RetainCountChecker.cpp revision f345ffb2f4e75e7837d9fba8745525b36fa92ee5
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/DeclObjC.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/Basic/LangOptions.h" 19#include "clang/Basic/SourceManager.h" 20#include "clang/Analysis/DomainSpecific/CocoaConventions.h" 21#include "clang/AST/ParentMap.h" 22#include "clang/StaticAnalyzer/Core/Checker.h" 23#include "clang/StaticAnalyzer/Core/CheckerManager.h" 24#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 25#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 26#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 30#include "llvm/ADT/DenseMap.h" 31#include "llvm/ADT/FoldingSet.h" 32#include "llvm/ADT/ImmutableList.h" 33#include "llvm/ADT/ImmutableMap.h" 34#include "llvm/ADT/SmallString.h" 35#include "llvm/ADT/STLExtras.h" 36#include "llvm/ADT/StringExtras.h" 37#include <cstdarg> 38 39using namespace clang; 40using namespace ento; 41using llvm::StrInStrNoCase; 42 43namespace { 44/// Wrapper around different kinds of node builder, so that helper functions 45/// can have a common interface. 46class GenericNodeBuilderRefCount { 47 CheckerContext *C; 48 const ProgramPointTag *tag; 49public: 50 GenericNodeBuilderRefCount(CheckerContext &c, 51 const ProgramPointTag *t = 0) 52 : C(&c), tag(t){} 53 54 ExplodedNode *MakeNode(ProgramStateRef state, ExplodedNode *Pred, 55 bool MarkAsSink = false) { 56 return C->addTransition(state, Pred, tag, MarkAsSink); 57 } 58}; 59} // end anonymous namespace 60 61//===----------------------------------------------------------------------===// 62// Primitives used for constructing summaries for function/method calls. 63//===----------------------------------------------------------------------===// 64 65/// ArgEffect is used to summarize a function/method call's effect on a 66/// particular argument. 67enum ArgEffect { DoNothing, Autorelease, Dealloc, DecRef, DecRefMsg, 68 DecRefBridgedTransfered, 69 DecRefAndStopTracking, DecRefMsgAndStopTracking, 70 IncRefMsg, IncRef, MakeCollectable, MayEscape, 71 NewAutoreleasePool, StopTracking }; 72 73namespace llvm { 74template <> struct FoldingSetTrait<ArgEffect> { 75static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 76 ID.AddInteger((unsigned) X); 77} 78}; 79} // end llvm namespace 80 81/// ArgEffects summarizes the effects of a function/method call on all of 82/// its arguments. 83typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 84 85namespace { 86 87/// RetEffect is used to summarize a function/method call's behavior with 88/// respect to its return value. 89class RetEffect { 90public: 91 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 92 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 93 OwnedWhenTrackedReceiver }; 94 95 enum ObjKind { CF, ObjC, AnyObj }; 96 97private: 98 Kind K; 99 ObjKind O; 100 101 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 102 103public: 104 Kind getKind() const { return K; } 105 106 ObjKind getObjKind() const { return O; } 107 108 bool isOwned() const { 109 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 110 K == OwnedWhenTrackedReceiver; 111 } 112 113 bool operator==(const RetEffect &Other) const { 114 return K == Other.K && O == Other.O; 115 } 116 117 static RetEffect MakeOwnedWhenTrackedReceiver() { 118 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 119 } 120 121 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 122 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 123 } 124 static RetEffect MakeNotOwned(ObjKind o) { 125 return RetEffect(NotOwnedSymbol, o); 126 } 127 static RetEffect MakeGCNotOwned() { 128 return RetEffect(GCNotOwnedSymbol, ObjC); 129 } 130 static RetEffect MakeARCNotOwned() { 131 return RetEffect(ARCNotOwnedSymbol, ObjC); 132 } 133 static RetEffect MakeNoRet() { 134 return RetEffect(NoRet); 135 } 136 137 void Profile(llvm::FoldingSetNodeID& ID) const { 138 ID.AddInteger((unsigned) K); 139 ID.AddInteger((unsigned) O); 140 } 141}; 142 143//===----------------------------------------------------------------------===// 144// Reference-counting logic (typestate + counts). 145//===----------------------------------------------------------------------===// 146 147class RefVal { 148public: 149 enum Kind { 150 Owned = 0, // Owning reference. 151 NotOwned, // Reference is not owned by still valid (not freed). 152 Released, // Object has been released. 153 ReturnedOwned, // Returned object passes ownership to caller. 154 ReturnedNotOwned, // Return object does not pass ownership to caller. 155 ERROR_START, 156 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 157 ErrorDeallocGC, // Calling -dealloc with GC enabled. 158 ErrorUseAfterRelease, // Object used after released. 159 ErrorReleaseNotOwned, // Release of an object that was not owned. 160 ERROR_LEAK_START, 161 ErrorLeak, // A memory leak due to excessive reference counts. 162 ErrorLeakReturned, // A memory leak due to the returning method not having 163 // the correct naming conventions. 164 ErrorGCLeakReturned, 165 ErrorOverAutorelease, 166 ErrorReturnedNotOwned 167 }; 168 169private: 170 Kind kind; 171 RetEffect::ObjKind okind; 172 unsigned Cnt; 173 unsigned ACnt; 174 QualType T; 175 176 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 177 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 178 179public: 180 Kind getKind() const { return kind; } 181 182 RetEffect::ObjKind getObjKind() const { return okind; } 183 184 unsigned getCount() const { return Cnt; } 185 unsigned getAutoreleaseCount() const { return ACnt; } 186 unsigned getCombinedCounts() const { return Cnt + ACnt; } 187 void clearCounts() { Cnt = 0; ACnt = 0; } 188 void setCount(unsigned i) { Cnt = i; } 189 void setAutoreleaseCount(unsigned i) { ACnt = i; } 190 191 QualType getType() const { return T; } 192 193 bool isOwned() const { 194 return getKind() == Owned; 195 } 196 197 bool isNotOwned() const { 198 return getKind() == NotOwned; 199 } 200 201 bool isReturnedOwned() const { 202 return getKind() == ReturnedOwned; 203 } 204 205 bool isReturnedNotOwned() const { 206 return getKind() == ReturnedNotOwned; 207 } 208 209 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 210 unsigned Count = 1) { 211 return RefVal(Owned, o, Count, 0, t); 212 } 213 214 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 215 unsigned Count = 0) { 216 return RefVal(NotOwned, o, Count, 0, t); 217 } 218 219 // Comparison, profiling, and pretty-printing. 220 221 bool operator==(const RefVal& X) const { 222 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 223 } 224 225 RefVal operator-(size_t i) const { 226 return RefVal(getKind(), getObjKind(), getCount() - i, 227 getAutoreleaseCount(), getType()); 228 } 229 230 RefVal operator+(size_t i) const { 231 return RefVal(getKind(), getObjKind(), getCount() + i, 232 getAutoreleaseCount(), getType()); 233 } 234 235 RefVal operator^(Kind k) const { 236 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 237 getType()); 238 } 239 240 RefVal autorelease() const { 241 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 242 getType()); 243 } 244 245 void Profile(llvm::FoldingSetNodeID& ID) const { 246 ID.AddInteger((unsigned) kind); 247 ID.AddInteger(Cnt); 248 ID.AddInteger(ACnt); 249 ID.Add(T); 250 } 251 252 void print(raw_ostream &Out) const; 253}; 254 255void RefVal::print(raw_ostream &Out) const { 256 if (!T.isNull()) 257 Out << "Tracked " << T.getAsString() << '/'; 258 259 switch (getKind()) { 260 default: llvm_unreachable("Invalid RefVal kind"); 261 case Owned: { 262 Out << "Owned"; 263 unsigned cnt = getCount(); 264 if (cnt) Out << " (+ " << cnt << ")"; 265 break; 266 } 267 268 case NotOwned: { 269 Out << "NotOwned"; 270 unsigned cnt = getCount(); 271 if (cnt) Out << " (+ " << cnt << ")"; 272 break; 273 } 274 275 case ReturnedOwned: { 276 Out << "ReturnedOwned"; 277 unsigned cnt = getCount(); 278 if (cnt) Out << " (+ " << cnt << ")"; 279 break; 280 } 281 282 case ReturnedNotOwned: { 283 Out << "ReturnedNotOwned"; 284 unsigned cnt = getCount(); 285 if (cnt) Out << " (+ " << cnt << ")"; 286 break; 287 } 288 289 case Released: 290 Out << "Released"; 291 break; 292 293 case ErrorDeallocGC: 294 Out << "-dealloc (GC)"; 295 break; 296 297 case ErrorDeallocNotOwned: 298 Out << "-dealloc (not-owned)"; 299 break; 300 301 case ErrorLeak: 302 Out << "Leaked"; 303 break; 304 305 case ErrorLeakReturned: 306 Out << "Leaked (Bad naming)"; 307 break; 308 309 case ErrorGCLeakReturned: 310 Out << "Leaked (GC-ed at return)"; 311 break; 312 313 case ErrorUseAfterRelease: 314 Out << "Use-After-Release [ERROR]"; 315 break; 316 317 case ErrorReleaseNotOwned: 318 Out << "Release of Not-Owned [ERROR]"; 319 break; 320 321 case RefVal::ErrorOverAutorelease: 322 Out << "Over autoreleased"; 323 break; 324 325 case RefVal::ErrorReturnedNotOwned: 326 Out << "Non-owned object returned instead of owned"; 327 break; 328 } 329 330 if (ACnt) { 331 Out << " [ARC +" << ACnt << ']'; 332 } 333} 334} //end anonymous namespace 335 336//===----------------------------------------------------------------------===// 337// RefBindings - State used to track object reference counts. 338//===----------------------------------------------------------------------===// 339 340typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 341 342namespace clang { 343namespace ento { 344template<> 345struct ProgramStateTrait<RefBindings> 346 : public ProgramStatePartialTrait<RefBindings> { 347 static void *GDMIndex() { 348 static int RefBIndex = 0; 349 return &RefBIndex; 350 } 351}; 352} 353} 354 355static inline const RefVal *getRefBinding(ProgramStateRef State, 356 SymbolRef Sym) { 357 return State->get<RefBindings>(Sym); 358} 359 360static inline ProgramStateRef setRefBinding(ProgramStateRef State, 361 SymbolRef Sym, RefVal Val) { 362 return State->set<RefBindings>(Sym, Val); 363} 364 365static ProgramStateRef removeRefBinding(ProgramStateRef State, SymbolRef Sym) { 366 return State->remove<RefBindings>(Sym); 367} 368 369//===----------------------------------------------------------------------===// 370// Function/Method behavior summaries. 371//===----------------------------------------------------------------------===// 372 373namespace { 374class RetainSummary { 375 /// Args - a map of (index, ArgEffect) pairs, where index 376 /// specifies the argument (starting from 0). This can be sparsely 377 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 378 ArgEffects Args; 379 380 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 381 /// do not have an entry in Args. 382 ArgEffect DefaultArgEffect; 383 384 /// Receiver - If this summary applies to an Objective-C message expression, 385 /// this is the effect applied to the state of the receiver. 386 ArgEffect Receiver; 387 388 /// Ret - The effect on the return value. Used to indicate if the 389 /// function/method call returns a new tracked symbol. 390 RetEffect Ret; 391 392public: 393 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 394 ArgEffect ReceiverEff) 395 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 396 397 /// getArg - Return the argument effect on the argument specified by 398 /// idx (starting from 0). 399 ArgEffect getArg(unsigned idx) const { 400 if (const ArgEffect *AE = Args.lookup(idx)) 401 return *AE; 402 403 return DefaultArgEffect; 404 } 405 406 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 407 Args = af.add(Args, idx, e); 408 } 409 410 /// setDefaultArgEffect - Set the default argument effect. 411 void setDefaultArgEffect(ArgEffect E) { 412 DefaultArgEffect = E; 413 } 414 415 /// getRetEffect - Returns the effect on the return value of the call. 416 RetEffect getRetEffect() const { return Ret; } 417 418 /// setRetEffect - Set the effect of the return value of the call. 419 void setRetEffect(RetEffect E) { Ret = E; } 420 421 422 /// Sets the effect on the receiver of the message. 423 void setReceiverEffect(ArgEffect e) { Receiver = e; } 424 425 /// getReceiverEffect - Returns the effect on the receiver of the call. 426 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 427 ArgEffect getReceiverEffect() const { return Receiver; } 428 429 /// Test if two retain summaries are identical. Note that merely equivalent 430 /// summaries are not necessarily identical (for example, if an explicit 431 /// argument effect matches the default effect). 432 bool operator==(const RetainSummary &Other) const { 433 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 434 Receiver == Other.Receiver && Ret == Other.Ret; 435 } 436 437 /// Profile this summary for inclusion in a FoldingSet. 438 void Profile(llvm::FoldingSetNodeID& ID) const { 439 ID.Add(Args); 440 ID.Add(DefaultArgEffect); 441 ID.Add(Receiver); 442 ID.Add(Ret); 443 } 444 445 /// A retain summary is simple if it has no ArgEffects other than the default. 446 bool isSimple() const { 447 return Args.isEmpty(); 448 } 449 450private: 451 ArgEffects getArgEffects() const { return Args; } 452 ArgEffect getDefaultArgEffect() const { return DefaultArgEffect; } 453 454 friend class RetainSummaryManager; 455}; 456} // end anonymous namespace 457 458//===----------------------------------------------------------------------===// 459// Data structures for constructing summaries. 460//===----------------------------------------------------------------------===// 461 462namespace { 463class ObjCSummaryKey { 464 IdentifierInfo* II; 465 Selector S; 466public: 467 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 468 : II(ii), S(s) {} 469 470 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 471 : II(d ? d->getIdentifier() : 0), S(s) {} 472 473 ObjCSummaryKey(Selector s) 474 : II(0), S(s) {} 475 476 IdentifierInfo *getIdentifier() const { return II; } 477 Selector getSelector() const { return S; } 478}; 479} 480 481namespace llvm { 482template <> struct DenseMapInfo<ObjCSummaryKey> { 483 static inline ObjCSummaryKey getEmptyKey() { 484 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 485 DenseMapInfo<Selector>::getEmptyKey()); 486 } 487 488 static inline ObjCSummaryKey getTombstoneKey() { 489 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 490 DenseMapInfo<Selector>::getTombstoneKey()); 491 } 492 493 static unsigned getHashValue(const ObjCSummaryKey &V) { 494 typedef std::pair<IdentifierInfo*, Selector> PairTy; 495 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 496 V.getSelector())); 497 } 498 499 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 500 return LHS.getIdentifier() == RHS.getIdentifier() && 501 LHS.getSelector() == RHS.getSelector(); 502 } 503 504}; 505template <> 506struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 507} // end llvm namespace 508 509namespace { 510class ObjCSummaryCache { 511 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 512 MapTy M; 513public: 514 ObjCSummaryCache() {} 515 516 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 517 // Do a lookup with the (D,S) pair. If we find a match return 518 // the iterator. 519 ObjCSummaryKey K(D, S); 520 MapTy::iterator I = M.find(K); 521 522 if (I != M.end()) 523 return I->second; 524 if (!D) 525 return NULL; 526 527 // Walk the super chain. If we find a hit with a parent, we'll end 528 // up returning that summary. We actually allow that key (null,S), as 529 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 530 // generate initial summaries without having to worry about NSObject 531 // being declared. 532 // FIXME: We may change this at some point. 533 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 534 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 535 break; 536 537 if (!C) 538 return NULL; 539 } 540 541 // Cache the summary with original key to make the next lookup faster 542 // and return the iterator. 543 const RetainSummary *Summ = I->second; 544 M[K] = Summ; 545 return Summ; 546 } 547 548 const RetainSummary *find(IdentifierInfo* II, Selector S) { 549 // FIXME: Class method lookup. Right now we dont' have a good way 550 // of going between IdentifierInfo* and the class hierarchy. 551 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 552 553 if (I == M.end()) 554 I = M.find(ObjCSummaryKey(S)); 555 556 return I == M.end() ? NULL : I->second; 557 } 558 559 const RetainSummary *& operator[](ObjCSummaryKey K) { 560 return M[K]; 561 } 562 563 const RetainSummary *& operator[](Selector S) { 564 return M[ ObjCSummaryKey(S) ]; 565 } 566}; 567} // end anonymous namespace 568 569//===----------------------------------------------------------------------===// 570// Data structures for managing collections of summaries. 571//===----------------------------------------------------------------------===// 572 573namespace { 574class RetainSummaryManager { 575 576 //==-----------------------------------------------------------------==// 577 // Typedefs. 578 //==-----------------------------------------------------------------==// 579 580 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 581 FuncSummariesTy; 582 583 typedef ObjCSummaryCache ObjCMethodSummariesTy; 584 585 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 586 587 //==-----------------------------------------------------------------==// 588 // Data. 589 //==-----------------------------------------------------------------==// 590 591 /// Ctx - The ASTContext object for the analyzed ASTs. 592 ASTContext &Ctx; 593 594 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 595 const bool GCEnabled; 596 597 /// Records whether or not the analyzed code runs in ARC mode. 598 const bool ARCEnabled; 599 600 /// FuncSummaries - A map from FunctionDecls to summaries. 601 FuncSummariesTy FuncSummaries; 602 603 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 604 /// to summaries. 605 ObjCMethodSummariesTy ObjCClassMethodSummaries; 606 607 /// ObjCMethodSummaries - A map from selectors to summaries. 608 ObjCMethodSummariesTy ObjCMethodSummaries; 609 610 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 611 /// and all other data used by the checker. 612 llvm::BumpPtrAllocator BPAlloc; 613 614 /// AF - A factory for ArgEffects objects. 615 ArgEffects::Factory AF; 616 617 /// ScratchArgs - A holding buffer for construct ArgEffects. 618 ArgEffects ScratchArgs; 619 620 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 621 /// objects. 622 RetEffect ObjCAllocRetE; 623 624 /// ObjCInitRetE - Default return effect for init methods returning 625 /// Objective-C objects. 626 RetEffect ObjCInitRetE; 627 628 /// SimpleSummaries - Used for uniquing summaries that don't have special 629 /// effects. 630 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 631 632 //==-----------------------------------------------------------------==// 633 // Methods. 634 //==-----------------------------------------------------------------==// 635 636 /// getArgEffects - Returns a persistent ArgEffects object based on the 637 /// data in ScratchArgs. 638 ArgEffects getArgEffects(); 639 640 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 641 642 const RetainSummary *getUnarySummary(const FunctionType* FT, 643 UnaryFuncKind func); 644 645 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 646 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 647 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 648 649 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 650 651 const RetainSummary *getPersistentSummary(RetEffect RetEff, 652 ArgEffect ReceiverEff = DoNothing, 653 ArgEffect DefaultEff = MayEscape) { 654 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 655 return getPersistentSummary(Summ); 656 } 657 658 const RetainSummary *getDoNothingSummary() { 659 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 660 } 661 662 const RetainSummary *getDefaultSummary() { 663 return getPersistentSummary(RetEffect::MakeNoRet(), 664 DoNothing, MayEscape); 665 } 666 667 const RetainSummary *getPersistentStopSummary() { 668 return getPersistentSummary(RetEffect::MakeNoRet(), 669 StopTracking, StopTracking); 670 } 671 672 void InitializeClassMethodSummaries(); 673 void InitializeMethodSummaries(); 674private: 675 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 676 ObjCClassMethodSummaries[S] = Summ; 677 } 678 679 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 680 ObjCMethodSummaries[S] = Summ; 681 } 682 683 void addClassMethSummary(const char* Cls, const char* name, 684 const RetainSummary *Summ, bool isNullary = true) { 685 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 686 Selector S = isNullary ? GetNullarySelector(name, Ctx) 687 : GetUnarySelector(name, Ctx); 688 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 689 } 690 691 void addInstMethSummary(const char* Cls, const char* nullaryName, 692 const RetainSummary *Summ) { 693 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 694 Selector S = GetNullarySelector(nullaryName, Ctx); 695 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 696 } 697 698 Selector generateSelector(va_list argp) { 699 SmallVector<IdentifierInfo*, 10> II; 700 701 while (const char* s = va_arg(argp, const char*)) 702 II.push_back(&Ctx.Idents.get(s)); 703 704 return Ctx.Selectors.getSelector(II.size(), &II[0]); 705 } 706 707 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 708 const RetainSummary * Summ, va_list argp) { 709 Selector S = generateSelector(argp); 710 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 711 } 712 713 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 714 va_list argp; 715 va_start(argp, Summ); 716 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 717 va_end(argp); 718 } 719 720 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 721 va_list argp; 722 va_start(argp, Summ); 723 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 724 va_end(argp); 725 } 726 727 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 728 va_list argp; 729 va_start(argp, Summ); 730 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 731 va_end(argp); 732 } 733 734public: 735 736 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 737 : Ctx(ctx), 738 GCEnabled(gcenabled), 739 ARCEnabled(usesARC), 740 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 741 ObjCAllocRetE(gcenabled 742 ? RetEffect::MakeGCNotOwned() 743 : (usesARC ? RetEffect::MakeARCNotOwned() 744 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 745 ObjCInitRetE(gcenabled 746 ? RetEffect::MakeGCNotOwned() 747 : (usesARC ? RetEffect::MakeARCNotOwned() 748 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 749 InitializeClassMethodSummaries(); 750 InitializeMethodSummaries(); 751 } 752 753 const RetainSummary *getSummary(const CallEvent &Call, 754 ProgramStateRef State = 0); 755 756 const RetainSummary *getFunctionSummary(const FunctionDecl *FD); 757 758 const RetainSummary *getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 759 const ObjCMethodDecl *MD, 760 QualType RetTy, 761 ObjCMethodSummariesTy &CachedSummaries); 762 763 const RetainSummary *getInstanceMethodSummary(const ObjCMethodCall &M, 764 ProgramStateRef State); 765 766 const RetainSummary *getClassMethodSummary(const ObjCMethodCall &M) { 767 assert(!M.isInstanceMessage()); 768 const ObjCInterfaceDecl *Class = M.getReceiverInterface(); 769 770 return getMethodSummary(M.getSelector(), Class, M.getDecl(), 771 M.getResultType(), ObjCClassMethodSummaries); 772 } 773 774 /// getMethodSummary - This version of getMethodSummary is used to query 775 /// the summary for the current method being analyzed. 776 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 777 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 778 Selector S = MD->getSelector(); 779 QualType ResultTy = MD->getResultType(); 780 781 ObjCMethodSummariesTy *CachedSummaries; 782 if (MD->isInstanceMethod()) 783 CachedSummaries = &ObjCMethodSummaries; 784 else 785 CachedSummaries = &ObjCClassMethodSummaries; 786 787 return getMethodSummary(S, ID, MD, ResultTy, *CachedSummaries); 788 } 789 790 const RetainSummary *getStandardMethodSummary(const ObjCMethodDecl *MD, 791 Selector S, QualType RetTy); 792 793 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 794 const ObjCMethodDecl *MD); 795 796 void updateSummaryFromAnnotations(const RetainSummary *&Summ, 797 const FunctionDecl *FD); 798 799 void updateSummaryForCall(const RetainSummary *&Summ, 800 const CallEvent &Call); 801 802 bool isGCEnabled() const { return GCEnabled; } 803 804 bool isARCEnabled() const { return ARCEnabled; } 805 806 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 807 808 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 809 810 friend class RetainSummaryTemplate; 811}; 812 813// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 814// summaries. If a function or method looks like it has a default summary, but 815// it has annotations, the annotations are added to the stack-based template 816// and then copied into managed memory. 817class RetainSummaryTemplate { 818 RetainSummaryManager &Manager; 819 const RetainSummary *&RealSummary; 820 RetainSummary ScratchSummary; 821 bool Accessed; 822public: 823 RetainSummaryTemplate(const RetainSummary *&real, RetainSummaryManager &mgr) 824 : Manager(mgr), RealSummary(real), ScratchSummary(*real), Accessed(false) {} 825 826 ~RetainSummaryTemplate() { 827 if (Accessed) 828 RealSummary = Manager.getPersistentSummary(ScratchSummary); 829 } 830 831 RetainSummary &operator*() { 832 Accessed = true; 833 return ScratchSummary; 834 } 835 836 RetainSummary *operator->() { 837 Accessed = true; 838 return &ScratchSummary; 839 } 840}; 841 842} // end anonymous namespace 843 844//===----------------------------------------------------------------------===// 845// Implementation of checker data structures. 846//===----------------------------------------------------------------------===// 847 848ArgEffects RetainSummaryManager::getArgEffects() { 849 ArgEffects AE = ScratchArgs; 850 ScratchArgs = AF.getEmptyMap(); 851 return AE; 852} 853 854const RetainSummary * 855RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 856 // Unique "simple" summaries -- those without ArgEffects. 857 if (OldSumm.isSimple()) { 858 llvm::FoldingSetNodeID ID; 859 OldSumm.Profile(ID); 860 861 void *Pos; 862 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 863 864 if (!N) { 865 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 866 new (N) CachedSummaryNode(OldSumm); 867 SimpleSummaries.InsertNode(N, Pos); 868 } 869 870 return &N->getValue(); 871 } 872 873 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 874 new (Summ) RetainSummary(OldSumm); 875 return Summ; 876} 877 878//===----------------------------------------------------------------------===// 879// Summary creation for functions (largely uses of Core Foundation). 880//===----------------------------------------------------------------------===// 881 882static bool isRetain(const FunctionDecl *FD, StringRef FName) { 883 return FName.endswith("Retain"); 884} 885 886static bool isRelease(const FunctionDecl *FD, StringRef FName) { 887 return FName.endswith("Release"); 888} 889 890static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 891 // FIXME: Remove FunctionDecl parameter. 892 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 893 return FName.find("MakeCollectable") != StringRef::npos; 894} 895 896static ArgEffect getStopTrackingEquivalent(ArgEffect E) { 897 switch (E) { 898 case DoNothing: 899 case Autorelease: 900 case DecRefBridgedTransfered: 901 case IncRef: 902 case IncRefMsg: 903 case MakeCollectable: 904 case MayEscape: 905 case NewAutoreleasePool: 906 case StopTracking: 907 return StopTracking; 908 case DecRef: 909 case DecRefAndStopTracking: 910 return DecRefAndStopTracking; 911 case DecRefMsg: 912 case DecRefMsgAndStopTracking: 913 return DecRefMsgAndStopTracking; 914 case Dealloc: 915 return Dealloc; 916 } 917 918 llvm_unreachable("Unknown ArgEffect kind"); 919} 920 921void RetainSummaryManager::updateSummaryForCall(const RetainSummary *&S, 922 const CallEvent &Call) { 923 if (Call.hasNonZeroCallbackArg()) { 924 ArgEffect RecEffect = getStopTrackingEquivalent(S->getReceiverEffect()); 925 ArgEffect DefEffect = getStopTrackingEquivalent(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 = getStopTrackingEquivalent(I->second); 932 if (Translated != DefEffect) 933 ScratchArgs = AF.add(ScratchArgs, I->first, Translated); 934 } 935 936 RetEffect RE = RetEffect::MakeNoRet(); 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 IdentifierInfo *Name = FC->getDecl()->getIdentifier(); 943 944 // This callback frees the associated buffer. 945 if (Name->isStr("CGBitmapContextCreateWithData")) 946 RE = S->getRetEffect(); 947 } 948 949 S = getPersistentSummary(RE, RecEffect, DefEffect); 950 } 951} 952 953const RetainSummary * 954RetainSummaryManager::getSummary(const CallEvent &Call, 955 ProgramStateRef State) { 956 const RetainSummary *Summ; 957 switch (Call.getKind()) { 958 case CE_Function: 959 Summ = getFunctionSummary(cast<FunctionCall>(Call).getDecl()); 960 break; 961 case CE_CXXMember: 962 case CE_CXXMemberOperator: 963 case CE_Block: 964 case CE_CXXConstructor: 965 case CE_CXXDestructor: 966 case CE_CXXAllocator: 967 // FIXME: These calls are currently unsupported. 968 return getPersistentStopSummary(); 969 case CE_ObjCMessage: { 970 const ObjCMethodCall &Msg = cast<ObjCMethodCall>(Call); 971 if (Msg.isInstanceMessage()) 972 Summ = getInstanceMethodSummary(Msg, State); 973 else 974 Summ = getClassMethodSummary(Msg); 975 break; 976 } 977 } 978 979 updateSummaryForCall(Summ, Call); 980 981 assert(Summ && "Unknown call type?"); 982 return Summ; 983} 984 985const RetainSummary * 986RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) { 987 // If we don't know what function we're calling, use our default summary. 988 if (!FD) 989 return getDefaultSummary(); 990 991 // Look up a summary in our cache of FunctionDecls -> Summaries. 992 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 993 if (I != FuncSummaries.end()) 994 return I->second; 995 996 // No summary? Generate one. 997 const RetainSummary *S = 0; 998 bool AllowAnnotations = true; 999 1000 do { 1001 // We generate "stop" summaries for implicitly defined functions. 1002 if (FD->isImplicit()) { 1003 S = getPersistentStopSummary(); 1004 break; 1005 } 1006 1007 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 1008 // function's type. 1009 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 1010 const IdentifierInfo *II = FD->getIdentifier(); 1011 if (!II) 1012 break; 1013 1014 StringRef FName = II->getName(); 1015 1016 // Strip away preceding '_'. Doing this here will effect all the checks 1017 // down below. 1018 FName = FName.substr(FName.find_first_not_of('_')); 1019 1020 // Inspect the result type. 1021 QualType RetTy = FT->getResultType(); 1022 1023 // FIXME: This should all be refactored into a chain of "summary lookup" 1024 // filters. 1025 assert(ScratchArgs.isEmpty()); 1026 1027 if (FName == "pthread_create" || FName == "pthread_setspecific") { 1028 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 1029 // This will be addressed better with IPA. 1030 S = getPersistentStopSummary(); 1031 } else if (FName == "NSMakeCollectable") { 1032 // Handle: id NSMakeCollectable(CFTypeRef) 1033 S = (RetTy->isObjCIdType()) 1034 ? getUnarySummary(FT, cfmakecollectable) 1035 : getPersistentStopSummary(); 1036 // The headers on OS X 10.8 use cf_consumed/ns_returns_retained, 1037 // but we can fully model NSMakeCollectable ourselves. 1038 AllowAnnotations = false; 1039 } else if (FName == "IOBSDNameMatching" || 1040 FName == "IOServiceMatching" || 1041 FName == "IOServiceNameMatching" || 1042 FName == "IORegistryEntrySearchCFProperty" || 1043 FName == "IORegistryEntryIDMatching" || 1044 FName == "IOOpenFirmwarePathMatching") { 1045 // Part of <rdar://problem/6961230>. (IOKit) 1046 // This should be addressed using a API table. 1047 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1048 DoNothing, DoNothing); 1049 } else if (FName == "IOServiceGetMatchingService" || 1050 FName == "IOServiceGetMatchingServices") { 1051 // FIXES: <rdar://problem/6326900> 1052 // This should be addressed using a API table. This strcmp is also 1053 // a little gross, but there is no need to super optimize here. 1054 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 1055 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1056 } else if (FName == "IOServiceAddNotification" || 1057 FName == "IOServiceAddMatchingNotification") { 1058 // Part of <rdar://problem/6961230>. (IOKit) 1059 // This should be addressed using a API table. 1060 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 1061 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1062 } else if (FName == "CVPixelBufferCreateWithBytes") { 1063 // FIXES: <rdar://problem/7283567> 1064 // Eventually this can be improved by recognizing that the pixel 1065 // buffer passed to CVPixelBufferCreateWithBytes is released via 1066 // a callback and doing full IPA to make sure this is done correctly. 1067 // FIXME: This function has an out parameter that returns an 1068 // allocated object. 1069 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 1070 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1071 } else if (FName == "CGBitmapContextCreateWithData") { 1072 // FIXES: <rdar://problem/7358899> 1073 // Eventually this can be improved by recognizing that 'releaseInfo' 1074 // passed to CGBitmapContextCreateWithData is released via 1075 // a callback and doing full IPA to make sure this is done correctly. 1076 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 1077 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 1078 DoNothing, DoNothing); 1079 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 1080 // FIXES: <rdar://problem/7283567> 1081 // Eventually this can be improved by recognizing that the pixel 1082 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 1083 // via a callback and doing full IPA to make sure this is done 1084 // correctly. 1085 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 1086 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1087 } else if (FName == "dispatch_set_context") { 1088 // <rdar://problem/11059275> - The analyzer currently doesn't have 1089 // a good way to reason about the finalizer function for libdispatch. 1090 // If we pass a context object that is memory managed, stop tracking it. 1091 // FIXME: this hack should possibly go away once we can handle 1092 // libdispatch finalizers. 1093 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1094 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1095 } else if (FName.startswith("NSLog")) { 1096 S = getDoNothingSummary(); 1097 } else if (FName.startswith("NS") && 1098 (FName.find("Insert") != StringRef::npos)) { 1099 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1100 // be deallocated by NSMapRemove. (radar://11152419) 1101 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1102 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1103 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1104 } 1105 1106 // Did we get a summary? 1107 if (S) 1108 break; 1109 1110 // Enable this code once the semantics of NSDeallocateObject are resolved 1111 // for GC. <rdar://problem/6619988> 1112#if 0 1113 // Handle: NSDeallocateObject(id anObject); 1114 // This method does allow 'nil' (although we don't check it now). 1115 if (strcmp(FName, "NSDeallocateObject") == 0) { 1116 return RetTy == Ctx.VoidTy 1117 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 1118 : getPersistentStopSummary(); 1119 } 1120#endif 1121 1122 if (RetTy->isPointerType()) { 1123 // For CoreFoundation ('CF') types. 1124 if (cocoa::isRefType(RetTy, "CF", FName)) { 1125 if (isRetain(FD, FName)) 1126 S = getUnarySummary(FT, cfretain); 1127 else if (isMakeCollectable(FD, FName)) 1128 S = getUnarySummary(FT, cfmakecollectable); 1129 else 1130 S = getCFCreateGetRuleSummary(FD); 1131 1132 break; 1133 } 1134 1135 // For CoreGraphics ('CG') types. 1136 if (cocoa::isRefType(RetTy, "CG", FName)) { 1137 if (isRetain(FD, FName)) 1138 S = getUnarySummary(FT, cfretain); 1139 else 1140 S = getCFCreateGetRuleSummary(FD); 1141 1142 break; 1143 } 1144 1145 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1146 if (cocoa::isRefType(RetTy, "DADisk") || 1147 cocoa::isRefType(RetTy, "DADissenter") || 1148 cocoa::isRefType(RetTy, "DASessionRef")) { 1149 S = getCFCreateGetRuleSummary(FD); 1150 break; 1151 } 1152 1153 break; 1154 } 1155 1156 // Check for release functions, the only kind of functions that we care 1157 // about that don't return a pointer type. 1158 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1159 // Test for 'CGCF'. 1160 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1161 1162 if (isRelease(FD, FName)) 1163 S = getUnarySummary(FT, cfrelease); 1164 else { 1165 assert (ScratchArgs.isEmpty()); 1166 // Remaining CoreFoundation and CoreGraphics functions. 1167 // We use to assume that they all strictly followed the ownership idiom 1168 // and that ownership cannot be transferred. While this is technically 1169 // correct, many methods allow a tracked object to escape. For example: 1170 // 1171 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1172 // CFDictionaryAddValue(y, key, x); 1173 // CFRelease(x); 1174 // ... it is okay to use 'x' since 'y' has a reference to it 1175 // 1176 // We handle this and similar cases with the follow heuristic. If the 1177 // function name contains "InsertValue", "SetValue", "AddValue", 1178 // "AppendValue", or "SetAttribute", then we assume that arguments may 1179 // "escape." This means that something else holds on to the object, 1180 // allowing it be used even after its local retain count drops to 0. 1181 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1182 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1183 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1184 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1185 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1186 ? MayEscape : DoNothing; 1187 1188 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1189 } 1190 } 1191 } 1192 while (0); 1193 1194 // If we got all the way here without any luck, use a default summary. 1195 if (!S) 1196 S = getDefaultSummary(); 1197 1198 // Annotations override defaults. 1199 if (AllowAnnotations) 1200 updateSummaryFromAnnotations(S, FD); 1201 1202 FuncSummaries[FD] = S; 1203 return S; 1204} 1205 1206const RetainSummary * 1207RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1208 if (coreFoundation::followsCreateRule(FD)) 1209 return getCFSummaryCreateRule(FD); 1210 1211 return getCFSummaryGetRule(FD); 1212} 1213 1214const RetainSummary * 1215RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1216 UnaryFuncKind func) { 1217 1218 // Sanity check that this is *really* a unary function. This can 1219 // happen if people do weird things. 1220 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1221 if (!FTP || FTP->getNumArgs() != 1) 1222 return getPersistentStopSummary(); 1223 1224 assert (ScratchArgs.isEmpty()); 1225 1226 ArgEffect Effect; 1227 switch (func) { 1228 case cfretain: Effect = IncRef; break; 1229 case cfrelease: Effect = DecRef; break; 1230 case cfmakecollectable: Effect = MakeCollectable; break; 1231 } 1232 1233 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1234 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1235} 1236 1237const RetainSummary * 1238RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1239 assert (ScratchArgs.isEmpty()); 1240 1241 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1242} 1243 1244const RetainSummary * 1245RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1246 assert (ScratchArgs.isEmpty()); 1247 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1248 DoNothing, DoNothing); 1249} 1250 1251//===----------------------------------------------------------------------===// 1252// Summary creation for Selectors. 1253//===----------------------------------------------------------------------===// 1254 1255void 1256RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1257 const FunctionDecl *FD) { 1258 if (!FD) 1259 return; 1260 1261 assert(Summ && "Must have a summary to add annotations to."); 1262 RetainSummaryTemplate Template(Summ, *this); 1263 1264 // Effects on the parameters. 1265 unsigned parm_idx = 0; 1266 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1267 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1268 const ParmVarDecl *pd = *pi; 1269 if (pd->getAttr<NSConsumedAttr>()) { 1270 if (!GCEnabled) { 1271 Template->addArg(AF, parm_idx, DecRef); 1272 } 1273 } else if (pd->getAttr<CFConsumedAttr>()) { 1274 Template->addArg(AF, parm_idx, DecRef); 1275 } 1276 } 1277 1278 QualType RetTy = FD->getResultType(); 1279 1280 // Determine if there is a special return effect for this method. 1281 if (cocoa::isCocoaObjectRef(RetTy)) { 1282 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1283 Template->setRetEffect(ObjCAllocRetE); 1284 } 1285 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1286 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1287 } 1288 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1289 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1290 } 1291 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1292 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1293 } 1294 } else if (RetTy->getAs<PointerType>()) { 1295 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1296 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1297 } 1298 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1299 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1300 } 1301 } 1302} 1303 1304void 1305RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1306 const ObjCMethodDecl *MD) { 1307 if (!MD) 1308 return; 1309 1310 assert(Summ && "Must have a valid summary to add annotations to"); 1311 RetainSummaryTemplate Template(Summ, *this); 1312 bool isTrackedLoc = false; 1313 1314 // Effects on the receiver. 1315 if (MD->getAttr<NSConsumesSelfAttr>()) { 1316 if (!GCEnabled) 1317 Template->setReceiverEffect(DecRefMsg); 1318 } 1319 1320 // Effects on the parameters. 1321 unsigned parm_idx = 0; 1322 for (ObjCMethodDecl::param_const_iterator 1323 pi=MD->param_begin(), pe=MD->param_end(); 1324 pi != pe; ++pi, ++parm_idx) { 1325 const ParmVarDecl *pd = *pi; 1326 if (pd->getAttr<NSConsumedAttr>()) { 1327 if (!GCEnabled) 1328 Template->addArg(AF, parm_idx, DecRef); 1329 } 1330 else if(pd->getAttr<CFConsumedAttr>()) { 1331 Template->addArg(AF, parm_idx, DecRef); 1332 } 1333 } 1334 1335 // Determine if there is a special return effect for this method. 1336 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1337 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1338 Template->setRetEffect(ObjCAllocRetE); 1339 return; 1340 } 1341 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1342 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1343 return; 1344 } 1345 1346 isTrackedLoc = true; 1347 } else { 1348 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1349 } 1350 1351 if (isTrackedLoc) { 1352 if (MD->getAttr<CFReturnsRetainedAttr>()) 1353 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1354 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1355 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1356 } 1357} 1358 1359const RetainSummary * 1360RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1361 Selector S, QualType RetTy) { 1362 1363 if (MD) { 1364 // Scan the method decl for 'void*' arguments. These should be treated 1365 // as 'StopTracking' because they are often used with delegates. 1366 // Delegates are a frequent form of false positives with the retain 1367 // count checker. 1368 unsigned i = 0; 1369 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1370 E = MD->param_end(); I != E; ++I, ++i) 1371 if (const ParmVarDecl *PD = *I) { 1372 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1373 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1374 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1375 } 1376 } 1377 1378 // Any special effects? 1379 ArgEffect ReceiverEff = DoNothing; 1380 RetEffect ResultEff = RetEffect::MakeNoRet(); 1381 1382 // Check the method family, and apply any default annotations. 1383 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1384 case OMF_None: 1385 case OMF_performSelector: 1386 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1387 // FIXME: Does the non-threaded performSelector family really belong here? 1388 // The selector could be, say, @selector(copy). 1389 if (cocoa::isCocoaObjectRef(RetTy)) 1390 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1391 else if (coreFoundation::isCFObjectRef(RetTy)) { 1392 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1393 // values for alloc, new, copy, or mutableCopy, so we have to 1394 // double-check with the selector. This is ugly, but there aren't that 1395 // many Objective-C methods that return CF objects, right? 1396 if (MD) { 1397 switch (S.getMethodFamily()) { 1398 case OMF_alloc: 1399 case OMF_new: 1400 case OMF_copy: 1401 case OMF_mutableCopy: 1402 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1403 break; 1404 default: 1405 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1406 break; 1407 } 1408 } else { 1409 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1410 } 1411 } 1412 break; 1413 case OMF_init: 1414 ResultEff = ObjCInitRetE; 1415 ReceiverEff = DecRefMsg; 1416 break; 1417 case OMF_alloc: 1418 case OMF_new: 1419 case OMF_copy: 1420 case OMF_mutableCopy: 1421 if (cocoa::isCocoaObjectRef(RetTy)) 1422 ResultEff = ObjCAllocRetE; 1423 else if (coreFoundation::isCFObjectRef(RetTy)) 1424 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1425 break; 1426 case OMF_autorelease: 1427 ReceiverEff = Autorelease; 1428 break; 1429 case OMF_retain: 1430 ReceiverEff = IncRefMsg; 1431 break; 1432 case OMF_release: 1433 ReceiverEff = DecRefMsg; 1434 break; 1435 case OMF_dealloc: 1436 ReceiverEff = Dealloc; 1437 break; 1438 case OMF_self: 1439 // -self is handled specially by the ExprEngine to propagate the receiver. 1440 break; 1441 case OMF_retainCount: 1442 case OMF_finalize: 1443 // These methods don't return objects. 1444 break; 1445 } 1446 1447 // If one of the arguments in the selector has the keyword 'delegate' we 1448 // should stop tracking the reference count for the receiver. This is 1449 // because the reference count is quite possibly handled by a delegate 1450 // method. 1451 if (S.isKeywordSelector()) { 1452 for (unsigned i = 0, e = S.getNumArgs(); i != e; ++i) { 1453 StringRef Slot = S.getNameForSlot(i); 1454 if (Slot.substr(Slot.size() - 8).equals_lower("delegate")) { 1455 if (ResultEff == ObjCInitRetE) 1456 ResultEff = RetEffect::MakeNoRet(); 1457 else 1458 ReceiverEff = StopTracking; 1459 } 1460 } 1461 } 1462 1463 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1464 ResultEff.getKind() == RetEffect::NoRet) 1465 return getDefaultSummary(); 1466 1467 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1468} 1469 1470const RetainSummary * 1471RetainSummaryManager::getInstanceMethodSummary(const ObjCMethodCall &Msg, 1472 ProgramStateRef State) { 1473 const ObjCInterfaceDecl *ReceiverClass = 0; 1474 1475 // We do better tracking of the type of the object than the core ExprEngine. 1476 // See if we have its type in our private state. 1477 // FIXME: Eventually replace the use of state->get<RefBindings> with 1478 // a generic API for reasoning about the Objective-C types of symbolic 1479 // objects. 1480 SVal ReceiverV = Msg.getReceiverSVal(); 1481 if (SymbolRef Sym = ReceiverV.getAsLocSymbol()) 1482 if (const RefVal *T = getRefBinding(State, Sym)) 1483 if (const ObjCObjectPointerType *PT = 1484 T->getType()->getAs<ObjCObjectPointerType>()) 1485 ReceiverClass = PT->getInterfaceDecl(); 1486 1487 // If we don't know what kind of object this is, fall back to its static type. 1488 if (!ReceiverClass) 1489 ReceiverClass = Msg.getReceiverInterface(); 1490 1491 // FIXME: The receiver could be a reference to a class, meaning that 1492 // we should use the class method. 1493 // id x = [NSObject class]; 1494 // [x performSelector:... withObject:... afterDelay:...]; 1495 Selector S = Msg.getSelector(); 1496 const ObjCMethodDecl *Method = Msg.getDecl(); 1497 if (!Method && ReceiverClass) 1498 Method = ReceiverClass->getInstanceMethod(S); 1499 1500 return getMethodSummary(S, ReceiverClass, Method, Msg.getResultType(), 1501 ObjCMethodSummaries); 1502} 1503 1504const RetainSummary * 1505RetainSummaryManager::getMethodSummary(Selector S, const ObjCInterfaceDecl *ID, 1506 const ObjCMethodDecl *MD, QualType RetTy, 1507 ObjCMethodSummariesTy &CachedSummaries) { 1508 1509 // Look up a summary in our summary cache. 1510 const RetainSummary *Summ = CachedSummaries.find(ID, S); 1511 1512 if (!Summ) { 1513 Summ = getStandardMethodSummary(MD, S, RetTy); 1514 1515 // Annotations override defaults. 1516 updateSummaryFromAnnotations(Summ, MD); 1517 1518 // Memoize the summary. 1519 CachedSummaries[ObjCSummaryKey(ID, S)] = Summ; 1520 } 1521 1522 return Summ; 1523} 1524 1525void RetainSummaryManager::InitializeClassMethodSummaries() { 1526 assert(ScratchArgs.isEmpty()); 1527 // Create the [NSAssertionHandler currentHander] summary. 1528 addClassMethSummary("NSAssertionHandler", "currentHandler", 1529 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1530 1531 // Create the [NSAutoreleasePool addObject:] summary. 1532 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1533 addClassMethSummary("NSAutoreleasePool", "addObject", 1534 getPersistentSummary(RetEffect::MakeNoRet(), 1535 DoNothing, Autorelease)); 1536} 1537 1538void RetainSummaryManager::InitializeMethodSummaries() { 1539 1540 assert (ScratchArgs.isEmpty()); 1541 1542 // Create the "init" selector. It just acts as a pass-through for the 1543 // receiver. 1544 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1545 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1546 1547 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1548 // claims the receiver and returns a retained object. 1549 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1550 InitSumm); 1551 1552 // The next methods are allocators. 1553 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1554 const RetainSummary *CFAllocSumm = 1555 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1556 1557 // Create the "retain" selector. 1558 RetEffect NoRet = RetEffect::MakeNoRet(); 1559 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1560 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1561 1562 // Create the "release" selector. 1563 Summ = getPersistentSummary(NoRet, DecRefMsg); 1564 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1565 1566 // Create the "drain" selector. 1567 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1568 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1569 1570 // Create the -dealloc summary. 1571 Summ = getPersistentSummary(NoRet, Dealloc); 1572 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1573 1574 // Create the "autorelease" selector. 1575 Summ = getPersistentSummary(NoRet, Autorelease); 1576 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1577 1578 // Specially handle NSAutoreleasePool. 1579 addInstMethSummary("NSAutoreleasePool", "init", 1580 getPersistentSummary(NoRet, NewAutoreleasePool)); 1581 1582 // For NSWindow, allocated objects are (initially) self-owned. 1583 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1584 // self-own themselves. However, they only do this once they are displayed. 1585 // Thus, we need to track an NSWindow's display status. 1586 // This is tracked in <rdar://problem/6062711>. 1587 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1588 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1589 StopTracking, 1590 StopTracking); 1591 1592 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1593 1594#if 0 1595 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1596 "styleMask", "backing", "defer", NULL); 1597 1598 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1599 "styleMask", "backing", "defer", "screen", NULL); 1600#endif 1601 1602 // For NSPanel (which subclasses NSWindow), allocated objects are not 1603 // self-owned. 1604 // FIXME: For now we don't track NSPanels. object for the same reason 1605 // as for NSWindow objects. 1606 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1607 1608#if 0 1609 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1610 "styleMask", "backing", "defer", NULL); 1611 1612 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1613 "styleMask", "backing", "defer", "screen", NULL); 1614#endif 1615 1616 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1617 // exit a method. 1618 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1619 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1620 1621 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1622 addInstMethSummary("QCRenderer", AllocSumm, 1623 "createSnapshotImageOfType", NULL); 1624 addInstMethSummary("QCView", AllocSumm, 1625 "createSnapshotImageOfType", NULL); 1626 1627 // Create summaries for CIContext, 'createCGImage' and 1628 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1629 // automatically garbage collected. 1630 addInstMethSummary("CIContext", CFAllocSumm, 1631 "createCGImage", "fromRect", NULL); 1632 addInstMethSummary("CIContext", CFAllocSumm, 1633 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1634 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1635 "info", NULL); 1636} 1637 1638//===----------------------------------------------------------------------===// 1639// AutoreleaseBindings - State used to track objects in autorelease pools. 1640//===----------------------------------------------------------------------===// 1641#define AUTORELEASE_POOL_MODELING (0) 1642// We do not currently have complete modeling of autorelease pools. 1643 1644#if AUTORELEASE_POOL_MODELING 1645 1646typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1647typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1648typedef llvm::ImmutableList<SymbolRef> ARStack; 1649 1650static int AutoRCIndex = 0; 1651static int AutoRBIndex = 0; 1652 1653namespace { class AutoreleasePoolContents {}; } 1654namespace { class AutoreleaseStack {}; } 1655 1656namespace clang { 1657namespace ento { 1658template<> struct ProgramStateTrait<AutoreleaseStack> 1659 : public ProgramStatePartialTrait<ARStack> { 1660 static inline void *GDMIndex() { return &AutoRBIndex; } 1661}; 1662 1663template<> struct ProgramStateTrait<AutoreleasePoolContents> 1664 : public ProgramStatePartialTrait<ARPoolContents> { 1665 static inline void *GDMIndex() { return &AutoRCIndex; } 1666}; 1667} // end GR namespace 1668} // end clang namespace 1669 1670static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1671 ARStack stack = state->get<AutoreleaseStack>(); 1672 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1673} 1674 1675static ProgramStateRef 1676SendAutorelease(ProgramStateRef state, 1677 ARCounts::Factory &F, 1678 SymbolRef sym) { 1679 SymbolRef pool = GetCurrentAutoreleasePool(state); 1680 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1681 ARCounts newCnts(0); 1682 1683 if (cnts) { 1684 const unsigned *cnt = (*cnts).lookup(sym); 1685 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1686 } 1687 else 1688 newCnts = F.add(F.getEmptyMap(), sym, 1); 1689 1690 return state->set<AutoreleasePoolContents>(pool, newCnts); 1691} 1692#endif 1693 1694//===----------------------------------------------------------------------===// 1695// Error reporting. 1696//===----------------------------------------------------------------------===// 1697namespace { 1698 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1699 SummaryLogTy; 1700 1701 //===-------------===// 1702 // Bug Descriptions. // 1703 //===-------------===// 1704 1705 class CFRefBug : public BugType { 1706 protected: 1707 CFRefBug(StringRef name) 1708 : BugType(name, categories::MemoryCoreFoundationObjectiveC) {} 1709 public: 1710 1711 // FIXME: Eventually remove. 1712 virtual const char *getDescription() const = 0; 1713 1714 virtual bool isLeak() const { return false; } 1715 }; 1716 1717 class UseAfterRelease : public CFRefBug { 1718 public: 1719 UseAfterRelease() : CFRefBug("Use-after-release") {} 1720 1721 const char *getDescription() const { 1722 return "Reference-counted object is used after it is released"; 1723 } 1724 }; 1725 1726 class BadRelease : public CFRefBug { 1727 public: 1728 BadRelease() : CFRefBug("Bad release") {} 1729 1730 const char *getDescription() const { 1731 return "Incorrect decrement of the reference count of an object that is " 1732 "not owned at this point by the caller"; 1733 } 1734 }; 1735 1736 class DeallocGC : public CFRefBug { 1737 public: 1738 DeallocGC() 1739 : CFRefBug("-dealloc called while using garbage collection") {} 1740 1741 const char *getDescription() const { 1742 return "-dealloc called while using garbage collection"; 1743 } 1744 }; 1745 1746 class DeallocNotOwned : public CFRefBug { 1747 public: 1748 DeallocNotOwned() 1749 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1750 1751 const char *getDescription() const { 1752 return "-dealloc sent to object that may be referenced elsewhere"; 1753 } 1754 }; 1755 1756 class OverAutorelease : public CFRefBug { 1757 public: 1758 OverAutorelease() 1759 : CFRefBug("Object sent -autorelease too many times") {} 1760 1761 const char *getDescription() const { 1762 return "Object sent -autorelease too many times"; 1763 } 1764 }; 1765 1766 class ReturnedNotOwnedForOwned : public CFRefBug { 1767 public: 1768 ReturnedNotOwnedForOwned() 1769 : CFRefBug("Method should return an owned object") {} 1770 1771 const char *getDescription() const { 1772 return "Object with a +0 retain count returned to caller where a +1 " 1773 "(owning) retain count is expected"; 1774 } 1775 }; 1776 1777 class Leak : public CFRefBug { 1778 public: 1779 Leak(StringRef name) 1780 : CFRefBug(name) { 1781 // Leaks should not be reported if they are post-dominated by a sink. 1782 setSuppressOnSink(true); 1783 } 1784 1785 const char *getDescription() const { return ""; } 1786 1787 bool isLeak() const { return true; } 1788 }; 1789 1790 //===---------===// 1791 // Bug Reports. // 1792 //===---------===// 1793 1794 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1795 protected: 1796 SymbolRef Sym; 1797 const SummaryLogTy &SummaryLog; 1798 bool GCEnabled; 1799 1800 public: 1801 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1802 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1803 1804 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1805 static int x = 0; 1806 ID.AddPointer(&x); 1807 ID.AddPointer(Sym); 1808 } 1809 1810 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1811 const ExplodedNode *PrevN, 1812 BugReporterContext &BRC, 1813 BugReport &BR); 1814 1815 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1816 const ExplodedNode *N, 1817 BugReport &BR); 1818 }; 1819 1820 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1821 public: 1822 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1823 const SummaryLogTy &log) 1824 : CFRefReportVisitor(sym, GCEnabled, log) {} 1825 1826 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1827 const ExplodedNode *N, 1828 BugReport &BR); 1829 1830 virtual BugReporterVisitor *clone() const { 1831 // The curiously-recurring template pattern only works for one level of 1832 // subclassing. Rather than make a new template base for 1833 // CFRefReportVisitor, we simply override clone() to do the right thing. 1834 // This could be trouble someday if BugReporterVisitorImpl is ever 1835 // used for something else besides a convenient implementation of clone(). 1836 return new CFRefLeakReportVisitor(*this); 1837 } 1838 }; 1839 1840 class CFRefReport : public BugReport { 1841 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1842 1843 public: 1844 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1845 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1846 bool registerVisitor = true) 1847 : BugReport(D, D.getDescription(), n) { 1848 if (registerVisitor) 1849 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1850 addGCModeDescription(LOpts, GCEnabled); 1851 } 1852 1853 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1854 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1855 StringRef endText) 1856 : BugReport(D, D.getDescription(), endText, n) { 1857 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1858 addGCModeDescription(LOpts, GCEnabled); 1859 } 1860 1861 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1862 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1863 if (!BugTy.isLeak()) 1864 return BugReport::getRanges(); 1865 else 1866 return std::make_pair(ranges_iterator(), ranges_iterator()); 1867 } 1868 }; 1869 1870 class CFRefLeakReport : public CFRefReport { 1871 const MemRegion* AllocBinding; 1872 1873 public: 1874 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1875 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1876 CheckerContext &Ctx); 1877 1878 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1879 assert(Location.isValid()); 1880 return Location; 1881 } 1882 }; 1883} // end anonymous namespace 1884 1885void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1886 bool GCEnabled) { 1887 const char *GCModeDescription = 0; 1888 1889 switch (LOpts.getGC()) { 1890 case LangOptions::GCOnly: 1891 assert(GCEnabled); 1892 GCModeDescription = "Code is compiled to only use garbage collection"; 1893 break; 1894 1895 case LangOptions::NonGC: 1896 assert(!GCEnabled); 1897 GCModeDescription = "Code is compiled to use reference counts"; 1898 break; 1899 1900 case LangOptions::HybridGC: 1901 if (GCEnabled) { 1902 GCModeDescription = "Code is compiled to use either garbage collection " 1903 "(GC) or reference counts (non-GC). The bug occurs " 1904 "with GC enabled"; 1905 break; 1906 } else { 1907 GCModeDescription = "Code is compiled to use either garbage collection " 1908 "(GC) or reference counts (non-GC). The bug occurs " 1909 "in non-GC mode"; 1910 break; 1911 } 1912 } 1913 1914 assert(GCModeDescription && "invalid/unknown GC mode"); 1915 addExtraText(GCModeDescription); 1916} 1917 1918// FIXME: This should be a method on SmallVector. 1919static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1920 ArgEffect X) { 1921 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1922 I!=E; ++I) 1923 if (*I == X) return true; 1924 1925 return false; 1926} 1927 1928static bool isNumericLiteralExpression(const Expr *E) { 1929 // FIXME: This set of cases was copied from SemaExprObjC. 1930 return isa<IntegerLiteral>(E) || 1931 isa<CharacterLiteral>(E) || 1932 isa<FloatingLiteral>(E) || 1933 isa<ObjCBoolLiteralExpr>(E) || 1934 isa<CXXBoolLiteralExpr>(E); 1935} 1936 1937PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1938 const ExplodedNode *PrevN, 1939 BugReporterContext &BRC, 1940 BugReport &BR) { 1941 // FIXME: We will eventually need to handle non-statement-based events 1942 // (__attribute__((cleanup))). 1943 if (!isa<StmtPoint>(N->getLocation())) 1944 return NULL; 1945 1946 // Check if the type state has changed. 1947 ProgramStateRef PrevSt = PrevN->getState(); 1948 ProgramStateRef CurrSt = N->getState(); 1949 const LocationContext *LCtx = N->getLocationContext(); 1950 1951 const RefVal* CurrT = getRefBinding(CurrSt, Sym); 1952 if (!CurrT) return NULL; 1953 1954 const RefVal &CurrV = *CurrT; 1955 const RefVal *PrevT = getRefBinding(PrevSt, Sym); 1956 1957 // Create a string buffer to constain all the useful things we want 1958 // to tell the user. 1959 std::string sbuf; 1960 llvm::raw_string_ostream os(sbuf); 1961 1962 // This is the allocation site since the previous node had no bindings 1963 // for this symbol. 1964 if (!PrevT) { 1965 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1966 1967 if (isa<ObjCArrayLiteral>(S)) { 1968 os << "NSArray literal is an object with a +0 retain count"; 1969 } 1970 else if (isa<ObjCDictionaryLiteral>(S)) { 1971 os << "NSDictionary literal is an object with a +0 retain count"; 1972 } 1973 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1974 if (isNumericLiteralExpression(BL->getSubExpr())) 1975 os << "NSNumber literal is an object with a +0 retain count"; 1976 else { 1977 const ObjCInterfaceDecl *BoxClass = 0; 1978 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1979 BoxClass = Method->getClassInterface(); 1980 1981 // We should always be able to find the boxing class interface, 1982 // but consider this future-proofing. 1983 if (BoxClass) 1984 os << *BoxClass << " b"; 1985 else 1986 os << "B"; 1987 1988 os << "oxed expression produces an object with a +0 retain count"; 1989 } 1990 } 1991 else { 1992 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1993 // Get the name of the callee (if it is available). 1994 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1995 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1996 os << "Call to function '" << *FD << '\''; 1997 else 1998 os << "function call"; 1999 } 2000 else { 2001 assert(isa<ObjCMessageExpr>(S)); 2002 CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager(); 2003 CallEventRef<ObjCMethodCall> Call 2004 = Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx); 2005 2006 switch (Call->getMessageKind()) { 2007 case OCM_Message: 2008 os << "Method"; 2009 break; 2010 case OCM_PropertyAccess: 2011 os << "Property"; 2012 break; 2013 case OCM_Subscript: 2014 os << "Subscript"; 2015 break; 2016 } 2017 } 2018 2019 if (CurrV.getObjKind() == RetEffect::CF) { 2020 os << " returns a Core Foundation object with a "; 2021 } 2022 else { 2023 assert (CurrV.getObjKind() == RetEffect::ObjC); 2024 os << " returns an Objective-C object with a "; 2025 } 2026 2027 if (CurrV.isOwned()) { 2028 os << "+1 retain count"; 2029 2030 if (GCEnabled) { 2031 assert(CurrV.getObjKind() == RetEffect::CF); 2032 os << ". " 2033 "Core Foundation objects are not automatically garbage collected."; 2034 } 2035 } 2036 else { 2037 assert (CurrV.isNotOwned()); 2038 os << "+0 retain count"; 2039 } 2040 } 2041 2042 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2043 N->getLocationContext()); 2044 return new PathDiagnosticEventPiece(Pos, os.str()); 2045 } 2046 2047 // Gather up the effects that were performed on the object at this 2048 // program point 2049 SmallVector<ArgEffect, 2> AEffects; 2050 2051 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 2052 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 2053 // We only have summaries attached to nodes after evaluating CallExpr and 2054 // ObjCMessageExprs. 2055 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2056 2057 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 2058 // Iterate through the parameter expressions and see if the symbol 2059 // was ever passed as an argument. 2060 unsigned i = 0; 2061 2062 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 2063 AI!=AE; ++AI, ++i) { 2064 2065 // Retrieve the value of the argument. Is it the symbol 2066 // we are interested in? 2067 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 2068 continue; 2069 2070 // We have an argument. Get the effect! 2071 AEffects.push_back(Summ->getArg(i)); 2072 } 2073 } 2074 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 2075 if (const Expr *receiver = ME->getInstanceReceiver()) 2076 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 2077 .getAsLocSymbol() == Sym) { 2078 // The symbol we are tracking is the receiver. 2079 AEffects.push_back(Summ->getReceiverEffect()); 2080 } 2081 } 2082 } 2083 2084 do { 2085 // Get the previous type state. 2086 RefVal PrevV = *PrevT; 2087 2088 // Specially handle -dealloc. 2089 if (!GCEnabled && contains(AEffects, Dealloc)) { 2090 // Determine if the object's reference count was pushed to zero. 2091 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2092 // We may not have transitioned to 'release' if we hit an error. 2093 // This case is handled elsewhere. 2094 if (CurrV.getKind() == RefVal::Released) { 2095 assert(CurrV.getCombinedCounts() == 0); 2096 os << "Object released by directly sending the '-dealloc' message"; 2097 break; 2098 } 2099 } 2100 2101 // Specially handle CFMakeCollectable and friends. 2102 if (contains(AEffects, MakeCollectable)) { 2103 // Get the name of the function. 2104 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2105 SVal X = 2106 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2107 const FunctionDecl *FD = X.getAsFunctionDecl(); 2108 2109 if (GCEnabled) { 2110 // Determine if the object's reference count was pushed to zero. 2111 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2112 2113 os << "In GC mode a call to '" << *FD 2114 << "' decrements an object's retain count and registers the " 2115 "object with the garbage collector. "; 2116 2117 if (CurrV.getKind() == RefVal::Released) { 2118 assert(CurrV.getCount() == 0); 2119 os << "Since it now has a 0 retain count the object can be " 2120 "automatically collected by the garbage collector."; 2121 } 2122 else 2123 os << "An object must have a 0 retain count to be garbage collected. " 2124 "After this call its retain count is +" << CurrV.getCount() 2125 << '.'; 2126 } 2127 else 2128 os << "When GC is not enabled a call to '" << *FD 2129 << "' has no effect on its argument."; 2130 2131 // Nothing more to say. 2132 break; 2133 } 2134 2135 // Determine if the typestate has changed. 2136 if (!(PrevV == CurrV)) 2137 switch (CurrV.getKind()) { 2138 case RefVal::Owned: 2139 case RefVal::NotOwned: 2140 2141 if (PrevV.getCount() == CurrV.getCount()) { 2142 // Did an autorelease message get sent? 2143 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2144 return 0; 2145 2146 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2147 os << "Object sent -autorelease message"; 2148 break; 2149 } 2150 2151 if (PrevV.getCount() > CurrV.getCount()) 2152 os << "Reference count decremented."; 2153 else 2154 os << "Reference count incremented."; 2155 2156 if (unsigned Count = CurrV.getCount()) 2157 os << " The object now has a +" << Count << " retain count."; 2158 2159 if (PrevV.getKind() == RefVal::Released) { 2160 assert(GCEnabled && CurrV.getCount() > 0); 2161 os << " The object is not eligible for garbage collection until " 2162 "the retain count reaches 0 again."; 2163 } 2164 2165 break; 2166 2167 case RefVal::Released: 2168 os << "Object released."; 2169 break; 2170 2171 case RefVal::ReturnedOwned: 2172 // Autoreleases can be applied after marking a node ReturnedOwned. 2173 if (CurrV.getAutoreleaseCount()) 2174 return NULL; 2175 2176 os << "Object returned to caller as an owning reference (single " 2177 "retain count transferred to caller)"; 2178 break; 2179 2180 case RefVal::ReturnedNotOwned: 2181 os << "Object returned to caller with a +0 retain count"; 2182 break; 2183 2184 default: 2185 return NULL; 2186 } 2187 2188 // Emit any remaining diagnostics for the argument effects (if any). 2189 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2190 E=AEffects.end(); I != E; ++I) { 2191 2192 // A bunch of things have alternate behavior under GC. 2193 if (GCEnabled) 2194 switch (*I) { 2195 default: break; 2196 case Autorelease: 2197 os << "In GC mode an 'autorelease' has no effect."; 2198 continue; 2199 case IncRefMsg: 2200 os << "In GC mode the 'retain' message has no effect."; 2201 continue; 2202 case DecRefMsg: 2203 os << "In GC mode the 'release' message has no effect."; 2204 continue; 2205 } 2206 } 2207 } while (0); 2208 2209 if (os.str().empty()) 2210 return 0; // We have nothing to say! 2211 2212 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2213 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2214 N->getLocationContext()); 2215 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2216 2217 // Add the range by scanning the children of the statement for any bindings 2218 // to Sym. 2219 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2220 I!=E; ++I) 2221 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2222 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2223 P->addRange(Exp->getSourceRange()); 2224 break; 2225 } 2226 2227 return P; 2228} 2229 2230// Find the first node in the current function context that referred to the 2231// tracked symbol and the memory location that value was stored to. Note, the 2232// value is only reported if the allocation occurred in the same function as 2233// the leak. 2234static std::pair<const ExplodedNode*,const MemRegion*> 2235GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2236 SymbolRef Sym) { 2237 const ExplodedNode *Last = N; 2238 const MemRegion* FirstBinding = 0; 2239 const LocationContext *LeakContext = N->getLocationContext(); 2240 2241 while (N) { 2242 ProgramStateRef St = N->getState(); 2243 2244 if (!getRefBinding(St, Sym)) 2245 break; 2246 2247 StoreManager::FindUniqueBinding FB(Sym); 2248 StateMgr.iterBindings(St, FB); 2249 if (FB) FirstBinding = FB.getRegion(); 2250 2251 // Allocation node, is the last node in the current context in which the 2252 // symbol was tracked. 2253 if (N->getLocationContext() == LeakContext) 2254 Last = N; 2255 2256 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2257 } 2258 2259 // If allocation happened in a function different from the leak node context, 2260 // do not report the binding. 2261 if (N->getLocationContext() != LeakContext) { 2262 FirstBinding = 0; 2263 } 2264 2265 return std::make_pair(Last, FirstBinding); 2266} 2267 2268PathDiagnosticPiece* 2269CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2270 const ExplodedNode *EndN, 2271 BugReport &BR) { 2272 BR.markInteresting(Sym); 2273 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2274} 2275 2276PathDiagnosticPiece* 2277CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2278 const ExplodedNode *EndN, 2279 BugReport &BR) { 2280 2281 // Tell the BugReporterContext to report cases when the tracked symbol is 2282 // assigned to different variables, etc. 2283 BR.markInteresting(Sym); 2284 2285 // We are reporting a leak. Walk up the graph to get to the first node where 2286 // the symbol appeared, and also get the first VarDecl that tracked object 2287 // is stored to. 2288 const ExplodedNode *AllocNode = 0; 2289 const MemRegion* FirstBinding = 0; 2290 2291 llvm::tie(AllocNode, FirstBinding) = 2292 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2293 2294 SourceManager& SM = BRC.getSourceManager(); 2295 2296 // Compute an actual location for the leak. Sometimes a leak doesn't 2297 // occur at an actual statement (e.g., transition between blocks; end 2298 // of function) so we need to walk the graph and compute a real location. 2299 const ExplodedNode *LeakN = EndN; 2300 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2301 2302 std::string sbuf; 2303 llvm::raw_string_ostream os(sbuf); 2304 2305 os << "Object leaked: "; 2306 2307 if (FirstBinding) { 2308 os << "object allocated and stored into '" 2309 << FirstBinding->getString() << '\''; 2310 } 2311 else 2312 os << "allocated object"; 2313 2314 // Get the retain count. 2315 const RefVal* RV = getRefBinding(EndN->getState(), Sym); 2316 2317 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2318 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2319 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2320 // to the caller for NS objects. 2321 const Decl *D = &EndN->getCodeDecl(); 2322 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2323 os << " is returned from a method whose name ('" 2324 << MD->getSelector().getAsString() 2325 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2326 " This violates the naming convention rules" 2327 " given in the Memory Management Guide for Cocoa"; 2328 } 2329 else { 2330 const FunctionDecl *FD = cast<FunctionDecl>(D); 2331 os << " is returned from a function whose name ('" 2332 << *FD 2333 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2334 " convention rules given in the Memory Management Guide for Core" 2335 " Foundation"; 2336 } 2337 } 2338 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2339 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2340 os << " and returned from method '" << MD.getSelector().getAsString() 2341 << "' is potentially leaked when using garbage collection. Callers " 2342 "of this method do not expect a returned object with a +1 retain " 2343 "count since they expect the object to be managed by the garbage " 2344 "collector"; 2345 } 2346 else 2347 os << " is not referenced later in this execution path and has a retain " 2348 "count of +" << RV->getCount(); 2349 2350 return new PathDiagnosticEventPiece(L, os.str()); 2351} 2352 2353CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2354 bool GCEnabled, const SummaryLogTy &Log, 2355 ExplodedNode *n, SymbolRef sym, 2356 CheckerContext &Ctx) 2357: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2358 2359 // Most bug reports are cached at the location where they occurred. 2360 // With leaks, we want to unique them by the location where they were 2361 // allocated, and only report a single path. To do this, we need to find 2362 // the allocation site of a piece of tracked memory, which we do via a 2363 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2364 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2365 // that all ancestor nodes that represent the allocation site have the 2366 // same SourceLocation. 2367 const ExplodedNode *AllocNode = 0; 2368 2369 const SourceManager& SMgr = Ctx.getSourceManager(); 2370 2371 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2372 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2373 2374 // Get the SourceLocation for the allocation site. 2375 // FIXME: This will crash the analyzer if an allocation comes from an 2376 // implicit call. (Currently there are no such allocations in Cocoa, though.) 2377 const Stmt *AllocStmt; 2378 ProgramPoint P = AllocNode->getLocation(); 2379 if (CallExitEnd *Exit = dyn_cast<CallExitEnd>(&P)) 2380 AllocStmt = Exit->getCalleeContext()->getCallSite(); 2381 else 2382 AllocStmt = cast<PostStmt>(P).getStmt(); 2383 assert(AllocStmt && "All allocations must come from explicit calls"); 2384 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2385 n->getLocationContext()); 2386 // Fill in the description of the bug. 2387 Description.clear(); 2388 llvm::raw_string_ostream os(Description); 2389 os << "Potential leak "; 2390 if (GCEnabled) 2391 os << "(when using garbage collection) "; 2392 os << "of an object"; 2393 2394 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2395 if (AllocBinding) 2396 os << " stored into '" << AllocBinding->getString() << '\''; 2397 2398 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2399} 2400 2401//===----------------------------------------------------------------------===// 2402// Main checker logic. 2403//===----------------------------------------------------------------------===// 2404 2405namespace { 2406class RetainCountChecker 2407 : public Checker< check::Bind, 2408 check::DeadSymbols, 2409 check::EndAnalysis, 2410 check::EndPath, 2411 check::PostStmt<BlockExpr>, 2412 check::PostStmt<CastExpr>, 2413 check::PostStmt<ObjCArrayLiteral>, 2414 check::PostStmt<ObjCDictionaryLiteral>, 2415 check::PostStmt<ObjCBoxedExpr>, 2416 check::PostCall, 2417 check::PreStmt<ReturnStmt>, 2418 check::RegionChanges, 2419 eval::Assume, 2420 eval::Call > { 2421 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2422 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2423 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2424 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2425 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2426 2427 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2428 2429 // This map is only used to ensure proper deletion of any allocated tags. 2430 mutable SymbolTagMap DeadSymbolTags; 2431 2432 mutable OwningPtr<RetainSummaryManager> Summaries; 2433 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2434 2435#if AUTORELEASE_POOL_MODELING 2436 mutable ARCounts::Factory ARCountFactory; 2437#endif 2438 2439 mutable SummaryLogTy SummaryLog; 2440 mutable bool ShouldResetSummaryLog; 2441 2442public: 2443 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2444 2445 virtual ~RetainCountChecker() { 2446 DeleteContainerSeconds(DeadSymbolTags); 2447 } 2448 2449 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2450 ExprEngine &Eng) const { 2451 // FIXME: This is a hack to make sure the summary log gets cleared between 2452 // analyses of different code bodies. 2453 // 2454 // Why is this necessary? Because a checker's lifetime is tied to a 2455 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2456 // Once in a blue moon, a new ExplodedNode will have the same address as an 2457 // old one with an associated summary, and the bug report visitor gets very 2458 // confused. (To make things worse, the summary lifetime is currently also 2459 // tied to a code body, so we get a crash instead of incorrect results.) 2460 // 2461 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2462 // changes, things will start going wrong again. Really the lifetime of this 2463 // log needs to be tied to either the specific nodes in it or the entire 2464 // ExplodedGraph, not to a specific part of the code being analyzed. 2465 // 2466 // (Also, having stateful local data means that the same checker can't be 2467 // used from multiple threads, but a lot of checkers have incorrect 2468 // assumptions about that anyway. So that wasn't a priority at the time of 2469 // this fix.) 2470 // 2471 // This happens at the end of analysis, but bug reports are emitted /after/ 2472 // this point. So we can't just clear the summary log now. Instead, we mark 2473 // that the next time we access the summary log, it should be cleared. 2474 2475 // If we never reset the summary log during /this/ code body analysis, 2476 // there were no new summaries. There might still have been summaries from 2477 // the /last/ analysis, so clear them out to make sure the bug report 2478 // visitors don't get confused. 2479 if (ShouldResetSummaryLog) 2480 SummaryLog.clear(); 2481 2482 ShouldResetSummaryLog = !SummaryLog.empty(); 2483 } 2484 2485 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2486 bool GCEnabled) const { 2487 if (GCEnabled) { 2488 if (!leakWithinFunctionGC) 2489 leakWithinFunctionGC.reset(new Leak("Leak of object when using " 2490 "garbage collection")); 2491 return leakWithinFunctionGC.get(); 2492 } else { 2493 if (!leakWithinFunction) { 2494 if (LOpts.getGC() == LangOptions::HybridGC) { 2495 leakWithinFunction.reset(new Leak("Leak of object when not using " 2496 "garbage collection (GC) in " 2497 "dual GC/non-GC code")); 2498 } else { 2499 leakWithinFunction.reset(new Leak("Leak")); 2500 } 2501 } 2502 return leakWithinFunction.get(); 2503 } 2504 } 2505 2506 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2507 if (GCEnabled) { 2508 if (!leakAtReturnGC) 2509 leakAtReturnGC.reset(new Leak("Leak of returned object when using " 2510 "garbage collection")); 2511 return leakAtReturnGC.get(); 2512 } else { 2513 if (!leakAtReturn) { 2514 if (LOpts.getGC() == LangOptions::HybridGC) { 2515 leakAtReturn.reset(new Leak("Leak of returned object when not using " 2516 "garbage collection (GC) in dual " 2517 "GC/non-GC code")); 2518 } else { 2519 leakAtReturn.reset(new Leak("Leak of returned object")); 2520 } 2521 } 2522 return leakAtReturn.get(); 2523 } 2524 } 2525 2526 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2527 bool GCEnabled) const { 2528 // FIXME: We don't support ARC being turned on and off during one analysis. 2529 // (nor, for that matter, do we support changing ASTContexts) 2530 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2531 if (GCEnabled) { 2532 if (!SummariesGC) 2533 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2534 else 2535 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2536 return *SummariesGC; 2537 } else { 2538 if (!Summaries) 2539 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2540 else 2541 assert(Summaries->isARCEnabled() == ARCEnabled); 2542 return *Summaries; 2543 } 2544 } 2545 2546 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2547 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2548 } 2549 2550 void printState(raw_ostream &Out, ProgramStateRef State, 2551 const char *NL, const char *Sep) const; 2552 2553 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2554 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2555 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2556 2557 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2558 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2559 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2560 2561 void checkPostCall(const CallEvent &Call, CheckerContext &C) const; 2562 2563 void checkSummary(const RetainSummary &Summ, const CallEvent &Call, 2564 CheckerContext &C) const; 2565 2566 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2567 2568 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2569 bool Assumption) const; 2570 2571 ProgramStateRef 2572 checkRegionChanges(ProgramStateRef state, 2573 const StoreManager::InvalidatedSymbols *invalidated, 2574 ArrayRef<const MemRegion *> ExplicitRegions, 2575 ArrayRef<const MemRegion *> Regions, 2576 const CallEvent *Call) const; 2577 2578 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2579 return true; 2580 } 2581 2582 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2583 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2584 ExplodedNode *Pred, RetEffect RE, RefVal X, 2585 SymbolRef Sym, ProgramStateRef state) const; 2586 2587 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2588 void checkEndPath(CheckerContext &C) const; 2589 2590 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2591 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2592 CheckerContext &C) const; 2593 2594 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2595 RefVal::Kind ErrorKind, SymbolRef Sym, 2596 CheckerContext &C) const; 2597 2598 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2599 2600 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2601 2602 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2603 SymbolRef sid, RefVal V, 2604 SmallVectorImpl<SymbolRef> &Leaked) const; 2605 2606 std::pair<ExplodedNode *, ProgramStateRef > 2607 handleAutoreleaseCounts(ProgramStateRef state, 2608 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2609 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2610 2611 ExplodedNode *processLeaks(ProgramStateRef state, 2612 SmallVectorImpl<SymbolRef> &Leaked, 2613 GenericNodeBuilderRefCount &Builder, 2614 CheckerContext &Ctx, 2615 ExplodedNode *Pred = 0) const; 2616}; 2617} // end anonymous namespace 2618 2619namespace { 2620class StopTrackingCallback : public SymbolVisitor { 2621 ProgramStateRef state; 2622public: 2623 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2624 ProgramStateRef getState() const { return state; } 2625 2626 bool VisitSymbol(SymbolRef sym) { 2627 state = state->remove<RefBindings>(sym); 2628 return true; 2629 } 2630}; 2631} // end anonymous namespace 2632 2633//===----------------------------------------------------------------------===// 2634// Handle statements that may have an effect on refcounts. 2635//===----------------------------------------------------------------------===// 2636 2637void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2638 CheckerContext &C) const { 2639 2640 // Scan the BlockDecRefExprs for any object the retain count checker 2641 // may be tracking. 2642 if (!BE->getBlockDecl()->hasCaptures()) 2643 return; 2644 2645 ProgramStateRef state = C.getState(); 2646 const BlockDataRegion *R = 2647 cast<BlockDataRegion>(state->getSVal(BE, 2648 C.getLocationContext()).getAsRegion()); 2649 2650 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2651 E = R->referenced_vars_end(); 2652 2653 if (I == E) 2654 return; 2655 2656 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2657 // via captured variables, even though captured variables result in a copy 2658 // and in implicit increment/decrement of a retain count. 2659 SmallVector<const MemRegion*, 10> Regions; 2660 const LocationContext *LC = C.getLocationContext(); 2661 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2662 2663 for ( ; I != E; ++I) { 2664 const VarRegion *VR = *I; 2665 if (VR->getSuperRegion() == R) { 2666 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2667 } 2668 Regions.push_back(VR); 2669 } 2670 2671 state = 2672 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2673 Regions.data() + Regions.size()).getState(); 2674 C.addTransition(state); 2675} 2676 2677void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2678 CheckerContext &C) const { 2679 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2680 if (!BE) 2681 return; 2682 2683 ArgEffect AE = IncRef; 2684 2685 switch (BE->getBridgeKind()) { 2686 case clang::OBC_Bridge: 2687 // Do nothing. 2688 return; 2689 case clang::OBC_BridgeRetained: 2690 AE = IncRef; 2691 break; 2692 case clang::OBC_BridgeTransfer: 2693 AE = DecRefBridgedTransfered; 2694 break; 2695 } 2696 2697 ProgramStateRef state = C.getState(); 2698 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2699 if (!Sym) 2700 return; 2701 const RefVal* T = getRefBinding(state, Sym); 2702 if (!T) 2703 return; 2704 2705 RefVal::Kind hasErr = (RefVal::Kind) 0; 2706 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2707 2708 if (hasErr) { 2709 // FIXME: If we get an error during a bridge cast, should we report it? 2710 // Should we assert that there is no error? 2711 return; 2712 } 2713 2714 C.addTransition(state); 2715} 2716 2717void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2718 const Expr *Ex) const { 2719 ProgramStateRef state = C.getState(); 2720 const ExplodedNode *pred = C.getPredecessor(); 2721 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2722 it != et ; ++it) { 2723 const Stmt *child = *it; 2724 SVal V = state->getSVal(child, pred->getLocationContext()); 2725 if (SymbolRef sym = V.getAsSymbol()) 2726 if (const RefVal* T = getRefBinding(state, sym)) { 2727 RefVal::Kind hasErr = (RefVal::Kind) 0; 2728 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2729 if (hasErr) { 2730 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2731 return; 2732 } 2733 } 2734 } 2735 2736 // Return the object as autoreleased. 2737 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2738 if (SymbolRef sym = 2739 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2740 QualType ResultTy = Ex->getType(); 2741 state = setRefBinding(state, sym, 2742 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2743 } 2744 2745 C.addTransition(state); 2746} 2747 2748void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2749 CheckerContext &C) const { 2750 // Apply the 'MayEscape' to all values. 2751 processObjCLiterals(C, AL); 2752} 2753 2754void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2755 CheckerContext &C) const { 2756 // Apply the 'MayEscape' to all keys and values. 2757 processObjCLiterals(C, DL); 2758} 2759 2760void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2761 CheckerContext &C) const { 2762 const ExplodedNode *Pred = C.getPredecessor(); 2763 const LocationContext *LCtx = Pred->getLocationContext(); 2764 ProgramStateRef State = Pred->getState(); 2765 2766 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2767 QualType ResultTy = Ex->getType(); 2768 State = setRefBinding(State, Sym, 2769 RefVal::makeNotOwned(RetEffect::ObjC, ResultTy)); 2770 } 2771 2772 C.addTransition(State); 2773} 2774 2775void RetainCountChecker::checkPostCall(const CallEvent &Call, 2776 CheckerContext &C) const { 2777 if (C.wasInlined) 2778 return; 2779 2780 RetainSummaryManager &Summaries = getSummaryManager(C); 2781 const RetainSummary *Summ = Summaries.getSummary(Call, C.getState()); 2782 checkSummary(*Summ, Call, C); 2783} 2784 2785/// GetReturnType - Used to get the return type of a message expression or 2786/// function call with the intention of affixing that type to a tracked symbol. 2787/// While the return type can be queried directly from RetEx, when 2788/// invoking class methods we augment to the return type to be that of 2789/// a pointer to the class (as opposed it just being id). 2790// FIXME: We may be able to do this with related result types instead. 2791// This function is probably overestimating. 2792static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2793 QualType RetTy = RetE->getType(); 2794 // If RetE is not a message expression just return its type. 2795 // If RetE is a message expression, return its types if it is something 2796 /// more specific than id. 2797 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2798 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2799 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2800 PT->isObjCClassType()) { 2801 // At this point we know the return type of the message expression is 2802 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2803 // is a call to a class method whose type we can resolve. In such 2804 // cases, promote the return type to XXX* (where XXX is the class). 2805 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2806 return !D ? RetTy : 2807 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2808 } 2809 2810 return RetTy; 2811} 2812 2813void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2814 const CallEvent &CallOrMsg, 2815 CheckerContext &C) const { 2816 ProgramStateRef state = C.getState(); 2817 2818 // Evaluate the effect of the arguments. 2819 RefVal::Kind hasErr = (RefVal::Kind) 0; 2820 SourceRange ErrorRange; 2821 SymbolRef ErrorSym = 0; 2822 2823 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2824 SVal V = CallOrMsg.getArgSVal(idx); 2825 2826 if (SymbolRef Sym = V.getAsLocSymbol()) { 2827 if (const RefVal *T = getRefBinding(state, Sym)) { 2828 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2829 if (hasErr) { 2830 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2831 ErrorSym = Sym; 2832 break; 2833 } 2834 } 2835 } 2836 } 2837 2838 // Evaluate the effect on the message receiver. 2839 bool ReceiverIsTracked = false; 2840 if (!hasErr) { 2841 const ObjCMethodCall *MsgInvocation = dyn_cast<ObjCMethodCall>(&CallOrMsg); 2842 if (MsgInvocation) { 2843 if (SymbolRef Sym = MsgInvocation->getReceiverSVal().getAsLocSymbol()) { 2844 if (const RefVal *T = getRefBinding(state, Sym)) { 2845 ReceiverIsTracked = true; 2846 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2847 hasErr, C); 2848 if (hasErr) { 2849 ErrorRange = MsgInvocation->getOriginExpr()->getReceiverRange(); 2850 ErrorSym = Sym; 2851 } 2852 } 2853 } 2854 } 2855 } 2856 2857 // Process any errors. 2858 if (hasErr) { 2859 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2860 return; 2861 } 2862 2863 // Consult the summary for the return value. 2864 RetEffect RE = Summ.getRetEffect(); 2865 2866 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2867 if (ReceiverIsTracked) 2868 RE = getSummaryManager(C).getObjAllocRetEffect(); 2869 else 2870 RE = RetEffect::MakeNoRet(); 2871 } 2872 2873 switch (RE.getKind()) { 2874 default: 2875 llvm_unreachable("Unhandled RetEffect."); 2876 2877 case RetEffect::NoRet: 2878 // No work necessary. 2879 break; 2880 2881 case RetEffect::OwnedAllocatedSymbol: 2882 case RetEffect::OwnedSymbol: { 2883 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2884 C.getLocationContext()).getAsSymbol(); 2885 if (!Sym) 2886 break; 2887 2888 // Use the result type from the CallEvent as it automatically adjusts 2889 // for methods/functions that return references. 2890 QualType ResultTy = CallOrMsg.getResultType(); 2891 state = setRefBinding(state, Sym, RefVal::makeOwned(RE.getObjKind(), 2892 ResultTy)); 2893 2894 // FIXME: Add a flag to the checker where allocations are assumed to 2895 // *not* fail. (The code below is out-of-date, though.) 2896#if 0 2897 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2898 bool isFeasible; 2899 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2900 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2901 } 2902#endif 2903 2904 break; 2905 } 2906 2907 case RetEffect::GCNotOwnedSymbol: 2908 case RetEffect::ARCNotOwnedSymbol: 2909 case RetEffect::NotOwnedSymbol: { 2910 const Expr *Ex = CallOrMsg.getOriginExpr(); 2911 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2912 if (!Sym) 2913 break; 2914 2915 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2916 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2917 state = setRefBinding(state, Sym, RefVal::makeNotOwned(RE.getObjKind(), 2918 ResultTy)); 2919 break; 2920 } 2921 } 2922 2923 // This check is actually necessary; otherwise the statement builder thinks 2924 // we've hit a previously-found path. 2925 // Normally addTransition takes care of this, but we want the node pointer. 2926 ExplodedNode *NewNode; 2927 if (state == C.getState()) { 2928 NewNode = C.getPredecessor(); 2929 } else { 2930 NewNode = C.addTransition(state); 2931 } 2932 2933 // Annotate the node with summary we used. 2934 if (NewNode) { 2935 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2936 if (ShouldResetSummaryLog) { 2937 SummaryLog.clear(); 2938 ShouldResetSummaryLog = false; 2939 } 2940 SummaryLog[NewNode] = &Summ; 2941 } 2942} 2943 2944 2945ProgramStateRef 2946RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2947 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2948 CheckerContext &C) const { 2949 // In GC mode [... release] and [... retain] do nothing. 2950 // In ARC mode they shouldn't exist at all, but we just ignore them. 2951 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2952 if (!IgnoreRetainMsg) 2953 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 2954 2955 switch (E) { 2956 default: 2957 break; 2958 case IncRefMsg: 2959 E = IgnoreRetainMsg ? DoNothing : IncRef; 2960 break; 2961 case DecRefMsg: 2962 E = IgnoreRetainMsg ? DoNothing : DecRef; 2963 break; 2964 case DecRefMsgAndStopTracking: 2965 E = IgnoreRetainMsg ? StopTracking : DecRefAndStopTracking; 2966 break; 2967 case MakeCollectable: 2968 E = C.isObjCGCEnabled() ? DecRef : DoNothing; 2969 break; 2970 case NewAutoreleasePool: 2971 E = C.isObjCGCEnabled() ? DoNothing : NewAutoreleasePool; 2972 break; 2973 } 2974 2975 // Handle all use-after-releases. 2976 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2977 V = V ^ RefVal::ErrorUseAfterRelease; 2978 hasErr = V.getKind(); 2979 return setRefBinding(state, sym, V); 2980 } 2981 2982 switch (E) { 2983 case DecRefMsg: 2984 case IncRefMsg: 2985 case MakeCollectable: 2986 case DecRefMsgAndStopTracking: 2987 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2988 2989 case Dealloc: 2990 // Any use of -dealloc in GC is *bad*. 2991 if (C.isObjCGCEnabled()) { 2992 V = V ^ RefVal::ErrorDeallocGC; 2993 hasErr = V.getKind(); 2994 break; 2995 } 2996 2997 switch (V.getKind()) { 2998 default: 2999 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 3000 case RefVal::Owned: 3001 // The object immediately transitions to the released state. 3002 V = V ^ RefVal::Released; 3003 V.clearCounts(); 3004 return setRefBinding(state, sym, V); 3005 case RefVal::NotOwned: 3006 V = V ^ RefVal::ErrorDeallocNotOwned; 3007 hasErr = V.getKind(); 3008 break; 3009 } 3010 break; 3011 3012 case NewAutoreleasePool: 3013 assert(!C.isObjCGCEnabled()); 3014#if AUTORELEASE_POOL_MODELING 3015 state = state->add<AutoreleaseStack>(sym); 3016#endif 3017 return state; 3018 3019 case MayEscape: 3020 if (V.getKind() == RefVal::Owned) { 3021 V = V ^ RefVal::NotOwned; 3022 break; 3023 } 3024 3025 // Fall-through. 3026 3027 case DoNothing: 3028 return state; 3029 3030 case Autorelease: 3031 if (C.isObjCGCEnabled()) 3032 return state; 3033 3034 // Update the autorelease counts. 3035 // TODO: AutoreleasePoolContents are not currently used. We will need to 3036 // call SendAutorelease after it's wired up. 3037#if AUTORELEASE_POOL_MODELING 3038 state = SendAutorelease(state, ARCountFactory, sym); 3039#endif 3040 V = V.autorelease(); 3041 break; 3042 3043 case StopTracking: 3044 return removeRefBinding(state, sym); 3045 3046 case IncRef: 3047 switch (V.getKind()) { 3048 default: 3049 llvm_unreachable("Invalid RefVal state for a retain."); 3050 case RefVal::Owned: 3051 case RefVal::NotOwned: 3052 V = V + 1; 3053 break; 3054 case RefVal::Released: 3055 // Non-GC cases are handled above. 3056 assert(C.isObjCGCEnabled()); 3057 V = (V ^ RefVal::Owned) + 1; 3058 break; 3059 } 3060 break; 3061 3062 case DecRef: 3063 case DecRefBridgedTransfered: 3064 case DecRefAndStopTracking: 3065 switch (V.getKind()) { 3066 default: 3067 // case 'RefVal::Released' handled above. 3068 llvm_unreachable("Invalid RefVal state for a release."); 3069 3070 case RefVal::Owned: 3071 assert(V.getCount() > 0); 3072 if (V.getCount() == 1) 3073 V = V ^ (E == DecRefBridgedTransfered ? 3074 RefVal::NotOwned : RefVal::Released); 3075 else if (E == DecRefAndStopTracking) 3076 return removeRefBinding(state, sym); 3077 3078 V = V - 1; 3079 break; 3080 3081 case RefVal::NotOwned: 3082 if (V.getCount() > 0) { 3083 if (E == DecRefAndStopTracking) 3084 return removeRefBinding(state, sym); 3085 V = V - 1; 3086 } else { 3087 V = V ^ RefVal::ErrorReleaseNotOwned; 3088 hasErr = V.getKind(); 3089 } 3090 break; 3091 3092 case RefVal::Released: 3093 // Non-GC cases are handled above. 3094 assert(C.isObjCGCEnabled()); 3095 V = V ^ RefVal::ErrorUseAfterRelease; 3096 hasErr = V.getKind(); 3097 break; 3098 } 3099 break; 3100 } 3101 return setRefBinding(state, sym, V); 3102} 3103 3104void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3105 SourceRange ErrorRange, 3106 RefVal::Kind ErrorKind, 3107 SymbolRef Sym, 3108 CheckerContext &C) const { 3109 ExplodedNode *N = C.generateSink(St); 3110 if (!N) 3111 return; 3112 3113 CFRefBug *BT; 3114 switch (ErrorKind) { 3115 default: 3116 llvm_unreachable("Unhandled error."); 3117 case RefVal::ErrorUseAfterRelease: 3118 if (!useAfterRelease) 3119 useAfterRelease.reset(new UseAfterRelease()); 3120 BT = &*useAfterRelease; 3121 break; 3122 case RefVal::ErrorReleaseNotOwned: 3123 if (!releaseNotOwned) 3124 releaseNotOwned.reset(new BadRelease()); 3125 BT = &*releaseNotOwned; 3126 break; 3127 case RefVal::ErrorDeallocGC: 3128 if (!deallocGC) 3129 deallocGC.reset(new DeallocGC()); 3130 BT = &*deallocGC; 3131 break; 3132 case RefVal::ErrorDeallocNotOwned: 3133 if (!deallocNotOwned) 3134 deallocNotOwned.reset(new DeallocNotOwned()); 3135 BT = &*deallocNotOwned; 3136 break; 3137 } 3138 3139 assert(BT); 3140 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3141 C.isObjCGCEnabled(), SummaryLog, 3142 N, Sym); 3143 report->addRange(ErrorRange); 3144 C.EmitReport(report); 3145} 3146 3147//===----------------------------------------------------------------------===// 3148// Handle the return values of retain-count-related functions. 3149//===----------------------------------------------------------------------===// 3150 3151bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3152 // Get the callee. We're only interested in simple C functions. 3153 ProgramStateRef state = C.getState(); 3154 const FunctionDecl *FD = C.getCalleeDecl(CE); 3155 if (!FD) 3156 return false; 3157 3158 IdentifierInfo *II = FD->getIdentifier(); 3159 if (!II) 3160 return false; 3161 3162 // For now, we're only handling the functions that return aliases of their 3163 // arguments: CFRetain and CFMakeCollectable (and their families). 3164 // Eventually we should add other functions we can model entirely, 3165 // such as CFRelease, which don't invalidate their arguments or globals. 3166 if (CE->getNumArgs() != 1) 3167 return false; 3168 3169 // Get the name of the function. 3170 StringRef FName = II->getName(); 3171 FName = FName.substr(FName.find_first_not_of('_')); 3172 3173 // See if it's one of the specific functions we know how to eval. 3174 bool canEval = false; 3175 3176 QualType ResultTy = CE->getCallReturnType(); 3177 if (ResultTy->isObjCIdType()) { 3178 // Handle: id NSMakeCollectable(CFTypeRef) 3179 canEval = II->isStr("NSMakeCollectable"); 3180 } else if (ResultTy->isPointerType()) { 3181 // Handle: (CF|CG)Retain 3182 // CFMakeCollectable 3183 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3184 if (cocoa::isRefType(ResultTy, "CF", FName) || 3185 cocoa::isRefType(ResultTy, "CG", FName)) { 3186 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3187 } 3188 } 3189 3190 if (!canEval) 3191 return false; 3192 3193 // Bind the return value. 3194 const LocationContext *LCtx = C.getLocationContext(); 3195 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3196 if (RetVal.isUnknown()) { 3197 // If the receiver is unknown, conjure a return value. 3198 SValBuilder &SVB = C.getSValBuilder(); 3199 unsigned Count = C.getCurrentBlockCount(); 3200 RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count); 3201 } 3202 state = state->BindExpr(CE, LCtx, RetVal, false); 3203 3204 // FIXME: This should not be necessary, but otherwise the argument seems to be 3205 // considered alive during the next statement. 3206 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3207 // Save the refcount status of the argument. 3208 SymbolRef Sym = RetVal.getAsLocSymbol(); 3209 const RefVal *Binding = 0; 3210 if (Sym) 3211 Binding = getRefBinding(state, Sym); 3212 3213 // Invalidate the argument region. 3214 unsigned Count = C.getCurrentBlockCount(); 3215 state = state->invalidateRegions(ArgRegion, CE, Count, LCtx); 3216 3217 // Restore the refcount status of the argument. 3218 if (Binding) 3219 state = setRefBinding(state, Sym, *Binding); 3220 } 3221 3222 C.addTransition(state); 3223 return true; 3224} 3225 3226//===----------------------------------------------------------------------===// 3227// Handle return statements. 3228//===----------------------------------------------------------------------===// 3229 3230// Return true if the current LocationContext has no caller context. 3231static bool inTopFrame(CheckerContext &C) { 3232 const LocationContext *LC = C.getLocationContext(); 3233 return LC->getParent() == 0; 3234} 3235 3236void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3237 CheckerContext &C) const { 3238 3239 // Only adjust the reference count if this is the top-level call frame, 3240 // and not the result of inlining. In the future, we should do 3241 // better checking even for inlined calls, and see if they match 3242 // with their expected semantics (e.g., the method should return a retained 3243 // object, etc.). 3244 if (!inTopFrame(C)) 3245 return; 3246 3247 const Expr *RetE = S->getRetValue(); 3248 if (!RetE) 3249 return; 3250 3251 ProgramStateRef state = C.getState(); 3252 SymbolRef Sym = 3253 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3254 if (!Sym) 3255 return; 3256 3257 // Get the reference count binding (if any). 3258 const RefVal *T = getRefBinding(state, Sym); 3259 if (!T) 3260 return; 3261 3262 // Change the reference count. 3263 RefVal X = *T; 3264 3265 switch (X.getKind()) { 3266 case RefVal::Owned: { 3267 unsigned cnt = X.getCount(); 3268 assert(cnt > 0); 3269 X.setCount(cnt - 1); 3270 X = X ^ RefVal::ReturnedOwned; 3271 break; 3272 } 3273 3274 case RefVal::NotOwned: { 3275 unsigned cnt = X.getCount(); 3276 if (cnt) { 3277 X.setCount(cnt - 1); 3278 X = X ^ RefVal::ReturnedOwned; 3279 } 3280 else { 3281 X = X ^ RefVal::ReturnedNotOwned; 3282 } 3283 break; 3284 } 3285 3286 default: 3287 return; 3288 } 3289 3290 // Update the binding. 3291 state = setRefBinding(state, Sym, X); 3292 ExplodedNode *Pred = C.addTransition(state); 3293 3294 // At this point we have updated the state properly. 3295 // Everything after this is merely checking to see if the return value has 3296 // been over- or under-retained. 3297 3298 // Did we cache out? 3299 if (!Pred) 3300 return; 3301 3302 // Update the autorelease counts. 3303 static SimpleProgramPointTag 3304 AutoreleaseTag("RetainCountChecker : Autorelease"); 3305 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3306 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3307 3308 // Did we cache out? 3309 if (!Pred) 3310 return; 3311 3312 // Get the updated binding. 3313 T = getRefBinding(state, Sym); 3314 assert(T); 3315 X = *T; 3316 3317 // Consult the summary of the enclosing method. 3318 RetainSummaryManager &Summaries = getSummaryManager(C); 3319 const Decl *CD = &Pred->getCodeDecl(); 3320 RetEffect RE = RetEffect::MakeNoRet(); 3321 3322 // FIXME: What is the convention for blocks? Is there one? 3323 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3324 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3325 RE = Summ->getRetEffect(); 3326 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3327 if (!isa<CXXMethodDecl>(FD)) { 3328 const RetainSummary *Summ = Summaries.getFunctionSummary(FD); 3329 RE = Summ->getRetEffect(); 3330 } 3331 } 3332 3333 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3334} 3335 3336void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3337 CheckerContext &C, 3338 ExplodedNode *Pred, 3339 RetEffect RE, RefVal X, 3340 SymbolRef Sym, 3341 ProgramStateRef state) const { 3342 // Any leaks or other errors? 3343 if (X.isReturnedOwned() && X.getCount() == 0) { 3344 if (RE.getKind() != RetEffect::NoRet) { 3345 bool hasError = false; 3346 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3347 // Things are more complicated with garbage collection. If the 3348 // returned object is suppose to be an Objective-C object, we have 3349 // a leak (as the caller expects a GC'ed object) because no 3350 // method should return ownership unless it returns a CF object. 3351 hasError = true; 3352 X = X ^ RefVal::ErrorGCLeakReturned; 3353 } 3354 else if (!RE.isOwned()) { 3355 // Either we are using GC and the returned object is a CF type 3356 // or we aren't using GC. In either case, we expect that the 3357 // enclosing method is expected to return ownership. 3358 hasError = true; 3359 X = X ^ RefVal::ErrorLeakReturned; 3360 } 3361 3362 if (hasError) { 3363 // Generate an error node. 3364 state = setRefBinding(state, Sym, X); 3365 3366 static SimpleProgramPointTag 3367 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3368 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3369 if (N) { 3370 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3371 bool GCEnabled = C.isObjCGCEnabled(); 3372 CFRefReport *report = 3373 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3374 LOpts, GCEnabled, SummaryLog, 3375 N, Sym, C); 3376 C.EmitReport(report); 3377 } 3378 } 3379 } 3380 } else if (X.isReturnedNotOwned()) { 3381 if (RE.isOwned()) { 3382 // Trying to return a not owned object to a caller expecting an 3383 // owned object. 3384 state = setRefBinding(state, Sym, X ^ RefVal::ErrorReturnedNotOwned); 3385 3386 static SimpleProgramPointTag 3387 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3388 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3389 if (N) { 3390 if (!returnNotOwnedForOwned) 3391 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3392 3393 CFRefReport *report = 3394 new CFRefReport(*returnNotOwnedForOwned, 3395 C.getASTContext().getLangOpts(), 3396 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3397 C.EmitReport(report); 3398 } 3399 } 3400 } 3401} 3402 3403//===----------------------------------------------------------------------===// 3404// Check various ways a symbol can be invalidated. 3405//===----------------------------------------------------------------------===// 3406 3407void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3408 CheckerContext &C) const { 3409 // Are we storing to something that causes the value to "escape"? 3410 bool escapes = true; 3411 3412 // A value escapes in three possible cases (this may change): 3413 // 3414 // (1) we are binding to something that is not a memory region. 3415 // (2) we are binding to a memregion that does not have stack storage 3416 // (3) we are binding to a memregion with stack storage that the store 3417 // does not understand. 3418 ProgramStateRef state = C.getState(); 3419 3420 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3421 escapes = !regionLoc->getRegion()->hasStackStorage(); 3422 3423 if (!escapes) { 3424 // To test (3), generate a new state with the binding added. If it is 3425 // the same state, then it escapes (since the store cannot represent 3426 // the binding). 3427 // Do this only if we know that the store is not supposed to generate the 3428 // same state. 3429 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3430 if (StoredVal != val) 3431 escapes = (state == (state->bindLoc(*regionLoc, val))); 3432 } 3433 if (!escapes) { 3434 // Case 4: We do not currently model what happens when a symbol is 3435 // assigned to a struct field, so be conservative here and let the symbol 3436 // go. TODO: This could definitely be improved upon. 3437 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3438 } 3439 } 3440 3441 // If our store can represent the binding and we aren't storing to something 3442 // that doesn't have local storage then just return and have the simulation 3443 // state continue as is. 3444 if (!escapes) 3445 return; 3446 3447 // Otherwise, find all symbols referenced by 'val' that we are tracking 3448 // and stop tracking them. 3449 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3450 C.addTransition(state); 3451} 3452 3453ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3454 SVal Cond, 3455 bool Assumption) const { 3456 3457 // FIXME: We may add to the interface of evalAssume the list of symbols 3458 // whose assumptions have changed. For now we just iterate through the 3459 // bindings and check if any of the tracked symbols are NULL. This isn't 3460 // too bad since the number of symbols we will track in practice are 3461 // probably small and evalAssume is only called at branches and a few 3462 // other places. 3463 RefBindings B = state->get<RefBindings>(); 3464 3465 if (B.isEmpty()) 3466 return state; 3467 3468 bool changed = false; 3469 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3470 3471 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3472 // Check if the symbol is null (or equal to any constant). 3473 // If this is the case, stop tracking the symbol. 3474 if (state->getSymVal(I.getKey())) { 3475 changed = true; 3476 B = RefBFactory.remove(B, I.getKey()); 3477 } 3478 } 3479 3480 if (changed) 3481 state = state->set<RefBindings>(B); 3482 3483 return state; 3484} 3485 3486ProgramStateRef 3487RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3488 const StoreManager::InvalidatedSymbols *invalidated, 3489 ArrayRef<const MemRegion *> ExplicitRegions, 3490 ArrayRef<const MemRegion *> Regions, 3491 const CallEvent *Call) const { 3492 if (!invalidated) 3493 return state; 3494 3495 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3496 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3497 E = ExplicitRegions.end(); I != E; ++I) { 3498 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3499 WhitelistedSymbols.insert(SR->getSymbol()); 3500 } 3501 3502 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3503 E = invalidated->end(); I!=E; ++I) { 3504 SymbolRef sym = *I; 3505 if (WhitelistedSymbols.count(sym)) 3506 continue; 3507 // Remove any existing reference-count binding. 3508 state = removeRefBinding(state, sym); 3509 } 3510 return state; 3511} 3512 3513//===----------------------------------------------------------------------===// 3514// Handle dead symbols and end-of-path. 3515//===----------------------------------------------------------------------===// 3516 3517std::pair<ExplodedNode *, ProgramStateRef > 3518RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3519 GenericNodeBuilderRefCount Bd, 3520 ExplodedNode *Pred, 3521 CheckerContext &Ctx, 3522 SymbolRef Sym, RefVal V) const { 3523 unsigned ACnt = V.getAutoreleaseCount(); 3524 3525 // No autorelease counts? Nothing to be done. 3526 if (!ACnt) 3527 return std::make_pair(Pred, state); 3528 3529 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3530 unsigned Cnt = V.getCount(); 3531 3532 // FIXME: Handle sending 'autorelease' to already released object. 3533 3534 if (V.getKind() == RefVal::ReturnedOwned) 3535 ++Cnt; 3536 3537 if (ACnt <= Cnt) { 3538 if (ACnt == Cnt) { 3539 V.clearCounts(); 3540 if (V.getKind() == RefVal::ReturnedOwned) 3541 V = V ^ RefVal::ReturnedNotOwned; 3542 else 3543 V = V ^ RefVal::NotOwned; 3544 } else { 3545 V.setCount(Cnt - ACnt); 3546 V.setAutoreleaseCount(0); 3547 } 3548 state = setRefBinding(state, Sym, V); 3549 ExplodedNode *N = Bd.MakeNode(state, Pred); 3550 if (N == 0) 3551 state = 0; 3552 return std::make_pair(N, state); 3553 } 3554 3555 // Woah! More autorelease counts then retain counts left. 3556 // Emit hard error. 3557 V = V ^ RefVal::ErrorOverAutorelease; 3558 state = setRefBinding(state, Sym, V); 3559 3560 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3561 SmallString<128> sbuf; 3562 llvm::raw_svector_ostream os(sbuf); 3563 os << "Object over-autoreleased: object was sent -autorelease "; 3564 if (V.getAutoreleaseCount() > 1) 3565 os << V.getAutoreleaseCount() << " times "; 3566 os << "but the object has a +" << V.getCount() << " retain count"; 3567 3568 if (!overAutorelease) 3569 overAutorelease.reset(new OverAutorelease()); 3570 3571 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3572 CFRefReport *report = 3573 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3574 SummaryLog, N, Sym, os.str()); 3575 Ctx.EmitReport(report); 3576 } 3577 3578 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3579} 3580 3581ProgramStateRef 3582RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3583 SymbolRef sid, RefVal V, 3584 SmallVectorImpl<SymbolRef> &Leaked) const { 3585 bool hasLeak = false; 3586 if (V.isOwned()) 3587 hasLeak = true; 3588 else if (V.isNotOwned() || V.isReturnedOwned()) 3589 hasLeak = (V.getCount() > 0); 3590 3591 if (!hasLeak) 3592 return removeRefBinding(state, sid); 3593 3594 Leaked.push_back(sid); 3595 return setRefBinding(state, sid, V ^ RefVal::ErrorLeak); 3596} 3597 3598ExplodedNode * 3599RetainCountChecker::processLeaks(ProgramStateRef state, 3600 SmallVectorImpl<SymbolRef> &Leaked, 3601 GenericNodeBuilderRefCount &Builder, 3602 CheckerContext &Ctx, 3603 ExplodedNode *Pred) const { 3604 if (Leaked.empty()) 3605 return Pred; 3606 3607 // Generate an intermediate node representing the leak point. 3608 ExplodedNode *N = Builder.MakeNode(state, Pred); 3609 3610 if (N) { 3611 for (SmallVectorImpl<SymbolRef>::iterator 3612 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3613 3614 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3615 bool GCEnabled = Ctx.isObjCGCEnabled(); 3616 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3617 : getLeakAtReturnBug(LOpts, GCEnabled); 3618 assert(BT && "BugType not initialized."); 3619 3620 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3621 SummaryLog, N, *I, Ctx); 3622 Ctx.EmitReport(report); 3623 } 3624 } 3625 3626 return N; 3627} 3628 3629void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3630 ProgramStateRef state = Ctx.getState(); 3631 GenericNodeBuilderRefCount Bd(Ctx); 3632 RefBindings B = state->get<RefBindings>(); 3633 ExplodedNode *Pred = Ctx.getPredecessor(); 3634 3635 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3636 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3637 I->first, I->second); 3638 if (!state) 3639 return; 3640 } 3641 3642 // If the current LocationContext has a parent, don't check for leaks. 3643 // We will do that later. 3644 // FIXME: we should instead check for imbalances of the retain/releases, 3645 // and suggest annotations. 3646 if (Ctx.getLocationContext()->getParent()) 3647 return; 3648 3649 B = state->get<RefBindings>(); 3650 SmallVector<SymbolRef, 10> Leaked; 3651 3652 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3653 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3654 3655 processLeaks(state, Leaked, Bd, Ctx, Pred); 3656} 3657 3658const ProgramPointTag * 3659RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3660 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3661 if (!tag) { 3662 SmallString<64> buf; 3663 llvm::raw_svector_ostream out(buf); 3664 out << "RetainCountChecker : Dead Symbol : "; 3665 sym->dumpToStream(out); 3666 tag = new SimpleProgramPointTag(out.str()); 3667 } 3668 return tag; 3669} 3670 3671void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3672 CheckerContext &C) const { 3673 ExplodedNode *Pred = C.getPredecessor(); 3674 3675 ProgramStateRef state = C.getState(); 3676 RefBindings B = state->get<RefBindings>(); 3677 3678 // Update counts from autorelease pools 3679 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3680 E = SymReaper.dead_end(); I != E; ++I) { 3681 SymbolRef Sym = *I; 3682 if (const RefVal *T = B.lookup(Sym)){ 3683 // Use the symbol as the tag. 3684 // FIXME: This might not be as unique as we would like. 3685 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3686 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3687 Sym, *T); 3688 if (!state) 3689 return; 3690 } 3691 } 3692 3693 B = state->get<RefBindings>(); 3694 SmallVector<SymbolRef, 10> Leaked; 3695 3696 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3697 E = SymReaper.dead_end(); I != E; ++I) { 3698 if (const RefVal *T = B.lookup(*I)) 3699 state = handleSymbolDeath(state, *I, *T, Leaked); 3700 } 3701 3702 { 3703 GenericNodeBuilderRefCount Bd(C, this); 3704 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3705 } 3706 3707 // Did we cache out? 3708 if (!Pred) 3709 return; 3710 3711 // Now generate a new node that nukes the old bindings. 3712 RefBindings::Factory &F = state->get_context<RefBindings>(); 3713 3714 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3715 E = SymReaper.dead_end(); I != E; ++I) 3716 B = F.remove(B, *I); 3717 3718 state = state->set<RefBindings>(B); 3719 C.addTransition(state, Pred); 3720} 3721 3722//===----------------------------------------------------------------------===// 3723// Debug printing of refcount bindings and autorelease pools. 3724//===----------------------------------------------------------------------===// 3725 3726#if AUTORELEASE_POOL_MODELING 3727static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3728 ProgramStateRef State) { 3729 Out << ' '; 3730 if (Sym) 3731 Sym->dumpToStream(Out); 3732 else 3733 Out << "<pool>"; 3734 Out << ":{"; 3735 3736 // Get the contents of the pool. 3737 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3738 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3739 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3740 Out << '}'; 3741} 3742 3743static bool UsesAutorelease(ProgramStateRef state) { 3744 // A state uses autorelease if it allocated an autorelease pool or if it has 3745 // objects in the caller's autorelease pool. 3746 return !state->get<AutoreleaseStack>().isEmpty() || 3747 state->get<AutoreleasePoolContents>(SymbolRef()); 3748} 3749#endif 3750 3751void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3752 const char *NL, const char *Sep) const { 3753 3754 RefBindings B = State->get<RefBindings>(); 3755 3756 if (!B.isEmpty()) 3757 Out << Sep << NL; 3758 3759 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3760 Out << I->first << " : "; 3761 I->second.print(Out); 3762 Out << NL; 3763 } 3764 3765#if AUTORELEASE_POOL_MODELING 3766 // Print the autorelease stack. 3767 if (UsesAutorelease(State)) { 3768 Out << Sep << NL << "AR pool stack:"; 3769 ARStack Stack = State->get<AutoreleaseStack>(); 3770 3771 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3772 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3773 PrintPool(Out, *I, State); 3774 3775 Out << NL; 3776 } 3777#endif 3778} 3779 3780//===----------------------------------------------------------------------===// 3781// Checker registration. 3782//===----------------------------------------------------------------------===// 3783 3784void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3785 Mgr.registerChecker<RetainCountChecker>(); 3786} 3787 3788