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 "clang/AST/Attr.h" 17 #include "clang/AST/DeclCXX.h" 18 #include "clang/AST/DeclObjC.h" 19 #include "clang/AST/ParentMap.h" 20 #include "clang/Analysis/DomainSpecific/CocoaConventions.h" 21 #include "clang/Basic/LangOptions.h" 22 #include "clang/Basic/SourceManager.h" 23 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 24 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 25 #include "clang/StaticAnalyzer/Core/Checker.h" 26 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 27 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 28 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 29 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 30 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 31 #include "llvm/ADT/DenseMap.h" 32 #include "llvm/ADT/FoldingSet.h" 33 #include "llvm/ADT/ImmutableList.h" 34 #include "llvm/ADT/ImmutableMap.h" 35 #include "llvm/ADT/STLExtras.h" 36 #include "llvm/ADT/SmallString.h" 37 #include "llvm/ADT/StringExtras.h" 38 #include <cstdarg> 39 40 #include "AllocationDiagnostics.h" 41 42 using namespace clang; 43 using namespace ento; 44 using llvm::StrInStrNoCase; 45 46 //===----------------------------------------------------------------------===// 47 // Primitives used for constructing summaries for function/method calls. 48 //===----------------------------------------------------------------------===// 49 50 /// ArgEffect is used to summarize a function/method call's effect on a 51 /// particular argument. 52 enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 53 DecRefBridgedTransfered, 54 IncRefMsg, IncRef, MakeCollectable, MayEscape, 55 56 // Stop tracking the argument - the effect of the call is 57 // unknown. 58 StopTracking, 59 60 // In some cases, we obtain a better summary for this checker 61 // by looking at the call site than by inlining the function. 62 // Signifies that we should stop tracking the symbol even if 63 // the function is inlined. 64 StopTrackingHard, 65 66 // The function decrements the reference count and the checker 67 // should stop tracking the argument. 68 DecRefAndStopTrackingHard, DecRefMsgAndStopTrackingHard 69 }; 70 71 namespace llvm { 72 template <> struct FoldingSetTrait<ArgEffect> { 73 static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 74 ID.AddInteger((unsigned) X); 75 } 76 }; 77 } // end llvm namespace 78 79 /// ArgEffects summarizes the effects of a function/method call on all of 80 /// its arguments. 81 typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 82 83 namespace { 84 85 /// RetEffect is used to summarize a function/method call's behavior with 86 /// respect to its return value. 87 class RetEffect { 88 public: 89 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 90 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 91 OwnedWhenTrackedReceiver, 92 // Treat this function as returning a non-tracked symbol even if 93 // the function has been inlined. This is used where the call 94 // site summary is more presise than the summary indirectly produced 95 // by inlining the function 96 NoRetHard 97 }; 98 99 enum ObjKind { CF, ObjC, AnyObj }; 100 101 private: 102 Kind K; 103 ObjKind O; 104 105 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 106 107 public: 108 Kind getKind() const { return K; } 109 110 ObjKind getObjKind() const { return O; } 111 112 bool isOwned() const { 113 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 114 K == OwnedWhenTrackedReceiver; 115 } 116 117 bool operator==(const RetEffect &Other) const { 118 return K == Other.K && O == Other.O; 119 } 120 121 static RetEffect MakeOwnedWhenTrackedReceiver() { 122 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 123 } 124 125 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 126 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 127 } 128 static RetEffect MakeNotOwned(ObjKind o) { 129 return RetEffect(NotOwnedSymbol, o); 130 } 131 static RetEffect MakeGCNotOwned() { 132 return RetEffect(GCNotOwnedSymbol, ObjC); 133 } 134 static RetEffect MakeARCNotOwned() { 135 return RetEffect(ARCNotOwnedSymbol, ObjC); 136 } 137 static RetEffect MakeNoRet() { 138 return RetEffect(NoRet); 139 } 140 static RetEffect MakeNoRetHard() { 141 return RetEffect(NoRetHard); 142 } 143 144 void Profile(llvm::FoldingSetNodeID& ID) const { 145 ID.AddInteger((unsigned) K); 146 ID.AddInteger((unsigned) O); 147 } 148 }; 149 150 //===----------------------------------------------------------------------===// 151 // Reference-counting logic (typestate + counts). 152 //===----------------------------------------------------------------------===// 153 154 class RefVal { 155 public: 156 enum Kind { 157 Owned = 0, // Owning reference. 158 NotOwned, // Reference is not owned by still valid (not freed). 159 Released, // Object has been released. 160 ReturnedOwned, // Returned object passes ownership to caller. 161 ReturnedNotOwned, // Return object does not pass ownership to caller. 162 ERROR_START, 163 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 164 ErrorDeallocGC, // Calling -dealloc with GC enabled. 165 ErrorUseAfterRelease, // Object used after released. 166 ErrorReleaseNotOwned, // Release of an object that was not owned. 167 ERROR_LEAK_START, 168 ErrorLeak, // A memory leak due to excessive reference counts. 169 ErrorLeakReturned, // A memory leak due to the returning method not having 170 // the correct naming conventions. 171 ErrorGCLeakReturned, 172 ErrorOverAutorelease, 173 ErrorReturnedNotOwned 174 }; 175 176 private: 177 Kind kind; 178 RetEffect::ObjKind okind; 179 unsigned Cnt; 180 unsigned ACnt; 181 QualType T; 182 183 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 184 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 185 186 public: 187 Kind getKind() const { return kind; } 188 189 RetEffect::ObjKind getObjKind() const { return okind; } 190 191 unsigned getCount() const { return Cnt; } 192 unsigned getAutoreleaseCount() const { return ACnt; } 193 unsigned getCombinedCounts() const { return Cnt + ACnt; } 194 void clearCounts() { Cnt = 0; ACnt = 0; } 195 void setCount(unsigned i) { Cnt = i; } 196 void setAutoreleaseCount(unsigned i) { ACnt = i; } 197 198 QualType getType() const { return T; } 199 200 bool isOwned() const { 201 return getKind() == Owned; 202 } 203 204 bool isNotOwned() const { 205 return getKind() == NotOwned; 206 } 207 208 bool isReturnedOwned() const { 209 return getKind() == ReturnedOwned; 210 } 211 212 bool isReturnedNotOwned() const { 213 return getKind() == ReturnedNotOwned; 214 } 215 216 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 217 unsigned Count = 1) { 218 return RefVal(Owned, o, Count, 0, t); 219 } 220 221 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 222 unsigned Count = 0) { 223 return RefVal(NotOwned, o, Count, 0, t); 224 } 225 226 // Comparison, profiling, and pretty-printing. 227 228 bool operator==(const RefVal& X) const { 229 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 230 } 231 232 RefVal operator-(size_t i) const { 233 return RefVal(getKind(), getObjKind(), getCount() - i, 234 getAutoreleaseCount(), getType()); 235 } 236 237 RefVal operator+(size_t i) const { 238 return RefVal(getKind(), getObjKind(), getCount() + i, 239 getAutoreleaseCount(), getType()); 240 } 241 242 RefVal operator^(Kind k) const { 243 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 244 getType()); 245 } 246 247 RefVal autorelease() const { 248 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 249 getType()); 250 } 251 252 void Profile(llvm::FoldingSetNodeID& ID) const { 253 ID.AddInteger((unsigned) kind); 254 ID.AddInteger(Cnt); 255 ID.AddInteger(ACnt); 256 ID.Add(T); 257 } 258 259 void print(raw_ostream &Out) const; 260 }; 261 262 void RefVal::print(raw_ostream &Out) const { 263 if (!T.isNull()) 264 Out << "Tracked " << T.getAsString() << '/'; 265 266 switch (getKind()) { 267 default: llvm_unreachable("Invalid RefVal kind"); 268 case Owned: { 269 Out << "Owned"; 270 unsigned cnt = getCount(); 271 if (cnt) Out << " (+ " << cnt << ")"; 272 break; 273 } 274 275 case NotOwned: { 276 Out << "NotOwned"; 277 unsigned cnt = getCount(); 278 if (cnt) Out << " (+ " << cnt << ")"; 279 break; 280 } 281 282 case ReturnedOwned: { 283 Out << "ReturnedOwned"; 284 unsigned cnt = getCount(); 285 if (cnt) Out << " (+ " << cnt << ")"; 286 break; 287 } 288 289 case ReturnedNotOwned: { 290 Out << "ReturnedNotOwned"; 291 unsigned cnt = getCount(); 292 if (cnt) Out << " (+ " << cnt << ")"; 293 break; 294 } 295 296 case Released: 297 Out << "Released"; 298 break; 299 300 case ErrorDeallocGC: 301 Out << "-dealloc (GC)"; 302 break; 303 304 case ErrorDeallocNotOwned: 305 Out << "-dealloc (not-owned)"; 306 break; 307 308 case ErrorLeak: 309 Out << "Leaked"; 310 break; 311 312 case ErrorLeakReturned: 313 Out << "Leaked (Bad naming)"; 314 break; 315 316 case ErrorGCLeakReturned: 317 Out << "Leaked (GC-ed at return)"; 318 break; 319 320 case ErrorUseAfterRelease: 321 Out << "Use-After-Release [ERROR]"; 322 break; 323 324 case ErrorReleaseNotOwned: 325 Out << "Release of Not-Owned [ERROR]"; 326 break; 327 328 case RefVal::ErrorOverAutorelease: 329 Out << "Over-autoreleased"; 330 break; 331 332 case RefVal::ErrorReturnedNotOwned: 333 Out << "Non-owned object returned instead of owned"; 334 break; 335 } 336 337 if (ACnt) { 338 Out << " [ARC +" << ACnt << ']'; 339 } 340 } 341 } //end anonymous namespace 342 343 //===----------------------------------------------------------------------===// 344 // RefBindings - State used to track object reference counts. 345 //===----------------------------------------------------------------------===// 346 347 REGISTER_MAP_WITH_PROGRAMSTATE(RefBindings, SymbolRef, RefVal) 348 349 static inline const RefVal *getRefBinding(ProgramStateRef State, 350 SymbolRef Sym) { 351 return State->get<RefBindings>(Sym); 352 } 353 354 static inline ProgramStateRef setRefBinding(ProgramStateRef State, 355 SymbolRef Sym, RefVal Val) { 356 return State->set<RefBindings>(Sym, Val); 357 } 358 359 static ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) { 360 return State->remove<RefBindings>(Sym); 361 } 362 363 //===----------------------------------------------------------------------===// 364 // Function/Method behavior summaries. 365 //===----------------------------------------------------------------------===// 366 367 namespace { 368 class RetainSummary { 369 /// Args - a map of (index, ArgEffect) pairs, where index 370 /// specifies the argument (starting from 0). This can be sparsely 371 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 372 ArgEffects Args; 373 374 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 375 /// do not have an entry in Args. 376 ArgEffect DefaultArgEffect; 377 378 /// Receiver - If this summary applies to an Objective-C message expression, 379 /// this is the effect applied to the state of the receiver. 380 ArgEffect Receiver; 381 382 /// Ret - The effect on the return value. Used to indicate if the 383 /// function/method call returns a new tracked symbol. 384 RetEffect Ret; 385 386 public: 387 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 388 ArgEffect ReceiverEff) 389 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 390 391 /// getArg - Return the argument effect on the argument specified by 392 /// idx (starting from 0). 393 ArgEffect getArg(unsigned idx) const { 394 if (const ArgEffect *AE = Args.lookup(idx)) 395 return *AE; 396 397 return DefaultArgEffect; 398 } 399 400 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 401 Args = af.add(Args, idx, e); 402 } 403 404 /// setDefaultArgEffect - Set the default argument effect. 405 void setDefaultArgEffect(ArgEffect E) { 406 DefaultArgEffect = E; 407 } 408 409 /// getRetEffect - Returns the effect on the return value of the call. 410 RetEffect getRetEffect() const { return Ret; } 411 412 /// setRetEffect - Set the effect of the return value of the call. 413 void setRetEffect(RetEffect E) { Ret = E; } 414 415 416 /// Sets the effect on the receiver of the message. 417 void setReceiverEffect(ArgEffect e) { Receiver = e; } 418 419 /// getReceiverEffect - Returns the effect on the receiver of the call. 420 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 421 ArgEffect getReceiverEffect() const { return Receiver; } 422 423 /// Test if two retain summaries are identical. Note that merely equivalent 424 /// summaries are not necessarily identical (for example, if an explicit 425 /// argument effect matches the default effect). 426 bool operator==(const RetainSummary &Other) const { 427 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 428 Receiver == Other.Receiver && Ret == Other.Ret; 429 } 430 431 /// Profile this summary for inclusion in a FoldingSet. 432 void Profile(llvm::FoldingSetNodeID& ID) const { 433 ID.Add(Args); 434 ID.Add(DefaultArgEffect); 435 ID.Add(Receiver); 436 ID.Add(Ret); 437 } 438 439 /// A retain summary is simple if it has no ArgEffects other than the default. 440 bool isSimple() const { 441 return Args.isEmpty(); 442 } 443 444 private: 445 ArgEffects getArgEffects() const { return Args; } 446 ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; } 447 448 friend class RetainSummaryManager; 449 }; 450 } // end anonymous namespace 451 452 //===----------------------------------------------------------------------===// 453 // Data structures for constructing summaries. 454 //===----------------------------------------------------------------------===// 455 456 namespace { 457 class ObjCSummaryKey { 458 IdentifierInfo* II; 459 Selector S; 460 public: 461 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 462 : II(ii), S(s) {} 463 464 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 465 : II(d ? d->getIdentifier() : 0), S(s) {} 466 467 ObjCSummaryKey(Selector s) 468 : II(0), S(s) {} 469 470 IdentifierInfo *getIdentifier() const { return II; } 471 Selector getSelector() const { return S; } 472 }; 473 } 474 475 namespace llvm { 476 template <> struct DenseMapInfo<ObjCSummaryKey> { 477 static inline ObjCSummaryKey getEmptyKey() { 478 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 479 DenseMapInfo<Selector>::getEmptyKey()); 480 } 481 482 static inline ObjCSummaryKey getTombstoneKey() { 483 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 484 DenseMapInfo<Selector>::getTombstoneKey()); 485 } 486 487 static unsigned getHashValue(const ObjCSummaryKey &V) { 488 typedef std::pair<IdentifierInfo*, Selector> PairTy; 489 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 490 V.getSelector())); 491 } 492 493 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 494 return LHS.getIdentifier() == RHS.getIdentifier() && 495 LHS.getSelector() == RHS.getSelector(); 496 } 497 498 }; 499 template <> 500 struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 501 } // end llvm namespace 502 503 namespace { 504 class ObjCSummaryCache { 505 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 506 MapTy M; 507 public: 508 ObjCSummaryCache() {} 509 510 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 511 // Do a lookup with the (D,S) pair. If we find a match return 512 // the iterator. 513 ObjCSummaryKey K(D, S); 514 MapTy::iterator I = M.find(K); 515 516 if (I != M.end()) 517 return I->second; 518 if (!D) 519 return NULL; 520 521 // Walk the super chain. If we find a hit with a parent, we'll end 522 // up returning that summary. We actually allow that key (null,S), as 523 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 524 // generate initial summaries without having to worry about NSObject 525 // being declared. 526 // FIXME: We may change this at some point. 527 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 528 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 529 break; 530 531 if (!C) 532 return NULL; 533 } 534 535 // Cache the summary with original key to make the next lookup faster 536 // and return the iterator. 537 const RetainSummary *Summ = I->second; 538 M[K] = Summ; 539 return Summ; 540 } 541 542 const RetainSummary *find(IdentifierInfo* II, Selector S) { 543 // FIXME: Class method lookup. Right now we dont' have a good way 544 // of going between IdentifierInfo* and the class hierarchy. 545 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 546 547 if (I == M.end()) 548 I = M.find(ObjCSummaryKey(S)); 549 550 return I == M.end() ? NULL : I->second; 551 } 552 553 const RetainSummary *& operator[](ObjCSummaryKey K) { 554 return M[K]; 555 } 556 557 const RetainSummary *& operator[](Selector S) { 558 return M[ ObjCSummaryKey(S) ]; 559 } 560 }; 561 } // end anonymous namespace 562 563 //===----------------------------------------------------------------------===// 564 // Data structures for managing collections of summaries. 565 //===----------------------------------------------------------------------===// 566 567 namespace { 568 class RetainSummaryManager { 569 570 //==-----------------------------------------------------------------==// 571 // Typedefs. 572 //==-----------------------------------------------------------------==// 573 574 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 575 FuncSummariesTy; 576 577 typedef ObjCSummaryCache ObjCMethodSummariesTy; 578 579 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 580 581 //==-----------------------------------------------------------------==// 582 // Data. 583 //==-----------------------------------------------------------------==// 584 585 /// Ctx - The ASTContext object for the analyzed ASTs. 586 ASTContext &Ctx; 587 588 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 589 const bool GCEnabled; 590 591 /// Records whether or not the analyzed code runs in ARC mode. 592 const bool ARCEnabled; 593 594 /// FuncSummaries - A map from FunctionDecls to summaries. 595 FuncSummariesTy FuncSummaries; 596 597 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 598 /// to summaries. 599 ObjCMethodSummariesTy ObjCClassMethodSummaries; 600 601 /// ObjCMethodSummaries - A map from selectors to summaries. 602 ObjCMethodSummariesTy ObjCMethodSummaries; 603 604 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 605 /// and all other data used by the checker. 606 llvm::BumpPtrAllocator BPAlloc; 607 608 /// AF - A factory for ArgEffects objects. 609 ArgEffects::Factory AF; 610 611 /// ScratchArgs - A holding buffer for construct ArgEffects. 612 ArgEffects ScratchArgs; 613 614 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 615 /// objects. 616 RetEffect ObjCAllocRetE; 617 618 /// ObjCInitRetE - Default return effect for init methods returning 619 /// Objective-C objects. 620 RetEffect ObjCInitRetE; 621 622 /// SimpleSummaries - Used for uniquing summaries that don't have special 623 /// effects. 624 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 625 626 //==-----------------------------------------------------------------==// 627 // Methods. 628 //==-----------------------------------------------------------------==// 629 630 /// getArgEffects - Returns a persistent ArgEffects object based on the 631 /// data in ScratchArgs. 632 ArgEffects getArgEffects(); 633 634 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 635 636 const RetainSummary *getUnarySummary(const FunctionType* FT, 637 UnaryFuncKind func); 638 639 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 640 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 641 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 642 643 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 644 645 const RetainSummary *getPersistentSummary(RetEffect RetEff, 646 ArgEffect ReceiverEff = DoNothing, 647 ArgEffect DefaultEff = MayEscape) { 648 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 649 return getPersistentSummary(Summ); 650 } 651 652 const RetainSummary *getDoNothingSummary() { 653 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 654 } 655 656 const RetainSummary *getDefaultSummary() { 657 return getPersistentSummary(RetEffect::MakeNoRet(), 658 DoNothing, MayEscape); 659 } 660 661 const RetainSummary *getPersistentStopSummary() { 662 return getPersistentSummary(RetEffect::MakeNoRet(), 663 StopTracking, StopTracking); 664 } 665 666 void InitializeClassMethodSummaries(); 667 void InitializeMethodSummaries(); 668 private: 669 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 670 ObjCClassMethodSummaries[S] = Summ; 671 } 672 673 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 674 ObjCMethodSummaries[S] = Summ; 675 } 676 677 void addClassMethSummary(const char* Cls, const char* name, 678 const RetainSummary *Summ, bool isNullary = true) { 679 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 680 Selector S = isNullary ? GetNullarySelector(name, Ctx) 681 : GetUnarySelector(name, Ctx); 682 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 683 } 684 685 void addInstMethSummary(const char* Cls, const char* nullaryName, 686 const RetainSummary *Summ) { 687 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 688 Selector S = GetNullarySelector(nullaryName, Ctx); 689 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 690 } 691 692 Selector generateSelector(va_list argp) { 693 SmallVector<IdentifierInfo*, 10> II; 694 695 while (const char* s = va_arg(argp, const char*)) 696 II.push_back(&Ctx.Idents.get(s)); 697 698 return Ctx.Selectors.getSelector(II.size(), &II[0]); 699 } 700 701 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 702 const RetainSummary * Summ, va_list argp) { 703 Selector S = generateSelector(argp); 704 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 705 } 706 707 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 708 va_list argp; 709 va_start(argp, Summ); 710 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 711 va_end(argp); 712 } 713 714 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 715 va_list argp; 716 va_start(argp, Summ); 717 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 718 va_end(argp); 719 } 720 721 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 722 va_list argp; 723 va_start(argp, Summ); 724 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 725 va_end(argp); 726 } 727 728 public: 729 730 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 731 : Ctx(ctx), 732 GCEnabled(gcenabled), 733 ARCEnabled(usesARC), 734 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 735 ObjCAllocRetE(gcenabled 736 ? RetEffect::MakeGCNotOwned() 737 : (usesARC ? RetEffect::MakeARCNotOwned() 738 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 739 ObjCInitRetE(gcenabled 740 ? RetEffect::MakeGCNotOwned() 741 : (usesARC ? RetEffect::MakeARCNotOwned() 742 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 743 InitializeClassMethodSummaries(); 744 InitializeMethodSummaries(); 745 } 746 747 const RetainSummary *getSummary(const CallEvent &Call, 748 ProgramStateRef State = 0); 749 750 const RetainSummary *getFunctionSummary(const FunctionDecl *FD); 751 752 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 753 const ObjCMethodDecl *MD, 754 QualType RetTy, 755 ObjCMethodSummariesTy &CachedSummaries); 756 757 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M, 758 ProgramStateRef State); 759 760 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) { 761 assert(!M.isInstanceMessage()); 762 const ObjCInterfaceDecl *Class = M.getReceiverInterface(); 763 764 return getMethodSummary(M.getSelector(), Class, M.getDecl(), 765 M.getResultType(), ObjCClassMethodSummaries); 766 } 767 768 /// getMethodSummary - This version of getMethodSummary is used to query 769 /// the summary for the current method being analyzed. 770 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 771 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 772 Selector S = MD->getSelector(); 773 QualType ResultTy = MD->getResultType(); 774 775 ObjCMethodSummariesTy *CachedSummaries; 776 if (MD->isInstanceMethod()) 777 CachedSummaries = &ObjCMethodSummaries; 778 else 779 CachedSummaries = &ObjCClassMethodSummaries; 780 781 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries); 782 } 783 784 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, 785 Selector S, QualType RetTy); 786 787 /// Determine if there is a special return effect for this function or method. 788 Optional<RetEffect> getRetEffectFromAnnotations(QualType RetTy, 789 const Decl *D); 790 791 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 792 const ObjCMethodDecl *MD); 793 794 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 795 const FunctionDecl *FD); 796 797 void updateSummaryForCall(const RetainSummary *&Summ, 798 const CallEvent &Call); 799 800 bool isGCEnabled() const { return GCEnabled; } 801 802 bool isARCEnabled() const { return ARCEnabled; } 803 804 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 805 806 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 807 808 friend class RetainSummaryTemplate; 809 }; 810 811 // Used to avoid allocating long-term (BPAlloc'd) memory for default retain 812 // summaries. If a function or method looks like it has a default summary, but 813 // it has annotations, the annotations are added to the stack-based template 814 // and then copied into managed memory. 815 class RetainSummaryTemplate { 816 RetainSummaryManager &Manager; 817 const RetainSummary *&RealSummary; 818 RetainSummary ScratchSummary; 819 bool Accessed; 820 public: 821 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr) 822 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {} 823 824 ~RetainSummaryTemplate() { 825 if (Accessed) 826 RealSummary = Manager.getPersistentSummary(ScratchSummary); 827 } 828 829 RetainSummary &operator*() { 830 Accessed = true; 831 return ScratchSummary; 832 } 833 834 RetainSummary *operator->() { 835 Accessed = true; 836 return &ScratchSummary; 837 } 838 }; 839 840 } // end anonymous namespace 841 842 //===----------------------------------------------------------------------===// 843 // Implementation of checker data structures. 844 //===----------------------------------------------------------------------===// 845 846 ArgEffects RetainSummaryManager::getArgEffects() { 847 ArgEffects AE = ScratchArgs; 848 ScratchArgs = AF.getEmptyMap(); 849 return AE; 850 } 851 852 const RetainSummary * 853 RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 854 // Unique "simple" summaries -- those without ArgEffects. 855 if (OldSumm.isSimple()) { 856 llvm::FoldingSetNodeID ID; 857 OldSumm.Profile(ID); 858 859 void *Pos; 860 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 861 862 if (!N) { 863 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 864 new (N) CachedSummaryNode(OldSumm); 865 SimpleSummaries.InsertNode(N, Pos); 866 } 867 868 return &N->getValue(); 869 } 870 871 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 872 new (Summ) RetainSummary(OldSumm); 873 return Summ; 874 } 875 876 //===----------------------------------------------------------------------===// 877 // Summary creation for functions (largely uses of Core Foundation). 878 //===----------------------------------------------------------------------===// 879 880 static bool isRetain(const FunctionDecl *FD, StringRef FName) { 881 return FName.endswith("Retain"); 882 } 883 884 static bool isRelease(const FunctionDecl *FD, StringRef FName) { 885 return FName.endswith("Release"); 886 } 887 888 static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 889 // FIXME: Remove FunctionDecl parameter. 890 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 891 return FName.find("MakeCollectable") != StringRef::npos; 892 } 893 894 static ArgEffect getStopTrackingHardEquivalent(ArgEffect E) { 895 switch (E) { 896 case DoNothing: 897 case Autorelease: 898 case DecRefBridgedTransfered: 899 case IncRef: 900 case IncRefMsg: 901 case MakeCollectable: 902 case MayEscape: 903 case StopTracking: 904 case StopTrackingHard: 905 return StopTrackingHard; 906 case DecRef: 907 case DecRefAndStopTrackingHard: 908 return DecRefAndStopTrackingHard; 909 case DecRefMsg: 910 case DecRefMsgAndStopTrackingHard: 911 return DecRefMsgAndStopTrackingHard; 912 case Dealloc: 913 return Dealloc; 914 } 915 916 llvm_unreachable("Unknown ArgEffect kind"); 917 } 918 919 void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S, 920 const CallEvent &Call) { 921 if (Call.hasNonZeroCallbackArg()) { 922 ArgEffect RecEffect = 923 getStopTrackingHardEquivalent(S->getReceiverEffect()); 924 ArgEffect DefEffect = 925 getStopTrackingHardEquivalent(S->getDefaultArgEffect()); 926 927 ArgEffects CustomArgEffects = S->getArgEffects(); 928 for (ArgEffects::iterator I = CustomArgEffects.begin(), 929 E = CustomArgEffects.end(); 930 I != E; ++I) { 931 ArgEffect Translated = getStopTrackingHardEquivalent(I->second); 932 if (Translated != DefEffect) 933 ScratchArgs = AF.add(ScratchArgs, I->first, Translated); 934 } 935 936 RetEffect RE = RetEffect::MakeNoRetHard(); 937 938 // Special cases where the callback argument CANNOT free the return value. 939 // This can generally only happen if we know that the callback will only be 940 // called when the return value is already being deallocated. 941 if (const FunctionCall *FC = dyn_cast<FunctionCall>(&Call)) { 942 if (IdentifierInfo *Name = FC->getDecl()->getIdentifier()) { 943 // When the CGBitmapContext is deallocated, the callback here will free 944 // the associated data buffer. 945 if (Name->isStr("CGBitmapContextCreateWithData")) 946 RE = S->getRetEffect(); 947 } 948 } 949 950 S = getPersistentSummary(RE, RecEffect, DefEffect); 951 } 952 953 // Special case '[super init];' and '[self init];' 954 // 955 // Even though calling '[super init]' without assigning the result to self 956 // and checking if the parent returns 'nil' is a bad pattern, it is common. 957 // Additionally, our Self Init checker already warns about it. To avoid 958 // overwhelming the user with messages from both checkers, we model the case 959 // of '[super init]' in cases when it is not consumed by another expression 960 // as if the call preserves the value of 'self'; essentially, assuming it can 961 // never fail and return 'nil'. 962 // Note, we don't want to just stop tracking the value since we want the 963 // RetainCount checker to report leaks and use-after-free if SelfInit checker 964 // is turned off. 965 if (const ObjCMethodCall *MC = dyn_cast<ObjCMethodCall>(&Call)) { 966 if (MC->getMethodFamily() == OMF_init && MC->isReceiverSelfOrSuper()) { 967 968 // Check if the message is not consumed, we know it will not be used in 969 // an assignment, ex: "self = [super init]". 970 const Expr *ME = MC->getOriginExpr(); 971 const LocationContext *LCtx = MC->getLocationContext(); 972 ParentMap &PM = LCtx->getAnalysisDeclContext()->getParentMap(); 973 if (!PM.isConsumedExpr(ME)) { 974 RetainSummaryTemplate ModifiableSummaryTemplate(S, *this); 975 ModifiableSummaryTemplate->setReceiverEffect(DoNothing); 976 ModifiableSummaryTemplate->setRetEffect(RetEffect::MakeNoRet()); 977 } 978 } 979 980 } 981 } 982 983 const RetainSummary * 984 RetainSummaryManager::getSummary(const CallEvent &Call, 985 ProgramStateRef State) { 986 const RetainSummary *Summ; 987 switch (Call.getKind()) { 988 case CE_Function: 989 Summ = getFunctionSummary(cast<FunctionCall>(Call).getDecl()); 990 break; 991 case CE_CXXMember: 992 case CE_CXXMemberOperator: 993 case CE_Block: 994 case CE_CXXConstructor: 995 case CE_CXXDestructor: 996 case CE_CXXAllocator: 997 // FIXME: These calls are currently unsupported. 998 return getPersistentStopSummary(); 999 case CE_ObjCMessage: { 1000 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); 1001 if (Msg.isInstanceMessage()) 1002 Summ = getInstanceMethodSummary(Msg, State); 1003 else 1004 Summ = getClassMethodSummary(Msg); 1005 break; 1006 } 1007 } 1008 1009 updateSummaryForCall(Summ, Call); 1010 1011 assert(Summ && "Unknown call type?"); 1012 return Summ; 1013 } 1014 1015 const RetainSummary * 1016 RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) { 1017 // If we don't know what function we're calling, use our default summary. 1018 if (!FD) 1019 return getDefaultSummary(); 1020 1021 // Look up a summary in our cache of FunctionDecls -> Summaries. 1022 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 1023 if (I != FuncSummaries.end()) 1024 return I->second; 1025 1026 // No summary? Generate one. 1027 const RetainSummary *S = 0; 1028 bool AllowAnnotations = true; 1029 1030 do { 1031 // We generate "stop" summaries for implicitly defined functions. 1032 if (FD->isImplicit()) { 1033 S = getPersistentStopSummary(); 1034 break; 1035 } 1036 1037 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 1038 // function's type. 1039 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 1040 const IdentifierInfo *II = FD->getIdentifier(); 1041 if (!II) 1042 break; 1043 1044 StringRef FName = II->getName(); 1045 1046 // Strip away preceding '_'. Doing this here will effect all the checks 1047 // down below. 1048 FName = FName.substr(FName.find_first_not_of('_')); 1049 1050 // Inspect the result type. 1051 QualType RetTy = FT->getResultType(); 1052 1053 // FIXME: This should all be refactored into a chain of "summary lookup" 1054 // filters. 1055 assert(ScratchArgs.isEmpty()); 1056 1057 if (FName == "pthread_create" || FName == "pthread_setspecific") { 1058 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 1059 // This will be addressed better with IPA. 1060 S = getPersistentStopSummary(); 1061 } else if (FName == "NSMakeCollectable") { 1062 // Handle: id NSMakeCollectable(CFTypeRef) 1063 S = (RetTy->isObjCIdType()) 1064 ? getUnarySummary(FT, cfmakecollectable) 1065 : getPersistentStopSummary(); 1066 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained, 1067 // but we can fully model NSMakeCollectable ourselves. 1068 AllowAnnotations = false; 1069 } else if (FName == "CFPlugInInstanceCreate") { 1070 S = getPersistentSummary(RetEffect::MakeNoRet()); 1071 } else if (FName == "IOBSDNameMatching" || 1072 FName == "IOServiceMatching" || 1073 FName == "IOServiceNameMatching" || 1074 FName == "IORegistryEntrySearchCFProperty" || 1075 FName == "IORegistryEntryIDMatching" || 1076 FName == "IOOpenFirmwarePathMatching") { 1077 // Part of <rdar://problem/6961230>. (IOKit) 1078 // This should be addressed using a API table. 1079 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1080 DoNothing, DoNothing); 1081 } else if (FName == "IOServiceGetMatchingService" || 1082 FName == "IOServiceGetMatchingServices") { 1083 // FIXES: <rdar://problem/6326900> 1084 // This should be addressed using a API table. This strcmp is also 1085 // a little gross, but there is no need to super optimize here. 1086 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 1087 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1088 } else if (FName == "IOServiceAddNotification" || 1089 FName == "IOServiceAddMatchingNotification") { 1090 // Part of <rdar://problem/6961230>. (IOKit) 1091 // This should be addressed using a API table. 1092 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 1093 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1094 } else if (FName == "CVPixelBufferCreateWithBytes") { 1095 // FIXES: <rdar://problem/7283567> 1096 // Eventually this can be improved by recognizing that the pixel 1097 // buffer passed to CVPixelBufferCreateWithBytes is released via 1098 // a callback and doing full IPA to make sure this is done correctly. 1099 // FIXME: This function has an out parameter that returns an 1100 // allocated object. 1101 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 1102 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1103 } else if (FName == "CGBitmapContextCreateWithData") { 1104 // FIXES: <rdar://problem/7358899> 1105 // Eventually this can be improved by recognizing that 'releaseInfo' 1106 // passed to CGBitmapContextCreateWithData is released via 1107 // a callback and doing full IPA to make sure this is done correctly. 1108 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 1109 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1110 DoNothing, DoNothing); 1111 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 1112 // FIXES: <rdar://problem/7283567> 1113 // Eventually this can be improved by recognizing that the pixel 1114 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 1115 // via a callback and doing full IPA to make sure this is done 1116 // correctly. 1117 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 1118 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1119 } else if (FName == "dispatch_set_context" || 1120 FName == "xpc_connection_set_context") { 1121 // <rdar://problem/11059275> - The analyzer currently doesn't have 1122 // a good way to reason about the finalizer function for libdispatch. 1123 // If we pass a context object that is memory managed, stop tracking it. 1124 // <rdar://problem/13783514> - Same problem, but for XPC. 1125 // FIXME: this hack should possibly go away once we can handle 1126 // libdispatch and XPC finalizers. 1127 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1128 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1129 } else if (FName.startswith("NSLog")) { 1130 S = getDoNothingSummary(); 1131 } else if (FName.startswith("NS") && 1132 (FName.find("Insert") != StringRef::npos)) { 1133 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1134 // be deallocated by NSMapRemove. (radar://11152419) 1135 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1136 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1137 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1138 } 1139 1140 // Did we get a summary? 1141 if (S) 1142 break; 1143 1144 if (RetTy->isPointerType()) { 1145 // For CoreFoundation ('CF') types. 1146 if (cocoa::isRefType(RetTy, "CF", FName)) { 1147 if (isRetain(FD, FName)) 1148 S = getUnarySummary(FT, cfretain); 1149 else if (isMakeCollectable(FD, FName)) 1150 S = getUnarySummary(FT, cfmakecollectable); 1151 else 1152 S = getCFCreateGetRuleSummary(FD); 1153 1154 break; 1155 } 1156 1157 // For CoreGraphics ('CG') types. 1158 if (cocoa::isRefType(RetTy, "CG", FName)) { 1159 if (isRetain(FD, FName)) 1160 S = getUnarySummary(FT, cfretain); 1161 else 1162 S = getCFCreateGetRuleSummary(FD); 1163 1164 break; 1165 } 1166 1167 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1168 if (cocoa::isRefType(RetTy, "DADisk") || 1169 cocoa::isRefType(RetTy, "DADissenter") || 1170 cocoa::isRefType(RetTy, "DASessionRef")) { 1171 S = getCFCreateGetRuleSummary(FD); 1172 break; 1173 } 1174 1175 if (FD->getAttr<CFAuditedTransferAttr>()) { 1176 S = getCFCreateGetRuleSummary(FD); 1177 break; 1178 } 1179 1180 break; 1181 } 1182 1183 // Check for release functions, the only kind of functions that we care 1184 // about that don't return a pointer type. 1185 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1186 // Test for 'CGCF'. 1187 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1188 1189 if (isRelease(FD, FName)) 1190 S = getUnarySummary(FT, cfrelease); 1191 else { 1192 assert (ScratchArgs.isEmpty()); 1193 // Remaining CoreFoundation and CoreGraphics functions. 1194 // We use to assume that they all strictly followed the ownership idiom 1195 // and that ownership cannot be transferred. While this is technically 1196 // correct, many methods allow a tracked object to escape. For example: 1197 // 1198 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1199 // CFDictionaryAddValue(y, key, x); 1200 // CFRelease(x); 1201 // ... it is okay to use 'x' since 'y' has a reference to it 1202 // 1203 // We handle this and similar cases with the follow heuristic. If the 1204 // function name contains "InsertValue", "SetValue", "AddValue", 1205 // "AppendValue", or "SetAttribute", then we assume that arguments may 1206 // "escape." This means that something else holds on to the object, 1207 // allowing it be used even after its local retain count drops to 0. 1208 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1209 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1210 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1211 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1212 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1213 ? MayEscape : DoNothing; 1214 1215 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1216 } 1217 } 1218 } 1219 while (0); 1220 1221 // If we got all the way here without any luck, use a default summary. 1222 if (!S) 1223 S = getDefaultSummary(); 1224 1225 // Annotations override defaults. 1226 if (AllowAnnotations) 1227 updateSummaryFromAnnotations(S, FD); 1228 1229 FuncSummaries[FD] = S; 1230 return S; 1231 } 1232 1233 const RetainSummary * 1234 RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1235 if (coreFoundation::followsCreateRule(FD)) 1236 return getCFSummaryCreateRule(FD); 1237 1238 return getCFSummaryGetRule(FD); 1239 } 1240 1241 const RetainSummary * 1242 RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1243 UnaryFuncKind func) { 1244 1245 // Sanity check that this is *really* a unary function. This can 1246 // happen if people do weird things. 1247 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1248 if (!FTP || FTP->getNumArgs() != 1) 1249 return getPersistentStopSummary(); 1250 1251 assert (ScratchArgs.isEmpty()); 1252 1253 ArgEffect Effect; 1254 switch (func) { 1255 case cfretain: Effect = IncRef; break; 1256 case cfrelease: Effect = DecRef; break; 1257 case cfmakecollectable: Effect = MakeCollectable; break; 1258 } 1259 1260 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1261 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1262 } 1263 1264 const RetainSummary * 1265 RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1266 assert (ScratchArgs.isEmpty()); 1267 1268 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1269 } 1270 1271 const RetainSummary * 1272 RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1273 assert (ScratchArgs.isEmpty()); 1274 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1275 DoNothing, DoNothing); 1276 } 1277 1278 //===----------------------------------------------------------------------===// 1279 // Summary creation for Selectors. 1280 //===----------------------------------------------------------------------===// 1281 1282 Optional<RetEffect> 1283 RetainSummaryManager::getRetEffectFromAnnotations(QualType RetTy, 1284 const Decl *D) { 1285 if (cocoa::isCocoaObjectRef(RetTy)) { 1286 if (D->getAttr<NSReturnsRetainedAttr>()) 1287 return ObjCAllocRetE; 1288 1289 if (D->getAttr<NSReturnsNotRetainedAttr>() || 1290 D->getAttr<NSReturnsAutoreleasedAttr>()) 1291 return RetEffect::MakeNotOwned(RetEffect::ObjC); 1292 1293 } else if (!RetTy->isPointerType()) { 1294 return None; 1295 } 1296 1297 if (D->getAttr<CFReturnsRetainedAttr>()) 1298 return RetEffect::MakeOwned(RetEffect::CF, true); 1299 1300 if (D->getAttr<CFReturnsNotRetainedAttr>()) 1301 return RetEffect::MakeNotOwned(RetEffect::CF); 1302 1303 return None; 1304 } 1305 1306 void 1307 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1308 const FunctionDecl *FD) { 1309 if (!FD) 1310 return; 1311 1312 assert(Summ && "Must have a summary to add annotations to."); 1313 RetainSummaryTemplate Template(Summ, *this); 1314 1315 // Effects on the parameters. 1316 unsigned parm_idx = 0; 1317 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1318 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1319 const ParmVarDecl *pd = *pi; 1320 if (pd->getAttr<NSConsumedAttr>()) 1321 Template->addArg(AF, parm_idx, DecRefMsg); 1322 else if (pd->getAttr<CFConsumedAttr>()) 1323 Template->addArg(AF, parm_idx, DecRef); 1324 } 1325 1326 QualType RetTy = FD->getResultType(); 1327 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, FD)) 1328 Template->setRetEffect(*RetE); 1329 } 1330 1331 void 1332 RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1333 const ObjCMethodDecl *MD) { 1334 if (!MD) 1335 return; 1336 1337 assert(Summ && "Must have a valid summary to add annotations to"); 1338 RetainSummaryTemplate Template(Summ, *this); 1339 1340 // Effects on the receiver. 1341 if (MD->getAttr<NSConsumesSelfAttr>()) 1342 Template->setReceiverEffect(DecRefMsg); 1343 1344 // Effects on the parameters. 1345 unsigned parm_idx = 0; 1346 for (ObjCMethodDecl::param_const_iterator 1347 pi=MD->param_begin(), pe=MD->param_end(); 1348 pi != pe; ++pi, ++parm_idx) { 1349 const ParmVarDecl *pd = *pi; 1350 if (pd->getAttr<NSConsumedAttr>()) 1351 Template->addArg(AF, parm_idx, DecRefMsg); 1352 else if (pd->getAttr<CFConsumedAttr>()) { 1353 Template->addArg(AF, parm_idx, DecRef); 1354 } 1355 } 1356 1357 QualType RetTy = MD->getResultType(); 1358 if (Optional<RetEffect> RetE = getRetEffectFromAnnotations(RetTy, MD)) 1359 Template->setRetEffect(*RetE); 1360 } 1361 1362 const RetainSummary * 1363 RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1364 Selector S, QualType RetTy) { 1365 // Any special effects? 1366 ArgEffect ReceiverEff = DoNothing; 1367 RetEffect ResultEff = RetEffect::MakeNoRet(); 1368 1369 // Check the method family, and apply any default annotations. 1370 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1371 case OMF_None: 1372 case OMF_performSelector: 1373 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1374 // FIXME: Does the non-threaded performSelector family really belong here? 1375 // The selector could be, say, @selector(copy). 1376 if (cocoa::isCocoaObjectRef(RetTy)) 1377 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1378 else if (coreFoundation::isCFObjectRef(RetTy)) { 1379 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1380 // values for alloc, new, copy, or mutableCopy, so we have to 1381 // double-check with the selector. This is ugly, but there aren't that 1382 // many Objective-C methods that return CF objects, right? 1383 if (MD) { 1384 switch (S.getMethodFamily()) { 1385 case OMF_alloc: 1386 case OMF_new: 1387 case OMF_copy: 1388 case OMF_mutableCopy: 1389 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1390 break; 1391 default: 1392 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1393 break; 1394 } 1395 } else { 1396 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1397 } 1398 } 1399 break; 1400 case OMF_init: 1401 ResultEff = ObjCInitRetE; 1402 ReceiverEff = DecRefMsg; 1403 break; 1404 case OMF_alloc: 1405 case OMF_new: 1406 case OMF_copy: 1407 case OMF_mutableCopy: 1408 if (cocoa::isCocoaObjectRef(RetTy)) 1409 ResultEff = ObjCAllocRetE; 1410 else if (coreFoundation::isCFObjectRef(RetTy)) 1411 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1412 break; 1413 case OMF_autorelease: 1414 ReceiverEff = Autorelease; 1415 break; 1416 case OMF_retain: 1417 ReceiverEff = IncRefMsg; 1418 break; 1419 case OMF_release: 1420 ReceiverEff = DecRefMsg; 1421 break; 1422 case OMF_dealloc: 1423 ReceiverEff = Dealloc; 1424 break; 1425 case OMF_self: 1426 // -self is handled specially by the ExprEngine to propagate the receiver. 1427 break; 1428 case OMF_retainCount: 1429 case OMF_finalize: 1430 // These methods don't return objects. 1431 break; 1432 } 1433 1434 // If one of the arguments in the selector has the keyword 'delegate' we 1435 // should stop tracking the reference count for the receiver. This is 1436 // because the reference count is quite possibly handled by a delegate 1437 // method. 1438 if (S.isKeywordSelector()) { 1439 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { 1440 StringRef Slot = S.getNameForSlot(i); 1441 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { 1442 if (ResultEff == ObjCInitRetE) 1443 ResultEff = RetEffect::MakeNoRetHard(); 1444 else 1445 ReceiverEff = StopTrackingHard; 1446 } 1447 } 1448 } 1449 1450 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1451 ResultEff.getKind() == RetEffect::NoRet) 1452 return getDefaultSummary(); 1453 1454 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1455 } 1456 1457 const RetainSummary * 1458 RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg, 1459 ProgramStateRef State) { 1460 const ObjCInterfaceDecl *ReceiverClass = 0; 1461 1462 // We do better tracking of the type of the object than the core ExprEngine. 1463 // See if we have its type in our private state. 1464 // FIXME: Eventually replace the use of state->get<RefBindings> with 1465 // a generic API for reasoning about the Objective-C types of symbolic 1466 // objects. 1467 SVal ReceiverV = Msg.getReceiverSVal(); 1468 if (SymbolRef Sym = ReceiverV.getAsLocSymbol()) 1469 if (const RefVal *T = getRefBinding(State, Sym)) 1470 if (const ObjCObjectPointerType *PT = 1471 T->getType()->getAs<ObjCObjectPointerType>()) 1472 ReceiverClass = PT->getInterfaceDecl(); 1473 1474 // If we don't know what kind of object this is, fall back to its static type. 1475 if (!ReceiverClass) 1476 ReceiverClass = Msg.getReceiverInterface(); 1477 1478 // FIXME: The receiver could be a reference to a class, meaning that 1479 // we should use the class method. 1480 // id x = [NSObject class]; 1481 // [x performSelector:... withObject:... afterDelay:...]; 1482 Selector S = Msg.getSelector(); 1483 const ObjCMethodDecl *Method = Msg.getDecl(); 1484 if (!Method && ReceiverClass) 1485 Method = ReceiverClass->getInstanceMethod(S); 1486 1487 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(), 1488 ObjCMethodSummaries); 1489 } 1490 1491 const RetainSummary * 1492 RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 1493 const ObjCMethodDecl *MD, QualType RetTy, 1494 ObjCMethodSummariesTy &CachedSummaries) { 1495 1496 // Look up a summary in our summary cache. 1497 const RetainSummary *Summ = CachedSummaries.find(ID, S); 1498 1499 if (!Summ) { 1500 Summ = getStandardMethodSummary(MD, S, RetTy); 1501 1502 // Annotations override defaults. 1503 updateSummaryFromAnnotations(Summ, MD); 1504 1505 // Memoize the summary. 1506 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ; 1507 } 1508 1509 return Summ; 1510 } 1511 1512 void RetainSummaryManager::InitializeClassMethodSummaries() { 1513 assert(ScratchArgs.isEmpty()); 1514 // Create the [NSAssertionHandler currentHander] summary. 1515 addClassMethSummary("NSAssertionHandler", "currentHandler", 1516 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1517 1518 // Create the [NSAutoreleasePool addObject:] summary. 1519 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1520 addClassMethSummary("NSAutoreleasePool", "addObject", 1521 getPersistentSummary(RetEffect::MakeNoRet(), 1522 DoNothing, Autorelease)); 1523 } 1524 1525 void RetainSummaryManager::InitializeMethodSummaries() { 1526 1527 assert (ScratchArgs.isEmpty()); 1528 1529 // Create the "init" selector. It just acts as a pass-through for the 1530 // receiver. 1531 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1532 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1533 1534 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1535 // claims the receiver and returns a retained object. 1536 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1537 InitSumm); 1538 1539 // The next methods are allocators. 1540 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1541 const RetainSummary *CFAllocSumm = 1542 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1543 1544 // Create the "retain" selector. 1545 RetEffect NoRet = RetEffect::MakeNoRet(); 1546 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1547 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1548 1549 // Create the "release" selector. 1550 Summ = getPersistentSummary(NoRet, DecRefMsg); 1551 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1552 1553 // Create the -dealloc summary. 1554 Summ = getPersistentSummary(NoRet, Dealloc); 1555 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1556 1557 // Create the "autorelease" selector. 1558 Summ = getPersistentSummary(NoRet, Autorelease); 1559 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1560 1561 // For NSWindow, allocated objects are (initially) self-owned. 1562 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1563 // self-own themselves. However, they only do this once they are displayed. 1564 // Thus, we need to track an NSWindow's display status. 1565 // This is tracked in <rdar://problem/6062711>. 1566 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1567 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1568 StopTracking, 1569 StopTracking); 1570 1571 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1572 1573 // For NSPanel (which subclasses NSWindow), allocated objects are not 1574 // self-owned. 1575 // FIXME: For now we don't track NSPanels. object for the same reason 1576 // as for NSWindow objects. 1577 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1578 1579 // Don't track allocated autorelease pools, as it is okay to prematurely 1580 // exit a method. 1581 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1582 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1583 addClassMethSummary("NSAutoreleasePool", "new", NoTrackYet); 1584 1585 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1586 addInstMethSummary("QCRenderer", AllocSumm, 1587 "createSnapshotImageOfType", NULL); 1588 addInstMethSummary("QCView", AllocSumm, 1589 "createSnapshotImageOfType", NULL); 1590 1591 // Create summaries for CIContext, 'createCGImage' and 1592 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1593 // automatically garbage collected. 1594 addInstMethSummary("CIContext", CFAllocSumm, 1595 "createCGImage", "fromRect", NULL); 1596 addInstMethSummary("CIContext", CFAllocSumm, 1597 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1598 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1599 "info", NULL); 1600 } 1601 1602 //===----------------------------------------------------------------------===// 1603 // Error reporting. 1604 //===----------------------------------------------------------------------===// 1605 namespace { 1606 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1607 SummaryLogTy; 1608 1609 //===-------------===// 1610 // Bug Descriptions. // 1611 //===-------------===// 1612 1613 class CFRefBug : public BugType { 1614 protected: 1615 CFRefBug(StringRef name) 1616 : BugType(name, categories::MemoryCoreFoundationObjectiveC) {} 1617 public: 1618 1619 // FIXME: Eventually remove. 1620 virtual const char *getDescription() const = 0; 1621 1622 virtual bool isLeak() const { return false; } 1623 }; 1624 1625 class UseAfterRelease : public CFRefBug { 1626 public: 1627 UseAfterRelease() : CFRefBug("Use-after-release") {} 1628 1629 const char *getDescription() const { 1630 return "Reference-counted object is used after it is released"; 1631 } 1632 }; 1633 1634 class BadRelease : public CFRefBug { 1635 public: 1636 BadRelease() : CFRefBug("Bad release") {} 1637 1638 const char *getDescription() const { 1639 return "Incorrect decrement of the reference count of an object that is " 1640 "not owned at this point by the caller"; 1641 } 1642 }; 1643 1644 class DeallocGC : public CFRefBug { 1645 public: 1646 DeallocGC() 1647 : CFRefBug("-dealloc called while using garbage collection") {} 1648 1649 const char *getDescription() const { 1650 return "-dealloc called while using garbage collection"; 1651 } 1652 }; 1653 1654 class DeallocNotOwned : public CFRefBug { 1655 public: 1656 DeallocNotOwned() 1657 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1658 1659 const char *getDescription() const { 1660 return "-dealloc sent to object that may be referenced elsewhere"; 1661 } 1662 }; 1663 1664 class OverAutorelease : public CFRefBug { 1665 public: 1666 OverAutorelease() 1667 : CFRefBug("Object autoreleased too many times") {} 1668 1669 const char *getDescription() const { 1670 return "Object autoreleased too many times"; 1671 } 1672 }; 1673 1674 class ReturnedNotOwnedForOwned : public CFRefBug { 1675 public: 1676 ReturnedNotOwnedForOwned() 1677 : CFRefBug("Method should return an owned object") {} 1678 1679 const char *getDescription() const { 1680 return "Object with a +0 retain count returned to caller where a +1 " 1681 "(owning) retain count is expected"; 1682 } 1683 }; 1684 1685 class Leak : public CFRefBug { 1686 public: 1687 Leak(StringRef name) 1688 : CFRefBug(name) { 1689 // Leaks should not be reported if they are post-dominated by a sink. 1690 setSuppressOnSink(true); 1691 } 1692 1693 const char *getDescription() const { return ""; } 1694 1695 bool isLeak() const { return true; } 1696 }; 1697 1698 //===---------===// 1699 // Bug Reports. // 1700 //===---------===// 1701 1702 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1703 protected: 1704 SymbolRef Sym; 1705 const SummaryLogTy &SummaryLog; 1706 bool GCEnabled; 1707 1708 public: 1709 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1710 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1711 1712 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1713 static int x = 0; 1714 ID.AddPointer(&x); 1715 ID.AddPointer(Sym); 1716 } 1717 1718 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1719 const ExplodedNode *PrevN, 1720 BugReporterContext &BRC, 1721 BugReport &BR); 1722 1723 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1724 const ExplodedNode *N, 1725 BugReport &BR); 1726 }; 1727 1728 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1729 public: 1730 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1731 const SummaryLogTy &log) 1732 : CFRefReportVisitor(sym, GCEnabled, log) {} 1733 1734 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1735 const ExplodedNode *N, 1736 BugReport &BR); 1737 1738 virtual BugReporterVisitor *clone() const { 1739 // The curiously-recurring template pattern only works for one level of 1740 // subclassing. Rather than make a new template base for 1741 // CFRefReportVisitor, we simply override clone() to do the right thing. 1742 // This could be trouble someday if BugReporterVisitorImpl is ever 1743 // used for something else besides a convenient implementation of clone(). 1744 return new CFRefLeakReportVisitor(*this); 1745 } 1746 }; 1747 1748 class CFRefReport : public BugReport { 1749 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1750 1751 public: 1752 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1753 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1754 bool registerVisitor = true) 1755 : BugReport(D, D.getDescription(), n) { 1756 if (registerVisitor) 1757 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1758 addGCModeDescription(LOpts, GCEnabled); 1759 } 1760 1761 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1762 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1763 StringRef endText) 1764 : BugReport(D, D.getDescription(), endText, n) { 1765 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1766 addGCModeDescription(LOpts, GCEnabled); 1767 } 1768 1769 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1770 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1771 if (!BugTy.isLeak()) 1772 return BugReport::getRanges(); 1773 else 1774 return std::make_pair(ranges_iterator(), ranges_iterator()); 1775 } 1776 }; 1777 1778 class CFRefLeakReport : public CFRefReport { 1779 const MemRegion* AllocBinding; 1780 public: 1781 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1782 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1783 CheckerContext &Ctx, 1784 bool IncludeAllocationLine); 1785 1786 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1787 assert(Location.isValid()); 1788 return Location; 1789 } 1790 }; 1791 } // end anonymous namespace 1792 1793 void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1794 bool GCEnabled) { 1795 const char *GCModeDescription = 0; 1796 1797 switch (LOpts.getGC()) { 1798 case LangOptions::GCOnly: 1799 assert(GCEnabled); 1800 GCModeDescription = "Code is compiled to only use garbage collection"; 1801 break; 1802 1803 case LangOptions::NonGC: 1804 assert(!GCEnabled); 1805 GCModeDescription = "Code is compiled to use reference counts"; 1806 break; 1807 1808 case LangOptions::HybridGC: 1809 if (GCEnabled) { 1810 GCModeDescription = "Code is compiled to use either garbage collection " 1811 "(GC) or reference counts (non-GC). The bug occurs " 1812 "with GC enabled"; 1813 break; 1814 } else { 1815 GCModeDescription = "Code is compiled to use either garbage collection " 1816 "(GC) or reference counts (non-GC). The bug occurs " 1817 "in non-GC mode"; 1818 break; 1819 } 1820 } 1821 1822 assert(GCModeDescription && "invalid/unknown GC mode"); 1823 addExtraText(GCModeDescription); 1824 } 1825 1826 // FIXME: This should be a method on SmallVector. 1827 static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1828 ArgEffect X) { 1829 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1830 I!=E; ++I) 1831 if (*I == X) return true; 1832 1833 return false; 1834 } 1835 1836 static bool isNumericLiteralExpression(const Expr *E) { 1837 // FIXME: This set of cases was copied from SemaExprObjC. 1838 return isa<IntegerLiteral>(E) || 1839 isa<CharacterLiteral>(E) || 1840 isa<FloatingLiteral>(E) || 1841 isa<ObjCBoolLiteralExpr>(E) || 1842 isa<CXXBoolLiteralExpr>(E); 1843 } 1844 1845 PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1846 const ExplodedNode *PrevN, 1847 BugReporterContext &BRC, 1848 BugReport &BR) { 1849 // FIXME: We will eventually need to handle non-statement-based events 1850 // (__attribute__((cleanup))). 1851 if (!N->getLocation().getAs<StmtPoint>()) 1852 return NULL; 1853 1854 // Check if the type state has changed. 1855 ProgramStateRef PrevSt = PrevN->getState(); 1856 ProgramStateRef CurrSt = N->getState(); 1857 const LocationContext *LCtx = N->getLocationContext(); 1858 1859 const RefVal* CurrT = getRefBinding(CurrSt, Sym); 1860 if (!CurrT) return NULL; 1861 1862 const RefVal &CurrV = *CurrT; 1863 const RefVal *PrevT = getRefBinding(PrevSt, Sym); 1864 1865 // Create a string buffer to constain all the useful things we want 1866 // to tell the user. 1867 std::string sbuf; 1868 llvm::raw_string_ostream os(sbuf); 1869 1870 // This is the allocation site since the previous node had no bindings 1871 // for this symbol. 1872 if (!PrevT) { 1873 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 1874 1875 if (isa<ObjCArrayLiteral>(S)) { 1876 os << "NSArray literal is an object with a +0 retain count"; 1877 } 1878 else if (isa<ObjCDictionaryLiteral>(S)) { 1879 os << "NSDictionary literal is an object with a +0 retain count"; 1880 } 1881 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1882 if (isNumericLiteralExpression(BL->getSubExpr())) 1883 os << "NSNumber literal is an object with a +0 retain count"; 1884 else { 1885 const ObjCInterfaceDecl *BoxClass = 0; 1886 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1887 BoxClass = Method->getClassInterface(); 1888 1889 // We should always be able to find the boxing class interface, 1890 // but consider this future-proofing. 1891 if (BoxClass) 1892 os << *BoxClass << " b"; 1893 else 1894 os << "B"; 1895 1896 os << "oxed expression produces an object with a +0 retain count"; 1897 } 1898 } 1899 else { 1900 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1901 // Get the name of the callee (if it is available). 1902 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1903 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1904 os << "Call to function '" << *FD << '\''; 1905 else 1906 os << "function call"; 1907 } 1908 else { 1909 assert(isa<ObjCMessageExpr>(S)); 1910 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager(); 1911 CallEventRef<ObjCMethodCall> Call 1912 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx); 1913 1914 switch (Call->getMessageKind()) { 1915 case OCM_Message: 1916 os << "Method"; 1917 break; 1918 case OCM_PropertyAccess: 1919 os << "Property"; 1920 break; 1921 case OCM_Subscript: 1922 os << "Subscript"; 1923 break; 1924 } 1925 } 1926 1927 if (CurrV.getObjKind() == RetEffect::CF) { 1928 os << " returns a Core Foundation object with a "; 1929 } 1930 else { 1931 assert (CurrV.getObjKind() == RetEffect::ObjC); 1932 os << " returns an Objective-C object with a "; 1933 } 1934 1935 if (CurrV.isOwned()) { 1936 os << "+1 retain count"; 1937 1938 if (GCEnabled) { 1939 assert(CurrV.getObjKind() == RetEffect::CF); 1940 os << ". " 1941 "Core Foundation objects are not automatically garbage collected."; 1942 } 1943 } 1944 else { 1945 assert (CurrV.isNotOwned()); 1946 os << "+0 retain count"; 1947 } 1948 } 1949 1950 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1951 N->getLocationContext()); 1952 return new PathDiagnosticEventPiece(Pos, os.str()); 1953 } 1954 1955 // Gather up the effects that were performed on the object at this 1956 // program point 1957 SmallVector<ArgEffect, 2> AEffects; 1958 1959 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1960 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1961 // We only have summaries attached to nodes after evaluating CallExpr and 1962 // ObjCMessageExprs. 1963 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 1964 1965 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1966 // Iterate through the parameter expressions and see if the symbol 1967 // was ever passed as an argument. 1968 unsigned i = 0; 1969 1970 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1971 AI!=AE; ++AI, ++i) { 1972 1973 // Retrieve the value of the argument. Is it the symbol 1974 // we are interested in? 1975 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1976 continue; 1977 1978 // We have an argument. Get the effect! 1979 AEffects.push_back(Summ->getArg(i)); 1980 } 1981 } 1982 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 1983 if (const Expr *receiver = ME->getInstanceReceiver()) 1984 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 1985 .getAsLocSymbol() == Sym) { 1986 // The symbol we are tracking is the receiver. 1987 AEffects.push_back(Summ->getReceiverEffect()); 1988 } 1989 } 1990 } 1991 1992 do { 1993 // Get the previous type state. 1994 RefVal PrevV = *PrevT; 1995 1996 // Specially handle -dealloc. 1997 if (!GCEnabled && contains(AEffects, Dealloc)) { 1998 // Determine if the object's reference count was pushed to zero. 1999 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2000 // We may not have transitioned to 'release' if we hit an error. 2001 // This case is handled elsewhere. 2002 if (CurrV.getKind() == RefVal::Released) { 2003 assert(CurrV.getCombinedCounts() == 0); 2004 os << "Object released by directly sending the '-dealloc' message"; 2005 break; 2006 } 2007 } 2008 2009 // Specially handle CFMakeCollectable and friends. 2010 if (contains(AEffects, MakeCollectable)) { 2011 // Get the name of the function. 2012 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 2013 SVal X = 2014 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2015 const FunctionDecl *FD = X.getAsFunctionDecl(); 2016 2017 if (GCEnabled) { 2018 // Determine if the object's reference count was pushed to zero. 2019 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2020 2021 os << "In GC mode a call to '" << *FD 2022 << "' decrements an object's retain count and registers the " 2023 "object with the garbage collector. "; 2024 2025 if (CurrV.getKind() == RefVal::Released) { 2026 assert(CurrV.getCount() == 0); 2027 os << "Since it now has a 0 retain count the object can be " 2028 "automatically collected by the garbage collector."; 2029 } 2030 else 2031 os << "An object must have a 0 retain count to be garbage collected. " 2032 "After this call its retain count is +" << CurrV.getCount() 2033 << '.'; 2034 } 2035 else 2036 os << "When GC is not enabled a call to '" << *FD 2037 << "' has no effect on its argument."; 2038 2039 // Nothing more to say. 2040 break; 2041 } 2042 2043 // Determine if the typestate has changed. 2044 if (!(PrevV == CurrV)) 2045 switch (CurrV.getKind()) { 2046 case RefVal::Owned: 2047 case RefVal::NotOwned: 2048 2049 if (PrevV.getCount() == CurrV.getCount()) { 2050 // Did an autorelease message get sent? 2051 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2052 return 0; 2053 2054 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2055 os << "Object autoreleased"; 2056 break; 2057 } 2058 2059 if (PrevV.getCount() > CurrV.getCount()) 2060 os << "Reference count decremented."; 2061 else 2062 os << "Reference count incremented."; 2063 2064 if (unsigned Count = CurrV.getCount()) 2065 os << " The object now has a +" << Count << " retain count."; 2066 2067 if (PrevV.getKind() == RefVal::Released) { 2068 assert(GCEnabled && CurrV.getCount() > 0); 2069 os << " The object is not eligible for garbage collection until " 2070 "the retain count reaches 0 again."; 2071 } 2072 2073 break; 2074 2075 case RefVal::Released: 2076 os << "Object released."; 2077 break; 2078 2079 case RefVal::ReturnedOwned: 2080 // Autoreleases can be applied after marking a node ReturnedOwned. 2081 if (CurrV.getAutoreleaseCount()) 2082 return NULL; 2083 2084 os << "Object returned to caller as an owning reference (single " 2085 "retain count transferred to caller)"; 2086 break; 2087 2088 case RefVal::ReturnedNotOwned: 2089 os << "Object returned to caller with a +0 retain count"; 2090 break; 2091 2092 default: 2093 return NULL; 2094 } 2095 2096 // Emit any remaining diagnostics for the argument effects (if any). 2097 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2098 E=AEffects.end(); I != E; ++I) { 2099 2100 // A bunch of things have alternate behavior under GC. 2101 if (GCEnabled) 2102 switch (*I) { 2103 default: break; 2104 case Autorelease: 2105 os << "In GC mode an 'autorelease' has no effect."; 2106 continue; 2107 case IncRefMsg: 2108 os << "In GC mode the 'retain' message has no effect."; 2109 continue; 2110 case DecRefMsg: 2111 os << "In GC mode the 'release' message has no effect."; 2112 continue; 2113 } 2114 } 2115 } while (0); 2116 2117 if (os.str().empty()) 2118 return 0; // We have nothing to say! 2119 2120 const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt(); 2121 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2122 N->getLocationContext()); 2123 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2124 2125 // Add the range by scanning the children of the statement for any bindings 2126 // to Sym. 2127 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2128 I!=E; ++I) 2129 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2130 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2131 P->addRange(Exp->getSourceRange()); 2132 break; 2133 } 2134 2135 return P; 2136 } 2137 2138 // Find the first node in the current function context that referred to the 2139 // tracked symbol and the memory location that value was stored to. Note, the 2140 // value is only reported if the allocation occurred in the same function as 2141 // the leak. The function can also return a location context, which should be 2142 // treated as interesting. 2143 struct AllocationInfo { 2144 const ExplodedNode* N; 2145 const MemRegion *R; 2146 const LocationContext *InterestingMethodContext; 2147 AllocationInfo(const ExplodedNode *InN, 2148 const MemRegion *InR, 2149 const LocationContext *InInterestingMethodContext) : 2150 N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {} 2151 }; 2152 2153 static AllocationInfo 2154 GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2155 SymbolRef Sym) { 2156 const ExplodedNode *AllocationNode = N; 2157 const ExplodedNode *AllocationNodeInCurrentContext = N; 2158 const MemRegion* FirstBinding = 0; 2159 const LocationContext *LeakContext = N->getLocationContext(); 2160 2161 // The location context of the init method called on the leaked object, if 2162 // available. 2163 const LocationContext *InitMethodContext = 0; 2164 2165 while (N) { 2166 ProgramStateRef St = N->getState(); 2167 const LocationContext *NContext = N->getLocationContext(); 2168 2169 if (!getRefBinding(St, Sym)) 2170 break; 2171 2172 StoreManager::FindUniqueBinding FB(Sym); 2173 StateMgr.iterBindings(St, FB); 2174 2175 if (FB) { 2176 const MemRegion *R = FB.getRegion(); 2177 const VarRegion *VR = R->getBaseRegion()->getAs<VarRegion>(); 2178 // Do not show local variables belonging to a function other than 2179 // where the error is reported. 2180 if (!VR || VR->getStackFrame() == LeakContext->getCurrentStackFrame()) 2181 FirstBinding = R; 2182 } 2183 2184 // AllocationNode is the last node in which the symbol was tracked. 2185 AllocationNode = N; 2186 2187 // AllocationNodeInCurrentContext, is the last node in the current context 2188 // in which the symbol was tracked. 2189 if (NContext == LeakContext) 2190 AllocationNodeInCurrentContext = N; 2191 2192 // Find the last init that was called on the given symbol and store the 2193 // init method's location context. 2194 if (!InitMethodContext) 2195 if (Optional<CallEnter> CEP = N->getLocation().getAs<CallEnter>()) { 2196 const Stmt *CE = CEP->getCallExpr(); 2197 if (const ObjCMessageExpr *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) { 2198 const Stmt *RecExpr = ME->getInstanceReceiver(); 2199 if (RecExpr) { 2200 SVal RecV = St->getSVal(RecExpr, NContext); 2201 if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym) 2202 InitMethodContext = CEP->getCalleeContext(); 2203 } 2204 } 2205 } 2206 2207 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2208 } 2209 2210 // If we are reporting a leak of the object that was allocated with alloc, 2211 // mark its init method as interesting. 2212 const LocationContext *InterestingMethodContext = 0; 2213 if (InitMethodContext) { 2214 const ProgramPoint AllocPP = AllocationNode->getLocation(); 2215 if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>()) 2216 if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>()) 2217 if (ME->getMethodFamily() == OMF_alloc) 2218 InterestingMethodContext = InitMethodContext; 2219 } 2220 2221 // If allocation happened in a function different from the leak node context, 2222 // do not report the binding. 2223 assert(N && "Could not find allocation node"); 2224 if (N->getLocationContext() != LeakContext) { 2225 FirstBinding = 0; 2226 } 2227 2228 return AllocationInfo(AllocationNodeInCurrentContext, 2229 FirstBinding, 2230 InterestingMethodContext); 2231 } 2232 2233 PathDiagnosticPiece* 2234 CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2235 const ExplodedNode *EndN, 2236 BugReport &BR) { 2237 BR.markInteresting(Sym); 2238 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2239 } 2240 2241 PathDiagnosticPiece* 2242 CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2243 const ExplodedNode *EndN, 2244 BugReport &BR) { 2245 2246 // Tell the BugReporterContext to report cases when the tracked symbol is 2247 // assigned to different variables, etc. 2248 BR.markInteresting(Sym); 2249 2250 // We are reporting a leak. Walk up the graph to get to the first node where 2251 // the symbol appeared, and also get the first VarDecl that tracked object 2252 // is stored to. 2253 AllocationInfo AllocI = 2254 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2255 2256 const MemRegion* FirstBinding = AllocI.R; 2257 BR.markInteresting(AllocI.InterestingMethodContext); 2258 2259 SourceManager& SM = BRC.getSourceManager(); 2260 2261 // Compute an actual location for the leak. Sometimes a leak doesn't 2262 // occur at an actual statement (e.g., transition between blocks; end 2263 // of function) so we need to walk the graph and compute a real location. 2264 const ExplodedNode *LeakN = EndN; 2265 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2266 2267 std::string sbuf; 2268 llvm::raw_string_ostream os(sbuf); 2269 2270 os << "Object leaked: "; 2271 2272 if (FirstBinding) { 2273 os << "object allocated and stored into '" 2274 << FirstBinding->getString() << '\''; 2275 } 2276 else 2277 os << "allocated object"; 2278 2279 // Get the retain count. 2280 const RefVal* RV = getRefBinding(EndN->getState(), Sym); 2281 assert(RV); 2282 2283 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2284 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2285 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2286 // to the caller for NS objects. 2287 const Decl *D = &EndN->getCodeDecl(); 2288 2289 os << (isa<ObjCMethodDecl>(D) ? " is returned from a method " 2290 : " is returned from a function "); 2291 2292 if (D->getAttr<CFReturnsNotRetainedAttr>()) 2293 os << "that is annotated as CF_RETURNS_NOT_RETAINED"; 2294 else if (D->getAttr<NSReturnsNotRetainedAttr>()) 2295 os << "that is annotated as NS_RETURNS_NOT_RETAINED"; 2296 else { 2297 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2298 os << "whose name ('" << MD->getSelector().getAsString() 2299 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2300 " This violates the naming convention rules" 2301 " given in the Memory Management Guide for Cocoa"; 2302 } 2303 else { 2304 const FunctionDecl *FD = cast<FunctionDecl>(D); 2305 os << "whose name ('" << *FD 2306 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2307 " convention rules given in the Memory Management Guide for Core" 2308 " Foundation"; 2309 } 2310 } 2311 } 2312 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2313 const ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2314 os << " and returned from method '" << MD.getSelector().getAsString() 2315 << "' is potentially leaked when using garbage collection. Callers " 2316 "of this method do not expect a returned object with a +1 retain " 2317 "count since they expect the object to be managed by the garbage " 2318 "collector"; 2319 } 2320 else 2321 os << " is not referenced later in this execution path and has a retain " 2322 "count of +" << RV->getCount(); 2323 2324 return new PathDiagnosticEventPiece(L, os.str()); 2325 } 2326 2327 CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2328 bool GCEnabled, const SummaryLogTy &Log, 2329 ExplodedNode *n, SymbolRef sym, 2330 CheckerContext &Ctx, 2331 bool IncludeAllocationLine) 2332 : CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2333 2334 // Most bug reports are cached at the location where they occurred. 2335 // With leaks, we want to unique them by the location where they were 2336 // allocated, and only report a single path. To do this, we need to find 2337 // the allocation site of a piece of tracked memory, which we do via a 2338 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2339 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2340 // that all ancestor nodes that represent the allocation site have the 2341 // same SourceLocation. 2342 const ExplodedNode *AllocNode = 0; 2343 2344 const SourceManager& SMgr = Ctx.getSourceManager(); 2345 2346 AllocationInfo AllocI = 2347 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2348 2349 AllocNode = AllocI.N; 2350 AllocBinding = AllocI.R; 2351 markInteresting(AllocI.InterestingMethodContext); 2352 2353 // Get the SourceLocation for the allocation site. 2354 // FIXME: This will crash the analyzer if an allocation comes from an 2355 // implicit call. (Currently there are no such allocations in Cocoa, though.) 2356 const Stmt *AllocStmt; 2357 ProgramPoint P = AllocNode->getLocation(); 2358 if (Optional<CallExitEnd> Exit = P.getAs<CallExitEnd>()) 2359 AllocStmt = Exit->getCalleeContext()->getCallSite(); 2360 else 2361 AllocStmt = P.castAs<PostStmt>().getStmt(); 2362 assert(AllocStmt && "All allocations must come from explicit calls"); 2363 2364 PathDiagnosticLocation AllocLocation = 2365 PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2366 AllocNode->getLocationContext()); 2367 Location = AllocLocation; 2368 2369 // Set uniqieing info, which will be used for unique the bug reports. The 2370 // leaks should be uniqued on the allocation site. 2371 UniqueingLocation = AllocLocation; 2372 UniqueingDecl = AllocNode->getLocationContext()->getDecl(); 2373 2374 // Fill in the description of the bug. 2375 Description.clear(); 2376 llvm::raw_string_ostream os(Description); 2377 os << "Potential leak "; 2378 if (GCEnabled) 2379 os << "(when using garbage collection) "; 2380 os << "of an object"; 2381 2382 if (AllocBinding) { 2383 os << " stored into '" << AllocBinding->getString() << '\''; 2384 if (IncludeAllocationLine) { 2385 FullSourceLoc SL(AllocStmt->getLocStart(), Ctx.getSourceManager()); 2386 os << " (allocated on line " << SL.getSpellingLineNumber() << ")"; 2387 } 2388 } 2389 2390 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2391 } 2392 2393 //===----------------------------------------------------------------------===// 2394 // Main checker logic. 2395 //===----------------------------------------------------------------------===// 2396 2397 namespace { 2398 class RetainCountChecker 2399 : public Checker< check::Bind, 2400 check::DeadSymbols, 2401 check::EndAnalysis, 2402 check::EndFunction, 2403 check::PostStmt<BlockExpr>, 2404 check::PostStmt<CastExpr>, 2405 check::PostStmt<ObjCArrayLiteral>, 2406 check::PostStmt<ObjCDictionaryLiteral>, 2407 check::PostStmt<ObjCBoxedExpr>, 2408 check::PostCall, 2409 check::PreStmt<ReturnStmt>, 2410 check::RegionChanges, 2411 eval::Assume, 2412 eval::Call > { 2413 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2414 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2415 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2416 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2417 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2418 2419 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2420 2421 // This map is only used to ensure proper deletion of any allocated tags. 2422 mutable SymbolTagMap DeadSymbolTags; 2423 2424 mutable OwningPtr<RetainSummaryManager> Summaries; 2425 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2426 mutable SummaryLogTy SummaryLog; 2427 mutable bool ShouldResetSummaryLog; 2428 2429 /// Optional setting to indicate if leak reports should include 2430 /// the allocation line. 2431 mutable bool IncludeAllocationLine; 2432 2433 public: 2434 RetainCountChecker(AnalyzerOptions &AO) 2435 : ShouldResetSummaryLog(false), 2436 IncludeAllocationLine(shouldIncludeAllocationSiteInLeakDiagnostics(AO)) {} 2437 2438 virtual ~RetainCountChecker() { 2439 DeleteContainerSeconds(DeadSymbolTags); 2440 } 2441 2442 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2443 ExprEngine &Eng) const { 2444 // FIXME: This is a hack to make sure the summary log gets cleared between 2445 // analyses of different code bodies. 2446 // 2447 // Why is this necessary? Because a checker's lifetime is tied to a 2448 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2449 // Once in a blue moon, a new ExplodedNode will have the same address as an 2450 // old one with an associated summary, and the bug report visitor gets very 2451 // confused. (To make things worse, the summary lifetime is currently also 2452 // tied to a code body, so we get a crash instead of incorrect results.) 2453 // 2454 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2455 // changes, things will start going wrong again. Really the lifetime of this 2456 // log needs to be tied to either the specific nodes in it or the entire 2457 // ExplodedGraph, not to a specific part of the code being analyzed. 2458 // 2459 // (Also, having stateful local data means that the same checker can't be 2460 // used from multiple threads, but a lot of checkers have incorrect 2461 // assumptions about that anyway. So that wasn't a priority at the time of 2462 // this fix.) 2463 // 2464 // This happens at the end of analysis, but bug reports are emitted /after/ 2465 // this point. So we can't just clear the summary log now. Instead, we mark 2466 // that the next time we access the summary log, it should be cleared. 2467 2468 // If we never reset the summary log during /this/ code body analysis, 2469 // there were no new summaries. There might still have been summaries from 2470 // the /last/ analysis, so clear them out to make sure the bug report 2471 // visitors don't get confused. 2472 if (ShouldResetSummaryLog) 2473 SummaryLog.clear(); 2474 2475 ShouldResetSummaryLog = !SummaryLog.empty(); 2476 } 2477 2478 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2479 bool GCEnabled) const { 2480 if (GCEnabled) { 2481 if (!leakWithinFunctionGC) 2482 leakWithinFunctionGC.reset(new Leak("Leak of object when using " 2483 "garbage collection")); 2484 return leakWithinFunctionGC.get(); 2485 } else { 2486 if (!leakWithinFunction) { 2487 if (LOpts.getGC() == LangOptions::HybridGC) { 2488 leakWithinFunction.reset(new Leak("Leak of object when not using " 2489 "garbage collection (GC) in " 2490 "dual GC/non-GC code")); 2491 } else { 2492 leakWithinFunction.reset(new Leak("Leak")); 2493 } 2494 } 2495 return leakWithinFunction.get(); 2496 } 2497 } 2498 2499 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2500 if (GCEnabled) { 2501 if (!leakAtReturnGC) 2502 leakAtReturnGC.reset(new Leak("Leak of returned object when using " 2503 "garbage collection")); 2504 return leakAtReturnGC.get(); 2505 } else { 2506 if (!leakAtReturn) { 2507 if (LOpts.getGC() == LangOptions::HybridGC) { 2508 leakAtReturn.reset(new Leak("Leak of returned object when not using " 2509 "garbage collection (GC) in dual " 2510 "GC/non-GC code")); 2511 } else { 2512 leakAtReturn.reset(new Leak("Leak of returned object")); 2513 } 2514 } 2515 return leakAtReturn.get(); 2516 } 2517 } 2518 2519 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2520 bool GCEnabled) const { 2521 // FIXME: We don't support ARC being turned on and off during one analysis. 2522 // (nor, for that matter, do we support changing ASTContexts) 2523 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2524 if (GCEnabled) { 2525 if (!SummariesGC) 2526 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2527 else 2528 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2529 return *SummariesGC; 2530 } else { 2531 if (!Summaries) 2532 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2533 else 2534 assert(Summaries->isARCEnabled() == ARCEnabled); 2535 return *Summaries; 2536 } 2537 } 2538 2539 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2540 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2541 } 2542 2543 void printState(raw_ostream &Out, ProgramStateRef State, 2544 const char *NL, const char *Sep) const; 2545 2546 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2547 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2548 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2549 2550 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2551 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2552 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2553 2554 void checkPostCall(const CallEvent &Call, CheckerContext &C) const; 2555 2556 void checkSummary(const RetainSummary &Summ, const CallEvent &Call, 2557 CheckerContext &C) const; 2558 2559 void processSummaryOfInlined(const RetainSummary &Summ, 2560 const CallEvent &Call, 2561 CheckerContext &C) const; 2562 2563 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2564 2565 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2566 bool Assumption) const; 2567 2568 ProgramStateRef 2569 checkRegionChanges(ProgramStateRef state, 2570 const InvalidatedSymbols *invalidated, 2571 ArrayRef<const MemRegion *> ExplicitRegions, 2572 ArrayRef<const MemRegion *> Regions, 2573 const CallEvent *Call) const; 2574 2575 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2576 return true; 2577 } 2578 2579 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2580 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2581 ExplodedNode *Pred, RetEffect RE, RefVal X, 2582 SymbolRef Sym, ProgramStateRef state) const; 2583 2584 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2585 void checkEndFunction(CheckerContext &C) const; 2586 2587 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2588 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2589 CheckerContext &C) const; 2590 2591 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2592 RefVal::Kind ErrorKind, SymbolRef Sym, 2593 CheckerContext &C) const; 2594 2595 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2596 2597 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2598 2599 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2600 SymbolRef sid, RefVal V, 2601 SmallVectorImpl<SymbolRef> &Leaked) const; 2602 2603 ProgramStateRef 2604 handleAutoreleaseCounts(ProgramStateRef state, ExplodedNode *Pred, 2605 const ProgramPointTag *Tag, CheckerContext &Ctx, 2606 SymbolRef Sym, RefVal V) const; 2607 2608 ExplodedNode *processLeaks(ProgramStateRef state, 2609 SmallVectorImpl<SymbolRef> &Leaked, 2610 CheckerContext &Ctx, 2611 ExplodedNode *Pred = 0) const; 2612 }; 2613 } // end anonymous namespace 2614 2615 namespace { 2616 class StopTrackingCallback : public SymbolVisitor { 2617 ProgramStateRef state; 2618 public: 2619 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2620 ProgramStateRef getState() const { return state; } 2621 2622 bool VisitSymbol(SymbolRef sym) { 2623 state = state->remove<RefBindings>(sym); 2624 return true; 2625 } 2626 }; 2627 } // end anonymous namespace 2628 2629 //===----------------------------------------------------------------------===// 2630 // Handle statements that may have an effect on refcounts. 2631 //===----------------------------------------------------------------------===// 2632 2633 void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2634 CheckerContext &C) const { 2635 2636 // Scan the BlockDecRefExprs for any object the retain count checker 2637 // may be tracking. 2638 if (!BE->getBlockDecl()->hasCaptures()) 2639 return; 2640 2641 ProgramStateRef state = C.getState(); 2642 const BlockDataRegion *R = 2643 cast<BlockDataRegion>(state->getSVal(BE, 2644 C.getLocationContext()).getAsRegion()); 2645 2646 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2647 E = R->referenced_vars_end(); 2648 2649 if (I == E) 2650 return; 2651 2652 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2653 // via captured variables, even though captured variables result in a copy 2654 // and in implicit increment/decrement of a retain count. 2655 SmallVector<const MemRegion*, 10> Regions; 2656 const LocationContext *LC = C.getLocationContext(); 2657 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2658 2659 for ( ; I != E; ++I) { 2660 const VarRegion *VR = I.getCapturedRegion(); 2661 if (VR->getSuperRegion() == R) { 2662 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2663 } 2664 Regions.push_back(VR); 2665 } 2666 2667 state = 2668 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2669 Regions.data() + Regions.size()).getState(); 2670 C.addTransition(state); 2671 } 2672 2673 void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2674 CheckerContext &C) const { 2675 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2676 if (!BE) 2677 return; 2678 2679 ArgEffect AE = IncRef; 2680 2681 switch (BE->getBridgeKind()) { 2682 case clang::OBC_Bridge: 2683 // Do nothing. 2684 return; 2685 case clang::OBC_BridgeRetained: 2686 AE = IncRef; 2687 break; 2688 case clang::OBC_BridgeTransfer: 2689 AE = DecRefBridgedTransfered; 2690 break; 2691 } 2692 2693 ProgramStateRef state = C.getState(); 2694 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2695 if (!Sym) 2696 return; 2697 const RefVal* T = getRefBinding(state, Sym); 2698 if (!T) 2699 return; 2700 2701 RefVal::Kind hasErr = (RefVal::Kind) 0; 2702 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2703 2704 if (hasErr) { 2705 // FIXME: If we get an error during a bridge cast, should we report it? 2706 // Should we assert that there is no error? 2707 return; 2708 } 2709 2710 C.addTransition(state); 2711 } 2712 2713 void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2714 const Expr *Ex) const { 2715 ProgramStateRef state = C.getState(); 2716 const ExplodedNode *pred = C.getPredecessor(); 2717 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2718 it != et ; ++it) { 2719 const Stmt *child = *it; 2720 SVal V = state->getSVal(child, pred->getLocationContext()); 2721 if (SymbolRef sym = V.getAsSymbol()) 2722 if (const RefVal* T = getRefBinding(state, sym)) { 2723 RefVal::Kind hasErr = (RefVal::Kind) 0; 2724 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2725 if (hasErr) { 2726 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2727 return; 2728 } 2729 } 2730 } 2731 2732 // Return the object as autoreleased. 2733 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2734 if (SymbolRef sym = 2735 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2736 QualType ResultTy = Ex->getType(); 2737 state = setRefBinding(state, sym, 2738 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2739 } 2740 2741 C.addTransition(state); 2742 } 2743 2744 void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2745 CheckerContext &C) const { 2746 // Apply the 'MayEscape' to all values. 2747 processObjCLiterals(C, AL); 2748 } 2749 2750 void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2751 CheckerContext &C) const { 2752 // Apply the 'MayEscape' to all keys and values. 2753 processObjCLiterals(C, DL); 2754 } 2755 2756 void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2757 CheckerContext &C) const { 2758 const ExplodedNode *Pred = C.getPredecessor(); 2759 const LocationContext *LCtx = Pred->getLocationContext(); 2760 ProgramStateRef State = Pred->getState(); 2761 2762 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2763 QualType ResultTy = Ex->getType(); 2764 State = setRefBinding(State, Sym, 2765 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2766 } 2767 2768 C.addTransition(State); 2769 } 2770 2771 void RetainCountChecker::checkPostCall(const CallEvent &Call, 2772 CheckerContext &C) const { 2773 RetainSummaryManager &Summaries = getSummaryManager(C); 2774 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState()); 2775 2776 if (C.wasInlined) { 2777 processSummaryOfInlined(*Summ, Call, C); 2778 return; 2779 } 2780 checkSummary(*Summ, Call, C); 2781 } 2782 2783 /// GetReturnType - Used to get the return type of a message expression or 2784 /// function call with the intention of affixing that type to a tracked symbol. 2785 /// While the return type can be queried directly from RetEx, when 2786 /// invoking class methods we augment to the return type to be that of 2787 /// a pointer to the class (as opposed it just being id). 2788 // FIXME: We may be able to do this with related result types instead. 2789 // This function is probably overestimating. 2790 static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2791 QualType RetTy = RetE->getType(); 2792 // If RetE is not a message expression just return its type. 2793 // If RetE is a message expression, return its types if it is something 2794 /// more specific than id. 2795 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2796 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2797 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2798 PT->isObjCClassType()) { 2799 // At this point we know the return type of the message expression is 2800 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2801 // is a call to a class method whose type we can resolve. In such 2802 // cases, promote the return type to XXX* (where XXX is the class). 2803 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2804 return !D ? RetTy : 2805 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2806 } 2807 2808 return RetTy; 2809 } 2810 2811 // We don't always get the exact modeling of the function with regards to the 2812 // retain count checker even when the function is inlined. For example, we need 2813 // to stop tracking the symbols which were marked with StopTrackingHard. 2814 void RetainCountChecker::processSummaryOfInlined(const RetainSummary &Summ, 2815 const CallEvent &CallOrMsg, 2816 CheckerContext &C) const { 2817 ProgramStateRef state = C.getState(); 2818 2819 // Evaluate the effect of the arguments. 2820 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2821 if (Summ.getArg(idx) == StopTrackingHard) { 2822 SVal V = CallOrMsg.getArgSVal(idx); 2823 if (SymbolRef Sym = V.getAsLocSymbol()) { 2824 state = removeRefBinding(state, Sym); 2825 } 2826 } 2827 } 2828 2829 // Evaluate the effect on the message receiver. 2830 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2831 if (MsgInvocation) { 2832 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2833 if (Summ.getReceiverEffect() == StopTrackingHard) { 2834 state = removeRefBinding(state, Sym); 2835 } 2836 } 2837 } 2838 2839 // Consult the summary for the return value. 2840 RetEffect RE = Summ.getRetEffect(); 2841 if (RE.getKind() == RetEffect::NoRetHard) { 2842 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2843 if (Sym) 2844 state = removeRefBinding(state, Sym); 2845 } 2846 2847 C.addTransition(state); 2848 } 2849 2850 void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2851 const CallEvent &CallOrMsg, 2852 CheckerContext &C) const { 2853 ProgramStateRef state = C.getState(); 2854 2855 // Evaluate the effect of the arguments. 2856 RefVal::Kind hasErr = (RefVal::Kind) 0; 2857 SourceRange ErrorRange; 2858 SymbolRef ErrorSym = 0; 2859 2860 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2861 SVal V = CallOrMsg.getArgSVal(idx); 2862 2863 if (SymbolRef Sym = V.getAsLocSymbol()) { 2864 if (const RefVal *T = getRefBinding(state, Sym)) { 2865 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2866 if (hasErr) { 2867 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2868 ErrorSym = Sym; 2869 break; 2870 } 2871 } 2872 } 2873 } 2874 2875 // Evaluate the effect on the message receiver. 2876 bool ReceiverIsTracked = false; 2877 if (!hasErr) { 2878 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2879 if (MsgInvocation) { 2880 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2881 if (const RefVal *T = getRefBinding(state, Sym)) { 2882 ReceiverIsTracked = true; 2883 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2884 hasErr, C); 2885 if (hasErr) { 2886 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange(); 2887 ErrorSym = Sym; 2888 } 2889 } 2890 } 2891 } 2892 } 2893 2894 // Process any errors. 2895 if (hasErr) { 2896 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2897 return; 2898 } 2899 2900 // Consult the summary for the return value. 2901 RetEffect RE = Summ.getRetEffect(); 2902 2903 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2904 if (ReceiverIsTracked) 2905 RE = getSummaryManager(C).getObjAllocRetEffect(); 2906 else 2907 RE = RetEffect::MakeNoRet(); 2908 } 2909 2910 switch (RE.getKind()) { 2911 default: 2912 llvm_unreachable("Unhandled RetEffect."); 2913 2914 case RetEffect::NoRet: 2915 case RetEffect::NoRetHard: 2916 // No work necessary. 2917 break; 2918 2919 case RetEffect::OwnedAllocatedSymbol: 2920 case RetEffect::OwnedSymbol: { 2921 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2922 if (!Sym) 2923 break; 2924 2925 // Use the result type from the CallEvent as it automatically adjusts 2926 // for methods/functions that return references. 2927 QualType ResultTy = CallOrMsg.getResultType(); 2928 state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(), 2929 ResultTy)); 2930 2931 // FIXME: Add a flag to the checker where allocations are assumed to 2932 // *not* fail. 2933 break; 2934 } 2935 2936 case RetEffect::GCNotOwnedSymbol: 2937 case RetEffect::ARCNotOwnedSymbol: 2938 case RetEffect::NotOwnedSymbol: { 2939 const Expr *Ex = CallOrMsg.getOriginExpr(); 2940 SymbolRef Sym = CallOrMsg.getReturnValue().getAsSymbol(); 2941 if (!Sym) 2942 break; 2943 assert(Ex); 2944 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2945 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2946 state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(), 2947 ResultTy)); 2948 break; 2949 } 2950 } 2951 2952 // This check is actually necessary; otherwise the statement builder thinks 2953 // we've hit a previously-found path. 2954 // Normally addTransition takes care of this, but we want the node pointer. 2955 ExplodedNode *NewNode; 2956 if (state == C.getState()) { 2957 NewNode = C.getPredecessor(); 2958 } else { 2959 NewNode = C.addTransition(state); 2960 } 2961 2962 // Annotate the node with summary we used. 2963 if (NewNode) { 2964 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2965 if (ShouldResetSummaryLog) { 2966 SummaryLog.clear(); 2967 ShouldResetSummaryLog = false; 2968 } 2969 SummaryLog[NewNode] = &Summ; 2970 } 2971 } 2972 2973 2974 ProgramStateRef 2975 RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2976 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2977 CheckerContext &C) const { 2978 // In GC mode [... release] and [... retain] do nothing. 2979 // In ARC mode they shouldn't exist at all, but we just ignore them. 2980 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2981 if (!IgnoreRetainMsg) 2982 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 2983 2984 switch (E) { 2985 default: 2986 break; 2987 case IncRefMsg: 2988 E = IgnoreRetainMsg ? DoNothing : IncRef; 2989 break; 2990 case DecRefMsg: 2991 E = IgnoreRetainMsg ? DoNothing : DecRef; 2992 break; 2993 case DecRefMsgAndStopTrackingHard: 2994 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTrackingHard; 2995 break; 2996 case MakeCollectable: 2997 E = C.isObjCGCEnabled() ? DecRef : DoNothing; 2998 break; 2999 } 3000 3001 // Handle all use-after-releases. 3002 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 3003 V = V ^ RefVal::ErrorUseAfterRelease; 3004 hasErr = V.getKind(); 3005 return setRefBinding(state, sym, V); 3006 } 3007 3008 switch (E) { 3009 case DecRefMsg: 3010 case IncRefMsg: 3011 case MakeCollectable: 3012 case DecRefMsgAndStopTrackingHard: 3013 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 3014 3015 case Dealloc: 3016 // Any use of -dealloc in GC is *bad*. 3017 if (C.isObjCGCEnabled()) { 3018 V = V ^ RefVal::ErrorDeallocGC; 3019 hasErr = V.getKind(); 3020 break; 3021 } 3022 3023 switch (V.getKind()) { 3024 default: 3025 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 3026 case RefVal::Owned: 3027 // The object immediately transitions to the released state. 3028 V = V ^ RefVal::Released; 3029 V.clearCounts(); 3030 return setRefBinding(state, sym, V); 3031 case RefVal::NotOwned: 3032 V = V ^ RefVal::ErrorDeallocNotOwned; 3033 hasErr = V.getKind(); 3034 break; 3035 } 3036 break; 3037 3038 case MayEscape: 3039 if (V.getKind() == RefVal::Owned) { 3040 V = V ^ RefVal::NotOwned; 3041 break; 3042 } 3043 3044 // Fall-through. 3045 3046 case DoNothing: 3047 return state; 3048 3049 case Autorelease: 3050 if (C.isObjCGCEnabled()) 3051 return state; 3052 // Update the autorelease counts. 3053 V = V.autorelease(); 3054 break; 3055 3056 case StopTracking: 3057 case StopTrackingHard: 3058 return removeRefBinding(state, sym); 3059 3060 case IncRef: 3061 switch (V.getKind()) { 3062 default: 3063 llvm_unreachable("Invalid RefVal state for a retain."); 3064 case RefVal::Owned: 3065 case RefVal::NotOwned: 3066 V = V + 1; 3067 break; 3068 case RefVal::Released: 3069 // Non-GC cases are handled above. 3070 assert(C.isObjCGCEnabled()); 3071 V = (V ^ RefVal::Owned) + 1; 3072 break; 3073 } 3074 break; 3075 3076 case DecRef: 3077 case DecRefBridgedTransfered: 3078 case DecRefAndStopTrackingHard: 3079 switch (V.getKind()) { 3080 default: 3081 // case 'RefVal::Released' handled above. 3082 llvm_unreachable("Invalid RefVal state for a release."); 3083 3084 case RefVal::Owned: 3085 assert(V.getCount() > 0); 3086 if (V.getCount() == 1) 3087 V = V ^ (E == DecRefBridgedTransfered ? 3088 RefVal::NotOwned : RefVal::Released); 3089 else if (E == DecRefAndStopTrackingHard) 3090 return removeRefBinding(state, sym); 3091 3092 V = V - 1; 3093 break; 3094 3095 case RefVal::NotOwned: 3096 if (V.getCount() > 0) { 3097 if (E == DecRefAndStopTrackingHard) 3098 return removeRefBinding(state, sym); 3099 V = V - 1; 3100 } else { 3101 V = V ^ RefVal::ErrorReleaseNotOwned; 3102 hasErr = V.getKind(); 3103 } 3104 break; 3105 3106 case RefVal::Released: 3107 // Non-GC cases are handled above. 3108 assert(C.isObjCGCEnabled()); 3109 V = V ^ RefVal::ErrorUseAfterRelease; 3110 hasErr = V.getKind(); 3111 break; 3112 } 3113 break; 3114 } 3115 return setRefBinding(state, sym, V); 3116 } 3117 3118 void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3119 SourceRange ErrorRange, 3120 RefVal::Kind ErrorKind, 3121 SymbolRef Sym, 3122 CheckerContext &C) const { 3123 ExplodedNode *N = C.generateSink(St); 3124 if (!N) 3125 return; 3126 3127 CFRefBug *BT; 3128 switch (ErrorKind) { 3129 default: 3130 llvm_unreachable("Unhandled error."); 3131 case RefVal::ErrorUseAfterRelease: 3132 if (!useAfterRelease) 3133 useAfterRelease.reset(new UseAfterRelease()); 3134 BT = &*useAfterRelease; 3135 break; 3136 case RefVal::ErrorReleaseNotOwned: 3137 if (!releaseNotOwned) 3138 releaseNotOwned.reset(new BadRelease()); 3139 BT = &*releaseNotOwned; 3140 break; 3141 case RefVal::ErrorDeallocGC: 3142 if (!deallocGC) 3143 deallocGC.reset(new DeallocGC()); 3144 BT = &*deallocGC; 3145 break; 3146 case RefVal::ErrorDeallocNotOwned: 3147 if (!deallocNotOwned) 3148 deallocNotOwned.reset(new DeallocNotOwned()); 3149 BT = &*deallocNotOwned; 3150 break; 3151 } 3152 3153 assert(BT); 3154 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3155 C.isObjCGCEnabled(), SummaryLog, 3156 N, Sym); 3157 report->addRange(ErrorRange); 3158 C.emitReport(report); 3159 } 3160 3161 //===----------------------------------------------------------------------===// 3162 // Handle the return values of retain-count-related functions. 3163 //===----------------------------------------------------------------------===// 3164 3165 bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3166 // Get the callee. We're only interested in simple C functions. 3167 ProgramStateRef state = C.getState(); 3168 const FunctionDecl *FD = C.getCalleeDecl(CE); 3169 if (!FD) 3170 return false; 3171 3172 IdentifierInfo *II = FD->getIdentifier(); 3173 if (!II) 3174 return false; 3175 3176 // For now, we're only handling the functions that return aliases of their 3177 // arguments: CFRetain and CFMakeCollectable (and their families). 3178 // Eventually we should add other functions we can model entirely, 3179 // such as CFRelease, which don't invalidate their arguments or globals. 3180 if (CE->getNumArgs() != 1) 3181 return false; 3182 3183 // Get the name of the function. 3184 StringRef FName = II->getName(); 3185 FName = FName.substr(FName.find_first_not_of('_')); 3186 3187 // See if it's one of the specific functions we know how to eval. 3188 bool canEval = false; 3189 3190 QualType ResultTy = CE->getCallReturnType(); 3191 if (ResultTy->isObjCIdType()) { 3192 // Handle: id NSMakeCollectable(CFTypeRef) 3193 canEval = II->isStr("NSMakeCollectable"); 3194 } else if (ResultTy->isPointerType()) { 3195 // Handle: (CF|CG)Retain 3196 // CFMakeCollectable 3197 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3198 if (cocoa::isRefType(ResultTy, "CF", FName) || 3199 cocoa::isRefType(ResultTy, "CG", FName)) { 3200 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3201 } 3202 } 3203 3204 if (!canEval) 3205 return false; 3206 3207 // Bind the return value. 3208 const LocationContext *LCtx = C.getLocationContext(); 3209 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3210 if (RetVal.isUnknown()) { 3211 // If the receiver is unknown, conjure a return value. 3212 SValBuilder &SVB = C.getSValBuilder(); 3213 RetVal = SVB.conjureSymbolVal(0, CE, LCtx, ResultTy, C.blockCount()); 3214 } 3215 state = state->BindExpr(CE, LCtx, RetVal, false); 3216 3217 // FIXME: This should not be necessary, but otherwise the argument seems to be 3218 // considered alive during the next statement. 3219 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3220 // Save the refcount status of the argument. 3221 SymbolRef Sym = RetVal.getAsLocSymbol(); 3222 const RefVal *Binding = 0; 3223 if (Sym) 3224 Binding = getRefBinding(state, Sym); 3225 3226 // Invalidate the argument region. 3227 state = state->invalidateRegions(ArgRegion, CE, C.blockCount(), LCtx, 3228 /*CausesPointerEscape*/ false); 3229 3230 // Restore the refcount status of the argument. 3231 if (Binding) 3232 state = setRefBinding(state, Sym, *Binding); 3233 } 3234 3235 C.addTransition(state); 3236 return true; 3237 } 3238 3239 //===----------------------------------------------------------------------===// 3240 // Handle return statements. 3241 //===----------------------------------------------------------------------===// 3242 3243 void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3244 CheckerContext &C) const { 3245 3246 // Only adjust the reference count if this is the top-level call frame, 3247 // and not the result of inlining. In the future, we should do 3248 // better checking even for inlined calls, and see if they match 3249 // with their expected semantics (e.g., the method should return a retained 3250 // object, etc.). 3251 if (!C.inTopFrame()) 3252 return; 3253 3254 const Expr *RetE = S->getRetValue(); 3255 if (!RetE) 3256 return; 3257 3258 ProgramStateRef state = C.getState(); 3259 SymbolRef Sym = 3260 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3261 if (!Sym) 3262 return; 3263 3264 // Get the reference count binding (if any). 3265 const RefVal *T = getRefBinding(state, Sym); 3266 if (!T) 3267 return; 3268 3269 // Change the reference count. 3270 RefVal X = *T; 3271 3272 switch (X.getKind()) { 3273 case RefVal::Owned: { 3274 unsigned cnt = X.getCount(); 3275 assert(cnt > 0); 3276 X.setCount(cnt - 1); 3277 X = X ^ RefVal::ReturnedOwned; 3278 break; 3279 } 3280 3281 case RefVal::NotOwned: { 3282 unsigned cnt = X.getCount(); 3283 if (cnt) { 3284 X.setCount(cnt - 1); 3285 X = X ^ RefVal::ReturnedOwned; 3286 } 3287 else { 3288 X = X ^ RefVal::ReturnedNotOwned; 3289 } 3290 break; 3291 } 3292 3293 default: 3294 return; 3295 } 3296 3297 // Update the binding. 3298 state = setRefBinding(state, Sym, X); 3299 ExplodedNode *Pred = C.addTransition(state); 3300 3301 // At this point we have updated the state properly. 3302 // Everything after this is merely checking to see if the return value has 3303 // been over- or under-retained. 3304 3305 // Did we cache out? 3306 if (!Pred) 3307 return; 3308 3309 // Update the autorelease counts. 3310 static SimpleProgramPointTag 3311 AutoreleaseTag("RetainCountChecker : Autorelease"); 3312 state = handleAutoreleaseCounts(state, Pred, &AutoreleaseTag, C, Sym, X); 3313 3314 // Did we cache out? 3315 if (!state) 3316 return; 3317 3318 // Get the updated binding. 3319 T = getRefBinding(state, Sym); 3320 assert(T); 3321 X = *T; 3322 3323 // Consult the summary of the enclosing method. 3324 RetainSummaryManager &Summaries = getSummaryManager(C); 3325 const Decl *CD = &Pred->getCodeDecl(); 3326 RetEffect RE = RetEffect::MakeNoRet(); 3327 3328 // FIXME: What is the convention for blocks? Is there one? 3329 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3330 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3331 RE = Summ->getRetEffect(); 3332 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3333 if (!isa<CXXMethodDecl>(FD)) { 3334 const RetainSummary *Summ = Summaries.getFunctionSummary(FD); 3335 RE = Summ->getRetEffect(); 3336 } 3337 } 3338 3339 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3340 } 3341 3342 void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3343 CheckerContext &C, 3344 ExplodedNode *Pred, 3345 RetEffect RE, RefVal X, 3346 SymbolRef Sym, 3347 ProgramStateRef state) const { 3348 // Any leaks or other errors? 3349 if (X.isReturnedOwned() && X.getCount() == 0) { 3350 if (RE.getKind() != RetEffect::NoRet) { 3351 bool hasError = false; 3352 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3353 // Things are more complicated with garbage collection. If the 3354 // returned object is suppose to be an Objective-C object, we have 3355 // a leak (as the caller expects a GC'ed object) because no 3356 // method should return ownership unless it returns a CF object. 3357 hasError = true; 3358 X = X ^ RefVal::ErrorGCLeakReturned; 3359 } 3360 else if (!RE.isOwned()) { 3361 // Either we are using GC and the returned object is a CF type 3362 // or we aren't using GC. In either case, we expect that the 3363 // enclosing method is expected to return ownership. 3364 hasError = true; 3365 X = X ^ RefVal::ErrorLeakReturned; 3366 } 3367 3368 if (hasError) { 3369 // Generate an error node. 3370 state = setRefBinding(state, Sym, X); 3371 3372 static SimpleProgramPointTag 3373 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3374 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3375 if (N) { 3376 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3377 bool GCEnabled = C.isObjCGCEnabled(); 3378 CFRefReport *report = 3379 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3380 LOpts, GCEnabled, SummaryLog, 3381 N, Sym, C, IncludeAllocationLine); 3382 3383 C.emitReport(report); 3384 } 3385 } 3386 } 3387 } else if (X.isReturnedNotOwned()) { 3388 if (RE.isOwned()) { 3389 // Trying to return a not owned object to a caller expecting an 3390 // owned object. 3391 state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned); 3392 3393 static SimpleProgramPointTag 3394 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3395 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3396 if (N) { 3397 if (!returnNotOwnedForOwned) 3398 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3399 3400 CFRefReport *report = 3401 new CFRefReport(*returnNotOwnedForOwned, 3402 C.getASTContext().getLangOpts(), 3403 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3404 C.emitReport(report); 3405 } 3406 } 3407 } 3408 } 3409 3410 //===----------------------------------------------------------------------===// 3411 // Check various ways a symbol can be invalidated. 3412 //===----------------------------------------------------------------------===// 3413 3414 void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3415 CheckerContext &C) const { 3416 // Are we storing to something that causes the value to "escape"? 3417 bool escapes = true; 3418 3419 // A value escapes in three possible cases (this may change): 3420 // 3421 // (1) we are binding to something that is not a memory region. 3422 // (2) we are binding to a memregion that does not have stack storage 3423 // (3) we are binding to a memregion with stack storage that the store 3424 // does not understand. 3425 ProgramStateRef state = C.getState(); 3426 3427 if (Optional<loc::MemRegionVal> regionLoc = loc.getAs<loc::MemRegionVal>()) { 3428 escapes = !regionLoc->getRegion()->hasStackStorage(); 3429 3430 if (!escapes) { 3431 // To test (3), generate a new state with the binding added. If it is 3432 // the same state, then it escapes (since the store cannot represent 3433 // the binding). 3434 // Do this only if we know that the store is not supposed to generate the 3435 // same state. 3436 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3437 if (StoredVal != val) 3438 escapes = (state == (state->bindLoc(*regionLoc, val))); 3439 } 3440 if (!escapes) { 3441 // Case 4: We do not currently model what happens when a symbol is 3442 // assigned to a struct field, so be conservative here and let the symbol 3443 // go. TODO: This could definitely be improved upon. 3444 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3445 } 3446 } 3447 3448 // If our store can represent the binding and we aren't storing to something 3449 // that doesn't have local storage then just return and have the simulation 3450 // state continue as is. 3451 if (!escapes) 3452 return; 3453 3454 // Otherwise, find all symbols referenced by 'val' that we are tracking 3455 // and stop tracking them. 3456 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3457 C.addTransition(state); 3458 } 3459 3460 ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3461 SVal Cond, 3462 bool Assumption) const { 3463 3464 // FIXME: We may add to the interface of evalAssume the list of symbols 3465 // whose assumptions have changed. For now we just iterate through the 3466 // bindings and check if any of the tracked symbols are NULL. This isn't 3467 // too bad since the number of symbols we will track in practice are 3468 // probably small and evalAssume is only called at branches and a few 3469 // other places. 3470 RefBindingsTy B = state->get<RefBindings>(); 3471 3472 if (B.isEmpty()) 3473 return state; 3474 3475 bool changed = false; 3476 RefBindingsTy::Factory &RefBFactory = state->get_context<RefBindings>(); 3477 3478 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3479 // Check if the symbol is null stop tracking the symbol. 3480 ConstraintManager &CMgr = state->getConstraintManager(); 3481 ConditionTruthVal AllocFailed = CMgr.isNull(state, I.getKey()); 3482 if (AllocFailed.isConstrainedTrue()) { 3483 changed = true; 3484 B = RefBFactory.remove(B, I.getKey()); 3485 } 3486 } 3487 3488 if (changed) 3489 state = state->set<RefBindings>(B); 3490 3491 return state; 3492 } 3493 3494 ProgramStateRef 3495 RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3496 const InvalidatedSymbols *invalidated, 3497 ArrayRef<const MemRegion *> ExplicitRegions, 3498 ArrayRef<const MemRegion *> Regions, 3499 const CallEvent *Call) const { 3500 if (!invalidated) 3501 return state; 3502 3503 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3504 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3505 E = ExplicitRegions.end(); I != E; ++I) { 3506 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3507 WhitelistedSymbols.insert(SR->getSymbol()); 3508 } 3509 3510 for (InvalidatedSymbols::const_iterator I=invalidated->begin(), 3511 E = invalidated->end(); I!=E; ++I) { 3512 SymbolRef sym = *I; 3513 if (WhitelistedSymbols.count(sym)) 3514 continue; 3515 // Remove any existing reference-count binding. 3516 state = removeRefBinding(state, sym); 3517 } 3518 return state; 3519 } 3520 3521 //===----------------------------------------------------------------------===// 3522 // Handle dead symbols and end-of-path. 3523 //===----------------------------------------------------------------------===// 3524 3525 ProgramStateRef 3526 RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3527 ExplodedNode *Pred, 3528 const ProgramPointTag *Tag, 3529 CheckerContext &Ctx, 3530 SymbolRef Sym, RefVal V) const { 3531 unsigned ACnt = V.getAutoreleaseCount(); 3532 3533 // No autorelease counts? Nothing to be done. 3534 if (!ACnt) 3535 return state; 3536 3537 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3538 unsigned Cnt = V.getCount(); 3539 3540 // FIXME: Handle sending 'autorelease' to already released object. 3541 3542 if (V.getKind() == RefVal::ReturnedOwned) 3543 ++Cnt; 3544 3545 if (ACnt <= Cnt) { 3546 if (ACnt == Cnt) { 3547 V.clearCounts(); 3548 if (V.getKind() == RefVal::ReturnedOwned) 3549 V = V ^ RefVal::ReturnedNotOwned; 3550 else 3551 V = V ^ RefVal::NotOwned; 3552 } else { 3553 V.setCount(V.getCount() - ACnt); 3554 V.setAutoreleaseCount(0); 3555 } 3556 return setRefBinding(state, Sym, V); 3557 } 3558 3559 // Woah! More autorelease counts then retain counts left. 3560 // Emit hard error. 3561 V = V ^ RefVal::ErrorOverAutorelease; 3562 state = setRefBinding(state, Sym, V); 3563 3564 ExplodedNode *N = Ctx.generateSink(state, Pred, Tag); 3565 if (N) { 3566 SmallString<128> sbuf; 3567 llvm::raw_svector_ostream os(sbuf); 3568 os << "Object was autoreleased "; 3569 if (V.getAutoreleaseCount() > 1) 3570 os << V.getAutoreleaseCount() << " times but the object "; 3571 else 3572 os << "but "; 3573 os << "has a +" << V.getCount() << " retain count"; 3574 3575 if (!overAutorelease) 3576 overAutorelease.reset(new OverAutorelease()); 3577 3578 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3579 CFRefReport *report = 3580 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3581 SummaryLog, N, Sym, os.str()); 3582 Ctx.emitReport(report); 3583 } 3584 3585 return 0; 3586 } 3587 3588 ProgramStateRef 3589 RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3590 SymbolRef sid, RefVal V, 3591 SmallVectorImpl<SymbolRef> &Leaked) const { 3592 bool hasLeak = false; 3593 if (V.isOwned()) 3594 hasLeak = true; 3595 else if (V.isNotOwned() || V.isReturnedOwned()) 3596 hasLeak = (V.getCount() > 0); 3597 3598 if (!hasLeak) 3599 return removeRefBinding(state, sid); 3600 3601 Leaked.push_back(sid); 3602 return setRefBinding(state, sid, V ^ RefVal::ErrorLeak); 3603 } 3604 3605 ExplodedNode * 3606 RetainCountChecker::processLeaks(ProgramStateRef state, 3607 SmallVectorImpl<SymbolRef> &Leaked, 3608 CheckerContext &Ctx, 3609 ExplodedNode *Pred) const { 3610 // Generate an intermediate node representing the leak point. 3611 ExplodedNode *N = Ctx.addTransition(state, Pred); 3612 3613 if (N) { 3614 for (SmallVectorImpl<SymbolRef>::iterator 3615 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3616 3617 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3618 bool GCEnabled = Ctx.isObjCGCEnabled(); 3619 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3620 : getLeakAtReturnBug(LOpts, GCEnabled); 3621 assert(BT && "BugType not initialized."); 3622 3623 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3624 SummaryLog, N, *I, Ctx, 3625 IncludeAllocationLine); 3626 Ctx.emitReport(report); 3627 } 3628 } 3629 3630 return N; 3631 } 3632 3633 void RetainCountChecker::checkEndFunction(CheckerContext &Ctx) const { 3634 ProgramStateRef state = Ctx.getState(); 3635 RefBindingsTy B = state->get<RefBindings>(); 3636 ExplodedNode *Pred = Ctx.getPredecessor(); 3637 3638 // Don't process anything within synthesized bodies. 3639 const LocationContext *LCtx = Pred->getLocationContext(); 3640 if (LCtx->getAnalysisDeclContext()->isBodyAutosynthesized()) { 3641 assert(LCtx->getParent()); 3642 return; 3643 } 3644 3645 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3646 state = handleAutoreleaseCounts(state, Pred, /*Tag=*/0, Ctx, 3647 I->first, I->second); 3648 if (!state) 3649 return; 3650 } 3651 3652 // If the current LocationContext has a parent, don't check for leaks. 3653 // We will do that later. 3654 // FIXME: we should instead check for imbalances of the retain/releases, 3655 // and suggest annotations. 3656 if (LCtx->getParent()) 3657 return; 3658 3659 B = state->get<RefBindings>(); 3660 SmallVector<SymbolRef, 10> Leaked; 3661 3662 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) 3663 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3664 3665 processLeaks(state, Leaked, Ctx, Pred); 3666 } 3667 3668 const ProgramPointTag * 3669 RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3670 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3671 if (!tag) { 3672 SmallString<64> buf; 3673 llvm::raw_svector_ostream out(buf); 3674 out << "RetainCountChecker : Dead Symbol : "; 3675 sym->dumpToStream(out); 3676 tag = new SimpleProgramPointTag(out.str()); 3677 } 3678 return tag; 3679 } 3680 3681 void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3682 CheckerContext &C) const { 3683 ExplodedNode *Pred = C.getPredecessor(); 3684 3685 ProgramStateRef state = C.getState(); 3686 RefBindingsTy B = state->get<RefBindings>(); 3687 SmallVector<SymbolRef, 10> Leaked; 3688 3689 // Update counts from autorelease pools 3690 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3691 E = SymReaper.dead_end(); I != E; ++I) { 3692 SymbolRef Sym = *I; 3693 if (const RefVal *T = B.lookup(Sym)){ 3694 // Use the symbol as the tag. 3695 // FIXME: This might not be as unique as we would like. 3696 const ProgramPointTag *Tag = getDeadSymbolTag(Sym); 3697 state = handleAutoreleaseCounts(state, Pred, Tag, C, Sym, *T); 3698 if (!state) 3699 return; 3700 3701 // Fetch the new reference count from the state, and use it to handle 3702 // this symbol. 3703 state = handleSymbolDeath(state, *I, *getRefBinding(state, Sym), Leaked); 3704 } 3705 } 3706 3707 if (Leaked.empty()) { 3708 C.addTransition(state); 3709 return; 3710 } 3711 3712 Pred = processLeaks(state, Leaked, C, Pred); 3713 3714 // Did we cache out? 3715 if (!Pred) 3716 return; 3717 3718 // Now generate a new node that nukes the old bindings. 3719 // The only bindings left at this point are the leaked symbols. 3720 RefBindingsTy::Factory &F = state->get_context<RefBindings>(); 3721 B = state->get<RefBindings>(); 3722 3723 for (SmallVectorImpl<SymbolRef>::iterator I = Leaked.begin(), 3724 E = Leaked.end(); 3725 I != E; ++I) 3726 B = F.remove(B, *I); 3727 3728 state = state->set<RefBindings>(B); 3729 C.addTransition(state, Pred); 3730 } 3731 3732 void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3733 const char *NL, const char *Sep) const { 3734 3735 RefBindingsTy B = State->get<RefBindings>(); 3736 3737 if (B.isEmpty()) 3738 return; 3739 3740 Out << Sep << NL; 3741 3742 for (RefBindingsTy::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3743 Out << I->first << " : "; 3744 I->second.print(Out); 3745 Out << NL; 3746 } 3747 } 3748 3749 //===----------------------------------------------------------------------===// 3750 // Checker registration. 3751 //===----------------------------------------------------------------------===// 3752 3753 void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3754 Mgr.registerChecker<RetainCountChecker>(Mgr.getAnalyzerOptions()); 3755 } 3756 3757