RetainCountChecker.cpp revision facde171ae4b8926622a1bffa833732a06f1875b
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/CheckerContext.h" 27#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 28#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" 29#include "clang/StaticAnalyzer/Core/PathSensitive/ObjCMessage.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 IncRefMsg, IncRef, MakeCollectable, MayEscape, 70 NewAutoreleasePool, SelfOwn, StopTracking }; 71 72namespace llvm { 73template <> struct FoldingSetTrait<ArgEffect> { 74static inline void Profile(const ArgEffect X, FoldingSetNodeID& ID) { 75 ID.AddInteger((unsigned) X); 76} 77}; 78} // end llvm namespace 79 80/// ArgEffects summarizes the effects of a function/method call on all of 81/// its arguments. 82typedef llvm::ImmutableMap<unsigned,ArgEffect> ArgEffects; 83 84namespace { 85 86/// RetEffect is used to summarize a function/method call's behavior with 87/// respect to its return value. 88class RetEffect { 89public: 90 enum Kind { NoRet, OwnedSymbol, OwnedAllocatedSymbol, 91 NotOwnedSymbol, GCNotOwnedSymbol, ARCNotOwnedSymbol, 92 OwnedWhenTrackedReceiver }; 93 94 enum ObjKind { CF, ObjC, AnyObj }; 95 96private: 97 Kind K; 98 ObjKind O; 99 100 RetEffect(Kind k, ObjKind o = AnyObj) : K(k), O(o) {} 101 102public: 103 Kind getKind() const { return K; } 104 105 ObjKind getObjKind() const { return O; } 106 107 bool isOwned() const { 108 return K == OwnedSymbol || K == OwnedAllocatedSymbol || 109 K == OwnedWhenTrackedReceiver; 110 } 111 112 bool operator==(const RetEffect &Other) const { 113 return K == Other.K && O == Other.O; 114 } 115 116 static RetEffect MakeOwnedWhenTrackedReceiver() { 117 return RetEffect(OwnedWhenTrackedReceiver, ObjC); 118 } 119 120 static RetEffect MakeOwned(ObjKind o, bool isAllocated = false) { 121 return RetEffect(isAllocated ? OwnedAllocatedSymbol : OwnedSymbol, o); 122 } 123 static RetEffect MakeNotOwned(ObjKind o) { 124 return RetEffect(NotOwnedSymbol, o); 125 } 126 static RetEffect MakeGCNotOwned() { 127 return RetEffect(GCNotOwnedSymbol, ObjC); 128 } 129 static RetEffect MakeARCNotOwned() { 130 return RetEffect(ARCNotOwnedSymbol, ObjC); 131 } 132 static RetEffect MakeNoRet() { 133 return RetEffect(NoRet); 134 } 135 136 void Profile(llvm::FoldingSetNodeID& ID) const { 137 ID.AddInteger((unsigned) K); 138 ID.AddInteger((unsigned) O); 139 } 140}; 141 142//===----------------------------------------------------------------------===// 143// Reference-counting logic (typestate + counts). 144//===----------------------------------------------------------------------===// 145 146class RefVal { 147public: 148 enum Kind { 149 Owned = 0, // Owning reference. 150 NotOwned, // Reference is not owned by still valid (not freed). 151 Released, // Object has been released. 152 ReturnedOwned, // Returned object passes ownership to caller. 153 ReturnedNotOwned, // Return object does not pass ownership to caller. 154 ERROR_START, 155 ErrorDeallocNotOwned, // -dealloc called on non-owned object. 156 ErrorDeallocGC, // Calling -dealloc with GC enabled. 157 ErrorUseAfterRelease, // Object used after released. 158 ErrorReleaseNotOwned, // Release of an object that was not owned. 159 ERROR_LEAK_START, 160 ErrorLeak, // A memory leak due to excessive reference counts. 161 ErrorLeakReturned, // A memory leak due to the returning method not having 162 // the correct naming conventions. 163 ErrorGCLeakReturned, 164 ErrorOverAutorelease, 165 ErrorReturnedNotOwned 166 }; 167 168private: 169 Kind kind; 170 RetEffect::ObjKind okind; 171 unsigned Cnt; 172 unsigned ACnt; 173 QualType T; 174 175 RefVal(Kind k, RetEffect::ObjKind o, unsigned cnt, unsigned acnt, QualType t) 176 : kind(k), okind(o), Cnt(cnt), ACnt(acnt), T(t) {} 177 178public: 179 Kind getKind() const { return kind; } 180 181 RetEffect::ObjKind getObjKind() const { return okind; } 182 183 unsigned getCount() const { return Cnt; } 184 unsigned getAutoreleaseCount() const { return ACnt; } 185 unsigned getCombinedCounts() const { return Cnt + ACnt; } 186 void clearCounts() { Cnt = 0; ACnt = 0; } 187 void setCount(unsigned i) { Cnt = i; } 188 void setAutoreleaseCount(unsigned i) { ACnt = i; } 189 190 QualType getType() const { return T; } 191 192 bool isOwned() const { 193 return getKind() == Owned; 194 } 195 196 bool isNotOwned() const { 197 return getKind() == NotOwned; 198 } 199 200 bool isReturnedOwned() const { 201 return getKind() == ReturnedOwned; 202 } 203 204 bool isReturnedNotOwned() const { 205 return getKind() == ReturnedNotOwned; 206 } 207 208 static RefVal makeOwned(RetEffect::ObjKind o, QualType t, 209 unsigned Count = 1) { 210 return RefVal(Owned, o, Count, 0, t); 211 } 212 213 static RefVal makeNotOwned(RetEffect::ObjKind o, QualType t, 214 unsigned Count = 0) { 215 return RefVal(NotOwned, o, Count, 0, t); 216 } 217 218 // Comparison, profiling, and pretty-printing. 219 220 bool operator==(const RefVal& X) const { 221 return kind == X.kind && Cnt == X.Cnt && T == X.T && ACnt == X.ACnt; 222 } 223 224 RefVal operator-(size_t i) const { 225 return RefVal(getKind(), getObjKind(), getCount() - i, 226 getAutoreleaseCount(), getType()); 227 } 228 229 RefVal operator+(size_t i) const { 230 return RefVal(getKind(), getObjKind(), getCount() + i, 231 getAutoreleaseCount(), getType()); 232 } 233 234 RefVal operator^(Kind k) const { 235 return RefVal(k, getObjKind(), getCount(), getAutoreleaseCount(), 236 getType()); 237 } 238 239 RefVal autorelease() const { 240 return RefVal(getKind(), getObjKind(), getCount(), getAutoreleaseCount()+1, 241 getType()); 242 } 243 244 void Profile(llvm::FoldingSetNodeID& ID) const { 245 ID.AddInteger((unsigned) kind); 246 ID.AddInteger(Cnt); 247 ID.AddInteger(ACnt); 248 ID.Add(T); 249 } 250 251 void print(raw_ostream &Out) const; 252}; 253 254void RefVal::print(raw_ostream &Out) const { 255 if (!T.isNull()) 256 Out << "Tracked " << T.getAsString() << '/'; 257 258 switch (getKind()) { 259 default: llvm_unreachable("Invalid RefVal kind"); 260 case Owned: { 261 Out << "Owned"; 262 unsigned cnt = getCount(); 263 if (cnt) Out << " (+ " << cnt << ")"; 264 break; 265 } 266 267 case NotOwned: { 268 Out << "NotOwned"; 269 unsigned cnt = getCount(); 270 if (cnt) Out << " (+ " << cnt << ")"; 271 break; 272 } 273 274 case ReturnedOwned: { 275 Out << "ReturnedOwned"; 276 unsigned cnt = getCount(); 277 if (cnt) Out << " (+ " << cnt << ")"; 278 break; 279 } 280 281 case ReturnedNotOwned: { 282 Out << "ReturnedNotOwned"; 283 unsigned cnt = getCount(); 284 if (cnt) Out << " (+ " << cnt << ")"; 285 break; 286 } 287 288 case Released: 289 Out << "Released"; 290 break; 291 292 case ErrorDeallocGC: 293 Out << "-dealloc (GC)"; 294 break; 295 296 case ErrorDeallocNotOwned: 297 Out << "-dealloc (not-owned)"; 298 break; 299 300 case ErrorLeak: 301 Out << "Leaked"; 302 break; 303 304 case ErrorLeakReturned: 305 Out << "Leaked (Bad naming)"; 306 break; 307 308 case ErrorGCLeakReturned: 309 Out << "Leaked (GC-ed at return)"; 310 break; 311 312 case ErrorUseAfterRelease: 313 Out << "Use-After-Release [ERROR]"; 314 break; 315 316 case ErrorReleaseNotOwned: 317 Out << "Release of Not-Owned [ERROR]"; 318 break; 319 320 case RefVal::ErrorOverAutorelease: 321 Out << "Over autoreleased"; 322 break; 323 324 case RefVal::ErrorReturnedNotOwned: 325 Out << "Non-owned object returned instead of owned"; 326 break; 327 } 328 329 if (ACnt) { 330 Out << " [ARC +" << ACnt << ']'; 331 } 332} 333} //end anonymous namespace 334 335//===----------------------------------------------------------------------===// 336// RefBindings - State used to track object reference counts. 337//===----------------------------------------------------------------------===// 338 339typedef llvm::ImmutableMap<SymbolRef, RefVal> RefBindings; 340 341namespace clang { 342namespace ento { 343template<> 344struct ProgramStateTrait<RefBindings> 345 : public ProgramStatePartialTrait<RefBindings> { 346 static void *GDMIndex() { 347 static int RefBIndex = 0; 348 return &RefBIndex; 349 } 350}; 351} 352} 353 354//===----------------------------------------------------------------------===// 355// Function/Method behavior summaries. 356//===----------------------------------------------------------------------===// 357 358namespace { 359class RetainSummary { 360 /// Args - a map of (index, ArgEffect) pairs, where index 361 /// specifies the argument (starting from 0). This can be sparsely 362 /// populated; arguments with no entry in Args use 'DefaultArgEffect'. 363 ArgEffects Args; 364 365 /// DefaultArgEffect - The default ArgEffect to apply to arguments that 366 /// do not have an entry in Args. 367 ArgEffect DefaultArgEffect; 368 369 /// Receiver - If this summary applies to an Objective-C message expression, 370 /// this is the effect applied to the state of the receiver. 371 ArgEffect Receiver; 372 373 /// Ret - The effect on the return value. Used to indicate if the 374 /// function/method call returns a new tracked symbol. 375 RetEffect Ret; 376 377public: 378 RetainSummary(ArgEffects A, RetEffect R, ArgEffect defaultEff, 379 ArgEffect ReceiverEff) 380 : Args(A), DefaultArgEffect(defaultEff), Receiver(ReceiverEff), Ret(R) {} 381 382 /// getArg - Return the argument effect on the argument specified by 383 /// idx (starting from 0). 384 ArgEffect getArg(unsigned idx) const { 385 if (const ArgEffect *AE = Args.lookup(idx)) 386 return *AE; 387 388 return DefaultArgEffect; 389 } 390 391 void addArg(ArgEffects::Factory &af, unsigned idx, ArgEffect e) { 392 Args = af.add(Args, idx, e); 393 } 394 395 /// setDefaultArgEffect - Set the default argument effect. 396 void setDefaultArgEffect(ArgEffect E) { 397 DefaultArgEffect = E; 398 } 399 400 /// getRetEffect - Returns the effect on the return value of the call. 401 RetEffect getRetEffect() const { return Ret; } 402 403 /// setRetEffect - Set the effect of the return value of the call. 404 void setRetEffect(RetEffect E) { Ret = E; } 405 406 407 /// Sets the effect on the receiver of the message. 408 void setReceiverEffect(ArgEffect e) { Receiver = e; } 409 410 /// getReceiverEffect - Returns the effect on the receiver of the call. 411 /// This is only meaningful if the summary applies to an ObjCMessageExpr*. 412 ArgEffect getReceiverEffect() const { return Receiver; } 413 414 /// Test if two retain summaries are identical. Note that merely equivalent 415 /// summaries are not necessarily identical (for example, if an explicit 416 /// argument effect matches the default effect). 417 bool operator==(const RetainSummary &Other) const { 418 return Args == Other.Args && DefaultArgEffect == Other.DefaultArgEffect && 419 Receiver == Other.Receiver && Ret == Other.Ret; 420 } 421 422 /// Profile this summary for inclusion in a FoldingSet. 423 void Profile(llvm::FoldingSetNodeID& ID) const { 424 ID.Add(Args); 425 ID.Add(DefaultArgEffect); 426 ID.Add(Receiver); 427 ID.Add(Ret); 428 } 429 430 /// A retain summary is simple if it has no ArgEffects other than the default. 431 bool isSimple() const { 432 return Args.isEmpty(); 433 } 434}; 435} // end anonymous namespace 436 437//===----------------------------------------------------------------------===// 438// Data structures for constructing summaries. 439//===----------------------------------------------------------------------===// 440 441namespace { 442class ObjCSummaryKey { 443 IdentifierInfo* II; 444 Selector S; 445public: 446 ObjCSummaryKey(IdentifierInfo* ii, Selector s) 447 : II(ii), S(s) {} 448 449 ObjCSummaryKey(const ObjCInterfaceDecl *d, Selector s) 450 : II(d ? d->getIdentifier() : 0), S(s) {} 451 452 ObjCSummaryKey(const ObjCInterfaceDecl *d, IdentifierInfo *ii, Selector s) 453 : II(d ? d->getIdentifier() : ii), S(s) {} 454 455 ObjCSummaryKey(Selector s) 456 : II(0), S(s) {} 457 458 IdentifierInfo *getIdentifier() const { return II; } 459 Selector getSelector() const { return S; } 460}; 461} 462 463namespace llvm { 464template <> struct DenseMapInfo<ObjCSummaryKey> { 465 static inline ObjCSummaryKey getEmptyKey() { 466 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getEmptyKey(), 467 DenseMapInfo<Selector>::getEmptyKey()); 468 } 469 470 static inline ObjCSummaryKey getTombstoneKey() { 471 return ObjCSummaryKey(DenseMapInfo<IdentifierInfo*>::getTombstoneKey(), 472 DenseMapInfo<Selector>::getTombstoneKey()); 473 } 474 475 static unsigned getHashValue(const ObjCSummaryKey &V) { 476 typedef std::pair<IdentifierInfo*, Selector> PairTy; 477 return DenseMapInfo<PairTy>::getHashValue(PairTy(V.getIdentifier(), 478 V.getSelector())); 479 } 480 481 static bool isEqual(const ObjCSummaryKey& LHS, const ObjCSummaryKey& RHS) { 482 return LHS.getIdentifier() == RHS.getIdentifier() && 483 LHS.getSelector() == RHS.getSelector(); 484 } 485 486}; 487template <> 488struct isPodLike<ObjCSummaryKey> { static const bool value = true; }; 489} // end llvm namespace 490 491namespace { 492class ObjCSummaryCache { 493 typedef llvm::DenseMap<ObjCSummaryKey, const RetainSummary *> MapTy; 494 MapTy M; 495public: 496 ObjCSummaryCache() {} 497 498 const RetainSummary * find(const ObjCInterfaceDecl *D, IdentifierInfo *ClsName, 499 Selector S) { 500 // Lookup the method using the decl for the class @interface. If we 501 // have no decl, lookup using the class name. 502 return D ? find(D, S) : find(ClsName, S); 503 } 504 505 const RetainSummary * find(const ObjCInterfaceDecl *D, Selector S) { 506 // Do a lookup with the (D,S) pair. If we find a match return 507 // the iterator. 508 ObjCSummaryKey K(D, S); 509 MapTy::iterator I = M.find(K); 510 511 if (I != M.end() || !D) 512 return I->second; 513 514 // Walk the super chain. If we find a hit with a parent, we'll end 515 // up returning that summary. We actually allow that key (null,S), as 516 // we cache summaries for the null ObjCInterfaceDecl* to allow us to 517 // generate initial summaries without having to worry about NSObject 518 // being declared. 519 // FIXME: We may change this at some point. 520 for (ObjCInterfaceDecl *C=D->getSuperClass() ;; C=C->getSuperClass()) { 521 if ((I = M.find(ObjCSummaryKey(C, S))) != M.end()) 522 break; 523 524 if (!C) 525 return NULL; 526 } 527 528 // Cache the summary with original key to make the next lookup faster 529 // and return the iterator. 530 const RetainSummary *Summ = I->second; 531 M[K] = Summ; 532 return Summ; 533 } 534 535 const RetainSummary *find(IdentifierInfo* II, Selector S) { 536 // FIXME: Class method lookup. Right now we dont' have a good way 537 // of going between IdentifierInfo* and the class hierarchy. 538 MapTy::iterator I = M.find(ObjCSummaryKey(II, S)); 539 540 if (I == M.end()) 541 I = M.find(ObjCSummaryKey(S)); 542 543 return I == M.end() ? NULL : I->second; 544 } 545 546 const RetainSummary *& operator[](ObjCSummaryKey K) { 547 return M[K]; 548 } 549 550 const RetainSummary *& operator[](Selector S) { 551 return M[ ObjCSummaryKey(S) ]; 552 } 553}; 554} // end anonymous namespace 555 556//===----------------------------------------------------------------------===// 557// Data structures for managing collections of summaries. 558//===----------------------------------------------------------------------===// 559 560namespace { 561class RetainSummaryManager { 562 563 //==-----------------------------------------------------------------==// 564 // Typedefs. 565 //==-----------------------------------------------------------------==// 566 567 typedef llvm::DenseMap<const FunctionDecl*, const RetainSummary *> 568 FuncSummariesTy; 569 570 typedef ObjCSummaryCache ObjCMethodSummariesTy; 571 572 typedef llvm::FoldingSetNodeWrapper<RetainSummary> CachedSummaryNode; 573 574 //==-----------------------------------------------------------------==// 575 // Data. 576 //==-----------------------------------------------------------------==// 577 578 /// Ctx - The ASTContext object for the analyzed ASTs. 579 ASTContext &Ctx; 580 581 /// GCEnabled - Records whether or not the analyzed code runs in GC mode. 582 const bool GCEnabled; 583 584 /// Records whether or not the analyzed code runs in ARC mode. 585 const bool ARCEnabled; 586 587 /// FuncSummaries - A map from FunctionDecls to summaries. 588 FuncSummariesTy FuncSummaries; 589 590 /// ObjCClassMethodSummaries - A map from selectors (for instance methods) 591 /// to summaries. 592 ObjCMethodSummariesTy ObjCClassMethodSummaries; 593 594 /// ObjCMethodSummaries - A map from selectors to summaries. 595 ObjCMethodSummariesTy ObjCMethodSummaries; 596 597 /// BPAlloc - A BumpPtrAllocator used for allocating summaries, ArgEffects, 598 /// and all other data used by the checker. 599 llvm::BumpPtrAllocator BPAlloc; 600 601 /// AF - A factory for ArgEffects objects. 602 ArgEffects::Factory AF; 603 604 /// ScratchArgs - A holding buffer for construct ArgEffects. 605 ArgEffects ScratchArgs; 606 607 /// ObjCAllocRetE - Default return effect for methods returning Objective-C 608 /// objects. 609 RetEffect ObjCAllocRetE; 610 611 /// ObjCInitRetE - Default return effect for init methods returning 612 /// Objective-C objects. 613 RetEffect ObjCInitRetE; 614 615 /// SimpleSummaries - Used for uniquing summaries that don't have special 616 /// effects. 617 llvm::FoldingSet<CachedSummaryNode> SimpleSummaries; 618 619 //==-----------------------------------------------------------------==// 620 // Methods. 621 //==-----------------------------------------------------------------==// 622 623 /// getArgEffects - Returns a persistent ArgEffects object based on the 624 /// data in ScratchArgs. 625 ArgEffects getArgEffects(); 626 627 enum UnaryFuncKind { cfretain, cfrelease, cfmakecollectable }; 628 629public: 630 RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; } 631 632 const RetainSummary *getUnarySummary(const FunctionType* FT, 633 UnaryFuncKind func); 634 635 const RetainSummary *getCFSummaryCreateRule(const FunctionDecl *FD); 636 const RetainSummary *getCFSummaryGetRule(const FunctionDecl *FD); 637 const RetainSummary *getCFCreateGetRuleSummary(const FunctionDecl *FD); 638 639 const RetainSummary *getPersistentSummary(const RetainSummary &OldSumm); 640 641 const RetainSummary *getPersistentSummary(RetEffect RetEff, 642 ArgEffect ReceiverEff = DoNothing, 643 ArgEffect DefaultEff = MayEscape) { 644 RetainSummary Summ(getArgEffects(), RetEff, DefaultEff, ReceiverEff); 645 return getPersistentSummary(Summ); 646 } 647 648 const RetainSummary *getDoNothingSummary() { 649 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 650 } 651 652 const RetainSummary *getDefaultSummary() { 653 return getPersistentSummary(RetEffect::MakeNoRet(), 654 DoNothing, MayEscape); 655 } 656 657 const RetainSummary *getPersistentStopSummary() { 658 return getPersistentSummary(RetEffect::MakeNoRet(), 659 StopTracking, StopTracking); 660 } 661 662 void InitializeClassMethodSummaries(); 663 void InitializeMethodSummaries(); 664private: 665 void addNSObjectClsMethSummary(Selector S, const RetainSummary *Summ) { 666 ObjCClassMethodSummaries[S] = Summ; 667 } 668 669 void addNSObjectMethSummary(Selector S, const RetainSummary *Summ) { 670 ObjCMethodSummaries[S] = Summ; 671 } 672 673 void addClassMethSummary(const char* Cls, const char* name, 674 const RetainSummary *Summ, bool isNullary = true) { 675 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 676 Selector S = isNullary ? GetNullarySelector(name, Ctx) 677 : GetUnarySelector(name, Ctx); 678 ObjCClassMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 679 } 680 681 void addInstMethSummary(const char* Cls, const char* nullaryName, 682 const RetainSummary *Summ) { 683 IdentifierInfo* ClsII = &Ctx.Idents.get(Cls); 684 Selector S = GetNullarySelector(nullaryName, Ctx); 685 ObjCMethodSummaries[ObjCSummaryKey(ClsII, S)] = Summ; 686 } 687 688 Selector generateSelector(va_list argp) { 689 SmallVector<IdentifierInfo*, 10> II; 690 691 while (const char* s = va_arg(argp, const char*)) 692 II.push_back(&Ctx.Idents.get(s)); 693 694 return Ctx.Selectors.getSelector(II.size(), &II[0]); 695 } 696 697 void addMethodSummary(IdentifierInfo *ClsII, ObjCMethodSummariesTy& Summaries, 698 const RetainSummary * Summ, va_list argp) { 699 Selector S = generateSelector(argp); 700 Summaries[ObjCSummaryKey(ClsII, S)] = Summ; 701 } 702 703 void addInstMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 704 va_list argp; 705 va_start(argp, Summ); 706 addMethodSummary(&Ctx.Idents.get(Cls), ObjCMethodSummaries, Summ, argp); 707 va_end(argp); 708 } 709 710 void addClsMethSummary(const char* Cls, const RetainSummary * Summ, ...) { 711 va_list argp; 712 va_start(argp, Summ); 713 addMethodSummary(&Ctx.Idents.get(Cls),ObjCClassMethodSummaries, Summ, argp); 714 va_end(argp); 715 } 716 717 void addClsMethSummary(IdentifierInfo *II, const RetainSummary * Summ, ...) { 718 va_list argp; 719 va_start(argp, Summ); 720 addMethodSummary(II, ObjCClassMethodSummaries, Summ, argp); 721 va_end(argp); 722 } 723 724public: 725 726 RetainSummaryManager(ASTContext &ctx, bool gcenabled, bool usesARC) 727 : Ctx(ctx), 728 GCEnabled(gcenabled), 729 ARCEnabled(usesARC), 730 AF(BPAlloc), ScratchArgs(AF.getEmptyMap()), 731 ObjCAllocRetE(gcenabled 732 ? RetEffect::MakeGCNotOwned() 733 : (usesARC ? RetEffect::MakeARCNotOwned() 734 : RetEffect::MakeOwned(RetEffect::ObjC, true))), 735 ObjCInitRetE(gcenabled 736 ? RetEffect::MakeGCNotOwned() 737 : (usesARC ? RetEffect::MakeARCNotOwned() 738 : RetEffect::MakeOwnedWhenTrackedReceiver())) { 739 InitializeClassMethodSummaries(); 740 InitializeMethodSummaries(); 741 } 742 743 const RetainSummary *getSummary(const FunctionDecl *FD, 744 const CallOrObjCMessage *CME = 0); 745 746 const RetainSummary *getMethodSummary(Selector S, IdentifierInfo *ClsName, 747 const ObjCInterfaceDecl *ID, 748 const ObjCMethodDecl *MD, 749 QualType RetTy, 750 ObjCMethodSummariesTy &CachedSummaries); 751 752 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 753 ProgramStateRef state, 754 const LocationContext *LC); 755 756 const RetainSummary *getInstanceMethodSummary(const ObjCMessage &msg, 757 const ObjCInterfaceDecl *ID) { 758 return getMethodSummary(msg.getSelector(), 0, ID, msg.getMethodDecl(), 759 msg.getType(Ctx), ObjCMethodSummaries); 760 } 761 762 const RetainSummary *getClassMethodSummary(const ObjCMessage &msg) { 763 const ObjCInterfaceDecl *Class = 0; 764 if (!msg.isInstanceMessage()) 765 Class = msg.getReceiverInterface(); 766 767 return getMethodSummary(msg.getSelector(), Class->getIdentifier(), 768 Class, msg.getMethodDecl(), msg.getType(Ctx), 769 ObjCClassMethodSummaries); 770 } 771 772 /// getMethodSummary - This version of getMethodSummary is used to query 773 /// the summary for the current method being analyzed. 774 const RetainSummary *getMethodSummary(const ObjCMethodDecl *MD) { 775 // FIXME: Eventually this should be unneeded. 776 const ObjCInterfaceDecl *ID = MD->getClassInterface(); 777 Selector S = MD->getSelector(); 778 IdentifierInfo *ClsName = ID->getIdentifier(); 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, ClsName, 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 bool isGCEnabled() const { return GCEnabled; } 800 801 bool isARCEnabled() const { return ARCEnabled; } 802 803 bool isARCorGCEnabled() const { return GCEnabled || ARCEnabled; } 804}; 805 806// Used to avoid allocating long-term (BPAlloc'd) memory for default retain 807// summaries. If a function or method looks like it has a default summary, but 808// it has annotations, the annotations are added to the stack-based template 809// and then copied into managed memory. 810class RetainSummaryTemplate { 811 RetainSummaryManager &Manager; 812 const RetainSummary *&RealSummary; 813 RetainSummary ScratchSummary; 814 bool Accessed; 815public: 816 RetainSummaryTemplate(const RetainSummary *&real, const RetainSummary &base, 817 RetainSummaryManager &mgr) 818 : Manager(mgr), RealSummary(real), ScratchSummary(real ? *real : base), 819 Accessed(false) {} 820 821 ~RetainSummaryTemplate() { 822 if (Accessed) 823 RealSummary = Manager.getPersistentSummary(ScratchSummary); 824 } 825 826 RetainSummary &operator*() { 827 Accessed = true; 828 return ScratchSummary; 829 } 830 831 RetainSummary *operator->() { 832 Accessed = true; 833 return &ScratchSummary; 834 } 835}; 836 837} // end anonymous namespace 838 839//===----------------------------------------------------------------------===// 840// Implementation of checker data structures. 841//===----------------------------------------------------------------------===// 842 843ArgEffects RetainSummaryManager::getArgEffects() { 844 ArgEffects AE = ScratchArgs; 845 ScratchArgs = AF.getEmptyMap(); 846 return AE; 847} 848 849const RetainSummary * 850RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) { 851 // Unique "simple" summaries -- those without ArgEffects. 852 if (OldSumm.isSimple()) { 853 llvm::FoldingSetNodeID ID; 854 OldSumm.Profile(ID); 855 856 void *Pos; 857 CachedSummaryNode *N = SimpleSummaries.FindNodeOrInsertPos(ID, Pos); 858 859 if (!N) { 860 N = (CachedSummaryNode *) BPAlloc.Allocate<CachedSummaryNode>(); 861 new (N) CachedSummaryNode(OldSumm); 862 SimpleSummaries.InsertNode(N, Pos); 863 } 864 865 return &N->getValue(); 866 } 867 868 RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>(); 869 new (Summ) RetainSummary(OldSumm); 870 return Summ; 871} 872 873//===----------------------------------------------------------------------===// 874// Summary creation for functions (largely uses of Core Foundation). 875//===----------------------------------------------------------------------===// 876 877static bool isRetain(const FunctionDecl *FD, StringRef FName) { 878 return FName.endswith("Retain"); 879} 880 881static bool isRelease(const FunctionDecl *FD, StringRef FName) { 882 return FName.endswith("Release"); 883} 884 885static bool isMakeCollectable(const FunctionDecl *FD, StringRef FName) { 886 // FIXME: Remove FunctionDecl parameter. 887 // FIXME: Is it really okay if MakeCollectable isn't a suffix? 888 return FName.find("MakeCollectable") != StringRef::npos; 889} 890 891const RetainSummary * 892RetainSummaryManager::getSummary(const FunctionDecl *FD, 893 const CallOrObjCMessage *CME) { 894 // Look up a summary in our cache of FunctionDecls -> Summaries. 895 FuncSummariesTy::iterator I = FuncSummaries.find(FD); 896 if (I != FuncSummaries.end()) 897 return I->second; 898 899 // No summary? Generate one. 900 const RetainSummary *S = 0; 901 902 do { 903 // We generate "stop" summaries for implicitly defined functions. 904 if (FD->isImplicit()) { 905 S = getPersistentStopSummary(); 906 break; 907 } 908 // For C++ methods, generate an implicit "stop" summary as well. We 909 // can relax this once we have a clear policy for C++ methods and 910 // ownership attributes. 911 if (isa<CXXMethodDecl>(FD)) { 912 S = getPersistentStopSummary(); 913 break; 914 } 915 916 // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the 917 // function's type. 918 const FunctionType* FT = FD->getType()->getAs<FunctionType>(); 919 const IdentifierInfo *II = FD->getIdentifier(); 920 if (!II) 921 break; 922 923 StringRef FName = II->getName(); 924 925 // Strip away preceding '_'. Doing this here will effect all the checks 926 // down below. 927 FName = FName.substr(FName.find_first_not_of('_')); 928 929 // Inspect the result type. 930 QualType RetTy = FT->getResultType(); 931 932 // FIXME: This should all be refactored into a chain of "summary lookup" 933 // filters. 934 assert(ScratchArgs.isEmpty()); 935 936 if (FName == "pthread_create" || FName == "pthread_setspecific") { 937 // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>. 938 // This will be addressed better with IPA. 939 S = getPersistentStopSummary(); 940 } else if (FName == "NSMakeCollectable") { 941 // Handle: id NSMakeCollectable(CFTypeRef) 942 S = (RetTy->isObjCIdType()) 943 ? getUnarySummary(FT, cfmakecollectable) 944 : getPersistentStopSummary(); 945 } else if (FName == "IOBSDNameMatching" || 946 FName == "IOServiceMatching" || 947 FName == "IOServiceNameMatching" || 948 FName == "IORegistryEntrySearchCFProperty" || 949 FName == "IORegistryEntryIDMatching" || 950 FName == "IOOpenFirmwarePathMatching") { 951 // Part of <rdar://problem/6961230>. (IOKit) 952 // This should be addressed using a API table. 953 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 954 DoNothing, DoNothing); 955 } else if (FName == "IOServiceGetMatchingService" || 956 FName == "IOServiceGetMatchingServices") { 957 // FIXES: <rdar://problem/6326900> 958 // This should be addressed using a API table. This strcmp is also 959 // a little gross, but there is no need to super optimize here. 960 ScratchArgs = AF.add(ScratchArgs, 1, DecRef); 961 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 962 } else if (FName == "IOServiceAddNotification" || 963 FName == "IOServiceAddMatchingNotification") { 964 // Part of <rdar://problem/6961230>. (IOKit) 965 // This should be addressed using a API table. 966 ScratchArgs = AF.add(ScratchArgs, 2, DecRef); 967 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 968 } else if (FName == "CVPixelBufferCreateWithBytes") { 969 // FIXES: <rdar://problem/7283567> 970 // Eventually this can be improved by recognizing that the pixel 971 // buffer passed to CVPixelBufferCreateWithBytes is released via 972 // a callback and doing full IPA to make sure this is done correctly. 973 // FIXME: This function has an out parameter that returns an 974 // allocated object. 975 ScratchArgs = AF.add(ScratchArgs, 7, StopTracking); 976 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 977 } else if (FName == "CGBitmapContextCreateWithData") { 978 // FIXES: <rdar://problem/7358899> 979 // Eventually this can be improved by recognizing that 'releaseInfo' 980 // passed to CGBitmapContextCreateWithData is released via 981 // a callback and doing full IPA to make sure this is done correctly. 982 ScratchArgs = AF.add(ScratchArgs, 8, StopTracking); 983 S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true), 984 DoNothing, DoNothing); 985 } else if (FName == "CVPixelBufferCreateWithPlanarBytes") { 986 // FIXES: <rdar://problem/7283567> 987 // Eventually this can be improved by recognizing that the pixel 988 // buffer passed to CVPixelBufferCreateWithPlanarBytes is released 989 // via a callback and doing full IPA to make sure this is done 990 // correctly. 991 ScratchArgs = AF.add(ScratchArgs, 12, StopTracking); 992 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 993 } else if (FName == "dispatch_set_context") { 994 // <rdar://problem/11059275> - The analyzer currently doesn't have 995 // a good way to reason about the finalizer function for libdispatch. 996 // If we pass a context object that is memory managed, stop tracking it. 997 // FIXME: this hack should possibly go away once we can handle 998 // libdispatch finalizers. 999 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1000 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1001 } else if (FName.startswith("NSLog")) { 1002 S = getDoNothingSummary(); 1003 } else if (FName.startswith("NS") && 1004 (FName.find("Insert") != StringRef::npos)) { 1005 // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can 1006 // be deallocated by NSMapRemove. (radar://11152419) 1007 ScratchArgs = AF.add(ScratchArgs, 1, StopTracking); 1008 ScratchArgs = AF.add(ScratchArgs, 2, StopTracking); 1009 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1010 } else if (CME && CME->hasNonZeroCallbackArg()) { 1011 // Allow objects to escape through callbacks. radar://10973977 1012 S = getPersistentStopSummary(); 1013 } 1014 1015 // Did we get a summary? 1016 if (S) 1017 break; 1018 1019 // Enable this code once the semantics of NSDeallocateObject are resolved 1020 // for GC. <rdar://problem/6619988> 1021#if 0 1022 // Handle: NSDeallocateObject(id anObject); 1023 // This method does allow 'nil' (although we don't check it now). 1024 if (strcmp(FName, "NSDeallocateObject") == 0) { 1025 return RetTy == Ctx.VoidTy 1026 ? getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, Dealloc) 1027 : getPersistentStopSummary(); 1028 } 1029#endif 1030 1031 if (RetTy->isPointerType()) { 1032 // For CoreFoundation ('CF') types. 1033 if (cocoa::isRefType(RetTy, "CF", FName)) { 1034 if (isRetain(FD, FName)) 1035 S = getUnarySummary(FT, cfretain); 1036 else if (isMakeCollectable(FD, FName)) 1037 S = getUnarySummary(FT, cfmakecollectable); 1038 else 1039 S = getCFCreateGetRuleSummary(FD); 1040 1041 break; 1042 } 1043 1044 // For CoreGraphics ('CG') types. 1045 if (cocoa::isRefType(RetTy, "CG", FName)) { 1046 if (isRetain(FD, FName)) 1047 S = getUnarySummary(FT, cfretain); 1048 else 1049 S = getCFCreateGetRuleSummary(FD); 1050 1051 break; 1052 } 1053 1054 // For the Disk Arbitration API (DiskArbitration/DADisk.h) 1055 if (cocoa::isRefType(RetTy, "DADisk") || 1056 cocoa::isRefType(RetTy, "DADissenter") || 1057 cocoa::isRefType(RetTy, "DASessionRef")) { 1058 S = getCFCreateGetRuleSummary(FD); 1059 break; 1060 } 1061 1062 break; 1063 } 1064 1065 // Check for release functions, the only kind of functions that we care 1066 // about that don't return a pointer type. 1067 if (FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) { 1068 // Test for 'CGCF'. 1069 FName = FName.substr(FName.startswith("CGCF") ? 4 : 2); 1070 1071 if (isRelease(FD, FName)) 1072 S = getUnarySummary(FT, cfrelease); 1073 else { 1074 assert (ScratchArgs.isEmpty()); 1075 // Remaining CoreFoundation and CoreGraphics functions. 1076 // We use to assume that they all strictly followed the ownership idiom 1077 // and that ownership cannot be transferred. While this is technically 1078 // correct, many methods allow a tracked object to escape. For example: 1079 // 1080 // CFMutableDictionaryRef x = CFDictionaryCreateMutable(...); 1081 // CFDictionaryAddValue(y, key, x); 1082 // CFRelease(x); 1083 // ... it is okay to use 'x' since 'y' has a reference to it 1084 // 1085 // We handle this and similar cases with the follow heuristic. If the 1086 // function name contains "InsertValue", "SetValue", "AddValue", 1087 // "AppendValue", or "SetAttribute", then we assume that arguments may 1088 // "escape." This means that something else holds on to the object, 1089 // allowing it be used even after its local retain count drops to 0. 1090 ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos|| 1091 StrInStrNoCase(FName, "AddValue") != StringRef::npos || 1092 StrInStrNoCase(FName, "SetValue") != StringRef::npos || 1093 StrInStrNoCase(FName, "AppendValue") != StringRef::npos|| 1094 StrInStrNoCase(FName, "SetAttribute") != StringRef::npos) 1095 ? MayEscape : DoNothing; 1096 1097 S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E); 1098 } 1099 } 1100 } 1101 while (0); 1102 1103 // Annotations override defaults. 1104 updateSummaryFromAnnotations(S, FD); 1105 1106 FuncSummaries[FD] = S; 1107 return S; 1108} 1109 1110const RetainSummary * 1111RetainSummaryManager::getCFCreateGetRuleSummary(const FunctionDecl *FD) { 1112 if (coreFoundation::followsCreateRule(FD)) 1113 return getCFSummaryCreateRule(FD); 1114 1115 return getCFSummaryGetRule(FD); 1116} 1117 1118const RetainSummary * 1119RetainSummaryManager::getUnarySummary(const FunctionType* FT, 1120 UnaryFuncKind func) { 1121 1122 // Sanity check that this is *really* a unary function. This can 1123 // happen if people do weird things. 1124 const FunctionProtoType* FTP = dyn_cast<FunctionProtoType>(FT); 1125 if (!FTP || FTP->getNumArgs() != 1) 1126 return getPersistentStopSummary(); 1127 1128 assert (ScratchArgs.isEmpty()); 1129 1130 ArgEffect Effect; 1131 switch (func) { 1132 case cfretain: Effect = IncRef; break; 1133 case cfrelease: Effect = DecRef; break; 1134 case cfmakecollectable: Effect = MakeCollectable; break; 1135 } 1136 1137 ScratchArgs = AF.add(ScratchArgs, 0, Effect); 1138 return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing); 1139} 1140 1141const RetainSummary * 1142RetainSummaryManager::getCFSummaryCreateRule(const FunctionDecl *FD) { 1143 assert (ScratchArgs.isEmpty()); 1144 1145 return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1146} 1147 1148const RetainSummary * 1149RetainSummaryManager::getCFSummaryGetRule(const FunctionDecl *FD) { 1150 assert (ScratchArgs.isEmpty()); 1151 return getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::CF), 1152 DoNothing, DoNothing); 1153} 1154 1155//===----------------------------------------------------------------------===// 1156// Summary creation for Selectors. 1157//===----------------------------------------------------------------------===// 1158 1159void 1160RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1161 const FunctionDecl *FD) { 1162 if (!FD) 1163 return; 1164 1165 RetainSummaryTemplate Template(Summ, *getDefaultSummary(), *this); 1166 1167 // Effects on the parameters. 1168 unsigned parm_idx = 0; 1169 for (FunctionDecl::param_const_iterator pi = FD->param_begin(), 1170 pe = FD->param_end(); pi != pe; ++pi, ++parm_idx) { 1171 const ParmVarDecl *pd = *pi; 1172 if (pd->getAttr<NSConsumedAttr>()) { 1173 if (!GCEnabled) { 1174 Template->addArg(AF, parm_idx, DecRef); 1175 } 1176 } else if (pd->getAttr<CFConsumedAttr>()) { 1177 Template->addArg(AF, parm_idx, DecRef); 1178 } 1179 } 1180 1181 QualType RetTy = FD->getResultType(); 1182 1183 // Determine if there is a special return effect for this method. 1184 if (cocoa::isCocoaObjectRef(RetTy)) { 1185 if (FD->getAttr<NSReturnsRetainedAttr>()) { 1186 Template->setRetEffect(ObjCAllocRetE); 1187 } 1188 else if (FD->getAttr<CFReturnsRetainedAttr>()) { 1189 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1190 } 1191 else if (FD->getAttr<NSReturnsNotRetainedAttr>()) { 1192 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1193 } 1194 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1195 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1196 } 1197 } else if (RetTy->getAs<PointerType>()) { 1198 if (FD->getAttr<CFReturnsRetainedAttr>()) { 1199 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1200 } 1201 else if (FD->getAttr<CFReturnsNotRetainedAttr>()) { 1202 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1203 } 1204 } 1205} 1206 1207void 1208RetainSummaryManager::updateSummaryFromAnnotations(const RetainSummary *&Summ, 1209 const ObjCMethodDecl *MD) { 1210 if (!MD) 1211 return; 1212 1213 RetainSummaryTemplate Template(Summ, *getDefaultSummary(), *this); 1214 bool isTrackedLoc = false; 1215 1216 // Effects on the receiver. 1217 if (MD->getAttr<NSConsumesSelfAttr>()) { 1218 if (!GCEnabled) 1219 Template->setReceiverEffect(DecRefMsg); 1220 } 1221 1222 // Effects on the parameters. 1223 unsigned parm_idx = 0; 1224 for (ObjCMethodDecl::param_const_iterator 1225 pi=MD->param_begin(), pe=MD->param_end(); 1226 pi != pe; ++pi, ++parm_idx) { 1227 const ParmVarDecl *pd = *pi; 1228 if (pd->getAttr<NSConsumedAttr>()) { 1229 if (!GCEnabled) 1230 Template->addArg(AF, parm_idx, DecRef); 1231 } 1232 else if(pd->getAttr<CFConsumedAttr>()) { 1233 Template->addArg(AF, parm_idx, DecRef); 1234 } 1235 } 1236 1237 // Determine if there is a special return effect for this method. 1238 if (cocoa::isCocoaObjectRef(MD->getResultType())) { 1239 if (MD->getAttr<NSReturnsRetainedAttr>()) { 1240 Template->setRetEffect(ObjCAllocRetE); 1241 return; 1242 } 1243 if (MD->getAttr<NSReturnsNotRetainedAttr>()) { 1244 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::ObjC)); 1245 return; 1246 } 1247 1248 isTrackedLoc = true; 1249 } else { 1250 isTrackedLoc = MD->getResultType()->getAs<PointerType>() != NULL; 1251 } 1252 1253 if (isTrackedLoc) { 1254 if (MD->getAttr<CFReturnsRetainedAttr>()) 1255 Template->setRetEffect(RetEffect::MakeOwned(RetEffect::CF, true)); 1256 else if (MD->getAttr<CFReturnsNotRetainedAttr>()) 1257 Template->setRetEffect(RetEffect::MakeNotOwned(RetEffect::CF)); 1258 } 1259} 1260 1261const RetainSummary * 1262RetainSummaryManager::getStandardMethodSummary(const ObjCMethodDecl *MD, 1263 Selector S, QualType RetTy) { 1264 1265 if (MD) { 1266 // Scan the method decl for 'void*' arguments. These should be treated 1267 // as 'StopTracking' because they are often used with delegates. 1268 // Delegates are a frequent form of false positives with the retain 1269 // count checker. 1270 unsigned i = 0; 1271 for (ObjCMethodDecl::param_const_iterator I = MD->param_begin(), 1272 E = MD->param_end(); I != E; ++I, ++i) 1273 if (const ParmVarDecl *PD = *I) { 1274 QualType Ty = Ctx.getCanonicalType(PD->getType()); 1275 if (Ty.getLocalUnqualifiedType() == Ctx.VoidPtrTy) 1276 ScratchArgs = AF.add(ScratchArgs, i, StopTracking); 1277 } 1278 } 1279 1280 // Any special effects? 1281 ArgEffect ReceiverEff = DoNothing; 1282 RetEffect ResultEff = RetEffect::MakeNoRet(); 1283 1284 // Check the method family, and apply any default annotations. 1285 switch (MD ? MD->getMethodFamily() : S.getMethodFamily()) { 1286 case OMF_None: 1287 case OMF_performSelector: 1288 // Assume all Objective-C methods follow Cocoa Memory Management rules. 1289 // FIXME: Does the non-threaded performSelector family really belong here? 1290 // The selector could be, say, @selector(copy). 1291 if (cocoa::isCocoaObjectRef(RetTy)) 1292 ResultEff = RetEffect::MakeNotOwned(RetEffect::ObjC); 1293 else if (coreFoundation::isCFObjectRef(RetTy)) { 1294 // ObjCMethodDecl currently doesn't consider CF objects as valid return 1295 // values for alloc, new, copy, or mutableCopy, so we have to 1296 // double-check with the selector. This is ugly, but there aren't that 1297 // many Objective-C methods that return CF objects, right? 1298 if (MD) { 1299 switch (S.getMethodFamily()) { 1300 case OMF_alloc: 1301 case OMF_new: 1302 case OMF_copy: 1303 case OMF_mutableCopy: 1304 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1305 break; 1306 default: 1307 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1308 break; 1309 } 1310 } else { 1311 ResultEff = RetEffect::MakeNotOwned(RetEffect::CF); 1312 } 1313 } 1314 break; 1315 case OMF_init: 1316 ResultEff = ObjCInitRetE; 1317 ReceiverEff = DecRefMsg; 1318 break; 1319 case OMF_alloc: 1320 case OMF_new: 1321 case OMF_copy: 1322 case OMF_mutableCopy: 1323 if (cocoa::isCocoaObjectRef(RetTy)) 1324 ResultEff = ObjCAllocRetE; 1325 else if (coreFoundation::isCFObjectRef(RetTy)) 1326 ResultEff = RetEffect::MakeOwned(RetEffect::CF, true); 1327 break; 1328 case OMF_autorelease: 1329 ReceiverEff = Autorelease; 1330 break; 1331 case OMF_retain: 1332 ReceiverEff = IncRefMsg; 1333 break; 1334 case OMF_release: 1335 ReceiverEff = DecRefMsg; 1336 break; 1337 case OMF_dealloc: 1338 ReceiverEff = Dealloc; 1339 break; 1340 case OMF_self: 1341 // -self is handled specially by the ExprEngine to propagate the receiver. 1342 break; 1343 case OMF_retainCount: 1344 case OMF_finalize: 1345 // These methods don't return objects. 1346 break; 1347 } 1348 1349 // If one of the arguments in the selector has the keyword 'delegate' we 1350 // should stop tracking the reference count for the receiver. This is 1351 // because the reference count is quite possibly handled by a delegate 1352 // method. 1353 if (S.isKeywordSelector()) { 1354 const std::string &str = S.getAsString(); 1355 assert(!str.empty()); 1356 if (StrInStrNoCase(str, "delegate:") != StringRef::npos) 1357 ReceiverEff = StopTracking; 1358 } 1359 1360 if (ScratchArgs.isEmpty() && ReceiverEff == DoNothing && 1361 ResultEff.getKind() == RetEffect::NoRet) 1362 return getDefaultSummary(); 1363 1364 return getPersistentSummary(ResultEff, ReceiverEff, MayEscape); 1365} 1366 1367const RetainSummary * 1368RetainSummaryManager::getInstanceMethodSummary(const ObjCMessage &msg, 1369 ProgramStateRef state, 1370 const LocationContext *LC) { 1371 1372 // We need the type-information of the tracked receiver object 1373 // Retrieve it from the state. 1374 const Expr *Receiver = msg.getInstanceReceiver(); 1375 const ObjCInterfaceDecl *ID = 0; 1376 1377 // FIXME: Is this really working as expected? There are cases where 1378 // we just use the 'ID' from the message expression. 1379 SVal receiverV; 1380 1381 if (Receiver) { 1382 receiverV = state->getSValAsScalarOrLoc(Receiver, LC); 1383 1384 // FIXME: Eventually replace the use of state->get<RefBindings> with 1385 // a generic API for reasoning about the Objective-C types of symbolic 1386 // objects. 1387 if (SymbolRef Sym = receiverV.getAsLocSymbol()) 1388 if (const RefVal *T = state->get<RefBindings>(Sym)) 1389 if (const ObjCObjectPointerType* PT = 1390 T->getType()->getAs<ObjCObjectPointerType>()) 1391 ID = PT->getInterfaceDecl(); 1392 1393 // FIXME: this is a hack. This may or may not be the actual method 1394 // that is called. 1395 if (!ID) { 1396 if (const ObjCObjectPointerType *PT = 1397 Receiver->getType()->getAs<ObjCObjectPointerType>()) 1398 ID = PT->getInterfaceDecl(); 1399 } 1400 } else { 1401 // FIXME: Hack for 'super'. 1402 ID = msg.getReceiverInterface(); 1403 } 1404 1405 // FIXME: The receiver could be a reference to a class, meaning that 1406 // we should use the class method. 1407 return getInstanceMethodSummary(msg, ID); 1408} 1409 1410const RetainSummary * 1411RetainSummaryManager::getMethodSummary(Selector S, IdentifierInfo *ClsName, 1412 const ObjCInterfaceDecl *ID, 1413 const ObjCMethodDecl *MD, QualType RetTy, 1414 ObjCMethodSummariesTy &CachedSummaries) { 1415 1416 // Look up a summary in our summary cache. 1417 const RetainSummary *Summ = CachedSummaries.find(ID, ClsName, S); 1418 1419 if (!Summ) { 1420 Summ = getStandardMethodSummary(MD, S, RetTy); 1421 1422 // Annotations override defaults. 1423 updateSummaryFromAnnotations(Summ, MD); 1424 1425 // Memoize the summary. 1426 CachedSummaries[ObjCSummaryKey(ID, ClsName, S)] = Summ; 1427 } 1428 1429 return Summ; 1430} 1431 1432void RetainSummaryManager::InitializeClassMethodSummaries() { 1433 assert(ScratchArgs.isEmpty()); 1434 // Create the [NSAssertionHandler currentHander] summary. 1435 addClassMethSummary("NSAssertionHandler", "currentHandler", 1436 getPersistentSummary(RetEffect::MakeNotOwned(RetEffect::ObjC))); 1437 1438 // Create the [NSAutoreleasePool addObject:] summary. 1439 ScratchArgs = AF.add(ScratchArgs, 0, Autorelease); 1440 addClassMethSummary("NSAutoreleasePool", "addObject", 1441 getPersistentSummary(RetEffect::MakeNoRet(), 1442 DoNothing, Autorelease)); 1443 1444 // Create the summaries for [NSObject performSelector...]. We treat 1445 // these as 'stop tracking' for the arguments because they are often 1446 // used for delegates that can release the object. When we have better 1447 // inter-procedural analysis we can potentially do something better. This 1448 // workaround is to remove false positives. 1449 const RetainSummary *Summ = 1450 getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, StopTracking); 1451 IdentifierInfo *NSObjectII = &Ctx.Idents.get("NSObject"); 1452 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1453 "afterDelay", NULL); 1454 addClsMethSummary(NSObjectII, Summ, "performSelector", "withObject", 1455 "afterDelay", "inModes", NULL); 1456 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1457 "withObject", "waitUntilDone", NULL); 1458 addClsMethSummary(NSObjectII, Summ, "performSelectorOnMainThread", 1459 "withObject", "waitUntilDone", "modes", NULL); 1460 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1461 "withObject", "waitUntilDone", NULL); 1462 addClsMethSummary(NSObjectII, Summ, "performSelector", "onThread", 1463 "withObject", "waitUntilDone", "modes", NULL); 1464 addClsMethSummary(NSObjectII, Summ, "performSelectorInBackground", 1465 "withObject", NULL); 1466} 1467 1468void RetainSummaryManager::InitializeMethodSummaries() { 1469 1470 assert (ScratchArgs.isEmpty()); 1471 1472 // Create the "init" selector. It just acts as a pass-through for the 1473 // receiver. 1474 const RetainSummary *InitSumm = getPersistentSummary(ObjCInitRetE, DecRefMsg); 1475 addNSObjectMethSummary(GetNullarySelector("init", Ctx), InitSumm); 1476 1477 // awakeAfterUsingCoder: behaves basically like an 'init' method. It 1478 // claims the receiver and returns a retained object. 1479 addNSObjectMethSummary(GetUnarySelector("awakeAfterUsingCoder", Ctx), 1480 InitSumm); 1481 1482 // The next methods are allocators. 1483 const RetainSummary *AllocSumm = getPersistentSummary(ObjCAllocRetE); 1484 const RetainSummary *CFAllocSumm = 1485 getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF, true)); 1486 1487 // Create the "retain" selector. 1488 RetEffect NoRet = RetEffect::MakeNoRet(); 1489 const RetainSummary *Summ = getPersistentSummary(NoRet, IncRefMsg); 1490 addNSObjectMethSummary(GetNullarySelector("retain", Ctx), Summ); 1491 1492 // Create the "release" selector. 1493 Summ = getPersistentSummary(NoRet, DecRefMsg); 1494 addNSObjectMethSummary(GetNullarySelector("release", Ctx), Summ); 1495 1496 // Create the "drain" selector. 1497 Summ = getPersistentSummary(NoRet, isGCEnabled() ? DoNothing : DecRef); 1498 addNSObjectMethSummary(GetNullarySelector("drain", Ctx), Summ); 1499 1500 // Create the -dealloc summary. 1501 Summ = getPersistentSummary(NoRet, Dealloc); 1502 addNSObjectMethSummary(GetNullarySelector("dealloc", Ctx), Summ); 1503 1504 // Create the "autorelease" selector. 1505 Summ = getPersistentSummary(NoRet, Autorelease); 1506 addNSObjectMethSummary(GetNullarySelector("autorelease", Ctx), Summ); 1507 1508 // Specially handle NSAutoreleasePool. 1509 addInstMethSummary("NSAutoreleasePool", "init", 1510 getPersistentSummary(NoRet, NewAutoreleasePool)); 1511 1512 // For NSWindow, allocated objects are (initially) self-owned. 1513 // FIXME: For now we opt for false negatives with NSWindow, as these objects 1514 // self-own themselves. However, they only do this once they are displayed. 1515 // Thus, we need to track an NSWindow's display status. 1516 // This is tracked in <rdar://problem/6062711>. 1517 // See also http://llvm.org/bugs/show_bug.cgi?id=3714. 1518 const RetainSummary *NoTrackYet = getPersistentSummary(RetEffect::MakeNoRet(), 1519 StopTracking, 1520 StopTracking); 1521 1522 addClassMethSummary("NSWindow", "alloc", NoTrackYet); 1523 1524#if 0 1525 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1526 "styleMask", "backing", "defer", NULL); 1527 1528 addInstMethSummary("NSWindow", NoTrackYet, "initWithContentRect", 1529 "styleMask", "backing", "defer", "screen", NULL); 1530#endif 1531 1532 // For NSPanel (which subclasses NSWindow), allocated objects are not 1533 // self-owned. 1534 // FIXME: For now we don't track NSPanels. object for the same reason 1535 // as for NSWindow objects. 1536 addClassMethSummary("NSPanel", "alloc", NoTrackYet); 1537 1538#if 0 1539 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1540 "styleMask", "backing", "defer", NULL); 1541 1542 addInstMethSummary("NSPanel", NoTrackYet, "initWithContentRect", 1543 "styleMask", "backing", "defer", "screen", NULL); 1544#endif 1545 1546 // Don't track allocated autorelease pools yet, as it is okay to prematurely 1547 // exit a method. 1548 addClassMethSummary("NSAutoreleasePool", "alloc", NoTrackYet); 1549 addClassMethSummary("NSAutoreleasePool", "allocWithZone", NoTrackYet, false); 1550 1551 // Create summaries QCRenderer/QCView -createSnapShotImageOfType: 1552 addInstMethSummary("QCRenderer", AllocSumm, 1553 "createSnapshotImageOfType", NULL); 1554 addInstMethSummary("QCView", AllocSumm, 1555 "createSnapshotImageOfType", NULL); 1556 1557 // Create summaries for CIContext, 'createCGImage' and 1558 // 'createCGLayerWithSize'. These objects are CF objects, and are not 1559 // automatically garbage collected. 1560 addInstMethSummary("CIContext", CFAllocSumm, 1561 "createCGImage", "fromRect", NULL); 1562 addInstMethSummary("CIContext", CFAllocSumm, 1563 "createCGImage", "fromRect", "format", "colorSpace", NULL); 1564 addInstMethSummary("CIContext", CFAllocSumm, "createCGLayerWithSize", 1565 "info", NULL); 1566} 1567 1568//===----------------------------------------------------------------------===// 1569// AutoreleaseBindings - State used to track objects in autorelease pools. 1570//===----------------------------------------------------------------------===// 1571 1572typedef llvm::ImmutableMap<SymbolRef, unsigned> ARCounts; 1573typedef llvm::ImmutableMap<SymbolRef, ARCounts> ARPoolContents; 1574typedef llvm::ImmutableList<SymbolRef> ARStack; 1575 1576static int AutoRCIndex = 0; 1577static int AutoRBIndex = 0; 1578 1579namespace { class AutoreleasePoolContents {}; } 1580namespace { class AutoreleaseStack {}; } 1581 1582namespace clang { 1583namespace ento { 1584template<> struct ProgramStateTrait<AutoreleaseStack> 1585 : public ProgramStatePartialTrait<ARStack> { 1586 static inline void *GDMIndex() { return &AutoRBIndex; } 1587}; 1588 1589template<> struct ProgramStateTrait<AutoreleasePoolContents> 1590 : public ProgramStatePartialTrait<ARPoolContents> { 1591 static inline void *GDMIndex() { return &AutoRCIndex; } 1592}; 1593} // end GR namespace 1594} // end clang namespace 1595 1596static SymbolRef GetCurrentAutoreleasePool(ProgramStateRef state) { 1597 ARStack stack = state->get<AutoreleaseStack>(); 1598 return stack.isEmpty() ? SymbolRef() : stack.getHead(); 1599} 1600 1601static ProgramStateRef 1602SendAutorelease(ProgramStateRef state, 1603 ARCounts::Factory &F, 1604 SymbolRef sym) { 1605 SymbolRef pool = GetCurrentAutoreleasePool(state); 1606 const ARCounts *cnts = state->get<AutoreleasePoolContents>(pool); 1607 ARCounts newCnts(0); 1608 1609 if (cnts) { 1610 const unsigned *cnt = (*cnts).lookup(sym); 1611 newCnts = F.add(*cnts, sym, cnt ? *cnt + 1 : 1); 1612 } 1613 else 1614 newCnts = F.add(F.getEmptyMap(), sym, 1); 1615 1616 return state->set<AutoreleasePoolContents>(pool, newCnts); 1617} 1618 1619//===----------------------------------------------------------------------===// 1620// Error reporting. 1621//===----------------------------------------------------------------------===// 1622namespace { 1623 typedef llvm::DenseMap<const ExplodedNode *, const RetainSummary *> 1624 SummaryLogTy; 1625 1626 //===-------------===// 1627 // Bug Descriptions. // 1628 //===-------------===// 1629 1630 class CFRefBug : public BugType { 1631 protected: 1632 CFRefBug(StringRef name) 1633 : BugType(name, categories::MemoryCoreFoundationObjectiveC) {} 1634 public: 1635 1636 // FIXME: Eventually remove. 1637 virtual const char *getDescription() const = 0; 1638 1639 virtual bool isLeak() const { return false; } 1640 }; 1641 1642 class UseAfterRelease : public CFRefBug { 1643 public: 1644 UseAfterRelease() : CFRefBug("Use-after-release") {} 1645 1646 const char *getDescription() const { 1647 return "Reference-counted object is used after it is released"; 1648 } 1649 }; 1650 1651 class BadRelease : public CFRefBug { 1652 public: 1653 BadRelease() : CFRefBug("Bad release") {} 1654 1655 const char *getDescription() const { 1656 return "Incorrect decrement of the reference count of an object that is " 1657 "not owned at this point by the caller"; 1658 } 1659 }; 1660 1661 class DeallocGC : public CFRefBug { 1662 public: 1663 DeallocGC() 1664 : CFRefBug("-dealloc called while using garbage collection") {} 1665 1666 const char *getDescription() const { 1667 return "-dealloc called while using garbage collection"; 1668 } 1669 }; 1670 1671 class DeallocNotOwned : public CFRefBug { 1672 public: 1673 DeallocNotOwned() 1674 : CFRefBug("-dealloc sent to non-exclusively owned object") {} 1675 1676 const char *getDescription() const { 1677 return "-dealloc sent to object that may be referenced elsewhere"; 1678 } 1679 }; 1680 1681 class OverAutorelease : public CFRefBug { 1682 public: 1683 OverAutorelease() 1684 : CFRefBug("Object sent -autorelease too many times") {} 1685 1686 const char *getDescription() const { 1687 return "Object sent -autorelease too many times"; 1688 } 1689 }; 1690 1691 class ReturnedNotOwnedForOwned : public CFRefBug { 1692 public: 1693 ReturnedNotOwnedForOwned() 1694 : CFRefBug("Method should return an owned object") {} 1695 1696 const char *getDescription() const { 1697 return "Object with a +0 retain count returned to caller where a +1 " 1698 "(owning) retain count is expected"; 1699 } 1700 }; 1701 1702 class Leak : public CFRefBug { 1703 public: 1704 Leak(StringRef name) 1705 : CFRefBug(name) { 1706 // Leaks should not be reported if they are post-dominated by a sink. 1707 setSuppressOnSink(true); 1708 } 1709 1710 const char *getDescription() const { return ""; } 1711 1712 bool isLeak() const { return true; } 1713 }; 1714 1715 //===---------===// 1716 // Bug Reports. // 1717 //===---------===// 1718 1719 class CFRefReportVisitor : public BugReporterVisitorImpl<CFRefReportVisitor> { 1720 protected: 1721 SymbolRef Sym; 1722 const SummaryLogTy &SummaryLog; 1723 bool GCEnabled; 1724 1725 public: 1726 CFRefReportVisitor(SymbolRef sym, bool gcEnabled, const SummaryLogTy &log) 1727 : Sym(sym), SummaryLog(log), GCEnabled(gcEnabled) {} 1728 1729 virtual void Profile(llvm::FoldingSetNodeID &ID) const { 1730 static int x = 0; 1731 ID.AddPointer(&x); 1732 ID.AddPointer(Sym); 1733 } 1734 1735 virtual PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 1736 const ExplodedNode *PrevN, 1737 BugReporterContext &BRC, 1738 BugReport &BR); 1739 1740 virtual PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1741 const ExplodedNode *N, 1742 BugReport &BR); 1743 }; 1744 1745 class CFRefLeakReportVisitor : public CFRefReportVisitor { 1746 public: 1747 CFRefLeakReportVisitor(SymbolRef sym, bool GCEnabled, 1748 const SummaryLogTy &log) 1749 : CFRefReportVisitor(sym, GCEnabled, log) {} 1750 1751 PathDiagnosticPiece *getEndPath(BugReporterContext &BRC, 1752 const ExplodedNode *N, 1753 BugReport &BR); 1754 1755 virtual BugReporterVisitor *clone() const { 1756 // The curiously-recurring template pattern only works for one level of 1757 // subclassing. Rather than make a new template base for 1758 // CFRefReportVisitor, we simply override clone() to do the right thing. 1759 // This could be trouble someday if BugReporterVisitorImpl is ever 1760 // used for something else besides a convenient implementation of clone(). 1761 return new CFRefLeakReportVisitor(*this); 1762 } 1763 }; 1764 1765 class CFRefReport : public BugReport { 1766 void addGCModeDescription(const LangOptions &LOpts, bool GCEnabled); 1767 1768 public: 1769 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1770 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1771 bool registerVisitor = true) 1772 : BugReport(D, D.getDescription(), n) { 1773 if (registerVisitor) 1774 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1775 addGCModeDescription(LOpts, GCEnabled); 1776 } 1777 1778 CFRefReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1779 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1780 StringRef endText) 1781 : BugReport(D, D.getDescription(), endText, n) { 1782 addVisitor(new CFRefReportVisitor(sym, GCEnabled, Log)); 1783 addGCModeDescription(LOpts, GCEnabled); 1784 } 1785 1786 virtual std::pair<ranges_iterator, ranges_iterator> getRanges() { 1787 const CFRefBug& BugTy = static_cast<CFRefBug&>(getBugType()); 1788 if (!BugTy.isLeak()) 1789 return BugReport::getRanges(); 1790 else 1791 return std::make_pair(ranges_iterator(), ranges_iterator()); 1792 } 1793 }; 1794 1795 class CFRefLeakReport : public CFRefReport { 1796 const MemRegion* AllocBinding; 1797 1798 public: 1799 CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, bool GCEnabled, 1800 const SummaryLogTy &Log, ExplodedNode *n, SymbolRef sym, 1801 CheckerContext &Ctx); 1802 1803 PathDiagnosticLocation getLocation(const SourceManager &SM) const { 1804 assert(Location.isValid()); 1805 return Location; 1806 } 1807 }; 1808} // end anonymous namespace 1809 1810void CFRefReport::addGCModeDescription(const LangOptions &LOpts, 1811 bool GCEnabled) { 1812 const char *GCModeDescription = 0; 1813 1814 switch (LOpts.getGC()) { 1815 case LangOptions::GCOnly: 1816 assert(GCEnabled); 1817 GCModeDescription = "Code is compiled to only use garbage collection"; 1818 break; 1819 1820 case LangOptions::NonGC: 1821 assert(!GCEnabled); 1822 GCModeDescription = "Code is compiled to use reference counts"; 1823 break; 1824 1825 case LangOptions::HybridGC: 1826 if (GCEnabled) { 1827 GCModeDescription = "Code is compiled to use either garbage collection " 1828 "(GC) or reference counts (non-GC). The bug occurs " 1829 "with GC enabled"; 1830 break; 1831 } else { 1832 GCModeDescription = "Code is compiled to use either garbage collection " 1833 "(GC) or reference counts (non-GC). The bug occurs " 1834 "in non-GC mode"; 1835 break; 1836 } 1837 } 1838 1839 assert(GCModeDescription && "invalid/unknown GC mode"); 1840 addExtraText(GCModeDescription); 1841} 1842 1843// FIXME: This should be a method on SmallVector. 1844static inline bool contains(const SmallVectorImpl<ArgEffect>& V, 1845 ArgEffect X) { 1846 for (SmallVectorImpl<ArgEffect>::const_iterator I=V.begin(), E=V.end(); 1847 I!=E; ++I) 1848 if (*I == X) return true; 1849 1850 return false; 1851} 1852 1853static bool isNumericLiteralExpression(const Expr *E) { 1854 // FIXME: This set of cases was copied from SemaExprObjC. 1855 return isa<IntegerLiteral>(E) || 1856 isa<CharacterLiteral>(E) || 1857 isa<FloatingLiteral>(E) || 1858 isa<ObjCBoolLiteralExpr>(E) || 1859 isa<CXXBoolLiteralExpr>(E); 1860} 1861 1862static bool isPropertyAccess(const Stmt *S, ParentMap &PM) { 1863 unsigned maxDepth = 4; 1864 while (S && maxDepth) { 1865 if (const PseudoObjectExpr *PO = dyn_cast<PseudoObjectExpr>(S)) { 1866 if (!isa<ObjCMessageExpr>(PO->getSyntacticForm())) 1867 return true; 1868 return false; 1869 } 1870 S = PM.getParent(S); 1871 --maxDepth; 1872 } 1873 return false; 1874} 1875 1876PathDiagnosticPiece *CFRefReportVisitor::VisitNode(const ExplodedNode *N, 1877 const ExplodedNode *PrevN, 1878 BugReporterContext &BRC, 1879 BugReport &BR) { 1880 1881 if (!isa<StmtPoint>(N->getLocation())) 1882 return NULL; 1883 1884 // Check if the type state has changed. 1885 ProgramStateRef PrevSt = PrevN->getState(); 1886 ProgramStateRef CurrSt = N->getState(); 1887 const LocationContext *LCtx = N->getLocationContext(); 1888 1889 const RefVal* CurrT = CurrSt->get<RefBindings>(Sym); 1890 if (!CurrT) return NULL; 1891 1892 const RefVal &CurrV = *CurrT; 1893 const RefVal *PrevT = PrevSt->get<RefBindings>(Sym); 1894 1895 // Create a string buffer to constain all the useful things we want 1896 // to tell the user. 1897 std::string sbuf; 1898 llvm::raw_string_ostream os(sbuf); 1899 1900 // This is the allocation site since the previous node had no bindings 1901 // for this symbol. 1902 if (!PrevT) { 1903 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1904 1905 if (isa<ObjCArrayLiteral>(S)) { 1906 os << "NSArray literal is an object with a +0 retain count"; 1907 } 1908 else if (isa<ObjCDictionaryLiteral>(S)) { 1909 os << "NSDictionary literal is an object with a +0 retain count"; 1910 } 1911 else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) { 1912 if (isNumericLiteralExpression(BL->getSubExpr())) 1913 os << "NSNumber literal is an object with a +0 retain count"; 1914 else { 1915 const ObjCInterfaceDecl *BoxClass = 0; 1916 if (const ObjCMethodDecl *Method = BL->getBoxingMethod()) 1917 BoxClass = Method->getClassInterface(); 1918 1919 // We should always be able to find the boxing class interface, 1920 // but consider this future-proofing. 1921 if (BoxClass) 1922 os << *BoxClass << " b"; 1923 else 1924 os << "B"; 1925 1926 os << "oxed expression produces an object with a +0 retain count"; 1927 } 1928 } 1929 else { 1930 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1931 // Get the name of the callee (if it is available). 1932 SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx); 1933 if (const FunctionDecl *FD = X.getAsFunctionDecl()) 1934 os << "Call to function '" << *FD << '\''; 1935 else 1936 os << "function call"; 1937 } 1938 else { 1939 assert(isa<ObjCMessageExpr>(S)); 1940 // The message expression may have between written directly or as 1941 // a property access. Lazily determine which case we are looking at. 1942 os << (isPropertyAccess(S, N->getParentMap()) ? "Property" : "Method"); 1943 } 1944 1945 if (CurrV.getObjKind() == RetEffect::CF) { 1946 os << " returns a Core Foundation object with a "; 1947 } 1948 else { 1949 assert (CurrV.getObjKind() == RetEffect::ObjC); 1950 os << " returns an Objective-C object with a "; 1951 } 1952 1953 if (CurrV.isOwned()) { 1954 os << "+1 retain count"; 1955 1956 if (GCEnabled) { 1957 assert(CurrV.getObjKind() == RetEffect::CF); 1958 os << ". " 1959 "Core Foundation objects are not automatically garbage collected."; 1960 } 1961 } 1962 else { 1963 assert (CurrV.isNotOwned()); 1964 os << "+0 retain count"; 1965 } 1966 } 1967 1968 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 1969 N->getLocationContext()); 1970 return new PathDiagnosticEventPiece(Pos, os.str()); 1971 } 1972 1973 // Gather up the effects that were performed on the object at this 1974 // program point 1975 SmallVector<ArgEffect, 2> AEffects; 1976 1977 const ExplodedNode *OrigNode = BRC.getNodeResolver().getOriginalNode(N); 1978 if (const RetainSummary *Summ = SummaryLog.lookup(OrigNode)) { 1979 // We only have summaries attached to nodes after evaluating CallExpr and 1980 // ObjCMessageExprs. 1981 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 1982 1983 if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { 1984 // Iterate through the parameter expressions and see if the symbol 1985 // was ever passed as an argument. 1986 unsigned i = 0; 1987 1988 for (CallExpr::const_arg_iterator AI=CE->arg_begin(), AE=CE->arg_end(); 1989 AI!=AE; ++AI, ++i) { 1990 1991 // Retrieve the value of the argument. Is it the symbol 1992 // we are interested in? 1993 if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym) 1994 continue; 1995 1996 // We have an argument. Get the effect! 1997 AEffects.push_back(Summ->getArg(i)); 1998 } 1999 } 2000 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) { 2001 if (const Expr *receiver = ME->getInstanceReceiver()) 2002 if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx) 2003 .getAsLocSymbol() == Sym) { 2004 // The symbol we are tracking is the receiver. 2005 AEffects.push_back(Summ->getReceiverEffect()); 2006 } 2007 } 2008 } 2009 2010 do { 2011 // Get the previous type state. 2012 RefVal PrevV = *PrevT; 2013 2014 // Specially handle -dealloc. 2015 if (!GCEnabled && contains(AEffects, Dealloc)) { 2016 // Determine if the object's reference count was pushed to zero. 2017 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2018 // We may not have transitioned to 'release' if we hit an error. 2019 // This case is handled elsewhere. 2020 if (CurrV.getKind() == RefVal::Released) { 2021 assert(CurrV.getCombinedCounts() == 0); 2022 os << "Object released by directly sending the '-dealloc' message"; 2023 break; 2024 } 2025 } 2026 2027 // Specially handle CFMakeCollectable and friends. 2028 if (contains(AEffects, MakeCollectable)) { 2029 // Get the name of the function. 2030 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2031 SVal X = 2032 CurrSt->getSValAsScalarOrLoc(cast<CallExpr>(S)->getCallee(), LCtx); 2033 const FunctionDecl *FD = X.getAsFunctionDecl(); 2034 2035 if (GCEnabled) { 2036 // Determine if the object's reference count was pushed to zero. 2037 assert(!(PrevV == CurrV) && "The typestate *must* have changed."); 2038 2039 os << "In GC mode a call to '" << *FD 2040 << "' decrements an object's retain count and registers the " 2041 "object with the garbage collector. "; 2042 2043 if (CurrV.getKind() == RefVal::Released) { 2044 assert(CurrV.getCount() == 0); 2045 os << "Since it now has a 0 retain count the object can be " 2046 "automatically collected by the garbage collector."; 2047 } 2048 else 2049 os << "An object must have a 0 retain count to be garbage collected. " 2050 "After this call its retain count is +" << CurrV.getCount() 2051 << '.'; 2052 } 2053 else 2054 os << "When GC is not enabled a call to '" << *FD 2055 << "' has no effect on its argument."; 2056 2057 // Nothing more to say. 2058 break; 2059 } 2060 2061 // Determine if the typestate has changed. 2062 if (!(PrevV == CurrV)) 2063 switch (CurrV.getKind()) { 2064 case RefVal::Owned: 2065 case RefVal::NotOwned: 2066 2067 if (PrevV.getCount() == CurrV.getCount()) { 2068 // Did an autorelease message get sent? 2069 if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount()) 2070 return 0; 2071 2072 assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount()); 2073 os << "Object sent -autorelease message"; 2074 break; 2075 } 2076 2077 if (PrevV.getCount() > CurrV.getCount()) 2078 os << "Reference count decremented."; 2079 else 2080 os << "Reference count incremented."; 2081 2082 if (unsigned Count = CurrV.getCount()) 2083 os << " The object now has a +" << Count << " retain count."; 2084 2085 if (PrevV.getKind() == RefVal::Released) { 2086 assert(GCEnabled && CurrV.getCount() > 0); 2087 os << " The object is not eligible for garbage collection until " 2088 "the retain count reaches 0 again."; 2089 } 2090 2091 break; 2092 2093 case RefVal::Released: 2094 os << "Object released."; 2095 break; 2096 2097 case RefVal::ReturnedOwned: 2098 // Autoreleases can be applied after marking a node ReturnedOwned. 2099 if (CurrV.getAutoreleaseCount()) 2100 return NULL; 2101 2102 os << "Object returned to caller as an owning reference (single " 2103 "retain count transferred to caller)"; 2104 break; 2105 2106 case RefVal::ReturnedNotOwned: 2107 os << "Object returned to caller with a +0 retain count"; 2108 break; 2109 2110 default: 2111 return NULL; 2112 } 2113 2114 // Emit any remaining diagnostics for the argument effects (if any). 2115 for (SmallVectorImpl<ArgEffect>::iterator I=AEffects.begin(), 2116 E=AEffects.end(); I != E; ++I) { 2117 2118 // A bunch of things have alternate behavior under GC. 2119 if (GCEnabled) 2120 switch (*I) { 2121 default: break; 2122 case Autorelease: 2123 os << "In GC mode an 'autorelease' has no effect."; 2124 continue; 2125 case IncRefMsg: 2126 os << "In GC mode the 'retain' message has no effect."; 2127 continue; 2128 case DecRefMsg: 2129 os << "In GC mode the 'release' message has no effect."; 2130 continue; 2131 } 2132 } 2133 } while (0); 2134 2135 if (os.str().empty()) 2136 return 0; // We have nothing to say! 2137 2138 const Stmt *S = cast<StmtPoint>(N->getLocation()).getStmt(); 2139 PathDiagnosticLocation Pos(S, BRC.getSourceManager(), 2140 N->getLocationContext()); 2141 PathDiagnosticPiece *P = new PathDiagnosticEventPiece(Pos, os.str()); 2142 2143 // Add the range by scanning the children of the statement for any bindings 2144 // to Sym. 2145 for (Stmt::const_child_iterator I = S->child_begin(), E = S->child_end(); 2146 I!=E; ++I) 2147 if (const Expr *Exp = dyn_cast_or_null<Expr>(*I)) 2148 if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) { 2149 P->addRange(Exp->getSourceRange()); 2150 break; 2151 } 2152 2153 return P; 2154} 2155 2156// Find the first node in the current function context that referred to the 2157// tracked symbol and the memory location that value was stored to. Note, the 2158// value is only reported if the allocation occurred in the same function as 2159// the leak. 2160static std::pair<const ExplodedNode*,const MemRegion*> 2161GetAllocationSite(ProgramStateManager& StateMgr, const ExplodedNode *N, 2162 SymbolRef Sym) { 2163 const ExplodedNode *Last = N; 2164 const MemRegion* FirstBinding = 0; 2165 const LocationContext *LeakContext = N->getLocationContext(); 2166 2167 while (N) { 2168 ProgramStateRef St = N->getState(); 2169 RefBindings B = St->get<RefBindings>(); 2170 2171 if (!B.lookup(Sym)) 2172 break; 2173 2174 StoreManager::FindUniqueBinding FB(Sym); 2175 StateMgr.iterBindings(St, FB); 2176 if (FB) FirstBinding = FB.getRegion(); 2177 2178 // Allocation node, is the last node in the current context in which the 2179 // symbol was tracked. 2180 if (N->getLocationContext() == LeakContext) 2181 Last = N; 2182 2183 N = N->pred_empty() ? NULL : *(N->pred_begin()); 2184 } 2185 2186 // If allocation happened in a function different from the leak node context, 2187 // do not report the binding. 2188 if (N->getLocationContext() != LeakContext) { 2189 FirstBinding = 0; 2190 } 2191 2192 return std::make_pair(Last, FirstBinding); 2193} 2194 2195PathDiagnosticPiece* 2196CFRefReportVisitor::getEndPath(BugReporterContext &BRC, 2197 const ExplodedNode *EndN, 2198 BugReport &BR) { 2199 BR.markInteresting(Sym); 2200 return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR); 2201} 2202 2203PathDiagnosticPiece* 2204CFRefLeakReportVisitor::getEndPath(BugReporterContext &BRC, 2205 const ExplodedNode *EndN, 2206 BugReport &BR) { 2207 2208 // Tell the BugReporterContext to report cases when the tracked symbol is 2209 // assigned to different variables, etc. 2210 BR.markInteresting(Sym); 2211 2212 // We are reporting a leak. Walk up the graph to get to the first node where 2213 // the symbol appeared, and also get the first VarDecl that tracked object 2214 // is stored to. 2215 const ExplodedNode *AllocNode = 0; 2216 const MemRegion* FirstBinding = 0; 2217 2218 llvm::tie(AllocNode, FirstBinding) = 2219 GetAllocationSite(BRC.getStateManager(), EndN, Sym); 2220 2221 SourceManager& SM = BRC.getSourceManager(); 2222 2223 // Compute an actual location for the leak. Sometimes a leak doesn't 2224 // occur at an actual statement (e.g., transition between blocks; end 2225 // of function) so we need to walk the graph and compute a real location. 2226 const ExplodedNode *LeakN = EndN; 2227 PathDiagnosticLocation L = PathDiagnosticLocation::createEndOfPath(LeakN, SM); 2228 2229 std::string sbuf; 2230 llvm::raw_string_ostream os(sbuf); 2231 2232 os << "Object leaked: "; 2233 2234 if (FirstBinding) { 2235 os << "object allocated and stored into '" 2236 << FirstBinding->getString() << '\''; 2237 } 2238 else 2239 os << "allocated object"; 2240 2241 // Get the retain count. 2242 const RefVal* RV = EndN->getState()->get<RefBindings>(Sym); 2243 2244 if (RV->getKind() == RefVal::ErrorLeakReturned) { 2245 // FIXME: Per comments in rdar://6320065, "create" only applies to CF 2246 // objects. Only "copy", "alloc", "retain" and "new" transfer ownership 2247 // to the caller for NS objects. 2248 const Decl *D = &EndN->getCodeDecl(); 2249 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2250 os << " is returned from a method whose name ('" 2251 << MD->getSelector().getAsString() 2252 << "') does not start with 'copy', 'mutableCopy', 'alloc' or 'new'." 2253 " This violates the naming convention rules" 2254 " given in the Memory Management Guide for Cocoa"; 2255 } 2256 else { 2257 const FunctionDecl *FD = cast<FunctionDecl>(D); 2258 os << " is returned from a function whose name ('" 2259 << *FD 2260 << "') does not contain 'Copy' or 'Create'. This violates the naming" 2261 " convention rules given in the Memory Management Guide for Core" 2262 " Foundation"; 2263 } 2264 } 2265 else if (RV->getKind() == RefVal::ErrorGCLeakReturned) { 2266 ObjCMethodDecl &MD = cast<ObjCMethodDecl>(EndN->getCodeDecl()); 2267 os << " and returned from method '" << MD.getSelector().getAsString() 2268 << "' is potentially leaked when using garbage collection. Callers " 2269 "of this method do not expect a returned object with a +1 retain " 2270 "count since they expect the object to be managed by the garbage " 2271 "collector"; 2272 } 2273 else 2274 os << " is not referenced later in this execution path and has a retain " 2275 "count of +" << RV->getCount(); 2276 2277 return new PathDiagnosticEventPiece(L, os.str()); 2278} 2279 2280CFRefLeakReport::CFRefLeakReport(CFRefBug &D, const LangOptions &LOpts, 2281 bool GCEnabled, const SummaryLogTy &Log, 2282 ExplodedNode *n, SymbolRef sym, 2283 CheckerContext &Ctx) 2284: CFRefReport(D, LOpts, GCEnabled, Log, n, sym, false) { 2285 2286 // Most bug reports are cached at the location where they occurred. 2287 // With leaks, we want to unique them by the location where they were 2288 // allocated, and only report a single path. To do this, we need to find 2289 // the allocation site of a piece of tracked memory, which we do via a 2290 // call to GetAllocationSite. This will walk the ExplodedGraph backwards. 2291 // Note that this is *not* the trimmed graph; we are guaranteed, however, 2292 // that all ancestor nodes that represent the allocation site have the 2293 // same SourceLocation. 2294 const ExplodedNode *AllocNode = 0; 2295 2296 const SourceManager& SMgr = Ctx.getSourceManager(); 2297 2298 llvm::tie(AllocNode, AllocBinding) = // Set AllocBinding. 2299 GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym); 2300 2301 // Get the SourceLocation for the allocation site. 2302 ProgramPoint P = AllocNode->getLocation(); 2303 const Stmt *AllocStmt = cast<PostStmt>(P).getStmt(); 2304 Location = PathDiagnosticLocation::createBegin(AllocStmt, SMgr, 2305 n->getLocationContext()); 2306 // Fill in the description of the bug. 2307 Description.clear(); 2308 llvm::raw_string_ostream os(Description); 2309 os << "Potential leak "; 2310 if (GCEnabled) 2311 os << "(when using garbage collection) "; 2312 os << "of an object"; 2313 2314 // FIXME: AllocBinding doesn't get populated for RegionStore yet. 2315 if (AllocBinding) 2316 os << " stored into '" << AllocBinding->getString() << '\''; 2317 2318 addVisitor(new CFRefLeakReportVisitor(sym, GCEnabled, Log)); 2319} 2320 2321//===----------------------------------------------------------------------===// 2322// Main checker logic. 2323//===----------------------------------------------------------------------===// 2324 2325namespace { 2326class RetainCountChecker 2327 : public Checker< check::Bind, 2328 check::DeadSymbols, 2329 check::EndAnalysis, 2330 check::EndPath, 2331 check::PostStmt<BlockExpr>, 2332 check::PostStmt<CastExpr>, 2333 check::PostStmt<CallExpr>, 2334 check::PostStmt<CXXConstructExpr>, 2335 check::PostStmt<ObjCArrayLiteral>, 2336 check::PostStmt<ObjCDictionaryLiteral>, 2337 check::PostStmt<ObjCBoxedExpr>, 2338 check::PostObjCMessage, 2339 check::PreStmt<ReturnStmt>, 2340 check::RegionChanges, 2341 eval::Assume, 2342 eval::Call > { 2343 mutable OwningPtr<CFRefBug> useAfterRelease, releaseNotOwned; 2344 mutable OwningPtr<CFRefBug> deallocGC, deallocNotOwned; 2345 mutable OwningPtr<CFRefBug> overAutorelease, returnNotOwnedForOwned; 2346 mutable OwningPtr<CFRefBug> leakWithinFunction, leakAtReturn; 2347 mutable OwningPtr<CFRefBug> leakWithinFunctionGC, leakAtReturnGC; 2348 2349 typedef llvm::DenseMap<SymbolRef, const SimpleProgramPointTag *> SymbolTagMap; 2350 2351 // This map is only used to ensure proper deletion of any allocated tags. 2352 mutable SymbolTagMap DeadSymbolTags; 2353 2354 mutable OwningPtr<RetainSummaryManager> Summaries; 2355 mutable OwningPtr<RetainSummaryManager> SummariesGC; 2356 2357 mutable ARCounts::Factory ARCountFactory; 2358 2359 mutable SummaryLogTy SummaryLog; 2360 mutable bool ShouldResetSummaryLog; 2361 2362public: 2363 RetainCountChecker() : ShouldResetSummaryLog(false) {} 2364 2365 virtual ~RetainCountChecker() { 2366 DeleteContainerSeconds(DeadSymbolTags); 2367 } 2368 2369 void checkEndAnalysis(ExplodedGraph &G, BugReporter &BR, 2370 ExprEngine &Eng) const { 2371 // FIXME: This is a hack to make sure the summary log gets cleared between 2372 // analyses of different code bodies. 2373 // 2374 // Why is this necessary? Because a checker's lifetime is tied to a 2375 // translation unit, but an ExplodedGraph's lifetime is just a code body. 2376 // Once in a blue moon, a new ExplodedNode will have the same address as an 2377 // old one with an associated summary, and the bug report visitor gets very 2378 // confused. (To make things worse, the summary lifetime is currently also 2379 // tied to a code body, so we get a crash instead of incorrect results.) 2380 // 2381 // Why is this a bad solution? Because if the lifetime of the ExplodedGraph 2382 // changes, things will start going wrong again. Really the lifetime of this 2383 // log needs to be tied to either the specific nodes in it or the entire 2384 // ExplodedGraph, not to a specific part of the code being analyzed. 2385 // 2386 // (Also, having stateful local data means that the same checker can't be 2387 // used from multiple threads, but a lot of checkers have incorrect 2388 // assumptions about that anyway. So that wasn't a priority at the time of 2389 // this fix.) 2390 // 2391 // This happens at the end of analysis, but bug reports are emitted /after/ 2392 // this point. So we can't just clear the summary log now. Instead, we mark 2393 // that the next time we access the summary log, it should be cleared. 2394 2395 // If we never reset the summary log during /this/ code body analysis, 2396 // there were no new summaries. There might still have been summaries from 2397 // the /last/ analysis, so clear them out to make sure the bug report 2398 // visitors don't get confused. 2399 if (ShouldResetSummaryLog) 2400 SummaryLog.clear(); 2401 2402 ShouldResetSummaryLog = !SummaryLog.empty(); 2403 } 2404 2405 CFRefBug *getLeakWithinFunctionBug(const LangOptions &LOpts, 2406 bool GCEnabled) const { 2407 if (GCEnabled) { 2408 if (!leakWithinFunctionGC) 2409 leakWithinFunctionGC.reset(new Leak("Leak of object when using " 2410 "garbage collection")); 2411 return leakWithinFunctionGC.get(); 2412 } else { 2413 if (!leakWithinFunction) { 2414 if (LOpts.getGC() == LangOptions::HybridGC) { 2415 leakWithinFunction.reset(new Leak("Leak of object when not using " 2416 "garbage collection (GC) in " 2417 "dual GC/non-GC code")); 2418 } else { 2419 leakWithinFunction.reset(new Leak("Leak")); 2420 } 2421 } 2422 return leakWithinFunction.get(); 2423 } 2424 } 2425 2426 CFRefBug *getLeakAtReturnBug(const LangOptions &LOpts, bool GCEnabled) const { 2427 if (GCEnabled) { 2428 if (!leakAtReturnGC) 2429 leakAtReturnGC.reset(new Leak("Leak of returned object when using " 2430 "garbage collection")); 2431 return leakAtReturnGC.get(); 2432 } else { 2433 if (!leakAtReturn) { 2434 if (LOpts.getGC() == LangOptions::HybridGC) { 2435 leakAtReturn.reset(new Leak("Leak of returned object when not using " 2436 "garbage collection (GC) in dual " 2437 "GC/non-GC code")); 2438 } else { 2439 leakAtReturn.reset(new Leak("Leak of returned object")); 2440 } 2441 } 2442 return leakAtReturn.get(); 2443 } 2444 } 2445 2446 RetainSummaryManager &getSummaryManager(ASTContext &Ctx, 2447 bool GCEnabled) const { 2448 // FIXME: We don't support ARC being turned on and off during one analysis. 2449 // (nor, for that matter, do we support changing ASTContexts) 2450 bool ARCEnabled = (bool)Ctx.getLangOpts().ObjCAutoRefCount; 2451 if (GCEnabled) { 2452 if (!SummariesGC) 2453 SummariesGC.reset(new RetainSummaryManager(Ctx, true, ARCEnabled)); 2454 else 2455 assert(SummariesGC->isARCEnabled() == ARCEnabled); 2456 return *SummariesGC; 2457 } else { 2458 if (!Summaries) 2459 Summaries.reset(new RetainSummaryManager(Ctx, false, ARCEnabled)); 2460 else 2461 assert(Summaries->isARCEnabled() == ARCEnabled); 2462 return *Summaries; 2463 } 2464 } 2465 2466 RetainSummaryManager &getSummaryManager(CheckerContext &C) const { 2467 return getSummaryManager(C.getASTContext(), C.isObjCGCEnabled()); 2468 } 2469 2470 void printState(raw_ostream &Out, ProgramStateRef State, 2471 const char *NL, const char *Sep) const; 2472 2473 void checkBind(SVal loc, SVal val, const Stmt *S, CheckerContext &C) const; 2474 void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; 2475 void checkPostStmt(const CastExpr *CE, CheckerContext &C) const; 2476 2477 void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; 2478 void checkPostStmt(const CXXConstructExpr *CE, CheckerContext &C) const; 2479 void checkPostStmt(const ObjCArrayLiteral *AL, CheckerContext &C) const; 2480 void checkPostStmt(const ObjCDictionaryLiteral *DL, CheckerContext &C) const; 2481 void checkPostStmt(const ObjCBoxedExpr *BE, CheckerContext &C) const; 2482 2483 void checkPostObjCMessage(const ObjCMessage &Msg, CheckerContext &C) const; 2484 2485 void checkSummary(const RetainSummary &Summ, const CallOrObjCMessage &Call, 2486 CheckerContext &C) const; 2487 2488 bool evalCall(const CallExpr *CE, CheckerContext &C) const; 2489 2490 ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, 2491 bool Assumption) const; 2492 2493 ProgramStateRef 2494 checkRegionChanges(ProgramStateRef state, 2495 const StoreManager::InvalidatedSymbols *invalidated, 2496 ArrayRef<const MemRegion *> ExplicitRegions, 2497 ArrayRef<const MemRegion *> Regions, 2498 const CallOrObjCMessage *Call) const; 2499 2500 bool wantsRegionChangeUpdate(ProgramStateRef state) const { 2501 return true; 2502 } 2503 2504 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 2505 void checkReturnWithRetEffect(const ReturnStmt *S, CheckerContext &C, 2506 ExplodedNode *Pred, RetEffect RE, RefVal X, 2507 SymbolRef Sym, ProgramStateRef state) const; 2508 2509 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; 2510 void checkEndPath(CheckerContext &C) const; 2511 2512 ProgramStateRef updateSymbol(ProgramStateRef state, SymbolRef sym, 2513 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2514 CheckerContext &C) const; 2515 2516 void processNonLeakError(ProgramStateRef St, SourceRange ErrorRange, 2517 RefVal::Kind ErrorKind, SymbolRef Sym, 2518 CheckerContext &C) const; 2519 2520 void processObjCLiterals(CheckerContext &C, const Expr *Ex) const; 2521 2522 const ProgramPointTag *getDeadSymbolTag(SymbolRef sym) const; 2523 2524 ProgramStateRef handleSymbolDeath(ProgramStateRef state, 2525 SymbolRef sid, RefVal V, 2526 SmallVectorImpl<SymbolRef> &Leaked) const; 2527 2528 std::pair<ExplodedNode *, ProgramStateRef > 2529 handleAutoreleaseCounts(ProgramStateRef state, 2530 GenericNodeBuilderRefCount Bd, ExplodedNode *Pred, 2531 CheckerContext &Ctx, SymbolRef Sym, RefVal V) const; 2532 2533 ExplodedNode *processLeaks(ProgramStateRef state, 2534 SmallVectorImpl<SymbolRef> &Leaked, 2535 GenericNodeBuilderRefCount &Builder, 2536 CheckerContext &Ctx, 2537 ExplodedNode *Pred = 0) const; 2538}; 2539} // end anonymous namespace 2540 2541namespace { 2542class StopTrackingCallback : public SymbolVisitor { 2543 ProgramStateRef state; 2544public: 2545 StopTrackingCallback(ProgramStateRef st) : state(st) {} 2546 ProgramStateRef getState() const { return state; } 2547 2548 bool VisitSymbol(SymbolRef sym) { 2549 state = state->remove<RefBindings>(sym); 2550 return true; 2551 } 2552}; 2553} // end anonymous namespace 2554 2555//===----------------------------------------------------------------------===// 2556// Handle statements that may have an effect on refcounts. 2557//===----------------------------------------------------------------------===// 2558 2559void RetainCountChecker::checkPostStmt(const BlockExpr *BE, 2560 CheckerContext &C) const { 2561 2562 // Scan the BlockDecRefExprs for any object the retain count checker 2563 // may be tracking. 2564 if (!BE->getBlockDecl()->hasCaptures()) 2565 return; 2566 2567 ProgramStateRef state = C.getState(); 2568 const BlockDataRegion *R = 2569 cast<BlockDataRegion>(state->getSVal(BE, 2570 C.getLocationContext()).getAsRegion()); 2571 2572 BlockDataRegion::referenced_vars_iterator I = R->referenced_vars_begin(), 2573 E = R->referenced_vars_end(); 2574 2575 if (I == E) 2576 return; 2577 2578 // FIXME: For now we invalidate the tracking of all symbols passed to blocks 2579 // via captured variables, even though captured variables result in a copy 2580 // and in implicit increment/decrement of a retain count. 2581 SmallVector<const MemRegion*, 10> Regions; 2582 const LocationContext *LC = C.getLocationContext(); 2583 MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); 2584 2585 for ( ; I != E; ++I) { 2586 const VarRegion *VR = *I; 2587 if (VR->getSuperRegion() == R) { 2588 VR = MemMgr.getVarRegion(VR->getDecl(), LC); 2589 } 2590 Regions.push_back(VR); 2591 } 2592 2593 state = 2594 state->scanReachableSymbols<StopTrackingCallback>(Regions.data(), 2595 Regions.data() + Regions.size()).getState(); 2596 C.addTransition(state); 2597} 2598 2599void RetainCountChecker::checkPostStmt(const CastExpr *CE, 2600 CheckerContext &C) const { 2601 const ObjCBridgedCastExpr *BE = dyn_cast<ObjCBridgedCastExpr>(CE); 2602 if (!BE) 2603 return; 2604 2605 ArgEffect AE = IncRef; 2606 2607 switch (BE->getBridgeKind()) { 2608 case clang::OBC_Bridge: 2609 // Do nothing. 2610 return; 2611 case clang::OBC_BridgeRetained: 2612 AE = IncRef; 2613 break; 2614 case clang::OBC_BridgeTransfer: 2615 AE = DecRefBridgedTransfered; 2616 break; 2617 } 2618 2619 ProgramStateRef state = C.getState(); 2620 SymbolRef Sym = state->getSVal(CE, C.getLocationContext()).getAsLocSymbol(); 2621 if (!Sym) 2622 return; 2623 const RefVal* T = state->get<RefBindings>(Sym); 2624 if (!T) 2625 return; 2626 2627 RefVal::Kind hasErr = (RefVal::Kind) 0; 2628 state = updateSymbol(state, Sym, *T, AE, hasErr, C); 2629 2630 if (hasErr) { 2631 // FIXME: If we get an error during a bridge cast, should we report it? 2632 // Should we assert that there is no error? 2633 return; 2634 } 2635 2636 C.addTransition(state); 2637} 2638 2639void RetainCountChecker::checkPostStmt(const CallExpr *CE, 2640 CheckerContext &C) const { 2641 if (C.wasInlined) 2642 return; 2643 2644 // Get the callee. 2645 ProgramStateRef state = C.getState(); 2646 const Expr *Callee = CE->getCallee(); 2647 SVal L = state->getSVal(Callee, C.getLocationContext()); 2648 2649 RetainSummaryManager &Summaries = getSummaryManager(C); 2650 const RetainSummary *Summ = 0; 2651 2652 // FIXME: Better support for blocks. For now we stop tracking anything 2653 // that is passed to blocks. 2654 // FIXME: Need to handle variables that are "captured" by the block. 2655 if (dyn_cast_or_null<BlockDataRegion>(L.getAsRegion())) { 2656 Summ = Summaries.getPersistentStopSummary(); 2657 } else if (const FunctionDecl *FD = L.getAsFunctionDecl()) { 2658 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2659 Summ = Summaries.getSummary(FD, &CME); 2660 } else if (const CXXMemberCallExpr *me = dyn_cast<CXXMemberCallExpr>(CE)) { 2661 if (const CXXMethodDecl *MD = me->getMethodDecl()) { 2662 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2663 Summ = Summaries.getSummary(MD, &CME); 2664 } 2665 } 2666 2667 if (!Summ) 2668 Summ = Summaries.getDefaultSummary(); 2669 2670 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2671} 2672 2673void RetainCountChecker::checkPostStmt(const CXXConstructExpr *CE, 2674 CheckerContext &C) const { 2675 const CXXConstructorDecl *Ctor = CE->getConstructor(); 2676 if (!Ctor) 2677 return; 2678 2679 RetainSummaryManager &Summaries = getSummaryManager(C); 2680 ProgramStateRef state = C.getState(); 2681 CallOrObjCMessage CME(CE, state, C.getLocationContext()); 2682 const RetainSummary *Summ = Summaries.getSummary(Ctor, &CME); 2683 2684 // If we didn't get a summary, this constructor doesn't affect retain counts. 2685 if (!Summ) 2686 return; 2687 2688 checkSummary(*Summ, CallOrObjCMessage(CE, state, C.getLocationContext()), C); 2689} 2690 2691void RetainCountChecker::processObjCLiterals(CheckerContext &C, 2692 const Expr *Ex) const { 2693 ProgramStateRef state = C.getState(); 2694 const ExplodedNode *pred = C.getPredecessor(); 2695 for (Stmt::const_child_iterator it = Ex->child_begin(), et = Ex->child_end() ; 2696 it != et ; ++it) { 2697 const Stmt *child = *it; 2698 SVal V = state->getSVal(child, pred->getLocationContext()); 2699 if (SymbolRef sym = V.getAsSymbol()) 2700 if (const RefVal* T = state->get<RefBindings>(sym)) { 2701 RefVal::Kind hasErr = (RefVal::Kind) 0; 2702 state = updateSymbol(state, sym, *T, MayEscape, hasErr, C); 2703 if (hasErr) { 2704 processNonLeakError(state, child->getSourceRange(), hasErr, sym, C); 2705 return; 2706 } 2707 } 2708 } 2709 2710 // Return the object as autoreleased. 2711 // RetEffect RE = RetEffect::MakeNotOwned(RetEffect::ObjC); 2712 if (SymbolRef sym = 2713 state->getSVal(Ex, pred->getLocationContext()).getAsSymbol()) { 2714 QualType ResultTy = Ex->getType(); 2715 state = state->set<RefBindings>(sym, RefVal::makeNotOwned(RetEffect::ObjC, 2716 ResultTy)); 2717 } 2718 2719 C.addTransition(state); 2720} 2721 2722void RetainCountChecker::checkPostStmt(const ObjCArrayLiteral *AL, 2723 CheckerContext &C) const { 2724 // Apply the 'MayEscape' to all values. 2725 processObjCLiterals(C, AL); 2726} 2727 2728void RetainCountChecker::checkPostStmt(const ObjCDictionaryLiteral *DL, 2729 CheckerContext &C) const { 2730 // Apply the 'MayEscape' to all keys and values. 2731 processObjCLiterals(C, DL); 2732} 2733 2734void RetainCountChecker::checkPostStmt(const ObjCBoxedExpr *Ex, 2735 CheckerContext &C) const { 2736 const ExplodedNode *Pred = C.getPredecessor(); 2737 const LocationContext *LCtx = Pred->getLocationContext(); 2738 ProgramStateRef State = Pred->getState(); 2739 2740 if (SymbolRef Sym = State->getSVal(Ex, LCtx).getAsSymbol()) { 2741 QualType ResultTy = Ex->getType(); 2742 State = State->set<RefBindings>(Sym, RefVal::makeNotOwned(RetEffect::ObjC, 2743 ResultTy)); 2744 } 2745 2746 C.addTransition(State); 2747} 2748 2749void RetainCountChecker::checkPostObjCMessage(const ObjCMessage &Msg, 2750 CheckerContext &C) const { 2751 ProgramStateRef state = C.getState(); 2752 2753 RetainSummaryManager &Summaries = getSummaryManager(C); 2754 2755 const RetainSummary *Summ; 2756 if (Msg.isInstanceMessage()) { 2757 const LocationContext *LC = C.getLocationContext(); 2758 Summ = Summaries.getInstanceMethodSummary(Msg, state, LC); 2759 } else { 2760 Summ = Summaries.getClassMethodSummary(Msg); 2761 } 2762 2763 // If we didn't get a summary, this message doesn't affect retain counts. 2764 if (!Summ) 2765 return; 2766 2767 checkSummary(*Summ, CallOrObjCMessage(Msg, state, C.getLocationContext()), C); 2768} 2769 2770/// GetReturnType - Used to get the return type of a message expression or 2771/// function call with the intention of affixing that type to a tracked symbol. 2772/// While the the return type can be queried directly from RetEx, when 2773/// invoking class methods we augment to the return type to be that of 2774/// a pointer to the class (as opposed it just being id). 2775// FIXME: We may be able to do this with related result types instead. 2776// This function is probably overestimating. 2777static QualType GetReturnType(const Expr *RetE, ASTContext &Ctx) { 2778 QualType RetTy = RetE->getType(); 2779 // If RetE is not a message expression just return its type. 2780 // If RetE is a message expression, return its types if it is something 2781 /// more specific than id. 2782 if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(RetE)) 2783 if (const ObjCObjectPointerType *PT = RetTy->getAs<ObjCObjectPointerType>()) 2784 if (PT->isObjCQualifiedIdType() || PT->isObjCIdType() || 2785 PT->isObjCClassType()) { 2786 // At this point we know the return type of the message expression is 2787 // id, id<...>, or Class. If we have an ObjCInterfaceDecl, we know this 2788 // is a call to a class method whose type we can resolve. In such 2789 // cases, promote the return type to XXX* (where XXX is the class). 2790 const ObjCInterfaceDecl *D = ME->getReceiverInterface(); 2791 return !D ? RetTy : 2792 Ctx.getObjCObjectPointerType(Ctx.getObjCInterfaceType(D)); 2793 } 2794 2795 return RetTy; 2796} 2797 2798void RetainCountChecker::checkSummary(const RetainSummary &Summ, 2799 const CallOrObjCMessage &CallOrMsg, 2800 CheckerContext &C) const { 2801 ProgramStateRef state = C.getState(); 2802 2803 // Evaluate the effect of the arguments. 2804 RefVal::Kind hasErr = (RefVal::Kind) 0; 2805 SourceRange ErrorRange; 2806 SymbolRef ErrorSym = 0; 2807 2808 for (unsigned idx = 0, e = CallOrMsg.getNumArgs(); idx != e; ++idx) { 2809 SVal V = CallOrMsg.getArgSVal(idx); 2810 2811 if (SymbolRef Sym = V.getAsLocSymbol()) { 2812 if (RefBindings::data_type *T = state->get<RefBindings>(Sym)) { 2813 state = updateSymbol(state, Sym, *T, Summ.getArg(idx), hasErr, C); 2814 if (hasErr) { 2815 ErrorRange = CallOrMsg.getArgSourceRange(idx); 2816 ErrorSym = Sym; 2817 break; 2818 } 2819 } 2820 } 2821 } 2822 2823 // Evaluate the effect on the message receiver. 2824 bool ReceiverIsTracked = false; 2825 if (!hasErr && CallOrMsg.isObjCMessage()) { 2826 const LocationContext *LC = C.getLocationContext(); 2827 SVal Receiver = CallOrMsg.getInstanceMessageReceiver(LC); 2828 if (SymbolRef Sym = Receiver.getAsLocSymbol()) { 2829 if (const RefVal *T = state->get<RefBindings>(Sym)) { 2830 ReceiverIsTracked = true; 2831 state = updateSymbol(state, Sym, *T, Summ.getReceiverEffect(), 2832 hasErr, C); 2833 if (hasErr) { 2834 ErrorRange = CallOrMsg.getReceiverSourceRange(); 2835 ErrorSym = Sym; 2836 } 2837 } 2838 } 2839 } 2840 2841 // Process any errors. 2842 if (hasErr) { 2843 processNonLeakError(state, ErrorRange, hasErr, ErrorSym, C); 2844 return; 2845 } 2846 2847 // Consult the summary for the return value. 2848 RetEffect RE = Summ.getRetEffect(); 2849 2850 if (RE.getKind() == RetEffect::OwnedWhenTrackedReceiver) { 2851 if (ReceiverIsTracked) 2852 RE = getSummaryManager(C).getObjAllocRetEffect(); 2853 else 2854 RE = RetEffect::MakeNoRet(); 2855 } 2856 2857 switch (RE.getKind()) { 2858 default: 2859 llvm_unreachable("Unhandled RetEffect."); 2860 2861 case RetEffect::NoRet: 2862 // No work necessary. 2863 break; 2864 2865 case RetEffect::OwnedAllocatedSymbol: 2866 case RetEffect::OwnedSymbol: { 2867 SymbolRef Sym = state->getSVal(CallOrMsg.getOriginExpr(), 2868 C.getLocationContext()).getAsSymbol(); 2869 if (!Sym) 2870 break; 2871 2872 // Use the result type from callOrMsg as it automatically adjusts 2873 // for methods/functions that return references. 2874 QualType ResultTy = CallOrMsg.getResultType(C.getASTContext()); 2875 state = state->set<RefBindings>(Sym, RefVal::makeOwned(RE.getObjKind(), 2876 ResultTy)); 2877 2878 // FIXME: Add a flag to the checker where allocations are assumed to 2879 // *not* fail. (The code below is out-of-date, though.) 2880#if 0 2881 if (RE.getKind() == RetEffect::OwnedAllocatedSymbol) { 2882 bool isFeasible; 2883 state = state.assume(loc::SymbolVal(Sym), true, isFeasible); 2884 assert(isFeasible && "Cannot assume fresh symbol is non-null."); 2885 } 2886#endif 2887 2888 break; 2889 } 2890 2891 case RetEffect::GCNotOwnedSymbol: 2892 case RetEffect::ARCNotOwnedSymbol: 2893 case RetEffect::NotOwnedSymbol: { 2894 const Expr *Ex = CallOrMsg.getOriginExpr(); 2895 SymbolRef Sym = state->getSVal(Ex, C.getLocationContext()).getAsSymbol(); 2896 if (!Sym) 2897 break; 2898 2899 // Use GetReturnType in order to give [NSFoo alloc] the type NSFoo *. 2900 QualType ResultTy = GetReturnType(Ex, C.getASTContext()); 2901 state = state->set<RefBindings>(Sym, RefVal::makeNotOwned(RE.getObjKind(), 2902 ResultTy)); 2903 break; 2904 } 2905 } 2906 2907 // This check is actually necessary; otherwise the statement builder thinks 2908 // we've hit a previously-found path. 2909 // Normally addTransition takes care of this, but we want the node pointer. 2910 ExplodedNode *NewNode; 2911 if (state == C.getState()) { 2912 NewNode = C.getPredecessor(); 2913 } else { 2914 NewNode = C.addTransition(state); 2915 } 2916 2917 // Annotate the node with summary we used. 2918 if (NewNode) { 2919 // FIXME: This is ugly. See checkEndAnalysis for why it's necessary. 2920 if (ShouldResetSummaryLog) { 2921 SummaryLog.clear(); 2922 ShouldResetSummaryLog = false; 2923 } 2924 SummaryLog[NewNode] = &Summ; 2925 } 2926} 2927 2928 2929ProgramStateRef 2930RetainCountChecker::updateSymbol(ProgramStateRef state, SymbolRef sym, 2931 RefVal V, ArgEffect E, RefVal::Kind &hasErr, 2932 CheckerContext &C) const { 2933 // In GC mode [... release] and [... retain] do nothing. 2934 // In ARC mode they shouldn't exist at all, but we just ignore them. 2935 bool IgnoreRetainMsg = C.isObjCGCEnabled(); 2936 if (!IgnoreRetainMsg) 2937 IgnoreRetainMsg = (bool)C.getASTContext().getLangOpts().ObjCAutoRefCount; 2938 2939 switch (E) { 2940 default: break; 2941 case IncRefMsg: E = IgnoreRetainMsg ? DoNothing : IncRef; break; 2942 case DecRefMsg: E = IgnoreRetainMsg ? DoNothing : DecRef; break; 2943 case MakeCollectable: E = C.isObjCGCEnabled() ? DecRef : DoNothing; break; 2944 case NewAutoreleasePool: E = C.isObjCGCEnabled() ? DoNothing : 2945 NewAutoreleasePool; break; 2946 } 2947 2948 // Handle all use-after-releases. 2949 if (!C.isObjCGCEnabled() && V.getKind() == RefVal::Released) { 2950 V = V ^ RefVal::ErrorUseAfterRelease; 2951 hasErr = V.getKind(); 2952 return state->set<RefBindings>(sym, V); 2953 } 2954 2955 switch (E) { 2956 case DecRefMsg: 2957 case IncRefMsg: 2958 case MakeCollectable: 2959 llvm_unreachable("DecRefMsg/IncRefMsg/MakeCollectable already converted"); 2960 2961 case Dealloc: 2962 // Any use of -dealloc in GC is *bad*. 2963 if (C.isObjCGCEnabled()) { 2964 V = V ^ RefVal::ErrorDeallocGC; 2965 hasErr = V.getKind(); 2966 break; 2967 } 2968 2969 switch (V.getKind()) { 2970 default: 2971 llvm_unreachable("Invalid RefVal state for an explicit dealloc."); 2972 case RefVal::Owned: 2973 // The object immediately transitions to the released state. 2974 V = V ^ RefVal::Released; 2975 V.clearCounts(); 2976 return state->set<RefBindings>(sym, V); 2977 case RefVal::NotOwned: 2978 V = V ^ RefVal::ErrorDeallocNotOwned; 2979 hasErr = V.getKind(); 2980 break; 2981 } 2982 break; 2983 2984 case NewAutoreleasePool: 2985 assert(!C.isObjCGCEnabled()); 2986 return state->add<AutoreleaseStack>(sym); 2987 2988 case MayEscape: 2989 if (V.getKind() == RefVal::Owned) { 2990 V = V ^ RefVal::NotOwned; 2991 break; 2992 } 2993 2994 // Fall-through. 2995 2996 case DoNothing: 2997 return state; 2998 2999 case Autorelease: 3000 if (C.isObjCGCEnabled()) 3001 return state; 3002 3003 // Update the autorelease counts. 3004 state = SendAutorelease(state, ARCountFactory, sym); 3005 V = V.autorelease(); 3006 break; 3007 3008 case StopTracking: 3009 return state->remove<RefBindings>(sym); 3010 3011 case IncRef: 3012 switch (V.getKind()) { 3013 default: 3014 llvm_unreachable("Invalid RefVal state for a retain."); 3015 case RefVal::Owned: 3016 case RefVal::NotOwned: 3017 V = V + 1; 3018 break; 3019 case RefVal::Released: 3020 // Non-GC cases are handled above. 3021 assert(C.isObjCGCEnabled()); 3022 V = (V ^ RefVal::Owned) + 1; 3023 break; 3024 } 3025 break; 3026 3027 case SelfOwn: 3028 V = V ^ RefVal::NotOwned; 3029 // Fall-through. 3030 case DecRef: 3031 case DecRefBridgedTransfered: 3032 switch (V.getKind()) { 3033 default: 3034 // case 'RefVal::Released' handled above. 3035 llvm_unreachable("Invalid RefVal state for a release."); 3036 3037 case RefVal::Owned: 3038 assert(V.getCount() > 0); 3039 if (V.getCount() == 1) 3040 V = V ^ (E == DecRefBridgedTransfered ? 3041 RefVal::NotOwned : RefVal::Released); 3042 V = V - 1; 3043 break; 3044 3045 case RefVal::NotOwned: 3046 if (V.getCount() > 0) 3047 V = V - 1; 3048 else { 3049 V = V ^ RefVal::ErrorReleaseNotOwned; 3050 hasErr = V.getKind(); 3051 } 3052 break; 3053 3054 case RefVal::Released: 3055 // Non-GC cases are handled above. 3056 assert(C.isObjCGCEnabled()); 3057 V = V ^ RefVal::ErrorUseAfterRelease; 3058 hasErr = V.getKind(); 3059 break; 3060 } 3061 break; 3062 } 3063 return state->set<RefBindings>(sym, V); 3064} 3065 3066void RetainCountChecker::processNonLeakError(ProgramStateRef St, 3067 SourceRange ErrorRange, 3068 RefVal::Kind ErrorKind, 3069 SymbolRef Sym, 3070 CheckerContext &C) const { 3071 ExplodedNode *N = C.generateSink(St); 3072 if (!N) 3073 return; 3074 3075 CFRefBug *BT; 3076 switch (ErrorKind) { 3077 default: 3078 llvm_unreachable("Unhandled error."); 3079 case RefVal::ErrorUseAfterRelease: 3080 if (!useAfterRelease) 3081 useAfterRelease.reset(new UseAfterRelease()); 3082 BT = &*useAfterRelease; 3083 break; 3084 case RefVal::ErrorReleaseNotOwned: 3085 if (!releaseNotOwned) 3086 releaseNotOwned.reset(new BadRelease()); 3087 BT = &*releaseNotOwned; 3088 break; 3089 case RefVal::ErrorDeallocGC: 3090 if (!deallocGC) 3091 deallocGC.reset(new DeallocGC()); 3092 BT = &*deallocGC; 3093 break; 3094 case RefVal::ErrorDeallocNotOwned: 3095 if (!deallocNotOwned) 3096 deallocNotOwned.reset(new DeallocNotOwned()); 3097 BT = &*deallocNotOwned; 3098 break; 3099 } 3100 3101 assert(BT); 3102 CFRefReport *report = new CFRefReport(*BT, C.getASTContext().getLangOpts(), 3103 C.isObjCGCEnabled(), SummaryLog, 3104 N, Sym); 3105 report->addRange(ErrorRange); 3106 C.EmitReport(report); 3107} 3108 3109//===----------------------------------------------------------------------===// 3110// Handle the return values of retain-count-related functions. 3111//===----------------------------------------------------------------------===// 3112 3113bool RetainCountChecker::evalCall(const CallExpr *CE, CheckerContext &C) const { 3114 // Get the callee. We're only interested in simple C functions. 3115 ProgramStateRef state = C.getState(); 3116 const FunctionDecl *FD = C.getCalleeDecl(CE); 3117 if (!FD) 3118 return false; 3119 3120 IdentifierInfo *II = FD->getIdentifier(); 3121 if (!II) 3122 return false; 3123 3124 // For now, we're only handling the functions that return aliases of their 3125 // arguments: CFRetain and CFMakeCollectable (and their families). 3126 // Eventually we should add other functions we can model entirely, 3127 // such as CFRelease, which don't invalidate their arguments or globals. 3128 if (CE->getNumArgs() != 1) 3129 return false; 3130 3131 // Get the name of the function. 3132 StringRef FName = II->getName(); 3133 FName = FName.substr(FName.find_first_not_of('_')); 3134 3135 // See if it's one of the specific functions we know how to eval. 3136 bool canEval = false; 3137 3138 QualType ResultTy = CE->getCallReturnType(); 3139 if (ResultTy->isObjCIdType()) { 3140 // Handle: id NSMakeCollectable(CFTypeRef) 3141 canEval = II->isStr("NSMakeCollectable"); 3142 } else if (ResultTy->isPointerType()) { 3143 // Handle: (CF|CG)Retain 3144 // CFMakeCollectable 3145 // It's okay to be a little sloppy here (CGMakeCollectable doesn't exist). 3146 if (cocoa::isRefType(ResultTy, "CF", FName) || 3147 cocoa::isRefType(ResultTy, "CG", FName)) { 3148 canEval = isRetain(FD, FName) || isMakeCollectable(FD, FName); 3149 } 3150 } 3151 3152 if (!canEval) 3153 return false; 3154 3155 // Bind the return value. 3156 const LocationContext *LCtx = C.getLocationContext(); 3157 SVal RetVal = state->getSVal(CE->getArg(0), LCtx); 3158 if (RetVal.isUnknown()) { 3159 // If the receiver is unknown, conjure a return value. 3160 SValBuilder &SVB = C.getSValBuilder(); 3161 unsigned Count = C.getCurrentBlockCount(); 3162 SVal RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count); 3163 } 3164 state = state->BindExpr(CE, LCtx, RetVal, false); 3165 3166 // FIXME: This should not be necessary, but otherwise the argument seems to be 3167 // considered alive during the next statement. 3168 if (const MemRegion *ArgRegion = RetVal.getAsRegion()) { 3169 // Save the refcount status of the argument. 3170 SymbolRef Sym = RetVal.getAsLocSymbol(); 3171 RefBindings::data_type *Binding = 0; 3172 if (Sym) 3173 Binding = state->get<RefBindings>(Sym); 3174 3175 // Invalidate the argument region. 3176 unsigned Count = C.getCurrentBlockCount(); 3177 state = state->invalidateRegions(ArgRegion, CE, Count, LCtx); 3178 3179 // Restore the refcount status of the argument. 3180 if (Binding) 3181 state = state->set<RefBindings>(Sym, *Binding); 3182 } 3183 3184 C.addTransition(state); 3185 return true; 3186} 3187 3188//===----------------------------------------------------------------------===// 3189// Handle return statements. 3190//===----------------------------------------------------------------------===// 3191 3192// Return true if the current LocationContext has no caller context. 3193static bool inTopFrame(CheckerContext &C) { 3194 const LocationContext *LC = C.getLocationContext(); 3195 return LC->getParent() == 0; 3196} 3197 3198void RetainCountChecker::checkPreStmt(const ReturnStmt *S, 3199 CheckerContext &C) const { 3200 3201 // Only adjust the reference count if this is the top-level call frame, 3202 // and not the result of inlining. In the future, we should do 3203 // better checking even for inlined calls, and see if they match 3204 // with their expected semantics (e.g., the method should return a retained 3205 // object, etc.). 3206 if (!inTopFrame(C)) 3207 return; 3208 3209 const Expr *RetE = S->getRetValue(); 3210 if (!RetE) 3211 return; 3212 3213 ProgramStateRef state = C.getState(); 3214 SymbolRef Sym = 3215 state->getSValAsScalarOrLoc(RetE, C.getLocationContext()).getAsLocSymbol(); 3216 if (!Sym) 3217 return; 3218 3219 // Get the reference count binding (if any). 3220 const RefVal *T = state->get<RefBindings>(Sym); 3221 if (!T) 3222 return; 3223 3224 // Change the reference count. 3225 RefVal X = *T; 3226 3227 switch (X.getKind()) { 3228 case RefVal::Owned: { 3229 unsigned cnt = X.getCount(); 3230 assert(cnt > 0); 3231 X.setCount(cnt - 1); 3232 X = X ^ RefVal::ReturnedOwned; 3233 break; 3234 } 3235 3236 case RefVal::NotOwned: { 3237 unsigned cnt = X.getCount(); 3238 if (cnt) { 3239 X.setCount(cnt - 1); 3240 X = X ^ RefVal::ReturnedOwned; 3241 } 3242 else { 3243 X = X ^ RefVal::ReturnedNotOwned; 3244 } 3245 break; 3246 } 3247 3248 default: 3249 return; 3250 } 3251 3252 // Update the binding. 3253 state = state->set<RefBindings>(Sym, X); 3254 ExplodedNode *Pred = C.addTransition(state); 3255 3256 // At this point we have updated the state properly. 3257 // Everything after this is merely checking to see if the return value has 3258 // been over- or under-retained. 3259 3260 // Did we cache out? 3261 if (!Pred) 3262 return; 3263 3264 // Update the autorelease counts. 3265 static SimpleProgramPointTag 3266 AutoreleaseTag("RetainCountChecker : Autorelease"); 3267 GenericNodeBuilderRefCount Bd(C, &AutoreleaseTag); 3268 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, Sym, X); 3269 3270 // Did we cache out? 3271 if (!Pred) 3272 return; 3273 3274 // Get the updated binding. 3275 T = state->get<RefBindings>(Sym); 3276 assert(T); 3277 X = *T; 3278 3279 // Consult the summary of the enclosing method. 3280 RetainSummaryManager &Summaries = getSummaryManager(C); 3281 const Decl *CD = &Pred->getCodeDecl(); 3282 3283 if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CD)) { 3284 // Unlike regular functions, /all/ ObjC methods are assumed to always 3285 // follow Cocoa retain-count conventions, not just those with special 3286 // names or attributes. 3287 const RetainSummary *Summ = Summaries.getMethodSummary(MD); 3288 RetEffect RE = Summ ? Summ->getRetEffect() : RetEffect::MakeNoRet(); 3289 checkReturnWithRetEffect(S, C, Pred, RE, X, Sym, state); 3290 } 3291 3292 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CD)) { 3293 if (!isa<CXXMethodDecl>(FD)) 3294 if (const RetainSummary *Summ = Summaries.getSummary(FD, 0)) 3295 checkReturnWithRetEffect(S, C, Pred, Summ->getRetEffect(), X, 3296 Sym, state); 3297 } 3298} 3299 3300void RetainCountChecker::checkReturnWithRetEffect(const ReturnStmt *S, 3301 CheckerContext &C, 3302 ExplodedNode *Pred, 3303 RetEffect RE, RefVal X, 3304 SymbolRef Sym, 3305 ProgramStateRef state) const { 3306 // Any leaks or other errors? 3307 if (X.isReturnedOwned() && X.getCount() == 0) { 3308 if (RE.getKind() != RetEffect::NoRet) { 3309 bool hasError = false; 3310 if (C.isObjCGCEnabled() && RE.getObjKind() == RetEffect::ObjC) { 3311 // Things are more complicated with garbage collection. If the 3312 // returned object is suppose to be an Objective-C object, we have 3313 // a leak (as the caller expects a GC'ed object) because no 3314 // method should return ownership unless it returns a CF object. 3315 hasError = true; 3316 X = X ^ RefVal::ErrorGCLeakReturned; 3317 } 3318 else if (!RE.isOwned()) { 3319 // Either we are using GC and the returned object is a CF type 3320 // or we aren't using GC. In either case, we expect that the 3321 // enclosing method is expected to return ownership. 3322 hasError = true; 3323 X = X ^ RefVal::ErrorLeakReturned; 3324 } 3325 3326 if (hasError) { 3327 // Generate an error node. 3328 state = state->set<RefBindings>(Sym, X); 3329 3330 static SimpleProgramPointTag 3331 ReturnOwnLeakTag("RetainCountChecker : ReturnsOwnLeak"); 3332 ExplodedNode *N = C.addTransition(state, Pred, &ReturnOwnLeakTag); 3333 if (N) { 3334 const LangOptions &LOpts = C.getASTContext().getLangOpts(); 3335 bool GCEnabled = C.isObjCGCEnabled(); 3336 CFRefReport *report = 3337 new CFRefLeakReport(*getLeakAtReturnBug(LOpts, GCEnabled), 3338 LOpts, GCEnabled, SummaryLog, 3339 N, Sym, C); 3340 C.EmitReport(report); 3341 } 3342 } 3343 } 3344 } else if (X.isReturnedNotOwned()) { 3345 if (RE.isOwned()) { 3346 // Trying to return a not owned object to a caller expecting an 3347 // owned object. 3348 state = state->set<RefBindings>(Sym, X ^ RefVal::ErrorReturnedNotOwned); 3349 3350 static SimpleProgramPointTag 3351 ReturnNotOwnedTag("RetainCountChecker : ReturnNotOwnedForOwned"); 3352 ExplodedNode *N = C.addTransition(state, Pred, &ReturnNotOwnedTag); 3353 if (N) { 3354 if (!returnNotOwnedForOwned) 3355 returnNotOwnedForOwned.reset(new ReturnedNotOwnedForOwned()); 3356 3357 CFRefReport *report = 3358 new CFRefReport(*returnNotOwnedForOwned, 3359 C.getASTContext().getLangOpts(), 3360 C.isObjCGCEnabled(), SummaryLog, N, Sym); 3361 C.EmitReport(report); 3362 } 3363 } 3364 } 3365} 3366 3367//===----------------------------------------------------------------------===// 3368// Check various ways a symbol can be invalidated. 3369//===----------------------------------------------------------------------===// 3370 3371void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S, 3372 CheckerContext &C) const { 3373 // Are we storing to something that causes the value to "escape"? 3374 bool escapes = true; 3375 3376 // A value escapes in three possible cases (this may change): 3377 // 3378 // (1) we are binding to something that is not a memory region. 3379 // (2) we are binding to a memregion that does not have stack storage 3380 // (3) we are binding to a memregion with stack storage that the store 3381 // does not understand. 3382 ProgramStateRef state = C.getState(); 3383 3384 if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { 3385 escapes = !regionLoc->getRegion()->hasStackStorage(); 3386 3387 if (!escapes) { 3388 // To test (3), generate a new state with the binding added. If it is 3389 // the same state, then it escapes (since the store cannot represent 3390 // the binding). 3391 // Do this only if we know that the store is not supposed to generate the 3392 // same state. 3393 SVal StoredVal = state->getSVal(regionLoc->getRegion()); 3394 if (StoredVal != val) 3395 escapes = (state == (state->bindLoc(*regionLoc, val))); 3396 } 3397 if (!escapes) { 3398 // Case 4: We do not currently model what happens when a symbol is 3399 // assigned to a struct field, so be conservative here and let the symbol 3400 // go. TODO: This could definitely be improved upon. 3401 escapes = !isa<VarRegion>(regionLoc->getRegion()); 3402 } 3403 } 3404 3405 // If our store can represent the binding and we aren't storing to something 3406 // that doesn't have local storage then just return and have the simulation 3407 // state continue as is. 3408 if (!escapes) 3409 return; 3410 3411 // Otherwise, find all symbols referenced by 'val' that we are tracking 3412 // and stop tracking them. 3413 state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); 3414 C.addTransition(state); 3415} 3416 3417ProgramStateRef RetainCountChecker::evalAssume(ProgramStateRef state, 3418 SVal Cond, 3419 bool Assumption) const { 3420 3421 // FIXME: We may add to the interface of evalAssume the list of symbols 3422 // whose assumptions have changed. For now we just iterate through the 3423 // bindings and check if any of the tracked symbols are NULL. This isn't 3424 // too bad since the number of symbols we will track in practice are 3425 // probably small and evalAssume is only called at branches and a few 3426 // other places. 3427 RefBindings B = state->get<RefBindings>(); 3428 3429 if (B.isEmpty()) 3430 return state; 3431 3432 bool changed = false; 3433 RefBindings::Factory &RefBFactory = state->get_context<RefBindings>(); 3434 3435 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3436 // Check if the symbol is null (or equal to any constant). 3437 // If this is the case, stop tracking the symbol. 3438 if (state->getSymVal(I.getKey())) { 3439 changed = true; 3440 B = RefBFactory.remove(B, I.getKey()); 3441 } 3442 } 3443 3444 if (changed) 3445 state = state->set<RefBindings>(B); 3446 3447 return state; 3448} 3449 3450ProgramStateRef 3451RetainCountChecker::checkRegionChanges(ProgramStateRef state, 3452 const StoreManager::InvalidatedSymbols *invalidated, 3453 ArrayRef<const MemRegion *> ExplicitRegions, 3454 ArrayRef<const MemRegion *> Regions, 3455 const CallOrObjCMessage *Call) const { 3456 if (!invalidated) 3457 return state; 3458 3459 llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; 3460 for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), 3461 E = ExplicitRegions.end(); I != E; ++I) { 3462 if (const SymbolicRegion *SR = (*I)->StripCasts()->getAs<SymbolicRegion>()) 3463 WhitelistedSymbols.insert(SR->getSymbol()); 3464 } 3465 3466 for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), 3467 E = invalidated->end(); I!=E; ++I) { 3468 SymbolRef sym = *I; 3469 if (WhitelistedSymbols.count(sym)) 3470 continue; 3471 // Remove any existing reference-count binding. 3472 state = state->remove<RefBindings>(sym); 3473 } 3474 return state; 3475} 3476 3477//===----------------------------------------------------------------------===// 3478// Handle dead symbols and end-of-path. 3479//===----------------------------------------------------------------------===// 3480 3481std::pair<ExplodedNode *, ProgramStateRef > 3482RetainCountChecker::handleAutoreleaseCounts(ProgramStateRef state, 3483 GenericNodeBuilderRefCount Bd, 3484 ExplodedNode *Pred, 3485 CheckerContext &Ctx, 3486 SymbolRef Sym, RefVal V) const { 3487 unsigned ACnt = V.getAutoreleaseCount(); 3488 3489 // No autorelease counts? Nothing to be done. 3490 if (!ACnt) 3491 return std::make_pair(Pred, state); 3492 3493 assert(!Ctx.isObjCGCEnabled() && "Autorelease counts in GC mode?"); 3494 unsigned Cnt = V.getCount(); 3495 3496 // FIXME: Handle sending 'autorelease' to already released object. 3497 3498 if (V.getKind() == RefVal::ReturnedOwned) 3499 ++Cnt; 3500 3501 if (ACnt <= Cnt) { 3502 if (ACnt == Cnt) { 3503 V.clearCounts(); 3504 if (V.getKind() == RefVal::ReturnedOwned) 3505 V = V ^ RefVal::ReturnedNotOwned; 3506 else 3507 V = V ^ RefVal::NotOwned; 3508 } else { 3509 V.setCount(Cnt - ACnt); 3510 V.setAutoreleaseCount(0); 3511 } 3512 state = state->set<RefBindings>(Sym, V); 3513 ExplodedNode *N = Bd.MakeNode(state, Pred); 3514 if (N == 0) 3515 state = 0; 3516 return std::make_pair(N, state); 3517 } 3518 3519 // Woah! More autorelease counts then retain counts left. 3520 // Emit hard error. 3521 V = V ^ RefVal::ErrorOverAutorelease; 3522 state = state->set<RefBindings>(Sym, V); 3523 3524 if (ExplodedNode *N = Bd.MakeNode(state, Pred, true)) { 3525 SmallString<128> sbuf; 3526 llvm::raw_svector_ostream os(sbuf); 3527 os << "Object over-autoreleased: object was sent -autorelease "; 3528 if (V.getAutoreleaseCount() > 1) 3529 os << V.getAutoreleaseCount() << " times "; 3530 os << "but the object has a +" << V.getCount() << " retain count"; 3531 3532 if (!overAutorelease) 3533 overAutorelease.reset(new OverAutorelease()); 3534 3535 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3536 CFRefReport *report = 3537 new CFRefReport(*overAutorelease, LOpts, /* GCEnabled = */ false, 3538 SummaryLog, N, Sym, os.str()); 3539 Ctx.EmitReport(report); 3540 } 3541 3542 return std::make_pair((ExplodedNode *)0, (ProgramStateRef )0); 3543} 3544 3545ProgramStateRef 3546RetainCountChecker::handleSymbolDeath(ProgramStateRef state, 3547 SymbolRef sid, RefVal V, 3548 SmallVectorImpl<SymbolRef> &Leaked) const { 3549 bool hasLeak = false; 3550 if (V.isOwned()) 3551 hasLeak = true; 3552 else if (V.isNotOwned() || V.isReturnedOwned()) 3553 hasLeak = (V.getCount() > 0); 3554 3555 if (!hasLeak) 3556 return state->remove<RefBindings>(sid); 3557 3558 Leaked.push_back(sid); 3559 return state->set<RefBindings>(sid, V ^ RefVal::ErrorLeak); 3560} 3561 3562ExplodedNode * 3563RetainCountChecker::processLeaks(ProgramStateRef state, 3564 SmallVectorImpl<SymbolRef> &Leaked, 3565 GenericNodeBuilderRefCount &Builder, 3566 CheckerContext &Ctx, 3567 ExplodedNode *Pred) const { 3568 if (Leaked.empty()) 3569 return Pred; 3570 3571 // Generate an intermediate node representing the leak point. 3572 ExplodedNode *N = Builder.MakeNode(state, Pred); 3573 3574 if (N) { 3575 for (SmallVectorImpl<SymbolRef>::iterator 3576 I = Leaked.begin(), E = Leaked.end(); I != E; ++I) { 3577 3578 const LangOptions &LOpts = Ctx.getASTContext().getLangOpts(); 3579 bool GCEnabled = Ctx.isObjCGCEnabled(); 3580 CFRefBug *BT = Pred ? getLeakWithinFunctionBug(LOpts, GCEnabled) 3581 : getLeakAtReturnBug(LOpts, GCEnabled); 3582 assert(BT && "BugType not initialized."); 3583 3584 CFRefLeakReport *report = new CFRefLeakReport(*BT, LOpts, GCEnabled, 3585 SummaryLog, N, *I, Ctx); 3586 Ctx.EmitReport(report); 3587 } 3588 } 3589 3590 return N; 3591} 3592 3593void RetainCountChecker::checkEndPath(CheckerContext &Ctx) const { 3594 ProgramStateRef state = Ctx.getState(); 3595 GenericNodeBuilderRefCount Bd(Ctx); 3596 RefBindings B = state->get<RefBindings>(); 3597 ExplodedNode *Pred = Ctx.getPredecessor(); 3598 3599 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3600 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, Ctx, 3601 I->first, I->second); 3602 if (!state) 3603 return; 3604 } 3605 3606 // If the current LocationContext has a parent, don't check for leaks. 3607 // We will do that later. 3608 // FIXME: we should instead check for imblances of the retain/releases, 3609 // and suggest annotations. 3610 if (Ctx.getLocationContext()->getParent()) 3611 return; 3612 3613 B = state->get<RefBindings>(); 3614 SmallVector<SymbolRef, 10> Leaked; 3615 3616 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) 3617 state = handleSymbolDeath(state, I->first, I->second, Leaked); 3618 3619 processLeaks(state, Leaked, Bd, Ctx, Pred); 3620} 3621 3622const ProgramPointTag * 3623RetainCountChecker::getDeadSymbolTag(SymbolRef sym) const { 3624 const SimpleProgramPointTag *&tag = DeadSymbolTags[sym]; 3625 if (!tag) { 3626 SmallString<64> buf; 3627 llvm::raw_svector_ostream out(buf); 3628 out << "RetainCountChecker : Dead Symbol : "; 3629 sym->dumpToStream(out); 3630 tag = new SimpleProgramPointTag(out.str()); 3631 } 3632 return tag; 3633} 3634 3635void RetainCountChecker::checkDeadSymbols(SymbolReaper &SymReaper, 3636 CheckerContext &C) const { 3637 ExplodedNode *Pred = C.getPredecessor(); 3638 3639 ProgramStateRef state = C.getState(); 3640 RefBindings B = state->get<RefBindings>(); 3641 3642 // Update counts from autorelease pools 3643 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3644 E = SymReaper.dead_end(); I != E; ++I) { 3645 SymbolRef Sym = *I; 3646 if (const RefVal *T = B.lookup(Sym)){ 3647 // Use the symbol as the tag. 3648 // FIXME: This might not be as unique as we would like. 3649 GenericNodeBuilderRefCount Bd(C, getDeadSymbolTag(Sym)); 3650 llvm::tie(Pred, state) = handleAutoreleaseCounts(state, Bd, Pred, C, 3651 Sym, *T); 3652 if (!state) 3653 return; 3654 } 3655 } 3656 3657 B = state->get<RefBindings>(); 3658 SmallVector<SymbolRef, 10> Leaked; 3659 3660 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3661 E = SymReaper.dead_end(); I != E; ++I) { 3662 if (const RefVal *T = B.lookup(*I)) 3663 state = handleSymbolDeath(state, *I, *T, Leaked); 3664 } 3665 3666 { 3667 GenericNodeBuilderRefCount Bd(C, this); 3668 Pred = processLeaks(state, Leaked, Bd, C, Pred); 3669 } 3670 3671 // Did we cache out? 3672 if (!Pred) 3673 return; 3674 3675 // Now generate a new node that nukes the old bindings. 3676 RefBindings::Factory &F = state->get_context<RefBindings>(); 3677 3678 for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(), 3679 E = SymReaper.dead_end(); I != E; ++I) 3680 B = F.remove(B, *I); 3681 3682 state = state->set<RefBindings>(B); 3683 C.addTransition(state, Pred); 3684} 3685 3686//===----------------------------------------------------------------------===// 3687// Debug printing of refcount bindings and autorelease pools. 3688//===----------------------------------------------------------------------===// 3689 3690static void PrintPool(raw_ostream &Out, SymbolRef Sym, 3691 ProgramStateRef State) { 3692 Out << ' '; 3693 if (Sym) 3694 Sym->dumpToStream(Out); 3695 else 3696 Out << "<pool>"; 3697 Out << ":{"; 3698 3699 // Get the contents of the pool. 3700 if (const ARCounts *Cnts = State->get<AutoreleasePoolContents>(Sym)) 3701 for (ARCounts::iterator I = Cnts->begin(), E = Cnts->end(); I != E; ++I) 3702 Out << '(' << I.getKey() << ',' << I.getData() << ')'; 3703 3704 Out << '}'; 3705} 3706 3707static bool UsesAutorelease(ProgramStateRef state) { 3708 // A state uses autorelease if it allocated an autorelease pool or if it has 3709 // objects in the caller's autorelease pool. 3710 return !state->get<AutoreleaseStack>().isEmpty() || 3711 state->get<AutoreleasePoolContents>(SymbolRef()); 3712} 3713 3714void RetainCountChecker::printState(raw_ostream &Out, ProgramStateRef State, 3715 const char *NL, const char *Sep) const { 3716 3717 RefBindings B = State->get<RefBindings>(); 3718 3719 if (!B.isEmpty()) 3720 Out << Sep << NL; 3721 3722 for (RefBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) { 3723 Out << I->first << " : "; 3724 I->second.print(Out); 3725 Out << NL; 3726 } 3727 3728 // Print the autorelease stack. 3729 if (UsesAutorelease(State)) { 3730 Out << Sep << NL << "AR pool stack:"; 3731 ARStack Stack = State->get<AutoreleaseStack>(); 3732 3733 PrintPool(Out, SymbolRef(), State); // Print the caller's pool. 3734 for (ARStack::iterator I = Stack.begin(), E = Stack.end(); I != E; ++I) 3735 PrintPool(Out, *I, State); 3736 3737 Out << NL; 3738 } 3739} 3740 3741//===----------------------------------------------------------------------===// 3742// Checker registration. 3743//===----------------------------------------------------------------------===// 3744 3745void ento::registerRetainCountChecker(CheckerManager &Mgr) { 3746 Mgr.registerChecker<RetainCountChecker>(); 3747} 3748 3749