookup. Right now we dont' have a good way 531 // of going between IdentifierInfo* and the class hierarchy. 532 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 533 534 if (I == M.end()) 535 I = M.find(ObjCSummaryKey(S)); 536 537 return I == M.end() ? nullptr : I->second; 538 } 539 540 const RetainSummary *& operator[](ObjCSummaryKey K) { 541 return M[K]; 542 } 543 544 const RetainSummary *& operator[](Selector S) { 545 return M[ ObjCSummaryKey(S) ]; 546 } 547 }; 548 } // end anonymous namespace 549 550 //===----------------------------------------------------------------------===// 551 // Data structures for managing collections of summaries. 552 //===----------------------------------------------------------------------===// 553 554 namespace { 555 class RetainSummaryManager { 556 557 //==-----------------------------------------------------------------==// 558 // Typedefs. 559 //==-----------------------------------------------------------------==// 560 561 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 562 FuncSummariesTy; 563 564 typedef ObjCSummaryCache ObjCMethodSummariesTy; 565 566 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 567 568 //==-----------------------------------------------------------------==// 569 // Data. 570 //==-----------------------------------------------------------------==// 571 572 /// Ctx - The ASTContext object for the analyzed ASTs. 573 ASTContext &Ctx; 574 575 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 576 const bool GCEnabled; 577 578 /// Records whether or not the analyzed code runs in ARC mode. 579 const bool ARCEnabled; 580 581 /// FuncSummaries - A map from FunctionDecls to summaries. 582 FuncSummariesTy FuncSummaries; 583 584 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 585 /// to summaries. 586 ObjCMethodSummariesTy ObjCClassMethodSummaries; 587 588 /// ObjCMethodSummaries - A map from selectors to summaries. 589 ObjCMethodSummariesTy ObjCMethodSummaries; 590 591 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 592 /// and all other data used by the checker. 593 llvm::BumpPtrAllocator BPAlloc; 594 595 /// AF - A factory for ArgEffects objects. 596 ArgEffects::Factory AF; 597 598 /// ScratchArgs - A holding buffer for construct ArgEffects. 599 ArgEffects ScratchArgs; 600 601 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 602 /// objects. 603 RetEffect ObjCAllocRetE; 604 605 /// ObjCInitRetE - Default return effect for init methods returning 606 /// Objective-C objects. 607 RetEffect ObjCInitRetE; 608 609 /// SimpleSummaries - Used for uniquing summaries that don't have special 610 /// effects. 611 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 612 613 //==-----------------------------------------------------------------==// 614 // Methods. 615 //==-----------------------------------------------------------------==// 616 617 /// getArgEffects - Returns a persistent ArgEffects object based on the 618 /// data in ScratchArgs. 619 ArgEffects getArgEffects(); 620 621 enum UnaryFuncKind { cfretain, cfrelease, cfautorelease, cfmakecollectable }; 622 623 const RetainSummary *getUnarySummary(const FunctionType* FT, 624 UnaryFuncKind func); 625 626 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 627 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 628 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 629 630 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 631 632 const RetainSummary *getPersistentSummary(RetEffect RetEff, 633 ArgEffect ReceiverEff = DoNothing, 634 ArgEffect DefaultEff = MayEscape) { 635 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 636 return getPersistentSummary(Summ); 637 } 638 639 const RetainSummary *getDoNothingSummary() { 640 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 641 } 642 643 const RetainSummary *getDefaultSummary() { 644 return getPersistentSummary(RetEffect::MakeNoRet(), 645 DoNothing, MayEscape); 646 } 647 648 const RetainSummary *getPersistentStopSummary() { 649 return getPersistentSummary(RetEffect::MakeNoRet(), 650 StopTracking, StopTracking); 651 } 652 653 void InitializeClassMethodSummaries(); 654 void InitializeMethodSummaries(); 655 private: 656 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 657 ObjCClassMethodSummaries[S] = Summ; 658 } 659 660 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 661 ObjCMethodSummaries[S] = Summ; 662 } 663 664 void addClassMethSummary(const char* Cls, const char* name, 665 const RetainSummary *Summ, bool isNullary = true) { 666 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 667 Selector S = isNullary ? GetNullarySelector(name, Ctx) 668 : GetUnarySelector(name, Ctx); 669 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 670 } 671 672 void addInstMethSummary(const char* Cls, const char* nullaryName, 673 const RetainSummary *Summ) { 674 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 675 Selector S = GetNullarySelector(nullaryName, Ctx); 676 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 677 } 678 679 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy &Summaries, 680 const RetainSummary *Summ, va_list argp) { 681 Selector S = getKeywordSelector(Ctx, argp); 682 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 683 } 684 685 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 686 va_list argp; 687 va_start(argp, Summ); 688 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 689 va_end(argp); 690 } 691 692 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 693 va_list argp; 694 va_start(argp, Summ); 695 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 696 va_end(argp); 697 } 698 699 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 700 va_list argp; 701 va_start(argp, Summ); 702 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 703 va_end(argp); 704 } 705 706 public: 707 708 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 709 : Ctx(ctx), 710 GCEnabled(gcenabled), 711 ARCEnabled(usesARC), 712 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 713 ObjCAllocRetE(gcenabled 714 ? RetEffect::MakeGCNotOwned() 715 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC) 716 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 717 ObjCInitRetE(gcenabled 718 ? RetEffect::MakeGCNotOwned() 719 : (usesARC ? RetEffect::MakeNotOwned(RetEffect::ObjC) 720 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 721 InitializeClassMethodSummaries(); 722 InitializeMethodSummaries(); 723 } 724 725 const RetainSummary *getSummary(const CallEvent &Call, 726 ProgramStateRef State = nullptr); 727 728 const RetainSummary *getFunctionSummary(const FunctionDecl *FD); 729 730 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 731 const ObjCMethodDecl *MD, 732 QualType RetTy, 733 ObjCMethodSummariesTy &CachedSummaries); 734 735 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M, 736 ProgramStateRef State); 737 738 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) { 739 assert(!M.isInstanceMessage()); 740 const ObjCInterfaceDecl *Class = M.getReceiverInterface(); 741 742 return getMethodSummary(M.getSelector(), Class, M.getDecl(), 743 M.getResultType(), ObjCClassMethodSummaries); 744 } 745 746 /// getMethodSummary - This version of getMethodSummary is used to query 747 /// the summary for the current method being analyzed. 748 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 749 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 750 Selector S = MD->getSelector(); 751 QualType ResultTy = MD->getReturnType(); 752 753 ObjCMethodSummariesTy *CachedSummaries; 754 if (MD->isInstanceMethod()) 755 CachedSummaries = &ObjCMethodSummaries; 756 else 757 CachedSummaries = &ObjCClassMethodSummaries; 758 759 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries); 760 } 761 762 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, 763 Selector S, QualType RetTy); 764 765 /// Determine if there is a special return effect for this function or method. 766 Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy, 767 const Decl *D); 768 769 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 770 const ObjCMethodDecl *MD); 771 772 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 773 const FunctionDecl *FD); 774 775 void updateSummaryForCall(const RetainSummary *&Summ, 776 const CallEvent &Call); 777 778 bool isGCEnabled() const { return GCEnabled; } 779 780 bool isARCEnabled() const { return ARCEnabled; } 781 782 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 783 784 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 785 786 friend class RetainSummaryTemplate; 787 }; 788 789 // Used to avoid allocating long-term (BPAlloc'd) memory for default retain 790 // summaries. If a function or method looks like it has a default summary, but 791 // it has annotations, the annotations are added to the stack-based template 792 // and then copied into managed memory. 793 class RetainSummaryTemplate { 794 RetainSummaryManager &Manager; 795 const RetainSummary *&RealSummary; 796 RetainSummary ScratchSummary; 797 bool Accessed; 798 public: 799 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr) 800 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {} 801 802 ~RetainSummaryTemplate() { 803 if (Accessed) 804 RealSummary = Manager.getPersistentSummary(ScratchSummary); 805 } 806 807 RetainSummary &operator*() { 808 Accessed = true; 809 return ScratchSummary; 810 } 811 812 RetainSummary *operator->() { 813 Accessed = true; 814 return &ScratchSummary; 815 } 816 }; 817 818 } // end anonymous namespace 819 820 //===----------------------------------------------------------------------===// 821 // Implementation of checker data structures. 822 //===----------------------------------------------------------------------===// 823 824 ArgEffects RetainSummaryManager::getArgEffects() { 825 ArgEffects AE = ScratchArgs; 826 ScratchArgs = AF.getEmptyMap(); 827 return AE; 828 } 829 830 const RetainSummary * 831 RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 832 // Unique "simple" summaries -- those without ArgEffects. 833 if (OldSumm.isSimple()) { 834 llvm::FoldingSetNodeID ID; 835 OldSumm.Profile(ID); 836 837 void *Pos; 838 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 839 840 if (!N) { 841 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 842 new (N) CachedSummaryNode(OldSumm); 843 SimpleSummaries.InsertNode(N, Pos); 844 } 845 846 return &N->getValue(); 847 } 848 849 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 850 new (Summ) RetainSummary(OldSumm); 851 return Summ; 852 } 853 854 //===----------------------------------------------------------------------===// 855 // Summary creation for functions (largely uses of Core Foundation). 856 //===----------------------------------------------------------------------===// 857 858 static bool isRetain(const FunctionDecl *FD, StringRef FName) { 859 return FName.endswith("Retain"); 860 } 861 862 static bool isRelease(const FunctionDecl *FD, StringRef FName) { 863 return FName.endswith("Release"); 864 } 865 866 static bool isAutorelease(const FunctionDecl *FD, StringRef FName) { 867 return FName.endswith("Autorelease"); 868 } 869 870 static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 871 // FIXME: Remove FunctionDecl parameter. 872 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 873 return FName.find("MakeCollectable") != StringRef::npos; 874 } 875 876 static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) { 877 switch (E) { 878 case DoNothing: 879 case Autorelease: 880 case DecRefBridgedTransferred: 881 case IncRef: 882 case IncRefMsg: 883 case MakeCollectable: 884 case MayEscape: 885 case StopTracking: 886 case StopTrackingHard: 887 return StopTrackingHard; 888 case DecRef: 889 case DecRefAndStopTrackingHard: 890 return DecRefAndStopTrackingHard; 891 case DecRefMsg: 892 case DecRefMsgAndStopTrackingHard: 893 return DecRefMsgAndStopTrackingHard; 894 case Dealloc: 895 return Dealloc; 896 } 897 898 llvm_unreachable("Unknown ArgEffect kind"); 899 } 900 901 void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S, 902 const CallEvent &Call) { 903 if (Call.hasNonZeroCallbackArg()) { 904 ArgEffect RecEffect = 905 getStopTrackingHardEquivalent(S->getReceiverEffect()); 906 ArgEffect DefEffect = 907 getStopTrackingHardEquivalent(S->getDefaultArgEffect()); 908 909 ArgEffects CustomArgEffects = S->getArgEffects(); 910 for (ArgEffects::iterator I = CustomArgEffects.begin(), 911 E = CustomArgEffects.end(); 912 I != E; ++I) { 913 ArgEffect Translated = getStopTrackingHardEquivalent(I->second); 914 if (Translated != DefEffect) 915 ScratchArgs = AF.add(ScratchArgs, I->first, Translated); 916 } 917 918 RetEffect RE = RetEffect::MakeNoRetHard(); 919 920 // Special cases where the callback argument CANNOT free the return value. 921 // This can generally only happen if we know that the callback will only be 922 // called when the return value is already being deallocated. 923 if (const SimpleFunctionCall *FC = dyn_cast<SimpleFunctionCall>(&Call)) { 924 if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) { 925 // When the CGBitmapContext is deallocated, the callback here will free 926 // the associated data buffer. 927 if (Name->isStr("CGBitmapContextCreateWithData")) 928 RE = S->getRetEffect(); 929 } 930 } 931 932 S = getPersistentSummary(RE, RecEffect, DefEffect); 933 } 934 935 // Special case '[super init];' and '[self init];' 936 // 937 // Even though calling '[super init]' without assigning the result to self 938 // and checking if the parent returns 'nil' is a bad pattern, it is common. 939 // Additionally, our Self Init checker already warns about it. To avoid 940 // overwhelming the user with messages from both checkers, we model the case 941 // of '[super init]' in cases when it is not consumed by another expression 942 // as if the call preserves the value of 'self'; essentially, assuming it can 943 // never fail and return 'nil'. 944 // Note, we don't want to just stop tracking the value since we want the 945 // RetainCount checker to report leaks and use-after-free if SelfInit checker 946 // is turned off. 947 if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) { 948 if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) { 949 950 // Check if the message is not consumed, we know it will not be used in 951 // an assignment, ex: "self = [super init]". 952 const Expr *ME = MC->getOriginExpr(); 953 const LocationContext *LCtx = MC->getLocationContext(); 954 ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap(); 955 if (!PM.isConsumedExpr(ME)) { 956 RetainSummaryTemplate ModifiableSummaryTemplate(S, *this); 957 ModifiableSummaryTemplate->setReceiverEffect(DoNothing); 958 ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet()); 959 } 960 } 961 962 } 963 } 964 965 const RetainSummary * 966 RetainSummaryManager::getSummary(const CallEvent &Call, 967 ProgramStateRef State) { 968 const RetainSummary *Summ; 969 switch (Call.getKind()) { 970 case CE_Function: 971 Summ = getFunctionSummary(cast<SimpleFunctionCall>(Call).getDecl()); 972 break; 973 case CE_CXXMember: 974 case CE_CXXMemberOperator: 975 case CE_Block: 976 case CE_CXXConstructor: 977 case CE_CXXDestructor: 978 case CE_CXXAllocator: 979 // FIXME: These calls are currently unsupported. 980 return getPersistentStopSummary(); 981 case CE_ObjCMessage: { 982 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); 983 if (Msg.isInstanceMessage()) 984 Summ = getInstanceMethodSummary(Msg, State); 985 else 986 Summ = getClassMethodSummary(Msg); 987 break; 988 } 989 } 990 991 updateSummaryForCall(Summ, Call); 992 993 assert(Summ && "Unknown call type?"); 994 return Summ; 995 } 996 997 const RetainSummary * 998 RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) { 999 // If we don't know what function we're calling, use our default summary. 1000 if (!FD) 1001 return getDefaultSummary(); 1002 1003 // Look up a summary in our cache of FunctionDecls -> Summaries. 1004 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 1005 if (I != FuncSummaries.end()) 1006 return I->second; 1007 1008 // No summary? Generate one. 1009 const RetainSummary *S = nullptr; 1010 bool AllowAnnotations = true; 1011 1012 do { 1013 // We generate "stop" summaries for implicitly defined functions. 1014 if (FD->isImplicit()) { 1015 S = getPersistentStopSummary(); 1016 break; 1017 } 1018 1019 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 1020 // function's type. 1021 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 1022 const IdentifierInfo *II = FD->getIdentifier(); 1023 if (!II) 1024 break; 1025 1026 StringRef FName = II->getName(); 1027 1028 // Strip away preceding '_'. Doing this here will effect all the checks 1029 // down below. 1030 FName = FName.substr(FName.find_first_not_of('_')); 1031 1032 // Inspect the result type. 1033 QualType RetTy = FT->getReturnType(); 1034 1035 // FIXME: This should all be refactored into a chain of "summary lookup" 1036 // filters. 1037 assert(ScratchArgs.isEmpty()); 1038 1039 if (FName == "pthread_create" || FName == "pthread_setspecific") { 1040 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 1041 // This will be addressed better with IPA. 1042 S = getPersistentStopSummary(); 1043 } else if (FName == "NSMakeCollectable") { 1044 // Handle: id NSMakeCollectable(CFTypeRef) 1045 S = (RetTy->isObjCIdType()) 1046 ? getUnarySummary(FT, cfmakecollectable) 1047 : getPersistentStopSummary(); 1048 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained, 1049 // but we can fully model NSMakeCollectable ourselves. 1050 AllowAnnotations = false; 1051 } else if (FName == "CFPlugInInstanceCreate") { 1052 S = getPersistentSummary(RetEffect::MakeNoRet()); 1053 } else if (FName == "IOBSDNameMatching" || 1054 FName == "IOServiceMatching" || 1055 FName == "IOServiceNameMatching" || 1056 FName == "IORegistryEntrySearchCFProperty" || 1057 FName == "IORegistryEntryIDMatching" || 1058 FName == "IOOpenFirmwarePathMatching") { 1059 // Part of <rdar://problem/6961230>. (IOKit) 1060 // This should be addressed using a API table. 1061 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1062 DoNothing, DoNothing); 1063 } else if (FName == "IOServiceGetMatchingService" || 1064 FName == "IOServiceGetMatchingServices") { 1065 // FIXES: <rdar://problem/6326900> 1066 // This should be addressed using a API table. This strcmp is also 1067 // a little gross, but there is no need to super optimize here. 1068 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 1069 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1070 } else if (FName == "IOServiceAddNotification" || 1071 FName == "IOServiceAddMatchingNotification") { 1072 // Part of <rdar://problem/6961230>. (IOKit) 1073 // This should be addressed using a API table. 1074 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 1075 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1076 } else if (FName == "CVPixelBufferCreateWithBytes") { 1077 // FIXES: <rdar://problem/7283567> 1078 // Eventually this can be improved by recognizing that the pixel 1079 // buffer passed to CVPixelBufferCreateWithBytes is released via 1080 // a callback and doing full IPA to make sure this is done correctly. 1081 // FIXME: This function has an out parameter that returns an 1082 // allocated object. 1083 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 1084 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1085 } else if (FName == "CGBitmapContextCreateWithData") { 1086 // FIXES: <rdar://problem/7358899> 1087 // Eventually this can be improved by recognizing that 'releaseInfo' 1088 // passed to CGBitmapContextCreateWithData is released via 1089 // a callback and doing full IPA to make sure this is done correctly. 1090 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 1091 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1092 DoNothing, DoNothing); 1093 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 1094 // FIXES: <rdar://problem/7283567> 1095 // Eventually this can be improved by recognizing that the pixel 1096 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 1097 // via a callback and doing full IPA to make sure this is done 1098 // correctly. 1099 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 1100 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1101 } else if (FName == "dispatch_set_context" || 1102 FName == "xpc_connection_set_context") { 1103 // <rdar://problem/11059275> - The analyzer currently doesn't have 1104 // a good way to reason about the finalizer function for libdispatch. 1105 // If we pass a context object that is memory managed, stop tracking it. 1106 // <rdar://problem/13783514> - Same problem, but for XPC. 1107 // FIXME: this hack should possibly go away once we can handle 1108 // libdispatch and XPC finalizers. 1109 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1110 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1111 } else if (FName.startswith("NSLog")) { 1112 S = getDoNothingSummary(); 1113 } else if (FName.startswith("NS") && 1114 (FName.find("Insert") != StringRef::npos)) { 1115 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1116 // be deallocated by NSMapRemove. (radar://11152419) 1117 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1118 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1119 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1120 } 1121 1122 // Did we get a summary? 1123 if (S) 1124 break; 1125 1126 if (RetTy->isPointerType()) { 1127 // For CoreFoundation ('CF') types. 1128 if (cocoa::isRefType(RetTy, "CF", FName)) { 1129 if (isRetain(FD, FName)) { 1130 S = getUnarySummary(FT, cfretain); 1131 } else if (isAutorelease(FD, FName)) { 1132 S = getUnarySummary(FT, cfautorelease); 1133 // The headers use cf_consumed, but we can fully model CFAutorelease 1134 // ourselves. 1135 AllowAnnotations = false; 1136 } else if (isMakeCollectable(FD, FName)) { 1137 S = getUnarySummary(FT, cfmakecollectable); 1138 AllowAnnotations = false; 1139 } else { 1140 S = getCFCreateGetRuleSummary(FD); 1141 } 1142 1143 break; 1144 } 1145 1146 // For CoreGraphics ('CG') types. 1147 if (cocoa::isRefType(RetTy, "CG", FName)) { 1148 if (isRetain(FD, FName)) 1149 S = getUnarySummary(FT, cfretain); 1150 else 1151 S = getCFCreateGetRuleSummary(FD); 1152 1153 break; 1154 } 1155 1156 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1157 if (cocoa::isRefType(RetTy, "DADisk") || 1158 cocoa::isRefType(RetTy, "DADissenter") || 1159 cocoa::isRefType(RetTy, "DASessionRef")) { 1160 S = getCFCreateGetRuleSummary(FD); 1161 break; 1162 } 1163 1164 if (FD->hasAttr<CFAuditedTransferAttr>()) { 1165 S = getCFCreateGetRuleSummary(FD); 1166 break; 1167 } 1168 1169 break; 1170 } 1171 1172 // Check for release functions, the only kind of functions that we care 1173 // about that don't return a pointer type. 1174 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1175 // Test for 'CGCF'. 1176 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1177 1178 if (isRelease(FD, FName)) 1179 S = getUnarySummary(FT, cfrelease); 1180 else { 1181 assert (ScratchArgs.isEmpty()); 1182 // Remaining CoreFoundation and CoreGraphics functions. 1183 // We use to assume that they all strictly followed the ownership idiom 1184 // and that ownership cannot be transferred. While this is technically 1185 // correct, many methods allow a tracked object to escape. For example: 1186 // 1187 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1188 // CFDictionaryAddValue(y, key, x); 1189 // CFRelease(x); 1190 // ... it is okay to use 'x' since 'y' has a reference to it 1191 // 1192 // We handle this and similar cases with the follow heuristic. If the 1193 // function name contains "InsertValue", "SetValue", "AddValue", 1194 // "AppendValue", or "SetAttribute", then we assume that arguments may 1195 // "escape." This means that something else holds on to the object, 1196 // allowing it be used even after its local retain count drops to 0. 1197 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1198 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1199 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1200 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1201 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1202 ? MayEscape : DoNothing; 1203 1204 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1205 } 1206 } 1207 } 1208 while (0); 1209 1210 // If we got all the way here without any luck, use a default summary. 1211 if (!S) 1212 S = getDefaultSummary(); 1213 1214 // Annotations override defaults. 1215 if (AllowAnnotations) 1216 updateSummaryFromAnnotations(S, FD); 1217 1218 FuncSummaries[FD] = S; 1219 return S; 1220 } 1221 1222 const RetainSummary * 1223 RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1224 if (coreFoundation::followsCreateRule(FD)) 1225 return getCFSummaryCreateRule(FD); 1226 1227 return getCFSummaryGetRule(FD); 1228 } 1229 1230 const RetainSummary * 1231 RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1232 UnaryFuncKind func) { 1233 1234 // Sanity check that this is *really* a unary function. This can 1235 // happen if people do weird things. 1236 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1237 if (!FTP || FTP->getNumParams() != 1) 1238 return getPersistentStopSummary(); 1239 1240 assert (ScratchArgs.isEmpty()); 1241 1242 ArgEffect Effect; 1243 switch (func) { 1244 case cfretain: Effect = IncRef; break; 1245 case cfrelease: Effect = DecRef; break; 1246 case cfautorelease: Effect = Autorelease; break; 1247 case cfmakecollectable: Effect = MakeCollectable; break; 1248 } 1249 1250 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1251 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1252 } 1253 1254 const RetainSummary * 1255 RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1256 assert (ScratchArgs.isEmpty()); 1257 1258 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1259 } 1260 1261 const RetainSummary * 1262 RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1263 assert (ScratchArgs.isEmpty()); 1264 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1265 DoNothing, DoNothing); 1266 } 1267 1268 //===----------------------------------------------------------------------===// 1269 // Summary creation for Selectors. 1270 //===----------------------------------------------------------------------===// 1271 1272 Optional<RetEffect> 1273 RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy, 1274 const Decl *D) { 1275 if (cocoa::isCocoaObjectRef(RetTy)) { 1276 if (D->hasAttr<NSReturnsRetainedAttr>()) 1277 return ObjCAllocRetE; 1278 1279 if (D->hasAttr<NSReturnsNotRetainedAttr>() || 1280 D->hasAttr<NSReturnsAutoreleasedAttr>()) 1281 return RetEffect::MakeNotOwned(RetEffect::ObjC); 1282 1283 } else if (!RetTy->isPointerType()) { 1284 return None; 1285 } 1286 1287 if (D->hasAttr<CFReturnsRetainedAttr>()) 1288 return RetEffect::MakeOwned(RetEffect::CF, true); 1289 1290 if (D->hasAttr<CFReturnsNotRetainedAttr>()) 1291 return RetEffect::MakeNotOwned(RetEffect::CF); 1292 1293 return None; 1294 } 1295 1296 void 1297 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1298 const FunctionDecl *FD) { 1299 if (!FD) 1300 return; 1301 1302 assert(Summ && "Must have a summary to add annotations to."); 1303 RetainSummaryTemplate Template(Summ, *this); 1304 1305 // Effects on the parameters. 1306 unsigned parm_idx = 0; 1307 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1308 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1309 const ParmVarDecl *pd = *pi; 1310 if (pd->hasAttr<NSConsumedAttr>()) 1311 Template->addArg(AF, parm_idx, DecRefMsg); 1312 else if (pd->hasAttr<CFConsumedAttr>()) 1313 Template->addArg(AF, parm_idx, DecRef); 1314 } 1315 1316 QualType RetTy = FD->getReturnType(); 1317 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD)) 1318 Template->setRetEffect(*RetE); 1319 } 1320 1321 void 1322 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1323 const ObjCMethodDecl *MD) { 1324 if (!MD) 1325 return; 1326 1327 assert(Summ && "Must have a valid summary to add annotations to"); 1328 RetainSummaryTemplate Template(Summ, *this); 1329 1330 // Effects on the receiver. 1331 if (MD->hasAttr<NSConsumesSelfAttr>()) 1332 Template->setReceiverEffect(DecRefMsg); 1333 1334 // Effects on the parameters. 1335 unsigned parm_idx = 0; 1336 for (ObjCMethodDecl::param_const_iterator 1337 pi=MD->param_begin(), pe=MD->param_end(); 1338 pi != pe; ++pi, ++parm_idx) { 1339 const ParmVarDecl *pd = *pi; 1340 if (pd->hasAttr<NSConsumedAttr>()) 1341 Template->addArg(AF, parm_idx, DecRefMsg); 1342 else if (pd->hasAttr<CFConsumedAttr>()) { 1343 Template->addArg(AF, parm_idx, DecRef); 1344 } 1345 } 1346 1347 QualType RetTy = MD->getReturnType(); 1348 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD)) 1349 Template->setRetEffect(*RetE); 1350 } 1351 1352 const RetainSummary * 1353 RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1354 Selector S, QualType RetTy) { 1355 // Any special effects? 1356 ArgEffect ReceiverEff = DoNothing; 1357 RetEffect ResultEff = RetEffect::MakeNoRet(); 1358 1359 // Check the method family, and apply any default annotations. 1360 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1361 case OMF_None: 1362 case OMF_performSelector: 1363 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1364 // FIXME: Does the non-threaded performSelector family really belong here? 1365 // The selector could be, say, @selector(copy). 1366 if (cocoa::isCocoaObjectRef(RetTy)) 1367 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1368 else if (coreFoundation::isCFObjectRef(RetTy)) { 1369 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1370 // values for alloc, new, copy, or mutableCopy, so we have to 1371 // double-check with the selector. This is ugly, but there aren't that 1372 // many Objective-C methods that return CF objects, right? 1373 if (MD) { 1374 switch (S.getMethodFamily()) { 1375 case OMF_alloc: 1376 case OMF_new: 1377 case OMF_copy: 1378 case OMF_mutableCopy: 1379 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1380 break; 1381 default: 1382 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1383 break; 1384 } 1385 } else { 1386 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1387 } 1388 } 1389 break; 1390 case OMF_init: 1391 ResultEff = ObjCInitRetE; 1392 ReceiverEff = DecRefMsg; 1393 break; 1394 case OMF_alloc: 1395 case OMF_new: 1396 case OMF_copy: 1397 case OMF_mutableCopy: 1398 if (cocoa::isCocoaObjectRef(RetTy)) 1399 ResultEff = ObjCAllocRetE; 1400 else if (coreFoundation::isCFObjectRef(RetTy)) 1401 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1402 break; 1403 case OMF_autorelease: 1404 ReceiverEff = Autorelease; 1405 break; 1406 case OMF_retain: 1407 ReceiverEff = IncRefMsg; 1408 break; 1409 case OMF_release: 1410 ReceiverEff = DecRefMsg; 1411 break; 1412 case OMF_dealloc: 1413 ReceiverEff = Dealloc; 1414 break; 1415 case OMF_self: 1416 // -self is handled specially by the ExprEngine to propagate the receiver. 1417 break; 1418 case OMF_retainCount: 1419 case OMF_finalize: 1420 // These methods don't return objects. 1421 break; 1422 } 1423 1424 // If one of the arguments in the selector has the keyword 'delegate' we 1425 // should stop tracking the reference count for the receiver. This is 1426 // because the reference count is quite possibly handled by a delegate 1427 // method. 1428 if (S.isKeywordSelector()) { 1429 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { 1430 StringRef Slot = S.getNameForSlot(i); 1431 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { 1432 if (ResultEff == ObjCInitRetE) 1433 ResultEff = RetEffect::MakeNoRetHard(); 1434 else 1435 ReceiverEff = StopTrackingHard; 1436 } 1437 } 1438 } 1439 1440 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1441 ResultEff.getKind() == RetEffect::NoRet) 1442 return getDefaultSummary(); 1443 1444 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1445 } 1446 1447 const RetainSummary * 1448 RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg, 1449 ProgramStateRef State) { 1450 const ObjCInterfaceDecl *ReceiverClass = nullptr; 1451 1452 // We do better tracking of the type of the object than the core ExprEngine. 1453 // See if we have its type in our private state. 1454 // FIXME: Eventually replace the use of state->get<RefBindings> with 1455 // a generic API for reasoning about the Objective-C types of symbolic 1456 // objects. 1457 SVal ReceiverV = Msg.getReceiverSVal(); 1458 if (SymbolRef Sym = ReceiverV.getAsLocSymbol()) 1459 if (const RefVal *T = getRefBinding(State, Sym)) 1460 if (const ObjCObjectPointerType *PT = 1461 T->getType()->getAs<ObjCObjectPointerType>()) 1462 ReceiverClass = PT->getInterfaceDecl(); 1463 1464 // If we don't know what kind of object this is, fall back to its static type. 1465 if (!ReceiverClass) 1466 ReceiverClass = Msg.getReceiverInterface(); 1467 1468 // FIXME: The receiver could be a reference to a class, meaning that 1469 // we should use the class method. 1470 // id x = [NSObject class]; 1471 // [x performSelector:... withObject:... afterDelay:...]; 1472 Selector S = Msg.getSelector(); 1473 const ObjCMethodDecl *Method = Msg.getDecl(); 1474 if (!Method && ReceiverClass) 1475 Method = ReceiverClass->getInstanceMethod(S); 1476 1477 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(), 1478 ObjCMethodSummaries); 1479 } 1480 1481 const RetainSummary * 1482 RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 1483 const ObjCMethodDecl *MD, QualType RetTy, 1484 ObjCMethodSummariesTy &CachedSummaries) { 1485 1486 // Look up a summary in our summary cache. 1487 const RetainSummary *Summ = CachedSummaries.find(ID, S); 1488 1489 if (!Summ) { 1490 Summ = getStandardMethodSummary(MD, S, RetTy); 1491 1492 // Annotations override defaults. 1493 updateSummaryFromAnnotations(Summ, MD); 1494 1495 // Memoize the summary. 1496 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ; 1497 } 1498 1499 return Summ; 1500 } 1501 1502 void RetainSummaryManager::InitializeClassMethodSummaries() { 1503 assert(ScratchArgs.isEmpty()); 1504 // Create the [NSAssertionHandler currentHander] summary. 1505 addClassMethSummary("NSAssertionHandler", "currentHandler", 1506 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1507 1508 // Create the [NSAutoreleasePool addObject:] summary. 1509 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1510 addClassMethSummary("NSAutoreleasePool", "addObject", 1511 getPersistentSummary(RetEffect::MakeNoRet(), 1512 DoNothing, Autorelease)); 1513 } 1514 1515 void RetainSummaryManager::InitializeMethodSummaries() { 1516 1517 assert (ScratchArgs.isEmpty()); 1518 1519 // Create the "init" selector. It just acts as a pass-through for the 1520 // receiver. 1521 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1522 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1523 1524 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1525 // claims the receiver and returns a retained object. 1526 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1527 InitSumm); 1528 1529 // The next methods are allocators. 1530 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1531 const RetainSummary *CFAllocSumm = 1532 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1533 1534 // Create the "retain" selector. 1535 RetEffect NoRet = RetEffect::MakeNoRet(); 1536 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1537 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1538 1539 // Create the "release" selector. 1540 Summ = getPersistentSummary(NoRet, DecRefMsg); 1541 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1542 1543 // Create the -dealloc summary. 1544 Summ = getPersistentSummary(NoRet, Dealloc); 1545 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1546 1547 // Create the "autorelease" selector. 1548 Summ = getPersistentSummary(NoRet, Autorelease); 1549 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1550 1551 // For NSWindow, allocated objects are (initially) self-owned. 1552 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1553 // self-own themselves. However, they only do this once they are displayed. 1554 // Thus, we need to track an NSWindow's display status. 1555 // This is tracked in <rdar://problem/6062711>. 1556 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1557 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1558 StopTracking, 1559 StopTracking); 1560 1561 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1562 1563 // For NSPanel (which subclasses NSWindow), allocated objects are not 1564 // self-owned. 1565 // FIXME: For now we don't track NSPanels. object for the same reason 1566 // as for NSWindow objects. 1567 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1568 1569 // For NSNull, objects returned by +null are singletons that ignore 1570 // retain/release semantics. Just don't track them. 1571 // <rdar://problem/12858915> 1572 addClassMethSummary("NSNull", "null", NoTrackYet); 1573 1574 // Don't track allocated autorelease pools, as it is okay to prematurely 1575 // exit a method. 1576 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1577 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1578 addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet); 1579 1580 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1581 addInstMethSummary("QCRenderer", AllocSumm, 1582 "createSnapshotImageOfType", NULL); 1583 addInstMethSummary("QCView", AllocSumm, 1584 "createSnapshotImageOfType", NULL); 1585 1586 // Create summaries for CIContext, 'createCGImage' and 1587 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1588 // automatically garbage collected. 1589 addInstMethSummary("CIContext", CFAllocSumm, 1590 "createCGImage", "fromRect", NULL); 1591 addInstMethSummary("CIContext", CFAllocSumm, 1592 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1593 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1594 "info", NULL); 1595 } 1596 1597 //===----------------------------------------------------------------------===// 1598 // Error reporting. 1599 //===----------------------------------------------------------------------===// 1600 namespace { 1601 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1602 SummaryLogTy; 1603 1604 //===-------------===// 1605 // Bug Descriptions. // 1606 //===-------------===// 1607 1608 class CFRefBug : public BugType { 1609 protected: 1610 CFRefBug(const CheckerBase *checker, StringRef name) 1611 : BugType(checker, name, categories::MemoryCoreFoundationObjectiveC) {} 1612 1613 public: 1614 1615 // FIXME: Eventually remove. 1616 virtual const char *getDescription() const = 0; 1617 1618 virtual bool isLeak() const { return false; } 1619 }; 1620 1621 class UseAfterRelease : public CFRefBug { 1622 public: 1623 UseAfterRelease(const CheckerBase *checker) 1624 : CFRefBug(checker, "Use-after-release") {} 1625 1626 const char *getDescription() const override { 1627 return "Reference-counted object is used after it is released"; 1628 } 1629 }; 1630 1631 class BadRelease : public CFRefBug { 1632 public: 1633 BadRelease(const CheckerBase *checker) : CFRefBug(checker, "Bad release") {} 1634 1635 const char *getDescription() const override { 1636 return "Incorrect decrement of the reference count of an object that is " 1637 "not owned at this point by the caller"; 1638 } 1639 }; 1640 1641 class DeallocGC : public CFRefBug { 1642 public: 1643 DeallocGC(const CheckerBase *checker) 1644 : CFRefBug(checker, "-dealloc called while using garbage collection") {} 1645 1646 const char *getDescription() const override { 1647 return "-dealloc called while using garbage collection"; 1648 } 1649 }; 1650 1651 class DeallocNotOwned : public CFRefBug { 1652 public: 1653 DeallocNotOwned(const CheckerBase *checker) 1654 : CFRefBug(checker, "-dealloc sent to non-exclusively owned object") {} 1655 1656 const char *getDescription() const override { 1657 return "-dealloc sent to object that may be referenced elsewhere"; 1658 } 1659 }; 1660 1661 class OverAutorelease : public CFRefBug { 1662 public: 1663 OverAutorelease(const CheckerBase *checker) 1664 : CFRefBug(checker, "Object autoreleased too many times") {} 1665 1666 const char *getDescription() const override { 1667 return "Object autoreleased too many times"; 1668 } 1669 }; 1670 1671 class ReturnedNotOwnedForOwned : public CFRefBug { 1672 public: 1673 ReturnedNotOwnedForOwned(const CheckerBase *checker) 1674 : CFRefBug(checker, "Method should return an owned object") {} 1675 1676 const char *getDescription() const override { 1677 return "Object with a +0 retain count returned to caller where a +1 " 1678 "(owning) retain count is expected"; 1679 } 1680 }; 1681 1682 class Leak : public CFRefBug { 1683 public: 1684 Leak(const CheckerBase *checker, StringRef name) : CFRefBug(checker, name) { 1685 // Leaks should not be reported if they are post-dominated by a sink. 1686 setSuppressOnSink(true); 1687 } 1688 1689 const char *getDescription() const override { return ""; } 1690 1691 bool isLeak() const override { return true; } 1692 }; 1693 1694 //===---------===// 1695 // Bug Reports. // 1696 //===---------===// 1697 1698 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1699 protected: 1700 SymbolRef Sym; 1701 const SummaryLogTy &SummaryLog; 1702 bool GCEnabled; 1703 1704 public: 1705 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1706 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1707 1708 void Profile(llvm::FoldingSetNodeID &ID) const override { 1709 static int x = 0; 1710 ID.AddPointer(&x); 1711 ID.AddPointer(Sym); 1712 } 1713 1714 PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1715 const ExplodedNode *PrevN, 1716 BugReporterContext &BRC, 1717 BugReport &BR) override; 1718 1719 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1720 const ExplodedNode *N, 1721 BugReport &BR) override; 1722 }; 1723 1724 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1725 public: 1726 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1727 const SummaryLogTy &log) 1728 : CFRefReportVisitor(sym, GCEnabled, log) {} 1729 1730 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1731 const ExplodedNode *N, 1732 BugReport &BR) override; 1733 1734 BugReporterVisitor *clone() const override { 1735 // The curiously-recurring template pattern only works for one level of 1736 // subclassing. Rather than make a new template base for 1737 // CFRefReportVisitor, we simply override clone() to do the right thing. 1738 // This could be trouble someday if BugReporterVisitorImpl is ever 1739 // used for something else besides a convenient implementation of clone(). 1740 return new CFRefLeakReportVisitor(*this); 1741 } 1742 }; 1743 1744 class CFRefReport : public BugReport { 1745 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1746 1747 public: 1748 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1749 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1750 bool registerVisitor = true) 1751 : BugReport(D, D.getDescription(), n) { 1752 if (registerVisitor) 1753 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1754 addGCModeDescription(LOpts, GCEnabled); 1755 } 1756 1757 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1758 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1759 StringRef endText) 1760 : BugReport(D, D.getDescription(), endText, n) { 1761 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1762 addGCModeDescription(LOpts, GCEnabled); 1763 } 1764 1765 std::pair<ranges_iterator, ranges_iterator> getRanges() override { 1766 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1767 if (!BugTy.isLeak()) 1768 return BugReport::getRanges(); 1769 else 1770 return std::make_pair(ranges_iterator(), ranges_iterator()); 1771 } 1772 }; 1773 1774 class CFRefLeakReport : public CFRefReport { 1775 const MemRegion* AllocBinding; 1776 public: 1777 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1778 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1779 CheckerContext &Ctx, 1780 bool IncludeAllocationLine); 1781 1782 PathDiagnosticLocation getLocation(const SourceManager &SM) const override { 1783 assert(Location.isValid()); 1784 return Location; 1785 } 1786 }; 1787 } // end anonymous namespace 1788 1789 void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1790 bool GCEnabled) { 1791 const char *GCModeDescription = nullptr; 1792 1793 switch (LOpts.getGC()) { 1794 case LangOptions::GCOnly: 1795 assert(GCEnabled); 1796 GCModeDescription = "Code is compiled to only use garbage collection"; 1797 break; 1798 1799 case LangOptions::NonGC: 1800 assert(!GCEnabled); 1801 GCModeDescription = "Code is compiled to use reference counts"; 1802 break; 1803 1804 case LangOptions::HybridGC: 1805 if (GCEnabled) { 1806 GCModeDescription = "Code is compiled to use either garbage collection " 1807 "(GC) or reference counts (non-GC). The bug occurs " 1808 "with GC enabled"; 1809 break; 1810 } else { 1811 GCModeDescription = "Code is compiled to use either garbage collection " 1812 "(GC) or reference counts (non-GC). The bug occurs " 1813 "in non-GC mode"; 1814 break; 1815 } 1816 } 1817 1818 assert(GCModeDescription && "invalid/unknown GC mode"); 1819 addExtraText(GCModeDescription); 1820 } 1821 1822 static bool isNumericLiteralExpression(const Expr *E) { 1823 // FIXME: This set of cases was copied from SemaExprObjC. 1824 return isa<IntegerLiteral>(E) || 1825 isa<CharacterLiteral>(E) || 1826 isa<FloatingLiteral>(E) || 1827 isa<ObjCBoolLiteralExpr>(E) || 1828 isa<CXXBoolLiteralExpr>(E); 1829 } 1830 1831 PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1832 const ExplodedNode *PrevN, 1833 BugReporterContext &BRC, 1834 BugReport &BR) { 1835 // FIXME: We will eventually need to handle non-statement-based events 1836 // (__attribute__((cleanup))). 1837 if (!N->getLocation().getAs<StmtPoint>()) 1838 return nullptr; 1839 1840 // Check if the type state has changed. 1841 ProgramStateRef PrevSt = PrevN->getState(); 1842 ProgramStateRef CurrSt = N->getState(); 1843 const LocationContext *LCtx = N->getLocationContext(); 1844 1845 const RefVal* CurrT = getRefBinding(CurrSt, Sym); 1846 if (!CurrT) return nullptr; 1847 1848 const RefVal &CurrV = *CurrT; 1849 const RefVal *PrevT = getRefBinding(PrevSt, Sym); 1850 1851 // Create a string buffer to constain all the useful things we want 1852 // to tell the user. 1853 std::string sbuf; 1854 llvm::raw_string_ostream os(sbuf); 1855 1856 // This is the allocation site since the previous node had no bindings 1857 // for this symbol. 1858 if (!PrevT) { 1859 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 1860 1861 if (isa<ObjCArrayLiteral>(S)) { 1862 os << "NSArray literal is an object with a +0 retain count"; 1863 } 1864 else if (isa<ObjCDictionaryLiteral>(S)) { 1865 os << "NSDictionary literal is an object with a +0 retain count"; 1866 } 1867 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1868 if (isNumericLiteralExpression(BL->getSubExpr())) 1869 os << "NSNumber literal is an object with a +0 retain count"; 1870 else { 1871 const ObjCInterfaceDecl *BoxClass = nullptr; 1872 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1873 BoxClass = Method->getClassInterface(); 1874 1875 // We should always be able to find the boxing class interface, 1876 // but consider this future-proofing. 1877 if (BoxClass) 1878 os << *BoxClass << " b"; 1879 else 1880 os << "B"; 1881 1882 os << "oxed expression produces an object with a +0 retain count"; 1883 } 1884 } 1885 else { 1886 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1887 // Get the name of the callee (if it is available). 1888 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1889 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1890 os << "Call to function '" << *FD << '\''; 1891 else 1892 os << "function call"; 1893 } 1894 else { 1895 assert(isa<ObjCMessageExpr>(S)); 1896 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager(); 1897 CallEventRef<ObjCMethodCall> Call 1898 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx); 1899 1900 switch (Call->getMessageKind()) { 1901 case OCM_Message: 1902 os << "Method"; 1903 break; 1904 case OCM_PropertyAccess: 1905 os << "Property"; 1906 break; 1907 case OCM_Subscript: 1908 os << "Subscript"; 1909 break; 1910 } 1911 } 1912 1913 if (CurrV.getObjKind() == RetEffect::CF) { 1914 os << " returns a Core Foundation object with a "; 1915 } 1916 else { 1917 assert (CurrV.getObjKind() == RetEffect::ObjC); 1918 os << " returns an Objective-C object with a "; 1919 } 1920 1921 if (CurrV.isOwned()) { 1922 os << "+1 retain count"; 1923 1924 if (GCEnabled) { 1925 assert(CurrV.getObjKind() == RetEffect::CF); 1926 os << ". " 1927 "Core Foundation objects are not automatically garbage collected."; 1928 } 1929 } 1930 else { 1931 assert (CurrV.isNotOwned()); 1932 os << "+0 retain count"; 1933 } 1934 } 1935 1936 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1937 N->getLocationContext()); 1938 return new PathDiagnosticEventPiece(Pos, os.str()); 1939 } 1940 1941 // Gather up the effects that were performed on the object at this 1942 // program point 1943 SmallVector<ArgEffect, 2> AEffects; 1944 1945 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1946 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1947 // We only have summaries attached to nodes after evaluating CallExpr and 1948 // ObjCMessageExprs. 1949 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 1950 1951 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1952 // Iterate through the parameter expressions and see if the symbol 1953 // was ever passed as an argument. 1954 unsigned i = 0; 1955 1956 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1957 AI!=AE; ++AI, ++i) { 1958 1959 // Retrieve the value of the argument. Is it the symbol 1960 // we are interested in? 1961 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1962 continue; 1963 1964 // We have an argument. Get the effect! 1965 AEffects.push_back(Summ->getArg(i)); 1966 } 1967 } 1968 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1969 if (const Expr *receiver = ME->getInstanceReceiver()) 1970 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 1971 .getAsLocSymbol() == Sym) { 1972 // The symbol we are tracking is the receiver. 1973 AEffects.push_back(Summ->getReceiverEffect()); 1974 } 1975 } 1976 } 1977 1978 do { 1979 // Get the previous type state. 1980 RefVal PrevV = *PrevT; 1981 1982 // Specially handle -dealloc. 1983 if (!GCEnabled && std::find(AEffects.begin(), AEffects.end(), Dealloc) != 1984 AEffects.end()) { 1985 // Determine if the object's reference count was pushed to zero. 1986 assert(!PrevV.hasSameState(CurrV) && "The state should have changed."); 1987 // We may not have transitioned to 'release' if we hit an error. 1988 // This case is handled elsewhere. 1989 if (CurrV.getKind() == RefVal::Released) { 1990 assert(CurrV.getCombinedCounts() == 0); 1991 os << "Object released by directly sending the '-dealloc' message"; 1992 break; 1993 } 1994 } 1995 1996 // Specially handle CFMakeCollectable and friends. 1997 if (std::find(AEffects.begin(), AEffects.end(), MakeCollectable) != 1998 AEffects.end()) { 1999 // Get the name of the function. 2000 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 2001 SVal X = 2002 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2003 const FunctionDecl *FD = X.getAsFunctionDecl(); 2004 2005 if (GCEnabled) { 2006 // Determine if the object's reference count was pushed to zero. 2007 assert(!PrevV.hasSameState(CurrV) && "The state should have changed."); 2008 2009 os << "In GC mode a call to '" << *FD 2010 << "' decrements an object's retain count and registers the " 2011 "object with the garbage collector. "; 2012 2013 if (CurrV.getKind() == RefVal::Released) { 2014 assert(CurrV.getCount() == 0); 2015 os << "Since it now has a 0 retain count the object can be " 2016 "automatically collected by the garbage collector."; 2017 } 2018 else 2019 os << "An object must have a 0 retain count to be garbage collected. " 2020 "After this call its retain count is +" << CurrV.getCount() 2021 << '.'; 2022 } 2023 else 2024 os << "When GC is not enabled a call to '" << *FD 2025 << "' has no effect on its argument."; 2026 2027 // Nothing more to say. 2028 break; 2029 } 2030 2031 // Determine if the typestate has changed. 2032 if (!PrevV.hasSameState(CurrV)) 2033 switch (CurrV.getKind()) { 2034 case RefVal::Owned: 2035 case RefVal::NotOwned: 2036 2037 if (PrevV.getCount() == CurrV.getCount()) { 2038 // Did an autorelease message get sent? 2039 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2040 return nullptr; 2041 2042 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2043 os << "Object autoreleased"; 2044 break; 2045 } 2046 2047 if (PrevV.getCount() > CurrV.getCount()) 2048 os << "Reference count decremented."; 2049 else 2050 os << "Reference count incremented."; 2051 2052 if (unsigned Count = CurrV.getCount()) 2053 os << " The object now has a +" << Count << " retain count."; 2054 2055 if (PrevV.getKind() == RefVal::Released) { 2056 assert(GCEnabled && CurrV.getCount() > 0); 2057 os << " The object is not eligible for garbage collection until " 2058 "the retain count reaches 0 again."; 2059 } 2060 2061 break; 2062 2063 case RefVal::Released: 2064 os << "Object released."; 2065 break; 2066 2067 case RefVal::ReturnedOwned: 2068 // Autoreleases can be applied after marking a node ReturnedOwned. 2069 if (CurrV.getAutoreleaseCount()) 2070 return nullptr; 2071 2072 os << "Object returned to caller as an owning reference (single " 2073 "retain count transferred to caller)"; 2074 break; 2075 2076 case RefVal::ReturnedNotOwned: 2077 os << "Object returned to caller with a +0 retain count"; 2078 break; 2079 2080 default: 2081 return nullptr; 2082 } 2083 2084 // Emit any remaining diagnostics for the argument effects (if any). 2085 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2086 E=AEffects.end(); I != E; ++I) { 2087 2088 // A bunch of things have alternate behavior under GC. 2089 if (GCEnabled) 2090 switch (*I) { 2091 default: break; 2092 case Autorelease: 2093 os << "In GC mode an 'autorelease' has no effect."; 2094 continue; 2095 case IncRefMsg: 2096 os << "In GC mode the 'retain' message has no effect."; 2097 continue; 2098 case DecRefMsg: 2099 os << "In GC mode the 'release' message has no effect."; 2100 continue; 2101 } 2102 } 2103 } while (0); 2104 2105 if (os.str().empty()) 2106 return nullptr; // We have nothing to say! 2107 2108 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 2109 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2110 N->getLocationContext()); 2111 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2112 2113 // Add the range by scanning the children of the statement for any bindings 2114 // to Sym. 2115 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2116 I!=E; ++I) 2117 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2118 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2119 P->addRange(Exp->getSourceRange()); 2120 break; 2121 } 2122 2123 return P; 2124 } 2125 2126 // Find the first node in the current function context that referred to the 2127 // tracked symbol and the memory location that value was stored to. Note, the 2128 // value is only reported if the allocation occurred in the same function as 2129 // the leak. The function can also return a location context, which should be 2130 // treated as interesting. 2131 struct AllocationInfo { 2132 const ExplodedNode* N; 2133 const MemRegion *R; 2134 const LocationContext *InterestingMethodContext; 2135 AllocationInfo(const ExplodedNode *InN, 2136 const MemRegion *InR, 2137 const LocationContext *InInterestingMethodContext) : 2138 N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {} 2139 }; 2140 2141 static AllocationInfo 2142 GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2143 SymbolRef Sym) { 2144 const ExplodedNode *AllocationNode = N; 2145 const ExplodedNode *AllocationNodeInCurrentContext = N; 2146 const MemRegion *FirstBinding = nullptr; 2147 const LocationContext *LeakContext = N->getLocationContext(); 2148 2149 // The location context of the init method called on the leaked object, if 2150 // available. 2151 const LocationContext *InitMethodContext = nullptr; 2152 2153 while (N) { 2154 ProgramStateRef St = N->getState(); 2155 const LocationContext *NContext = N->getLocationContext(); 2156 2157 if (!getRefBinding(St, Sym)) 2158 break; 2159 2160 StoreManager::FindUniqueBinding FB(Sym); 2161 StateMgr.iterBindings(St, FB); 2162 2163 if (FB) { 2164 const MemRegion *R = FB.getRegion(); 2165 const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>(); 2166 // Do not show local variables belonging to a function other than 2167 // where the error is reported. 2168 if (!VR || VR->getStackFrame() == LeakContext->getCurrentStackFrame()) 2169 FirstBinding = R; 2170 } 2171 2172 // AllocationNode is the last node in which the symbol was tracked. 2173 AllocationNode = N; 2174 2175 // AllocationNodeInCurrentContext, is the last node in the current context 2176 // in which the symbol was tracked. 2177 if (NContext == LeakContext) 2178 AllocationNodeInCurrentContext = N; 2179 2180 // Find the last init that was called on the given symbol and store the 2181 // init method's location context. 2182 if (!InitMethodContext) 2183 if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) { 2184 const Stmt *CE = CEP->getCallExpr(); 2185 if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) { 2186 const Stmt *RecExpr = ME->getInstanceReceiver(); 2187 if (RecExpr) { 2188 SVal RecV = St->getSVal(RecExpr, NContext); 2189 if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym) 2190 InitMethodContext = CEP->getCalleeContext(); 2191 } 2192 } 2193 } 2194 2195 N = N->pred_empty() ? nullptr : *(N->pred_begin()); 2196 } 2197 2198 // If we are reporting a leak of the object that was allocated with alloc, 2199 // mark its init method as interesting. 2200 const LocationContext *InterestingMethodContext = nullptr; 2201 if (InitMethodContext) { 2202 const ProgramPoint AllocPP = AllocationNode->getLocation(); 2203 if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>()) 2204 if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>()) 2205 if (ME->getMethodFamily() == OMF_alloc) 2206 InterestingMethodContext = InitMethodContext; 2207 } 2208 2209 // If allocation happened in a function different from the leak node context, 2210 // do not report the binding. 2211 assert(N && "Could not find allocation node"); 2212 if (N->getLocationContext() != LeakContext) { 2213 FirstBinding = nullptr; 2214 } 2215 2216 return AllocationInfo(AllocationNodeInCurrentContext, 2217 FirstBinding, 2218 InterestingMethodContext); 2219 } 2220 2221 PathDiagnosticPiece* 2222 CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2223 const ExplodedNode *EndN, 2224 BugReport &BR) { 2225 BR.markInteresting(Sym); 2226 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2227 } 2228 2229 PathDiagnosticPiece* 2230 CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2231 const ExplodedNode *EndN, 2232 BugReport &BR) { 2233 2234 // Tell the BugReporterContext to report cases when the tracked symbol is 2235 // assigned to different variables, etc. 2236 BR.markInteresting(Sym); 2237 2238 // We are reporting a leak. Walk up the graph to get to the first node where 2239 // the symbol appeared, and also get the first VarDecl that tracked object 2240 // is stored to. 2241 AllocationInfo AllocI = 2242 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2243 2244 const MemRegion* FirstBinding = AllocI.R; 2245 BR.markInteresting(AllocI.InterestingMethodContext); 2246 2247 SourceManager& SM = BRC.getSourceManager(); 2248 2249 // Compute an actual location for the leak. Sometimes a leak doesn't 2250 // occur at an actual statement (e.g., transition between blocks; end 2251 // of function) so we need to walk the graph and compute a real location. 2252 const ExplodedNode *LeakN = EndN; 2253 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2254 2255 std::string sbuf; 2256 llvm::raw_string_ostream os(sbuf); 2257 2258 os << "Object leaked: "; 2259 2260 if (FirstBinding) { 2261 os << "object allocated and stored into '" 2262 << FirstBinding->getString() << '\''; 2263 } 2264 else 2265 os << "allocated object"; 2266 2267 // Get the retain count. 2268 const RefVal* RV = getRefBinding(EndN->getState(), Sym); 2269 assert(RV); 2270 2271 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2272 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2273 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2274 // to the caller for NS objects. 2275 const Decl *D = &EndN->getCodeDecl(); 2276 2277 os << (isa<ObjCMethodDecl>(D) ? " is returned from a method " 2278 : " is returned from a function "); 2279 2280 if (D->hasAttr<CFReturnsNotRetainedAttr>()) 2281 os << "that is annotated as CF_RETURNS_NOT_RETAINED"; 2282 else if (D->hasAttr<NSReturnsNotRetainedAttr>()) 2283 os << "that is annotated as NS_RETURNS_NOT_RETAINED"; 2284 else { 2285 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2286 os << "whose name ('" << MD->getSelector().getAsString() 2287 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2288 " This violates the naming convention rules" 2289 " given in the Memory Management Guide for Cocoa"; 2290 } 2291 else { 2292 const FunctionDecl *FD = cast<FunctionDecl>(D); 2293 os << "whose name ('" << *FD 2294 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2295 " convention rules given in the Memory Management Guide for Core" 2296 " Foundation"; 2297 } 2298 } 2299 } 2300 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2301 const ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2302 os << " and returned from method '" << MD.getSelector().getAsString() 2303 << "' is potentially leaked when using garbage collection. Callers " 2304 "of this method do not expect a returned object with a +1 retain " 2305 "count since they expect the object to be managed by the garbage " 2306 "collector"; 2307 } 2308 else 2309 os << " is not referenced later in this execution path and has a retain " 2310 "count of +" << RV->getCount(); 2311 2312 return new PathDiagnosticEventPiece(L, os.str()); 2313 } 2314 2315 CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2316 bool GCEnabled, const SummaryLogTy &Log, 2317 ExplodedNode *n, SymbolRef sym, 2318 CheckerContext &Ctx, 2319 bool IncludeAllocationLine) 2320 : CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2321 2322 // Most bug reports are cached at the location where they occurred. 2323 // With leaks, we want to unique them by the location where they were 2324 // allocated, and only report a single path. To do this, we need to find 2325 // the allocation site of a piece of tracked memory, which we do via a 2326 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2327 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2328 // that all ancestor nodes that represent the allocation site have the 2329 // same SourceLocation. 2330 const ExplodedNode *AllocNode = nullptr; 2331 2332 const SourceManager& SMgr = Ctx.getSourceManager(); 2333 2334 AllocationInfo AllocI = 2335 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2336 2337 AllocNode = AllocI.N; 2338 AllocBinding = AllocI.R; 2339 markInteresting(AllocI.InterestingMethodContext); 2340 2341 // Get the SourceLocation for the allocation site. 2342 // FIXME: This will crash the analyzer if an allocation comes from an 2343 // implicit call (ex: a destructor call). 2344 // (Currently there are no such allocations in Cocoa, though.) 2345 const Stmt *AllocStmt = 0; 2346 ProgramPoint P = AllocNode->getLocation(); 2347 if (Optional<CallExitEnd> Exit = P.getAs<CallExitEnd>()) 2348 AllocStmt = Exit->getCalleeContext()->getCallSite(); 2349 else { 2350 // We are going to get a BlockEdge when the leak and allocation happen in 2351 // different, non-nested frames (contexts). For example, the case where an 2352 // allocation happens in a block that captures a reference to it and 2353 // that reference is overwritten/dropped by another call to the block. 2354 if (Optional<BlockEdge> Edge = P.getAs<BlockEdge>()) { 2355 if (Optional<CFGStmt> St = Edge->getDst()->front().getAs<CFGStmt>()) { 2356 AllocStmt = St->getStmt(); 2357 } 2358 } 2359 else { 2360 AllocStmt = P.castAs<PostStmt>().getStmt(); 2361 } 2362 } 2363 assert(AllocStmt && "Cannot find allocation statement"); 2364 2365 PathDiagnosticLocation AllocLocation = 2366 PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2367 AllocNode->getLocationContext()); 2368 Location = AllocLocation; 2369 2370 // Set uniqieing info, which will be used for unique the bug reports. The 2371 // leaks should be uniqued on the allocation site. 2372 UniqueingLocation = AllocLocation; 2373 UniqueingDecl = AllocNode->getLocationContext()->getDecl(); 2374 2375 // Fill in the description of the bug. 2376 Description.clear(); 2377 llvm::raw_string_ostream os(Description); 2378 os << "Potential leak "; 2379 if (GCEnabled) 2380 os << "(when using garbage collection) "; 2381 os << "of an object"; 2382 2383 if (AllocBinding) { 2384 os << " stored into '" << AllocBinding->getString() << '\''; 2385 if (IncludeAllocationLine) { 2386 FullSourceLoc SL(AllocStmt->getLocStart(), Ctx.getSourceManager()); 2387 os << " (allocated on line " << SL.getSpellingLineNumber() << ")"; 2388 } 2389 } 2390 2391 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2392 } 2393 2394 //===----------------------------------------------------------------------===// 2395 // Main checker logic. 2396 //===----------------------------------------------------------------------===// 2397 2398 namespace { 2399 class RetainCountChecker 2400 : public Checker< check::Bind, 2401 check::DeadSymbols, 2402 check::EndAnalysis, 2403 check::EndFunction, 2404 check::PostStmt<BlockExpr>, 2405 check::PostStmt<CastExpr>, 2406 check::PostStmt<ObjCArrayLiteral>, 2407 check::PostStmt<ObjCDictionaryLiteral>, 2408 check::PostStmt<ObjCBoxedExpr>, 2409 check::PostStmt<ObjCIvarRefExpr>, 2410 check::PostCall, 2411 check::PreStmt<ReturnStmt>, 2412 check::RegionChanges, 2413 eval::Assume, 2414 eval::Call > { 2415 mutable std::unique_ptr<CFRefBug> useAfterRelease, releaseNotOwned; 2416 mutable std::unique_ptr<CFRefBug> deallocGC, deallocNotOwned; 2417 mutable std::unique_ptr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2418 mutable std::unique_ptr<CFRefBug> leakWithinFunction, leakAtReturn; 2419 mutable std::unique_ptr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2420 2421 typedef llvm::DenseMap<SymbolRef, const CheckerProgramPointTag *> SymbolTagMap; 2422 2423 // This map is only used to ensure proper deletion of any allocated tags. 2424 mutable SymbolTagMap DeadSymbolTags; 2425 2426 mutable std::unique_ptr<RetainSummaryManager> Summaries; 2427 mutable std::unique_ptr<RetainSummaryManager> SummariesGC; 2428 mutable SummaryLogTy SummaryLog; 2429 mutable bool ShouldResetSummaryLog; 2430 2431 /// Optional setting to indicate if leak reports should include 2432 /// the allocation line. 2433 mutable bool IncludeAllocationLine; 2434 2435 public: 2436 RetainCountChecker(AnalyzerOptions &AO) 2437 : ShouldResetSummaryLog(false), 2438 IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {} 2439 2440 virtual ~RetainCountChecker() { 2441 DeleteContainerSeconds(DeadSymbolTags); 2442 } 2443 2444 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2445 ExprEngine &Eng) const { 2446 // FIXME: This is a hack to make sure the summary log gets cleared between 2447 // analyses of different code bodies. 2448 // 2449 // Why is this necessary? Because a checker's lifetime is tied to a 2450 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2451 // Once in a blue moon, a new ExplodedNode will have the same address as an 2452 // old one with an associated summary, and the bug report visitor gets very 2453 // confused. (To make things worse, the summary lifetime is currently also 2454 // tied to a code body, so we get a crash instead of incorrect results.) 2455 // 2456 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2457 // changes, things will start going wrong again. Really the lifetime of this 2458 // log needs to be tied to either the specific nodes in it or the entire 2459 // ExplodedGraph, not to a specific part of the code being analyzed. 2460 // 2461 // (Also, having stateful local data means that the same checker can't be 2462 // used from multiple threads, but a lot of checkers have incorrect 2463 // assumptions about that anyway. So that wasn't a priority at the time of 2464 // this fix.) 2465 // 2466 // This happens at the end of analysis, but bug reports are emitted /after/ 2467 // this point. So we can't just clear the summary log now. Instead, we mark 2468 // that the next time we access the summary log, it should be cleared. 2469 2470 // If we never reset the summary log during /this/ code body analysis, 2471 // there were no new summaries. There might still have been summaries from 2472 // the /last/ analysis, so clear them out to make sure the bug report 2473 // visitors don't get confused. 2474 if (ShouldResetSummaryLog) 2475 SummaryLog.clear(); 2476 2477 ShouldResetSummaryLog = !SummaryLog.empty(); 2478 } 2479 2480 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2481 bool GCEnabled) const { 2482 if (GCEnabled) { 2483 if (!leakWithinFunctionGC) 2484 leakWithinFunctionGC.reset(new Leak(this, "Leak of object when using " 2485 "garbage collection")); 2486 return leakWithinFunctionGC.get(); 2487 } else { 2488 if (!leakWithinFunction) { 2489 if (LOpts.getGC() == LangOptions::HybridGC) { 2490 leakWithinFunction.reset(new Leak(this, 2491 "Leak of object when not using " 2492 "garbage collection (GC) in " 2493 "dual GC/non-GC code")); 2494 } else { 2495 leakWithinFunction.reset(new Leak(this, "Leak")); 2496 } 2497 } 2498 return leakWithinFunction.get(); 2499 } 2500 } 2501 2502 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2503 if (GCEnabled) { 2504 if (!leakAtReturnGC) 2505 leakAtReturnGC.reset(new Leak(this, 2506 "Leak of returned object when using " 2507 "garbage collection")); 2508 return leakAtReturnGC.get(); 2509 } else { 2510 if (!leakAtReturn) { 2511 if (LOpts.getGC() == LangOptions::HybridGC) { 2512 leakAtReturn.reset(new Leak(this, 2513 "Leak of returned object when not using " 2514 "garbage collection (GC) in dual " 2515 "GC/non-GC code")); 2516 } else { 2517 leakAtReturn.reset(new Leak(this, "Leak of returned object")); 2518 } 2519 } 2520 return leakAtReturn.get(); 2521 } 2522 } 2523 2524 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2525 bool GCEnabled) const { 2526 // FIXME: We don't support ARC being turned on and off during one analysis. 2527 // (nor, for that matter, do we support changing ASTContexts) 2528 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2529 if (GCEnabled) { 2530 if (!SummariesGC) 2531 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2532 else 2533 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2534 return *SummariesGC; 2535 } else { 2536 if (!Summaries) 2537 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2538 else 2539 assert(Summaries->isARCEnabled() == ARCEnabled); 2540 return *Summaries; 2541 } 2542 } 2543 2544 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2545 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2546 } 2547 2548 void printState(raw_ostream &Out, ProgramStateRef State, 2549 const char *NL, const char *Sep) const override; 2550 2551 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2552 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2553 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2554 2555 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2556 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2557 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2558 2559 void checkPostStmt(const ObjCIvarRefExpr *IRE, CheckerContext &C) const; 2560 2561 void checkPostCall(const CallEvent &Call, CheckerContext &C) const; 2562 2563 void checkSummary(const RetainSummary &Summ, const CallEvent &Call, 2564 CheckerContext &C) const; 2565 2566 void processSummaryOfInlined(const RetainSummary &Summ, 2567 const CallEvent &Call, 2568 CheckerContext &C) const; 2569 2570 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2571 2572 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2573 bool Assumption) const; 2574 2575 ProgramStateRef 2576 checkRegionChanges(ProgramStateRef state, 2577 const InvalidatedSymbols *invalidated, 2578 ArrayRef<const MemRegion *> ExplicitRegions, 2579 ArrayRef<const MemRegion *> Regions, 2580 const CallEvent *Call) const; 2581 2582 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2583 return true; 2584 } 2585 2586 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2587 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2588 ExplodedNode *Pred, RetEffect RE, RefVal X, 2589 SymbolRef Sym, ProgramStateRef state) const; 2590 2591 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2592 void checkEndFunction(CheckerContext &C) const; 2593 2594 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2595 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2596 CheckerContext &C) const; 2597 2598 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2599 RefVal::Kind ErrorKind, SymbolRef Sym, 2600 CheckerContext &C) const; 2601 2602 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2603 2604 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2605 2606 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2607 SymbolRef sid, RefVal V, 2608 SmallVectorImpl<SymbolRef> &Leaked) const; 2609 2610 ProgramStateRef 2611 handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred, 2612 const ProgramPointTag *Tag, CheckerContext &Ctx, 2613 SymbolRef Sym, RefVal V) const; 2614 2615 ExplodedNode *processLeaks(ProgramStateRef state, 2616 SmallVectorImpl<SymbolRef> &Leaked, 2617 CheckerContext &Ctx, 2618 ExplodedNode *Pred = nullptr) const; 2619 }; 2620 } // end anonymous namespace 2621 2622 namespace { 2623 class StopTrackingCallback : public SymbolVisitor { 2624 ProgramStateRef state; 2625 public: 2626 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2627 ProgramStateRef getState() const { return state; } 2628 2629 bool VisitSymbol(SymbolRef sym) override { 2630 state = state->remove<RefBindings>(sym); 2631 return true; 2632 } 2633 }; 2634 } // end anonymous namespace 2635 2636 //===----------------------------------------------------------------------===// 2637 // Handle statements that may have an effect on refcounts. 2638 //===----------------------------------------------------------------------===// 2639 2640 void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2641 CheckerContext &C) const { 2642 2643 // Scan the BlockDecRefExprs for any object the retain count checker 2644 // may be tracking. 2645 if (!BE->getBlockDecl()->hasCaptures()) 2646 return; 2647 2648 ProgramStateRef state = C.getState(); 2649 const BlockDataRegion *R = 2650 cast<BlockDataRegion>(state->getSVal(BE, 2651 C.getLocationContext()).getAsRegion()); 2652 2653 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2654 E = R->referenced_vars_end(); 2655 2656 if (I == E) 2657 return; 2658 2659 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2660 // via captured variables, even though captured variables result in a copy 2661 // and in implicit increment/decrement of a retain count. 2662 SmallVector<const MemRegion*, 10> Regions; 2663 const LocationContext *LC = C.getLocationContext(); 2664 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2665 2666 for ( ; I != E; ++I) { 2667 const VarRegion *VR = I.getCapturedRegion(); 2668 if (VR->getSuperRegion() == R) { 2669 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2670 } 2671 Regions.push_back(VR); 2672 } 2673 2674 state = 2675 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2676 Regions.data() + Regions.size()).getState(); 2677 C.addTransition(state); 2678 } 2679 2680 void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2681 CheckerContext &C) const { 2682 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2683 if (!BE) 2684 return; 2685 2686 ArgEffect AE = IncRef; 2687 2688 switch (BE->getBridgeKind()) { 2689 case clang::OBC_Bridge: 2690 // Do nothing. 2691 return; 2692 case clang::OBC_BridgeRetained: 2693 AE = IncRef; 2694 break; 2695 case clang::OBC_BridgeTransfer: 2696 AE = DecRefBridgedTransferred; 2697 break; 2698 } 2699 2700 ProgramStateRef state = C.getState(); 2701 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2702 if (!Sym) 2703 return; 2704 const RefVal* T = getRefBinding(state, Sym); 2705 if (!T) 2706 return; 2707 2708 RefVal::Kind hasErr = (RefVal::Kind) 0; 2709 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2710 2711 if (hasErr) { 2712 // FIXME: If we get an error during a bridge cast, should we report it? 2713 // Should we assert that there is no error? 2714 return; 2715 } 2716 2717 C.addTransition(state); 2718 } 2719 2720 void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2721 const Expr *Ex) const { 2722 ProgramStateRef state = C.getState(); 2723 const ExplodedNode *pred = C.getPredecessor(); 2724 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2725 it != et ; ++it) { 2726 const Stmt *child = *it; 2727 SVal V = state->getSVal(child, pred->getLocationContext()); 2728 if (SymbolRef sym = V.getAsSymbol()) 2729 if (const RefVal* T = getRefBinding(state, sym)) { 2730 RefVal::Kind hasErr = (RefVal::Kind) 0; 2731 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2732 if (hasErr) { 2733 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2734 return; 2735 } 2736 } 2737 } 2738 2739 // Return the object as autoreleased. 2740 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2741 if (SymbolRef sym = 2742 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2743 QualType ResultTy = Ex->getType(); 2744 state = setRefBinding(state, sym, 2745 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2746 } 2747 2748 C.addTransition(state); 2749 } 2750 2751 void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2752 CheckerContext &C) const { 2753 // Apply the 'MayEscape' to all values. 2754 processObjCLiterals(C, AL); 2755 } 2756 2757 void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2758 CheckerContext &C) const { 2759 // Apply the 'MayEscape' to all keys and values. 2760 processObjCLiterals(C, DL); 2761 } 2762 2763 void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2764 CheckerContext &C) const { 2765 const ExplodedNode *Pred = C.getPredecessor(); 2766 const LocationContext *LCtx = Pred->getLocationContext(); 2767 ProgramStateRef State = Pred->getState(); 2768 2769 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2770 QualType ResultTy = Ex->getType(); 2771 State = setRefBinding(State, Sym, 2772 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2773 } 2774 2775 C.addTransition(State); 2776 } 2777 2778 void RetainCountChecker::checkPostStmt(const ObjCIvarRefExpr *IRE, 2779 CheckerContext &C) const { 2780 ProgramStateRef State = C.getState(); 2781 // If an instance variable was previously accessed through a property, 2782 // it may have a synthesized refcount of +0. Override right now that we're 2783 // doing direct access. 2784 if (Optional<Loc> IVarLoc = C.getSVal(IRE).getAs<Loc>()) 2785 if (SymbolRef Sym = State->getSVal(*IVarLoc).getAsSymbol()) 2786 if (const RefVal *RV = getRefBinding(State, Sym)) 2787 if (RV->isOverridable()) 2788 State = removeRefBinding(State, Sym); 2789 C.addTransition(State); 2790 } 2791 2792 void RetainCountChecker::checkPostCall(const CallEvent &Call, 2793 CheckerContext &C) const { 2794 RetainSummaryManager &Summaries = getSummaryManager(C); 2795 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState()); 2796 2797 if (C.wasInlined) { 2798 processSummaryOfInlined(*Summ, Call, C); 2799 return; 2800 } 2801 checkSummary(*Summ, Call, C); 2802 } 2803 2804 /// GetReturnType - Used to get the return type of a message expression or 2805 /// function call with the intention of affixing that type to a tracked symbol. 2806 /// While the return type can be queried directly from RetEx, when 2807 /// invoking class methods we augment to the return type to be that of 2808 /// a pointer to the class (as opposed it just being id). 2809 // FIXME: We may be able to do this with related result types instead. 2810 // This function is probably overestimating. 2811 static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2812 QualType RetTy = RetE->getType(); 2813 // If RetE is not a message expression just return its type. 2814 // If RetE is a message expression, return its types if it is something 2815 /// more specific than id. 2816 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2817 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2818 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2819 PT->isObjCClassType()) { 2820 // At this point we know the return type of the message expression is 2821 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2822 // is a call to a class method whose type we can resolve. In such 2823 // cases, promote the return type to XXX* (where XXX is the class). 2824 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2825 return !D ? RetTy : 2826 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2827 } 2828 2829 return RetTy; 2830 } 2831 2832 static bool wasSynthesizedProperty(const ObjCMethodCall *Call, 2833 ExplodedNode *N) { 2834 if (!Call || !Call->getDecl()->isPropertyAccessor()) 2835 return false; 2836 2837 CallExitEnd PP = N->getLocation().castAs<CallExitEnd>(); 2838 const StackFrameContext *Frame = PP.getCalleeContext(); 2839 return Frame->getAnalysisDeclContext()->isBodyAutosynthesized(); 2840 } 2841 2842 // We don't always get the exact modeling of the function with regards to the 2843 // retain count checker even when the function is inlined. For example, we need 2844 // to stop tracking the symbols which were marked with StopTrackingHard. 2845 void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ, 2846 const CallEvent &CallOrMsg, 2847 CheckerContext &C) const { 2848 ProgramStateRef state = C.getState(); 2849 2850 // Evaluate the effect of the arguments. 2851 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2852 if (Summ.getArg(idx) == StopTrackingHard) { 2853 SVal V = CallOrMsg.getArgSVal(idx); 2854 if (SymbolRef Sym = V.getAsLocSymbol()) { 2855 state = removeRefBinding(state, Sym); 2856 } 2857 } 2858 } 2859 2860 // Evaluate the effect on the message receiver. 2861 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2862 if (MsgInvocation) { 2863 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2864 if (Summ.getReceiverEffect() == StopTrackingHard) { 2865 state = removeRefBinding(state, Sym); 2866 } 2867 } 2868 } 2869 2870 // Consult the summary for the return value. 2871 RetEffect RE = Summ.getRetEffect(); 2872 if (RE.getKind() == RetEffect::NoRetHard) { 2873 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2874 if (Sym) 2875 state = removeRefBinding(state, Sym); 2876 } else if (RE.getKind() == RetEffect::NotOwnedSymbol) { 2877 if (wasSynthesizedProperty(MsgInvocation, C.getPredecessor())) { 2878 // Believe the summary if we synthesized the body of a property getter 2879 // and the return value is currently untracked. If the corresponding 2880 // instance variable is later accessed directly, however, we're going to 2881 // want to override this state, so that the owning object can perform 2882 // reference counting operations on its own ivars. 2883 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2884 if (Sym && !getRefBinding(state, Sym)) 2885 state = setRefBinding(state, Sym, 2886 RefVal::makeOverridableNotOwned(RE.getObjKind(), 2887 Sym->getType())); 2888 } 2889 } 2890 2891 C.addTransition(state); 2892 } 2893 2894 void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2895 const CallEvent &CallOrMsg, 2896 CheckerContext &C) const { 2897 ProgramStateRef state = C.getState(); 2898 2899 // Evaluate the effect of the arguments. 2900 RefVal::Kind hasErr = (RefVal::Kind) 0; 2901 SourceRange ErrorRange; 2902 SymbolRef ErrorSym = nullptr; 2903 2904 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2905 SVal V = CallOrMsg.getArgSVal(idx); 2906 2907 if (SymbolRef Sym = V.getAsLocSymbol()) { 2908 if (const RefVal *T = getRefBinding(state, Sym)) { 2909 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2910 if (hasErr) { 2911 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2912 ErrorSym = Sym; 2913 break; 2914 } 2915 } 2916 } 2917 } 2918 2919 // Evaluate the effect on the message receiver. 2920 bool ReceiverIsTracked = false; 2921 if (!hasErr) { 2922 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2923 if (MsgInvocation) { 2924 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2925 if (const RefVal *T = getRefBinding(state, Sym)) { 2926 ReceiverIsTracked = true; 2927 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2928 hasErr, C); 2929 if (hasErr) { 2930 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange(); 2931 ErrorSym = Sym; 2932 } 2933 } 2934 } 2935 } 2936 } 2937 2938 // Process any errors. 2939 if (hasErr) { 2940 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2941 return; 2942 } 2943 2944 // Consult the summary for the return value. 2945 RetEffect RE = Summ.getRetEffect(); 2946 2947 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2948 if (ReceiverIsTracked) 2949 RE = getSummaryManager(C).getObjAllocRetEffect(); 2950 else 2951 RE = RetEffect::MakeNoRet(); 2952 } 2953 2954 switch (RE.getKind()) { 2955 default: 2956 llvm_unreachable("Unhandled RetEffect."); 2957 2958 case RetEffect::NoRet: 2959 case RetEffect::NoRetHard: 2960 // No work necessary. 2961 break; 2962 2963 case RetEffect::OwnedAllocatedSymbol: 2964 case RetEffect::OwnedSymbol: { 2965 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2966 if (!Sym) 2967 break; 2968 2969 // Use the result type from the CallEvent as it automatically adjusts 2970 // for methods/functions that return references. 2971 QualType ResultTy = CallOrMsg.getResultType(); 2972 state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(), 2973 ResultTy)); 2974 2975 // FIXME: Add a flag to the checker where allocations are assumed to 2976 // *not* fail. 2977 break; 2978 } 2979 2980 case RetEffect::GCNotOwnedSymbol: 2981 case RetEffect::NotOwnedSymbol: { 2982 const Expr *Ex = CallOrMsg.getOriginExpr(); 2983 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2984 if (!Sym) 2985 break; 2986 assert(Ex); 2987 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2988 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2989 state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(), 2990 ResultTy)); 2991 break; 2992 } 2993 } 2994 2995 // This check is actually necessary; otherwise the statement builder thinks 2996 // we've hit a previously-found path. 2997 // Normally addTransition takes care of this, but we want the node pointer. 2998 ExplodedNode *NewNode; 2999 if (state == C.getState()) { 3000 NewNode = C.getPredecessor(); 3001 } else { 3002 NewNode = C.addTransition(state); 3003 } 3004 3005 // Annotate the node with summary we used. 3006 if (NewNode) { 3007 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 3008 if (ShouldResetSummaryLog) { 3009 SummaryLog.clear(); 3010 ShouldResetSummaryLog = false; 3011 } 3012 SummaryLog[NewNode] = &Summ; 3013 } 3014 } 3015 3016 3017 ProgramStateRef 3018 RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 3019 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 3020 CheckerContext &C) const { 3021 // In GC mode [... release] and [... retain] do nothing. 3022 // In ARC mode they shouldn't exist at all, but we just ignore them. 3023 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 3024 if (!IgnoreRetainMsg) 3025 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 3026 3027 switch (E) { 3028 default: 3029 break; 3030 case IncRefMsg: 3031 E = IgnoreRetainMsg ? DoNothing : IncRef; 3032 break; 3033 case DecRefMsg: 3034 E = IgnoreRetainMsg ? DoNothing : DecRef; 3035 break; 3036 case DecRefMsgAndStopTrackingHard: 3037 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard; 3038 break; 3039 case MakeCollectable: 3040 E = C.isObjCGCEnabled() ? DecRef : DoNothing; 3041 break; 3042 } 3043 3044 // Handle all use-after-releases. 3045 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 3046 V = V ^ RefVal::ErrorUseAfterRelease; 3047 hasErr = V.getKind(); 3048 return setRefBinding(state, sym, V); 3049 } 3050 3051 switch (E) { 3052 case DecRefMsg: 3053 case IncRefMsg: 3054 case MakeCollectable: 3055 case DecRefMsgAndStopTrackingHard: 3056 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 3057 3058 case Dealloc: 3059 // Any use of -dealloc in GC is *bad*. 3060 if (C.isObjCGCEnabled()) { 3061 V = V ^ RefVal::ErrorDeallocGC; 3062 hasErr = V.getKind(); 3063 break; 3064 } 3065 3066 switch (V.getKind()) { 3067 default: 3068 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 3069 case RefVal::Owned: 3070 // The object immediately transitions to the released state. 3071 V = V ^ RefVal::Released; 3072 V.clearCounts(); 3073 return setRefBinding(state, sym, V); 3074 case RefVal::NotOwned: 3075 V = V ^ RefVal::ErrorDeallocNotOwned; 3076 hasErr = V.getKind(); 3077 break; 3078 } 3079 break; 3080 3081 case MayEscape: 3082 if (V.getKind() == RefVal::Owned) { 3083 V = V ^ RefVal::NotOwned; 3084 break; 3085 } 3086 3087 // Fall-through. 3088 3089 case DoNothing: 3090 return state; 3091 3092 case Autorelease: 3093 if (C.isObjCGCEnabled()) 3094 return state; 3095 // Update the autorelease counts. 3096 V = V.autorelease(); 3097 break; 3098 3099 case StopTracking: 3100 case StopTrackingHard: 3101 return removeRefBinding(state, sym); 3102 3103 case IncRef: 3104 switch (V.getKind()) { 3105 default: 3106 llvm_unreachable("Invalid RefVal state for a retain."); 3107 case RefVal::Owned: 3108 case RefVal::NotOwned: 3109 V = V + 1; 3110 break; 3111 case RefVal::Released: 3112 // Non-GC cases are handled above. 3113 assert(C.isObjCGCEnabled()); 3114 V = (V ^ RefVal::Owned) + 1; 3115 break; 3116 } 3117 break; 3118 3119 case DecRef: 3120 case DecRefBridgedTransferred: 3121 case DecRefAndStopTrackingHard: 3122 switch (V.getKind()) { 3123 default: 3124 // case 'RefVal::Released' handled above. 3125 llvm_unreachable("Invalid RefVal state for a release."); 3126 3127 case RefVal::Owned: 3128 assert(V.getCount() > 0); 3129 if (V.getCount() == 1) 3130 V = V ^ (E == DecRefBridgedTransferred ? RefVal::NotOwned 3131 : RefVal::Released); 3132 else if (E == DecRefAndStopTrackingHard) 3133 return removeRefBinding(state, sym); 3134 3135 V = V - 1; 3136 break; 3137 3138 case RefVal::NotOwned: 3139 if (V.getCount() > 0) { 3140 if (E == DecRefAndStopTrackingHard) 3141 return removeRefBinding(state, sym); 3142 V = V - 1; 3143 } else { 3144 V = V ^ RefVal::ErrorReleaseNotOwned; 3145 hasErr = V.getKind(); 3146 } 3147 break; 3148 3149 case RefVal::Released: 3150 // Non-GC cases are handled above. 3151 assert(C.isObjCGCEnabled()); 3152 V = V ^ RefVal::ErrorUseAfterRelease; 3153 hasErr = V.getKind(); 3154 break; 3155 } 3156 break; 3157 } 3158 return setRefBinding(state, sym, V); 3159 } 3160 3161 void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3162 SourceRange ErrorRange, 3163 RefVal::Kind ErrorKind, 3164 SymbolRef Sym, 3165 CheckerContext &C) const { 3166 ExplodedNode *N = C.generateSink(St); 3167 if (!N) 3168 return; 3169 3170 CFRefBug *BT; 3171 switch (ErrorKind) { 3172 default: 3173 llvm_unreachable("Unhandled error."); 3174 case RefVal::ErrorUseAfterRelease: 3175 if (!useAfterRelease) 3176 useAfterRelease.reset(new UseAfterRelease(this)); 3177 BT = &*useAfterRelease; 3178 break; 3179 case RefVal::ErrorReleaseNotOwned: 3180 if (!releaseNotOwned) 3181 releaseNotOwned.reset(new BadRelease(this)); 3182 BT = &*releaseNotOwned; 3183 break; 3184 case RefVal::ErrorDeallocGC: 3185 if (!deallocGC) 3186 deallocGC.reset(new DeallocGC(this)); 3187 BT = &*deallocGC; 3188 break; 3189 case RefVal::ErrorDeallocNotOwned: 3190 if (!deallocNotOwned) 3191 deallocNotOwned.reset(new DeallocNotOwned(this)); 3192 BT = &*deallocNotOwned; 3193 break; 3194 } 3195 3196 assert(BT); 3197 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3198 C.isObjCGCEnabled(), SummaryLog, 3199 N, Sym); 3200 report->addRange(ErrorRange); 3201 C.emitReport(report); 3202 } 3203 3204 //===----------------------------------------------------------------------===// 3205 // Handle the return values of retain-count-related functions. 3206 //===----------------------------------------------------------------------===// 3207 3208 bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3209 // Get the callee. We're only interested in simple C functions. 3210 ProgramStateRef state = C.getState(); 3211 const FunctionDecl *FD = C.getCalleeDecl(CE); 3212 if (!FD) 3213 return false; 3214 3215 IdentifierInfo *II = FD->getIdentifier(); 3216 if (!II) 3217 return false; 3218 3219 // For now, we're only handling the functions that return aliases of their 3220 // arguments: CFRetain and CFMakeCollectable (and their families). 3221 // Eventually we should add other functions we can model entirely, 3222 // such as CFRelease, which don't invalidate their arguments or globals. 3223 if (CE->getNumArgs() != 1) 3224 return false; 3225 3226 // Get the name of the function. 3227 StringRef FName = II->getName(); 3228 FName = FName.substr(FName.find_first_not_of('_')); 3229 3230 // See if it's one of the specific functions we know how to eval. 3231 bool canEval = false; 3232 3233 QualType ResultTy = CE->getCallReturnType(); 3234 if (ResultTy->isObjCIdType()) { 3235 // Handle: id NSMakeCollectable(CFTypeRef) 3236 canEval = II->isStr("NSMakeCollectable"); 3237 } else if (ResultTy->isPointerType()) { 3238 // Handle: (CF|CG)Retain 3239 // CFAutorelease 3240 // CFMakeCollectable 3241 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3242 if (cocoa::isRefType(ResultTy, "CF", FName) || 3243 cocoa::isRefType(ResultTy, "CG", FName)) { 3244 canEval = isRetain(FD, FName) || isAutorelease(FD, FName) || 3245 isMakeCollectable(FD, FName); 3246 } 3247 } 3248 3249 if (!canEval) 3250 return false; 3251 3252 // Bind the return value. 3253 const LocationContext *LCtx = C.getLocationContext(); 3254 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3255 if (RetVal.isUnknown()) { 3256 // If the receiver is unknown, conjure a return value. 3257 SValBuilder &SVB = C.getSValBuilder(); 3258 RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, ResultTy, C.blockCount()); 3259 } 3260 state = state->BindExpr(CE, LCtx, RetVal, false); 3261 3262 // FIXME: This should not be necessary, but otherwise the argument seems to be 3263 // considered alive during the next statement. 3264 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3265 // Save the refcount status of the argument. 3266 SymbolRef Sym = RetVal.getAsLocSymbol(); 3267 const RefVal *Binding = nullptr; 3268 if (Sym) 3269 Binding = getRefBinding(state, Sym); 3270 3271 // Invalidate the argument region. 3272 state = state->invalidateRegions(ArgRegion, CE, C.blockCount(), LCtx, 3273 /*CausesPointerEscape*/ false); 3274 3275 // Restore the refcount status of the argument. 3276 if (Binding) 3277 state = setRefBinding(state, Sym, *Binding); 3278 } 3279 3280 C.addTransition(state); 3281 return true; 3282 } 3283 3284 //===----------------------------------------------------------------------===// 3285 // Handle return statements. 3286 //===----------------------------------------------------------------------===// 3287 3288 void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3289 CheckerContext &C) const { 3290 3291 // Only adjust the reference count if this is the top-level call frame, 3292 // and not the result of inlining. In the future, we should do 3293 // better checking even for inlined calls, and see if they match 3294 // with their expected semantics (e.g., the method should return a retained 3295 // object, etc.). 3296 if (!C.inTopFrame()) 3297 return; 3298 3299 const Expr *RetE = S->getRetValue(); 3300 if (!RetE) 3301 return; 3302 3303 ProgramStateRef state = C.getState(); 3304 SymbolRef Sym = 3305 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3306 if (!Sym) 3307 return; 3308 3309 // Get the reference count binding (if any). 3310 const RefVal *T = getRefBinding(state, Sym); 3311 if (!T) 3312 return; 3313 3314 // Change the reference count. 3315 RefVal X = *T; 3316 3317 switch (X.getKind()) { 3318 case RefVal::Owned: { 3319 unsigned cnt = X.getCount(); 3320 assert(cnt > 0); 3321 X.setCount(cnt - 1); 3322 X = X ^ RefVal::ReturnedOwned; 3323 break; 3324 } 3325 3326 case RefVal::NotOwned: { 3327 unsigned cnt = X.getCount(); 3328 if (cnt) { 3329 X.setCount(cnt - 1); 3330 X = X ^ RefVal::ReturnedOwned; 3331 } 3332 else { 3333 X = X ^ RefVal::ReturnedNotOwned; 3334 } 3335 break; 3336 } 3337 3338 default: 3339 return; 3340 } 3341 3342 // Update the binding. 3343 state = setRefBinding(state, Sym, X); 3344 ExplodedNode *Pred = C.addTransition(state); 3345 3346 // At this point we have updated the state properly. 3347 // Everything after this is merely checking to see if the return value has 3348 // been over- or under-retained. 3349 3350 // Did we cache out? 3351 if (!Pred) 3352 return; 3353 3354 // Update the autorelease counts. 3355 static CheckerProgramPointTag AutoreleaseTag(this, "Autorelease"); 3356 state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X); 3357 3358 // Did we cache out? 3359 if (!state) 3360 return; 3361 3362 // Get the updated binding. 3363 T = getRefBinding(state, Sym); 3364 assert(T); 3365 X = *T; 3366 3367 // Consult the summary of the enclosing method. 3368 RetainSummaryManager &Summaries = getSummaryManager(C); 3369 const Decl *CD = &Pred->getCodeDecl(); 3370 RetEffect RE = RetEffect::MakeNoRet(); 3371 3372 // FIXME: What is the convention for blocks? Is there one? 3373 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3374 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3375 RE = Summ->getRetEffect(); 3376 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3377 if (!isa<CXXMethodDecl>(FD)) { 3378 const RetainSummary *Summ = Summaries.getFunctionSummary(FD); 3379 RE = Summ->getRetEffect(); 3380 } 3381 } 3382 3383 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3384 } 3385 3386 void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3387 CheckerContext &C, 3388 ExplodedNode *Pred, 3389 RetEffect RE, RefVal X, 3390 SymbolRef Sym, 3391 ProgramStateRef state) const { 3392 // Any leaks or other errors? 3393 if (X.isReturnedOwned() && X.getCount() == 0) { 3394 if (RE.getKind() != RetEffect::NoRet) { 3395 bool hasError = false; 3396 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3397 // Things are more complicated with garbage collection. If the 3398 // returned object is suppose to be an Objective-C object, we have 3399 // a leak (as the caller expects a GC'ed object) because no 3400 // method should return ownership unless it returns a CF object. 3401 hasError = true; 3402 X = X ^ RefVal::ErrorGCLeakReturned; 3403 } 3404 else if (!RE.isOwned()) { 3405 // Either we are using GC and the returned object is a CF type 3406 // or we aren't using GC. In either case, we expect that the 3407 // enclosing method is expected to return ownership. 3408 hasError = true; 3409 X = X ^ RefVal::ErrorLeakReturned; 3410 } 3411 3412 if (hasError) { 3413 // Generate an error node. 3414 state = setRefBinding(state, Sym, X); 3415 3416 static CheckerProgramPointTag ReturnOwnLeakTag(this, "ReturnsOwnLeak"); 3417 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3418 if (N) { 3419 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3420 bool GCEnabled = C.isObjCGCEnabled(); 3421 CFRefReport *report = 3422 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3423 LOpts, GCEnabled, SummaryLog, 3424 N, Sym, C, IncludeAllocationLine); 3425 3426 C.emitReport(report); 3427 } 3428 } 3429 } 3430 } else if (X.isReturnedNotOwned()) { 3431 if (RE.isOwned()) { 3432 // Trying to return a not owned object to a caller expecting an 3433 // owned object. 3434 state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned); 3435 3436 static CheckerProgramPointTag ReturnNotOwnedTag(this, 3437 "ReturnNotOwnedForOwned"); 3438 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3439 if (N) { 3440 if (!returnNotOwnedForOwned) 3441 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned(this)); 3442 3443 CFRefReport *report = 3444 new CFRefReport(*returnNotOwnedForOwned, 3445 C.getASTContext().getLangOpts(), 3446 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3447 C.emitReport(report); 3448 } 3449 } 3450 } 3451 } 3452 3453 //===----------------------------------------------------------------------===// 3454 // Check various ways a symbol can be invalidated. 3455 //===----------------------------------------------------------------------===// 3456 3457 void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3458 CheckerContext &C) const { 3459 // Are we storing to something that causes the value to "escape"? 3460 bool escapes = true; 3461 3462 // A value escapes in three possible cases (this may change): 3463 // 3464 // (1) we are binding to something that is not a memory region. 3465 // (2) we are binding to a memregion that does not have stack storage 3466 // (3) we are binding to a memregion with stack storage that the store 3467 // does not understand. 3468 ProgramStateRef state = C.getState(); 3469 3470 if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) { 3471 escapes = !regionLoc->getRegion()->hasStackStorage(); 3472 3473 if (!escapes) { 3474 // To test (3), generate a new state with the binding added. If it is 3475 // the same state, then it escapes (since the store cannot represent 3476 // the binding). 3477 // Do this only if we know that the store is not supposed to generate the 3478 // same state. 3479 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3480 if (StoredVal != val) 3481 escapes = (state == (state->bindLoc(*regionLoc, val))); 3482 } 3483 if (!escapes) { 3484 // Case 4: We do not currently model what happens when a symbol is 3485 // assigned to a struct field, so be conservative here and let the symbol 3486 // go. TODO: This could definitely be improved upon. 3487 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3488 } 3489 } 3490 3491 // If we are storing the value into an auto function scope variable annotated 3492 // with (__attribute__((cleanup))), stop tracking the value to avoid leak 3493 // false positives. 3494 if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) { 3495 const VarDecl *VD = LVR->getDecl(); 3496 if (VD->hasAttr<CleanupAttr>()) { 3497 escapes = true; 3498 } 3499 } 3500 3501 // If our store can represent the binding and we aren't storing to something 3502 // that doesn't have local storage then just return and have the simulation 3503 // state continue as is. 3504 if (!escapes) 3505 return; 3506 3507 // Otherwise, find all symbols referenced by 'val' that we are tracking 3508 // and stop tracking them. 3509 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3510 C.addTransition(state); 3511 } 3512 3513 ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3514 SVal Cond, 3515 bool Assumption) const { 3516 3517 // FIXME: We may add to the interface of evalAssume the list of symbols 3518 // whose assumptions have changed. For now we just iterate through the 3519 // bindings and check if any of the tracked symbols are NULL. This isn't 3520 // too bad since the number of symbols we will track in practice are 3521 // probably small and evalAssume is only called at branches and a few 3522 // other places. 3523 RefBindingsTy B = state->get<RefBindings>(); 3524 3525 if (B.isEmpty()) 3526 return state; 3527 3528 bool changed = false; 3529 RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>(); 3530 3531 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3532 // Check if the symbol is null stop tracking the symbol. 3533 ConstraintManager &CMgr = state->getConstraintManager(); 3534 ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey()); 3535 if (AllocFailed.isConstrainedTrue()) { 3536 changed = true; 3537 B = RefBFactory.remove(B, I.getKey()); 3538 } 3539 } 3540 3541 if (changed) 3542 state = state->set<RefBindings>(B); 3543 3544 return state; 3545 } 3546 3547 ProgramStateRef 3548 RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3549 const InvalidatedSymbols *invalidated, 3550 ArrayRef<const MemRegion *> ExplicitRegions, 3551 ArrayRef<const MemRegion *> Regions, 3552 const CallEvent *Call) const { 3553 if (!invalidated) 3554 return state; 3555 3556 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3557 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3558 E = ExplicitRegions.end(); I != E; ++I) { 3559 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3560 WhitelistedSymbols.insert(SR->getSymbol()); 3561 } 3562 3563 for (InvalidatedSymbols::const_iterator I=invalidated->begin(), 3564 E = invalidated->end(); I!=E; ++I) { 3565 SymbolRef sym = *I; 3566 if (WhitelistedSymbols.count(sym)) 3567 continue; 3568 // Remove any existing reference-count binding. 3569 state = removeRefBinding(state, sym); 3570 } 3571 return state; 3572 } 3573 3574 //===----------------------------------------------------------------------===// 3575 // Handle dead symbols and end-of-path. 3576 //===----------------------------------------------------------------------===// 3577 3578 ProgramStateRef 3579 RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3580 ExplodedNode *Pred, 3581 const ProgramPointTag *Tag, 3582 CheckerContext &Ctx, 3583 SymbolRef Sym, RefVal V) const { 3584 unsigned ACnt = V.getAutoreleaseCount(); 3585 3586 // No autorelease counts? Nothing to be done. 3587 if (!ACnt) 3588 return state; 3589 3590 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3591 unsigned Cnt = V.getCount(); 3592 3593 // FIXME: Handle sending 'autorelease' to already released object. 3594 3595 if (V.getKind() == RefVal::ReturnedOwned) 3596 ++Cnt; 3597 3598 if (ACnt <= Cnt) { 3599 if (ACnt == Cnt) { 3600 V.clearCounts(); 3601 if (V.getKind() == RefVal::ReturnedOwned) 3602 V = V ^ RefVal::ReturnedNotOwned; 3603 else 3604 V = V ^ RefVal::NotOwned; 3605 } else { 3606 V.setCount(V.getCount() - ACnt); 3607 V.setAutoreleaseCount(0); 3608 } 3609 return setRefBinding(state, Sym, V); 3610 } 3611 3612 // Woah! More autorelease counts then retain counts left. 3613 // Emit hard error. 3614 V = V ^ RefVal::ErrorOverAutorelease; 3615 state = setRefBinding(state, Sym, V); 3616 3617 ExplodedNode *N = Ctx.generateSink(state, Pred, Tag); 3618 if (N) { 3619 SmallString<128> sbuf; 3620 llvm::raw_svector_ostream os(sbuf); 3621 os << "Object was autoreleased "; 3622 if (V.getAutoreleaseCount() > 1) 3623 os << V.getAutoreleaseCount() << " times but the object "; 3624 else 3625 os << "but "; 3626 os << "has a +" << V.getCount() << " retain count"; 3627 3628 if (!overAutorelease) 3629 overAutorelease.reset(new OverAutorelease(this)); 3630 3631 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3632 CFRefReport *report = 3633 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3634 SummaryLog, N, Sym, os.str()); 3635 Ctx.emitReport(report); 3636 } 3637 3638 return nullptr; 3639 } 3640 3641 ProgramStateRef 3642 RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3643 SymbolRef sid, RefVal V, 3644 SmallVectorImpl<SymbolRef> &Leaked) const { 3645 bool hasLeak = false; 3646 if (V.isOwned()) 3647 hasLeak = true; 3648 else if (V.isNotOwned() || V.isReturnedOwned()) 3649 hasLeak = (V.getCount() > 0); 3650 3651 if (!hasLeak) 3652 return removeRefBinding(state, sid); 3653 3654 Leaked.push_back(sid); 3655 return setRefBinding(state, sid, V ^ RefVal::ErrorLeak); 3656 } 3657 3658 ExplodedNode * 3659 RetainCountChecker::processLeaks(ProgramStateRef state, 3660 SmallVectorImpl<SymbolRef> &Leaked, 3661 CheckerContext &Ctx, 3662 ExplodedNode *Pred) const { 3663 // Generate an intermediate node representing the leak point. 3664 ExplodedNode *N = Ctx.addTransition(state, Pred); 3665 3666 if (N) { 3667 for (SmallVectorImpl<SymbolRef>::iterator 3668 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3669 3670 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3671 bool GCEnabled = Ctx.isObjCGCEnabled(); 3672 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3673 : getLeakAtReturnBug(LOpts, GCEnabled); 3674 assert(BT && "BugType not initialized."); 3675 3676 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3677 SummaryLog, N, *I, Ctx, 3678 IncludeAllocationLine); 3679 Ctx.emitReport(report); 3680 } 3681 } 3682 3683 return N; 3684 } 3685 3686 void RetainCountChecker::checkEndFunction(CheckerContext &Ctx) const { 3687 ProgramStateRef state = Ctx.getState(); 3688 RefBindingsTy B = state->get<RefBindings>(); 3689 ExplodedNode *Pred = Ctx.getPredecessor(); 3690 3691 // Don't process anything within synthesized bodies. 3692 const LocationContext *LCtx = Pred->getLocationContext(); 3693 if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) { 3694 assert(LCtx->getParent()); 3695 return; 3696 } 3697 3698 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3699 state = handleAutoreleaseCounts(state, Pred, /*Tag=*/nullptr, Ctx, 3700 I->first, I->second); 3701 if (!state) 3702 return; 3703 } 3704 3705 // If the current LocationContext has a parent, don't check for leaks. 3706 // We will do that later. 3707 // FIXME: we should instead check for imbalances of the retain/releases, 3708 // and suggest annotations. 3709 if (LCtx->getParent()) 3710 return; 3711 3712 B = state->get<RefBindings>(); 3713 SmallVector<SymbolRef, 10> Leaked; 3714 3715 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) 3716 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3717 3718 processLeaks(state, Leaked, Ctx, Pred); 3719 } 3720 3721 const ProgramPointTag * 3722 RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3723 const CheckerProgramPointTag *&tag = DeadSymbolTags[sym]; 3724 if (!tag) { 3725 SmallString<64> buf; 3726 llvm::raw_svector_ostream out(buf); 3727 out << "Dead Symbol : "; 3728 sym->dumpToStream(out); 3729 tag = new CheckerProgramPointTag(this, out.str()); 3730 } 3731 return tag; 3732 } 3733 3734 void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3735 CheckerContext &C) const { 3736 ExplodedNode *Pred = C.getPredecessor(); 3737 3738 ProgramStateRef state = C.getState(); 3739 RefBindingsTy B = state->get<RefBindings>(); 3740 SmallVector<SymbolRef, 10> Leaked; 3741 3742 // Update counts from autorelease pools 3743 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3744 E = SymReaper.dead_end(); I != E; ++I) { 3745 SymbolRef Sym = *I; 3746 if (const RefVal *T = B.lookup(Sym)){ 3747 // Use the symbol as the tag. 3748 // FIXME: This might not be as unique as we would like. 3749 const ProgramPointTag *Tag = getDeadSymbolTag(Sym); 3750 state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T); 3751 if (!state) 3752 return; 3753 3754 // Fetch the new reference count from the state, and use it to handle 3755 // this symbol. 3756 state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked); 3757 } 3758 } 3759 3760 if (Leaked.empty()) { 3761 C.addTransition(state); 3762 return; 3763 } 3764 3765 Pred = processLeaks(state, Leaked, C, Pred); 3766 3767 // Did we cache out? 3768 if (!Pred) 3769 return; 3770 3771 // Now generate a new node that nukes the old bindings. 3772 // The only bindings left at this point are the leaked symbols. 3773 RefBindingsTy::Factory &F = state->get_context<RefBindings>(); 3774 B = state->get<RefBindings>(); 3775 3776 for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(), 3777 E = Leaked.end(); 3778 I != E; ++I) 3779 B = F.remove(B, *I); 3780 3781 state = state->set<RefBindings>(B); 3782 C.addTransition(state, Pred); 3783 } 3784 3785 void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3786 const char *NL, const char *Sep) const { 3787 3788 RefBindingsTy B = State->get<RefBindings>(); 3789 3790 if (B.isEmpty()) 3791 return; 3792 3793 Out << Sep << NL; 3794 3795 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3796 Out << I->first << " : "; 3797 I->second.print(Out); 3798 Out << NL; 3799 } 3800 } 3801 3802 //===----------------------------------------------------------------------===// 3803 // Checker registration. 3804 //===----------------------------------------------------------------------===// 3805 3806 void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3807 Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions()); 3808 } 3809 3810 //===----------------------------------------------------------------------===// 3811 // Implementation of the CallEffects API. 3812 //===----------------------------------------------------------------------===// 3813 3814 namespace clang { namespace ento { namespace objc_retain { 3815 3816 // This is a bit gross, but it allows us to populate CallEffects without 3817 // creating a bunch of accessors. This kind is very localized, so the 3818 // damage of this macro is limited. 3819 #define createCallEffect(D, KIND)\ 3820 ASTContext &Ctx = D->getASTContext();\ 3821 LangOptions L = Ctx.getLangOpts();\ 3822 RetainSummaryManager M(Ctx, L.GCOnly, L.ObjCAutoRefCount);\ 3823 const RetainSummary *S = M.get ## KIND ## Summary(D);\ 3824 CallEffects CE(S->getRetEffect());\ 3825 CE.Receiver = S->getReceiverEffect();\ 3826 unsigned N = D->param_size();\ 3827 for (unsigned i = 0; i < N; ++i) {\ 3828 CE.Args.push_back(S->getArg(i));\ 3829 } 3830 3831 CallEffects CallEffects::getEffect(const ObjCMethodDecl *MD) { 3832 createCallEffect(MD, Method); 3833 return CE; 3834 } 3835 3836 CallEffects CallEffects::getEffect(const FunctionDecl *FD) { 3837 createCallEffect(FD, Function); 3838 return CE; 3839 } 3840 3841 #undef createCallEffect 3842 3843 }}} 3844